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;
 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         frag_off = 0;
 229         while( s->init_num)
 230                 {
 231                 curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) -
 232                         DTLS1_RT_HEADER_LENGTH;
 233
 234                 if ( curr_mtu <= DTLS1_HM_HEADER_LENGTH)
 235                         {
 236                         /* grr.. we could get an error if MTU picked was wrong */
 237                         ret = BIO_flush(SSL_get_wbio(s));
 238                         if ( ret <= 0)
 239                                 return ret;
 240                         curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH;
 241                         }
 242
 243                 if ( s->init_num > curr_mtu)
 244                         len = curr_mtu;
 245                 else
 246                         len = s->init_num;
 247
 248
 249                 /* XDTLS: this function is too long.  split out the CCS part */
 250                 if ( type == SSL3_RT_HANDSHAKE)
 251                         {
 252                         if ( s->init_off != 0)
 253                                 {
 254                                 OPENSSL_assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
 255                                 s->init_off -= DTLS1_HM_HEADER_LENGTH;
 256                                 s->init_num += DTLS1_HM_HEADER_LENGTH;
 257
 258                                 /* write atleast DTLS1_HM_HEADER_LENGTH bytes */
 259                                 if ( len <= DTLS1_HM_HEADER_LENGTH)
 260                                         len += DTLS1_HM_HEADER_LENGTH;
 261                                 }
 262
 263                         dtls1_fix_message_header(s, frag_off,
 264                                 len - DTLS1_HM_HEADER_LENGTH);
 265
 266                         dtls1_write_message_header(s, (unsigned char *)&s->init_buf->data[s->init_off]);
 267
 268                         OPENSSL_assert(len >= DTLS1_HM_HEADER_LENGTH);
 269                         }
 270
 271                 ret=dtls1_write_bytes(s,type,&s->init_buf->data[s->init_off],
 272                         len);
 273                 if (ret < 0)
 274                         {
 275                         /* might need to update MTU here, but we don't know
 276                          * which previous packet caused the failure -- so can't
 277                          * really retransmit anything.  continue as if everything
 278                          * is fine and wait for an alert to handle the
 279                          * retransmit
 280                          */
 281                         if ( BIO_ctrl(SSL_get_wbio(s),
 282                                 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL))
 283                                 s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
 284                                         BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
 285                         else
 286                                 return(-1);
 287                         }
 288                 else
 289                         {
 290
 291                         /* bad if this assert fails, only part of the handshake
 292                          * message got sent.  but why would this happen? */
 293                         OPENSSL_assert(len == (unsigned int)ret);
 294
 295                         if (type == SSL3_RT_HANDSHAKE && ! s->d1->retransmitting)
 296                                 {
 297                                 /* should not be done for 'Hello Request's, but in that case
 298                                  * we'll ignore the result anyway */
 299                                 unsigned char *p = (unsigned char *)&s->init_buf->data[s->init_off];
 300                                 const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
 301                                 int xlen;
 302
 303                                 if (frag_off == 0 && s->client_version != DTLS1_BAD_VER)
 304                                         {
 305                                         /* reconstruct message header is if it
 306                                          * is being sent in single fragment */
 307                                         *p++ = msg_hdr->type;
 308                                         l2n3(msg_hdr->msg_len,p);
 309                                         s2n (msg_hdr->seq,p);
 310                                         l2n3(0,p);
 311                                         l2n3(msg_hdr->msg_len,p);
 312                                         p  -= DTLS1_HM_HEADER_LENGTH;
 313                                         xlen = ret;
 314                                         }
 315                                 else
 316                                         {
 317                                         p  += DTLS1_HM_HEADER_LENGTH;
 318                                         xlen = ret - DTLS1_HM_HEADER_LENGTH;
 319                                         }
 320
 321                                 ssl3_finish_mac(s, p, xlen);
 322                                 }
 323
 324                         if (ret == s->init_num)
 325                                 {
 326                                 if (s->msg_callback)
 327                                         s->msg_callback(1, s->version, type, s->init_buf->data,
 328                                                 (size_t)(s->init_off + s->init_num), s,
 329                                                 s->msg_callback_arg);
 330
 331                                 s->init_off = 0;  /* done writing this message */
 332                                 s->init_num = 0;
 333
 334                                 return(1);
 335                                 }
 336                         s->init_off+=ret;
 337                         s->init_num-=ret;
 338                         frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
 339                         }
 340                 }
 341         return(0);
 342         }
 343
 344
 345 /* Obtain handshake message of message type 'mt' (any if mt == -1),
 346  * maximum acceptable body length 'max'.
