2 * Copyright 2005-2021 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (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>
14 #include "ssl_local.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);
146 dtls1_clear_queues(s);
147 pqueue_free(s->d1->buffered_messages);
148 pqueue_free(s->d1->sent_messages);
155 int dtls1_clear(SSL *s)
157 pqueue *buffered_messages;
158 pqueue *sent_messages;
162 DTLS_RECORD_LAYER_clear(&s->rlayer);
165 DTLS_timer_cb timer_cb = s->d1->timer_cb;
167 buffered_messages = s->d1->buffered_messages;
168 sent_messages = s->d1->sent_messages;
170 link_mtu = s->d1->link_mtu;
172 dtls1_clear_queues(s);
174 memset(s->d1, 0, sizeof(*s->d1));
176 /* Restore the timer callback from previous state */
177 s->d1->timer_cb = timer_cb;
180 s->d1->cookie_len = sizeof(s->d1->cookie);
183 if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) {
185 s->d1->link_mtu = link_mtu;
188 s->d1->buffered_messages = buffered_messages;
189 s->d1->sent_messages = sent_messages;
195 if (s->method->version == DTLS_ANY_VERSION)
196 s->version = DTLS_MAX_VERSION_INTERNAL;
197 #ifndef OPENSSL_NO_DTLS1_METHOD
198 else if (s->options & SSL_OP_CISCO_ANYCONNECT)
199 s->client_version = s->version = DTLS1_BAD_VER;
202 s->version = s->method->version;
207 long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
212 case DTLS_CTRL_GET_TIMEOUT:
213 if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) {
217 case DTLS_CTRL_HANDLE_TIMEOUT:
218 ret = dtls1_handle_timeout(s);
220 case DTLS_CTRL_SET_LINK_MTU:
221 if (larg < (long)dtls1_link_min_mtu())
223 s->d1->link_mtu = larg;
225 case DTLS_CTRL_GET_LINK_MIN_MTU:
226 return (long)dtls1_link_min_mtu();
227 case SSL_CTRL_SET_MTU:
229 * We may not have a BIO set yet so can't call dtls1_min_mtu()
230 * We'll have to make do with dtls1_link_min_mtu() and max overhead
232 if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD)
237 ret = ssl3_ctrl(s, cmd, larg, parg);
243 void dtls1_start_timer(SSL *s)
245 unsigned int sec, usec;
247 #ifndef OPENSSL_NO_SCTP
248 /* Disable timer for SCTP */
249 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
250 memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
256 * If timer is not set, initialize duration with 1 second or
257 * a user-specified value if the timer callback is installed.
259 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
261 if (s->d1->timer_cb != NULL)
262 s->d1->timeout_duration_us = s->d1->timer_cb(s, 0);
264 s->d1->timeout_duration_us = 1000000;
267 /* Set timeout to current time */
268 get_current_time(&(s->d1->next_timeout));
270 /* Add duration to current time */
272 sec = s->d1->timeout_duration_us / 1000000;
273 usec = s->d1->timeout_duration_us - (sec * 1000000);
275 s->d1->next_timeout.tv_sec += sec;
276 s->d1->next_timeout.tv_usec += usec;
278 if (s->d1->next_timeout.tv_usec >= 1000000) {
279 s->d1->next_timeout.tv_sec++;
280 s->d1->next_timeout.tv_usec -= 1000000;
283 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
284 &(s->d1->next_timeout));
287 struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft)
289 struct timeval timenow;
291 /* If no timeout is set, just return NULL */
292 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
296 /* Get current time */
297 get_current_time(&timenow);
299 /* If timer already expired, set remaining time to 0 */
300 if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
301 (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
302 s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
303 memset(timeleft, 0, sizeof(*timeleft));
307 /* Calculate time left until timer expires */
308 memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
309 timeleft->tv_sec -= timenow.tv_sec;
310 timeleft->tv_usec -= timenow.tv_usec;
311 if (timeleft->tv_usec < 0) {
313 timeleft->tv_usec += 1000000;
317 * If remaining time is less than 15 ms, set it to 0 to prevent issues
318 * because of small divergences with socket timeouts.
