3 * DTLS implementation written by Nagendra Modadugu
4 * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
6 /* ====================================================================
7 * Copyright (c) 1998-2005 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).
59 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
60 * All rights reserved.
62 * This package is an SSL implementation written
63 * by Eric Young (eay@cryptsoft.com).
64 * The implementation was written so as to conform with Netscapes SSL.
66 * This library is free for commercial and non-commercial use as long as
67 * the following conditions are aheared to. The following conditions
68 * apply to all code found in this distribution, be it the RC4, RSA,
69 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
70 * included with this distribution is covered by the same copyright terms
71 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
73 * Copyright remains Eric Young's, and as such any Copyright notices in
74 * the code are not to be removed.
75 * If this package is used in a product, Eric Young should be given attribution
76 * as the author of the parts of the library used.
77 * This can be in the form of a textual message at program startup or
78 * in documentation (online or textual) provided with the package.
80 * Redistribution and use in source and binary forms, with or without
81 * modification, are permitted provided that the following conditions
83 * 1. Redistributions of source code must retain the copyright
84 * notice, this list of conditions and the following disclaimer.
85 * 2. Redistributions in binary form must reproduce the above copyright
86 * notice, this list of conditions and the following disclaimer in the
87 * documentation and/or other materials provided with the distribution.
88 * 3. All advertising materials mentioning features or use of this software
89 * must display the following acknowledgement:
90 * "This product includes cryptographic software written by
91 * Eric Young (eay@cryptsoft.com)"
92 * The word 'cryptographic' can be left out if the rouines from the library
93 * being used are not cryptographic related :-).
94 * 4. If you include any Windows specific code (or a derivative thereof) from
95 * the apps directory (application code) you must include an acknowledgement:
96 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
98 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
99 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
100 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
101 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
102 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
103 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
104 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
105 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
106 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
107 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
110 * The licence and distribution terms for any publically available version or
111 * derivative of this code cannot be changed. i.e. this code cannot simply be
112 * copied and put under another distribution licence
113 * [including the GNU Public Licence.]
119 #include "ssl_locl.h"
120 #include <openssl/buffer.h>
121 #include <openssl/rand.h>
122 #include <openssl/objects.h>
123 #include <openssl/evp.h>
124 #include <openssl/x509.h>
126 #define RSMBLY_BITMASK_SIZE(msg_len) (((msg_len) + 7) / 8)
128 #define RSMBLY_BITMASK_MARK(bitmask, start, end) { \
129 if ((end) - (start) <= 8) { \
131 for (ii = (start); ii < (end); ii++) bitmask[((ii) >> 3)] |= (1 << ((ii) & 7)); \
134 bitmask[((start) >> 3)] |= bitmask_start_values[((start) & 7)]; \
135 for (ii = (((start) >> 3) + 1); ii < ((((end) - 1)) >> 3); ii++) bitmask[ii] = 0xff; \
136 bitmask[(((end) - 1) >> 3)] |= bitmask_end_values[((end) & 7)]; \
139 #define RSMBLY_BITMASK_IS_COMPLETE(bitmask, msg_len, is_complete) { \
141 OPENSSL_assert((msg_len) > 0); \
143 if (bitmask[(((msg_len) - 1) >> 3)] != bitmask_end_values[((msg_len) & 7)]) is_complete = 0; \
144 if (is_complete) for (ii = (((msg_len) - 1) >> 3) - 1; ii >= 0 ; ii--) \
145 if (bitmask[ii] != 0xff) { is_complete = 0; break; } }
148 #define RSMBLY_BITMASK_PRINT(bitmask, msg_len) { \
150 printf("bitmask: "); for (ii = 0; ii < (msg_len); ii++) \
151 printf("%d ", (bitmask[ii >> 3] & (1 << (ii & 7))) >> (ii & 7)); \
155 static unsigned char bitmask_start_values[] = {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80};
156 static unsigned char bitmask_end_values[] = {0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f};
158 /* XDTLS: figure out the right values */
159 static unsigned int g_probable_mtu[] = {1500 - 28, 512 - 28, 256 - 28};
161 static unsigned int dtls1_guess_mtu(unsigned int curr_mtu);
162 static void dtls1_fix_message_header(SSL *s, unsigned long frag_off,
163 unsigned long frag_len);
164 static unsigned char *dtls1_write_message_header(SSL *s,
166 static void dtls1_set_message_header_int(SSL *s, unsigned char mt,
167 unsigned long len, unsigned short seq_num, unsigned long frag_off,
168 unsigned long frag_len);
169 static long dtls1_get_message_fragment(SSL *s, int st1, int stn,