 347  * Read an entire handshake message.  Handshake messages arrive in
 348  * fragments.
 349  */
 350 long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
 351         {
 352         int i, al;
 353         struct hm_header_st *msg_hdr;
 354
 355         /* s3->tmp is used to store messages that are unexpected, caused
 356          * by the absence of an optional handshake message */
 357         if (s->s3->tmp.reuse_message)
 358                 {
 359                 s->s3->tmp.reuse_message=0;
 360                 if ((mt >= 0) && (s->s3->tmp.message_type != mt))
 361                         {
 362                         al=SSL_AD_UNEXPECTED_MESSAGE;
 363                         SSLerr(SSL_F_DTLS1_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
 364                         goto f_err;
 365                         }
 366                 *ok=1;
 367                 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 368                 s->init_num = (int)s->s3->tmp.message_size;
 369                 return s->init_num;
 370                 }
 371
 372         msg_hdr = &s->d1->r_msg_hdr;
 373         do
 374                 {
 375                 if ( msg_hdr->frag_off == 0)
 376                         {
 377                         /* s->d1->r_message_header.msg_len = 0; */
 378                         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 379                         }
 380
 381                 i = dtls1_get_message_fragment(s, st1, stn, max, ok);
 382                 if ( i == DTLS1_HM_BAD_FRAGMENT ||
 383                         i == DTLS1_HM_FRAGMENT_RETRY)  /* bad fragment received */
 384                         continue;
 385                 else if ( i <= 0 && !*ok)
 386                         return i;
 387
 388                 /* Note that s->init_sum is used as a counter summing
 389                  * up fragments' lengths: as soon as they sum up to
 390                  * handshake packet length, we assume we have got all
 391                  * the fragments. Overlapping fragments would cause
 392                  * premature termination, so we don't expect overlaps.
 393                  * Well, handling overlaps would require something more
 394                  * drastic. Indeed, as it is now there is no way to
 395                  * tell if out-of-order fragment from the middle was
 396                  * the last. '>=' is the best/least we can do to control
 397                  * the potential damage caused by malformed overlaps. */
 398                 if ((unsigned int)s->init_num >= msg_hdr->msg_len)
 399                         {
 400                         unsigned char *p = (unsigned char *)s->init_buf->data;
 401                         unsigned long msg_len = msg_hdr->msg_len;
 402
 403                         /* reconstruct message header as if it was
 404                          * sent in single fragment */
 405                         *(p++) = msg_hdr->type;
 406                         l2n3(msg_len,p);
 407                         s2n (msg_hdr->seq,p);
 408                         l2n3(0,p);
 409                         l2n3(msg_len,p);
 410                         if (s->client_version != DTLS1_BAD_VER)
 411                                 p       -= DTLS1_HM_HEADER_LENGTH,
 412                                 msg_len += DTLS1_HM_HEADER_LENGTH;
 413
 414                         ssl3_finish_mac(s, p, msg_len);
 415                         if (s->msg_callback)
 416                                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 417                                         p, msg_len,
 418                                         s, s->msg_callback_arg);
 419
 420                         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 421
 422                         s->d1->handshake_read_seq++;
 423                         /* we just read a handshake message from the other side:
 424                          * this means that we don't need to retransmit of the
 425                          * buffered messages.
 426                          * XDTLS: may be able clear out this
 427                          * buffer a little sooner (i.e if an out-of-order
 428                          * handshake message/record is received at the record
 429                          * layer.
