2 * DTLS implementation written by Nagendra Modadugu
3 * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
5 /* ====================================================================
6 * Copyright (c) 1999-2005 The OpenSSL Project. All rights reserved.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
20 * 3. All advertising materials mentioning features or use of this
21 * software must display the following acknowledgment:
22 * "This product includes software developed by the OpenSSL Project
23 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26 * endorse or promote products derived from this software without
27 * prior written permission. For written permission, please contact
28 * openssl-core@OpenSSL.org.
30 * 5. Products derived from this software may not be called "OpenSSL"
31 * nor may "OpenSSL" appear in their names without prior written
32 * permission of the OpenSSL Project.
34 * 6. Redistributions of any form whatsoever must retain the following
36 * "This product includes software developed by the OpenSSL Project
37 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
39 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50 * OF THE POSSIBILITY OF SUCH DAMAGE.
51 * ====================================================================
53 * This product includes cryptographic software written by Eric Young
54 * (eay@cryptsoft.com). This product includes software written by Tim
55 * Hudson (tjh@cryptsoft.com).
61 #include <openssl/objects.h>
62 #include <openssl/rand.h>
65 #if defined(OPENSSL_SYS_VMS)
66 # include <sys/timeb.h>
67 #elif defined(OPENSSL_SYS_NETWARE) && !defined(_WINSOCK2API_)
68 # include <sys/timeval.h>
69 #elif defined(OPENSSL_SYS_VXWORKS)
70 # include <sys/times.h>
71 #elif !defined(OPENSSL_SYS_WIN32)
72 # include <sys/time.h>
75 static void get_current_time(struct timeval *t);
76 static int dtls1_set_handshake_header(SSL *s, int type, unsigned long len);
77 static int dtls1_handshake_write(SSL *s);
78 int dtls1_listen(SSL *s, BIO_ADDR *client);
79 static unsigned int dtls1_link_min_mtu(void);
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,
92 TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
93 TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
95 tls1_export_keying_material,
96 SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV,
97 DTLS1_HM_HEADER_LENGTH,
98 dtls1_set_handshake_header,
102 const SSL3_ENC_METHOD DTLSv1_2_enc_data = {
105 tls1_setup_key_block,
106 tls1_generate_master_secret,
107 tls1_change_cipher_state,
108 tls1_final_finish_mac,
109 TLS1_FINISH_MAC_LENGTH,
110 TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
111 TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
113 tls1_export_keying_material,
114 SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV | SSL_ENC_FLAG_SIGALGS
115 | SSL_ENC_FLAG_SHA256_PRF | SSL_ENC_FLAG_TLS1_2_CIPHERS,
116 DTLS1_HM_HEADER_LENGTH,
117 dtls1_set_handshake_header,
118 dtls1_handshake_write
121 long dtls1_default_timeout(void)
124 * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for
125 * http, the cache would over fill
127 return (60 * 60 * 2);
130 int dtls1_new(SSL *s)
134 if (!DTLS_RECORD_LAYER_new(&s->rlayer)) {
140 if ((d1 = OPENSSL_zalloc(sizeof(*d1))) == NULL) {
145 d1->buffered_messages = pqueue_new();
146 d1->sent_messages = pqueue_new();
149 d1->cookie_len = sizeof(s->d1->cookie);
155 if (d1->buffered_messages == NULL || d1->sent_messages == NULL) {
156 pqueue_free(d1->buffered_messages);
157 pqueue_free(d1->sent_messages);
164 s->method->ssl_clear(s);
168 static void dtls1_clear_queues(SSL *s)
171 hm_fragment *frag = NULL;
173 while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) {
174 frag = (hm_fragment *)item->data;
175 dtls1_hm_fragment_free(frag);
179 while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) {
180 frag = (hm_fragment *)item->data;
