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);
81 /* XDTLS: figure out the right values */
82 static const unsigned int g_probable_mtu[] = { 1500, 512, 256 };
84 const SSL3_ENC_METHOD DTLSv1_enc_data = {
88 tls1_generate_master_secret,
89 tls1_change_cipher_state,
90 tls1_final_finish_mac,
91 TLS1_FINISH_MAC_LENGTH,
93 TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
94 TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
96 tls1_export_keying_material,
97 SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV,
98 DTLS1_HM_HEADER_LENGTH,
99 dtls1_set_handshake_header,
100 dtls1_handshake_write
103 const SSL3_ENC_METHOD DTLSv1_2_enc_data = {
106 tls1_setup_key_block,
107 tls1_generate_master_secret,
108 tls1_change_cipher_state,
109 tls1_final_finish_mac,
110 TLS1_FINISH_MAC_LENGTH,
111 tls1_cert_verify_mac,
112 TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
113 TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
115 tls1_export_keying_material,
116 SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV | SSL_ENC_FLAG_SIGALGS
117 | SSL_ENC_FLAG_SHA256_PRF | SSL_ENC_FLAG_TLS1_2_CIPHERS,
118 DTLS1_HM_HEADER_LENGTH,
119 dtls1_set_handshake_header,
120 dtls1_handshake_write
123 long dtls1_default_timeout(void)
126 * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for
127 * http, the cache would over fill
129 return (60 * 60 * 2);
132 int dtls1_new(SSL *s)
136 if (!DTLS_RECORD_LAYER_new(&s->rlayer)) {
142 if ((d1 = OPENSSL_zalloc(sizeof(*d1))) == NULL) {
147 d1->buffered_messages = pqueue_new();
148 d1->sent_messages = pqueue_new();
151 d1->cookie_len = sizeof(s->d1->cookie);
157 if (!d1->buffered_messages || !d1->sent_messages) {
158 pqueue_free(d1->buffered_messages);
159 pqueue_free(d1->sent_messages);
166 s->method->ssl_clear(s);
170 static void dtls1_clear_queues(SSL *s)
173 hm_fragment *frag = NULL;
175 while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) {
176 frag = (hm_fragment *)item->data;
177 dtls1_hm_fragment_free(frag);
181 while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) {
182 frag = (hm_fragment *)item->data;
183 dtls1_hm_fragment_free(frag);
188 void dtls1_free(SSL *s)
190 DTLS_RECORD_LAYER_free(&s->rlayer);
194 dtls1_clear_queues(s);
196 pqueue_free(s->d1->buffered_messages);
197 pqueue_free(s->d1->sent_messages);
203 void dtls1_clear(SSL *s)
205 pqueue buffered_messages;
206 pqueue sent_messages;
208 unsigned int link_mtu;
210 DTLS_RECORD_LAYER_clear(&s->rlayer);
213 buffered_messages = s->d1->buffered_messages;
214 sent_messages = s->d1->sent_messages;
216 link_mtu = s->d1->link_mtu;
218 dtls1_clear_queues(s);
220 memset(s->d1, 0, sizeof(*s->d1));
223 s->d1->cookie_len = sizeof(s->d1->cookie);
226 if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) {
228 s->d1->link_mtu = link_mtu;
231 s->d1->buffered_messages = buffered_messages;
232 s->d1->sent_messages = sent_messages;
236 if (s->options & SSL_OP_CISCO_ANYCONNECT)
237 s->client_version = s->version = DTLS1_BAD_VER;
238 else if (s->method->version == DTLS_ANY_VERSION)
239 s->version = DTLS1_2_VERSION;
241 s->version = s->method->version;
244 long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
249 case DTLS_CTRL_GET_TIMEOUT:
250 if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) {
254 case DTLS_CTRL_HANDLE_TIMEOUT:
255 ret = dtls1_handle_timeout(s);
257 case DTLS_CTRL_LISTEN:
258 ret = dtls1_listen(s, parg);
260 case SSL_CTRL_CHECK_PROTO_VERSION:
262 * For library-internal use; checks that the current protocol is the
263 * highest enabled version (according to s->ctx->method, as version
264 * negotiation may have changed s->method).
266 if (s->version == s->ctx->method->version)
269 * Apparently we're using a version-flexible SSL_METHOD (not at its
270 * highest protocol version).
