2 * Copyright 2005-2022 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
10 #include "internal/e_os.h"
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;
134 if (frag->msg_header.is_ccs) {
136 * If we're freeing the CCS then we're done with the old
137 * enc_write_ctx/write_hash and they can be freed
140 != frag->msg_header.saved_retransmit_state.enc_write_ctx)
141 EVP_CIPHER_CTX_free(frag->msg_header.saved_retransmit_state
145 != frag->msg_header.saved_retransmit_state.write_hash)
146 EVP_MD_CTX_free(frag->msg_header.saved_retransmit_state
150 dtls1_hm_fragment_free(frag);
156 void dtls1_free(SSL *s)
158 DTLS_RECORD_LAYER_free(&s->rlayer);
163 dtls1_clear_queues(s);
164 pqueue_free(s->d1->buffered_messages);
165 pqueue_free(s->d1->sent_messages);
172 int dtls1_clear(SSL *s)
174 pqueue *buffered_messages;
175 pqueue *sent_messages;
179 DTLS_RECORD_LAYER_clear(&s->rlayer);
182 DTLS_timer_cb timer_cb = s->d1->timer_cb;
184 buffered_messages = s->d1->buffered_messages;
185 sent_messages = s->d1->sent_messages;
187 link_mtu = s->d1->link_mtu;
189 dtls1_clear_queues(s);
191 memset(s->d1, 0, sizeof(*s->d1));
193 /* Restore the timer callback from previous state */
194 s->d1->timer_cb = timer_cb;
197 s->d1->cookie_len = sizeof(s->d1->cookie);
200 if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) {
202 s->d1->link_mtu = link_mtu;
205 s->d1->buffered_messages = buffered_messages;
206 s->d1->sent_messages = sent_messages;
212 if (s->method->version == DTLS_ANY_VERSION)
213 s->version = DTLS_MAX_VERSION_INTERNAL;
214 #ifndef OPENSSL_NO_DTLS1_METHOD
215 else if (s->options & SSL_OP_CISCO_ANYCONNECT)
216 s->client_version = s->version = DTLS1_BAD_VER;
219 s->version = s->method->version;
224 long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
229 case DTLS_CTRL_GET_TIMEOUT:
230 if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) {
234 case DTLS_CTRL_HANDLE_TIMEOUT:
235 ret = dtls1_handle_timeout(s);
237 case DTLS_CTRL_SET_LINK_MTU:
238 if (larg < (long)dtls1_link_min_mtu())
240 s->d1->link_mtu = larg;
242 case DTLS_CTRL_GET_LINK_MIN_MTU:
243 return (long)dtls1_link_min_mtu();
244 case SSL_CTRL_SET_MTU:
246 * We may not have a BIO set yet so can't call dtls1_min_mtu()
247 * We'll have to make do with dtls1_link_min_mtu() and max overhead
249 if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD)
254 ret = ssl3_ctrl(s, cmd, larg, parg);
260 void dtls1_start_timer(SSL *s)
262 unsigned int sec, usec;
264 #ifndef OPENSSL_NO_SCTP
265 /* Disable timer for SCTP */
266 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
267 memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
273 * If timer is not set, initialize duration with 1 second or
274 * a user-specified value if the timer callback is installed.
