2 * Copyright 2005-2017 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
12 #include <openssl/objects.h>
13 #include <openssl/rand.h>
16 static void get_current_time(struct timeval *t);
17 static int dtls1_handshake_write(SSL *s);
18 static size_t dtls1_link_min_mtu(void);
20 /* XDTLS: figure out the right values */
21 static const size_t g_probable_mtu[] = { 1500, 512, 256 };
23 const SSL3_ENC_METHOD DTLSv1_enc_data = {
27 tls1_generate_master_secret,
28 tls1_change_cipher_state,
29 tls1_final_finish_mac,
30 TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
31 TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
33 tls1_export_keying_material,
34 SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV,
35 dtls1_set_handshake_header,
36 dtls1_close_construct_packet,
40 const SSL3_ENC_METHOD DTLSv1_2_enc_data = {
44 tls1_generate_master_secret,
45 tls1_change_cipher_state,
46 tls1_final_finish_mac,
47 TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
48 TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
50 tls1_export_keying_material,
51 SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV | SSL_ENC_FLAG_SIGALGS
52 | SSL_ENC_FLAG_SHA256_PRF | SSL_ENC_FLAG_TLS1_2_CIPHERS,
53 dtls1_set_handshake_header,
54 dtls1_close_construct_packet,
58 long dtls1_default_timeout(void)
61 * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for
62 * http, the cache would over fill
71 if (!DTLS_RECORD_LAYER_new(&s->rlayer)) {
77 if ((d1 = OPENSSL_zalloc(sizeof(*d1))) == NULL) {
82 d1->buffered_messages = pqueue_new();
83 d1->sent_messages = pqueue_new();
86 d1->cookie_len = sizeof(s->d1->cookie);
92 if (d1->buffered_messages == NULL || d1->sent_messages == NULL) {
93 pqueue_free(d1->buffered_messages);
94 pqueue_free(d1->sent_messages);
102 if (!s->method->ssl_clear(s))
108 static void dtls1_clear_queues(SSL *s)
110 dtls1_clear_received_buffer(s);
111 dtls1_clear_sent_buffer(s);
114 void dtls1_clear_received_buffer(SSL *s)
117 hm_fragment *frag = NULL;
119 while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) {
120 frag = (hm_fragment *)item->data;
121 dtls1_hm_fragment_free(frag);
126 void dtls1_clear_sent_buffer(SSL *s)
129 hm_fragment *frag = NULL;
131 while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) {
132 frag = (hm_fragment *)item->data;
133 dtls1_hm_fragment_free(frag);
139 void dtls1_free(SSL *s)
141 DTLS_RECORD_LAYER_free(&s->rlayer);
145 dtls1_clear_queues(s);
147 pqueue_free(s->d1->buffered_messages);
148 pqueue_free(s->d1->sent_messages);
154 int dtls1_clear(SSL *s)
156 pqueue *buffered_messages;
157 pqueue *sent_messages;
161 DTLS_RECORD_LAYER_clear(&s->rlayer);
164 DTLS_timer_cb timer_cb = s->d1->timer_cb;
166 buffered_messages = s->d1->buffered_messages;
167 sent_messages = s->d1->sent_messages;
169 link_mtu = s->d1->link_mtu;
171 dtls1_clear_queues(s);
173 memset(s->d1, 0, sizeof(*s->d1));
175 /* Restore the timer callback from previous state */
176 s->d1->timer_cb = timer_cb;
179 s->d1->cookie_len = sizeof(s->d1->cookie);
182 if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) {
184 s->d1->link_mtu = link_mtu;
187 s->d1->buffered_messages = buffered_messages;
188 s->d1->sent_messages = sent_messages;
194 if (s->method->version == DTLS_ANY_VERSION)
195 s->version = DTLS_MAX_VERSION;
196 #ifndef OPENSSL_NO_DTLS1_METHOD
197 else if (s->options & SSL_OP_CISCO_ANYCONNECT)
198 s->client_version = s->version = DTLS1_BAD_VER;
201 s->version = s->method->version;
206 long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
211 case DTLS_CTRL_GET_TIMEOUT:
212 if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) {
216 case DTLS_CTRL_HANDLE_TIMEOUT:
217 ret = dtls1_handle_timeout(s);
219 case DTLS_CTRL_SET_LINK_MTU:
220 if (larg < (long)dtls1_link_min_mtu())
222 s->d1->link_mtu = larg;
224 case DTLS_CTRL_GET_LINK_MIN_MTU:
225 return (long)dtls1_link_min_mtu();
226 case SSL_CTRL_SET_MTU:
228 * We may not have a BIO set yet so can't call dtls1_min_mtu()
229 * We'll have to make do with dtls1_link_min_mtu() and max overhead
231 if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD)
236 ret = ssl3_ctrl(s, cmd, larg, parg);
242 void dtls1_start_timer(SSL *s)
244 unsigned int sec, usec;
246 #ifndef OPENSSL_NO_SCTP
247 /* Disable timer for SCTP */
248 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
249 memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
255 * If timer is not set, initialize duration with 1 second or
256 * a user-specified value if the timer callback is installed.
