Update contrib/libs/nghttp2 to 1.60.0

dc09b3de054bebe8fb18770f38700230574d4d69

19 files changed, 1712 insertions, 368 deletions

diff --git a/contrib/libs/nghttp2/AUTHORS b/contrib/libs/nghttp2/AUTHORS
index c5c5eb5b2f..178db1b96e 100644
--- a/contrib/libs/nghttp2/AUTHORS
+++ b/contrib/libs/nghttp2/AUTHORS
@@ -112,6 +112,7 @@ Rudi Heitbaum
 Ryo Ota
 Scott Mitchell
 Sebastiaan Deckers
+Sergey Fedorov
 Shelley Vohr
 Simon Frankenberger
 Simone Basso
diff --git a/contrib/libs/nghttp2/README.rst b/contrib/libs/nghttp2/README.rst
index 2af1bcca5d..69dc1ae543 100644
--- a/contrib/libs/nghttp2/README.rst
+++ b/contrib/libs/nghttp2/README.rst
@@ -48,11 +48,6 @@ The following package is required to build the libnghttp2 library:
 
 * pkg-config >= 0.20
 
-To build and run the unit test programs, the following package is
-required:
-
-* cunit >= 2.1
-
 To build the documentation, you need to install:
 
 * sphinx (http://sphinx-doc.org/)
@@ -100,6 +95,11 @@ To mitigate heap fragmentation in long running server programs
      Alpine Linux currently does not support malloc replacement
      due to musl limitations. See details in issue `#762 <https://github.com/nghttp2/nghttp2/issues/762>`_.
 
+For BoringSSL or aws-lc build, to enable :rfc:`8879` TLS Certificate
+Compression in applications, the following library is required:
+
+* libbrotli-dev >= 1.0.9
+
 To enable mruby support for nghttpx, `mruby
 <https://github.com/mruby/mruby>`_ is required.  We need to build
 mruby with C++ ABI explicitly turned on, and probably need other
@@ -127,7 +127,7 @@ following libraries are required:
   <https://github.com/quictls/openssl/tree/OpenSSL_1_1_1w+quic>`_; or
   LibreSSL (does not support 0RTT); or aws-lc; or
   `BoringSSL <https://boringssl.googlesource.com/boringssl/>`_ (commit
-  f42be90d665b6a376177648ccbb76fbbd6497c13)
+  8e6a26d128484b886e6dcbfa558b993d38950bb5)
 * `ngtcp2 <https://github.com/ngtcp2/ngtcp2>`_ >= 1.0.0
 * `nghttp3 <https://github.com/ngtcp2/nghttp3>`_ >= 1.1.0
 
@@ -205,7 +205,7 @@ required packages:
 
     sudo apt-get install g++ clang make binutils autoconf automake \
       autotools-dev libtool pkg-config \
-      zlib1g-dev libcunit1-dev libssl-dev libxml2-dev libev-dev \
+      zlib1g-dev libssl-dev libxml2-dev libev-dev \
       libevent-dev libjansson-dev \
       libc-ares-dev libjemalloc-dev libsystemd-dev \
       ruby-dev bison libelf-dev
@@ -337,23 +337,24 @@ connections alive during reload.
 
 The detailed steps to build HTTP/3 enabled h2load and nghttpx follow.
 
-Build custom OpenSSL:
+Build aws-lc:
 
 .. code-block:: text
 
-   $ git clone --depth 1 -b OpenSSL_1_1_1w+quic https://github.com/quictls/openssl
-   $ cd openssl
-   $ ./config --prefix=$PWD/build --openssldir=/etc/ssl
-   $ make -j$(nproc)
-   $ make install_sw
+   $ git clone --depth 1 -b v1.21.0 https://github.com/aws/aws-lc
+   $ cd aws-lc
+   $ cmake -B build -DDISABLE_GO=ON --install-prefix=$PWD/opt
+   $ make -j$(nproc) -C build
+   $ cmake --install build
    $ cd ..
 
 Build nghttp3:
 
 .. code-block:: text
 
-   $ git clone --depth 1 -b v1.1.0 https://github.com/ngtcp2/nghttp3
+   $ git clone --depth 1 -b v1.2.0 https://github.com/ngtcp2/nghttp3
    $ cd nghttp3
+   $ git submodule update --init --depth 1
    $ autoreconf -i
    $ ./configure --prefix=$PWD/build --enable-lib-only
    $ make -j$(nproc)
@@ -364,11 +365,13 @@ Build ngtcp2:
 
 .. code-block:: text
 
-   $ git clone --depth 1 -b v1.2.0 https://github.com/ngtcp2/ngtcp2
+   $ git clone --depth 1 -b v1.3.0 https://github.com/ngtcp2/ngtcp2
    $ cd ngtcp2
+   $ git submodule update --init --depth 1
    $ autoreconf -i
-   $ ./configure --prefix=$PWD/build --enable-lib-only \
-         PKG_CONFIG_PATH="$PWD/../openssl/build/lib/pkgconfig"
+   $ ./configure --prefix=$PWD/build --enable-lib-only --with-boringssl \
+         BORINGSSL_CFLAGS="-I$PWD/../aws-lc/opt/include" \
+         BORINGSSL_LIBS="-L$PWD/../aws-lc/opt/lib -lssl -lcrypto"
    $ make -j$(nproc)
    $ make install
    $ cd ..
@@ -391,10 +394,10 @@ Build nghttp2:
    $ cd nghttp2
    $ git submodule update --init
    $ autoreconf -i
-   $ ./configure --with-mruby --with-neverbleed --enable-http3 --with-libbpf \
-         CC=clang-14 CXX=clang++-14 \
-         PKG_CONFIG_PATH="$PWD/../openssl/build/lib/pkgconfig:$PWD/../nghttp3/build/lib/pkgconfig:$PWD/../ngtcp2/build/lib/pkgconfig:$PWD/../libbpf/build/lib64/pkgconfig" \
-         LDFLAGS="$LDFLAGS -Wl,-rpath,$PWD/../openssl/build/lib -Wl,-rpath,$PWD/../libbpf/build/lib64"
+   $ ./configure --with-mruby --enable-http3 --with-libbpf \
+         CC=clang-15 CXX=clang++-15 \
+         PKG_CONFIG_PATH="$PWD/../aws-lc/opt/lib/pkgconfig:$PWD/../nghttp3/build/lib/pkgconfig:$PWD/../ngtcp2/build/lib/pkgconfig:$PWD/../libbpf/build/lib64/pkgconfig" \
+         LDFLAGS="$LDFLAGS -Wl,-rpath,$PWD/../aws-lc/opt/lib -Wl,-rpath,$PWD/../libbpf/build/lib64"
    $ make -j$(nproc)
 
 The eBPF program ``reuseport_kern.o`` should be found under bpf
@@ -479,7 +482,7 @@ Previously nghttp2 library did not send client magic, which is first
 24 bytes byte string of client connection preface, and client
 applications have to send it by themselves.  Since v1.0.0, client
 magic is sent by library via first call of ``nghttp2_session_send()``
-or ``nghttp2_session_mem_send()``.
+or ``nghttp2_session_mem_send2()``.
 
 The client applications which send client magic must remove the
 relevant code.
@@ -1446,17 +1449,6 @@ See `Contribution Guidelines
 <https://nghttp2.org/documentation/contribute.html>`_ for more
 details.
 
-Reporting vulnerability
------------------------
-
-If you find a vulnerability in our software, please send the email to
-"tatsuhiro.t at gmail dot com" about its details instead of submitting
-issues on github issue page.  It is a standard practice not to
-disclose vulnerability information publicly until a fixed version is
-released, or mitigation is worked out.
-
-In the future, we may setup a dedicated mail address for this purpose.
-
 Versioning
 ----------
 
diff --git a/contrib/libs/nghttp2/SECURITY.md b/contrib/libs/nghttp2/SECURITY.md
new file mode 100644
index 0000000000..b8328a5ec9
--- /dev/null
+++ b/contrib/libs/nghttp2/SECURITY.md
@@ -0,0 +1,31 @@
+# Security Process
+
+If you find a vulnerability in our software, please report it via
+GitHub "Private vulnerability reporting" feature at
+https://github.com/nghttp2/nghttp2/security instead of submitting
+issues on github issue page.  It is a standard practice not to
+disclose vulnerability information publicly until a fixed version is
+released, or mitigation is worked out.
+
+If we identify that the reported issue is really a vulnerability, we
+open a new security advisory draft using [GitHub security
+feature](https://github.com/nghttp2/nghttp2/security) and discuss the
+mitigation and bug fixes there.  The fixes are committed to the
+private repository.
+
+We write the security advisory and get CVE number from GitHub
+privately.  We also discuss the disclosure date to the public.
+
+We make a new release with the fix at the same time when the
+vulnerability is disclosed to public.
+
+At least 7 days before the public disclosure date, we open a new issue
+on [nghttp2 issue tracker](https://github.com/nghttp2/nghttp2/issues)
+which notifies that the upcoming release will have a security fix.
+The `SECURITY` label is attached to this kind of issue.  The issue is
+not opened if a vulnerability is already disclosed, and it is publicly
+known that nghttp2 is affected by that.
+
+Before few hours of new release, we merge the fixes to the master
+branch (and/or a release branch if necessary) and make a new release.
+Security advisory is disclosed on GitHub.
diff --git a/contrib/libs/nghttp2/config-linux.h b/contrib/libs/nghttp2/config-linux.h
index 82bd630a37..ab5107873e 100644
--- a/contrib/libs/nghttp2/config-linux.h
+++ b/contrib/libs/nghttp2/config-linux.h
@@ -73,6 +73,9 @@
 /* Define to 1 if you have `libbpf` library. */
 /* #undef HAVE_LIBBPF */
 
+/* Define to 1 if you have `libbrotlienc` and `libbrotlidec` libraries. */
+/* #undef HAVE_LIBBROTLI */
+
 /* Define to 1 if you have `libev` library. */
 #define HAVE_LIBEV 1
 
@@ -260,7 +263,7 @@
 #define PACKAGE_NAME "nghttp2"
 
 /* Define to the full name and version of this package. */
-#define PACKAGE_STRING "nghttp2 1.59.0"
+#define PACKAGE_STRING "nghttp2 1.60.0"
 
 /* Define to the one symbol short name of this package. */
 #define PACKAGE_TARNAME "nghttp2"
@@ -269,7 +272,7 @@
 #define PACKAGE_URL ""
 
 /* Define to the version of this package. */
-#define PACKAGE_VERSION "1.59.0"
+#define PACKAGE_VERSION "1.60.0"
 
 /* Define to 1 if all of the C90 standard headers exist (not just the ones
    required in a freestanding environment). This macro is provided for
@@ -368,7 +371,7 @@
 
 
 /* Version number of package */
-#define VERSION "1.59.0"
+#define VERSION "1.60.0"
 
 /* Define WORDS_BIGENDIAN to 1 if your processor stores words with the most
    significant byte first (like Motorola and SPARC, unlike Intel). */
diff --git a/contrib/libs/nghttp2/lib/includes/nghttp2/nghttp2.h b/contrib/libs/nghttp2/lib/includes/nghttp2/nghttp2.h
index 4cc08459a5..582476ff23 100644
--- a/contrib/libs/nghttp2/lib/includes/nghttp2/nghttp2.h
+++ b/contrib/libs/nghttp2/lib/includes/nghttp2/nghttp2.h
@@ -51,6 +51,7 @@ extern "C" {
 #endif /* !defined(_MSC_VER) || (_MSC_VER >= 1800) */
 #include <sys/types.h>
 #include <stdarg.h>
+#include <stddef.h>
 
 #include <nghttp2/nghttp2ver.h>
 
@@ -76,6 +77,13 @@ typedef int ssize_t;
 #endif   /* !defined(WIN32) */
 
 /**
+ * @typedef
+ *
+ * :type:`nghttp2_ssize` is a signed counterpart of size_t.
+ */
+typedef ptrdiff_t nghttp2_ssize;
+
+/**
  * @macro
  *
  * The protocol version identification string of this library
@@ -172,6 +180,12 @@ typedef struct {
 /**
  * @macro
  *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.
+ *
  * The default weight of stream dependency.
  */
 #define NGHTTP2_DEFAULT_WEIGHT 16
@@ -179,6 +193,12 @@ typedef struct {
 /**
  * @macro
  *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.
+ *
  * The maximum weight of stream dependency.
  */
 #define NGHTTP2_MAX_WEIGHT 256
@@ -186,6 +206,12 @@ typedef struct {
 /**
  * @macro
  *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.
+ *
  * The minimum weight of stream dependency.
  */
 #define NGHTTP2_MIN_WEIGHT 1
@@ -259,7 +285,7 @@ typedef enum {
    */
   NGHTTP2_ERR_UNSUPPORTED_VERSION = -503,
   /**
-   * Used as a return value from :type:`nghttp2_send_callback`,
+   * Used as a return value from :type:`nghttp2_send_callback2`,
    * :type:`nghttp2_recv_callback` and
    * :type:`nghttp2_send_data_callback` to indicate that the operation
    * would block.
@@ -279,9 +305,9 @@ typedef enum {
   NGHTTP2_ERR_EOF = -507,
   /**
    * Used as a return value from
-   * :func:`nghttp2_data_source_read_callback` to indicate that data
+   * :func:`nghttp2_data_source_read_callback2` to indicate that data
    * transfer is postponed.  See
-   * :func:`nghttp2_data_source_read_callback` for details.
+   * :func:`nghttp2_data_source_read_callback2` for details.
    */
   NGHTTP2_ERR_DEFERRED = -508,
   /**
@@ -834,7 +860,7 @@ typedef struct {
  * @union
  *
  * This union represents the some kind of data source passed to
- * :type:`nghttp2_data_source_read_callback`.
+ * :type:`nghttp2_data_source_read_callback2`.
  */
 typedef union {
   /**
@@ -851,7 +877,7 @@ typedef union {
  * @enum
  *
  * The flags used to set in |data_flags| output parameter in
- * :type:`nghttp2_data_source_read_callback`.
+ * :type:`nghttp2_data_source_read_callback2`.
  */
 typedef enum {
   /**
@@ -865,8 +891,8 @@ typedef enum {
   /**
    * Indicates that END_STREAM flag must not be set even if
    * NGHTTP2_DATA_FLAG_EOF is set.  Usually this flag is used to send
-   * trailer fields with `nghttp2_submit_request()` or
-   * `nghttp2_submit_response()`.
+   * trailer fields with `nghttp2_submit_request2()` or
+   * `nghttp2_submit_response2()`.
    */
   NGHTTP2_DATA_FLAG_NO_END_STREAM = 0x02,
   /**
@@ -876,9 +902,15 @@ typedef enum {
   NGHTTP2_DATA_FLAG_NO_COPY = 0x04
 } nghttp2_data_flag;
 
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @functypedef
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use :type:`nghttp2_data_source_read_callback2`
+ *   instead.
+ *
  * Callback function invoked when the library wants to read data from
  * the |source|.  The read data is sent in the stream |stream_id|.
  * The implementation of this function must read at most |length|
@@ -943,9 +975,83 @@ typedef ssize_t (*nghttp2_data_source_read_callback)(
     nghttp2_session *session, int32_t stream_id, uint8_t *buf, size_t length,
     uint32_t *data_flags, nghttp2_data_source *source, void *user_data);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @functypedef
+ *
+ * Callback function invoked when the library wants to read data from
+ * the |source|.  The read data is sent in the stream |stream_id|.
+ * The implementation of this function must read at most |length|
+ * bytes of data from |source| (or possibly other places) and store
+ * them in |buf| and return number of data stored in |buf|.  If EOF is
+ * reached, set :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_EOF` flag
+ * in |*data_flags|.
+ *
+ * Sometime it is desirable to avoid copying data into |buf| and let
+ * application to send data directly.  To achieve this, set
+ * :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_NO_COPY` to
+ * |*data_flags| (and possibly other flags, just like when we do
+ * copy), and return the number of bytes to send without copying data
+ * into |buf|.  The library, seeing
+ * :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_NO_COPY`, will invoke
+ * :type:`nghttp2_send_data_callback`.  The application must send
+ * complete DATA frame in that callback.
+ *
+ * If this callback is set by `nghttp2_submit_request2()`,
+ * `nghttp2_submit_response2()` or `nghttp2_submit_headers()` and
+ * `nghttp2_submit_data2()` with flag parameter
+ * :enum:`nghttp2_flag.NGHTTP2_FLAG_END_STREAM` set, and
+ * :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_EOF` flag is set to
+ * |*data_flags|, DATA frame will have END_STREAM flag set.  Usually,
+ * this is expected behaviour and all are fine.  One exception is send
+ * trailer fields.  You cannot send trailer fields after sending frame
+ * with END_STREAM set.  To avoid this problem, one can set
+ * :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_NO_END_STREAM` along
+ * with :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_EOF` to signal the
+ * library not to set END_STREAM in DATA frame.  Then application can
+ * use `nghttp2_submit_trailer()` to send trailer fields.
+ * `nghttp2_submit_trailer()` can be called inside this callback.
+ *
+ * If the application wants to postpone DATA frames (e.g.,
+ * asynchronous I/O, or reading data blocks for long time), it is
+ * achieved by returning :enum:`nghttp2_error.NGHTTP2_ERR_DEFERRED`
+ * without reading any data in this invocation.  The library removes
+ * DATA frame from the outgoing queue temporarily.  To move back
+ * deferred DATA frame to outgoing queue, call
+ * `nghttp2_session_resume_data()`.
+ *
+ * By default, |length| is limited to 16KiB at maximum.  If peer
+ * allows larger frames, application can enlarge transmission buffer
+ * size.  See :type:`nghttp2_data_source_read_length_callback` for
+ * more details.
+ *
+ * If the application just wants to return from
+ * `nghttp2_session_send()` or `nghttp2_session_mem_send2()` without
+ * sending anything, return :enum:`nghttp2_error.NGHTTP2_ERR_PAUSE`.
+ *
+ * In case of error, there are 2 choices. Returning
+ * :enum:`nghttp2_error.NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE` will
+ * close the stream by issuing RST_STREAM with
+ * :enum:`nghttp2_error_code.NGHTTP2_INTERNAL_ERROR`.  If a different
+ * error code is desirable, use `nghttp2_submit_rst_stream()` with a
+ * desired error code and then return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE`.
+ * Returning :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE` will
+ * signal the entire session failure.
+ */
+typedef nghttp2_ssize (*nghttp2_data_source_read_callback2)(
+    nghttp2_session *session, int32_t stream_id, uint8_t *buf, size_t length,
+    uint32_t *data_flags, nghttp2_data_source *source, void *user_data);
+
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @struct
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use :type:`nghttp2_data_provider2` instead.
+ *
  * This struct represents the data source and the way to read a chunk
  * of data from it.
  */
@@ -960,6 +1066,25 @@ typedef struct {
   nghttp2_data_source_read_callback read_callback;
 } nghttp2_data_provider;
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @struct
+ *
+ * This struct represents the data source and the way to read a chunk
+ * of data from it.
+ */
+typedef struct {
+  /**
+   * The data source.
+   */
+  nghttp2_data_source source;
+  /**
+   * The callback function to read a chunk of data from the |source|.
+   */
+  nghttp2_data_source_read_callback2 read_callback;
+} nghttp2_data_provider2;
+
 /**
  * @struct
  *
@@ -1012,6 +1137,12 @@ typedef enum {
 /**
  * @struct
  *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.
+ *
  * The structure to specify stream dependency.
  */
 typedef struct {
@@ -1046,6 +1177,12 @@ typedef struct {
    */
   size_t padlen;
   /**
+   * .. warning::
+   *
+   *   Deprecated.  :rfc:`7540` priorities are deprecated by
+   *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+   *   prioritization scheme.
+   *
    * The priority specification
    */
   nghttp2_priority_spec pri_spec;
@@ -1066,6 +1203,12 @@ typedef struct {
 /**
  * @struct
  *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.
+ *
  * The PRIORITY frame.  It has the following members:
  */
 typedef struct {
@@ -1309,9 +1452,14 @@ typedef union {
   nghttp2_extension ext;
 } nghttp2_frame;
 