173 dtls1_hm_fragment_new(unsigned long frag_len, int reassembly)
175 hm_fragment *frag = NULL;
176 unsigned char *buf = NULL;
177 unsigned char *bitmask = NULL;
179 frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment));
185 buf = (unsigned char *)OPENSSL_malloc(frag_len);
193 /* zero length fragment gets zero frag->fragment */
194 frag->fragment = buf;
196 /* Initialize reassembly bitmask if necessary */
199 bitmask = (unsigned char *)OPENSSL_malloc(RSMBLY_BITMASK_SIZE(frag_len));
202 if (buf != NULL) OPENSSL_free(buf);
206 memset(bitmask, 0, RSMBLY_BITMASK_SIZE(frag_len));
209 frag->reassembly = bitmask;
215 dtls1_hm_fragment_free(hm_fragment *frag)
218 if (frag->msg_header.is_ccs)
220 EVP_CIPHER_CTX_free(frag->msg_header.saved_retransmit_state.enc_write_ctx);
221 EVP_MD_CTX_destroy(frag->msg_header.saved_retransmit_state.write_hash);
223 if (frag->fragment) OPENSSL_free(frag->fragment);
224 if (frag->reassembly) OPENSSL_free(frag->reassembly);
228 /* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
229 int dtls1_do_write(SSL *s, int type)
233 unsigned int len, frag_off, mac_size, blocksize;
235 /* AHA! Figure out the MTU, and stick to the right size */
236 if (s->d1->mtu < dtls1_min_mtu() && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
239 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
241 /* I've seen the kernel return bogus numbers when it doesn't know
242 * (initial write), so just make sure we have a reasonable number */
243 if (s->d1->mtu < dtls1_min_mtu())
246 s->d1->mtu = dtls1_guess_mtu(s->d1->mtu);
247 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
254 fprintf(stderr, "using MTU = %d\n", mtu);
256 mtu -= (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
258 curr_mtu = mtu - BIO_wpending(SSL_get_wbio(s));
262 else if ( ( ret = BIO_flush(SSL_get_wbio(s))) <= 0)
265 if ( BIO_wpending(SSL_get_wbio(s)) + s->init_num >= mtu)
267 ret = BIO_flush(SSL_get_wbio(s));
270 mtu = s->d1->mtu - (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
274 OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu()); /* should have something reasonable now */
276 if ( s->init_off == 0 && type == SSL3_RT_HANDSHAKE)
277 OPENSSL_assert(s->init_num ==
278 (int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH);
282 if (s->enc_write_ctx && EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_GCM_MODE)
285 mac_size = EVP_MD_CTX_size(s->write_hash);
290 if (s->enc_write_ctx &&
291 (EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_CBC_MODE))
292 blocksize = 2 * EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
299 curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) -
300 DTLS1_RT_HEADER_LENGTH - mac_size - blocksize;
302 if ( curr_mtu <= DTLS1_HM_HEADER_LENGTH)
304 /* grr.. we could get an error if MTU picked was wrong */
305 ret = BIO_flush(SSL_get_wbio(s));
308 curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH -
309 mac_size - blocksize;
312 if ( s->init_num > curr_mtu)
318 /* XDTLS: this function is too long. split out the CCS part */
319 if ( type == SSL3_RT_HANDSHAKE)
321 if ( s->init_off != 0)
323 OPENSSL_assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
324 s->init_off -= DTLS1_HM_HEADER_LENGTH;
325 s->init_num += DTLS1_HM_HEADER_LENGTH;
327 if ( s->init_num > curr_mtu)
333 dtls1_fix_message_header(s, frag_off,
334 len - DTLS1_HM_HEADER_LENGTH);
336 dtls1_write_message_header(s, (unsigned char *)&s->init_buf->data[s->init_off]);
338 OPENSSL_assert(len >= DTLS1_HM_HEADER_LENGTH);
341 ret=dtls1_write_bytes(s,type,&s->init_buf->data[s->init_off],
345 /* might need to update MTU here, but we don't know
346 * which previous packet caused the failure -- so can't
347 * really retransmit anything. continue as if everything
348 * is fine and wait for an alert to handle the
351 if ( BIO_ctrl(SSL_get_wbio(s),
352 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0 )
353 s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
354 BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
361 /* bad if this assert fails, only part of the handshake
362 * message got sent. but why would this happen? */
363 OPENSSL_assert(len == (unsigned int)ret);
365 if (type == SSL3_RT_HANDSHAKE && ! s->d1->retransmitting)
367 /* should not be done for 'Hello Request's, but in that case
368 * we'll ignore the result anyway */
369 unsigned char *p = (unsigned char *)&s->init_buf->data[s->init_off];
370 const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
373 if (frag_off == 0 && s->version != DTLS1_BAD_VER)
375 /* reconstruct message header is if it
376 * is being sent in single fragment */
377 *p++ = msg_hdr->type;
378 l2n3(msg_hdr->msg_len,p);
379 s2n (msg_hdr->seq,p);
381 l2n3(msg_hdr->msg_len,p);
382 p -= DTLS1_HM_HEADER_LENGTH;
387 p += DTLS1_HM_HEADER_LENGTH;
388 xlen = ret - DTLS1_HM_HEADER_LENGTH;
391 ssl3_finish_mac(s, p, xlen);
394 if (ret == s->init_num)
397 s->msg_callback(1, s->version, type, s->init_buf->data,
398 (size_t)(s->init_off + s->init_num), s,
399 s->msg_callback_arg);
401 s->init_off = 0; /* done writing this message */
408 frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
415 /* Obtain handshake message of message type 'mt' (any if mt == -1),
416 * maximum acceptable body length 'max'.
