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
 127 /* XDTLS:  figure out the right values */
 128 static unsigned int g_probable_mtu[] = {1500 - 28, 512 - 28, 256 - 28};
 129
 130 static unsigned int dtls1_min_mtu(void);
 131 static unsigned int dtls1_guess_mtu(unsigned int curr_mtu);
 132 static void dtls1_fix_message_header(SSL *s, unsigned long frag_off,
 133         unsigned long frag_len);
 134 static unsigned char *dtls1_write_message_header(SSL *s,
 135         unsigned char *p);
 136 static void dtls1_set_message_header_int(SSL *s, unsigned char mt,
 137         unsigned long len, unsigned short seq_num, unsigned long frag_off,
 138         unsigned long frag_len);
 139 static long dtls1_get_message_fragment(SSL *s, int st1, int stn,
 140         long max, int *ok);
 141
 142 static hm_fragment *
 143 dtls1_hm_fragment_new(unsigned long frag_len)
 144         {
 145         hm_fragment *frag = NULL;
 146         unsigned char *buf = NULL;
 147
 148         frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment));
 149         if ( frag == NULL)
 150                 return NULL;
 151
 152         if (frag_len)
 153                 {
 154                 buf = (unsigned char *)OPENSSL_malloc(frag_len);
 155                 if ( buf == NULL)
 156                         {
 157                         OPENSSL_free(frag);
 158                         return NULL;
 159                         }
 160                 }
 161
 162         /* zero length fragment gets zero frag->fragment */
 163         frag->fragment = buf;
 164
 165         return frag;
 166         }
 167
 168 static void
 169 dtls1_hm_fragment_free(hm_fragment *frag)
 170         {
 171         if (frag->fragment) OPENSSL_free(frag->fragment);
 172         OPENSSL_free(frag);
 173         }
 174
 175 /* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
 176 int dtls1_do_write(SSL *s, int type)
 177         {
 178         int ret;
 179         int curr_mtu;
 180         unsigned int len, frag_off, mac_size, blocksize;
 181
 182         /* AHA!  Figure out the MTU, and stick to the right size */
 183         if ( ! (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
 184                 {
 185                 s->d1->mtu =
 186                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
 187
 188                 /* I've seen the kernel return bogus numbers when it doesn't know
 189                  * (initial write), so just make sure we have a reasonable number */
 190                 if ( s->d1->mtu < dtls1_min_mtu())
 191                         {
 192                         s->d1->mtu = 0;
 193                         s->d1->mtu = dtls1_guess_mtu(s->d1->mtu);
 194                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
 195                                 s->d1->mtu, NULL);
 196                         }
 197                 }
 198 #if 0
 199         mtu = s->d1->mtu;
 200
 201         fprintf(stderr, "using MTU = %d\n", mtu);
 202
 203         mtu -= (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 204
 205         curr_mtu = mtu - BIO_wpending(SSL_get_wbio(s));
 206
 207         if ( curr_mtu > 0)
 208                 mtu = curr_mtu;
 209         else if ( ( ret = BIO_flush(SSL_get_wbio(s))) <= 0)
 210                 return ret;
 211
 212         if ( BIO_wpending(SSL_get_wbio(s)) + s->init_num >= mtu)
 213                 {
 214                 ret = BIO_flush(SSL_get_wbio(s));
 215                 if ( ret <= 0)
 216                         return ret;
 217                 mtu = s->d1->mtu - (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 218                 }
 219
 220         OPENSSL_assert(mtu > 0);  /* should have something reasonable now */
 221
 222 #endif
 223
 224         if ( s->init_off == 0  && type == SSL3_RT_HANDSHAKE)
 225                 OPENSSL_assert(s->init_num ==
 226                         (int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH);
 227
 228         if (s->write_hash)
 229                 mac_size = EVP_MD_CTX_size(s->write_hash);
 230         else
 231                 mac_size = 0;
 232
 233         if (s->enc_write_ctx &&
 234                 (EVP_CIPHER_mode( s->enc_write_ctx->cipher) & EVP_CIPH_CBC_MODE))
 235                 blocksize = 2 * EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
 236         else
 237                 blocksize = 0;
 238
 239         frag_off = 0;
 240         while( s->init_num)
 241                 {
 242                 curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) -
 243                         DTLS1_RT_HEADER_LENGTH - mac_size - blocksize;
 244
 245                 if ( curr_mtu <= DTLS1_HM_HEADER_LENGTH)
 246                         {
 247                         /* grr.. we could get an error if MTU picked was wrong */
 248                         ret = BIO_flush(SSL_get_wbio(s));
 249                         if ( ret <= 0)
 250                                 return ret;
 251                         curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH -
 252                                 mac_size - blocksize;
 253                         }
 254
 255                 if ( s->init_num > curr_mtu)
 256                         len = curr_mtu;
 257                 else
 258                         len = s->init_num;
 259
 260
 261                 /* XDTLS: this function is too long.  split out the CCS part */
 262                 if ( type == SSL3_RT_HANDSHAKE)
 263                         {
 264                         if ( s->init_off != 0)
 265                                 {
 266                                 OPENSSL_assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
 267                                 s->init_off -= DTLS1_HM_HEADER_LENGTH;
 268                                 s->init_num += DTLS1_HM_HEADER_LENGTH;
 269
 270                                 /* write atleast DTLS1_HM_HEADER_LENGTH bytes */
 271                                 if ( len <= DTLS1_HM_HEADER_LENGTH)
 272                                         len += DTLS1_HM_HEADER_LENGTH;
 273                                 }
 274
 275                         dtls1_fix_message_header(s, frag_off,
 276                                 len - DTLS1_HM_HEADER_LENGTH);
 277
 278                         dtls1_write_message_header(s, (unsigned char *)&s->init_buf->data[s->init_off]);
 279
