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                         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, &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 == 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,
 328         int     *ok)
 329         {
 330         int i, al;
 331
 332         /* s3->tmp is used to store messages that are unexpected, caused
 333          * by the absence of an optional handshake message */
 334         if (s->s3->tmp.reuse_message)
 335                 {
 336                 s->s3->tmp.reuse_message=0;
 337                 if ((mt >= 0) && (s->s3->tmp.message_type != mt))
 338                         {
 339                         al=SSL_AD_UNEXPECTED_MESSAGE;
 340                         SSLerr(SSL_F_SSL3_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
 341                         goto f_err;
 342                         }
 343                 *ok=1;
 344                 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 345                 s->init_num = (int)s->s3->tmp.message_size;
 346                 return s->init_num;
 347                 }
 348
 349         do
 350                 {
 351                 if ( s->d1->r_msg_hdr.frag_off == 0)
 352                         {
 353                         /* s->d1->r_message_header.msg_len = 0; */
 354                         memset(&(s->d1->r_msg_hdr), 0x00, sizeof(struct hm_header_st));
 355                         }
 356
 357                 i = dtls1_get_message_fragment(s, st1, stn, max, ok);
 358                 if ( i == DTLS1_HM_BAD_FRAGMENT ||
 359             i == DTLS1_HM_FRAGMENT_RETRY)  /* bad fragment received */
 360                         continue;
 361                 else if ( i <= 0 && !*ok)
 362                         return i;
 363
 364                 if (s->d1->r_msg_hdr.msg_len == s->init_num - DTLS1_HM_HEADER_LENGTH)
 365                         {
 366                         memset(&(s->d1->r_msg_hdr), 0x00, sizeof(struct hm_header_st));
 367
 368                         s->d1->handshake_read_seq++;
 369                         /* we just read a handshake message from the other side:
 370                          * this means that we don't need to retransmit of the
 371                          * buffered messages.
 372                          * XDTLS: may be able clear out this
 373                          * buffer a little sooner (i.e if an out-of-order
 374                          * handshake message/record is received at the record
 375                          * layer.
 376                          * XDTLS: exception is that the server needs to
 377                          * know that change cipher spec and finished messages
 378                          * have been received by the client before clearing this
 379                          * buffer.  this can simply be done by waiting for the
 380                          * first data  segment, but is there a better way?  */
 381                         dtls1_clear_record_buffer(s);
 382
 383             s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 384                         return s->init_num - DTLS1_HM_HEADER_LENGTH;
 385                         }
 386                 else
 387                         s->d1->r_msg_hdr.frag_off = i;
 388                 } while(1) ;
 389
 390 f_err:
 391         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 392         *ok = 0;
 393         return -1;
 394         }
 395
 396
 397 static int
 398 dtls1_retrieve_buffered_fragment(SSL *s, unsigned long *copied)
 399     {
 400     /* (0) check whether the desired fragment is available
 401      * if so:
 402      * (1) copy over the fragment to s->init_buf->data[]
 403      * (2) update s->init_num
 404      */
 405     pitem *item;
 406     hm_fragment *frag;
 407     unsigned long overlap;
 408     unsigned char *p;
 409
 410     item = pqueue_peek(s->d1->buffered_messages);
 411     if ( item == NULL)
 412         return 0;
 413
 414     frag = (hm_fragment *)item->data;
 415
 416     if ( s->d1->handshake_read_seq == frag->msg_header.seq &&
 417         frag->msg_header.frag_off <= s->init_num - DTLS1_HM_HEADER_LENGTH)