181 dtls1_hm_fragment_free(frag);
186 void dtls1_free(SSL *s)
188 DTLS_RECORD_LAYER_free(&s->rlayer);
192 dtls1_clear_queues(s);
194 pqueue_free(s->d1->buffered_messages);
195 pqueue_free(s->d1->sent_messages);
201 void dtls1_clear(SSL *s)
203 pqueue *buffered_messages;
204 pqueue *sent_messages;
206 unsigned int link_mtu;
208 DTLS_RECORD_LAYER_clear(&s->rlayer);
211 buffered_messages = s->d1->buffered_messages;
212 sent_messages = s->d1->sent_messages;
214 link_mtu = s->d1->link_mtu;
216 dtls1_clear_queues(s);
218 memset(s->d1, 0, sizeof(*s->d1));
221 s->d1->cookie_len = sizeof(s->d1->cookie);
224 if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) {
226 s->d1->link_mtu = link_mtu;
229 s->d1->buffered_messages = buffered_messages;
230 s->d1->sent_messages = sent_messages;
234 if (s->options & SSL_OP_CISCO_ANYCONNECT)
235 s->client_version = s->version = DTLS1_BAD_VER;
236 else if (s->method->version == DTLS_ANY_VERSION)
237 s->version = DTLS_MAX_VERSION;
239 s->version = s->method->version;
242 long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
247 case DTLS_CTRL_GET_TIMEOUT:
248 if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) {
252 case DTLS_CTRL_HANDLE_TIMEOUT:
253 ret = dtls1_handle_timeout(s);
255 case DTLS_CTRL_LISTEN:
256 ret = dtls1_listen(s, parg);
258 case DTLS_CTRL_SET_LINK_MTU:
259 if (larg < (long)dtls1_link_min_mtu())
261 s->d1->link_mtu = larg;
263 case DTLS_CTRL_GET_LINK_MIN_MTU:
264 return (long)dtls1_link_min_mtu();
265 case SSL_CTRL_SET_MTU:
267 * We may not have a BIO set yet so can't call dtls1_min_mtu()
268 * We'll have to make do with dtls1_link_min_mtu() and max overhead
270 if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD)
275 ret = ssl3_ctrl(s, cmd, larg, parg);
282 * As it's impossible to use stream ciphers in "datagram" mode, this
283 * simple filter is designed to disengage them in DTLS. Unfortunately
284 * there is no universal way to identify stream SSL_CIPHER, so we have
285 * to explicitly list their SSL_* codes. Currently RC4 is the only one
286 * available, but if new ones emerge, they will have to be added...
288 const SSL_CIPHER *dtls1_get_cipher(unsigned int u)
290 const SSL_CIPHER *ciph = ssl3_get_cipher(u);
293 if (ciph->algorithm_enc == SSL_RC4)
300 void dtls1_start_timer(SSL *s)
302 #ifndef OPENSSL_NO_SCTP
303 /* Disable timer for SCTP */
304 if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
305 memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
310 /* If timer is not set, initialize duration with 1 second */
311 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
312 s->d1->timeout_duration = 1;
315 /* Set timeout to current time */
316 get_current_time(&(s->d1->next_timeout));
318 /* Add duration to current time */
319 s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
320 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
321 &(s->d1->next_timeout));
324 struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft)
326 struct timeval timenow;
328 /* If no timeout is set, just return NULL */
329 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
333 /* Get current time */
334 get_current_time(&timenow);
336 /* If timer already expired, set remaining time to 0 */
337 if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
338 (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
339 s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
340 memset(timeleft, 0, sizeof(*timeleft));
344 /* Calculate time left until timer expires */
345 memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
346 timeleft->tv_sec -= timenow.tv_sec;
347 timeleft->tv_usec -= timenow.tv_usec;
348 if (timeleft->tv_usec < 0) {
350 timeleft->tv_usec += 1000000;
354 * If remaining time is less than 15 ms, set it to 0 to prevent issues
355 * because of small devergences with socket timeouts.