 280                         OPENSSL_assert(len >= DTLS1_HM_HEADER_LENGTH);
 281                         }
 282
 283                 ret=dtls1_write_bytes(s,type,&s->init_buf->data[s->init_off],
 284                         len);
 285                 if (ret < 0)
 286                         {
 287                         /* might need to update MTU here, but we don't know
 288                          * which previous packet caused the failure -- so can't
 289                          * really retransmit anything.  continue as if everything
 290                          * is fine and wait for an alert to handle the
 291                          * retransmit
 292                          */
 293                         if ( BIO_ctrl(SSL_get_wbio(s),
 294                                 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0 )
 295                                 s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
 296                                         BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
 297                         else
 298                                 return(-1);
 299                         }
 300                 else
 301                         {
 302
 303                         /* bad if this assert fails, only part of the handshake
 304                          * message got sent.  but why would this happen? */
 305                         OPENSSL_assert(len == (unsigned int)ret);
 306
 307                         if (type == SSL3_RT_HANDSHAKE && ! s->d1->retransmitting)
 308                                 {
 309                                 /* should not be done for 'Hello Request's, but in that case
 310                                  * we'll ignore the result anyway */
 311                                 unsigned char *p = (unsigned char *)&s->init_buf->data[s->init_off];
 312                                 const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
 313                                 int xlen;
 314
 315                                 if (frag_off == 0 && s->version != DTLS1_BAD_VER)
 316                                         {
 317                                         /* reconstruct message header is if it
 318                                          * is being sent in single fragment */
 319                                         *p++ = msg_hdr->type;
 320                                         l2n3(msg_hdr->msg_len,p);
 321                                         s2n (msg_hdr->seq,p);
 322                                         l2n3(0,p);
 323                                         l2n3(msg_hdr->msg_len,p);
 324                                         p  -= DTLS1_HM_HEADER_LENGTH;
 325                                         xlen = ret;
 326                                         }
 327                                 else
 328                                         {
 329                                         p  += DTLS1_HM_HEADER_LENGTH;
 330                                         xlen = ret - DTLS1_HM_HEADER_LENGTH;
 331                                         }
 332
 333                                 ssl3_finish_mac(s, p, xlen);
 334                                 }
 335
 336                         if (ret == s->init_num)
 337                                 {
 338                                 if (s->msg_callback)
 339                                         s->msg_callback(1, s->version, type, s->init_buf->data,
 340                                                 (size_t)(s->init_off + s->init_num), s,
 341                                                 s->msg_callback_arg);
 342
 343                                 s->init_off = 0;  /* done writing this message */
 344                                 s->init_num = 0;
 345
 346                                 return(1);
 347                                 }
 348                         s->init_off+=ret;
 349                         s->init_num-=ret;
 350                         frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
 351                         }
 352                 }
 353         return(0);
 354         }
 355
 356
 357 /* Obtain handshake message of message type 'mt' (any if mt == -1),
 358  * maximum acceptable body length 'max'.
 359  * Read an entire handshake message.  Handshake messages arrive in
 360  * fragments.
 361  */
 362 long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
 363         {
 364         int i, al;
 365         struct hm_header_st *msg_hdr;
 366
 367         /* s3->tmp is used to store messages that are unexpected, caused
 368          * by the absence of an optional handshake message */
 369         if (s->s3->tmp.reuse_message)
 370                 {
 371                 s->s3->tmp.reuse_message=0;
 372                 if ((mt >= 0) && (s->s3->tmp.message_type != mt))
 373                         {
 374                         al=SSL_AD_UNEXPECTED_MESSAGE;
 375                         SSLerr(SSL_F_DTLS1_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
 376                         goto f_err;
 377                         }
 378                 *ok=1;
 379                 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 380                 s->init_num = (int)s->s3->tmp.message_size;
 381                 return s->init_num;
 382                 }
 383
 384         msg_hdr = &s->d1->r_msg_hdr;
 385         do
 386                 {
 387                 if ( msg_hdr->frag_off == 0)
 388                         {
 389                         /* s->d1->r_message_header.msg_len = 0; */
 390                         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 391                         }
 392
 393                 i = dtls1_get_message_fragment(s, st1, stn, max, ok);
 394                 if ( i == DTLS1_HM_BAD_FRAGMENT ||
 395                         i == DTLS1_HM_FRAGMENT_RETRY)  /* bad fragment received */
 396                         continue;
 397                 else if ( i <= 0 && !*ok)
 398                         return i;
 399
 400                 /* Note that s->init_sum is used as a counter summing
 401                  * up fragments' lengths: as soon as they sum up to
 402                  * handshake packet length, we assume we have got all
 403                  * the fragments. Overlapping fragments would cause
 404                  * premature termination, so we don't expect overlaps.