 418         {
 419         pqueue_pop(s->d1->buffered_messages);
 420         overlap = s->init_num - DTLS1_HM_HEADER_LENGTH
 421             - frag->msg_header.frag_off;
 422
 423         p = frag->fragment;
 424
 425         memcpy(&s->init_buf->data[s->init_num],
 426             p + DTLS1_HM_HEADER_LENGTH + overlap,
 427             frag->msg_header.frag_len - overlap);
 428
 429         OPENSSL_free(frag->fragment);
 430         OPENSSL_free(frag);
 431         pitem_free(item);
 432
 433         *copied = frag->msg_header.frag_len - overlap;
 434         return *copied;
 435         }
 436     else
 437         return 0;
 438     }
 439
 440
 441 static int
 442 dtls1_buffer_handshake_fragment(SSL *s, struct hm_header_st* msg_hdr)
 443 {
 444     hm_fragment *frag = NULL;
 445     pitem *item = NULL;
 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     item = pitem_new(msg_hdr->seq, frag);
 457     if ( item == NULL)
 458         goto err;
 459
 460     pqueue_insert(s->d1->buffered_messages, item);
 461     return 1;
 462
 463 err:
 464     if ( frag != NULL) dtls1_hm_fragment_free(frag);
 465     if ( item != NULL) OPENSSL_free(item);
 466     return 0;
 467 }
 468
 469
 470 static void
 471 dtls1_process_handshake_fragment(SSL *s, int frag_len)
 472     {
 473     unsigned char *p;
 474
 475     p = s->init_buf->data;
 476
 477         ssl3_finish_mac(s, &p[s->init_num - frag_len], frag_len);
 478     }
 479
 480
 481 static int
 482 dtls1_process_out_of_seq_message(SSL *s, struct hm_header_st *msg_hdr, int *ok)
 483     {
 484     int i;
 485     unsigned char *p;
 486
 487     /* make sure there's enough room to read this fragment */
 488     if ( (int)msg_hdr->frag_len && !BUF_MEM_grow_clean(s->init_buf,
 489              (int)msg_hdr->frag_len + DTLS1_HM_HEADER_LENGTH + s->init_num))
 490         {
 491         SSLerr(SSL_F_SSL3_GET_MESSAGE,ERR_R_BUF_LIB);
 492         goto err;
 493         }
 494
 495     p = s->init_buf->data;
 496
 497     /* read the body of the fragment (header has already been read */
 498     if ( msg_hdr->frag_len > 0)
 499                 {
 500                 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 501             &p[s->init_num],
 502             msg_hdr->frag_len,0);
 503                 if (i <= 0)
 504                         {
 505                         *ok = 0;
 506                         return i;
 507                         }
 508                 }
 509
 510     if ( msg_hdr->seq > s->d1->handshake_read_seq)
 511         dtls1_buffer_handshake_fragment(s, msg_hdr);
 512     else
 513         OPENSSL_assert(msg_hdr->seq < s->d1->handshake_read_seq);
 514
 515     return DTLS1_HM_FRAGMENT_RETRY;
 516 err:
 517     *ok = 0;
 518     return -1;
 519     }
 520
 521
 522 static long
 523 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
 524         {
 525         unsigned char *p;
 526         unsigned long l, frag_off, frag_len;
 527         int i,al;
 528         struct hm_header_st msg_hdr;
 529     unsigned long overlap;
 530
 531     /* see if we have the required fragment already */
 532     if (dtls1_retrieve_buffered_fragment(s, &l))
 533     {
 534         /* compute MAC, remove fragment headers */
 535         dtls1_process_handshake_fragment(s, l);
 536         s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 537         s->state = stn;
 538         return 1;
 539     }
 540
 541     /* get a handshake fragment from the record layer */
 542         p = (unsigned char *)s->init_buf->data;
 543
 544     /* read handshake message header */
 545         i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,&p[s->init_num],
 546                 DTLS1_HM_HEADER_LENGTH, 0);
 547         if (i <= 0)     /* nbio, or an error */
 548                 {
 549                 s->rwstate=SSL_READING;
 550                 *ok = 0;
 551                 return i;
 552                 }
 553
 554         OPENSSL_assert(i == DTLS1_HM_HEADER_LENGTH);
 555
 556         p += s->init_num;
 557     /* parse the message fragment header */
 558
 559     dtls1_get_message_header(p, &msg_hdr);
 560
 561     /*
 562      * if this is a future (or stale) message it gets buffered