272 if (s->ctx->method->version == DTLS_method()->version) {
273 #if DTLS_MAX_VERSION != DTLS1_2_VERSION
274 # error Code needs update for DTLS_method() support beyond DTLS1_2_VERSION.
276 if (!(s->options & SSL_OP_NO_DTLSv1_2))
277 return s->version == DTLS1_2_VERSION;
278 if (!(s->options & SSL_OP_NO_DTLSv1))
279 return s->version == DTLS1_VERSION;
281 return 0; /* Unexpected state; fail closed. */
282 case DTLS_CTRL_SET_LINK_MTU:
283 if (larg < (long)dtls1_link_min_mtu())
285 s->d1->link_mtu = larg;
287 case DTLS_CTRL_GET_LINK_MIN_MTU:
288 return (long)dtls1_link_min_mtu();
289 case SSL_CTRL_SET_MTU:
291 * We may not have a BIO set yet so can't call dtls1_min_mtu()
292 * We'll have to make do with dtls1_link_min_mtu() and max overhead
294 if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD)
299 ret = ssl3_ctrl(s, cmd, larg, parg);
306 * As it's impossible to use stream ciphers in "datagram" mode, this
307 * simple filter is designed to disengage them in DTLS. Unfortunately
308 * there is no universal way to identify stream SSL_CIPHER, so we have
309 * to explicitly list their SSL_* codes. Currently RC4 is the only one
310 * available, but if new ones emerge, they will have to be added...
312 const SSL_CIPHER *dtls1_get_cipher(unsigned int u)
314 const SSL_CIPHER *ciph = ssl3_get_cipher(u);
317 if (ciph->algorithm_enc == SSL_RC4)
324 void dtls1_start_timer(SSL *s)
326 #ifndef OPENSSL_NO_SCTP
327 /* Disable timer for SCTP */
328 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
329 memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
334 /* If timer is not set, initialize duration with 1 second */
335 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
336 s->d1->timeout_duration = 1;
339 /* Set timeout to current time */
340 get_current_time(&(s->d1->next_timeout));
342 /* Add duration to current time */
343 s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
344 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
345 &(s->d1->next_timeout));
348 struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft)
350 struct timeval timenow;
352 /* If no timeout is set, just return NULL */
353 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
357 /* Get current time */
358 get_current_time(&timenow);
360 /* If timer already expired, set remaining time to 0 */
361 if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
362 (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
363 s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
364 memset(timeleft, 0, sizeof(*timeleft));
368 /* Calculate time left until timer expires */
369 memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
370 timeleft->tv_sec -= timenow.tv_sec;
371 timeleft->tv_usec -= timenow.tv_usec;
372 if (timeleft->tv_usec < 0) {
374 timeleft->tv_usec += 1000000;
378 * If remaining time is less than 15 ms, set it to 0 to prevent issues
379 * because of small devergences with socket timeouts.
381 if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
382 memset(timeleft, 0, sizeof(*timeleft));
388 int dtls1_is_timer_expired(SSL *s)
390 struct timeval timeleft;
392 /* Get time left until timeout, return false if no timer running */
393 if (dtls1_get_timeout(s, &timeleft) == NULL) {
397 /* Return false if timer is not expired yet */
398 if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
402 /* Timer expired, so return true */
406 void dtls1_double_timeout(SSL *s)
408 s->d1->timeout_duration *= 2;
409 if (s->d1->timeout_duration > 60)
410 s->d1->timeout_duration = 60;
411 dtls1_start_timer(s);
414 void dtls1_stop_timer(SSL *s)
416 /* Reset everything */
417 memset(&s->d1->timeout, 0, sizeof(s->d1->timeout));
418 memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
419 s->d1->timeout_duration = 1;
420 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
421 &(s->d1->next_timeout));
422 /* Clear retransmission buffer */
423 dtls1_clear_record_buffer(s);
426 int dtls1_check_timeout_num(SSL *s)
430 s->d1->timeout.num_alerts++;
432 /* Reduce MTU after 2 unsuccessful retransmissions */
433 if (s->d1->timeout.num_alerts > 2