 405                  * Well, handling overlaps would require something more
 406                  * drastic. Indeed, as it is now there is no way to
 407                  * tell if out-of-order fragment from the middle was
 408                  * the last. '>=' is the best/least we can do to control
 409                  * the potential damage caused by malformed overlaps. */
 410                 if ((unsigned int)s->init_num >= msg_hdr->msg_len)
 411                         {
 412                         unsigned char *p = (unsigned char *)s->init_buf->data;
 413                         unsigned long msg_len = msg_hdr->msg_len;
 414
 415                         /* reconstruct message header as if it was
 416                          * sent in single fragment */
 417                         *(p++) = msg_hdr->type;
 418                         l2n3(msg_len,p);
 419                         s2n (msg_hdr->seq,p);
 420                         l2n3(0,p);
 421                         l2n3(msg_len,p);
 422                         if (s->version != DTLS1_BAD_VER) {
 423                                 p       -= DTLS1_HM_HEADER_LENGTH;
 424                                 msg_len += DTLS1_HM_HEADER_LENGTH;
 425                         }
 426
 427                         ssl3_finish_mac(s, p, msg_len);
 428                         if (s->msg_callback)
 429                                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 430                                         p, msg_len,
 431                                         s, s->msg_callback_arg);
 432
 433                         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 434
 435                         s->d1->handshake_read_seq++;
 436                         /* we just read a handshake message from the other side:
 437                          * this means that we don't need to retransmit of the
 438                          * buffered messages.
 439                          * XDTLS: may be able clear out this
 440                          * buffer a little sooner (i.e if an out-of-order
 441                          * handshake message/record is received at the record
 442                          * layer.
 443                          * XDTLS: exception is that the server needs to
 444                          * know that change cipher spec and finished messages
 445                          * have been received by the client before clearing this
 446                          * buffer.  this can simply be done by waiting for the
 447                          * first data  segment, but is there a better way?  */
 448                         dtls1_clear_record_buffer(s);
 449
 450                         s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 451                         return s->init_num;
 452                         }
 453                 else
 454                         msg_hdr->frag_off = i;
 455                 } while(1) ;
 456
 457 f_err:
 458         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 459         *ok = 0;
 460         return -1;
 461         }
 462
 463
 464 static int dtls1_preprocess_fragment(SSL *s,struct hm_header_st *msg_hdr,int max)
 465         {
 466         size_t frag_off,frag_len,msg_len;
 467
 468         msg_len  = msg_hdr->msg_len;
 469         frag_off = msg_hdr->frag_off;
 470         frag_len = msg_hdr->frag_len;
 471
 472         /* sanity checking */
 473         if ( (frag_off+frag_len) > msg_len)
 474                 {
 475                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 476                 return SSL_AD_ILLEGAL_PARAMETER;
 477                 }
 478
 479         if ( (frag_off+frag_len) > (unsigned long)max)
 480                 {
 481                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 482                 return SSL_AD_ILLEGAL_PARAMETER;
 483                 }
 484
 485         if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */
 486                 {
 487                 /* msg_len is limited to 2^24, but is effectively checked
 488                  * against max above */
 489                 if (!BUF_MEM_grow_clean(s->init_buf,msg_len+DTLS1_HM_HEADER_LENGTH))
 490                         {
 491                         SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,ERR_R_BUF_LIB);
 492                         return SSL_AD_INTERNAL_ERROR;
 493                         }
 494
 495                 s->s3->tmp.message_size  = msg_len;
 496                 s->d1->r_msg_hdr.msg_len = msg_len;
 497                 s->s3->tmp.message_type  = msg_hdr->type;
 498                 s->d1->r_msg_hdr.type    = msg_hdr->type;
 499                 s->d1->r_msg_hdr.seq     = msg_hdr->seq;
 500                 }
 501         else if (msg_len != s->d1->r_msg_hdr.msg_len)
 502                 {
 503                 /* They must be playing with us! BTW, failure to enforce
 504                  * upper limit would open possibility for buffer overrun. */
 505                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 506                 return SSL_AD_ILLEGAL_PARAMETER;
 507                 }
 508
 509         return 0; /* no error */
 510         }
 511
 512
 513 static int
 514 dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok)
 515         {
 516         /* (0) check whether the desired fragment is available
