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 int dtls1_retransmit_buffered_messages(SSL *s);
 140 static long dtls1_get_message_fragment(SSL *s, int st1, int stn,
 141     long max, int *ok);
 142 static void dtls1_process_handshake_fragment(SSL *s, int frag_len);
 143
 144 static hm_fragment *
 145 dtls1_hm_fragment_new(unsigned long frag_len)
 146     {
 147     hm_fragment *frag = NULL;
 148     unsigned char *buf = NULL;
 149
 150     frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment));
 151     if ( frag == NULL)
 152         return NULL;
 153
 154     buf = (unsigned char *)OPENSSL_malloc(frag_len
 155         + DTLS1_HM_HEADER_LENGTH);
 156     if ( buf == NULL)
 157         {
 158         OPENSSL_free(frag);
 159         return NULL;
 160         }
 161
 162     frag->fragment = buf;
 163
 164     return frag;
 165     }
 166
 167 static void
 168 dtls1_hm_fragment_free(hm_fragment *frag)
 169     {
 170     OPENSSL_free(frag->fragment);
 171     OPENSSL_free(frag);
 172     }
 173
 174 /* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
 175 int dtls1_do_write(SSL *s, int type)
 176         {
 177         int ret;
 178         int curr_mtu;
 179         unsigned int len, frag_off;
 180
 181         /* AHA!  Figure out the MTU, and stick to the right size */
 182         if ( ! (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
 183         {
 184                 s->d1->mtu =
 185                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
 186
 187                 /* I've seen the kernel return bogus numbers when it doesn't know
 188                  * (initial write), so just make sure we have a reasonable number */
 189                 if ( s->d1->mtu < dtls1_min_mtu())
 190                         {
 191                         s->d1->mtu = 0;
 192                         s->d1->mtu = dtls1_guess_mtu(s->d1->mtu);
 193                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
 194                                 s->d1->mtu, NULL);
 195                         }
 196                 }
 197 #if 0
 198         mtu = s->d1->mtu;
 199
 200         fprintf(stderr, "using MTU = %d\n", mtu);
 201
 202         mtu -= (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 203
 204         curr_mtu = mtu - BIO_wpending(SSL_get_wbio(s));
 205
 206         if ( curr_mtu > 0)
 207                 mtu = curr_mtu;
 208         else if ( ( ret = BIO_flush(SSL_get_wbio(s))) <= 0)
 209                 return ret;
 210
 211         if ( BIO_wpending(SSL_get_wbio(s)) + s->init_num >= mtu)
 212                 {
 213                 ret = BIO_flush(SSL_get_wbio(s));
 214                 if ( ret <= 0)
 215                         return ret;
 216                 mtu = s->d1->mtu - (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 217                 }
 218
 219         OPENSSL_assert(mtu > 0);  /* should have something reasonable now */
 220
 221 #endif
 222
 223         if ( s->init_off == 0  && type == SSL3_RT_HANDSHAKE)
 224                 OPENSSL_assert(s->init_num ==
 225                         (int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH);
 226
 227         frag_off = 0;
 228         while( s->init_num)
 229                 {
 230                 curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) -
 231                         DTLS1_RT_HEADER_LENGTH;
 232
 233                 if ( curr_mtu <= DTLS1_HM_HEADER_LENGTH)
 234                         {
 235                         /* grr.. we could get an error if MTU picked was wrong */
 236                         ret = BIO_flush(SSL_get_wbio(s));
 237                         if ( ret <= 0)
 238                                 return ret;
 239                         curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH;
 240                         }
 241
 242                 if ( s->init_num > curr_mtu)
 243                         len = curr_mtu;
 244                 else
 245                         len = s->init_num;
 246
 247
 248                 /* XDTLS: this function is too long.  split out the CCS part */
 249                 if ( type == SSL3_RT_HANDSHAKE)
 250                         {
 251                         if ( s->init_off != 0)
 252                                 {
 253                                 OPENSSL_assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
 254                                 s->init_off -= DTLS1_HM_HEADER_LENGTH;
 255                                 s->init_num += DTLS1_HM_HEADER_LENGTH;
 256
 257                 /* write atleast DTLS1_HM_HEADER_LENGTH bytes */
 258                                 if ( len <= DTLS1_HM_HEADER_LENGTH)
 259                                         len += DTLS1_HM_HEADER_LENGTH;
 260                                 }
 261
 262                         dtls1_fix_message_header(s, frag_off,
 263                                 len - DTLS1_HM_HEADER_LENGTH);
 264
 265                         dtls1_write_message_header(s, (unsigned char *)&s->init_buf->data[s->init_off]);
 266
 267                         OPENSSL_assert(len >= DTLS1_HM_HEADER_LENGTH);
 268                         }
 269
 270                 ret=dtls1_write_bytes(s,type,&s->init_buf->data[s->init_off],
 271                         len);
