2 * Copyright 2005-2016 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
11 #include <openssl/objects.h>
12 #include <openssl/rand.h>
15 #if defined(OPENSSL_SYS_VXWORKS)
16 # include <sys/times.h>
17 #elif !defined(OPENSSL_SYS_WIN32)
18 # include <sys/time.h>
21 static void get_current_time(struct timeval *t);
22 static int dtls1_handshake_write(SSL *s);
23 static size_t dtls1_link_min_mtu(void);
25 /* XDTLS: figure out the right values */
26 static const size_t g_probable_mtu[] = { 1500, 512, 256 };
28 const SSL3_ENC_METHOD DTLSv1_enc_data = {
32 tls1_generate_master_secret,
33 tls1_change_cipher_state,
34 tls1_final_finish_mac,
35 TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
36 TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
38 tls1_export_keying_material,
39 SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV,
40 dtls1_set_handshake_header,
41 dtls1_close_construct_packet,
45 const SSL3_ENC_METHOD DTLSv1_2_enc_data = {
49 tls1_generate_master_secret,
50 tls1_change_cipher_state,
51 tls1_final_finish_mac,
52 TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
53 TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
55 tls1_export_keying_material,
56 SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV | SSL_ENC_FLAG_SIGALGS
57 | SSL_ENC_FLAG_SHA256_PRF | SSL_ENC_FLAG_TLS1_2_CIPHERS,
58 dtls1_set_handshake_header,
59 dtls1_close_construct_packet,
63 long dtls1_default_timeout(void)
66 * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for
67 * http, the cache would over fill
76 if (!DTLS_RECORD_LAYER_new(&s->rlayer)) {
82 if ((d1 = OPENSSL_zalloc(sizeof(*d1))) == NULL) {
87 d1->buffered_messages = pqueue_new();
88 d1->sent_messages = pqueue_new();
91 d1->cookie_len = sizeof(s->d1->cookie);
97 if (d1->buffered_messages == NULL || d1->sent_messages == NULL) {
98 pqueue_free(d1->buffered_messages);
99 pqueue_free(d1->sent_messages);
107 if (!s->method->ssl_clear(s))
113 static void dtls1_clear_queues(SSL *s)
115 dtls1_clear_received_buffer(s);
116 dtls1_clear_sent_buffer(s);
119 void dtls1_clear_received_buffer(SSL *s)
122 hm_fragment *frag = NULL;
124 while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) {
125 frag = (hm_fragment *)item->data;
126 dtls1_hm_fragment_free(frag);
131 void dtls1_clear_sent_buffer(SSL *s)
134 hm_fragment *frag = NULL;
136 while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) {
137 frag = (hm_fragment *)item->data;
138 dtls1_hm_fragment_free(frag);
144 void dtls1_free(SSL *s)
146 DTLS_RECORD_LAYER_free(&s->rlayer);
150 dtls1_clear_queues(s);
152 pqueue_free(s->d1->buffered_messages);
153 pqueue_free(s->d1->sent_messages);
159 int dtls1_clear(SSL *s)
161 pqueue *buffered_messages;
162 pqueue *sent_messages;
166 DTLS_RECORD_LAYER_clear(&s->rlayer);
169 buffered_messages = s->d1->buffered_messages;
170 sent_messages = s->d1->sent_messages;
172 link_mtu = s->d1->link_mtu;
174 dtls1_clear_queues(s);
176 memset(s->d1, 0, sizeof(*s->d1));
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 #ifndef OPENSSL_NO_SCTP
245 /* Disable timer for SCTP */
246 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
247 memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
252 /* If timer is not set, initialize duration with 1 second */
253 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
254 s->d1->timeout_duration = 1;
257 /* Set timeout to current time */
258 get_current_time(&(s->d1->next_timeout));
260 /* Add duration to current time */
261 s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
262 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
263 &(s->d1->next_timeout));
266 struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft)
268 struct timeval timenow;
270 /* If no timeout is set, just return NULL */
271 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
275 /* Get current time */
276 get_current_time(&timenow);
278 /* If timer already expired, set remaining time to 0 */
279 if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
280 (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
281 s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
282 memset(timeleft, 0, sizeof(*timeleft));
286 /* Calculate time left until timer expires */
287 memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
288 timeleft->tv_sec -= timenow.tv_sec;
289 timeleft->tv_usec -= timenow.tv_usec;
290 if (timeleft->tv_usec < 0) {
292 timeleft->tv_usec += 1000000;
296 * If remaining time is less than 15 ms, set it to 0 to prevent issues
297 * because of small divergences with socket timeouts.
