- /*
- * 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, 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_update_handshake_hash(s, serialised_header,
- sizeof(serialised_header)) &&
- ssl3_update_handshake_hash(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);
- }
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