BoringSSL as optional cryptobackend for ngtcp2

PR добавляет возможность использовать BoringSSL в ngtcp2 в качестве криптобиблиотеки. Для проектов в Аркадии, уже зависящих от ngtcp2, добавлена явная зависимость от слоя абстракции quictls (сейчас в транке ngtcp2 собирается с quictls).
commit_hash:3d6607abecfcff2157859acbdd18f9d0345ac485

1 files changed, 6101 insertions, 0 deletions

diff --git a/contrib/restricted/google/boringssl/include/openssl/ssl.h b/contrib/restricted/google/boringssl/include/openssl/ssl.h
new file mode 100644
index 00000000000..0b2603535e7
--- /dev/null
+++ b/contrib/restricted/google/boringssl/include/openssl/ssl.h
@@ -0,0 +1,6101 @@
+/* Copyright (C) 1995-1998 Eric Young ([email protected])
+ * All rights reserved.
+ *
+ * This package is an SSL implementation written
+ * by Eric Young ([email protected]).
+ * The implementation was written so as to conform with Netscapes SSL.
+ *
+ * This library is free for commercial and non-commercial use as long as
+ * the following conditions are aheared to.  The following conditions
+ * apply to all code found in this distribution, be it the RC4, RSA,
+ * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
+ * included with this distribution is covered by the same copyright terms
+ * except that the holder is Tim Hudson ([email protected]).
+ *
+ * Copyright remains Eric Young's, and as such any Copyright notices in
+ * the code are not to be removed.
+ * If this package is used in a product, Eric Young should be given attribution
+ * as the author of the parts of the library used.
+ * This can be in the form of a textual message at program startup or
+ * in documentation (online or textual) provided with the package.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *    "This product includes cryptographic software written by
+ *     Eric Young ([email protected])"
+ *    The word 'cryptographic' can be left out if the rouines from the library
+ *    being used are not cryptographic related :-).
+ * 4. If you include any Windows specific code (or a derivative thereof) from
+ *    the apps directory (application code) you must include an acknowledgement:
+ *    "This product includes software written by Tim Hudson ([email protected])"
+ *
+ * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * The licence and distribution terms for any publically available version or
+ * derivative of this code cannot be changed.  i.e. this code cannot simply be
+ * copied and put under another distribution licence
+ * [including the GNU Public Licence.]
+ */
+/* ====================================================================
+ * Copyright (c) 1998-2007 The OpenSSL Project.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. All advertising materials mentioning features or use of this
+ *    software must display the following acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ *    endorse or promote products derived from this software without
+ *    prior written permission. For written permission, please contact
+ *    [email protected].
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ *    nor may "OpenSSL" appear in their names without prior written
+ *    permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ *    acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This product includes cryptographic software written by Eric Young
+ * ([email protected]).  This product includes software written by Tim
+ * Hudson ([email protected]).
+ *
+ */
+/* ====================================================================
+ * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
+ * ECC cipher suite support in OpenSSL originally developed by
+ * SUN MICROSYSTEMS, INC., and contributed to the OpenSSL project.
+ */
+/* ====================================================================
+ * Copyright 2005 Nokia. All rights reserved.
+ *
+ * The portions of the attached software ("Contribution") is developed by
+ * Nokia Corporation and is licensed pursuant to the OpenSSL open source
+ * license.
+ *
+ * The Contribution, originally written by Mika Kousa and Pasi Eronen of
+ * Nokia Corporation, consists of the "PSK" (Pre-Shared Key) ciphersuites
+ * support (see RFC 4279) to OpenSSL.
+ *
+ * No patent licenses or other rights except those expressly stated in
+ * the OpenSSL open source license shall be deemed granted or received
+ * expressly, by implication, estoppel, or otherwise.
+ *
+ * No assurances are provided by Nokia that the Contribution does not
+ * infringe the patent or other intellectual property rights of any third
+ * party or that the license provides you with all the necessary rights
+ * to make use of the Contribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. IN
+ * ADDITION TO THE DISCLAIMERS INCLUDED IN THE LICENSE, NOKIA
+ * SPECIFICALLY DISCLAIMS ANY LIABILITY FOR CLAIMS BROUGHT BY YOU OR ANY
+ * OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OR
+ * OTHERWISE.
+ */
+
+#ifndef OPENSSL_HEADER_SSL_H
+#define OPENSSL_HEADER_SSL_H
+
+#include <contrib/restricted/google/boringssl/include/openssl/base.h>
+
+#include <contrib/restricted/google/boringssl/include/openssl/bio.h>
+#include <contrib/restricted/google/boringssl/include/openssl/buf.h>
+#include <contrib/restricted/google/boringssl/include/openssl/pem.h>
+#include <contrib/restricted/google/boringssl/include/openssl/span.h>
+#include <contrib/restricted/google/boringssl/include/openssl/ssl3.h>
+#include <contrib/restricted/google/boringssl/include/openssl/thread.h>
+#include <contrib/restricted/google/boringssl/include/openssl/tls1.h>
+#include <contrib/restricted/google/boringssl/include/openssl/x509.h>
+
+#if !defined(OPENSSL_WINDOWS)
+#include <sys/time.h>
+#endif
+
+// Forward-declare struct timeval. On Windows, it is defined in winsock2.h and
+// Windows headers define too many macros to be included in public headers.
+// However, only a forward declaration is needed.
+struct timeval;
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+
+// SSL implementation.
+
+
+// SSL contexts.
+//
+// |SSL_CTX| objects manage shared state and configuration between multiple TLS
+// or DTLS connections. Whether the connections are TLS or DTLS is selected by
+// an |SSL_METHOD| on creation.
+//
+// |SSL_CTX| are reference-counted and may be shared by connections across
+// multiple threads. Once shared, functions which change the |SSL_CTX|'s
+// configuration may not be used.
+
+// TLS_method is the |SSL_METHOD| used for TLS connections.
+OPENSSL_EXPORT const SSL_METHOD *TLS_method(void);
+
+// DTLS_method is the |SSL_METHOD| used for DTLS connections.
+OPENSSL_EXPORT const SSL_METHOD *DTLS_method(void);
+
+// TLS_with_buffers_method is like |TLS_method|, but avoids all use of
+// crypto/x509. All client connections created with |TLS_with_buffers_method|
+// will fail unless a certificate verifier is installed with
+// |SSL_set_custom_verify| or |SSL_CTX_set_custom_verify|.
+OPENSSL_EXPORT const SSL_METHOD *TLS_with_buffers_method(void);
+
+// DTLS_with_buffers_method is like |DTLS_method|, but avoids all use of
+// crypto/x509.
+OPENSSL_EXPORT const SSL_METHOD *DTLS_with_buffers_method(void);
+
+// SSL_CTX_new returns a newly-allocated |SSL_CTX| with default settings or NULL
+// on error.
+OPENSSL_EXPORT SSL_CTX *SSL_CTX_new(const SSL_METHOD *method);
+
+// SSL_CTX_up_ref increments the reference count of |ctx|. It returns one.
+OPENSSL_EXPORT int SSL_CTX_up_ref(SSL_CTX *ctx);
+
+// SSL_CTX_free releases memory associated with |ctx|.
+OPENSSL_EXPORT void SSL_CTX_free(SSL_CTX *ctx);
+
+
+// SSL connections.
+//
+// An |SSL| object represents a single TLS or DTLS connection. Although the
+// shared |SSL_CTX| is thread-safe, an |SSL| is not thread-safe and may only be
+// used on one thread at a time.
+
+// SSL_new returns a newly-allocated |SSL| using |ctx| or NULL on error. The new
+// connection inherits settings from |ctx| at the time of creation. Settings may
+// also be individually configured on the connection.
+//
+// On creation, an |SSL| is not configured to be either a client or server. Call
+// |SSL_set_connect_state| or |SSL_set_accept_state| to set this.
+OPENSSL_EXPORT SSL *SSL_new(SSL_CTX *ctx);
+
+// SSL_free releases memory associated with |ssl|.
+OPENSSL_EXPORT void SSL_free(SSL *ssl);
+
+// SSL_get_SSL_CTX returns the |SSL_CTX| associated with |ssl|. If
+// |SSL_set_SSL_CTX| is called, it returns the new |SSL_CTX|, not the initial
+// one.
+OPENSSL_EXPORT SSL_CTX *SSL_get_SSL_CTX(const SSL *ssl);
+
+// SSL_set_connect_state configures |ssl| to be a client.
+OPENSSL_EXPORT void SSL_set_connect_state(SSL *ssl);
+
+// SSL_set_accept_state configures |ssl| to be a server.
+OPENSSL_EXPORT void SSL_set_accept_state(SSL *ssl);
+
+// SSL_is_server returns one if |ssl| is configured as a server and zero
+// otherwise.
+OPENSSL_EXPORT int SSL_is_server(const SSL *ssl);
+
+// SSL_is_dtls returns one if |ssl| is a DTLS connection and zero otherwise.
+OPENSSL_EXPORT int SSL_is_dtls(const SSL *ssl);
+
+// SSL_set_bio configures |ssl| to read from |rbio| and write to |wbio|. |ssl|
+// takes ownership of the two |BIO|s. If |rbio| and |wbio| are the same, |ssl|
+// only takes ownership of one reference.
+//
+// In DTLS, |rbio| must be non-blocking to properly handle timeouts and
+// retransmits.
+//
+// If |rbio| is the same as the currently configured |BIO| for reading, that
+// side is left untouched and is not freed.
+//
+// If |wbio| is the same as the currently configured |BIO| for writing AND |ssl|
+// is not currently configured to read from and write to the same |BIO|, that
+// side is left untouched and is not freed. This asymmetry is present for
+// historical reasons.
+//
+// Due to the very complex historical behavior of this function, calling this
+// function if |ssl| already has |BIO|s configured is deprecated. Prefer
+// |SSL_set0_rbio| and |SSL_set0_wbio| instead.
+OPENSSL_EXPORT void SSL_set_bio(SSL *ssl, BIO *rbio, BIO *wbio);
+
+// SSL_set0_rbio configures |ssl| to read from |rbio|. It takes ownership of
+// |rbio|.
+//
+// Note that, although this function and |SSL_set0_wbio| may be called on the
+// same |BIO|, each call takes a reference. Use |BIO_up_ref| to balance this.
+OPENSSL_EXPORT void SSL_set0_rbio(SSL *ssl, BIO *rbio);
+
+// SSL_set0_wbio configures |ssl| to write to |wbio|. It takes ownership of
+// |wbio|.
+//
+// Note that, although this function and |SSL_set0_rbio| may be called on the
+// same |BIO|, each call takes a reference. Use |BIO_up_ref| to balance this.
+OPENSSL_EXPORT void SSL_set0_wbio(SSL *ssl, BIO *wbio);
+
+// SSL_get_rbio returns the |BIO| that |ssl| reads from.
+OPENSSL_EXPORT BIO *SSL_get_rbio(const SSL *ssl);
+
+// SSL_get_wbio returns the |BIO| that |ssl| writes to.
+OPENSSL_EXPORT BIO *SSL_get_wbio(const SSL *ssl);
+
+// SSL_get_fd calls |SSL_get_rfd|.
+OPENSSL_EXPORT int SSL_get_fd(const SSL *ssl);
+
+// SSL_get_rfd returns the file descriptor that |ssl| is configured to read
+// from. If |ssl|'s read |BIO| is not configured or doesn't wrap a file
+// descriptor then it returns -1.
+//
+// Note: On Windows, this may return either a file descriptor or a socket (cast
+// to int), depending on whether |ssl| was configured with a file descriptor or
+// socket |BIO|.
+OPENSSL_EXPORT int SSL_get_rfd(const SSL *ssl);
+
+// SSL_get_wfd returns the file descriptor that |ssl| is configured to write
+// to. If |ssl|'s write |BIO| is not configured or doesn't wrap a file
+// descriptor then it returns -1.
+//
+// Note: On Windows, this may return either a file descriptor or a socket (cast
+// to int), depending on whether |ssl| was configured with a file descriptor or
+// socket |BIO|.
+OPENSSL_EXPORT int SSL_get_wfd(const SSL *ssl);
+
+#if !defined(OPENSSL_NO_SOCK)
+// SSL_set_fd configures |ssl| to read from and write to |fd|. It returns one
+// on success and zero on allocation error. The caller retains ownership of
+// |fd|.
+//
+// On Windows, |fd| is cast to a |SOCKET| and used with Winsock APIs.
+OPENSSL_EXPORT int SSL_set_fd(SSL *ssl, int fd);
+
+// SSL_set_rfd configures |ssl| to read from |fd|. It returns one on success and
+// zero on allocation error. The caller retains ownership of |fd|.
+//
+// On Windows, |fd| is cast to a |SOCKET| and used with Winsock APIs.
+OPENSSL_EXPORT int SSL_set_rfd(SSL *ssl, int fd);
+
+// SSL_set_wfd configures |ssl| to write to |fd|. It returns one on success and
+// zero on allocation error. The caller retains ownership of |fd|.
+//
+// On Windows, |fd| is cast to a |SOCKET| and used with Winsock APIs.
+OPENSSL_EXPORT int SSL_set_wfd(SSL *ssl, int fd);
+#endif  // !OPENSSL_NO_SOCK
+
+// SSL_do_handshake continues the current handshake. If there is none or the
+// handshake has completed or False Started, it returns one. Otherwise, it
+// returns <= 0. The caller should pass the value into |SSL_get_error| to
+// determine how to proceed.
+//
+// In DTLS, the caller must drive retransmissions. Whenever |SSL_get_error|
+// signals |SSL_ERROR_WANT_READ|, use |DTLSv1_get_timeout| to determine the
+// current timeout. If it expires before the next retry, call
+// |DTLSv1_handle_timeout|. Note that DTLS handshake retransmissions use fresh
+// sequence numbers, so it is not sufficient to replay packets at the transport.
+//
+// TODO(davidben): Ensure 0 is only returned on transport EOF.
+// https://crbug.com/466303.
+OPENSSL_EXPORT int SSL_do_handshake(SSL *ssl);
+
+// SSL_connect configures |ssl| as a client, if unconfigured, and calls
+// |SSL_do_handshake|.
+OPENSSL_EXPORT int SSL_connect(SSL *ssl);
+
+// SSL_accept configures |ssl| as a server, if unconfigured, and calls
+// |SSL_do_handshake|.
+OPENSSL_EXPORT int SSL_accept(SSL *ssl);
+
+// SSL_read reads up to |num| bytes from |ssl| into |buf|. It implicitly runs
+// any pending handshakes, including renegotiations when enabled. On success, it
+// returns the number of bytes read. Otherwise, it returns <= 0. The caller
+// should pass the value into |SSL_get_error| to determine how to proceed.
+//
+// TODO(davidben): Ensure 0 is only returned on transport EOF.
+// https://crbug.com/466303.
+OPENSSL_EXPORT int SSL_read(SSL *ssl, void *buf, int num);
+
+// SSL_peek behaves like |SSL_read| but does not consume any bytes returned.
+OPENSSL_EXPORT int SSL_peek(SSL *ssl, void *buf, int num);
+
+// SSL_pending returns the number of buffered, decrypted bytes available for
+// read in |ssl|. It does not read from the transport.
+//
+// In DTLS, it is possible for this function to return zero while there is
+// buffered, undecrypted data from the transport in |ssl|. For example,
+// |SSL_read| may read a datagram with two records, decrypt the first, and leave
+// the second buffered for a subsequent call to |SSL_read|. Callers that wish to
+// detect this case can use |SSL_has_pending|.
+OPENSSL_EXPORT int SSL_pending(const SSL *ssl);
+
+// SSL_has_pending returns one if |ssl| has buffered, decrypted bytes available
+// for read, or if |ssl| has buffered data from the transport that has not yet
+// been decrypted. If |ssl| has neither, this function returns zero.
+//
+// In TLS, BoringSSL does not implement read-ahead, so this function returns one
+// if and only if |SSL_pending| would return a non-zero value. In DTLS, it is
+// possible for this function to return one while |SSL_pending| returns zero.
+// For example, |SSL_read| may read a datagram with two records, decrypt the
+// first, and leave the second buffered for a subsequent call to |SSL_read|.
+//
+// As a result, if this function returns one, the next call to |SSL_read| may
+// still fail, read from the transport, or both. The buffered, undecrypted data
+// may be invalid or incomplete.
+OPENSSL_EXPORT int SSL_has_pending(const SSL *ssl);
+
+// SSL_write writes up to |num| bytes from |buf| into |ssl|. It implicitly runs
+// any pending handshakes, including renegotiations when enabled. On success, it
+// returns the number of bytes written. Otherwise, it returns <= 0. The caller
+// should pass the value into |SSL_get_error| to determine how to proceed.
+//
+// In TLS, a non-blocking |SSL_write| differs from non-blocking |write| in that
+// a failed |SSL_write| still commits to the data passed in. When retrying, the
+// caller must supply the original write buffer (or a larger one containing the
+// original as a prefix). By default, retries will fail if they also do not
+// reuse the same |buf| pointer. This may be relaxed with
+// |SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER|, but the buffer contents still must be
+// unchanged.
+//
+// By default, in TLS, |SSL_write| will not return success until all |num| bytes
+// are written. This may be relaxed with |SSL_MODE_ENABLE_PARTIAL_WRITE|. It
+// allows |SSL_write| to complete with a partial result when only part of the
+// input was written in a single record.
+//
+// In DTLS, neither |SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER| and
+// |SSL_MODE_ENABLE_PARTIAL_WRITE| do anything. The caller may retry with a
+// different buffer freely. A single call to |SSL_write| only ever writes a
+// single record in a single packet, so |num| must be at most
+// |SSL3_RT_MAX_PLAIN_LENGTH|.
+//
+// TODO(davidben): Ensure 0 is only returned on transport EOF.
+// https://crbug.com/466303.
+OPENSSL_EXPORT int SSL_write(SSL *ssl, const void *buf, int num);
+
+// SSL_KEY_UPDATE_REQUESTED indicates that the peer should reply to a KeyUpdate
+// message with its own, thus updating traffic secrets for both directions on
+// the connection.
+#define SSL_KEY_UPDATE_REQUESTED 1
+
+// SSL_KEY_UPDATE_NOT_REQUESTED indicates that the peer should not reply with
+// it's own KeyUpdate message.
+#define SSL_KEY_UPDATE_NOT_REQUESTED 0
+
+// SSL_key_update queues a TLS 1.3 KeyUpdate message to be sent on |ssl|
+// if one is not already queued. The |request_type| argument must one of the
+// |SSL_KEY_UPDATE_*| values. This function requires that |ssl| have completed a
+// TLS >= 1.3 handshake. It returns one on success or zero on error.
+//
+// Note that this function does not _send_ the message itself. The next call to
+// |SSL_write| will cause the message to be sent. |SSL_write| may be called with
+// a zero length to flush a KeyUpdate message when no application data is
+// pending.
+OPENSSL_EXPORT int SSL_key_update(SSL *ssl, int request_type);
+
+// SSL_shutdown shuts down |ssl|. It runs in two stages. First, it sends
+// close_notify and returns zero or one on success or -1 on failure. Zero
+// indicates that close_notify was sent, but not received, and one additionally
+// indicates that the peer's close_notify had already been received.
+//
+// To then wait for the peer's close_notify, run |SSL_shutdown| to completion a
+// second time. This returns 1 on success and -1 on failure. Application data
+// is considered a fatal error at this point. To process or discard it, read
+// until close_notify with |SSL_read| instead.
+//
+// In both cases, on failure, pass the return value into |SSL_get_error| to
+// determine how to proceed.
+//
+// Most callers should stop at the first stage. Reading for close_notify is
+// primarily used for uncommon protocols where the underlying transport is
+// reused after TLS completes. Additionally, DTLS uses an unordered transport
+// and is unordered, so the second stage is a no-op in DTLS.
+OPENSSL_EXPORT int SSL_shutdown(SSL *ssl);
+
+// SSL_CTX_set_quiet_shutdown sets quiet shutdown on |ctx| to |mode|. If
+// enabled, |SSL_shutdown| will not send a close_notify alert or wait for one
+// from the peer. It will instead synchronously return one.
+OPENSSL_EXPORT void SSL_CTX_set_quiet_shutdown(SSL_CTX *ctx, int mode);
+
+// SSL_CTX_get_quiet_shutdown returns whether quiet shutdown is enabled for
+// |ctx|.
+OPENSSL_EXPORT int SSL_CTX_get_quiet_shutdown(const SSL_CTX *ctx);
+
+// SSL_set_quiet_shutdown sets quiet shutdown on |ssl| to |mode|. If enabled,
+// |SSL_shutdown| will not send a close_notify alert or wait for one from the
+// peer. It will instead synchronously return one.
+OPENSSL_EXPORT void SSL_set_quiet_shutdown(SSL *ssl, int mode);
+
+// SSL_get_quiet_shutdown returns whether quiet shutdown is enabled for
+// |ssl|.
+OPENSSL_EXPORT int SSL_get_quiet_shutdown(const SSL *ssl);
+
+// SSL_get_error returns a |SSL_ERROR_*| value for the most recent operation on
+// |ssl|. It should be called after an operation failed to determine whether the
+// error was fatal and, if not, when to retry.
+OPENSSL_EXPORT int SSL_get_error(const SSL *ssl, int ret_code);
+
+// SSL_ERROR_NONE indicates the operation succeeded.
+#define SSL_ERROR_NONE 0
+
+// SSL_ERROR_SSL indicates the operation failed within the library. The caller
+// may inspect the error queue for more information.
+#define SSL_ERROR_SSL 1
+
+// SSL_ERROR_WANT_READ indicates the operation failed attempting to read from
+// the transport. The caller may retry the operation when the transport is ready
+// for reading.
+//
+// If signaled by a DTLS handshake, the caller must also call
+// |DTLSv1_get_timeout| and |DTLSv1_handle_timeout| as appropriate. See
+// |SSL_do_handshake|.
+#define SSL_ERROR_WANT_READ 2
+
+// SSL_ERROR_WANT_WRITE indicates the operation failed attempting to write to
+// the transport. The caller may retry the operation when the transport is ready
+// for writing.
+#define SSL_ERROR_WANT_WRITE 3
+
+// SSL_ERROR_WANT_X509_LOOKUP indicates the operation failed in calling the
+// |cert_cb| or |client_cert_cb|. The caller may retry the operation when the
+// callback is ready to return a certificate or one has been configured
+// externally.
+//
+// See also |SSL_CTX_set_cert_cb| and |SSL_CTX_set_client_cert_cb|.
+#define SSL_ERROR_WANT_X509_LOOKUP 4
+
+// SSL_ERROR_SYSCALL indicates the operation failed externally to the library.
+// The caller should consult the system-specific error mechanism. This is
+// typically |errno| but may be something custom if using a custom |BIO|. It
+// may also be signaled if the transport returned EOF, in which case the
+// operation's return value will be zero.
+#define SSL_ERROR_SYSCALL 5
+
+// SSL_ERROR_ZERO_RETURN indicates the operation failed because the connection
+// was cleanly shut down with a close_notify alert.
+#define SSL_ERROR_ZERO_RETURN 6
+
+// SSL_ERROR_WANT_CONNECT indicates the operation failed attempting to connect
+// the transport (the |BIO| signaled |BIO_RR_CONNECT|). The caller may retry the
+// operation when the transport is ready.
+#define SSL_ERROR_WANT_CONNECT 7
+
+// SSL_ERROR_WANT_ACCEPT indicates the operation failed attempting to accept a
+// connection from the transport (the |BIO| signaled |BIO_RR_ACCEPT|). The
+// caller may retry the operation when the transport is ready.
+//
+// TODO(davidben): Remove this. It's used by accept BIOs which are bizarre.
+#define SSL_ERROR_WANT_ACCEPT 8
+
+// SSL_ERROR_WANT_CHANNEL_ID_LOOKUP is never used.
+//
+// TODO(davidben): Remove this. Some callers reference it when stringifying
+// errors. They should use |SSL_error_description| instead.
+#define SSL_ERROR_WANT_CHANNEL_ID_LOOKUP 9
+
+// SSL_ERROR_PENDING_SESSION indicates the operation failed because the session
+// lookup callback indicated the session was unavailable. The caller may retry
+// the operation when lookup has completed.
+//
+// See also |SSL_CTX_sess_set_get_cb| and |SSL_magic_pending_session_ptr|.
+#define SSL_ERROR_PENDING_SESSION 11
+
+// SSL_ERROR_PENDING_CERTIFICATE indicates the operation failed because the
+// early callback indicated certificate lookup was incomplete. The caller may
+// retry the operation when lookup has completed.
+//
+// See also |SSL_CTX_set_select_certificate_cb|.
+#define SSL_ERROR_PENDING_CERTIFICATE 12
+
+// SSL_ERROR_WANT_PRIVATE_KEY_OPERATION indicates the operation failed because
+// a private key operation was unfinished. The caller may retry the operation
+// when the private key operation is complete.
+//
+// See also |SSL_set_private_key_method|, |SSL_CTX_set_private_key_method|, and
+// |SSL_CREDENTIAL_set_private_key_method|.
+#define SSL_ERROR_WANT_PRIVATE_KEY_OPERATION 13
+
+// SSL_ERROR_PENDING_TICKET indicates that a ticket decryption is pending. The
+// caller may retry the operation when the decryption is ready.
+//
+// See also |SSL_CTX_set_ticket_aead_method|.
+#define SSL_ERROR_PENDING_TICKET 14
+
+// SSL_ERROR_EARLY_DATA_REJECTED indicates that early data was rejected. The
+// caller should treat this as a connection failure and retry any operations
+// associated with the rejected early data. |SSL_reset_early_data_reject| may be
+// used to reuse the underlying connection for the retry.
+#define SSL_ERROR_EARLY_DATA_REJECTED 15
+
+// SSL_ERROR_WANT_CERTIFICATE_VERIFY indicates the operation failed because
+// certificate verification was incomplete. The caller may retry the operation
+// when certificate verification is complete.
+//
+// See also |SSL_CTX_set_custom_verify|.
+#define SSL_ERROR_WANT_CERTIFICATE_VERIFY 16
+
+#define SSL_ERROR_HANDOFF 17
+#define SSL_ERROR_HANDBACK 18
+
+// SSL_ERROR_WANT_RENEGOTIATE indicates the operation is pending a response to
+// a renegotiation request from the server. The caller may call
+// |SSL_renegotiate| to schedule a renegotiation and retry the operation.
+//
+// See also |ssl_renegotiate_explicit|.
+#define SSL_ERROR_WANT_RENEGOTIATE 19
+
+// SSL_ERROR_HANDSHAKE_HINTS_READY indicates the handshake has progressed enough
+// for |SSL_serialize_handshake_hints| to be called. See also
+// |SSL_request_handshake_hints|.
+#define SSL_ERROR_HANDSHAKE_HINTS_READY 20
+
+// SSL_error_description returns a string representation of |err|, where |err|
+// is one of the |SSL_ERROR_*| constants returned by |SSL_get_error|, or NULL
+// if the value is unrecognized.
+OPENSSL_EXPORT const char *SSL_error_description(int err);
+
+// SSL_set_mtu sets the |ssl|'s MTU in DTLS to |mtu|. It returns one on success
+// and zero on failure.
+OPENSSL_EXPORT int SSL_set_mtu(SSL *ssl, unsigned mtu);
+
+// DTLSv1_set_initial_timeout_duration sets the initial duration for a DTLS
+// handshake timeout.
+//
+// This duration overrides the default of 1 second, which is the strong
+// recommendation of RFC 6347 (see section 4.2.4.1). However, there may exist
+// situations where a shorter timeout would be beneficial, such as for
+// time-sensitive applications.
+OPENSSL_EXPORT void DTLSv1_set_initial_timeout_duration(SSL *ssl,
+                                                        unsigned duration_ms);
+
+// DTLSv1_get_timeout queries the next DTLS handshake timeout. If there is a
+// timeout in progress, it sets |*out| to the time remaining and returns one.
+// Otherwise, it returns zero.
+//
+// When the timeout expires, call |DTLSv1_handle_timeout| to handle the
+// retransmit behavior.
+//
+// NOTE: This function must be queried again whenever the handshake state
+// machine changes, including when |DTLSv1_handle_timeout| is called.
+OPENSSL_EXPORT int DTLSv1_get_timeout(const SSL *ssl, struct timeval *out);
+
+// DTLSv1_handle_timeout is called when a DTLS handshake timeout expires. If no
+// timeout had expired, it returns 0. Otherwise, it retransmits the previous
+// flight of handshake messages and returns 1. If too many timeouts had expired
+// without progress or an error occurs, it returns -1.
+//
+// The caller's external timer should be compatible with the one |ssl| queries
+// within some fudge factor. Otherwise, the call will be a no-op, but
+// |DTLSv1_get_timeout| will return an updated timeout.
+//
+// If the function returns -1, checking if |SSL_get_error| returns
+// |SSL_ERROR_WANT_WRITE| may be used to determine if the retransmit failed due
+// to a non-fatal error at the write |BIO|. However, the operation may not be
+// retried until the next timeout fires.
+//
+// WARNING: This function breaks the usual return value convention.
+//
+// TODO(davidben): This |SSL_ERROR_WANT_WRITE| behavior is kind of bizarre.
+OPENSSL_EXPORT int DTLSv1_handle_timeout(SSL *ssl);
+
+
+// Protocol versions.
+
+#define DTLS1_VERSION_MAJOR 0xfe
+#define SSL3_VERSION_MAJOR 0x03
+
+#define SSL3_VERSION 0x0300
+#define TLS1_VERSION 0x0301
+#define TLS1_1_VERSION 0x0302
+#define TLS1_2_VERSION 0x0303
+#define TLS1_3_VERSION 0x0304
+
+#define DTLS1_VERSION 0xfeff
+#define DTLS1_2_VERSION 0xfefd
+
+// SSL_CTX_set_min_proto_version sets the minimum protocol version for |ctx| to
+// |version|. If |version| is zero, the default minimum version is used. It
+// returns one on success and zero if |version| is invalid.
+OPENSSL_EXPORT int SSL_CTX_set_min_proto_version(SSL_CTX *ctx,
+                                                 uint16_t version);
+
+// SSL_CTX_set_max_proto_version sets the maximum protocol version for |ctx| to
+// |version|. If |version| is zero, the default maximum version is used. It
+// returns one on success and zero if |version| is invalid.
+OPENSSL_EXPORT int SSL_CTX_set_max_proto_version(SSL_CTX *ctx,
+                                                 uint16_t version);
+
+// SSL_CTX_get_min_proto_version returns the minimum protocol version for |ctx|
+OPENSSL_EXPORT uint16_t SSL_CTX_get_min_proto_version(const SSL_CTX *ctx);
+
+// SSL_CTX_get_max_proto_version returns the maximum protocol version for |ctx|
+OPENSSL_EXPORT uint16_t SSL_CTX_get_max_proto_version(const SSL_CTX *ctx);
+
+// SSL_set_min_proto_version sets the minimum protocol version for |ssl| to
+// |version|. If |version| is zero, the default minimum version is used. It
+// returns one on success and zero if |version| is invalid.
+OPENSSL_EXPORT int SSL_set_min_proto_version(SSL *ssl, uint16_t version);
+
+// SSL_set_max_proto_version sets the maximum protocol version for |ssl| to
+// |version|. If |version| is zero, the default maximum version is used. It
+// returns one on success and zero if |version| is invalid.
+OPENSSL_EXPORT int SSL_set_max_proto_version(SSL *ssl, uint16_t version);
+
+// SSL_get_min_proto_version returns the minimum protocol version for |ssl|. If
+// the connection's configuration has been shed, 0 is returned.
+OPENSSL_EXPORT uint16_t SSL_get_min_proto_version(const SSL *ssl);
+
+// SSL_get_max_proto_version returns the maximum protocol version for |ssl|. If
+// the connection's configuration has been shed, 0 is returned.
+OPENSSL_EXPORT uint16_t SSL_get_max_proto_version(const SSL *ssl);
+
+// SSL_version returns the TLS or DTLS protocol version used by |ssl|, which is
+// one of the |*_VERSION| values. (E.g. |TLS1_2_VERSION|.) Before the version
+// is negotiated, the result is undefined.
+OPENSSL_EXPORT int SSL_version(const SSL *ssl);
+
+
+// Options.
+//
+// Options configure protocol behavior.
+
+// SSL_OP_NO_QUERY_MTU, in DTLS, disables querying the MTU from the underlying
+// |BIO|. Instead, the MTU is configured with |SSL_set_mtu|.
+#define SSL_OP_NO_QUERY_MTU 0x00001000L
+
+// SSL_OP_NO_TICKET disables session ticket support (RFC 5077).
+#define SSL_OP_NO_TICKET 0x00004000L
+
+// SSL_OP_CIPHER_SERVER_PREFERENCE configures servers to select ciphers and
+// ECDHE curves according to the server's preferences instead of the
+// client's.
+#define SSL_OP_CIPHER_SERVER_PREFERENCE 0x00400000L
+
+// The following flags toggle individual protocol versions. This is deprecated.
+// Use |SSL_CTX_set_min_proto_version| and |SSL_CTX_set_max_proto_version|
+// instead.
+#define SSL_OP_NO_TLSv1 0x04000000L
+#define SSL_OP_NO_TLSv1_2 0x08000000L
+#define SSL_OP_NO_TLSv1_1 0x10000000L
+#define SSL_OP_NO_TLSv1_3 0x20000000L
+#define SSL_OP_NO_DTLSv1 SSL_OP_NO_TLSv1
+#define SSL_OP_NO_DTLSv1_2 SSL_OP_NO_TLSv1_2
+
+// SSL_CTX_set_options enables all options set in |options| (which should be one
+// or more of the |SSL_OP_*| values, ORed together) in |ctx|. It returns a
+// bitmask representing the resulting enabled options.
+OPENSSL_EXPORT uint32_t SSL_CTX_set_options(SSL_CTX *ctx, uint32_t options);
+
+// SSL_CTX_clear_options disables all options set in |options| (which should be
+// one or more of the |SSL_OP_*| values, ORed together) in |ctx|. It returns a
+// bitmask representing the resulting enabled options.
+OPENSSL_EXPORT uint32_t SSL_CTX_clear_options(SSL_CTX *ctx, uint32_t options);
+
+// SSL_CTX_get_options returns a bitmask of |SSL_OP_*| values that represent all
+// the options enabled for |ctx|.
+OPENSSL_EXPORT uint32_t SSL_CTX_get_options(const SSL_CTX *ctx);
+
+// SSL_set_options enables all options set in |options| (which should be one or
+// more of the |SSL_OP_*| values, ORed together) in |ssl|. It returns a bitmask
+// representing the resulting enabled options.
+OPENSSL_EXPORT uint32_t SSL_set_options(SSL *ssl, uint32_t options);
+
+// SSL_clear_options disables all options set in |options| (which should be one
+// or more of the |SSL_OP_*| values, ORed together) in |ssl|. It returns a
+// bitmask representing the resulting enabled options.
+OPENSSL_EXPORT uint32_t SSL_clear_options(SSL *ssl, uint32_t options);
+
+// SSL_get_options returns a bitmask of |SSL_OP_*| values that represent all the
+// options enabled for |ssl|.
+OPENSSL_EXPORT uint32_t SSL_get_options(const SSL *ssl);
+
+
+// Modes.
+//
+// Modes configure API behavior.
+
+// SSL_MODE_ENABLE_PARTIAL_WRITE, in TLS, allows |SSL_write| to complete with a
+// partial result when the only part of the input was written in a single
+// record. In DTLS, it does nothing.
+#define SSL_MODE_ENABLE_PARTIAL_WRITE 0x00000001L
+
+// SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER, in TLS, allows retrying an incomplete
+// |SSL_write| with a different buffer. However, |SSL_write| still assumes the
+// buffer contents are unchanged. This is not the default to avoid the
+// misconception that non-blocking |SSL_write| behaves like non-blocking
+// |write|. In DTLS, it does nothing.
+#define SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER 0x00000002L
+
+// SSL_MODE_NO_AUTO_CHAIN disables automatically building a certificate chain
+// before sending certificates to the peer. This flag is set (and the feature
+// disabled) by default.
+// TODO(davidben): Remove this behavior. https://crbug.com/boringssl/42.
+#define SSL_MODE_NO_AUTO_CHAIN 0x00000008L
+
+// SSL_MODE_ENABLE_FALSE_START allows clients to send application data before
+// receipt of ChangeCipherSpec and Finished. This mode enables full handshakes
+// to 'complete' in one RTT. See RFC 7918.
+//
+// When False Start is enabled, |SSL_do_handshake| may succeed before the
+// handshake has completely finished. |SSL_write| will function at this point,
+// and |SSL_read| will transparently wait for the final handshake leg before
+// returning application data. To determine if False Start occurred or when the
+// handshake is completely finished, see |SSL_in_false_start|, |SSL_in_init|,
+// and |SSL_CB_HANDSHAKE_DONE| from |SSL_CTX_set_info_callback|.
+#define SSL_MODE_ENABLE_FALSE_START 0x00000080L
+
+// SSL_MODE_CBC_RECORD_SPLITTING causes multi-byte CBC records in TLS 1.0 to be
+// split in two: the first record will contain a single byte and the second will
+// contain the remainder. This effectively randomises the IV and prevents BEAST
+// attacks.
+#define SSL_MODE_CBC_RECORD_SPLITTING 0x00000100L
+
+// SSL_MODE_NO_SESSION_CREATION will cause any attempts to create a session to
+// fail with SSL_R_SESSION_MAY_NOT_BE_CREATED. This can be used to enforce that
+// session resumption is used for a given SSL*.
+#define SSL_MODE_NO_SESSION_CREATION 0x00000200L
+
+// SSL_MODE_SEND_FALLBACK_SCSV sends TLS_FALLBACK_SCSV in the ClientHello.
+// To be set only by applications that reconnect with a downgraded protocol
+// version; see RFC 7507 for details.
+//
+// DO NOT ENABLE THIS if your application attempts a normal handshake. Only use
+// this in explicit fallback retries, following the guidance in RFC 7507.
+#define SSL_MODE_SEND_FALLBACK_SCSV 0x00000400L
+
+// SSL_CTX_set_mode enables all modes set in |mode| (which should be one or more
+// of the |SSL_MODE_*| values, ORed together) in |ctx|. It returns a bitmask
+// representing the resulting enabled modes.
+OPENSSL_EXPORT uint32_t SSL_CTX_set_mode(SSL_CTX *ctx, uint32_t mode);
+
+// SSL_CTX_clear_mode disables all modes set in |mode| (which should be one or
+// more of the |SSL_MODE_*| values, ORed together) in |ctx|. It returns a
+// bitmask representing the resulting enabled modes.
+OPENSSL_EXPORT uint32_t SSL_CTX_clear_mode(SSL_CTX *ctx, uint32_t mode);
+
+// SSL_CTX_get_mode returns a bitmask of |SSL_MODE_*| values that represent all
+// the modes enabled for |ssl|.
+OPENSSL_EXPORT uint32_t SSL_CTX_get_mode(const SSL_CTX *ctx);
+
+// SSL_set_mode enables all modes set in |mode| (which should be one or more of
+// the |SSL_MODE_*| values, ORed together) in |ssl|. It returns a bitmask
+// representing the resulting enabled modes.
+OPENSSL_EXPORT uint32_t SSL_set_mode(SSL *ssl, uint32_t mode);
+
+// SSL_clear_mode disables all modes set in |mode| (which should be one or more
+// of the |SSL_MODE_*| values, ORed together) in |ssl|. It returns a bitmask
+// representing the resulting enabled modes.
+OPENSSL_EXPORT uint32_t SSL_clear_mode(SSL *ssl, uint32_t mode);
+
+// SSL_get_mode returns a bitmask of |SSL_MODE_*| values that represent all the
+// modes enabled for |ssl|.
+OPENSSL_EXPORT uint32_t SSL_get_mode(const SSL *ssl);
+
+// SSL_CTX_set0_buffer_pool sets a |CRYPTO_BUFFER_POOL| that will be used to
+// store certificates. This can allow multiple connections to share
+// certificates and thus save memory.
+//
+// The SSL_CTX does not take ownership of |pool| and the caller must ensure
+// that |pool| outlives |ctx| and all objects linked to it, including |SSL|,
+// |X509| and |SSL_SESSION| objects. Basically, don't ever free |pool|.
+OPENSSL_EXPORT void SSL_CTX_set0_buffer_pool(SSL_CTX *ctx,
+                                             CRYPTO_BUFFER_POOL *pool);
+
+
+// Credentials.
+//
+// TLS endpoints may present authentication during the handshake, usually using
+// X.509 certificates. This is typically required for servers and optional for
+// clients. BoringSSL uses the |SSL_CREDENTIAL| object to abstract between
+// different kinds of credentials, as well as configure automatic selection
+// between multiple credentials. This may be used to select between ECDSA and
+// RSA certificates.
+//
+// |SSL_CTX| and |SSL| objects maintain lists of credentials in preference
+// order. During the handshake, BoringSSL will select the first usable
+// credential from the list. Non-credential APIs, such as
+// |SSL_CTX_use_certificate|, configure a "default credential", which is
+// appended to this list if configured.
+//
+// When selecting credentials, BoringSSL considers the credential's type, its
+// cryptographic capabilities, and capabilities advertised by the peer. This
+// varies between TLS versions but includes:
+//
+// - Whether the peer supports the leaf certificate key
+// - Whether there is a common signature algorithm that is compatible with the
+//   credential
+// - Whether there is a common cipher suite that is compatible with the
+//   credential
+//
+// WARNING: In TLS 1.2 and below, there is no mechanism for servers to advertise
+// supported ECDSA curves to the client. BoringSSL clients will assume the
+// server accepts all ECDSA curves in client certificates.
+//
+// By default, BoringSSL does not check the following, though we may add APIs
+// in the future to enable them on a per-credential basis.