 563      * (or dropped)--no further processing at this time
 564      */
 565     if ( msg_hdr.seq != s->d1->handshake_read_seq)
 566         return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
 567
 568     l = msg_hdr.msg_len;
 569     frag_off = msg_hdr.frag_off;
 570         frag_len = msg_hdr.frag_len;
 571
 572     /* sanity checking */
 573     if ( frag_off + frag_len > l)
 574         {
 575         al=SSL_AD_ILLEGAL_PARAMETER;
 576         SSLerr(SSL_F_SSL3_GET_MESSAGE,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 577         goto f_err;
 578         }
 579
 580         if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
 581         p[0] == SSL3_MT_HELLO_REQUEST)
 582         {
 583         /* The server may always send 'Hello Request' messages --
 584          * we are doing a handshake anyway now, so ignore them
 585          * if their format is correct. Does not count for
 586          * 'Finished' MAC. */
 587         if (p[1] == 0 && p[2] == 0 &&p[3] == 0)
 588             {
 589             if (s->msg_callback)
 590                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 591                     p, DTLS1_HM_HEADER_LENGTH, s,
 592                     s->msg_callback_arg);
 593
 594             s->init_num = 0;
 595             return dtls1_get_message_fragment(s, st1, stn,
 596                 max, ok);
 597             }
 598         else /* Incorrectly formated Hello request */
 599             {
 600             al=SSL_AD_UNEXPECTED_MESSAGE;
 601             SSLerr(SSL_F_SSL3_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
 602             goto f_err;
 603             }
 604         }
 605
 606     /* XDTLS: do a sanity check on the fragment */
 607
 608     s->init_num += i;
 609
 610         if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */
 611                 {
 612                 /* BUF_MEM_grow takes an 'int' parameter */
 613                 if (l > (INT_MAX-DTLS1_HM_HEADER_LENGTH))
 614                         {
 615                         al=SSL_AD_ILLEGAL_PARAMETER;
 616                         SSLerr(SSL_F_SSL3_GET_MESSAGE,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 617                         goto f_err;
 618                         }
 619                 if (l && !BUF_MEM_grow_clean(s->init_buf,(int)l
 620                         + DTLS1_HM_HEADER_LENGTH))
 621                         {
 622                         SSLerr(SSL_F_SSL3_GET_MESSAGE,ERR_R_BUF_LIB);
 623                         goto err;
 624                         }
 625         /* Only do this test when we're reading the expected message.
 626          * Stale messages will be dropped and future messages will be buffered */
 627         if ( l > (unsigned long)max)
 628                         {
 629                         al=SSL_AD_ILLEGAL_PARAMETER;
 630                         SSLerr(SSL_F_SSL3_GET_MESSAGE,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 631                         goto f_err;
 632                         }
 633
 634                 s->s3->tmp.message_size=l;
 635                 }
 636
 637     if ( frag_len > (unsigned long)max)
 638         {
 639         al=SSL_AD_ILLEGAL_PARAMETER;
 640         SSLerr(SSL_F_SSL3_GET_MESSAGE,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 641         goto f_err;
 642         }
 643     if ( frag_len + s->init_num > (INT_MAX - DTLS1_HM_HEADER_LENGTH))
 644         {
 645         al=SSL_AD_ILLEGAL_PARAMETER;
 646         SSLerr(SSL_F_SSL3_GET_MESSAGE,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 647         goto f_err;
 648         }
 649
 650     if ( frag_len & !BUF_MEM_grow_clean(s->init_buf, (int)frag_len
 651              + DTLS1_HM_HEADER_LENGTH + s->init_num))
 652         {
 653         SSLerr(SSL_F_SSL3_GET_MESSAGE,ERR_R_BUF_LIB);
 654         goto err;
 655         }
 656
 657         if ( s->d1->r_msg_hdr.frag_off == 0)
 658                 {
 659                 s->s3->tmp.message_type = msg_hdr.type;
 660                 s->d1->r_msg_hdr.type = msg_hdr.type;
 661                 s->d1->r_msg_hdr.msg_len = l;
 662                 /* s->d1->r_msg_hdr.seq = seq_num; */
