2 * Copyright 2005-2023 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"
15 #include "internal/time.h"
17 static int dtls1_handshake_write(SSL_CONNECTION *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 = {
25 tls1_generate_master_secret,
26 tls1_change_cipher_state,
27 tls1_final_finish_mac,
28 TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
29 TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
31 tls1_export_keying_material,
32 SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV,
33 dtls1_set_handshake_header,
34 dtls1_close_construct_packet,
38 const SSL3_ENC_METHOD DTLSv1_2_enc_data = {
40 tls1_generate_master_secret,
41 tls1_change_cipher_state,
42 tls1_final_finish_mac,
43 TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
44 TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
46 tls1_export_keying_material,
47 SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV | SSL_ENC_FLAG_SIGALGS
48 | SSL_ENC_FLAG_SHA256_PRF | SSL_ENC_FLAG_TLS1_2_CIPHERS,
49 dtls1_set_handshake_header,
50 dtls1_close_construct_packet,
54 OSSL_TIME dtls1_default_timeout(void)
57 * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for
58 * http, the cache would over fill
60 return ossl_seconds2time(60 * 60 * 2);
63 int dtls1_new(SSL *ssl)
66 SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl);
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 (!ssl->method->ssl_clear(ssl))
108 static void dtls1_clear_queues(SSL_CONNECTION *s)
110 dtls1_clear_received_buffer(s);
111 dtls1_clear_sent_buffer(s);
114 void dtls1_clear_received_buffer(SSL_CONNECTION *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_CONNECTION *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 *ssl)
141 SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl);
146 DTLS_RECORD_LAYER_free(&s->rlayer);
151 dtls1_clear_queues(s);
152 pqueue_free(s->d1->buffered_messages);
153 pqueue_free(s->d1->sent_messages);
160 int dtls1_clear(SSL *ssl)
162 pqueue *buffered_messages;
163 pqueue *sent_messages;
167 SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl);
172 DTLS_RECORD_LAYER_clear(&s->rlayer);
175 DTLS_timer_cb timer_cb = s->d1->timer_cb;
177 buffered_messages = s->d1->buffered_messages;
178 sent_messages = s->d1->sent_messages;
180 link_mtu = s->d1->link_mtu;
182 dtls1_clear_queues(s);
184 memset(s->d1, 0, sizeof(*s->d1));
186 /* Restore the timer callback from previous state */
187 s->d1->timer_cb = timer_cb;
190 s->d1->cookie_len = sizeof(s->d1->cookie);
193 if (SSL_get_options(ssl) & SSL_OP_NO_QUERY_MTU) {
195 s->d1->link_mtu = link_mtu;
198 s->d1->buffered_messages = buffered_messages;
199 s->d1->sent_messages = sent_messages;
202 if (!ssl3_clear(ssl))
205 if (ssl->method->version == DTLS_ANY_VERSION)
206 s->version = DTLS_MAX_VERSION_INTERNAL;
207 #ifndef OPENSSL_NO_DTLS1_METHOD
208 else if (s->options & SSL_OP_CISCO_ANYCONNECT)
209 s->client_version = s->version = DTLS1_BAD_VER;
212 s->version = ssl->method->version;
217 long dtls1_ctrl(SSL *ssl, int cmd, long larg, void *parg)
221 SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl);
227 case DTLS_CTRL_GET_TIMEOUT:
228 if (dtls1_get_timeout(s, &t)) {
229 *(struct timeval *)parg = ossl_time_to_timeval(t);
233 case DTLS_CTRL_HANDLE_TIMEOUT:
234 ret = dtls1_handle_timeout(s);
236 case DTLS_CTRL_SET_LINK_MTU:
237 if (larg < (long)dtls1_link_min_mtu())
239 s->d1->link_mtu = larg;
241 case DTLS_CTRL_GET_LINK_MIN_MTU:
242 return (long)dtls1_link_min_mtu();
243 case SSL_CTRL_SET_MTU:
245 * We may not have a BIO set yet so can't call dtls1_min_mtu()
246 * We'll have to make do with dtls1_link_min_mtu() and max overhead
248 if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD)
253 ret = ssl3_ctrl(ssl, cmd, larg, parg);
259 static void dtls1_bio_set_next_timeout(BIO * bio, const DTLS1_STATE *d1)
261 struct timeval tv = ossl_time_to_timeval(d1->next_timeout);
263 BIO_ctrl(bio, BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &tv);
266 void dtls1_start_timer(SSL_CONNECTION *s)
269 SSL *ssl = SSL_CONNECTION_GET_SSL(s);
271 #ifndef OPENSSL_NO_SCTP
272 /* Disable timer for SCTP */
273 if (BIO_dgram_is_sctp(SSL_get_wbio(ssl))) {
274 s->d1->next_timeout = ossl_time_zero();
280 * If timer is not set, initialize duration with 1 second or
281 * a user-specified value if the timer callback is installed.