+//
+// - Whether the peer supports the signature algorithms in the certificate chain
+// - Whether the a server certificate is compatible with the server_name
+//   extension (SNI)
+// - Whether the peer supports the certificate authority that issued the
+//   certificate
+//
+// Credentials may be configured before the handshake or dynamically in the
+// early callback (see |SSL_CTX_set_select_certificate_cb|) and certificate
+// callback (see |SSL_CTX_set_cert_cb|). These callbacks allow applications to
+// use BoringSSL's built-in selection logic in tandem with custom logic. For
+// example, a callback could evaluate application-specific SNI rules to filter
+// down to an ECDSA and RSA credential, then configure both for BoringSSL to
+// select between the two.
+
+// SSL_CREDENTIAL_new_x509 returns a new, empty X.509 credential, or NULL on
+// error. Callers should release the result with |SSL_CREDENTIAL_free| when
+// done.
+//
+// Callers should configure a certificate chain and private key on the
+// credential, along with other properties, then add it with
+// |SSL_CTX_add1_credential|.
+OPENSSL_EXPORT SSL_CREDENTIAL *SSL_CREDENTIAL_new_x509(void);
+
+// SSL_CREDENTIAL_up_ref increments the reference count of |cred|.
+OPENSSL_EXPORT void SSL_CREDENTIAL_up_ref(SSL_CREDENTIAL *cred);
+
+// SSL_CREDENTIAL_free decrements the reference count of |cred|. If it reaches
+// zero, all data referenced by |cred| and |cred| itself are released.
+OPENSSL_EXPORT void SSL_CREDENTIAL_free(SSL_CREDENTIAL *cred);
+
+// SSL_CREDENTIAL_set1_private_key sets |cred|'s private key to |cred|. It
+// returns one on success and zero on failure.
+OPENSSL_EXPORT int SSL_CREDENTIAL_set1_private_key(SSL_CREDENTIAL *cred,
+                                                   EVP_PKEY *key);
+
+// SSL_CREDENTIAL_set1_signing_algorithm_prefs configures |cred| to use |prefs|
+// as the preference list when signing with |cred|'s private key. It returns one
+// on success and zero on error. |prefs| should not include the internal-only
+// value |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
+//
+// It is an error to call this function with delegated credentials (see
+// |SSL_CREDENTIAL_new_delegated|) because delegated credentials already
+// constrain the key to a single algorithm.
+OPENSSL_EXPORT int SSL_CREDENTIAL_set1_signing_algorithm_prefs(
+    SSL_CREDENTIAL *cred, const uint16_t *prefs, size_t num_prefs);
+
+// SSL_CREDENTIAL_set1_cert_chain sets |cred|'s certificate chain, starting from
+// the leaf, to |num_cert|s certificates from |certs|. It returns one on success
+// and zero on error.
+OPENSSL_EXPORT int SSL_CREDENTIAL_set1_cert_chain(SSL_CREDENTIAL *cred,
+                                                  CRYPTO_BUFFER *const *certs,
+                                                  size_t num_certs);
+
+// SSL_CREDENTIAL_set1_ocsp_response sets |cred|'s stapled OCSP response to
+// |ocsp|. It returns one on success and zero on error.
+OPENSSL_EXPORT int SSL_CREDENTIAL_set1_ocsp_response(SSL_CREDENTIAL *cred,
+                                                     CRYPTO_BUFFER *ocsp);
+
+// SSL_CREDENTIAL_set1_signed_cert_timestamp_list sets |cred|'s list of signed
+// certificate timestamps |sct_list|. |sct_list| must contain one or more SCT
+// structures serialised as a SignedCertificateTimestampList (see
+// https://tools.ietf.org/html/rfc6962#section-3.3) – i.e. each SCT is prefixed
+// by a big-endian, uint16 length and the concatenation of one or more such
+// prefixed SCTs are themselves also prefixed by a uint16 length. It returns one
+// on success and zero on error.
+OPENSSL_EXPORT int SSL_CREDENTIAL_set1_signed_cert_timestamp_list(
+    SSL_CREDENTIAL *cred, CRYPTO_BUFFER *sct_list);
+
+// SSL_CTX_add1_credential appends |cred| to |ctx|'s credential list. It returns
+// one on success and zero on error. The credential list is maintained in order
+// of decreasing preference, so earlier calls are preferred over later calls.
+//
+// After calling this function, it is an error to modify |cred|. Doing so may
+// result in inconsistent handshake behavior or race conditions.
+OPENSSL_EXPORT int SSL_CTX_add1_credential(SSL_CTX *ctx, SSL_CREDENTIAL *cred);
+
+// SSL_add1_credential appends |cred| to |ssl|'s credential list. It returns one
+// on success and zero on error. The credential list is maintained in order of
+// decreasing preference, so earlier calls are preferred over later calls.
+//
+// After calling this function, it is an error to modify |cred|. Doing so may
+// result in inconsistent handshake behavior or race conditions.
+OPENSSL_EXPORT int SSL_add1_credential(SSL *ssl, SSL_CREDENTIAL *cred);
+
+// SSL_certs_clear removes all credentials configured on |ssl|. It also removes
+// the certificate chain and private key on the default credential.
+OPENSSL_EXPORT void SSL_certs_clear(SSL *ssl);
+
+// SSL_get0_selected_credential returns the credential in use in the current
+// handshake on |ssl|. If there is current handshake on |ssl| or if the
+// handshake has not progressed to this point, it returns NULL.
+//
+// This function is intended for use with |SSL_CREDENTIAL_get_ex_data|. It may
+// be called from handshake callbacks, such as those in
+// |SSL_PRIVATE_KEY_METHOD|, to trigger credential-specific behavior.
+//
+// In applications that use the older APIs, such as |SSL_use_certificate|, this
+// function may return an internal |SSL_CREDENTIAL| object. This internal object
+// will have no ex_data installed. To avoid this, it is recommended that callers
+// moving to |SSL_CREDENTIAL| use the new APIs consistently.
+OPENSSL_EXPORT const SSL_CREDENTIAL *SSL_get0_selected_credential(
+    const SSL *ssl);
+
+
+// Configuring certificates and private keys.
+//
+// These functions configure the connection's leaf certificate, private key, and
+// certificate chain. The certificate chain is ordered leaf to root (as sent on
+// the wire) but does not include the leaf. Both client and server certificates
+// use these functions.
+//
+// Prefer to configure the certificate before the private key. If configured in
+// the other order, inconsistent private keys will be silently dropped, rather
+// than return an error. Additionally, overwriting a previously-configured
+// certificate and key pair only works if the certificate is configured first.
+//
+// Each of these functions configures the default credential. To select between
+// multiple certificates, see |SSL_CREDENTIAL_new_x509| and related APIs.
+
+// SSL_CTX_use_certificate sets |ctx|'s leaf certificate to |x509|. It returns
+// one on success and zero on failure. If |ctx| has a private key which is
+// inconsistent with |x509|, the private key is silently dropped.
+OPENSSL_EXPORT int SSL_CTX_use_certificate(SSL_CTX *ctx, X509 *x509);
+
+// SSL_use_certificate sets |ssl|'s leaf certificate to |x509|. It returns one
+// on success and zero on failure. If |ssl| has a private key which is
+// inconsistent with |x509|, the private key is silently dropped.
+OPENSSL_EXPORT int SSL_use_certificate(SSL *ssl, X509 *x509);
+
+// SSL_CTX_use_PrivateKey sets |ctx|'s private key to |pkey|. It returns one on
+// success and zero on failure. If |ctx| had a private key or
+// |SSL_PRIVATE_KEY_METHOD| previously configured, it is replaced.
+OPENSSL_EXPORT int SSL_CTX_use_PrivateKey(SSL_CTX *ctx, EVP_PKEY *pkey);
+
+// SSL_use_PrivateKey sets |ssl|'s private key to |pkey|. It returns one on
+// success and zero on failure. If |ssl| had a private key or
+// |SSL_PRIVATE_KEY_METHOD| previously configured, it is replaced.
+OPENSSL_EXPORT int SSL_use_PrivateKey(SSL *ssl, EVP_PKEY *pkey);
+
+// SSL_CTX_set0_chain sets |ctx|'s certificate chain, excluding the leaf, to
+// |chain|. On success, it returns one and takes ownership of |chain|.
+// Otherwise, it returns zero.
+OPENSSL_EXPORT int SSL_CTX_set0_chain(SSL_CTX *ctx, STACK_OF(X509) *chain);
+
+// SSL_CTX_set1_chain sets |ctx|'s certificate chain, excluding the leaf, to
+// |chain|. It returns one on success and zero on failure. The caller retains
+// ownership of |chain| and may release it freely.
+OPENSSL_EXPORT int SSL_CTX_set1_chain(SSL_CTX *ctx, STACK_OF(X509) *chain);
+
+// SSL_set0_chain sets |ssl|'s certificate chain, excluding the leaf, to
+// |chain|. On success, it returns one and takes ownership of |chain|.
+// Otherwise, it returns zero.
+OPENSSL_EXPORT int SSL_set0_chain(SSL *ssl, STACK_OF(X509) *chain);
+
+// SSL_set1_chain sets |ssl|'s certificate chain, excluding the leaf, to
+// |chain|. It returns one on success and zero on failure. The caller retains
+// ownership of |chain| and may release it freely.
+OPENSSL_EXPORT int SSL_set1_chain(SSL *ssl, STACK_OF(X509) *chain);
+
+// SSL_CTX_add0_chain_cert appends |x509| to |ctx|'s certificate chain. On
+// success, it returns one and takes ownership of |x509|. Otherwise, it returns
+// zero.
+OPENSSL_EXPORT int SSL_CTX_add0_chain_cert(SSL_CTX *ctx, X509 *x509);
+
+// SSL_CTX_add1_chain_cert appends |x509| to |ctx|'s certificate chain. It
+// returns one on success and zero on failure. The caller retains ownership of
+// |x509| and may release it freely.
+OPENSSL_EXPORT int SSL_CTX_add1_chain_cert(SSL_CTX *ctx, X509 *x509);
+
+// SSL_add0_chain_cert appends |x509| to |ctx|'s certificate chain. On success,
+// it returns one and takes ownership of |x509|. Otherwise, it returns zero.
+OPENSSL_EXPORT int SSL_add0_chain_cert(SSL *ssl, X509 *x509);
+
+// SSL_CTX_add_extra_chain_cert calls |SSL_CTX_add0_chain_cert|.
+OPENSSL_EXPORT int SSL_CTX_add_extra_chain_cert(SSL_CTX *ctx, X509 *x509);
+
+// SSL_add1_chain_cert appends |x509| to |ctx|'s certificate chain. It returns
+// one on success and zero on failure. The caller retains ownership of |x509|
+// and may release it freely.
+OPENSSL_EXPORT int SSL_add1_chain_cert(SSL *ssl, X509 *x509);
+
+// SSL_CTX_clear_chain_certs clears |ctx|'s certificate chain and returns
+// one.
+OPENSSL_EXPORT int SSL_CTX_clear_chain_certs(SSL_CTX *ctx);
+
+// SSL_CTX_clear_extra_chain_certs calls |SSL_CTX_clear_chain_certs|.
+OPENSSL_EXPORT int SSL_CTX_clear_extra_chain_certs(SSL_CTX *ctx);
+
+// SSL_clear_chain_certs clears |ssl|'s certificate chain and returns one.
+OPENSSL_EXPORT int SSL_clear_chain_certs(SSL *ssl);
+
+// SSL_CTX_set_cert_cb sets a callback that is called to select a certificate.
+// The callback returns one on success, zero on internal error, and a negative
+// number on failure or to pause the handshake. If the handshake is paused,
+// |SSL_get_error| will return |SSL_ERROR_WANT_X509_LOOKUP|.
+//
+// On the client, the callback may call |SSL_get0_certificate_types| and
+// |SSL_get_client_CA_list| for information on the server's certificate
+// request.
+//
+// On the server, the callback will be called after extensions have been
+// processed, but before the resumption decision has been made. This differs
+// from OpenSSL which handles resumption before selecting the certificate.
+OPENSSL_EXPORT void SSL_CTX_set_cert_cb(SSL_CTX *ctx,
+                                        int (*cb)(SSL *ssl, void *arg),
+                                        void *arg);
+
+// SSL_set_cert_cb sets a callback that is called to select a certificate. The
+// callback returns one on success, zero on internal error, and a negative
+// number on failure or to pause the handshake. If the handshake is paused,
+// |SSL_get_error| will return |SSL_ERROR_WANT_X509_LOOKUP|.
+//
+// On the client, the callback may call |SSL_get0_certificate_types| and
+// |SSL_get_client_CA_list| for information on the server's certificate
+// request.
+//
+// On the server, the callback will be called after extensions have been
+// processed, but before the resumption decision has been made. This differs
+// from OpenSSL which handles resumption before selecting the certificate.
+OPENSSL_EXPORT void SSL_set_cert_cb(SSL *ssl, int (*cb)(SSL *ssl, void *arg),
+                                    void *arg);
+
+// SSL_get0_certificate_types, for a client, sets |*out_types| to an array
+// containing the client certificate types requested by a server. It returns the
+// length of the array. Note this list is always empty in TLS 1.3. The server
+// will instead send signature algorithms. See
+// |SSL_get0_peer_verify_algorithms|.
+//
+// The behavior of this function is undefined except during the callbacks set by
+// by |SSL_CTX_set_cert_cb| and |SSL_CTX_set_client_cert_cb| or when the
+// handshake is paused because of them.
+OPENSSL_EXPORT size_t SSL_get0_certificate_types(const SSL *ssl,
+                                                 const uint8_t **out_types);
+
+// SSL_get0_peer_verify_algorithms sets |*out_sigalgs| to an array containing
+// the signature algorithms the peer is able to verify. It returns the length of
+// the array. Note these values are only sent starting TLS 1.2 and only
+// mandatory starting TLS 1.3. If not sent, the empty array is returned. For the
+// historical client certificate types list, see |SSL_get0_certificate_types|.
+//
+// The behavior of this function is undefined except during the callbacks set by
+// by |SSL_CTX_set_cert_cb| and |SSL_CTX_set_client_cert_cb| or when the
+// handshake is paused because of them.
+OPENSSL_EXPORT size_t
+SSL_get0_peer_verify_algorithms(const SSL *ssl, const uint16_t **out_sigalgs);
+
+// SSL_get0_peer_delegation_algorithms sets |*out_sigalgs| to an array
+// containing the signature algorithms the peer is willing to use with delegated
+// credentials.  It returns the length of the array. If not sent, the empty
+// array is returned.
+//
+// The behavior of this function is undefined except during the callbacks set by
+// by |SSL_CTX_set_cert_cb| and |SSL_CTX_set_client_cert_cb| or when the
+// handshake is paused because of them.
+OPENSSL_EXPORT size_t
+SSL_get0_peer_delegation_algorithms(const SSL *ssl,
+                                    const uint16_t **out_sigalgs);
+
+// SSL_CTX_get0_certificate returns |ctx|'s leaf certificate.
+OPENSSL_EXPORT X509 *SSL_CTX_get0_certificate(const SSL_CTX *ctx);
+
+// SSL_get_certificate returns |ssl|'s leaf certificate.
+OPENSSL_EXPORT X509 *SSL_get_certificate(const SSL *ssl);
+
+// SSL_CTX_get0_privatekey returns |ctx|'s private key.
+OPENSSL_EXPORT EVP_PKEY *SSL_CTX_get0_privatekey(const SSL_CTX *ctx);
+
+// SSL_get_privatekey returns |ssl|'s private key.
+OPENSSL_EXPORT EVP_PKEY *SSL_get_privatekey(const SSL *ssl);
+
+// SSL_CTX_get0_chain_certs sets |*out_chain| to |ctx|'s certificate chain and
+// returns one.
+OPENSSL_EXPORT int SSL_CTX_get0_chain_certs(const SSL_CTX *ctx,
+                                            STACK_OF(X509) **out_chain);
+
+// SSL_CTX_get_extra_chain_certs calls |SSL_CTX_get0_chain_certs|.
+OPENSSL_EXPORT int SSL_CTX_get_extra_chain_certs(const SSL_CTX *ctx,
+                                                 STACK_OF(X509) **out_chain);
+
+// SSL_get0_chain_certs sets |*out_chain| to |ssl|'s certificate chain and
+// returns one.
+OPENSSL_EXPORT int SSL_get0_chain_certs(const SSL *ssl,
+                                        STACK_OF(X509) **out_chain);
+
+// SSL_CTX_set_signed_cert_timestamp_list sets the list of signed certificate
+// timestamps that is sent to clients that request it. The |list| argument must
+// contain one or more SCT structures serialised as a SignedCertificateTimestamp
+// List (see https://tools.ietf.org/html/rfc6962#section-3.3) – i.e. each SCT
+// is prefixed by a big-endian, uint16 length and the concatenation of one or
+// more such prefixed SCTs are themselves also prefixed by a uint16 length. It
+// returns one on success and zero on error. The caller retains ownership of
+// |list|.
+OPENSSL_EXPORT int SSL_CTX_set_signed_cert_timestamp_list(SSL_CTX *ctx,
+                                                          const uint8_t *list,
+                                                          size_t list_len);
+
+// SSL_set_signed_cert_timestamp_list sets the list of signed certificate
+// timestamps that is sent to clients that request is. The same format as the
+// one used for |SSL_CTX_set_signed_cert_timestamp_list| applies. The caller
+// retains ownership of |list|.
+OPENSSL_EXPORT int SSL_set_signed_cert_timestamp_list(SSL *ctx,
+                                                      const uint8_t *list,
+                                                      size_t list_len);
+
+// SSL_CTX_set_ocsp_response sets the OCSP response that is sent to clients
+// which request it. It returns one on success and zero on error. The caller
+// retains ownership of |response|.
+OPENSSL_EXPORT int SSL_CTX_set_ocsp_response(SSL_CTX *ctx,
+                                             const uint8_t *response,
+                                             size_t response_len);
+
+// SSL_set_ocsp_response sets the OCSP response that is sent to clients which
+// request it. It returns one on success and zero on error. The caller retains
+// ownership of |response|.
+OPENSSL_EXPORT int SSL_set_ocsp_response(SSL *ssl,
+                                         const uint8_t *response,
+                                         size_t response_len);
+
+// SSL_SIGN_* are signature algorithm values as defined in TLS 1.3.
+#define SSL_SIGN_RSA_PKCS1_SHA1 0x0201
+#define SSL_SIGN_RSA_PKCS1_SHA256 0x0401
+#define SSL_SIGN_RSA_PKCS1_SHA384 0x0501
+#define SSL_SIGN_RSA_PKCS1_SHA512 0x0601
+#define SSL_SIGN_ECDSA_SHA1 0x0203
+#define SSL_SIGN_ECDSA_SECP256R1_SHA256 0x0403
+#define SSL_SIGN_ECDSA_SECP384R1_SHA384 0x0503
+#define SSL_SIGN_ECDSA_SECP521R1_SHA512 0x0603
+#define SSL_SIGN_RSA_PSS_RSAE_SHA256 0x0804
+#define SSL_SIGN_RSA_PSS_RSAE_SHA384 0x0805
+#define SSL_SIGN_RSA_PSS_RSAE_SHA512 0x0806
+#define SSL_SIGN_ED25519 0x0807
+
+// SSL_SIGN_RSA_PKCS1_MD5_SHA1 is an internal signature algorithm used to
+// specify raw RSASSA-PKCS1-v1_5 with an MD5/SHA-1 concatenation, as used in TLS
+// before TLS 1.2.
+#define SSL_SIGN_RSA_PKCS1_MD5_SHA1 0xff01
+
+// SSL_get_signature_algorithm_name returns a human-readable name for |sigalg|,
+// or NULL if unknown. If |include_curve| is one, the curve for ECDSA algorithms
+// is included as in TLS 1.3. Otherwise, it is excluded as in TLS 1.2.
+OPENSSL_EXPORT const char *SSL_get_signature_algorithm_name(uint16_t sigalg,
+                                                            int include_curve);
+
+// SSL_get_all_signature_algorithm_names outputs a list of possible strings
+// |SSL_get_signature_algorithm_name| may return in this version of BoringSSL.
+// It writes at most |max_out| entries to |out| and returns the total number it
+// would have written, if |max_out| had been large enough. |max_out| may be
+// initially set to zero to size the output.
+//
+// This function is only intended to help initialize tables in callers that want
+// possible strings pre-declared. This list would not be suitable to set a list
+// of supported features. It is in no particular order, and may contain
+// placeholder, experimental, or deprecated values that do not apply to every
+// caller. Future versions of BoringSSL may also return strings not in this
+// list, so this does not apply if, say, sending strings across services.
+OPENSSL_EXPORT size_t SSL_get_all_signature_algorithm_names(const char **out,
+                                                            size_t max_out);
+
+// SSL_get_signature_algorithm_key_type returns the key type associated with
+// |sigalg| as an |EVP_PKEY_*| constant or |EVP_PKEY_NONE| if unknown.
+OPENSSL_EXPORT int SSL_get_signature_algorithm_key_type(uint16_t sigalg);
+
+// SSL_get_signature_algorithm_digest returns the digest function associated
+// with |sigalg| or |NULL| if |sigalg| has no prehash (Ed25519) or is unknown.
+OPENSSL_EXPORT const EVP_MD *SSL_get_signature_algorithm_digest(
+    uint16_t sigalg);
+
+// SSL_is_signature_algorithm_rsa_pss returns one if |sigalg| is an RSA-PSS
+// signature algorithm and zero otherwise.
+OPENSSL_EXPORT int SSL_is_signature_algorithm_rsa_pss(uint16_t sigalg);
+
+// SSL_CTX_set_signing_algorithm_prefs configures |ctx| to use |prefs| as the
+// preference list when signing with |ctx|'s private key. It returns one on
+// success and zero on error. |prefs| should not include the internal-only value
+// |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
+OPENSSL_EXPORT int SSL_CTX_set_signing_algorithm_prefs(SSL_CTX *ctx,
+                                                       const uint16_t *prefs,
+                                                       size_t num_prefs);
+
+// SSL_set_signing_algorithm_prefs configures |ssl| to use |prefs| as the
+// preference list when signing with |ssl|'s private key. It returns one on
+// success and zero on error. |prefs| should not include the internal-only value
+// |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
+OPENSSL_EXPORT int SSL_set_signing_algorithm_prefs(SSL *ssl,
+                                                   const uint16_t *prefs,
+                                                   size_t num_prefs);
+
+
+// Certificate and private key convenience functions.
+
+// SSL_CTX_set_chain_and_key sets the certificate chain and private key for a
+// TLS client or server. References to the given |CRYPTO_BUFFER| and |EVP_PKEY|
+// objects are added as needed. Exactly one of |privkey| or |privkey_method|
+// may be non-NULL. Returns one on success and zero on error.
+OPENSSL_EXPORT int SSL_CTX_set_chain_and_key(
+    SSL_CTX *ctx, CRYPTO_BUFFER *const *certs, size_t num_certs,
+    EVP_PKEY *privkey, const SSL_PRIVATE_KEY_METHOD *privkey_method);
+
+// SSL_set_chain_and_key sets the certificate chain and private key for a TLS
+// client or server. References to the given |CRYPTO_BUFFER| and |EVP_PKEY|
+// objects are added as needed. Exactly one of |privkey| or |privkey_method|
+// may be non-NULL. Returns one on success and zero on error.
+OPENSSL_EXPORT int SSL_set_chain_and_key(
+    SSL *ssl, CRYPTO_BUFFER *const *certs, size_t num_certs, EVP_PKEY *privkey,
+    const SSL_PRIVATE_KEY_METHOD *privkey_method);
+
+// SSL_CTX_get0_chain returns the list of |CRYPTO_BUFFER|s that were set by
+// |SSL_CTX_set_chain_and_key|. Reference counts are not incremented by this
+// call. The return value may be |NULL| if no chain has been set.
+//
+// (Note: if a chain was configured by non-|CRYPTO_BUFFER|-based functions then
+// the return value is undefined and, even if not NULL, the stack itself may
+// contain nullptrs. Thus you shouldn't mix this function with
+// non-|CRYPTO_BUFFER| functions for manipulating the chain.)
+OPENSSL_EXPORT const STACK_OF(CRYPTO_BUFFER) *SSL_CTX_get0_chain(
+    const SSL_CTX *ctx);
+
+// SSL_get0_chain returns the list of |CRYPTO_BUFFER|s that were set by
+// |SSL_set_chain_and_key|, unless they have been discarded. Reference counts
+// are not incremented by this call. The return value may be |NULL| if no chain
+// has been set.
+//
+// (Note: if a chain was configured by non-|CRYPTO_BUFFER|-based functions then
+// the return value is undefined and, even if not NULL, the stack itself may
+// contain nullptrs. Thus you shouldn't mix this function with
+// non-|CRYPTO_BUFFER| functions for manipulating the chain.)
+//
+// This function may return nullptr if a handshake has completed even if
+// |SSL_set_chain_and_key| was previously called, since the configuration
+// containing the certificates is typically cleared after handshake completion.
+OPENSSL_EXPORT const STACK_OF(CRYPTO_BUFFER) *SSL_get0_chain(const SSL *ssl);
+
+// SSL_CTX_use_RSAPrivateKey sets |ctx|'s private key to |rsa|. It returns one
+// on success and zero on failure.
+OPENSSL_EXPORT int SSL_CTX_use_RSAPrivateKey(SSL_CTX *ctx, RSA *rsa);
+
+// SSL_use_RSAPrivateKey sets |ctx|'s private key to |rsa|. It returns one on
+// success and zero on failure.
+OPENSSL_EXPORT int SSL_use_RSAPrivateKey(SSL *ssl, RSA *rsa);
+
+// The following functions configure certificates or private keys but take as
+// input DER-encoded structures. They return one on success and zero on
+// failure.
+
+OPENSSL_EXPORT int SSL_CTX_use_certificate_ASN1(SSL_CTX *ctx, size_t der_len,
+                                                const uint8_t *der);
+OPENSSL_EXPORT int SSL_use_certificate_ASN1(SSL *ssl, const uint8_t *der,
+                                            size_t der_len);
+
+OPENSSL_EXPORT int SSL_CTX_use_PrivateKey_ASN1(int pk, SSL_CTX *ctx,
+                                               const uint8_t *der,
+                                               size_t der_len);
+OPENSSL_EXPORT int SSL_use_PrivateKey_ASN1(int type, SSL *ssl,
+                                           const uint8_t *der, size_t der_len);
+
+OPENSSL_EXPORT int SSL_CTX_use_RSAPrivateKey_ASN1(SSL_CTX *ctx,
+                                                  const uint8_t *der,
+                                                  size_t der_len);
+OPENSSL_EXPORT int SSL_use_RSAPrivateKey_ASN1(SSL *ssl, const uint8_t *der,
+                                              size_t der_len);
+
+// The following functions configure certificates or private keys but take as
+// input files to read from. They return one on success and zero on failure. The
+// |type| parameter is one of the |SSL_FILETYPE_*| values and determines whether
+// the file's contents are read as PEM or DER.
+
+#define SSL_FILETYPE_PEM 1
+#define SSL_FILETYPE_ASN1 2
+
+OPENSSL_EXPORT int SSL_CTX_use_RSAPrivateKey_file(SSL_CTX *ctx,
+                                                  const char *file,
+                                                  int type);
+OPENSSL_EXPORT int SSL_use_RSAPrivateKey_file(SSL *ssl, const char *file,
+                                              int type);
+
+OPENSSL_EXPORT int SSL_CTX_use_certificate_file(SSL_CTX *ctx, const char *file,
+                                                int type);
+OPENSSL_EXPORT int SSL_use_certificate_file(SSL *ssl, const char *file,
+                                            int type);
+
+OPENSSL_EXPORT int SSL_CTX_use_PrivateKey_file(SSL_CTX *ctx, const char *file,
+                                               int type);
+OPENSSL_EXPORT int SSL_use_PrivateKey_file(SSL *ssl, const char *file,
+                                           int type);
+
+// SSL_CTX_use_certificate_chain_file configures certificates for |ctx|. It
+// reads the contents of |file| as a PEM-encoded leaf certificate followed
+// optionally by the certificate chain to send to the peer. It returns one on
+// success and zero on failure.
+//
+// WARNING: If the input contains "TRUSTED CERTIFICATE" PEM blocks, this
+// function parses auxiliary properties as in |d2i_X509_AUX|. Passing untrusted
+// input to this function allows an attacker to influence those properties. See
+// |d2i_X509_AUX| for details.
+OPENSSL_EXPORT int SSL_CTX_use_certificate_chain_file(SSL_CTX *ctx,
+                                                      const char *file);
+
+// SSL_CTX_set_default_passwd_cb sets the password callback for PEM-based
+// convenience functions called on |ctx|.
+OPENSSL_EXPORT void SSL_CTX_set_default_passwd_cb(SSL_CTX *ctx,
+                                                  pem_password_cb *cb);
+
+// SSL_CTX_get_default_passwd_cb returns the callback set by
+// |SSL_CTX_set_default_passwd_cb|.
+OPENSSL_EXPORT pem_password_cb *SSL_CTX_get_default_passwd_cb(
+    const SSL_CTX *ctx);
+
+// SSL_CTX_set_default_passwd_cb_userdata sets the userdata parameter for
+// |ctx|'s password callback.
+OPENSSL_EXPORT void SSL_CTX_set_default_passwd_cb_userdata(SSL_CTX *ctx,
+                                                           void *data);
+
+// SSL_CTX_get_default_passwd_cb_userdata returns the userdata parameter set by
+// |SSL_CTX_set_default_passwd_cb_userdata|.
+OPENSSL_EXPORT void *SSL_CTX_get_default_passwd_cb_userdata(const SSL_CTX *ctx);
+
+
+// Custom private keys.
+
+enum ssl_private_key_result_t BORINGSSL_ENUM_INT {
+  ssl_private_key_success,
+  ssl_private_key_retry,
+  ssl_private_key_failure,
+};
+
+// ssl_private_key_method_st (aka |SSL_PRIVATE_KEY_METHOD|) describes private
+// key hooks. This is used to off-load signing operations to a custom,
+// potentially asynchronous, backend. Metadata about the key such as the type
+// and size are parsed out of the certificate.
+struct ssl_private_key_method_st {
+  // sign signs the message |in| in using the specified signature algorithm. On
+  // success, it returns |ssl_private_key_success| and writes at most |max_out|
+  // bytes of signature data to |out| and sets |*out_len| to the number of bytes
+  // written. On failure, it returns |ssl_private_key_failure|. If the operation
+  // has not completed, it returns |ssl_private_key_retry|. |sign| should
+  // arrange for the high-level operation on |ssl| to be retried when the
+  // operation is completed. This will result in a call to |complete|.
+  //
+  // |signature_algorithm| is one of the |SSL_SIGN_*| values, as defined in TLS
+  // 1.3. Note that, in TLS 1.2, ECDSA algorithms do not require that curve
+  // sizes match hash sizes, so the curve portion of |SSL_SIGN_ECDSA_*| values
+  // must be ignored. BoringSSL will internally handle the curve matching logic
+  // where appropriate.
+  //
+  // It is an error to call |sign| while another private key operation is in
+  // progress on |ssl|.
+  enum ssl_private_key_result_t (*sign)(SSL *ssl, uint8_t *out, size_t *out_len,
+                                        size_t max_out,
+                                        uint16_t signature_algorithm,
+                                        const uint8_t *in, size_t in_len);
+
+  // decrypt decrypts |in_len| bytes of encrypted data from |in|. On success it
+  // returns |ssl_private_key_success|, writes at most |max_out| bytes of
+  // decrypted data to |out| and sets |*out_len| to the actual number of bytes
+  // written. On failure it returns |ssl_private_key_failure|. If the operation
+  // has not completed, it returns |ssl_private_key_retry|. The caller should
+  // arrange for the high-level operation on |ssl| to be retried when the
+  // operation is completed, which will result in a call to |complete|. This
+  // function only works with RSA keys and should perform a raw RSA decryption
+  // operation with no padding.
+  //
+  // It is an error to call |decrypt| while another private key operation is in
+  // progress on |ssl|.
+  enum ssl_private_key_result_t (*decrypt)(SSL *ssl, uint8_t *out,
+                                           size_t *out_len, size_t max_out,
+                                           const uint8_t *in, size_t in_len);
+
+  // complete completes a pending operation. If the operation has completed, it
+  // returns |ssl_private_key_success| and writes the result to |out| as in
+  // |sign|. Otherwise, it returns |ssl_private_key_failure| on failure and
+  // |ssl_private_key_retry| if the operation is still in progress.
+  //
+  // |complete| may be called arbitrarily many times before completion, but it
+  // is an error to call |complete| if there is no pending operation in progress
+  // on |ssl|.
+  enum ssl_private_key_result_t (*complete)(SSL *ssl, uint8_t *out,
+                                            size_t *out_len, size_t max_out);
+};
+
+// SSL_set_private_key_method configures a custom private key on |ssl|.
+// |key_method| must remain valid for the lifetime of |ssl|.
+//
+// If using an RSA or ECDSA key, callers should configure signing capabilities
+// with |SSL_set_signing_algorithm_prefs|. Otherwise, BoringSSL may select a
+// signature algorithm that |key_method| does not support.
+OPENSSL_EXPORT void SSL_set_private_key_method(
+    SSL *ssl, const SSL_PRIVATE_KEY_METHOD *key_method);
+
+// SSL_CTX_set_private_key_method configures a custom private key on |ctx|.
+// |key_method| must remain valid for the lifetime of |ctx|.
+//
+// If using an RSA or ECDSA key, callers should configure signing capabilities
+// with |SSL_CTX_set_signing_algorithm_prefs|. Otherwise, BoringSSL may select a
+// signature algorithm that |key_method| does not support.
+OPENSSL_EXPORT void SSL_CTX_set_private_key_method(
+    SSL_CTX *ctx, const SSL_PRIVATE_KEY_METHOD *key_method);
+
+// SSL_CREDENTIAL_set_private_key_method configures a custom private key on
+// |cred|. |key_method| must remain valid for the lifetime of |cred|. It returns
+// one on success and zero if |cred| does not use private keys.
+//
+// If using an RSA or ECDSA key, callers should configure signing capabilities
+// with |SSL_CREDENTIAL_set1_signing_algorithm_prefs|. Otherwise, BoringSSL may
+// select a signature algorithm that |key_method| does not support. This is not
+// necessary for delegated credentials (see |SSL_CREDENTIAL_new_delegated|)
+// because delegated credentials only support a single signature algorithm.
+//
+// Functions in |key_method| will be passed an |SSL| object, but not |cred|
+// directly. Use |SSL_get0_selected_credential| to determine the selected
+// credential. From there, |SSL_CREDENTIAL_get_ex_data| can be used to look up
+// credential-specific state, such as a handle to the private key.
+OPENSSL_EXPORT int SSL_CREDENTIAL_set_private_key_method(
+    SSL_CREDENTIAL *cred, const SSL_PRIVATE_KEY_METHOD *key_method);
+
+// SSL_can_release_private_key returns one if |ssl| will no longer call into the
+// private key and zero otherwise. If the function returns one, the caller can
+// release state associated with the private key.
+//
+// NOTE: This function assumes the caller does not use |SSL_clear| to reuse
+// |ssl| for a second connection. If |SSL_clear| is used, BoringSSL may still
+// use the private key on the second connection.
+OPENSSL_EXPORT int SSL_can_release_private_key(const SSL *ssl);
+
+
+// Cipher suites.
+//
+// |SSL_CIPHER| objects represent cipher suites.
+
+DEFINE_CONST_STACK_OF(SSL_CIPHER)
+
+// SSL_get_cipher_by_value returns the structure representing a TLS cipher
+// suite based on its assigned number, or NULL if unknown. See
+// https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#tls-parameters-4.
+OPENSSL_EXPORT const SSL_CIPHER *SSL_get_cipher_by_value(uint16_t value);
+
+// SSL_CIPHER_get_id returns |cipher|'s non-IANA id. This is not its
+// IANA-assigned number, which is called the "value" here, although it may be
+// cast to a |uint16_t| to get it.
+OPENSSL_EXPORT uint32_t SSL_CIPHER_get_id(const SSL_CIPHER *cipher);
+
+// SSL_CIPHER_get_protocol_id returns |cipher|'s IANA-assigned number.
+OPENSSL_EXPORT uint16_t SSL_CIPHER_get_protocol_id(const SSL_CIPHER *cipher);
+
+// SSL_CIPHER_is_aead returns one if |cipher| uses an AEAD cipher.
+OPENSSL_EXPORT int SSL_CIPHER_is_aead(const SSL_CIPHER *cipher);
+
+// SSL_CIPHER_is_block_cipher returns one if |cipher| is a block cipher.
+OPENSSL_EXPORT int SSL_CIPHER_is_block_cipher(const SSL_CIPHER *cipher);
+
+// SSL_CIPHER_get_cipher_nid returns the NID for |cipher|'s bulk
+// cipher. Possible values are |NID_aes_128_gcm|, |NID_aes_256_gcm|,
+// |NID_chacha20_poly1305|, |NID_aes_128_cbc|, |NID_aes_256_cbc|, and
+// |NID_des_ede3_cbc|.
+OPENSSL_EXPORT int SSL_CIPHER_get_cipher_nid(const SSL_CIPHER *cipher);
+
+// SSL_CIPHER_get_digest_nid returns the NID for |cipher|'s HMAC if it is a
+// legacy cipher suite. For modern AEAD-based ciphers (see
+// |SSL_CIPHER_is_aead|), it returns |NID_undef|.
+//
+// Note this function only returns the legacy HMAC digest, not the PRF hash.
+OPENSSL_EXPORT int SSL_CIPHER_get_digest_nid(const SSL_CIPHER *cipher);
+
+// SSL_CIPHER_get_kx_nid returns the NID for |cipher|'s key exchange. This may
+// be |NID_kx_rsa|, |NID_kx_ecdhe|, or |NID_kx_psk| for TLS 1.2. In TLS 1.3,
+// cipher suites do not specify the key exchange, so this function returns
+// |NID_kx_any|.
+OPENSSL_EXPORT int SSL_CIPHER_get_kx_nid(const SSL_CIPHER *cipher);
+
+// SSL_CIPHER_get_auth_nid returns the NID for |cipher|'s authentication
+// type. This may be |NID_auth_rsa|, |NID_auth_ecdsa|, or |NID_auth_psk| for TLS
+// 1.2. In TLS 1.3, cipher suites do not specify authentication, so this
+// function returns |NID_auth_any|.
+OPENSSL_EXPORT int SSL_CIPHER_get_auth_nid(const SSL_CIPHER *cipher);
+
+// SSL_CIPHER_get_handshake_digest returns |cipher|'s PRF hash. If |cipher|
+// is a pre-TLS-1.2 cipher, it returns |EVP_md5_sha1| but note these ciphers use
+// SHA-256 in TLS 1.2. Other return values may be treated uniformly in all
+// applicable versions.
+OPENSSL_EXPORT const EVP_MD *SSL_CIPHER_get_handshake_digest(
+    const SSL_CIPHER *cipher);
+
+// SSL_CIPHER_get_prf_nid behaves like |SSL_CIPHER_get_handshake_digest| but
+// returns the NID constant. Use |SSL_CIPHER_get_handshake_digest| instead.
+OPENSSL_EXPORT int SSL_CIPHER_get_prf_nid(const SSL_CIPHER *cipher);
+
+// SSL_CIPHER_get_min_version returns the minimum protocol version required
+// for |cipher|.
+OPENSSL_EXPORT uint16_t SSL_CIPHER_get_min_version(const SSL_CIPHER *cipher);
+
+// SSL_CIPHER_get_max_version returns the maximum protocol version that
+// supports |cipher|.
+OPENSSL_EXPORT uint16_t SSL_CIPHER_get_max_version(const SSL_CIPHER *cipher);
+
+// SSL_CIPHER_standard_name returns the standard IETF name for |cipher|. For
+// example, "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256".
+OPENSSL_EXPORT const char *SSL_CIPHER_standard_name(const SSL_CIPHER *cipher);
+
+// SSL_CIPHER_get_name returns the OpenSSL name of |cipher|. For example,
+// "ECDHE-RSA-AES128-GCM-SHA256". Callers are recommended to use
+// |SSL_CIPHER_standard_name| instead.
+OPENSSL_EXPORT const char *SSL_CIPHER_get_name(const SSL_CIPHER *cipher);
+
+// SSL_CIPHER_get_kx_name returns a string that describes the key-exchange
+// method used by |cipher|. For example, "ECDHE_ECDSA". TLS 1.3 AEAD-only
+// ciphers return the string "GENERIC".
+OPENSSL_EXPORT const char *SSL_CIPHER_get_kx_name(const SSL_CIPHER *cipher);
+
+// SSL_CIPHER_get_bits returns the strength, in bits, of |cipher|. If
+// |out_alg_bits| is not NULL, it writes the number of bits consumed by the
+// symmetric algorithm to |*out_alg_bits|.
+OPENSSL_EXPORT int SSL_CIPHER_get_bits(const SSL_CIPHER *cipher,
+                                       int *out_alg_bits);
+
+// SSL_get_all_cipher_names outputs a list of possible strings
+// |SSL_CIPHER_get_name| may return in this version of BoringSSL. It writes at
+// most |max_out| entries to |out| and returns the total number it would have
+// written, if |max_out| had been large enough. |max_out| may be initially set
+// to zero to size the output.
+//
+// This function is only intended to help initialize tables in callers that want
+// possible strings pre-declared. This list would not be suitable to set a list
+// of supported features. It is in no particular order, and may contain
+// placeholder, experimental, or deprecated values that do not apply to every
+// caller. Future versions of BoringSSL may also return strings not in this
+// list, so this does not apply if, say, sending strings across services.
+OPENSSL_EXPORT size_t SSL_get_all_cipher_names(const char **out,
+                                               size_t max_out);
+
+
+// SSL_get_all_standard_cipher_names outputs a list of possible strings
+// |SSL_CIPHER_standard_name| may return in this version of BoringSSL. It writes
+// at most |max_out| entries to |out| and returns the total number it would have
+// written, if |max_out| had been large enough. |max_out| may be initially set
+// to zero to size the output.
+//
+// This function is only intended to help initialize tables in callers that want
+// possible strings pre-declared. This list would not be suitable to set a list
+// of supported features. It is in no particular order, and may contain
+// placeholder, experimental, or deprecated values that do not apply to every
+// caller. Future versions of BoringSSL may also return strings not in this
+// list, so this does not apply if, say, sending strings across services.
