2 * Copyright 2005-2018 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
12 #include <openssl/objects.h>
13 #include <openssl/rand.h>
14 #include "ssl_local.h"
16 static void get_current_time(struct timeval
*t
);
17 static int dtls1_handshake_write(SSL
*s
);
18 static size_t dtls1_link_min_mtu(void);
20 /* XDTLS: figure out the right values */
21 static const size_t g_probable_mtu
[] = { 1500, 512, 256 };
23 const SSL3_ENC_METHOD DTLSv1_enc_data
= {
27 tls1_generate_master_secret
,
28 tls1_change_cipher_state
,
29 tls1_final_finish_mac
,
30 TLS_MD_CLIENT_FINISH_CONST
, TLS_MD_CLIENT_FINISH_CONST_SIZE
,
31 TLS_MD_SERVER_FINISH_CONST
, TLS_MD_SERVER_FINISH_CONST_SIZE
,
33 tls1_export_keying_material
,
34 SSL_ENC_FLAG_DTLS
| SSL_ENC_FLAG_EXPLICIT_IV
,
35 dtls1_set_handshake_header
,
36 dtls1_close_construct_packet
,
40 const SSL3_ENC_METHOD DTLSv1_2_enc_data
= {
44 tls1_generate_master_secret
,
45 tls1_change_cipher_state
,
46 tls1_final_finish_mac
,
47 TLS_MD_CLIENT_FINISH_CONST
, TLS_MD_CLIENT_FINISH_CONST_SIZE
,
48 TLS_MD_SERVER_FINISH_CONST
, TLS_MD_SERVER_FINISH_CONST_SIZE
,
50 tls1_export_keying_material
,
51 SSL_ENC_FLAG_DTLS
| SSL_ENC_FLAG_EXPLICIT_IV
| SSL_ENC_FLAG_SIGALGS
52 | SSL_ENC_FLAG_SHA256_PRF
| SSL_ENC_FLAG_TLS1_2_CIPHERS
,
53 dtls1_set_handshake_header
,
54 dtls1_close_construct_packet
,
58 long dtls1_default_timeout(void)
61 * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for
62 * http, the cache would over fill
71 if (!DTLS_RECORD_LAYER_new(&s
->rlayer
)) {
77 if ((d1
= OPENSSL_zalloc(sizeof(*d1
))) == NULL
) {
82 d1
->buffered_messages
= pqueue_new();
83 d1
->sent_messages
= pqueue_new();
86 d1
->cookie_len
= sizeof(s
->d1
->cookie
);
92 if (d1
->buffered_messages
== NULL
|| d1
->sent_messages
== NULL
) {
93 pqueue_free(d1
->buffered_messages
);
94 pqueue_free(d1
->sent_messages
);
102 if (!s
->method
->ssl_clear(s
))
108 static void dtls1_clear_queues(SSL
*s
)
110 dtls1_clear_received_buffer(s
);
111 dtls1_clear_sent_buffer(s
);
114 void dtls1_clear_received_buffer(SSL
*s
)
117 hm_fragment
*frag
= NULL
;
119 while ((item
= pqueue_pop(s
->d1
->buffered_messages
)) != NULL
) {
120 frag
= (hm_fragment
*)item
->data
;
121 dtls1_hm_fragment_free(frag
);
126 void dtls1_clear_sent_buffer(SSL
*s
)
129 hm_fragment
*frag
= NULL
;
131 while ((item
= pqueue_pop(s
->d1
->sent_messages
)) != NULL
) {
132 frag
= (hm_fragment
*)item
->data
;
133 dtls1_hm_fragment_free(frag
);
139 void dtls1_free(SSL
*s
)
141 DTLS_RECORD_LAYER_free(&s
->rlayer
);
145 dtls1_clear_queues(s
);
147 pqueue_free(s
->d1
->buffered_messages
);
148 pqueue_free(s
->d1
->sent_messages
);
154 int dtls1_clear(SSL
*s
)
156 pqueue
*buffered_messages
;
157 pqueue
*sent_messages
;
161 DTLS_RECORD_LAYER_clear(&s
->rlayer
);
164 DTLS_timer_cb timer_cb
= s
->d1
->timer_cb
;
166 buffered_messages
= s
->d1
->buffered_messages
;
167 sent_messages
= s
->d1
->sent_messages
;
169 link_mtu
= s
->d1
->link_mtu
;
171 dtls1_clear_queues(s
);
173 memset(s
->d1
, 0, sizeof(*s
->d1
));
175 /* Restore the timer callback from previous state */
176 s
->d1
->timer_cb
= timer_cb
;
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
;