 272                 if (ret < 0)
 273                         {
 274                         /* might need to update MTU here, but we don't know
 275                          * which previous packet caused the failure -- so can't
 276                          * really retransmit anything.  continue as if everything
 277                          * is fine and wait for an alert to handle the
 278                          * retransmit
 279                          */
 280                         if ( BIO_ctrl(SSL_get_wbio(s),
 281                                 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL))
 282                                 s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
 283                                         BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
 284                         else
 285                                 return(-1);
 286                         }
 287                 else
 288                         {
 289
 290                         /* bad if this assert fails, only part of the handshake
 291                          * message got sent.  but why would this happen? */
 292                         OPENSSL_assert(len == (unsigned int)ret);
 293
 294                         if (type == SSL3_RT_HANDSHAKE && ! s->d1->retransmitting)
 295                                 /* should not be done for 'Hello Request's, but in that case
 296                                  * we'll ignore the result anyway */
 297                                 ssl3_finish_mac(s,
 298                                         (unsigned char *)&s->init_buf->data[s->init_off +
 299                                                 DTLS1_HM_HEADER_LENGTH], ret - DTLS1_HM_HEADER_LENGTH);
 300
 301                         if (ret == s->init_num)
 302                                 {
 303                                 if (s->msg_callback)
 304                                         s->msg_callback(1, s->version, type, s->init_buf->data,
 305                                                 (size_t)(s->init_off + s->init_num), s,
 306                                                 s->msg_callback_arg);
 307
 308                                 s->init_off = 0;  /* done writing this message */
 309                                 s->init_num = 0;
 310
 311                                 return(1);
 312                                 }
 313                         s->init_off+=ret;
 314                         s->init_num-=ret;
 315                         frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
 316                         }
 317                 }
 318         return(0);
 319         }
 320
 321
 322 /* Obtain handshake message of message type 'mt' (any if mt == -1),
 323  * maximum acceptable body length 'max'.
 324  * Read an entire handshake message.  Handshake messages arrive in
 325  * fragments.
 326  */
 327 long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
 328         {
 329         int i, al;
 330
 331         /* s3->tmp is used to store messages that are unexpected, caused
 332          * by the absence of an optional handshake message */
 333         if (s->s3->tmp.reuse_message)
 334                 {
 335                 s->s3->tmp.reuse_message=0;
 336                 if ((mt >= 0) && (s->s3->tmp.message_type != mt))
 337                         {
 338                         al=SSL_AD_UNEXPECTED_MESSAGE;
 339                         SSLerr(SSL_F_DTLS1_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
 340                         goto f_err;
 341                         }
 342                 *ok=1;
 343                 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 344                 s->init_num = (int)s->s3->tmp.message_size;
 345                 return s->init_num;
 346                 }
 347
 348         do
 349                 {
 350                 if ( s->d1->r_msg_hdr.frag_off == 0)
 351                         {
 352                         /* s->d1->r_message_header.msg_len = 0; */
 353                         memset(&(s->d1->r_msg_hdr), 0x00, sizeof(struct hm_header_st));
 354                         }
 355
 356                 i = dtls1_get_message_fragment(s, st1, stn, max, ok);
 357                 if ( i == DTLS1_HM_BAD_FRAGMENT ||
 358             i == DTLS1_HM_FRAGMENT_RETRY)  /* bad fragment received */
 359                         continue;
 360                 else if ( i <= 0 && !*ok)
 361                         return i;
 362
 363                 if (s->d1->r_msg_hdr.msg_len == (unsigned int)s->init_num - DTLS1_HM_HEADER_LENGTH)
 364                         {
 365                         memset(&(s->d1->r_msg_hdr), 0x00, sizeof(struct hm_header_st));
 366
 367                         s->d1->handshake_read_seq++;
 368                         /* we just read a handshake message from the other side:
 369                          * this means that we don't need to retransmit of the
 370                          * buffered messages.
 371                          * XDTLS: may be able clear out this
 372                          * buffer a little sooner (i.e if an out-of-order
 373                          * handshake message/record is received at the record
 374                          * layer.
