2 * Copyright 2005-2016 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
12 #include <openssl/objects.h>
13 #include <openssl/rand.h>
16 #if defined(OPENSSL_SYS_VMS)
17 # include <sys/timeb.h>
18 #elif defined(OPENSSL_SYS_VXWORKS)
19 # include <sys/times.h>
20 #elif !defined(OPENSSL_SYS_WIN32)
21 # include <sys/time.h>
24 static void get_current_time(struct timeval
*t
);
25 static int dtls1_handshake_write(SSL
*s
);
26 static size_t dtls1_link_min_mtu(void);
28 /* XDTLS: figure out the right values */
29 static const size_t g_probable_mtu
[] = { 1500, 512, 256 };
31 const SSL3_ENC_METHOD DTLSv1_enc_data
= {
35 tls1_generate_master_secret
,
36 tls1_change_cipher_state
,
37 tls1_final_finish_mac
,
38 TLS_MD_CLIENT_FINISH_CONST
, TLS_MD_CLIENT_FINISH_CONST_SIZE
,
39 TLS_MD_SERVER_FINISH_CONST
, TLS_MD_SERVER_FINISH_CONST_SIZE
,
41 tls1_export_keying_material
,
42 SSL_ENC_FLAG_DTLS
| SSL_ENC_FLAG_EXPLICIT_IV
,
43 dtls1_set_handshake_header
,
44 dtls1_close_construct_packet
,
48 const SSL3_ENC_METHOD DTLSv1_2_enc_data
= {
52 tls1_generate_master_secret
,
53 tls1_change_cipher_state
,
54 tls1_final_finish_mac
,
55 TLS_MD_CLIENT_FINISH_CONST
, TLS_MD_CLIENT_FINISH_CONST_SIZE
,
56 TLS_MD_SERVER_FINISH_CONST
, TLS_MD_SERVER_FINISH_CONST_SIZE
,
58 tls1_export_keying_material
,
59 SSL_ENC_FLAG_DTLS
| SSL_ENC_FLAG_EXPLICIT_IV
| SSL_ENC_FLAG_SIGALGS
60 | SSL_ENC_FLAG_SHA256_PRF
| SSL_ENC_FLAG_TLS1_2_CIPHERS
,
61 dtls1_set_handshake_header
,
62 dtls1_close_construct_packet
,
66 long dtls1_default_timeout(void)
69 * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for
70 * http, the cache would over fill
79 if (!DTLS_RECORD_LAYER_new(&s
->rlayer
)) {
85 if ((d1
= OPENSSL_zalloc(sizeof(*d1
))) == NULL
) {
90 d1
->buffered_messages
= pqueue_new();
91 d1
->sent_messages
= pqueue_new();
94 d1
->cookie_len
= sizeof(s
->d1
->cookie
);
100 if (d1
->buffered_messages
== NULL
|| d1
->sent_messages
== NULL
) {
101 pqueue_free(d1
->buffered_messages
);
102 pqueue_free(d1
->sent_messages
);
109 s
->method
->ssl_clear(s
);
113 static void dtls1_clear_queues(SSL
*s
)
115 dtls1_clear_received_buffer(s
);
116 dtls1_clear_sent_buffer(s
);
119 void dtls1_clear_received_buffer(SSL
*s
)
122 hm_fragment
*frag
= NULL
;
124 while ((item
= pqueue_pop(s
->d1
->buffered_messages
)) != NULL
) {
125 frag
= (hm_fragment
*)item
->data
;
126 dtls1_hm_fragment_free(frag
);
131 void dtls1_clear_sent_buffer(SSL
*s
)
134 hm_fragment
*frag
= NULL
;
136 while ((item
= pqueue_pop(s
->d1
->sent_messages
)) != NULL
) {
137 frag
= (hm_fragment
*)item
->data
;
138 dtls1_hm_fragment_free(frag
);
144 void dtls1_free(SSL
*s
)
146 DTLS_RECORD_LAYER_free(&s
->rlayer
);
150 dtls1_clear_queues(s
);
152 pqueue_free(s
->d1
->buffered_messages
);
153 pqueue_free(s
->d1
->sent_messages
);
159 void dtls1_clear(SSL
*s
)
161 pqueue
*buffered_messages
;
162 pqueue
*sent_messages
;
166 DTLS_RECORD_LAYER_clear(&s
->rlayer
);
169 buffered_messages
= s
->d1
->buffered_messages
;
170 sent_messages
= s
->d1
->sent_messages
;
172 link_mtu