194 if (s
->method
->version
== DTLS_ANY_VERSION
)
195 s
->version
= DTLS_MAX_VERSION_INTERNAL
;
196 #ifndef OPENSSL_NO_DTLS1_METHOD
197 else if (s
->options
& SSL_OP_CISCO_ANYCONNECT
)
198 s
->client_version
= s
->version
= DTLS1_BAD_VER
;
201 s
->version
= s
->method
->version
;
206 long dtls1_ctrl(SSL
*s
, int cmd
, long larg
, void *parg
)
211 case DTLS_CTRL_GET_TIMEOUT
:
212 if (dtls1_get_timeout(s
, (struct timeval
*)parg
) != NULL
) {
216 case DTLS_CTRL_HANDLE_TIMEOUT
:
217 ret
= dtls1_handle_timeout(s
);
219 case DTLS_CTRL_SET_LINK_MTU
:
220 if (larg
< (long)dtls1_link_min_mtu())
222 s
->d1
->link_mtu
= larg
;
224 case DTLS_CTRL_GET_LINK_MIN_MTU
:
225 return (long)dtls1_link_min_mtu();
226 case SSL_CTRL_SET_MTU
:
228 * We may not have a BIO set yet so can't call dtls1_min_mtu()
229 * We'll have to make do with dtls1_link_min_mtu() and max overhead
231 if (larg
< (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD
)
236 ret
= ssl3_ctrl(s
, cmd
, larg
, parg
);
242 void dtls1_start_timer(SSL
*s
)
244 unsigned int sec
, usec
;
246 #ifndef OPENSSL_NO_SCTP
247 /* Disable timer for SCTP */
248 if (BIO_dgram_is_sctp(SSL_get_wbio(s
))) {
249 memset(&s
->d1
->next_timeout
, 0, sizeof(s
->d1
->next_timeout
));
255 * If timer is not set, initialize duration with 1 second or
256 * a user-specified value if the timer callback is installed.
258 if (s
->d1
->next_timeout
.tv_sec
== 0 && s
->d1
->next_timeout
.tv_usec
== 0) {
260 if (s
->d1
->timer_cb
!= NULL
)
261 s
->d1
->timeout_duration_us
= s
->d1
->timer_cb(s
, 0);
263 s
->d1
->timeout_duration_us
= 1000000;
266 /* Set timeout to current time */
267 get_current_time(&(s
->d1
->next_timeout
));
269 /* Add duration to current time */
271 sec
= s
->d1
->timeout_duration_us
/ 1000000;
272 usec
= s
->d1
->timeout_duration_us
- (sec
* 1000000);
274 s
->d1
->next_timeout
.tv_sec
+= sec
;
275 s
->d1
->next_timeout
.tv_usec
+= usec
;
277 if (s
->d1
->next_timeout
.tv_usec
>= 1000000) {
278 s
->d1
->next_timeout
.tv_sec
++;
279 s
->d1
->next_timeout
.tv_usec
-= 1000000;
282 BIO_ctrl(SSL_get_rbio(s
), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT
, 0,
283 &(s
->d1
->next_timeout
));
286 struct timeval
*dtls1_get_timeout(SSL
*s
, struct timeval
*timeleft
)
288 struct timeval timenow
;
290 /* If no timeout is set, just return NULL */
291 if (s
->d1
->next_timeout
.tv_sec
== 0 && s
->d1
->next_timeout
.tv_usec
== 0) {
295 /* Get current time */
296 get_current_time(&timenow
);
298 /* If timer already expired, set remaining time to 0 */
299 if (s
->d1
->next_timeout
.tv_sec
< timenow
.tv_sec
||
300 (s
->d1
->next_timeout
.tv_sec
== timenow
.tv_sec
&&
301 s
->d1
->next_timeout
.tv_usec
<= timenow
.tv_usec
)) {
302 memset(timeleft
, 0, sizeof(*timeleft
));
306 /* Calculate time left until timer expires */
307 memcpy(timeleft
, &(s
->d1
->next_timeout
), sizeof(struct timeval
));
308 timeleft
->tv_sec
-= timenow
.tv_sec
;
309 timeleft
->tv_usec
-= timenow
.tv_usec
;
310 if (timeleft
->tv_usec
< 0) {
312 timeleft
->tv_usec
+= 1000000;
316 * If remaining time is less than 15 ms, set it to 0 to prevent issues
317 * because of small divergences with socket timeouts.