283 if (ossl_time_is_zero(s->d1->next_timeout)) {
284 if (s->d1->timer_cb != NULL)
285 s->d1->timeout_duration_us = s->d1->timer_cb(ssl, 0);
287 s->d1->timeout_duration_us = 1000000;
290 /* Set timeout to current time plus duration */
291 duration = ossl_us2time(s->d1->timeout_duration_us);
292 s->d1->next_timeout = ossl_time_add(ossl_time_now(), duration);
294 /* set s->d1->next_timeout into ssl->rbio interface */
295 dtls1_bio_set_next_timeout(SSL_get_rbio(ssl), s->d1);
298 int dtls1_get_timeout(const SSL_CONNECTION *s, OSSL_TIME *timeleft)
302 /* If no timeout is set, just return NULL */
303 if (ossl_time_is_zero(s->d1->next_timeout))
306 /* Get current time */
307 timenow = ossl_time_now();
310 * If timer already expired or if remaining time is less than 15 ms,
311 * set it to 0 to prevent issues because of small divergences with
314 *timeleft = ossl_time_subtract(s->d1->next_timeout, timenow);
315 if (ossl_time_compare(*timeleft, ossl_ms2time(15)) <= 0)
316 *timeleft = ossl_time_zero();
320 int dtls1_is_timer_expired(SSL_CONNECTION *s)
324 /* Get time left until timeout, return false if no timer running */
325 if (!dtls1_get_timeout(s, &timeleft))
328 /* Return false if timer is not expired yet */
329 if (!ossl_time_is_zero(timeleft))
332 /* Timer expired, so return true */
336 static void dtls1_double_timeout(SSL_CONNECTION *s)
338 s->d1->timeout_duration_us *= 2;
339 if (s->d1->timeout_duration_us > 60000000)
340 s->d1->timeout_duration_us = 60000000;
343 void dtls1_stop_timer(SSL_CONNECTION *s)
345 /* Reset everything */
346 s->d1->timeout_num_alerts = 0;
347 s->d1->next_timeout = ossl_time_zero();
348 s->d1->timeout_duration_us = 1000000;
349 dtls1_bio_set_next_timeout(s->rbio, s->d1);
350 /* Clear retransmission buffer */
351 dtls1_clear_sent_buffer(s);
354 int dtls1_check_timeout_num(SSL_CONNECTION *s)
357 SSL *ssl = SSL_CONNECTION_GET_SSL(s);
359 s->d1->timeout_num_alerts++;
361 /* Reduce MTU after 2 unsuccessful retransmissions */
362 if (s->d1->timeout_num_alerts > 2
363 && !(SSL_get_options(ssl) & SSL_OP_NO_QUERY_MTU)) {
365 BIO_ctrl(SSL_get_wbio(ssl), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL);
366 if (mtu < s->d1->mtu)
370 if (s->d1->timeout_num_alerts > DTLS1_TMO_ALERT_COUNT) {
371 /* fail the connection, enough alerts have been sent */
372 SSLfatal(s, SSL_AD_NO_ALERT, SSL_R_READ_TIMEOUT_EXPIRED);
379 int dtls1_handle_timeout(SSL_CONNECTION *s)
381 /* if no timer is expired, don't do anything */
382 if (!dtls1_is_timer_expired(s)) {