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @functypedef
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use :type:`nghttp2_send_callback2` instead.
+ *
  * Callback function invoked when |session| wants to send data to the
  * remote peer.  The implementation of this function must send at most
  * |length| bytes of data stored in |data|.  The |flags| is currently
@@ -1344,6 +1492,44 @@ typedef ssize_t (*nghttp2_send_callback)(nghttp2_session *session,
                                          const uint8_t *data, size_t length,
                                          int flags, void *user_data);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @functypedef
+ *
+ * Callback function invoked when |session| wants to send data to the
+ * remote peer.  The implementation of this function must send at most
+ * |length| bytes of data stored in |data|.  The |flags| is currently
+ * not used and always 0. It must return the number of bytes sent if
+ * it succeeds.  If it cannot send any single byte without blocking,
+ * it must return :enum:`nghttp2_error.NGHTTP2_ERR_WOULDBLOCK`.  For
+ * other errors, it must return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  The
+ * |user_data| pointer is the third argument passed in to the call to
+ * `nghttp2_session_client_new()` or `nghttp2_session_server_new()`.
+ *
+ * This callback is required if the application uses
+ * `nghttp2_session_send()` to send data to the remote endpoint.  If
+ * the application uses solely `nghttp2_session_mem_send2()` instead,
+ * this callback function is unnecessary.
+ *
+ * To set this callback to :type:`nghttp2_session_callbacks`, use
+ * `nghttp2_session_callbacks_set_send_callback2()`.
+ *
+ * .. note::
+ *
+ *   The |length| may be very small.  If that is the case, and
+ *   application disables Nagle algorithm (``TCP_NODELAY``), then just
+ *   writing |data| to the network stack leads to very small packet,
+ *   and it is very inefficient.  An application should be responsible
+ *   to buffer up small chunks of data as necessary to avoid this
+ *   situation.
+ */
+typedef nghttp2_ssize (*nghttp2_send_callback2)(nghttp2_session *session,
+                                                const uint8_t *data,
+                                                size_t length, int flags,
+                                                void *user_data);
+
 /**
  * @functypedef
  *
@@ -1374,7 +1560,7 @@ typedef ssize_t (*nghttp2_send_callback)(nghttp2_session *session,
  * error; if partial frame data has already sent, it is impossible to
  * send another data in that state, and all we can do is tear down
  * connection).  When data is fully processed, but application wants
- * to make `nghttp2_session_mem_send()` or `nghttp2_session_send()`
+ * to make `nghttp2_session_mem_send2()` or `nghttp2_session_send()`
  * return immediately without processing next frames, return
  * :enum:`nghttp2_error.NGHTTP2_ERR_PAUSE`.  If application decided to
  * reset this stream, return
@@ -1391,9 +1577,14 @@ typedef int (*nghttp2_send_data_callback)(nghttp2_session *session,
                                           nghttp2_data_source *source,
                                           void *user_data);
 
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @functypedef
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use :type:`nghttp2_recv_callback2` instead.
+ *
  * Callback function invoked when |session| wants to receive data from
  * the remote peer.  The implementation of this function must read at
  * most |length| bytes of data and store it in |buf|.  The |flags| is
@@ -1421,11 +1612,43 @@ typedef ssize_t (*nghttp2_recv_callback)(nghttp2_session *session, uint8_t *buf,
                                          size_t length, int flags,
                                          void *user_data);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @functypedef
+ *
+ * Callback function invoked when |session| wants to receive data from
+ * the remote peer.  The implementation of this function must read at
+ * most |length| bytes of data and store it in |buf|.  The |flags| is
+ * currently not used and always 0.  It must return the number of
+ * bytes written in |buf| if it succeeds.  If it cannot read any
+ * single byte without blocking, it must return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_WOULDBLOCK`.  If it gets EOF
+ * before it reads any single byte, it must return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_EOF`.  For other errors, it must
+ * return :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
+ * Returning 0 is treated as
+ * :enum:`nghttp2_error.NGHTTP2_ERR_WOULDBLOCK`.  The |user_data|
+ * pointer is the third argument passed in to the call to
+ * `nghttp2_session_client_new()` or `nghttp2_session_server_new()`.
+ *
+ * This callback is required if the application uses
+ * `nghttp2_session_recv()` to receive data from the remote endpoint.
+ * If the application uses solely `nghttp2_session_mem_recv2()`
+ * instead, this callback function is unnecessary.
+ *
+ * To set this callback to :type:`nghttp2_session_callbacks`, use
+ * `nghttp2_session_callbacks_set_recv_callback2()`.
+ */
+typedef nghttp2_ssize (*nghttp2_recv_callback2)(nghttp2_session *session,
+                                                uint8_t *buf, size_t length,
+                                                int flags, void *user_data);
+
 /**
  * @functypedef
  *
  * Callback function invoked by `nghttp2_session_recv()` and
- * `nghttp2_session_mem_recv()` when a frame is received.  The
+ * `nghttp2_session_mem_recv2()` when a frame is received.  The
  * |user_data| pointer is the third argument passed in to the call to
  * `nghttp2_session_client_new()` or `nghttp2_session_server_new()`.
  *
@@ -1443,8 +1666,8 @@ typedef ssize_t (*nghttp2_recv_callback)(nghttp2_session *session, uint8_t *buf,
  *
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero value is returned, it is treated as fatal error and
- * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
- * immediately return
+ * `nghttp2_session_recv()` and `nghttp2_session_mem_recv2()`
+ * functions immediately return
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
@@ -1458,7 +1681,7 @@ typedef int (*nghttp2_on_frame_recv_callback)(nghttp2_session *session,
  * @functypedef
  *
  * Callback function invoked by `nghttp2_session_recv()` and
- * `nghttp2_session_mem_recv()` when an invalid non-DATA frame is
+ * `nghttp2_session_mem_recv2()` when an invalid non-DATA frame is
  * received.  The error is indicated by the |lib_error_code|, which is
  * one of the values defined in :type:`nghttp2_error`.  When this
  * callback function is invoked, the library automatically submits
@@ -1472,8 +1695,8 @@ typedef int (*nghttp2_on_frame_recv_callback)(nghttp2_session *session,
  *
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero is returned, it is treated as fatal error and
- * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
- * immediately return
+ * `nghttp2_session_recv()` and `nghttp2_session_mem_recv2()`
+ * functions immediately return
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
@@ -1496,19 +1719,19 @@ typedef int (*nghttp2_on_invalid_frame_recv_callback)(
  * argument passed in to the call to `nghttp2_session_client_new()` or
  * `nghttp2_session_server_new()`.
  *
- * If the application uses `nghttp2_session_mem_recv()`, it can return
- * :enum:`nghttp2_error.NGHTTP2_ERR_PAUSE` to make
- * `nghttp2_session_mem_recv()` return without processing further
+ * If the application uses `nghttp2_session_mem_recv2()`, it can
+ * return :enum:`nghttp2_error.NGHTTP2_ERR_PAUSE` to make
+ * `nghttp2_session_mem_recv2()` return without processing further
  * input bytes.  The memory by pointed by the |data| is retained until
- * `nghttp2_session_mem_recv()` or `nghttp2_session_recv()` is called.
- * The application must retain the input bytes which was used to
- * produce the |data| parameter, because it may refer to the memory
+ * `nghttp2_session_mem_recv2()` or `nghttp2_session_recv()` is
+ * called.  The application must retain the input bytes which was used
+ * to produce the |data| parameter, because it may refer to the memory
  * region included in the input bytes.
  *
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero is returned, it is treated as fatal error, and
- * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
- * immediately return
+ * `nghttp2_session_recv()` and `nghttp2_session_mem_recv2()`
+ * functions immediately return
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
@@ -1535,8 +1758,8 @@ typedef int (*nghttp2_on_data_chunk_recv_callback)(nghttp2_session *session,
  * If there is a fatal error while executing this callback, the
  * implementation should return
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`, which makes
- * `nghttp2_session_send()` and `nghttp2_session_mem_send()` functions
- * immediately return
+ * `nghttp2_session_send()` and `nghttp2_session_mem_send2()`
+ * functions immediately return
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * If the other value is returned, it is treated as if
@@ -1560,8 +1783,8 @@ typedef int (*nghttp2_before_frame_send_callback)(nghttp2_session *session,
  *
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero is returned, it is treated as fatal error and
- * `nghttp2_session_send()` and `nghttp2_session_mem_send()` functions
- * immediately return
+ * `nghttp2_session_send()` and `nghttp2_session_mem_send2()`
+ * functions immediately return
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
@@ -1583,8 +1806,8 @@ typedef int (*nghttp2_on_frame_send_callback)(nghttp2_session *session,
  *
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero is returned, it is treated as fatal error and
- * `nghttp2_session_send()` and `nghttp2_session_mem_send()` functions
- * immediately return
+ * `nghttp2_session_send()` and `nghttp2_session_mem_send2()`
+ * functions immediately return
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * `nghttp2_session_get_stream_user_data()` can be used to get
@@ -1605,7 +1828,7 @@ typedef int (*nghttp2_on_frame_not_send_callback)(nghttp2_session *session,
  * The reason of closure is indicated by the |error_code|.  The
  * |error_code| is usually one of :enum:`nghttp2_error_code`, but that
  * is not guaranteed.  The stream_user_data, which was specified in
- * `nghttp2_submit_request()` or `nghttp2_submit_headers()`, is still
+ * `nghttp2_submit_request2()` or `nghttp2_submit_headers()`, is still
  * available in this function.  The |user_data| pointer is the third
  * argument passed in to the call to `nghttp2_session_client_new()` or
  * `nghttp2_session_server_new()`.
@@ -1614,8 +1837,8 @@ typedef int (*nghttp2_on_frame_not_send_callback)(nghttp2_session *session,
  *
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero is returned, it is treated as fatal error and
- * `nghttp2_session_recv()`, `nghttp2_session_mem_recv()`,
- * `nghttp2_session_send()`, and `nghttp2_session_mem_send()`
+ * `nghttp2_session_recv()`, `nghttp2_session_mem_recv2()`,
+ * `nghttp2_session_send()`, and `nghttp2_session_mem_send2()`
  * functions immediately return
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
@@ -1685,7 +1908,7 @@ typedef int (*nghttp2_on_stream_close_callback)(nghttp2_session *session,
  * value is returned, it is treated as if
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE` is returned.  If
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE` is returned,
- * `nghttp2_session_mem_recv()` function will immediately return
+ * `nghttp2_session_mem_recv2()` function will immediately return
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
@@ -1730,11 +1953,11 @@ typedef int (*nghttp2_on_begin_headers_callback)(nghttp2_session *session,
  * performs validation based on HTTP Messaging rule, which is briefly
  * explained in :ref:`http-messaging` section.
  *
- * If the application uses `nghttp2_session_mem_recv()`, it can return
- * :enum:`nghttp2_error.NGHTTP2_ERR_PAUSE` to make
- * `nghttp2_session_mem_recv()` return without processing further
+ * If the application uses `nghttp2_session_mem_recv2()`, it can
+ * return :enum:`nghttp2_error.NGHTTP2_ERR_PAUSE` to make
+ * `nghttp2_session_mem_recv2()` return without processing further
  * input bytes.  The memory pointed by |frame|, |name| and |value|
- * parameters are retained until `nghttp2_session_mem_recv()` or
+ * parameters are retained until `nghttp2_session_mem_recv2()` or
  * `nghttp2_session_recv()` is called.  The application must retain
  * the input bytes which was used to produce these parameters, because
  * it may refer to the memory region included in the input bytes.
@@ -1761,8 +1984,8 @@ typedef int (*nghttp2_on_begin_headers_callback)(nghttp2_session *session,
  * nonzero value is returned, it is treated as
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  If
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE` is returned,
- * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
- * immediately return
+ * `nghttp2_session_recv()` and `nghttp2_session_mem_recv2()`
+ * functions immediately return
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
@@ -1877,9 +2100,15 @@ typedef int (*nghttp2_on_invalid_header_callback2)(
     nghttp2_session *session, const nghttp2_frame *frame, nghttp2_rcbuf *name,
     nghttp2_rcbuf *value, uint8_t flags, void *user_data);
 
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @functypedef
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use :type:`nghttp2_select_padding_callback2`
+ *   instead.
+ *
  * Callback function invoked when the library asks application how
  * many padding bytes are required for the transmission of the
  * |frame|.  The application must choose the total length of payload
@@ -1900,9 +2129,39 @@ typedef ssize_t (*nghttp2_select_padding_callback)(nghttp2_session *session,
                                                    size_t max_payloadlen,
                                                    void *user_data);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @functypedef
+ *
+ * Callback function invoked when the library asks application how
+ * many padding bytes are required for the transmission of the
+ * |frame|.  The application must choose the total length of payload
+ * including padded bytes in range [frame->hd.length, max_payloadlen],
+ * inclusive.  Choosing number not in this range will be treated as
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  Returning
+ * ``frame->hd.length`` means no padding is added.  Returning
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE` will make
+ * `nghttp2_session_send()` and `nghttp2_session_mem_send2()`
+ * functions immediately return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
+ *
+ * To set this callback to :type:`nghttp2_session_callbacks`, use
+ * `nghttp2_session_callbacks_set_select_padding_callback2()`.
+ */
+typedef nghttp2_ssize (*nghttp2_select_padding_callback2)(
+    nghttp2_session *session, const nghttp2_frame *frame, size_t max_payloadlen,
+    void *user_data);
+
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @functypedef
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use
+ *   :type:`nghttp2_data_source_read_length_callback2` instead.
+ *
  * Callback function invoked when library wants to get max length of
  * data to send data to the remote peer.  The implementation of this
  * function should return a value in the following range.  [1,
@@ -1930,6 +2189,38 @@ typedef ssize_t (*nghttp2_data_source_read_length_callback)(
     int32_t session_remote_window_size, int32_t stream_remote_window_size,
     uint32_t remote_max_frame_size, void *user_data);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @functypedef
+ *
+ * Callback function invoked when library wants to get max length of
+ * data to send data to the remote peer.  The implementation of this
+ * function should return a value in the following range.  [1,
+ * min(|session_remote_window_size|, |stream_remote_window_size|,
+ * |remote_max_frame_size|)].  If a value greater than this range is
+ * returned than the max allow value will be used.  Returning a value
+ * smaller than this range is treated as
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  The
+ * |frame_type| is provided for future extensibility and identifies
+ * the type of frame (see :type:`nghttp2_frame_type`) for which to get
+ * the length for.  Currently supported frame types are:
+ * :enum:`nghttp2_frame_type.NGHTTP2_DATA`.
+ *
+ * This callback can be used to control the length in bytes for which
+ * :type:`nghttp2_data_source_read_callback` is allowed to send to the
+ * remote endpoint.  This callback is optional.  Returning
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE` will signal the
+ * entire session failure.
+ *
+ * To set this callback to :type:`nghttp2_session_callbacks`, use
+ * `nghttp2_session_callbacks_set_data_source_read_length_callback2()`.
+ */
+typedef nghttp2_ssize (*nghttp2_data_source_read_length_callback2)(
+    nghttp2_session *session, uint8_t frame_type, int32_t stream_id,
+    int32_t session_remote_window_size, int32_t stream_remote_window_size,
+    uint32_t remote_max_frame_size, void *user_data);
+
 /**
  * @functypedef
  *
@@ -1946,8 +2237,8 @@ typedef ssize_t (*nghttp2_data_source_read_length_callback)(
  *
  * The implementation of this function must return 0 if it succeeds.
  * If nonzero value is returned, it is treated as fatal error and
- * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
- * immediately return
+ * `nghttp2_session_recv()` and `nghttp2_session_mem_recv2()`
+ * functions immediately return
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
  *
  * To set this callback to :type:`nghttp2_session_callbacks`, use
@@ -1971,8 +2262,8 @@ typedef int (*nghttp2_on_begin_frame_callback)(nghttp2_session *session,
  *
  * If fatal error occurred, application should return
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  In this case,
- * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
- * immediately return
+ * `nghttp2_session_recv()` and `nghttp2_session_mem_recv2()`
+ * functions immediately return
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  If the other
  * values are returned, currently they are treated as
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
@@ -2009,8 +2300,8 @@ typedef int (*nghttp2_on_extension_chunk_recv_callback)(
  *
  * If fatal error occurred, application should return
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  In this case,
- * `nghttp2_session_recv()` and `nghttp2_session_mem_recv()` functions
- * immediately return
+ * `nghttp2_session_recv()` and `nghttp2_session_mem_recv2()`
+ * functions immediately return
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  If the other
  * values are returned, currently they are treated as
  * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
@@ -2020,9 +2311,15 @@ typedef int (*nghttp2_unpack_extension_callback)(nghttp2_session *session,
                                                  const nghttp2_frame_hd *hd,
                                                  void *user_data);
 
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @functypedef
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use :type:`nghttp2_pack_extension_callback2`
+ *   instead.
+ *
  * Callback function invoked when library asks the application to pack
  * extension payload in its wire format.  The frame header will be
  * packed by library.  Application must pack payload only.
@@ -2053,18 +2350,53 @@ typedef ssize_t (*nghttp2_pack_extension_callback)(nghttp2_session *session,
                                                    const nghttp2_frame *frame,
                                                    void *user_data);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @functypedef
+ *
+ * Callback function invoked when library asks the application to pack
+ * extension payload in its wire format.  The frame header will be
+ * packed by library.  Application must pack payload only.
+ * ``frame->ext.payload`` is the object passed to
+ * `nghttp2_submit_extension()` as payload parameter.  Application
+ * must pack extension payload to the |buf| of its capacity |len|
+ * bytes.  The |len| is at least 16KiB.
+ *
+ * The implementation of this function should return the number of
+ * bytes written into |buf| when it succeeds.
+ *
+ * To abort processing this extension frame, return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CANCEL`, and
+ * :type:`nghttp2_on_frame_not_send_callback` will be invoked.
+ *
+ * If fatal error occurred, application should return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  In this case,
+ * `nghttp2_session_send()` and `nghttp2_session_mem_send2()`
+ * functions immediately return
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  If the other
+ * values are returned, currently they are treated as
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.  If the return
+ * value is strictly larger than |len|, it is treated as
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`.
+ */
+typedef nghttp2_ssize (*nghttp2_pack_extension_callback2)(
+    nghttp2_session *session, uint8_t *buf, size_t len,
+    const nghttp2_frame *frame, void *user_data);
+
 /**
  * @functypedef
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use :type:`nghttp2_error_callback2` instead.
+ *
  * Callback function invoked when library provides the error message
  * intended for human consumption.  This callback is solely for
  * debugging purpose.  The |msg| is typically NULL-terminated string
  * of length |len|.  |len| does not include the sentinel NULL
  * character.
  *
- * This function is deprecated.  The new application should use
- * :type:`nghttp2_error_callback2`.
- *
  * The format of error message may change between nghttp2 library
  * versions.  The application should not depend on the particular
  * format.
@@ -2147,9 +2479,15 @@ nghttp2_session_callbacks_new(nghttp2_session_callbacks **callbacks_ptr);
 NGHTTP2_EXTERN void
 nghttp2_session_callbacks_del(nghttp2_session_callbacks *callbacks);
 
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use `nghttp2_session_callbacks_set_send_callback2()`
+ *   with :type:`nghttp2_send_callback2` instead.
+ *
  * Sets callback function invoked when a session wants to send data to
  * the remote peer.  This callback is not necessary if the application
  * uses solely `nghttp2_session_mem_send()` to serialize data to
@@ -2158,9 +2496,28 @@ nghttp2_session_callbacks_del(nghttp2_session_callbacks *callbacks);
 NGHTTP2_EXTERN void nghttp2_session_callbacks_set_send_callback(
     nghttp2_session_callbacks *cbs, nghttp2_send_callback send_callback);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @function
+ *
+ * Sets callback function invoked when a session wants to send data to
+ * the remote peer.  This callback is not necessary if the application
+ * uses solely `nghttp2_session_mem_send2()` to serialize data to
+ * transmit.
+ */
+NGHTTP2_EXTERN void nghttp2_session_callbacks_set_send_callback2(
+    nghttp2_session_callbacks *cbs, nghttp2_send_callback2 send_callback);
+
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use `nghttp2_session_callbacks_set_recv_callback2()`
+ *   with :type:`nghttp2_recv_callback2` instead.
+ *
  * Sets callback function invoked when the a session wants to receive
  * data from the remote peer.  This callback is not necessary if the
  * application uses solely `nghttp2_session_mem_recv()` to process
@@ -2169,11 +2526,24 @@ NGHTTP2_EXTERN void nghttp2_session_callbacks_set_send_callback(
 NGHTTP2_EXTERN void nghttp2_session_callbacks_set_recv_callback(
     nghttp2_session_callbacks *cbs, nghttp2_recv_callback recv_callback);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @function
+ *
+ * Sets callback function invoked when the a session wants to receive
+ * data from the remote peer.  This callback is not necessary if the
+ * application uses solely `nghttp2_session_mem_recv2()` to process
+ * received data.
+ */
+NGHTTP2_EXTERN void nghttp2_session_callbacks_set_recv_callback2(
+    nghttp2_session_callbacks *cbs, nghttp2_recv_callback2 recv_callback);
+
 /**
  * @function
  *
  * Sets callback function invoked by `nghttp2_session_recv()` and
- * `nghttp2_session_mem_recv()` when a frame is received.
+ * `nghttp2_session_mem_recv2()` when a frame is received.
  */
 NGHTTP2_EXTERN void nghttp2_session_callbacks_set_on_frame_recv_callback(
     nghttp2_session_callbacks *cbs,
@@ -2183,7 +2553,7 @@ NGHTTP2_EXTERN void nghttp2_session_callbacks_set_on_frame_recv_callback(
  * @function
  *
  * Sets callback function invoked by `nghttp2_session_recv()` and
- * `nghttp2_session_mem_recv()` when an invalid non-DATA frame is
+ * `nghttp2_session_mem_recv2()` when an invalid non-DATA frame is
  * received.
  */
 NGHTTP2_EXTERN void
@@ -2294,9 +2664,16 @@ NGHTTP2_EXTERN void nghttp2_session_callbacks_set_on_invalid_header_callback2(
     nghttp2_session_callbacks *cbs,
     nghttp2_on_invalid_header_callback2 on_invalid_header_callback2);
 
