ssl/d1_both.c

   1 /* ssl/d1_both.c */
   2 /*
   3  * DTLS implementation written by Nagendra Modadugu
   4  * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
   5  */
   6 /* ====================================================================
   7  * Copyright (c) 1998-2005 The OpenSSL Project.  All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  *
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  *
  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
  19  *    distribution.
  20  *
  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/)"
  25  *
  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.
  30  *
  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.
  34  *
  35  * 6. Redistributions of any form whatsoever must retain the following
  36  *    acknowledgment:
  37  *    "This product includes software developed by the OpenSSL Project
  38  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  39  *
  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  * ====================================================================
  53  *
  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).
  57  *
  58  */
  59 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  60  * All rights reserved.
  61  *
  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.
  65  *
  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).
  72  *
  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.
  79  *
  80  * Redistribution and use in source and binary forms, with or without
  81  * modification, are permitted provided that the following conditions
  82  * are met:
  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)"
  97  *
  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
 108  * SUCH DAMAGE.
 109  *
 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.]
 114  */
 115
 116 #include <limits.h>
 117 #include <string.h>
 118 #include <stdio.h>
 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>
 125
 126 #define RSMBLY_BITMASK_SIZE(msg_len) (((msg_len) + 7) / 8)
 127
 128 #define RSMBLY_BITMASK_MARK(bitmask, start, end) { \
 129                         if ((end) - (start) <= 8) { \
 130                                 long ii; \
 131                                 for (ii = (start); ii < (end); ii++) bitmask[((ii) >> 3)] |= (1 << ((ii) & 7)); \
 132                         } else { \
 133                                 long ii; \
 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)]; \
 137                         } }
 138
 139 #define RSMBLY_BITMASK_IS_COMPLETE(bitmask, msg_len, is_complete) { \
 140                         long ii; \
 141                         OPENSSL_assert((msg_len) > 0); \
 142                         is_complete = 1; \
 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; } }
 146
 147 #if 0
 148 #define RSMBLY_BITMASK_PRINT(bitmask, msg_len) { \
 149                         long ii; \
 150                         printf("bitmask: "); for (ii = 0; ii < (msg_len); ii++) \
 151                         printf("%d ", (bitmask[ii >> 3] & (1 << (ii & 7))) >> (ii & 7)); \
 152                         printf("\n"); }
 153 #endif
 154
 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};
 157
 158 /* XDTLS:  figure out the right values */
 159 static unsigned int g_probable_mtu[] = {1500 - 28, 512 - 28, 256 - 28};
 160
 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,
 165         unsigned char *p);
 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,
 170         long max, int *ok);
 171
 172 static hm_fragment *
 173 dtls1_hm_fragment_new(unsigned long frag_len, int reassembly)
 174         {
 175         hm_fragment *frag = NULL;
 176         unsigned char *buf = NULL;
 177         unsigned char *bitmask = NULL;
 178
 179         frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment));
 180         if ( frag == NULL)
 181                 return NULL;
 182
 183         if (frag_len)
 184                 {
 185                 buf = (unsigned char *)OPENSSL_malloc(frag_len);
 186                 if ( buf == NULL)
 187                         {
 188                         OPENSSL_free(frag);
 189                         return NULL;
 190                         }
 191                 }
 192
 193         /* zero length fragment gets zero frag->fragment */
 194         frag->fragment = buf;
 195
 196         /* Initialize reassembly bitmask if necessary */
 197         if (reassembly)
 198                 {
 199                 bitmask = (unsigned char *)OPENSSL_malloc(RSMBLY_BITMASK_SIZE(frag_len));
 200                 if (bitmask == NULL)
 201                         {
 202                         if (buf != NULL) OPENSSL_free(buf);
 203                         OPENSSL_free(frag);
 204                         return NULL;
 205                         }
 206                 memset(bitmask, 0, RSMBLY_BITMASK_SIZE(frag_len));
 207                 }
 208
 209         frag->reassembly = bitmask;
 210
 211         return frag;
 212         }
 213
 214 static void
 215 dtls1_hm_fragment_free(hm_fragment *frag)
 216         {
 217         if (frag->fragment) OPENSSL_free(frag->fragment);
 218         if (frag->reassembly) OPENSSL_free(frag->reassembly);
 219         OPENSSL_free(frag);
 220         }
 221
 222 /* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
 223 int dtls1_do_write(SSL *s, int type)
 224         {
 225         int ret;
 226         int curr_mtu;
 227         unsigned int len, frag_off, mac_size, blocksize;
 228
 229         /* AHA!  Figure out the MTU, and stick to the right size */
 230         if (s->d1->mtu < dtls1_min_mtu() && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
 231                 {
 232                 s->d1->mtu =
 233                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
 234
 235                 /* I've seen the kernel return bogus numbers when it doesn't know
 236                  * (initial write), so just make sure we have a reasonable number */
 237                 if (s->d1->mtu < dtls1_min_mtu())
 238                         {
 239                         s->d1->mtu = 0;
 240                         s->d1->mtu = dtls1_guess_mtu(s->d1->mtu);
 241                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
 242                                 s->d1->mtu, NULL);
 243                         }
 244                 }
 245 #if 0
 246         mtu = s->d1->mtu;
 247
 248         fprintf(stderr, "using MTU = %d\n", mtu);
 249
 250         mtu -= (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 251
 252         curr_mtu = mtu - BIO_wpending(SSL_get_wbio(s));
 253
 254         if ( curr_mtu > 0)
 255                 mtu = curr_mtu;
 256         else if ( ( ret = BIO_flush(SSL_get_wbio(s))) <= 0)
 257                 return ret;
 258
 259         if ( BIO_wpending(SSL_get_wbio(s)) + s->init_num >= mtu)
 260                 {
 261                 ret = BIO_flush(SSL_get_wbio(s));
 262                 if ( ret <= 0)
 263                         return ret;
 264                 mtu = s->d1->mtu - (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 265                 }
 266 #endif
 267
 268         OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu());  /* should have something reasonable now */