357 if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
358 memset(timeleft, 0, sizeof(*timeleft));
364 int dtls1_is_timer_expired(SSL *s)
366 struct timeval timeleft;
368 /* Get time left until timeout, return false if no timer running */
369 if (dtls1_get_timeout(s, &timeleft) == NULL) {
373 /* Return false if timer is not expired yet */
374 if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
378 /* Timer expired, so return true */
382 void dtls1_double_timeout(SSL *s)
384 s->d1->timeout_duration *= 2;
385 if (s->d1->timeout_duration > 60)
386 s->d1->timeout_duration = 60;
387 dtls1_start_timer(s);
390 void dtls1_stop_timer(SSL *s)
392 /* Reset everything */
393 memset(&s->d1->timeout, 0, sizeof(s->d1->timeout));
394 memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
395 s->d1->timeout_duration = 1;
396 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
397 &(s->d1->next_timeout));
398 /* Clear retransmission buffer */
399 dtls1_clear_record_buffer(s);
402 int dtls1_check_timeout_num(SSL *s)
406 s->d1->timeout.num_alerts++;
408 /* Reduce MTU after 2 unsuccessful retransmissions */
409 if (s->d1->timeout.num_alerts > 2
410 && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
412 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0,
414 if (mtu < s->d1->mtu)
418 if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) {
419 /* fail the connection, enough alerts have been sent */
420 SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM, SSL_R_READ_TIMEOUT_EXPIRED);
427 int dtls1_handle_timeout(SSL *s)
429 /* if no timer is expired, don't do anything */
430 if (!dtls1_is_timer_expired(s)) {
434 dtls1_double_timeout(s);
436 if (dtls1_check_timeout_num(s) < 0)
439 s->d1->timeout.read_timeouts++;
440 if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) {
441 s->d1->timeout.read_timeouts = 1;
443 #ifndef OPENSSL_NO_HEARTBEATS
444 if (s->tlsext_hb_pending) {
445 s->tlsext_hb_pending = 0;
446 return dtls1_heartbeat(s);
450 dtls1_start_timer(s);
451 return dtls1_retransmit_buffered_messages(s);
454 static void get_current_time(struct timeval *t)
464 SystemTimeToFileTime(&st, &now.ft);
466 now.ul -= 116444736000000000ULL;
468 now.ul -= 116444736000000000UI64; /* re-bias to 1/1/1970 */
470 t->tv_sec = (long)(now.ul / 10000000);
471 t->tv_usec = ((int)(now.ul % 10000000)) / 10;
472 #elif defined(OPENSSL_SYS_VMS)
475 t->tv_sec = (long)tb.time;
476 t->tv_usec = (long)tb.millitm * 1000;
478 gettimeofday(t, NULL);
483 #define LISTEN_SUCCESS 2
484 #define LISTEN_SEND_VERIFY_REQUEST 1
487 int dtls1_listen(SSL *s, BIO_ADDR *client)
489 int next, n, ret = 0, clearpkt = 0;
490 unsigned char cookie[DTLS1_COOKIE_LENGTH];
491 unsigned char seq[SEQ_NUM_SIZE];
492 const unsigned char *data;
493 unsigned char *p, *buf;
494 unsigned long reclen, fragoff, fraglen, msglen;
495 unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen;
498 BIO_ADDR *tmpclient = NULL;
499 PACKET pkt, msgpkt, msgpayload, session, cookiepkt;
501 /* Ensure there is no state left over from a previous invocation */
507 rbio = SSL_get_rbio(s);
508 wbio = SSL_get_wbio(s);
511 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_BIO_NOT_SET);
516 * We only peek at incoming ClientHello's until we're sure we are going to
517 * to respond with a HelloVerifyRequest. If its a ClientHello with a valid
518 * cookie then we leave it in the BIO for accept to handle.
520 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);
523 * Note: This check deliberately excludes DTLS1_BAD_VER because that version
524 * requires the MAC to be calculated *including* the first ClientHello
525 * (without the cookie). Since DTLSv1_listen is stateless that cannot be
526 * supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via
529 if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
530 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_UNSUPPORTED_SSL_VERSION);
534 if (s->init_buf == NULL) {
535 if ((bufm = BUF_MEM_new()) == NULL) {
536 SSLerr(SSL_F_DTLS1_LISTEN, ERR_R_MALLOC_FAILURE);
540 if (!BUF_MEM_grow(bufm, SSL3_RT_MAX_PLAIN_LENGTH)) {
542 SSLerr(SSL_F_DTLS1_LISTEN, ERR_R_MALLOC_FAILURE);
547 buf = (unsigned char *)s->init_buf->data;
554 * Technically a ClientHello could be SSL3_RT_MAX_PLAIN_LENGTH
555 * + DTLS1_RT_HEADER_LENGTH bytes long. Normally init_buf does not store
556 * the record header as well, but we do here. We've set up init_buf to
557 * be the standard size for simplicity. In practice we shouldn't ever
558 * receive a ClientHello as long as this. If we do it will get dropped
559 * in the record length check below.
561 n = BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
564 if(BIO_should_retry(rbio)) {
565 /* Non-blocking IO */
571 /* If we hit any problems we need to clear this packet from the BIO */
574 if (!PACKET_buf_init(&pkt, buf, n)) {
575 SSLerr(SSL_F_DTLS1_LISTEN, ERR_R_INTERNAL_ERROR);
580 * Parse the received record. If there are any problems with it we just
581 * dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is
582 * resilient in the face of invalid records (e.g., invalid formatting,
583 * length, MAC, etc.). In general, invalid records SHOULD be silently
584 * discarded, thus preserving the association; however, an error MAY be
585 * logged for diagnostic purposes."