 517          * if so:
 518          * (1) copy over the fragment to s->init_buf->data[]
 519          * (2) update s->init_num
 520          */
 521         pitem *item;
 522         hm_fragment *frag;
 523         int al;
 524
 525         *ok = 0;
 526         item = pqueue_peek(s->d1->buffered_messages);
 527         if ( item == NULL)
 528                 return 0;
 529
 530         frag = (hm_fragment *)item->data;
 531
 532         if ( s->d1->handshake_read_seq == frag->msg_header.seq)
 533                 {
 534                 unsigned long frag_len = frag->msg_header.frag_len;
 535                 pqueue_pop(s->d1->buffered_messages);
 536
 537                 al=dtls1_preprocess_fragment(s,&frag->msg_header,max);
 538
 539                 if (al==0) /* no alert */
 540                         {
 541                         unsigned char *p = (unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 542                         memcpy(&p[frag->msg_header.frag_off],
 543                                 frag->fragment,frag->msg_header.frag_len);
 544                         }
 545
 546                 dtls1_hm_fragment_free(frag);
 547                 pitem_free(item);
 548
 549                 if (al==0)
 550                         {
 551                         *ok = 1;
 552                         return frag_len;
 553                         }
 554
 555                 ssl3_send_alert(s,SSL3_AL_FATAL,al);
 556                 s->init_num = 0;
 557                 *ok = 0;
 558                 return -1;
 559                 }
 560         else
 561                 return 0;
 562         }
 563
 564
 565 static int
 566 dtls1_process_out_of_seq_message(SSL *s, struct hm_header_st* msg_hdr, int *ok)
 567 {
 568         int i=-1;
 569         hm_fragment *frag = NULL;
 570         pitem *item = NULL;
 571         unsigned char seq64be[8];
 572         unsigned long frag_len = msg_hdr->frag_len;
 573
 574         if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
 575                 goto err;
 576
 577         /* Try to find item in queue, to prevent duplicate entries */
 578         memset(seq64be,0,sizeof(seq64be));
 579         seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
 580         seq64be[7] = (unsigned char) msg_hdr->seq;
 581         item = pqueue_find(s->d1->buffered_messages, seq64be);
 582
 583         /* Discard the message if sequence number was already there, is
 584          * too far in the future, already in the queue or if we received
 585          * a FINISHED before the SERVER_HELLO, which then must be a stale
 586          * retransmit.
 587          */
 588         if (msg_hdr->seq <= s->d1->handshake_read_seq ||
 589                 msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
 590                 (s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED))
 591                 {
 592                 unsigned char devnull [256];
 593
 594                 while (frag_len)
 595                         {
 596                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 597                                 devnull,
 598                                 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
 599                         if (i<=0) goto err;
 600                         frag_len -= i;
 601                         }
 602                 }
 603
 604         if (frag_len)
 605                 {
 606                 frag = dtls1_hm_fragment_new(frag_len);
 607                 if ( frag == NULL)
 608                         goto err;
 609
 610                 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 611
 612                 /* read the body of the fragment (header has already been read */
 613                 i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 614                         frag->fragment,frag_len,0);
 615                 if (i<=0 || (unsigned long)i!=frag_len)
 616                         goto err;
 617
 618                 memset(seq64be,0,sizeof(seq64be));
 619                 seq64be[6] = (unsigned char)(msg_hdr->seq>>8);
 620                 seq64be[7] = (unsigned char)(msg_hdr->seq);
 621
 622                 item = pitem_new(seq64be, frag);
 623                 if ( item == NULL)
 624                         goto err;
 625
 626                 pqueue_insert(s->d1->buffered_messages, item);
 627                 }
 628
 629         return DTLS1_HM_FRAGMENT_RETRY;
 630
 631 err:
 632         if ( frag != NULL) dtls1_hm_fragment_free(frag);
 633         if ( item != NULL) OPENSSL_free(item);
 634         *ok = 0;
 635         return i;
 636         }
 637
 638
 639 static long
 640 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
 641         {
 642         unsigned char wire[DTLS1_HM_HEADER_LENGTH];
 643         unsigned long l, frag_off, frag_len;
 644         int i,al;
 645         struct hm_header_st msg_hdr;
 646
 647         /* see if we have the required fragment already */
 648         if ((frag_len = dtls1_retrieve_buffered_fragment(s,max,ok)) || *ok)
 649                 {
 650                 if (*ok)        s->init_num += frag_len;
 651                 return frag_len;
 652                 }
 653
 654         /* read handshake message header */
 655         i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,wire,