299 if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
300 memset(timeleft, 0, sizeof(*timeleft));
306 int dtls1_is_timer_expired(SSL *s)
308 struct timeval timeleft;
310 /* Get time left until timeout, return false if no timer running */
311 if (dtls1_get_timeout(s, &timeleft) == NULL) {
315 /* Return false if timer is not expired yet */
316 if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
320 /* Timer expired, so return true */
324 void dtls1_double_timeout(SSL *s)
326 s->d1->timeout_duration *= 2;
327 if (s->d1->timeout_duration > 60)
328 s->d1->timeout_duration = 60;
329 dtls1_start_timer(s);
332 void dtls1_stop_timer(SSL *s)
334 /* Reset everything */
335 memset(&s->d1->timeout, 0, sizeof(s->d1->timeout));
336 memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
337 s->d1->timeout_duration = 1;
338 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
339 &(s->d1->next_timeout));
340 /* Clear retransmission buffer */
341 dtls1_clear_sent_buffer(s);
344 int dtls1_check_timeout_num(SSL *s)
348 s->d1->timeout.num_alerts++;
350 /* Reduce MTU after 2 unsuccessful retransmissions */
351 if (s->d1->timeout.num_alerts > 2
352 && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
354 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL);
355 if (mtu < s->d1->mtu)
359 if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) {
360 /* fail the connection, enough alerts have been sent */
361 SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM, SSL_R_READ_TIMEOUT_EXPIRED);
368 int dtls1_handle_timeout(SSL *s)
370 /* if no timer is expired, don't do anything */
371 if (!dtls1_is_timer_expired(s)) {
375 dtls1_double_timeout(s);
377 if (dtls1_check_timeout_num(s) < 0)
380 s->d1->timeout.read_timeouts++;
381 if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) {
382 s->d1->timeout.read_timeouts = 1;
385 dtls1_start_timer(s);
386 return dtls1_retransmit_buffered_messages(s);
389 static void get_current_time(struct timeval *t)
399 SystemTimeToFileTime(&st, &now.ft);
400 /* re-bias to 1/1/1970 */
402 now.ul -= 116444736000000000ULL;
405 now.ul -= 116444736000000000UI64;
408 t->tv_sec = (long)(now.ul / 10000000);
409 t->tv_usec = ((int)(now.ul % 10000000)) / 10;
411 gettimeofday(t, NULL);
415 #define LISTEN_SUCCESS 2
416 #define LISTEN_SEND_VERIFY_REQUEST 1
418 #ifndef OPENSSL_NO_SOCK
419 int DTLSv1_listen(SSL *s, BIO_ADDR *client)
421 int next, n, ret = 0, clearpkt = 0;
422 unsigned char cookie[DTLS1_COOKIE_LENGTH];
423 unsigned char seq[SEQ_NUM_SIZE];
424 const unsigned char *data;
426 size_t fragoff, fraglen, msglen;
427 unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen;
430 BIO_ADDR *tmpclient = NULL;
431 PACKET pkt, msgpkt, msgpayload, session, cookiepkt;
433 if (s->handshake_func == NULL) {
434 /* Not properly initialized yet */
435 SSL_set_accept_state(s);
438 /* Ensure there is no state left over from a previous invocation */
444 rbio = SSL_get_rbio(s);
445 wbio = SSL_get_wbio(s);
447 if (!rbio || !wbio) {
448 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BIO_NOT_SET);
453 * We only peek at incoming ClientHello's until we're sure we are going to
454 * to respond with a HelloVerifyRequest. If its a ClientHello with a valid
455 * cookie then we leave it in the BIO for accept to handle.