386 if (s->d1->timer_cb != NULL)
387 s->d1->timeout_duration_us = s->d1->timer_cb(SSL_CONNECTION_GET_SSL(s),
388 s->d1->timeout_duration_us);
390 dtls1_double_timeout(s);
392 if (dtls1_check_timeout_num(s) < 0) {
393 /* SSLfatal() already called */
397 dtls1_start_timer(s);
398 /* Calls SSLfatal() if required */
399 return dtls1_retransmit_buffered_messages(s);
402 #define LISTEN_SUCCESS 2
403 #define LISTEN_SEND_VERIFY_REQUEST 1
405 #ifndef OPENSSL_NO_SOCK
406 int DTLSv1_listen(SSL *ssl, BIO_ADDR *client)
408 int next, n, ret = 0;
409 unsigned char cookie[DTLS1_COOKIE_LENGTH];
410 unsigned char seq[SEQ_NUM_SIZE];
411 const unsigned char *data;
412 unsigned char *buf = NULL, *wbuf;
413 size_t fragoff, fraglen, msglen;
414 unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen;
416 BIO_ADDR *tmpclient = NULL;
417 PACKET pkt, msgpkt, msgpayload, session, cookiepkt;
418 SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl);
423 if (s->handshake_func == NULL) {
424 /* Not properly initialized yet */
425 SSL_set_accept_state(ssl);
428 /* Ensure there is no state left over from a previous invocation */
434 rbio = SSL_get_rbio(ssl);
435 wbio = SSL_get_wbio(ssl);
437 if (!rbio || !wbio) {
438 ERR_raise(ERR_LIB_SSL, SSL_R_BIO_NOT_SET);
443 * Note: This check deliberately excludes DTLS1_BAD_VER because that version
444 * requires the MAC to be calculated *including* the first ClientHello
445 * (without the cookie). Since DTLSv1_listen is stateless that cannot be
446 * supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via
449 if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
450 ERR_raise(ERR_LIB_SSL, SSL_R_UNSUPPORTED_SSL_VERSION);
454 buf = OPENSSL_malloc(DTLS1_RT_HEADER_LENGTH + SSL3_RT_MAX_PLAIN_LENGTH);
457 wbuf = OPENSSL_malloc(DTLS1_RT_HEADER_LENGTH + SSL3_RT_MAX_PLAIN_LENGTH);
467 n = BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH
468 + DTLS1_RT_HEADER_LENGTH);
470 if (BIO_should_retry(rbio)) {
471 /* Non-blocking IO */
478 if (!PACKET_buf_init(&pkt, buf, n)) {
479 ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
485 * Parse the received record. If there are any problems with it we just
486 * dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is
487 * resilient in the face of invalid records (e.g., invalid formatting,
488 * length, MAC, etc.). In general, invalid records SHOULD be silently
489 * discarded, thus preserving the association; however, an error MAY be
490 * logged for diagnostic purposes."