 269
 270         if ( s->init_off == 0  && type == SSL3_RT_HANDSHAKE)
 271                 OPENSSL_assert(s->init_num ==
 272                         (int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH);
 273
 274         if (s->write_hash)
 275                 {
 276                 if (s->enc_write_ctx && EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_GCM_MODE)
 277                         mac_size = 0;
 278                 else
 279                         mac_size = EVP_MD_CTX_size(s->write_hash);
 280                 }
 281         else
 282                 mac_size = 0;
 283
 284         if (s->enc_write_ctx &&
 285                 (EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_CBC_MODE))
 286                 blocksize = 2 * EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
 287         else
 288                 blocksize = 0;
 289
 290         frag_off = 0;
 291         while( s->init_num)
 292                 {
 293                 curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) -
 294                         DTLS1_RT_HEADER_LENGTH - mac_size - blocksize;
 295
 296                 if ( curr_mtu <= DTLS1_HM_HEADER_LENGTH)
 297                         {
 298                         /* grr.. we could get an error if MTU picked was wrong */
 299                         ret = BIO_flush(SSL_get_wbio(s));
 300                         if ( ret <= 0)
 301                                 return ret;
 302                         curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH -
 303                                 mac_size - blocksize;
 304                         }
 305
 306                 if ( s->init_num > curr_mtu)
 307                         len = curr_mtu;
 308                 else
 309                         len = s->init_num;
 310
 311
 312                 /* XDTLS: this function is too long.  split out the CCS part */
 313                 if ( type == SSL3_RT_HANDSHAKE)
 314                         {
 315                         if ( s->init_off != 0)
 316                                 {
 317                                 OPENSSL_assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
 318                                 s->init_off -= DTLS1_HM_HEADER_LENGTH;
 319                                 s->init_num += DTLS1_HM_HEADER_LENGTH;
 320
 321                                 if ( s->init_num > curr_mtu)
 322                                         len = curr_mtu;
 323                                 else
 324                                         len = s->init_num;
 325                                 }
 326
 327                         dtls1_fix_message_header(s, frag_off,
 328                                 len - DTLS1_HM_HEADER_LENGTH);
 329
 330                         dtls1_write_message_header(s, (unsigned char *)&s->init_buf->data[s->init_off]);
 331
 332                         OPENSSL_assert(len >= DTLS1_HM_HEADER_LENGTH);
 333                         }
 334
 335                 ret=dtls1_write_bytes(s,type,&s->init_buf->data[s->init_off],
 336                         len);
 337                 if (ret < 0)
 338                         {
 339                         /* might need to update MTU here, but we don't know
 340                          * which previous packet caused the failure -- so can't
 341                          * really retransmit anything.  continue as if everything
 342                          * is fine and wait for an alert to handle the
 343                          * retransmit
 344                          */
 345                         if ( BIO_ctrl(SSL_get_wbio(s),
 346                                 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0 )
 347                                 s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
 348                                         BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
 349                         else
 350                                 return(-1);
 351                         }
 352                 else
 353                         {
 354
 355                         /* bad if this assert fails, only part of the handshake
 356                          * message got sent.  but why would this happen? */
 357                         OPENSSL_assert(len == (unsigned int)ret);
 358
 359                         if (type == SSL3_RT_HANDSHAKE && ! s->d1->retransmitting)
 360                                 {
 361                                 /* should not be done for 'Hello Request's, but in that case
 362                                  * we'll ignore the result anyway */
 363                                 unsigned char *p = (unsigned char *)&s->init_buf->data[s->init_off];
 364                                 const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
 365                                 int xlen;
 366
 367                                 if (frag_off == 0 && s->version != DTLS1_BAD_VER)
 368                                         {
 369                                         /* reconstruct message header is if it
 370                                          * is being sent in single fragment */
 371                                         *p++ = msg_hdr->type;
 372                                         l2n3(msg_hdr->msg_len,p);
 373                                         s2n (msg_hdr->seq,p);
 374                                         l2n3(0,p);
 375                                         l2n3(msg_hdr->msg_len,p);
 376                                         p  -= DTLS1_HM_HEADER_LENGTH;
 377                                         xlen = ret;
 378                                         }
 379                                 else
 380                                         {
 381                                         p  += DTLS1_HM_HEADER_LENGTH;
 382                                         xlen = ret - DTLS1_HM_HEADER_LENGTH;
 383                                         }
 384
 385                                 ssl3_finish_mac(s, p, xlen);
 386                                 }
 387
 388                         if (ret == s->init_num)
 389                                 {
 390                                 if (s->msg_callback)
 391                                         s->msg_callback(1, s->version, type, s->init_buf->data,
 392                                                 (size_t)(s->init_off + s->init_num), s,
 393                                                 s->msg_callback_arg);
 394
 395                                 s->init_off = 0;  /* done writing this message */
 396                                 s->init_num = 0;
 397
 398                                 return(1);
 399                                 }
 400                         s->init_off+=ret;
 401                         s->init_num-=ret;
 402                         frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
 403                         }
 404                 }
 405         return(0);
 406         }
 407
 408
 409 /* Obtain handshake message of message type 'mt' (any if mt == -1),
 410  * maximum acceptable body length 'max'.
 411  * Read an entire handshake message.  Handshake messages arrive in
 412  * fragments.