+OPENSSL_EXPORT size_t SSL_get_all_standard_cipher_names(const char **out,
+                                                        size_t max_out);
+
+
+// Cipher suite configuration.
+//
+// OpenSSL uses a mini-language to configure cipher suites. The language
+// maintains an ordered list of enabled ciphers, along with an ordered list of
+// disabled but available ciphers. Initially, all ciphers are disabled with a
+// default ordering. The cipher string is then interpreted as a sequence of
+// directives, separated by colons, each of which modifies this state.
+//
+// Most directives consist of a one character or empty opcode followed by a
+// selector which matches a subset of available ciphers.
+//
+// Available opcodes are:
+//
+// - The empty opcode enables and appends all matching disabled ciphers to the
+//   end of the enabled list. The newly appended ciphers are ordered relative to
+//   each other matching their order in the disabled list.
+//
+// - |-| disables all matching enabled ciphers and prepends them to the disabled
+//   list, with relative order from the enabled list preserved. This means the
+//   most recently disabled ciphers get highest preference relative to other
+//   disabled ciphers if re-enabled.
+//
+// - |+| moves all matching enabled ciphers to the end of the enabled list, with
+//   relative order preserved.
+//
+// - |!| deletes all matching ciphers, enabled or not, from either list. Deleted
+//   ciphers will not matched by future operations.
+//
+// A selector may be a specific cipher (using either the standard or OpenSSL
+// name for the cipher) or one or more rules separated by |+|. The final
+// selector matches the intersection of each rule. For instance, |AESGCM+aECDSA|
+// matches ECDSA-authenticated AES-GCM ciphers.
+//
+// Available cipher rules are:
+//
+// - |ALL| matches all ciphers, except for deprecated ciphers which must be
+//   named explicitly.
+//
+// - |kRSA|, |kDHE|, |kECDHE|, and |kPSK| match ciphers using plain RSA, DHE,
+//   ECDHE, and plain PSK key exchanges, respectively. Note that ECDHE_PSK is
+//   matched by |kECDHE| and not |kPSK|.
+//
+// - |aRSA|, |aECDSA|, and |aPSK| match ciphers authenticated by RSA, ECDSA, and
+//   a pre-shared key, respectively.
+//
+// - |RSA|, |DHE|, |ECDHE|, |PSK|, |ECDSA|, and |PSK| are aliases for the
+//   corresponding |k*| or |a*| cipher rule. |RSA| is an alias for |kRSA|, not
+//   |aRSA|.
+//
+// - |3DES|, |AES128|, |AES256|, |AES|, |AESGCM|, |CHACHA20| match ciphers
+//   whose bulk cipher use the corresponding encryption scheme. Note that
+//   |AES|, |AES128|, and |AES256| match both CBC and GCM ciphers.
+//
+// - |SHA1|, and its alias |SHA|, match legacy cipher suites using HMAC-SHA1.
+//
+// Deprecated cipher rules:
+//
+// - |kEDH|, |EDH|, |kEECDH|, and |EECDH| are legacy aliases for |kDHE|, |DHE|,
+//   |kECDHE|, and |ECDHE|, respectively.
+//
+// - |HIGH| is an alias for |ALL|.
+//
+// - |FIPS| is an alias for |HIGH|.
+//
+// - |SSLv3| and |TLSv1| match ciphers available in TLS 1.1 or earlier.
+//   |TLSv1_2| matches ciphers new in TLS 1.2. This is confusing and should not
+//   be used.
+//
+// Unknown rules are silently ignored by legacy APIs, and rejected by APIs with
+// "strict" in the name, which should be preferred. Cipher lists can be long
+// and it's easy to commit typos. Strict functions will also reject the use of
+// spaces, semi-colons and commas as alternative separators.
+//
+// The special |@STRENGTH| directive will sort all enabled ciphers by strength.
+//
+// The |DEFAULT| directive, when appearing at the front of the string, expands
+// to the default ordering of available ciphers.
+//
+// If configuring a server, one may also configure equal-preference groups to
+// partially respect the client's preferences when
+// |SSL_OP_CIPHER_SERVER_PREFERENCE| is enabled. Ciphers in an equal-preference
+// group have equal priority and use the client order. This may be used to
+// enforce that AEADs are preferred but select AES-GCM vs. ChaCha20-Poly1305
+// based on client preferences. An equal-preference is specified with square
+// brackets, combining multiple selectors separated by |. For example:
+//
+//   [TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256|TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256]
+//
+// Once an equal-preference group is used, future directives must be
+// opcode-less. Inside an equal-preference group, spaces are not allowed.
+//
+// TLS 1.3 ciphers do not participate in this mechanism and instead have a
+// built-in preference order. Functions to set cipher lists do not affect TLS
+// 1.3, and functions to query the cipher list do not include TLS 1.3 ciphers.
+
+// SSL_DEFAULT_CIPHER_LIST is the default cipher suite configuration. It is
+// substituted when a cipher string starts with 'DEFAULT'.
+#define SSL_DEFAULT_CIPHER_LIST "ALL"
+
+// SSL_CTX_set_strict_cipher_list configures the cipher list for |ctx|,
+// evaluating |str| as a cipher string and returning error if |str| contains
+// anything meaningless. It returns one on success and zero on failure.
+OPENSSL_EXPORT int SSL_CTX_set_strict_cipher_list(SSL_CTX *ctx,
+                                                  const char *str);
+
+// SSL_CTX_set_cipher_list configures the cipher list for |ctx|, evaluating
+// |str| as a cipher string. It returns one on success and zero on failure.
+//
+// Prefer to use |SSL_CTX_set_strict_cipher_list|. This function tolerates
+// garbage inputs, unless an empty cipher list results.
+OPENSSL_EXPORT int SSL_CTX_set_cipher_list(SSL_CTX *ctx, const char *str);
+
+// SSL_set_strict_cipher_list configures the cipher list for |ssl|, evaluating
+// |str| as a cipher string and returning error if |str| contains anything
+// meaningless. It returns one on success and zero on failure.
+OPENSSL_EXPORT int SSL_set_strict_cipher_list(SSL *ssl, const char *str);
+
+// SSL_set_cipher_list configures the cipher list for |ssl|, evaluating |str| as
+// a cipher string. It returns one on success and zero on failure.
+//
+// Prefer to use |SSL_set_strict_cipher_list|. This function tolerates garbage
+// inputs, unless an empty cipher list results.
+OPENSSL_EXPORT int SSL_set_cipher_list(SSL *ssl, const char *str);
+
+// SSL_CTX_get_ciphers returns the cipher list for |ctx|, in order of
+// preference.
+OPENSSL_EXPORT STACK_OF(SSL_CIPHER) *SSL_CTX_get_ciphers(const SSL_CTX *ctx);
+
+// SSL_CTX_cipher_in_group returns one if the |i|th cipher (see
+// |SSL_CTX_get_ciphers|) is in the same equipreference group as the one
+// following it and zero otherwise.
+OPENSSL_EXPORT int SSL_CTX_cipher_in_group(const SSL_CTX *ctx, size_t i);
+
+// SSL_get_ciphers returns the cipher list for |ssl|, in order of preference.
+OPENSSL_EXPORT STACK_OF(SSL_CIPHER) *SSL_get_ciphers(const SSL *ssl);
+
+
+// Connection information.
+
+// SSL_is_init_finished returns one if |ssl| has completed its initial handshake
+// and has no pending handshake. It returns zero otherwise.
+OPENSSL_EXPORT int SSL_is_init_finished(const SSL *ssl);
+
+// SSL_in_init returns one if |ssl| has a pending handshake and zero
+// otherwise.
+OPENSSL_EXPORT int SSL_in_init(const SSL *ssl);
+
+// SSL_in_false_start returns one if |ssl| has a pending handshake that is in
+// False Start. |SSL_write| may be called at this point without waiting for the
+// peer, but |SSL_read| will complete the handshake before accepting application
+// data.
+//
+// See also |SSL_MODE_ENABLE_FALSE_START|.
+OPENSSL_EXPORT int SSL_in_false_start(const SSL *ssl);
+
+// SSL_get_peer_certificate returns the peer's leaf certificate or NULL if the
+// peer did not use certificates. The caller must call |X509_free| on the
+// result to release it.
+OPENSSL_EXPORT X509 *SSL_get_peer_certificate(const SSL *ssl);
+
+// SSL_get_peer_cert_chain returns the peer's certificate chain or NULL if
+// unavailable or the peer did not use certificates. This is the unverified list
+// of certificates as sent by the peer, not the final chain built during
+// verification. The caller does not take ownership of the result.
+//
+// WARNING: This function behaves differently between client and server. If
+// |ssl| is a server, the returned chain does not include the leaf certificate.
+// If a client, it does.
+OPENSSL_EXPORT STACK_OF(X509) *SSL_get_peer_cert_chain(const SSL *ssl);
+
+// SSL_get_peer_full_cert_chain returns the peer's certificate chain, or NULL if
+// unavailable or the peer did not use certificates. This is the unverified list
+// of certificates as sent by the peer, not the final chain built during
+// verification. The caller does not take ownership of the result.
+//
+// This is the same as |SSL_get_peer_cert_chain| except that this function
+// always returns the full chain, i.e. the first element of the return value
+// (if any) will be the leaf certificate. In constrast,
+// |SSL_get_peer_cert_chain| returns only the intermediate certificates if the
+// |ssl| is a server.
+OPENSSL_EXPORT STACK_OF(X509) *SSL_get_peer_full_cert_chain(const SSL *ssl);
+
+// SSL_get0_peer_certificates returns the peer's certificate chain, or NULL if
+// unavailable or the peer did not use certificates. This is the unverified list
+// of certificates as sent by the peer, not the final chain built during
+// verification. The caller does not take ownership of the result.
+//
+// This is the |CRYPTO_BUFFER| variant of |SSL_get_peer_full_cert_chain|.
+OPENSSL_EXPORT const STACK_OF(CRYPTO_BUFFER) *
+    SSL_get0_peer_certificates(const SSL *ssl);
+
+// SSL_get0_signed_cert_timestamp_list sets |*out| and |*out_len| to point to
+// |*out_len| bytes of SCT information from the server. This is only valid if
+// |ssl| is a client. The SCT information is a SignedCertificateTimestampList
+// (including the two leading length bytes).
+// See https://tools.ietf.org/html/rfc6962#section-3.3
+// If no SCT was received then |*out_len| will be zero on return.
+//
+// WARNING: the returned data is not guaranteed to be well formed.
+OPENSSL_EXPORT void SSL_get0_signed_cert_timestamp_list(const SSL *ssl,
+                                                        const uint8_t **out,
+                                                        size_t *out_len);
+
+// SSL_get0_ocsp_response sets |*out| and |*out_len| to point to |*out_len|
+// bytes of an OCSP response from the server. This is the DER encoding of an
+// OCSPResponse type as defined in RFC 2560.
+//
+// WARNING: the returned data is not guaranteed to be well formed.
+OPENSSL_EXPORT void SSL_get0_ocsp_response(const SSL *ssl, const uint8_t **out,
+                                           size_t *out_len);
+
+// SSL_get_tls_unique writes at most |max_out| bytes of the tls-unique value
+// for |ssl| to |out| and sets |*out_len| to the number of bytes written. It
+// returns one on success or zero on error. In general |max_out| should be at
+// least 12.
+//
+// This function will always fail if the initial handshake has not completed.
+// The tls-unique value will change after a renegotiation but, since
+// renegotiations can be initiated by the server at any point, the higher-level
+// protocol must either leave them disabled or define states in which the
+// tls-unique value can be read.
+//
+// The tls-unique value is defined by
+// https://tools.ietf.org/html/rfc5929#section-3.1. Due to a weakness in the
+// TLS protocol, tls-unique is broken for resumed connections unless the
+// Extended Master Secret extension is negotiated. Thus this function will
+// return zero if |ssl| performed session resumption unless EMS was used when
+// negotiating the original session.
+OPENSSL_EXPORT int SSL_get_tls_unique(const SSL *ssl, uint8_t *out,
+                                      size_t *out_len, size_t max_out);
+
+// SSL_get_extms_support returns one if the Extended Master Secret extension or
+// TLS 1.3 was negotiated. Otherwise, it returns zero.
+OPENSSL_EXPORT int SSL_get_extms_support(const SSL *ssl);
+
+// SSL_get_current_cipher returns cipher suite used by |ssl|, or NULL if it has
+// not been negotiated yet.
+OPENSSL_EXPORT const SSL_CIPHER *SSL_get_current_cipher(const SSL *ssl);
+
+// SSL_session_reused returns one if |ssl| performed an abbreviated handshake
+// and zero otherwise.
+//
+// TODO(davidben): Hammer down the semantics of this API while a handshake,
+// initial or renego, is in progress.
+OPENSSL_EXPORT int SSL_session_reused(const SSL *ssl);
+
+// SSL_get_secure_renegotiation_support returns one if the peer supports secure
+// renegotiation (RFC 5746) or TLS 1.3. Otherwise, it returns zero.
+OPENSSL_EXPORT int SSL_get_secure_renegotiation_support(const SSL *ssl);
+
+// SSL_export_keying_material exports a value derived from the master secret, as
+// specified in RFC 5705. It writes |out_len| bytes to |out| given a label and
+// optional context. (Since a zero length context is allowed, the |use_context|
+// flag controls whether a context is included.)
+//
+// It returns one on success and zero otherwise.
+OPENSSL_EXPORT int SSL_export_keying_material(
+    SSL *ssl, uint8_t *out, size_t out_len, const char *label, size_t label_len,
+    const uint8_t *context, size_t context_len, int use_context);
+
+
+// Sessions.
+//
+// An |SSL_SESSION| represents an SSL session that may be resumed in an
+// abbreviated handshake. It is reference-counted and immutable. Once
+// established, an |SSL_SESSION| may be shared by multiple |SSL| objects on
+// different threads and must not be modified.
+//
+// Note the TLS notion of "session" is not suitable for application-level
+// session state. It is an optional caching mechanism for the handshake. Not all
+// connections within an application-level session will reuse TLS sessions. TLS
+// sessions may be dropped by the client or ignored by the server at any time.
+
+DECLARE_PEM_rw(SSL_SESSION, SSL_SESSION)
+
+// SSL_SESSION_new returns a newly-allocated blank |SSL_SESSION| or NULL on
+// error. This may be useful when writing tests but should otherwise not be
+// used.
+OPENSSL_EXPORT SSL_SESSION *SSL_SESSION_new(const SSL_CTX *ctx);
+
+// SSL_SESSION_up_ref increments the reference count of |session| and returns
+// one.
+OPENSSL_EXPORT int SSL_SESSION_up_ref(SSL_SESSION *session);
+
+// SSL_SESSION_free decrements the reference count of |session|. If it reaches
+// zero, all data referenced by |session| and |session| itself are released.
+OPENSSL_EXPORT void SSL_SESSION_free(SSL_SESSION *session);
+
+// SSL_SESSION_to_bytes serializes |in| into a newly allocated buffer and sets
+// |*out_data| to that buffer and |*out_len| to its length. The caller takes
+// ownership of the buffer and must call |OPENSSL_free| when done. It returns
+// one on success and zero on error.
+OPENSSL_EXPORT int SSL_SESSION_to_bytes(const SSL_SESSION *in,
+                                        uint8_t **out_data, size_t *out_len);
+
+// SSL_SESSION_to_bytes_for_ticket serializes |in|, but excludes the session
+// identification information, namely the session ID and ticket.
+OPENSSL_EXPORT int SSL_SESSION_to_bytes_for_ticket(const SSL_SESSION *in,
+                                                   uint8_t **out_data,
+                                                   size_t *out_len);
+
+// SSL_SESSION_from_bytes parses |in_len| bytes from |in| as an SSL_SESSION. It
+// returns a newly-allocated |SSL_SESSION| on success or NULL on error.
+OPENSSL_EXPORT SSL_SESSION *SSL_SESSION_from_bytes(
+    const uint8_t *in, size_t in_len, const SSL_CTX *ctx);
+
+// SSL_SESSION_get_version returns a string describing the TLS or DTLS version
+// |session| was established at. For example, "TLSv1.2" or "DTLSv1".
+OPENSSL_EXPORT const char *SSL_SESSION_get_version(const SSL_SESSION *session);
+
+// SSL_SESSION_get_protocol_version returns the TLS or DTLS version |session|
+// was established at.
+OPENSSL_EXPORT uint16_t
+SSL_SESSION_get_protocol_version(const SSL_SESSION *session);
+
+// SSL_SESSION_set_protocol_version sets |session|'s TLS or DTLS version to
+// |version|. This may be useful when writing tests but should otherwise not be
+// used. It returns one on success and zero on error.
+OPENSSL_EXPORT int SSL_SESSION_set_protocol_version(SSL_SESSION *session,
+                                                    uint16_t version);
+
+// SSL_MAX_SSL_SESSION_ID_LENGTH is the maximum length of an SSL session ID.
+#define SSL_MAX_SSL_SESSION_ID_LENGTH 32
+
+// SSL_SESSION_get_id returns a pointer to a buffer containing |session|'s
+// session ID and sets |*out_len| to its length.
+//
+// This function should only be used for implementing a TLS session cache. TLS
+// sessions are not suitable for application-level session state, and a session
+// ID is an implementation detail of the TLS resumption handshake mechanism. Not
+// all resumption flows use session IDs, and not all connections within an
+// application-level session will reuse TLS sessions.
+//
+// To determine if resumption occurred, use |SSL_session_reused| instead.
+// Comparing session IDs will not give the right result in all cases.
+//
+// As a workaround for some broken applications, BoringSSL sometimes synthesizes
+// arbitrary session IDs for non-ID-based sessions. This behavior may be
+// removed in the future.
+OPENSSL_EXPORT const uint8_t *SSL_SESSION_get_id(const SSL_SESSION *session,
+                                                 unsigned *out_len);
+
+// SSL_SESSION_set1_id sets |session|'s session ID to |sid|, It returns one on
+// success and zero on error. This function may be useful in writing tests but
+// otherwise should not be used.
+OPENSSL_EXPORT int SSL_SESSION_set1_id(SSL_SESSION *session, const uint8_t *sid,
+                                       size_t sid_len);
+
+// SSL_SESSION_get_time returns the time at which |session| was established in
+// seconds since the UNIX epoch.
+OPENSSL_EXPORT uint64_t SSL_SESSION_get_time(const SSL_SESSION *session);
+
+// SSL_SESSION_get_timeout returns the lifetime of |session| in seconds.
+OPENSSL_EXPORT uint32_t SSL_SESSION_get_timeout(const SSL_SESSION *session);
+
+// SSL_SESSION_get0_peer returns the peer leaf certificate stored in
+// |session|.
+//
+// TODO(davidben): This should return a const X509 *.
+OPENSSL_EXPORT X509 *SSL_SESSION_get0_peer(const SSL_SESSION *session);
+
+// SSL_SESSION_get0_peer_certificates returns the peer certificate chain stored
+// in |session|, or NULL if the peer did not use certificates. This is the
+// unverified list of certificates as sent by the peer, not the final chain
+// built during verification. The caller does not take ownership of the result.
+OPENSSL_EXPORT const STACK_OF(CRYPTO_BUFFER) *
+    SSL_SESSION_get0_peer_certificates(const SSL_SESSION *session);
+
+// SSL_SESSION_get0_signed_cert_timestamp_list sets |*out| and |*out_len| to
+// point to |*out_len| bytes of SCT information stored in |session|. This is
+// only valid for client sessions. The SCT information is a
+// SignedCertificateTimestampList (including the two leading length bytes). See
+// https://tools.ietf.org/html/rfc6962#section-3.3 If no SCT was received then
+// |*out_len| will be zero on return.
+//
+// WARNING: the returned data is not guaranteed to be well formed.
+OPENSSL_EXPORT void SSL_SESSION_get0_signed_cert_timestamp_list(
+    const SSL_SESSION *session, const uint8_t **out, size_t *out_len);
+
+// SSL_SESSION_get0_ocsp_response sets |*out| and |*out_len| to point to
+// |*out_len| bytes of an OCSP response from the server. This is the DER
+// encoding of an OCSPResponse type as defined in RFC 2560.
+//
+// WARNING: the returned data is not guaranteed to be well formed.
+OPENSSL_EXPORT void SSL_SESSION_get0_ocsp_response(const SSL_SESSION *session,
+                                                   const uint8_t **out,
+                                                   size_t *out_len);
+
+// SSL_MAX_MASTER_KEY_LENGTH is the maximum length of a master secret.
+#define SSL_MAX_MASTER_KEY_LENGTH 48
+
+// SSL_SESSION_get_master_key writes up to |max_out| bytes of |session|'s secret
+// to |out| and returns the number of bytes written. If |max_out| is zero, it
+// returns the size of the secret.
+OPENSSL_EXPORT size_t SSL_SESSION_get_master_key(const SSL_SESSION *session,
+                                                 uint8_t *out, size_t max_out);
+
+// SSL_SESSION_set_time sets |session|'s creation time to |time| and returns
+// |time|. This function may be useful in writing tests but otherwise should not
+// be used.
+OPENSSL_EXPORT uint64_t SSL_SESSION_set_time(SSL_SESSION *session,
+                                             uint64_t time);
+
+// SSL_SESSION_set_timeout sets |session|'s timeout to |timeout| and returns
+// one. This function may be useful in writing tests but otherwise should not
+// be used.
+OPENSSL_EXPORT uint32_t SSL_SESSION_set_timeout(SSL_SESSION *session,
+                                                uint32_t timeout);
+
+// SSL_SESSION_get0_id_context returns a pointer to a buffer containing
+// |session|'s session ID context (see |SSL_CTX_set_session_id_context|) and
+// sets |*out_len| to its length.
+OPENSSL_EXPORT const uint8_t *SSL_SESSION_get0_id_context(
+    const SSL_SESSION *session, unsigned *out_len);
+
+// SSL_SESSION_set1_id_context sets |session|'s session ID context (see
+// |SSL_CTX_set_session_id_context|) to |sid_ctx|. It returns one on success and
+// zero on error. This function may be useful in writing tests but otherwise
+// should not be used.
+OPENSSL_EXPORT int SSL_SESSION_set1_id_context(SSL_SESSION *session,
+                                               const uint8_t *sid_ctx,
+                                               size_t sid_ctx_len);
+
+// SSL_SESSION_should_be_single_use returns one if |session| should be
+// single-use (TLS 1.3 and later) and zero otherwise.
+//
+// If this function returns one, clients retain multiple sessions and use each
+// only once. This prevents passive observers from correlating connections with
+// tickets. See RFC 8446, appendix C.4. If it returns zero, |session| cannot be
+// used without leaking a correlator.
+OPENSSL_EXPORT int SSL_SESSION_should_be_single_use(const SSL_SESSION *session);
+
+// SSL_SESSION_is_resumable returns one if |session| is complete and contains a
+// session ID or ticket. It returns zero otherwise. Note this function does not
+// ensure |session| will be resumed. It may be expired, dropped by the server,
+// or associated with incompatible parameters.
+OPENSSL_EXPORT int SSL_SESSION_is_resumable(const SSL_SESSION *session);
+
+// SSL_SESSION_has_ticket returns one if |session| has a ticket and zero
+// otherwise.
+OPENSSL_EXPORT int SSL_SESSION_has_ticket(const SSL_SESSION *session);
+
+// SSL_SESSION_get0_ticket sets |*out_ticket| and |*out_len| to |session|'s
+// ticket, or NULL and zero if it does not have one. |out_ticket| may be NULL
+// if only the ticket length is needed.
+OPENSSL_EXPORT void SSL_SESSION_get0_ticket(const SSL_SESSION *session,
+                                            const uint8_t **out_ticket,
+                                            size_t *out_len);
+
+// SSL_SESSION_set_ticket sets |session|'s ticket to |ticket|. It returns one on
+// success and zero on error. This function may be useful in writing tests but
+// otherwise should not be used.
+OPENSSL_EXPORT int SSL_SESSION_set_ticket(SSL_SESSION *session,
+                                          const uint8_t *ticket,
+                                          size_t ticket_len);
+
+// SSL_SESSION_get_ticket_lifetime_hint returns ticket lifetime hint of
+// |session| in seconds or zero if none was set.
+OPENSSL_EXPORT uint32_t
+SSL_SESSION_get_ticket_lifetime_hint(const SSL_SESSION *session);
+
+// SSL_SESSION_get0_cipher returns the cipher negotiated by the connection which
+// established |session|.
+//
+// Note that, in TLS 1.3, there is no guarantee that resumptions with |session|
+// will use that cipher. Prefer calling |SSL_get_current_cipher| on the |SSL|
+// instead.
+OPENSSL_EXPORT const SSL_CIPHER *SSL_SESSION_get0_cipher(
+    const SSL_SESSION *session);
+
+// SSL_SESSION_has_peer_sha256 returns one if |session| has a SHA-256 hash of
+// the peer's certificate retained and zero if the peer did not present a
+// certificate or if this was not enabled when |session| was created. See also
+// |SSL_CTX_set_retain_only_sha256_of_client_certs|.
+OPENSSL_EXPORT int SSL_SESSION_has_peer_sha256(const SSL_SESSION *session);
+
+// SSL_SESSION_get0_peer_sha256 sets |*out_ptr| and |*out_len| to the SHA-256
+// hash of the peer certificate retained in |session|, or NULL and zero if it
+// does not have one. See also |SSL_CTX_set_retain_only_sha256_of_client_certs|.
+OPENSSL_EXPORT void SSL_SESSION_get0_peer_sha256(const SSL_SESSION *session,
+                                                 const uint8_t **out_ptr,
+                                                 size_t *out_len);
+
+
+// Session caching.
+//
+// Session caching allows connections to be established more efficiently based
+// on saved parameters from a previous connection, called a session (see
+// |SSL_SESSION|). The client offers a saved session, using an opaque identifier
+// from a previous connection. The server may accept the session, if it has the
+// parameters available. Otherwise, it will decline and continue with a full
+// handshake.
+//
+// This requires both the client and the server to retain session state. A
+// client does so with a stateful session cache. A server may do the same or, if
+// supported by both sides, statelessly using session tickets. For more
+// information on the latter, see the next section.
+//
+// For a server, the library implements a built-in internal session cache as an
+// in-memory hash table. Servers may also use |SSL_CTX_sess_set_get_cb| and
+// |SSL_CTX_sess_set_new_cb| to implement a custom external session cache. In
+// particular, this may be used to share a session cache between multiple
+// servers in a large deployment. An external cache may be used in addition to
+// or instead of the internal one. Use |SSL_CTX_set_session_cache_mode| to
+// toggle the internal cache.
+//
+// For a client, the only option is an external session cache. Clients may use
+// |SSL_CTX_sess_set_new_cb| to register a callback for when new sessions are
+// available. These may be cached and, in subsequent compatible connections,
+// configured with |SSL_set_session|.
+//
+// Note that offering or accepting a session short-circuits certificate
+// verification and most parameter negotiation. Resuming sessions across
+// different contexts may result in security failures and surprising
+// behavior. For a typical client, this means sessions for different hosts must
+// be cached under different keys. A client that connects to the same host with,
+// e.g., different cipher suite settings or client certificates should also use
+// separate session caches between those contexts. Servers should also partition
+// session caches between SNI hosts with |SSL_CTX_set_session_id_context|.
+//
+// Note also, in TLS 1.2 and earlier, offering sessions allows passive observers
+// to correlate different client connections. TLS 1.3 and later fix this,
+// provided clients use sessions at most once. Session caches are managed by the
+// caller in BoringSSL, so this must be implemented externally. See
+// |SSL_SESSION_should_be_single_use| for details.
+
+// SSL_SESS_CACHE_OFF disables all session caching.
+#define SSL_SESS_CACHE_OFF 0x0000
+
+// SSL_SESS_CACHE_CLIENT enables session caching for a client. The internal
+// cache is never used on a client, so this only enables the callbacks.
+#define SSL_SESS_CACHE_CLIENT 0x0001
+
+// SSL_SESS_CACHE_SERVER enables session caching for a server.
+#define SSL_SESS_CACHE_SERVER 0x0002
+
+// SSL_SESS_CACHE_BOTH enables session caching for both client and server.
+#define SSL_SESS_CACHE_BOTH (SSL_SESS_CACHE_CLIENT | SSL_SESS_CACHE_SERVER)
+
+// SSL_SESS_CACHE_NO_AUTO_CLEAR disables automatically calling
+// |SSL_CTX_flush_sessions| every 255 connections.
+#define SSL_SESS_CACHE_NO_AUTO_CLEAR 0x0080
+
+// SSL_SESS_CACHE_NO_INTERNAL_LOOKUP, on a server, disables looking up a session
+// from the internal session cache.
+#define SSL_SESS_CACHE_NO_INTERNAL_LOOKUP 0x0100
+
+// SSL_SESS_CACHE_NO_INTERNAL_STORE, on a server, disables storing sessions in
+// the internal session cache.
+#define SSL_SESS_CACHE_NO_INTERNAL_STORE 0x0200
+
+// SSL_SESS_CACHE_NO_INTERNAL, on a server, disables the internal session
+// cache.
+#define SSL_SESS_CACHE_NO_INTERNAL \
+    (SSL_SESS_CACHE_NO_INTERNAL_LOOKUP | SSL_SESS_CACHE_NO_INTERNAL_STORE)
+
+// SSL_CTX_set_session_cache_mode sets the session cache mode bits for |ctx| to
+// |mode|. It returns the previous value.
+OPENSSL_EXPORT int SSL_CTX_set_session_cache_mode(SSL_CTX *ctx, int mode);
+
+// SSL_CTX_get_session_cache_mode returns the session cache mode bits for
+// |ctx|
+OPENSSL_EXPORT int SSL_CTX_get_session_cache_mode(const SSL_CTX *ctx);
+
+// SSL_set_session, for a client, configures |ssl| to offer to resume |session|
+// in the initial handshake and returns one. The caller retains ownership of
+// |session|. Note that configuring a session assumes the authentication in the
+// session is valid. For callers that wish to revalidate the session before
+// offering, see |SSL_SESSION_get0_peer_certificates|,
+// |SSL_SESSION_get0_signed_cert_timestamp_list|, and
+// |SSL_SESSION_get0_ocsp_response|.
+//
+// It is an error to call this function after the handshake has begun.
+OPENSSL_EXPORT int SSL_set_session(SSL *ssl, SSL_SESSION *session);
+
+// SSL_DEFAULT_SESSION_TIMEOUT is the default lifetime, in seconds, of a
+// session in TLS 1.2 or earlier. This is how long we are willing to use the
+// secret to encrypt traffic without fresh key material.
+#define SSL_DEFAULT_SESSION_TIMEOUT (2 * 60 * 60)
+
+// SSL_DEFAULT_SESSION_PSK_DHE_TIMEOUT is the default lifetime, in seconds, of a
+// session for TLS 1.3 psk_dhe_ke. This is how long we are willing to use the
+// secret as an authenticator.
+#define SSL_DEFAULT_SESSION_PSK_DHE_TIMEOUT (2 * 24 * 60 * 60)
+
+// SSL_DEFAULT_SESSION_AUTH_TIMEOUT is the default non-renewable lifetime, in
+// seconds, of a TLS 1.3 session. This is how long we are willing to trust the
+// signature in the initial handshake.
+#define SSL_DEFAULT_SESSION_AUTH_TIMEOUT (7 * 24 * 60 * 60)
+
+// SSL_CTX_set_timeout sets the lifetime, in seconds, of TLS 1.2 (or earlier)
+// sessions created in |ctx| to |timeout|.
+OPENSSL_EXPORT uint32_t SSL_CTX_set_timeout(SSL_CTX *ctx, uint32_t timeout);
+
+// SSL_CTX_set_session_psk_dhe_timeout sets the lifetime, in seconds, of TLS 1.3
+// sessions created in |ctx| to |timeout|.
+OPENSSL_EXPORT void SSL_CTX_set_session_psk_dhe_timeout(SSL_CTX *ctx,
+                                                        uint32_t timeout);
+
+// SSL_CTX_get_timeout returns the lifetime, in seconds, of TLS 1.2 (or earlier)
+// sessions created in |ctx|.
+OPENSSL_EXPORT uint32_t SSL_CTX_get_timeout(const SSL_CTX *ctx);
+
+// SSL_MAX_SID_CTX_LENGTH is the maximum length of a session ID context.
+#define SSL_MAX_SID_CTX_LENGTH 32
+
+// SSL_CTX_set_session_id_context sets |ctx|'s session ID context to |sid_ctx|.
+// It returns one on success and zero on error. The session ID context is an
+// application-defined opaque byte string. A session will not be used in a
+// connection without a matching session ID context.
+//
+// For a server, if |SSL_VERIFY_PEER| is enabled, it is an error to not set a
+// session ID context.
+OPENSSL_EXPORT int SSL_CTX_set_session_id_context(SSL_CTX *ctx,
+                                                  const uint8_t *sid_ctx,
+                                                  size_t sid_ctx_len);
+
+// SSL_set_session_id_context sets |ssl|'s session ID context to |sid_ctx|. It
+// returns one on success and zero on error. See also
+// |SSL_CTX_set_session_id_context|.
+OPENSSL_EXPORT int SSL_set_session_id_context(SSL *ssl, const uint8_t *sid_ctx,
+                                              size_t sid_ctx_len);
+
+// SSL_get0_session_id_context returns a pointer to |ssl|'s session ID context
+// and sets |*out_len| to its length.  It returns NULL on error.
+OPENSSL_EXPORT const uint8_t *SSL_get0_session_id_context(const SSL *ssl,
+                                                          size_t *out_len);
+
+// SSL_SESSION_CACHE_MAX_SIZE_DEFAULT is the default maximum size of a session
+// cache.
+#define SSL_SESSION_CACHE_MAX_SIZE_DEFAULT (1024 * 20)
+
+// SSL_CTX_sess_set_cache_size sets the maximum size of |ctx|'s internal session
+// cache to |size|. It returns the previous value.
+OPENSSL_EXPORT unsigned long SSL_CTX_sess_set_cache_size(SSL_CTX *ctx,
+                                                         unsigned long size);
+
+// SSL_CTX_sess_get_cache_size returns the maximum size of |ctx|'s internal
+// session cache.
+OPENSSL_EXPORT unsigned long SSL_CTX_sess_get_cache_size(const SSL_CTX *ctx);
+
+// SSL_CTX_sess_number returns the number of sessions in |ctx|'s internal
+// session cache.
+OPENSSL_EXPORT size_t SSL_CTX_sess_number(const SSL_CTX *ctx);
+
+// SSL_CTX_add_session inserts |session| into |ctx|'s internal session cache. It
+// returns one on success and zero on error or if |session| is already in the
+// cache. The caller retains its reference to |session|.
+OPENSSL_EXPORT int SSL_CTX_add_session(SSL_CTX *ctx, SSL_SESSION *session);
+
+// SSL_CTX_remove_session removes |session| from |ctx|'s internal session cache.
+// It returns one on success and zero if |session| was not in the cache.
+OPENSSL_EXPORT int SSL_CTX_remove_session(SSL_CTX *ctx, SSL_SESSION *session);
+
+// SSL_CTX_flush_sessions removes all sessions from |ctx| which have expired as
+// of time |time|. If |time| is zero, all sessions are removed.
+OPENSSL_EXPORT void SSL_CTX_flush_sessions(SSL_CTX *ctx, uint64_t time);
+
+// SSL_CTX_sess_set_new_cb sets the callback to be called when a new session is
+// established and ready to be cached. If the session cache is disabled (the
+// appropriate one of |SSL_SESS_CACHE_CLIENT| or |SSL_SESS_CACHE_SERVER| is
+// unset), the callback is not called.
+//
+// The callback is passed a reference to |session|. It returns one if it takes
+// ownership (and then calls |SSL_SESSION_free| when done) and zero otherwise. A
+// consumer which places |session| into an in-memory cache will likely return
+// one, with the cache calling |SSL_SESSION_free|. A consumer which serializes
+// |session| with |SSL_SESSION_to_bytes| may not need to retain |session| and
+// will likely return zero. Returning one is equivalent to calling
+// |SSL_SESSION_up_ref| and then returning zero.
+//
+// Note: For a client, the callback may be called on abbreviated handshakes if a
+// ticket is renewed. Further, it may not be called until some time after
+// |SSL_do_handshake| or |SSL_connect| completes if False Start is enabled. Thus
+// it's recommended to use this callback over calling |SSL_get_session| on
+// handshake completion.
+OPENSSL_EXPORT void SSL_CTX_sess_set_new_cb(
+    SSL_CTX *ctx, int (*new_session_cb)(SSL *ssl, SSL_SESSION *session));
+
+// SSL_CTX_sess_get_new_cb returns the callback set by
+// |SSL_CTX_sess_set_new_cb|.
+OPENSSL_EXPORT int (*SSL_CTX_sess_get_new_cb(SSL_CTX *ctx))(
+    SSL *ssl, SSL_SESSION *session);
+
+// SSL_CTX_sess_set_remove_cb sets a callback which is called when a session is
+// removed from the internal session cache.
+//
+// TODO(davidben): What is the point of this callback? It seems useless since it
+// only fires on sessions in the internal cache.
+OPENSSL_EXPORT void SSL_CTX_sess_set_remove_cb(
+    SSL_CTX *ctx,
+    void (*remove_session_cb)(SSL_CTX *ctx, SSL_SESSION *session));
+
+// SSL_CTX_sess_get_remove_cb returns the callback set by
+// |SSL_CTX_sess_set_remove_cb|.
+OPENSSL_EXPORT void (*SSL_CTX_sess_get_remove_cb(SSL_CTX *ctx))(
+    SSL_CTX *ctx, SSL_SESSION *session);
+
+// SSL_CTX_sess_set_get_cb sets a callback to look up a session by ID for a
+// server. The callback is passed the session ID and should return a matching
+// |SSL_SESSION| or NULL if not found. It should set |*out_copy| to zero and
+// return a new reference to the session. This callback is not used for a
+// client.
+//
+// For historical reasons, if |*out_copy| is set to one (default), the SSL
+// library will take a new reference to the returned |SSL_SESSION|, expecting
+// the callback to return a non-owning pointer. This is not recommended. If
+// |ctx| and thus the callback is used on multiple threads, the session may be
+// removed and invalidated before the SSL library calls |SSL_SESSION_up_ref|,
+// whereas the callback may synchronize internally.
+//
+// To look up a session asynchronously, the callback may return
+// |SSL_magic_pending_session_ptr|. See the documentation for that function and
+// |SSL_ERROR_PENDING_SESSION|.
+//
+// If the internal session cache is enabled, the callback is only consulted if
+// the internal cache does not return a match.
+OPENSSL_EXPORT void SSL_CTX_sess_set_get_cb(
+    SSL_CTX *ctx, SSL_SESSION *(*get_session_cb)(SSL *ssl, const uint8_t *id,
+                                                 int id_len, int *out_copy));
+
+// SSL_CTX_sess_get_get_cb returns the callback set by
+// |SSL_CTX_sess_set_get_cb|.
+OPENSSL_EXPORT SSL_SESSION *(*SSL_CTX_sess_get_get_cb(SSL_CTX *ctx))(
+    SSL *ssl, const uint8_t *id, int id_len, int *out_copy);
+
+// SSL_magic_pending_session_ptr returns a magic |SSL_SESSION|* which indicates
+// that the session isn't currently unavailable. |SSL_get_error| will then
+// return |SSL_ERROR_PENDING_SESSION| and the handshake can be retried later
+// when the lookup has completed.
+OPENSSL_EXPORT SSL_SESSION *SSL_magic_pending_session_ptr(void);
+
+
+// Session tickets.
+//
+// Session tickets, from RFC 5077, allow session resumption without server-side
+// state. The server maintains a secret ticket key and sends the client opaque
+// encrypted session parameters, called a ticket. When offering the session, the
+// client sends the ticket which the server decrypts to recover session state.
+// Session tickets are enabled by default but may be disabled with
+// |SSL_OP_NO_TICKET|.
+//
+// On the client, ticket-based sessions use the same APIs as ID-based tickets.
+// Callers do not need to handle them differently.
+//
+// On the server, tickets are encrypted and authenticated with a secret key.
+// By default, an |SSL_CTX| will manage session ticket encryption keys by
+// generating them internally and rotating every 48 hours. Tickets are minted
+// and processed transparently. The following functions may be used to configure
+// a persistent key or implement more custom behavior, including key rotation
+// and sharing keys between multiple servers in a large deployment. There are
+// three levels of customisation possible:
+//
+// 1) One can simply set the keys with |SSL_CTX_set_tlsext_ticket_keys|.
+// 2) One can configure an |EVP_CIPHER_CTX| and |HMAC_CTX| directly for
+//    encryption and authentication.
+// 3) One can configure an |SSL_TICKET_AEAD_METHOD| to have more control
+//    and the option of asynchronous decryption.
+//
+// An attacker that compromises a server's session ticket key can impersonate
+// the server and, prior to TLS 1.3, retroactively decrypt all application
+// traffic from sessions using that ticket key. Thus ticket keys must be
+// regularly rotated for forward secrecy. Note the default key is rotated
+// automatically once every 48 hours but manually configured keys are not.
+
+// SSL_DEFAULT_TICKET_KEY_ROTATION_INTERVAL is the interval with which the
+// default session ticket encryption key is rotated, if in use. If any
+// non-default ticket encryption mechanism is configured, automatic rotation is
+// disabled.
+#define SSL_DEFAULT_TICKET_KEY_ROTATION_INTERVAL (2 * 24 * 60 * 60)
+
+// SSL_CTX_get_tlsext_ticket_keys writes |ctx|'s session ticket key material to
+// |len| bytes of |out|. It returns one on success and zero if |len| is not
+// 48. If |out| is NULL, it returns 48 instead.
+OPENSSL_EXPORT int SSL_CTX_get_tlsext_ticket_keys(SSL_CTX *ctx, void *out,
+                                                  size_t len);
+
+// SSL_CTX_set_tlsext_ticket_keys sets |ctx|'s session ticket key material to
+// |len| bytes of |in|. It returns one on success and zero if |len| is not
+// 48. If |in| is NULL, it returns 48 instead.
