3 * DTLS implementation written by Nagendra Modadugu
4 * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
6 /* ====================================================================
7 * Copyright (c) 1999-2005 The OpenSSL Project. All rights reserved.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in
18 * the documentation and/or other materials provided with the
21 * 3. All advertising materials mentioning features or use of this
22 * software must display the following acknowledgment:
23 * "This product includes software developed by the OpenSSL Project
24 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
26 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
27 * endorse or promote products derived from this software without
28 * prior written permission. For written permission, please contact
29 * openssl-core@OpenSSL.org.
31 * 5. Products derived from this software may not be called "OpenSSL"
32 * nor may "OpenSSL" appear in their names without prior written
33 * permission of the OpenSSL Project.
35 * 6. Redistributions of any form whatsoever must retain the following
37 * "This product includes software developed by the OpenSSL Project
38 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
40 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
41 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
43 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
44 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
46 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
47 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
49 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
50 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
51 * OF THE POSSIBILITY OF SUCH DAMAGE.
52 * ====================================================================
54 * This product includes cryptographic software written by Eric Young
55 * (eay@cryptsoft.com). This product includes software written by Tim
56 * Hudson (tjh@cryptsoft.com).
62 #include <openssl/objects.h>
63 #include <openssl/rand.h>
66 #if defined(OPENSSL_SYS_VMS)
67 # include <sys/timeb.h>
68 #elif defined(OPENSSL_SYS_NETWARE) && !defined(_WINSOCK2API_)
69 # include <sys/timeval.h>
70 #elif defined(OPENSSL_SYS_VXWORKS)
71 # include <sys/times.h>
72 #elif !defined(OPENSSL_SYS_WIN32)
73 # include <sys/time.h>
76 static void get_current_time(struct timeval *t);
77 static int dtls1_set_handshake_header(SSL *s, int type, unsigned long len);
78 static int dtls1_handshake_write(SSL *s);
79 int dtls1_listen(SSL *s, struct sockaddr *client);
80 static unsigned int dtls1_link_min_mtu(void);
82 /* XDTLS: figure out the right values */
83 static const unsigned int g_probable_mtu[] = { 1500, 512, 256 };
85 const SSL3_ENC_METHOD DTLSv1_enc_data = {
89 tls1_generate_master_secret,
90 tls1_change_cipher_state,
91 tls1_final_finish_mac,
92 TLS1_FINISH_MAC_LENGTH,
94 TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
95 TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
97 tls1_export_keying_material,
98 SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV,
99 DTLS1_HM_HEADER_LENGTH,
100 dtls1_set_handshake_header,
101 dtls1_handshake_write
104 const SSL3_ENC_METHOD DTLSv1_2_enc_data = {
107 tls1_setup_key_block,
108 tls1_generate_master_secret,
109 tls1_change_cipher_state,
110 tls1_final_finish_mac,
111 TLS1_FINISH_MAC_LENGTH,
112 tls1_cert_verify_mac,
113 TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
114 TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
116 tls1_export_keying_material,
117 SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV | SSL_ENC_FLAG_SIGALGS
118 | SSL_ENC_FLAG_SHA256_PRF | SSL_ENC_FLAG_TLS1_2_CIPHERS,
119 DTLS1_HM_HEADER_LENGTH,
120 dtls1_set_handshake_header,
121 dtls1_handshake_write