457 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);
460 * Note: This check deliberately excludes DTLS1_BAD_VER because that version
461 * requires the MAC to be calculated *including* the first ClientHello
462 * (without the cookie). Since DTLSv1_listen is stateless that cannot be
463 * supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via
466 if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
467 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNSUPPORTED_SSL_VERSION);
471 if (s->init_buf == NULL) {
472 if ((bufm = BUF_MEM_new()) == NULL) {
473 SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
477 if (!BUF_MEM_grow(bufm, SSL3_RT_MAX_PLAIN_LENGTH)) {
479 SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
484 buf = (unsigned char *)s->init_buf->data;
491 * Technically a ClientHello could be SSL3_RT_MAX_PLAIN_LENGTH
492 * + DTLS1_RT_HEADER_LENGTH bytes long. Normally init_buf does not store
493 * the record header as well, but we do here. We've set up init_buf to
494 * be the standard size for simplicity. In practice we shouldn't ever
495 * receive a ClientHello as long as this. If we do it will get dropped
496 * in the record length check below.
498 n = BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
501 if (BIO_should_retry(rbio)) {
502 /* Non-blocking IO */
508 /* If we hit any problems we need to clear this packet from the BIO */
511 if (!PACKET_buf_init(&pkt, buf, n)) {
512 SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_INTERNAL_ERROR);
517 * Parse the received record. If there are any problems with it we just
518 * dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is
519 * resilient in the face of invalid records (e.g., invalid formatting,
520 * length, MAC, etc.). In general, invalid records SHOULD be silently
521 * discarded, thus preserving the association; however, an error MAY be
522 * logged for diagnostic purposes."
525 /* this packet contained a partial record, dump it */
526 if (n < DTLS1_RT_HEADER_LENGTH) {
527 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_RECORD_TOO_SMALL);
532 s->msg_callback(0, 0, SSL3_RT_HEADER, buf,
533 DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
535 /* Get the record header */
536 if (!PACKET_get_1(&pkt, &rectype)
537 || !PACKET_get_1(&pkt, &versmajor)) {
538 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
542 if (rectype != SSL3_RT_HANDSHAKE) {
543 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
548 * Check record version number. We only check that the major version is
551 if (versmajor != DTLS1_VERSION_MAJOR) {
552 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
556 if (!PACKET_forward(&pkt, 1)
557 /* Save the sequence number: 64 bits, with top 2 bytes = epoch */
558 || !PACKET_copy_bytes(&pkt, seq, SEQ_NUM_SIZE)
559 || !PACKET_get_length_prefixed_2(&pkt, &msgpkt)) {
560 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
564 * We allow data remaining at the end of the packet because there could
565 * be a second record (but we ignore it)
568 /* This is an initial ClientHello so the epoch has to be 0 */
569 if (seq[0] != 0 || seq[1] != 0) {
570 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
574 /* Get a pointer to the raw message for the later callback */
575 data = PACKET_data(&msgpkt);
577 /* Finished processing the record header, now process the message */
578 if (!PACKET_get_1(&msgpkt, &msgtype)
579 || !PACKET_get_net_3_len(&msgpkt, &msglen)
580 || !PACKET_get_net_2(&msgpkt, &msgseq)
581 || !PACKET_get_net_3_len(&msgpkt, &fragoff)
582 || !PACKET_get_net_3_len(&msgpkt, &fraglen)
583 || !PACKET_get_sub_packet(&msgpkt, &msgpayload, fraglen)
584 || PACKET_remaining(&msgpkt) != 0) {
585 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
589 if (msgtype != SSL3_MT_CLIENT_HELLO) {
590 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
594 /* Message sequence number can only be 0 or 1 */
596 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_INVALID_SEQUENCE_NUMBER);
601 * We don't support fragment reassembly for ClientHellos whilst
602 * listening because that would require server side state (which is
603 * against the whole point of the ClientHello/HelloVerifyRequest
604 * mechanism). Instead we only look at the first ClientHello fragment
605 * and require that the cookie must be contained within it.