319 if (timeleft
->tv_sec
== 0 && timeleft
->tv_usec
< 15000) {
320 memset(timeleft
, 0, sizeof(*timeleft
));
326 int dtls1_is_timer_expired(SSL
*s
)
328 struct timeval timeleft
;
330 /* Get time left until timeout, return false if no timer running */
331 if (dtls1_get_timeout(s
, &timeleft
) == NULL
) {
335 /* Return false if timer is not expired yet */
336 if (timeleft
.tv_sec
> 0 || timeleft
.tv_usec
> 0) {
340 /* Timer expired, so return true */
344 void dtls1_double_timeout(SSL
*s
)
346 s
->d1
->timeout_duration_us
*= 2;
347 if (s
->d1
->timeout_duration_us
> 60000000)
348 s
->d1
->timeout_duration_us
= 60000000;
349 dtls1_start_timer(s
);
352 void dtls1_stop_timer(SSL
*s
)
354 /* Reset everything */
355 memset(&s
->d1
->timeout
, 0, sizeof(s
->d1
->timeout
));
356 memset(&s
->d1
->next_timeout
, 0, sizeof(s
->d1
->next_timeout
));
357 s
->d1
->timeout_duration_us
= 1000000;
358 BIO_ctrl(SSL_get_rbio(s
), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT
, 0,
359 &(s
->d1
->next_timeout
));
360 /* Clear retransmission buffer */
361 dtls1_clear_sent_buffer(s
);
364 int dtls1_check_timeout_num(SSL
*s
)
368 s
->d1
->timeout
.num_alerts
++;
370 /* Reduce MTU after 2 unsuccessful retransmissions */
371 if (s
->d1
->timeout
.num_alerts
> 2
372 && !(SSL_get_options(s
) & SSL_OP_NO_QUERY_MTU
)) {
374 BIO_ctrl(SSL_get_wbio(s
), BIO_CTRL_DGRAM_GET_FALLBACK_MTU
, 0, NULL
);
375 if (mtu
< s
->d1
->mtu
)
379 if (s
->d1
->timeout
.num_alerts
> DTLS1_TMO_ALERT_COUNT
) {
380 /* fail the connection, enough alerts have been sent */
381 SSLfatal(s
, SSL_AD_NO_ALERT
, 0,
382 SSL_R_READ_TIMEOUT_EXPIRED
);
389 int dtls1_handle_timeout(SSL
*s
)
391 /* if no timer is expired, don't do anything */
392 if (!dtls1_is_timer_expired(s
)) {
396 if (s
->d1
->timer_cb
!= NULL
)
397 s
->d1
->timeout_duration_us
= s
->d1
->timer_cb(s
, s
->d1
->timeout_duration_us
);
399 dtls1_double_timeout(s
);
401 if (dtls1_check_timeout_num(s
) < 0) {
402 /* SSLfatal() already called */
406 s
->d1
->timeout
.read_timeouts
++;
407 if (s
->d1
->timeout
.read_timeouts
> DTLS1_TMO_READ_COUNT
) {
408 s
->d1
->timeout
.read_timeouts
= 1;
411 dtls1_start_timer(s
);
412 /* Calls SSLfatal() if required */
413 return dtls1_retransmit_buffered_messages(s
);
416 static void get_current_time(struct timeval
*t
)
426 SystemTimeToFileTime(&st
, &now
.ft
);
427 /* re-bias to 1/1/1970 */
429 now
.ul
-= 116444736000000000ULL;
432 now
.ul
-= 116444736000000000UI
64;
435 t
->tv_sec
= (long)(now
.ul
/ 10000000);
436 t
->tv_usec
= ((int)(now
.ul
% 10000000)) / 10;
438 gettimeofday(t
, NULL
);
442 #define LISTEN_SUCCESS 2