124 long dtls1_default_timeout(void)
127 * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for
128 * http, the cache would over fill
130 return (60 * 60 * 2);
133 int dtls1_new(SSL *s)
137 if (!DTLS_RECORD_LAYER_new(&s->rlayer)) {
143 if ((d1 = OPENSSL_zalloc(sizeof(*d1))) == NULL) {
148 d1->buffered_messages = pqueue_new();
149 d1->sent_messages = pqueue_new();
152 d1->cookie_len = sizeof(s->d1->cookie);
158 if (!d1->buffered_messages || !d1->sent_messages) {
159 pqueue_free(d1->buffered_messages);
160 pqueue_free(d1->sent_messages);
167 s->method->ssl_clear(s);
171 static void dtls1_clear_queues(SSL *s)
174 hm_fragment *frag = NULL;
176 while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) {
177 frag = (hm_fragment *)item->data;
178 dtls1_hm_fragment_free(frag);
182 while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) {
183 frag = (hm_fragment *)item->data;
184 dtls1_hm_fragment_free(frag);
189 void dtls1_free(SSL *s)
191 DTLS_RECORD_LAYER_free(&s->rlayer);
195 dtls1_clear_queues(s);
197 pqueue_free(s->d1->buffered_messages);
198 pqueue_free(s->d1->sent_messages);
204 void dtls1_clear(SSL *s)
206 pqueue buffered_messages;
207 pqueue sent_messages;
209 unsigned int link_mtu;
211 DTLS_RECORD_LAYER_clear(&s->rlayer);
214 buffered_messages = s->d1->buffered_messages;
215 sent_messages = s->d1->sent_messages;
217 link_mtu = s->d1->link_mtu;
219 dtls1_clear_queues(s);
221 memset(s->d1, 0, sizeof(*s->d1));
224 s->d1->cookie_len = sizeof(s->d1->cookie);
227 if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) {
229 s->d1->link_mtu = link_mtu;
232 s->d1->buffered_messages = buffered_messages;
233 s->d1->sent_messages = sent_messages;
237 if (s->options & SSL_OP_CISCO_ANYCONNECT)
238 s->client_version = s->version = DTLS1_BAD_VER;
239 else if (s->method->version == DTLS_ANY_VERSION)
240 s->version = DTLS1_2_VERSION;
242 s->version = s->method->version;
245 long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
250 case DTLS_CTRL_GET_TIMEOUT:
251 if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) {
255 case DTLS_CTRL_HANDLE_TIMEOUT:
256 ret = dtls1_handle_timeout(s);
258 case DTLS_CTRL_LISTEN:
259 ret = dtls1_listen(s, parg);
261 case SSL_CTRL_CHECK_PROTO_VERSION:
263 * For library-internal use; checks that the current protocol is the
264 * highest enabled version (according to s->ctx->method, as version
265 * negotiation may have changed s->method).
267 if (s->version == s->ctx->method->version)
270 * Apparently we're using a version-flexible SSL_METHOD (not at its
271 * highest protocol version).
273 if (s->ctx->method->version == DTLS_method()->version) {
274 #if DTLS_MAX_VERSION != DTLS1_2_VERSION
275 # error Code needs update for DTLS_method() support beyond DTLS1_2_VERSION.
277 if (!(s->options & SSL_OP_NO_DTLSv1_2))
278 return s->version == DTLS1_2_VERSION;
279 if (!(s->options & SSL_OP_NO_DTLSv1))
280 return s->version == DTLS1_VERSION;
282 return 0; /* Unexpected state; fail closed. */
283 case DTLS_CTRL_SET_LINK_MTU:
284 if (larg < (long)dtls1_link_min_mtu())
286 s->d1->link_mtu = larg;
288 case DTLS_CTRL_GET_LINK_MIN_MTU:
289 return (long)dtls1_link_min_mtu();
290 case SSL_CTRL_SET_MTU:
292 * We may not have a BIO set yet so can't call dtls1_min_mtu()
293 * We'll have to make do with dtls1_link_min_mtu() and max overhead
295 if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD)
300 ret = ssl3_ctrl(s, cmd, larg, parg);
307 * As it's impossible to use stream ciphers in "datagram" mode, this
308 * simple filter is designed to disengage them in DTLS. Unfortunately
309 * there is no universal way to identify stream SSL_CIPHER, so we have
310 * to explicitly list their SSL_* codes. Currently RC4 is the only one
311 * available, but if new ones emerge, they will have to be added...