607 if (fragoff != 0 || fraglen > msglen) {
608 /* Non initial ClientHello fragment (or bad fragment) */
609 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_FRAGMENTED_CLIENT_HELLO);
614 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, data,
615 fraglen + DTLS1_HM_HEADER_LENGTH, s,
616 s->msg_callback_arg);
618 if (!PACKET_get_net_2(&msgpayload, &clientvers)) {
619 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
624 * Verify client version is supported
626 if (DTLS_VERSION_LT(clientvers, (unsigned int)s->method->version) &&
627 s->method->version != DTLS_ANY_VERSION) {
628 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_WRONG_VERSION_NUMBER);
632 if (!PACKET_forward(&msgpayload, SSL3_RANDOM_SIZE)
633 || !PACKET_get_length_prefixed_1(&msgpayload, &session)
634 || !PACKET_get_length_prefixed_1(&msgpayload, &cookiepkt)) {
636 * Could be malformed or the cookie does not fit within the initial
637 * ClientHello fragment. Either way we can't handle it.
639 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
644 * Check if we have a cookie or not. If not we need to send a
645 * HelloVerifyRequest.
647 if (PACKET_remaining(&cookiepkt) == 0) {
648 next = LISTEN_SEND_VERIFY_REQUEST;
651 * We have a cookie, so lets check it.
653 if (s->ctx->app_verify_cookie_cb == NULL) {
654 SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_NO_VERIFY_COOKIE_CALLBACK);
658 if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&cookiepkt),
659 (unsigned int)PACKET_remaining(&cookiepkt)) == 0) {
661 * We treat invalid cookies in the same was as no cookie as
664 next = LISTEN_SEND_VERIFY_REQUEST;
666 /* Cookie verification succeeded */
667 next = LISTEN_SUCCESS;
671 if (next == LISTEN_SEND_VERIFY_REQUEST) {
673 unsigned int version;
677 * There was no cookie in the ClientHello so we need to send a
678 * HelloVerifyRequest. If this fails we do not worry about trying
679 * to resend, we just drop it.
683 * Dump the read packet, we don't need it any more. Ignore return
686 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL);
687 BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
688 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);
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 SSLerr(SSL_F_DTLSV1_LISTEN, 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(&wpkt, s->init_buf)
709 || !WPACKET_put_bytes_u8(&wpkt, SSL3_RT_HANDSHAKE)
710 || !WPACKET_put_bytes_u16(&wpkt, version)
712 * Record sequence number is always the same as in the
713 * received ClientHello
715 || !WPACKET_memcpy(&wpkt, seq, SEQ_NUM_SIZE)
716 /* End of record, start sub packet for message */
717 || !WPACKET_start_sub_packet_u16(&wpkt)
719 || !WPACKET_put_bytes_u8(&wpkt,
720 DTLS1_MT_HELLO_VERIFY_REQUEST)
722 * Message length - doesn't follow normal TLS convention:
723 * the length isn't the last thing in the message header.
724 * We'll need to fill this in later when we know the
725 * length. Set it to zero for now
727 || !WPACKET_put_bytes_u24(&wpkt, 0)
729 * Message sequence number is always 0 for a
732 || !WPACKET_put_bytes_u16(&wpkt, 0)
734 * We never fragment a HelloVerifyRequest, so fragment
737 || !WPACKET_put_bytes_u24(&wpkt, 0)
739 * Fragment length is the same as message length, but
740 * this *is* the last thing in the message header so we
741 * can just start a sub-packet. No need to come back
742 * later for this one.
744 || !WPACKET_start_sub_packet_u24(&wpkt)
745 /* Create the actual HelloVerifyRequest body */
746 || !dtls_raw_hello_verify_request(&wpkt, cookie, cookielen)
747 /* Close message body */
748 || !WPACKET_close(&wpkt)
749 /* Close record body */
750 || !WPACKET_close(&wpkt)
751 || !WPACKET_get_total_written(&wpkt, &wreclen)
752 || !WPACKET_finish(&wpkt)) {
753 SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_INTERNAL_ERROR);
754 WPACKET_cleanup(&wpkt);
760 * Fix up the message len in the message header. Its the same as the
761 * fragment len which has been filled in by WPACKET, so just copy
762 * that. Destination for the message len is after the record header
763 * plus one byte for the message content type. The source is the
764 * last 3 bytes of the message header
766 memcpy(&buf[DTLS1_RT_HEADER_LENGTH + 1],
767 &buf[DTLS1_RT_HEADER_LENGTH + DTLS1_HM_HEADER_LENGTH - 3],
771 s->msg_callback(1, 0, SSL3_RT_HEADER, buf,
772 DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
774 if ((tmpclient = BIO_ADDR_new()) == NULL) {
775 SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
780 * This is unnecessary if rbio and wbio are one and the same - but
781 * maybe they're not. We ignore errors here - some BIOs do not
784 if (BIO_dgram_get_peer(rbio, tmpclient) > 0) {
785 (void)BIO_dgram_set_peer(wbio, tmpclient);
787 BIO_ADDR_free(tmpclient);
790 /* TODO(size_t): convert this call */
791 if (BIO_write(wbio, buf, wreclen) < (int)wreclen) {
792 if (BIO_should_retry(wbio)) {
794 * Non-blocking IO...but we're stateless, so we're just
795 * going to drop this packet.