434 && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
436 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0,
438 if (mtu < s->d1->mtu)
442 if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) {
443 /* fail the connection, enough alerts have been sent */
444 SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM, SSL_R_READ_TIMEOUT_EXPIRED);
451 int dtls1_handle_timeout(SSL *s)
453 /* if no timer is expired, don't do anything */
454 if (!dtls1_is_timer_expired(s)) {
458 dtls1_double_timeout(s);
460 if (dtls1_check_timeout_num(s) < 0)
463 s->d1->timeout.read_timeouts++;
464 if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) {
465 s->d1->timeout.read_timeouts = 1;
467 #ifndef OPENSSL_NO_HEARTBEATS
468 if (s->tlsext_hb_pending) {
469 s->tlsext_hb_pending = 0;
470 return dtls1_heartbeat(s);
474 dtls1_start_timer(s);
475 return dtls1_retransmit_buffered_messages(s);
478 static void get_current_time(struct timeval *t)
488 SystemTimeToFileTime(&st, &now.ft);
490 now.ul -= 116444736000000000ULL;
492 now.ul -= 116444736000000000UI64; /* re-bias to 1/1/1970 */
494 t->tv_sec = (long)(now.ul / 10000000);
495 t->tv_usec = ((int)(now.ul % 10000000)) / 10;
496 #elif defined(OPENSSL_SYS_VMS)
499 t->tv_sec = (long)tb.time;
500 t->tv_usec = (long)tb.millitm * 1000;
502 gettimeofday(t, NULL);
507 #define LISTEN_SUCCESS 2
508 #define LISTEN_SEND_VERIFY_REQUEST 1
511 int dtls1_listen(SSL *s, struct sockaddr *client)
513 int next, n, ret = 0, clearpkt = 0;
514 unsigned char cookie[DTLS1_COOKIE_LENGTH];
515 unsigned char seq[SEQ_NUM_SIZE];
516 unsigned char *data, *p, *buf;
517 unsigned long reclen, fragoff, fraglen, msglen;
518 unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen;
521 struct sockaddr_storage tmpclient;
522 PACKET pkt, msgpkt, msgpayload, session, cookiepkt;
524 /* Ensure there is no state left over from a previous invocation */
530 rbio = SSL_get_rbio(s);
531 wbio = SSL_get_wbio(s);
534 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_BIO_NOT_SET);
539 * We only peek at incoming ClientHello's until we're sure we are going to
540 * to respond with a HelloVerifyRequest. If its a ClientHello with a valid
541 * cookie then we leave it in the BIO for dtls1_accept to handle.
543 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);
546 * Note: This check deliberately excludes DTLS1_BAD_VER because that version
547 * requires the MAC to be calculated *including* the first ClientHello
548 * (without the cookie). Since DTLSv1_listen is stateless that cannot be
549 * supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via
552 if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
553 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_UNSUPPORTED_SSL_VERSION);
557 if (s->init_buf == NULL) {
558 if ((bufm = BUF_MEM_new()) == NULL) {
559 SSLerr(SSL_F_DTLS1_LISTEN, ERR_R_MALLOC_FAILURE);
563 if (!BUF_MEM_grow(bufm, SSL3_RT_MAX_PLAIN_LENGTH)) {
565 SSLerr(SSL_F_DTLS1_LISTEN, ERR_R_MALLOC_FAILURE);
570 buf = (unsigned char *)s->init_buf->data;
577 * Technically a ClientHello could be SSL3_RT_MAX_PLAIN_LENGTH
578 * + DTLS1_RT_HEADER_LENGTH bytes long. Normally init_buf does not store
579 * the record header as well, but we do here. We've set up init_buf to
580 * be the standard size for simplicity. In practice we shouldn't ever
581 * receive a ClientHello as long as this. If we do it will get dropped
582 * in the record length check below.
584 n = BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
587 if(BIO_should_retry(rbio)) {
588 /* Non-blocking IO */
594 /* If we hit any problems we need to clear this packet from the BIO */
597 if (!PACKET_buf_init(&pkt, buf, n)) {
598 SSLerr(SSL_F_DTLS1_LISTEN, ERR_R_INTERNAL_ERROR);
603 * Parse the received record. If there are any problems with it we just
604 * dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is
605 * resilient in the face of invalid records (e.g., invalid formatting,
606 * length, MAC, etc.). In general, invalid records SHOULD be silently
607 * discarded, thus preserving the association; however, an error MAY be
608 * logged for diagnostic purposes."