588 /* this packet contained a partial record, dump it */
589 if (n < DTLS1_RT_HEADER_LENGTH) {
590 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_RECORD_TOO_SMALL);
595 s->msg_callback(0, 0, SSL3_RT_HEADER, buf,
596 DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
598 /* Get the record header */
599 if (!PACKET_get_1(&pkt, &rectype)
600 || !PACKET_get_1(&pkt, &versmajor)) {
601 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_LENGTH_MISMATCH);
605 if (rectype != SSL3_RT_HANDSHAKE) {
606 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
611 * Check record version number. We only check that the major version is
614 if (versmajor != DTLS1_VERSION_MAJOR) {
615 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
619 if (!PACKET_forward(&pkt, 1)
620 /* Save the sequence number: 64 bits, with top 2 bytes = epoch */
621 || !PACKET_copy_bytes(&pkt, seq, SEQ_NUM_SIZE)
622 || !PACKET_get_length_prefixed_2(&pkt, &msgpkt)
623 || PACKET_remaining(&pkt) != 0) {
624 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_LENGTH_MISMATCH);
628 /* This is an initial ClientHello so the epoch has to be 0 */
629 if (seq[0] != 0 || seq[1] != 0) {
630 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
634 /* Get a pointer to the raw message for the later callback */
635 data = PACKET_data(&msgpkt);
637 /* Finished processing the record header, now process the message */
638 if (!PACKET_get_1(&msgpkt, &msgtype)
639 || !PACKET_get_net_3(&msgpkt, &msglen)
640 || !PACKET_get_net_2(&msgpkt, &msgseq)
641 || !PACKET_get_net_3(&msgpkt, &fragoff)
642 || !PACKET_get_net_3(&msgpkt, &fraglen)
643 || !PACKET_get_sub_packet(&msgpkt, &msgpayload, msglen)
644 || PACKET_remaining(&msgpkt) != 0) {
645 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_LENGTH_MISMATCH);
649 if (msgtype != SSL3_MT_CLIENT_HELLO) {
650 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
654 /* Message sequence number can only be 0 or 1 */
656 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_INVALID_SEQUENCE_NUMBER);
660 /* We don't support a fragmented ClientHello whilst listening */
661 if (fragoff != 0 || fraglen != msglen) {
662 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_FRAGMENTED_CLIENT_HELLO);
667 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, data,
668 msglen + DTLS1_HM_HEADER_LENGTH, s,
669 s->msg_callback_arg);
671 if (!PACKET_get_net_2(&msgpayload, &clientvers)) {
672 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_LENGTH_MISMATCH);
677 * Verify client version is supported
679 if (DTLS_VERSION_LT(clientvers, (unsigned int)s->method->version) &&
680 s->method->version != DTLS_ANY_VERSION) {
681 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_WRONG_VERSION_NUMBER);
685 if (!PACKET_forward(&msgpayload, SSL3_RANDOM_SIZE)
686 || !PACKET_get_length_prefixed_1(&msgpayload, &session)
687 || !PACKET_get_length_prefixed_1(&msgpayload, &cookiepkt)) {
688 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_LENGTH_MISMATCH);
693 * Check if we have a cookie or not. If not we need to send a
694 * HelloVerifyRequest.
696 if (PACKET_remaining(&cookiepkt) == 0) {
697 next = LISTEN_SEND_VERIFY_REQUEST;
700 * We have a cookie, so lets check it.
702 if (s->ctx->app_verify_cookie_cb == NULL) {
703 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_NO_VERIFY_COOKIE_CALLBACK);
707 if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&cookiepkt),
708 PACKET_remaining(&cookiepkt)) ==
711 * We treat invalid cookies in the same was as no cookie as
714 next = LISTEN_SEND_VERIFY_REQUEST;
716 /* Cookie verification succeeded */
717 next = LISTEN_SUCCESS;
721 if (next == LISTEN_SEND_VERIFY_REQUEST) {
723 * There was no cookie in the ClientHello so we need to send a
724 * HelloVerifyRequest. If this fails we do not worry about trying
725 * to resend, we just drop it.