276 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
278 if (s->d1->timer_cb != NULL)
279 s->d1->timeout_duration_us = s->d1->timer_cb(s, 0);
281 s->d1->timeout_duration_us = 1000000;
284 /* Set timeout to current time */
285 get_current_time(&(s->d1->next_timeout));
287 /* Add duration to current time */
289 sec = s->d1->timeout_duration_us / 1000000;
290 usec = s->d1->timeout_duration_us - (sec * 1000000);
292 s->d1->next_timeout.tv_sec += sec;
293 s->d1->next_timeout.tv_usec += usec;
295 if (s->d1->next_timeout.tv_usec >= 1000000) {
296 s->d1->next_timeout.tv_sec++;
297 s->d1->next_timeout.tv_usec -= 1000000;
300 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
301 &(s->d1->next_timeout));
304 struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft)
306 struct timeval timenow;
308 /* If no timeout is set, just return NULL */
309 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
313 /* Get current time */
314 get_current_time(&timenow);
316 /* If timer already expired, set remaining time to 0 */
317 if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
318 (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
319 s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
320 memset(timeleft, 0, sizeof(*timeleft));
324 /* Calculate time left until timer expires */
325 memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
326 timeleft->tv_sec -= timenow.tv_sec;
327 timeleft->tv_usec -= timenow.tv_usec;
328 if (timeleft->tv_usec < 0) {
330 timeleft->tv_usec += 1000000;
334 * If remaining time is less than 15 ms, set it to 0 to prevent issues
335 * because of small divergences with socket timeouts.
337 if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
338 memset(timeleft, 0, sizeof(*timeleft));
344 int dtls1_is_timer_expired(SSL *s)
346 struct timeval timeleft;
348 /* Get time left until timeout, return false if no timer running */
349 if (dtls1_get_timeout(s, &timeleft) == NULL) {
353 /* Return false if timer is not expired yet */
354 if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
358 /* Timer expired, so return true */
362 static void dtls1_double_timeout(SSL *s)
364 s->d1->timeout_duration_us *= 2;
365 if (s->d1->timeout_duration_us > 60000000)
366 s->d1->timeout_duration_us = 60000000;
369 void dtls1_stop_timer(SSL *s)
371 /* Reset everything */
372 s->d1->timeout_num_alerts = 0;
373 memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
374 s->d1->timeout_duration_us = 1000000;
375 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
376 &(s->d1->next_timeout));
377 /* Clear retransmission buffer */
378 dtls1_clear_sent_buffer(s);
381 int dtls1_check_timeout_num(SSL *s)
385 s->d1->timeout_num_alerts++;
387 /* Reduce MTU after 2 unsuccessful retransmissions */
388 if (s->d1->timeout_num_alerts > 2
389 && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
391 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL);
392 if (mtu < s->d1->mtu)
396 if (s->d1->timeout_num_alerts > DTLS1_TMO_ALERT_COUNT) {
397 /* fail the connection, enough alerts have been sent */
398 SSLfatal(s, SSL_AD_NO_ALERT, SSL_R_READ_TIMEOUT_EXPIRED);
405 int dtls1_handle_timeout(SSL *s)
407 /* if no timer is expired, don't do anything */
408 if (!dtls1_is_timer_expired(s)) {