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use
+ *   `nghttp2_session_callbacks_set_select_padding_callback2()` with
+ *   :type:`nghttp2_select_padding_callback2` instead.
+ *
  * Sets callback function invoked when the library asks application
  * how many padding bytes are required for the transmission of the
  * given frame.
@@ -2305,9 +2682,29 @@ NGHTTP2_EXTERN void nghttp2_session_callbacks_set_select_padding_callback(
     nghttp2_session_callbacks *cbs,
     nghttp2_select_padding_callback select_padding_callback);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
 /**
  * @function
  *
+ * Sets callback function invoked when the library asks application
+ * how many padding bytes are required for the transmission of the
+ * given frame.
+ */
+NGHTTP2_EXTERN void nghttp2_session_callbacks_set_select_padding_callback2(
+    nghttp2_session_callbacks *cbs,
+    nghttp2_select_padding_callback2 select_padding_callback);
+
+#ifndef NGHTTP2_NO_SSIZE_T
+/**
+ * @function
+ *
+ * .. warning::
+ *
+ *   Deprecated.  Use
+ *   `nghttp2_session_callbacks_set_data_source_read_length_callback2()`
+ *   with :type:`nghttp2_data_source_read_length_callback2` instead.
+ *
  * Sets callback function determine the length allowed in
  * :type:`nghttp2_data_source_read_callback`.
  */
@@ -2316,6 +2713,19 @@ nghttp2_session_callbacks_set_data_source_read_length_callback(
     nghttp2_session_callbacks *cbs,
     nghttp2_data_source_read_length_callback data_source_read_length_callback);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @function
+ *
+ * Sets callback function determine the length allowed in
+ * :type:`nghttp2_data_source_read_callback2`.
+ */
+NGHTTP2_EXTERN void
+nghttp2_session_callbacks_set_data_source_read_length_callback2(
+    nghttp2_session_callbacks *cbs,
+    nghttp2_data_source_read_length_callback2 data_source_read_length_callback);
+
 /**
  * @function
  *
@@ -2330,15 +2740,22 @@ NGHTTP2_EXTERN void nghttp2_session_callbacks_set_on_begin_frame_callback(
  *
  * Sets callback function invoked when
  * :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_NO_COPY` is used in
- * :type:`nghttp2_data_source_read_callback` to avoid data copy.
+ * :type:`nghttp2_data_source_read_callback2` to avoid data copy.
  */
 NGHTTP2_EXTERN void nghttp2_session_callbacks_set_send_data_callback(
     nghttp2_session_callbacks *cbs,
     nghttp2_send_data_callback send_data_callback);
 
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use
+ *   `nghttp2_session_callbacks_set_pack_extension_callback2()` with
+ *   :type:`nghttp2_pack_extension_callback2` instead.
+ *
  * Sets callback function invoked when the library asks the
  * application to pack extension frame payload in wire format.
  */
@@ -2346,6 +2763,18 @@ NGHTTP2_EXTERN void nghttp2_session_callbacks_set_pack_extension_callback(
     nghttp2_session_callbacks *cbs,
     nghttp2_pack_extension_callback pack_extension_callback);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @function
+ *
+ * Sets callback function invoked when the library asks the
+ * application to pack extension frame payload in wire format.
+ */
+NGHTTP2_EXTERN void nghttp2_session_callbacks_set_pack_extension_callback2(
+    nghttp2_session_callbacks *cbs,
+    nghttp2_pack_extension_callback2 pack_extension_callback);
+
 /**
  * @function
  *
@@ -2370,12 +2799,15 @@ nghttp2_session_callbacks_set_on_extension_chunk_recv_callback(
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use
+ *   `nghttp2_session_callbacks_set_error_callback2()` with
+ *   :type:`nghttp2_error_callback2` instead.
+ *
  * Sets callback function invoked when library tells error message to
  * the application.
  *
- * This function is deprecated.  The new application should use
- * `nghttp2_session_callbacks_set_error_callback2()`.
- *
  * If both :type:`nghttp2_error_callback` and
  * :type:`nghttp2_error_callback2` are set, the latter takes
  * precedence.
@@ -2572,7 +3004,7 @@ nghttp2_option_set_peer_max_concurrent_streams(nghttp2_option *option,
  *
  * If this option is not used or used with zero value, if MAGIC does
  * not match :macro:`NGHTTP2_CLIENT_MAGIC`, `nghttp2_session_recv()`
- * and `nghttp2_session_mem_recv()` will return error
+ * and `nghttp2_session_mem_recv2()` will return error
  * :enum:`nghttp2_error.NGHTTP2_ERR_BAD_CLIENT_MAGIC`, which is fatal
  * error.
  */
@@ -2785,7 +3217,7 @@ nghttp2_option_set_stream_reset_rate_limit(nghttp2_option *option,
  * does not store |callbacks|.  The |user_data| is an arbitrary user
  * supplied data, which will be passed to the callback functions.
  *
- * The :type:`nghttp2_send_callback` must be specified.  If the
+ * The :type:`nghttp2_send_callback2` must be specified.  If the
  * application code uses `nghttp2_session_recv()`, the
  * :type:`nghttp2_recv_callback` must be specified.  The other members
  * of |callbacks| can be ``NULL``.
@@ -2811,7 +3243,7 @@ nghttp2_session_client_new(nghttp2_session **session_ptr,
  * does not store |callbacks|.  The |user_data| is an arbitrary user
  * supplied data, which will be passed to the callback functions.
  *
- * The :type:`nghttp2_send_callback` must be specified.  If the
+ * The :type:`nghttp2_send_callback2` must be specified.  If the
  * application code uses `nghttp2_session_recv()`, the
  * :type:`nghttp2_recv_callback` must be specified.  The other members
  * of |callbacks| can be ``NULL``.
@@ -2947,7 +3379,7 @@ NGHTTP2_EXTERN void nghttp2_session_del(nghttp2_session *session);
  * This function retrieves the highest prioritized frame from the
  * outbound queue and sends it to the remote peer.  It does this as
  * many times as possible until the user callback
- * :type:`nghttp2_send_callback` returns
+ * :type:`nghttp2_send_callback2` returns
  * :enum:`nghttp2_error.NGHTTP2_ERR_WOULDBLOCK`, the outbound queue
  * becomes empty or flow control is triggered (remote window size
  * becomes depleted or maximum number of concurrent streams is
@@ -2977,7 +3409,7 @@ NGHTTP2_EXTERN void nghttp2_session_del(nghttp2_session *session);
  *    :type:`nghttp2_on_frame_not_send_callback` is invoked.  Abort
  *    the following steps.
  *
- * 8. :type:`nghttp2_send_callback` is invoked one or more times to
+ * 8. :type:`nghttp2_send_callback2` is invoked one or more times to
  *    send the frame.
  *
  * 9. :type:`nghttp2_on_frame_send_callback` is invoked.
@@ -2996,9 +3428,14 @@ NGHTTP2_EXTERN void nghttp2_session_del(nghttp2_session *session);
  */
 NGHTTP2_EXTERN int nghttp2_session_send(nghttp2_session *session);
 
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use `nghttp2_session_mem_send2()` instead.
+ *
  * Returns the serialized data to send.
  *
  * This function behaves like `nghttp2_session_send()` except that it
@@ -3038,6 +3475,50 @@ NGHTTP2_EXTERN int nghttp2_session_send(nghttp2_session *session);
 NGHTTP2_EXTERN ssize_t nghttp2_session_mem_send(nghttp2_session *session,
                                                 const uint8_t **data_ptr);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @function
+ *
+ * Returns the serialized data to send.
+ *
+ * This function behaves like `nghttp2_session_send()` except that it
+ * does not use :type:`nghttp2_send_callback2` to transmit data.
+ * Instead, it assigns the pointer to the serialized data to the
+ * |*data_ptr| and returns its length.  The other callbacks are called
+ * in the same way as they are in `nghttp2_session_send()`.
+ *
+ * If no data is available to send, this function returns 0.
+ *
+ * This function may not return all serialized data in one invocation.
+ * To get all data, call this function repeatedly until it returns 0
+ * or one of negative error codes.
+ *
+ * The assigned |*data_ptr| is valid until the next call of
+ * `nghttp2_session_mem_send2()` or `nghttp2_session_send()`.
+ *
+ * The caller must send all data before sending the next chunk of
+ * data.
+ *
+ * This function returns the length of the data pointed by the
+ * |*data_ptr| if it succeeds, or one of the following negative error
+ * codes:
+ *
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
+ *     Out of memory.
+ *
+ * .. note::
+ *
+ *   This function may produce very small byte string.  If that is the
+ *   case, and application disables Nagle algorithm (``TCP_NODELAY``),
+ *   then writing this small chunk leads to very small packet, and it
+ *   is very inefficient.  An application should be responsible to
+ *   buffer up small chunks of data as necessary to avoid this
+ *   situation.
+ */
+NGHTTP2_EXTERN nghttp2_ssize
+nghttp2_session_mem_send2(nghttp2_session *session, const uint8_t **data_ptr);
+
 /**
  * @function
  *
@@ -3108,9 +3589,14 @@ NGHTTP2_EXTERN ssize_t nghttp2_session_mem_send(nghttp2_session *session,
  */
 NGHTTP2_EXTERN int nghttp2_session_recv(nghttp2_session *session);
 
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use `nghttp2_session_mem_recv2()` instead.
+ *
  * Processes data |in| as an input from the remote endpoint.  The
  * |inlen| indicates the number of bytes to receive in the |in|.
  *
@@ -3149,6 +3635,49 @@ NGHTTP2_EXTERN ssize_t nghttp2_session_mem_recv(nghttp2_session *session,
                                                 const uint8_t *in,
                                                 size_t inlen);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @function
+ *
+ * Processes data |in| as an input from the remote endpoint.  The
+ * |inlen| indicates the number of bytes to receive in the |in|.
+ *
+ * This function behaves like `nghttp2_session_recv()` except that it
+ * does not use :type:`nghttp2_recv_callback` to receive data; the
+ * |in| is the only data for the invocation of this function.  If all
+ * bytes are processed, this function returns.  The other callbacks
+ * are called in the same way as they are in `nghttp2_session_recv()`.
+ *
+ * In the current implementation, this function always tries to
+ * processes |inlen| bytes of input data unless either an error occurs or
+ * :enum:`nghttp2_error.NGHTTP2_ERR_PAUSE` is returned from
+ * :type:`nghttp2_on_header_callback` or
+ * :type:`nghttp2_on_data_chunk_recv_callback`.  If
+ * :enum:`nghttp2_error.NGHTTP2_ERR_PAUSE` is used, the return value
+ * includes the number of bytes which was used to produce the data or
+ * frame for the callback.
+ *
+ * This function returns the number of processed bytes, or one of the
+ * following negative error codes:
+ *
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
+ *     Out of memory.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_CALLBACK_FAILURE`
+ *     The callback function failed.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_BAD_CLIENT_MAGIC`
+ *     Invalid client magic was detected.  This error only returns
+ *     when |session| was configured as server and
+ *     `nghttp2_option_set_no_recv_client_magic()` is not used with
+ *     nonzero value.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_FLOODED`
+ *     Flooding was detected in this HTTP/2 session, and it must be
+ *     closed.  This is most likely caused by misbehaviour of peer.
+ */
+NGHTTP2_EXTERN nghttp2_ssize nghttp2_session_mem_recv2(nghttp2_session *session,
+                                                       const uint8_t *in,
+                                                       size_t inlen);
+
 /**
  * @function
  *
@@ -3194,7 +3723,7 @@ NGHTTP2_EXTERN int nghttp2_session_want_write(nghttp2_session *session);
  * @function
  *
  * Returns stream_user_data for the stream |stream_id|.  The
- * stream_user_data is provided by `nghttp2_submit_request()`,
+ * stream_user_data is provided by `nghttp2_submit_request2()`,
  * `nghttp2_submit_headers()` or
  * `nghttp2_session_set_stream_user_data()`.  Unless it is set using
  * `nghttp2_session_set_stream_user_data()`, if the stream is
@@ -3630,6 +4159,13 @@ NGHTTP2_EXTERN int nghttp2_session_consume_stream(nghttp2_session *session,
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.  In the future release after the end of
+ *   2024, this function will always return 0 without doing anything.
+ *
  * Changes priority of existing stream denoted by |stream_id|.  The
  * new priority specification is |pri_spec|.
  *
@@ -3669,6 +4205,13 @@ nghttp2_session_change_stream_priority(nghttp2_session *session,
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.  In the future release after the end of
+ *   2024, this function will always return 0 without doing anything.
+ *
  * Creates idle stream with the given |stream_id|, and priority
  * |pri_spec|.
  *
@@ -3719,10 +4262,6 @@ nghttp2_session_create_idle_stream(nghttp2_session *session, int32_t stream_id,
 /**
  * @function
  *
- * Performs post-process of HTTP Upgrade request.  This function can
- * be called from both client and server, but the behavior is very
- * different in each other.
- *
  * .. warning::
  *
  *   This function is deprecated in favor of
@@ -3734,6 +4273,10 @@ nghttp2_session_create_idle_stream(nghttp2_session *session, int32_t stream_id,
  *   HEAD is used in request, the length of response body must be 0
  *   regardless of value included in content-length header field.
  *
+ * Performs post-process of HTTP Upgrade request.  This function can
+ * be called from both client and server, but the behavior is very
+ * different in each other.
+ *
  * If called from client side, the |settings_payload| must be the
  * value sent in ``HTTP2-Settings`` header field and must be decoded
  * by base64url decoder.  The |settings_payloadlen| is the length of
@@ -3813,9 +4356,14 @@ NGHTTP2_EXTERN int nghttp2_session_upgrade2(nghttp2_session *session,
                                             int head_request,
                                             void *stream_user_data);
 
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use `nghttp2_pack_settings_payload2()` instead.
+ *
  * Serializes the SETTINGS values |iv| in the |buf|.  The size of the
  * |buf| is specified by |buflen|.  The number of entries in the |iv|
  * array is given by |niv|.  The required space in |buf| for the |niv|
@@ -3837,6 +4385,32 @@ NGHTTP2_EXTERN int nghttp2_session_upgrade2(nghttp2_session *session,
 NGHTTP2_EXTERN ssize_t nghttp2_pack_settings_payload(
     uint8_t *buf, size_t buflen, const nghttp2_settings_entry *iv, size_t niv);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @function
+ *
+ * Serializes the SETTINGS values |iv| in the |buf|.  The size of the
+ * |buf| is specified by |buflen|.  The number of entries in the |iv|
+ * array is given by |niv|.  The required space in |buf| for the |niv|
+ * entries is ``6*niv`` bytes and if the given buffer is too small, an
+ * error is returned.  This function is used mainly for creating a
+ * SETTINGS payload to be sent with the ``HTTP2-Settings`` header
+ * field in an HTTP Upgrade request.  The data written in |buf| is NOT
+ * base64url encoded and the application is responsible for encoding.
+ *
+ * This function returns the number of bytes written in |buf|, or one
+ * of the following negative error codes:
+ *
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
+ *     The |iv| contains duplicate settings ID or invalid value.
+ *
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INSUFF_BUFSIZE`
+ *     The provided |buflen| size is too small to hold the output.
+ */
+NGHTTP2_EXTERN nghttp2_ssize nghttp2_pack_settings_payload2(
+    uint8_t *buf, size_t buflen, const nghttp2_settings_entry *iv, size_t niv);
+
 /**
  * @function
  *
@@ -3858,6 +4432,12 @@ NGHTTP2_EXTERN const char *nghttp2_http2_strerror(uint32_t error_code);
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.
+ *
  * Initializes |pri_spec| with the |stream_id| of the stream to depend
  * on with |weight| and its exclusive flag.  If |exclusive| is
  * nonzero, exclusive flag is set.
@@ -3872,6 +4452,12 @@ NGHTTP2_EXTERN void nghttp2_priority_spec_init(nghttp2_priority_spec *pri_spec,
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.
+ *
  * Initializes |pri_spec| with the default values.  The default values
  * are: stream_id = 0, weight = :macro:`NGHTTP2_DEFAULT_WEIGHT` and
  * exclusive = 0.
@@ -3882,18 +4468,29 @@ nghttp2_priority_spec_default_init(nghttp2_priority_spec *pri_spec);
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.
+ *
  * Returns nonzero if the |pri_spec| is filled with default values.
  */
 NGHTTP2_EXTERN int
 nghttp2_priority_spec_check_default(const nghttp2_priority_spec *pri_spec);
 