729 * Dump the read packet, we don't need it any more. Ignore return
732 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL);
733 BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
734 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);
736 /* Generate the cookie */
737 if (s->ctx->app_gen_cookie_cb == NULL ||
738 s->ctx->app_gen_cookie_cb(s, cookie, &cookielen) == 0 ||
740 SSLerr(SSL_F_DTLS1_LISTEN, SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
745 p = &buf[DTLS1_RT_HEADER_LENGTH];
746 msglen = dtls_raw_hello_verify_request(p + DTLS1_HM_HEADER_LENGTH,
749 *p++ = DTLS1_MT_HELLO_VERIFY_REQUEST;
754 /* Message sequence number is always 0 for a HelloVerifyRequest */
758 * We never fragment a HelloVerifyRequest, so fragment offset is 0
759 * and fragment length is message length
764 /* Set reclen equal to length of whole handshake message */
765 reclen = msglen + DTLS1_HM_HEADER_LENGTH;
767 /* Add the record header */
770 *(p++) = SSL3_RT_HANDSHAKE;
772 * Special case: for hello verify request, client version 1.0 and we
773 * haven't decided which version to use yet send back using version
774 * 1.0 header: otherwise some clients will ignore it.
776 if (s->method->version == DTLS_ANY_VERSION) {
777 *(p++) = DTLS1_VERSION >> 8;
778 *(p++) = DTLS1_VERSION & 0xff;
780 *(p++) = s->version >> 8;
781 *(p++) = s->version & 0xff;
785 * Record sequence number is always the same as in the received
788 memcpy(p, seq, SEQ_NUM_SIZE);
795 * Set reclen equal to length of whole record including record
798 reclen += DTLS1_RT_HEADER_LENGTH;
801 s->msg_callback(1, 0, SSL3_RT_HEADER, buf,
802 DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
805 * This is unneccessary if rbio and wbio are one and the same - but
808 if ((tmpclient = BIO_ADDR_new()) == NULL
809 || BIO_dgram_get_peer(rbio, tmpclient) <= 0
810 || BIO_dgram_set_peer(wbio, tmpclient) <= 0) {
811 SSLerr(SSL_F_DTLS1_LISTEN, ERR_R_INTERNAL_ERROR);
814 BIO_ADDR_free(tmpclient);
817 if (BIO_write(wbio, buf, reclen) < (int)reclen) {
818 if(BIO_should_retry(wbio)) {
820 * Non-blocking IO...but we're stateless, so we're just
821 * going to drop this packet.
828 if (BIO_flush(wbio) <= 0) {
829 if(BIO_should_retry(wbio)) {
831 * Non-blocking IO...but we're stateless, so we're just
832 * going to drop this packet.
839 } while (next != LISTEN_SUCCESS);
842 * Set expected sequence numbers to continue the handshake.
844 s->d1->handshake_read_seq = 1;
845 s->d1->handshake_write_seq = 1;
846 s->d1->next_handshake_write_seq = 1;
847 DTLS_RECORD_LAYER_set_write_sequence(&s->rlayer, seq);
850 * We are doing cookie exchange, so make sure we set that option in the
853 SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
856 * Tell the state machine that we've done the initial hello verify
859 ossl_statem_set_hello_verify_done(s);
861 if(BIO_dgram_get_peer(rbio, client) <= 0) {
862 SSLerr(SSL_F_DTLS1_LISTEN, ERR_R_INTERNAL_ERROR);
869 BIO_ADDR_free(tmpclient);
870 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL);
872 /* Dump this packet. Ignore return value */
873 BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
878 static int dtls1_set_handshake_header(SSL *s, int htype, unsigned long len)
880 unsigned char *p = (unsigned char *)s->init_buf->data;
881 dtls1_set_message_header(s, p, htype, len, 0, len);
882 s->init_num = (int)len + DTLS1_HM_HEADER_LENGTH;
884 /* Buffer the message to handle re-xmits */
886 if (!dtls1_buffer_message(s, 0))
892 static int dtls1_handshake_write(SSL *s)
894 return dtls1_do_write(s, SSL3_RT_HANDSHAKE);
897 #ifndef OPENSSL_NO_HEARTBEATS
898 int dtls1_process_heartbeat(SSL *s, unsigned char *p, unsigned int length)
901 unsigned short hbtype;
902 unsigned int payload;
903 unsigned int padding = 16; /* Use minimum padding */
906 s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
907 p, length, s, s->msg_callback_arg);
909 /* Read type and payload length first */
910 if (1 + 2 + 16 > length)
911 return 0; /* silently discard */
912 if (length > SSL3_RT_MAX_PLAIN_LENGTH)
913 return 0; /* silently discard per RFC 6520 sec. 4 */
917 if (1 + 2 + payload + 16 > length)
918 return 0; /* silently discard per RFC 6520 sec. 4 */
921 if (hbtype == TLS1_HB_REQUEST) {