313 const SSL_CIPHER *dtls1_get_cipher(unsigned int u)
315 const SSL_CIPHER *ciph = ssl3_get_cipher(u);
318 if (ciph->algorithm_enc == SSL_RC4)
325 void dtls1_start_timer(SSL *s)
327 #ifndef OPENSSL_NO_SCTP
328 /* Disable timer for SCTP */
329 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
330 memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
335 /* If timer is not set, initialize duration with 1 second */
336 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
337 s->d1->timeout_duration = 1;
340 /* Set timeout to current time */
341 get_current_time(&(s->d1->next_timeout));
343 /* Add duration to current time */
344 s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
345 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
346 &(s->d1->next_timeout));
349 struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft)
351 struct timeval timenow;
353 /* If no timeout is set, just return NULL */
354 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
358 /* Get current time */
359 get_current_time(&timenow);
361 /* If timer already expired, set remaining time to 0 */
362 if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
363 (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
364 s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
365 memset(timeleft, 0, sizeof(*timeleft));
369 /* Calculate time left until timer expires */
370 memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
371 timeleft->tv_sec -= timenow.tv_sec;
372 timeleft->tv_usec -= timenow.tv_usec;
373 if (timeleft->tv_usec < 0) {
375 timeleft->tv_usec += 1000000;
379 * If remaining time is less than 15 ms, set it to 0 to prevent issues
380 * because of small devergences with socket timeouts.
382 if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
383 memset(timeleft, 0, sizeof(*timeleft));
389 int dtls1_is_timer_expired(SSL *s)
391 struct timeval timeleft;
393 /* Get time left until timeout, return false if no timer running */
394 if (dtls1_get_timeout(s, &timeleft) == NULL) {
398 /* Return false if timer is not expired yet */
399 if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
403 /* Timer expired, so return true */
407 void dtls1_double_timeout(SSL *s)
409 s->d1->timeout_duration *= 2;
410 if (s->d1->timeout_duration > 60)
411 s->d1->timeout_duration = 60;
412 dtls1_start_timer(s);
415 void dtls1_stop_timer(SSL *s)
417 /* Reset everything */
418 memset(&s->d1->timeout, 0, sizeof(s->d1->timeout));
419 memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
420 s->d1->timeout_duration = 1;
421 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
422 &(s->d1->next_timeout));
423 /* Clear retransmission buffer */
424 dtls1_clear_record_buffer(s);
427 int dtls1_check_timeout_num(SSL *s)
431 s->d1->timeout.num_alerts++;
433 /* Reduce MTU after 2 unsuccessful retransmissions */
434 if (s->d1->timeout.num_alerts > 2
435 && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
437 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0,
439 if (mtu < s->d1->mtu)
443 if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) {
444 /* fail the connection, enough alerts have been sent */
445 SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM, SSL_R_READ_TIMEOUT_EXPIRED);
452 int dtls1_handle_timeout(SSL *s)
454 /* if no timer is expired, don't do anything */
455 if (!dtls1_is_timer_expired(s)) {
459 dtls1_double_timeout(s);
461 if (dtls1_check_timeout_num(s) < 0)
464 s->d1->timeout.read_timeouts++;
465 if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) {
466 s->d1->timeout.read_timeouts = 1;
468 #ifndef OPENSSL_NO_HEARTBEATS
469 if (s->tlsext_hb_pending) {
470 s->tlsext_hb_pending = 0;
471 return dtls1_heartbeat(s);
475 dtls1_start_timer(s);
476 return dtls1_retransmit_buffered_messages(s);
479 static void get_current_time(struct timeval *t)
489 SystemTimeToFileTime(&st, &now.ft);
491 now.ul -= 116444736000000000ULL;
493 now.ul -= 116444736000000000UI64; /* re-bias to 1/1/1970 */
495 t->tv_sec = (long)(now.ul / 10000000);
496 t->tv_usec = ((int)(now.ul % 10000000)) / 10;
497 #elif defined(OPENSSL_SYS_VMS)
500 t->tv_sec = (long)tb.time;
501 t->tv_usec = (long)tb.millitm * 1000;
503 gettimeofday(t, NULL);
508 #define LISTEN_SUCCESS 2
509 #define LISTEN_SEND_VERIFY_REQUEST 1
512 int dtls1_listen(SSL *s, struct sockaddr *client)
514 int next, n, ret = 0, clearpkt = 0;
515 unsigned char cookie[DTLS1_COOKIE_LENGTH];
516 unsigned char seq[SEQ_NUM_SIZE];
517 unsigned char *data, *p, *buf;
518 unsigned long reclen, fragoff, fraglen, msglen;
519 unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen;
522 struct sockaddr_storage tmpclient;
523 PACKET pkt, msgpkt, msgpayload, session, cookiepkt;
525 /* Ensure there is no state left over from a previous invocation */
531 rbio = SSL_get_rbio(s);
532 wbio = SSL_get_wbio(s);
535 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_BIO_NOT_SET);
540 * We only peek at incoming ClientHello's until we're sure we are going to
541 * to respond with a HelloVerifyRequest. If its a ClientHello with a valid
542 * cookie then we leave it in the BIO for dtls1_accept to handle.