412 if (s->d1->timer_cb != NULL)
413 s->d1->timeout_duration_us = s->d1->timer_cb(s, s->d1->timeout_duration_us);
415 dtls1_double_timeout(s);
417 if (dtls1_check_timeout_num(s) < 0) {
418 /* SSLfatal() already called */
422 dtls1_start_timer(s);
423 /* Calls SSLfatal() if required */
424 return dtls1_retransmit_buffered_messages(s);
427 static void get_current_time(struct timeval *t)
437 SystemTimeToFileTime(&st, &now.ft);
438 /* re-bias to 1/1/1970 */
440 now.ul -= 116444736000000000ULL;
443 now.ul -= 116444736000000000UI64;
446 t->tv_sec = (long)(now.ul / 10000000);
447 t->tv_usec = ((int)(now.ul % 10000000)) / 10;
449 gettimeofday(t, NULL);
453 #define LISTEN_SUCCESS 2
454 #define LISTEN_SEND_VERIFY_REQUEST 1
456 #ifndef OPENSSL_NO_SOCK
457 int DTLSv1_listen(SSL *s, BIO_ADDR *client)
459 int next, n, ret = 0;
460 unsigned char cookie[DTLS1_COOKIE_LENGTH];
461 unsigned char seq[SEQ_NUM_SIZE];
462 const unsigned char *data;
463 unsigned char *buf, *wbuf;
464 size_t fragoff, fraglen, msglen, reclen, align = 0;
465 unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen;
467 BIO_ADDR *tmpclient = NULL;
468 PACKET pkt, msgpkt, msgpayload, session, cookiepkt;
470 if (s->handshake_func == NULL) {
471 /* Not properly initialized yet */
472 SSL_set_accept_state(s);
475 /* Ensure there is no state left over from a previous invocation */
481 rbio = SSL_get_rbio(s);
482 wbio = SSL_get_wbio(s);
484 if (!rbio || !wbio) {
485 ERR_raise(ERR_LIB_SSL, SSL_R_BIO_NOT_SET);
490 * Note: This check deliberately excludes DTLS1_BAD_VER because that version
491 * requires the MAC to be calculated *including* the first ClientHello
492 * (without the cookie). Since DTLSv1_listen is stateless that cannot be
493 * supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via
496 if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
497 ERR_raise(ERR_LIB_SSL, SSL_R_UNSUPPORTED_SSL_VERSION);
501 if (!ssl3_setup_buffers(s)) {
502 /* ERR_raise() already called */
505 buf = RECORD_LAYER_get_rbuf(&s->rlayer)->buf;
506 wbuf = RECORD_LAYER_get_wbuf(&s->rlayer)[0].buf;
507 #if defined(SSL3_ALIGN_PAYLOAD)
508 # if SSL3_ALIGN_PAYLOAD != 0
510 * Using SSL3_RT_HEADER_LENGTH here instead of DTLS1_RT_HEADER_LENGTH for
511 * consistency with ssl3_read_n. In practice it should make no difference
512 * for sensible values of SSL3_ALIGN_PAYLOAD because the difference between
513 * SSL3_RT_HEADER_LENGTH and DTLS1_RT_HEADER_LENGTH is exactly 8
515 align = (size_t)buf + SSL3_RT_HEADER_LENGTH;
516 align = SSL3_ALIGN_PAYLOAD - 1 - ((align - 1) % SSL3_ALIGN_PAYLOAD);
525 n = BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH
526 + DTLS1_RT_HEADER_LENGTH);
528 if (BIO_should_retry(rbio)) {
529 /* Non-blocking IO */
535 if (!PACKET_buf_init(&pkt, buf, n)) {
536 ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
541 * Parse the received record. If there are any problems with it we just
542 * dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is
543 * resilient in the face of invalid records (e.g., invalid formatting,
544 * length, MAC, etc.). In general, invalid records SHOULD be silently
545 * discarded, thus preserving the association; however, an error MAY be
546 * logged for diagnostic purposes."