 413  */
 414 long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
 415         {
 416         int i, al;
 417         struct hm_header_st *msg_hdr;
 418         unsigned char *p;
 419         unsigned long msg_len;
 420
 421         /* s3->tmp is used to store messages that are unexpected, caused
 422          * by the absence of an optional handshake message */
 423         if (s->s3->tmp.reuse_message)
 424                 {
 425                 s->s3->tmp.reuse_message=0;
 426                 if ((mt >= 0) && (s->s3->tmp.message_type != mt))
 427                         {
 428                         al=SSL_AD_UNEXPECTED_MESSAGE;
 429                         SSLerr(SSL_F_DTLS1_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
 430                         goto f_err;
 431                         }
 432                 *ok=1;
 433                 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 434                 s->init_num = (int)s->s3->tmp.message_size;
 435                 return s->init_num;
 436                 }
 437
 438         msg_hdr = &s->d1->r_msg_hdr;
 439         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 440
 441 again:
 442         i = dtls1_get_message_fragment(s, st1, stn, max, ok);
 443         if ( i == DTLS1_HM_BAD_FRAGMENT ||
 444                 i == DTLS1_HM_FRAGMENT_RETRY)  /* bad fragment received */
 445                 goto again;
 446         else if ( i <= 0 && !*ok)
 447                 return i;
 448
 449         p = (unsigned char *)s->init_buf->data;
 450         msg_len = msg_hdr->msg_len;
 451
 452         /* reconstruct message header */
 453         *(p++) = msg_hdr->type;
 454         l2n3(msg_len,p);
 455         s2n (msg_hdr->seq,p);
 456         l2n3(0,p);
 457         l2n3(msg_len,p);
 458         if (s->version != DTLS1_BAD_VER) {
 459                 p       -= DTLS1_HM_HEADER_LENGTH;
 460                 msg_len += DTLS1_HM_HEADER_LENGTH;
 461         }
 462
 463         ssl3_finish_mac(s, p, msg_len);
 464         if (s->msg_callback)
 465                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 466                         p, msg_len,
 467                         s, s->msg_callback_arg);
 468
 469         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 470
 471         /* Don't change sequence numbers while listening */
 472         if (!s->d1->listen)
 473                 s->d1->handshake_read_seq++;
 474
 475         s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 476         return s->init_num;
 477
 478 f_err:
 479         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 480         *ok = 0;
 481         return -1;
 482         }
 483
 484
 485 static int dtls1_preprocess_fragment(SSL *s,struct hm_header_st *msg_hdr,int max)
 486         {
 487         size_t frag_off,frag_len,msg_len;
 488
 489         msg_len  = msg_hdr->msg_len;
 490         frag_off = msg_hdr->frag_off;
 491         frag_len = msg_hdr->frag_len;
 492
 493         /* sanity checking */
 494         if ( (frag_off+frag_len) > msg_len)
 495                 {
 496                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 497                 return SSL_AD_ILLEGAL_PARAMETER;
 498                 }
 499
 500         if ( (frag_off+frag_len) > (unsigned long)max)
 501                 {
 502                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 503                 return SSL_AD_ILLEGAL_PARAMETER;
 504                 }
 505
 506         if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */
 507                 {
 508                 /* msg_len is limited to 2^24, but is effectively checked
 509                  * against max above */
 510                 if (!BUF_MEM_grow_clean(s->init_buf,msg_len+DTLS1_HM_HEADER_LENGTH))
 511                         {
 512                         SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,ERR_R_BUF_LIB);
 513                         return SSL_AD_INTERNAL_ERROR;
 514                         }
 515
 516                 s->s3->tmp.message_size  = msg_len;
 517                 s->d1->r_msg_hdr.msg_len = msg_len;
 518                 s->s3->tmp.message_type  = msg_hdr->type;
 519                 s->d1->r_msg_hdr.type    = msg_hdr->type;
 520                 s->d1->r_msg_hdr.seq     = msg_hdr->seq;
 521                 }
 522         else if (msg_len != s->d1->r_msg_hdr.msg_len)
 523                 {
 524                 /* They must be playing with us! BTW, failure to enforce
 525                  * upper limit would open possibility for buffer overrun. */
 526                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 527                 return SSL_AD_ILLEGAL_PARAMETER;
 528                 }
 529
 530         return 0; /* no error */
 531         }
 532
 533
 534 static int
 535 dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok)
 536         {
 537         /* (0) check whether the desired fragment is available
 538          * if so:
 539          * (1) copy over the fragment to s->init_buf->data[]
 540          * (2) update s->init_num
 541          */
 542         pitem *item;
 543         hm_fragment *frag;
 544         int al;
 545
 546         *ok = 0;
 547         item = pqueue_peek(s->d1->buffered_messages);
 548         if ( item == NULL)
 549                 return 0;
 550
 551         frag = (hm_fragment *)item->data;
 552
 553         /* Don't return if reassembly still in progress */
 554         if (frag->reassembly != NULL)
 555                 return 0;
 556
 557         if ( s->d1->handshake_read_seq == frag->msg_header.seq)
 558                 {
 559                 unsigned long frag_len = frag->msg_header.frag_len;
 560                 pqueue_pop(s->d1->buffered_messages);
 561
 562                 al=dtls1_preprocess_fragment(s,&frag->msg_header,max);
 563
 564                 if (al==0) /* no alert */
 565                         {
 566                         unsigned char *p = (unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 567                         memcpy(&p[frag->msg_header.frag_off],
 568                                 frag->fragment,frag->msg_header.frag_len);
 569                         }
 570
 571                 dtls1_hm_fragment_free(frag);
 572                 pitem_free(item);
 573
 574                 if (al==0)
 575                         {
 576                         *ok = 1;
 577                         return frag_len;
 578                         }
 579
 580                 ssl3_send_alert(s,SSL3_AL_FATAL,al);
 581                 s->init_num = 0;
 582                 *ok = 0;
 583                 return -1;
 584                 }
 585         else
 586                 return 0;
 587         }
 588
 589
 590 static int
 591 dtls1_reassemble_fragment(SSL *s, struct hm_header_st* msg_hdr, int *ok)
 592         {
 593         hm_fragment *frag = NULL;
 594         pitem *item = NULL;
 595         int i = -1, is_complete;
 596         unsigned char seq64be[8];
 597         unsigned long frag_len = msg_hdr->frag_len, max_len;
 598
 599         if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
 600                 goto err;
 601
 602         /* Determine maximum allowed message size. Depends on (user set)
 603          * maximum certificate length, but 16k is minimum.