544 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);
547 * Note: This check deliberately excludes DTLS1_BAD_VER because that version
548 * requires the MAC to be calculated *including* the first ClientHello
549 * (without the cookie). Since DTLSv1_listen is stateless that cannot be
550 * supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via
553 if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
554 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_UNSUPPORTED_SSL_VERSION);
558 if (s->init_buf == NULL) {
559 if ((bufm = BUF_MEM_new()) == NULL) {
560 SSLerr(SSL_F_DTLS1_LISTEN, ERR_R_MALLOC_FAILURE);
564 if (!BUF_MEM_grow(bufm, SSL3_RT_MAX_PLAIN_LENGTH)) {
566 SSLerr(SSL_F_DTLS1_LISTEN, ERR_R_MALLOC_FAILURE);
571 buf = (unsigned char *)s->init_buf->data;
578 * Technically a ClientHello could be SSL3_RT_MAX_PLAIN_LENGTH
579 * + DTLS1_RT_HEADER_LENGTH bytes long. Normally init_buf does not store
580 * the record header as well, but we do here. We've set up init_buf to
581 * be the standard size for simplicity. In practice we shouldn't ever
582 * receive a ClientHello as long as this. If we do it will get dropped
583 * in the record length check below.
585 n = BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
588 if(BIO_should_retry(rbio)) {
589 /* Non-blocking IO */
595 /* If we hit any problems we need to clear this packet from the BIO */
598 if (!PACKET_buf_init(&pkt, buf, n)) {
599 SSLerr(SSL_F_DTLS1_LISTEN, ERR_R_INTERNAL_ERROR);
604 * Parse the received record. If there are any problems with it we just
605 * dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is
606 * resilient in the face of invalid records (e.g., invalid formatting,
607 * length, MAC, etc.). In general, invalid records SHOULD be silently
608 * discarded, thus preserving the association; however, an error MAY be
609 * logged for diagnostic purposes."