 375                          * XDTLS: exception is that the server needs to
 376                          * know that change cipher spec and finished messages
 377                          * have been received by the client before clearing this
 378                          * buffer.  this can simply be done by waiting for the
 379                          * first data  segment, but is there a better way?  */
 380                         dtls1_clear_record_buffer(s);
 381
 382             s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 383                         return s->init_num - DTLS1_HM_HEADER_LENGTH;
 384                         }
 385                 else
 386                         s->d1->r_msg_hdr.frag_off = i;
 387                 } while(1) ;
 388
 389 f_err:
 390         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 391         *ok = 0;
 392         return -1;
 393         }
 394
 395
 396 static int
 397 dtls1_retrieve_buffered_fragment(SSL *s, unsigned long *copied)
 398     {
 399     /* (0) check whether the desired fragment is available
 400      * if so:
 401      * (1) copy over the fragment to s->init_buf->data[]
 402      * (2) update s->init_num
 403      */
 404     pitem *item;
 405     hm_fragment *frag;
 406     unsigned long overlap;
 407     unsigned char *p;
 408
 409     item = pqueue_peek(s->d1->buffered_messages);
 410     if ( item == NULL)
 411         return 0;
 412
 413     frag = (hm_fragment *)item->data;
 414
 415     if ( s->d1->handshake_read_seq == frag->msg_header.seq &&
 416         frag->msg_header.frag_off <= (unsigned int)s->init_num - DTLS1_HM_HEADER_LENGTH)
 417         {
 418         pqueue_pop(s->d1->buffered_messages);
 419         overlap = s->init_num - DTLS1_HM_HEADER_LENGTH
 420             - frag->msg_header.frag_off;
 421
 422         p = frag->fragment;
 423
 424         memcpy(&s->init_buf->data[s->init_num],
 425             p + DTLS1_HM_HEADER_LENGTH + overlap,
 426             frag->msg_header.frag_len - overlap);
 427
 428         OPENSSL_free(frag->fragment);
 429         OPENSSL_free(frag);
 430         pitem_free(item);
 431
 432         *copied = frag->msg_header.frag_len - overlap;
 433         return *copied;
 434         }
 435     else
 436         return 0;
 437     }
 438
 439
 440 static int
 441 dtls1_buffer_handshake_fragment(SSL *s, struct hm_header_st* msg_hdr)
 442 {
 443     hm_fragment *frag = NULL;
 444     pitem *item = NULL;
 445     unsigned char seq64be[8];
 446
 447     frag = dtls1_hm_fragment_new(msg_hdr->frag_len);
 448     if ( frag == NULL)
 449         goto err;
 450
 451     memcpy(frag->fragment, &(s->init_buf->data[s->init_num]),
 452         msg_hdr->frag_len + DTLS1_HM_HEADER_LENGTH);
 453
 454     memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 455
 456     memset(seq64be,0,sizeof(seq64be));
 457     seq64be[6] = (unsigned char)(msg_hdr->seq>>8);
 458     seq64be[7] = (unsigned char)(msg_hdr->seq);
 459
 460     item = pitem_new(seq64be, frag);
 461     if ( item == NULL)
 462         goto err;
 463
 464     pqueue_insert(s->d1->buffered_messages, item);
 465     return 1;
 466
 467 err:
 468     if ( frag != NULL) dtls1_hm_fragment_free(frag);
 469     if ( item != NULL) OPENSSL_free(item);
 470     return 0;
 471 }
 472
 473
 474 static void
 475 dtls1_process_handshake_fragment(SSL *s, int frag_len)
 476     {
 477     unsigned char *p;
 478
 479     p = (unsigned char *)s->init_buf->data;
 480
 481         ssl3_finish_mac(s, &p[s->init_num - frag_len], frag_len);
 482     }
 483
 484
 485 static int
 486 dtls1_process_out_of_seq_message(SSL *s, struct hm_header_st *msg_hdr, int *ok)
 487     {
 488     int i;
 489     unsigned char *p;
 490
 491     /* make sure there's enough room to read this fragment */
 492     if ( (int)msg_hdr->frag_len && !BUF_MEM_grow_clean(s->init_buf,
 493              (int)msg_hdr->frag_len + DTLS1_HM_HEADER_LENGTH + s->init_num))
 494         {
 495         SSLerr(SSL_F_DTLS1_PROCESS_OUT_OF_SEQ_MESSAGE,ERR_R_BUF_LIB);
 496         goto err;
 497         }
 498
 499     p = (unsigned char *)s->init_buf->data;
 500
 501     /* read the body of the fragment (header has already been read */
 502     if ( msg_hdr->frag_len > 0)
 503                 {
 504                 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 505             &p[s->init_num],
 506             msg_hdr->frag_len,0);
 507                 if (i <= 0)
 508                         {
 509                         *ok = 0;
 510                         return i;
 511                         }
 512                 }
 513
 514     if ( msg_hdr->seq > s->d1->handshake_read_seq)
 515         dtls1_buffer_handshake_fragment(s, msg_hdr);
 516     else
 517         OPENSSL_assert(msg_hdr->seq < s->d1->handshake_read_seq);
 518
 519     return DTLS1_HM_FRAGMENT_RETRY;
 520 err:
 521     *ok = 0;
 522     return -1;
 523     }
 524
 525
 526 static long
 527 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
 528         {
 529         unsigned char *p;
 530         unsigned long l, frag_off, frag_len;
 531         int i,al;
 532         struct hm_header_st msg_hdr;
 533     unsigned long overlap;
 534
 535     /* see if we have the required fragment already */
 536     if (dtls1_retrieve_buffered_fragment(s, &l))
 537     {
 538         /* compute MAC, remove fragment headers */
 539         dtls1_process_handshake_fragment(s, l);
 540         s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 541         s->state = stn;
 542         return 1;
 543     }
 544
 545     /* get a handshake fragment from the record layer */
 546         p = (unsigned char *)s->init_buf->data;
 547