 604          */
 605         if (DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH < s->max_cert_list)
 606                 max_len = s->max_cert_list;
 607         else
 608                 max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
 609
 610         if ((msg_hdr->frag_off+frag_len) > max_len)
 611                 goto err;
 612
 613         /* Try to find item in queue */
 614         memset(seq64be,0,sizeof(seq64be));
 615         seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
 616         seq64be[7] = (unsigned char) msg_hdr->seq;
 617         item = pqueue_find(s->d1->buffered_messages, seq64be);
 618
 619         if (item == NULL)
 620                 {
 621                 frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
 622                 if ( frag == NULL)
 623                         goto err;
 624                 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 625                 frag->msg_header.frag_len = frag->msg_header.msg_len;
 626                 frag->msg_header.frag_off = 0;
 627                 }
 628         else
 629                 frag = (hm_fragment*) item->data;
 630
 631         /* If message is already reassembled, this must be a
 632          * retransmit and can be dropped.
 633          */
 634         if (frag->reassembly == NULL)
 635                 {
 636                 unsigned char devnull [256];
 637
 638                 while (frag_len)
 639                         {
 640                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 641                                 devnull,
 642                                 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
 643                         if (i<=0) goto err;
 644                         frag_len -= i;
 645                         }
 646                 return DTLS1_HM_FRAGMENT_RETRY;
 647                 }
 648
 649         /* read the body of the fragment (header has already been read */
 650         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 651                 frag->fragment + msg_hdr->frag_off,frag_len,0);
 652         if (i<=0 || (unsigned long)i!=frag_len)
 653                 goto err;
 654
 655         RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
 656                             (long)(msg_hdr->frag_off + frag_len));
 657
 658         RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
 659                                    is_complete);
 660
 661         if (is_complete)
 662                 {
 663                 OPENSSL_free(frag->reassembly);
 664                 frag->reassembly = NULL;
 665                 }
 666
 667         if (item == NULL)
 668                 {
 669                 memset(seq64be,0,sizeof(seq64be));
 670                 seq64be[6] = (unsigned char)(msg_hdr->seq>>8);
 671                 seq64be[7] = (unsigned char)(msg_hdr->seq);
 672
 673                 item = pitem_new(seq64be, frag);
 674                 if (item == NULL)
 675                         {
 676                         goto err;
 677                         i = -1;
 678                         }
 679
 680                 pqueue_insert(s->d1->buffered_messages, item);
 681                 }
 682
 683         return DTLS1_HM_FRAGMENT_RETRY;
 684
 685 err:
 686         if (frag != NULL) dtls1_hm_fragment_free(frag);
 687         if (item != NULL) OPENSSL_free(item);
 688         *ok = 0;
 689         return i;
 690         }
 691
 692
 693 static int
 694 dtls1_process_out_of_seq_message(SSL *s, struct hm_header_st* msg_hdr, int *ok)
 695 {
 696         int i=-1;
 697         hm_fragment *frag = NULL;
 698         pitem *item = NULL;
 699         unsigned char seq64be[8];
 700         unsigned long frag_len = msg_hdr->frag_len;
 701
 702         if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
 703                 goto err;
 704
 705         /* Try to find item in queue, to prevent duplicate entries */
 706         memset(seq64be,0,sizeof(seq64be));
 707         seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
 708         seq64be[7] = (unsigned char) msg_hdr->seq;
 709         item = pqueue_find(s->d1->buffered_messages, seq64be);
 710
 711         /* If we already have an entry and this one is a fragment,
 712          * don't discard it and rather try to reassemble it.
 713          */
 714         if (item != NULL && frag_len < msg_hdr->msg_len)
 715                 item = NULL;
 716
 717         /* Discard the message if sequence number was already there, is
 718          * too far in the future, already in the queue or if we received
 719          * a FINISHED before the SERVER_HELLO, which then must be a stale
 720          * retransmit.