611 /* this packet contained a partial record, dump it */
612 if (n < DTLS1_RT_HEADER_LENGTH) {
613 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_RECORD_TOO_SMALL);
618 s->msg_callback(0, 0, SSL3_RT_HEADER, buf,
619 DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
621 /* Get the record header */
622 if (!PACKET_get_1(&pkt, &rectype)
623 || !PACKET_get_1(&pkt, &versmajor)) {
624 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_LENGTH_MISMATCH);
628 if (rectype != SSL3_RT_HANDSHAKE) {
629 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
634 * Check record version number. We only check that the major version is
637 if (versmajor != DTLS1_VERSION_MAJOR) {
638 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
642 if (!PACKET_forward(&pkt, 1)
643 /* Save the sequence number: 64 bits, with top 2 bytes = epoch */
644 || !PACKET_copy_bytes(&pkt, seq, SEQ_NUM_SIZE)
645 || !PACKET_get_length_prefixed_2(&pkt, &msgpkt)
646 || PACKET_remaining(&pkt) != 0) {
647 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_LENGTH_MISMATCH);
651 /* This is an initial ClientHello so the epoch has to be 0 */
652 if (seq[0] != 0 || seq[1] != 0) {
653 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
657 /* Get a pointer to the raw message for the later callback */
658 data = PACKET_data(&msgpkt);
660 /* Finished processing the record header, now process the message */
661 if (!PACKET_get_1(&msgpkt, &msgtype)
662 || !PACKET_get_net_3(&msgpkt, &msglen)
663 || !PACKET_get_net_2(&msgpkt, &msgseq)
664 || !PACKET_get_net_3(&msgpkt, &fragoff)
665 || !PACKET_get_net_3(&msgpkt, &fraglen)
666 || !PACKET_get_sub_packet(&msgpkt, &msgpayload, msglen)
667 || PACKET_remaining(&msgpkt) != 0) {
668 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_LENGTH_MISMATCH);
672 if (msgtype != SSL3_MT_CLIENT_HELLO) {
673 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
677 /* Message sequence number can only be 0 or 1 */
679 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_INVALID_SEQUENCE_NUMBER);
683 /* We don't support a fragmented ClientHello whilst listening */
684 if (fragoff != 0 || fraglen != msglen) {
685 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_FRAGMENTED_CLIENT_HELLO);
690 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, data,
691 msglen + DTLS1_HM_HEADER_LENGTH, s,
692 s->msg_callback_arg);
694 if (!PACKET_get_net_2(&msgpayload, &clientvers)) {
695 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_LENGTH_MISMATCH);
700 * Verify client version is supported
702 if ((clientvers > (unsigned int)s->method->version &&
703 s->method->version != DTLS_ANY_VERSION)) {
704 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_WRONG_VERSION_NUMBER);
708 if (!PACKET_forward(&msgpayload, SSL3_RANDOM_SIZE)
709 || !PACKET_get_length_prefixed_1(&msgpayload, &session)
710 || !PACKET_get_length_prefixed_1(&msgpayload, &cookiepkt)) {
711 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_LENGTH_MISMATCH);
716 * Check if we have a cookie or not. If not we need to send a
717 * HelloVerifyRequest.
719 if (PACKET_remaining(&cookiepkt) == 0) {
720 next = LISTEN_SEND_VERIFY_REQUEST;
723 * We have a cookie, so lets check it.
725 if (s->ctx->app_verify_cookie_cb == NULL) {
726 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_NO_VERIFY_COOKIE_CALLBACK);
730 if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&cookiepkt),
731 PACKET_remaining(&cookiepkt)) ==
734 * We treat invalid cookies in the same was as no cookie as
737 next = LISTEN_SEND_VERIFY_REQUEST;
739 /* Cookie verification succeeded */
740 next = LISTEN_SUCCESS;
744 if (next == LISTEN_SEND_VERIFY_REQUEST) {
746 * There was no cookie in the ClientHello so we need to send a
747 * HelloVerifyRequest. If this fails we do not worry about trying
748 * to resend, we just drop it.