 548     /* read handshake message header */
 549         i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,&p[s->init_num],
 550                 DTLS1_HM_HEADER_LENGTH, 0);
 551         if (i <= 0)     /* nbio, or an error */
 552                 {
 553                 s->rwstate=SSL_READING;
 554                 *ok = 0;
 555                 return i;
 556                 }
 557
 558         OPENSSL_assert(i == DTLS1_HM_HEADER_LENGTH);
 559
 560         p += s->init_num;
 561     /* parse the message fragment header */
 562
 563     dtls1_get_message_header(p, &msg_hdr);
 564
 565     /*
 566      * if this is a future (or stale) message it gets buffered
 567      * (or dropped)--no further processing at this time
 568      */
 569     if ( msg_hdr.seq != s->d1->handshake_read_seq)
 570         return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
 571
 572     l = msg_hdr.msg_len;
 573     frag_off = msg_hdr.frag_off;
 574         frag_len = msg_hdr.frag_len;
 575
 576     /* sanity checking */
 577     if ( frag_off + frag_len > l)
 578         {
 579         al=SSL_AD_ILLEGAL_PARAMETER;
 580         SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 581         goto f_err;
 582         }
 583
 584         if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
 585         p[0] == SSL3_MT_HELLO_REQUEST)
 586         {
 587         /* The server may always send 'Hello Request' messages --
 588          * we are doing a handshake anyway now, so ignore them
 589          * if their format is correct. Does not count for
 590          * 'Finished' MAC. */
 591         if (p[1] == 0 && p[2] == 0 &&p[3] == 0)
 592             {
 593             if (s->msg_callback)
 594                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 595                     p, DTLS1_HM_HEADER_LENGTH, s,
 596                     s->msg_callback_arg);
 597
 598             s->init_num = 0;
 599             return dtls1_get_message_fragment(s, st1, stn,
 600                 max, ok);
 601             }
 602         else /* Incorrectly formated Hello request */
 603             {
 604             al=SSL_AD_UNEXPECTED_MESSAGE;
 605             SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 606             goto f_err;
 607             }
 608         }
 609
 610     /* XDTLS: do a sanity check on the fragment */
 611
 612     s->init_num += i;
 613
 614         if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */
 615                 {
 616                 /* BUF_MEM_grow takes an 'int' parameter */
 617                 if (l > (INT_MAX-DTLS1_HM_HEADER_LENGTH))
 618                         {
 619                         al=SSL_AD_ILLEGAL_PARAMETER;
 620                         SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 621                         goto f_err;
 622                         }
 623                 if (l && !BUF_MEM_grow_clean(s->init_buf,(int)l
 624                         + DTLS1_HM_HEADER_LENGTH))
 625                         {
 626                         SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,ERR_R_BUF_LIB);
 627                         goto err;
 628                         }
 629         /* Only do this test when we're reading the expected message.
 630          * Stale messages will be dropped and future messages will be buffered */
 631         if ( l > (unsigned long)max)
 632                         {
 633                         al=SSL_AD_ILLEGAL_PARAMETER;
 634                         SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 635                         goto f_err;
 636                         }
 637
 638                 s->s3->tmp.message_size=l;
 639                 }
 640
 641     if ( frag_len > (unsigned long)max)
 642         {
 643         al=SSL_AD_ILLEGAL_PARAMETER;
 644         SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 645         goto f_err;
 646         }
 647     if ( frag_len + s->init_num > (INT_MAX - DTLS1_HM_HEADER_LENGTH))
 648         {
 649         al=SSL_AD_ILLEGAL_PARAMETER;
 650         SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 651         goto f_err;
 652         }
 653
 654     if ( frag_len & !BUF_MEM_grow_clean(s->init_buf, (int)frag_len
 655              + DTLS1_HM_HEADER_LENGTH + s->init_num))
 656         {
 657         SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,ERR_R_BUF_LIB);
 658         goto err;
 659         }
 660
 661         if ( s->d1->r_msg_hdr.frag_off == 0)
 662                 {
 663                 s->s3->tmp.message_type = msg_hdr.type;
 664                 s->d1->r_msg_hdr.type = msg_hdr.type;
 665                 s->d1->r_msg_hdr.msg_len = l;
 666                 /* s->d1->r_msg_hdr.seq = seq_num; */
 667                 }
 668
 669         /* XDTLS:  ressurect this when restart is in place */
 670         s->state=stn;
 671
 672         /* next state (stn) */
 673         p = (unsigned char *)s->init_buf->data;
 674
 675         if ( frag_len > 0)
 676                 {
 677                 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 678             &p[s->init_num],
 679             frag_len,0);
 680         /* XDTLS:  fix this--message fragments cannot span multiple packets */
 681                 if (i <= 0)
 682                         {
 683                         s->rwstate=SSL_READING;
 684                         *ok = 0;
 685                         return i;
 686                         }
 687                 }
 688         else
 689                 i = 0;
 690
 691     /* XDTLS:  an incorrectly formatted fragment should cause the
 692      * handshake to fail */
 693         OPENSSL_assert(i == (int)frag_len);
 694
 695 #if 0
 696     /* Successfully read a fragment.