922 unsigned char *buffer, *bp;
923 unsigned int write_length = 1 /* heartbeat type */ +
924 2 /* heartbeat length */ +
928 if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
932 * Allocate memory for the response, size is 1 byte message type,
933 * plus 2 bytes payload length, plus payload, plus padding
935 buffer = OPENSSL_malloc(write_length);
940 /* Enter response type, length and copy payload */
941 *bp++ = TLS1_HB_RESPONSE;
943 memcpy(bp, pl, payload);
946 if (RAND_bytes(bp, padding) <= 0) {
947 OPENSSL_free(buffer);
951 r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
953 if (r >= 0 && s->msg_callback)
954 s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
955 buffer, write_length, s, s->msg_callback_arg);
957 OPENSSL_free(buffer);
961 } else if (hbtype == TLS1_HB_RESPONSE) {
965 * We only send sequence numbers (2 bytes unsigned int), and 16
966 * random bytes, so we just try to read the sequence number
970 if (payload == 18 && seq == s->tlsext_hb_seq) {
973 s->tlsext_hb_pending = 0;
980 int dtls1_heartbeat(SSL *s)
982 unsigned char *buf, *p;
984 unsigned int payload = 18; /* Sequence number + random bytes */
985 unsigned int padding = 16; /* Use minimum padding */
987 /* Only send if peer supports and accepts HB requests... */
988 if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
989 s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS) {
990 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
994 /* ...and there is none in flight yet... */
995 if (s->tlsext_hb_pending) {
996 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PENDING);
1000 /* ...and no handshake in progress. */
1001 if (SSL_in_init(s) || ossl_statem_get_in_handshake(s)) {
1002 SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_UNEXPECTED_MESSAGE);
1007 * Create HeartBeat message, we just use a sequence number
1008 * as payload to distuingish different messages and add
1009 * some random stuff.
1010 * - Message Type, 1 byte
1011 * - Payload Length, 2 bytes (unsigned int)
1012 * - Payload, the sequence number (2 bytes uint)
1013 * - Payload, random bytes (16 bytes uint)
1016 buf = OPENSSL_malloc(1 + 2 + payload + padding);
1018 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_MALLOC_FAILURE);
1023 *p++ = TLS1_HB_REQUEST;
1024 /* Payload length (18 bytes here) */
1026 /* Sequence number */
1027 s2n(s->tlsext_hb_seq, p);
1028 /* 16 random bytes */
1029 if (RAND_bytes(p, 16) <= 0) {
1030 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR);
1034 /* Random padding */
1035 if (RAND_bytes(p, padding) <= 0) {
1036 SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR);
1040 ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
1042 if (s->msg_callback)
1043 s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1044 buf, 3 + payload + padding,
1045 s, s->msg_callback_arg);
1047 dtls1_start_timer(s);
1048 s->tlsext_hb_pending = 1;
1058 int dtls1_shutdown(SSL *s)
1061 #ifndef OPENSSL_NO_SCTP
1064 wbio = SSL_get_wbio(s);
1065 if (wbio != NULL && BIO_dgram_is_sctp(wbio) &&
1066 !(s->shutdown & SSL_SENT_SHUTDOWN)) {
1067 ret = BIO_dgram_sctp_wait_for_dry(wbio);
1072 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1,
1076 ret = ssl3_shutdown(s);
1077 #ifndef OPENSSL_NO_SCTP
1078 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
1083 int dtls1_query_mtu(SSL *s)
1085 if (s->d1->link_mtu) {
1087 s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
1088 s->d1->link_mtu = 0;
1091 /* AHA! Figure out the MTU, and stick to the right size */
1092 if (s->d1->mtu < dtls1_min_mtu(s)) {
1093 if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
1095 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
1098 * I've seen the kernel return bogus numbers when it doesn't know
1099 * (initial write), so just make sure we have a reasonable number
1101 if (s->d1->mtu < dtls1_min_mtu(s)) {
1102 /* Set to min mtu */
1103 s->d1->mtu = dtls1_min_mtu(s);
1104 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
1113 static unsigned int dtls1_link_min_mtu(void)
1115 return (g_probable_mtu[(sizeof(g_probable_mtu) /
1116 sizeof(g_probable_mtu[0])) - 1]);
1119 unsigned int dtls1_min_mtu(SSL *s)
1121 return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));