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/*
* DTLS implementation written by Nagendra Modadugu
* (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
*/
/* ====================================================================
* Copyright (c) 1999-2005 The OpenSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
*
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* openssl-core@OpenSSL.org.
*
* 5. Products derived from this software may not be called "OpenSSL"
* nor may "OpenSSL" appear in their names without prior written
* permission of the OpenSSL Project.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
*
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*
* This product includes cryptographic software written by Eric Young
* (eay@cryptsoft.com). This product includes software written by Tim
* Hudson (tjh@cryptsoft.com). */
#include <openssl/ssl.h>
#include <assert.h>
#include <limits.h>
#include <string.h>
#include <openssl/err.h>
#include <openssl/mem.h>
#include <openssl/nid.h>
#include "internal.h"
#if defined(OPENSSL_WINDOWS)
#include <sys/timeb.h>
#else
#include <sys/socket.h>
#include <sys/time.h>
#endif
/* DTLS1_MTU_TIMEOUTS is the maximum number of timeouts to expire
* before starting to decrease the MTU. */
#define DTLS1_MTU_TIMEOUTS 2
/* DTLS1_MAX_TIMEOUTS is the maximum number of timeouts to expire
* before failing the DTLS handshake. */
#define DTLS1_MAX_TIMEOUTS 12
static void get_current_time(const SSL *ssl, struct timeval *out_clock);
int dtls1_new(SSL *ssl) {
DTLS1_STATE *d1;
if (!ssl3_new(ssl)) {
return 0;
}
d1 = OPENSSL_malloc(sizeof *d1);
if (d1 == NULL) {
ssl3_free(ssl);
return 0;
}
memset(d1, 0, sizeof *d1);
ssl->d1 = d1;
/* Set the version to the highest supported version.
*
* TODO(davidben): Move this field into |s3|, have it store the normalized
* protocol version, and implement this pre-negotiation quirk in |SSL_version|
* at the API boundary rather than in internal state. */
ssl->version = DTLS1_2_VERSION;
return 1;
}
void dtls1_free(SSL *ssl) {
ssl3_free(ssl);
if (ssl == NULL || ssl->d1 == NULL) {
return;
}
dtls_clear_incoming_messages(ssl);
dtls_clear_outgoing_messages(ssl);
OPENSSL_free(ssl->d1);
ssl->d1 = NULL;
}
int dtls1_supports_cipher(const SSL_CIPHER *cipher) {
/* DTLS does not support stream ciphers. The NULL cipher is rejected because
* it's not needed. */
return cipher->algorithm_enc != SSL_RC4 && cipher->algorithm_enc != SSL_eNULL;
}
void DTLSv1_set_initial_timeout_duration(SSL *ssl, unsigned int duration_ms) {
ssl->initial_timeout_duration_ms = duration_ms;
}
void dtls1_start_timer(SSL *ssl) {
/* If timer is not set, initialize duration (by default, 1 second) */
if (ssl->d1->next_timeout.tv_sec == 0 && ssl->d1->next_timeout.tv_usec == 0) {
ssl->d1->timeout_duration_ms = ssl->initial_timeout_duration_ms;
}
/* Set timeout to current time */
get_current_time(ssl, &ssl->d1->next_timeout);
/* Add duration to current time */
ssl->d1->next_timeout.tv_sec += ssl->d1->timeout_duration_ms / 1000;
ssl->d1->next_timeout.tv_usec += (ssl->d1->timeout_duration_ms % 1000) * 1000;
if (ssl->d1->next_timeout.tv_usec >= 1000000) {
ssl->d1->next_timeout.tv_sec++;
ssl->d1->next_timeout.tv_usec -= 1000000;
}
BIO_ctrl(ssl->rbio, BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
&ssl->d1->next_timeout);
}
int DTLSv1_get_timeout(const SSL *ssl, struct timeval *out) {
if (!SSL_IS_DTLS(ssl)) {