320 if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
321 memset(timeleft, 0, sizeof(*timeleft));
327 int dtls1_is_timer_expired(SSL *s)
329 struct timeval timeleft;
331 /* Get time left until timeout, return false if no timer running */
332 if (dtls1_get_timeout(s, &timeleft) == NULL) {
336 /* Return false if timer is not expired yet */
337 if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
341 /* Timer expired, so return true */
345 static void dtls1_double_timeout(SSL *s)
347 s->d1->timeout_duration_us *= 2;
348 if (s->d1->timeout_duration_us > 60000000)
349 s->d1->timeout_duration_us = 60000000;
352 void dtls1_stop_timer(SSL *s)
354 /* Reset everything */
355 s->d1->timeout_num_alerts = 0;
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 SSLfatal(s, SSL_AD_NO_ALERT, 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) {
401 /* SSLfatal() already called */
405 dtls1_start_timer(s);
406 /* Calls SSLfatal() if required */
407 return dtls1_retransmit_buffered_messages(s);
410 static void get_current_time(struct timeval *t)
420 SystemTimeToFileTime(&st, &now.ft);
421 /* re-bias to 1/1/1970 */
423 now.ul -= 116444736000000000ULL;
426 now.ul -= 116444736000000000UI64;
429 t->tv_sec = (long)(now.ul / 10000000);
430 t->tv_usec = ((int)(now.ul % 10000000)) / 10;
432 gettimeofday(t, NULL);
436 #define LISTEN_SUCCESS 2
437 #define LISTEN_SEND_VERIFY_REQUEST 1
439 #ifndef OPENSSL_NO_SOCK
440 int DTLSv1_listen(SSL *s, BIO_ADDR *client)
442 int next, n, ret = 0;
443 unsigned char cookie[DTLS1_COOKIE_LENGTH];
444 unsigned char seq[SEQ_NUM_SIZE];
445 const unsigned char *data;
446 unsigned char *buf, *wbuf;
447 size_t fragoff, fraglen, msglen, reclen, align = 0;
448 unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen;
450 BIO_ADDR *tmpclient = NULL;
451 PACKET pkt, msgpkt, msgpayload, session, cookiepkt;
453 if (s->handshake_func == NULL) {
454 /* Not properly initialized yet */
455 SSL_set_accept_state(s);
458 /* Ensure there is no state left over from a previous invocation */
464 rbio = SSL_get_rbio(s);
465 wbio = SSL_get_wbio(s);
467 if (!rbio || !wbio) {
468 ERR_raise(ERR_LIB_SSL, SSL_R_BIO_NOT_SET);
473 * Note: This check deliberately excludes DTLS1_BAD_VER because that version
474 * requires the MAC to be calculated *including* the first ClientHello
475 * (without the cookie). Since DTLSv1_listen is stateless that cannot be
476 * supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via
479 if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
480 ERR_raise(ERR_LIB_SSL, SSL_R_UNSUPPORTED_SSL_VERSION);
484 if (!ssl3_setup_buffers(s)) {
485 /* ERR_raise() already called */
488 buf = RECORD_LAYER_get_rbuf(&s->rlayer)->buf;
489 wbuf = RECORD_LAYER_get_wbuf(&s->rlayer)[0].buf;
490 #if defined(SSL3_ALIGN_PAYLOAD)
491 # if SSL3_ALIGN_PAYLOAD != 0
493 * Using SSL3_RT_HEADER_LENGTH here instead of DTLS1_RT_HEADER_LENGTH for
494 * consistency with ssl3_read_n. In practice it should make no difference
495 * for sensible values of SSL3_ALIGN_PAYLOAD because the difference between
496 * SSL3_RT_HEADER_LENGTH and DTLS1_RT_HEADER_LENGTH is exactly 8
498 align = (size_t)buf + SSL3_RT_HEADER_LENGTH;
499 align = SSL3_ALIGN_PAYLOAD - 1 - ((align - 1) % SSL3_ALIGN_PAYLOAD);
508 n = BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH
509 + DTLS1_RT_HEADER_LENGTH);
511 if (BIO_should_retry(rbio)) {
512 /* Non-blocking IO */
518 if (!PACKET_buf_init(&pkt, buf, n)) {
519 ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
524 * Parse the received record. If there are any problems with it we just
525 * dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is
526 * resilient in the face of invalid records (e.g., invalid formatting,
527 * length, MAC, etc.). In general, invalid records SHOULD be silently
528 * discarded, thus preserving the association; however, an error MAY be
529 * logged for diagnostic purposes."