752 * Dump the read packet, we don't need it any more. Ignore return
755 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL);
756 BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
757 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);
759 /* Generate the cookie */
760 if (s->ctx->app_gen_cookie_cb == NULL ||
761 s->ctx->app_gen_cookie_cb(s, cookie, &cookielen) == 0 ||
763 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
768 p = &buf[DTLS1_RT_HEADER_LENGTH];
769 msglen = dtls_raw_hello_verify_request(p + DTLS1_HM_HEADER_LENGTH,
772 *p++ = DTLS1_MT_HELLO_VERIFY_REQUEST;
777 /* Message sequence number is always 0 for a HelloVerifyRequest */
781 * We never fragment a HelloVerifyRequest, so fragment offset is 0
782 * and fragment length is message length
787 /* Set reclen equal to length of whole handshake message */
788 reclen = msglen + DTLS1_HM_HEADER_LENGTH;
790 /* Add the record header */
793 *(p++) = SSL3_RT_HANDSHAKE;
795 * Special case: for hello verify request, client version 1.0 and we
796 * haven't decided which version to use yet send back using version
797 * 1.0 header: otherwise some clients will ignore it.
799 if (s->method->version == DTLS_ANY_VERSION) {
800 *(p++) = DTLS1_VERSION >> 8;
801 *(p++) = DTLS1_VERSION & 0xff;
803 *(p++) = s->version >> 8;
804 *(p++) = s->version & 0xff;
808 * Record sequence number is always the same as in the received
811 memcpy(p, seq, SEQ_NUM_SIZE);
818 * Set reclen equal to length of whole record including record
821 reclen += DTLS1_RT_HEADER_LENGTH;
824 s->msg_callback(1, 0, SSL3_RT_HEADER, buf,
825 DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
828 * This is unneccessary if rbio and wbio are one and the same - but
831 if(BIO_dgram_get_peer(rbio, &tmpclient) <= 0
832 || BIO_dgram_set_peer(wbio, &tmpclient) <= 0) {
833 SSLerr(SSL_F_DTLS1_LISTEN, ERR_R_INTERNAL_ERROR);
837 if (BIO_write(wbio, buf, reclen) < (int)reclen) {
838 if(BIO_should_retry(wbio)) {
840 * Non-blocking IO...but we're stateless, so we're just
841 * going to drop this packet.
848 if (BIO_flush(wbio) <= 0) {
849 if(BIO_should_retry(wbio)) {
851 * Non-blocking IO...but we're stateless, so we're just
852 * going to drop this packet.
859 } while (next != LISTEN_SUCCESS);
862 * Set expected sequence numbers to continue the handshake.
864 s->d1->handshake_read_seq = 1;
865 s->d1->handshake_write_seq = 1;
866 s->d1->next_handshake_write_seq = 1;
867 DTLS_RECORD_LAYER_set_write_sequence(&s->rlayer, seq);
870 * We are doing cookie exchange, so make sure we set that option in the
873 SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
875 /* Put us into the "init" state so that we don't get our state cleared */
876 statem_set_in_init(s, 1);
878 if(BIO_dgram_get_peer(rbio, client) <= 0) {
879 SSLerr(SSL_F_DTLS1_LISTEN, ERR_R_INTERNAL_ERROR);
886 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL);
888 /* Dump this packet. Ignore return value */
889 BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
894 static int dtls1_set_handshake_header(SSL *s, int htype, unsigned long len)
896 unsigned char *p = (unsigned char *)s->init_buf->data;
897 dtls1_set_message_header(s, p, htype, len, 0, len);
898 s->init_num = (int)len + DTLS1_HM_HEADER_LENGTH;
900 /* Buffer the message to handle re-xmits */
902 if (!dtls1_buffer_message(s, 0))
908 static int dtls1_handshake_write(SSL *s)
910 return dtls1_do_write(s, SSL3_RT_HANDSHAKE);
913 #ifndef OPENSSL_NO_HEARTBEATS
914 int dtls1_process_heartbeat(SSL *s, unsigned char *p, unsigned int length)
917 unsigned short hbtype;
918 unsigned int payload;
919 unsigned int padding = 16; /* Use minimum padding */
922 s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
923 p, length, s, s->msg_callback_arg);
925 /* Read type and payload length first */
926 if (1 + 2 + 16 > length)
927 return 0; /* silently discard */
928 if (length > SSL3_RT_MAX_PLAIN_LENGTH)
929 return 0; /* silently discard per RFC 6520 sec. 4 */
933 if (1 + 2 + payload + 16 > length)
934 return 0; /* silently discard per RFC 6520 sec. 4 */
937 if (hbtype == TLS1_HB_REQUEST) {
938 unsigned char *buffer, *bp;
939 unsigned int write_length = 1 /* heartbeat type */ +
940 2 /* heartbeat length */ +