417 * Read an entire handshake message. Handshake messages arrive in
420 long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
423 struct hm_header_st *msg_hdr;
425 unsigned long msg_len;
427 /* s3->tmp is used to store messages that are unexpected, caused
428 * by the absence of an optional handshake message */
429 if (s->s3->tmp.reuse_message)
431 s->s3->tmp.reuse_message=0;
432 if ((mt >= 0) && (s->s3->tmp.message_type != mt))
434 al=SSL_AD_UNEXPECTED_MESSAGE;
435 SSLerr(SSL_F_DTLS1_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
439 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
440 s->init_num = (int)s->s3->tmp.message_size;
444 msg_hdr = &s->d1->r_msg_hdr;
445 memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
448 i = dtls1_get_message_fragment(s, st1, stn, max, ok);
449 if ( i == DTLS1_HM_BAD_FRAGMENT ||
450 i == DTLS1_HM_FRAGMENT_RETRY) /* bad fragment received */
452 else if ( i <= 0 && !*ok)
455 p = (unsigned char *)s->init_buf->data;
456 msg_len = msg_hdr->msg_len;
458 /* reconstruct message header */
459 *(p++) = msg_hdr->type;
461 s2n (msg_hdr->seq,p);
464 if (s->version != DTLS1_BAD_VER) {
465 p -= DTLS1_HM_HEADER_LENGTH;
466 msg_len += DTLS1_HM_HEADER_LENGTH;
469 ssl3_finish_mac(s, p, msg_len);
471 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
473 s, s->msg_callback_arg);
475 memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
477 /* Don't change sequence numbers while listening */
479 s->d1->handshake_read_seq++;
481 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
485 ssl3_send_alert(s,SSL3_AL_FATAL,al);
491 static int dtls1_preprocess_fragment(SSL *s,struct hm_header_st *msg_hdr,int max)
493 size_t frag_off,frag_len,msg_len;
495 msg_len = msg_hdr->msg_len;
496 frag_off = msg_hdr->frag_off;
497 frag_len = msg_hdr->frag_len;
499 /* sanity checking */
500 if ( (frag_off+frag_len) > msg_len)
502 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
503 return SSL_AD_ILLEGAL_PARAMETER;
506 if ( (frag_off+frag_len) > (unsigned long)max)
508 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
509 return SSL_AD_ILLEGAL_PARAMETER;
512 if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */
514 /* msg_len is limited to 2^24, but is effectively checked
515 * against max above */
516 if (!BUF_MEM_grow_clean(s->init_buf,msg_len+DTLS1_HM_HEADER_LENGTH))
518 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,ERR_R_BUF_LIB);
519 return SSL_AD_INTERNAL_ERROR;
522 s->s3->tmp.message_size = msg_len;
523 s->d1->r_msg_hdr.msg_len = msg_len;
524 s->s3->tmp.message_type = msg_hdr->type;
525 s->d1->r_msg_hdr.type = msg_hdr->type;
526 s->d1->r_msg_hdr.seq = msg_hdr->seq;
528 else if (msg_len != s->d1->r_msg_hdr.msg_len)
530 /* They must be playing with us! BTW, failure to enforce
531 * upper limit would open possibility for buffer overrun. */
532 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
533 return SSL_AD_ILLEGAL_PARAMETER;
536 return 0; /* no error */
541 dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok)
543 /* (0) check whether the desired fragment is available
545 * (1) copy over the fragment to s->init_buf->data[]
546 * (2) update s->init_num
553 item = pqueue_peek(s->d1->buffered_messages);
557 frag = (hm_fragment *)item->data;
559 /* Don't return if reassembly still in progress */
560 if (frag->reassembly != NULL)
563 if ( s->d1->handshake_read_seq == frag->msg_header.seq)
565 unsigned long frag_len = frag->msg_header.frag_len;
566 pqueue_pop(s->d1->buffered_messages);
568 al=dtls1_preprocess_fragment(s,&frag->msg_header,max);
570 if (al==0) /* no alert */
572 unsigned char *p = (unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
573 memcpy(&p[frag->msg_header.frag_off],
574 frag->fragment,frag->msg_header.frag_len);
577 dtls1_hm_fragment_free(frag);
586 ssl3_send_alert(s,SSL3_AL_FATAL,al);
595 /* dtls1_max_handshake_message_len returns the maximum number of bytes
596 * permitted in a DTLS handshake message for |s|. The minimum is 16KB, but may
597 * be greater if the maximum certificate list size requires it. */
598 static unsigned long dtls1_max_handshake_message_len(const SSL *s)
600 unsigned long max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
601 if (max_len < (unsigned long)s->max_cert_list)
602 return s->max_cert_list;