612 /* this packet contained a partial record, dump it */
613 if (n < DTLS1_RT_HEADER_LENGTH) {
614 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_RECORD_TOO_SMALL);
619 s->msg_callback(0, 0, SSL3_RT_HEADER, buf,
620 DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
622 /* Get the record header */
623 if (!PACKET_get_1(&pkt, &rectype)
624 || !PACKET_get_1(&pkt, &versmajor)) {
625 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_LENGTH_MISMATCH);
629 if (rectype != SSL3_RT_HANDSHAKE) {
630 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
635 * Check record version number. We only check that the major version is
638 if (versmajor != DTLS1_VERSION_MAJOR) {
639 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
643 if (!PACKET_forward(&pkt, 1)
644 /* Save the sequence number: 64 bits, with top 2 bytes = epoch */
645 || !PACKET_copy_bytes(&pkt, seq, SEQ_NUM_SIZE)
646 || !PACKET_get_length_prefixed_2(&pkt, &msgpkt)
647 || PACKET_remaining(&pkt) != 0) {
648 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_LENGTH_MISMATCH);
652 /* This is an initial ClientHello so the epoch has to be 0 */
653 if (seq[0] != 0 || seq[1] != 0) {
654 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
658 /* Get a pointer to the raw message for the later callback */
659 data = PACKET_data(&msgpkt);
661 /* Finished processing the record header, now process the message */
662 if (!PACKET_get_1(&msgpkt, &msgtype)
663 || !PACKET_get_net_3(&msgpkt, &msglen)
664 || !PACKET_get_net_2(&msgpkt, &msgseq)
665 || !PACKET_get_net_3(&msgpkt, &fragoff)
666 || !PACKET_get_net_3(&msgpkt, &fraglen)
667 || !PACKET_get_sub_packet(&msgpkt, &msgpayload, msglen)
668 || PACKET_remaining(&msgpkt) != 0) {
669 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_LENGTH_MISMATCH);
673 if (msgtype != SSL3_MT_CLIENT_HELLO) {
674 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
678 /* Message sequence number can only be 0 or 1 */
680 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_INVALID_SEQUENCE_NUMBER);
684 /* We don't support a fragmented ClientHello whilst listening */
685 if (fragoff != 0 || fraglen != msglen) {
686 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_FRAGMENTED_CLIENT_HELLO);
691 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, data,
692 msglen + DTLS1_HM_HEADER_LENGTH, s,
693 s->msg_callback_arg);
695 if (!PACKET_get_net_2(&msgpayload, &clientvers)) {
696 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_LENGTH_MISMATCH);
701 * Verify client version is supported
703 if ((clientvers > (unsigned int)s->method->version &&
704 s->method->version != DTLS_ANY_VERSION)) {
705 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_WRONG_VERSION_NUMBER);
709 if (!PACKET_forward(&msgpayload, SSL3_RANDOM_SIZE)
710 || !PACKET_get_length_prefixed_1(&msgpayload, &session)
711 || !PACKET_get_length_prefixed_1(&msgpayload, &cookiepkt)) {
712 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_LENGTH_MISMATCH);
717 * Check if we have a cookie or not. If not we need to send a
718 * HelloVerifyRequest.
720 if (PACKET_remaining(&cookiepkt) == 0) {
721 next = LISTEN_SEND_VERIFY_REQUEST;
724 * We have a cookie, so lets check it.
726 if (s->ctx->app_verify_cookie_cb == NULL) {
727 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_NO_VERIFY_COOKIE_CALLBACK);
731 if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&cookiepkt),
732 PACKET_remaining(&cookiepkt)) ==
735 * We treat invalid cookies in the same was as no cookie as
738 next = LISTEN_SEND_VERIFY_REQUEST;
740 /* Cookie verification succeeded */
741 next = LISTEN_SUCCESS;
745 if (next == LISTEN_SEND_VERIFY_REQUEST) {
747 * There was no cookie in the ClientHello so we need to send a
748 * HelloVerifyRequest. If this fails we do not worry about trying
749 * to resend, we just drop it.
753 * Dump the read packet, we don't need it any more. Ignore return
756 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL);
757 BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
758 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);
760 /* Generate the cookie */
761 if (s->ctx->app_gen_cookie_cb == NULL ||
762 s->ctx->app_gen_cookie_cb(s, cookie, &cookielen) == 0 ||
764 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
769 p = &buf[DTLS1_RT_HEADER_LENGTH];
770 msglen = dtls_raw_hello_verify_request(p + DTLS1_HM_HEADER_LENGTH,
773 *p++ = DTLS1_MT_HELLO_VERIFY_REQUEST;
778 /* Message sequence number is always 0 for a HelloVerifyRequest */
782 * We never fragment a HelloVerifyRequest, so fragment offset is 0
783 * and fragment length is message length
788 /* Set reclen equal to length of whole handshake message */
789 reclen = msglen + DTLS1_HM_HEADER_LENGTH;
791 /* Add the record header */
794 *(p++) = SSL3_RT_HANDSHAKE;
796 * Special case: for hello verify request, client version 1.0 and we
797 * haven't decided which version to use yet send back using version
798 * 1.0 header: otherwise some clients will ignore it.