 430                          * XDTLS: exception is that the server needs to
 431                          * know that change cipher spec and finished messages
 432                          * have been received by the client before clearing this
 433                          * buffer.  this can simply be done by waiting for the
 434                          * first data  segment, but is there a better way?  */
 435                         dtls1_clear_record_buffer(s);
 436
 437                         s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 438                         return s->init_num;
 439                         }
 440                 else
 441                         msg_hdr->frag_off = i;
 442                 } while(1) ;
 443
 444 f_err:
 445         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 446         *ok = 0;
 447         return -1;
 448         }
 449
 450
 451 static int dtls1_preprocess_fragment(SSL *s,struct hm_header_st *msg_hdr,int max)
 452         {
 453         size_t frag_off,frag_len,msg_len;
 454
 455         msg_len  = msg_hdr->msg_len;
 456         frag_off = msg_hdr->frag_off;
 457         frag_len = msg_hdr->frag_len;
 458
 459         /* sanity checking */
 460         if ( (frag_off+frag_len) > msg_len)
 461                 {
 462                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 463                 return SSL_AD_ILLEGAL_PARAMETER;
 464                 }
 465
 466         if ( (frag_off+frag_len) > (unsigned long)max)
 467                 {
 468                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 469                 return SSL_AD_ILLEGAL_PARAMETER;
 470                 }
 471
 472         if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */
 473                 {
 474                 /* msg_len is limited to 2^24, but is effectively checked
 475                  * against max above */
 476                 if (!BUF_MEM_grow_clean(s->init_buf,(int)msg_len+DTLS1_HM_HEADER_LENGTH))
 477                         {
 478                         SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,ERR_R_BUF_LIB);
 479                         return SSL_AD_INTERNAL_ERROR;
 480                         }
 481
 482                 s->s3->tmp.message_size  = msg_len;
 483                 s->d1->r_msg_hdr.msg_len = msg_len;
 484                 s->s3->tmp.message_type  = msg_hdr->type;
 485                 s->d1->r_msg_hdr.type    = msg_hdr->type;
 486                 s->d1->r_msg_hdr.seq     = msg_hdr->seq;
 487                 }
 488         else if (msg_len != s->d1->r_msg_hdr.msg_len)
 489                 {
 490                 /* They must be playing with us! BTW, failure to enforce
 491                  * upper limit would open possibility for buffer overrun. */
 492                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 493                 return SSL_AD_ILLEGAL_PARAMETER;
 494                 }
 495
 496         return 0; /* no error */
 497         }
 498
 499
 500 static int
 501 dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok)
 502         {
 503         /* (0) check whether the desired fragment is available
 504          * if so:
 505          * (1) copy over the fragment to s->init_buf->data[]
 506          * (2) update s->init_num
 507          */
 508         pitem *item;
 509         hm_fragment *frag;
 510         int al;
 511
 512         *ok = 0;
 513         item = pqueue_peek(s->d1->buffered_messages);
 514         if ( item == NULL)
 515                 return 0;
 516
 517         frag = (hm_fragment *)item->data;
 518
 519         if ( s->d1->handshake_read_seq == frag->msg_header.seq)
 520                 {
 521                 pqueue_pop(s->d1->buffered_messages);
 522
 523                 al=dtls1_preprocess_fragment(s,&frag->msg_header,max);
 524
 525                 if (al==0) /* no alert */
 526                         {
 527                         unsigned char *p = (unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 528                         memcpy(&p[frag->msg_header.frag_off],
 529                                 frag->fragment,frag->msg_header.frag_len);
 530                         }
 531
 532                 dtls1_hm_fragment_free(frag);
 533                 pitem_free(item);
 534
 535                 if (al==0)
 536                         {
 537                         *ok = 1;
 538                         return frag->msg_header.frag_len;
 539                         }
 540
 541                 ssl3_send_alert(s,SSL3_AL_FATAL,al);
 542                 s->init_num = 0;
 543                 *ok = 0;
 544                 return -1;
 545                 }
 546         else
 547                 return 0;
 548         }
 549
 550
 551 static int
 552 dtls1_process_out_of_seq_message(SSL *s, struct hm_header_st* msg_hdr, int *ok)
 553 {
 554         int i=-1;
 555         hm_fragment *frag = NULL;
 556         pitem *item = NULL;
 557         PQ_64BIT seq64;
 558         unsigned long frag_len = msg_hdr->frag_len;
 559
 560         if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
 561                 goto err;
 562
 563         if (msg_hdr->seq <= s->d1->handshake_read_seq)
 564                 {
 565                 unsigned char devnull [256];
 566
 567                 while (frag_len)
 568                         {
 569                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 570                                 devnull,
 571                                 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
 572                         if (i<=0) goto err;
 573                         frag_len -= i;
 574                         }
 575                 }
 576
 577         if (frag_len)
 578         {
 579                 frag = dtls1_hm_fragment_new(frag_len);
 580                 if ( frag == NULL)
 581                         goto err;
 582
 583                 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 584
 585                 /* read the body of the fragment (header has already been read) */
 586                 i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 587                         frag->fragment,frag_len,0);