607 dtls1_reassemble_fragment(SSL *s, struct hm_header_st* msg_hdr, int *ok)
609 hm_fragment *frag = NULL;
611 int i = -1, is_complete;
612 unsigned char seq64be[8];
613 unsigned long frag_len = msg_hdr->frag_len;
615 if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len ||
616 msg_hdr->msg_len > dtls1_max_handshake_message_len(s))
620 return DTLS1_HM_FRAGMENT_RETRY;
622 /* Try to find item in queue */
623 memset(seq64be,0,sizeof(seq64be));
624 seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
625 seq64be[7] = (unsigned char) msg_hdr->seq;
626 item = pqueue_find(s->d1->buffered_messages, seq64be);
630 frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
633 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
634 frag->msg_header.frag_len = frag->msg_header.msg_len;
635 frag->msg_header.frag_off = 0;
639 frag = (hm_fragment*) item->data;
640 if (frag->msg_header.msg_len != msg_hdr->msg_len)
649 /* If message is already reassembled, this must be a
650 * retransmit and can be dropped. In this case item != NULL and so frag
651 * does not need to be freed.
653 if (frag->reassembly == NULL)
655 unsigned char devnull [256];
659 i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
661 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
665 return DTLS1_HM_FRAGMENT_RETRY;
668 /* read the body of the fragment (header has already been read */
669 i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
670 frag->fragment + msg_hdr->frag_off,frag_len,0);
671 if ((unsigned long)i!=frag_len)
676 RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
677 (long)(msg_hdr->frag_off + frag_len));
679 RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
684 OPENSSL_free(frag->reassembly);
685 frag->reassembly = NULL;
690 memset(seq64be,0,sizeof(seq64be));
691 seq64be[6] = (unsigned char)(msg_hdr->seq>>8);
692 seq64be[7] = (unsigned char)(msg_hdr->seq);
694 item = pitem_new(seq64be, frag);
701 item = pqueue_insert(s->d1->buffered_messages, item);
702 /* pqueue_insert fails iff a duplicate item is inserted.
703 * However, |item| cannot be a duplicate. If it were,
704 * |pqueue_find|, above, would have returned it and control
705 * would never have reached this branch. */
706 OPENSSL_assert(item != NULL);
709 return DTLS1_HM_FRAGMENT_RETRY;
712 if (frag != NULL && item == NULL) dtls1_hm_fragment_free(frag);
719 dtls1_process_out_of_seq_message(SSL *s, struct hm_header_st* msg_hdr, int *ok)
722 hm_fragment *frag = NULL;
724 unsigned char seq64be[8];
725 unsigned long frag_len = msg_hdr->frag_len;
727 if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
730 /* Try to find item in queue, to prevent duplicate entries */
731 memset(seq64be,0,sizeof(seq64be));
732 seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
733 seq64be[7] = (unsigned char) msg_hdr->seq;
734 item = pqueue_find(s->d1->buffered_messages, seq64be);
736 /* If we already have an entry and this one is a fragment,
737 * don't discard it and rather try to reassemble it.
739 if (item != NULL && frag_len < msg_hdr->msg_len)
742 /* Discard the message if sequence number was already there, is
743 * too far in the future, already in the queue or if we received
744 * a FINISHED before the SERVER_HELLO, which then must be a stale
747 if (msg_hdr->seq <= s->d1->handshake_read_seq ||
748 msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
749 (s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED))
751 unsigned char devnull [256];
755 i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
757 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
764 if (frag_len < msg_hdr->msg_len)
765 return dtls1_reassemble_fragment(s, msg_hdr, ok);
767 if (frag_len > dtls1_max_handshake_message_len(s))
770 frag = dtls1_hm_fragment_new(frag_len, 0);
774 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
778 /* read the body of the fragment (header has already been read */
779 i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
780 frag->fragment,frag_len,0);
781 if ((unsigned long)i!=frag_len)
787 memset(seq64be,0,sizeof(seq64be));
788 seq64be[6] = (unsigned char)(msg_hdr->seq>>8);
789 seq64be[7] = (unsigned char)(msg_hdr->seq);
791 item = pitem_new(seq64be, frag);
795 item = pqueue_insert(s->d1->buffered_messages, item);
796 /* pqueue_insert fails iff a duplicate item is inserted.