 656                 DTLS1_HM_HEADER_LENGTH, 0);
 657         if (i <= 0)     /* nbio, or an error */
 658                 {
 659                 s->rwstate=SSL_READING;
 660                 *ok = 0;
 661                 return i;
 662                 }
 663         OPENSSL_assert(i == DTLS1_HM_HEADER_LENGTH);
 664
 665         /* parse the message fragment header */
 666         dtls1_get_message_header(wire, &msg_hdr);
 667
 668         /*
 669          * if this is a future (or stale) message it gets buffered
 670          * (or dropped)--no further processing at this time
 671          */
 672         if ( msg_hdr.seq != s->d1->handshake_read_seq)
 673                 return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
 674
 675         l = msg_hdr.msg_len;
 676         frag_off = msg_hdr.frag_off;
 677         frag_len = msg_hdr.frag_len;
 678
 679         if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
 680                 wire[0] == SSL3_MT_HELLO_REQUEST)
 681                 {
 682                 /* The server may always send 'Hello Request' messages --
 683                  * we are doing a handshake anyway now, so ignore them
 684                  * if their format is correct. Does not count for
 685                  * 'Finished' MAC. */
 686                 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0)
 687                         {
 688                         if (s->msg_callback)
 689                                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 690                                         wire, DTLS1_HM_HEADER_LENGTH, s,
 691                                         s->msg_callback_arg);
 692
 693                         s->init_num = 0;
 694                         return dtls1_get_message_fragment(s, st1, stn,
 695                                 max, ok);
 696                         }
 697                 else /* Incorrectly formated Hello request */
 698                         {
 699                         al=SSL_AD_UNEXPECTED_MESSAGE;
 700                         SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 701                         goto f_err;
 702                         }
 703                 }
 704
 705         if ((al=dtls1_preprocess_fragment(s,&msg_hdr,max)))
 706                 goto f_err;
 707
 708         /* XDTLS:  ressurect this when restart is in place */
 709         s->state=stn;
 710
 711         if ( frag_len > 0)
 712                 {
 713                 unsigned char *p=(unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 714
 715                 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 716                         &p[frag_off],frag_len,0);
 717                 /* XDTLS:  fix this--message fragments cannot span multiple packets */
 718                 if (i <= 0)
 719                         {
 720                         s->rwstate=SSL_READING;
 721                         *ok = 0;
 722                         return i;
 723                         }
 724                 }
 725         else
 726                 i = 0;
 727
 728         /* XDTLS:  an incorrectly formatted fragment should cause the
 729          * handshake to fail */
 730         OPENSSL_assert(i == (int)frag_len);
 731
 732         *ok = 1;
 733
 734         /* Note that s->init_num is *not* used as current offset in
 735          * s->init_buf->data, but as a counter summing up fragments'
 736          * lengths: as soon as they sum up to handshake packet
 737          * length, we assume we have got all the fragments. */
 738         s->init_num += frag_len;
 739         return frag_len;
 740
 741 f_err:
 742         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 743         s->init_num = 0;
 744
 745         *ok=0;
 746         return(-1);
 747         }
 748
 749 int dtls1_send_finished(SSL *s, int a, int b, const char *sender, int slen)
 750         {
 751         unsigned char *p,*d;
 752         int i;
 753         unsigned long l;
 754
 755         if (s->state == a)
 756                 {
 757                 d=(unsigned char *)s->init_buf->data;
 758                 p= &(d[DTLS1_HM_HEADER_LENGTH]);
 759
 760                 i=s->method->ssl3_enc->final_finish_mac(s,
 761                         sender,slen,s->s3->tmp.finish_md);
 762                 s->s3->tmp.finish_md_len = i;
 763                 memcpy(p, s->s3->tmp.finish_md, i);
 764                 p+=i;
 765                 l=i;
 766
 767         /* Copy the finished so we can use it for
 768          * renegotiation checks
 769          */
 770         if(s->type == SSL_ST_CONNECT)
 771                 {
 772                 OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
 773                 memcpy(s->s3->previous_client_finished,
 774                        s->s3->tmp.finish_md, i);
 775                 s->s3->previous_client_finished_len=i;
 776                 }
 777         else
 778                 {
 779                 OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
 780                 memcpy(s->s3->previous_server_finished,
 781                        s->s3->tmp.finish_md, i);
 782                 s->s3->previous_server_finished_len=i;
 783                 }
 784
 785 #ifdef OPENSSL_SYS_WIN16
 786                 /* MSVC 1.5 does not clear the top bytes of the word unless
 787                  * I do this.