 588                 if (i<=0 || (unsigned long)i!=frag_len)
 589                         goto err;
 590
 591                 pq_64bit_init(&seq64);
 592                 pq_64bit_assign_word(&seq64, msg_hdr->seq);
 593
 594                 item = pitem_new(seq64, frag);
 595                 pq_64bit_free(&seq64);
 596                 if ( item == NULL)
 597                         goto err;
 598
 599                 pqueue_insert(s->d1->buffered_messages, item);
 600         }
 601
 602         return DTLS1_HM_FRAGMENT_RETRY;
 603
 604 err:
 605         if ( frag != NULL) dtls1_hm_fragment_free(frag);
 606         if ( item != NULL) OPENSSL_free(item);
 607         *ok = 0;
 608         return i;
 609         }
 610
 611
 612 static long
 613 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
 614         {
 615         unsigned char wire[DTLS1_HM_HEADER_LENGTH];
 616         unsigned long l, frag_off, frag_len;
 617         int i,al;
 618         struct hm_header_st msg_hdr;
 619
 620         /* see if we have the required fragment already */
 621         if ((frag_len = dtls1_retrieve_buffered_fragment(s,max,ok)) || *ok)
 622                 {
 623                 if (*ok)        s->init_num += frag_len;
 624                 return frag_len;
 625                 }
 626
 627         /* read handshake message header */
 628         i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,wire,
 629                 DTLS1_HM_HEADER_LENGTH, 0);
 630         if (i <= 0)     /* nbio, or an error */
 631                 {
 632                 s->rwstate=SSL_READING;
 633                 *ok = 0;
 634                 return i;
 635                 }
 636         OPENSSL_assert(i == DTLS1_HM_HEADER_LENGTH);
 637
 638         /* parse the message fragment header */
 639         dtls1_get_message_header(wire, &msg_hdr);
 640
 641         /*
 642          * if this is a future (or stale) message it gets buffered
 643          * (or dropped)--no further processing at this time
 644          */
 645         if ( msg_hdr.seq != s->d1->handshake_read_seq)
 646                 return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
 647
 648         l = msg_hdr.msg_len;
 649         frag_off = msg_hdr.frag_off;
 650         frag_len = msg_hdr.frag_len;
 651
 652         if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
 653                 wire[0] == SSL3_MT_HELLO_REQUEST)
 654                 {
 655                 /* The server may always send 'Hello Request' messages --
 656                  * we are doing a handshake anyway now, so ignore them
 657                  * if their format is correct. Does not count for
 658                  * 'Finished' MAC. */
 659                 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0)
 660                         {
 661                         if (s->msg_callback)
 662                                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 663                                         wire, DTLS1_HM_HEADER_LENGTH, s,
 664                                         s->msg_callback_arg);
 665
 666                         s->init_num = 0;
 667                         return dtls1_get_message_fragment(s, st1, stn,
 668                                 max, ok);
 669                         }
 670                 else /* Incorrectly formated Hello request */
 671                         {
 672                         al=SSL_AD_UNEXPECTED_MESSAGE;
 673                         SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 674                         goto f_err;
 675                         }
 676                 }
 677
 678         if ((al=dtls1_preprocess_fragment(s,&msg_hdr,max)))
 679                 goto f_err;
 680
 681         /* XDTLS:  ressurect this when restart is in place */
 682         s->state=stn;
 683
 684         if ( frag_len > 0)
 685                 {
 686                 unsigned char *p=(unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 687
 688                 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 689                         &p[frag_off],frag_len,0);
 690                 /* XDTLS:  fix this--message fragments cannot span multiple packets */
 691                 if (i <= 0)
 692                         {
 693                         s->rwstate=SSL_READING;
 694                         *ok = 0;
 695                         return i;
 696                         }
 697                 }
 698         else
 699                 i = 0;
 700
 701         /* XDTLS:  an incorrectly formatted fragment should cause the
 702          * handshake to fail */
 703         OPENSSL_assert(i == (int)frag_len);
 704
 705         *ok = 1;
 706
 707         /* Note that s->init_num is *not* used as current offset in
 708          * s->init_buf->data, but as a counter summing up fragments'
 709          * lengths: as soon as they sum up to handshake packet
 710          * length, we assume we have got all the fragments. */
 711         s->init_num += frag_len;
 712         return frag_len;
 713
 714 f_err:
 715         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 716         s->init_num = 0;
 717
 718         *ok=0;
 719         return(-1);
 720         }
 721
 722 int dtls1_send_finished(SSL *s, int a, int b, const char *sender, int slen)
 723         {
 724         unsigned char *p,*d;
 725         int i;
 726         unsigned long l;
 727
 728         if (s->state == a)
 729                 {
 730                 d=(unsigned char *)s->init_buf->data;
 731                 p= &(d[DTLS1_HM_HEADER_LENGTH]);
 732
 733                 i=s->method->ssl3_enc->final_finish_mac(s,
 734                         &(s->s3->finish_dgst1),
 735                         &(s->s3->finish_dgst2),
 736                         sender,slen,s->s3->tmp.finish_md);
 737                 s->s3->tmp.finish_md_len = i;
 738                 memcpy(p, s->s3->tmp.finish_md, i);
 739                 p+=i;
 740                 l=i;
 741
 742 #ifdef OPENSSL_SYS_WIN16
 743                 /* MSVC 1.5 does not clear the top bytes of the word unless
 744                  * I do this.