+OPENSSL_EXPORT int SSL_CTX_set_tlsext_ticket_keys(SSL_CTX *ctx, const void *in,
+                                                  size_t len);
+
+// SSL_TICKET_KEY_NAME_LEN is the length of the key name prefix of a session
+// ticket.
+#define SSL_TICKET_KEY_NAME_LEN 16
+
+// SSL_CTX_set_tlsext_ticket_key_cb sets the ticket callback to |callback| and
+// returns one. |callback| will be called when encrypting a new ticket and when
+// decrypting a ticket from the client.
+//
+// In both modes, |ctx| and |hmac_ctx| will already have been initialized with
+// |EVP_CIPHER_CTX_init| and |HMAC_CTX_init|, respectively. |callback|
+// configures |hmac_ctx| with an HMAC digest and key, and configures |ctx|
+// for encryption or decryption, based on the mode.
+//
+// When encrypting a new ticket, |encrypt| will be one. It writes a public
+// 16-byte key name to |key_name| and a fresh IV to |iv|. The output IV length
+// must match |EVP_CIPHER_CTX_iv_length| of the cipher selected. In this mode,
+// |callback| returns 1 on success and -1 on error.
+//
+// When decrypting a ticket, |encrypt| will be zero. |key_name| will point to a
+// 16-byte key name and |iv| points to an IV. The length of the IV consumed must
+// match |EVP_CIPHER_CTX_iv_length| of the cipher selected. In this mode,
+// |callback| returns -1 to abort the handshake, 0 if decrypting the ticket
+// failed, and 1 or 2 on success. If it returns 2, the ticket will be renewed.
+// This may be used to re-key the ticket.
+//
+// WARNING: |callback| wildly breaks the usual return value convention and is
+// called in two different modes.
+OPENSSL_EXPORT int SSL_CTX_set_tlsext_ticket_key_cb(
+    SSL_CTX *ctx, int (*callback)(SSL *ssl, uint8_t *key_name, uint8_t *iv,
+                                  EVP_CIPHER_CTX *ctx, HMAC_CTX *hmac_ctx,
+                                  int encrypt));
+
+// ssl_ticket_aead_result_t enumerates the possible results from decrypting a
+// ticket with an |SSL_TICKET_AEAD_METHOD|.
+enum ssl_ticket_aead_result_t BORINGSSL_ENUM_INT {
+  // ssl_ticket_aead_success indicates that the ticket was successfully
+  // decrypted.
+  ssl_ticket_aead_success,
+  // ssl_ticket_aead_retry indicates that the operation could not be
+  // immediately completed and must be reattempted, via |open|, at a later
+  // point.
+  ssl_ticket_aead_retry,
+  // ssl_ticket_aead_ignore_ticket indicates that the ticket should be ignored
+  // (i.e. is corrupt or otherwise undecryptable).
+  ssl_ticket_aead_ignore_ticket,
+  // ssl_ticket_aead_error indicates that a fatal error occured and the
+  // handshake should be terminated.
+  ssl_ticket_aead_error,
+};
+
+// ssl_ticket_aead_method_st (aka |SSL_TICKET_AEAD_METHOD|) contains methods
+// for encrypting and decrypting session tickets.
+struct ssl_ticket_aead_method_st {
+  // max_overhead returns the maximum number of bytes of overhead that |seal|
+  // may add.
+  size_t (*max_overhead)(SSL *ssl);
+
+  // seal encrypts and authenticates |in_len| bytes from |in|, writes, at most,
+  // |max_out_len| bytes to |out|, and puts the number of bytes written in
+  // |*out_len|. The |in| and |out| buffers may be equal but will not otherwise
+  // alias. It returns one on success or zero on error.
+  int (*seal)(SSL *ssl, uint8_t *out, size_t *out_len, size_t max_out_len,
+              const uint8_t *in, size_t in_len);
+
+  // open authenticates and decrypts |in_len| bytes from |in|, writes, at most,
+  // |max_out_len| bytes of plaintext to |out|, and puts the number of bytes
+  // written in |*out_len|. The |in| and |out| buffers may be equal but will
+  // not otherwise alias. See |ssl_ticket_aead_result_t| for details of the
+  // return values. In the case that a retry is indicated, the caller should
+  // arrange for the high-level operation on |ssl| to be retried when the
+  // operation is completed, which will result in another call to |open|.
+  enum ssl_ticket_aead_result_t (*open)(SSL *ssl, uint8_t *out, size_t *out_len,
+                                        size_t max_out_len, const uint8_t *in,
+                                        size_t in_len);
+};
+
+// SSL_CTX_set_ticket_aead_method configures a custom ticket AEAD method table
+// on |ctx|. |aead_method| must remain valid for the lifetime of |ctx|.
+OPENSSL_EXPORT void SSL_CTX_set_ticket_aead_method(
+    SSL_CTX *ctx, const SSL_TICKET_AEAD_METHOD *aead_method);
+
+// SSL_process_tls13_new_session_ticket processes an unencrypted TLS 1.3
+// NewSessionTicket message from |buf| and returns a resumable |SSL_SESSION|,
+// or NULL on error. The caller takes ownership of the returned session and
+// must call |SSL_SESSION_free| to free it.
+//
+// |buf| contains |buf_len| bytes that represents a complete NewSessionTicket
+// message including its header, i.e., one byte for the type (0x04) and three
+// bytes for the length. |buf| must contain only one such message.
+//
+// This function may be used to process NewSessionTicket messages in TLS 1.3
+// clients that are handling the record layer externally.
+OPENSSL_EXPORT SSL_SESSION *SSL_process_tls13_new_session_ticket(
+    SSL *ssl, const uint8_t *buf, size_t buf_len);
+
+// SSL_CTX_set_num_tickets configures |ctx| to send |num_tickets| immediately
+// after a successful TLS 1.3 handshake as a server. It returns one. Large
+// values of |num_tickets| will be capped within the library.
+//
+// By default, BoringSSL sends two tickets.
+OPENSSL_EXPORT int SSL_CTX_set_num_tickets(SSL_CTX *ctx, size_t num_tickets);
+
+// SSL_CTX_get_num_tickets returns the number of tickets |ctx| will send
+// immediately after a successful TLS 1.3 handshake as a server.
+OPENSSL_EXPORT size_t SSL_CTX_get_num_tickets(const SSL_CTX *ctx);
+
+
+// Diffie-Hellman groups and ephemeral key exchanges.
+//
+// Most TLS handshakes (ECDHE cipher suites in TLS 1.2, and all supported TLS
+// 1.3 modes) incorporate an ephemeral key exchange, most commonly using
+// Elliptic Curve Diffie-Hellman (ECDH), as described in RFC 8422. The key
+// exchange algorithm is negotiated separately from the cipher suite, using
+// NamedGroup values, which define Diffie-Hellman groups.
+//
+// Historically, these values were known as "curves", in reference to ECDH, and
+// some APIs refer to the original name. RFC 7919 renamed them to "groups" in
+// reference to Diffie-Hellman in general. These values are also used to select
+// experimental post-quantum KEMs. Though not Diffie-Hellman groups, KEMs can
+// fill a similar role in TLS, so they use the same codepoints.
+//
+// In TLS 1.2, the ECDH values also negotiate elliptic curves used in ECDSA. In
+// TLS 1.3 and later, ECDSA curves are part of the signature algorithm. See
+// |SSL_SIGN_*|.
+
+// SSL_GROUP_* define TLS group IDs.
+#define SSL_GROUP_SECP224R1 21
+#define SSL_GROUP_SECP256R1 23
+#define SSL_GROUP_SECP384R1 24
+#define SSL_GROUP_SECP521R1 25
+#define SSL_GROUP_X25519 29
+#define SSL_GROUP_X25519_KYBER768_DRAFT00 0x6399
+
+// SSL_CTX_set1_group_ids sets the preferred groups for |ctx| to |group_ids|.
+// Each element of |group_ids| should be one of the |SSL_GROUP_*| constants. It
+// returns one on success and zero on failure.
+OPENSSL_EXPORT int SSL_CTX_set1_group_ids(SSL_CTX *ctx,
+                                          const uint16_t *group_ids,
+                                          size_t num_group_ids);
+
+// SSL_set1_group_ids sets the preferred groups for |ssl| to |group_ids|. Each
+// element of |group_ids| should be one of the |SSL_GROUP_*| constants. It
+// returns one on success and zero on failure.
+OPENSSL_EXPORT int SSL_set1_group_ids(SSL *ssl, const uint16_t *group_ids,
+                                      size_t num_group_ids);
+
+// SSL_get_group_id returns the ID of the group used by |ssl|'s most recently
+// completed handshake, or 0 if not applicable.
+OPENSSL_EXPORT uint16_t SSL_get_group_id(const SSL *ssl);
+
+// SSL_get_group_name returns a human-readable name for the group specified by
+// the given TLS group ID, or NULL if the group is unknown.
+OPENSSL_EXPORT const char *SSL_get_group_name(uint16_t group_id);
+
+// SSL_get_all_group_names outputs a list of possible strings
+// |SSL_get_group_name| may return in this version of BoringSSL. It writes at
+// most |max_out| entries to |out| and returns the total number it would have
+// written, if |max_out| had been large enough. |max_out| may be initially set
+// to zero to size the output.
+//
+// This function is only intended to help initialize tables in callers that want
+// possible strings pre-declared. This list would not be suitable to set a list
+// of supported features. It is in no particular order, and may contain
+// placeholder, experimental, or deprecated values that do not apply to every
+// caller. Future versions of BoringSSL may also return strings not in this
+// list, so this does not apply if, say, sending strings across services.
+OPENSSL_EXPORT size_t SSL_get_all_group_names(const char **out, size_t max_out);
+
+// The following APIs also configure Diffie-Hellman groups, but use |NID_*|
+// constants instead of |SSL_GROUP_*| constants. These are provided for OpenSSL
+// compatibility. Where NIDs are unstable constants specific to OpenSSL and
+// BoringSSL, group IDs are defined by the TLS protocol. Prefer the group ID
+// representation if storing persistently, or exporting to another process or
+// library.
+
+// SSL_CTX_set1_groups sets the preferred groups for |ctx| to be |groups|. Each
+// element of |groups| should be a |NID_*| constant from nid.h. It returns one
+// on success and zero on failure.
+OPENSSL_EXPORT int SSL_CTX_set1_groups(SSL_CTX *ctx, const int *groups,
+                                       size_t num_groups);
+
+// SSL_set1_groups sets the preferred groups for |ssl| to be |groups|. Each
+// element of |groups| should be a |NID_*| constant from nid.h. It returns one
+// on success and zero on failure.
+OPENSSL_EXPORT int SSL_set1_groups(SSL *ssl, const int *groups,
+                                   size_t num_groups);
+
+// SSL_CTX_set1_groups_list decodes |groups| as a colon-separated list of group
+// names (e.g. "X25519" or "P-256") and sets |ctx|'s preferred groups to the
+// result. It returns one on success and zero on failure.
+OPENSSL_EXPORT int SSL_CTX_set1_groups_list(SSL_CTX *ctx, const char *groups);
+
+// SSL_set1_groups_list decodes |groups| as a colon-separated list of group
+// names (e.g. "X25519" or "P-256") and sets |ssl|'s preferred groups to the
+// result. It returns one on success and zero on failure.
+OPENSSL_EXPORT int SSL_set1_groups_list(SSL *ssl, const char *groups);
+
+// SSL_get_negotiated_group returns the NID of the group used by |ssl|'s most
+// recently completed handshake, or |NID_undef| if not applicable.
+OPENSSL_EXPORT int SSL_get_negotiated_group(const SSL *ssl);
+
+
+// Certificate verification.
+//
+// SSL may authenticate either endpoint with an X.509 certificate. Typically
+// this is used to authenticate the server to the client. These functions
+// configure certificate verification.
+//
+// WARNING: By default, certificate verification errors on a client are not
+// fatal. See |SSL_VERIFY_NONE| This may be configured with
+// |SSL_CTX_set_verify|.
+//
+// By default clients are anonymous but a server may request a certificate from
+// the client by setting |SSL_VERIFY_PEER|.
+//
+// Many of these functions use OpenSSL's legacy X.509 stack which is
+// underdocumented and deprecated, but the replacement isn't ready yet. For
+// now, consumers may use the existing stack or bypass it by performing
+// certificate verification externally. This may be done with
+// |SSL_CTX_set_cert_verify_callback| or by extracting the chain with
+// |SSL_get_peer_cert_chain| after the handshake. In the future, functions will
+// be added to use the SSL stack without dependency on any part of the legacy
+// X.509 and ASN.1 stack.
+//
+// To augment certificate verification, a client may also enable OCSP stapling
+// (RFC 6066) and Certificate Transparency (RFC 6962) extensions.
+
+// SSL_VERIFY_NONE, on a client, verifies the server certificate but does not
+// make errors fatal. The result may be checked with |SSL_get_verify_result|. On
+// a server it does not request a client certificate. This is the default.
+#define SSL_VERIFY_NONE 0x00
+
+// SSL_VERIFY_PEER, on a client, makes server certificate errors fatal. On a
+// server it requests a client certificate and makes errors fatal. However,
+// anonymous clients are still allowed. See
+// |SSL_VERIFY_FAIL_IF_NO_PEER_CERT|.
+#define SSL_VERIFY_PEER 0x01
+
+// SSL_VERIFY_FAIL_IF_NO_PEER_CERT configures a server to reject connections if
+// the client declines to send a certificate. This flag must be used together
+// with |SSL_VERIFY_PEER|, otherwise it won't work.
+#define SSL_VERIFY_FAIL_IF_NO_PEER_CERT 0x02
+
+// SSL_VERIFY_PEER_IF_NO_OBC configures a server to request a client certificate
+// if and only if Channel ID is not negotiated.
+#define SSL_VERIFY_PEER_IF_NO_OBC 0x04
+
+// SSL_CTX_set_verify configures certificate verification behavior. |mode| is
+// one of the |SSL_VERIFY_*| values defined above. |callback| should be NULL.
+//
+// If |callback| is non-NULL, it is called as in |X509_STORE_CTX_set_verify_cb|,
+// which is a deprecated and fragile mechanism to run the default certificate
+// verification process, but suppress individual errors in it. See
+// |X509_STORE_CTX_set_verify_cb| for details, If set, the callback may use
+// |SSL_get_ex_data_X509_STORE_CTX_idx| with |X509_STORE_CTX_get_ex_data| to
+// look up the |SSL| from |store_ctx|.
+//
+// WARNING: |callback| is not suitable for implementing custom certificate
+// check, accepting all certificates, or extracting the certificate after
+// verification. It does not replace the default process and is called multiple
+// times throughout that process. It is also very difficult to implement this
+// callback safely, without inadvertently relying on implementation details or
+// making incorrect assumptions about when the callback is called.
+//
+// Instead, use |SSL_CTX_set_custom_verify| or
+// |SSL_CTX_set_cert_verify_callback| to customize certificate verification.
+// Those callbacks can inspect the peer-sent chain, call |X509_verify_cert| and
+// inspect the result, or perform other operations more straightforwardly.
+OPENSSL_EXPORT void SSL_CTX_set_verify(
+    SSL_CTX *ctx, int mode, int (*callback)(int ok, X509_STORE_CTX *store_ctx));
+
+// SSL_set_verify configures certificate verification behavior. |mode| is one of
+// the |SSL_VERIFY_*| values defined above. |callback| should be NULL.
+//
+// If |callback| is non-NULL, it is called as in |X509_STORE_CTX_set_verify_cb|,
+// which is a deprecated and fragile mechanism to run the default certificate
+// verification process, but suppress individual errors in it. See
+// |X509_STORE_CTX_set_verify_cb| for details, If set, the callback may use
+// |SSL_get_ex_data_X509_STORE_CTX_idx| with |X509_STORE_CTX_get_ex_data| to
+// look up the |SSL| from |store_ctx|.
+//
+// WARNING: |callback| is not suitable for implementing custom certificate
+// check, accepting all certificates, or extracting the certificate after
+// verification. It does not replace the default process and is called multiple
+// times throughout that process. It is also very difficult to implement this
+// callback safely, without inadvertently relying on implementation details or
+// making incorrect assumptions about when the callback is called.
+//
+// Instead, use |SSL_set_custom_verify| or |SSL_set_cert_verify_callback| to
+// customize certificate verification. Those callbacks can inspect the peer-sent
+// chain, call |X509_verify_cert| and inspect the result, or perform other
+// operations more straightforwardly.
+OPENSSL_EXPORT void SSL_set_verify(SSL *ssl, int mode,
+                                   int (*callback)(int ok,
+                                                   X509_STORE_CTX *store_ctx));
+
+enum ssl_verify_result_t BORINGSSL_ENUM_INT {
+  ssl_verify_ok,
+  ssl_verify_invalid,
+  ssl_verify_retry,
+};
+
+// SSL_CTX_set_custom_verify configures certificate verification. |mode| is one
+// of the |SSL_VERIFY_*| values defined above. |callback| performs the
+// certificate verification.
+//
+// The callback may call |SSL_get0_peer_certificates| for the certificate chain
+// to validate. The callback should return |ssl_verify_ok| if the certificate is
+// valid. If the certificate is invalid, the callback should return
+// |ssl_verify_invalid| and optionally set |*out_alert| to an alert to send to
+// the peer. Some useful alerts include |SSL_AD_CERTIFICATE_EXPIRED|,
+// |SSL_AD_CERTIFICATE_REVOKED|, |SSL_AD_UNKNOWN_CA|, |SSL_AD_BAD_CERTIFICATE|,
+// |SSL_AD_CERTIFICATE_UNKNOWN|, and |SSL_AD_INTERNAL_ERROR|. See RFC 5246
+// section 7.2.2 for their precise meanings. If unspecified,
+// |SSL_AD_CERTIFICATE_UNKNOWN| will be sent by default.
+//
+// To verify a certificate asynchronously, the callback may return
+// |ssl_verify_retry|. The handshake will then pause with |SSL_get_error|
+// returning |SSL_ERROR_WANT_CERTIFICATE_VERIFY|.
+OPENSSL_EXPORT void SSL_CTX_set_custom_verify(
+    SSL_CTX *ctx, int mode,
+    enum ssl_verify_result_t (*callback)(SSL *ssl, uint8_t *out_alert));
+
+// SSL_set_custom_verify behaves like |SSL_CTX_set_custom_verify| but configures
+// an individual |SSL|.
+OPENSSL_EXPORT void SSL_set_custom_verify(
+    SSL *ssl, int mode,
+    enum ssl_verify_result_t (*callback)(SSL *ssl, uint8_t *out_alert));
+
+// SSL_CTX_get_verify_mode returns |ctx|'s verify mode, set by
+// |SSL_CTX_set_verify|.
+OPENSSL_EXPORT int SSL_CTX_get_verify_mode(const SSL_CTX *ctx);
+
+// SSL_get_verify_mode returns |ssl|'s verify mode, set by |SSL_CTX_set_verify|
+// or |SSL_set_verify|.  It returns -1 on error.
+OPENSSL_EXPORT int SSL_get_verify_mode(const SSL *ssl);
+
+// SSL_CTX_get_verify_callback returns the callback set by
+// |SSL_CTX_set_verify|.
+OPENSSL_EXPORT int (*SSL_CTX_get_verify_callback(const SSL_CTX *ctx))(
+    int ok, X509_STORE_CTX *store_ctx);
+
+// SSL_get_verify_callback returns the callback set by |SSL_CTX_set_verify| or
+// |SSL_set_verify|.
+OPENSSL_EXPORT int (*SSL_get_verify_callback(const SSL *ssl))(
+    int ok, X509_STORE_CTX *store_ctx);
+
+// SSL_set1_host sets a DNS name that will be required to be present in the
+// verified leaf certificate. It returns one on success and zero on error.
+//
+// Note: unless _some_ name checking is performed, certificate validation is
+// ineffective. Simply checking that a host has some certificate from a CA is
+// rarely meaningful—you have to check that the CA believed that the host was
+// who you expect to be talking to.
+//
+// By default, both subject alternative names and the subject's common name
+// attribute are checked. The latter has long been deprecated, so callers should
+// call |SSL_set_hostflags| with |X509_CHECK_FLAG_NEVER_CHECK_SUBJECT| to use
+// the standard behavior. https://crbug.com/boringssl/464 tracks fixing the
+// default.
+OPENSSL_EXPORT int SSL_set1_host(SSL *ssl, const char *hostname);
+
+// SSL_set_hostflags calls |X509_VERIFY_PARAM_set_hostflags| on the
+// |X509_VERIFY_PARAM| associated with this |SSL*|. |flags| should be some
+// combination of the |X509_CHECK_*| constants.
+OPENSSL_EXPORT void SSL_set_hostflags(SSL *ssl, unsigned flags);
+
+// SSL_CTX_set_verify_depth sets the maximum depth of a certificate chain
+// accepted in verification. This count excludes both the target certificate and
+// the trust anchor (root certificate).
+OPENSSL_EXPORT void SSL_CTX_set_verify_depth(SSL_CTX *ctx, int depth);
+
+// SSL_set_verify_depth sets the maximum depth of a certificate chain accepted
+// in verification. This count excludes both the target certificate and the
+// trust anchor (root certificate).
+OPENSSL_EXPORT void SSL_set_verify_depth(SSL *ssl, int depth);
+
+// SSL_CTX_get_verify_depth returns the maximum depth of a certificate accepted
+// in verification.
+OPENSSL_EXPORT int SSL_CTX_get_verify_depth(const SSL_CTX *ctx);
+
+// SSL_get_verify_depth returns the maximum depth of a certificate accepted in
+// verification.
+OPENSSL_EXPORT int SSL_get_verify_depth(const SSL *ssl);
+
+// SSL_CTX_set1_param sets verification parameters from |param|. It returns one
+// on success and zero on failure. The caller retains ownership of |param|.
+OPENSSL_EXPORT int SSL_CTX_set1_param(SSL_CTX *ctx,
+                                      const X509_VERIFY_PARAM *param);
+
+// SSL_set1_param sets verification parameters from |param|. It returns one on
+// success and zero on failure. The caller retains ownership of |param|.
+OPENSSL_EXPORT int SSL_set1_param(SSL *ssl,
+                                  const X509_VERIFY_PARAM *param);
+
+// SSL_CTX_get0_param returns |ctx|'s |X509_VERIFY_PARAM| for certificate
+// verification. The caller must not release the returned pointer but may call
+// functions on it to configure it.
+OPENSSL_EXPORT X509_VERIFY_PARAM *SSL_CTX_get0_param(SSL_CTX *ctx);
+
+// SSL_get0_param returns |ssl|'s |X509_VERIFY_PARAM| for certificate
+// verification. The caller must not release the returned pointer but may call
+// functions on it to configure it.
+OPENSSL_EXPORT X509_VERIFY_PARAM *SSL_get0_param(SSL *ssl);
+
+// SSL_CTX_set_purpose sets |ctx|'s |X509_VERIFY_PARAM|'s 'purpose' parameter to
+// |purpose|. It returns one on success and zero on error.
+OPENSSL_EXPORT int SSL_CTX_set_purpose(SSL_CTX *ctx, int purpose);
+
+// SSL_set_purpose sets |ssl|'s |X509_VERIFY_PARAM|'s 'purpose' parameter to
+// |purpose|. It returns one on success and zero on error.
+OPENSSL_EXPORT int SSL_set_purpose(SSL *ssl, int purpose);
+
+// SSL_CTX_set_trust sets |ctx|'s |X509_VERIFY_PARAM|'s 'trust' parameter to
+// |trust|. It returns one on success and zero on error.
+OPENSSL_EXPORT int SSL_CTX_set_trust(SSL_CTX *ctx, int trust);
+
+// SSL_set_trust sets |ssl|'s |X509_VERIFY_PARAM|'s 'trust' parameter to
+// |trust|. It returns one on success and zero on error.
+OPENSSL_EXPORT int SSL_set_trust(SSL *ssl, int trust);
+
+// SSL_CTX_set_cert_store sets |ctx|'s certificate store to |store|. It takes
+// ownership of |store|. The store is used for certificate verification.
+//
+// The store is also used for the auto-chaining feature, but this is deprecated.
+// See also |SSL_MODE_NO_AUTO_CHAIN|.
+OPENSSL_EXPORT void SSL_CTX_set_cert_store(SSL_CTX *ctx, X509_STORE *store);
+
+// SSL_CTX_get_cert_store returns |ctx|'s certificate store.
+OPENSSL_EXPORT X509_STORE *SSL_CTX_get_cert_store(const SSL_CTX *ctx);
+
+// SSL_CTX_set_default_verify_paths calls |X509_STORE_set_default_paths| on
+// |ctx|'s store. See that function for details.
+//
+// Using this function is not recommended. In OpenSSL, these defaults are
+// determined by OpenSSL's install prefix. There is no corresponding concept for
+// BoringSSL. Future versions of BoringSSL may change or remove this
+// functionality.
+OPENSSL_EXPORT int SSL_CTX_set_default_verify_paths(SSL_CTX *ctx);
+
+// SSL_CTX_load_verify_locations calls |X509_STORE_load_locations| on |ctx|'s
+// store. See that function for details.
+OPENSSL_EXPORT int SSL_CTX_load_verify_locations(SSL_CTX *ctx,
+                                                 const char *ca_file,
+                                                 const char *ca_dir);
+
+// SSL_get_verify_result returns the result of certificate verification. It is
+// either |X509_V_OK| or a |X509_V_ERR_*| value.
+OPENSSL_EXPORT long SSL_get_verify_result(const SSL *ssl);
+
+// SSL_alert_from_verify_result returns the SSL alert code, such as
+// |SSL_AD_CERTIFICATE_EXPIRED|, that corresponds to an |X509_V_ERR_*| value.
+// The return value is always an alert, even when |result| is |X509_V_OK|.
+OPENSSL_EXPORT int SSL_alert_from_verify_result(long result);
+
+// SSL_get_ex_data_X509_STORE_CTX_idx returns the ex_data index used to look up
+// the |SSL| associated with an |X509_STORE_CTX| in the verify callback.
+OPENSSL_EXPORT int SSL_get_ex_data_X509_STORE_CTX_idx(void);
+
+// SSL_CTX_set_cert_verify_callback sets a custom callback to be called on
+// certificate verification rather than |X509_verify_cert|. |store_ctx| contains
+// the verification parameters. The callback should return one on success and
+// zero on fatal error. It may use |X509_STORE_CTX_set_error| to set a
+// verification result.
+//
+// The callback may use |SSL_get_ex_data_X509_STORE_CTX_idx| to recover the
+// |SSL| object from |store_ctx|.
+OPENSSL_EXPORT void SSL_CTX_set_cert_verify_callback(
+    SSL_CTX *ctx, int (*callback)(X509_STORE_CTX *store_ctx, void *arg),
+    void *arg);
+
+// SSL_enable_signed_cert_timestamps causes |ssl| (which must be the client end
+// of a connection) to request SCTs from the server. See
+// https://tools.ietf.org/html/rfc6962.
+//
+// Call |SSL_get0_signed_cert_timestamp_list| to recover the SCT after the
+// handshake.
+OPENSSL_EXPORT void SSL_enable_signed_cert_timestamps(SSL *ssl);
+
+// SSL_CTX_enable_signed_cert_timestamps enables SCT requests on all client SSL
+// objects created from |ctx|.
+//
+// Call |SSL_get0_signed_cert_timestamp_list| to recover the SCT after the
+// handshake.
+OPENSSL_EXPORT void SSL_CTX_enable_signed_cert_timestamps(SSL_CTX *ctx);
+
+// SSL_enable_ocsp_stapling causes |ssl| (which must be the client end of a
+// connection) to request a stapled OCSP response from the server.
+//
+// Call |SSL_get0_ocsp_response| to recover the OCSP response after the
+// handshake.
+OPENSSL_EXPORT void SSL_enable_ocsp_stapling(SSL *ssl);
+
+// SSL_CTX_enable_ocsp_stapling enables OCSP stapling on all client SSL objects
+// created from |ctx|.
+//
+// Call |SSL_get0_ocsp_response| to recover the OCSP response after the
+// handshake.
+OPENSSL_EXPORT void SSL_CTX_enable_ocsp_stapling(SSL_CTX *ctx);
+
+// SSL_CTX_set0_verify_cert_store sets an |X509_STORE| that will be used
+// exclusively for certificate verification and returns one. Ownership of
+// |store| is transferred to the |SSL_CTX|.
+OPENSSL_EXPORT int SSL_CTX_set0_verify_cert_store(SSL_CTX *ctx,
+                                                  X509_STORE *store);
+
+// SSL_CTX_set1_verify_cert_store sets an |X509_STORE| that will be used
+// exclusively for certificate verification and returns one. An additional
+// reference to |store| will be taken.
+OPENSSL_EXPORT int SSL_CTX_set1_verify_cert_store(SSL_CTX *ctx,
+                                                  X509_STORE *store);
+
+// SSL_set0_verify_cert_store sets an |X509_STORE| that will be used
+// exclusively for certificate verification and returns one. Ownership of
+// |store| is transferred to the |SSL|.
+OPENSSL_EXPORT int SSL_set0_verify_cert_store(SSL *ssl, X509_STORE *store);
+
+// SSL_set1_verify_cert_store sets an |X509_STORE| that will be used
+// exclusively for certificate verification and returns one. An additional
+// reference to |store| will be taken.
+OPENSSL_EXPORT int SSL_set1_verify_cert_store(SSL *ssl, X509_STORE *store);
+
+// SSL_CTX_set_verify_algorithm_prefs configures |ctx| to use |prefs| as the
+// preference list when verifying signatures from the peer's long-term key. It
+// returns one on zero on error. |prefs| should not include the internal-only
+// value |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
+OPENSSL_EXPORT int SSL_CTX_set_verify_algorithm_prefs(SSL_CTX *ctx,
+                                                      const uint16_t *prefs,
+                                                      size_t num_prefs);
+
+// SSL_set_verify_algorithm_prefs configures |ssl| to use |prefs| as the
+// preference list when verifying signatures from the peer's long-term key. It
+// returns one on zero on error. |prefs| should not include the internal-only
+// value |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
+OPENSSL_EXPORT int SSL_set_verify_algorithm_prefs(SSL *ssl,
+                                                  const uint16_t *prefs,
+                                                  size_t num_prefs);
+
+
+// Client certificate CA list.
+//
+// When requesting a client certificate, a server may advertise a list of
+// certificate authorities which are accepted. These functions may be used to
+// configure this list.
+
+// SSL_set_client_CA_list sets |ssl|'s client certificate CA list to
+// |name_list|. It takes ownership of |name_list|.
+OPENSSL_EXPORT void SSL_set_client_CA_list(SSL *ssl,
+                                           STACK_OF(X509_NAME) *name_list);
+
+// SSL_CTX_set_client_CA_list sets |ctx|'s client certificate CA list to
+// |name_list|. It takes ownership of |name_list|.
+OPENSSL_EXPORT void SSL_CTX_set_client_CA_list(SSL_CTX *ctx,
+                                               STACK_OF(X509_NAME) *name_list);
+
+// SSL_set0_client_CAs sets |ssl|'s client certificate CA list to |name_list|,
+// which should contain DER-encoded distinguished names (RFC 5280). It takes
+// ownership of |name_list|.
+OPENSSL_EXPORT void SSL_set0_client_CAs(SSL *ssl,
+                                        STACK_OF(CRYPTO_BUFFER) *name_list);
+
+// SSL_CTX_set0_client_CAs sets |ctx|'s client certificate CA list to
+// |name_list|, which should contain DER-encoded distinguished names (RFC 5280).
+// It takes ownership of |name_list|.
+OPENSSL_EXPORT void SSL_CTX_set0_client_CAs(SSL_CTX *ctx,
+                                            STACK_OF(CRYPTO_BUFFER) *name_list);
+
+// SSL_get_client_CA_list returns |ssl|'s client certificate CA list. If |ssl|
+// has not been configured as a client, this is the list configured by
+// |SSL_CTX_set_client_CA_list|.
+//
+// If configured as a client, it returns the client certificate CA list sent by
+// the server. In this mode, the behavior is undefined except during the
+// callbacks set by |SSL_CTX_set_cert_cb| and |SSL_CTX_set_client_cert_cb| or
+// when the handshake is paused because of them.
+OPENSSL_EXPORT STACK_OF(X509_NAME) *SSL_get_client_CA_list(const SSL *ssl);
+
+// SSL_get0_server_requested_CAs returns the CAs sent by a server to guide a
+// client in certificate selection. They are a series of DER-encoded X.509
+// names. This function may only be called during a callback set by
+// |SSL_CTX_set_cert_cb| or when the handshake is paused because of it.
+//
+// The returned stack is owned by |ssl|, as are its contents. It should not be
+// used past the point where the handshake is restarted after the callback.
+OPENSSL_EXPORT const STACK_OF(CRYPTO_BUFFER) *
+    SSL_get0_server_requested_CAs(const SSL *ssl);
+
+// SSL_CTX_get_client_CA_list returns |ctx|'s client certificate CA list.
+OPENSSL_EXPORT STACK_OF(X509_NAME) *
+    SSL_CTX_get_client_CA_list(const SSL_CTX *ctx);
+
+// SSL_add_client_CA appends |x509|'s subject to the client certificate CA list.
+// It returns one on success or zero on error. The caller retains ownership of
+// |x509|.
+OPENSSL_EXPORT int SSL_add_client_CA(SSL *ssl, X509 *x509);
+
+// SSL_CTX_add_client_CA appends |x509|'s subject to the client certificate CA
+// list. It returns one on success or zero on error. The caller retains
+// ownership of |x509|.
+OPENSSL_EXPORT int SSL_CTX_add_client_CA(SSL_CTX *ctx, X509 *x509);
+
+// SSL_load_client_CA_file opens |file| and reads PEM-encoded certificates from
+// it. It returns a newly-allocated stack of the certificate subjects or NULL
+// on error. Duplicates in |file| are ignored.
+OPENSSL_EXPORT STACK_OF(X509_NAME) *SSL_load_client_CA_file(const char *file);
+
+// SSL_dup_CA_list makes a deep copy of |list|. It returns the new list on
+// success or NULL on allocation error.
+OPENSSL_EXPORT STACK_OF(X509_NAME) *SSL_dup_CA_list(STACK_OF(X509_NAME) *list);
+
+// SSL_add_file_cert_subjects_to_stack behaves like |SSL_load_client_CA_file|
+// but appends the result to |out|. It returns one on success or zero on
+// error.
+OPENSSL_EXPORT int SSL_add_file_cert_subjects_to_stack(STACK_OF(X509_NAME) *out,
+                                                       const char *file);
+
+// SSL_add_bio_cert_subjects_to_stack behaves like
+// |SSL_add_file_cert_subjects_to_stack| but reads from |bio|.
+OPENSSL_EXPORT int SSL_add_bio_cert_subjects_to_stack(STACK_OF(X509_NAME) *out,
+                                                      BIO *bio);
+
+
+// Server name indication.
+//
+// The server_name extension (RFC 3546) allows the client to advertise the name
+// of the server it is connecting to. This is used in virtual hosting
+// deployments to select one of a several certificates on a single IP. Only the
+// host_name name type is supported.
+
+#define TLSEXT_NAMETYPE_host_name 0
+
+// SSL_set_tlsext_host_name, for a client, configures |ssl| to advertise |name|
+// in the server_name extension. It returns one on success and zero on error.
+OPENSSL_EXPORT int SSL_set_tlsext_host_name(SSL *ssl, const char *name);
+
+// SSL_get_servername, for a server, returns the hostname supplied by the
+// client or NULL if there was none. The |type| argument must be
+// |TLSEXT_NAMETYPE_host_name|.
+OPENSSL_EXPORT const char *SSL_get_servername(const SSL *ssl, const int type);
+
+// SSL_get_servername_type, for a server, returns |TLSEXT_NAMETYPE_host_name|
+// if the client sent a hostname and -1 otherwise.
+OPENSSL_EXPORT int SSL_get_servername_type(const SSL *ssl);
+
+// SSL_CTX_set_tlsext_servername_callback configures |callback| to be called on
+// the server after ClientHello extensions have been parsed and returns one.
+// The callback may use |SSL_get_servername| to examine the server_name
+// extension and returns a |SSL_TLSEXT_ERR_*| value. The value of |arg| may be
+// set by calling |SSL_CTX_set_tlsext_servername_arg|.
+//
+// If the callback returns |SSL_TLSEXT_ERR_NOACK|, the server_name extension is
+// not acknowledged in the ServerHello. If the return value is
+// |SSL_TLSEXT_ERR_ALERT_FATAL|, then |*out_alert| is the alert to send,
+// defaulting to |SSL_AD_UNRECOGNIZED_NAME|. |SSL_TLSEXT_ERR_ALERT_WARNING| is
+// ignored and treated as |SSL_TLSEXT_ERR_OK|.
+OPENSSL_EXPORT int SSL_CTX_set_tlsext_servername_callback(
+    SSL_CTX *ctx, int (*callback)(SSL *ssl, int *out_alert, void *arg));
+
+// SSL_CTX_set_tlsext_servername_arg sets the argument to the servername
+// callback and returns one. See |SSL_CTX_set_tlsext_servername_callback|.
+OPENSSL_EXPORT int SSL_CTX_set_tlsext_servername_arg(SSL_CTX *ctx, void *arg);
+
+// SSL_TLSEXT_ERR_* are values returned by some extension-related callbacks.
+#define SSL_TLSEXT_ERR_OK 0
+#define SSL_TLSEXT_ERR_ALERT_WARNING 1
+#define SSL_TLSEXT_ERR_ALERT_FATAL 2
+#define SSL_TLSEXT_ERR_NOACK 3
+
+// SSL_set_SSL_CTX changes |ssl|'s |SSL_CTX|. |ssl| will use the
+// certificate-related settings from |ctx|, and |SSL_get_SSL_CTX| will report
+// |ctx|. This function may be used during the callbacks registered by
+// |SSL_CTX_set_select_certificate_cb|,
+// |SSL_CTX_set_tlsext_servername_callback|, and |SSL_CTX_set_cert_cb| or when
+// the handshake is paused from them. It is typically used to switch
+// certificates based on SNI.
+//
+// Note the session cache and related settings will continue to use the initial
+// |SSL_CTX|. Callers should use |SSL_CTX_set_session_id_context| to partition
+// the session cache between different domains.
+//
+// TODO(davidben): Should other settings change after this call?
+OPENSSL_EXPORT SSL_CTX *SSL_set_SSL_CTX(SSL *ssl, SSL_CTX *ctx);
+
+
+// Application-layer protocol negotiation.
+//
+// The ALPN extension (RFC 7301) allows negotiating different application-layer
+// protocols over a single port. This is used, for example, to negotiate
+// HTTP/2.
+
+// SSL_CTX_set_alpn_protos sets the client ALPN protocol list on |ctx| to
+// |protos|. |protos| must be in wire-format (i.e. a series of non-empty, 8-bit
+// length-prefixed strings), or the empty string to disable ALPN. It returns
+// zero on success and one on failure. Configuring a non-empty string enables
+// ALPN on a client.
+//
+// WARNING: this function is dangerous because it breaks the usual return value
+// convention.
+OPENSSL_EXPORT int SSL_CTX_set_alpn_protos(SSL_CTX *ctx, const uint8_t *protos,
+                                           size_t protos_len);
+
+// SSL_set_alpn_protos sets the client ALPN protocol list on |ssl| to |protos|.
+// |protos| must be in wire-format (i.e. a series of non-empty, 8-bit
+// length-prefixed strings), or the empty string to disable ALPN. It returns
+// zero on success and one on failure. Configuring a non-empty string enables
+// ALPN on a client.
+//
+// WARNING: this function is dangerous because it breaks the usual return value
+// convention.
+OPENSSL_EXPORT int SSL_set_alpn_protos(SSL *ssl, const uint8_t *protos,
+                                       size_t protos_len);
+
+// SSL_CTX_set_alpn_select_cb sets a callback function on |ctx| that is called
+// during ClientHello processing in order to select an ALPN protocol from the
+// client's list of offered protocols.
+//
+// The callback is passed a wire-format (i.e. a series of non-empty, 8-bit
+// length-prefixed strings) ALPN protocol list in |in|. To select a protocol,
+// the callback should set |*out| and |*out_len| to the selected protocol and
+// return |SSL_TLSEXT_ERR_OK| on success. It does not pass ownership of the
+// buffer, so |*out| should point to a static string, a buffer that outlives the
+// callback call, or the corresponding entry in |in|.
+//
+// If the server supports ALPN, but there are no protocols in common, the
+// callback should return |SSL_TLSEXT_ERR_ALERT_FATAL| to abort the connection
+// with a no_application_protocol alert.
+//
+// If the server does not support ALPN, it can return |SSL_TLSEXT_ERR_NOACK| to
+// continue the handshake without negotiating a protocol. This may be useful if
+// multiple server configurations share an |SSL_CTX|, only some of which have
+// ALPN protocols configured.
+//
+// |SSL_TLSEXT_ERR_ALERT_WARNING| is ignored and will be treated as
+// |SSL_TLSEXT_ERR_NOACK|.
+//
+// The callback will only be called if the client supports ALPN. Callers that
+// wish to require ALPN for all clients must check |SSL_get0_alpn_selected|
+// after the handshake. In QUIC connections, this is done automatically.
+//
+// The cipher suite is selected before negotiating ALPN. The callback may use
+// |SSL_get_pending_cipher| to query the cipher suite. This may be used to
+// implement HTTP/2's cipher suite constraints.
+OPENSSL_EXPORT void SSL_CTX_set_alpn_select_cb(
+    SSL_CTX *ctx, int (*cb)(SSL *ssl, const uint8_t **out, uint8_t *out_len,
+                            const uint8_t *in, unsigned in_len, void *arg),
+    void *arg);
+
+// SSL_get0_alpn_selected gets the selected ALPN protocol (if any) from |ssl|.
+// On return it sets |*out_data| to point to |*out_len| bytes of protocol name
+// (not including the leading length-prefix byte). If the server didn't respond
+// with a negotiated protocol then |*out_len| will be zero.