= s
->d1
->link_mtu
;
174 dtls1_clear_queues(s
);
176 memset(s
->d1
, 0, sizeof(*s
->d1
));
179 s
->d1
->cookie_len
= sizeof(s
->d1
->cookie
);
182 if (SSL_get_options(s
) & SSL_OP_NO_QUERY_MTU
) {
184 s
->d1
->link_mtu
= link_mtu
;
187 s
->d1
->buffered_messages
= buffered_messages
;
188 s
->d1
->sent_messages
= sent_messages
;
193 if (s
->method
->version
== DTLS_ANY_VERSION
)
194 s
->version
= DTLS_MAX_VERSION
;
195 #ifndef OPENSSL_NO_DTLS1_METHOD
196 else if (s
->options
& SSL_OP_CISCO_ANYCONNECT
)
197 s
->client_version
= s
->version
= DTLS1_BAD_VER
;
200 s
->version
= s
->method
->version
;
203 long dtls1_ctrl(SSL
*s
, int cmd
, long larg
, void *parg
)
208 case DTLS_CTRL_GET_TIMEOUT
:
209 if (dtls1_get_timeout(s
, (struct timeval
*)parg
) != NULL
) {
213 case DTLS_CTRL_HANDLE_TIMEOUT
:
214 ret
= dtls1_handle_timeout(s
);
216 case DTLS_CTRL_SET_LINK_MTU
:
217 if (larg
< (long)dtls1_link_min_mtu())
219 s
->d1
->link_mtu
= larg
;
221 case DTLS_CTRL_GET_LINK_MIN_MTU
:
222 return (long)dtls1_link_min_mtu();
223 case SSL_CTRL_SET_MTU
:
225 * We may not have a BIO set yet so can't call dtls1_min_mtu()
226 * We'll have to make do with dtls1_link_min_mtu() and max overhead
228 if (larg
< (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD
)
233 ret
= ssl3_ctrl(s
, cmd
, larg
, parg
);
239 void dtls1_start_timer(SSL
*s
)
241 #ifndef OPENSSL_NO_SCTP
242 /* Disable timer for SCTP */
243 if (BIO_dgram_is_sctp(SSL_get_wbio(s
))) {
244 memset(&s
->d1
->next_timeout
, 0, sizeof(s
->d1
->next_timeout
));
249 /* If timer is not set, initialize duration with 1 second */
250 if (s
->d1
->next_timeout
.tv_sec
== 0 && s
->d1
->next_timeout
.tv_usec
== 0) {
251 s
->d1
->timeout_duration
= 1;
254 /* Set timeout to current time */
255 get_current_time(&(s
->d1
->next_timeout
));
257 /* Add duration to current time */
258 s
->d1
->next_timeout
.tv_sec
+= s
->d1
->timeout_duration
;
259 BIO_ctrl(SSL_get_rbio(s
), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT
, 0,
260 &(s
->d1
->next_timeout
));
263 struct timeval
*dtls1_get_timeout(SSL
*s
, struct timeval
*timeleft
)
265 struct timeval timenow
;
267 /* If no timeout is set, just return NULL */
268 if (s
->d1
->next_timeout
.tv_sec
== 0 && s
->d1
->next_timeout
.tv_usec
== 0) {
272 /* Get current time */
273 get_current_time(&timenow
);
275 /* If timer already expired, set remaining time to 0 */
276 if (s
->d1
->next_timeout
.tv_sec
< timenow
.tv_sec
||
277 (s
->d1
->next_timeout
.tv_sec
== timenow
.tv_sec
&&
278 s
->d1
->next_timeout
.tv_usec
<= timenow
.tv_usec
)) {
279 memset(timeleft
, 0, sizeof(*timeleft
));
283 /* Calculate time left until timer expires */
284 memcpy(timeleft
, &(s
->d1
->next_timeout
), sizeof(struct timeval
));
285 timeleft
->tv_sec
-= timenow
.tv_sec
;
286 timeleft
->tv_usec
-= timenow
.tv_usec
;
287 if (timeleft
->tv_usec
< 0) {
289 timeleft
->tv_usec
+= 1000000;
293 * If remaining time is less than 15 ms, set it to 0 to prevent issues
294 * because of small divergences with socket timeouts.
