blob: ef7a9c9495470af6a471c53f5b32cb26fbf79c3e [file] [log] [blame]
/*
* 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/base.h>
#include <limits.h>
#include <stdio.h>
#include <string.h>
#if defined(OPENSSL_WINDOWS)
#include <sys/timeb.h>
#else
#include <sys/socket.h>
#include <sys/time.h>
#endif
#include <openssl/err.h>
#include <openssl/mem.h>
#include <openssl/obj.h>
#include "internal.h"
/* 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 *s) {
DTLS1_STATE *d1;
if (!ssl3_new(s)) {
return 0;
}
d1 = OPENSSL_malloc(sizeof *d1);
if (d1 == NULL) {
ssl3_free(s);
return 0;
}
memset(d1, 0, sizeof *d1);
d1->buffered_messages = pqueue_new();
d1->sent_messages = pqueue_new();
if (!d1->buffered_messages || !d1->sent_messages) {
pqueue_free(d1->buffered_messages);
pqueue_free(d1->sent_messages);
OPENSSL_free(d1);
ssl3_free(s);
return 0;
}
s->d1 = d1;
/* Set the version to the highest version for DTLS. This controls the initial
* state of |s->enc_method| and what the API reports as the version prior to
* negotiation.
*
* TODO(davidben): This is fragile and confusing. */
s->version = DTLS1_2_VERSION;
return 1;
}
static void dtls1_clear_queues(SSL *s) {
pitem *item = NULL;
hm_fragment *frag = NULL;
while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) {
frag = (hm_fragment *)item->data;
dtls1_hm_fragment_free(frag);
pitem_free(item);
}
while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) {
frag = (hm_fragment *)item->data;
dtls1_hm_fragment_free(frag);
pitem_free(item);
}
}
void dtls1_free(SSL *s) {
ssl3_free(s);
if (s == NULL || s->d1 == NULL) {
return;
}
dtls1_clear_queues(s);
pqueue_free(s->d1->buffered_messages);
pqueue_free(s->d1->sent_messages);
OPENSSL_free(s->d1);
s->d1 = NULL;
}
int dtls1_supports_cipher(const SSL_CIPHER *cipher) {
/* DTLS does not support stream ciphers. */
return cipher->algorithm_enc != SSL_RC4;
}
void dtls1_start_timer(SSL *s) {
/* If timer is not set, initialize duration with 1 second */
if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
s->d1->timeout_duration = 1;
}
/* Set timeout to current time */
get_current_time(s, &s->d1->next_timeout);
/* Add duration to current time */
s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
&s->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 *s) {
struct timeval timeleft;
/* Get time left until timeout, return false if no timer running */
if (!DTLSv1_get_timeout(s, &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 *s) {
s->d1->timeout_duration *= 2;
if (s->d1->timeout_duration > 60) {
s->d1->timeout_duration = 60;
}
dtls1_start_timer(s);
}
void dtls1_stop_timer(SSL *s) {
/* Reset everything */
s->d1->num_timeouts = 0;
memset(&s->d1->next_timeout, 0, sizeof(struct timeval));
s->d1->timeout_duration = 1;
BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
&s->d1->next_timeout);
/* Clear retransmission buffer */
dtls1_clear_record_buffer(s);
}
int dtls1_check_timeout_num(SSL *s) {
s->d1->num_timeouts++;
/* Reduce MTU after 2 unsuccessful retransmissions */
if (s->d1->num_timeouts > DTLS1_MTU_TIMEOUTS &&
!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
long mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0,
NULL);
if (mtu >= 0 && mtu <= (1 << 30) && (unsigned)mtu >= dtls1_min_mtu()) {
s->d1->mtu = (unsigned)mtu;
}
}
if (s->d1->num_timeouts > DTLS1_MAX_TIMEOUTS) {
/* fail the connection, enough alerts have been sent */
OPENSSL_PUT_ERROR(SSL, dtls1_check_timeout_num, SSL_R_READ_TIMEOUT_EXPIRED);
return -1;
}
return 0;
}
int DTLSv1_handle_timeout(SSL *ssl) {
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_buffered_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
}
int dtls1_set_handshake_header(SSL *s, int htype, unsigned long len) {
uint8_t *message = (uint8_t *)s->init_buf->data;
const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
uint8_t serialised_header[DTLS1_HM_HEADER_LENGTH];
uint8_t *p = serialised_header;
s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
s->d1->next_handshake_write_seq++;
dtls1_set_message_header(s, htype, len, s->d1->handshake_write_seq, 0, len);
s->init_num = (int)len + DTLS1_HM_HEADER_LENGTH;
s->init_off = 0;
/* Buffer the message to handle re-xmits */
dtls1_buffer_message(s, 0);
/* Add the new message to the handshake hash. Serialize the message
* header as if it were a single fragment. */
*p++ = msg_hdr->type;
l2n3(msg_hdr->msg_len, p);
s2n(msg_hdr->seq, p);
l2n3(0, p);
l2n3(msg_hdr->msg_len, p);
return ssl3_finish_mac(s, serialised_header, sizeof(serialised_header)) &&
ssl3_finish_mac(s, message + DTLS1_HM_HEADER_LENGTH, len);
}
int dtls1_handshake_write(SSL *s) {
return dtls1_do_write(s, SSL3_RT_HANDSHAKE, dtls1_use_current_epoch);
}