 663                 }
 664
 665         /* XDTLS:  ressurect this when restart is in place */
 666         s->state=stn;
 667
 668         /* next state (stn) */
 669         p = s->init_buf->data;
 670
 671         if ( frag_len > 0)
 672                 {
 673                 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 674             &p[s->init_num],
 675             frag_len,0);
 676         /* XDTLS:  fix this--message fragments cannot span multiple packets */
 677                 if (i <= 0)
 678                         {
 679                         s->rwstate=SSL_READING;
 680                         *ok = 0;
 681                         return i;
 682                         }
 683                 }
 684         else
 685                 i = 0;
 686
 687     /* XDTLS:  an incorrectly formatted fragment should cause the
 688      * handshake to fail */
 689         OPENSSL_assert(i == frag_len);
 690
 691 #if 0
 692     /* Successfully read a fragment.
 693      * It may be (1) out of order, or
 694      *           (2) it's a repeat, in which case we dump it
 695      *           (3) the one we are expecting next (maybe with overlap)
 696      * If it is next one, it may overlap with previously read bytes
 697      */
 698
 699     /* case (1): buffer the future fragment
 700      * (we can treat fragments from a future message the same
 701      * as future fragments from the message being currently read, since
 702      * they are sematically simply out of order.
 703      */
 704     if ( msg_hdr.seq > s->d1->handshake_read_seq ||
 705         frag_off > s->init_num - DTLS1_HM_HEADER_LENGTH)
 706     {
 707         dtls1_buffer_handshake_fragment(s, &msg_hdr);
 708         return DTLS1_HM_FRAGMENT_RETRY;
 709     }
 710
 711     /* case (2):  drop the entire fragment, and try again */
 712     if ( msg_hdr.seq < s->d1->handshake_read_seq ||
 713         frag_off + frag_len < s->init_num - DTLS1_HM_HEADER_LENGTH)
 714         {
 715         s->init_num -= DTLS1_HM_HEADER_LENGTH;
 716         return DTLS1_HM_FRAGMENT_RETRY;
 717         }
 718 #endif
 719
 720     /* case (3): received a immediately useful fragment.  Determine the
 721      * possible overlap and copy the fragment.
 722      */
 723     overlap = (s->init_num - DTLS1_HM_HEADER_LENGTH) - frag_off;
 724
 725     /* retain the header for the first fragment */
 726     if ( s->init_num > DTLS1_HM_HEADER_LENGTH)
 727         {
 728         memmove(&(s->init_buf->data[s->init_num]),
 729             &(s->init_buf->data[s->init_num + DTLS1_HM_HEADER_LENGTH + overlap]),
 730             frag_len - overlap);
 731
 732         s->init_num += frag_len - overlap;
 733         }
 734     else
 735         s->init_num += frag_len;
 736
 737     dtls1_process_handshake_fragment(s, frag_len - overlap);
 738
 739         if (s->msg_callback)
 740                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, s->init_buf->data,
 741                         (size_t)s->init_num, s,
 742                         s->msg_callback_arg);
 743         *ok=1;
 744
 745         return s->init_num;
 746
 747 f_err:
 748         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 749     s->init_num = 0;
 750 err:
 751         *ok=0;
 752         return(-1);
 753         }
 754
 755 int dtls1_send_finished(SSL *s, int a, int b, const char *sender, int slen)
 756         {
 757         unsigned char *p,*d;
 758         int i;
 759         unsigned long l;
 760
 761         if (s->state == a)
 762                 {
 763                 d=(unsigned char *)s->init_buf->data;
 764                 p= &(d[DTLS1_HM_HEADER_LENGTH]);
 765
 766                 i=s->method->ssl3_enc->final_finish_mac(s,
 767                         &(s->s3->finish_dgst1),
 768                         &(s->s3->finish_dgst2),
 769                         sender,slen,s->s3->tmp.finish_md);
 770                 s->s3->tmp.finish_md_len = i;
 771                 memcpy(p, s->s3->tmp.finish_md, i);
 772                 p+=i;
 773                 l=i;
 774
 775 #ifdef OPENSSL_SYS_WIN16
 776                 /* MSVC 1.5 does not clear the top bytes of the word unless
 777                  * I do this.