493 /* this packet contained a partial record, dump it */
494 if (n < DTLS1_RT_HEADER_LENGTH) {
495 ERR_raise(ERR_LIB_SSL, SSL_R_RECORD_TOO_SMALL);
500 s->msg_callback(0, 0, SSL3_RT_HEADER, buf,
501 DTLS1_RT_HEADER_LENGTH, ssl, s->msg_callback_arg);
503 /* Get the record header */
504 if (!PACKET_get_1(&pkt, &rectype)
505 || !PACKET_get_1(&pkt, &versmajor)) {
506 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
510 if (rectype != SSL3_RT_HANDSHAKE) {
511 ERR_raise(ERR_LIB_SSL, SSL_R_UNEXPECTED_MESSAGE);
516 * Check record version number. We only check that the major version is
519 if (versmajor != DTLS1_VERSION_MAJOR) {
520 ERR_raise(ERR_LIB_SSL, SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
524 if (!PACKET_forward(&pkt, 1)
525 /* Save the sequence number: 64 bits, with top 2 bytes = epoch */
526 || !PACKET_copy_bytes(&pkt, seq, SEQ_NUM_SIZE)
527 || !PACKET_get_length_prefixed_2(&pkt, &msgpkt)) {
528 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
532 * We allow data remaining at the end of the packet because there could
533 * be a second record (but we ignore it)
536 /* This is an initial ClientHello so the epoch has to be 0 */
537 if (seq[0] != 0 || seq[1] != 0) {
538 ERR_raise(ERR_LIB_SSL, SSL_R_UNEXPECTED_MESSAGE);
542 /* Get a pointer to the raw message for the later callback */
543 data = PACKET_data(&msgpkt);
545 /* Finished processing the record header, now process the message */
546 if (!PACKET_get_1(&msgpkt, &msgtype)
547 || !PACKET_get_net_3_len(&msgpkt, &msglen)
548 || !PACKET_get_net_2(&msgpkt, &msgseq)
549 || !PACKET_get_net_3_len(&msgpkt, &fragoff)
550 || !PACKET_get_net_3_len(&msgpkt, &fraglen)
551 || !PACKET_get_sub_packet(&msgpkt, &msgpayload, fraglen)
552 || PACKET_remaining(&msgpkt) != 0) {
553 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
557 if (msgtype != SSL3_MT_CLIENT_HELLO) {
558 ERR_raise(ERR_LIB_SSL, SSL_R_UNEXPECTED_MESSAGE);
562 /* Message sequence number can only be 0 or 1 */
564 ERR_raise(ERR_LIB_SSL, SSL_R_INVALID_SEQUENCE_NUMBER);
569 * We don't support fragment reassembly for ClientHellos whilst
570 * listening because that would require server side state (which is
571 * against the whole point of the ClientHello/HelloVerifyRequest
572 * mechanism). Instead we only look at the first ClientHello fragment
573 * and require that the cookie must be contained within it.
575 if (fragoff != 0 || fraglen > msglen) {
576 /* Non initial ClientHello fragment (or bad fragment) */
577 ERR_raise(ERR_LIB_SSL, SSL_R_FRAGMENTED_CLIENT_HELLO);
582 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, data,
583 fraglen + DTLS1_HM_HEADER_LENGTH, ssl,
584 s->msg_callback_arg);
586 if (!PACKET_get_net_2(&msgpayload, &clientvers)) {
587 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
592 * Verify client version is supported
594 if (DTLS_VERSION_LT(clientvers, (unsigned int)ssl->method->version) &&
595 ssl->method->version != DTLS_ANY_VERSION) {
596 ERR_raise(ERR_LIB_SSL, SSL_R_WRONG_VERSION_NUMBER);
600 if (!PACKET_forward(&msgpayload, SSL3_RANDOM_SIZE)
601 || !PACKET_get_length_prefixed_1(&msgpayload, &session)
602 || !PACKET_get_length_prefixed_1(&msgpayload, &cookiepkt)) {
604 * Could be malformed or the cookie does not fit within the initial
605 * ClientHello fragment. Either way we can't handle it.
607 ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH);
612 * Check if we have a cookie or not. If not we need to send a
613 * HelloVerifyRequest.
615 if (PACKET_remaining(&cookiepkt) == 0) {
616 next = LISTEN_SEND_VERIFY_REQUEST;
619 * We have a cookie, so lets check it.
621 if (ssl->ctx->app_verify_cookie_cb == NULL) {
622 ERR_raise(ERR_LIB_SSL, SSL_R_NO_VERIFY_COOKIE_CALLBACK);
627 if (ssl->ctx->app_verify_cookie_cb(ssl, PACKET_data(&cookiepkt),
628 (unsigned int)PACKET_remaining(&cookiepkt)) == 0) {
630 * We treat invalid cookies in the same was as no cookie as
633 next = LISTEN_SEND_VERIFY_REQUEST;
635 /* Cookie verification succeeded */
636 next = LISTEN_SUCCESS;
640 if (next == LISTEN_SEND_VERIFY_REQUEST) {
642 unsigned int version;
646 * There was no cookie in the ClientHello so we need to send a
647 * HelloVerifyRequest. If this fails we do not worry about trying
648 * to resend, we just drop it.