 697      * It may be (1) out of order, or
 698      *           (2) it's a repeat, in which case we dump it
 699      *           (3) the one we are expecting next (maybe with overlap)
 700      * If it is next one, it may overlap with previously read bytes
 701      */
 702
 703     /* case (1): buffer the future fragment
 704      * (we can treat fragments from a future message the same
 705      * as future fragments from the message being currently read, since
 706      * they are sematically simply out of order.
 707      */
 708     if ( msg_hdr.seq > s->d1->handshake_read_seq ||
 709         frag_off > s->init_num - DTLS1_HM_HEADER_LENGTH)
 710     {
 711         dtls1_buffer_handshake_fragment(s, &msg_hdr);
 712         return DTLS1_HM_FRAGMENT_RETRY;
 713     }
 714
 715     /* case (2):  drop the entire fragment, and try again */
 716     if ( msg_hdr.seq < s->d1->handshake_read_seq ||
 717         frag_off + frag_len < s->init_num - DTLS1_HM_HEADER_LENGTH)
 718         {
 719         s->init_num -= DTLS1_HM_HEADER_LENGTH;
 720         return DTLS1_HM_FRAGMENT_RETRY;
 721         }
 722 #endif
 723
 724     /* case (3): received a immediately useful fragment.  Determine the
 725      * possible overlap and copy the fragment.
 726      */
 727     overlap = (s->init_num - DTLS1_HM_HEADER_LENGTH) - frag_off;
 728
 729     /* retain the header for the first fragment */
 730     if ( s->init_num > DTLS1_HM_HEADER_LENGTH)
 731         {
 732         memmove(&(s->init_buf->data[s->init_num]),
 733             &(s->init_buf->data[s->init_num + DTLS1_HM_HEADER_LENGTH + overlap]),
 734             frag_len - overlap);
 735
 736         s->init_num += frag_len - overlap;
 737         }
 738     else
 739         s->init_num += frag_len;
 740
 741     dtls1_process_handshake_fragment(s, frag_len - overlap);
 742
 743         if (s->msg_callback)
 744                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, s->init_buf->data,
 745                         (size_t)s->init_num, s,
 746                         s->msg_callback_arg);
 747         *ok=1;
 748
 749         return s->init_num;
 750
 751 f_err:
 752         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 753     s->init_num = 0;
 754 err:
 755         *ok=0;
 756         return(-1);
 757         }
 758
 759 int dtls1_send_finished(SSL *s, int a, int b, const char *sender, int slen)
 760         {
 761         unsigned char *p,*d;
 762         int i;
 763         unsigned long l;
 764
 765         if (s->state == a)
 766                 {
 767                 d=(unsigned char *)s->init_buf->data;
 768                 p= &(d[DTLS1_HM_HEADER_LENGTH]);
 769
 770                 i=s->method->ssl3_enc->final_finish_mac(s,
 771                         &(s->s3->finish_dgst1),
 772                         &(s->s3->finish_dgst2),
 773                         sender,slen,s->s3->tmp.finish_md);
 774                 s->s3->tmp.finish_md_len = i;
 775                 memcpy(p, s->s3->tmp.finish_md, i);
 776                 p+=i;
 777                 l=i;
 778
 779 #ifdef OPENSSL_SYS_WIN16
 780                 /* MSVC 1.5 does not clear the top bytes of the word unless
 781                  * I do this.