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use `nghttp2_submit_request2()` instead.
+ *
  * Submits HEADERS frame and optionally one or more DATA frames.
  *
- * The |pri_spec| is priority specification of this request.  ``NULL``
- * means the default priority (see
+ * The |pri_spec| is a deprecated priority specification of this
+ * request.  ``NULL`` means the default priority (see
  * `nghttp2_priority_spec_default_init()`).  To specify the priority,
  * use `nghttp2_priority_spec_init()`.  If |pri_spec| is not ``NULL``,
  * this function will copy its data members.
@@ -3974,9 +4571,105 @@ NGHTTP2_EXTERN int32_t nghttp2_submit_request(
     const nghttp2_nv *nva, size_t nvlen, const nghttp2_data_provider *data_prd,
     void *stream_user_data);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
 /**
  * @function
  *
+ * Submits HEADERS frame and optionally one or more DATA frames.
+ *
+ * The |pri_spec| is a deprecated priority specification of this
+ * request.  ``NULL`` means the default priority (see
+ * `nghttp2_priority_spec_default_init()`).  To specify the priority,
+ * use `nghttp2_priority_spec_init()`.  If |pri_spec| is not ``NULL``,
+ * this function will copy its data members.  In the future release
+ * after the end of 2024, this function will ignore |pri_spec| and
+ * behave as if ``NULL`` is given.
+ *
+ * The ``pri_spec->weight`` must be in [:macro:`NGHTTP2_MIN_WEIGHT`,
+ * :macro:`NGHTTP2_MAX_WEIGHT`], inclusive.  If ``pri_spec->weight``
+ * is strictly less than :macro:`NGHTTP2_MIN_WEIGHT`, it becomes
+ * :macro:`NGHTTP2_MIN_WEIGHT`.  If it is strictly greater than
+ * :macro:`NGHTTP2_MAX_WEIGHT`, it becomes
+ * :macro:`NGHTTP2_MAX_WEIGHT`.
+ *
+ * If
+ * :enum:`nghttp2_settings_id.NGHTTP2_SETTINGS_NO_RFC7540_PRIORITIES`
+ * of value of 1 is received by a remote endpoint, |pri_spec| is
+ * ignored, and treated as if ``NULL`` is specified.
+ *
+ * The |nva| is an array of name/value pair :type:`nghttp2_nv` with
+ * |nvlen| elements.  The application is responsible to include
+ * required pseudo-header fields (header field whose name starts with
+ * ":") in |nva| and must place pseudo-headers before regular header
+ * fields.
+ *
+ * This function creates copies of all name/value pairs in |nva|.  It
+ * also lower-cases all names in |nva|.  The order of elements in
+ * |nva| is preserved.  For header fields with
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_NAME` and
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_VALUE` are set,
+ * header field name and value are not copied respectively.  With
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_NAME`, application
+ * is responsible to pass header field name in lowercase.  The
+ * application should maintain the references to them until
+ * :type:`nghttp2_on_frame_send_callback` or
+ * :type:`nghttp2_on_frame_not_send_callback` is called.
+ *
+ * HTTP/2 specification has requirement about header fields in the
+ * request HEADERS.  See the specification for more details.
+ *
+ * If |data_prd| is not ``NULL``, it provides data which will be sent
+ * in subsequent DATA frames.  In this case, a method that allows
+ * request message bodies
+ * (https://tools.ietf.org/html/rfc7231#section-4) must be specified
+ * with ``:method`` key in |nva| (e.g. ``POST``).  This function does
+ * not take ownership of the |data_prd|.  The function copies the
+ * members of the |data_prd|.  If |data_prd| is ``NULL``, HEADERS have
+ * END_STREAM set.  The |stream_user_data| is data associated to the
+ * stream opened by this request and can be an arbitrary pointer,
+ * which can be retrieved later by
+ * `nghttp2_session_get_stream_user_data()`.
+ *
+ * This function returns assigned stream ID if it succeeds, or one of
+ * the following negative error codes:
+ *
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
+ *     Out of memory.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_STREAM_ID_NOT_AVAILABLE`
+ *     No stream ID is available because maximum stream ID was
+ *     reached.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
+ *     Trying to depend on itself (new stream ID equals
+ *     ``pri_spec->stream_id``).
+ * :enum:`nghttp2_error.NGHTTP2_ERR_PROTO`
+ *     The |session| is server session.
+ *
+ * .. warning::
+ *
+ *   This function returns assigned stream ID if it succeeds.  But
+ *   that stream is not created yet.  The application must not submit
+ *   frame to that stream ID before
+ *   :type:`nghttp2_before_frame_send_callback` is called for this
+ *   frame.  This means `nghttp2_session_get_stream_user_data()` does
+ *   not work before the callback.  But
+ *   `nghttp2_session_set_stream_user_data()` handles this situation
+ *   specially, and it can set data to a stream during this period.
+ *
+ */
+NGHTTP2_EXTERN int32_t nghttp2_submit_request2(
+    nghttp2_session *session, const nghttp2_priority_spec *pri_spec,
+    const nghttp2_nv *nva, size_t nvlen, const nghttp2_data_provider2 *data_prd,
+    void *stream_user_data);
+
+#ifndef NGHTTP2_NO_SSIZE_T
+/**
+ * @function
+ *
+ * .. warning::
+ *
+ *   Deprecated.  Use `nghttp2_submit_response2()` instead.
+ *
  * Submits response HEADERS frame and optionally one or more DATA
  * frames against the stream |stream_id|.
  *
@@ -4043,6 +4736,77 @@ nghttp2_submit_response(nghttp2_session *session, int32_t stream_id,
                         const nghttp2_nv *nva, size_t nvlen,
                         const nghttp2_data_provider *data_prd);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @function
+ *
+ * Submits response HEADERS frame and optionally one or more DATA
+ * frames against the stream |stream_id|.
+ *
+ * The |nva| is an array of name/value pair :type:`nghttp2_nv` with
+ * |nvlen| elements.  The application is responsible to include
+ * required pseudo-header fields (header field whose name starts with
+ * ":") in |nva| and must place pseudo-headers before regular header
+ * fields.
+ *
+ * This function creates copies of all name/value pairs in |nva|.  It
+ * also lower-cases all names in |nva|.  The order of elements in
+ * |nva| is preserved.  For header fields with
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_NAME` and
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_VALUE` are set,
+ * header field name and value are not copied respectively.  With
+ * :enum:`nghttp2_nv_flag.NGHTTP2_NV_FLAG_NO_COPY_NAME`, application
+ * is responsible to pass header field name in lowercase.  The
+ * application should maintain the references to them until
+ * :type:`nghttp2_on_frame_send_callback` or
+ * :type:`nghttp2_on_frame_not_send_callback` is called.
+ *
+ * HTTP/2 specification has requirement about header fields in the
+ * response HEADERS.  See the specification for more details.
+ *
+ * If |data_prd| is not ``NULL``, it provides data which will be sent
+ * in subsequent DATA frames.  This function does not take ownership
+ * of the |data_prd|.  The function copies the members of the
+ * |data_prd|.  If |data_prd| is ``NULL``, HEADERS will have
+ * END_STREAM flag set.
+ *
+ * This method can be used as normal HTTP response and push response.
+ * When pushing a resource using this function, the |session| must be
+ * configured using `nghttp2_session_server_new()` or its variants and
+ * the target stream denoted by the |stream_id| must be reserved using
+ * `nghttp2_submit_push_promise()`.
+ *
+ * To send non-final response headers (e.g., HTTP status 101), don't
+ * use this function because this function half-closes the outbound
+ * stream.  Instead, use `nghttp2_submit_headers()` for this purpose.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
+ *     Out of memory.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
+ *     The |stream_id| is 0.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_DATA_EXIST`
+ *     DATA or HEADERS has been already submitted and not fully
+ *     processed yet.  Normally, this does not happen, but when
+ *     application wrongly calls `nghttp2_submit_response2()` twice,
+ *     this may happen.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_PROTO`
+ *     The |session| is client session.
+ *
+ * .. warning::
+ *
+ *   Calling this function twice for the same stream ID may lead to
+ *   program crash.  It is generally considered to a programming error
+ *   to commit response twice.
+ */
+NGHTTP2_EXTERN int
+nghttp2_submit_response2(nghttp2_session *session, int32_t stream_id,
+                         const nghttp2_nv *nva, size_t nvlen,
+                         const nghttp2_data_provider2 *data_prd);
+
 /**
  * @function
  *
@@ -4068,22 +4832,23 @@ nghttp2_submit_response(nghttp2_session *session, int32_t stream_id,
  * DATA without END_STREAM flat set.  The library does not enforce
  * this requirement, and applications should do this for themselves.
  * If `nghttp2_submit_trailer()` is called before any response HEADERS
- * submission (usually by `nghttp2_submit_response()`), the content of
- * |nva| will be sent as response headers, which will result in error.
+ * submission (usually by `nghttp2_submit_response2()`), the content
+ * of |nva| will be sent as response headers, which will result in
+ * error.
  *
  * This function has the same effect with `nghttp2_submit_headers()`,
  * with flags = :enum:`nghttp2_flag.NGHTTP2_FLAG_END_STREAM` and both
  * pri_spec and stream_user_data to NULL.
  *
- * To submit trailer fields after `nghttp2_submit_response()` is
+ * To submit trailer fields after `nghttp2_submit_response2()` is
  * called, the application has to specify
- * :type:`nghttp2_data_provider` to `nghttp2_submit_response()`.
- * Inside of :type:`nghttp2_data_source_read_callback`, when setting
+ * :type:`nghttp2_data_provider2` to `nghttp2_submit_response2()`.
+ * Inside of :type:`nghttp2_data_source_read_callback2`, when setting
  * :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_EOF`, also set
  * :enum:`nghttp2_data_flag.NGHTTP2_DATA_FLAG_NO_END_STREAM`.  After
  * that, the application can send trailer fields using
  * `nghttp2_submit_trailer()`.  `nghttp2_submit_trailer()` can be used
- * inside :type:`nghttp2_data_source_read_callback`.
+ * inside :type:`nghttp2_data_source_read_callback2`.
  *
  * This function returns 0 if it succeeds and |stream_id| is -1.
  * Otherwise, this function returns 0 if it succeeds, or one of the
@@ -4118,11 +4883,13 @@ NGHTTP2_EXTERN int nghttp2_submit_trailer(nghttp2_session *session,
  * assigned stream ID will be returned.  Otherwise, specify stream ID
  * in |stream_id|.
  *
- * The |pri_spec| is priority specification of this request.  ``NULL``
- * means the default priority (see
+ * The |pri_spec| is a deprecated priority specification of this
+ * request.  ``NULL`` means the default priority (see
  * `nghttp2_priority_spec_default_init()`).  To specify the priority,
  * use `nghttp2_priority_spec_init()`.  If |pri_spec| is not ``NULL``,
- * this function will copy its data members.
+ * this function will copy its data members.  In the future release
+ * after the end of 2024, this function will ignore |pri_spec| and
+ * behave as if ``NULL`` is given.
  *
  * The ``pri_spec->weight`` must be in [:macro:`NGHTTP2_MIN_WEIGHT`,
  * :macro:`NGHTTP2_MAX_WEIGHT`], inclusive.  If ``pri_spec->weight``
@@ -4160,8 +4927,8 @@ NGHTTP2_EXTERN int nghttp2_submit_trailer(nghttp2_session *session,
  *
  * This function is low-level in a sense that the application code can
  * specify flags directly.  For usual HTTP request,
- * `nghttp2_submit_request()` is useful.  Likewise, for HTTP response,
- * prefer `nghttp2_submit_response()`.
+ * `nghttp2_submit_request2()` is useful.  Likewise, for HTTP
+ * response, prefer `nghttp2_submit_response2()`.
  *
  * This function returns newly assigned stream ID if it succeeds and
  * |stream_id| is -1.  Otherwise, this function returns 0 if it
@@ -4196,9 +4963,14 @@ NGHTTP2_EXTERN int32_t nghttp2_submit_headers(
     const nghttp2_priority_spec *pri_spec, const nghttp2_nv *nva, size_t nvlen,
     void *stream_user_data);
 
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use `nghttp2_submit_data2()` instead.
+ *
  * Submits one or more DATA frames to the stream |stream_id|.  The
  * data to be sent are provided by |data_prd|.  If |flags| contains
  * :enum:`nghttp2_flag.NGHTTP2_FLAG_END_STREAM`, the last DATA frame
@@ -4241,19 +5013,73 @@ NGHTTP2_EXTERN int nghttp2_submit_data(nghttp2_session *session, uint8_t flags,
                                        int32_t stream_id,
                                        const nghttp2_data_provider *data_prd);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
 /**
  * @function
  *
+ * Submits one or more DATA frames to the stream |stream_id|.  The
+ * data to be sent are provided by |data_prd|.  If |flags| contains
+ * :enum:`nghttp2_flag.NGHTTP2_FLAG_END_STREAM`, the last DATA frame
+ * has END_STREAM flag set.
+ *
+ * This function does not take ownership of the |data_prd|.  The
+ * function copies the members of the |data_prd|.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
+ *     Out of memory.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_DATA_EXIST`
+ *     DATA or HEADERS has been already submitted and not fully
+ *     processed yet.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
+ *     The |stream_id| is 0.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_STREAM_CLOSED`
+ *     The stream was already closed; or the |stream_id| is invalid.
+ *
+ * .. note::
+ *
+ *   Currently, only one DATA or HEADERS is allowed for a stream at a
+ *   time.  Submitting these frames more than once before first DATA
+ *   or HEADERS is finished results in
+ *   :enum:`nghttp2_error.NGHTTP2_ERR_DATA_EXIST` error code.  The
+ *   earliest callback which tells that previous frame is done is
+ *   :type:`nghttp2_on_frame_send_callback`.  In side that callback,
+ *   new data can be submitted using `nghttp2_submit_data2()`.  Of
+ *   course, all data except for last one must not have
+ *   :enum:`nghttp2_flag.NGHTTP2_FLAG_END_STREAM` flag set in |flags|.
+ *   This sounds a bit complicated, and we recommend to use
+ *   `nghttp2_submit_request2()` and `nghttp2_submit_response2()` to
+ *   avoid this cascading issue.  The experience shows that for HTTP
+ *   use, these two functions are enough to implement both client and
+ *   server.
+ */
+NGHTTP2_EXTERN int nghttp2_submit_data2(nghttp2_session *session, uint8_t flags,
+                                        int32_t stream_id,
+                                        const nghttp2_data_provider2 *data_prd);
+
+/**
+ * @function
+ *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.  In the future release after the end of
+ *   2024, this function will always return 0 without doing anything.
+ *
  * Submits PRIORITY frame to change the priority of stream |stream_id|
  * to the priority specification |pri_spec|.
  *
  * The |flags| is currently ignored and should be
  * :enum:`nghttp2_flag.NGHTTP2_FLAG_NONE`.
  *
- * The |pri_spec| is priority specification of this request.  ``NULL``
- * is not allowed for this function. To specify the priority, use
- * `nghttp2_priority_spec_init()`.  This function will copy its data
- * members.
+ * The |pri_spec| is a deprecated priority specification of this
+ * request.  ``NULL`` is not allowed for this function. To specify the
+ * priority, use `nghttp2_priority_spec_init()`.  This function will
+ * copy its data members.
  *
  * The ``pri_spec->weight`` must be in [:macro:`NGHTTP2_MIN_WEIGHT`,
  * :macro:`NGHTTP2_MAX_WEIGHT`], inclusive.  If ``pri_spec->weight``
@@ -4433,7 +5259,7 @@ NGHTTP2_EXTERN int nghttp2_submit_settings(nghttp2_session *session,
  * The client side is not allowed to use this function.
  *
  * To submit response headers and data, use
- * `nghttp2_submit_response()`.
+ * `nghttp2_submit_response2()`.
  *
  * This function returns assigned promised stream ID if it succeeds,
  * or one of the following negative error codes:
@@ -4572,10 +5398,11 @@ nghttp2_session_get_last_proc_stream_id(nghttp2_session *session);
  * reasons are: session is server; stream ID has been spent; GOAWAY
  * has been sent or received.
  *
- * The application can call `nghttp2_submit_request()` without
- * consulting this function.  In that case, `nghttp2_submit_request()`
- * may return error.  Or, request is failed to sent, and
- * :type:`nghttp2_on_stream_close_callback` is called.
+ * The application can call `nghttp2_submit_request2()` without
+ * consulting this function.  In that case,
+ * `nghttp2_submit_request2()` may return error.  Or, request is
+ * failed to sent, and :type:`nghttp2_on_stream_close_callback` is
+ * called.
  */
 NGHTTP2_EXTERN int
 nghttp2_session_check_request_allowed(nghttp2_session *session);
@@ -4677,11 +5504,11 @@ nghttp2_session_set_local_window_size(nghttp2_session *session, uint8_t flags,
  * Application can pass arbitrary frame flags and stream ID in |flags|
  * and |stream_id| respectively.  The |payload| is opaque pointer, and
  * it can be accessible though ``frame->ext.payload`` in
- * :type:`nghttp2_pack_extension_callback`.  The library will not own
+ * :type:`nghttp2_pack_extension_callback2`.  The library will not own
  * passed |payload| pointer.
  *
- * The application must set :type:`nghttp2_pack_extension_callback`
- * using `nghttp2_session_callbacks_set_pack_extension_callback()`.
+ * The application must set :type:`nghttp2_pack_extension_callback2`
+ * using `nghttp2_session_callbacks_set_pack_extension_callback2()`.
  *
  * The application should retain the memory pointed by |payload| until
  * the transmission of extension frame is done (which is indicated by
@@ -4689,7 +5516,7 @@ nghttp2_session_set_local_window_size(nghttp2_session *session, uint8_t flags,
  * (which is indicated by :type:`nghttp2_on_frame_not_send_callback`).
  * If application does not touch this memory region after packing it
  * into a wire format, application can free it inside
- * :type:`nghttp2_pack_extension_callback`.
+ * :type:`nghttp2_pack_extension_callback2`.
  *
  * The standard HTTP/2 frame cannot be sent with this function, so
  * |type| must be strictly grater than 0x9.  Otherwise, this function
@@ -4700,7 +5527,7 @@ nghttp2_session_set_local_window_size(nghttp2_session *session, uint8_t flags,
  * negative error codes:
  *
  * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_STATE`
- *     If :type:`nghttp2_pack_extension_callback` is not set.
+ *     If :type:`nghttp2_pack_extension_callback2` is not set.
  * :enum:`nghttp2_error.NGHTTP2_ERR_INVALID_ARGUMENT`
  *     If  |type| specifies  standard  HTTP/2 frame  type.  The  frame
  *     types  in the  rage [0x0,  0x9], both  inclusive, are  standard
@@ -5321,9 +6148,14 @@ NGHTTP2_EXTERN int
 nghttp2_hd_deflate_change_table_size(nghttp2_hd_deflater *deflater,
                                      size_t settings_max_dynamic_table_size);
 
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use `nghttp2_hd_deflate_hd2()` instead.
+ *
  * Deflates the |nva|, which has the |nvlen| name/value pairs, into
  * the |buf| of length |buflen|.
  *
@@ -5353,9 +6185,47 @@ NGHTTP2_EXTERN ssize_t nghttp2_hd_deflate_hd(nghttp2_hd_deflater *deflater,
                                              const nghttp2_nv *nva,
                                              size_t nvlen);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @function
+ *
+ * Deflates the |nva|, which has the |nvlen| name/value pairs, into
+ * the |buf| of length |buflen|.
+ *
+ * If |buf| is not large enough to store the deflated header block,
+ * this function fails with
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INSUFF_BUFSIZE`.  The caller
+ * should use `nghttp2_hd_deflate_bound()` to know the upper bound of
+ * buffer size required to deflate given header name/value pairs.
+ *
+ * Once this function fails, subsequent call of this function always
+ * returns :enum:`nghttp2_error.NGHTTP2_ERR_HEADER_COMP`.
+ *
+ * After this function returns, it is safe to delete the |nva|.
+ *
+ * This function returns the number of bytes written to |buf| if it
+ * succeeds, or one of the following negative error codes:
+ *
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
+ *     Out of memory.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_HEADER_COMP`
+ *     Deflation process has failed.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INSUFF_BUFSIZE`
+ *     The provided |buflen| size is too small to hold the output.
+ */
+NGHTTP2_EXTERN nghttp2_ssize
+nghttp2_hd_deflate_hd2(nghttp2_hd_deflater *deflater, uint8_t *buf,
+                       size_t buflen, const nghttp2_nv *nva, size_t nvlen);
+
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use `nghttp2_hd_deflate_hd_vec2()` instead.
+ *
  * Deflates the |nva|, which has the |nvlen| name/value pairs, into
  * the |veclen| size of buf vector |vec|.  The each size of buffer
  * must be set in len field of :type:`nghttp2_vec`.  If and only if
@@ -5387,6 +6257,40 @@ NGHTTP2_EXTERN ssize_t nghttp2_hd_deflate_hd_vec(nghttp2_hd_deflater *deflater,
                                                  const nghttp2_nv *nva,
                                                  size_t nvlen);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @function
+ *
+ * Deflates the |nva|, which has the |nvlen| name/value pairs, into
+ * the |veclen| size of buf vector |vec|.  The each size of buffer
+ * must be set in len field of :type:`nghttp2_vec`.  If and only if
+ * one chunk is filled up completely, next chunk will be used.  If
+ * |vec| is not large enough to store the deflated header block, this
+ * function fails with
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INSUFF_BUFSIZE`.  The caller
+ * should use `nghttp2_hd_deflate_bound()` to know the upper bound of
+ * buffer size required to deflate given header name/value pairs.
+ *
+ * Once this function fails, subsequent call of this function always
+ * returns :enum:`nghttp2_error.NGHTTP2_ERR_HEADER_COMP`.
+ *
+ * After this function returns, it is safe to delete the |nva|.
+ *
+ * This function returns the number of bytes written to |vec| if it
+ * succeeds, or one of the following negative error codes:
+ *
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
+ *     Out of memory.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_HEADER_COMP`
+ *     Deflation process has failed.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_INSUFF_BUFSIZE`
+ *     The provided |buflen| size is too small to hold the output.
+ */
+NGHTTP2_EXTERN nghttp2_ssize nghttp2_hd_deflate_hd_vec2(
+    nghttp2_hd_deflater *deflater, const nghttp2_vec *vec, size_t veclen,
+    const nghttp2_nv *nva, size_t nvlen);
+
 /**
  * @function
  *
@@ -5500,7 +6404,7 @@ NGHTTP2_EXTERN void nghttp2_hd_inflate_del(nghttp2_hd_inflater *inflater);
  * This function must not be called while header block is being
  * inflated.  In other words, this function must be called after
  * initialization of |inflater|, but before calling
- * `nghttp2_hd_inflate_hd2()`, or after
+ * `nghttp2_hd_inflate_hd3()`, or after
  * `nghttp2_hd_inflate_end_headers()`.  Otherwise,
  * `NGHTTP2_ERR_INVALID_STATE` was returned.
  *
@@ -5538,6 +6442,7 @@ typedef enum {
   NGHTTP2_HD_INFLATE_EMIT = 0x02
 } nghttp2_hd_inflate_flag;
 
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @function
  *
@@ -5625,9 +6530,16 @@ NGHTTP2_EXTERN ssize_t nghttp2_hd_inflate_hd(nghttp2_hd_inflater *inflater,
                                              int *inflate_flags, uint8_t *in,
                                              size_t inlen, int in_final);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+#ifndef NGHTTP2_NO_SSIZE_T
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  Use `nghttp2_hd_inflate_hd3()` instead.
+ *
  * Inflates name/value block stored in |in| with length |inlen|.  This
  * function performs decompression.  For each successful emission of
  * header name/value pair,
@@ -5714,6 +6626,95 @@ NGHTTP2_EXTERN ssize_t nghttp2_hd_inflate_hd2(nghttp2_hd_inflater *inflater,
                                               const uint8_t *in, size_t inlen,
                                               int in_final);
 