651 /* Generate the cookie */
652 if (ssl->ctx->app_gen_cookie_cb == NULL ||
653 ssl->ctx->app_gen_cookie_cb(ssl, cookie, &cookielen) == 0 ||
655 ERR_raise(ERR_LIB_SSL, SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
662 * Special case: for hello verify request, client version 1.0 and we
663 * haven't decided which version to use yet send back using version
664 * 1.0 header: otherwise some clients will ignore it.
666 version = (ssl->method->version == DTLS_ANY_VERSION) ? DTLS1_VERSION
669 /* Construct the record and message headers */
670 if (!WPACKET_init_static_len(&wpkt,
672 ssl_get_max_send_fragment(s)
673 + DTLS1_RT_HEADER_LENGTH,
675 || !WPACKET_put_bytes_u8(&wpkt, SSL3_RT_HANDSHAKE)
676 || !WPACKET_put_bytes_u16(&wpkt, version)
678 * Record sequence number is always the same as in the
679 * received ClientHello
681 || !WPACKET_memcpy(&wpkt, seq, SEQ_NUM_SIZE)
682 /* End of record, start sub packet for message */
683 || !WPACKET_start_sub_packet_u16(&wpkt)
685 || !WPACKET_put_bytes_u8(&wpkt,
686 DTLS1_MT_HELLO_VERIFY_REQUEST)
688 * Message length - doesn't follow normal TLS convention:
689 * the length isn't the last thing in the message header.
690 * We'll need to fill this in later when we know the
691 * length. Set it to zero for now
693 || !WPACKET_put_bytes_u24(&wpkt, 0)
695 * Message sequence number is always 0 for a
698 || !WPACKET_put_bytes_u16(&wpkt, 0)
700 * We never fragment a HelloVerifyRequest, so fragment
703 || !WPACKET_put_bytes_u24(&wpkt, 0)
705 * Fragment length is the same as message length, but
706 * this *is* the last thing in the message header so we
707 * can just start a sub-packet. No need to come back
708 * later for this one.
710 || !WPACKET_start_sub_packet_u24(&wpkt)
711 /* Create the actual HelloVerifyRequest body */
712 || !dtls_raw_hello_verify_request(&wpkt, cookie, cookielen)
713 /* Close message body */
714 || !WPACKET_close(&wpkt)
715 /* Close record body */
716 || !WPACKET_close(&wpkt)
717 || !WPACKET_get_total_written(&wpkt, &wreclen)
718 || !WPACKET_finish(&wpkt)) {
719 ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
720 WPACKET_cleanup(&wpkt);
727 * Fix up the message len in the message header. Its the same as the
728 * fragment len which has been filled in by WPACKET, so just copy
729 * that. Destination for the message len is after the record header
730 * plus one byte for the message content type. The source is the
731 * last 3 bytes of the message header
733 memcpy(&wbuf[DTLS1_RT_HEADER_LENGTH + 1],
734 &wbuf[DTLS1_RT_HEADER_LENGTH + DTLS1_HM_HEADER_LENGTH - 3],
738 s->msg_callback(1, 0, SSL3_RT_HEADER, buf,
739 DTLS1_RT_HEADER_LENGTH, ssl,
740 s->msg_callback_arg);
742 if ((tmpclient = BIO_ADDR_new()) == NULL) {
743 ERR_raise(ERR_LIB_SSL, ERR_R_BIO_LIB);
748 * This is unnecessary if rbio and wbio are one and the same - but
749 * maybe they're not. We ignore errors here - some BIOs do not
752 if (BIO_dgram_get_peer(rbio, tmpclient) > 0) {
753 (void)BIO_dgram_set_peer(wbio, tmpclient);
755 BIO_ADDR_free(tmpclient);
758 if (BIO_write(wbio, wbuf, wreclen) < (int)wreclen) {
759 if (BIO_should_retry(wbio)) {
761 * Non-blocking IO...but we're stateless, so we're just
762 * going to drop this packet.