 788                  */
 789                 l&=0xffff;
 790 #endif
 791
 792                 d = dtls1_set_message_header(s, d, SSL3_MT_FINISHED, l, 0, l);
 793                 s->init_num=(int)l+DTLS1_HM_HEADER_LENGTH;
 794                 s->init_off=0;
 795
 796                 /* buffer the message to handle re-xmits */
 797                 dtls1_buffer_message(s, 0);
 798
 799                 s->state=b;
 800                 }
 801
 802         /* SSL3_ST_SEND_xxxxxx_HELLO_B */
 803         return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
 804         }
 805
 806 /* for these 2 messages, we need to
 807  * ssl->enc_read_ctx                    re-init
 808  * ssl->s3->read_sequence               zero
 809  * ssl->s3->read_mac_secret             re-init
 810  * ssl->session->read_sym_enc           assign
 811  * ssl->session->read_compression       assign
 812  * ssl->session->read_hash              assign
 813  */
 814 int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
 815         {
 816         unsigned char *p;
 817
 818         if (s->state == a)
 819                 {
 820                 p=(unsigned char *)s->init_buf->data;
 821                 *p++=SSL3_MT_CCS;
 822                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
 823                 s->init_num=DTLS1_CCS_HEADER_LENGTH;
 824
 825                 if (s->version == DTLS1_BAD_VER) {
 826                         s->d1->next_handshake_write_seq++;
 827                         s2n(s->d1->handshake_write_seq,p);
 828                         s->init_num+=2;
 829                 }
 830
 831                 s->init_off=0;
 832
 833                 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
 834                         s->d1->handshake_write_seq, 0, 0);
 835
 836                 /* buffer the message to handle re-xmits */
 837                 dtls1_buffer_message(s, 1);
 838
 839                 s->state=b;
 840                 }
 841
 842         /* SSL3_ST_CW_CHANGE_B */
 843         return(dtls1_do_write(s,SSL3_RT_CHANGE_CIPHER_SPEC));
 844         }
 845
 846 static int dtls1_add_cert_to_buf(BUF_MEM *buf, unsigned long *l, X509 *x)
 847         {
 848         int n;
 849         unsigned char *p;
 850
 851         n=i2d_X509(x,NULL);
 852         if (!BUF_MEM_grow_clean(buf,(int)(n+(*l)+3)))
 853                 {
 854                 SSLerr(SSL_F_DTLS1_ADD_CERT_TO_BUF,ERR_R_BUF_LIB);
 855                 return 0;
 856                 }
 857         p=(unsigned char *)&(buf->data[*l]);
 858         l2n3(n,p);
 859         i2d_X509(x,&p);
 860         *l+=n+3;
 861
 862         return 1;
 863         }
 864 unsigned long dtls1_output_cert_chain(SSL *s, X509 *x)
 865         {
 866         unsigned char *p;
 867         int i;
 868         unsigned long l= 3 + DTLS1_HM_HEADER_LENGTH;
 869         BUF_MEM *buf;
 870
 871         /* TLSv1 sends a chain with nothing in it, instead of an alert */
 872         buf=s->init_buf;
 873         if (!BUF_MEM_grow_clean(buf,10))
 874                 {
 875                 SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
 876                 return(0);
 877                 }
 878         if (x != NULL)
 879                 {
 880                 X509_STORE_CTX xs_ctx;
 881
 882                 if (!X509_STORE_CTX_init(&xs_ctx,s->ctx->cert_store,x,NULL))
 883                         {
 884                         SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_X509_LIB);
 885                         return(0);
 886                         }
 887
 888                 X509_verify_cert(&xs_ctx);
 889                 for (i=0; i < sk_X509_num(xs_ctx.chain); i++)
 890                         {
 891                         x = sk_X509_value(xs_ctx.chain, i);
 892
 893                         if (!dtls1_add_cert_to_buf(buf, &l, x))
 894                                 {
 895                                 X509_STORE_CTX_cleanup(&xs_ctx);
 896                                 return 0;
 897                                 }
 898                         }
 899                 X509_STORE_CTX_cleanup(&xs_ctx);
 900                 }
 901         /* Thawte special :-) */
 902         for (i=0; i<sk_X509_num(s->ctx->extra_certs); i++)
 903                 {
 904                 x=sk_X509_value(s->ctx->extra_certs,i);
 905                 if (!dtls1_add_cert_to_buf(buf, &l, x))
 906                         return 0;
 907                 }
 908
 909         l-= (3 + DTLS1_HM_HEADER_LENGTH);
 910
 911         p=(unsigned char *)&(buf->data[DTLS1_HM_HEADER_LENGTH]);
 912         l2n3(l,p);
 913         l+=3;
 914         p=(unsigned char *)&(buf->data[0]);
 915         p = dtls1_set_message_header(s, p, SSL3_MT_CERTIFICATE, l, 0, l);
 916
 917         l+=DTLS1_HM_HEADER_LENGTH;
 918         return(l);
 919         }
 920
 921 int dtls1_read_failed(SSL *s, int code)
 922         {
 923         if ( code > 0)
 924                 {
 925                 fprintf( stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
 926                 return 1;
 927                 }
 928
 929         if (!dtls1_is_timer_expired(s))
 930                 {
 931                 /* not a timeout, none of our business,
 932                    let higher layers handle this.  in fact it's probably an error */
 933                 return code;
 934                 }
 935
 936         if ( ! SSL_in_init(s))  /* done, no need to send a retransmit */
 937                 {
 938                 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
 939                 return code;
 940                 }
 941
 942 #if 0 /* for now, each alert contains only one record number */
 943         item = pqueue_peek(state->rcvd_records);
 944         if ( item )
 945                 {
 946                 /* send an alert immediately for all the missing records */
 947                 }
 948         else
 949 #endif
 950
 951 #if 0  /* no more alert sending, just retransmit the last set of messages */
 952         if ( state->timeout.read_timeouts >= DTLS1_TMO_READ_COUNT)
 953                 ssl3_send_alert(s,SSL3_AL_WARNING,
 954                         DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
 955 #endif
 956
 957         return dtls1_handle_timeout(s);
 958         }
 959
 960 int
 961 dtls1_get_queue_priority(unsigned short seq, int is_ccs)
 962         {
 963         /* The index of the retransmission queue actually is the message sequence number,
 964          * since the queue only contains messages of a single handshake. However, the
 965          * ChangeCipherSpec has no message sequence number and so using only the sequence
 966          * will result in the CCS and Finished having the same index. To prevent this,
 967          * the sequence number is multiplied by 2. In case of a CCS 1 is subtracted.