443 #define LISTEN_SEND_VERIFY_REQUEST 1
445 #ifndef OPENSSL_NO_SOCK
446 int DTLSv1_listen(SSL
*s
, BIO_ADDR
*client
)
448 int next
, n
, ret
= 0;
449 unsigned char cookie
[DTLS1_COOKIE_LENGTH
];
450 unsigned char seq
[SEQ_NUM_SIZE
];
451 const unsigned char *data
;
452 unsigned char *buf
, *wbuf
;
453 size_t fragoff
, fraglen
, msglen
, reclen
, align
= 0;
454 unsigned int rectype
, versmajor
, msgseq
, msgtype
, clientvers
, cookielen
;
456 BIO_ADDR
*tmpclient
= NULL
;
457 PACKET pkt
, msgpkt
, msgpayload
, session
, cookiepkt
;
459 if (s
->handshake_func
== NULL
) {
460 /* Not properly initialized yet */
461 SSL_set_accept_state(s
);
464 /* Ensure there is no state left over from a previous invocation */
470 rbio
= SSL_get_rbio(s
);
471 wbio
= SSL_get_wbio(s
);
473 if (!rbio
|| !wbio
) {
474 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_BIO_NOT_SET
);
479 * Note: This check deliberately excludes DTLS1_BAD_VER because that version
480 * requires the MAC to be calculated *including* the first ClientHello
481 * (without the cookie). Since DTLSv1_listen is stateless that cannot be
482 * supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via
485 if ((s
->version
& 0xff00) != (DTLS1_VERSION
& 0xff00)) {
486 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_UNSUPPORTED_SSL_VERSION
);
490 if (!ssl3_setup_buffers(s
)) {
491 /* SSLerr already called */
494 buf
= RECORD_LAYER_get_rbuf(&s
->rlayer
)->buf
;
495 wbuf
= RECORD_LAYER_get_wbuf(&s
->rlayer
)[0].buf
;
496 #if defined(SSL3_ALIGN_PAYLOAD)
497 # if SSL3_ALIGN_PAYLOAD != 0
499 * Using SSL3_RT_HEADER_LENGTH here instead of DTLS1_RT_HEADER_LENGTH for
500 * consistency with ssl3_read_n. In practice it should make no difference
501 * for sensible values of SSL3_ALIGN_PAYLOAD because the difference between
502 * SSL3_RT_HEADER_LENGTH and DTLS1_RT_HEADER_LENGTH is exactly 8
504 align
= (size_t)buf
+ SSL3_RT_HEADER_LENGTH
;
505 align
= SSL3_ALIGN_PAYLOAD
- 1 - ((align
- 1) % SSL3_ALIGN_PAYLOAD
);
514 n
= BIO_read(rbio
, buf
, SSL3_RT_MAX_PLAIN_LENGTH
515 + DTLS1_RT_HEADER_LENGTH
);
517 if (BIO_should_retry(rbio
)) {
518 /* Non-blocking IO */
524 if (!PACKET_buf_init(&pkt
, buf
, n
)) {
525 SSLerr(SSL_F_DTLSV1_LISTEN
, ERR_R_INTERNAL_ERROR
);
530 * Parse the received record. If there are any problems with it we just
531 * dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is
532 * resilient in the face of invalid records (e.g., invalid formatting,
533 * length, MAC, etc.). In general, invalid records SHOULD be silently
534 * discarded, thus preserving the association; however, an error MAY be
535 * logged for diagnostic purposes."