800 if (s->method->version == DTLS_ANY_VERSION) {
801 *(p++) = DTLS1_VERSION >> 8;
802 *(p++) = DTLS1_VERSION & 0xff;
804 *(p++) = s->version >> 8;
805 *(p++) = s->version & 0xff;
809 * Record sequence number is always the same as in the received
812 memcpy(p, seq, SEQ_NUM_SIZE);
819 * Set reclen equal to length of whole record including record
822 reclen += DTLS1_RT_HEADER_LENGTH;
825 s->msg_callback(1, 0, SSL3_RT_HEADER, buf,
826 DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
829 * This is unneccessary if rbio and wbio are one and the same - but
832 if(BIO_dgram_get_peer(rbio, &tmpclient) <= 0
833 || BIO_dgram_set_peer(wbio, &tmpclient) <= 0) {
834 SSLerr(SSL_F_DTLS1_LISTEN, ERR_R_INTERNAL_ERROR);
838 if (BIO_write(wbio, buf, reclen) < (int)reclen) {
839 if(BIO_should_retry(wbio)) {
841 * Non-blocking IO...but we're stateless, so we're just
842 * going to drop this packet.
849 if (BIO_flush(wbio) <= 0) {
850 if(BIO_should_retry(wbio)) {
852 * Non-blocking IO...but we're stateless, so we're just
853 * going to drop this packet.
860 } while (next != LISTEN_SUCCESS);
863 * Set expected sequence numbers to continue the handshake.
865 s->d1->handshake_read_seq = 1;
866 s->d1->handshake_write_seq = 1;
867 s->d1->next_handshake_write_seq = 1;
868 DTLS_RECORD_LAYER_set_write_sequence(&s->rlayer, seq);
871 * We are doing cookie exchange, so make sure we set that option in the
874 SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
877 * Tell the state machine that we've done the initial hello verify
880 ossl_statem_set_hello_verify_done(s);
882 if(BIO_dgram_get_peer(rbio, client) <= 0) {
883 SSLerr(SSL_F_DTLS1_LISTEN, ERR_R_INTERNAL_ERROR);
890 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL);
892 /* Dump this packet. Ignore return value */
893 BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
898 static int dtls1_set_handshake_header(SSL *s, int htype, unsigned long len)
900 unsigned char *p = (unsigned char *)s->init_buf->data;
901 dtls1_set_message_header(s, p, htype, len, 0, len);
902 s->init_num = (int)len + DTLS1_HM_HEADER_LENGTH;
904 /* Buffer the message to handle re-xmits */
906 if (!dtls1_buffer_message(s, 0))
912 static int dtls1_handshake_write(SSL *s)
914 return dtls1_do_write(s, SSL3_RT_HANDSHAKE);
917 #ifndef OPENSSL_NO_HEARTBEATS
918 int dtls1_process_heartbeat(SSL *s, unsigned char *p, unsigned int length)
921 unsigned short hbtype;
922 unsigned int payload;
923 unsigned int padding = 16; /* Use minimum padding */
926 s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
927 p, length, s, s->msg_callback_arg);
929 /* Read type and payload length first */
930 if (1 + 2 + 16 > length)
931 return 0; /* silently discard */
932 if (length > SSL3_RT_MAX_PLAIN_LENGTH)
933 return 0; /* silently discard per RFC 6520 sec. 4 */
937 if (1 + 2 + payload + 16 > length)
938 return 0; /* silently discard per RFC 6520 sec. 4 */
941 if (hbtype == TLS1_HB_REQUEST) {
942 unsigned char *buffer, *bp;
943 unsigned int write_length = 1 /* heartbeat type */ +
944 2 /* heartbeat length */ +
948 if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
952 * Allocate memory for the response, size is 1 byte message type,
953 * plus 2 bytes payload length, plus payload, plus padding
955 buffer = OPENSSL_malloc(write_length);
960 /* Enter response type, length and copy payload */
961 *bp++ = TLS1_HB_RESPONSE;
963 memcpy(bp, pl, payload);
966 if (RAND_bytes(bp, padding) <= 0) {
967 OPENSSL_free(buffer);
971 r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
973 if (r >= 0 && s->msg_callback)