 968          * This does not only differ CSS and Finished, it also maintains the order of the
 969          * index (important for priority queues) and fits in the unsigned short variable.
 970          */
 971         return seq * 2 - is_ccs;
 972         }
 973
 974 int
 975 dtls1_retransmit_buffered_messages(SSL *s)
 976         {
 977         pqueue sent = s->d1->sent_messages;
 978         piterator iter;
 979         pitem *item;
 980         hm_fragment *frag;
 981         int found = 0;
 982
 983         iter = pqueue_iterator(sent);
 984
 985         for ( item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter))
 986                 {
 987                 frag = (hm_fragment *)item->data;
 988                         if ( dtls1_retransmit_message(s,
 989                                 (unsigned short)dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs),
 990                                 0, &found) <= 0 && found)
 991                         {
 992                         fprintf(stderr, "dtls1_retransmit_message() failed\n");
 993                         return -1;
 994                         }
 995                 }
 996
 997         return 1;
 998         }
 999
1000 int
1001 dtls1_buffer_message(SSL *s, int is_ccs)
1002         {
1003         pitem *item;
1004         hm_fragment *frag;
1005         unsigned char seq64be[8];
1006
1007         /* this function is called immediately after a message has
1008          * been serialized */
1009         OPENSSL_assert(s->init_off == 0);
1010
1011         frag = dtls1_hm_fragment_new(s->init_num);
1012
1013         memcpy(frag->fragment, s->init_buf->data, s->init_num);
1014
1015         if ( is_ccs)
1016                 {
1017                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1018                                ((s->version==DTLS1_VERSION)?DTLS1_CCS_HEADER_LENGTH:3) == (unsigned int)s->init_num);
1019                 }
1020         else
1021                 {
1022                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1023                         DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
1024                 }
1025
1026         frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1027         frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1028         frag->msg_header.type = s->d1->w_msg_hdr.type;
1029         frag->msg_header.frag_off = 0;
1030         frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1031         frag->msg_header.is_ccs = is_ccs;
1032
1033         /* save current state*/
1034         frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
1035         frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
1036         frag->msg_header.saved_retransmit_state.compress = s->compress;
1037         frag->msg_header.saved_retransmit_state.session = s->session;
1038         frag->msg_header.saved_retransmit_state.epoch = s->d1->w_epoch;
1039
1040         memset(seq64be,0,sizeof(seq64be));
1041         seq64be[6] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1042                                                                                                                   frag->msg_header.is_ccs)>>8);
1043         seq64be[7] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1044                                                                                                                   frag->msg_header.is_ccs));
1045
1046         item = pitem_new(seq64be, frag);
1047         if ( item == NULL)
1048                 {
1049                 dtls1_hm_fragment_free(frag);
1050                 return 0;
1051                 }
1052
1053 #if 0
1054         fprintf( stderr, "buffered messge: \ttype = %xx\n", msg_buf->type);
1055         fprintf( stderr, "\t\t\t\t\tlen = %d\n", msg_buf->len);
1056         fprintf( stderr, "\t\t\t\t\tseq_num = %d\n", msg_buf->seq_num);
1057 #endif
1058
1059         pqueue_insert(s->d1->sent_messages, item);
1060         return 1;
1061         }
1062
1063 int
1064 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
1065         int *found)
1066         {
1067         int ret;
1068         /* XDTLS: for now assuming that read/writes are blocking */
1069         pitem *item;
1070         hm_fragment *frag ;
1071         unsigned long header_length;
1072         unsigned char seq64be[8];
1073         struct dtls1_retransmit_state saved_state;
1074         unsigned char save_write_sequence[8];
1075
1076         /*
1077           OPENSSL_assert(s->init_num == 0);
1078           OPENSSL_assert(s->init_off == 0);
1079          */
1080
1081         /* XDTLS:  the requested message ought to be found, otherwise error */
1082         memset(seq64be,0,sizeof(seq64be));
1083         seq64be[6] = (unsigned char)(seq>>8);
1084         seq64be[7] = (unsigned char)seq;
1085
1086         item = pqueue_find(s->d1->sent_messages, seq64be);
1087         if ( item == NULL)
1088                 {
1089                 fprintf(stderr, "retransmit:  message %d non-existant\n", seq);
1090                 *found = 0;
1091                 return 0;
1092                 }
1093
1094         *found = 1;
1095         frag = (hm_fragment *)item->data;
1096
1097         if ( frag->msg_header.is_ccs)
1098                 header_length = DTLS1_CCS_HEADER_LENGTH;
1099         else
1100                 header_length = DTLS1_HM_HEADER_LENGTH;
1101
1102         memcpy(s->init_buf->data, frag->fragment,
1103                 frag->msg_header.msg_len + header_length);
1104                 s->init_num = frag->msg_header.msg_len + header_length;
1105
1106         dtls1_set_message_header_int(s, frag->msg_header.type,
1107                 frag->msg_header.msg_len, frag->msg_header.seq, 0,
1108                 frag->msg_header.frag_len);