 745                  */
 746                 l&=0xffff;
 747 #endif
 748
 749                 d = dtls1_set_message_header(s, d, SSL3_MT_FINISHED, l, 0, l);
 750                 s->init_num=(int)l+DTLS1_HM_HEADER_LENGTH;
 751                 s->init_off=0;
 752
 753                 /* buffer the message to handle re-xmits */
 754                 dtls1_buffer_message(s, 0);
 755
 756                 s->state=b;
 757                 }
 758
 759         /* SSL3_ST_SEND_xxxxxx_HELLO_B */
 760         return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
 761         }
 762
 763 /* for these 2 messages, we need to
 764  * ssl->enc_read_ctx                    re-init
 765  * ssl->s3->read_sequence               zero
 766  * ssl->s3->read_mac_secret             re-init
 767  * ssl->session->read_sym_enc           assign
 768  * ssl->session->read_compression       assign
 769  * ssl->session->read_hash              assign
 770  */
 771 int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
 772         {
 773         unsigned char *p;
 774
 775         if (s->state == a)
 776                 {
 777                 p=(unsigned char *)s->init_buf->data;
 778                 *p++=SSL3_MT_CCS;
 779                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
 780                 s->init_num=DTLS1_CCS_HEADER_LENGTH;
 781
 782                 if (s->client_version == DTLS1_BAD_VER)
 783                         {
 784                         s->d1->next_handshake_write_seq++;
 785                         s2n(s->d1->handshake_write_seq,p);
 786                         s->init_num+=2;
 787                         }
 788
 789                 s->init_off=0;
 790
 791                 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
 792                         s->d1->handshake_write_seq, 0, 0);
 793
 794                 /* buffer the message to handle re-xmits */
 795                 dtls1_buffer_message(s, 1);
 796
 797                 s->state=b;
 798                 }
 799
 800         /* SSL3_ST_CW_CHANGE_B */
 801         return(dtls1_do_write(s,SSL3_RT_CHANGE_CIPHER_SPEC));
 802         }
 803
 804 unsigned long dtls1_output_cert_chain(SSL *s, X509 *x)
 805         {
 806         unsigned char *p;
 807         int n,i;
 808         unsigned long l= 3 + DTLS1_HM_HEADER_LENGTH;
 809         BUF_MEM *buf;
 810         X509_STORE_CTX xs_ctx;
 811         X509_OBJECT obj;
 812
 813         /* TLSv1 sends a chain with nothing in it, instead of an alert */
 814         buf=s->init_buf;
 815         if (!BUF_MEM_grow_clean(buf,10))
 816                 {
 817                 SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
 818                 return(0);
 819                 }
 820         if (x != NULL)
 821                 {
 822                 if(!X509_STORE_CTX_init(&xs_ctx,s->ctx->cert_store,NULL,NULL))
 823                         {
 824                         SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_X509_LIB);
 825                         return(0);
 826                         }
 827
 828                 for (;;)
 829                         {
 830                         n=i2d_X509(x,NULL);
 831                         if (!BUF_MEM_grow_clean(buf,(int)(n+l+3)))
 832                                 {
 833                                 SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
 834                                 return(0);
 835                                 }
 836                         p=(unsigned char *)&(buf->data[l]);
 837                         l2n3(n,p);
 838                         i2d_X509(x,&p);
 839                         l+=n+3;
 840                         if (X509_NAME_cmp(X509_get_subject_name(x),
 841                                 X509_get_issuer_name(x)) == 0) break;
 842
 843                         i=X509_STORE_get_by_subject(&xs_ctx,X509_LU_X509,
 844                                 X509_get_issuer_name(x),&obj);
 845                         if (i <= 0) break;
 846                         x=obj.data.x509;
 847                         /* Count is one too high since the X509_STORE_get uped the
 848                          * ref count */
 849                         X509_free(x);