 778                  */
 779                 l&=0xffff;
 780 #endif
 781
 782                 d = dtls1_set_message_header(s, d, SSL3_MT_FINISHED, l, 0, l);
 783                 s->init_num=(int)l+DTLS1_HM_HEADER_LENGTH;
 784                 s->init_off=0;
 785
 786                 /* buffer the message to handle re-xmits */
 787                 dtls1_buffer_message(s, 0);
 788
 789                 s->state=b;
 790                 }
 791
 792         /* SSL3_ST_SEND_xxxxxx_HELLO_B */
 793         return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
 794         }
 795
 796 /* for these 2 messages, we need to
 797  * ssl->enc_read_ctx                    re-init
 798  * ssl->s3->read_sequence               zero
 799  * ssl->s3->read_mac_secret             re-init
 800  * ssl->session->read_sym_enc           assign
 801  * ssl->session->read_compression       assign
 802  * ssl->session->read_hash              assign
 803  */
 804 int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
 805         {
 806         unsigned char *p;
 807
 808         if (s->state == a)
 809                 {
 810                 p=(unsigned char *)s->init_buf->data;
 811                 *p++=SSL3_MT_CCS;
 812                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
 813                 s->d1->next_handshake_write_seq++;
 814                 s2n(s->d1->handshake_write_seq,p);
 815
 816                 s->init_num=DTLS1_CCS_HEADER_LENGTH;
 817                 s->init_off=0;
 818
 819                 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
 820                         s->d1->handshake_write_seq, 0, 0);
 821
 822                 /* buffer the message to handle re-xmits */
 823                 dtls1_buffer_message(s, 1);
 824
 825                 s->state=b;
 826                 }
 827
 828         /* SSL3_ST_CW_CHANGE_B */
 829         return(dtls1_do_write(s,SSL3_RT_CHANGE_CIPHER_SPEC));
 830         }
 831
 832 unsigned long dtls1_output_cert_chain(SSL *s, X509 *x)
 833         {
 834         unsigned char *p;
 835         int n,i;
 836         unsigned long l= 3 + DTLS1_HM_HEADER_LENGTH;
 837         BUF_MEM *buf;
 838         X509_STORE_CTX xs_ctx;
 839         X509_OBJECT obj;
 840
 841         /* TLSv1 sends a chain with nothing in it, instead of an alert */
 842         buf=s->init_buf;
 843         if (!BUF_MEM_grow_clean(buf,10))
 844                 {
 845                 SSLerr(SSL_F_SSL3_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
 846                 return(0);
 847                 }
 848         if (x != NULL)
 849                 {
 850                 if(!X509_STORE_CTX_init(&xs_ctx,s->ctx->cert_store,NULL,NULL))
 851                         {
 852                         SSLerr(SSL_F_SSL3_OUTPUT_CERT_CHAIN,ERR_R_X509_LIB);
 853                         return(0);
 854                         }
 855
 856                 for (;;)
 857                         {
 858                         n=i2d_X509(x,NULL);
 859                         if (!BUF_MEM_grow_clean(buf,(int)(n+l+3)))
 860                                 {
 861                                 SSLerr(SSL_F_SSL3_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
 862                                 return(0);
 863                                 }
 864                         p=(unsigned char *)&(buf->data[l]);
 865                         l2n3(n,p);
 866                         i2d_X509(x,&p);
 867                         l+=n+3;
 868                         if (X509_NAME_cmp(X509_get_subject_name(x),
 869                                 X509_get_issuer_name(x)) == 0) break;