296 if (timeleft
->tv_sec
== 0 && timeleft
->tv_usec
< 15000) {
297 memset(timeleft
, 0, sizeof(*timeleft
));
303 int dtls1_is_timer_expired(SSL
*s
)
305 struct timeval timeleft
;
307 /* Get time left until timeout, return false if no timer running */
308 if (dtls1_get_timeout(s
, &timeleft
) == NULL
) {
312 /* Return false if timer is not expired yet */
313 if (timeleft
.tv_sec
> 0 || timeleft
.tv_usec
> 0) {
317 /* Timer expired, so return true */
321 void dtls1_double_timeout(SSL
*s
)
323 s
->d1
->timeout_duration
*= 2;
324 if (s
->d1
->timeout_duration
> 60)
325 s
->d1
->timeout_duration
= 60;
326 dtls1_start_timer(s
);
329 void dtls1_stop_timer(SSL
*s
)
331 /* Reset everything */
332 memset(&s
->d1
->timeout
, 0, sizeof(s
->d1
->timeout
));
333 memset(&s
->d1
->next_timeout
, 0, sizeof(s
->d1
->next_timeout
));
334 s
->d1
->timeout_duration
= 1;
335 BIO_ctrl(SSL_get_rbio(s
), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT
, 0,
336 &(s
->d1
->next_timeout
));
337 /* Clear retransmission buffer */
338 dtls1_clear_sent_buffer(s
);
341 int dtls1_check_timeout_num(SSL
*s
)
345 s
->d1
->timeout
.num_alerts
++;
347 /* Reduce MTU after 2 unsuccessful retransmissions */
348 if (s
->d1
->timeout
.num_alerts
> 2
349 && !(SSL_get_options(s
) & SSL_OP_NO_QUERY_MTU
)) {
351 BIO_ctrl(SSL_get_wbio(s
), BIO_CTRL_DGRAM_GET_FALLBACK_MTU
, 0, NULL
);
352 if (mtu
< s
->d1
->mtu
)
356 if (s
->d1
->timeout
.num_alerts
> DTLS1_TMO_ALERT_COUNT
) {
357 /* fail the connection, enough alerts have been sent */
358 SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM
, SSL_R_READ_TIMEOUT_EXPIRED
);
365 int dtls1_handle_timeout(SSL
*s
)
367 /* if no timer is expired, don't do anything */
368 if (!dtls1_is_timer_expired(s
)) {
372 dtls1_double_timeout(s
);
374 if (dtls1_check_timeout_num(s
) < 0)
377 s
->d1
->timeout
.read_timeouts
++;
378 if (s
->d1
->timeout
.read_timeouts
> DTLS1_TMO_READ_COUNT
) {
379 s
->d1
->timeout
.read_timeouts
= 1;
382 dtls1_start_timer(s
);
383 return dtls1_retransmit_buffered_messages(s
);
386 static void get_current_time(struct timeval
*t
)
396 SystemTimeToFileTime(&st
, &now
.ft
);
397 /* re-bias to 1/1/1970 */
399 now
.ul
-= 116444736000000000ULL;
402 now
.ul
-= 116444736000000000UI
64;
405 t
->tv_sec
= (long)(now
.ul
/ 10000000);
406 t
->tv_usec
= ((int)(now
.ul
% 10000000)) / 10;
407 #elif defined(OPENSSL_SYS_VMS)
410 t
->tv_sec
= (long)tb
.time
;
411 t
->tv_usec
= (long)tb
.millitm
* 1000;
413 gettimeofday(t
, NULL
);
417 #define LISTEN_SUCCESS 2
418 #define LISTEN_SEND_VERIFY_REQUEST 1
420 #ifndef OPENSSL_NO_SOCK
421 int DTLSv1_listen(SSL
*s
, BIO_ADDR
*client
)
423 int next
, n
, ret
= 0, clearpkt
= 0;
424 unsigned char cookie
[DTLS1_COOKIE_LENGTH
];
425 unsigned char seq
[SEQ_NUM_SIZE
];
426 const unsigned char *data
;
428 size_t fragoff
, fraglen
, msglen
;
429 unsigned int rectype
, versmajor
, msgseq
, msgtype
, clientvers
, cookielen
;
432 BIO_ADDR
*tmpclient
= NULL
;
433 PACKET pkt
, msgpkt
, msgpayload
, session
, cookiepkt
;
435 if (s
->handshake_func
== NULL
) {
436 /* Not properly initialized yet */
437 SSL_set_accept_state(s
);
440 /* Ensure there is no state left over from a previous invocation */
446 rbio
= SSL_get_rbio(s
);
447 wbio
= SSL_get_wbio(s
);
449 if (!rbio
|| !wbio
) {
450 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_BIO_NOT_SET
);
455 * We only peek at incoming ClientHello's until we're sure we are going to
456 * to respond with a HelloVerifyRequest. If its a ClientHello with a valid
457 * cookie then we leave it in the BIO for accept to handle.