+OPENSSL_EXPORT void SSL_get0_alpn_selected(const SSL *ssl,
+                                           const uint8_t **out_data,
+                                           unsigned *out_len);
+
+// SSL_CTX_set_allow_unknown_alpn_protos configures client connections on |ctx|
+// to allow unknown ALPN protocols from the server. Otherwise, by default, the
+// client will require that the protocol be advertised in
+// |SSL_CTX_set_alpn_protos|.
+OPENSSL_EXPORT void SSL_CTX_set_allow_unknown_alpn_protos(SSL_CTX *ctx,
+                                                          int enabled);
+
+
+// Application-layer protocol settings
+//
+// The ALPS extension (draft-vvv-tls-alps) allows exchanging application-layer
+// settings in the TLS handshake for applications negotiated with ALPN. Note
+// that, when ALPS is negotiated, the client and server each advertise their own
+// settings, so there are functions to both configure setting to send and query
+// received settings.
+
+// SSL_add_application_settings configures |ssl| to enable ALPS with ALPN
+// protocol |proto|, sending an ALPS value of |settings|. It returns one on
+// success and zero on error. If |proto| is negotiated via ALPN and the peer
+// supports ALPS, |settings| will be sent to the peer. The peer's ALPS value can
+// be retrieved with |SSL_get0_peer_application_settings|.
+//
+// On the client, this function should be called before the handshake, once for
+// each supported ALPN protocol which uses ALPS. |proto| must be included in the
+// client's ALPN configuration (see |SSL_CTX_set_alpn_protos| and
+// |SSL_set_alpn_protos|). On the server, ALPS can be preconfigured for each
+// protocol as in the client, or configuration can be deferred to the ALPN
+// callback (see |SSL_CTX_set_alpn_select_cb|), in which case only the selected
+// protocol needs to be configured.
+//
+// ALPS can be independently configured from 0-RTT, however changes in protocol
+// settings will fallback to 1-RTT to negotiate the new value, so it is
+// recommended for |settings| to be relatively stable.
+OPENSSL_EXPORT int SSL_add_application_settings(SSL *ssl, const uint8_t *proto,
+                                                size_t proto_len,
+                                                const uint8_t *settings,
+                                                size_t settings_len);
+
+// SSL_get0_peer_application_settings sets |*out_data| and |*out_len| to a
+// buffer containing the peer's ALPS value, or the empty string if ALPS was not
+// negotiated. Note an empty string could also indicate the peer sent an empty
+// settings value. Use |SSL_has_application_settings| to check if ALPS was
+// negotiated. The output buffer is owned by |ssl| and is valid until the next
+// time |ssl| is modified.
+OPENSSL_EXPORT void SSL_get0_peer_application_settings(const SSL *ssl,
+                                                       const uint8_t **out_data,
+                                                       size_t *out_len);
+
+// SSL_has_application_settings returns one if ALPS was negotiated on this
+// connection and zero otherwise.
+OPENSSL_EXPORT int SSL_has_application_settings(const SSL *ssl);
+
+// SSL_set_alps_use_new_codepoint configures whether to use the new ALPS
+// codepoint. By default, the old codepoint is used.
+OPENSSL_EXPORT void SSL_set_alps_use_new_codepoint(SSL *ssl, int use_new);
+
+
+// Certificate compression.
+//
+// Certificates in TLS 1.3 can be compressed (RFC 8879). BoringSSL supports this
+// as both a client and a server, but does not link against any specific
+// compression libraries in order to keep dependencies to a minimum. Instead,
+// hooks for compression and decompression can be installed in an |SSL_CTX| to
+// enable support.
+
+// ssl_cert_compression_func_t is a pointer to a function that performs
+// compression. It must write the compressed representation of |in| to |out|,
+// returning one on success and zero on error. The results of compressing
+// certificates are not cached internally. Implementations may wish to implement
+// their own cache if they expect it to be useful given the certificates that
+// they serve.
+typedef int (*ssl_cert_compression_func_t)(SSL *ssl, CBB *out,
+                                           const uint8_t *in, size_t in_len);
+
+// ssl_cert_decompression_func_t is a pointer to a function that performs
+// decompression. The compressed data from the peer is passed as |in| and the
+// decompressed result must be exactly |uncompressed_len| bytes long. It returns
+// one on success, in which case |*out| must be set to the result of
+// decompressing |in|, or zero on error. Setting |*out| transfers ownership,
+// i.e. |CRYPTO_BUFFER_free| will be called on |*out| at some point in the
+// future. The results of decompressions are not cached internally.
+// Implementations may wish to implement their own cache if they expect it to be
+// useful.
+typedef int (*ssl_cert_decompression_func_t)(SSL *ssl, CRYPTO_BUFFER **out,
+                                             size_t uncompressed_len,
+                                             const uint8_t *in, size_t in_len);
+
+// SSL_CTX_add_cert_compression_alg registers a certificate compression
+// algorithm on |ctx| with ID |alg_id|. (The value of |alg_id| should be an IANA
+// assigned value and each can only be registered once.)
+//
+// One of the function pointers may be NULL to avoid having to implement both
+// sides of a compression algorithm if you're only going to use it in one
+// direction. In this case, the unimplemented direction acts like it was never
+// configured.
+//
+// For a server, algorithms are registered in preference order with the most
+// preferable first. It returns one on success or zero on error.
+OPENSSL_EXPORT int SSL_CTX_add_cert_compression_alg(
+    SSL_CTX *ctx, uint16_t alg_id, ssl_cert_compression_func_t compress,
+    ssl_cert_decompression_func_t decompress);
+
+
+// Next protocol negotiation.
+//
+// The NPN extension (draft-agl-tls-nextprotoneg-03) is the predecessor to ALPN
+// and deprecated in favor of it.
+
+// SSL_CTX_set_next_protos_advertised_cb sets a callback that is called when a
+// TLS server needs a list of supported protocols for Next Protocol
+// Negotiation. The returned list must be in wire format. The list is returned
+// by setting |*out| to point to it and |*out_len| to its length. This memory
+// will not be modified, but one should assume that |ssl| keeps a reference to
+// it.
+//
+// The callback should return |SSL_TLSEXT_ERR_OK| if it wishes to advertise.
+// Otherwise, no such extension will be included in the ServerHello.
+OPENSSL_EXPORT void SSL_CTX_set_next_protos_advertised_cb(
+    SSL_CTX *ctx,
+    int (*cb)(SSL *ssl, const uint8_t **out, unsigned *out_len, void *arg),
+    void *arg);
+
+// SSL_CTX_set_next_proto_select_cb sets a callback that is called when a client
+// needs to select a protocol from the server's provided list. |*out| must be
+// set to point to the selected protocol (which may be within |in|). The length
+// of the protocol name must be written into |*out_len|. The server's advertised
+// protocols are provided in |in| and |in_len|. The callback can assume that
+// |in| is syntactically valid.
+//
+// The client must select a protocol. It is fatal to the connection if this
+// callback returns a value other than |SSL_TLSEXT_ERR_OK|.
+//
+// Configuring this callback enables NPN on a client.
+OPENSSL_EXPORT void SSL_CTX_set_next_proto_select_cb(
+    SSL_CTX *ctx, int (*cb)(SSL *ssl, uint8_t **out, uint8_t *out_len,
+                            const uint8_t *in, unsigned in_len, void *arg),
+    void *arg);
+
+// SSL_get0_next_proto_negotiated sets |*out_data| and |*out_len| to point to
+// the client's requested protocol for this connection. If the client didn't
+// request any protocol, then |*out_data| is set to NULL.
+//
+// Note that the client can request any protocol it chooses. The value returned
+// from this function need not be a member of the list of supported protocols
+// provided by the server.
+OPENSSL_EXPORT void SSL_get0_next_proto_negotiated(const SSL *ssl,
+                                                   const uint8_t **out_data,
+                                                   unsigned *out_len);
+
+// SSL_select_next_proto implements the standard protocol selection. It is
+// expected that this function is called from the callback set by
+// |SSL_CTX_set_next_proto_select_cb|.
+//
+// |peer| and |supported| must be vectors of 8-bit, length-prefixed byte strings
+// containing the peer and locally-configured protocols, respectively. The
+// length byte itself is not included in the length. A byte string of length 0
+// is invalid. No byte string may be truncated. |supported| is assumed to be
+// non-empty.
+//
+// This function finds the first protocol in |peer| which is also in
+// |supported|. If one was found, it sets |*out| and |*out_len| to point to it
+// and returns |OPENSSL_NPN_NEGOTIATED|. Otherwise, it returns
+// |OPENSSL_NPN_NO_OVERLAP| and sets |*out| and |*out_len| to the first
+// supported protocol.
+OPENSSL_EXPORT int SSL_select_next_proto(uint8_t **out, uint8_t *out_len,
+                                         const uint8_t *peer, unsigned peer_len,
+                                         const uint8_t *supported,
+                                         unsigned supported_len);
+
+#define OPENSSL_NPN_UNSUPPORTED 0
+#define OPENSSL_NPN_NEGOTIATED 1
+#define OPENSSL_NPN_NO_OVERLAP 2
+
+
+// Channel ID.
+//
+// See draft-balfanz-tls-channelid-01. This is an old, experimental mechanism
+// and should not be used in new code.
+
+// SSL_CTX_set_tls_channel_id_enabled configures whether connections associated
+// with |ctx| should enable Channel ID as a server.
+OPENSSL_EXPORT void SSL_CTX_set_tls_channel_id_enabled(SSL_CTX *ctx,
+                                                       int enabled);
+
+// SSL_set_tls_channel_id_enabled configures whether |ssl| should enable Channel
+// ID as a server.
+OPENSSL_EXPORT void SSL_set_tls_channel_id_enabled(SSL *ssl, int enabled);
+
+// SSL_CTX_set1_tls_channel_id configures a TLS client to send a TLS Channel ID
+// to compatible servers. |private_key| must be a P-256 EC key. It returns one
+// on success and zero on error.
+OPENSSL_EXPORT int SSL_CTX_set1_tls_channel_id(SSL_CTX *ctx,
+                                               EVP_PKEY *private_key);
+
+// SSL_set1_tls_channel_id configures a TLS client to send a TLS Channel ID to
+// compatible servers. |private_key| must be a P-256 EC key. It returns one on
+// success and zero on error.
+OPENSSL_EXPORT int SSL_set1_tls_channel_id(SSL *ssl, EVP_PKEY *private_key);
+
+// SSL_get_tls_channel_id gets the client's TLS Channel ID from a server |SSL|
+// and copies up to the first |max_out| bytes into |out|. The Channel ID
+// consists of the client's P-256 public key as an (x,y) pair where each is a
+// 32-byte, big-endian field element. It returns 0 if the client didn't offer a
+// Channel ID and the length of the complete Channel ID otherwise. This function
+// always returns zero if |ssl| is a client.
+OPENSSL_EXPORT size_t SSL_get_tls_channel_id(SSL *ssl, uint8_t *out,
+                                             size_t max_out);
+
+
+// DTLS-SRTP.
+//
+// See RFC 5764.
+
+// srtp_protection_profile_st (aka |SRTP_PROTECTION_PROFILE|) is an SRTP
+// profile for use with the use_srtp extension.
+struct srtp_protection_profile_st {
+  const char *name;
+  unsigned long id;
+} /* SRTP_PROTECTION_PROFILE */;
+
+DEFINE_CONST_STACK_OF(SRTP_PROTECTION_PROFILE)
+
+// SRTP_* define constants for SRTP profiles.
+#define SRTP_AES128_CM_SHA1_80 0x0001
+#define SRTP_AES128_CM_SHA1_32 0x0002
+#define SRTP_AES128_F8_SHA1_80 0x0003
+#define SRTP_AES128_F8_SHA1_32 0x0004
+#define SRTP_NULL_SHA1_80      0x0005
+#define SRTP_NULL_SHA1_32      0x0006
+#define SRTP_AEAD_AES_128_GCM  0x0007
+#define SRTP_AEAD_AES_256_GCM  0x0008
+
+// SSL_CTX_set_srtp_profiles enables SRTP for all SSL objects created from
+// |ctx|. |profile| contains a colon-separated list of profile names. It returns
+// one on success and zero on failure.
+OPENSSL_EXPORT int SSL_CTX_set_srtp_profiles(SSL_CTX *ctx,
+                                             const char *profiles);
+
+// SSL_set_srtp_profiles enables SRTP for |ssl|.  |profile| contains a
+// colon-separated list of profile names. It returns one on success and zero on
+// failure.
+OPENSSL_EXPORT int SSL_set_srtp_profiles(SSL *ssl, const char *profiles);
+
+// SSL_get_srtp_profiles returns the SRTP profiles supported by |ssl|.
+OPENSSL_EXPORT const STACK_OF(SRTP_PROTECTION_PROFILE) *SSL_get_srtp_profiles(
+    const SSL *ssl);
+
+// SSL_get_selected_srtp_profile returns the selected SRTP profile, or NULL if
+// SRTP was not negotiated.
+OPENSSL_EXPORT const SRTP_PROTECTION_PROFILE *SSL_get_selected_srtp_profile(
+    SSL *ssl);
+
+
+// Pre-shared keys.
+//
+// Connections may be configured with PSK (Pre-Shared Key) cipher suites. These
+// authenticate using out-of-band pre-shared keys rather than certificates. See
+// RFC 4279.
+//
+// This implementation uses NUL-terminated C strings for identities and identity
+// hints, so values with a NUL character are not supported. (RFC 4279 does not
+// specify the format of an identity.)
+
+// PSK_MAX_IDENTITY_LEN is the maximum supported length of a PSK identity,
+// excluding the NUL terminator.
+#define PSK_MAX_IDENTITY_LEN 128
+
+// PSK_MAX_PSK_LEN is the maximum supported length of a pre-shared key.
+#define PSK_MAX_PSK_LEN 256
+
+// SSL_CTX_set_psk_client_callback sets the callback to be called when PSK is
+// negotiated on the client. This callback must be set to enable PSK cipher
+// suites on the client.
+//
+// The callback is passed the identity hint in |hint| or NULL if none was
+// provided. It should select a PSK identity and write the identity and the
+// corresponding PSK to |identity| and |psk|, respectively. The identity is
+// written as a NUL-terminated C string of length (excluding the NUL terminator)
+// at most |max_identity_len|. The PSK's length must be at most |max_psk_len|.
+// The callback returns the length of the PSK or 0 if no suitable identity was
+// found.
+OPENSSL_EXPORT void SSL_CTX_set_psk_client_callback(
+    SSL_CTX *ctx, unsigned (*cb)(SSL *ssl, const char *hint, char *identity,
+                                 unsigned max_identity_len, uint8_t *psk,
+                                 unsigned max_psk_len));
+
+// SSL_set_psk_client_callback sets the callback to be called when PSK is
+// negotiated on the client. This callback must be set to enable PSK cipher
+// suites on the client. See also |SSL_CTX_set_psk_client_callback|.
+OPENSSL_EXPORT void SSL_set_psk_client_callback(
+    SSL *ssl, unsigned (*cb)(SSL *ssl, const char *hint, char *identity,
+                             unsigned max_identity_len, uint8_t *psk,
+                             unsigned max_psk_len));
+
+// SSL_CTX_set_psk_server_callback sets the callback to be called when PSK is
+// negotiated on the server. This callback must be set to enable PSK cipher
+// suites on the server.
+//
+// The callback is passed the identity in |identity|. It should write a PSK of
+// length at most |max_psk_len| to |psk| and return the number of bytes written
+// or zero if the PSK identity is unknown.
+OPENSSL_EXPORT void SSL_CTX_set_psk_server_callback(
+    SSL_CTX *ctx, unsigned (*cb)(SSL *ssl, const char *identity, uint8_t *psk,
+                                 unsigned max_psk_len));
+
+// SSL_set_psk_server_callback sets the callback to be called when PSK is
+// negotiated on the server. This callback must be set to enable PSK cipher
+// suites on the server. See also |SSL_CTX_set_psk_server_callback|.
+OPENSSL_EXPORT void SSL_set_psk_server_callback(
+    SSL *ssl, unsigned (*cb)(SSL *ssl, const char *identity, uint8_t *psk,
+                             unsigned max_psk_len));
+
+// SSL_CTX_use_psk_identity_hint configures server connections to advertise an
+// identity hint of |identity_hint|. It returns one on success and zero on
+// error.
+OPENSSL_EXPORT int SSL_CTX_use_psk_identity_hint(SSL_CTX *ctx,
+                                                 const char *identity_hint);
+
+// SSL_use_psk_identity_hint configures server connections to advertise an
+// identity hint of |identity_hint|. It returns one on success and zero on
+// error.
+OPENSSL_EXPORT int SSL_use_psk_identity_hint(SSL *ssl,
+                                             const char *identity_hint);
+
+// SSL_get_psk_identity_hint returns the PSK identity hint advertised for |ssl|
+// or NULL if there is none.
+OPENSSL_EXPORT const char *SSL_get_psk_identity_hint(const SSL *ssl);
+
+// SSL_get_psk_identity, after the handshake completes, returns the PSK identity
+// that was negotiated by |ssl| or NULL if PSK was not used.
+OPENSSL_EXPORT const char *SSL_get_psk_identity(const SSL *ssl);
+
+
+// Delegated credentials.
+//
+// Delegated credentials (RFC 9345) allow a TLS 1.3 endpoint to use its
+// certificate to issue new credentials for authentication. Once issued,
+// credentials can't be revoked. In order to mitigate the damage in case the
+// credential secret key is compromised, the credential is only valid for a
+// short time (days, hours, or even minutes).
+//
+// Currently only the authenticating side, as a server, is implemented. To
+// authenticate with delegated credentials, construct an |SSL_CREDENTIAL| with
+// |SSL_CREDENTIAL_new_delegated| and add it to the credential list. See also
+// |SSL_CTX_add1_credential|. Callers may configure a mix of delegated
+// credentials and X.509 credentials on the same |SSL| or |SSL_CTX| to support a
+// range of clients.
+
+// SSL_CREDENTIAL_new_delegated returns a new, empty delegated credential, or
+// NULL on error. Callers should release the result with |SSL_CREDENTIAL_free|
+// when done.
+//
+// Callers should configure a delegated credential, certificate chain and
+// private key on the credential, along with other properties, then add it with
+// |SSL_CTX_add1_credential|.
+OPENSSL_EXPORT SSL_CREDENTIAL *SSL_CREDENTIAL_new_delegated(void);
+
+// SSL_CREDENTIAL_set1_delegated_credential sets |cred|'s delegated credentials
+// structure to |dc|. It returns one on success and zero on error, including if
+// |dc| is malformed. This should be a DelegatedCredential structure, signed by
+// the end-entity certificate, as described in RFC 9345.
+OPENSSL_EXPORT int SSL_CREDENTIAL_set1_delegated_credential(
+    SSL_CREDENTIAL *cred, CRYPTO_BUFFER *dc);
+
+
+// QUIC integration.
+//
+// QUIC acts as an underlying transport for the TLS 1.3 handshake. The following
+// functions allow a QUIC implementation to serve as the underlying transport as
+// described in RFC 9001.
+//
+// When configured for QUIC, |SSL_do_handshake| will drive the handshake as
+// before, but it will not use the configured |BIO|. It will call functions on
+// |SSL_QUIC_METHOD| to configure secrets and send data. If data is needed from
+// the peer, it will return |SSL_ERROR_WANT_READ|. As the caller receives data
+// it can decrypt, it calls |SSL_provide_quic_data|. Subsequent
+// |SSL_do_handshake| calls will then consume that data and progress the
+// handshake. After the handshake is complete, the caller should continue to
+// call |SSL_provide_quic_data| for any post-handshake data, followed by
+// |SSL_process_quic_post_handshake| to process it. It is an error to call
+// |SSL_read| and |SSL_write| in QUIC.
+//
+// 0-RTT behaves similarly to |TLS_method|'s usual behavior. |SSL_do_handshake|
+// returns early as soon as the client (respectively, server) is allowed to send
+// 0-RTT (respectively, half-RTT) data. The caller should then call
+// |SSL_do_handshake| again to consume the remaining handshake messages and
+// confirm the handshake. As a client, |SSL_ERROR_EARLY_DATA_REJECTED| and
+// |SSL_reset_early_data_reject| behave as usual.
+//
+// See https://www.rfc-editor.org/rfc/rfc9001.html#section-4.1 for more details.
+//
+// To avoid DoS attacks, the QUIC implementation must limit the amount of data
+// being queued up. The implementation can call
+// |SSL_quic_max_handshake_flight_len| to get the maximum buffer length at each
+// encryption level.
+//
+// QUIC implementations must additionally configure transport parameters with
+// |SSL_set_quic_transport_params|. |SSL_get_peer_quic_transport_params| may be
+// used to query the value received from the peer. BoringSSL handles this
+// extension as an opaque byte string. The caller is responsible for serializing
+// and parsing them. See https://www.rfc-editor.org/rfc/rfc9000#section-7.4 for
+// details.
+//
+// QUIC additionally imposes restrictions on 0-RTT. In particular, the QUIC
+// transport layer requires that if a server accepts 0-RTT data, then the
+// transport parameters sent on the resumed connection must not lower any limits
+// compared to the transport parameters that the server sent on the connection
+// where the ticket for 0-RTT was issued. In effect, the server must remember
+// the transport parameters with the ticket. Application protocols running on
+// QUIC may impose similar restrictions, for example HTTP/3's restrictions on
+// SETTINGS frames.
+//
+// BoringSSL implements this check by doing a byte-for-byte comparison of an
+// opaque context passed in by the server. This context must be the same on the
+// connection where the ticket was issued and the connection where that ticket
+// is used for 0-RTT. If there is a mismatch, or the context was not set,
+// BoringSSL will reject early data (but not reject the resumption attempt).
+// This context is set via |SSL_set_quic_early_data_context| and should cover
+// both transport parameters and any application state.
+// |SSL_set_quic_early_data_context| must be called on the server with a
+// non-empty context if the server is to support 0-RTT in QUIC.
+//
+// BoringSSL does not perform any client-side checks on the transport
+// parameters received from a server that also accepted early data. It is up to
+// the caller to verify that the received transport parameters do not lower any
+// limits, and to close the QUIC connection if that is not the case. The same
+// holds for any application protocol state remembered for 0-RTT, e.g. HTTP/3
+// SETTINGS.
+
+// ssl_encryption_level_t represents a specific QUIC encryption level used to
+// transmit handshake messages.
+enum ssl_encryption_level_t BORINGSSL_ENUM_INT {
+  ssl_encryption_initial = 0,
+  ssl_encryption_early_data,
+  ssl_encryption_handshake,
+  ssl_encryption_application,
+};
+
+// ssl_quic_method_st (aka |SSL_QUIC_METHOD|) describes custom QUIC hooks.
+struct ssl_quic_method_st {
+  // set_read_secret configures the read secret and cipher suite for the given
+  // encryption level. It returns one on success and zero to terminate the
+  // handshake with an error. It will be called at most once per encryption
+  // level.
+  //
+  // BoringSSL will not release read keys before QUIC may use them. Once a level
+  // has been initialized, QUIC may begin processing data from it. Handshake
+  // data should be passed to |SSL_provide_quic_data| and application data (if
+  // |level| is |ssl_encryption_early_data| or |ssl_encryption_application|) may
+  // be processed according to the rules of the QUIC protocol.
+  //
+  // QUIC ACKs packets at the same encryption level they were received at,
+  // except that client |ssl_encryption_early_data| (0-RTT) packets trigger
+  // server |ssl_encryption_application| (1-RTT) ACKs. BoringSSL will always
+  // install ACK-writing keys with |set_write_secret| before the packet-reading
+  // keys with |set_read_secret|. This ensures the caller can always ACK any
+  // packet it decrypts. Note this means the server installs 1-RTT write keys
+  // before 0-RTT read keys.
+  //
+  // The converse is not true. An encryption level may be configured with write
+  // secrets a roundtrip before the corresponding secrets for reading ACKs is
+  // available.
+  int (*set_read_secret)(SSL *ssl, enum ssl_encryption_level_t level,
+                         const SSL_CIPHER *cipher, const uint8_t *secret,
+                         size_t secret_len);
+  // set_write_secret behaves like |set_read_secret| but configures the write
+  // secret and cipher suite for the given encryption level. It will be called
+  // at most once per encryption level.
+  //
+  // BoringSSL will not release write keys before QUIC may use them. If |level|
+  // is |ssl_encryption_early_data| or |ssl_encryption_application|, QUIC may
+  // begin sending application data at |level|. However, note that BoringSSL
+  // configures server |ssl_encryption_application| write keys before the client
+  // Finished. This allows QUIC to send half-RTT data, but the handshake is not
+  // confirmed at this point and, if requesting client certificates, the client
+  // is not yet authenticated.
+  //
+  // See |set_read_secret| for additional invariants between packets and their
+  // ACKs.
+  //
+  // Note that, on 0-RTT reject, the |ssl_encryption_early_data| write secret
+  // may use a different cipher suite from the other keys.
+  int (*set_write_secret)(SSL *ssl, enum ssl_encryption_level_t level,
+                          const SSL_CIPHER *cipher, const uint8_t *secret,
+                          size_t secret_len);
+  // add_handshake_data adds handshake data to the current flight at the given
+  // encryption level. It returns one on success and zero on error.
+  //
+  // BoringSSL will pack data from a single encryption level together, but a
+  // single handshake flight may include multiple encryption levels. Callers
+  // should defer writing data to the network until |flush_flight| to better
+  // pack QUIC packets into transport datagrams.
+  //
+  // If |level| is not |ssl_encryption_initial|, this function will not be
+  // called before |level| is initialized with |set_write_secret|.
+  int (*add_handshake_data)(SSL *ssl, enum ssl_encryption_level_t level,
+                            const uint8_t *data, size_t len);
+  // flush_flight is called when the current flight is complete and should be
+  // written to the transport. Note a flight may contain data at several
+  // encryption levels. It returns one on success and zero on error.
+  int (*flush_flight)(SSL *ssl);
+  // send_alert sends a fatal alert at the specified encryption level. It
+  // returns one on success and zero on error.
+  //
+  // If |level| is not |ssl_encryption_initial|, this function will not be
+  // called before |level| is initialized with |set_write_secret|.
+  int (*send_alert)(SSL *ssl, enum ssl_encryption_level_t level, uint8_t alert);
+};
+
+// SSL_quic_max_handshake_flight_len returns returns the maximum number of bytes
+// that may be received at the given encryption level. This function should be
+// used to limit buffering in the QUIC implementation.
+//
+// See https://www.rfc-editor.org/rfc/rfc9000#section-7.5
+OPENSSL_EXPORT size_t SSL_quic_max_handshake_flight_len(
+    const SSL *ssl, enum ssl_encryption_level_t level);
+
+// SSL_quic_read_level returns the current read encryption level.
+//
+// TODO(davidben): Is it still necessary to expose this function to callers?
+// QUICHE does not use it.
+OPENSSL_EXPORT enum ssl_encryption_level_t SSL_quic_read_level(const SSL *ssl);
+
+// SSL_quic_write_level returns the current write encryption level.
+//
+// TODO(davidben): Is it still necessary to expose this function to callers?
+// QUICHE does not use it.
+OPENSSL_EXPORT enum ssl_encryption_level_t SSL_quic_write_level(const SSL *ssl);
+
+// SSL_provide_quic_data provides data from QUIC at a particular encryption
+// level |level|. It returns one on success and zero on error. Note this
+// function will return zero if the handshake is not expecting data from |level|
+// at this time. The QUIC implementation should then close the connection with
+// an error.
+OPENSSL_EXPORT int SSL_provide_quic_data(SSL *ssl,
+                                         enum ssl_encryption_level_t level,
+                                         const uint8_t *data, size_t len);
+
+
+// SSL_process_quic_post_handshake processes any data that QUIC has provided
+// after the handshake has completed. This includes NewSessionTicket messages
+// sent by the server. It returns one on success and zero on error.
+OPENSSL_EXPORT int SSL_process_quic_post_handshake(SSL *ssl);
+
+// SSL_CTX_set_quic_method configures the QUIC hooks. This should only be
+// configured with a minimum version of TLS 1.3. |quic_method| must remain valid
+// for the lifetime of |ctx|. It returns one on success and zero on error.
+OPENSSL_EXPORT int SSL_CTX_set_quic_method(SSL_CTX *ctx,
+                                           const SSL_QUIC_METHOD *quic_method);
+
+// SSL_set_quic_method configures the QUIC hooks. This should only be
+// configured with a minimum version of TLS 1.3. |quic_method| must remain valid
+// for the lifetime of |ssl|. It returns one on success and zero on error.
+OPENSSL_EXPORT int SSL_set_quic_method(SSL *ssl,
+                                       const SSL_QUIC_METHOD *quic_method);
+
+// SSL_set_quic_transport_params configures |ssl| to send |params| (of length
+// |params_len|) in the quic_transport_parameters extension in either the
+// ClientHello or EncryptedExtensions handshake message. It is an error to set
+// transport parameters if |ssl| is not configured for QUIC. The buffer pointed
+// to by |params| only need be valid for the duration of the call to this
+// function. This function returns 1 on success and 0 on failure.
+OPENSSL_EXPORT int SSL_set_quic_transport_params(SSL *ssl,
+                                                 const uint8_t *params,
+                                                 size_t params_len);
+
+// SSL_get_peer_quic_transport_params provides the caller with the value of the
+// quic_transport_parameters extension sent by the peer. A pointer to the buffer
+// containing the TransportParameters will be put in |*out_params|, and its
+// length in |*params_len|. This buffer will be valid for the lifetime of the
+// |SSL|. If no params were received from the peer, |*out_params_len| will be 0.
+OPENSSL_EXPORT void SSL_get_peer_quic_transport_params(
+    const SSL *ssl, const uint8_t **out_params, size_t *out_params_len);
+
+// SSL_set_quic_use_legacy_codepoint configures whether to use the legacy QUIC
+// extension codepoint 0xffa5 as opposed to the official value 57. Call with
+// |use_legacy| set to 1 to use 0xffa5 and call with 0 to use 57. By default,
+// the standard code point is used.
+OPENSSL_EXPORT void SSL_set_quic_use_legacy_codepoint(SSL *ssl, int use_legacy);
+
+// SSL_set_quic_early_data_context configures a context string in QUIC servers
+// for accepting early data. If a resumption connection offers early data, the
+// server will check if the value matches that of the connection which minted
+// the ticket. If not, resumption still succeeds but early data is rejected.
+// This should include all QUIC Transport Parameters except ones specified that
+// the client MUST NOT remember. This should also include any application
+// protocol-specific state. For HTTP/3, this should be the serialized server
+// SETTINGS frame and the QUIC Transport Parameters (except the stateless reset
+// token).
+//
+// This function may be called before |SSL_do_handshake| or during server
+// certificate selection. It returns 1 on success and 0 on failure.
+OPENSSL_EXPORT int SSL_set_quic_early_data_context(SSL *ssl,
+                                                   const uint8_t *context,
+                                                   size_t context_len);
+
+
+// Early data.
+//
+// WARNING: 0-RTT support in BoringSSL is currently experimental and not fully
+// implemented. It may cause interoperability or security failures when used.
+//
+// Early data, or 0-RTT, is a feature in TLS 1.3 which allows clients to send
+// data on the first flight during a resumption handshake. This can save a
+// round-trip in some application protocols.
+//
+// WARNING: A 0-RTT handshake has different security properties from normal
+// handshake, so it is off by default unless opted in. In particular, early data
+// is replayable by a network attacker. Callers must account for this when
+// sending or processing data before the handshake is confirmed. See RFC 8446
+// for more information.
+//
+// As a server, if early data is accepted, |SSL_do_handshake| will complete as
+// soon as the ClientHello is processed and server flight sent. |SSL_write| may
+// be used to send half-RTT data. |SSL_read| will consume early data and
+// transition to 1-RTT data as appropriate. Prior to the transition,
+// |SSL_in_init| will report the handshake is still in progress. Callers may use
+// it or |SSL_in_early_data| to defer or reject requests as needed.
+//
+// Early data as a client is more complex. If the offered session (see
+// |SSL_set_session|) is 0-RTT-capable, the handshake will return after sending
+// the ClientHello. The predicted peer certificates and ALPN protocol will be
+// available via the usual APIs. |SSL_write| will write early data, up to the
+// session's limit. Writes past this limit and |SSL_read| will complete the
+// handshake before continuing. Callers may also call |SSL_do_handshake| again
+// to complete the handshake sooner.
+//
+// If the server accepts early data, the handshake will succeed. |SSL_read| and
+// |SSL_write| will then act as in a 1-RTT handshake. The peer certificates and
+// ALPN protocol will be as predicted and need not be re-queried.
+//
+// If the server rejects early data, |SSL_do_handshake| (and thus |SSL_read| and
+// |SSL_write|) will then fail with |SSL_get_error| returning
+// |SSL_ERROR_EARLY_DATA_REJECTED|. The caller should treat this as a connection
+// error and most likely perform a high-level retry. Note the server may still
+// have processed the early data due to attacker replays.
+//
+// To then continue the handshake on the original connection, use
+// |SSL_reset_early_data_reject|. The connection will then behave as one which
+// had not yet completed the handshake. This allows a faster retry than making a
+// fresh connection. |SSL_do_handshake| will complete the full handshake,
+// possibly resulting in different peer certificates, ALPN protocol, and other
+// properties. The caller must disregard any values from before the reset and
+// query again.
+//
+// Finally, to implement the fallback described in RFC 8446 appendix D.3, retry
+// on a fresh connection without 0-RTT if the handshake fails with
+// |SSL_R_WRONG_VERSION_ON_EARLY_DATA|.
+
+// SSL_CTX_set_early_data_enabled sets whether early data is allowed to be used
+// with resumptions using |ctx|.
+OPENSSL_EXPORT void SSL_CTX_set_early_data_enabled(SSL_CTX *ctx, int enabled);
+
+// SSL_set_early_data_enabled sets whether early data is allowed to be used
+// with resumptions using |ssl|. See |SSL_CTX_set_early_data_enabled| for more
+// information.
+OPENSSL_EXPORT void SSL_set_early_data_enabled(SSL *ssl, int enabled);
+
+// SSL_in_early_data returns one if |ssl| has a pending handshake that has
+// progressed enough to send or receive early data. Clients may call |SSL_write|
+// to send early data, but |SSL_read| will complete the handshake before
+// accepting application data. Servers may call |SSL_read| to read early data
+// and |SSL_write| to send half-RTT data.
+OPENSSL_EXPORT int SSL_in_early_data(const SSL *ssl);
+
+// SSL_SESSION_early_data_capable returns whether early data would have been
+// attempted with |session| if enabled.
+OPENSSL_EXPORT int SSL_SESSION_early_data_capable(const SSL_SESSION *session);
+
+// SSL_SESSION_copy_without_early_data returns a copy of |session| with early
+// data disabled. If |session| already does not support early data, it returns
+// |session| with the reference count increased. The caller takes ownership of
+// the result and must release it with |SSL_SESSION_free|.
+//
+// This function may be used on the client to clear early data support from
+// existing sessions when the server rejects early data. In particular,
+// |SSL_R_WRONG_VERSION_ON_EARLY_DATA| requires a fresh connection to retry, and
+// the client would not want 0-RTT enabled for the next connection attempt.
+OPENSSL_EXPORT SSL_SESSION *SSL_SESSION_copy_without_early_data(
+    SSL_SESSION *session);
+
+// SSL_early_data_accepted returns whether early data was accepted on the
+// handshake performed by |ssl|.
+OPENSSL_EXPORT int SSL_early_data_accepted(const SSL *ssl);
+
+// SSL_reset_early_data_reject resets |ssl| after an early data reject. All
+// 0-RTT state is discarded, including any pending |SSL_write| calls. The caller
+// should treat |ssl| as a logically fresh connection, usually by driving the
+// handshake to completion using |SSL_do_handshake|.
+//
+// It is an error to call this function on an |SSL| object that is not signaling
+// |SSL_ERROR_EARLY_DATA_REJECTED|.
+OPENSSL_EXPORT void SSL_reset_early_data_reject(SSL *ssl);
+
+// SSL_get_ticket_age_skew returns the difference, in seconds, between the
+// client-sent ticket age and the server-computed value in TLS 1.3 server
+// connections which resumed a session.
+OPENSSL_EXPORT int32_t SSL_get_ticket_age_skew(const SSL *ssl);
+
+// An ssl_early_data_reason_t describes why 0-RTT was accepted or rejected.
+// These values are persisted to logs. Entries should not be renumbered and
+// numeric values should never be reused.
+enum ssl_early_data_reason_t BORINGSSL_ENUM_INT {
+  // The handshake has not progressed far enough for the 0-RTT status to be
+  // known.
+  ssl_early_data_unknown = 0,
+  // 0-RTT is disabled for this connection.
+  ssl_early_data_disabled = 1,
+  // 0-RTT was accepted.
+  ssl_early_data_accepted = 2,
+  // The negotiated protocol version does not support 0-RTT.
+  ssl_early_data_protocol_version = 3,
+  // The peer declined to offer or accept 0-RTT for an unknown reason.
+  ssl_early_data_peer_declined = 4,
+  // The client did not offer a session.
+  ssl_early_data_no_session_offered = 5,
+  // The server declined to resume the session.
+  ssl_early_data_session_not_resumed = 6,
+  // The session does not support 0-RTT.
+  ssl_early_data_unsupported_for_session = 7,
+  // The server sent a HelloRetryRequest.
+  ssl_early_data_hello_retry_request = 8,
+  // The negotiated ALPN protocol did not match the session.
+  ssl_early_data_alpn_mismatch = 9,
+  // The connection negotiated Channel ID, which is incompatible with 0-RTT.
+  ssl_early_data_channel_id = 10,
+  // Value 11 is reserved. (It has historically |ssl_early_data_token_binding|.)
+  // The client and server ticket age were too far apart.
+  ssl_early_data_ticket_age_skew = 12,
+  // QUIC parameters differ between this connection and the original.
+  ssl_early_data_quic_parameter_mismatch = 13,
+  // The application settings did not match the session.
+  ssl_early_data_alps_mismatch = 14,
+  // The value of the largest entry.
+  ssl_early_data_reason_max_value = ssl_early_data_alps_mismatch,
+};
+
+// SSL_get_early_data_reason returns details why 0-RTT was accepted or rejected
+// on |ssl|. This is primarily useful on the server.
+OPENSSL_EXPORT enum ssl_early_data_reason_t SSL_get_early_data_reason(
+    const SSL *ssl);
+
+// SSL_early_data_reason_string returns a string representation for |reason|, or
+// NULL if |reason| is unknown. This function may be used for logging.
+OPENSSL_EXPORT const char *SSL_early_data_reason_string(
+    enum ssl_early_data_reason_t reason);
+
+
+// Encrypted ClientHello.
+//
+// ECH is a mechanism for encrypting the entire ClientHello message in TLS 1.3.
+// This can prevent observers from seeing cleartext information about the
+// connection, such as the server_name extension.
+//
+// By default, BoringSSL will treat the server name, session ticket, and client
+// certificate as secret, but most other parameters, such as the ALPN protocol
+// list will be treated as public and sent in the cleartext ClientHello. Other
+// APIs may be added for applications with different secrecy requirements.
+//
+// ECH support in BoringSSL is still experimental and under development.
+//
+// See https://tools.ietf.org/html/draft-ietf-tls-esni-13.
+
+// SSL_set_enable_ech_grease configures whether the client will send a GREASE
+// ECH extension when no supported ECHConfig is available.
+OPENSSL_EXPORT void SSL_set_enable_ech_grease(SSL *ssl, int enable);
+
+// SSL_set1_ech_config_list configures |ssl| to, as a client, offer ECH with the
+// specified configuration. |ech_config_list| should contain a serialized
+// ECHConfigList structure. It returns one on success and zero on error.
+//
+// This function returns an error if the input is malformed. If the input is
+// valid but none of the ECHConfigs implement supported parameters, it will
+// return success and proceed without ECH.
+//
+// If a supported ECHConfig is found, |ssl| will encrypt the true ClientHello
+// parameters. If the server cannot decrypt it, e.g. due to a key mismatch, ECH
+// has a recovery flow. |ssl| will handshake using the cleartext parameters,
+// including a public name in the ECHConfig. If using
+// |SSL_CTX_set_custom_verify|, callers should use |SSL_get0_ech_name_override|
+// to verify the certificate with the public name. If using the built-in
+// verifier, the |X509_STORE_CTX| will be configured automatically.
+//
+// If no other errors are found in this handshake, it will fail with
+// |SSL_R_ECH_REJECTED|. Since it didn't use the true parameters, the connection
+// cannot be used for application data. Instead, callers should handle this
+// error by calling |SSL_get0_ech_retry_configs| and retrying the connection
+// with updated ECH parameters. If the retry also fails with
+// |SSL_R_ECH_REJECTED|, the caller should report a connection failure.
+OPENSSL_EXPORT int SSL_set1_ech_config_list(SSL *ssl,
+                                            const uint8_t *ech_config_list,
+                                            size_t ech_config_list_len);
+
+// SSL_get0_ech_name_override, if |ssl| is a client and the server rejected ECH,
+// sets |*out_name| and |*out_name_len| to point to a buffer containing the ECH
+// public name. Otherwise, the buffer will be empty.
+//
+// When offering ECH as a client, this function should be called during the
+// certificate verification callback (see |SSL_CTX_set_custom_verify|). If
+// |*out_name_len| is non-zero, the caller should verify the certificate against
+// the result, interpreted as a DNS name, rather than the true server name. In
+// this case, the handshake will never succeed and is only used to authenticate
+// retry configs. See also |SSL_get0_ech_retry_configs|.
+OPENSSL_EXPORT void SSL_get0_ech_name_override(const SSL *ssl,
+                                               const char **out_name,
+                                               size_t *out_name_len);
+
+// SSL_get0_ech_retry_configs sets |*out_retry_configs| and
+// |*out_retry_configs_len| to a buffer containing a serialized ECHConfigList.
+// If the server did not provide an ECHConfigList, |*out_retry_configs_len| will
+// be zero.
+//
+// When handling an |SSL_R_ECH_REJECTED| error code as a client, callers should
+// use this function to recover from potential key mismatches. If the result is
+// non-empty, the caller should retry the connection, passing this buffer to
+// |SSL_set1_ech_config_list|. If the result is empty, the server has rolled
+// back ECH support, and the caller should retry without ECH.