258 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
260 if (s->d1->timer_cb != NULL)
261 s->d1->timeout_duration_us = s->d1->timer_cb(s, 0);
263 s->d1->timeout_duration_us = 1000000;
266 /* Set timeout to current time */
267 get_current_time(&(s->d1->next_timeout));
269 /* Add duration to current time */
271 sec = s->d1->timeout_duration_us / 1000000;
272 usec = s->d1->timeout_duration_us - (sec * 1000000);
274 s->d1->next_timeout.tv_sec += sec;
275 s->d1->next_timeout.tv_usec += usec;
277 if (s->d1->next_timeout.tv_usec >= 1000000) {
278 s->d1->next_timeout.tv_sec++;
279 s->d1->next_timeout.tv_usec -= 1000000;
282 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
283 &(s->d1->next_timeout));
286 struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft)
288 struct timeval timenow;
290 /* If no timeout is set, just return NULL */
291 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
295 /* Get current time */
296 get_current_time(&timenow);
298 /* If timer already expired, set remaining time to 0 */
299 if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
300 (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
301 s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
302 memset(timeleft, 0, sizeof(*timeleft));
306 /* Calculate time left until timer expires */
307 memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
308 timeleft->tv_sec -= timenow.tv_sec;
309 timeleft->tv_usec -= timenow.tv_usec;
310 if (timeleft->tv_usec < 0) {
312 timeleft->tv_usec += 1000000;
316 * If remaining time is less than 15 ms, set it to 0 to prevent issues
317 * because of small divergences with socket timeouts.
319 if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
320 memset(timeleft, 0, sizeof(*timeleft));
326 int dtls1_is_timer_expired(SSL *s)
328 struct timeval timeleft;
330 /* Get time left until timeout, return false if no timer running */
331 if (dtls1_get_timeout(s, &timeleft) == NULL) {
335 /* Return false if timer is not expired yet */
336 if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
340 /* Timer expired, so return true */
344 void dtls1_double_timeout(SSL *s)
346 s->d1->timeout_duration_us *= 2;
347 if (s->d1->timeout_duration_us > 60000000)
348 s->d1->timeout_duration_us = 60000000;
349 dtls1_start_timer(s);
352 void dtls1_stop_timer(SSL *s)
354 /* Reset everything */
355 memset(&s->d1->timeout, 0, sizeof(s->d1->timeout));
356 memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
357 s->d1->timeout_duration_us = 1000000;
358 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
359 &(s->d1->next_timeout));
360 /* Clear retransmission buffer */
361 dtls1_clear_sent_buffer(s);
364 int dtls1_check_timeout_num(SSL *s)
368 s->d1->timeout.num_alerts++;
370 /* Reduce MTU after 2 unsuccessful retransmissions */
371 if (s->d1->timeout.num_alerts > 2
372 && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
374 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL);
375 if (mtu < s->d1->mtu)
379 if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) {
380 /* fail the connection, enough alerts have been sent */
381 SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM, SSL_R_READ_TIMEOUT_EXPIRED);
388 int dtls1_handle_timeout(SSL *s)
390 /* if no timer is expired, don't do anything */
391 if (!dtls1_is_timer_expired(s)) {
395 if (s->d1->timer_cb != NULL)
396 s->d1->timeout_duration_us = s->d1->timer_cb(s, s->d1->timeout_duration_us);
398 dtls1_double_timeout(s);
400 if (dtls1_check_timeout_num(s) < 0)