944 if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
948 * Allocate memory for the response, size is 1 byte message type,
949 * plus 2 bytes payload length, plus payload, plus padding
951 buffer = OPENSSL_malloc(write_length);
956 /* Enter response type, length and copy payload */
957 *bp++ = TLS1_HB_RESPONSE;
959 memcpy(bp, pl, payload);
962 if (RAND_bytes(bp, padding) <= 0) {
963 OPENSSL_free(buffer);
967 r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
969 if (r >= 0 && s->msg_callback)
970 s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
971 buffer, write_length, s, s->msg_callback_arg);
973 OPENSSL_free(buffer);
977 } else if (hbtype == TLS1_HB_RESPONSE) {
981 * We only send sequence numbers (2 bytes unsigned int), and 16
982 * random bytes, so we just try to read the sequence number
986 if (payload == 18 && seq == s->tlsext_hb_seq) {
989 s->tlsext_hb_pending = 0;
996 int dtls1_heartbeat(SSL *s)
998 unsigned char *buf, *p;
1000 unsigned int payload = 18; /* Sequence number + random bytes */
1001 unsigned int padding = 16; /* Use minimum padding */
1003 /* Only send if peer supports and accepts HB requests... */
1004 if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
1005 s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS) {
1006 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
1010 /* ...and there is none in flight yet... */
1011 if (s->tlsext_hb_pending) {
1012 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PENDING);
1016 /* ...and no handshake in progress. */
1017 if (SSL_in_init(s) || s->in_handshake) {
1018 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_UNEXPECTED_MESSAGE);
1023 * Check if padding is too long, payload and padding must not exceed 2^14
1024 * - 3 = 16381 bytes in total.
1026 OPENSSL_assert(payload + padding <= 16381);
1029 * Create HeartBeat message, we just use a sequence number
1030 * as payload to distuingish different messages and add
1031 * some random stuff.
1032 * - Message Type, 1 byte
1033 * - Payload Length, 2 bytes (unsigned int)
1034 * - Payload, the sequence number (2 bytes uint)
1035 * - Payload, random bytes (16 bytes uint)
1038 buf = OPENSSL_malloc(1 + 2 + payload + padding);
1040 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_MALLOC_FAILURE);
1045 *p++ = TLS1_HB_REQUEST;
1046 /* Payload length (18 bytes here) */
1048 /* Sequence number */
1049 s2n(s->tlsext_hb_seq, p);
1050 /* 16 random bytes */
1051 if (RAND_bytes(p, 16) <= 0) {
1052 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR);
1056 /* Random padding */
1057 if (RAND_bytes(p, padding) <= 0) {
1058 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR);
1062 ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
1064 if (s->msg_callback)
1065 s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1066 buf, 3 + payload + padding,
1067 s, s->msg_callback_arg);
1069 dtls1_start_timer(s);
1070 s->tlsext_hb_pending = 1;
1080 int dtls1_shutdown(SSL *s)
1083 #ifndef OPENSSL_NO_SCTP
1086 wbio = SSL_get_wbio(s);
1087 if (wbio != NULL && BIO_dgram_is_sctp(wbio) &&
1088 !(s->shutdown & SSL_SENT_SHUTDOWN)) {
1089 ret = BIO_dgram_sctp_wait_for_dry(wbio);
1094 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1,
1098 ret = ssl3_shutdown(s);
1099 #ifndef OPENSSL_NO_SCTP
1100 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
1105 int dtls1_query_mtu(SSL *s)
1107 if (s->d1->link_mtu) {
1109 s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
1110 s->d1->link_mtu = 0;
1113 /* AHA! Figure out the MTU, and stick to the right size */
1114 if (s->d1->mtu < dtls1_min_mtu(s)) {
1115 if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
1117 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
1120 * I've seen the kernel return bogus numbers when it doesn't know
1121 * (initial write), so just make sure we have a reasonable number
1123 if (s->d1->mtu < dtls1_min_mtu(s)) {
1124 /* Set to min mtu */
1125 s->d1->mtu = dtls1_min_mtu(s);
1126 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
1135 unsigned int dtls1_link_min_mtu(void)
1137 return (g_probable_mtu[(sizeof(g_probable_mtu) /
1138 sizeof(g_probable_mtu[0])) - 1]);
1141 unsigned int dtls1_min_mtu(SSL *s)
1143 return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));