538 /* this packet contained a partial record, dump it */
539 if (n
< DTLS1_RT_HEADER_LENGTH
) {
540 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_RECORD_TOO_SMALL
);
545 s
->msg_callback(0, 0, SSL3_RT_HEADER
, buf
,
546 DTLS1_RT_HEADER_LENGTH
, s
, s
->msg_callback_arg
);
548 /* Get the record header */
549 if (!PACKET_get_1(&pkt
, &rectype
)
550 || !PACKET_get_1(&pkt
, &versmajor
)) {
551 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_LENGTH_MISMATCH
);
555 if (rectype
!= SSL3_RT_HANDSHAKE
) {
556 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_UNEXPECTED_MESSAGE
);
561 * Check record version number. We only check that the major version is
564 if (versmajor
!= DTLS1_VERSION_MAJOR
) {
565 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_BAD_PROTOCOL_VERSION_NUMBER
);
569 if (!PACKET_forward(&pkt
, 1)
570 /* Save the sequence number: 64 bits, with top 2 bytes = epoch */
571 || !PACKET_copy_bytes(&pkt
, seq
, SEQ_NUM_SIZE
)
572 || !PACKET_get_length_prefixed_2(&pkt
, &msgpkt
)) {
573 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_LENGTH_MISMATCH
);
576 reclen
= PACKET_remaining(&msgpkt
);
578 * We allow data remaining at the end of the packet because there could
579 * be a second record (but we ignore it)
582 /* This is an initial ClientHello so the epoch has to be 0 */
583 if (seq
[0] != 0 || seq
[1] != 0) {
584 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_UNEXPECTED_MESSAGE
);
588 /* Get a pointer to the raw message for the later callback */
589 data
= PACKET_data(&msgpkt
);
591 /* Finished processing the record header, now process the message */
592 if (!PACKET_get_1(&msgpkt
, &msgtype
)
593 || !PACKET_get_net_3_len(&msgpkt
, &msglen
)
594 || !PACKET_get_net_2(&msgpkt
, &msgseq
)
595 || !PACKET_get_net_3_len(&msgpkt
, &fragoff
)
596 || !PACKET_get_net_3_len(&msgpkt
, &fraglen
)
597 || !PACKET_get_sub_packet(&msgpkt
, &msgpayload
, fraglen
)
598 || PACKET_remaining(&msgpkt
) != 0) {
599 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_LENGTH_MISMATCH
);
603 if (msgtype
!= SSL3_MT_CLIENT_HELLO
) {
604 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_UNEXPECTED_MESSAGE
);
608 /* Message sequence number can only be 0 or 1 */
610 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_INVALID_SEQUENCE_NUMBER
);
615 * We don't support fragment reassembly for ClientHellos whilst
616 * listening because that would require server side state (which is
617 * against the whole point of the ClientHello/HelloVerifyRequest
618 * mechanism). Instead we only look at the first ClientHello fragment
619 * and require that the cookie must be contained within it.
621 if (fragoff
!= 0 || fraglen
> msglen
) {
622 /* Non initial ClientHello fragment (or bad fragment) */
623 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_FRAGMENTED_CLIENT_HELLO
);
628 s
->msg_callback(0, s
->version
, SSL3_RT_HANDSHAKE
, data
,
629 fraglen
+ DTLS1_HM_HEADER_LENGTH
, s
,
630 s
->msg_callback_arg
);
632 if (!PACKET_get_net_2(&msgpayload
, &clientvers
)) {
633 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_LENGTH_MISMATCH
);
638 * Verify client version is supported
640 if (DTLS_VERSION_LT(clientvers
, (unsigned int)s
->method
->version
) &&
641 s
->method
->version
!= DTLS_ANY_VERSION
) {
642 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_WRONG_VERSION_NUMBER
);
646 if (!PACKET_forward(&msgpayload
, SSL3_RANDOM_SIZE
)
647 || !PACKET_get_length_prefixed_1(&msgpayload
, &session
)
648 || !PACKET_get_length_prefixed_1(&msgpayload
, &cookiepkt
)) {
650 * Could be malformed or the cookie does not fit within the initial
651 * ClientHello fragment. Either way we can't handle it.
653 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_LENGTH_MISMATCH
);
658 * Check if we have a cookie or not. If not we need to send a
659 * HelloVerifyRequest.
661 if (PACKET_remaining(&cookiepkt
) == 0) {
662 next
= LISTEN_SEND_VERIFY_REQUEST
;
665 * We have a cookie, so lets check it.
667 if (s
->ctx
->app_verify_cookie_cb
== NULL
) {
668 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_NO_VERIFY_COOKIE_CALLBACK
);
672 if (s
->ctx
->app_verify_cookie_cb(s
, PACKET_data(&cookiepkt
),
673 (unsigned int)PACKET_remaining(&cookiepkt
)) == 0) {
675 * We treat invalid cookies in the same was as no cookie as
678 next
= LISTEN_SEND_VERIFY_REQUEST
;
680 /* Cookie verification succeeded */
681 next
= LISTEN_SUCCESS
;
685 if (next
== LISTEN_SEND_VERIFY_REQUEST
) {
687 unsigned int version
;
691 * There was no cookie in the ClientHello so we need to send a
692 * HelloVerifyRequest. If this fails we do not worry about trying
693 * to resend, we just drop it.
696 /* Generate the cookie */
697 if (s
->ctx
->app_gen_cookie_cb
== NULL
||
698 s
->ctx
->app_gen_cookie_cb(s
, cookie
, &cookielen
) == 0 ||
700 SSLerr(SSL_F_DTLSV1_LISTEN
, SSL_R_COOKIE_GEN_CALLBACK_FAILURE
);
706 * Special case: for hello verify request, client version 1.0 and we
707 * haven't decided which version to use yet send back using version
708 * 1.0 header: otherwise some clients will ignore it.