403 s->d1->timeout.read_timeouts++;
404 if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) {
405 s->d1->timeout.read_timeouts = 1;
408 dtls1_start_timer(s);
409 return dtls1_retransmit_buffered_messages(s);
412 static void get_current_time(struct timeval *t)
422 SystemTimeToFileTime(&st, &now.ft);
423 /* re-bias to 1/1/1970 */
425 now.ul -= 116444736000000000ULL;
428 now.ul -= 116444736000000000UI64;
431 t->tv_sec = (long)(now.ul / 10000000);
432 t->tv_usec = ((int)(now.ul % 10000000)) / 10;
434 gettimeofday(t, NULL);
438 #define LISTEN_SUCCESS 2
439 #define LISTEN_SEND_VERIFY_REQUEST 1
441 #ifndef OPENSSL_NO_SOCK
442 int DTLSv1_listen(SSL *s, BIO_ADDR *client)
444 int next, n, ret = 0, clearpkt = 0;
445 unsigned char cookie[DTLS1_COOKIE_LENGTH];
446 unsigned char seq[SEQ_NUM_SIZE];
447 const unsigned char *data;
449 size_t fragoff, fraglen, msglen;
450 unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen;
453 BIO_ADDR *tmpclient = NULL;
454 PACKET pkt, msgpkt, msgpayload, session, cookiepkt;
456 if (s->handshake_func == NULL) {
457 /* Not properly initialized yet */
458 SSL_set_accept_state(s);
461 /* Ensure there is no state left over from a previous invocation */
467 rbio = SSL_get_rbio(s);
468 wbio = SSL_get_wbio(s);
470 if (!rbio || !wbio) {
471 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BIO_NOT_SET);
476 * We only peek at incoming ClientHello's until we're sure we are going to
477 * to respond with a HelloVerifyRequest. If its a ClientHello with a valid
478 * cookie then we leave it in the BIO for accept to handle.
480 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);
483 * Note: This check deliberately excludes DTLS1_BAD_VER because that version
484 * requires the MAC to be calculated *including* the first ClientHello
485 * (without the cookie). Since DTLSv1_listen is stateless that cannot be
486 * supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via
489 if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
490 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNSUPPORTED_SSL_VERSION);
494 if (s->init_buf == NULL) {
495 if ((bufm = BUF_MEM_new()) == NULL) {
496 SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
500 if (!BUF_MEM_grow(bufm, SSL3_RT_MAX_PLAIN_LENGTH)) {
502 SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
507 buf = (unsigned char *)s->init_buf->data;
514 * Technically a ClientHello could be SSL3_RT_MAX_PLAIN_LENGTH
515 * + DTLS1_RT_HEADER_LENGTH bytes long. Normally init_buf does not store
516 * the record header as well, but we do here. We've set up init_buf to
517 * be the standard size for simplicity. In practice we shouldn't ever
518 * receive a ClientHello as long as this. If we do it will get dropped
519 * in the record length check below.
521 n = BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
524 if (BIO_should_retry(rbio)) {
525 /* Non-blocking IO */
531 /* If we hit any problems we need to clear this packet from the BIO */
534 if (!PACKET_buf_init(&pkt, buf, n)) {
535 SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_INTERNAL_ERROR);
540 * Parse the received record. If there are any problems with it we just
541 * dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is
542 * resilient in the face of invalid records (e.g., invalid formatting,
543 * length, MAC, etc.). In general, invalid records SHOULD be silently
544 * discarded, thus preserving the association; however, an error MAY be
545 * logged for diagnostic purposes."