549 /* this packet contained a partial record, dump it */
550 if (n < DTLS1_RT_HEADER_LENGTH) {
551 ERR_raise(ERR_LIB_SSL, SSL_R_RECORD_TOO_SMALL);
556 s->msg_callback(0, 0, SSL3_RT_HEADER, buf,
557 DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
559 /* Get the record header */
560 if (!PACKET_get_1(&pkt, &rectype)
561 || !PACKET_get_1(&pkt, &versmajor)) {
562 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
566 if (rectype != SSL3_RT_HANDSHAKE) {
567 ERR_raise(ERR_LIB_SSL, SSL_R_UNEXPECTED_MESSAGE);
572 * Check record version number. We only check that the major version is
575 if (versmajor != DTLS1_VERSION_MAJOR) {
576 ERR_raise(ERR_LIB_SSL, SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
580 if (!PACKET_forward(&pkt, 1)
581 /* Save the sequence number: 64 bits, with top 2 bytes = epoch */
582 || !PACKET_copy_bytes(&pkt, seq, SEQ_NUM_SIZE)
583 || !PACKET_get_length_prefixed_2(&pkt, &msgpkt)) {
584 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
587 reclen = PACKET_remaining(&msgpkt);
589 * We allow data remaining at the end of the packet because there could
590 * be a second record (but we ignore it)
593 /* This is an initial ClientHello so the epoch has to be 0 */
594 if (seq[0] != 0 || seq[1] != 0) {
595 ERR_raise(ERR_LIB_SSL, SSL_R_UNEXPECTED_MESSAGE);
599 /* Get a pointer to the raw message for the later callback */
600 data = PACKET_data(&msgpkt);
602 /* Finished processing the record header, now process the message */
603 if (!PACKET_get_1(&msgpkt, &msgtype)
604 || !PACKET_get_net_3_len(&msgpkt, &msglen)
605 || !PACKET_get_net_2(&msgpkt, &msgseq)
606 || !PACKET_get_net_3_len(&msgpkt, &fragoff)
607 || !PACKET_get_net_3_len(&msgpkt, &fraglen)
608 || !PACKET_get_sub_packet(&msgpkt, &msgpayload, fraglen)
609 || PACKET_remaining(&msgpkt) != 0) {
610 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
614 if (msgtype != SSL3_MT_CLIENT_HELLO) {
615 ERR_raise(ERR_LIB_SSL, SSL_R_UNEXPECTED_MESSAGE);
619 /* Message sequence number can only be 0 or 1 */
621 ERR_raise(ERR_LIB_SSL, SSL_R_INVALID_SEQUENCE_NUMBER);
626 * We don't support fragment reassembly for ClientHellos whilst
627 * listening because that would require server side state (which is
628 * against the whole point of the ClientHello/HelloVerifyRequest
629 * mechanism). Instead we only look at the first ClientHello fragment
630 * and require that the cookie must be contained within it.
632 if (fragoff != 0 || fraglen > msglen) {
633 /* Non initial ClientHello fragment (or bad fragment) */
634 ERR_raise(ERR_LIB_SSL, SSL_R_FRAGMENTED_CLIENT_HELLO);
639 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, data,
640 fraglen + DTLS1_HM_HEADER_LENGTH, s,
641 s->msg_callback_arg);
643 if (!PACKET_get_net_2(&msgpayload, &clientvers)) {
644 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
649 * Verify client version is supported
651 if (DTLS_VERSION_LT(clientvers, (unsigned int)s->method->version) &&
652 s->method->version != DTLS_ANY_VERSION) {
653 ERR_raise(ERR_LIB_SSL, SSL_R_WRONG_VERSION_NUMBER);
657 if (!PACKET_forward(&msgpayload, SSL3_RANDOM_SIZE)
658 || !PACKET_get_length_prefixed_1(&msgpayload, &session)
659 || !PACKET_get_length_prefixed_1(&msgpayload, &cookiepkt)) {
661 * Could be malformed or the cookie does not fit within the initial
662 * ClientHello fragment. Either way we can't handle it.
664 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
669 * Check if we have a cookie or not. If not we need to send a
670 * HelloVerifyRequest.
672 if (PACKET_remaining(&cookiepkt) == 0) {
673 next = LISTEN_SEND_VERIFY_REQUEST;
676 * We have a cookie, so lets check it.
678 if (s->ctx->app_verify_cookie_cb == NULL) {
679 ERR_raise(ERR_LIB_SSL, SSL_R_NO_VERIFY_COOKIE_CALLBACK);
683 if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&cookiepkt),
684 (unsigned int)PACKET_remaining(&cookiepkt)) == 0) {
686 * We treat invalid cookies in the same was as no cookie as
689 next = LISTEN_SEND_VERIFY_REQUEST;
691 /* Cookie verification succeeded */
692 next = LISTEN_SUCCESS;
696 if (next == LISTEN_SEND_VERIFY_REQUEST) {
698 unsigned int version;
702 * There was no cookie in the ClientHello so we need to send a
703 * HelloVerifyRequest. If this fails we do not worry about trying
704 * to resend, we just drop it.