459 BIO_ctrl(SSL_get_rbio(s
), BIO_CTRL_DGRAM_SET_PEEK_MODE
, 1, NULL
);
462 * Note: This check deliberately excludes DTLS1_BAD_VER because that version
463 * requires the MAC to be calculated *including* the first ClientHello
464 * (without the cookie). Since DTLSv1_listen is stateless that cannot be
465 * supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via
468 if ((s
->version
& 0xff00) != (DTLS1_VERSION
& 0xff00)) {
469 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_UNSUPPORTED_SSL_VERSION
);
473 if (s
->init_buf
== NULL
) {
474 if ((bufm
= BUF_MEM_new()) == NULL
) {
475 SSLerr(SSL_F_DTLSV1_LISTEN
, ERR_R_MALLOC_FAILURE
);
479 if (!BUF_MEM_grow(bufm
, SSL3_RT_MAX_PLAIN_LENGTH
)) {
481 SSLerr(SSL_F_DTLSV1_LISTEN
, ERR_R_MALLOC_FAILURE
);
486 buf
= (unsigned char *)s
->init_buf
->data
;
493 * Technically a ClientHello could be SSL3_RT_MAX_PLAIN_LENGTH
494 * + DTLS1_RT_HEADER_LENGTH bytes long. Normally init_buf does not store
495 * the record header as well, but we do here. We've set up init_buf to
496 * be the standard size for simplicity. In practice we shouldn't ever
497 * receive a ClientHello as long as this. If we do it will get dropped
498 * in the record length check below.
500 n
= BIO_read(rbio
, buf
, SSL3_RT_MAX_PLAIN_LENGTH
);
503 if (BIO_should_retry(rbio
)) {
504 /* Non-blocking IO */
510 /* If we hit any problems we need to clear this packet from the BIO */
513 if (!PACKET_buf_init(&pkt
, buf
, n
)) {
514 SSLerr(SSL_F_DTLSV1_LISTEN
, ERR_R_INTERNAL_ERROR
);
519 * Parse the received record. If there are any problems with it we just
520 * dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is
521 * resilient in the face of invalid records (e.g., invalid formatting,
522 * length, MAC, etc.). In general, invalid records SHOULD be silently
523 * discarded, thus preserving the association; however, an error MAY be
524 * logged for diagnostic purposes."
527 /* this packet contained a partial record, dump it */
528 if (n
< DTLS1_RT_HEADER_LENGTH
) {
529 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_RECORD_TOO_SMALL
);
534 s
->msg_callback(0, 0, SSL3_RT_HEADER
, buf
,
535 DTLS1_RT_HEADER_LENGTH
, s
, s
->msg_callback_arg
);
537 /* Get the record header */
538 if (!PACKET_get_1(&pkt
, &rectype
)
539 || !PACKET_get_1(&pkt
, &versmajor
)) {
540 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_LENGTH_MISMATCH
);
544 if (rectype
!= SSL3_RT_HANDSHAKE
) {
545 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_UNEXPECTED_MESSAGE
);
550 * Check record version number. We only check that the major version is
553 if (versmajor
!= DTLS1_VERSION_MAJOR
) {
554 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_BAD_PROTOCOL_VERSION_NUMBER
);
558 if (!PACKET_forward(&pkt
, 1)
559 /* Save the sequence number: 64 bits, with top 2 bytes = epoch */
560 || !PACKET_copy_bytes(&pkt
, seq
, SEQ_NUM_SIZE
)
561 || !PACKET_get_length_prefixed_2(&pkt
, &msgpkt
)) {
562 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_LENGTH_MISMATCH
);
566 * We allow data remaining at the end of the packet because there could
567 * be a second record (but we ignore it)
570 /* This is an initial ClientHello so the epoch has to be 0 */
571 if (seq
[0] != 0 || seq
[1] != 0) {
572 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_UNEXPECTED_MESSAGE
);
576 /* Get a pointer to the raw message for the later callback */
577 data
= PACKET_data(&msgpkt
);
579 /* Finished processing the record header, now process the message */
580 if (!PACKET_get_1(&msgpkt
, &msgtype
)
581 || !PACKET_get_net_3_len(&msgpkt
, &msglen
)
582 || !PACKET_get_net_2(&msgpkt