 782                  */
 783                 l&=0xffff;
 784 #endif
 785
 786                 d = dtls1_set_message_header(s, d, SSL3_MT_FINISHED, l, 0, l);
 787                 s->init_num=(int)l+DTLS1_HM_HEADER_LENGTH;
 788                 s->init_off=0;
 789
 790                 /* buffer the message to handle re-xmits */
 791                 dtls1_buffer_message(s, 0);
 792
 793                 s->state=b;
 794                 }
 795
 796         /* SSL3_ST_SEND_xxxxxx_HELLO_B */
 797         return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
 798         }
 799
 800 /* for these 2 messages, we need to
 801  * ssl->enc_read_ctx                    re-init
 802  * ssl->s3->read_sequence               zero
 803  * ssl->s3->read_mac_secret             re-init
 804  * ssl->session->read_sym_enc           assign
 805  * ssl->session->read_compression       assign
 806  * ssl->session->read_hash              assign
 807  */
 808 int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
 809         {
 810         unsigned char *p;
 811
 812         if (s->state == a)
 813                 {
 814                 p=(unsigned char *)s->init_buf->data;
 815                 *p++=SSL3_MT_CCS;
 816                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
 817                 s->d1->next_handshake_write_seq++;
 818                 s2n(s->d1->handshake_write_seq,p);
 819
 820                 s->init_num=DTLS1_CCS_HEADER_LENGTH;
 821                 s->init_off=0;
 822
 823                 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
 824                         s->d1->handshake_write_seq, 0, 0);
 825
 826                 /* buffer the message to handle re-xmits */
 827                 dtls1_buffer_message(s, 1);
 828
 829                 s->state=b;
 830                 }
 831
 832         /* SSL3_ST_CW_CHANGE_B */
 833         return(dtls1_do_write(s,SSL3_RT_CHANGE_CIPHER_SPEC));
 834         }
 835
 836 unsigned long dtls1_output_cert_chain(SSL *s, X509 *x)
 837         {
 838         unsigned char *p;
 839         int n,i;
 840         unsigned long l= 3 + DTLS1_HM_HEADER_LENGTH;
 841         BUF_MEM *buf;
 842         X509_STORE_CTX xs_ctx;
 843         X509_OBJECT obj;
 844
 845         /* TLSv1 sends a chain with nothing in it, instead of an alert */
 846         buf=s->init_buf;
 847         if (!BUF_MEM_grow_clean(buf,10))
 848                 {
 849                 SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
 850                 return(0);
 851                 }
 852         if (x != NULL)
 853                 {
 854                 if(!X509_STORE_CTX_init(&xs_ctx,s->ctx->cert_store,NULL,NULL))
 855                         {
 856                         SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_X509_LIB);
 857                         return(0);
 858                         }
 859
 860                 for (;;)
 861                         {
 862                         n=i2d_X509(x,NULL);
 863                         if (!BUF_MEM_grow_clean(buf,(int)(n+l+3)))
 864                                 {
 865                                 SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
 866                                 return(0);
 867                                 }
 868                         p=(unsigned char *)&(buf->data[l]);
 869                         l2n3(n,p);
 870                         i2d_X509(x,&p);
 871                         l+=n+3;
 872                         if (X509_NAME_cmp(X509_get_subject_name(x),
 873                                 X509_get_issuer_name(x)) == 0) break;
 874
 875                         i=X509_STORE_get_by_subject(&xs_ctx,X509_LU_X509,
 876                                 X509_get_issuer_name(x),&obj);
 877                         if (i <= 0) break;
 878                         x=obj.data.x509;
 879                         /* Count is one too high since the X509_STORE_get uped the
 880                          * ref count */
 881                         X509_free(x);
 882                         }
 883
 884                 X509_STORE_CTX_cleanup(&xs_ctx);
 885                 }
 886
 887         /* Thawte special :-) */
 888         if (s->ctx->extra_certs != NULL)
 889         for (i=0; i<sk_X509_num(s->ctx->extra_certs); i++)
 890                 {
 891                 x=sk_X509_value(s->ctx->extra_certs,i);
 892                 n=i2d_X509(x,NULL);
 893                 if (!BUF_MEM_grow_clean(buf,(int)(n+l+3)))
 894                         {
 895                         SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
 896                         return(0);
 897                         }
 898                 p=(unsigned char *)&(buf->data[l]);
 899                 l2n3(n,p);
 900                 i2d_X509(x,&p);
 901                 l+=n+3;
 902                 }
 903
 904         l-= (3 + DTLS1_HM_HEADER_LENGTH);
 905
 906         p=(unsigned char *)&(buf->data[DTLS1_HM_HEADER_LENGTH]);
 907         l2n3(l,p);
 908         l+=3;
 909         p=(unsigned char *)&(buf->data[0]);
 910         p = dtls1_set_message_header(s, p, SSL3_MT_CERTIFICATE, l, 0, l);
 911