548 /* this packet contained a partial record, dump it */
549 if (n < DTLS1_RT_HEADER_LENGTH) {
550 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_RECORD_TOO_SMALL);
555 s->msg_callback(0, 0, SSL3_RT_HEADER, buf,
556 DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
558 /* Get the record header */
559 if (!PACKET_get_1(&pkt, &rectype)
560 || !PACKET_get_1(&pkt, &versmajor)) {
561 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
565 if (rectype != SSL3_RT_HANDSHAKE) {
566 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
571 * Check record version number. We only check that the major version is
574 if (versmajor != DTLS1_VERSION_MAJOR) {
575 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
579 if (!PACKET_forward(&pkt, 1)
580 /* Save the sequence number: 64 bits, with top 2 bytes = epoch */
581 || !PACKET_copy_bytes(&pkt, seq, SEQ_NUM_SIZE)
582 || !PACKET_get_length_prefixed_2(&pkt, &msgpkt)) {
583 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
587 * We allow data remaining at the end of the packet because there could
588 * be a second record (but we ignore it)
591 /* This is an initial ClientHello so the epoch has to be 0 */
592 if (seq[0] != 0 || seq[1] != 0) {
593 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
597 /* Get a pointer to the raw message for the later callback */
598 data = PACKET_data(&msgpkt);
600 /* Finished processing the record header, now process the message */
601 if (!PACKET_get_1(&msgpkt, &msgtype)
602 || !PACKET_get_net_3_len(&msgpkt, &msglen)
603 || !PACKET_get_net_2(&msgpkt, &msgseq)
604 || !PACKET_get_net_3_len(&msgpkt, &fragoff)
605 || !PACKET_get_net_3_len(&msgpkt, &fraglen)
606 || !PACKET_get_sub_packet(&msgpkt, &msgpayload, fraglen)
607 || PACKET_remaining(&msgpkt) != 0) {
608 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
612 if (msgtype != SSL3_MT_CLIENT_HELLO) {
613 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
617 /* Message sequence number can only be 0 or 1 */
619 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_INVALID_SEQUENCE_NUMBER);
624 * We don't support fragment reassembly for ClientHellos whilst
625 * listening because that would require server side state (which is
626 * against the whole point of the ClientHello/HelloVerifyRequest
627 * mechanism). Instead we only look at the first ClientHello fragment
628 * and require that the cookie must be contained within it.
630 if (fragoff != 0 || fraglen > msglen) {
631 /* Non initial ClientHello fragment (or bad fragment) */
632 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_FRAGMENTED_CLIENT_HELLO);
637 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, data,
638 fraglen + DTLS1_HM_HEADER_LENGTH, s,
639 s->msg_callback_arg);
641 if (!PACKET_get_net_2(&msgpayload, &clientvers)) {
642 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
647 * Verify client version is supported
649 if (DTLS_VERSION_LT(clientvers, (unsigned int)s->method->version) &&
650 s->method->version != DTLS_ANY_VERSION) {
651 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_WRONG_VERSION_NUMBER);
655 if (!PACKET_forward(&msgpayload, SSL3_RANDOM_SIZE)
656 || !PACKET_get_length_prefixed_1(&msgpayload, &session)
657 || !PACKET_get_length_prefixed_1(&msgpayload, &cookiepkt)) {
659 * Could be malformed or the cookie does not fit within the initial
660 * ClientHello fragment. Either way we can't handle it.
662 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
667 * Check if we have a cookie or not. If not we need to send a
668 * HelloVerifyRequest.
670 if (PACKET_remaining(&cookiepkt) == 0) {
671 next = LISTEN_SEND_VERIFY_REQUEST;
674 * We have a cookie, so lets check it.