, &msgseq
)
583 || !PACKET_get_net_3_len(&msgpkt
, &fragoff
)
584 || !PACKET_get_net_3_len(&msgpkt
, &fraglen
)
585 || !PACKET_get_sub_packet(&msgpkt
, &msgpayload
, fraglen
)
586 || PACKET_remaining(&msgpkt
) != 0) {
587 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_LENGTH_MISMATCH
);
591 if (msgtype
!= SSL3_MT_CLIENT_HELLO
) {
592 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_UNEXPECTED_MESSAGE
);
596 /* Message sequence number can only be 0 or 1 */
598 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_INVALID_SEQUENCE_NUMBER
);
603 * We don't support fragment reassembly for ClientHellos whilst
604 * listening because that would require server side state (which is
605 * against the whole point of the ClientHello/HelloVerifyRequest
606 * mechanism). Instead we only look at the first ClientHello fragment
607 * and require that the cookie must be contained within it.
609 if (fragoff
!= 0 || fraglen
> msglen
) {
610 /* Non initial ClientHello fragment (or bad fragment) */
611 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_FRAGMENTED_CLIENT_HELLO
);
616 s
->msg_callback(0, s
->version
, SSL3_RT_HANDSHAKE
, data
,
617 fraglen
+ DTLS1_HM_HEADER_LENGTH
, s
,
618 s
->msg_callback_arg
);
620 if (!PACKET_get_net_2(&msgpayload
, &clientvers
)) {
621 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_LENGTH_MISMATCH
);
626 * Verify client version is supported
628 if (DTLS_VERSION_LT(clientvers
, (unsigned int)s
->method
->version
) &&
629 s
->method
->version
!= DTLS_ANY_VERSION
) {
630 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_WRONG_VERSION_NUMBER
);
634 if (!PACKET_forward(&msgpayload
, SSL3_RANDOM_SIZE
)
635 || !PACKET_get_length_prefixed_1(&msgpayload
, &session
)
636 || !PACKET_get_length_prefixed_1(&msgpayload
, &cookiepkt
)) {
638 * Could be malformed or the cookie does not fit within the initial
639 * ClientHello fragment. Either way we can't handle it.
641 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_LENGTH_MISMATCH
);
646 * Check if we have a cookie or not. If not we need to send a
647 * HelloVerifyRequest.
649 if (PACKET_remaining(&cookiepkt
) == 0) {
650 next
= LISTEN_SEND_VERIFY_REQUEST
;
653 * We have a cookie, so lets check it.
655 if (s
->ctx
->app_verify_cookie_cb
== NULL
) {
656 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_NO_VERIFY_COOKIE_CALLBACK
);
660 if (s
->ctx
->app_verify_cookie_cb(s
, PACKET_data(&cookiepkt
),
661 (unsigned int)PACKET_remaining(&cookiepkt
)) == 0) {
663 * We treat invalid cookies in the same was as no cookie as
666 next
= LISTEN_SEND_VERIFY_REQUEST
;
668 /* Cookie verification succeeded */
669 next
= LISTEN_SUCCESS
;
673 if (next
== LISTEN_SEND_VERIFY_REQUEST
) {
675 unsigned int version
;
679 * There was no cookie in the ClientHello so we need to send a
680 * HelloVerifyRequest. If this fails we do not worry about trying
681 * to resend, we just drop it.
685 * Dump the read packet, we don't need it any more. Ignore return
688 BIO_ctrl(SSL_get_rbio(s
), BIO_CTRL_DGRAM_SET_PEEK_MODE
, 0, NULL
);
689 BIO_read(rbio
, buf
, SSL3_RT_MAX_PLAIN_LENGTH
);
690 BIO_ctrl(SSL_get_rbio(s
), BIO_CTRL_DGRAM_SET_PEEK_MODE
, 1, NULL
);
692 /* Generate the cookie */
693 if (s
->ctx
->app_gen_cookie_cb
== NULL
||
694 s
->ctx
->app_gen_cookie_cb(s
, cookie
, &cookielen
) == 0 ||
696 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_COOKIE_GEN_CALLBACK_FAILURE
);
702 * Special case: for hello verify request, client version 1.0 and we
703 * haven't decided which version to use yet send back using version
704 * 1.0 header: otherwise some clients will ignore it.