 850                         }
 851
 852                 X509_STORE_CTX_cleanup(&xs_ctx);
 853                 }
 854
 855         /* Thawte special :-) */
 856         if (s->ctx->extra_certs != NULL)
 857         for (i=0; i<sk_X509_num(s->ctx->extra_certs); i++)
 858                 {
 859                 x=sk_X509_value(s->ctx->extra_certs,i);
 860                 n=i2d_X509(x,NULL);
 861                 if (!BUF_MEM_grow_clean(buf,(int)(n+l+3)))
 862                         {
 863                         SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
 864                         return(0);
 865                         }
 866                 p=(unsigned char *)&(buf->data[l]);
 867                 l2n3(n,p);
 868                 i2d_X509(x,&p);
 869                 l+=n+3;
 870                 }
 871
 872         l-= (3 + DTLS1_HM_HEADER_LENGTH);
 873
 874         p=(unsigned char *)&(buf->data[DTLS1_HM_HEADER_LENGTH]);
 875         l2n3(l,p);
 876         l+=3;
 877         p=(unsigned char *)&(buf->data[0]);
 878         p = dtls1_set_message_header(s, p, SSL3_MT_CERTIFICATE, l, 0, l);
 879
 880         l+=DTLS1_HM_HEADER_LENGTH;
 881         return(l);
 882         }
 883
 884 int dtls1_read_failed(SSL *s, int code)
 885         {
 886         DTLS1_STATE *state;
 887         BIO *bio;
 888         int send_alert = 0;
 889
 890         if ( code > 0)
 891                 {
 892                 fprintf( stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
 893                 return 1;
 894                 }
 895
 896         bio = SSL_get_rbio(s);
 897         if ( ! BIO_dgram_recv_timedout(bio))
 898                 {
 899                 /* not a timeout, none of our business,
 900                    let higher layers handle this.  in fact it's probably an error */
 901                 return code;
 902                 }
 903
 904         if ( ! SSL_in_init(s))  /* done, no need to send a retransmit */
 905                 {
 906                 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
 907                 return code;
 908                 }
 909
 910         state = s->d1;
 911         state->timeout.num_alerts++;
 912         if ( state->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT)
 913                 {
 914                 /* fail the connection, enough alerts have been sent */
 915                 SSLerr(SSL_F_DTLS1_READ_FAILED,SSL_R_READ_TIMEOUT_EXPIRED);
 916                 return 0;
 917                 }
 918
 919         state->timeout.read_timeouts++;
 920         if ( state->timeout.read_timeouts > DTLS1_TMO_READ_COUNT)
 921                 {
 922                 send_alert = 1;
 923                 state->timeout.read_timeouts = 1;
 924                 }
 925
 926
 927 #if 0 /* for now, each alert contains only one record number */
 928         item = pqueue_peek(state->rcvd_records);
 929         if ( item )
 930                 {
 931                 /* send an alert immediately for all the missing records */
 932                 }
 933         else
 934 #endif
 935
 936 #if 0  /* no more alert sending, just retransmit the last set of messages */
 937                 if ( send_alert)
 938                         ssl3_send_alert(s,SSL3_AL_WARNING,
 939                                 DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
 940 #endif
 941
 942         return dtls1_retransmit_buffered_messages(s) ;
 943         }
 944
 945 int
 946 dtls1_get_queue_priority(unsigned short seq, int is_ccs)
 947         {
 948         /* The index of the retransmission queue actually is the message sequence number,
 949          * since the queue only contains messages of a single handshake. However, the
 950          * ChangeCipherSpec has no message sequence number and so using only the sequence
 951          * will result in the CCS and Finished having the same index. To prevent this,
 952          * the sequence number is multiplied by 2. In case of a CCS 1 is subtracted.
 953          * This does not only differ CSS and Finished, it also maintains the order of the
 954          * index (important for priority queues) and fits in the unsigned short variable.