710 version
= (s
->method
->version
== DTLS_ANY_VERSION
) ? DTLS1_VERSION
713 /* Construct the record and message headers */
714 if (!WPACKET_init_static_len(&wpkt
,
716 ssl_get_max_send_fragment(s
)
717 + DTLS1_RT_HEADER_LENGTH
,
719 || !WPACKET_put_bytes_u8(&wpkt
, SSL3_RT_HANDSHAKE
)
720 || !WPACKET_put_bytes_u16(&wpkt
, version
)
722 * Record sequence number is always the same as in the
723 * received ClientHello
725 || !WPACKET_memcpy(&wpkt
, seq
, SEQ_NUM_SIZE
)
726 /* End of record, start sub packet for message */
727 || !WPACKET_start_sub_packet_u16(&wpkt
)
729 || !WPACKET_put_bytes_u8(&wpkt
,
730 DTLS1_MT_HELLO_VERIFY_REQUEST
)
732 * Message length - doesn't follow normal TLS convention:
733 * the length isn't the last thing in the message header.
734 * We'll need to fill this in later when we know the
735 * length. Set it to zero for now
737 || !WPACKET_put_bytes_u24(&wpkt
, 0)
739 * Message sequence number is always 0 for a
742 || !WPACKET_put_bytes_u16(&wpkt
, 0)
744 * We never fragment a HelloVerifyRequest, so fragment
747 || !WPACKET_put_bytes_u24(&wpkt
, 0)
749 * Fragment length is the same as message length, but
750 * this *is* the last thing in the message header so we
751 * can just start a sub-packet. No need to come back
752 * later for this one.
754 || !WPACKET_start_sub_packet_u24(&wpkt
)
755 /* Create the actual HelloVerifyRequest body */
756 || !dtls_raw_hello_verify_request(&wpkt
, cookie
, cookielen
)
757 /* Close message body */
758 || !WPACKET_close(&wpkt
)
759 /* Close record body */
760 || !WPACKET_close(&wpkt
)
761 || !WPACKET_get_total_written(&wpkt
, &wreclen
)
762 || !WPACKET_finish(&wpkt
)) {
763 SSLerr(SSL_F_DTLSV1_LISTEN
, ERR_R_INTERNAL_ERROR
);
764 WPACKET_cleanup(&wpkt
);
770 * Fix up the message len in the message header. Its the same as the
771 * fragment len which has been filled in by WPACKET, so just copy
772 * that. Destination for the message len is after the record header
773 * plus one byte for the message content type. The source is the
774 * last 3 bytes of the message header
776 memcpy(&wbuf
[DTLS1_RT_HEADER_LENGTH
+ 1],
777 &wbuf
[DTLS1_RT_HEADER_LENGTH
+ DTLS1_HM_HEADER_LENGTH
- 3],
781 s
->msg_callback(1, 0, SSL3_RT_HEADER
, buf
,
782 DTLS1_RT_HEADER_LENGTH
, s
, s
->msg_callback_arg
);
784 if ((tmpclient
= BIO_ADDR_new()) == NULL
) {
785 SSLerr(SSL_F_DTLSV1_LISTEN
, ERR_R_MALLOC_FAILURE
);
790 * This is unnecessary if rbio and wbio are one and the same - but
791 * maybe they're not. We ignore errors here - some BIOs do not
794 if (BIO_dgram_get_peer(rbio
, tmpclient
) > 0) {
795 (void)BIO_dgram_set_peer(wbio
, tmpclient
);
797 BIO_ADDR_free(tmpclient
);
800 /* TODO(size_t): convert this call */
801 if (BIO_write(wbio
, wbuf
, wreclen
) < (int)wreclen
) {
802 if (BIO_should_retry(wbio
)) {
804 * Non-blocking IO...but we're stateless, so we're just
805 * going to drop this packet.
812 if (BIO_flush(wbio
) <= 0) {
813 if (BIO_should_retry(wbio
)) {
815 * Non-blocking IO...but we're stateless, so we're just
816 * going to drop this packet.
823 } while (next
!= LISTEN_SUCCESS
);
826 * Set expected sequence numbers to continue the handshake.