 721          */
 722         if (msg_hdr->seq <= s->d1->handshake_read_seq ||
 723                 msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
 724                 (s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED))
 725                 {
 726                 unsigned char devnull [256];
 727
 728                 while (frag_len)
 729                         {
 730                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 731                                 devnull,
 732                                 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
 733                         if (i<=0) goto err;
 734                         frag_len -= i;
 735                         }
 736                 }
 737         else
 738                 {
 739                 if (frag_len && frag_len < msg_hdr->msg_len)
 740                         return dtls1_reassemble_fragment(s, msg_hdr, ok);
 741
 742                 frag = dtls1_hm_fragment_new(frag_len, 0);
 743                 if ( frag == NULL)
 744                         goto err;
 745
 746                 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 747
 748                 if (frag_len)
 749                         {
 750                         /* read the body of the fragment (header has already been read */
 751                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 752                                 frag->fragment,frag_len,0);
 753                         if (i<=0 || (unsigned long)i!=frag_len)
 754                                 goto err;
 755                         }
 756
 757                 memset(seq64be,0,sizeof(seq64be));
 758                 seq64be[6] = (unsigned char)(msg_hdr->seq>>8);
 759                 seq64be[7] = (unsigned char)(msg_hdr->seq);
 760
 761                 item = pitem_new(seq64be, frag);
 762                 if ( item == NULL)
 763                         goto err;
 764
 765                 pqueue_insert(s->d1->buffered_messages, item);
 766                 }
 767
 768         return DTLS1_HM_FRAGMENT_RETRY;
 769
 770 err:
 771         if ( frag != NULL) dtls1_hm_fragment_free(frag);
 772         if ( item != NULL) OPENSSL_free(item);
 773         *ok = 0;
 774         return i;
 775         }
 776
 777
 778 static long
 779 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
 780         {
 781         unsigned char wire[DTLS1_HM_HEADER_LENGTH];
 782         unsigned long len, frag_off, frag_len;
 783         int i,al;
 784         struct hm_header_st msg_hdr;
 785
 786         /* see if we have the required fragment already */
 787         if ((frag_len = dtls1_retrieve_buffered_fragment(s,max,ok)) || *ok)
 788                 {
 789                 if (*ok)        s->init_num = frag_len;
 790                 return frag_len;
 791                 }
 792
 793         /* read handshake message header */
 794         i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,wire,
 795                 DTLS1_HM_HEADER_LENGTH, 0);
 796         if (i <= 0)     /* nbio, or an error */
 797                 {
 798                 s->rwstate=SSL_READING;
 799                 *ok = 0;
 800                 return i;
 801                 }
 802         /* Handshake fails if message header is incomplete */
 803         if (i != DTLS1_HM_HEADER_LENGTH)
 804                 {
 805                 al=SSL_AD_UNEXPECTED_MESSAGE;
 806                 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 807                 goto f_err;
 808                 }
 809
 810         /* parse the message fragment header */
 811         dtls1_get_message_header(wire, &msg_hdr);
 812
 813         /*
 814          * if this is a future (or stale) message it gets buffered
 815          * (or dropped)--no further processing at this time
 816          * While listening, we accept seq 1 (ClientHello with cookie)
 817          * although we're still expecting seq 0 (ClientHello)
 818          */
 819         if (msg_hdr.seq != s->d1->handshake_read_seq && !(s->d1->listen && msg_hdr.seq == 1))
 820                 return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
 821
 822         len = msg_hdr.msg_len;
 823         frag_off = msg_hdr.frag_off;
 824         frag_len = msg_hdr.frag_len;
 825
 826         if (frag_len && frag_len < len)
 827                 return dtls1_reassemble_fragment(s, &msg_hdr, ok);
 828
 829         if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
 830                 wire[0] == SSL3_MT_HELLO_REQUEST)
 831                 {
 832                 /* The server may always send 'Hello Request' messages --
 833                  * we are doing a handshake anyway now, so ignore them
 834                  * if their format is correct. Does not count for
 835                  * 'Finished' MAC. */
 836                 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0)
 837                         {
 838                         if (s->msg_callback)
 839                                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 840                                         wire, DTLS1_HM_HEADER_LENGTH, s,
 841                                         s->msg_callback_arg);
 842
 843                         s->init_num = 0;
 844                         return dtls1_get_message_fragment(s, st1, stn,
 845                                 max, ok);
 846                         }
 847                 else /* Incorrectly formated Hello request */
 848                         {
 849                         al=SSL_AD_UNEXPECTED_MESSAGE;
 850                         SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 851                         goto f_err;
 852                         }
 853                 }
 854
 855         if ((al=dtls1_preprocess_fragment(s,&msg_hdr,max)))
 856                 goto f_err;
 857
 858         /* XDTLS:  ressurect this when restart is in place */
 859         s->state=stn;
 860
 861         if ( frag_len > 0)
 862                 {
 863                 unsigned char *p=(unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 864
 865                 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 866                         &p[frag_off],frag_len,0);
 867                 /* XDTLS:  fix this--message fragments cannot span multiple packets */
 868                 if (i <= 0)
 869                         {
 870                         s->rwstate=SSL_READING;
 871                         *ok = 0;
 872                         return i;
 873                         }
 874                 }
 875         else
 876                 i = 0;
 877
 878         /* XDTLS:  an incorrectly formatted fragment should cause the
 879          * handshake to fail */
 880         if (i != (int)frag_len)
 881                 {
 882                 al=SSL3_AD_ILLEGAL_PARAMETER;
 883                 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL3_AD_ILLEGAL_PARAMETER);
 884                 goto f_err;
 885                 }
 886
 887         *ok = 1;
 888
 889         /* Note that s->init_num is *not* used as current offset in
 890          * s->init_buf->data, but as a counter summing up fragments'
 891          * lengths: as soon as they sum up to handshake packet