707 /* Generate the cookie */
708 if (s->ctx->app_gen_cookie_cb == NULL ||
709 s->ctx->app_gen_cookie_cb(s, cookie, &cookielen) == 0 ||
711 ERR_raise(ERR_LIB_SSL, SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
717 * Special case: for hello verify request, client version 1.0 and we
718 * haven't decided which version to use yet send back using version
719 * 1.0 header: otherwise some clients will ignore it.
721 version = (s->method->version == DTLS_ANY_VERSION) ? DTLS1_VERSION
724 /* Construct the record and message headers */
725 if (!WPACKET_init_static_len(&wpkt,
727 ssl_get_max_send_fragment(s)
728 + DTLS1_RT_HEADER_LENGTH,
730 || !WPACKET_put_bytes_u8(&wpkt, SSL3_RT_HANDSHAKE)
731 || !WPACKET_put_bytes_u16(&wpkt, version)
733 * Record sequence number is always the same as in the
734 * received ClientHello
736 || !WPACKET_memcpy(&wpkt, seq, SEQ_NUM_SIZE)
737 /* End of record, start sub packet for message */
738 || !WPACKET_start_sub_packet_u16(&wpkt)
740 || !WPACKET_put_bytes_u8(&wpkt,
741 DTLS1_MT_HELLO_VERIFY_REQUEST)
743 * Message length - doesn't follow normal TLS convention:
744 * the length isn't the last thing in the message header.
745 * We'll need to fill this in later when we know the
746 * length. Set it to zero for now
748 || !WPACKET_put_bytes_u24(&wpkt, 0)
750 * Message sequence number is always 0 for a
753 || !WPACKET_put_bytes_u16(&wpkt, 0)
755 * We never fragment a HelloVerifyRequest, so fragment
758 || !WPACKET_put_bytes_u24(&wpkt, 0)
760 * Fragment length is the same as message length, but
761 * this *is* the last thing in the message header so we
762 * can just start a sub-packet. No need to come back
763 * later for this one.
765 || !WPACKET_start_sub_packet_u24(&wpkt)
766 /* Create the actual HelloVerifyRequest body */
767 || !dtls_raw_hello_verify_request(&wpkt, cookie, cookielen)
768 /* Close message body */
769 || !WPACKET_close(&wpkt)
770 /* Close record body */
771 || !WPACKET_close(&wpkt)
772 || !WPACKET_get_total_written(&wpkt, &wreclen)
773 || !WPACKET_finish(&wpkt)) {
774 ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
775 WPACKET_cleanup(&wpkt);
781 * Fix up the message len in the message header. Its the same as the
782 * fragment len which has been filled in by WPACKET, so just copy
783 * that. Destination for the message len is after the record header
784 * plus one byte for the message content type. The source is the
785 * last 3 bytes of the message header
787 memcpy(&wbuf[DTLS1_RT_HEADER_LENGTH + 1],
788 &wbuf[DTLS1_RT_HEADER_LENGTH + DTLS1_HM_HEADER_LENGTH - 3],
792 s->msg_callback(1, 0, SSL3_RT_HEADER, buf,
793 DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
795 if ((tmpclient = BIO_ADDR_new()) == NULL) {
796 ERR_raise(ERR_LIB_SSL, ERR_R_MALLOC_FAILURE);
801 * This is unnecessary if rbio and wbio are one and the same - but
802 * maybe they're not. We ignore errors here - some BIOs do not
805 if (BIO_dgram_get_peer(rbio, tmpclient) > 0) {
806 (void)BIO_dgram_set_peer(wbio, tmpclient);
808 BIO_ADDR_free(tmpclient);
811 if (BIO_write(wbio, wbuf, wreclen) < (int)wreclen) {
812 if (BIO_should_retry(wbio)) {
814 * Non-blocking IO...but we're stateless, so we're just
815 * going to drop this packet.