797 * However, |item| cannot be a duplicate. If it were,
798 * |pqueue_find|, above, would have returned it. Then, either
799 * |frag_len| != |msg_hdr->msg_len| in which case |item| is set
800 * to NULL and it will have been processed with
801 * |dtls1_reassemble_fragment|, above, or the record will have
803 OPENSSL_assert(item != NULL);
806 return DTLS1_HM_FRAGMENT_RETRY;
809 if (frag != NULL && item == NULL) dtls1_hm_fragment_free(frag);
816 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
818 unsigned char wire[DTLS1_HM_HEADER_LENGTH];
819 unsigned long len, frag_off, frag_len;
821 struct hm_header_st msg_hdr;
824 /* see if we have the required fragment already */
825 if ((frag_len = dtls1_retrieve_buffered_fragment(s,max,ok)) || *ok)
827 if (*ok) s->init_num = frag_len;
831 /* read handshake message header */
832 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,wire,
833 DTLS1_HM_HEADER_LENGTH, 0);
834 if (i <= 0) /* nbio, or an error */
836 s->rwstate=SSL_READING;
840 /* Handshake fails if message header is incomplete */
841 if (i != DTLS1_HM_HEADER_LENGTH)
843 al=SSL_AD_UNEXPECTED_MESSAGE;
844 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
848 /* parse the message fragment header */
849 dtls1_get_message_header(wire, &msg_hdr);
852 * if this is a future (or stale) message it gets buffered
853 * (or dropped)--no further processing at this time
854 * While listening, we accept seq 1 (ClientHello with cookie)
855 * although we're still expecting seq 0 (ClientHello)
857 if (msg_hdr.seq != s->d1->handshake_read_seq && !(s->d1->listen && msg_hdr.seq == 1))
858 return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
860 len = msg_hdr.msg_len;
861 frag_off = msg_hdr.frag_off;
862 frag_len = msg_hdr.frag_len;
864 if (frag_len && frag_len < len)
865 return dtls1_reassemble_fragment(s, &msg_hdr, ok);
867 if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
868 wire[0] == SSL3_MT_HELLO_REQUEST)
870 /* The server may always send 'Hello Request' messages --
871 * we are doing a handshake anyway now, so ignore them
872 * if their format is correct. Does not count for
874 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0)
877 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
878 wire, DTLS1_HM_HEADER_LENGTH, s,
879 s->msg_callback_arg);
884 else /* Incorrectly formated Hello request */
886 al=SSL_AD_UNEXPECTED_MESSAGE;
887 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
892 if ((al=dtls1_preprocess_fragment(s,&msg_hdr,max)))
895 /* XDTLS: ressurect this when restart is in place */
900 unsigned char *p=(unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
902 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
903 &p[frag_off],frag_len,0);
904 /* XDTLS: fix this--message fragments cannot span multiple packets */
907 s->rwstate=SSL_READING;
915 /* XDTLS: an incorrectly formatted fragment should cause the
916 * handshake to fail */
917 if (i != (int)frag_len)
919 al=SSL3_AD_ILLEGAL_PARAMETER;
920 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL3_AD_ILLEGAL_PARAMETER);
926 /* Note that s->init_num is *not* used as current offset in
927 * s->init_buf->data, but as a counter summing up fragments'
928 * lengths: as soon as they sum up to handshake packet
929 * length, we assume we have got all the fragments. */
930 s->init_num = frag_len;
934 ssl3_send_alert(s,SSL3_AL_FATAL,al);
941 /* for these 2 messages, we need to
942 * ssl->enc_read_ctx re-init
943 * ssl->s3->read_sequence zero
944 * ssl->s3->read_mac_secret re-init
945 * ssl->session->read_sym_enc assign
946 * ssl->session->read_compression assign
947 * ssl->session->read_hash assign
949 int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
955 p=(unsigned char *)s->init_buf->data;
957 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
958 s->init_num=DTLS1_CCS_HEADER_LENGTH;
960 if (s->version == DTLS1_BAD_VER) {
961 s->d1->next_handshake_write_seq++;
962 s2n(s->d1->handshake_write_seq,p);
968 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
969 s->d1->handshake_write_seq, 0, 0);
971 /* buffer the message to handle re-xmits */
972 dtls1_buffer_message(s, 1);
977 /* SSL3_ST_CW_CHANGE_B */
978 return(dtls1_do_write(s,SSL3_RT_CHANGE_CIPHER_SPEC));
981 int dtls1_read_failed(SSL *s, int code)
985 fprintf( stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