706 version
= (s
->method
->version
== DTLS_ANY_VERSION
) ? DTLS1_VERSION
709 /* Construct the record and message headers */
710 if (!WPACKET_init(&wpkt
, s
->init_buf
)
711 || !WPACKET_put_bytes_u8(&wpkt
, SSL3_RT_HANDSHAKE
)
712 || !WPACKET_put_bytes_u16(&wpkt
, version
)
714 * Record sequence number is always the same as in the
715 * received ClientHello
717 || !WPACKET_memcpy(&wpkt
, seq
, SEQ_NUM_SIZE
)
718 /* End of record, start sub packet for message */
719 || !WPACKET_start_sub_packet_u16(&wpkt
)
721 || !WPACKET_put_bytes_u8(&wpkt
,
722 DTLS1_MT_HELLO_VERIFY_REQUEST
)
724 * Message length - doesn't follow normal TLS convention:
725 * the length isn't the last thing in the message header.
726 * We'll need to fill this in later when we know the
727 * length. Set it to zero for now
729 || !WPACKET_put_bytes_u24(&wpkt
, 0)
731 * Message sequence number is always 0 for a
734 || !WPACKET_put_bytes_u16(&wpkt
, 0)
736 * We never fragment a HelloVerifyRequest, so fragment
739 || !WPACKET_put_bytes_u24(&wpkt
, 0)
741 * Fragment length is the same as message length, but
742 * this *is* the last thing in the message header so we
743 * can just start a sub-packet. No need to come back
744 * later for this one.
746 || !WPACKET_start_sub_packet_u24(&wpkt
)
747 /* Create the actual HelloVerifyRequest body */
748 || !dtls_raw_hello_verify_request(&wpkt
, cookie
, cookielen
)
749 /* Close message body */
750 || !WPACKET_close(&wpkt
)
751 /* Close record body */
752 || !WPACKET_close(&wpkt
)
753 || !WPACKET_get_total_written(&wpkt
, &wreclen
)
754 || !WPACKET_finish(&wpkt
)) {
755 SSLerr(SSL_F_DTLSV1_LISTEN
, ERR_R_INTERNAL_ERROR
);
756 WPACKET_cleanup(&wpkt
);
762 * Fix up the message len in the message header. Its the same as the
763 * fragment len which has been filled in by WPACKET, so just copy
764 * that. Destination for the message len is after the record header
765 * plus one byte for the message content type. The source is the
766 * last 3 bytes of the message header
768 memcpy(&buf
[DTLS1_RT_HEADER_LENGTH
+ 1],
769 &buf
[DTLS1_RT_HEADER_LENGTH
+ DTLS1_HM_HEADER_LENGTH
- 3],
773 s
->msg_callback(1, 0, SSL3_RT_HEADER
, buf
,
774 DTLS1_RT_HEADER_LENGTH
, s
, s
->msg_callback_arg
);
776 if ((tmpclient
= BIO_ADDR_new()) == NULL
) {
777 SSLerr(SSL_F_DTLSV1_LISTEN
, ERR_R_MALLOC_FAILURE
);
782 * This is unnecessary if rbio and wbio are one and the same - but
783 * maybe they're not. We ignore errors here - some BIOs do not
786 if (BIO_dgram_get_peer(rbio
, tmpclient
) > 0) {
787 (void)BIO_dgram_set_peer(wbio
, tmpclient
);
789 BIO_ADDR_free(tmpclient
);
792 /* TODO(size_t): convert this call */
793 if (BIO_write(wbio
, buf
, wreclen
) < (int)wreclen
) {
794 if (BIO_should_retry(wbio
)) {
796 * Non-blocking IO...but we're stateless, so we're just
797 * going to drop this packet.
804 if (BIO_flush(wbio
) <= 0) {
805 if (BIO_should_retry(wbio
)) {
807 * Non-blocking IO...but we're stateless, so we're just
808 * going to drop this packet.
815 } while (next
!= LISTEN_SUCCESS
);
818 * Set expected sequence numbers to continue the handshake.