 870
 871                         i=X509_STORE_get_by_subject(&xs_ctx,X509_LU_X509,
 872                                 X509_get_issuer_name(x),&obj);
 873                         if (i <= 0) break;
 874                         x=obj.data.x509;
 875                         /* Count is one too high since the X509_STORE_get uped the
 876                          * ref count */
 877                         X509_free(x);
 878                         }
 879
 880                 X509_STORE_CTX_cleanup(&xs_ctx);
 881                 }
 882
 883         /* Thawte special :-) */
 884         if (s->ctx->extra_certs != NULL)
 885         for (i=0; i<sk_X509_num(s->ctx->extra_certs); i++)
 886                 {
 887                 x=sk_X509_value(s->ctx->extra_certs,i);
 888                 n=i2d_X509(x,NULL);
 889                 if (!BUF_MEM_grow_clean(buf,(int)(n+l+3)))
 890                         {
 891                         SSLerr(SSL_F_SSL3_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
 892                         return(0);
 893                         }
 894                 p=(unsigned char *)&(buf->data[l]);
 895                 l2n3(n,p);
 896                 i2d_X509(x,&p);
 897                 l+=n+3;
 898                 }
 899
 900         l-= (3 + DTLS1_HM_HEADER_LENGTH);
 901
 902         p=(unsigned char *)&(buf->data[DTLS1_HM_HEADER_LENGTH]);
 903         l2n3(l,p);
 904         l+=3;
 905         p=(unsigned char *)&(buf->data[0]);
 906         p = dtls1_set_message_header(s, p, SSL3_MT_CERTIFICATE, l, 0, l);
 907
 908         l+=DTLS1_HM_HEADER_LENGTH;
 909         return(l);
 910         }
 911
 912 int dtls1_read_failed(SSL *s, int code)
 913     {
 914     DTLS1_STATE *state;
 915     BIO *bio;
 916     int send_alert = 0;
 917
 918     if ( code > 0)
 919         {
 920         fprintf( stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
 921         return 1;
 922         }
 923
 924     bio = SSL_get_rbio(s);
 925     if ( ! BIO_dgram_recv_timedout(bio))
 926         {
 927         /* not a timeout, none of our business,
 928            let higher layers handle this.  in fact it's probably an error */
 929         return code;
 930         }
 931
 932     if ( ! SSL_in_init(s))  /* done, no need to send a retransmit */
 933         {
 934         BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
 935         return code;
 936         }
 937
 938     state = s->d1;
 939     state->timeout.num_alerts++;
 940     if ( state->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT)
 941         {
 942         /* fail the connection, enough alerts have been sent */
 943         SSLerr(SSL_F_DTLS1_READ_FAILED,SSL_R_READ_TIMEOUT_EXPIRED);
 944         return 0;
 945         }
 946
 947     state->timeout.read_timeouts++;
 948     if ( state->timeout.read_timeouts > DTLS1_TMO_READ_COUNT)
 949         {
 950         send_alert = 1;
 951         state->timeout.read_timeouts = 1;
 952         }
 953
 954
 955 #if 0 /* for now, each alert contains only one record number */
 956     item = pqueue_peek(state->rcvd_records);
 957     if ( item )
 958         {
 959         /* send an alert immediately for all the missing records */
 960         }
 961     else
 962 #endif
 963
 964 #if 0  /* no more alert sending, just retransmit the last set of messages */
 965         if ( send_alert)
 966             ssl3_send_alert(s,SSL3_AL_WARNING,
 967                 DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
 968 #endif
 969
 970     return dtls1_retransmit_buffered_messages(s) ;
 971     }
 972
 973