989 if (!dtls1_is_timer_expired(s))
991 /* not a timeout, none of our business,
992 let higher layers handle this. in fact it's probably an error */
996 #ifndef OPENSSL_NO_HEARTBEATS
997 if (!SSL_in_init(s) && !s->tlsext_hb_pending) /* done, no need to send a retransmit */
999 if (!SSL_in_init(s)) /* done, no need to send a retransmit */
1002 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
1006 #if 0 /* for now, each alert contains only one record number */
1007 item = pqueue_peek(state->rcvd_records);
1010 /* send an alert immediately for all the missing records */
1015 #if 0 /* no more alert sending, just retransmit the last set of messages */
1016 if ( state->timeout.read_timeouts >= DTLS1_TMO_READ_COUNT)
1017 ssl3_send_alert(s,SSL3_AL_WARNING,
1018 DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
1021 return dtls1_handle_timeout(s);
1025 dtls1_get_queue_priority(unsigned short seq, int is_ccs)
1027 /* The index of the retransmission queue actually is the message sequence number,
1028 * since the queue only contains messages of a single handshake. However, the
1029 * ChangeCipherSpec has no message sequence number and so using only the sequence
1030 * will result in the CCS and Finished having the same index. To prevent this,
1031 * the sequence number is multiplied by 2. In case of a CCS 1 is subtracted.
1032 * This does not only differ CSS and Finished, it also maintains the order of the
1033 * index (important for priority queues) and fits in the unsigned short variable.
1035 return seq * 2 - is_ccs;
1039 dtls1_retransmit_buffered_messages(SSL *s)
1041 pqueue sent = s->d1->sent_messages;
1047 iter = pqueue_iterator(sent);
1049 for ( item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter))
1051 frag = (hm_fragment *)item->data;
1052 if ( dtls1_retransmit_message(s,
1053 (unsigned short)dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs),
1054 0, &found) <= 0 && found)
1056 fprintf(stderr, "dtls1_retransmit_message() failed\n");
1065 dtls1_buffer_message(SSL *s, int is_ccs)
1069 unsigned char seq64be[8];
1071 /* this function is called immediately after a message has
1072 * been serialized */
1073 OPENSSL_assert(s->init_off == 0);
1075 frag = dtls1_hm_fragment_new(s->init_num, 0);
1079 memcpy(frag->fragment, s->init_buf->data, s->init_num);
1083 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1084 DTLS1_CCS_HEADER_LENGTH == (unsigned int)s->init_num);
1088 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1089 DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
1092 frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1093 frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1094 frag->msg_header.type = s->d1->w_msg_hdr.type;
1095 frag->msg_header.frag_off = 0;
1096 frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1097 frag->msg_header.is_ccs = is_ccs;
1099 /* save current state*/
1100 frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
1101 frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
1102 frag->msg_header.saved_retransmit_state.compress = s->compress;
1103 frag->msg_header.saved_retransmit_state.session = s->session;
1104 frag->msg_header.saved_retransmit_state.epoch = s->d1->w_epoch;
1106 memset(seq64be,0,sizeof(seq64be));
1107 seq64be[6] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1108 frag->msg_header.is_ccs)>>8);
1109 seq64be[7] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1110 frag->msg_header.is_ccs));
1112 item = pitem_new(seq64be, frag);
1115 dtls1_hm_fragment_free(frag);
1120 fprintf( stderr, "buffered messge: \ttype = %xx\n", msg_buf->type);
1121 fprintf( stderr, "\t\t\t\t\tlen = %d\n", msg_buf->len);
1122 fprintf( stderr, "\t\t\t\t\tseq_num = %d\n", msg_buf->seq_num);
1125 pqueue_insert(s->d1->sent_messages, item);
1130 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
1134 /* XDTLS: for now assuming that read/writes are blocking */
1137 unsigned long header_length;
1138 unsigned char seq64be[8];
1139 struct dtls1_retransmit_state saved_state;
1140 unsigned char save_write_sequence[8];
1143 OPENSSL_assert(s->init_num == 0);
1144 OPENSSL_assert(s->init_off == 0);
1147 /* XDTLS: the requested message ought to be found, otherwise error */
1148 memset(seq64be,0,sizeof(seq64be));
1149 seq64be[6] = (unsigned char)(seq>>8);
1150 seq64be[7] = (unsigned char)seq;