+//
+// This function must only be called in response to an |SSL_R_ECH_REJECTED|
+// error code. Calling this function on |ssl|s that have not authenticated the
+// rejection handshake will assert in debug builds and otherwise return an
+// unparsable list.
+OPENSSL_EXPORT void SSL_get0_ech_retry_configs(
+    const SSL *ssl, const uint8_t **out_retry_configs,
+    size_t *out_retry_configs_len);
+
+// SSL_marshal_ech_config constructs a new serialized ECHConfig. On success, it
+// sets |*out| to a newly-allocated buffer containing the result and |*out_len|
+// to the size of the buffer. The caller must call |OPENSSL_free| on |*out| to
+// release the memory. On failure, it returns zero.
+//
+// The |config_id| field is a single byte identifier for the ECHConfig. Reusing
+// config IDs is allowed, but if multiple ECHConfigs with the same config ID are
+// active at a time, server load may increase. See
+// |SSL_ECH_KEYS_has_duplicate_config_id|.
+//
+// The public key and KEM algorithm are taken from |key|. |public_name| is the
+// DNS name used to authenticate the recovery flow. |max_name_len| should be the
+// length of the longest name in the ECHConfig's anonymity set and influences
+// client padding decisions.
+OPENSSL_EXPORT int SSL_marshal_ech_config(uint8_t **out, size_t *out_len,
+                                          uint8_t config_id,
+                                          const EVP_HPKE_KEY *key,
+                                          const char *public_name,
+                                          size_t max_name_len);
+
+// SSL_ECH_KEYS_new returns a newly-allocated |SSL_ECH_KEYS| or NULL on error.
+OPENSSL_EXPORT SSL_ECH_KEYS *SSL_ECH_KEYS_new(void);
+
+// SSL_ECH_KEYS_up_ref increments the reference count of |keys|.
+OPENSSL_EXPORT void SSL_ECH_KEYS_up_ref(SSL_ECH_KEYS *keys);
+
+// SSL_ECH_KEYS_free releases memory associated with |keys|.
+OPENSSL_EXPORT void SSL_ECH_KEYS_free(SSL_ECH_KEYS *keys);
+
+// SSL_ECH_KEYS_add decodes |ech_config| as an ECHConfig and appends it with
+// |key| to |keys|. If |is_retry_config| is non-zero, this config will be
+// returned to the client on configuration mismatch. It returns one on success
+// and zero on error.
+//
+// This function should be called successively to register each ECHConfig in
+// decreasing order of preference. This configuration must be completed before
+// setting |keys| on an |SSL_CTX| with |SSL_CTX_set1_ech_keys|. After that
+// point, |keys| is immutable; no more ECHConfig values may be added.
+//
+// See also |SSL_CTX_set1_ech_keys|.
+OPENSSL_EXPORT int SSL_ECH_KEYS_add(SSL_ECH_KEYS *keys, int is_retry_config,
+                                    const uint8_t *ech_config,
+                                    size_t ech_config_len,
+                                    const EVP_HPKE_KEY *key);
+
+// SSL_ECH_KEYS_has_duplicate_config_id returns one if |keys| has duplicate
+// config IDs or zero otherwise. Duplicate config IDs still work, but may
+// increase server load due to trial decryption.
+OPENSSL_EXPORT int SSL_ECH_KEYS_has_duplicate_config_id(
+    const SSL_ECH_KEYS *keys);
+
+// SSL_ECH_KEYS_marshal_retry_configs serializes the retry configs in |keys| as
+// an ECHConfigList. On success, it sets |*out| to a newly-allocated buffer
+// containing the result and |*out_len| to the size of the buffer. The caller
+// must call |OPENSSL_free| on |*out| to release the memory. On failure, it
+// returns zero.
+//
+// This output may be advertised to clients in DNS.
+OPENSSL_EXPORT int SSL_ECH_KEYS_marshal_retry_configs(const SSL_ECH_KEYS *keys,
+                                                      uint8_t **out,
+                                                      size_t *out_len);
+
+// SSL_CTX_set1_ech_keys configures |ctx| to use |keys| to decrypt encrypted
+// ClientHellos. It returns one on success, and zero on failure. If |keys| does
+// not contain any retry configs, this function will fail. Retry configs are
+// marked as such when they are added to |keys| with |SSL_ECH_KEYS_add|.
+//
+// Once |keys| has been passed to this function, it is immutable. Unlike most
+// |SSL_CTX| configuration functions, this function may be called even if |ctx|
+// already has associated connections on multiple threads. This may be used to
+// rotate keys in a long-lived server process.
+//
+// The configured ECHConfig values should also be advertised out-of-band via DNS
+// (see draft-ietf-dnsop-svcb-https). Before advertising an ECHConfig in DNS,
+// deployments should ensure all instances of the service are configured with
+// the ECHConfig and corresponding private key.
+//
+// Only the most recent fully-deployed ECHConfigs should be advertised in DNS.
+// |keys| may contain a newer set if those ECHConfigs are mid-deployment. It
+// should also contain older sets, until the DNS change has rolled out and the
+// old records have expired from caches.
+//
+// If there is a mismatch, |SSL| objects associated with |ctx| will complete the
+// handshake using the cleartext ClientHello and send updated ECHConfig values
+// to the client. The client will then retry to recover, but with a latency
+// penalty. This recovery flow depends on the public name in the ECHConfig.
+// Before advertising an ECHConfig in DNS, deployments must ensure all instances
+// of the service can present a valid certificate for the public name.
+//
+// BoringSSL negotiates ECH before certificate selection callbacks are called,
+// including |SSL_CTX_set_select_certificate_cb|. If ECH is negotiated, the
+// reported |SSL_CLIENT_HELLO| structure and |SSL_get_servername| function will
+// transparently reflect the inner ClientHello. Callers should select parameters
+// based on these values to correctly handle ECH as well as the recovery flow.
+OPENSSL_EXPORT int SSL_CTX_set1_ech_keys(SSL_CTX *ctx, SSL_ECH_KEYS *keys);
+
+// SSL_ech_accepted returns one if |ssl| negotiated ECH and zero otherwise.
+OPENSSL_EXPORT int SSL_ech_accepted(const SSL *ssl);
+
+
+// Alerts.
+//
+// TLS uses alerts to signal error conditions. Alerts have a type (warning or
+// fatal) and description. OpenSSL internally handles fatal alerts with
+// dedicated error codes (see |SSL_AD_REASON_OFFSET|). Except for close_notify,
+// warning alerts are silently ignored and may only be surfaced with
+// |SSL_CTX_set_info_callback|.
+
+// SSL_AD_REASON_OFFSET is the offset between error reasons and |SSL_AD_*|
+// values. Any error code under |ERR_LIB_SSL| with an error reason above this
+// value corresponds to an alert description. Consumers may add or subtract
+// |SSL_AD_REASON_OFFSET| to convert between them.
+//
+// make_errors.go reserves error codes above 1000 for manually-assigned errors.
+// This value must be kept in sync with reservedReasonCode in make_errors.h
+#define SSL_AD_REASON_OFFSET 1000
+
+// SSL_AD_* are alert descriptions.
+#define SSL_AD_CLOSE_NOTIFY SSL3_AD_CLOSE_NOTIFY
+#define SSL_AD_UNEXPECTED_MESSAGE SSL3_AD_UNEXPECTED_MESSAGE
+#define SSL_AD_BAD_RECORD_MAC SSL3_AD_BAD_RECORD_MAC
+#define SSL_AD_DECRYPTION_FAILED TLS1_AD_DECRYPTION_FAILED
+#define SSL_AD_RECORD_OVERFLOW TLS1_AD_RECORD_OVERFLOW
+#define SSL_AD_DECOMPRESSION_FAILURE SSL3_AD_DECOMPRESSION_FAILURE
+#define SSL_AD_HANDSHAKE_FAILURE SSL3_AD_HANDSHAKE_FAILURE
+#define SSL_AD_NO_CERTIFICATE SSL3_AD_NO_CERTIFICATE  // Legacy SSL 3.0 value
+#define SSL_AD_BAD_CERTIFICATE SSL3_AD_BAD_CERTIFICATE
+#define SSL_AD_UNSUPPORTED_CERTIFICATE SSL3_AD_UNSUPPORTED_CERTIFICATE
+#define SSL_AD_CERTIFICATE_REVOKED SSL3_AD_CERTIFICATE_REVOKED
+#define SSL_AD_CERTIFICATE_EXPIRED SSL3_AD_CERTIFICATE_EXPIRED
+#define SSL_AD_CERTIFICATE_UNKNOWN SSL3_AD_CERTIFICATE_UNKNOWN
+#define SSL_AD_ILLEGAL_PARAMETER SSL3_AD_ILLEGAL_PARAMETER
+#define SSL_AD_UNKNOWN_CA TLS1_AD_UNKNOWN_CA
+#define SSL_AD_ACCESS_DENIED TLS1_AD_ACCESS_DENIED
+#define SSL_AD_DECODE_ERROR TLS1_AD_DECODE_ERROR
+#define SSL_AD_DECRYPT_ERROR TLS1_AD_DECRYPT_ERROR
+#define SSL_AD_EXPORT_RESTRICTION TLS1_AD_EXPORT_RESTRICTION
+#define SSL_AD_PROTOCOL_VERSION TLS1_AD_PROTOCOL_VERSION
+#define SSL_AD_INSUFFICIENT_SECURITY TLS1_AD_INSUFFICIENT_SECURITY
+#define SSL_AD_INTERNAL_ERROR TLS1_AD_INTERNAL_ERROR
+#define SSL_AD_INAPPROPRIATE_FALLBACK SSL3_AD_INAPPROPRIATE_FALLBACK
+#define SSL_AD_USER_CANCELLED TLS1_AD_USER_CANCELLED
+#define SSL_AD_NO_RENEGOTIATION TLS1_AD_NO_RENEGOTIATION
+#define SSL_AD_MISSING_EXTENSION TLS1_AD_MISSING_EXTENSION
+#define SSL_AD_UNSUPPORTED_EXTENSION TLS1_AD_UNSUPPORTED_EXTENSION
+#define SSL_AD_CERTIFICATE_UNOBTAINABLE TLS1_AD_CERTIFICATE_UNOBTAINABLE
+#define SSL_AD_UNRECOGNIZED_NAME TLS1_AD_UNRECOGNIZED_NAME
+#define SSL_AD_BAD_CERTIFICATE_STATUS_RESPONSE \
+  TLS1_AD_BAD_CERTIFICATE_STATUS_RESPONSE
+#define SSL_AD_BAD_CERTIFICATE_HASH_VALUE TLS1_AD_BAD_CERTIFICATE_HASH_VALUE
+#define SSL_AD_UNKNOWN_PSK_IDENTITY TLS1_AD_UNKNOWN_PSK_IDENTITY
+#define SSL_AD_CERTIFICATE_REQUIRED TLS1_AD_CERTIFICATE_REQUIRED
+#define SSL_AD_NO_APPLICATION_PROTOCOL TLS1_AD_NO_APPLICATION_PROTOCOL
+#define SSL_AD_ECH_REQUIRED TLS1_AD_ECH_REQUIRED
+
+// SSL_alert_type_string_long returns a string description of |value| as an
+// alert type (warning or fatal).
+OPENSSL_EXPORT const char *SSL_alert_type_string_long(int value);
+
+// SSL_alert_desc_string_long returns a string description of |value| as an
+// alert description or "unknown" if unknown.
+OPENSSL_EXPORT const char *SSL_alert_desc_string_long(int value);
+
+// SSL_send_fatal_alert sends a fatal alert over |ssl| of the specified type,
+// which should be one of the |SSL_AD_*| constants. It returns one on success
+// and <= 0 on error. The caller should pass the return value into
+// |SSL_get_error| to determine how to proceed. Once this function has been
+// called, future calls to |SSL_write| will fail.
+//
+// If retrying a failed operation due to |SSL_ERROR_WANT_WRITE|, subsequent
+// calls must use the same |alert| parameter.
+OPENSSL_EXPORT int SSL_send_fatal_alert(SSL *ssl, uint8_t alert);
+
+
+// ex_data functions.
+//
+// See |ex_data.h| for details.
+
+OPENSSL_EXPORT int SSL_set_ex_data(SSL *ssl, int idx, void *data);
+OPENSSL_EXPORT void *SSL_get_ex_data(const SSL *ssl, int idx);
+OPENSSL_EXPORT int SSL_get_ex_new_index(long argl, void *argp,
+                                        CRYPTO_EX_unused *unused,
+                                        CRYPTO_EX_dup *dup_unused,
+                                        CRYPTO_EX_free *free_func);
+
+OPENSSL_EXPORT int SSL_SESSION_set_ex_data(SSL_SESSION *session, int idx,
+                                           void *data);
+OPENSSL_EXPORT void *SSL_SESSION_get_ex_data(const SSL_SESSION *session,
+                                             int idx);
+OPENSSL_EXPORT int SSL_SESSION_get_ex_new_index(long argl, void *argp,
+                                                CRYPTO_EX_unused *unused,
+                                                CRYPTO_EX_dup *dup_unused,
+                                                CRYPTO_EX_free *free_func);
+
+OPENSSL_EXPORT int SSL_CTX_set_ex_data(SSL_CTX *ctx, int idx, void *data);
+OPENSSL_EXPORT void *SSL_CTX_get_ex_data(const SSL_CTX *ctx, int idx);
+OPENSSL_EXPORT int SSL_CTX_get_ex_new_index(long argl, void *argp,
+                                            CRYPTO_EX_unused *unused,
+                                            CRYPTO_EX_dup *dup_unused,
+                                            CRYPTO_EX_free *free_func);
+
+OPENSSL_EXPORT int SSL_CREDENTIAL_set_ex_data(SSL_CREDENTIAL *cred, int idx,
+                                              void *data);
+OPENSSL_EXPORT void *SSL_CREDENTIAL_get_ex_data(const SSL_CREDENTIAL *cred,
+                                                int idx);
+OPENSSL_EXPORT int SSL_CREDENTIAL_get_ex_new_index(long argl, void *argp,
+                                                   CRYPTO_EX_unused *unused,
+                                                   CRYPTO_EX_dup *dup_unused,
+                                                   CRYPTO_EX_free *free_func);
+
+
+// Low-level record-layer state.
+
+// SSL_get_ivs sets |*out_iv_len| to the length of the IVs for the ciphers
+// underlying |ssl| and sets |*out_read_iv| and |*out_write_iv| to point to the
+// current IVs for the read and write directions. This is only meaningful for
+// connections with implicit IVs (i.e. CBC mode with TLS 1.0).
+//
+// It returns one on success or zero on error.
+OPENSSL_EXPORT int SSL_get_ivs(const SSL *ssl, const uint8_t **out_read_iv,
+                               const uint8_t **out_write_iv,
+                               size_t *out_iv_len);
+
+// SSL_get_key_block_len returns the length of |ssl|'s key block, for TLS 1.2
+// and below. It is an error to call this function during a handshake, or if
+// |ssl| negotiated TLS 1.3.
+OPENSSL_EXPORT size_t SSL_get_key_block_len(const SSL *ssl);
+
+// SSL_generate_key_block generates |out_len| bytes of key material for |ssl|'s
+// current connection state, for TLS 1.2 and below. It is an error to call this
+// function during a handshake, or if |ssl| negotiated TLS 1.3.
+OPENSSL_EXPORT int SSL_generate_key_block(const SSL *ssl, uint8_t *out,
+                                          size_t out_len);
+
+// SSL_get_read_sequence returns, in TLS, the expected sequence number of the
+// next incoming record in the current epoch. In DTLS, it returns the maximum
+// sequence number received in the current epoch and includes the epoch number
+// in the two most significant bytes.
+OPENSSL_EXPORT uint64_t SSL_get_read_sequence(const SSL *ssl);
+
+// SSL_get_write_sequence returns the sequence number of the next outgoing
+// record in the current epoch. In DTLS, it includes the epoch number in the
+// two most significant bytes.
+OPENSSL_EXPORT uint64_t SSL_get_write_sequence(const SSL *ssl);
+
+// SSL_CTX_set_record_protocol_version returns whether |version| is zero.
+OPENSSL_EXPORT int SSL_CTX_set_record_protocol_version(SSL_CTX *ctx,
+                                                       int version);
+
+
+// Handshake hints.
+//
+// WARNING: Contact the BoringSSL team before using this API. While this
+// mechanism was designed to gracefully recover from version skew and
+// configuration mismatch, splitting a single TLS server into multiple services
+// is complex.
+//
+// Some server deployments make asynchronous RPC calls in both ClientHello
+// dispatch and private key operations. In TLS handshakes where the private key
+// operation occurs in the first round-trip, this results in two consecutive RPC
+// round-trips. Handshake hints allow the RPC service to predict a signature.
+// If correctly predicted, this can skip the second RPC call.
+//
+// First, the server installs a certificate selection callback (see
+// |SSL_CTX_set_select_certificate_cb|). When that is called, it performs the
+// RPC as before, but includes the ClientHello and a capabilities string from
+// |SSL_serialize_capabilities|.
+//
+// Next, the RPC service creates its own |SSL| object, applies the results of
+// certificate selection, calls |SSL_request_handshake_hints|, and runs the
+// handshake. If this successfully computes handshake hints (see
+// |SSL_serialize_handshake_hints|), the RPC server should send the hints
+// alongside any certificate selection results.
+//
+// Finally, the server calls |SSL_set_handshake_hints| and applies any
+// configuration from the RPC server. It then completes the handshake as before.
+// If the hints apply, BoringSSL will use the predicted signature and skip the
+// private key callbacks. Otherwise, BoringSSL will call private key callbacks
+// to generate a signature as before.
+//
+// Callers should synchronize configuration across the two services.
+// Configuration mismatches and some cases of version skew are not fatal, but
+// may result in the hints not applying. Additionally, some handshake flows use
+// the private key in later round-trips, such as TLS 1.3 HelloRetryRequest. In
+// those cases, BoringSSL will not predict a signature as there is no benefit.
+// Callers must allow for handshakes to complete without a predicted signature.
+
+// SSL_serialize_capabilities writes an opaque byte string to |out| describing
+// some of |ssl|'s capabilities. It returns one on success and zero on error.
+//
+// This string is used by BoringSSL internally to reduce the impact of version
+// skew.
+OPENSSL_EXPORT int SSL_serialize_capabilities(const SSL *ssl, CBB *out);
+
+// SSL_request_handshake_hints configures |ssl| to generate a handshake hint for
+// |client_hello|. It returns one on success and zero on error. |client_hello|
+// should contain a serialized ClientHello structure, from the |client_hello|
+// and |client_hello_len| fields of the |SSL_CLIENT_HELLO| structure.
+// |capabilities| should contain the output of |SSL_serialize_capabilities|.
+//
+// When configured, |ssl| will perform no I/O (so there is no need to configure
+// |BIO|s). For QUIC, the caller should still configure an |SSL_QUIC_METHOD|,
+// but the callbacks themselves will never be called and may be left NULL or
+// report failure. |SSL_provide_quic_data| also should not be called.
+//
+// If hint generation is successful, |SSL_do_handshake| will stop the handshake
+// early with |SSL_get_error| returning |SSL_ERROR_HANDSHAKE_HINTS_READY|. At
+// this point, the caller should run |SSL_serialize_handshake_hints| to extract
+// the resulting hints.
+//
+// Hint generation may fail if, e.g., |ssl| was unable to process the
+// ClientHello. Callers should then complete the certificate selection RPC and
+// continue the original handshake with no hint. It will likely fail, but this
+// reports the correct alert to the client and is more robust in case of
+// mismatch.
+OPENSSL_EXPORT int SSL_request_handshake_hints(SSL *ssl,
+                                               const uint8_t *client_hello,
+                                               size_t client_hello_len,
+                                               const uint8_t *capabilities,
+                                               size_t capabilities_len);
+
+// SSL_serialize_handshake_hints writes an opaque byte string to |out|
+// containing the handshake hints computed by |out|. It returns one on success
+// and zero on error. This function should only be called if
+// |SSL_request_handshake_hints| was configured and the handshake terminated
+// with |SSL_ERROR_HANDSHAKE_HINTS_READY|.
+//
+// This string may be passed to |SSL_set_handshake_hints| on another |SSL| to
+// avoid an extra signature call.
+OPENSSL_EXPORT int SSL_serialize_handshake_hints(const SSL *ssl, CBB *out);
+
+// SSL_set_handshake_hints configures |ssl| to use |hints| as handshake hints.
+// It returns one on success and zero on error. The handshake will then continue
+// as before, but apply predicted values from |hints| where applicable.
+//
+// Hints may contain connection and session secrets, so they must not leak and
+// must come from a source trusted to terminate the connection. However, they
+// will not change |ssl|'s configuration. The caller is responsible for
+// serializing and applying options from the RPC server as needed. This ensures
+// |ssl|'s behavior is self-consistent and consistent with the caller's local
+// decisions.
+OPENSSL_EXPORT int SSL_set_handshake_hints(SSL *ssl, const uint8_t *hints,
+                                           size_t hints_len);
+
+
+// Obscure functions.
+
+// SSL_CTX_set_msg_callback installs |cb| as the message callback for |ctx|.
+// This callback will be called when sending or receiving low-level record
+// headers, complete handshake messages, ChangeCipherSpec, and alerts.
+// |write_p| is one for outgoing messages and zero for incoming messages.
+//
+// For each record header, |cb| is called with |version| = 0 and |content_type|
+// = |SSL3_RT_HEADER|. The |len| bytes from |buf| contain the header. Note that
+// this does not include the record body. If the record is sealed, the length
+// in the header is the length of the ciphertext.
+//
+// For each handshake message, ChangeCipherSpec, and alert, |version| is the
+// protocol version and |content_type| is the corresponding record type. The
+// |len| bytes from |buf| contain the handshake message, one-byte
+// ChangeCipherSpec body, and two-byte alert, respectively.
+//
+// In connections that enable ECH, |cb| is additionally called with
+// |content_type| = |SSL3_RT_CLIENT_HELLO_INNER| for each ClientHelloInner that
+// is encrypted or decrypted. The |len| bytes from |buf| contain the
+// ClientHelloInner, including the reconstructed outer extensions and handshake
+// header.
+//
+// For a V2ClientHello, |version| is |SSL2_VERSION|, |content_type| is zero, and
+// the |len| bytes from |buf| contain the V2ClientHello structure.
+OPENSSL_EXPORT void SSL_CTX_set_msg_callback(
+    SSL_CTX *ctx, void (*cb)(int is_write, int version, int content_type,
+                             const void *buf, size_t len, SSL *ssl, void *arg));
+
+// SSL_CTX_set_msg_callback_arg sets the |arg| parameter of the message
+// callback.
+OPENSSL_EXPORT void SSL_CTX_set_msg_callback_arg(SSL_CTX *ctx, void *arg);
+
+// SSL_set_msg_callback installs |cb| as the message callback of |ssl|. See
+// |SSL_CTX_set_msg_callback| for when this callback is called.
+OPENSSL_EXPORT void SSL_set_msg_callback(
+    SSL *ssl, void (*cb)(int write_p, int version, int content_type,
+                         const void *buf, size_t len, SSL *ssl, void *arg));
+
+// SSL_set_msg_callback_arg sets the |arg| parameter of the message callback.
+OPENSSL_EXPORT void SSL_set_msg_callback_arg(SSL *ssl, void *arg);
+
+// SSL_CTX_set_keylog_callback configures a callback to log key material. This
+// is intended for debugging use with tools like Wireshark. The |cb| function
+// should log |line| followed by a newline, synchronizing with any concurrent
+// access to the log.
+//
+// The format is described in
+// https://www.ietf.org/archive/id/draft-ietf-tls-keylogfile-01.html
+//
+// WARNING: The data in |line| allows an attacker to break security properties
+// of the TLS protocol, including confidentiality, integrity, and forward
+// secrecy. This impacts both the current connection, and, in TLS 1.2, future
+// connections that resume a session from it. Both direct access to the data and
+// side channel leaks from application code are possible attack vectors. This
+// callback is intended for debugging and should not be used in production
+// connections.
+OPENSSL_EXPORT void SSL_CTX_set_keylog_callback(SSL_CTX *ctx,
+                                                void (*cb)(const SSL *ssl,
+                                                           const char *line));
+
+// SSL_CTX_get_keylog_callback returns the callback configured by
+// |SSL_CTX_set_keylog_callback|.
+OPENSSL_EXPORT void (*SSL_CTX_get_keylog_callback(const SSL_CTX *ctx))(
+    const SSL *ssl, const char *line);
+
+// SSL_CTX_set_current_time_cb configures a callback to retrieve the current
+// time, which should be set in |*out_clock|. This can be used for testing
+// purposes; for example, a callback can be configured that returns a time
+// set explicitly by the test. The |ssl| pointer passed to |cb| is always null.
+OPENSSL_EXPORT void SSL_CTX_set_current_time_cb(
+    SSL_CTX *ctx, void (*cb)(const SSL *ssl, struct timeval *out_clock));
+
+// SSL_set_shed_handshake_config allows some of the configuration of |ssl| to be
+// freed after its handshake completes.  Once configuration has been shed, APIs
+// that query it may fail.  "Configuration" in this context means anything that
+// was set by the caller, as distinct from information derived from the
+// handshake.  For example, |SSL_get_ciphers| queries how the |SSL| was
+// configured by the caller, and fails after configuration has been shed,
+// whereas |SSL_get_cipher| queries the result of the handshake, and is
+// unaffected by configuration shedding.
+//
+// If configuration shedding is enabled, it is an error to call |SSL_clear|.
+//
+// Note that configuration shedding as a client additionally depends on
+// renegotiation being disabled (see |SSL_set_renegotiate_mode|). If
+// renegotiation is possible, the configuration will be retained. If
+// configuration shedding is enabled and renegotiation later disabled after the
+// handshake, |SSL_set_renegotiate_mode| will shed configuration then. This may
+// be useful for clients which support renegotiation with some ALPN protocols,
+// such as HTTP/1.1, and not others, such as HTTP/2.
+OPENSSL_EXPORT void SSL_set_shed_handshake_config(SSL *ssl, int enable);
+
+enum ssl_renegotiate_mode_t BORINGSSL_ENUM_INT {
+  ssl_renegotiate_never = 0,
+  ssl_renegotiate_once,
+  ssl_renegotiate_freely,
+  ssl_renegotiate_ignore,
+  ssl_renegotiate_explicit,
+};
+
+// SSL_set_renegotiate_mode configures how |ssl|, a client, reacts to
+// renegotiation attempts by a server. If |ssl| is a server, peer-initiated
+// renegotiations are *always* rejected and this function does nothing.
+//
+// WARNING: Renegotiation is error-prone, complicates TLS's security properties,
+// and increases its attack surface. When enabled, many common assumptions about
+// BoringSSL's behavior no longer hold, and the calling application must handle
+// more cases. Renegotiation is also incompatible with many application
+// protocols, e.g. section 9.2.1 of RFC 7540. Many functions behave in ambiguous
+// or undefined ways during a renegotiation.
+//
+// The renegotiation mode defaults to |ssl_renegotiate_never|, but may be set
+// at any point in a connection's lifetime. Set it to |ssl_renegotiate_once| to
+// allow one renegotiation, |ssl_renegotiate_freely| to allow all
+// renegotiations or |ssl_renegotiate_ignore| to ignore HelloRequest messages.
+// Note that ignoring HelloRequest messages may cause the connection to stall
+// if the server waits for the renegotiation to complete.
+//
+// If set to |ssl_renegotiate_explicit|, |SSL_read| and |SSL_peek| calls which
+// encounter a HelloRequest will pause with |SSL_ERROR_WANT_RENEGOTIATE|.
+// |SSL_write| will continue to work while paused. The caller may call
+// |SSL_renegotiate| to begin the renegotiation at a later point. This mode may
+// be used if callers wish to eagerly call |SSL_peek| without triggering a
+// renegotiation.
+//
+// If configuration shedding is enabled (see |SSL_set_shed_handshake_config|),
+// configuration is released if, at any point after the handshake, renegotiation
+// is disabled. It is not possible to switch from disabling renegotiation to
+// enabling it on a given connection. Callers that condition renegotiation on,
+// e.g., ALPN must enable renegotiation before the handshake and conditionally
+// disable it afterwards.
+//
+// When enabled, renegotiation can cause properties of |ssl|, such as the cipher
+// suite, to change during the lifetime of the connection. More over, during a
+// renegotiation, not all properties of the new handshake are available or fully
+// established. In BoringSSL, most functions, such as |SSL_get_current_cipher|,
+// report information from the most recently completed handshake, not the
+// pending one. However, renegotiation may rerun handshake callbacks, such as
+// |SSL_CTX_set_cert_cb|. Such callbacks must ensure they are acting on the
+// desired versions of each property.
+//
+// BoringSSL does not reverify peer certificates on renegotiation and instead
+// requires they match between handshakes, so certificate verification callbacks
+// (see |SSL_CTX_set_custom_verify|) may assume |ssl| is in the initial
+// handshake and use |SSL_get0_peer_certificates|, etc.
+//
+// There is no support in BoringSSL for initiating renegotiations as a client
+// or server.
+OPENSSL_EXPORT void SSL_set_renegotiate_mode(SSL *ssl,
+                                             enum ssl_renegotiate_mode_t mode);
+
+// SSL_renegotiate starts a deferred renegotiation on |ssl| if it was configured
+// with |ssl_renegotiate_explicit| and has a pending HelloRequest. It returns
+// one on success and zero on error.
+//
+// This function does not do perform any I/O. On success, a subsequent
+// |SSL_do_handshake| call will run the handshake. |SSL_write| and
+// |SSL_read| will also complete the handshake before sending or receiving
+// application data.
+OPENSSL_EXPORT int SSL_renegotiate(SSL *ssl);
+
+// SSL_renegotiate_pending returns one if |ssl| is in the middle of a
+// renegotiation.
+OPENSSL_EXPORT int SSL_renegotiate_pending(SSL *ssl);
+
+// SSL_total_renegotiations returns the total number of renegotiation handshakes
+// performed by |ssl|. This includes the pending renegotiation, if any.
+OPENSSL_EXPORT int SSL_total_renegotiations(const SSL *ssl);
+
+// SSL_MAX_CERT_LIST_DEFAULT is the default maximum length, in bytes, of a peer
+// certificate chain.
+#define SSL_MAX_CERT_LIST_DEFAULT (1024 * 100)
+
+// SSL_CTX_get_max_cert_list returns the maximum length, in bytes, of a peer
+// certificate chain accepted by |ctx|.
+OPENSSL_EXPORT size_t SSL_CTX_get_max_cert_list(const SSL_CTX *ctx);
+
+// SSL_CTX_set_max_cert_list sets the maximum length, in bytes, of a peer
+// certificate chain to |max_cert_list|. This affects how much memory may be
+// consumed during the handshake.
+OPENSSL_EXPORT void SSL_CTX_set_max_cert_list(SSL_CTX *ctx,
+                                              size_t max_cert_list);
+
+// SSL_get_max_cert_list returns the maximum length, in bytes, of a peer
+// certificate chain accepted by |ssl|.
+OPENSSL_EXPORT size_t SSL_get_max_cert_list(const SSL *ssl);
+
+// SSL_set_max_cert_list sets the maximum length, in bytes, of a peer
+// certificate chain to |max_cert_list|. This affects how much memory may be
+// consumed during the handshake.
+OPENSSL_EXPORT void SSL_set_max_cert_list(SSL *ssl, size_t max_cert_list);
+
+// SSL_CTX_set_max_send_fragment sets the maximum length, in bytes, of records
+// sent by |ctx|. Beyond this length, handshake messages and application data
+// will be split into multiple records. It returns one on success or zero on
+// error.
+OPENSSL_EXPORT int SSL_CTX_set_max_send_fragment(SSL_CTX *ctx,
+                                                 size_t max_send_fragment);
+
+// SSL_set_max_send_fragment sets the maximum length, in bytes, of records sent
+// by |ssl|. Beyond this length, handshake messages and application data will
+// be split into multiple records. It returns one on success or zero on
+// error.
+OPENSSL_EXPORT int SSL_set_max_send_fragment(SSL *ssl,
+                                             size_t max_send_fragment);
+
+// ssl_early_callback_ctx (aka |SSL_CLIENT_HELLO|) is passed to certain
+// callbacks that are called very early on during the server handshake. At this
+// point, much of the SSL* hasn't been filled out and only the ClientHello can
+// be depended on.
+struct ssl_early_callback_ctx {
+  SSL *ssl;
+  const uint8_t *client_hello;
+  size_t client_hello_len;
+  uint16_t version;
+  const uint8_t *random;
+  size_t random_len;
+  const uint8_t *session_id;
+  size_t session_id_len;
+  const uint8_t *cipher_suites;
+  size_t cipher_suites_len;
+  const uint8_t *compression_methods;
+  size_t compression_methods_len;
+  const uint8_t *extensions;
+  size_t extensions_len;
+} /* SSL_CLIENT_HELLO */;
+
+// ssl_select_cert_result_t enumerates the possible results from selecting a
+// certificate with |select_certificate_cb|.
+enum ssl_select_cert_result_t BORINGSSL_ENUM_INT {
+  // ssl_select_cert_success indicates that the certificate selection was
+  // successful.
+  ssl_select_cert_success = 1,
+  // ssl_select_cert_retry indicates that the operation could not be
+  // immediately completed and must be reattempted at a later point.
+  ssl_select_cert_retry = 0,
+  // ssl_select_cert_error indicates that a fatal error occured and the
+  // handshake should be terminated.
+  ssl_select_cert_error = -1,
+};
+
+// SSL_early_callback_ctx_extension_get searches the extensions in
+// |client_hello| for an extension of the given type. If not found, it returns
+// zero. Otherwise it sets |out_data| to point to the extension contents (not
+// including the type and length bytes), sets |out_len| to the length of the
+// extension contents and returns one.
+OPENSSL_EXPORT int SSL_early_callback_ctx_extension_get(
+    const SSL_CLIENT_HELLO *client_hello, uint16_t extension_type,
+    const uint8_t **out_data, size_t *out_len);
+
+// SSL_CTX_set_select_certificate_cb sets a callback that is called before most
+// ClientHello processing and before the decision whether to resume a session
+// is made. The callback may inspect the ClientHello and configure the
+// connection. See |ssl_select_cert_result_t| for details of the return values.
+//
+// In the case that a retry is indicated, |SSL_get_error| will return
+// |SSL_ERROR_PENDING_CERTIFICATE| and the caller should arrange for the
+// high-level operation on |ssl| to be retried at a later time, which will
+// result in another call to |cb|.
+//
+// |SSL_get_servername| may be used during this callback.
+//
+// Note: The |SSL_CLIENT_HELLO| is only valid for the duration of the callback
+// and is not valid while the handshake is paused.
+OPENSSL_EXPORT void SSL_CTX_set_select_certificate_cb(
+    SSL_CTX *ctx,
+    enum ssl_select_cert_result_t (*cb)(const SSL_CLIENT_HELLO *));
+
+// SSL_CTX_set_dos_protection_cb sets a callback that is called once the
+// resumption decision for a ClientHello has been made. It can return one to
+// allow the handshake to continue or zero to cause the handshake to abort.
+OPENSSL_EXPORT void SSL_CTX_set_dos_protection_cb(
+    SSL_CTX *ctx, int (*cb)(const SSL_CLIENT_HELLO *));
+
+// SSL_CTX_set_reverify_on_resume configures whether the certificate
+// verification callback will be used to reverify stored certificates
+// when resuming a session. This only works with |SSL_CTX_set_custom_verify|.
+// For now, this is incompatible with |SSL_VERIFY_NONE| mode, and is only
+// respected on clients.
+OPENSSL_EXPORT void SSL_CTX_set_reverify_on_resume(SSL_CTX *ctx, int enabled);
+
+// SSL_set_enforce_rsa_key_usage configures whether, when |ssl| is a client
+// negotiating TLS 1.2 or below, the keyUsage extension of RSA leaf server
+// certificates will be checked for consistency with the TLS usage. In all other
+// cases, this check is always enabled.
+//
+// This parameter may be set late; it will not be read until after the
+// certificate verification callback.
+OPENSSL_EXPORT void SSL_set_enforce_rsa_key_usage(SSL *ssl, int enabled);
+
+// SSL_was_key_usage_invalid returns one if |ssl|'s handshake succeeded despite
+// using TLS parameters which were incompatible with the leaf certificate's
+// keyUsage extension. Otherwise, it returns zero.
+//
+// If |SSL_set_enforce_rsa_key_usage| is enabled or not applicable, this
+// function will always return zero because key usages will be consistently
+// checked.
+OPENSSL_EXPORT int SSL_was_key_usage_invalid(const SSL *ssl);
+
+// SSL_ST_* are possible values for |SSL_state|, the bitmasks that make them up,
+// and some historical values for compatibility. Only |SSL_ST_INIT| and
+// |SSL_ST_OK| are ever returned.
+#define SSL_ST_CONNECT 0x1000
+#define SSL_ST_ACCEPT 0x2000
+#define SSL_ST_MASK 0x0FFF
+#define SSL_ST_INIT (SSL_ST_CONNECT | SSL_ST_ACCEPT)
+#define SSL_ST_OK 0x03
+#define SSL_ST_RENEGOTIATE (0x04 | SSL_ST_INIT)
+#define SSL_ST_BEFORE (0x05 | SSL_ST_INIT)
+
+// TLS_ST_* are aliases for |SSL_ST_*| for OpenSSL 1.1.0 compatibility.
+#define TLS_ST_OK SSL_ST_OK
+#define TLS_ST_BEFORE SSL_ST_BEFORE
+
+// SSL_CB_* are possible values for the |type| parameter in the info
+// callback and the bitmasks that make them up.
+#define SSL_CB_LOOP 0x01
+#define SSL_CB_EXIT 0x02
+#define SSL_CB_READ 0x04
+#define SSL_CB_WRITE 0x08
+#define SSL_CB_ALERT 0x4000
+#define SSL_CB_READ_ALERT (SSL_CB_ALERT | SSL_CB_READ)
+#define SSL_CB_WRITE_ALERT (SSL_CB_ALERT | SSL_CB_WRITE)
+#define SSL_CB_ACCEPT_LOOP (SSL_ST_ACCEPT | SSL_CB_LOOP)
+#define SSL_CB_ACCEPT_EXIT (SSL_ST_ACCEPT | SSL_CB_EXIT)
+#define SSL_CB_CONNECT_LOOP (SSL_ST_CONNECT | SSL_CB_LOOP)
+#define SSL_CB_CONNECT_EXIT (SSL_ST_CONNECT | SSL_CB_EXIT)
+#define SSL_CB_HANDSHAKE_START 0x10
+#define SSL_CB_HANDSHAKE_DONE 0x20
+
+// SSL_CTX_set_info_callback configures a callback to be run when various
+// events occur during a connection's lifetime. The |type| argument determines
+// the type of event and the meaning of the |value| argument. Callbacks must
+// ignore unexpected |type| values.
+//
+// |SSL_CB_READ_ALERT| is signaled for each alert received, warning or fatal.
+// The |value| argument is a 16-bit value where the alert level (either
+// |SSL3_AL_WARNING| or |SSL3_AL_FATAL|) is in the most-significant eight bits
+// and the alert type (one of |SSL_AD_*|) is in the least-significant eight.
+//
+// |SSL_CB_WRITE_ALERT| is signaled for each alert sent. The |value| argument
+// is constructed as with |SSL_CB_READ_ALERT|.
+//
+// |SSL_CB_HANDSHAKE_START| is signaled when a handshake begins. The |value|
+// argument is always one.
+//
+// |SSL_CB_HANDSHAKE_DONE| is signaled when a handshake completes successfully.
+// The |value| argument is always one. If a handshake False Starts, this event
+// may be used to determine when the Finished message is received.
+//
+// The following event types expose implementation details of the handshake
+// state machine. Consuming them is deprecated.
+//
+// |SSL_CB_ACCEPT_LOOP| (respectively, |SSL_CB_CONNECT_LOOP|) is signaled when
+// a server (respectively, client) handshake progresses. The |value| argument
+// is always one.
+//
+// |SSL_CB_ACCEPT_EXIT| (respectively, |SSL_CB_CONNECT_EXIT|) is signaled when
+// a server (respectively, client) handshake completes, fails, or is paused.
+// The |value| argument is one if the handshake succeeded and <= 0
+// otherwise.
+OPENSSL_EXPORT void SSL_CTX_set_info_callback(
+    SSL_CTX *ctx, void (*cb)(const SSL *ssl, int type, int value));
+
+// SSL_CTX_get_info_callback returns the callback set by
+// |SSL_CTX_set_info_callback|.
+OPENSSL_EXPORT void (*SSL_CTX_get_info_callback(SSL_CTX *ctx))(const SSL *ssl,
+                                                               int type,
+                                                               int value);
+
+// SSL_set_info_callback configures a callback to be run at various events
+// during a connection's lifetime. See |SSL_CTX_set_info_callback|.
+OPENSSL_EXPORT void SSL_set_info_callback(
+    SSL *ssl, void (*cb)(const SSL *ssl, int type, int value));
+
+// SSL_get_info_callback returns the callback set by |SSL_set_info_callback|.
+OPENSSL_EXPORT void (*SSL_get_info_callback(const SSL *ssl))(const SSL *ssl,
+                                                             int type,
+                                                             int value);
+
+// SSL_state_string_long returns the current state of the handshake state
+// machine as a string. This may be useful for debugging and logging.
+OPENSSL_EXPORT const char *SSL_state_string_long(const SSL *ssl);
+
+#define SSL_SENT_SHUTDOWN 1
+#define SSL_RECEIVED_SHUTDOWN 2
+
+// SSL_get_shutdown returns a bitmask with a subset of |SSL_SENT_SHUTDOWN| and
+// |SSL_RECEIVED_SHUTDOWN| to query whether close_notify was sent or received,
+// respectively.
+OPENSSL_EXPORT int SSL_get_shutdown(const SSL *ssl);
+
+// SSL_get_peer_signature_algorithm returns the signature algorithm used by the
+// peer. If not applicable, it returns zero.