+#endif /* NGHTTP2_NO_SSIZE_T */
+
+/**
+ * @function
+ *
+ * Inflates name/value block stored in |in| with length |inlen|.  This
+ * function performs decompression.  For each successful emission of
+ * header name/value pair,
+ * :enum:`nghttp2_hd_inflate_flag.NGHTTP2_HD_INFLATE_EMIT` is set in
+ * |*inflate_flags| and name/value pair is assigned to the |nv_out|
+ * and the function returns.  The caller must not free the members of
+ * |nv_out|.
+ *
+ * The |nv_out| may include pointers to the memory region in the |in|.
+ * The caller must retain the |in| while the |nv_out| is used.
+ *
+ * The application should call this function repeatedly until the
+ * ``(*inflate_flags) & NGHTTP2_HD_INFLATE_FINAL`` is nonzero and
+ * return value is non-negative.  If that happens, all given input
+ * data (|inlen| bytes) are processed successfully.  Then the
+ * application must call `nghttp2_hd_inflate_end_headers()` to prepare
+ * for the next header block input.
+ *
+ * In other words, if |in_final| is nonzero, and this function returns
+ * |inlen|, you can assert that
+ * :enum:`nghttp2_hd_inflate_final.NGHTTP2_HD_INFLATE_FINAL` is set in
+ * |*inflate_flags|.
+ *
+ * The caller can feed complete compressed header block.  It also can
+ * feed it in several chunks.  The caller must set |in_final| to
+ * nonzero if the given input is the last block of the compressed
+ * header.
+ *
+ * This function returns the number of bytes processed if it succeeds,
+ * or one of the following negative error codes:
+ *
+ * :enum:`nghttp2_error.NGHTTP2_ERR_NOMEM`
+ *     Out of memory.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_HEADER_COMP`
+ *     Inflation process has failed.
+ * :enum:`nghttp2_error.NGHTTP2_ERR_BUFFER_ERROR`
+ *     The header field name or value is too large.
+ *
+ * Example follows::
+ *
+ *     int inflate_header_block(nghttp2_hd_inflater *hd_inflater,
+ *                              uint8_t *in, size_t inlen, int final)
+ *     {
+ *         nghttp2_ssize rv;
+ *
+ *         for(;;) {
+ *             nghttp2_nv nv;
+ *             int inflate_flags = 0;
+ *
+ *             rv = nghttp2_hd_inflate_hd3(hd_inflater, &nv, &inflate_flags,
+ *                                         in, inlen, final);
+ *
+ *             if(rv < 0) {
+ *                 fprintf(stderr, "inflate failed with error code %td", rv);
+ *                 return -1;
+ *             }
+ *
+ *             in += rv;
+ *             inlen -= rv;
+ *
+ *             if(inflate_flags & NGHTTP2_HD_INFLATE_EMIT) {
+ *                 fwrite(nv.name, nv.namelen, 1, stderr);
+ *                 fprintf(stderr, ": ");
+ *                 fwrite(nv.value, nv.valuelen, 1, stderr);
+ *                 fprintf(stderr, "\n");
+ *             }
+ *             if(inflate_flags & NGHTTP2_HD_INFLATE_FINAL) {
+ *                 nghttp2_hd_inflate_end_headers(hd_inflater);
+ *                 break;
+ *             }
+ *             if((inflate_flags & NGHTTP2_HD_INFLATE_EMIT) == 0 &&
+ *                inlen == 0) {
+ *                break;
+ *             }
+ *         }
+ *
+ *         return 0;
+ *     }
+ *
+ */
+NGHTTP2_EXTERN nghttp2_ssize nghttp2_hd_inflate_hd3(
+    nghttp2_hd_inflater *inflater, nghttp2_nv *nv_out, int *inflate_flags,
+    const uint8_t *in, size_t inlen, int in_final);
+
 /**
  * @function
  *
@@ -5787,8 +6788,8 @@ typedef struct nghttp2_stream nghttp2_stream;
  * `nghttp2_session_get_root_stream()`) if 0 is given in |stream_id|.
  *
  * Unless |stream_id| == 0, the returned pointer is valid until next
- * call of `nghttp2_session_send()`, `nghttp2_session_mem_send()`,
- * `nghttp2_session_recv()`, and `nghttp2_session_mem_recv()`.
+ * call of `nghttp2_session_send()`, `nghttp2_session_mem_send2()`,
+ * `nghttp2_session_recv()`, and `nghttp2_session_mem_recv2()`.
  */
 NGHTTP2_EXTERN nghttp2_stream *
 nghttp2_session_find_stream(nghttp2_session *session, int32_t stream_id);
@@ -5842,6 +6843,12 @@ nghttp2_stream_get_state(nghttp2_stream *stream);
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.
+ *
  * Returns root of dependency tree, which is imaginary stream with
  * stream ID 0.  The returned pointer is valid until |session| is
  * freed by `nghttp2_session_del()`.
@@ -5852,6 +6859,13 @@ nghttp2_session_get_root_stream(nghttp2_session *session);
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.  In the future release after the end of
+ *   2024, this function will always return NULL.
+ *
  * Returns the parent stream of |stream| in dependency tree.  Returns
  * NULL if there is no such stream.
  */
@@ -5863,6 +6877,13 @@ NGHTTP2_EXTERN int32_t nghttp2_stream_get_stream_id(nghttp2_stream *stream);
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.  In the future release after the end of
+ *   2024, this function will always return NULL.
+ *
  * Returns the next sibling stream of |stream| in dependency tree.
  * Returns NULL if there is no such stream.
  */
@@ -5872,6 +6893,13 @@ nghttp2_stream_get_next_sibling(nghttp2_stream *stream);
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.  In the future release after the end of
+ *   2024, this function will always return NULL.
+ *
  * Returns the previous sibling stream of |stream| in dependency tree.
  * Returns NULL if there is no such stream.
  */
@@ -5881,6 +6909,13 @@ nghttp2_stream_get_previous_sibling(nghttp2_stream *stream);
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.  In the future release after the end of
+ *   2024, this function will always return NULL.
+ *
  * Returns the first child stream of |stream| in dependency tree.
  * Returns NULL if there is no such stream.
  */
@@ -5890,6 +6925,14 @@ nghttp2_stream_get_first_child(nghttp2_stream *stream);
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.  In the future release after the end of
+ *   2024, this function will always return
+ *   :macro:`NGHTTP2_DEFAULT_WEIGHT`.
+ *
  * Returns dependency weight to the parent stream of |stream|.
  */
 NGHTTP2_EXTERN int32_t nghttp2_stream_get_weight(nghttp2_stream *stream);
@@ -5897,6 +6940,13 @@ NGHTTP2_EXTERN int32_t nghttp2_stream_get_weight(nghttp2_stream *stream);
 /**
  * @function
  *
+ * .. warning::
+ *
+ *   Deprecated.  :rfc:`7540` priorities are deprecated by
+ *   :rfc:`9113`.  Consider migrating to :rfc:`9218` extensible
+ *   prioritization scheme.  In the future release after the end of
+ *   2024, this function will always return 0.
+ *
  * Returns the sum of the weight for |stream|'s children.
  */
 NGHTTP2_EXTERN int32_t
diff --git a/contrib/libs/nghttp2/lib/includes/nghttp2/nghttp2ver.h b/contrib/libs/nghttp2/lib/includes/nghttp2/nghttp2ver.h
index 518755bbab..d38b89adc6 100644
--- a/contrib/libs/nghttp2/lib/includes/nghttp2/nghttp2ver.h
+++ b/contrib/libs/nghttp2/lib/includes/nghttp2/nghttp2ver.h
@@ -29,7 +29,7 @@
  * @macro
  * Version number of the nghttp2 library release
  */
-#define NGHTTP2_VERSION "1.59.0"
+#define NGHTTP2_VERSION "1.60.0"
 
 /**
  * @macro
@@ -37,6 +37,6 @@
  * release. This is a 24 bit number with 8 bits for major number, 8 bits
  * for minor and 8 bits for patch. Version 1.2.3 becomes 0x010203.
  */
-#define NGHTTP2_VERSION_NUM 0x013b00
+#define NGHTTP2_VERSION_NUM 0x013c00
 
 #endif /* NGHTTP2VER_H */
diff --git a/contrib/libs/nghttp2/lib/nghttp2_buf.c b/contrib/libs/nghttp2/lib/nghttp2_buf.c
index a32844712e..101035f923 100644
--- a/contrib/libs/nghttp2/lib/nghttp2_buf.c
+++ b/contrib/libs/nghttp2/lib/nghttp2_buf.c
@@ -430,7 +430,7 @@ int nghttp2_bufs_orb_hold(nghttp2_bufs *bufs, uint8_t b) {
   return 0;
 }
 
-ssize_t nghttp2_bufs_remove(nghttp2_bufs *bufs, uint8_t **out) {
+nghttp2_ssize nghttp2_bufs_remove(nghttp2_bufs *bufs, uint8_t **out) {
   size_t len;
   nghttp2_buf_chain *chain;
   nghttp2_buf *buf;
@@ -462,7 +462,7 @@ ssize_t nghttp2_bufs_remove(nghttp2_bufs *bufs, uint8_t **out) {
 
   *out = res;
 
-  return (ssize_t)len;
+  return (nghttp2_ssize)len;
 }
 
 size_t nghttp2_bufs_remove_copy(nghttp2_bufs *bufs, uint8_t *out) {
diff --git a/contrib/libs/nghttp2/lib/nghttp2_buf.h b/contrib/libs/nghttp2/lib/nghttp2_buf.h
index 45f62f16e2..95ff3706a2 100644
--- a/contrib/libs/nghttp2/lib/nghttp2_buf.h
+++ b/contrib/libs/nghttp2/lib/nghttp2_buf.h
@@ -349,7 +349,7 @@ int nghttp2_bufs_orb_hold(nghttp2_bufs *bufs, uint8_t b);
  * NGHTTP2_ERR_NOMEM
  *     Out of memory
  */
-ssize_t nghttp2_bufs_remove(nghttp2_bufs *bufs, uint8_t **out);
+nghttp2_ssize nghttp2_bufs_remove(nghttp2_bufs *bufs, uint8_t **out);
 
 /*
  * Copies all data stored in |bufs| to |out|.  This function assumes
diff --git a/contrib/libs/nghttp2/lib/nghttp2_callbacks.c b/contrib/libs/nghttp2/lib/nghttp2_callbacks.c
index 3c38214859..1776f7d276 100644
--- a/contrib/libs/nghttp2/lib/nghttp2_callbacks.c
+++ b/contrib/libs/nghttp2/lib/nghttp2_callbacks.c
@@ -45,11 +45,21 @@ void nghttp2_session_callbacks_set_send_callback(
   cbs->send_callback = send_callback;
 }
 
+void nghttp2_session_callbacks_set_send_callback2(
+    nghttp2_session_callbacks *cbs, nghttp2_send_callback2 send_callback) {
+  cbs->send_callback2 = send_callback;
+}
+
 void nghttp2_session_callbacks_set_recv_callback(
     nghttp2_session_callbacks *cbs, nghttp2_recv_callback recv_callback) {
   cbs->recv_callback = recv_callback;
 }
 
+void nghttp2_session_callbacks_set_recv_callback2(
+    nghttp2_session_callbacks *cbs, nghttp2_recv_callback2 recv_callback) {
+  cbs->recv_callback2 = recv_callback;
+}
+
 void nghttp2_session_callbacks_set_on_frame_recv_callback(
     nghttp2_session_callbacks *cbs,
     nghttp2_on_frame_recv_callback on_frame_recv_callback) {
@@ -128,12 +138,24 @@ void nghttp2_session_callbacks_set_select_padding_callback(
   cbs->select_padding_callback = select_padding_callback;
 }
 
+void nghttp2_session_callbacks_set_select_padding_callback2(
+    nghttp2_session_callbacks *cbs,
+    nghttp2_select_padding_callback2 select_padding_callback) {
+  cbs->select_padding_callback2 = select_padding_callback;
+}
+
 void nghttp2_session_callbacks_set_data_source_read_length_callback(
     nghttp2_session_callbacks *cbs,
     nghttp2_data_source_read_length_callback data_source_read_length_callback) {
   cbs->read_length_callback = data_source_read_length_callback;
 }
 
+void nghttp2_session_callbacks_set_data_source_read_length_callback2(
+    nghttp2_session_callbacks *cbs, nghttp2_data_source_read_length_callback2
+                                        data_source_read_length_callback) {
+  cbs->read_length_callback2 = data_source_read_length_callback;
+}
+
 void nghttp2_session_callbacks_set_on_begin_frame_callback(
     nghttp2_session_callbacks *cbs,
     nghttp2_on_begin_frame_callback on_begin_frame_callback) {
@@ -152,6 +174,12 @@ void nghttp2_session_callbacks_set_pack_extension_callback(
   cbs->pack_extension_callback = pack_extension_callback;
 }
 
+void nghttp2_session_callbacks_set_pack_extension_callback2(
+    nghttp2_session_callbacks *cbs,
+    nghttp2_pack_extension_callback2 pack_extension_callback) {
+  cbs->pack_extension_callback2 = pack_extension_callback;
+}
+
 void nghttp2_session_callbacks_set_unpack_extension_callback(
     nghttp2_session_callbacks *cbs,
     nghttp2_unpack_extension_callback unpack_extension_callback) {
diff --git a/contrib/libs/nghttp2/lib/nghttp2_callbacks.h b/contrib/libs/nghttp2/lib/nghttp2_callbacks.h
index 61e51fa536..a611f48548 100644
--- a/contrib/libs/nghttp2/lib/nghttp2_callbacks.h
+++ b/contrib/libs/nghttp2/lib/nghttp2_callbacks.h
@@ -36,19 +36,33 @@
  */
 struct nghttp2_session_callbacks {
   /**
+   * Deprecated.  Use send_callback2 instead.  Callback function
+   * invoked when the session wants to send data to the remote peer.
+   * This callback is not necessary if the application uses solely
+   * `nghttp2_session_mem_send()` to serialize data to transmit.
+   */
+  nghttp2_send_callback send_callback;
+  /**
    * Callback function invoked when the session wants to send data to
    * the remote peer.  This callback is not necessary if the
-   * application uses solely `nghttp2_session_mem_send()` to serialize
-   * data to transmit.
+   * application uses solely `nghttp2_session_mem_send2()` to
+   * serialize data to transmit.
    */
-  nghttp2_send_callback send_callback;
+  nghttp2_send_callback2 send_callback2;
+  /**
+   * Deprecated.  Use recv_callback2 instead.  Callback function
+   * invoked when the session wants to receive data from the remote
+   * peer.  This callback is not necessary if the application uses
+   * solely `nghttp2_session_mem_recv()` to process received data.
+   */
+  nghttp2_recv_callback recv_callback;
   /**
    * Callback function invoked when the session wants to receive data
    * from the remote peer.  This callback is not necessary if the
-   * application uses solely `nghttp2_session_mem_recv()` to process
+   * application uses solely `nghttp2_session_mem_recv2()` to process
    * received data.
    */
-  nghttp2_recv_callback recv_callback;
+  nghttp2_recv_callback2 recv_callback2;
   /**
    * Callback function invoked by `nghttp2_session_recv()` when a
    * frame is received.
@@ -100,22 +114,39 @@ struct nghttp2_session_callbacks {
   nghttp2_on_invalid_header_callback on_invalid_header_callback;
   nghttp2_on_invalid_header_callback2 on_invalid_header_callback2;
   /**
+   * Deprecated.  Use select_padding_callback2 instead.  Callback
+   * function invoked when the library asks application how many
+   * padding bytes are required for the transmission of the given
+   * frame.
+   */
+  nghttp2_select_padding_callback select_padding_callback;
+  /**
    * Callback function invoked when the library asks application how
    * many padding bytes are required for the transmission of the given
    * frame.
    */
-  nghttp2_select_padding_callback select_padding_callback;
+  nghttp2_select_padding_callback2 select_padding_callback2;
   /**
-   * The callback function used to determine the length allowed in
+   * Deprecated.  Use read_length_callback2 instead.  The callback
+   * function used to determine the length allowed in
    * `nghttp2_data_source_read_callback()`
    */
   nghttp2_data_source_read_length_callback read_length_callback;
   /**
+   * The callback function used to determine the length allowed in
+   * `nghttp2_data_source_read_callback2()`
+   */
+  nghttp2_data_source_read_length_callback2 read_length_callback2;
+  /**
    * Sets callback function invoked when a frame header is received.
    */
   nghttp2_on_begin_frame_callback on_begin_frame_callback;
   nghttp2_send_data_callback send_data_callback;
+  /**
+   * Deprecated.  Use pack_extension_callback2 instead.
+   */
   nghttp2_pack_extension_callback pack_extension_callback;
+  nghttp2_pack_extension_callback2 pack_extension_callback2;
   nghttp2_unpack_extension_callback unpack_extension_callback;
   nghttp2_on_extension_chunk_recv_callback on_extension_chunk_recv_callback;
   nghttp2_error_callback error_callback;
diff --git a/contrib/libs/nghttp2/lib/nghttp2_hd.c b/contrib/libs/nghttp2/lib/nghttp2_hd.c
index 8a2bda64c1..1b0c71331a 100644
--- a/contrib/libs/nghttp2/lib/nghttp2_hd.c
+++ b/contrib/libs/nghttp2/lib/nghttp2_hd.c
@@ -850,9 +850,10 @@ static size_t encode_length(uint8_t *buf, size_t n, size_t prefix) {
  * in the next call will be stored in |*shift_ptr|) and returns number
  * of bytes processed, or returns -1, indicating decoding error.
  */
-static ssize_t decode_length(uint32_t *res, size_t *shift_ptr, int *fin,
-                             uint32_t initial, size_t shift, const uint8_t *in,
-                             const uint8_t *last, size_t prefix) {
+static nghttp2_ssize decode_length(uint32_t *res, size_t *shift_ptr, int *fin,
+                                   uint32_t initial, size_t shift,
+                                   const uint8_t *in, const uint8_t *last,
+                                   size_t prefix) {
   uint32_t k = (uint8_t)((1 << prefix) - 1);
   uint32_t n = initial;
   const uint8_t *start = in;
@@ -871,7 +872,7 @@ static ssize_t decode_length(uint32_t *res, size_t *shift_ptr, int *fin,
 
     if (++in == last) {
       *res = n;
-      return (ssize_t)(in - start);
+      return (nghttp2_ssize)(in - start);
     }
   }
 
@@ -906,12 +907,12 @@ static ssize_t decode_length(uint32_t *res, size_t *shift_ptr, int *fin,
 
   if (in == last) {
     *res = n;
-    return (ssize_t)(in - start);
+    return (nghttp2_ssize)(in - start);
   }
 
   *res = n;
   *fin = 1;
-  return (ssize_t)(in + 1 - start);
+  return (nghttp2_ssize)(in + 1 - start);
 }
 
 static int emit_table_size(nghttp2_bufs *bufs, size_t table_size) {
@@ -1164,7 +1165,7 @@ static int add_hd_table_incremental(nghttp2_hd_context *context,
 }
 
 typedef struct {
-  ssize_t index;
+  nghttp2_ssize index;
   /* Nonzero if both name and value are matched. */
   int name_value_match;
 } search_result;
@@ -1213,8 +1214,8 @@ static search_result search_hd_table(nghttp2_hd_context *context,
     return res;
   }
 
-  res.index =
-      (ssize_t)(context->next_seq - 1 - ent->seq + NGHTTP2_STATIC_TABLE_LENGTH);
+  res.index = (nghttp2_ssize)(context->next_seq - 1 - ent->seq +
+                              NGHTTP2_STATIC_TABLE_LENGTH);
   res.name_value_match = exact_match;
 
   return res;
@@ -1343,7 +1344,7 @@ static int deflate_nv(nghttp2_hd_deflater *deflater, nghttp2_bufs *bufs,
                       const nghttp2_nv *nv) {
   int rv;
   search_result res;
-  ssize_t idx;
+  nghttp2_ssize idx;
   int indexing_mode;
   int32_t token;
   nghttp2_mem *mem;
@@ -1379,7 +1380,7 @@ static int deflate_nv(nghttp2_hd_deflater *deflater, nghttp2_bufs *bufs,
 
   if (res.name_value_match) {
 
-    DEBUGF("deflatehd: name/value match index=%zd\n", idx);
+    DEBUGF("deflatehd: name/value match index=%td\n", idx);
 
     rv = emit_indexed_block(bufs, (size_t)idx);
     if (rv != 0) {
@@ -1390,7 +1391,7 @@ static int deflate_nv(nghttp2_hd_deflater *deflater, nghttp2_bufs *bufs,
   }
 
   if (res.index != -1) {
-    DEBUGF("deflatehd: name match index=%zd\n", res.index);
+    DEBUGF("deflatehd: name match index=%td\n", res.index);
   }
 
   if (indexing_mode == NGHTTP2_HD_WITH_INDEXING) {
@@ -1491,6 +1492,12 @@ fail:
 ssize_t nghttp2_hd_deflate_hd(nghttp2_hd_deflater *deflater, uint8_t *buf,
                               size_t buflen, const nghttp2_nv *nv,
                               size_t nvlen) {
+  return (ssize_t)nghttp2_hd_deflate_hd2(deflater, buf, buflen, nv, nvlen);
+}
+
+nghttp2_ssize nghttp2_hd_deflate_hd2(nghttp2_hd_deflater *deflater,
+                                     uint8_t *buf, size_t buflen,
+                                     const nghttp2_nv *nv, size_t nvlen) {
   nghttp2_bufs bufs;
   int rv;
   nghttp2_mem *mem;
@@ -1517,12 +1524,18 @@ ssize_t nghttp2_hd_deflate_hd(nghttp2_hd_deflater *deflater, uint8_t *buf,
     return rv;
   }
 
-  return (ssize_t)buflen;
+  return (nghttp2_ssize)buflen;
 }
 
 ssize_t nghttp2_hd_deflate_hd_vec(nghttp2_hd_deflater *deflater,
                                   const nghttp2_vec *vec, size_t veclen,
                                   const nghttp2_nv *nv, size_t nvlen) {
+  return (ssize_t)nghttp2_hd_deflate_hd_vec2(deflater, vec, veclen, nv, nvlen);
+}
+
+nghttp2_ssize nghttp2_hd_deflate_hd_vec2(nghttp2_hd_deflater *deflater,
+                                         const nghttp2_vec *vec, size_t veclen,
+                                         const nghttp2_nv *nv, size_t nvlen) {
   nghttp2_bufs bufs;
   int rv;
   nghttp2_mem *mem;
@@ -1550,7 +1563,7 @@ ssize_t nghttp2_hd_deflate_hd_vec(nghttp2_hd_deflater *deflater,
     return rv;
   }
 
-  return (ssize_t)buflen;
+  return (nghttp2_ssize)buflen;
 }
 
 size_t nghttp2_hd_deflate_bound(nghttp2_hd_deflater *deflater,
@@ -1643,10 +1656,11 @@ static void hd_inflate_set_huffman_encoded(nghttp2_hd_inflater *inflater,
  * NGHTTP2_ERR_HEADER_COMP
  *   Integer decoding failed
  */
-static ssize_t hd_inflate_read_len(nghttp2_hd_inflater *inflater, int *rfin,
-                                   const uint8_t *in, const uint8_t *last,
-                                   size_t prefix, size_t maxlen) {
-  ssize_t rv;
+static nghttp2_ssize hd_inflate_read_len(nghttp2_hd_inflater *inflater,
+                                         int *rfin, const uint8_t *in,
+                                         const uint8_t *last, size_t prefix,
+                                         size_t maxlen) {
+  nghttp2_ssize rv;
   uint32_t out;
 