 892          * length, we assume we have got all the fragments. */
 893         s->init_num = frag_len;
 894         return frag_len;
 895
 896 f_err:
 897         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 898         s->init_num = 0;
 899
 900         *ok=0;
 901         return(-1);
 902         }
 903
 904 /* for these 2 messages, we need to
 905  * ssl->enc_read_ctx                    re-init
 906  * ssl->s3->read_sequence               zero
 907  * ssl->s3->read_mac_secret             re-init
 908  * ssl->session->read_sym_enc           assign
 909  * ssl->session->read_compression       assign
 910  * ssl->session->read_hash              assign
 911  */
 912 int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
 913         {
 914         unsigned char *p;
 915
 916         if (s->state == a)
 917                 {
 918                 p=(unsigned char *)s->init_buf->data;
 919                 *p++=SSL3_MT_CCS;
 920                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
 921                 s->init_num=DTLS1_CCS_HEADER_LENGTH;
 922
 923                 if (s->version == DTLS1_BAD_VER) {
 924                         s->d1->next_handshake_write_seq++;
 925                         s2n(s->d1->handshake_write_seq,p);
 926                         s->init_num+=2;
 927                 }
 928
 929                 s->init_off=0;
 930
 931                 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
 932                         s->d1->handshake_write_seq, 0, 0);
 933
 934                 /* buffer the message to handle re-xmits */
 935                 dtls1_buffer_message(s, 1);
 936
 937                 s->state=b;
 938                 }
 939
 940         /* SSL3_ST_CW_CHANGE_B */
 941         return(dtls1_do_write(s,SSL3_RT_CHANGE_CIPHER_SPEC));
 942         }
 943
 944 int dtls1_read_failed(SSL *s, int code)
 945         {
 946         if ( code > 0)
 947                 {
 948                 fprintf( stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
 949                 return 1;
 950                 }
 951
 952         if (!dtls1_is_timer_expired(s))
 953                 {
 954                 /* not a timeout, none of our business,
 955                    let higher layers handle this.  in fact it's probably an error */
 956                 return code;
 957                 }
 958
 959 #ifndef OPENSSL_NO_HEARTBEATS
 960         if (!SSL_in_init(s) && !s->tlsext_hb_pending)  /* done, no need to send a retransmit */
 961 #else
 962         if (!SSL_in_init(s))  /* done, no need to send a retransmit */
 963 #endif
 964                 {
 965                 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
 966                 return code;
 967                 }
 968
 969 #if 0 /* for now, each alert contains only one record number */
 970         item = pqueue_peek(state->rcvd_records);
 971         if ( item )
 972                 {
 973                 /* send an alert immediately for all the missing records */
 974                 }
 975         else
 976 #endif
 977
 978 #if 0  /* no more alert sending, just retransmit the last set of messages */
 979         if ( state->timeout.read_timeouts >= DTLS1_TMO_READ_COUNT)
 980                 ssl3_send_alert(s,SSL3_AL_WARNING,
 981                         DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
 982 #endif
 983
 984         return dtls1_handle_timeout(s);
 985         }
 986
 987 int
 988 dtls1_get_queue_priority(unsigned short seq, int is_ccs)
 989         {
 990         /* The index of the retransmission queue actually is the message sequence number,
 991          * since the queue only contains messages of a single handshake. However, the
 992          * ChangeCipherSpec has no message sequence number and so using only the sequence
 993          * will result in the CCS and Finished having the same index. To prevent this,
 994          * the sequence number is multiplied by 2. In case of a CCS 1 is subtracted.
 995          * This does not only differ CSS and Finished, it also maintains the order of the
 996          * index (important for priority queues) and fits in the unsigned short variable.
 997          */
 998         return seq * 2 - is_ccs;
 999         }
1000
1001 int
1002 dtls1_retransmit_buffered_messages(SSL *s)
1003         {
1004         pqueue sent = s->d1->sent_messages;
1005         piterator iter;
1006         pitem *item;
1007         hm_fragment *frag;
1008         int found = 0;
1009
1010         iter = pqueue_iterator(sent);
1011
1012         for ( item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter))
1013                 {
1014                 frag = (hm_fragment *)item->data;
1015                         if ( dtls1_retransmit_message(s,
1016                                 (unsigned short)dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs),
1017                                 0, &found) <= 0 && found)
1018                         {
1019                         fprintf(stderr, "dtls1_retransmit_message() failed\n");
1020                         return -1;
1021                         }
1022                 }
1023
1024         return 1;
1025         }
1026
1027 int
1028 dtls1_buffer_message(SSL *s, int is_ccs)
1029         {
1030         pitem *item;
1031         hm_fragment *frag;
1032         unsigned char seq64be[8];
1033
1034         /* this function is called immediately after a message has
1035          * been serialized */
1036         OPENSSL_assert(s->init_off == 0);
1037
1038         frag = dtls1_hm_fragment_new(s->init_num, 0);
1039
1040         memcpy(frag->fragment, s->init_buf->data, s->init_num);
1041
1042         if ( is_ccs)
1043                 {
1044                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1045                                DTLS1_CCS_HEADER_LENGTH == (unsigned int)s->init_num);
1046                 }
1047         else
1048                 {
1049                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1050                         DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
1051                 }
1052
1053         frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1054         frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1055         frag->msg_header.type = s->d1->w_msg_hdr.type;
1056         frag->msg_header.frag_off = 0;
1057         frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1058         frag->msg_header.is_ccs = is_ccs;
1059
1060         /* save current state*/
1061         frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
1062         frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
1063         frag->msg_header.saved_retransmit_state.compress = s->compress;
1064         frag->msg_header.saved_retransmit_state.session = s->session;
1065         frag->msg_header.saved_retransmit_state.epoch = s->d1->w_epoch;
1066
1067         memset(seq64be,0,sizeof(seq64be));
1068         seq64be[6] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1069                                                                                                                   frag->msg_header.is_ccs)>>8);
1070         seq64be[7] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1071                                                                                                                   frag->msg_header.is_ccs));
