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path: root/contrib/restricted/aws/s2n/tls/extensions/s2n_cookie.c
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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_cookie.h" 
#include "tls/s2n_tls.h" 
 
#define S2N_SIZE_OF_EXTENSION_TYPE          2 
#define S2N_SIZE_OF_EXTENSION_DATA_SIZE     2 
#define S2N_SIZE_OF_COOKIE_DATA_SIZE        2 
 
const s2n_extension_type s2n_client_cookie_extension = { 
    .iana_value = TLS_EXTENSION_COOKIE, 
    .is_response = true, 
    .send = s2n_extension_send_noop, 
    .recv = s2n_extension_recv_noop, 
    .should_send = s2n_extension_never_send, 
    .if_missing = s2n_extension_noop_if_missing, 
}; 
 
static bool s2n_cookie_should_send(struct s2n_connection *conn); 
static int s2n_cookie_send(struct s2n_connection *conn, struct s2n_stuffer *out); 
static int s2n_cookie_recv(struct s2n_connection *conn, struct s2n_stuffer *extension); 
 
const s2n_extension_type s2n_server_cookie_extension = { 
    .iana_value = TLS_EXTENSION_COOKIE, 
    .is_response = false, 
    .send = s2n_cookie_send, 
    .recv = s2n_cookie_recv, 
    .should_send = s2n_cookie_should_send, 
    .if_missing = s2n_extension_noop_if_missing, 
}; 
 
static bool s2n_cookie_should_send(struct s2n_connection *conn) 
{ 
    return s2n_extension_send_if_tls13_connection(conn) 
            && conn && s2n_stuffer_data_available(&conn->cookie_stuffer) > 0; 
} 
 
static int s2n_cookie_send(struct s2n_connection *conn, struct s2n_stuffer *out) 
{ 
    notnull_check(conn); 
    uint16_t cookie_size = s2n_stuffer_data_available(&conn->cookie_stuffer); 
    GUARD(s2n_stuffer_write_uint16(out, cookie_size)); 
    GUARD(s2n_stuffer_copy(&conn->cookie_stuffer, out, cookie_size)); 
    return S2N_SUCCESS; 
} 
 
static int s2n_cookie_recv(struct s2n_connection *conn, struct s2n_stuffer *extension) 
{ 
    notnull_check(conn); 
    if (s2n_connection_get_protocol_version(conn) < S2N_TLS13) { 
        return S2N_SUCCESS; 
    } 
 
    uint16_t cookie_len; 
    GUARD(s2n_stuffer_read_uint16(extension, &cookie_len)); 
    ENSURE_POSIX(s2n_stuffer_data_available(extension) == cookie_len, S2N_ERR_BAD_MESSAGE); 
 
    GUARD(s2n_stuffer_wipe(&conn->cookie_stuffer)); 
    GUARD(s2n_stuffer_resize(&conn->cookie_stuffer, cookie_len)); 
    GUARD(s2n_stuffer_copy(extension, &conn->cookie_stuffer, cookie_len)); 
    return S2N_SUCCESS; 
} 
 
/* Old-style extension functions -- remove after extensions refactor is complete */ 
 
int s2n_extensions_cookie_size(struct s2n_connection *conn) 
{ 
    GUARD(s2n_stuffer_reread(&conn->cookie_stuffer)); 
 
    if (s2n_stuffer_data_available(&conn->cookie_stuffer) == 0) { 
        return 0; 
    } 
 
    const int cookie_extension_size = S2N_SIZE_OF_EXTENSION_TYPE 
        + S2N_SIZE_OF_EXTENSION_DATA_SIZE 
        + S2N_SIZE_OF_COOKIE_DATA_SIZE 
        + s2n_stuffer_data_available(&conn->cookie_stuffer); 
 
    return cookie_extension_size; 
} 
 
int s2n_extensions_cookie_recv(struct s2n_connection *conn, struct s2n_stuffer *extension) 
{ 
    return s2n_extension_send(&s2n_server_cookie_extension, conn, extension); 
} 
 
int s2n_extensions_cookie_send(struct s2n_connection *conn, struct s2n_stuffer *out) 
{ 
    return s2n_extension_send(&s2n_server_cookie_extension, conn, out); 
}