 974 static int
 975 dtls1_retransmit_buffered_messages(SSL *s)
 976     {
 977     pqueue sent = s->d1->sent_messages;
 978     piterator iter;
 979     pitem *item;
 980     hm_fragment *frag;
 981     int found = 0;
 982
 983     iter = pqueue_iterator(sent);
 984
 985     for ( item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter))
 986         {
 987         frag = (hm_fragment *)item->data;
 988         if ( dtls1_retransmit_message(s, frag->msg_header.seq, 0, &found) <= 0 &&
 989             found)
 990             {
 991             fprintf(stderr, "dtls1_retransmit_message() failed\n");
 992             return -1;
 993             }
 994         }
 995
 996     return 1;
 997     }
 998
 999 #if 0
1000 static dtls1_message_buffer *
1001 dtls1_message_buffer_new(unsigned int len)
1002     {
1003     dtls1_message_buffer *msg_buf;
1004
1005     msg_buf = (dtls1_message_buffer *)
1006         OPENSSL_malloc(sizeof(dtls1_message_buffer));
1007     if ( msg_buf == NULL)
1008         return NULL;
1009
1010     memset(msg_buf, 0x00, sizeof(dtls1_message_buffer));
1011
1012     msg_buf->data = (unsigned char *) OPENSSL_malloc(len);
1013     if ( msg_buf->data == NULL)
1014         {
1015         OPENSSL_free(msg_buf);
1016         return NULL;
1017         }
1018
1019     memset(msg_buf->data, 0x00, len);
1020     return msg_buf;
1021     }
1022 #endif
1023
1024 #if 0
1025 static void
1026 dtls1_message_buffer_free(dtls1_message_buffer *msg_buf)
1027     {
1028     if (msg_buf != NULL)
1029         {
1030         OPENSSL_free(msg_buf->data);
1031         OPENSSL_free(msg_buf);
1032         }
1033     }
1034 #endif
1035
1036 int
1037 dtls1_buffer_message(SSL *s, int is_ccs)
1038     {
1039     pitem *item;
1040     hm_fragment *frag;
1041
1042     /* this function is called immediately after a message has
1043      * been serialized */
1044     OPENSSL_assert(s->init_off == 0);
1045
1046     frag = dtls1_hm_fragment_new(s->init_num);
1047
1048     memcpy(frag->fragment, s->init_buf->data, s->init_num);
1049
1050     if ( is_ccs)
1051         {
1052         OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1053             DTLS1_CCS_HEADER_LENGTH == s->init_num);
1054         }
1055     else
1056         {
1057         OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1058             DTLS1_HM_HEADER_LENGTH == s->init_num);
1059         }
1060
1061     frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1062     frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1063     frag->msg_header.type = s->d1->w_msg_hdr.type;
1064     frag->msg_header.frag_off = 0;
1065     frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1066     frag->msg_header.is_ccs = is_ccs;
1067
1068     item = pitem_new(frag->msg_header.seq, frag);
1069     if ( item == NULL)
1070         {
1071         dtls1_hm_fragment_free(frag);
1072         return 0;
1073         }
1074
1075 #if 0
1076     fprintf( stderr, "buffered messge: \ttype = %xx\n", msg_buf->type);
1077     fprintf( stderr, "\t\t\t\t\tlen = %d\n", msg_buf->len);
1078     fprintf( stderr, "\t\t\t\t\tseq_num = %d\n", msg_buf->seq_num);
1079 #endif
1080
1081     pqueue_insert(s->d1->sent_messages, item);
1082     return 1;
1083     }
1084
1085 int
1086 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
1087     int *found)
1088     {
1089     int ret;
1090     /* XDTLS: for now assuming that read/writes are blocking */
1091     pitem *item;
1092     hm_fragment *frag ;
1093     unsigned long header_length;
1094
1095     /*
1096       OPENSSL_assert(s->init_num == 0);
1097       OPENSSL_assert(s->init_off == 0);