676 if (s->ctx->app_verify_cookie_cb == NULL) {
677 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_NO_VERIFY_COOKIE_CALLBACK);
681 if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&cookiepkt),
682 (unsigned int)PACKET_remaining(&cookiepkt)) == 0) {
684 * We treat invalid cookies in the same was as no cookie as
687 next = LISTEN_SEND_VERIFY_REQUEST;
689 /* Cookie verification succeeded */
690 next = LISTEN_SUCCESS;
694 if (next == LISTEN_SEND_VERIFY_REQUEST) {
696 unsigned int version;
700 * There was no cookie in the ClientHello so we need to send a
701 * HelloVerifyRequest. If this fails we do not worry about trying
702 * to resend, we just drop it.
706 * Dump the read packet, we don't need it any more. Ignore return
709 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL);
710 BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
711 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);
713 /* Generate the cookie */
714 if (s->ctx->app_gen_cookie_cb == NULL ||
715 s->ctx->app_gen_cookie_cb(s, cookie, &cookielen) == 0 ||
717 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
723 * Special case: for hello verify request, client version 1.0 and we
724 * haven't decided which version to use yet send back using version
725 * 1.0 header: otherwise some clients will ignore it.
727 version = (s->method->version == DTLS_ANY_VERSION) ? DTLS1_VERSION
730 /* Construct the record and message headers */
731 if (!WPACKET_init(&wpkt, s->init_buf)
732 || !WPACKET_put_bytes_u8(&wpkt, SSL3_RT_HANDSHAKE)
733 || !WPACKET_put_bytes_u16(&wpkt, version)
735 * Record sequence number is always the same as in the
736 * received ClientHello
738 || !WPACKET_memcpy(&wpkt, seq, SEQ_NUM_SIZE)
739 /* End of record, start sub packet for message */
740 || !WPACKET_start_sub_packet_u16(&wpkt)
742 || !WPACKET_put_bytes_u8(&wpkt,
743 DTLS1_MT_HELLO_VERIFY_REQUEST)
745 * Message length - doesn't follow normal TLS convention:
746 * the length isn't the last thing in the message header.
747 * We'll need to fill this in later when we know the
748 * length. Set it to zero for now
750 || !WPACKET_put_bytes_u24(&wpkt, 0)
752 * Message sequence number is always 0 for a
755 || !WPACKET_put_bytes_u16(&wpkt, 0)
757 * We never fragment a HelloVerifyRequest, so fragment
760 || !WPACKET_put_bytes_u24(&wpkt, 0)
762 * Fragment length is the same as message length, but
763 * this *is* the last thing in the message header so we
764 * can just start a sub-packet. No need to come back
765 * later for this one.
767 || !WPACKET_start_sub_packet_u24(&wpkt)
768 /* Create the actual HelloVerifyRequest body */
769 || !dtls_raw_hello_verify_request(&wpkt, cookie, cookielen)
770 /* Close message body */
771 || !WPACKET_close(&wpkt)
772 /* Close record body */
773 || !WPACKET_close(&wpkt)
774 || !WPACKET_get_total_written(&wpkt, &wreclen)
775 || !WPACKET_finish(&wpkt)) {
776 SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_INTERNAL_ERROR);
777 WPACKET_cleanup(&wpkt);
783 * Fix up the message len in the message header. Its the same as the
784 * fragment len which has been filled in by WPACKET, so just copy
785 * that. Destination for the message len is after the record header
786 * plus one byte for the message content type. The source is the
787 * last 3 bytes of the message header
789 memcpy(&buf[DTLS1_RT_HEADER_LENGTH + 1],
790 &buf[DTLS1_RT_HEADER_LENGTH + DTLS1_HM_HEADER_LENGTH - 3],
794 s->msg_callback(1, 0, SSL3_RT_HEADER, buf,
795 DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
797 if ((tmpclient = BIO_ADDR_new()) == NULL) {
798 SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
803 * This is unnecessary if rbio and wbio are one and the same - but
804 * maybe they're not. We ignore errors here - some BIOs do not
807 if (BIO_dgram_get_peer(rbio, tmpclient) > 0) {
808 (void)BIO_dgram_set_peer(wbio, tmpclient);
810 BIO_ADDR_free(tmpclient);
813 /* TODO(size_t): convert this call */
814 if (BIO_write(wbio, buf, wreclen) < (int)wreclen) {
815 if (BIO_should_retry(wbio)) {
817 * Non-blocking IO...but we're stateless, so we're just
818 * going to drop this packet.