828 s
->d1
->handshake_read_seq
= 1;
829 s
->d1
->handshake_write_seq
= 1;
830 s
->d1
->next_handshake_write_seq
= 1;
831 DTLS_RECORD_LAYER_set_write_sequence(&s
->rlayer
, seq
);
834 * We are doing cookie exchange, so make sure we set that option in the
837 SSL_set_options(s
, SSL_OP_COOKIE_EXCHANGE
);
840 * Tell the state machine that we've done the initial hello verify
843 ossl_statem_set_hello_verify_done(s
);
846 * Some BIOs may not support this. If we fail we clear the client address
848 if (BIO_dgram_get_peer(rbio
, client
) <= 0)
849 BIO_ADDR_clear(client
);
851 /* Buffer the record in the processed_rcds queue */
852 if (!dtls_buffer_listen_record(s
, reclen
, seq
, align
))
857 BIO_ADDR_free(tmpclient
);
862 static int dtls1_handshake_write(SSL
*s
)
864 return dtls1_do_write(s
, SSL3_RT_HANDSHAKE
);
867 int dtls1_shutdown(SSL
*s
)
870 #ifndef OPENSSL_NO_SCTP
873 wbio
= SSL_get_wbio(s
);
874 if (wbio
!= NULL
&& BIO_dgram_is_sctp(wbio
) &&
875 !(s
->shutdown
& SSL_SENT_SHUTDOWN
)) {
876 ret
= BIO_dgram_sctp_wait_for_dry(wbio
);
881 BIO_ctrl(SSL_get_wbio(s
), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN
, 1,
885 ret
= ssl3_shutdown(s
);
886 #ifndef OPENSSL_NO_SCTP
887 BIO_ctrl(SSL_get_wbio(s
), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN
, 0, NULL
);
892 int dtls1_query_mtu(SSL
*s
)
894 if (s
->d1
->link_mtu
) {
896 s
->d1
->link_mtu
- BIO_dgram_get_mtu_overhead(SSL_get_wbio(s
));
900 /* AHA! Figure out the MTU, and stick to the right size */
901 if (s
->d1
->mtu
< dtls1_min_mtu(s
)) {
902 if (!(SSL_get_options(s
) & SSL_OP_NO_QUERY_MTU
)) {
904 BIO_ctrl(SSL_get_wbio(s
), BIO_CTRL_DGRAM_QUERY_MTU
, 0, NULL
);
907 * I've seen the kernel return bogus numbers when it doesn't know
908 * (initial write), so just make sure we have a reasonable number
910 if (s
->d1
->mtu
< dtls1_min_mtu(s
)) {
912 s
->d1
->mtu
= dtls1_min_mtu(s
);
913 BIO_ctrl(SSL_get_wbio(s
), BIO_CTRL_DGRAM_SET_MTU
,
914 (long)s
->d1
->mtu
, NULL
);
922 static size_t dtls1_link_min_mtu(void)
924 return (g_probable_mtu
[(sizeof(g_probable_mtu
) /
925 sizeof(g_probable_mtu
[0])) - 1]);
928 size_t dtls1_min_mtu(SSL
*s
)
930 return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s
));
933 size_t DTLS_get_data_mtu(const SSL
*s
)
935 size_t mac_overhead
, int_overhead
, blocksize
, ext_overhead
;
936 const SSL_CIPHER
*ciph
= SSL_get_current_cipher(s
);
937 size_t mtu
= s
->d1
->mtu
;
942 if (!ssl_cipher_get_overhead(ciph
, &mac_overhead
, &int_overhead
,
943 &blocksize
, &ext_overhead
))
947 ext_overhead
+= mac_overhead
;
949 int_overhead
+= mac_overhead
;
951 /* Subtract external overhead (e.g. IV/nonce, separate MAC) */
952 if (ext_overhead
+ DTLS1_RT_HEADER_LENGTH
>= mtu
)
954 mtu
-= ext_overhead
+ DTLS1_RT_HEADER_LENGTH
;
956 /* Round encrypted payload down to cipher block size (for CBC etc.)
957 * No check for overflow since 'mtu % blocksize' cannot exceed mtu. */
959 mtu
-= (mtu
% blocksize
);
961 /* Subtract internal overhead (e.g. CBC padding len byte) */
962 if (int_overhead
>= mtu
)
969 void DTLS_set_timer_cb(SSL
*s
, DTLS_timer_cb cb
)
971 s
->d1
->timer_cb
= cb
;