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/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
#include "api/s2n.h"
#include "tls/extensions/s2n_early_data_indication.h"
#include "tls/s2n_connection.h"
#include "tls/s2n_early_data.h"
#include "tls/s2n_handshake.h"
#include "utils/s2n_safety.h"
static bool s2n_server_early_data_indication_should_send(struct s2n_connection *conn)
{
return conn && conn->early_data_state == S2N_EARLY_DATA_ACCEPTED;
}
/**
*= https://tools.ietf.org/rfc/rfc8446#section-4.2.10
*# A server which receives an "early_data" extension MUST behave in one
*# of three ways:
*#
*# - Ignore the extension and return a regular 1-RTT response.
**/
static int s2n_server_early_data_indication_is_missing(struct s2n_connection *conn)
{
POSIX_ENSURE_REF(conn);
if (conn->early_data_state == S2N_EARLY_DATA_REQUESTED) {
POSIX_GUARD_RESULT(s2n_connection_set_early_data_state(conn, S2N_EARLY_DATA_REJECTED));
}
return S2N_SUCCESS;
}
/**
* The server version of this extension is empty, so we don't read/write any data.
*
*= https://tools.ietf.org/rfc/rfc8446#section-4.2.10
*# The "extension_data" field of this extension contains an
*# "EarlyDataIndication" value.
*#
*# struct {} Empty;
*#
*# struct {
*# select (Handshake.msg_type) {
**
*= https://tools.ietf.org/rfc/rfc8446#section-4.2.10
*# case encrypted_extensions: Empty;
*# };
*# } EarlyDataIndication;
**/
/**
*= https://tools.ietf.org/rfc/rfc8446#section-4.2.10
*# A server which receives an "early_data" extension MUST behave in one
*# of three ways:
*
*= https://tools.ietf.org/rfc/rfc8446#section-4.2.10
*# - Return its own "early_data" extension in EncryptedExtensions,
*# indicating that it intends to process the early data.
**/
static int s2n_server_early_data_indication_send(struct s2n_connection *conn, struct s2n_stuffer *out)
{
return S2N_SUCCESS;
}
static int s2n_server_early_data_indication_recv(struct s2n_connection *conn, struct s2n_stuffer *in)
{
/**
*= https://tools.ietf.org/rfc/rfc8446#section-4.2.10
*# If any of these checks fail, the server MUST NOT respond with the
*# extension
**/
POSIX_ENSURE(s2n_early_data_is_valid_for_connection(conn), S2N_ERR_EARLY_DATA_NOT_ALLOWED);
POSIX_GUARD_RESULT(s2n_connection_set_early_data_state(conn, S2N_EARLY_DATA_ACCEPTED));
/* The client does not know for sure whether the server accepted early data until it receives
* this extension as part of the EncryptedExtensions message, after the handshake type has
* already been calculated. We'll need to manually update the handshake type.
*/
conn->handshake.handshake_type |= WITH_EARLY_DATA;
return S2N_SUCCESS;
}
const s2n_extension_type s2n_server_early_data_indication_extension = {
.iana_value = TLS_EXTENSION_EARLY_DATA,
.is_response = true,
.send = s2n_server_early_data_indication_send,
.recv = s2n_server_early_data_indication_recv,
.should_send = s2n_server_early_data_indication_should_send,
.if_missing = s2n_server_early_data_indication_is_missing,
};
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