1152 item = pqueue_find(s->d1->sent_messages, seq64be);
1155 fprintf(stderr, "retransmit: message %d non-existant\n", seq);
1161 frag = (hm_fragment *)item->data;
1163 if ( frag->msg_header.is_ccs)
1164 header_length = DTLS1_CCS_HEADER_LENGTH;
1166 header_length = DTLS1_HM_HEADER_LENGTH;
1168 memcpy(s->init_buf->data, frag->fragment,
1169 frag->msg_header.msg_len + header_length);
1170 s->init_num = frag->msg_header.msg_len + header_length;
1172 dtls1_set_message_header_int(s, frag->msg_header.type,
1173 frag->msg_header.msg_len, frag->msg_header.seq, 0,
1174 frag->msg_header.frag_len);
1176 /* save current state */
1177 saved_state.enc_write_ctx = s->enc_write_ctx;
1178 saved_state.write_hash = s->write_hash;
1179 saved_state.compress = s->compress;
1180 saved_state.session = s->session;
1181 saved_state.epoch = s->d1->w_epoch;
1182 saved_state.epoch = s->d1->w_epoch;
1184 s->d1->retransmitting = 1;
1186 /* restore state in which the message was originally sent */
1187 s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
1188 s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
1189 s->compress = frag->msg_header.saved_retransmit_state.compress;
1190 s->session = frag->msg_header.saved_retransmit_state.session;
1191 s->d1->w_epoch = frag->msg_header.saved_retransmit_state.epoch;
1193 if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1195 memcpy(save_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1196 memcpy(s->s3->write_sequence, s->d1->last_write_sequence, sizeof(s->s3->write_sequence));
1199 ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1200 SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1202 /* restore current state */
1203 s->enc_write_ctx = saved_state.enc_write_ctx;
1204 s->write_hash = saved_state.write_hash;
1205 s->compress = saved_state.compress;
1206 s->session = saved_state.session;
1207 s->d1->w_epoch = saved_state.epoch;
1209 if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1211 memcpy(s->d1->last_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1212 memcpy(s->s3->write_sequence, save_write_sequence, sizeof(s->s3->write_sequence));
1215 s->d1->retransmitting = 0;
1217 (void)BIO_flush(SSL_get_wbio(s));
1221 /* call this function when the buffered messages are no longer needed */
1223 dtls1_clear_record_buffer(SSL *s)
1227 for(item = pqueue_pop(s->d1->sent_messages);
1228 item != NULL; item = pqueue_pop(s->d1->sent_messages))
1230 dtls1_hm_fragment_free((hm_fragment *)item->data);
1237 dtls1_set_message_header(SSL *s, unsigned char *p, unsigned char mt,
1238 unsigned long len, unsigned long frag_off, unsigned long frag_len)
1240 /* Don't change sequence numbers while listening */
1241 if (frag_off == 0 && !s->d1->listen)
1243 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1244 s->d1->next_handshake_write_seq++;
1247 dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1248 frag_off, frag_len);
1250 return p += DTLS1_HM_HEADER_LENGTH;
1254 /* don't actually do the writing, wait till the MTU has been retrieved */
1256 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1257 unsigned long len, unsigned short seq_num, unsigned long frag_off,
1258 unsigned long frag_len)
1260 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1263 msg_hdr->msg_len = len;
1264 msg_hdr->seq = seq_num;
1265 msg_hdr->frag_off = frag_off;
1266 msg_hdr->frag_len = frag_len;
1270 dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1271 unsigned long frag_len)
1273 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1275 msg_hdr->frag_off = frag_off;
1276 msg_hdr->frag_len = frag_len;
1279 static unsigned char *
1280 dtls1_write_message_header(SSL *s, unsigned char *p)
1282 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1284 *p++ = msg_hdr->type;
1285 l2n3(msg_hdr->msg_len, p);
1287 s2n(msg_hdr->seq, p);
1288 l2n3(msg_hdr->frag_off, p);
1289 l2n3(msg_hdr->frag_len, p);
1297 return (g_probable_mtu[(sizeof(g_probable_mtu) /
1298 sizeof(g_probable_mtu[0])) - 1]);
1302 dtls1_guess_mtu(unsigned int curr_mtu)
1306 if ( curr_mtu == 0 )
1307 return g_probable_mtu[0] ;
1309 for ( i = 0; i < sizeof(g_probable_mtu)/sizeof(g_probable_mtu[0]); i++)
1310 if ( curr_mtu > g_probable_mtu[i])
1311 return g_probable_mtu[i];
1317 dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1319 memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