820 s
->d1
->handshake_read_seq
= 1;
821 s
->d1
->handshake_write_seq
= 1;
822 s
->d1
->next_handshake_write_seq
= 1;
823 DTLS_RECORD_LAYER_set_write_sequence(&s
->rlayer
, seq
);
826 * We are doing cookie exchange, so make sure we set that option in the
829 SSL_set_options(s
, SSL_OP_COOKIE_EXCHANGE
);
832 * Tell the state machine that we've done the initial hello verify
835 ossl_statem_set_hello_verify_done(s
);
838 * Some BIOs may not support this. If we fail we clear the client address
840 if (BIO_dgram_get_peer(rbio
, client
) <= 0)
841 BIO_ADDR_clear(client
);
846 BIO_ADDR_free(tmpclient
);
847 BIO_ctrl(SSL_get_rbio(s
), BIO_CTRL_DGRAM_SET_PEEK_MODE
, 0, NULL
);
849 /* Dump this packet. Ignore return value */
850 BIO_read(rbio
, buf
, SSL3_RT_MAX_PLAIN_LENGTH
);
856 static int dtls1_handshake_write(SSL
*s
)
858 return dtls1_do_write(s
, SSL3_RT_HANDSHAKE
);
861 int dtls1_shutdown(SSL
*s
)
864 #ifndef OPENSSL_NO_SCTP
867 wbio
= SSL_get_wbio(s
);
868 if (wbio
!= NULL
&& BIO_dgram_is_sctp(wbio
) &&
869 !(s
->shutdown
& SSL_SENT_SHUTDOWN
)) {
870 ret
= BIO_dgram_sctp_wait_for_dry(wbio
);
875 BIO_ctrl(SSL_get_wbio(s
), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN
, 1,
879 ret
= ssl3_shutdown(s
);
880 #ifndef OPENSSL_NO_SCTP
881 BIO_ctrl(SSL_get_wbio(s
), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN
, 0, NULL
);
886 int dtls1_query_mtu(SSL
*s
)
888 if (s
->d1
->link_mtu
) {
890 s
->d1
->link_mtu
- BIO_dgram_get_mtu_overhead(SSL_get_wbio(s
));
894 /* AHA! Figure out the MTU, and stick to the right size */
895 if (s
->d1
->mtu
< dtls1_min_mtu(s
)) {
896 if (!(SSL_get_options(s
) & SSL_OP_NO_QUERY_MTU
)) {
898 BIO_ctrl(SSL_get_wbio(s
), BIO_CTRL_DGRAM_QUERY_MTU
, 0, NULL
);
901 * I've seen the kernel return bogus numbers when it doesn't know
902 * (initial write), so just make sure we have a reasonable number
904 if (s
->d1
->mtu
< dtls1_min_mtu(s
)) {
906 s
->d1
->mtu
= dtls1_min_mtu(s
);
907 BIO_ctrl(SSL_get_wbio(s
), BIO_CTRL_DGRAM_SET_MTU
,
908 (long)s
->d1
->mtu
, NULL
);
916 static size_t dtls1_link_min_mtu(void)
918 return (g_probable_mtu
[(sizeof(g_probable_mtu
) /
919 sizeof(g_probable_mtu
[0])) - 1]);
922 size_t dtls1_min_mtu(SSL
*s
)
924 return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s
));
927 size_t DTLS_get_data_mtu(const SSL
*s
)
929 size_t mac_overhead
, int_overhead
, blocksize
, ext_overhead
;
930 const SSL_CIPHER
*ciph
= SSL_get_current_cipher(s
);
931 size_t mtu
= s
->d1
->mtu
;
936 if (!ssl_cipher_get_overhead(ciph
, &mac_overhead
, &int_overhead
,
937 &blocksize
, &ext_overhead
))
941 ext_overhead
+= mac_overhead
;
943 int_overhead
+= mac_overhead
;
945 /* Subtract external overhead (e.g. IV/nonce, separate MAC) */
946 if (ext_overhead
+ DTLS1_RT_HEADER_LENGTH
>= mtu
)
948 mtu
-= ext_overhead
+ DTLS1_RT_HEADER_LENGTH
;
950 /* Round encrypted payload down to cipher block size (for CBC etc.)
951 * No check for overflow since 'mtu % blocksize' cannot exceed mtu. */
953 mtu
-= (mtu
% blocksize
);
955 /* Subtract internal overhead (e.g. CBC padding len byte) */
956 if (int_overhead
>= mtu
)