+OPENSSL_EXPORT uint16_t SSL_get_peer_signature_algorithm(const SSL *ssl);
+
+// SSL_get_client_random writes up to |max_out| bytes of the most recent
+// handshake's client_random to |out| and returns the number of bytes written.
+// If |max_out| is zero, it returns the size of the client_random.
+OPENSSL_EXPORT size_t SSL_get_client_random(const SSL *ssl, uint8_t *out,
+                                            size_t max_out);
+
+// SSL_get_server_random writes up to |max_out| bytes of the most recent
+// handshake's server_random to |out| and returns the number of bytes written.
+// If |max_out| is zero, it returns the size of the server_random.
+OPENSSL_EXPORT size_t SSL_get_server_random(const SSL *ssl, uint8_t *out,
+                                            size_t max_out);
+
+// SSL_get_pending_cipher returns the cipher suite for the current handshake or
+// NULL if one has not been negotiated yet or there is no pending handshake.
+OPENSSL_EXPORT const SSL_CIPHER *SSL_get_pending_cipher(const SSL *ssl);
+
+// SSL_set_retain_only_sha256_of_client_certs, on a server, sets whether only
+// the SHA-256 hash of peer's certificate should be saved in memory and in the
+// session. This can save memory, ticket size and session cache space. If
+// enabled, |SSL_get_peer_certificate| will return NULL after the handshake
+// completes. See |SSL_SESSION_has_peer_sha256| and
+// |SSL_SESSION_get0_peer_sha256| to query the hash.
+OPENSSL_EXPORT void SSL_set_retain_only_sha256_of_client_certs(SSL *ssl,
+                                                               int enable);
+
+// SSL_CTX_set_retain_only_sha256_of_client_certs, on a server, sets whether
+// only the SHA-256 hash of peer's certificate should be saved in memory and in
+// the session. This can save memory, ticket size and session cache space. If
+// enabled, |SSL_get_peer_certificate| will return NULL after the handshake
+// completes. See |SSL_SESSION_has_peer_sha256| and
+// |SSL_SESSION_get0_peer_sha256| to query the hash.
+OPENSSL_EXPORT void SSL_CTX_set_retain_only_sha256_of_client_certs(SSL_CTX *ctx,
+                                                                   int enable);
+
+// SSL_CTX_set_grease_enabled configures whether sockets on |ctx| should enable
+// GREASE. See RFC 8701.
+OPENSSL_EXPORT void SSL_CTX_set_grease_enabled(SSL_CTX *ctx, int enabled);
+
+// SSL_CTX_set_permute_extensions configures whether sockets on |ctx| should
+// permute extensions. For now, this is only implemented for the ClientHello.
+OPENSSL_EXPORT void SSL_CTX_set_permute_extensions(SSL_CTX *ctx, int enabled);
+
+// SSL_set_permute_extensions configures whether sockets on |ssl| should
+// permute extensions. For now, this is only implemented for the ClientHello.
+OPENSSL_EXPORT void SSL_set_permute_extensions(SSL *ssl, int enabled);
+
+// SSL_max_seal_overhead returns the maximum overhead, in bytes, of sealing a
+// record with |ssl|.
+OPENSSL_EXPORT size_t SSL_max_seal_overhead(const SSL *ssl);
+
+// SSL_CTX_set_false_start_allowed_without_alpn configures whether connections
+// on |ctx| may use False Start (if |SSL_MODE_ENABLE_FALSE_START| is enabled)
+// without negotiating ALPN.
+OPENSSL_EXPORT void SSL_CTX_set_false_start_allowed_without_alpn(SSL_CTX *ctx,
+                                                                 int allowed);
+
+// SSL_used_hello_retry_request returns one if the TLS 1.3 HelloRetryRequest
+// message has been either sent by the server or received by the client. It
+// returns zero otherwise.
+OPENSSL_EXPORT int SSL_used_hello_retry_request(const SSL *ssl);
+
+// SSL_set_jdk11_workaround configures whether to workaround various bugs in
+// JDK 11's TLS 1.3 implementation by disabling TLS 1.3 for such clients.
+//
+// https://bugs.openjdk.java.net/browse/JDK-8211806
+// https://bugs.openjdk.java.net/browse/JDK-8212885
+// https://bugs.openjdk.java.net/browse/JDK-8213202
+OPENSSL_EXPORT void SSL_set_jdk11_workaround(SSL *ssl, int enable);
+
+// SSL_set_check_client_certificate_type configures whether the client, in
+// TLS 1.2 and below, will check its certificate against the server's requested
+// certificate types.
+//
+// By default, this option is enabled. If disabled, certificate selection within
+// the library may not function correctly. This flag is provided temporarily in
+// case of compatibility issues. It will be removed sometime after June 2024.
+OPENSSL_EXPORT void SSL_set_check_client_certificate_type(SSL *ssl, int enable);
+
+// SSL_set_check_ecdsa_curve configures whether the server, in TLS 1.2 and
+// below, will check its certificate against the client's supported ECDSA
+// curves.
+//
+// By default, this option is enabled. If disabled, certificate selection within
+// the library may not function correctly. This flag is provided temporarily in
+// case of compatibility issues. It will be removed sometime after June 2024.
+OPENSSL_EXPORT void SSL_set_check_ecdsa_curve(SSL *ssl, int enable);
+
+
+// Deprecated functions.
+
+// SSL_library_init calls |CRYPTO_library_init| and returns one.
+OPENSSL_EXPORT int SSL_library_init(void);
+
+// SSL_CIPHER_description writes a description of |cipher| into |buf| and
+// returns |buf|. If |buf| is NULL, it returns a newly allocated string, to be
+// freed with |OPENSSL_free|, or NULL on error.
+//
+// The description includes a trailing newline and has the form:
+// AES128-SHA              Kx=RSA      Au=RSA  Enc=AES(128)  Mac=SHA1
+//
+// Consider |SSL_CIPHER_standard_name| or |SSL_CIPHER_get_name| instead.
+OPENSSL_EXPORT const char *SSL_CIPHER_description(const SSL_CIPHER *cipher,
+                                                  char *buf, int len);
+
+// SSL_CIPHER_get_version returns the string "TLSv1/SSLv3".
+OPENSSL_EXPORT const char *SSL_CIPHER_get_version(const SSL_CIPHER *cipher);
+
+typedef void COMP_METHOD;
+typedef struct ssl_comp_st SSL_COMP;
+
+// SSL_COMP_get_compression_methods returns NULL.
+OPENSSL_EXPORT STACK_OF(SSL_COMP) *SSL_COMP_get_compression_methods(void);
+
+// SSL_COMP_add_compression_method returns one.
+OPENSSL_EXPORT int SSL_COMP_add_compression_method(int id, COMP_METHOD *cm);
+
+// SSL_COMP_get_name returns NULL.
+OPENSSL_EXPORT const char *SSL_COMP_get_name(const COMP_METHOD *comp);
+
+// SSL_COMP_get0_name returns the |name| member of |comp|.
+OPENSSL_EXPORT const char *SSL_COMP_get0_name(const SSL_COMP *comp);
+
+// SSL_COMP_get_id returns the |id| member of |comp|.
+OPENSSL_EXPORT int SSL_COMP_get_id(const SSL_COMP *comp);
+
+// SSL_COMP_free_compression_methods does nothing.
+OPENSSL_EXPORT void SSL_COMP_free_compression_methods(void);
+
+// SSLv23_method calls |TLS_method|.
+OPENSSL_EXPORT const SSL_METHOD *SSLv23_method(void);
+
+// These version-specific methods behave exactly like |TLS_method| and
+// |DTLS_method| except they also call |SSL_CTX_set_min_proto_version| and
+// |SSL_CTX_set_max_proto_version| to lock connections to that protocol
+// version.
+OPENSSL_EXPORT const SSL_METHOD *TLSv1_method(void);
+OPENSSL_EXPORT const SSL_METHOD *TLSv1_1_method(void);
+OPENSSL_EXPORT const SSL_METHOD *TLSv1_2_method(void);
+OPENSSL_EXPORT const SSL_METHOD *DTLSv1_method(void);
+OPENSSL_EXPORT const SSL_METHOD *DTLSv1_2_method(void);
+
+// These client- and server-specific methods call their corresponding generic
+// methods.
+OPENSSL_EXPORT const SSL_METHOD *TLS_server_method(void);
+OPENSSL_EXPORT const SSL_METHOD *TLS_client_method(void);
+OPENSSL_EXPORT const SSL_METHOD *SSLv23_server_method(void);
+OPENSSL_EXPORT const SSL_METHOD *SSLv23_client_method(void);
+OPENSSL_EXPORT const SSL_METHOD *TLSv1_server_method(void);
+OPENSSL_EXPORT const SSL_METHOD *TLSv1_client_method(void);
+OPENSSL_EXPORT const SSL_METHOD *TLSv1_1_server_method(void);
+OPENSSL_EXPORT const SSL_METHOD *TLSv1_1_client_method(void);
+OPENSSL_EXPORT const SSL_METHOD *TLSv1_2_server_method(void);
+OPENSSL_EXPORT const SSL_METHOD *TLSv1_2_client_method(void);
+OPENSSL_EXPORT const SSL_METHOD *DTLS_server_method(void);
+OPENSSL_EXPORT const SSL_METHOD *DTLS_client_method(void);
+OPENSSL_EXPORT const SSL_METHOD *DTLSv1_server_method(void);
+OPENSSL_EXPORT const SSL_METHOD *DTLSv1_client_method(void);
+OPENSSL_EXPORT const SSL_METHOD *DTLSv1_2_server_method(void);
+OPENSSL_EXPORT const SSL_METHOD *DTLSv1_2_client_method(void);
+
+// SSL_clear resets |ssl| to allow another connection and returns one on success
+// or zero on failure. It returns most configuration state but releases memory
+// associated with the current connection.
+//
+// Free |ssl| and create a new one instead.
+OPENSSL_EXPORT int SSL_clear(SSL *ssl);
+
+// SSL_CTX_set_tmp_rsa_callback does nothing.
+OPENSSL_EXPORT void SSL_CTX_set_tmp_rsa_callback(
+    SSL_CTX *ctx, RSA *(*cb)(SSL *ssl, int is_export, int keylength));
+
+// SSL_set_tmp_rsa_callback does nothing.
+OPENSSL_EXPORT void SSL_set_tmp_rsa_callback(SSL *ssl,
+                                             RSA *(*cb)(SSL *ssl, int is_export,
+                                                        int keylength));
+
+// SSL_CTX_sess_connect returns zero.
+OPENSSL_EXPORT int SSL_CTX_sess_connect(const SSL_CTX *ctx);
+
+// SSL_CTX_sess_connect_good returns zero.
+OPENSSL_EXPORT int SSL_CTX_sess_connect_good(const SSL_CTX *ctx);
+
+// SSL_CTX_sess_connect_renegotiate returns zero.
+OPENSSL_EXPORT int SSL_CTX_sess_connect_renegotiate(const SSL_CTX *ctx);
+
+// SSL_CTX_sess_accept returns zero.
+OPENSSL_EXPORT int SSL_CTX_sess_accept(const SSL_CTX *ctx);
+
+// SSL_CTX_sess_accept_renegotiate returns zero.
+OPENSSL_EXPORT int SSL_CTX_sess_accept_renegotiate(const SSL_CTX *ctx);
+
+// SSL_CTX_sess_accept_good returns zero.
+OPENSSL_EXPORT int SSL_CTX_sess_accept_good(const SSL_CTX *ctx);
+
+// SSL_CTX_sess_hits returns zero.
+OPENSSL_EXPORT int SSL_CTX_sess_hits(const SSL_CTX *ctx);
+
+// SSL_CTX_sess_cb_hits returns zero.
+OPENSSL_EXPORT int SSL_CTX_sess_cb_hits(const SSL_CTX *ctx);
+
+// SSL_CTX_sess_misses returns zero.
+OPENSSL_EXPORT int SSL_CTX_sess_misses(const SSL_CTX *ctx);
+
+// SSL_CTX_sess_timeouts returns zero.
+OPENSSL_EXPORT int SSL_CTX_sess_timeouts(const SSL_CTX *ctx);
+
+// SSL_CTX_sess_cache_full returns zero.
+OPENSSL_EXPORT int SSL_CTX_sess_cache_full(const SSL_CTX *ctx);
+
+// SSL_cutthrough_complete calls |SSL_in_false_start|.
+OPENSSL_EXPORT int SSL_cutthrough_complete(const SSL *ssl);
+
+// SSL_num_renegotiations calls |SSL_total_renegotiations|.
+OPENSSL_EXPORT int SSL_num_renegotiations(const SSL *ssl);
+
+// SSL_CTX_need_tmp_RSA returns zero.
+OPENSSL_EXPORT int SSL_CTX_need_tmp_RSA(const SSL_CTX *ctx);
+
+// SSL_need_tmp_RSA returns zero.
+OPENSSL_EXPORT int SSL_need_tmp_RSA(const SSL *ssl);
+
+// SSL_CTX_set_tmp_rsa returns one.
+OPENSSL_EXPORT int SSL_CTX_set_tmp_rsa(SSL_CTX *ctx, const RSA *rsa);
+
+// SSL_set_tmp_rsa returns one.
+OPENSSL_EXPORT int SSL_set_tmp_rsa(SSL *ssl, const RSA *rsa);
+
+// SSL_CTX_get_read_ahead returns zero.
+OPENSSL_EXPORT int SSL_CTX_get_read_ahead(const SSL_CTX *ctx);
+
+// SSL_CTX_set_read_ahead returns one.
+OPENSSL_EXPORT int SSL_CTX_set_read_ahead(SSL_CTX *ctx, int yes);
+
+// SSL_get_read_ahead returns zero.
+OPENSSL_EXPORT int SSL_get_read_ahead(const SSL *ssl);
+
+// SSL_set_read_ahead returns one.
+OPENSSL_EXPORT int SSL_set_read_ahead(SSL *ssl, int yes);
+
+// SSL_set_state does nothing.
+OPENSSL_EXPORT void SSL_set_state(SSL *ssl, int state);
+
+// SSL_get_shared_ciphers writes an empty string to |buf| and returns a
+// pointer to |buf|, or NULL if |len| is less than or equal to zero.
+OPENSSL_EXPORT char *SSL_get_shared_ciphers(const SSL *ssl, char *buf, int len);
+
+// SSL_get_shared_sigalgs returns zero.
+OPENSSL_EXPORT int SSL_get_shared_sigalgs(SSL *ssl, int idx, int *psign,
+                                          int *phash, int *psignandhash,
+                                          uint8_t *rsig, uint8_t *rhash);
+
+// SSL_MODE_HANDSHAKE_CUTTHROUGH is the same as SSL_MODE_ENABLE_FALSE_START.
+#define SSL_MODE_HANDSHAKE_CUTTHROUGH SSL_MODE_ENABLE_FALSE_START
+
+// i2d_SSL_SESSION serializes |in|, as described in |i2d_SAMPLE|.
+//
+// Use |SSL_SESSION_to_bytes| instead.
+OPENSSL_EXPORT int i2d_SSL_SESSION(SSL_SESSION *in, uint8_t **pp);
+
+// d2i_SSL_SESSION parses a serialized session from the |length| bytes pointed
+// to by |*pp|, as described in |d2i_SAMPLE|.
+//
+// Use |SSL_SESSION_from_bytes| instead.
+OPENSSL_EXPORT SSL_SESSION *d2i_SSL_SESSION(SSL_SESSION **a, const uint8_t **pp,
+                                            long length);
+
+// i2d_SSL_SESSION_bio serializes |session| and writes the result to |bio|. It
+// returns the number of bytes written on success and <= 0 on error.
+OPENSSL_EXPORT int i2d_SSL_SESSION_bio(BIO *bio, const SSL_SESSION *session);
+
+// d2i_SSL_SESSION_bio reads a serialized |SSL_SESSION| from |bio| and returns a
+// newly-allocated |SSL_SESSION| or NULL on error. If |out| is not NULL, it also
+// frees |*out| and sets |*out| to the new |SSL_SESSION|.
+OPENSSL_EXPORT SSL_SESSION *d2i_SSL_SESSION_bio(BIO *bio, SSL_SESSION **out);
+
+// ERR_load_SSL_strings does nothing.
+OPENSSL_EXPORT void ERR_load_SSL_strings(void);
+
+// SSL_load_error_strings does nothing.
+OPENSSL_EXPORT void SSL_load_error_strings(void);
+
+// SSL_CTX_set_tlsext_use_srtp calls |SSL_CTX_set_srtp_profiles|. It returns
+// zero on success and one on failure.
+//
+// WARNING: this function is dangerous because it breaks the usual return value
+// convention. Use |SSL_CTX_set_srtp_profiles| instead.
+OPENSSL_EXPORT int SSL_CTX_set_tlsext_use_srtp(SSL_CTX *ctx,
+                                               const char *profiles);
+
+// SSL_set_tlsext_use_srtp calls |SSL_set_srtp_profiles|. It returns zero on
+// success and one on failure.
+//
+// WARNING: this function is dangerous because it breaks the usual return value
+// convention. Use |SSL_set_srtp_profiles| instead.
+OPENSSL_EXPORT int SSL_set_tlsext_use_srtp(SSL *ssl, const char *profiles);
+
+// SSL_get_current_compression returns NULL.
+OPENSSL_EXPORT const COMP_METHOD *SSL_get_current_compression(SSL *ssl);
+
+// SSL_get_current_expansion returns NULL.
+OPENSSL_EXPORT const COMP_METHOD *SSL_get_current_expansion(SSL *ssl);
+
+// SSL_get_server_tmp_key returns zero.
+OPENSSL_EXPORT int SSL_get_server_tmp_key(SSL *ssl, EVP_PKEY **out_key);
+
+// SSL_CTX_set_tmp_dh returns 1.
+OPENSSL_EXPORT int SSL_CTX_set_tmp_dh(SSL_CTX *ctx, const DH *dh);
+
+// SSL_set_tmp_dh returns 1.
+OPENSSL_EXPORT int SSL_set_tmp_dh(SSL *ssl, const DH *dh);
+
+// SSL_CTX_set_tmp_dh_callback does nothing.
+OPENSSL_EXPORT void SSL_CTX_set_tmp_dh_callback(
+    SSL_CTX *ctx, DH *(*cb)(SSL *ssl, int is_export, int keylength));
+
+// SSL_set_tmp_dh_callback does nothing.
+OPENSSL_EXPORT void SSL_set_tmp_dh_callback(SSL *ssl,
+                                            DH *(*cb)(SSL *ssl, int is_export,
+                                                      int keylength));
+
+// SSL_CTX_set1_sigalgs takes |num_values| ints and interprets them as pairs
+// where the first is the nid of a hash function and the second is an
+// |EVP_PKEY_*| value. It configures the signature algorithm preferences for
+// |ctx| based on them and returns one on success or zero on error.
+//
+// This API is compatible with OpenSSL. However, BoringSSL-specific code should
+// prefer |SSL_CTX_set_signing_algorithm_prefs| because it's clearer and it's
+// more convenient to codesearch for specific algorithm values.
+OPENSSL_EXPORT int SSL_CTX_set1_sigalgs(SSL_CTX *ctx, const int *values,
+                                        size_t num_values);
+
+// SSL_set1_sigalgs takes |num_values| ints and interprets them as pairs where
+// the first is the nid of a hash function and the second is an |EVP_PKEY_*|
+// value. It configures the signature algorithm preferences for |ssl| based on
+// them and returns one on success or zero on error.
+//
+// This API is compatible with OpenSSL. However, BoringSSL-specific code should
+// prefer |SSL_CTX_set_signing_algorithm_prefs| because it's clearer and it's
+// more convenient to codesearch for specific algorithm values.
+OPENSSL_EXPORT int SSL_set1_sigalgs(SSL *ssl, const int *values,
+                                    size_t num_values);
+
+// SSL_CTX_set1_sigalgs_list takes a textual specification of a set of signature
+// algorithms and configures them on |ctx|. It returns one on success and zero
+// on error. See
+// https://www.openssl.org/docs/man1.1.0/man3/SSL_CTX_set1_sigalgs_list.html for
+// a description of the text format. Also note that TLS 1.3 names (e.g.
+// "rsa_pkcs1_md5_sha1") can also be used (as in OpenSSL, although OpenSSL
+// doesn't document that).
+//
+// This API is compatible with OpenSSL. However, BoringSSL-specific code should
+// prefer |SSL_CTX_set_signing_algorithm_prefs| because it's clearer and it's
+// more convenient to codesearch for specific algorithm values.
+OPENSSL_EXPORT int SSL_CTX_set1_sigalgs_list(SSL_CTX *ctx, const char *str);
+
+// SSL_set1_sigalgs_list takes a textual specification of a set of signature
+// algorithms and configures them on |ssl|. It returns one on success and zero
+// on error. See
+// https://www.openssl.org/docs/man1.1.0/man3/SSL_CTX_set1_sigalgs_list.html for
+// a description of the text format. Also note that TLS 1.3 names (e.g.
+// "rsa_pkcs1_md5_sha1") can also be used (as in OpenSSL, although OpenSSL
+// doesn't document that).
+//
+// This API is compatible with OpenSSL. However, BoringSSL-specific code should
+// prefer |SSL_CTX_set_signing_algorithm_prefs| because it's clearer and it's
+// more convenient to codesearch for specific algorithm values.
+OPENSSL_EXPORT int SSL_set1_sigalgs_list(SSL *ssl, const char *str);
+
+#define SSL_set_app_data(s, arg) (SSL_set_ex_data(s, 0, (char *)(arg)))
+#define SSL_get_app_data(s) (SSL_get_ex_data(s, 0))
+#define SSL_SESSION_set_app_data(s, a) \
+  (SSL_SESSION_set_ex_data(s, 0, (char *)(a)))
+#define SSL_SESSION_get_app_data(s) (SSL_SESSION_get_ex_data(s, 0))
+#define SSL_CTX_get_app_data(ctx) (SSL_CTX_get_ex_data(ctx, 0))
+#define SSL_CTX_set_app_data(ctx, arg) \
+  (SSL_CTX_set_ex_data(ctx, 0, (char *)(arg)))
+
+#define OpenSSL_add_ssl_algorithms() SSL_library_init()
+#define SSLeay_add_ssl_algorithms() SSL_library_init()
+
+#define SSL_get_cipher(ssl) SSL_CIPHER_get_name(SSL_get_current_cipher(ssl))
+#define SSL_get_cipher_bits(ssl, out_alg_bits) \
+    SSL_CIPHER_get_bits(SSL_get_current_cipher(ssl), out_alg_bits)
+#define SSL_get_cipher_version(ssl) \
+    SSL_CIPHER_get_version(SSL_get_current_cipher(ssl))
+#define SSL_get_cipher_name(ssl) \
+    SSL_CIPHER_get_name(SSL_get_current_cipher(ssl))
+#define SSL_get_time(session) SSL_SESSION_get_time(session)
+#define SSL_set_time(session, time) SSL_SESSION_set_time((session), (time))
+#define SSL_get_timeout(session) SSL_SESSION_get_timeout(session)
+#define SSL_set_timeout(session, timeout) \
+    SSL_SESSION_set_timeout((session), (timeout))
+
+struct ssl_comp_st {
+  int id;
+  const char *name;
+  char *method;
+};
+
+DEFINE_STACK_OF(SSL_COMP)
+
+// The following flags do nothing and are included only to make it easier to
+// compile code with BoringSSL.
+#define SSL_MODE_AUTO_RETRY 0
+#define SSL_MODE_RELEASE_BUFFERS 0
+#define SSL_MODE_SEND_CLIENTHELLO_TIME 0
+#define SSL_MODE_SEND_SERVERHELLO_TIME 0
+#define SSL_OP_ALL 0
+#define SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION 0
+#define SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS 0
+#define SSL_OP_EPHEMERAL_RSA 0
+#define SSL_OP_LEGACY_SERVER_CONNECT 0
+#define SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER 0
+#define SSL_OP_MICROSOFT_SESS_ID_BUG 0
+#define SSL_OP_MSIE_SSLV2_RSA_PADDING 0
+#define SSL_OP_NETSCAPE_CA_DN_BUG 0
+#define SSL_OP_NETSCAPE_CHALLENGE_BUG 0
+#define SSL_OP_NETSCAPE_DEMO_CIPHER_CHANGE_BUG 0
+#define SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG 0
+#define SSL_OP_NO_COMPRESSION 0
+#define SSL_OP_NO_RENEGOTIATION 0  // ssl_renegotiate_never is the default
+#define SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION 0
+#define SSL_OP_NO_SSLv2 0
+#define SSL_OP_NO_SSLv3 0
+#define SSL_OP_PKCS1_CHECK_1 0
+#define SSL_OP_PKCS1_CHECK_2 0
+#define SSL_OP_SINGLE_DH_USE 0
+#define SSL_OP_SINGLE_ECDH_USE 0
+#define SSL_OP_SSLEAY_080_CLIENT_DH_BUG 0
+#define SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG 0
+#define SSL_OP_TLS_BLOCK_PADDING_BUG 0
+#define SSL_OP_TLS_D5_BUG 0
+#define SSL_OP_TLS_ROLLBACK_BUG 0
+#define SSL_VERIFY_CLIENT_ONCE 0
+
+// SSL_cache_hit calls |SSL_session_reused|.
+OPENSSL_EXPORT int SSL_cache_hit(SSL *ssl);
+
+// SSL_get_default_timeout returns |SSL_DEFAULT_SESSION_TIMEOUT|.
+OPENSSL_EXPORT long SSL_get_default_timeout(const SSL *ssl);
+
+// SSL_get_version returns a string describing the TLS version used by |ssl|.
+// For example, "TLSv1.2" or "DTLSv1".
+OPENSSL_EXPORT const char *SSL_get_version(const SSL *ssl);
+
+// SSL_get_all_version_names outputs a list of possible strings
+// |SSL_get_version| may return in this version of BoringSSL. It writes at most
+// |max_out| entries to |out| and returns the total number it would have
+// written, if |max_out| had been large enough. |max_out| may be initially set
+// to zero to size the output.
+//
+// This function is only intended to help initialize tables in callers that want
+// possible strings pre-declared. This list would not be suitable to set a list
+// of supported features. It is in no particular order, and may contain
+// placeholder, experimental, or deprecated values that do not apply to every
+// caller. Future versions of BoringSSL may also return strings not in this
+// list, so this does not apply if, say, sending strings across services.
+OPENSSL_EXPORT size_t SSL_get_all_version_names(const char **out,
+                                                size_t max_out);
+
+// SSL_get_cipher_list returns the name of the |n|th cipher in the output of
+// |SSL_get_ciphers| or NULL if out of range. Use |SSL_get_ciphers| instead.
+OPENSSL_EXPORT const char *SSL_get_cipher_list(const SSL *ssl, int n);
+
+// SSL_CTX_set_client_cert_cb sets a callback which is called on the client if
+// the server requests a client certificate and none is configured. On success,
+// the callback should return one and set |*out_x509| to |*out_pkey| to a leaf
+// certificate and private key, respectively, passing ownership. It should
+// return zero to send no certificate and -1 to fail or pause the handshake. If
+// the handshake is paused, |SSL_get_error| will return
+// |SSL_ERROR_WANT_X509_LOOKUP|.
+//
+// The callback may call |SSL_get0_certificate_types| and
+// |SSL_get_client_CA_list| for information on the server's certificate request.
+//
+// Use |SSL_CTX_set_cert_cb| instead. Configuring intermediate certificates with
+// this function is confusing. This callback may not be registered concurrently
+// with |SSL_CTX_set_cert_cb| or |SSL_set_cert_cb|.
+OPENSSL_EXPORT void SSL_CTX_set_client_cert_cb(
+    SSL_CTX *ctx, int (*cb)(SSL *ssl, X509 **out_x509, EVP_PKEY **out_pkey));
+
+#define SSL_NOTHING SSL_ERROR_NONE
+#define SSL_WRITING SSL_ERROR_WANT_WRITE
+#define SSL_READING SSL_ERROR_WANT_READ
+
+// SSL_want returns one of the above values to determine what the most recent
+// operation on |ssl| was blocked on. Use |SSL_get_error| instead.
+OPENSSL_EXPORT int SSL_want(const SSL *ssl);
+
+#define SSL_want_read(ssl) (SSL_want(ssl) == SSL_READING)
+#define SSL_want_write(ssl) (SSL_want(ssl) == SSL_WRITING)
+
+ // SSL_get_finished writes up to |count| bytes of the Finished message sent by
+ // |ssl| to |buf|. It returns the total untruncated length or zero if none has
+ // been sent yet. At TLS 1.3 and later, it returns zero.
+ //
+ // Use |SSL_get_tls_unique| instead.
+OPENSSL_EXPORT size_t SSL_get_finished(const SSL *ssl, void *buf, size_t count);
+
+ // SSL_get_peer_finished writes up to |count| bytes of the Finished message
+ // received from |ssl|'s peer to |buf|. It returns the total untruncated length
+ // or zero if none has been received yet. At TLS 1.3 and later, it returns
+ // zero.
+ //
+ // Use |SSL_get_tls_unique| instead.
+OPENSSL_EXPORT size_t SSL_get_peer_finished(const SSL *ssl, void *buf,
+                                            size_t count);
+
+// SSL_alert_type_string returns "!". Use |SSL_alert_type_string_long|
+// instead.
+OPENSSL_EXPORT const char *SSL_alert_type_string(int value);
+
+// SSL_alert_desc_string returns "!!". Use |SSL_alert_desc_string_long|
+// instead.
+OPENSSL_EXPORT const char *SSL_alert_desc_string(int value);
+
+// SSL_state_string returns "!!!!!!". Use |SSL_state_string_long| for a more
+// intelligible string.
+OPENSSL_EXPORT const char *SSL_state_string(const SSL *ssl);
+
+// SSL_TXT_* expand to strings.
+#define SSL_TXT_MEDIUM "MEDIUM"
+#define SSL_TXT_HIGH "HIGH"
+#define SSL_TXT_FIPS "FIPS"
+#define SSL_TXT_kRSA "kRSA"
+#define SSL_TXT_kDHE "kDHE"
+#define SSL_TXT_kEDH "kEDH"
+#define SSL_TXT_kECDHE "kECDHE"
+#define SSL_TXT_kEECDH "kEECDH"
+#define SSL_TXT_kPSK "kPSK"
+#define SSL_TXT_aRSA "aRSA"
+#define SSL_TXT_aECDSA "aECDSA"
+#define SSL_TXT_aPSK "aPSK"
+#define SSL_TXT_DH "DH"
+#define SSL_TXT_DHE "DHE"
+#define SSL_TXT_EDH "EDH"
+#define SSL_TXT_RSA "RSA"
+#define SSL_TXT_ECDH "ECDH"
+#define SSL_TXT_ECDHE "ECDHE"
+#define SSL_TXT_EECDH "EECDH"
+#define SSL_TXT_ECDSA "ECDSA"
+#define SSL_TXT_PSK "PSK"
+#define SSL_TXT_3DES "3DES"
+#define SSL_TXT_RC4 "RC4"
+#define SSL_TXT_AES128 "AES128"
+#define SSL_TXT_AES256 "AES256"
+#define SSL_TXT_AES "AES"
+#define SSL_TXT_AES_GCM "AESGCM"
+#define SSL_TXT_CHACHA20 "CHACHA20"
+#define SSL_TXT_MD5 "MD5"
+#define SSL_TXT_SHA1 "SHA1"
+#define SSL_TXT_SHA "SHA"
+#define SSL_TXT_SHA256 "SHA256"
+#define SSL_TXT_SHA384 "SHA384"
+#define SSL_TXT_SSLV3 "SSLv3"
+#define SSL_TXT_TLSV1 "TLSv1"
+#define SSL_TXT_TLSV1_1 "TLSv1.1"
+#define SSL_TXT_TLSV1_2 "TLSv1.2"
+#define SSL_TXT_TLSV1_3 "TLSv1.3"
+#define SSL_TXT_ALL "ALL"
+#define SSL_TXT_CMPDEF "COMPLEMENTOFDEFAULT"
+
+typedef struct ssl_conf_ctx_st SSL_CONF_CTX;
+
+// SSL_state returns |SSL_ST_INIT| if a handshake is in progress and |SSL_ST_OK|
+// otherwise.
+//
+// Use |SSL_is_init| instead.
+OPENSSL_EXPORT int SSL_state(const SSL *ssl);
+
+#define SSL_get_state(ssl) SSL_state(ssl)
+
+// SSL_set_shutdown causes |ssl| to behave as if the shutdown bitmask (see
+// |SSL_get_shutdown|) were |mode|. This may be used to skip sending or
+// receiving close_notify in |SSL_shutdown| by causing the implementation to
+// believe the events already happened.
+//
+// It is an error to use |SSL_set_shutdown| to unset a bit that has already been
+// set. Doing so will trigger an |assert| in debug builds and otherwise be
+// ignored.
+//
+// Use |SSL_CTX_set_quiet_shutdown| instead.
+OPENSSL_EXPORT void SSL_set_shutdown(SSL *ssl, int mode);
+
+// SSL_CTX_set_tmp_ecdh calls |SSL_CTX_set1_groups| with a one-element list
+// containing |ec_key|'s curve. The remainder of |ec_key| is ignored.
+OPENSSL_EXPORT int SSL_CTX_set_tmp_ecdh(SSL_CTX *ctx, const EC_KEY *ec_key);
+
+// SSL_set_tmp_ecdh calls |SSL_set1_groups| with a one-element list containing
+// |ec_key|'s curve. The remainder of |ec_key| is ignored.
+OPENSSL_EXPORT int SSL_set_tmp_ecdh(SSL *ssl, const EC_KEY *ec_key);
+
+#if !defined(OPENSSL_NO_FILESYSTEM)
+// SSL_add_dir_cert_subjects_to_stack lists files in directory |dir|. It calls
+// |SSL_add_file_cert_subjects_to_stack| on each file and returns one on success
+// or zero on error. This function is only available from the libdecrepit
+// library.
+OPENSSL_EXPORT int SSL_add_dir_cert_subjects_to_stack(STACK_OF(X509_NAME) *out,
+                                                      const char *dir);
+#endif
+
+// SSL_CTX_enable_tls_channel_id calls |SSL_CTX_set_tls_channel_id_enabled|.
+OPENSSL_EXPORT int SSL_CTX_enable_tls_channel_id(SSL_CTX *ctx);
+
+// SSL_enable_tls_channel_id calls |SSL_set_tls_channel_id_enabled|.
+OPENSSL_EXPORT int SSL_enable_tls_channel_id(SSL *ssl);
+
+// BIO_f_ssl returns a |BIO_METHOD| that can wrap an |SSL*| in a |BIO*|. Note
+// that this has quite different behaviour from the version in OpenSSL (notably
+// that it doesn't try to auto renegotiate).
+//
+// IMPORTANT: if you are not curl, don't use this.
+OPENSSL_EXPORT const BIO_METHOD *BIO_f_ssl(void);
+
+// BIO_set_ssl sets |ssl| as the underlying connection for |bio|, which must
+// have been created using |BIO_f_ssl|. If |take_owership| is true, |bio| will
+// call |SSL_free| on |ssl| when closed. It returns one on success or something
+// other than one on error.
+OPENSSL_EXPORT long BIO_set_ssl(BIO *bio, SSL *ssl, int take_owership);
+
+// SSL_CTX_set_ecdh_auto returns one.
+#define SSL_CTX_set_ecdh_auto(ctx, onoff) 1
+
+// SSL_set_ecdh_auto returns one.
+#define SSL_set_ecdh_auto(ssl, onoff) 1
+
+// SSL_get_session returns a non-owning pointer to |ssl|'s session. For
+// historical reasons, which session it returns depends on |ssl|'s state.
+//
+// Prior to the start of the initial handshake, it returns the session the
+// caller set with |SSL_set_session|. After the initial handshake has finished
+// and if no additional handshakes are in progress, it returns the currently
+// active session. Its behavior is undefined while a handshake is in progress.
+//
+// If trying to add new sessions to an external session cache, use
+// |SSL_CTX_sess_set_new_cb| instead. In particular, using the callback is
+// required as of TLS 1.3. For compatibility, this function will return an
+// unresumable session which may be cached, but will never be resumed.
+//
+// If querying properties of the connection, use APIs on the |SSL| object.
+OPENSSL_EXPORT SSL_SESSION *SSL_get_session(const SSL *ssl);
+
+// SSL_get0_session is an alias for |SSL_get_session|.
+#define SSL_get0_session SSL_get_session
+
+// SSL_get1_session acts like |SSL_get_session| but returns a new reference to
+// the session.
+OPENSSL_EXPORT SSL_SESSION *SSL_get1_session(SSL *ssl);
+
+#define OPENSSL_INIT_NO_LOAD_SSL_STRINGS 0
+#define OPENSSL_INIT_LOAD_SSL_STRINGS 0
+#define OPENSSL_INIT_SSL_DEFAULT 0
+
+// OPENSSL_init_ssl calls |CRYPTO_library_init| and returns one.
+OPENSSL_EXPORT int OPENSSL_init_ssl(uint64_t opts,
+                                    const OPENSSL_INIT_SETTINGS *settings);
+
+// The following constants are legacy aliases for RSA-PSS with rsaEncryption
+// keys. Use the new names instead.
+#define SSL_SIGN_RSA_PSS_SHA256 SSL_SIGN_RSA_PSS_RSAE_SHA256
+#define SSL_SIGN_RSA_PSS_SHA384 SSL_SIGN_RSA_PSS_RSAE_SHA384
+#define SSL_SIGN_RSA_PSS_SHA512 SSL_SIGN_RSA_PSS_RSAE_SHA512
+
+// SSL_set_tlsext_status_type configures a client to request OCSP stapling if
+// |type| is |TLSEXT_STATUSTYPE_ocsp| and disables it otherwise. It returns one
+// on success and zero if handshake configuration has already been shed.
+//
+// Use |SSL_enable_ocsp_stapling| instead.
+OPENSSL_EXPORT int SSL_set_tlsext_status_type(SSL *ssl, int type);
+
+// SSL_get_tlsext_status_type returns |TLSEXT_STATUSTYPE_ocsp| if the client
+// requested OCSP stapling and |TLSEXT_STATUSTYPE_nothing| otherwise. On the
+// client, this reflects whether OCSP stapling was enabled via, e.g.,
+// |SSL_set_tlsext_status_type|. On the server, this is determined during the
+// handshake. It may be queried in callbacks set by |SSL_CTX_set_cert_cb|. The
+// result is undefined after the handshake completes.
+OPENSSL_EXPORT int SSL_get_tlsext_status_type(const SSL *ssl);
+
+// SSL_set_tlsext_status_ocsp_resp sets the OCSP response. It returns one on
+// success and zero on error. On success, |ssl| takes ownership of |resp|, which
+// must have been allocated by |OPENSSL_malloc|.
+//
+// Use |SSL_set_ocsp_response| instead.
+OPENSSL_EXPORT int SSL_set_tlsext_status_ocsp_resp(SSL *ssl, uint8_t *resp,
+                                                   size_t resp_len);
+
+// SSL_get_tlsext_status_ocsp_resp sets |*out| to point to the OCSP response
+// from the server. It returns the length of the response. If there was no
+// response, it sets |*out| to NULL and returns zero.
+//
+// Use |SSL_get0_ocsp_response| instead.
+//
+// WARNING: the returned data is not guaranteed to be well formed.
+OPENSSL_EXPORT size_t SSL_get_tlsext_status_ocsp_resp(const SSL *ssl,
+                                                      const uint8_t **out);
+
+// SSL_CTX_set_tlsext_status_cb configures the legacy OpenSSL OCSP callback and
+// returns one. Though the type signature is the same, this callback has
+// different behavior for client and server connections:
+//
+// For clients, the callback is called after certificate verification. It should
+// return one for success, zero for a bad OCSP response, and a negative number
+// for internal error. Instead, handle this as part of certificate verification.
+// (Historically, OpenSSL verified certificates just before parsing stapled OCSP
+// responses, but BoringSSL fixes this ordering. All server credentials are
+// available during verification.)
+//
+// Do not use this callback as a server. It is provided for compatibility
+// purposes only. For servers, it is called to configure server credentials. It
+// should return |SSL_TLSEXT_ERR_OK| on success, |SSL_TLSEXT_ERR_NOACK| to
+// ignore OCSP requests, or |SSL_TLSEXT_ERR_ALERT_FATAL| on error. It is usually
+// used to fetch OCSP responses on demand, which is not ideal. Instead, treat
+// OCSP responses like other server credentials, such as certificates or SCT
+// lists. Configure, store, and refresh them eagerly. This avoids downtime if
+// the CA's OCSP responder is briefly offline.
+OPENSSL_EXPORT int SSL_CTX_set_tlsext_status_cb(SSL_CTX *ctx,
+                                                int (*callback)(SSL *ssl,
+                                                                void *arg));
+
+// SSL_CTX_set_tlsext_status_arg sets additional data for
+// |SSL_CTX_set_tlsext_status_cb|'s callback and returns one.
+OPENSSL_EXPORT int SSL_CTX_set_tlsext_status_arg(SSL_CTX *ctx, void *arg);
+
+// The following symbols are compatibility aliases for reason codes used when
+// receiving an alert from the peer. Use the other names instead, which fit the
+// naming convention.
+//
+// TODO(davidben): Fix references to |SSL_R_TLSV1_CERTIFICATE_REQUIRED| and
+// remove the compatibility value. The others come from OpenSSL.
+#define SSL_R_TLSV1_UNSUPPORTED_EXTENSION \
+  SSL_R_TLSV1_ALERT_UNSUPPORTED_EXTENSION
+#define SSL_R_TLSV1_CERTIFICATE_UNOBTAINABLE \
+  SSL_R_TLSV1_ALERT_CERTIFICATE_UNOBTAINABLE
+#define SSL_R_TLSV1_UNRECOGNIZED_NAME SSL_R_TLSV1_ALERT_UNRECOGNIZED_NAME
+#define SSL_R_TLSV1_BAD_CERTIFICATE_STATUS_RESPONSE \
+  SSL_R_TLSV1_ALERT_BAD_CERTIFICATE_STATUS_RESPONSE
+#define SSL_R_TLSV1_BAD_CERTIFICATE_HASH_VALUE \
+  SSL_R_TLSV1_ALERT_BAD_CERTIFICATE_HASH_VALUE
+#define SSL_R_TLSV1_CERTIFICATE_REQUIRED SSL_R_TLSV1_ALERT_CERTIFICATE_REQUIRED
+
+// The following symbols are compatibility aliases for |SSL_GROUP_*|.