1072
1073         item = pitem_new(seq64be, frag);
1074         if ( item == NULL)
1075                 {
1076                 dtls1_hm_fragment_free(frag);
1077                 return 0;
1078                 }
1079
1080 #if 0
1081         fprintf( stderr, "buffered messge: \ttype = %xx\n", msg_buf->type);
1082         fprintf( stderr, "\t\t\t\t\tlen = %d\n", msg_buf->len);
1083         fprintf( stderr, "\t\t\t\t\tseq_num = %d\n", msg_buf->seq_num);
1084 #endif
1085
1086         pqueue_insert(s->d1->sent_messages, item);
1087         return 1;
1088         }
1089
1090 int
1091 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
1092         int *found)
1093         {
1094         int ret;
1095         /* XDTLS: for now assuming that read/writes are blocking */
1096         pitem *item;
1097         hm_fragment *frag ;
1098         unsigned long header_length;
1099         unsigned char seq64be[8];
1100         struct dtls1_retransmit_state saved_state;
1101         unsigned char save_write_sequence[8];
1102
1103         /*
1104           OPENSSL_assert(s->init_num == 0);
1105           OPENSSL_assert(s->init_off == 0);
1106          */
1107
1108         /* XDTLS:  the requested message ought to be found, otherwise error */
1109         memset(seq64be,0,sizeof(seq64be));
1110         seq64be[6] = (unsigned char)(seq>>8);
1111         seq64be[7] = (unsigned char)seq;
1112
1113         item = pqueue_find(s->d1->sent_messages, seq64be);
1114         if ( item == NULL)
1115                 {
1116                 fprintf(stderr, "retransmit:  message %d non-existant\n", seq);
1117                 *found = 0;
1118                 return 0;
1119                 }
1120
1121         *found = 1;
1122         frag = (hm_fragment *)item->data;
1123
1124         if ( frag->msg_header.is_ccs)
1125                 header_length = DTLS1_CCS_HEADER_LENGTH;
1126         else
1127                 header_length = DTLS1_HM_HEADER_LENGTH;
1128
1129         memcpy(s->init_buf->data, frag->fragment,
1130                 frag->msg_header.msg_len + header_length);
1131                 s->init_num = frag->msg_header.msg_len + header_length;
1132
1133         dtls1_set_message_header_int(s, frag->msg_header.type,
1134                 frag->msg_header.msg_len, frag->msg_header.seq, 0,
1135                 frag->msg_header.frag_len);
1136
1137         /* save current state */
1138         saved_state.enc_write_ctx = s->enc_write_ctx;
1139         saved_state.write_hash = s->write_hash;
1140         saved_state.compress = s->compress;
1141         saved_state.session = s->session;
1142         saved_state.epoch = s->d1->w_epoch;
1143         saved_state.epoch = s->d1->w_epoch;
1144
1145         s->d1->retransmitting = 1;
1146
1147         /* restore state in which the message was originally sent */
1148         s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
1149         s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
1150         s->compress = frag->msg_header.saved_retransmit_state.compress;
1151         s->session = frag->msg_header.saved_retransmit_state.session;
1152         s->d1->w_epoch = frag->msg_header.saved_retransmit_state.epoch;
1153
1154         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1155         {
1156                 memcpy(save_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1157                 memcpy(s->s3->write_sequence, s->d1->last_write_sequence, sizeof(s->s3->write_sequence));
1158         }
1159
1160         ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1161                                                  SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1162
1163         /* restore current state */
1164         s->enc_write_ctx = saved_state.enc_write_ctx;
1165         s->write_hash = saved_state.write_hash;
1166         s->compress = saved_state.compress;
1167         s->session = saved_state.session;
1168         s->d1->w_epoch = saved_state.epoch;
1169
1170         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1171         {
1172                 memcpy(s->d1->last_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1173                 memcpy(s->s3->write_sequence, save_write_sequence, sizeof(s->s3->write_sequence));
1174         }
1175
1176         s->d1->retransmitting = 0;
1177
1178         (void)BIO_flush(SSL_get_wbio(s));
1179         return ret;
1180         }
1181
1182 /* call this function when the buffered messages are no longer needed */
1183 void
1184 dtls1_clear_record_buffer(SSL *s)
1185         {
1186         pitem *item;
1187
1188         for(item = pqueue_pop(s->d1->sent_messages);
1189                 item != NULL; item = pqueue_pop(s->d1->sent_messages))
1190                 {
1191                 dtls1_hm_fragment_free((hm_fragment *)item->data);
1192                 pitem_free(item);
1193                 }
1194         }
1195
1196
1197 unsigned char *
1198 dtls1_set_message_header(SSL *s, unsigned char *p, unsigned char mt,
1199                         unsigned long len, unsigned long frag_off, unsigned long frag_len)
1200         {
1201         /* Don't change sequence numbers while listening */
1202         if (frag_off == 0 && !s->d1->listen)
1203                 {
1204                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1205                 s->d1->next_handshake_write_seq++;
1206                 }
1207
1208         dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1209                 frag_off, frag_len);
1210
1211         return p += DTLS1_HM_HEADER_LENGTH;
1212         }
1213
1214
1215 /* don't actually do the writing, wait till the MTU has been retrieved */
1216 static void
1217 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1218                             unsigned long len, unsigned short seq_num, unsigned long frag_off,
1219                             unsigned long frag_len)
1220         {
1221         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1222
1223         msg_hdr->type = mt;
1224         msg_hdr->msg_len = len;
1225         msg_hdr->seq = seq_num;
1226         msg_hdr->frag_off = frag_off;
1227         msg_hdr->frag_len = frag_len;
1228         }
1229
1230 static void
1231 dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1232                         unsigned long frag_len)
1233         {
1234         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1235
1236         msg_hdr->frag_off = frag_off;
1237         msg_hdr->frag_len = frag_len;
1238         }
1239
1240 static unsigned char *
1241 dtls1_write_message_header(SSL *s, unsigned char *p)
1242         {
1243         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1244
1245         *p++ = msg_hdr->type;
1246         l2n3(msg_hdr->msg_len, p);
1247
1248         s2n(msg_hdr->seq, p);
1249         l2n3(msg_hdr->frag_off, p);
1250         l2n3(msg_hdr->frag_len, p);
1251
1252         return p;
1253         }
1254
1255 unsigned int
1256 dtls1_min_mtu(void)
1257         {
1258         return (g_probable_mtu[(sizeof(g_probable_mtu) /
1259                 sizeof(g_probable_mtu[0])) - 1]);
1260         }
1261
1262 static unsigned int
1263 dtls1_guess_mtu(unsigned int curr_mtu)
1264         {