 912         l+=DTLS1_HM_HEADER_LENGTH;
 913         return(l);
 914         }
 915
 916 int dtls1_read_failed(SSL *s, int code)
 917     {
 918     DTLS1_STATE *state;
 919     BIO *bio;
 920     int send_alert = 0;
 921
 922     if ( code > 0)
 923         {
 924         fprintf( stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
 925         return 1;
 926         }
 927
 928     bio = SSL_get_rbio(s);
 929     if ( ! BIO_dgram_recv_timedout(bio))
 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     state = s->d1;
 943     state->timeout.num_alerts++;
 944     if ( state->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT)
 945         {
 946         /* fail the connection, enough alerts have been sent */
 947         SSLerr(SSL_F_DTLS1_READ_FAILED,SSL_R_READ_TIMEOUT_EXPIRED);
 948         return 0;
 949         }
 950
 951     state->timeout.read_timeouts++;
 952     if ( state->timeout.read_timeouts > DTLS1_TMO_READ_COUNT)
 953         {
 954         send_alert = 1;
 955         state->timeout.read_timeouts = 1;
 956         }
 957
 958
 959 #if 0 /* for now, each alert contains only one record number */
 960     item = pqueue_peek(state->rcvd_records);
 961     if ( item )
 962         {
 963         /* send an alert immediately for all the missing records */
 964         }
 965     else
 966 #endif
 967
 968 #if 0  /* no more alert sending, just retransmit the last set of messages */
 969         if ( send_alert)
 970             ssl3_send_alert(s,SSL3_AL_WARNING,
 971                 DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
 972 #endif
 973
 974     return dtls1_retransmit_buffered_messages(s) ;
 975     }
 976
 977
 978 static int
 979 dtls1_retransmit_buffered_messages(SSL *s)
 980     {
 981     pqueue sent = s->d1->sent_messages;
 982     piterator iter;
 983     pitem *item;
 984     hm_fragment *frag;
 985     int found = 0;
 986
 987     iter = pqueue_iterator(sent);
 988
 989     for ( item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter))
 990         {
 991         frag = (hm_fragment *)item->data;
 992         if ( dtls1_retransmit_message(s, frag->msg_header.seq, 0, &found) <= 0 &&
 993             found)
 994             {
 995             fprintf(stderr, "dtls1_retransmit_message() failed\n");
 996             return -1;
 997             }
 998         }
 999
1000     return 1;
1001     }
1002
1003 #if 0
1004 static dtls1_message_buffer *
1005 dtls1_message_buffer_new(unsigned int len)
1006     {
1007     dtls1_message_buffer *msg_buf;
1008
1009     msg_buf = (dtls1_message_buffer *)
1010         OPENSSL_malloc(sizeof(dtls1_message_buffer));
1011     if ( msg_buf == NULL)
1012         return NULL;
1013
1014     memset(msg_buf, 0x00, sizeof(dtls1_message_buffer));
1015
1016     msg_buf->data = (unsigned char *) OPENSSL_malloc(len);
1017     if ( msg_buf->data == NULL)
1018         {
1019         OPENSSL_free(msg_buf);
1020         return NULL;
1021         }
1022
1023     memset(msg_buf->data, 0x00, len);
1024     return msg_buf;
1025     }
1026 #endif
1027
1028 #if 0
1029 static void
1030 dtls1_message_buffer_free(dtls1_message_buffer *msg_buf)
1031     {
1032     if (msg_buf != NULL)
1033         {
1034         OPENSSL_free(msg_buf->data);
1035         OPENSSL_free(msg_buf);
1036         }
1037     }
1038 #endif
1039
1040 int
1041 dtls1_buffer_message(SSL *s, int is_ccs)
1042     {
1043     pitem *item;
1044     hm_fragment *frag;
1045     unsigned char seq64be[8];
1046
1047     /* this function is called immediately after a message has
1048      * been serialized */
1049     OPENSSL_assert(s->init_off == 0);
1050
1051     frag = dtls1_hm_fragment_new(s->init_num);
1052
1053     memcpy(frag->fragment, s->init_buf->data, s->init_num);
1054
1055     if ( is_ccs)
1056         {
1057         OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1058             DTLS1_CCS_HEADER_LENGTH == (unsigned int)s->init_num);
1059         }
1060     else
1061         {
1062         OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1063             DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
1064         }
1065
1066     frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1067     frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1068     frag->msg_header.type = s->d1->w_msg_hdr.type;
1069     frag->msg_header.frag_off = 0;
1070     frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1071     frag->msg_header.is_ccs = is_ccs;
1072
1073     memset(seq64be,0,sizeof(seq64be));
1074     seq64be[6] = (unsigned char)(frag->msg_header.seq>>8);
1075     seq64be[7] = (unsigned char)(frag->msg_header.seq);
1076
1077     item = pitem_new(seq64be, frag);
1078     if ( item == NULL)
1079         {
1080         dtls1_hm_fragment_free(frag);
1081         return 0;
1082         }
1083
1084 #if 0
1085     fprintf( stderr, "buffered messge: \ttype = %xx\n", msg_buf->type);
1086     fprintf( stderr, "\t\t\t\t\tlen = %d\n", msg_buf->len);
1087     fprintf( stderr, "\t\t\t\t\tseq_num = %d\n", msg_buf->seq_num);
1088 #endif
1089
1090     pqueue_insert(s->d1->sent_messages, item);
1091     return 1;
1092     }
1093