+#define SSL_CURVE_SECP224R1 SSL_GROUP_SECP224R1
+#define SSL_CURVE_SECP256R1 SSL_GROUP_SECP256R1
+#define SSL_CURVE_SECP384R1 SSL_GROUP_SECP384R1
+#define SSL_CURVE_SECP521R1 SSL_GROUP_SECP521R1
+#define SSL_CURVE_X25519 SSL_GROUP_X25519
+#define SSL_CURVE_X25519_KYBER768_DRAFT00 SSL_GROUP_X25519_KYBER768_DRAFT00
+
+// SSL_get_curve_id calls |SSL_get_group_id|.
+OPENSSL_EXPORT uint16_t SSL_get_curve_id(const SSL *ssl);
+
+// SSL_get_curve_name calls |SSL_get_group_name|.
+OPENSSL_EXPORT const char *SSL_get_curve_name(uint16_t curve_id);
+
+// SSL_get_all_curve_names calls |SSL_get_all_group_names|.
+OPENSSL_EXPORT size_t SSL_get_all_curve_names(const char **out, size_t max_out);
+
+// SSL_CTX_set1_curves calls |SSL_CTX_set1_groups|.
+OPENSSL_EXPORT int SSL_CTX_set1_curves(SSL_CTX *ctx, const int *curves,
+                                       size_t num_curves);
+
+// SSL_set1_curves calls |SSL_set1_groups|.
+OPENSSL_EXPORT int SSL_set1_curves(SSL *ssl, const int *curves,
+                                   size_t num_curves);
+
+// SSL_CTX_set1_curves_list calls |SSL_CTX_set1_groups_list|.
+OPENSSL_EXPORT int SSL_CTX_set1_curves_list(SSL_CTX *ctx, const char *curves);
+
+// SSL_set1_curves_list calls |SSL_set1_groups_list|.
+OPENSSL_EXPORT int SSL_set1_curves_list(SSL *ssl, const char *curves);
+
+// TLSEXT_nid_unknown is a constant used in OpenSSL for
+// |SSL_get_negotiated_group| to return an unrecognized group. BoringSSL never
+// returns this value, but we define this constant for compatibility.
+#define TLSEXT_nid_unknown 0x1000000
+
+// SSL_CTX_check_private_key returns one if |ctx| has both a certificate and
+// private key, and zero otherwise.
+//
+// This function does not check consistency because the library checks when the
+// certificate and key are individually configured. However, if the private key
+// is configured before the certificate, inconsistent private keys are silently
+// dropped. Some callers are inadvertently relying on this function to detect
+// when this happens.
+//
+// Instead, callers should configure the certificate first, then the private
+// key, checking for errors in each. This function is then unnecessary.
+OPENSSL_EXPORT int SSL_CTX_check_private_key(const SSL_CTX *ctx);
+
+// SSL_check_private_key returns one if |ssl| has both a certificate and private
+// key, and zero otherwise.
+//
+// See discussion in |SSL_CTX_check_private_key|.
+OPENSSL_EXPORT int SSL_check_private_key(const SSL *ssl);
+
+
+// Compliance policy configurations
+//
+// A TLS connection has a large number of different parameters. Some are well
+// known, like cipher suites, but many are obscure and configuration functions
+// for them may not exist. These policy controls allow broad configuration
+// goals to be specified so that they can flow down to all the different
+// parameters of a TLS connection.
+
+enum ssl_compliance_policy_t BORINGSSL_ENUM_INT {
+  // ssl_compliance_policy_none does nothing. However, since setting this
+  // doesn't undo other policies it's an error to try and set it.
+  ssl_compliance_policy_none,
+
+  // ssl_compliance_policy_fips_202205 configures a TLS connection to use:
+  //   * TLS 1.2 or 1.3
+  //   * For TLS 1.2, only ECDHE_[RSA|ECDSA]_WITH_AES_*_GCM_SHA*.
+  //   * For TLS 1.3, only AES-GCM
+  //   * P-256 or P-384 for key agreement.
+  //   * For server signatures, only PKCS#1/PSS with SHA256/384/512, or ECDSA
+  //     with P-256 or P-384.
+  //
+  // Note: this policy can be configured even if BoringSSL has not been built in
+  // FIPS mode. Call |FIPS_mode| to check that.
+  //
+  // Note: this setting aids with compliance with NIST requirements but does not
+  // guarantee it. Careful reading of SP 800-52r2 is recommended.
+  ssl_compliance_policy_fips_202205,
+
+  // ssl_compliance_policy_wpa3_192_202304 configures a TLS connection to use:
+  //   * TLS 1.2 or 1.3.
+  //   * For TLS 1.2, only TLS_ECDHE_[ECDSA|RSA]_WITH_AES_256_GCM_SHA384.
+  //   * For TLS 1.3, only AES-256-GCM.
+  //   * P-384 for key agreement.
+  //   * For handshake signatures, only ECDSA with P-384 and SHA-384, or RSA
+  //     with SHA-384 or SHA-512.
+  //
+  // No limitations on the certificate chain nor leaf public key are imposed,
+  // other than by the supported signature algorithms. But WPA3's "192-bit"
+  // mode requires at least P-384 or 3072-bit along the chain. The caller must
+  // enforce this themselves on the verified chain using functions such as
+  // `X509_STORE_CTX_get0_chain`.
+  //
+  // Note that this setting is less secure than the default. The
+  // implementation risks of using a more obscure primitive like P-384
+  // dominate other considerations.
+  ssl_compliance_policy_wpa3_192_202304,
+};
+
+// SSL_CTX_set_compliance_policy configures various aspects of |ctx| based on
+// the given policy requirements. Subsequently calling other functions that
+// configure |ctx| may override |policy|, or may not. This should be the final
+// configuration function called in order to have defined behaviour. It's a
+// fatal error if |policy| is |ssl_compliance_policy_none|.
+OPENSSL_EXPORT int SSL_CTX_set_compliance_policy(
+    SSL_CTX *ctx, enum ssl_compliance_policy_t policy);
+
+// SSL_set_compliance_policy acts the same as |SSL_CTX_set_compliance_policy|,
+// but only configures a single |SSL*|.
+OPENSSL_EXPORT int SSL_set_compliance_policy(
+    SSL *ssl, enum ssl_compliance_policy_t policy);
+
+
+// Nodejs compatibility section (hidden).
+//
+// These defines exist for node.js, with the hope that we can eliminate the
+// need for them over time.
+
+#define SSLerr(function, reason) \
+  ERR_put_error(ERR_LIB_SSL, 0, reason, __FILE__, __LINE__)
+
+
+// Preprocessor compatibility section (hidden).
+//
+// Historically, a number of APIs were implemented in OpenSSL as macros and
+// constants to 'ctrl' functions. To avoid breaking #ifdefs in consumers, this
+// section defines a number of legacy macros.
+//
+// Although using either the CTRL values or their wrapper macros in #ifdefs is
+// still supported, the CTRL values may not be passed to |SSL_ctrl| and
+// |SSL_CTX_ctrl|. Call the functions (previously wrapper macros) instead.
+//
+// See PORTING.md in the BoringSSL source tree for a table of corresponding
+// functions.
+// https://boringssl.googlesource.com/boringssl/+/master/PORTING.md#Replacements-for-values
+
+#define DTLS_CTRL_GET_TIMEOUT doesnt_exist
+#define DTLS_CTRL_HANDLE_TIMEOUT doesnt_exist
+#define SSL_CTRL_CHAIN doesnt_exist
+#define SSL_CTRL_CHAIN_CERT doesnt_exist
+#define SSL_CTRL_CHANNEL_ID doesnt_exist
+#define SSL_CTRL_CLEAR_EXTRA_CHAIN_CERTS doesnt_exist
+#define SSL_CTRL_CLEAR_MODE doesnt_exist
+#define SSL_CTRL_CLEAR_OPTIONS doesnt_exist
+#define SSL_CTRL_EXTRA_CHAIN_CERT doesnt_exist
+#define SSL_CTRL_GET_CHAIN_CERTS doesnt_exist
+#define SSL_CTRL_GET_CHANNEL_ID doesnt_exist
+#define SSL_CTRL_GET_CLIENT_CERT_TYPES doesnt_exist
+#define SSL_CTRL_GET_EXTRA_CHAIN_CERTS doesnt_exist
+#define SSL_CTRL_GET_MAX_CERT_LIST doesnt_exist
+#define SSL_CTRL_GET_NEGOTIATED_GROUP doesnt_exist
+#define SSL_CTRL_GET_NUM_RENEGOTIATIONS doesnt_exist
+#define SSL_CTRL_GET_READ_AHEAD doesnt_exist
+#define SSL_CTRL_GET_RI_SUPPORT doesnt_exist
+#define SSL_CTRL_GET_SERVER_TMP_KEY doesnt_exist
+#define SSL_CTRL_GET_SESSION_REUSED doesnt_exist
+#define SSL_CTRL_GET_SESS_CACHE_MODE doesnt_exist
+#define SSL_CTRL_GET_SESS_CACHE_SIZE doesnt_exist
+#define SSL_CTRL_GET_TLSEXT_TICKET_KEYS doesnt_exist
+#define SSL_CTRL_GET_TOTAL_RENEGOTIATIONS doesnt_exist
+#define SSL_CTRL_MODE doesnt_exist
+#define SSL_CTRL_NEED_TMP_RSA doesnt_exist
+#define SSL_CTRL_OPTIONS doesnt_exist
+#define SSL_CTRL_SESS_NUMBER doesnt_exist
+#define SSL_CTRL_SET_CURVES doesnt_exist
+#define SSL_CTRL_SET_CURVES_LIST doesnt_exist
+#define SSL_CTRL_SET_GROUPS doesnt_exist
+#define SSL_CTRL_SET_GROUPS_LIST doesnt_exist
+#define SSL_CTRL_SET_ECDH_AUTO doesnt_exist
+#define SSL_CTRL_SET_MAX_CERT_LIST doesnt_exist
+#define SSL_CTRL_SET_MAX_SEND_FRAGMENT doesnt_exist
+#define SSL_CTRL_SET_MSG_CALLBACK doesnt_exist
+#define SSL_CTRL_SET_MSG_CALLBACK_ARG doesnt_exist
+#define SSL_CTRL_SET_MTU doesnt_exist
+#define SSL_CTRL_SET_READ_AHEAD doesnt_exist
+#define SSL_CTRL_SET_SESS_CACHE_MODE doesnt_exist
+#define SSL_CTRL_SET_SESS_CACHE_SIZE doesnt_exist
+#define SSL_CTRL_SET_TLSEXT_HOSTNAME doesnt_exist
+#define SSL_CTRL_SET_TLSEXT_SERVERNAME_ARG doesnt_exist
+#define SSL_CTRL_SET_TLSEXT_SERVERNAME_CB doesnt_exist
+#define SSL_CTRL_SET_TLSEXT_TICKET_KEYS doesnt_exist
+#define SSL_CTRL_SET_TLSEXT_TICKET_KEY_CB doesnt_exist
+#define SSL_CTRL_SET_TMP_DH doesnt_exist
+#define SSL_CTRL_SET_TMP_DH_CB doesnt_exist
+#define SSL_CTRL_SET_TMP_ECDH doesnt_exist
+#define SSL_CTRL_SET_TMP_ECDH_CB doesnt_exist
+#define SSL_CTRL_SET_TMP_RSA doesnt_exist
+#define SSL_CTRL_SET_TMP_RSA_CB doesnt_exist
+
+// |BORINGSSL_PREFIX| already makes each of these symbols into macros, so there
+// is no need to define conflicting macros.
+#if !defined(BORINGSSL_PREFIX)
+
+#define DTLSv1_get_timeout DTLSv1_get_timeout
+#define DTLSv1_handle_timeout DTLSv1_handle_timeout
+#define SSL_CTX_add0_chain_cert SSL_CTX_add0_chain_cert
+#define SSL_CTX_add1_chain_cert SSL_CTX_add1_chain_cert
+#define SSL_CTX_add_extra_chain_cert SSL_CTX_add_extra_chain_cert
+#define SSL_CTX_clear_extra_chain_certs SSL_CTX_clear_extra_chain_certs
+#define SSL_CTX_clear_chain_certs SSL_CTX_clear_chain_certs
+#define SSL_CTX_clear_mode SSL_CTX_clear_mode
+#define SSL_CTX_clear_options SSL_CTX_clear_options
+#define SSL_CTX_get0_chain_certs SSL_CTX_get0_chain_certs
+#define SSL_CTX_get_extra_chain_certs SSL_CTX_get_extra_chain_certs
+#define SSL_CTX_get_max_cert_list SSL_CTX_get_max_cert_list
+#define SSL_CTX_get_mode SSL_CTX_get_mode
+#define SSL_CTX_get_options SSL_CTX_get_options
+#define SSL_CTX_get_read_ahead SSL_CTX_get_read_ahead
+#define SSL_CTX_get_session_cache_mode SSL_CTX_get_session_cache_mode
+#define SSL_CTX_get_tlsext_ticket_keys SSL_CTX_get_tlsext_ticket_keys
+#define SSL_CTX_need_tmp_RSA SSL_CTX_need_tmp_RSA
+#define SSL_CTX_sess_get_cache_size SSL_CTX_sess_get_cache_size
+#define SSL_CTX_sess_number SSL_CTX_sess_number
+#define SSL_CTX_sess_set_cache_size SSL_CTX_sess_set_cache_size
+#define SSL_CTX_set0_chain SSL_CTX_set0_chain
+#define SSL_CTX_set1_chain SSL_CTX_set1_chain
+#define SSL_CTX_set1_curves SSL_CTX_set1_curves
+#define SSL_CTX_set1_groups SSL_CTX_set1_groups
+#define SSL_CTX_set_max_cert_list SSL_CTX_set_max_cert_list
+#define SSL_CTX_set_max_send_fragment SSL_CTX_set_max_send_fragment
+#define SSL_CTX_set_mode SSL_CTX_set_mode
+#define SSL_CTX_set_msg_callback_arg SSL_CTX_set_msg_callback_arg
+#define SSL_CTX_set_options SSL_CTX_set_options
+#define SSL_CTX_set_read_ahead SSL_CTX_set_read_ahead
+#define SSL_CTX_set_session_cache_mode SSL_CTX_set_session_cache_mode
+#define SSL_CTX_set_tlsext_servername_arg SSL_CTX_set_tlsext_servername_arg
+#define SSL_CTX_set_tlsext_servername_callback \
+    SSL_CTX_set_tlsext_servername_callback
+#define SSL_CTX_set_tlsext_ticket_key_cb SSL_CTX_set_tlsext_ticket_key_cb
+#define SSL_CTX_set_tlsext_ticket_keys SSL_CTX_set_tlsext_ticket_keys
+#define SSL_CTX_set_tmp_dh SSL_CTX_set_tmp_dh
+#define SSL_CTX_set_tmp_ecdh SSL_CTX_set_tmp_ecdh
+#define SSL_CTX_set_tmp_rsa SSL_CTX_set_tmp_rsa
+#define SSL_add0_chain_cert SSL_add0_chain_cert
+#define SSL_add1_chain_cert SSL_add1_chain_cert
+#define SSL_clear_chain_certs SSL_clear_chain_certs
+#define SSL_clear_mode SSL_clear_mode
+#define SSL_clear_options SSL_clear_options
+#define SSL_get0_certificate_types SSL_get0_certificate_types
+#define SSL_get0_chain_certs SSL_get0_chain_certs
+#define SSL_get_max_cert_list SSL_get_max_cert_list
+#define SSL_get_mode SSL_get_mode
+#define SSL_get_negotiated_group SSL_get_negotiated_group
+#define SSL_get_options SSL_get_options
+#define SSL_get_secure_renegotiation_support \
+    SSL_get_secure_renegotiation_support
+#define SSL_need_tmp_RSA SSL_need_tmp_RSA
+#define SSL_num_renegotiations SSL_num_renegotiations
+#define SSL_session_reused SSL_session_reused
+#define SSL_set0_chain SSL_set0_chain
+#define SSL_set1_chain SSL_set1_chain
+#define SSL_set1_curves SSL_set1_curves
+#define SSL_set1_groups SSL_set1_groups
+#define SSL_set_max_cert_list SSL_set_max_cert_list
+#define SSL_set_max_send_fragment SSL_set_max_send_fragment
+#define SSL_set_mode SSL_set_mode
+#define SSL_set_msg_callback_arg SSL_set_msg_callback_arg
+#define SSL_set_mtu SSL_set_mtu
+#define SSL_set_options SSL_set_options
+#define SSL_set_tlsext_host_name SSL_set_tlsext_host_name
+#define SSL_set_tmp_dh SSL_set_tmp_dh
+#define SSL_set_tmp_ecdh SSL_set_tmp_ecdh
+#define SSL_set_tmp_rsa SSL_set_tmp_rsa
+#define SSL_total_renegotiations SSL_total_renegotiations
+
+#endif // !defined(BORINGSSL_PREFIX)
+
+
+#if defined(__cplusplus)
+}  // extern C
+
+#if !defined(BORINGSSL_NO_CXX)
+
+extern "C++" {
+
+BSSL_NAMESPACE_BEGIN
+
+BORINGSSL_MAKE_DELETER(SSL, SSL_free)
+BORINGSSL_MAKE_DELETER(SSL_CREDENTIAL, SSL_CREDENTIAL_free)
+BORINGSSL_MAKE_UP_REF(SSL_CREDENTIAL, SSL_CREDENTIAL_up_ref)
+BORINGSSL_MAKE_DELETER(SSL_CTX, SSL_CTX_free)
+BORINGSSL_MAKE_UP_REF(SSL_CTX, SSL_CTX_up_ref)
+BORINGSSL_MAKE_DELETER(SSL_ECH_KEYS, SSL_ECH_KEYS_free)
+BORINGSSL_MAKE_UP_REF(SSL_ECH_KEYS, SSL_ECH_KEYS_up_ref)
+BORINGSSL_MAKE_DELETER(SSL_SESSION, SSL_SESSION_free)
+BORINGSSL_MAKE_UP_REF(SSL_SESSION, SSL_SESSION_up_ref)
+
+
+// *** DEPRECATED EXPERIMENT — DO NOT USE ***
+//
+// Split handshakes.
+//
+// WARNING: This mechanism is deprecated and should not be used. It is very
+// fragile and difficult to use correctly. The relationship between
+// configuration options across the two halves is ill-defined and not
+// self-consistent. Additionally, version skew across the two halves risks
+// unusual behavior and connection failure. New development should use the
+// handshake hints API. Existing deployments should migrate to handshake hints
+// to reduce the risk of service outages.
+//
+// Split handshakes allows the handshake part of a TLS connection to be
+// performed in a different process (or on a different machine) than the data
+// exchange. This only applies to servers.
+//
+// In the first part of a split handshake, an |SSL| (where the |SSL_CTX| has
+// been configured with |SSL_CTX_set_handoff_mode|) is used normally. Once the
+// ClientHello message has been received, the handshake will stop and
+// |SSL_get_error| will indicate |SSL_ERROR_HANDOFF|. At this point (and only
+// at this point), |SSL_serialize_handoff| can be called to write the “handoff”
+// state of the connection.
+//
+// Elsewhere, a fresh |SSL| can be used with |SSL_apply_handoff| to continue
+// the connection. The connection from the client is fed into this |SSL|, and
+// the handshake resumed. When the handshake stops again and |SSL_get_error|
+// indicates |SSL_ERROR_HANDBACK|, |SSL_serialize_handback| should be called to
+// serialize the state of the handshake again.
+//
+// Back at the first location, a fresh |SSL| can be used with
+// |SSL_apply_handback|. Then the client's connection can be processed mostly
+// as normal.
+//
+// Lastly, when a connection is in the handoff state, whether or not
+// |SSL_serialize_handoff| is called, |SSL_decline_handoff| will move it back
+// into a normal state where the connection can proceed without impact.
+//
+// WARNING: Currently only works with TLS 1.0–1.2.
+// WARNING: The serialisation formats are not yet stable: version skew may be
+//     fatal.
+// WARNING: The handback data contains sensitive key material and must be
+//     protected.
+// WARNING: Some calls on the final |SSL| will not work. Just as an example,
+//     calls like |SSL_get0_session_id_context| and |SSL_get_privatekey| won't
+//     work because the certificate used for handshaking isn't available.
+// WARNING: |SSL_apply_handoff| may trigger “msg” callback calls.
+
+OPENSSL_EXPORT void SSL_CTX_set_handoff_mode(SSL_CTX *ctx, bool on);
+OPENSSL_EXPORT void SSL_set_handoff_mode(SSL *SSL, bool on);
+OPENSSL_EXPORT bool SSL_serialize_handoff(const SSL *ssl, CBB *out,
+                                          SSL_CLIENT_HELLO *out_hello);
+OPENSSL_EXPORT bool SSL_decline_handoff(SSL *ssl);
+OPENSSL_EXPORT bool SSL_apply_handoff(SSL *ssl, Span<const uint8_t> handoff);
+OPENSSL_EXPORT bool SSL_serialize_handback(const SSL *ssl, CBB *out);
+OPENSSL_EXPORT bool SSL_apply_handback(SSL *ssl, Span<const uint8_t> handback);
+
+// SSL_get_traffic_secrets sets |*out_read_traffic_secret| and
+// |*out_write_traffic_secret| to reference the TLS 1.3 traffic secrets for
+// |ssl|. This function is only valid on TLS 1.3 connections that have
+// completed the handshake. It returns true on success and false on error.
+OPENSSL_EXPORT bool SSL_get_traffic_secrets(
+    const SSL *ssl, Span<const uint8_t> *out_read_traffic_secret,
+    Span<const uint8_t> *out_write_traffic_secret);
+
+// SSL_CTX_set_aes_hw_override_for_testing sets |override_value| to
+// override checking for aes hardware support for testing. If |override_value|
+// is set to true, the library will behave as if aes hardware support is
+// present. If it is set to false, the library will behave as if aes hardware
+// support is not present.
+OPENSSL_EXPORT void SSL_CTX_set_aes_hw_override_for_testing(
+    SSL_CTX *ctx, bool override_value);
+
+// SSL_set_aes_hw_override_for_testing acts the same as
+// |SSL_CTX_set_aes_override_for_testing| but only configures a single |SSL*|.
+OPENSSL_EXPORT void SSL_set_aes_hw_override_for_testing(SSL *ssl,
+                                                        bool override_value);
+
+BSSL_NAMESPACE_END
+
+}  // extern C++
+
+#endif  // !defined(BORINGSSL_NO_CXX)
+
+#endif
+
+#define SSL_R_APP_DATA_IN_HANDSHAKE 100
+#define SSL_R_ATTEMPT_TO_REUSE_SESSION_IN_DIFFERENT_CONTEXT 101
+#define SSL_R_BAD_ALERT 102
+#define SSL_R_BAD_CHANGE_CIPHER_SPEC 103
+#define SSL_R_BAD_DATA_RETURNED_BY_CALLBACK 104
+#define SSL_R_BAD_DH_P_LENGTH 105
+#define SSL_R_BAD_DIGEST_LENGTH 106
+#define SSL_R_BAD_ECC_CERT 107
+#define SSL_R_BAD_ECPOINT 108
+#define SSL_R_BAD_HANDSHAKE_RECORD 109
+#define SSL_R_BAD_HELLO_REQUEST 110
+#define SSL_R_BAD_LENGTH 111
+#define SSL_R_BAD_PACKET_LENGTH 112
+#define SSL_R_BAD_RSA_ENCRYPT 113
+#define SSL_R_BAD_SIGNATURE 114
+#define SSL_R_BAD_SRTP_MKI_VALUE 115
+#define SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST 116
+#define SSL_R_BAD_SSL_FILETYPE 117
+#define SSL_R_BAD_WRITE_RETRY 118
+#define SSL_R_BIO_NOT_SET 119
+#define SSL_R_BN_LIB 120
+#define SSL_R_BUFFER_TOO_SMALL 121
+#define SSL_R_CA_DN_LENGTH_MISMATCH 122
+#define SSL_R_CA_DN_TOO_LONG 123
+#define SSL_R_CCS_RECEIVED_EARLY 124
+#define SSL_R_CERTIFICATE_VERIFY_FAILED 125
+#define SSL_R_CERT_CB_ERROR 126
+#define SSL_R_CERT_LENGTH_MISMATCH 127
+#define SSL_R_CHANNEL_ID_NOT_P256 128
+#define SSL_R_CHANNEL_ID_SIGNATURE_INVALID 129
+#define SSL_R_CIPHER_OR_HASH_UNAVAILABLE 130
+#define SSL_R_CLIENTHELLO_PARSE_FAILED 131
+#define SSL_R_CLIENTHELLO_TLSEXT 132
+#define SSL_R_CONNECTION_REJECTED 133
+#define SSL_R_CONNECTION_TYPE_NOT_SET 134
+#define SSL_R_CUSTOM_EXTENSION_ERROR 135
+#define SSL_R_DATA_LENGTH_TOO_LONG 136
+#define SSL_R_DECODE_ERROR 137
+#define SSL_R_DECRYPTION_FAILED 138
+#define SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC 139
+#define SSL_R_DH_PUBLIC_VALUE_LENGTH_IS_WRONG 140
+#define SSL_R_DH_P_TOO_LONG 141
+#define SSL_R_DIGEST_CHECK_FAILED 142
+#define SSL_R_DTLS_MESSAGE_TOO_BIG 143
+#define SSL_R_ECC_CERT_NOT_FOR_SIGNING 144
+#define SSL_R_EMS_STATE_INCONSISTENT 145
+#define SSL_R_ENCRYPTED_LENGTH_TOO_LONG 146
+#define SSL_R_ERROR_ADDING_EXTENSION 147
+#define SSL_R_ERROR_IN_RECEIVED_CIPHER_LIST 148
+#define SSL_R_ERROR_PARSING_EXTENSION 149
+#define SSL_R_EXCESSIVE_MESSAGE_SIZE 150
+#define SSL_R_EXTRA_DATA_IN_MESSAGE 151
+#define SSL_R_FRAGMENT_MISMATCH 152
+#define SSL_R_GOT_NEXT_PROTO_WITHOUT_EXTENSION 153
+#define SSL_R_HANDSHAKE_FAILURE_ON_CLIENT_HELLO 154
+#define SSL_R_HTTPS_PROXY_REQUEST 155
+#define SSL_R_HTTP_REQUEST 156
+#define SSL_R_INAPPROPRIATE_FALLBACK 157
+#define SSL_R_INVALID_COMMAND 158
+#define SSL_R_INVALID_MESSAGE 159
+#define SSL_R_INVALID_SSL_SESSION 160
+#define SSL_R_INVALID_TICKET_KEYS_LENGTH 161
+#define SSL_R_LENGTH_MISMATCH 162
+#define SSL_R_MISSING_EXTENSION 164
+#define SSL_R_MISSING_RSA_CERTIFICATE 165
+#define SSL_R_MISSING_TMP_DH_KEY 166
+#define SSL_R_MISSING_TMP_ECDH_KEY 167
+#define SSL_R_MIXED_SPECIAL_OPERATOR_WITH_GROUPS 168
+#define SSL_R_MTU_TOO_SMALL 169
+#define SSL_R_NEGOTIATED_BOTH_NPN_AND_ALPN 170
+#define SSL_R_NESTED_GROUP 171
+#define SSL_R_NO_CERTIFICATES_RETURNED 172
+#define SSL_R_NO_CERTIFICATE_ASSIGNED 173
+#define SSL_R_NO_CERTIFICATE_SET 174
+#define SSL_R_NO_CIPHERS_AVAILABLE 175
+#define SSL_R_NO_CIPHERS_PASSED 176
+#define SSL_R_NO_CIPHER_MATCH 177
+#define SSL_R_NO_COMPRESSION_SPECIFIED 178
+#define SSL_R_NO_METHOD_SPECIFIED 179
+#define SSL_R_NO_PRIVATE_KEY_ASSIGNED 181
+#define SSL_R_NO_RENEGOTIATION 182
+#define SSL_R_NO_REQUIRED_DIGEST 183
+#define SSL_R_NO_SHARED_CIPHER 184
+#define SSL_R_NULL_SSL_CTX 185
+#define SSL_R_NULL_SSL_METHOD_PASSED 186
+#define SSL_R_OLD_SESSION_CIPHER_NOT_RETURNED 187
+#define SSL_R_OLD_SESSION_VERSION_NOT_RETURNED 188
+#define SSL_R_OUTPUT_ALIASES_INPUT 189
+#define SSL_R_PARSE_TLSEXT 190
+#define SSL_R_PATH_TOO_LONG 191
+#define SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE 192
+#define SSL_R_PEER_ERROR_UNSUPPORTED_CERTIFICATE_TYPE 193
+#define SSL_R_PROTOCOL_IS_SHUTDOWN 194
+#define SSL_R_PSK_IDENTITY_NOT_FOUND 195
+#define SSL_R_PSK_NO_CLIENT_CB 196
+#define SSL_R_PSK_NO_SERVER_CB 197
+#define SSL_R_READ_TIMEOUT_EXPIRED 198
+#define SSL_R_RECORD_LENGTH_MISMATCH 199
+#define SSL_R_RECORD_TOO_LARGE 200
+#define SSL_R_RENEGOTIATION_ENCODING_ERR 201
+#define SSL_R_RENEGOTIATION_MISMATCH 202
+#define SSL_R_REQUIRED_CIPHER_MISSING 203
+#define SSL_R_RESUMED_EMS_SESSION_WITHOUT_EMS_EXTENSION 204
+#define SSL_R_RESUMED_NON_EMS_SESSION_WITH_EMS_EXTENSION 205
+#define SSL_R_SCSV_RECEIVED_WHEN_RENEGOTIATING 206
+#define SSL_R_SERVERHELLO_TLSEXT 207
+#define SSL_R_SESSION_ID_CONTEXT_UNINITIALIZED 208
+#define SSL_R_SESSION_MAY_NOT_BE_CREATED 209
+#define SSL_R_SIGNATURE_ALGORITHMS_EXTENSION_SENT_BY_SERVER 210
+#define SSL_R_SRTP_COULD_NOT_ALLOCATE_PROFILES 211
+#define SSL_R_SRTP_UNKNOWN_PROTECTION_PROFILE 212
+#define SSL_R_SSL3_EXT_INVALID_SERVERNAME 213
+#define SSL_R_SSL_CTX_HAS_NO_DEFAULT_SSL_VERSION 214
+#define SSL_R_SSL_HANDSHAKE_FAILURE 215
+#define SSL_R_SSL_SESSION_ID_CONTEXT_TOO_LONG 216
+#define SSL_R_TLS_PEER_DID_NOT_RESPOND_WITH_CERTIFICATE_LIST 217
+#define SSL_R_TLS_RSA_ENCRYPTED_VALUE_LENGTH_IS_WRONG 218
+#define SSL_R_TOO_MANY_EMPTY_FRAGMENTS 219
+#define SSL_R_TOO_MANY_WARNING_ALERTS 220
+#define SSL_R_UNABLE_TO_FIND_ECDH_PARAMETERS 221
+#define SSL_R_UNEXPECTED_EXTENSION 222
+#define SSL_R_UNEXPECTED_MESSAGE 223
+#define SSL_R_UNEXPECTED_OPERATOR_IN_GROUP 224
+#define SSL_R_UNEXPECTED_RECORD 225
+#define SSL_R_UNINITIALIZED 226
+#define SSL_R_UNKNOWN_ALERT_TYPE 227
+#define SSL_R_UNKNOWN_CERTIFICATE_TYPE 228
+#define SSL_R_UNKNOWN_CIPHER_RETURNED 229
+#define SSL_R_UNKNOWN_CIPHER_TYPE 230
+#define SSL_R_UNKNOWN_DIGEST 231
+#define SSL_R_UNKNOWN_KEY_EXCHANGE_TYPE 232
+#define SSL_R_UNKNOWN_PROTOCOL 233
+#define SSL_R_UNKNOWN_SSL_VERSION 234
+#define SSL_R_UNKNOWN_STATE 235
+#define SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED 236
+#define SSL_R_UNSUPPORTED_CIPHER 237
+#define SSL_R_UNSUPPORTED_COMPRESSION_ALGORITHM 238
+#define SSL_R_UNSUPPORTED_ELLIPTIC_CURVE 239
+#define SSL_R_UNSUPPORTED_PROTOCOL 240
+#define SSL_R_WRONG_CERTIFICATE_TYPE 241
+#define SSL_R_WRONG_CIPHER_RETURNED 242
+#define SSL_R_WRONG_CURVE 243
+#define SSL_R_WRONG_MESSAGE_TYPE 244
+#define SSL_R_WRONG_SIGNATURE_TYPE 245
+#define SSL_R_WRONG_SSL_VERSION 246
+#define SSL_R_WRONG_VERSION_NUMBER 247
+#define SSL_R_X509_LIB 248
+#define SSL_R_X509_VERIFICATION_SETUP_PROBLEMS 249
+#define SSL_R_SHUTDOWN_WHILE_IN_INIT 250
+#define SSL_R_INVALID_OUTER_RECORD_TYPE 251
+#define SSL_R_UNSUPPORTED_PROTOCOL_FOR_CUSTOM_KEY 252
+#define SSL_R_NO_COMMON_SIGNATURE_ALGORITHMS 253
+#define SSL_R_DOWNGRADE_DETECTED 254
+#define SSL_R_EXCESS_HANDSHAKE_DATA 255
+#define SSL_R_INVALID_COMPRESSION_LIST 256
+#define SSL_R_DUPLICATE_EXTENSION 257
+#define SSL_R_MISSING_KEY_SHARE 258
+#define SSL_R_INVALID_ALPN_PROTOCOL 259
+#define SSL_R_TOO_MANY_KEY_UPDATES 260
+#define SSL_R_BLOCK_CIPHER_PAD_IS_WRONG 261
+#define SSL_R_NO_CIPHERS_SPECIFIED 262
+#define SSL_R_RENEGOTIATION_EMS_MISMATCH 263
+#define SSL_R_DUPLICATE_KEY_SHARE 264
+#define SSL_R_NO_GROUPS_SPECIFIED 265
+#define SSL_R_NO_SHARED_GROUP 266
+#define SSL_R_PRE_SHARED_KEY_MUST_BE_LAST 267
+#define SSL_R_OLD_SESSION_PRF_HASH_MISMATCH 268
+#define SSL_R_INVALID_SCT_LIST 269
+#define SSL_R_TOO_MUCH_SKIPPED_EARLY_DATA 270
+#define SSL_R_PSK_IDENTITY_BINDER_COUNT_MISMATCH 271
+#define SSL_R_CANNOT_PARSE_LEAF_CERT 272
+#define SSL_R_SERVER_CERT_CHANGED 273
+#define SSL_R_CERTIFICATE_AND_PRIVATE_KEY_MISMATCH 274
+#define SSL_R_CANNOT_HAVE_BOTH_PRIVKEY_AND_METHOD 275
+#define SSL_R_TICKET_ENCRYPTION_FAILED 276
+#define SSL_R_ALPN_MISMATCH_ON_EARLY_DATA 277
+#define SSL_R_WRONG_VERSION_ON_EARLY_DATA 278
+#define SSL_R_UNEXPECTED_EXTENSION_ON_EARLY_DATA 279
+#define SSL_R_NO_SUPPORTED_VERSIONS_ENABLED 280
+#define SSL_R_APPLICATION_DATA_INSTEAD_OF_HANDSHAKE 281
+#define SSL_R_EMPTY_HELLO_RETRY_REQUEST 282
+#define SSL_R_EARLY_DATA_NOT_IN_USE 283
+#define SSL_R_HANDSHAKE_NOT_COMPLETE 284
+#define SSL_R_NEGOTIATED_TB_WITHOUT_EMS_OR_RI 285
+#define SSL_R_SERVER_ECHOED_INVALID_SESSION_ID 286
+#define SSL_R_PRIVATE_KEY_OPERATION_FAILED 287
+#define SSL_R_SECOND_SERVERHELLO_VERSION_MISMATCH 288
+#define SSL_R_OCSP_CB_ERROR 289
+#define SSL_R_SSL_SESSION_ID_TOO_LONG 290
+#define SSL_R_APPLICATION_DATA_ON_SHUTDOWN 291
+#define SSL_R_CERT_DECOMPRESSION_FAILED 292
+#define SSL_R_UNCOMPRESSED_CERT_TOO_LARGE 293
+#define SSL_R_UNKNOWN_CERT_COMPRESSION_ALG 294
+#define SSL_R_INVALID_SIGNATURE_ALGORITHM 295
+#define SSL_R_DUPLICATE_SIGNATURE_ALGORITHM 296
+#define SSL_R_TLS13_DOWNGRADE 297
+#define SSL_R_QUIC_INTERNAL_ERROR 298
+#define SSL_R_WRONG_ENCRYPTION_LEVEL_RECEIVED 299
+#define SSL_R_TOO_MUCH_READ_EARLY_DATA 300
+#define SSL_R_INVALID_DELEGATED_CREDENTIAL 301
+#define SSL_R_KEY_USAGE_BIT_INCORRECT 302
+#define SSL_R_INCONSISTENT_CLIENT_HELLO 303
+#define SSL_R_CIPHER_MISMATCH_ON_EARLY_DATA 304
+#define SSL_R_QUIC_TRANSPORT_PARAMETERS_MISCONFIGURED 305
+#define SSL_R_UNEXPECTED_COMPATIBILITY_MODE 306
+#define SSL_R_NO_APPLICATION_PROTOCOL 307
+#define SSL_R_NEGOTIATED_ALPS_WITHOUT_ALPN 308
+#define SSL_R_ALPS_MISMATCH_ON_EARLY_DATA 309
+#define SSL_R_ECH_SERVER_CONFIG_AND_PRIVATE_KEY_MISMATCH 310
+#define SSL_R_ECH_SERVER_CONFIG_UNSUPPORTED_EXTENSION 311
+#define SSL_R_UNSUPPORTED_ECH_SERVER_CONFIG 312
+#define SSL_R_ECH_SERVER_WOULD_HAVE_NO_RETRY_CONFIGS 313
+#define SSL_R_INVALID_CLIENT_HELLO_INNER 314
+#define SSL_R_INVALID_ALPN_PROTOCOL_LIST 315
+#define SSL_R_COULD_NOT_PARSE_HINTS 316
+#define SSL_R_INVALID_ECH_PUBLIC_NAME 317
+#define SSL_R_INVALID_ECH_CONFIG_LIST 318
+#define SSL_R_ECH_REJECTED 319
+#define SSL_R_INVALID_OUTER_EXTENSION 320
+#define SSL_R_INCONSISTENT_ECH_NEGOTIATION 321
+#define SSL_R_INVALID_ALPS_CODEPOINT 322
+#define SSL_R_SSLV3_ALERT_CLOSE_NOTIFY 1000
+#define SSL_R_SSLV3_ALERT_UNEXPECTED_MESSAGE 1010
+#define SSL_R_SSLV3_ALERT_BAD_RECORD_MAC 1020
+#define SSL_R_TLSV1_ALERT_DECRYPTION_FAILED 1021
+#define SSL_R_TLSV1_ALERT_RECORD_OVERFLOW 1022
+#define SSL_R_SSLV3_ALERT_DECOMPRESSION_FAILURE 1030
+#define SSL_R_SSLV3_ALERT_HANDSHAKE_FAILURE 1040
+#define SSL_R_SSLV3_ALERT_NO_CERTIFICATE 1041
+#define SSL_R_SSLV3_ALERT_BAD_CERTIFICATE 1042
+#define SSL_R_SSLV3_ALERT_UNSUPPORTED_CERTIFICATE 1043
+#define SSL_R_SSLV3_ALERT_CERTIFICATE_REVOKED 1044
+#define SSL_R_SSLV3_ALERT_CERTIFICATE_EXPIRED 1045
+#define SSL_R_SSLV3_ALERT_CERTIFICATE_UNKNOWN 1046
+#define SSL_R_SSLV3_ALERT_ILLEGAL_PARAMETER 1047
+#define SSL_R_TLSV1_ALERT_UNKNOWN_CA 1048
+#define SSL_R_TLSV1_ALERT_ACCESS_DENIED 1049
+#define SSL_R_TLSV1_ALERT_DECODE_ERROR 1050
+#define SSL_R_TLSV1_ALERT_DECRYPT_ERROR 1051
+#define SSL_R_TLSV1_ALERT_EXPORT_RESTRICTION 1060
+#define SSL_R_TLSV1_ALERT_PROTOCOL_VERSION 1070
+#define SSL_R_TLSV1_ALERT_INSUFFICIENT_SECURITY 1071
+#define SSL_R_TLSV1_ALERT_INTERNAL_ERROR 1080
+#define SSL_R_TLSV1_ALERT_INAPPROPRIATE_FALLBACK 1086
+#define SSL_R_TLSV1_ALERT_USER_CANCELLED 1090
+#define SSL_R_TLSV1_ALERT_NO_RENEGOTIATION 1100
+#define SSL_R_TLSV1_ALERT_UNSUPPORTED_EXTENSION 1110
+#define SSL_R_TLSV1_ALERT_CERTIFICATE_UNOBTAINABLE 1111
+#define SSL_R_TLSV1_ALERT_UNRECOGNIZED_NAME 1112
+#define SSL_R_TLSV1_ALERT_BAD_CERTIFICATE_STATUS_RESPONSE 1113
+#define SSL_R_TLSV1_ALERT_BAD_CERTIFICATE_HASH_VALUE 1114
+#define SSL_R_TLSV1_ALERT_UNKNOWN_PSK_IDENTITY 1115
+#define SSL_R_TLSV1_ALERT_CERTIFICATE_REQUIRED 1116
+#define SSL_R_TLSV1_ALERT_NO_APPLICATION_PROTOCOL 1120
+#define SSL_R_TLSV1_ALERT_ECH_REQUIRED 1121
+
+#endif  // OPENSSL_HEADER_SSL_H