532 /* this packet contained a partial record, dump it */
533 if (n < DTLS1_RT_HEADER_LENGTH) {
534 ERR_raise(ERR_LIB_SSL, SSL_R_RECORD_TOO_SMALL);
539 s->msg_callback(0, 0, SSL3_RT_HEADER, buf,
540 DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
542 /* Get the record header */
543 if (!PACKET_get_1(&pkt, &rectype)
544 || !PACKET_get_1(&pkt, &versmajor)) {
545 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
549 if (rectype != SSL3_RT_HANDSHAKE) {
550 ERR_raise(ERR_LIB_SSL, SSL_R_UNEXPECTED_MESSAGE);
555 * Check record version number. We only check that the major version is
558 if (versmajor != DTLS1_VERSION_MAJOR) {
559 ERR_raise(ERR_LIB_SSL, SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
563 if (!PACKET_forward(&pkt, 1)
564 /* Save the sequence number: 64 bits, with top 2 bytes = epoch */
565 || !PACKET_copy_bytes(&pkt, seq, SEQ_NUM_SIZE)
566 || !PACKET_get_length_prefixed_2(&pkt, &msgpkt)) {
567 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
570 reclen = PACKET_remaining(&msgpkt);
572 * We allow data remaining at the end of the packet because there could
573 * be a second record (but we ignore it)
576 /* This is an initial ClientHello so the epoch has to be 0 */
577 if (seq[0] != 0 || seq[1] != 0) {
578 ERR_raise(ERR_LIB_SSL, SSL_R_UNEXPECTED_MESSAGE);
582 /* Get a pointer to the raw message for the later callback */
583 data = PACKET_data(&msgpkt);
585 /* Finished processing the record header, now process the message */
586 if (!PACKET_get_1(&msgpkt, &msgtype)
587 || !PACKET_get_net_3_len(&msgpkt, &msglen)
588 || !PACKET_get_net_2(&msgpkt, &msgseq)
589 || !PACKET_get_net_3_len(&msgpkt, &fragoff)
590 || !PACKET_get_net_3_len(&msgpkt, &fraglen)
591 || !PACKET_get_sub_packet(&msgpkt, &msgpayload, fraglen)
592 || PACKET_remaining(&msgpkt) != 0) {
593 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
597 if (msgtype != SSL3_MT_CLIENT_HELLO) {
598 ERR_raise(ERR_LIB_SSL, SSL_R_UNEXPECTED_MESSAGE);
602 /* Message sequence number can only be 0 or 1 */
604 ERR_raise(ERR_LIB_SSL, SSL_R_INVALID_SEQUENCE_NUMBER);
609 * We don't support fragment reassembly for ClientHellos whilst
610 * listening because that would require server side state (which is
611 * against the whole point of the ClientHello/HelloVerifyRequest
612 * mechanism). Instead we only look at the first ClientHello fragment
613 * and require that the cookie must be contained within it.
615 if (fragoff != 0 || fraglen > msglen) {
616 /* Non initial ClientHello fragment (or bad fragment) */
617 ERR_raise(ERR_LIB_SSL, SSL_R_FRAGMENTED_CLIENT_HELLO);
622 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, data,
623 fraglen + DTLS1_HM_HEADER_LENGTH, s,
624 s->msg_callback_arg);
626 if (!PACKET_get_net_2(&msgpayload, &clientvers)) {
627 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
632 * Verify client version is supported
634 if (DTLS_VERSION_LT(clientvers, (unsigned int)s->method->version) &&
635 s->method->version != DTLS_ANY_VERSION) {
636 ERR_raise(ERR_LIB_SSL, SSL_R_WRONG_VERSION_NUMBER);
640 if (!PACKET_forward(&msgpayload, SSL3_RANDOM_SIZE)
641 || !PACKET_get_length_prefixed_1(&msgpayload, &session)
642 || !PACKET_get_length_prefixed_1(&msgpayload, &cookiepkt)) {
644 * Could be malformed or the cookie does not fit within the initial
645 * ClientHello fragment. Either way we can't handle it.
647 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
652 * Check if we have a cookie or not. If not we need to send a
653 * HelloVerifyRequest.