1265         unsigned int i;
1266
1267         if ( curr_mtu == 0 )
1268                 return g_probable_mtu[0] ;
1269
1270         for ( i = 0; i < sizeof(g_probable_mtu)/sizeof(g_probable_mtu[0]); i++)
1271                 if ( curr_mtu > g_probable_mtu[i])
1272                         return g_probable_mtu[i];
1273
1274         return curr_mtu;
1275         }
1276
1277 void
1278 dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1279         {
1280         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
1281         msg_hdr->type = *(data++);
1282         n2l3(data, msg_hdr->msg_len);
1283
1284         n2s(data, msg_hdr->seq);
1285         n2l3(data, msg_hdr->frag_off);
1286         n2l3(data, msg_hdr->frag_len);
1287         }
1288
1289 void
1290 dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
1291         {
1292         memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
1293
1294         ccs_hdr->type = *(data++);
1295         }
1296
1297 int dtls1_shutdown(SSL *s)
1298         {
1299         int ret;
1300 #ifndef OPENSSL_NO_SCTP
1301         if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
1302             !(s->shutdown & SSL_SENT_SHUTDOWN))
1303                 {
1304                 ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
1305                 if (ret < 0) return -1;
1306
1307                 if (ret == 0)
1308                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1, NULL);
1309                 }
1310 #endif
1311         ret = ssl3_shutdown(s);
1312 #ifndef OPENSSL_NO_SCTP
1313         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
1314 #endif
1315         return ret;
1316         }
1317
1318 #ifndef OPENSSL_NO_HEARTBEATS
1319 int
1320 dtls1_process_heartbeat(SSL *s)
1321         {
1322         unsigned char *p = &s->s3->rrec.data[0], *pl;
1323         unsigned short hbtype;
1324         unsigned int payload;
1325         unsigned int padding = 16; /* Use minimum padding */
1326
1327         /* Read type and payload length first */
1328         hbtype = *p++;
1329         n2s(p, payload);
1330         pl = p;
1331
1332         if (s->msg_callback)
1333                 s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
1334                         &s->s3->rrec.data[0], s->s3->rrec.length,
1335                         s, s->msg_callback_arg);
1336
1337         if (hbtype == TLS1_HB_REQUEST)
1338                 {
1339                 unsigned char *buffer, *bp;
1340                 int r;
1341
1342                 /* Allocate memory for the response, size is 1 byte
1343                  * message type, plus 2 bytes payload length, plus
1344                  * payload, plus padding
1345                  */
1346                 buffer = OPENSSL_malloc(1 + 2 + payload + padding);
1347                 bp = buffer;
1348
1349                 /* Enter response type, length and copy payload */
1350                 *bp++ = TLS1_HB_RESPONSE;
1351                 s2n(payload, bp);
1352                 memcpy(bp, pl, payload);
1353                 bp += payload;
1354                 /* Random padding */
1355                 RAND_pseudo_bytes(bp, padding);
1356
1357                 r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, 3 + payload + padding);
1358
1359                 if (r >= 0 && s->msg_callback)
1360                         s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1361                                 buffer, 3 + payload + padding,
1362                                 s, s->msg_callback_arg);
1363
1364                 OPENSSL_free(buffer);
1365
1366                 if (r < 0)
1367                         return r;
1368                 }
1369         else if (hbtype == TLS1_HB_RESPONSE)
1370                 {
1371                 unsigned int seq;
1372
1373                 /* We only send sequence numbers (2 bytes unsigned int),
1374                  * and 16 random bytes, so we just try to read the
1375                  * sequence number */
1376                 n2s(pl, seq);
1377
1378                 if (payload == 18 && seq == s->tlsext_hb_seq)
1379                         {
1380                         dtls1_stop_timer(s);
1381                         s->tlsext_hb_seq++;
1382                         s->tlsext_hb_pending = 0;
1383                         }
1384                 }
1385
1386         return 0;
1387         }
1388
1389 int
1390 dtls1_heartbeat(SSL *s)
1391         {
1392         unsigned char *buf, *p;
1393         int ret;
1394         unsigned int payload = 18; /* Sequence number + random bytes */
1395         unsigned int padding = 16; /* Use minimum padding */
1396
1397         /* Only send if peer supports and accepts HB requests... */
1398         if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
1399             s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS)
1400                 {
1401                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
1402                 return -1;
1403                 }
1404
1405         /* ...and there is none in flight yet... */
1406         if (s->tlsext_hb_pending)
1407                 {
1408                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PENDING);
1409                 return -1;
1410                 }
1411
1412         /* ...and no handshake in progress. */
1413         if (SSL_in_init(s) || s->in_handshake)
1414                 {
1415                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_UNEXPECTED_MESSAGE);
1416                 return -1;
1417                 }
1418
1419         /* Check if padding is too long, payload and padding
1420          * must not exceed 2^14 - 3 = 16381 bytes in total.
1421          */
1422         OPENSSL_assert(payload + padding <= 16381);
1423
1424         /* Create HeartBeat message, we just use a sequence number
1425          * as payload to distuingish different messages and add
1426          * some random stuff.
1427          *  - Message Type, 1 byte
1428          *  - Payload Length, 2 bytes (unsigned int)
1429          *  - Payload, the sequence number (2 bytes uint)
1430          *  - Payload, random bytes (16 bytes uint)
1431          *  - Padding
1432          */
1433         buf = OPENSSL_malloc(1 + 2 + payload + padding);
1434         p = buf;
1435         /* Message Type */
1436         *p++ = TLS1_HB_REQUEST;
1437         /* Payload length (18 bytes here) */
1438         s2n(payload, p);
1439         /* Sequence number */
1440         s2n(s->tlsext_hb_seq, p);
1441         /* 16 random bytes */
1442         RAND_pseudo_bytes(p, 16);
1443         p += 16;
1444         /* Random padding */
1445         RAND_pseudo_bytes(p, padding);
1446
1447         ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
1448         if (ret >= 0)
1449                 {
1450                 if (s->msg_callback)
1451                         s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1452                                 buf, 3 + payload + padding,
1453                                 s, s->msg_callback_arg);
1454
1455                 dtls1_start_timer(s);
1456                 s->tlsext_hb_pending = 1;
1457                 }
1458
1459         OPENSSL_free(buf);
1460
1461         return ret;
1462         }
1463 #endif