802 if (BIO_flush(wbio) <= 0) {
803 if (BIO_should_retry(wbio)) {
805 * Non-blocking IO...but we're stateless, so we're just
806 * going to drop this packet.
813 } while (next != LISTEN_SUCCESS);
816 * Set expected sequence numbers to continue the handshake.
818 s->d1->handshake_read_seq = 1;
819 s->d1->handshake_write_seq = 1;
820 s->d1->next_handshake_write_seq = 1;
821 DTLS_RECORD_LAYER_set_write_sequence(&s->rlayer, seq);
824 * We are doing cookie exchange, so make sure we set that option in the
827 SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
830 * Tell the state machine that we've done the initial hello verify
833 ossl_statem_set_hello_verify_done(s);
836 * Some BIOs may not support this. If we fail we clear the client address
838 if (BIO_dgram_get_peer(rbio, client) <= 0)
839 BIO_ADDR_clear(client);
844 BIO_ADDR_free(tmpclient);
845 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL);
847 /* Dump this packet. Ignore return value */
848 BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
854 static int dtls1_handshake_write(SSL *s)
856 return dtls1_do_write(s, SSL3_RT_HANDSHAKE);
859 int dtls1_shutdown(SSL *s)
862 #ifndef OPENSSL_NO_SCTP
865 wbio = SSL_get_wbio(s);
866 if (wbio != NULL && BIO_dgram_is_sctp(wbio) &&
867 !(s->shutdown & SSL_SENT_SHUTDOWN)) {
868 ret = BIO_dgram_sctp_wait_for_dry(wbio);
873 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1,
877 ret = ssl3_shutdown(s);
878 #ifndef OPENSSL_NO_SCTP
879 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
884 int dtls1_query_mtu(SSL *s)
886 if (s->d1->link_mtu) {
888 s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
892 /* AHA! Figure out the MTU, and stick to the right size */
893 if (s->d1->mtu < dtls1_min_mtu(s)) {
894 if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
896 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
899 * I've seen the kernel return bogus numbers when it doesn't know
900 * (initial write), so just make sure we have a reasonable number
902 if (s->d1->mtu < dtls1_min_mtu(s)) {
904 s->d1->mtu = dtls1_min_mtu(s);
905 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
906 (long)s->d1->mtu, NULL);
914 static size_t dtls1_link_min_mtu(void)
916 return (g_probable_mtu[(sizeof(g_probable_mtu) /
917 sizeof(g_probable_mtu[0])) - 1]);
920 size_t dtls1_min_mtu(SSL *s)
922 return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
925 size_t DTLS_get_data_mtu(const SSL *s)
927 size_t mac_overhead, int_overhead, blocksize, ext_overhead;
928 const SSL_CIPHER *ciph = SSL_get_current_cipher(s);
929 size_t mtu = s->d1->mtu;
934 if (!ssl_cipher_get_overhead(ciph, &mac_overhead, &int_overhead,
935 &blocksize, &ext_overhead))
939 ext_overhead += mac_overhead;
941 int_overhead += mac_overhead;
943 /* Subtract external overhead (e.g. IV/nonce, separate MAC) */
944 if (ext_overhead + DTLS1_RT_HEADER_LENGTH >= mtu)
946 mtu -= ext_overhead + DTLS1_RT_HEADER_LENGTH;
948 /* Round encrypted payload down to cipher block size (for CBC etc.)
949 * No check for overflow since 'mtu % blocksize' cannot exceed mtu. */
951 mtu -= (mtu % blocksize);
953 /* Subtract internal overhead (e.g. CBC padding len byte) */
954 if (int_overhead >= mtu)