 955          */
 956         return seq * 2 - is_ccs;
 957         }
 958
 959 int
 960 dtls1_retransmit_buffered_messages(SSL *s)
 961         {
 962         pqueue sent = s->d1->sent_messages;
 963         piterator iter;
 964         pitem *item;
 965         hm_fragment *frag;
 966         int found = 0;
 967
 968         iter = pqueue_iterator(sent);
 969
 970         for ( item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter))
 971                 {
 972                 frag = (hm_fragment *)item->data;
 973                         if ( dtls1_retransmit_message(s,
 974                                 dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs),
 975                                 0, &found) <= 0 && found)
 976                         {
 977                         fprintf(stderr, "dtls1_retransmit_message() failed\n");
 978                         return -1;
 979                         }
 980                 }
 981
 982         return 1;
 983         }
 984
 985 int
 986 dtls1_buffer_message(SSL *s, int is_ccs)
 987         {
 988         pitem *item;
 989         hm_fragment *frag;
 990         PQ_64BIT seq64;
 991
 992         /* this function is called immediately after a message has
 993          * been serialized */
 994         OPENSSL_assert(s->init_off == 0);
 995
 996         frag = dtls1_hm_fragment_new(s->init_num);
 997
 998         memcpy(frag->fragment, s->init_buf->data, s->init_num);
 999
1000         if ( is_ccs)
1001                 {
1002                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1003                         DTLS1_CCS_HEADER_LENGTH <= (unsigned int)s->init_num);
1004                 }
1005         else
1006                 {
1007                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1008                         DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
1009                 }
1010
1011         frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1012         frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1013         frag->msg_header.type = s->d1->w_msg_hdr.type;
1014         frag->msg_header.frag_off = 0;
1015         frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1016         frag->msg_header.is_ccs = is_ccs;
1017
1018         /* save current state*/
1019         frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
1020         frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
1021         frag->msg_header.saved_retransmit_state.compress = s->compress;
1022         frag->msg_header.saved_retransmit_state.session = s->session;
1023         frag->msg_header.saved_retransmit_state.epoch = s->d1->w_epoch;
1024
1025         pq_64bit_init(&seq64);
1026
1027         pq_64bit_assign_word(&seq64,
1028                                                  dtls1_get_queue_priority(frag->msg_header.seq,
1029                                                                                                   frag->msg_header.is_ccs));
1030
1031         item = pitem_new(seq64, frag);
1032         pq_64bit_free(&seq64);
1033         if ( item == NULL)
1034                 {
1035                 dtls1_hm_fragment_free(frag);
1036                 return 0;
1037                 }
1038
1039 #if 0
1040         fprintf( stderr, "buffered messge: \ttype = %xx\n", msg_buf->type);
1041         fprintf( stderr, "\t\t\t\t\tlen = %d\n", msg_buf->len);
1042         fprintf( stderr, "\t\t\t\t\tseq_num = %d\n", msg_buf->seq_num);
1043 #endif
1044
1045         pqueue_insert(s->d1->sent_messages, item);
1046         return 1;
1047         }
1048
1049 int
1050 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
1051         int *found)
1052         {
1053         int ret;
1054         /* XDTLS: for now assuming that read/writes are blocking */
1055         pitem *item;
1056         hm_fragment *frag ;
1057         unsigned long header_length;
1058         PQ_64BIT seq64;
1059         struct dtls1_retransmit_state saved_state;
1060         unsigned char save_write_sequence[8];
1061
1062         /*
1063           OPENSSL_assert(s->init_num == 0);
1064           OPENSSL_assert(s->init_off == 0);
1065          */
1066
1067         /* XDTLS:  the requested message ought to be found, otherwise error */
1068         pq_64bit_init(&seq64);
1069         pq_64bit_assign_word(&seq64, seq);
1070
1071         item = pqueue_find(s->d1->sent_messages, seq64);
1072         pq_64bit_free(&seq64);
1073         if ( item == NULL)
1074                 {
1075                 fprintf(stderr, "retransmit:  message %d non-existant\n", seq);
1076                 *found = 0;
1077                 return 0;
1078                 }
1079
1080         *found = 1;
1081         frag = (hm_fragment *)item->data;
1082
1083         if ( frag->msg_header.is_ccs)
1084                 header_length = DTLS1_CCS_HEADER_LENGTH;
1085         else
1086                 header_length = DTLS1_HM_HEADER_LENGTH;
1087
1088         memcpy(s->init_buf->data, frag->fragment,
1089                 frag->msg_header.msg_len + header_length);
1090                 s->init_num = frag->msg_header.msg_len + header_length;
1091
1092         dtls1_set_message_header_int(s, frag->msg_header.type,
1093                 frag->msg_header.msg_len, frag->msg_header.seq, 0,
1094                 frag->msg_header.frag_len);
1095
1096         /* save current state */
1097         saved_state.enc_write_ctx = s->enc_write_ctx;
1098         saved_state.write_hash = s->write_hash;
1099         saved_state.compress = s->compress;