   *rfin = 0;
@@ -1684,10 +1698,10 @@ static ssize_t hd_inflate_read_len(nghttp2_hd_inflater *inflater, int *rfin,
  * NGHTTP2_ERR_HEADER_COMP
  *   Huffman decoding failed
  */
-static ssize_t hd_inflate_read_huff(nghttp2_hd_inflater *inflater,
-                                    nghttp2_buf *buf, const uint8_t *in,
-                                    const uint8_t *last) {
-  ssize_t readlen;
+static nghttp2_ssize hd_inflate_read_huff(nghttp2_hd_inflater *inflater,
+                                          nghttp2_buf *buf, const uint8_t *in,
+                                          const uint8_t *last) {
+  nghttp2_ssize readlen;
   int fin = 0;
   if ((size_t)(last - in) >= inflater->left) {
     last = in + inflater->left;
@@ -1721,14 +1735,15 @@ static ssize_t hd_inflate_read_huff(nghttp2_hd_inflater *inflater,
  * NGHTTP2_ERR_HEADER_COMP
  *   Header decompression failed
  */
-static ssize_t hd_inflate_read(nghttp2_hd_inflater *inflater, nghttp2_buf *buf,
-                               const uint8_t *in, const uint8_t *last) {
+static nghttp2_ssize hd_inflate_read(nghttp2_hd_inflater *inflater,
+                                     nghttp2_buf *buf, const uint8_t *in,
+                                     const uint8_t *last) {
   size_t len = nghttp2_min((size_t)(last - in), inflater->left);
 
   buf->last = nghttp2_cpymem(buf->last, in, len);
 
   inflater->left -= len;
-  return (ssize_t)len;
+  return (nghttp2_ssize)len;
 }
 
 /*
@@ -1843,7 +1858,15 @@ ssize_t nghttp2_hd_inflate_hd(nghttp2_hd_inflater *inflater, nghttp2_nv *nv_out,
 ssize_t nghttp2_hd_inflate_hd2(nghttp2_hd_inflater *inflater,
                                nghttp2_nv *nv_out, int *inflate_flags,
                                const uint8_t *in, size_t inlen, int in_final) {
-  ssize_t rv;
+  return (nghttp2_ssize)nghttp2_hd_inflate_hd3(inflater, nv_out, inflate_flags,
+                                               in, inlen, in_final);
+}
+
+nghttp2_ssize nghttp2_hd_inflate_hd3(nghttp2_hd_inflater *inflater,
+                                     nghttp2_nv *nv_out, int *inflate_flags,
+                                     const uint8_t *in, size_t inlen,
+                                     int in_final) {
+  nghttp2_ssize rv;
   nghttp2_hd_nv hd_nv;
 
   rv = nghttp2_hd_inflate_hd_nv(inflater, &hd_nv, inflate_flags, in, inlen,
@@ -1866,11 +1889,11 @@ ssize_t nghttp2_hd_inflate_hd2(nghttp2_hd_inflater *inflater,
   return rv;
 }
 
-ssize_t nghttp2_hd_inflate_hd_nv(nghttp2_hd_inflater *inflater,
-                                 nghttp2_hd_nv *nv_out, int *inflate_flags,
-                                 const uint8_t *in, size_t inlen,
-                                 int in_final) {
-  ssize_t rv = 0;
+nghttp2_ssize nghttp2_hd_inflate_hd_nv(nghttp2_hd_inflater *inflater,
+                                       nghttp2_hd_nv *nv_out,
+                                       int *inflate_flags, const uint8_t *in,
+                                       size_t inlen, int in_final) {
+  nghttp2_ssize rv = 0;
   const uint8_t *first = in;
   const uint8_t *last = in + inlen;
   int rfin = 0;
@@ -1992,7 +2015,7 @@ ssize_t nghttp2_hd_inflate_hd_nv(nghttp2_hd_inflater *inflater,
 
         inflater->state = NGHTTP2_HD_STATE_OPCODE;
         *inflate_flags |= NGHTTP2_HD_INFLATE_EMIT;
-        return (ssize_t)(in - first);
+        return (nghttp2_ssize)(in - first);
       } else {
         inflater->index = inflater->left;
         --inflater->index;
@@ -2050,7 +2073,7 @@ ssize_t nghttp2_hd_inflate_hd_nv(nghttp2_hd_inflater *inflater,
 
       in += rv;
 
-      DEBUGF("inflatehd: %zd bytes read\n", rv);
+      DEBUGF("inflatehd: %td bytes read\n", rv);
 
       if (inflater->left) {
         DEBUGF("inflatehd: still %zu bytes to go\n", inflater->left);
@@ -2072,7 +2095,7 @@ ssize_t nghttp2_hd_inflate_hd_nv(nghttp2_hd_inflater *inflater,
 
       in += rv;
 
-      DEBUGF("inflatehd: %zd bytes read\n", rv);
+      DEBUGF("inflatehd: %td bytes read\n", rv);
       if (inflater->left) {
         DEBUGF("inflatehd: still %zu bytes to go\n", inflater->left);
 
@@ -2138,7 +2161,7 @@ ssize_t nghttp2_hd_inflate_hd_nv(nghttp2_hd_inflater *inflater,
 
       in += rv;
 
-      DEBUGF("inflatehd: %zd bytes read\n", rv);
+      DEBUGF("inflatehd: %td bytes read\n", rv);
 
       if (inflater->left) {
         DEBUGF("inflatehd: still %zu bytes to go\n", inflater->left);
@@ -2162,18 +2185,18 @@ ssize_t nghttp2_hd_inflate_hd_nv(nghttp2_hd_inflater *inflater,
       inflater->state = NGHTTP2_HD_STATE_OPCODE;
       *inflate_flags |= NGHTTP2_HD_INFLATE_EMIT;
 
-      return (ssize_t)(in - first);
+      return (nghttp2_ssize)(in - first);
     case NGHTTP2_HD_STATE_READ_VALUE:
       rv = hd_inflate_read(inflater, &inflater->valuebuf, in, last);
       if (rv < 0) {
-        DEBUGF("inflatehd: value read failure %zd: %s\n", rv,
+        DEBUGF("inflatehd: value read failure %td: %s\n", rv,
                nghttp2_strerror((int)rv));
         goto fail;
       }
 
       in += rv;
 
-      DEBUGF("inflatehd: %zd bytes read\n", rv);
+      DEBUGF("inflatehd: %td bytes read\n", rv);
 
       if (inflater->left) {
         DEBUGF("inflatehd: still %zu bytes to go\n", inflater->left);
@@ -2196,7 +2219,7 @@ ssize_t nghttp2_hd_inflate_hd_nv(nghttp2_hd_inflater *inflater,
       inflater->state = NGHTTP2_HD_STATE_OPCODE;
       *inflate_flags |= NGHTTP2_HD_INFLATE_EMIT;
 
-      return (ssize_t)(in - first);
+      return (nghttp2_ssize)(in - first);
     }
   }
 
@@ -2216,7 +2239,7 @@ ssize_t nghttp2_hd_inflate_hd_nv(nghttp2_hd_inflater *inflater,
     }
     *inflate_flags |= NGHTTP2_HD_INFLATE_FINAL;
   }
-  return (ssize_t)(in - first);
+  return (nghttp2_ssize)(in - first);
 
 almost_ok:
   if (in_final) {
@@ -2226,10 +2249,10 @@ almost_ok:
 
     goto fail;
   }
-  return (ssize_t)(in - first);
+  return (nghttp2_ssize)(in - first);
 
 fail:
-  DEBUGF("inflatehd: error return %zd\n", rv);
+  DEBUGF("inflatehd: error return %td\n", rv);
 
   inflater->ctx.bad = 1;
   return rv;
@@ -2297,9 +2320,10 @@ int nghttp2_hd_emit_table_size(nghttp2_bufs *bufs, size_t table_size) {
   return emit_table_size(bufs, table_size);
 }
 
-ssize_t nghttp2_hd_decode_length(uint32_t *res, size_t *shift_ptr, int *fin,
-                                 uint32_t initial, size_t shift, uint8_t *in,
-                                 uint8_t *last, size_t prefix) {
+nghttp2_ssize nghttp2_hd_decode_length(uint32_t *res, size_t *shift_ptr,
+                                       int *fin, uint32_t initial, size_t shift,
+                                       uint8_t *in, uint8_t *last,
+                                       size_t prefix) {
   return decode_length(res, shift_ptr, fin, initial, shift, in, last, prefix);
 }
 
diff --git a/contrib/libs/nghttp2/lib/nghttp2_hd.h b/contrib/libs/nghttp2/lib/nghttp2_hd.h
index 6de0052aae..38a31a83c3 100644
--- a/contrib/libs/nghttp2/lib/nghttp2_hd.h
+++ b/contrib/libs/nghttp2/lib/nghttp2_hd.h
@@ -357,9 +357,10 @@ void nghttp2_hd_inflate_free(nghttp2_hd_inflater *inflater);
  * that return values and semantics are the same as
  * nghttp2_hd_inflate_hd().
  */
-ssize_t nghttp2_hd_inflate_hd_nv(nghttp2_hd_inflater *inflater,
-                                 nghttp2_hd_nv *nv_out, int *inflate_flags,
-                                 const uint8_t *in, size_t inlen, int in_final);
+nghttp2_ssize nghttp2_hd_inflate_hd_nv(nghttp2_hd_inflater *inflater,
+                                       nghttp2_hd_nv *nv_out,
+                                       int *inflate_flags, const uint8_t *in,
+                                       size_t inlen, int in_final);
 
 /* For unittesting purpose */
 int nghttp2_hd_emit_indname_block(nghttp2_bufs *bufs, size_t index,
@@ -376,9 +377,10 @@ int nghttp2_hd_emit_table_size(nghttp2_bufs *bufs, size_t table_size);
 nghttp2_hd_nv nghttp2_hd_table_get(nghttp2_hd_context *context, size_t index);
 
 /* For unittesting purpose */
-ssize_t nghttp2_hd_decode_length(uint32_t *res, size_t *shift_ptr, int *fin,
-                                 uint32_t initial, size_t shift, uint8_t *in,
-                                 uint8_t *last, size_t prefix);
+nghttp2_ssize nghttp2_hd_decode_length(uint32_t *res, size_t *shift_ptr,
+                                       int *fin, uint32_t initial, size_t shift,
+                                       uint8_t *in, uint8_t *last,
+                                       size_t prefix);
 
 /* Huffman encoding/decoding functions */
 
@@ -427,9 +429,9 @@ void nghttp2_hd_huff_decode_context_init(nghttp2_hd_huff_decode_context *ctx);
  * NGHTTP2_ERR_HEADER_COMP
  *     Decoding process has failed.
  */
-ssize_t nghttp2_hd_huff_decode(nghttp2_hd_huff_decode_context *ctx,
-                               nghttp2_buf *buf, const uint8_t *src,
-                               size_t srclen, int fin);
+nghttp2_ssize nghttp2_hd_huff_decode(nghttp2_hd_huff_decode_context *ctx,
+                                     nghttp2_buf *buf, const uint8_t *src,
+                                     size_t srclen, int fin);
 
 /*
  * nghttp2_hd_huff_decode_failure_state returns nonzero if |ctx|
diff --git a/contrib/libs/nghttp2/lib/nghttp2_hd_huffman.c b/contrib/libs/nghttp2/lib/nghttp2_hd_huffman.c
index ac90f49c44..959053f774 100644
--- a/contrib/libs/nghttp2/lib/nghttp2_hd_huffman.c
+++ b/contrib/libs/nghttp2/lib/nghttp2_hd_huffman.c
@@ -107,9 +107,9 @@ void nghttp2_hd_huff_decode_context_init(nghttp2_hd_huff_decode_context *ctx) {
   ctx->fstate = NGHTTP2_HUFF_ACCEPTED;
 }
 
-ssize_t nghttp2_hd_huff_decode(nghttp2_hd_huff_decode_context *ctx,
-                               nghttp2_buf *buf, const uint8_t *src,
-                               size_t srclen, int final) {
+nghttp2_ssize nghttp2_hd_huff_decode(nghttp2_hd_huff_decode_context *ctx,
+                                     nghttp2_buf *buf, const uint8_t *src,
+                                     size_t srclen, int final) {
   const uint8_t *end = src + srclen;
   nghttp2_huff_decode node = {ctx->fstate, 0};
   const nghttp2_huff_decode *t = &node;
@@ -136,7 +136,7 @@ ssize_t nghttp2_hd_huff_decode(nghttp2_hd_huff_decode_context *ctx,
     return NGHTTP2_ERR_HEADER_COMP;
   }
 
-  return (ssize_t)srclen;
+  return (nghttp2_ssize)srclen;
 }
 
 int nghttp2_hd_huff_decode_failure_state(nghttp2_hd_huff_decode_context *ctx) {
diff --git a/contrib/libs/nghttp2/lib/nghttp2_outbound_item.c b/contrib/libs/nghttp2/lib/nghttp2_outbound_item.c
index 2a3041db19..a9e9f7693e 100644
--- a/contrib/libs/nghttp2/lib/nghttp2_outbound_item.c
+++ b/contrib/libs/nghttp2/lib/nghttp2_outbound_item.c
@@ -27,6 +27,32 @@
 #include <assert.h>
 #include <string.h>
 
+nghttp2_data_provider_wrap *
+nghttp2_data_provider_wrap_v1(nghttp2_data_provider_wrap *dpw,
+                              const nghttp2_data_provider *data_prd) {
+  if (!data_prd) {
+    return NULL;
+  }
+
+  dpw->version = NGHTTP2_DATA_PROVIDER_V1;
+  dpw->data_prd.v1 = *data_prd;
+
+  return dpw;
+}
+
+nghttp2_data_provider_wrap *
+nghttp2_data_provider_wrap_v2(nghttp2_data_provider_wrap *dpw,
+                              const nghttp2_data_provider2 *data_prd) {
+  if (!data_prd) {
+    return NULL;
+  }
+
+  dpw->version = NGHTTP2_DATA_PROVIDER_V2;
+  dpw->data_prd.v2 = *data_prd;
+
+  return dpw;
+}
+
 void nghttp2_outbound_item_init(nghttp2_outbound_item *item) {
   item->cycle = 0;
   item->qnext = NULL;
diff --git a/contrib/libs/nghttp2/lib/nghttp2_outbound_item.h b/contrib/libs/nghttp2/lib/nghttp2_outbound_item.h
index bd4611b551..4e91750088 100644
--- a/contrib/libs/nghttp2/lib/nghttp2_outbound_item.h
+++ b/contrib/libs/nghttp2/lib/nghttp2_outbound_item.h
@@ -33,9 +33,32 @@
 #include "nghttp2_frame.h"
 #include "nghttp2_mem.h"
 
+#define NGHTTP2_DATA_PROVIDER_V1 1
+#define NGHTTP2_DATA_PROVIDER_V2 2
+
+typedef struct nghttp2_data_provider_wrap {
+  int version;
+  union {
+    struct {
+      nghttp2_data_source source;
+      void *read_callback;
+    };
+    nghttp2_data_provider v1;
+    nghttp2_data_provider2 v2;
+  } data_prd;
+} nghttp2_data_provider_wrap;
+
+nghttp2_data_provider_wrap *
+nghttp2_data_provider_wrap_v1(nghttp2_data_provider_wrap *dpw,
+                              const nghttp2_data_provider *data_prd);
+
+nghttp2_data_provider_wrap *
+nghttp2_data_provider_wrap_v2(nghttp2_data_provider_wrap *dpw,
+                              const nghttp2_data_provider2 *data_prd);
+
 /* struct used for HEADERS and PUSH_PROMISE frame */
 typedef struct {
-  nghttp2_data_provider data_prd;
+  nghttp2_data_provider_wrap dpw;
   void *stream_user_data;
   /* error code when request HEADERS is canceled by RST_STREAM while
      it is in queue. */
@@ -50,7 +73,7 @@ typedef struct {
   /**
    * The data to be sent for this DATA frame.
    */
-  nghttp2_data_provider data_prd;
+  nghttp2_data_provider_wrap dpw;
   /**
    * The flags of DATA frame.  We use separate flags here and
    * nghttp2_data frame.  The latter contains flags actually sent to
diff --git a/contrib/libs/nghttp2/lib/nghttp2_session.c b/contrib/libs/nghttp2/lib/nghttp2_session.c
index ce21caf9d7..226cdd59e8 100644
--- a/contrib/libs/nghttp2/lib/nghttp2_session.c
+++ b/contrib/libs/nghttp2/lib/nghttp2_session.c
@@ -39,6 +39,7 @@
 #include "nghttp2_extpri.h"
 #include "nghttp2_time.h"
 #include "nghttp2_debug.h"
+#include "nghttp2_submit.h"
 
 /*
  * Returns non-zero if the number of outgoing opened streams is larger
@@ -2103,10 +2104,9 @@ static int session_predicate_priority_update_send(nghttp2_session *session,
 
 /* Take into account settings max frame size and both connection-level
    flow control here */
-static ssize_t
-nghttp2_session_enforce_flow_control_limits(nghttp2_session *session,
-                                            nghttp2_stream *stream,
-                                            ssize_t requested_window_size) {
+static nghttp2_ssize nghttp2_session_enforce_flow_control_limits(
+    nghttp2_session *session, nghttp2_stream *stream,
+    nghttp2_ssize requested_window_size) {
   DEBUGF("send: remote windowsize connection=%d, remote maxframsize=%u, "
          "stream(id %d)=%d\n",
          session->remote_window_size, session->remote_settings.max_frame_size,
@@ -2126,12 +2126,12 @@ nghttp2_session_enforce_flow_control_limits(nghttp2_session *session,
  */
 static size_t nghttp2_session_next_data_read(nghttp2_session *session,
                                              nghttp2_stream *stream) {
-  ssize_t window_size;
+  nghttp2_ssize window_size;
 
   window_size = nghttp2_session_enforce_flow_control_limits(
       session, stream, NGHTTP2_DATA_PAYLOADLEN);
 
-  DEBUGF("send: available window=%zd\n", window_size);
+  DEBUGF("send: available window=%td\n", window_size);
 
   return window_size > 0 ? (size_t)window_size : 0;
 }
@@ -2186,29 +2186,33 @@ static int nghttp2_session_predicate_data_send(nghttp2_session *session,
   return NGHTTP2_ERR_INVALID_STREAM_STATE;
 }
 
-static ssize_t session_call_select_padding(nghttp2_session *session,
-                                           const nghttp2_frame *frame,
-                                           size_t max_payloadlen) {
-  ssize_t rv;
+static nghttp2_ssize session_call_select_padding(nghttp2_session *session,
+                                                 const nghttp2_frame *frame,
+                                                 size_t max_payloadlen) {
+  nghttp2_ssize rv;
+  size_t max_paddedlen;
 
-  if (frame->hd.length >= max_payloadlen) {
-    return (ssize_t)frame->hd.length;
+  if (frame->hd.length >= max_payloadlen ||
+      (!session->callbacks.select_padding_callback2 &&
+       !session->callbacks.select_padding_callback)) {
+    return (nghttp2_ssize)frame->hd.length;
   }
 
-  if (session->callbacks.select_padding_callback) {
-    size_t max_paddedlen;
-
-    max_paddedlen =
-        nghttp2_min(frame->hd.length + NGHTTP2_MAX_PADLEN, max_payloadlen);
+  max_paddedlen =
+      nghttp2_min(frame->hd.length + NGHTTP2_MAX_PADLEN, max_payloadlen);
 
-    rv = session->callbacks.select_padding_callback(
+  if (session->callbacks.select_padding_callback2) {
+    rv = session->callbacks.select_padding_callback2(
         session, frame, max_paddedlen, session->user_data);
-    if (rv < (ssize_t)frame->hd.length || rv > (ssize_t)max_paddedlen) {
-      return NGHTTP2_ERR_CALLBACK_FAILURE;
-    }
-    return rv;
+  } else {
+    rv = (nghttp2_ssize)session->callbacks.select_padding_callback(
+        session, frame, max_paddedlen, session->user_data);
+  }
+  if (rv < (nghttp2_ssize)frame->hd.length ||
+      rv > (nghttp2_ssize)max_paddedlen) {
+    return NGHTTP2_ERR_CALLBACK_FAILURE;
   }
-  return (ssize_t)frame->hd.length;
+  return rv;
 }
 
 /* Add padding to HEADERS or PUSH_PROMISE. We use
@@ -2216,7 +2220,7 @@ static ssize_t session_call_select_padding(nghttp2_session *session,
    frame->push_promise has also padlen in the same position. */
 static int session_headers_add_pad(nghttp2_session *session,
                                    nghttp2_frame *frame) {
-  ssize_t padded_payloadlen;
+  nghttp2_ssize padded_payloadlen;
   nghttp2_active_outbound_item *aob;
   nghttp2_bufs *framebufs;
   size_t padlen;
@@ -2237,7 +2241,7 @@ static int session_headers_add_pad(nghttp2_session *session,
 
   padlen = (size_t)padded_payloadlen - frame->hd.length;
 
-  DEBUGF("send: padding selected: payloadlen=%zd, padlen=%zu\n",
+  DEBUGF("send: padding selected: payloadlen=%td, padlen=%zu\n",
          padded_payloadlen, padlen);
 
   nghttp2_frame_add_pad(framebufs, &frame->hd, padlen, 0);
@@ -2257,18 +2261,24 @@ static size_t session_estimate_headers_payload(nghttp2_session *session,
 
 static int session_pack_extension(nghttp2_session *session, nghttp2_bufs *bufs,
                                   nghttp2_frame *frame) {
-  ssize_t rv;
+  nghttp2_ssize rv;
   nghttp2_buf *buf;
   size_t buflen;
   size_t framelen;
 