1109
1110         /* save current state */
1111         saved_state.enc_write_ctx = s->enc_write_ctx;
1112         saved_state.write_hash = s->write_hash;
1113         saved_state.compress = s->compress;
1114         saved_state.session = s->session;
1115         saved_state.epoch = s->d1->w_epoch;
1116         saved_state.epoch = s->d1->w_epoch;
1117
1118         s->d1->retransmitting = 1;
1119
1120         /* restore state in which the message was originally sent */
1121         s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
1122         s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
1123         s->compress = frag->msg_header.saved_retransmit_state.compress;
1124         s->session = frag->msg_header.saved_retransmit_state.session;
1125         s->d1->w_epoch = frag->msg_header.saved_retransmit_state.epoch;
1126
1127         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1128         {
1129                 memcpy(save_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1130                 memcpy(s->s3->write_sequence, s->d1->last_write_sequence, sizeof(s->s3->write_sequence));
1131         }
1132
1133         ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1134                                                  SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1135
1136         /* restore current state */
1137         s->enc_write_ctx = saved_state.enc_write_ctx;
1138         s->write_hash = saved_state.write_hash;
1139         s->compress = saved_state.compress;
1140         s->session = saved_state.session;
1141         s->d1->w_epoch = saved_state.epoch;
1142
1143         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1144         {
1145                 memcpy(s->d1->last_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1146                 memcpy(s->s3->write_sequence, save_write_sequence, sizeof(s->s3->write_sequence));
1147         }
1148
1149         s->d1->retransmitting = 0;
1150
1151         (void)BIO_flush(SSL_get_wbio(s));
1152         return ret;
1153         }
1154
1155 /* call this function when the buffered messages are no longer needed */
1156 void
1157 dtls1_clear_record_buffer(SSL *s)
1158         {
1159         pitem *item;
1160
1161         for(item = pqueue_pop(s->d1->sent_messages);
1162                 item != NULL; item = pqueue_pop(s->d1->sent_messages))
1163                 {
1164                 dtls1_hm_fragment_free((hm_fragment *)item->data);
1165                 pitem_free(item);
1166                 }
1167         }
1168
1169
1170 unsigned char *
1171 dtls1_set_message_header(SSL *s, unsigned char *p, unsigned char mt,
1172                         unsigned long len, unsigned long frag_off, unsigned long frag_len)
1173         {
1174         if ( frag_off == 0)
1175                 {
1176                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1177                 s->d1->next_handshake_write_seq++;
1178                 }
1179
1180         dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1181                 frag_off, frag_len);
1182
1183         return p += DTLS1_HM_HEADER_LENGTH;
1184         }
1185
1186
1187 /* don't actually do the writing, wait till the MTU has been retrieved */
1188 static void
1189 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1190                             unsigned long len, unsigned short seq_num, unsigned long frag_off,
1191                             unsigned long frag_len)
1192         {
1193         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1194
1195         msg_hdr->type = mt;
1196         msg_hdr->msg_len = len;
1197         msg_hdr->seq = seq_num;
1198         msg_hdr->frag_off = frag_off;
1199         msg_hdr->frag_len = frag_len;
1200         }
1201
1202 static void
1203 dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1204                         unsigned long frag_len)
1205         {
1206         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1207
1208         msg_hdr->frag_off = frag_off;
1209         msg_hdr->frag_len = frag_len;
1210         }
1211
1212 static unsigned char *
1213 dtls1_write_message_header(SSL *s, unsigned char *p)
1214         {
1215         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1216
1217         *p++ = msg_hdr->type;
1218         l2n3(msg_hdr->msg_len, p);
1219
1220         s2n(msg_hdr->seq, p);
1221         l2n3(msg_hdr->frag_off, p);
1222         l2n3(msg_hdr->frag_len, p);
1223
1224         return p;
1225         }
1226
1227 static unsigned int
1228 dtls1_min_mtu(void)
1229         {
1230         return (g_probable_mtu[(sizeof(g_probable_mtu) /
1231                 sizeof(g_probable_mtu[0])) - 1]);
1232         }
1233
1234 static unsigned int
1235 dtls1_guess_mtu(unsigned int curr_mtu)
1236         {
1237         unsigned int i;
1238
1239         if ( curr_mtu == 0 )
1240                 return g_probable_mtu[0] ;
1241
1242         for ( i = 0; i < sizeof(g_probable_mtu)/sizeof(g_probable_mtu[0]); i++)
1243                 if ( curr_mtu > g_probable_mtu[i])
1244                         return g_probable_mtu[i];
1245
1246         return curr_mtu;
1247         }
1248
1249 void
1250 dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1251         {
1252         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
1253         msg_hdr->type = *(data++);
1254         n2l3(data, msg_hdr->msg_len);
1255
1256         n2s(data, msg_hdr->seq);
1257         n2l3(data, msg_hdr->frag_off);
1258         n2l3(data, msg_hdr->frag_len);
1259         }
1260
1261 void
1262 dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
1263         {
1264         memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
1265
1266         ccs_hdr->type = *(data++);
1267         }