655 if (PACKET_remaining(&cookiepkt) == 0) {
656 next = LISTEN_SEND_VERIFY_REQUEST;
659 * We have a cookie, so lets check it.
661 if (s->ctx->app_verify_cookie_cb == NULL) {
662 ERR_raise(ERR_LIB_SSL, SSL_R_NO_VERIFY_COOKIE_CALLBACK);
666 if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&cookiepkt),
667 (unsigned int)PACKET_remaining(&cookiepkt)) == 0) {
669 * We treat invalid cookies in the same was as no cookie as
672 next = LISTEN_SEND_VERIFY_REQUEST;
674 /* Cookie verification succeeded */
675 next = LISTEN_SUCCESS;
679 if (next == LISTEN_SEND_VERIFY_REQUEST) {
681 unsigned int version;
685 * There was no cookie in the ClientHello so we need to send a
686 * HelloVerifyRequest. If this fails we do not worry about trying
687 * to resend, we just drop it.
690 /* Generate the cookie */
691 if (s->ctx->app_gen_cookie_cb == NULL ||
692 s->ctx->app_gen_cookie_cb(s, cookie, &cookielen) == 0 ||
694 ERR_raise(ERR_LIB_SSL, SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
700 * Special case: for hello verify request, client version 1.0 and we
701 * haven't decided which version to use yet send back using version
702 * 1.0 header: otherwise some clients will ignore it.
704 version = (s->method->version == DTLS_ANY_VERSION) ? DTLS1_VERSION
707 /* Construct the record and message headers */
708 if (!WPACKET_init_static_len(&wpkt,
710 ssl_get_max_send_fragment(s)
711 + DTLS1_RT_HEADER_LENGTH,
713 || !WPACKET_put_bytes_u8(&wpkt, SSL3_RT_HANDSHAKE)
714 || !WPACKET_put_bytes_u16(&wpkt, version)
716 * Record sequence number is always the same as in the
717 * received ClientHello
719 || !WPACKET_memcpy(&wpkt, seq, SEQ_NUM_SIZE)
720 /* End of record, start sub packet for message */
721 || !WPACKET_start_sub_packet_u16(&wpkt)
723 || !WPACKET_put_bytes_u8(&wpkt,
724 DTLS1_MT_HELLO_VERIFY_REQUEST)
726 * Message length - doesn't follow normal TLS convention:
727 * the length isn't the last thing in the message header.
728 * We'll need to fill this in later when we know the
729 * length. Set it to zero for now
731 || !WPACKET_put_bytes_u24(&wpkt, 0)
733 * Message sequence number is always 0 for a
736 || !WPACKET_put_bytes_u16(&wpkt, 0)
738 * We never fragment a HelloVerifyRequest, so fragment
741 || !WPACKET_put_bytes_u24(&wpkt, 0)
743 * Fragment length is the same as message length, but
744 * this *is* the last thing in the message header so we
745 * can just start a sub-packet. No need to come back
746 * later for this one.
748 || !WPACKET_start_sub_packet_u24(&wpkt)
749 /* Create the actual HelloVerifyRequest body */
750 || !dtls_raw_hello_verify_request(&wpkt, cookie, cookielen)
751 /* Close message body */
752 || !WPACKET_close(&wpkt)
753 /* Close record body */
754 || !WPACKET_close(&wpkt)
755 || !WPACKET_get_total_written(&wpkt, &wreclen)
756 || !WPACKET_finish(&wpkt)) {
757 ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
758 WPACKET_cleanup(&wpkt);
764 * Fix up the message len in the message header. Its the same as the
765 * fragment len which has been filled in by WPACKET, so just copy
766 * that. Destination for the message len is after the record header
767 * plus one byte for the message content type. The source is the
768 * last 3 bytes of the message header
770 memcpy(&wbuf[DTLS1_RT_HEADER_LENGTH + 1],
771 &wbuf[DTLS1_RT_HEADER_LENGTH + DTLS1_HM_HEADER_LENGTH - 3],
775 s->msg_callback(1, 0, SSL3_RT_HEADER, buf,
776 DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
778 if ((tmpclient = BIO_ADDR_new()) == NULL) {
779 ERR_raise(ERR_LIB_SSL, ERR_R_MALLOC_FAILURE);
784 * This is unnecessary if rbio and wbio are one and the same - but
785 * maybe they're not. We ignore errors here - some BIOs do not
788 if (BIO_dgram_get_peer(rbio, tmpclient) > 0) {
789 (void)BIO_dgram_set_peer(wbio, tmpclient);
791 BIO_ADDR_free(tmpclient);
794 if (BIO_write(wbio, wbuf, wreclen) < (int)wreclen) {
795 if (BIO_should_retry(wbio)) {
797 * Non-blocking IO...but we're stateless, so we're just
798 * going to drop this packet.