-  assert(session->callbacks.pack_extension_callback);
+  assert(session->callbacks.pack_extension_callback2 ||
+         session->callbacks.pack_extension_callback);
 
   buf = &bufs->head->buf;
   buflen = nghttp2_min(nghttp2_buf_avail(buf), NGHTTP2_MAX_PAYLOADLEN);
 
-  rv = session->callbacks.pack_extension_callback(session, buf->last, buflen,
-                                                  frame, session->user_data);
+  if (session->callbacks.pack_extension_callback2) {
+    rv = session->callbacks.pack_extension_callback2(session, buf->last, buflen,
+                                                     frame, session->user_data);
+  } else {
+    rv = (nghttp2_ssize)session->callbacks.pack_extension_callback(
+        session, buf->last, buflen, frame, session->user_data);
+  }
   if (rv == NGHTTP2_ERR_CANCEL) {
     return (int)rv;
   }
@@ -2451,7 +2461,7 @@ static int session_prep_frame(nghttp2_session *session,
       return rv;
     }
 
-    DEBUGF("send: before padding, HEADERS serialized in %zd bytes\n",
+    DEBUGF("send: before padding, HEADERS serialized in %zu bytes\n",
            nghttp2_bufs_len(&session->aob.framebufs));
 
     rv = session_headers_add_pad(session, frame);
@@ -2460,7 +2470,7 @@ static int session_prep_frame(nghttp2_session *session,
       return rv;
     }
 
-    DEBUGF("send: HEADERS finally serialized in %zd bytes\n",
+    DEBUGF("send: HEADERS finally serialized in %zu bytes\n",
            nghttp2_bufs_len(&session->aob.framebufs));
 
     if (frame->headers.cat == NGHTTP2_HCAT_REQUEST) {
@@ -2877,7 +2887,7 @@ static int session_after_frame_sent1(nghttp2_session *session) {
 
       /* Call on_frame_send_callback after
          nghttp2_stream_detach_item(), so that application can issue
-         nghttp2_submit_data() in the callback. */
+         nghttp2_submit_data2() in the callback. */
       if (session->callbacks.on_frame_send_callback) {
         rv = session_call_on_frame_send(session, frame);
         if (nghttp2_is_fatal(rv)) {
@@ -2949,15 +2959,17 @@ static int session_after_frame_sent1(nghttp2_session *session) {
       }
       /* We assume aux_data is a pointer to nghttp2_headers_aux_data */
       aux_data = &item->aux_data.headers;
-      if (aux_data->data_prd.read_callback) {
-        /* nghttp2_submit_data() makes a copy of aux_data->data_prd */
-        rv = nghttp2_submit_data(session, NGHTTP2_FLAG_END_STREAM,
-                                 frame->hd.stream_id, &aux_data->data_prd);
+      if (aux_data->dpw.data_prd.read_callback) {
+        /* nghttp2_submit_data_shared() makes a copy of
+           aux_data->dpw */
+        rv = nghttp2_submit_data_shared(session, NGHTTP2_FLAG_END_STREAM,
+                                        frame->hd.stream_id, &aux_data->dpw);
         if (nghttp2_is_fatal(rv)) {
           return rv;
         }
-        /* TODO nghttp2_submit_data() may fail if stream has already
-           DATA frame item.  We might have to handle it here. */
+        /* TODO nghttp2_submit_data_shared() may fail if stream has
+           already DATA frame item.  We might have to handle it
+           here. */
       }
       return 0;
     }
@@ -2978,14 +2990,15 @@ static int session_after_frame_sent1(nghttp2_session *session) {
       }
       /* We assume aux_data is a pointer to nghttp2_headers_aux_data */
       aux_data = &item->aux_data.headers;
-      if (aux_data->data_prd.read_callback) {
-        rv = nghttp2_submit_data(session, NGHTTP2_FLAG_END_STREAM,
-                                 frame->hd.stream_id, &aux_data->data_prd);
+      if (aux_data->dpw.data_prd.read_callback) {
+        rv = nghttp2_submit_data_shared(session, NGHTTP2_FLAG_END_STREAM,
+                                        frame->hd.stream_id, &aux_data->dpw);
         if (nghttp2_is_fatal(rv)) {
           return rv;
         }
-        /* TODO nghttp2_submit_data() may fail if stream has already
-           DATA frame item.  We might have to handle it here. */
+        /* TODO nghttp2_submit_data_shared() may fail if stream has
+           already DATA frame item.  We might have to handle it
+           here. */
       }
       return 0;
     default:
@@ -3144,7 +3157,7 @@ static void session_after_frame_sent2(nghttp2_session *session) {
   aux_data = &item->aux_data.data;
 
   /* On EOF, we have already detached data.  Please note that
-     application may issue nghttp2_submit_data() in
+     application may issue nghttp2_submit_data2() in
      on_frame_send_callback (call from session_after_frame_sent1),
      which attach data to stream.  We don't want to detach it. */
   if (aux_data->eof) {
@@ -3191,7 +3204,7 @@ static int session_call_send_data(nghttp2_session *session,
   aux_data = &item->aux_data.data;
 
   rv = session->callbacks.send_data_callback(session, frame, buf->pos, length,
-                                             &aux_data->data_prd.source,
+                                             &aux_data->dpw.data_prd.source,
                                              session->user_data);
 
   switch (rv) {
@@ -3205,9 +3218,9 @@ static int session_call_send_data(nghttp2_session *session,
   }
 }
 
-static ssize_t nghttp2_session_mem_send_internal(nghttp2_session *session,
-                                                 const uint8_t **data_ptr,
-                                                 int fast_cb) {
+static nghttp2_ssize nghttp2_session_mem_send_internal(nghttp2_session *session,
+                                                       const uint8_t **data_ptr,
+                                                       int fast_cb) {
   int rv;
   nghttp2_active_outbound_item *aob;
   nghttp2_bufs *framebufs;
@@ -3385,7 +3398,7 @@ static ssize_t nghttp2_session_mem_send_internal(nghttp2_session *session,
         }
       }
 
-      DEBUGF("send: start transmitting frame type=%u, length=%zd\n",
+      DEBUGF("send: start transmitting frame type=%u, length=%td\n",
              framebufs->cur->buf.pos[3],
              framebufs->cur->buf.last - framebufs->cur->buf.pos);
 
@@ -3425,7 +3438,7 @@ static ssize_t nghttp2_session_mem_send_internal(nghttp2_session *session,
          everything, we will adjust it. */
       buf->pos += datalen;
 
-      return (ssize_t)datalen;
+      return (nghttp2_ssize)datalen;
     }
     case NGHTTP2_OB_SEND_NO_COPY: {
       nghttp2_stream *stream;
@@ -3502,7 +3515,7 @@ static ssize_t nghttp2_session_mem_send_internal(nghttp2_session *session,
 
       buf->pos += datalen;
 
-      return (ssize_t)datalen;
+      return (nghttp2_ssize)datalen;
     }
     }
   }
@@ -3510,8 +3523,13 @@ static ssize_t nghttp2_session_mem_send_internal(nghttp2_session *session,
 
 ssize_t nghttp2_session_mem_send(nghttp2_session *session,
                                  const uint8_t **data_ptr) {
+  return (ssize_t)nghttp2_session_mem_send2(session, data_ptr);
+}
+
+nghttp2_ssize nghttp2_session_mem_send2(nghttp2_session *session,
+                                        const uint8_t **data_ptr) {
   int rv;
-  ssize_t len;
+  nghttp2_ssize len;
 
   *data_ptr = NULL;
 
@@ -3528,7 +3546,7 @@ ssize_t nghttp2_session_mem_send(nghttp2_session *session,
     rv = session_after_frame_sent1(session);
     if (rv < 0) {
       assert(nghttp2_is_fatal(rv));
-      return (ssize_t)rv;
+      return (nghttp2_ssize)rv;
     }
   }
 
@@ -3537,8 +3555,8 @@ ssize_t nghttp2_session_mem_send(nghttp2_session *session,
 
 int nghttp2_session_send(nghttp2_session *session) {
   const uint8_t *data = NULL;
-  ssize_t datalen;
-  ssize_t sentlen;
+  nghttp2_ssize datalen;
+  nghttp2_ssize sentlen;
   nghttp2_bufs *framebufs;
 
   framebufs = &session->aob.framebufs;
@@ -3548,8 +3566,13 @@ int nghttp2_session_send(nghttp2_session *session) {
     if (datalen <= 0) {
       return (int)datalen;
     }
-    sentlen = session->callbacks.send_callback(session, data, (size_t)datalen,
-                                               0, session->user_data);
+    if (session->callbacks.send_callback2) {
+      sentlen = session->callbacks.send_callback2(
+          session, data, (size_t)datalen, 0, session->user_data);
+    } else {
+      sentlen = (nghttp2_ssize)session->callbacks.send_callback(
+          session, data, (size_t)datalen, 0, session->user_data);
+    }
     if (sentlen < 0) {
       if (sentlen == NGHTTP2_ERR_WOULDBLOCK) {
         /* Transmission canceled. Rewind the offset */
@@ -3564,11 +3587,17 @@ int nghttp2_session_send(nghttp2_session *session) {
   }
 }
 
-static ssize_t session_recv(nghttp2_session *session, uint8_t *buf,
-                            size_t len) {
-  ssize_t rv;
-  rv = session->callbacks.recv_callback(session, buf, len, 0,
-                                        session->user_data);
+static nghttp2_ssize session_recv(nghttp2_session *session, uint8_t *buf,
+                                  size_t len) {
+  nghttp2_ssize rv;
+
+  if (session->callbacks.recv_callback2) {
+    rv = session->callbacks.recv_callback2(session, buf, len, 0,
+                                           session->user_data);
+  } else {
+    rv = (nghttp2_ssize)session->callbacks.recv_callback(session, buf, len, 0,
+                                                         session->user_data);
+  }
   if (rv > 0) {
     if ((size_t)rv > len) {
       return NGHTTP2_ERR_CALLBACK_FAILURE;
@@ -3870,7 +3899,7 @@ static int session_inflate_handle_invalid_connection(nghttp2_session *session,
 static int inflate_header_block(nghttp2_session *session, nghttp2_frame *frame,
                                 size_t *readlen_ptr, uint8_t *in, size_t inlen,
                                 int final, int call_header_cb) {
-  ssize_t proclen;
+  nghttp2_ssize proclen;
   int rv;
   int inflate_flags;
   nghttp2_hd_nv nv;
@@ -3923,7 +3952,7 @@ static int inflate_header_block(nghttp2_session *session, nghttp2_frame *frame,
     inlen -= (size_t)proclen;
     *readlen_ptr += (size_t)proclen;
 
-    DEBUGF("recv: proclen=%zd\n", proclen);
+    DEBUGF("recv: proclen=%td\n", proclen);
 
     if (call_header_cb && (inflate_flags & NGHTTP2_HD_INFLATE_EMIT)) {
       rv = 0;
@@ -5763,7 +5792,7 @@ static int inbound_frame_handle_pad(nghttp2_inbound_frame *iframe,
  * Computes number of padding based on flags. This function returns
  * the calculated length if it succeeds, or -1.
  */
-static ssize_t inbound_frame_compute_pad(nghttp2_inbound_frame *iframe) {
+static nghttp2_ssize inbound_frame_compute_pad(nghttp2_inbound_frame *iframe) {
   size_t padlen;
 
   /* 1 for Pad Length field */
@@ -5778,7 +5807,7 @@ static ssize_t inbound_frame_compute_pad(nghttp2_inbound_frame *iframe) {
 
   iframe->padlen = padlen;
 
-  return (ssize_t)padlen;
+  return (nghttp2_ssize)padlen;
 }
 
 /*
@@ -5787,9 +5816,9 @@ static ssize_t inbound_frame_compute_pad(nghttp2_inbound_frame *iframe) {
  * |payloadleft| does not include |readlen|. If padding was started
  * strictly before this data chunk, this function returns -1.
  */
-static ssize_t inbound_frame_effective_readlen(nghttp2_inbound_frame *iframe,
-                                               size_t payloadleft,
-                                               size_t readlen) {
+static nghttp2_ssize
+inbound_frame_effective_readlen(nghttp2_inbound_frame *iframe,
+                                size_t payloadleft, size_t readlen) {
   size_t trail_padlen =
       nghttp2_frame_trail_padlen(&iframe->frame, iframe->padlen);
 
@@ -5799,19 +5828,24 @@ static ssize_t inbound_frame_effective_readlen(nghttp2_inbound_frame *iframe,
     if (readlen < padlen) {
       return -1;
     }
-    return (ssize_t)(readlen - padlen);
+    return (nghttp2_ssize)(readlen - padlen);
   }
-  return (ssize_t)(readlen);
+  return (nghttp2_ssize)(readlen);
 }
 
 static const uint8_t static_in[] = {0};
 
 ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
                                  size_t inlen) {
+  return (ssize_t)nghttp2_session_mem_recv2(session, in, inlen);
+}
+
+nghttp2_ssize nghttp2_session_mem_recv2(nghttp2_session *session,
+                                        const uint8_t *in, size_t inlen) {
   const uint8_t *first, *last;
   nghttp2_inbound_frame *iframe = &session->iframe;
   size_t readlen;
-  ssize_t padlen;
+  nghttp2_ssize padlen;
   int rv;
   int busy = 0;
   nghttp2_frame_hd cont_hd;
@@ -5841,7 +5875,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
   }
 
   if (!nghttp2_session_want_read(session)) {
-    return (ssize_t)inlen;
+    return (nghttp2_ssize)inlen;
   }
 
   for (;;) {
@@ -5871,7 +5905,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
       in += readlen;
 
       if (nghttp2_buf_mark_avail(&iframe->sbuf)) {
-        return (ssize_t)(in - first);
+        return (nghttp2_ssize)(in - first);
       }
 
       if (iframe->sbuf.pos[3] != NGHTTP2_SETTINGS ||
@@ -5893,7 +5927,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
           return rv;
         }
 
-        return (ssize_t)inlen;
+        return (nghttp2_ssize)inlen;
       }
 
       iframe->state = NGHTTP2_IB_READ_HEAD;
@@ -5908,7 +5942,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
       in += readlen;
 
       if (nghttp2_buf_mark_avail(&iframe->sbuf)) {
-        return (ssize_t)(in - first);
+        return (nghttp2_ssize)(in - first);
       }
 
       nghttp2_frame_unpack_frame_hd(&iframe->frame.hd, iframe->sbuf.pos);
@@ -5929,7 +5963,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
           return rv;
         }
 
-        return (ssize_t)inlen;
+        return (nghttp2_ssize)inlen;
       }
 
       switch (iframe->frame.hd.type) {
@@ -5944,7 +5978,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
 
         rv = session_on_data_received_fail_fast(session);
         if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-          return (ssize_t)inlen;
+          return (nghttp2_ssize)inlen;
         }
         if (rv == NGHTTP2_ERR_IGN_PAYLOAD) {
           DEBUGF("recv: DATA not allowed stream_id=%d\n",
@@ -5966,7 +6000,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
           if (nghttp2_is_fatal(rv)) {
             return rv;
           }
-          return (ssize_t)inlen;
+          return (nghttp2_ssize)inlen;
         }
 
         if (rv == 1) {
@@ -5993,7 +6027,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
           if (nghttp2_is_fatal(rv)) {
             return rv;
           }
-          return (ssize_t)inlen;
+          return (nghttp2_ssize)inlen;
         }
 
         if (rv == 1) {
@@ -6036,7 +6070,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
         busy = 1;
 
         if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-          return (ssize_t)inlen;
+          return (nghttp2_ssize)inlen;
         }
 
         if (rv == NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE) {
@@ -6137,7 +6171,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
             if (nghttp2_is_fatal(rv)) {
               return rv;
             }
-            return (ssize_t)inlen;
+            return (nghttp2_ssize)inlen;
           }
 
           iframe->iv = nghttp2_mem_malloc(mem, sizeof(nghttp2_settings_entry) *
@@ -6175,7 +6209,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
           if (nghttp2_is_fatal(rv)) {
             return rv;
           }
-          return (ssize_t)inlen;
+          return (nghttp2_ssize)inlen;
         }
 
         if (rv == 1) {
@@ -6235,7 +6269,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
           return rv;
         }
 
-        return (ssize_t)inlen;
+        return (nghttp2_ssize)inlen;
       default:
         DEBUGF("recv: extension frame\n");
 
@@ -6346,7 +6380,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
               if (nghttp2_is_fatal(rv)) {
                 return rv;
               }
-              return (ssize_t)inlen;
+              return (nghttp2_ssize)inlen;
             }
 
             if (iframe->payloadleft < 4) {
@@ -6404,11 +6438,11 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
       in += readlen;
       iframe->payloadleft -= readlen;
 
-      DEBUGF("recv: readlen=%zu, payloadleft=%zu, left=%zd\n", readlen,
+      DEBUGF("recv: readlen=%zu, payloadleft=%zu, left=%zu\n", readlen,
              iframe->payloadleft, nghttp2_buf_mark_avail(&iframe->sbuf));
 
       if (nghttp2_buf_mark_avail(&iframe->sbuf)) {
-        return (ssize_t)(in - first);
+        return (nghttp2_ssize)(in - first);
       }
 
       switch (iframe->frame.hd.type) {
@@ -6424,7 +6458,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
             if (nghttp2_is_fatal(rv)) {
               return rv;
             }
-            return (ssize_t)inlen;
+            return (nghttp2_ssize)inlen;
           }
           iframe->frame.headers.padlen = (size_t)padlen;
 
@@ -6451,7 +6485,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
         busy = 1;
 
         if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-          return (ssize_t)inlen;
+          return (nghttp2_ssize)inlen;
         }
 
         if (rv == NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE) {
@@ -6481,7 +6515,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
           }
 
           if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-            return (ssize_t)inlen;
+            return (nghttp2_ssize)inlen;
           }
         }
 
@@ -6495,7 +6529,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
         }
 
         if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-          return (ssize_t)inlen;
+          return (nghttp2_ssize)inlen;
         }
 
         session_inbound_frame_reset(session);
@@ -6513,7 +6547,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
             if (nghttp2_is_fatal(rv)) {
               return rv;
             }
-            return (ssize_t)inlen;
+            return (nghttp2_ssize)inlen;
           }
 
           iframe->frame.push_promise.padlen = (size_t)padlen;
@@ -6539,7 +6573,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
         busy = 1;
 
         if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-          return (ssize_t)inlen;
+          return (nghttp2_ssize)inlen;
         }
 
         if (rv == NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE) {
@@ -6568,7 +6602,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
         }
 
         if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-          return (ssize_t)inlen;
+          return (nghttp2_ssize)inlen;
         }
 
         session_inbound_frame_reset(session);
@@ -6603,7 +6637,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
         }
 
         if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-          return (ssize_t)inlen;
+          return (nghttp2_ssize)inlen;
         }
 
         session_inbound_frame_reset(session);
@@ -6661,7 +6695,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
       break;
     case NGHTTP2_IB_READ_HEADER_BLOCK:
     case NGHTTP2_IB_IGN_HEADER_BLOCK: {
-      ssize_t data_readlen;
+      nghttp2_ssize data_readlen;
       size_t trail_padlen;
       int final;
 #ifdef DEBUGBUILD
@@ -6705,14 +6739,14 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
         }
 
         if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-          return (ssize_t)inlen;
+          return (nghttp2_ssize)inlen;
         }
 
         if (rv == NGHTTP2_ERR_PAUSE) {
           in += hd_proclen;
           iframe->payloadleft -= hd_proclen;
 
-          return (ssize_t)(in - first);
+          return (nghttp2_ssize)(in - first);
         }
 
         if (rv == NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE) {
@@ -6819,7 +6853,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
 
       assert(iframe->state == NGHTTP2_IB_IGN_ALL);
 
-      return (ssize_t)inlen;
+      return (nghttp2_ssize)inlen;
     case NGHTTP2_IB_READ_SETTINGS:
       DEBUGF("recv: [IB_READ_SETTINGS]\n");
 
@@ -6849,7 +6883,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
       }
 
       if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-        return (ssize_t)inlen;
+        return (nghttp2_ssize)inlen;
       }
 
       session_inbound_frame_reset(session);
@@ -6883,7 +6917,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
       }
 
       if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-        return (ssize_t)inlen;
+        return (nghttp2_ssize)inlen;
       }
 
       session_inbound_frame_reset(session);
@@ -6903,7 +6937,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
       in += readlen;
 
       if (nghttp2_buf_mark_avail(&iframe->sbuf)) {
-        return (ssize_t)(in - first);
+        return (nghttp2_ssize)(in - first);
       }
 
       nghttp2_frame_unpack_frame_hd(&cont_hd, iframe->sbuf.pos);
@@ -6925,7 +6959,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
           return rv;
         }
 
-        return (ssize_t)inlen;
+        return (nghttp2_ssize)inlen;
       }
 
       /* CONTINUATION won't bear NGHTTP2_PADDED flag */
@@ -6961,7 +6995,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
              iframe->payloadleft, nghttp2_buf_mark_avail(&iframe->sbuf));
 
       if (nghttp2_buf_mark_avail(&iframe->sbuf)) {
-        return (ssize_t)(in - first);
+        return (nghttp2_ssize)(in - first);
       }
 