822 if (BIO_flush(wbio) <= 0) {
823 if (BIO_should_retry(wbio)) {
825 * Non-blocking IO...but we're stateless, so we're just
826 * going to drop this packet.
833 } while (next != LISTEN_SUCCESS);
836 * Set expected sequence numbers to continue the handshake.
838 s->d1->handshake_read_seq = 1;
839 s->d1->handshake_write_seq = 1;
840 s->d1->next_handshake_write_seq = 1;
841 DTLS_RECORD_LAYER_set_write_sequence(&s->rlayer, seq);
844 * We are doing cookie exchange, so make sure we set that option in the
847 SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
850 * Tell the state machine that we've done the initial hello verify
853 ossl_statem_set_hello_verify_done(s);
856 * Some BIOs may not support this. If we fail we clear the client address
858 if (BIO_dgram_get_peer(rbio, client) <= 0)
859 BIO_ADDR_clear(client);
861 /* Buffer the record in the processed_rcds queue */
862 if (!dtls_buffer_listen_record(s, reclen, seq, align))
867 BIO_ADDR_free(tmpclient);
872 static int dtls1_handshake_write(SSL *s)
874 return dtls1_do_write(s, SSL3_RT_HANDSHAKE);
877 int dtls1_shutdown(SSL *s)
880 #ifndef OPENSSL_NO_SCTP
883 wbio = SSL_get_wbio(s);
884 if (wbio != NULL && BIO_dgram_is_sctp(wbio) &&
885 !(s->shutdown & SSL_SENT_SHUTDOWN)) {
886 ret = BIO_dgram_sctp_wait_for_dry(wbio);
891 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1,
895 ret = ssl3_shutdown(s);
896 #ifndef OPENSSL_NO_SCTP
897 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
902 int dtls1_query_mtu(SSL *s)
904 if (s->d1->link_mtu) {
906 s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
910 /* AHA! Figure out the MTU, and stick to the right size */
911 if (s->d1->mtu < dtls1_min_mtu(s)) {
912 if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
914 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
917 * I've seen the kernel return bogus numbers when it doesn't know
918 * (initial write), so just make sure we have a reasonable number
920 if (s->d1->mtu < dtls1_min_mtu(s)) {
922 s->d1->mtu = dtls1_min_mtu(s);
923 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
924 (long)s->d1->mtu, NULL);
932 static size_t dtls1_link_min_mtu(void)
934 return (g_probable_mtu[(sizeof(g_probable_mtu) /
935 sizeof(g_probable_mtu[0])) - 1]);
938 size_t dtls1_min_mtu(SSL *s)
940 return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
943 size_t DTLS_get_data_mtu(const SSL *s)
945 size_t mac_overhead, int_overhead, blocksize, ext_overhead;
946 const SSL_CIPHER *ciph = SSL_get_current_cipher(s);
947 size_t mtu = s->d1->mtu;
952 if (!ssl_cipher_get_overhead(ciph, &mac_overhead, &int_overhead,
953 &blocksize, &ext_overhead))
957 ext_overhead += mac_overhead;
959 int_overhead += mac_overhead;
961 /* Subtract external overhead (e.g. IV/nonce, separate MAC) */
962 if (ext_overhead + DTLS1_RT_HEADER_LENGTH >= mtu)
964 mtu -= ext_overhead + DTLS1_RT_HEADER_LENGTH;
966 /* Round encrypted payload down to cipher block size (for CBC etc.)
967 * No check for overflow since 'mtu % blocksize' cannot exceed mtu. */
969 mtu -= (mtu % blocksize);
971 /* Subtract internal overhead (e.g. CBC padding len byte) */
972 if (int_overhead >= mtu)
979 void DTLS_set_timer_cb(SSL *s, DTLS_timer_cb cb)
981 s->d1->timer_cb = cb;