805 if (BIO_flush(wbio) <= 0) {
806 if (BIO_should_retry(wbio)) {
808 * Non-blocking IO...but we're stateless, so we're just
809 * going to drop this packet.
816 } while (next != LISTEN_SUCCESS);
819 * Set expected sequence numbers to continue the handshake.
821 s->d1->handshake_read_seq = 1;
822 s->d1->handshake_write_seq = 1;
823 s->d1->next_handshake_write_seq = 1;
824 DTLS_RECORD_LAYER_set_write_sequence(&s->rlayer, seq);
827 * We are doing cookie exchange, so make sure we set that option in the
830 SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
833 * Tell the state machine that we've done the initial hello verify
836 ossl_statem_set_hello_verify_done(s);
839 * Some BIOs may not support this. If we fail we clear the client address
841 if (BIO_dgram_get_peer(rbio, client) <= 0)
842 BIO_ADDR_clear(client);
844 /* Buffer the record in the processed_rcds queue */
845 if (!dtls_buffer_listen_record(s, reclen, seq, align))
850 BIO_ADDR_free(tmpclient);
855 static int dtls1_handshake_write(SSL *s)
857 return dtls1_do_write(s, SSL3_RT_HANDSHAKE);
860 int dtls1_shutdown(SSL *s)
863 #ifndef OPENSSL_NO_SCTP
866 wbio = SSL_get_wbio(s);
867 if (wbio != NULL && BIO_dgram_is_sctp(wbio) &&
868 !(s->shutdown & SSL_SENT_SHUTDOWN)) {
869 ret = BIO_dgram_sctp_wait_for_dry(wbio);
874 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1,
878 ret = ssl3_shutdown(s);
879 #ifndef OPENSSL_NO_SCTP
880 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
885 int dtls1_query_mtu(SSL *s)
887 if (s->d1->link_mtu) {
889 s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
893 /* AHA! Figure out the MTU, and stick to the right size */
894 if (s->d1->mtu < dtls1_min_mtu(s)) {
895 if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
897 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
900 * I've seen the kernel return bogus numbers when it doesn't know
901 * (initial write), so just make sure we have a reasonable number
903 if (s->d1->mtu < dtls1_min_mtu(s)) {
905 s->d1->mtu = dtls1_min_mtu(s);
906 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
907 (long)s->d1->mtu, NULL);
915 static size_t dtls1_link_min_mtu(void)
917 return (g_probable_mtu[(sizeof(g_probable_mtu) /
918 sizeof(g_probable_mtu[0])) - 1]);
921 size_t dtls1_min_mtu(SSL *s)
923 return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
926 size_t DTLS_get_data_mtu(const SSL *s)
928 size_t mac_overhead, int_overhead, blocksize, ext_overhead;
929 const SSL_CIPHER *ciph = SSL_get_current_cipher(s);
930 size_t mtu = s->d1->mtu;
935 if (!ssl_cipher_get_overhead(ciph, &mac_overhead, &int_overhead,
936 &blocksize, &ext_overhead))
940 ext_overhead += mac_overhead;
942 int_overhead += mac_overhead;
944 /* Subtract external overhead (e.g. IV/nonce, separate MAC) */
945 if (ext_overhead + DTLS1_RT_HEADER_LENGTH >= mtu)
947 mtu -= ext_overhead + DTLS1_RT_HEADER_LENGTH;
949 /* Round encrypted payload down to cipher block size (for CBC etc.)
950 * No check for overflow since 'mtu % blocksize' cannot exceed mtu. */
952 mtu -= (mtu % blocksize);
954 /* Subtract internal overhead (e.g. CBC padding len byte) */
955 if (int_overhead >= mtu)
962 void DTLS_set_timer_cb(SSL *s, DTLS_timer_cb cb)
964 s->d1->timer_cb = cb;