825 if (BIO_flush(wbio) <= 0) {
826 if (BIO_should_retry(wbio)) {
828 * Non-blocking IO...but we're stateless, so we're just
829 * going to drop this packet.
836 } while (next != LISTEN_SUCCESS);
839 * Set expected sequence numbers to continue the handshake.
841 s->d1->handshake_read_seq = 1;
842 s->d1->handshake_write_seq = 1;
843 s->d1->next_handshake_write_seq = 1;
844 DTLS_RECORD_LAYER_set_write_sequence(&s->rlayer, seq);
847 * We are doing cookie exchange, so make sure we set that option in the
850 SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
853 * Tell the state machine that we've done the initial hello verify
856 ossl_statem_set_hello_verify_done(s);
859 * Some BIOs may not support this. If we fail we clear the client address
861 if (BIO_dgram_get_peer(rbio, client) <= 0)
862 BIO_ADDR_clear(client);
867 BIO_ADDR_free(tmpclient);
868 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL);
870 /* Dump this packet. Ignore return value */
871 BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
877 static int dtls1_handshake_write(SSL *s)
879 return dtls1_do_write(s, SSL3_RT_HANDSHAKE);
882 int dtls1_shutdown(SSL *s)
885 #ifndef OPENSSL_NO_SCTP
888 wbio = SSL_get_wbio(s);
889 if (wbio != NULL && BIO_dgram_is_sctp(wbio) &&
890 !(s->shutdown & SSL_SENT_SHUTDOWN)) {
891 ret = BIO_dgram_sctp_wait_for_dry(wbio);
896 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1,
900 ret = ssl3_shutdown(s);
901 #ifndef OPENSSL_NO_SCTP
902 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
907 int dtls1_query_mtu(SSL *s)
909 if (s->d1->link_mtu) {
911 s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
915 /* AHA! Figure out the MTU, and stick to the right size */
916 if (s->d1->mtu < dtls1_min_mtu(s)) {
917 if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
919 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
922 * I've seen the kernel return bogus numbers when it doesn't know
923 * (initial write), so just make sure we have a reasonable number
925 if (s->d1->mtu < dtls1_min_mtu(s)) {
927 s->d1->mtu = dtls1_min_mtu(s);
928 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
929 (long)s->d1->mtu, NULL);
937 static size_t dtls1_link_min_mtu(void)
939 return (g_probable_mtu[(sizeof(g_probable_mtu) /
940 sizeof(g_probable_mtu[0])) - 1]);
943 size_t dtls1_min_mtu(SSL *s)
945 return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
948 size_t DTLS_get_data_mtu(const SSL *s)
950 size_t mac_overhead, int_overhead, blocksize, ext_overhead;
951 const SSL_CIPHER *ciph = SSL_get_current_cipher(s);
952 size_t mtu = s->d1->mtu;
957 if (!ssl_cipher_get_overhead(ciph, &mac_overhead, &int_overhead,
958 &blocksize, &ext_overhead))
962 ext_overhead += mac_overhead;
964 int_overhead += mac_overhead;
966 /* Subtract external overhead (e.g. IV/nonce, separate MAC) */
967 if (ext_overhead + DTLS1_RT_HEADER_LENGTH >= mtu)
969 mtu -= ext_overhead + DTLS1_RT_HEADER_LENGTH;
971 /* Round encrypted payload down to cipher block size (for CBC etc.)
972 * No check for overflow since 'mtu % blocksize' cannot exceed mtu. */
974 mtu -= (mtu % blocksize);
976 /* Subtract internal overhead (e.g. CBC padding len byte) */
977 if (int_overhead >= mtu)
984 void DTLS_set_timer_cb(SSL *s, DTLS_timer_cb cb)
986 s->d1->timer_cb = cb;