return 0;
}
/* If no timeout is set, just return NULL */
if (ssl->d1->next_timeout.tv_sec == 0 && ssl->d1->next_timeout.tv_usec == 0) {
return 0;
}
/* Get current time */
struct timeval timenow;
get_current_time(ssl, &timenow);
/* If timer already expired, set remaining time to 0 */
if (ssl->d1->next_timeout.tv_sec < timenow.tv_sec ||
(ssl->d1->next_timeout.tv_sec == timenow.tv_sec &&
ssl->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
memset(out, 0, sizeof(struct timeval));
return 1;
}
/* Calculate time left until timer expires */
memcpy(out, &ssl->d1->next_timeout, sizeof(struct timeval));
out->tv_sec -= timenow.tv_sec;
out->tv_usec -= timenow.tv_usec;
if (out->tv_usec < 0) {
out->tv_sec--;
out->tv_usec += 1000000;
}
/* If remaining time is less than 15 ms, set it to 0 to prevent issues
* because of small devergences with socket timeouts. */
if (out->tv_sec == 0 && out->tv_usec < 15000) {
memset(out, 0, sizeof(struct timeval));
}
return 1;
}
int dtls1_is_timer_expired(SSL *ssl) {
struct timeval timeleft;
/* Get time left until timeout, return false if no timer running */
if (!DTLSv1_get_timeout(ssl, &timeleft)) {
return 0;
}
/* Return false if timer is not expired yet */
if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
return 0;
}
/* Timer expired, so return true */
return 1;
}
void dtls1_double_timeout(SSL *ssl) {
ssl->d1->timeout_duration_ms *= 2;
if (ssl->d1->timeout_duration_ms > 60000) {
ssl->d1->timeout_duration_ms = 60000;
}
dtls1_start_timer(ssl);
}
void dtls1_stop_timer(SSL *ssl) {
/* Reset everything */
ssl->d1->num_timeouts = 0;
memset(&ssl->d1->next_timeout, 0, sizeof(struct timeval));
ssl->d1->timeout_duration_ms = ssl->initial_timeout_duration_ms;
BIO_ctrl(ssl->rbio, BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
&ssl->d1->next_timeout);
/* Clear retransmission buffer */
dtls_clear_outgoing_messages(ssl);
}
int dtls1_check_timeout_num(SSL *ssl) {
ssl->d1->num_timeouts++;
/* Reduce MTU after 2 unsuccessful retransmissions */
if (ssl->d1->num_timeouts > DTLS1_MTU_TIMEOUTS &&
!(SSL_get_options(ssl) & SSL_OP_NO_QUERY_MTU)) {
long mtu = BIO_ctrl(ssl->wbio, BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL);
if (mtu >= 0 && mtu <= (1 << 30) && (unsigned)mtu >= dtls1_min_mtu()) {
ssl->d1->mtu = (unsigned)mtu;
}
}
if (ssl->d1->num_timeouts > DTLS1_MAX_TIMEOUTS) {
/* fail the connection, enough alerts have been sent */
OPENSSL_PUT_ERROR(SSL, SSL_R_READ_TIMEOUT_EXPIRED);
return -1;
}
return 0;
}
int DTLSv1_handle_timeout(SSL *ssl) {
ssl->rwstate = SSL_NOTHING;
/* Functions which use SSL_get_error must clear the error queue on entry. */
ERR_clear_error();
if (!SSL_IS_DTLS(ssl)) {
return -1;
}
/* if no timer is expired, don't do anything */
if (!dtls1_is_timer_expired(ssl)) {
return 0;
}
dtls1_double_timeout(ssl);
if (dtls1_check_timeout_num(ssl) < 0) {
return -1;
}
dtls1_start_timer(ssl);
return dtls1_retransmit_outgoing_messages(ssl);
}
static void get_current_time(const SSL *ssl, struct timeval *out_clock) {
if (ssl->ctx->current_time_cb != NULL) {
ssl->ctx->current_time_cb(ssl, out_clock);
return;
}
#if defined(OPENSSL_WINDOWS)
struct _timeb time;
_ftime(&time);
out_clock->tv_sec = time.time;
out_clock->tv_usec = time.millitm * 1000;
#else
gettimeofday(out_clock, NULL);
#endif
}
void dtls1_expect_flight(SSL *ssl) {
dtls1_start_timer(ssl);
}
void dtls1_received_flight(SSL *ssl) {
dtls1_stop_timer(ssl);
}