1094 int
1095 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
1096     int *found)
1097     {
1098     int ret;
1099     /* XDTLS: for now assuming that read/writes are blocking */
1100     pitem *item;
1101     hm_fragment *frag ;
1102     unsigned long header_length;
1103     unsigned char seq64be[8];
1104
1105     /*
1106       OPENSSL_assert(s->init_num == 0);
1107       OPENSSL_assert(s->init_off == 0);
1108      */
1109
1110     /* XDTLS:  the requested message ought to be found, otherwise error */
1111     memset(seq64be,0,sizeof(seq64be));
1112     seq64be[6] = (unsigned char)(seq>>8);
1113     seq64be[7] = (unsigned char)seq;
1114
1115     item = pqueue_find(s->d1->sent_messages, seq64be);
1116     if ( item == NULL)
1117         {
1118         fprintf(stderr, "retransmit:  message %d non-existant\n", seq);
1119         *found = 0;
1120         return 0;
1121         }
1122
1123     *found = 1;
1124     frag = (hm_fragment *)item->data;
1125
1126     if ( frag->msg_header.is_ccs)
1127         header_length = DTLS1_CCS_HEADER_LENGTH;
1128     else
1129         header_length = DTLS1_HM_HEADER_LENGTH;
1130
1131     memcpy(s->init_buf->data, frag->fragment,
1132         frag->msg_header.msg_len + header_length);
1133         s->init_num = frag->msg_header.msg_len + header_length;
1134
1135     dtls1_set_message_header_int(s, frag->msg_header.type,
1136         frag->msg_header.msg_len, frag->msg_header.seq, 0,
1137         frag->msg_header.frag_len);
1138
1139     s->d1->retransmitting = 1;
1140     ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1141         SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1142     s->d1->retransmitting = 0;
1143
1144     BIO_flush(SSL_get_wbio(s));
1145     return ret;
1146     }
1147
1148 /* call this function when the buffered messages are no longer needed */
1149 void
1150 dtls1_clear_record_buffer(SSL *s)
1151     {
1152     pitem *item;
1153
1154     for(item = pqueue_pop(s->d1->sent_messages);
1155         item != NULL; item = pqueue_pop(s->d1->sent_messages))
1156         {
1157         dtls1_hm_fragment_free((hm_fragment *)item->data);
1158         pitem_free(item);
1159         }
1160     }
1161
1162
1163 unsigned char *
1164 dtls1_set_message_header(SSL *s, unsigned char *p, unsigned char mt,
1165     unsigned long len, unsigned long frag_off, unsigned long frag_len)
1166     {
1167     if ( frag_off == 0)
1168         {
1169         s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1170         s->d1->next_handshake_write_seq++;
1171         }
1172
1173     dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1174         frag_off, frag_len);
1175
1176     return p += DTLS1_HM_HEADER_LENGTH;
1177     }
1178
1179
1180 /* don't actually do the writing, wait till the MTU has been retrieved */
1181 static void
1182 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1183     unsigned long len, unsigned short seq_num, unsigned long frag_off,
1184     unsigned long frag_len)
1185     {
1186     struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1187
1188     msg_hdr->type = mt;
1189     msg_hdr->msg_len = len;
1190     msg_hdr->seq = seq_num;
1191     msg_hdr->frag_off = frag_off;
1192     msg_hdr->frag_len = frag_len;
1193 }
1194
1195 static void
1196 dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1197         unsigned long frag_len)
1198     {
1199     struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1200
1201     msg_hdr->frag_off = frag_off;
1202     msg_hdr->frag_len = frag_len;
1203     }
1204
1205 static unsigned char *
1206 dtls1_write_message_header(SSL *s, unsigned char *p)
1207     {
1208     struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1209
1210     *p++ = msg_hdr->type;
1211     l2n3(msg_hdr->msg_len, p);
1212
1213     s2n(msg_hdr->seq, p);
1214     l2n3(msg_hdr->frag_off, p);
1215     l2n3(msg_hdr->frag_len, p);
1216
1217     return p;
1218     }
1219
1220 static unsigned int
1221 dtls1_min_mtu(void)
1222     {
1223     return
1224         g_probable_mtu[(sizeof(g_probable_mtu) /
1225            sizeof(g_probable_mtu[0])) - 1];
1226     }
1227
1228 static unsigned int
1229 dtls1_guess_mtu(unsigned int curr_mtu)
1230         {
1231         int i;
1232
1233         if ( curr_mtu == 0 )
1234                 return g_probable_mtu[0] ;
1235
1236         for ( i = 0; i < sizeof(g_probable_mtu)/sizeof(g_probable_mtu[0]); i++)
1237                 if ( curr_mtu > g_probable_mtu[i])
1238                         return g_probable_mtu[i];
1239
1240         return curr_mtu;
1241         }
1242
1243 void
1244 dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1245     {
1246     memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
1247     msg_hdr->type = *(data++);
1248     n2l3(data, msg_hdr->msg_len);
1249
1250     n2s(data, msg_hdr->seq);
1251     n2l3(data, msg_hdr->frag_off);
1252     n2l3(data, msg_hdr->frag_len);
1253     }
1254
1255 void
1256 dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
1257     {
1258     memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
1259
1260     ccs_hdr->type = *(data++);
1261     n2s(data, ccs_hdr->seq);
1262 }