       /* Pad Length field is subject to flow control */
@@ -6971,7 +7005,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
       }
 
       if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-        return (ssize_t)inlen;
+        return (nghttp2_ssize)inlen;
       }
 
       /* Pad Length field is consumed immediately */
@@ -6983,7 +7017,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
       }
 
       if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-        return (ssize_t)inlen;
+        return (nghttp2_ssize)inlen;
       }
 
       stream = nghttp2_session_get_stream(session, iframe->frame.hd.stream_id);
@@ -7006,7 +7040,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
         if (nghttp2_is_fatal(rv)) {
           return rv;
         }
-        return (ssize_t)inlen;
+        return (nghttp2_ssize)inlen;
       }
 
       iframe->frame.data.padlen = (size_t)padlen;
@@ -7033,7 +7067,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
              iframe->payloadleft);
 
       if (readlen > 0) {
-        ssize_t data_readlen;
+        nghttp2_ssize data_readlen;
 
         rv = nghttp2_session_update_recv_connection_window_size(session,
                                                                 readlen);
@@ -7042,7 +7076,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
         }
 
         if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-          return (ssize_t)inlen;
+          return (nghttp2_ssize)inlen;
         }
 
         rv = nghttp2_session_update_recv_stream_window_size(
@@ -7061,7 +7095,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
           data_readlen = 0;
         }
 
-        padlen = (ssize_t)readlen - data_readlen;
+        padlen = (nghttp2_ssize)readlen - data_readlen;
 
         if (padlen > 0) {
           /* Padding is considered as "consumed" immediately */
@@ -7073,11 +7107,11 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
           }
 
           if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-            return (ssize_t)inlen;
+            return (nghttp2_ssize)inlen;
           }
         }
 
-        DEBUGF("recv: data_readlen=%zd\n", data_readlen);
+        DEBUGF("recv: data_readlen=%td\n", data_readlen);
 
         if (data_readlen > 0) {
           if (session_enforce_http_messaging(session)) {
@@ -7092,7 +7126,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
                 }
 
                 if (iframe->state == NGHTTP2_IB_IGN_DATA) {
-                  return (ssize_t)inlen;
+                  return (nghttp2_ssize)inlen;
                 }
               }
 
@@ -7111,7 +7145,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
                 session, iframe->frame.hd.flags, iframe->frame.hd.stream_id,
                 in - readlen, (size_t)data_readlen, session->user_data);
             if (rv == NGHTTP2_ERR_PAUSE) {
-              return (ssize_t)(in - first);
+              return (nghttp2_ssize)(in - first);
             }
 
             if (nghttp2_is_fatal(rv)) {
@@ -7153,7 +7187,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
         }
 
         if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-          return (ssize_t)inlen;
+          return (nghttp2_ssize)inlen;
         }
 
         if (session->opt_flags & NGHTTP2_OPTMASK_NO_AUTO_WINDOW_UPDATE) {
@@ -7166,7 +7200,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
           }
 
           if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-            return (ssize_t)inlen;
+            return (nghttp2_ssize)inlen;
           }
         }
       }
@@ -7179,7 +7213,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
 
       break;
     case NGHTTP2_IB_IGN_ALL:
-      return (ssize_t)inlen;
+      return (nghttp2_ssize)inlen;
     case NGHTTP2_IB_READ_EXTENSION_PAYLOAD:
       DEBUGF("recv: [IB_READ_EXTENSION_PAYLOAD]\n");
 
@@ -7274,7 +7308,7 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
       }
 
       if (iframe->state == NGHTTP2_IB_IGN_ALL) {
-        return (ssize_t)inlen;
+        return (nghttp2_ssize)inlen;
       }
 
       session_inbound_frame_reset(session);
@@ -7291,16 +7325,17 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
 
   assert(in == last);
 
-  return (ssize_t)(in - first);
+  return (nghttp2_ssize)(in - first);
 }
 
 int nghttp2_session_recv(nghttp2_session *session) {
   uint8_t buf[NGHTTP2_INBOUND_BUFFER_LENGTH];
   while (1) {
-    ssize_t readlen;
+    nghttp2_ssize readlen;
     readlen = session_recv(session, buf, sizeof(buf));
     if (readlen > 0) {
-      ssize_t proclen = nghttp2_session_mem_recv(session, buf, (size_t)readlen);
+      nghttp2_ssize proclen =
+          nghttp2_session_mem_recv2(session, buf, (size_t)readlen);
       if (proclen < 0) {
         return (int)proclen;
       }
@@ -7642,8 +7677,8 @@ int nghttp2_session_pack_data(nghttp2_session *session, nghttp2_bufs *bufs,
                               nghttp2_stream *stream) {
   int rv;
   uint32_t data_flags;
-  ssize_t payloadlen;
-  ssize_t padded_payloadlen;
+  nghttp2_ssize payloadlen;
+  nghttp2_ssize padded_payloadlen;
   nghttp2_buf *buf;
   size_t max_payloadlen;
 
@@ -7651,19 +7686,26 @@ int nghttp2_session_pack_data(nghttp2_session *session, nghttp2_bufs *bufs,
 
   buf = &bufs->cur->buf;
 
-  if (session->callbacks.read_length_callback) {
-
-    payloadlen = session->callbacks.read_length_callback(
-        session, frame->hd.type, stream->stream_id, session->remote_window_size,
-        stream->remote_window_size, session->remote_settings.max_frame_size,
-        session->user_data);
+  if (session->callbacks.read_length_callback2 ||
+      session->callbacks.read_length_callback) {
+    if (session->callbacks.read_length_callback2) {
+      payloadlen = session->callbacks.read_length_callback2(
+          session, frame->hd.type, stream->stream_id,
+          session->remote_window_size, stream->remote_window_size,
+          session->remote_settings.max_frame_size, session->user_data);
+    } else {
+      payloadlen = (nghttp2_ssize)session->callbacks.read_length_callback(
+          session, frame->hd.type, stream->stream_id,
+          session->remote_window_size, stream->remote_window_size,
+          session->remote_settings.max_frame_size, session->user_data);
+    }
 
-    DEBUGF("send: read_length_callback=%zd\n", payloadlen);
+    DEBUGF("send: read_length_callback=%td\n", payloadlen);
 
     payloadlen = nghttp2_session_enforce_flow_control_limits(session, stream,
                                                              payloadlen);
 
-    DEBUGF("send: read_length_callback after flow control=%zd\n", payloadlen);
+    DEBUGF("send: read_length_callback after flow control=%td\n", payloadlen);
 
     if (payloadlen <= 0) {
       return NGHTTP2_ERR_CALLBACK_FAILURE;
@@ -7679,9 +7721,9 @@ int nghttp2_session_pack_data(nghttp2_session *session, nghttp2_bufs *bufs,
         DEBUGF("send: realloc buffer failed rv=%d", rv);
         /* If reallocation failed, old buffers are still in tact.  So
            use safe limit. */
-        payloadlen = (ssize_t)datamax;
+        payloadlen = (nghttp2_ssize)datamax;
 
-        DEBUGF("send: use safe limit payloadlen=%zd", payloadlen);
+        DEBUGF("send: use safe limit payloadlen=%td", payloadlen);
       } else {
         assert(&session->aob.framebufs == bufs);
 
@@ -7695,9 +7737,23 @@ int nghttp2_session_pack_data(nghttp2_session *session, nghttp2_bufs *bufs,
   assert(nghttp2_buf_avail(buf) >= datamax);
 
   data_flags = NGHTTP2_DATA_FLAG_NONE;
-  payloadlen = aux_data->data_prd.read_callback(
-      session, frame->hd.stream_id, buf->pos, datamax, &data_flags,
-      &aux_data->data_prd.source, session->user_data);
+  switch (aux_data->dpw.version) {
+  case NGHTTP2_DATA_PROVIDER_V1:
+    payloadlen = (nghttp2_ssize)aux_data->dpw.data_prd.v1.read_callback(
+        session, frame->hd.stream_id, buf->pos, datamax, &data_flags,
+        &aux_data->dpw.data_prd.source, session->user_data);
+
+    break;
+  case NGHTTP2_DATA_PROVIDER_V2:
+    payloadlen = aux_data->dpw.data_prd.v2.read_callback(
+        session, frame->hd.stream_id, buf->pos, datamax, &data_flags,
+        &aux_data->dpw.data_prd.source, session->user_data);
+
+    break;
+  default:
+    assert(0);
+    abort();
+  }
 
   if (payloadlen == NGHTTP2_ERR_DEFERRED ||
       payloadlen == NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE ||
@@ -8275,7 +8331,7 @@ int nghttp2_session_change_stream_priority(
   /* We don't intentionally call nghttp2_session_adjust_idle_stream()
      so that idle stream created by this function, and existing ones
      are kept for application.  We will adjust number of idle stream
-     in nghttp2_session_mem_send or nghttp2_session_mem_recv is
+     in nghttp2_session_mem_send2 or nghttp2_session_mem_recv2 is
      called. */
   return 0;
 }
@@ -8313,7 +8369,7 @@ int nghttp2_session_create_idle_stream(nghttp2_session *session,
   /* We don't intentionally call nghttp2_session_adjust_idle_stream()
      so that idle stream created by this function, and existing ones
      are kept for application.  We will adjust number of idle stream
-     in nghttp2_session_mem_send or nghttp2_session_mem_recv is
+     in nghttp2_session_mem_send2 or nghttp2_session_mem_recv2 is
      called. */
   return 0;
 }
diff --git a/contrib/libs/nghttp2/lib/nghttp2_submit.c b/contrib/libs/nghttp2/lib/nghttp2_submit.c
index f5554eb564..f947969cd9 100644
--- a/contrib/libs/nghttp2/lib/nghttp2_submit.c
+++ b/contrib/libs/nghttp2/lib/nghttp2_submit.c
@@ -68,7 +68,7 @@ static int32_t submit_headers_shared(nghttp2_session *session, uint8_t flags,
                                      int32_t stream_id,
                                      const nghttp2_priority_spec *pri_spec,
                                      nghttp2_nv *nva_copy, size_t nvlen,
-                                     const nghttp2_data_provider *data_prd,
+                                     const nghttp2_data_provider_wrap *dpw,
                                      void *stream_user_data) {
   int rv;
   uint8_t flags_copy;
@@ -87,8 +87,8 @@ static int32_t submit_headers_shared(nghttp2_session *session, uint8_t flags,
 
   nghttp2_outbound_item_init(item);
 
-  if (data_prd != NULL && data_prd->read_callback != NULL) {
-    item->aux_data.headers.data_prd = *data_prd;
+  if (dpw != NULL && dpw->data_prd.read_callback != NULL) {
+    item->aux_data.headers.dpw = *dpw;
   }
 
   item->aux_data.headers.stream_user_data = stream_user_data;
@@ -143,7 +143,7 @@ static int32_t submit_headers_shared_nva(nghttp2_session *session,
                                          uint8_t flags, int32_t stream_id,
                                          const nghttp2_priority_spec *pri_spec,
                                          const nghttp2_nv *nva, size_t nvlen,
-                                         const nghttp2_data_provider *data_prd,
+                                         const nghttp2_data_provider_wrap *dpw,
                                          void *stream_user_data) {
   int rv;
   nghttp2_nv *nva_copy;
@@ -165,7 +165,7 @@ static int32_t submit_headers_shared_nva(nghttp2_session *session,
   }
 
   return submit_headers_shared(session, flags, stream_id, &copy_pri_spec,
-                               nva_copy, nvlen, data_prd, stream_user_data);
+                               nva_copy, nvlen, dpw, stream_user_data);
 }
 
 int nghttp2_submit_trailer(nghttp2_session *session, int32_t stream_id,
@@ -740,9 +740,9 @@ fail_item_malloc:
 }
 
 static uint8_t set_request_flags(const nghttp2_priority_spec *pri_spec,
-                                 const nghttp2_data_provider *data_prd) {
+                                 const nghttp2_data_provider_wrap *dpw) {
   uint8_t flags = NGHTTP2_FLAG_NONE;
-  if (data_prd == NULL || data_prd->read_callback == NULL) {
+  if (dpw == NULL || dpw->data_prd.read_callback == NULL) {
     flags |= NGHTTP2_FLAG_END_STREAM;
   }
 
@@ -753,11 +753,11 @@ static uint8_t set_request_flags(const nghttp2_priority_spec *pri_spec,
   return flags;
 }
 
-int32_t nghttp2_submit_request(nghttp2_session *session,
-                               const nghttp2_priority_spec *pri_spec,
-                               const nghttp2_nv *nva, size_t nvlen,
-                               const nghttp2_data_provider *data_prd,
-                               void *stream_user_data) {
+static int32_t submit_request_shared(nghttp2_session *session,
+                                     const nghttp2_priority_spec *pri_spec,
+                                     const nghttp2_nv *nva, size_t nvlen,
+                                     const nghttp2_data_provider_wrap *dpw,
+                                     void *stream_user_data) {
   uint8_t flags;
   int rv;
 
@@ -775,23 +775,47 @@ int32_t nghttp2_submit_request(nghttp2_session *session,
     pri_spec = NULL;
   }
 
-  flags = set_request_flags(pri_spec, data_prd);
+  flags = set_request_flags(pri_spec, dpw);
 
   return submit_headers_shared_nva(session, flags, -1, pri_spec, nva, nvlen,
-                                   data_prd, stream_user_data);
+                                   dpw, stream_user_data);
+}
+
+int32_t nghttp2_submit_request(nghttp2_session *session,
+                               const nghttp2_priority_spec *pri_spec,
+                               const nghttp2_nv *nva, size_t nvlen,
+                               const nghttp2_data_provider *data_prd,
+                               void *stream_user_data) {
+  nghttp2_data_provider_wrap dpw;
+
+  return submit_request_shared(session, pri_spec, nva, nvlen,
+                               nghttp2_data_provider_wrap_v1(&dpw, data_prd),
+                               stream_user_data);
+}
+
+int32_t nghttp2_submit_request2(nghttp2_session *session,
+                                const nghttp2_priority_spec *pri_spec,
+                                const nghttp2_nv *nva, size_t nvlen,
+                                const nghttp2_data_provider2 *data_prd,
+                                void *stream_user_data) {
+  nghttp2_data_provider_wrap dpw;
+
+  return submit_request_shared(session, pri_spec, nva, nvlen,
+                               nghttp2_data_provider_wrap_v2(&dpw, data_prd),
+                               stream_user_data);
 }
 
-static uint8_t set_response_flags(const nghttp2_data_provider *data_prd) {
+static uint8_t set_response_flags(const nghttp2_data_provider_wrap *dpw) {
   uint8_t flags = NGHTTP2_FLAG_NONE;
-  if (data_prd == NULL || data_prd->read_callback == NULL) {
+  if (dpw == NULL || dpw->data_prd.read_callback == NULL) {
     flags |= NGHTTP2_FLAG_END_STREAM;
   }
   return flags;
 }
 
-int nghttp2_submit_response(nghttp2_session *session, int32_t stream_id,
-                            const nghttp2_nv *nva, size_t nvlen,
-                            const nghttp2_data_provider *data_prd) {
+static int submit_response_shared(nghttp2_session *session, int32_t stream_id,
+                                  const nghttp2_nv *nva, size_t nvlen,
+                                  const nghttp2_data_provider_wrap *dpw) {
   uint8_t flags;
 
   if (stream_id <= 0) {
@@ -802,14 +826,32 @@ int nghttp2_submit_response(nghttp2_session *session, int32_t stream_id,
     return NGHTTP2_ERR_PROTO;
   }
 
-  flags = set_response_flags(data_prd);
+  flags = set_response_flags(dpw);
   return submit_headers_shared_nva(session, flags, stream_id, NULL, nva, nvlen,
-                                   data_prd, NULL);
+                                   dpw, NULL);
 }
 
-int nghttp2_submit_data(nghttp2_session *session, uint8_t flags,
-                        int32_t stream_id,
-                        const nghttp2_data_provider *data_prd) {
+int nghttp2_submit_response(nghttp2_session *session, int32_t stream_id,
+                            const nghttp2_nv *nva, size_t nvlen,
+                            const nghttp2_data_provider *data_prd) {
+  nghttp2_data_provider_wrap dpw;
+
+  return submit_response_shared(session, stream_id, nva, nvlen,
+                                nghttp2_data_provider_wrap_v1(&dpw, data_prd));
+}
+
+int nghttp2_submit_response2(nghttp2_session *session, int32_t stream_id,
+                             const nghttp2_nv *nva, size_t nvlen,
+                             const nghttp2_data_provider2 *data_prd) {
+  nghttp2_data_provider_wrap dpw;
+
+  return submit_response_shared(session, stream_id, nva, nvlen,
+                                nghttp2_data_provider_wrap_v2(&dpw, data_prd));
+}
+
+int nghttp2_submit_data_shared(nghttp2_session *session, uint8_t flags,
+                               int32_t stream_id,
+                               const nghttp2_data_provider_wrap *dpw) {
   int rv;
   nghttp2_outbound_item *item;
   nghttp2_frame *frame;
@@ -832,7 +874,7 @@ int nghttp2_submit_data(nghttp2_session *session, uint8_t flags,
 
   frame = &item->frame;
   aux_data = &item->aux_data.data;
-  aux_data->data_prd = *data_prd;
+  aux_data->dpw = *dpw;
   aux_data->eof = 0;
   aux_data->flags = nflags;
 
@@ -848,9 +890,37 @@ int nghttp2_submit_data(nghttp2_session *session, uint8_t flags,
   return 0;
 }
 
+int nghttp2_submit_data(nghttp2_session *session, uint8_t flags,
+                        int32_t stream_id,
+                        const nghttp2_data_provider *data_prd) {
+  nghttp2_data_provider_wrap dpw;
+
+  assert(data_prd);
+
+  return nghttp2_submit_data_shared(
+      session, flags, stream_id, nghttp2_data_provider_wrap_v1(&dpw, data_prd));
+}
+
+int nghttp2_submit_data2(nghttp2_session *session, uint8_t flags,
+                         int32_t stream_id,
+                         const nghttp2_data_provider2 *data_prd) {
+  nghttp2_data_provider_wrap dpw;
+
+  assert(data_prd);
+
+  return nghttp2_submit_data_shared(
+      session, flags, stream_id, nghttp2_data_provider_wrap_v2(&dpw, data_prd));
+}
+
 ssize_t nghttp2_pack_settings_payload(uint8_t *buf, size_t buflen,
                                       const nghttp2_settings_entry *iv,
                                       size_t niv) {
+  return (ssize_t)nghttp2_pack_settings_payload2(buf, buflen, iv, niv);
+}
+
+nghttp2_ssize nghttp2_pack_settings_payload2(uint8_t *buf, size_t buflen,
+                                             const nghttp2_settings_entry *iv,
+                                             size_t niv) {
   if (!nghttp2_iv_check(iv, niv)) {
     return NGHTTP2_ERR_INVALID_ARGUMENT;
   }
@@ -859,7 +929,7 @@ ssize_t nghttp2_pack_settings_payload(uint8_t *buf, size_t buflen,
     return NGHTTP2_ERR_INSUFF_BUFSIZE;
   }
 
-  return (ssize_t)nghttp2_frame_pack_settings_payload(buf, iv, niv);
+  return (nghttp2_ssize)nghttp2_frame_pack_settings_payload(buf, iv, niv);
 }
 
 int nghttp2_submit_extension(nghttp2_session *session, uint8_t type,
@@ -875,7 +945,8 @@ int nghttp2_submit_extension(nghttp2_session *session, uint8_t type,
     return NGHTTP2_ERR_INVALID_ARGUMENT;
   }
 
-  if (!session->callbacks.pack_extension_callback) {
+  if (!session->callbacks.pack_extension_callback2 &&
+      !session->callbacks.pack_extension_callback) {
     return NGHTTP2_ERR_INVALID_STATE;
   }
 
diff --git a/contrib/libs/nghttp2/lib/nghttp2_submit.h b/contrib/libs/nghttp2/lib/nghttp2_submit.h
index 74d702fbcf..96781d2a27 100644
--- a/contrib/libs/nghttp2/lib/nghttp2_submit.h
+++ b/contrib/libs/nghttp2/lib/nghttp2_submit.h
@@ -31,4 +31,10 @@
 
 #include <nghttp2/nghttp2.h>
 
+typedef struct nghttp2_data_provider_wrap nghttp2_data_provider_wrap;
+
+int nghttp2_submit_data_shared(nghttp2_session *session, uint8_t flags,
+                               int32_t stream_id,
+                               const nghttp2_data_provider_wrap *dpw);
+
 #endif /* NGHTTP2_SUBMIT_H */
diff --git a/contrib/libs/nghttp2/ya.make b/contrib/libs/nghttp2/ya.make
index 0c865394e7..12c83b34a5 100644
--- a/contrib/libs/nghttp2/ya.make
+++ b/contrib/libs/nghttp2/ya.make
@@ -9,9 +9,9 @@ LICENSE(
 
 LICENSE_TEXTS(.yandex_meta/licenses.list.txt)
 
-VERSION(1.59.0)
+VERSION(1.60.0)
 
-ORIGINAL_SOURCE(https://github.com/nghttp2/nghttp2/archive/v1.59.0.tar.gz)
+ORIGINAL_SOURCE(https://github.com/nghttp2/nghttp2/archive/v1.60.0.tar.gz)
 
 ADDINCL(
     GLOBAL contrib/libs/nghttp2/lib/includes