1100         saved_state.session = s->session;
1101         saved_state.epoch = s->d1->w_epoch;
1102         saved_state.epoch = s->d1->w_epoch;
1103
1104         s->d1->retransmitting = 1;
1105
1106         /* restore state in which the message was originally sent */
1107         s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
1108         s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
1109         s->compress = frag->msg_header.saved_retransmit_state.compress;
1110         s->session = frag->msg_header.saved_retransmit_state.session;
1111         s->d1->w_epoch = frag->msg_header.saved_retransmit_state.epoch;
1112
1113         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1114         {
1115                 memcpy(save_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1116                 memcpy(s->s3->write_sequence, s->d1->last_write_sequence, sizeof(s->s3->write_sequence));
1117         }
1118
1119         ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1120                                                  SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1121
1122         /* restore current state */
1123         s->enc_write_ctx = saved_state.enc_write_ctx;
1124         s->write_hash = saved_state.write_hash;
1125         s->compress = saved_state.compress;
1126         s->session = saved_state.session;
1127         s->d1->w_epoch = saved_state.epoch;
1128
1129         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1130         {
1131                 memcpy(s->d1->last_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1132                 memcpy(s->s3->write_sequence, save_write_sequence, sizeof(s->s3->write_sequence));
1133         }
1134
1135         s->d1->retransmitting = 0;
1136
1137         (void)BIO_flush(SSL_get_wbio(s));
1138         return ret;
1139         }
1140
1141 /* call this function when the buffered messages are no longer needed */
1142 void
1143 dtls1_clear_record_buffer(SSL *s)
1144         {
1145         pitem *item;
1146
1147         for(item = pqueue_pop(s->d1->sent_messages);
1148                 item != NULL; item = pqueue_pop(s->d1->sent_messages))
1149                 {
1150                 dtls1_hm_fragment_free((hm_fragment *)item->data);
1151                 pitem_free(item);
1152                 }
1153         }
1154
1155
1156 unsigned char *
1157 dtls1_set_message_header(SSL *s, unsigned char *p, unsigned char mt,
1158                         unsigned long len, unsigned long frag_off, unsigned long frag_len)
1159         {
1160         if ( frag_off == 0)
1161                 {
1162                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1163                 s->d1->next_handshake_write_seq++;
1164                 }
1165
1166         dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1167                 frag_off, frag_len);
1168
1169         return p += DTLS1_HM_HEADER_LENGTH;
1170         }
1171
1172
1173 /* don't actually do the writing, wait till the MTU has been retrieved */
1174 static void
1175 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1176                             unsigned long len, unsigned short seq_num, unsigned long frag_off,
1177                             unsigned long frag_len)
1178         {
1179         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1180
1181         msg_hdr->type = mt;
1182         msg_hdr->msg_len = len;
1183         msg_hdr->seq = seq_num;
1184         msg_hdr->frag_off = frag_off;
1185         msg_hdr->frag_len = frag_len;
1186         }
1187
1188 static void
1189 dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1190                         unsigned long frag_len)
1191         {
1192         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1193
1194         msg_hdr->frag_off = frag_off;
1195         msg_hdr->frag_len = frag_len;
1196         }
1197
1198 static unsigned char *
1199 dtls1_write_message_header(SSL *s, unsigned char *p)
1200         {
1201         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1202
1203         *p++ = msg_hdr->type;
1204         l2n3(msg_hdr->msg_len, p);
1205
1206         s2n(msg_hdr->seq, p);
1207         l2n3(msg_hdr->frag_off, p);
1208         l2n3(msg_hdr->frag_len, p);
1209
1210         return p;
1211         }
1212
1213 static unsigned int
1214 dtls1_min_mtu(void)
1215         {
1216         return (g_probable_mtu[(sizeof(g_probable_mtu) /
1217                 sizeof(g_probable_mtu[0])) - 1]);
1218         }
1219
1220 static unsigned int
1221 dtls1_guess_mtu(unsigned int curr_mtu)
1222         {
1223         size_t i;
1224
1225         if ( curr_mtu == 0 )
1226                 return g_probable_mtu[0] ;
1227
1228         for ( i = 0; i < sizeof(g_probable_mtu)/sizeof(g_probable_mtu[0]); i++)
1229                 if ( curr_mtu > g_probable_mtu[i])
1230                         return g_probable_mtu[i];
1231
1232         return curr_mtu;
1233         }
1234
1235 void
1236 dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1237         {
1238         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
1239         msg_hdr->type = *(data++);
1240         n2l3(data, msg_hdr->msg_len);
1241
1242         n2s(data, msg_hdr->seq);
1243         n2l3(data, msg_hdr->frag_off);
1244         n2l3(data, msg_hdr->frag_len);
1245         }
1246
1247 void
1248 dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
1249         {
1250         memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
1251
1252         ccs_hdr->type = *(data++);
1253         }