974 s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
975 buffer, write_length, s, s->msg_callback_arg);
977 OPENSSL_free(buffer);
981 } else if (hbtype == TLS1_HB_RESPONSE) {
985 * We only send sequence numbers (2 bytes unsigned int), and 16
986 * random bytes, so we just try to read the sequence number
990 if (payload == 18 && seq == s->tlsext_hb_seq) {
993 s->tlsext_hb_pending = 0;
1000 int dtls1_heartbeat(SSL *s)
1002 unsigned char *buf, *p;
1004 unsigned int payload = 18; /* Sequence number + random bytes */
1005 unsigned int padding = 16; /* Use minimum padding */
1007 /* Only send if peer supports and accepts HB requests... */
1008 if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
1009 s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS) {
1010 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
1014 /* ...and there is none in flight yet... */
1015 if (s->tlsext_hb_pending) {
1016 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PENDING);
1020 /* ...and no handshake in progress. */
1021 if (SSL_in_init(s) || ossl_statem_get_in_handshake(s)) {
1022 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_UNEXPECTED_MESSAGE);
1027 * Create HeartBeat message, we just use a sequence number
1028 * as payload to distuingish different messages and add
1029 * some random stuff.
1030 * - Message Type, 1 byte
1031 * - Payload Length, 2 bytes (unsigned int)
1032 * - Payload, the sequence number (2 bytes uint)
1033 * - Payload, random bytes (16 bytes uint)
1036 buf = OPENSSL_malloc(1 + 2 + payload + padding);
1038 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_MALLOC_FAILURE);
1043 *p++ = TLS1_HB_REQUEST;
1044 /* Payload length (18 bytes here) */
1046 /* Sequence number */
1047 s2n(s->tlsext_hb_seq, p);
1048 /* 16 random bytes */
1049 if (RAND_bytes(p, 16) <= 0) {
1050 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR);
1054 /* Random padding */
1055 if (RAND_bytes(p, padding) <= 0) {
1056 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR);
1060 ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
1062 if (s->msg_callback)
1063 s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1064 buf, 3 + payload + padding,
1065 s, s->msg_callback_arg);
1067 dtls1_start_timer(s);
1068 s->tlsext_hb_pending = 1;
1078 int dtls1_shutdown(SSL *s)
1081 #ifndef OPENSSL_NO_SCTP
1084 wbio = SSL_get_wbio(s);
1085 if (wbio != NULL && BIO_dgram_is_sctp(wbio) &&
1086 !(s->shutdown & SSL_SENT_SHUTDOWN)) {
1087 ret = BIO_dgram_sctp_wait_for_dry(wbio);
1092 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1,
1096 ret = ssl3_shutdown(s);
1097 #ifndef OPENSSL_NO_SCTP
1098 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
1103 int dtls1_query_mtu(SSL *s)
1105 if (s->d1->link_mtu) {
1107 s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
1108 s->d1->link_mtu = 0;
1111 /* AHA! Figure out the MTU, and stick to the right size */
1112 if (s->d1->mtu < dtls1_min_mtu(s)) {
1113 if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
1115 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
1118 * I've seen the kernel return bogus numbers when it doesn't know
1119 * (initial write), so just make sure we have a reasonable number
1121 if (s->d1->mtu < dtls1_min_mtu(s)) {
1122 /* Set to min mtu */
1123 s->d1->mtu = dtls1_min_mtu(s);
1124 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
1133 static unsigned int dtls1_link_min_mtu(void)
1135 return (g_probable_mtu[(sizeof(g_probable_mtu) /
1136 sizeof(g_probable_mtu[0])) - 1]);
1139 unsigned int dtls1_min_mtu(SSL *s)
1141 return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));