1320 msg_hdr->type = *(data++);
1321 n2l3(data, msg_hdr->msg_len);
1323 n2s(data, msg_hdr->seq);
1324 n2l3(data, msg_hdr->frag_off);
1325 n2l3(data, msg_hdr->frag_len);
1329 dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
1331 memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
1333 ccs_hdr->type = *(data++);
1336 int dtls1_shutdown(SSL *s)
1339 #ifndef OPENSSL_NO_SCTP
1340 if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
1341 !(s->shutdown & SSL_SENT_SHUTDOWN))
1343 ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
1344 if (ret < 0) return -1;
1347 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1, NULL);
1350 ret = ssl3_shutdown(s);
1351 #ifndef OPENSSL_NO_SCTP
1352 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
1357 #ifndef OPENSSL_NO_HEARTBEATS
1359 dtls1_process_heartbeat(SSL *s)
1361 unsigned char *p = &s->s3->rrec.data[0], *pl;
1362 unsigned short hbtype;
1363 unsigned int payload;
1364 unsigned int padding = 16; /* Use minimum padding */
1366 if (s->msg_callback)
1367 s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
1368 &s->s3->rrec.data[0], s->s3->rrec.length,
1369 s, s->msg_callback_arg);
1371 /* Read type and payload length first */
1372 if (1 + 2 + 16 > s->s3->rrec.length)
1373 return 0; /* silently discard */
1376 if (1 + 2 + payload + 16 > s->s3->rrec.length)
1377 return 0; /* silently discard per RFC 6520 sec. 4 */
1380 if (hbtype == TLS1_HB_REQUEST)
1382 unsigned char *buffer, *bp;
1383 unsigned int write_length = 1 /* heartbeat type */ +
1384 2 /* heartbeat length */ +
1388 if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
1391 /* Allocate memory for the response, size is 1 byte
1392 * message type, plus 2 bytes payload length, plus
1393 * payload, plus padding
1395 buffer = OPENSSL_malloc(write_length);
1398 /* Enter response type, length and copy payload */
1399 *bp++ = TLS1_HB_RESPONSE;
1401 memcpy(bp, pl, payload);
1403 /* Random padding */
1404 RAND_pseudo_bytes(bp, padding);
1406 r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
1408 if (r >= 0 && s->msg_callback)
1409 s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1410 buffer, write_length,
1411 s, s->msg_callback_arg);
1413 OPENSSL_free(buffer);
1418 else if (hbtype == TLS1_HB_RESPONSE)
1422 /* We only send sequence numbers (2 bytes unsigned int),
1423 * and 16 random bytes, so we just try to read the
1424 * sequence number */
1427 if (payload == 18 && seq == s->tlsext_hb_seq)
1429 dtls1_stop_timer(s);
1431 s->tlsext_hb_pending = 0;
1439 dtls1_heartbeat(SSL *s)
1441 unsigned char *buf, *p;
1443 unsigned int payload = 18; /* Sequence number + random bytes */
1444 unsigned int padding = 16; /* Use minimum padding */
1446 /* Only send if peer supports and accepts HB requests... */
1447 if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
1448 s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS)
1450 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
1454 /* ...and there is none in flight yet... */
1455 if (s->tlsext_hb_pending)
1457 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PENDING);
1461 /* ...and no handshake in progress. */
1462 if (SSL_in_init(s) || s->in_handshake)
1464 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_UNEXPECTED_MESSAGE);
1468 /* Check if padding is too long, payload and padding
1469 * must not exceed 2^14 - 3 = 16381 bytes in total.
1471 OPENSSL_assert(payload + padding <= 16381);
1473 /* Create HeartBeat message, we just use a sequence number
1474 * as payload to distuingish different messages and add
1475 * some random stuff.
1476 * - Message Type, 1 byte
1477 * - Payload Length, 2 bytes (unsigned int)
1478 * - Payload, the sequence number (2 bytes uint)
1479 * - Payload, random bytes (16 bytes uint)
1482 buf = OPENSSL_malloc(1 + 2 + payload + padding);
1485 *p++ = TLS1_HB_REQUEST;
1486 /* Payload length (18 bytes here) */
1488 /* Sequence number */
1489 s2n(s->tlsext_hb_seq, p);
1490 /* 16 random bytes */
1491 RAND_pseudo_bytes(p, 16);
1493 /* Random padding */
1494 RAND_pseudo_bytes(p, padding);
1496 ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
1499 if (s->msg_callback)
1500 s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1501 buf, 3 + payload + padding,
1502 s, s->msg_callback_arg);
1504 dtls1_start_timer(s);
1505 s->tlsext_hb_pending = 1;