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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 "tls/extensions/s2n_server_alpn.h"
#include "stuffer/s2n_stuffer.h"
#include "tls/s2n_connection.h"
#include "tls/s2n_tls.h"
#include "utils/s2n_safety.h"
bool s2n_server_alpn_should_send(struct s2n_connection *conn);
static int s2n_alpn_send(struct s2n_connection *conn, struct s2n_stuffer *out);
static int s2n_alpn_recv(struct s2n_connection *conn, struct s2n_stuffer *extension);
const s2n_extension_type s2n_server_alpn_extension = {
.iana_value = TLS_EXTENSION_ALPN,
.is_response = true,
.send = s2n_alpn_send,
.recv = s2n_alpn_recv,
.should_send = s2n_server_alpn_should_send,
.if_missing = s2n_extension_noop_if_missing,
};
bool s2n_server_alpn_should_send(struct s2n_connection *conn)
{
return conn && strlen(conn->application_protocol) > 0;
}
static int s2n_alpn_send(struct s2n_connection *conn, struct s2n_stuffer *out)
{
POSIX_ENSURE_REF(conn);
const uint8_t application_protocol_len = strlen(conn->application_protocol);
/* Size of protocol name list */
POSIX_GUARD(s2n_stuffer_write_uint16(out, application_protocol_len + sizeof(uint8_t)));
/* Single entry in protocol name list */
POSIX_GUARD(s2n_stuffer_write_uint8(out, application_protocol_len));
POSIX_GUARD(s2n_stuffer_write_bytes(out, (uint8_t *) conn->application_protocol, application_protocol_len));
return S2N_SUCCESS;
}
static int s2n_alpn_recv(struct s2n_connection *conn, struct s2n_stuffer *extension)
{
POSIX_ENSURE_REF(conn);
uint16_t size_of_all;
POSIX_GUARD(s2n_stuffer_read_uint16(extension, &size_of_all));
if (size_of_all > s2n_stuffer_data_available(extension) || size_of_all < 3) {
/* ignore invalid extension size */
return S2N_SUCCESS;
}
uint8_t protocol_len;
POSIX_GUARD(s2n_stuffer_read_uint8(extension, &protocol_len));
POSIX_ENSURE_LT(protocol_len, s2n_array_len(conn->application_protocol));
uint8_t *protocol = s2n_stuffer_raw_read(extension, protocol_len);
POSIX_ENSURE_REF(protocol);
/* copy the first protocol name */
POSIX_CHECKED_MEMCPY(conn->application_protocol, protocol, protocol_len);
conn->application_protocol[protocol_len] = '\0';
return S2N_SUCCESS;
}
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