770 if (BIO_flush(wbio) <= 0) {
771 if (BIO_should_retry(wbio)) {
773 * Non-blocking IO...but we're stateless, so we're just
774 * going to drop this packet.
782 } while (next != LISTEN_SUCCESS);
785 * Set expected sequence numbers to continue the handshake.
787 s->d1->handshake_read_seq = 1;
788 s->d1->handshake_write_seq = 1;
789 s->d1->next_handshake_write_seq = 1;
790 s->rlayer.wrlmethod->increment_sequence_ctr(s->rlayer.wrl);
793 * We are doing cookie exchange, so make sure we set that option in the
796 SSL_set_options(ssl, SSL_OP_COOKIE_EXCHANGE);
799 * Tell the state machine that we've done the initial hello verify
802 ossl_statem_set_hello_verify_done(s);
805 * Some BIOs may not support this. If we fail we clear the client address
807 if (BIO_dgram_get_peer(rbio, client) <= 0)
808 BIO_ADDR_clear(client);
810 /* Buffer the record for use by the record layer */
811 if (BIO_write(s->rlayer.rrlnext, buf, n) != n) {
812 ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
818 * Reset the record layer - but this time we can use the record we just
819 * buffered in s->rlayer.rrlnext
821 if (!ssl_set_new_record_layer(s,
823 OSSL_RECORD_DIRECTION_READ,
824 OSSL_RECORD_PROTECTION_LEVEL_NONE, NULL, 0,
825 NULL, 0, NULL, 0, NULL, 0, NULL, 0,
826 NID_undef, NULL, NULL, NULL)) {
827 /* SSLfatal already called */
834 BIO_ADDR_free(tmpclient);
841 static int dtls1_handshake_write(SSL_CONNECTION *s)
843 return dtls1_do_write(s, SSL3_RT_HANDSHAKE);
846 int dtls1_shutdown(SSL *s)
849 #ifndef OPENSSL_NO_SCTP
851 SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL_ONLY(s);
856 wbio = SSL_get_wbio(s);
857 if (wbio != NULL && BIO_dgram_is_sctp(wbio) &&
858 !(sc->shutdown & SSL_SENT_SHUTDOWN)) {
859 ret = BIO_dgram_sctp_wait_for_dry(wbio);
864 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1,
868 ret = ssl3_shutdown(s);
869 #ifndef OPENSSL_NO_SCTP
870 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
875 int dtls1_query_mtu(SSL_CONNECTION *s)
877 SSL *ssl = SSL_CONNECTION_GET_SSL(s);
879 if (s->d1->link_mtu) {
881 s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(ssl));
885 /* AHA! Figure out the MTU, and stick to the right size */
886 if (s->d1->mtu < dtls1_min_mtu(s)) {
887 if (!(SSL_get_options(ssl) & SSL_OP_NO_QUERY_MTU)) {
889 BIO_ctrl(SSL_get_wbio(ssl), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
892 * I've seen the kernel return bogus numbers when it doesn't know
893 * (initial write), so just make sure we have a reasonable number
895 if (s->d1->mtu < dtls1_min_mtu(s)) {
897 s->d1->mtu = dtls1_min_mtu(s);
898 BIO_ctrl(SSL_get_wbio(ssl), BIO_CTRL_DGRAM_SET_MTU,
899 (long)s->d1->mtu, NULL);
907 static size_t dtls1_link_min_mtu(void)
909 return (g_probable_mtu[(sizeof(g_probable_mtu) /
910 sizeof(g_probable_mtu[0])) - 1]);
913 size_t dtls1_min_mtu(SSL_CONNECTION *s)
915 SSL *ssl = SSL_CONNECTION_GET_SSL(s);
917 return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(ssl));
920 size_t DTLS_get_data_mtu(const SSL *ssl)
922 size_t mac_overhead, int_overhead, blocksize, ext_overhead;
923 const SSL_CIPHER *ciph = SSL_get_current_cipher(ssl);
925 const SSL_CONNECTION *s = SSL_CONNECTION_FROM_CONST_SSL_ONLY(ssl);
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 *ssl, DTLS_timer_cb cb)
964 SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl);
969 s->d1->timer_cb = cb;