1098      */
1099
1100     /* XDTLS:  the requested message ought to be found, otherwise error */
1101     item = pqueue_find(s->d1->sent_messages, seq);
1102     if ( item == NULL)
1103         {
1104         fprintf(stderr, "retransmit:  message %d non-existant\n", seq);
1105         *found = 0;
1106         return 0;
1107         }
1108
1109     *found = 1;
1110     frag = (hm_fragment *)item->data;
1111
1112     if ( frag->msg_header.is_ccs)
1113         header_length = DTLS1_CCS_HEADER_LENGTH;
1114     else
1115         header_length = DTLS1_HM_HEADER_LENGTH;
1116
1117     memcpy(s->init_buf->data, frag->fragment,
1118         frag->msg_header.msg_len + header_length);
1119         s->init_num = frag->msg_header.msg_len + header_length;
1120
1121     dtls1_set_message_header_int(s, frag->msg_header.type,
1122         frag->msg_header.msg_len, frag->msg_header.seq, 0,
1123         frag->msg_header.frag_len);
1124
1125     s->d1->retransmitting = 1;
1126     ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1127         SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1128     s->d1->retransmitting = 0;
1129
1130     BIO_flush(SSL_get_wbio(s));
1131     return ret;
1132     }
1133
1134 /* call this function when the buffered messages are no longer needed */
1135 void
1136 dtls1_clear_record_buffer(SSL *s)
1137     {
1138     pitem *item;
1139
1140     for(item = pqueue_pop(s->d1->sent_messages);
1141         item != NULL; item = pqueue_pop(s->d1->sent_messages))
1142         {
1143         dtls1_hm_fragment_free((hm_fragment *)item->data);
1144         pitem_free(item);
1145         }
1146     }
1147
1148
1149 unsigned char *
1150 dtls1_set_message_header(SSL *s, unsigned char *p, unsigned char mt,
1151     unsigned long len, unsigned long frag_off, unsigned long frag_len)
1152     {
1153     if ( frag_off == 0)
1154         {
1155         s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1156         s->d1->next_handshake_write_seq++;
1157         }
1158
1159     dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1160         frag_off, frag_len);
1161
1162     return p += DTLS1_HM_HEADER_LENGTH;
1163     }
1164
1165
1166 /* don't actually do the writing, wait till the MTU has been retrieved */
1167 static void
1168 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1169     unsigned long len, unsigned short seq_num, unsigned long frag_off,
1170     unsigned long frag_len)
1171     {
1172     struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1173
1174     msg_hdr->type = mt;
1175     msg_hdr->msg_len = len;
1176     msg_hdr->seq = seq_num;
1177     msg_hdr->frag_off = frag_off;
1178     msg_hdr->frag_len = frag_len;
1179 }
1180
1181 static void
1182 dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1183         unsigned long frag_len)
1184     {
1185     struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1186
1187     msg_hdr->frag_off = frag_off;
1188     msg_hdr->frag_len = frag_len;
1189     }
1190
1191 static unsigned char *
1192 dtls1_write_message_header(SSL *s, unsigned char *p)
1193     {
1194     struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1195
1196     *p++ = msg_hdr->type;
1197     l2n3(msg_hdr->msg_len, p);
1198
1199     s2n(msg_hdr->seq, p);
1200     l2n3(msg_hdr->frag_off, p);
1201     l2n3(msg_hdr->frag_len, p);
1202
1203     return p;
1204     }
1205
1206 static unsigned int
1207 dtls1_min_mtu(void)
1208     {
1209     return
1210         g_probable_mtu[(sizeof(g_probable_mtu) /
1211            sizeof(g_probable_mtu[0])) - 1];
1212     }
1213
1214 static unsigned int
1215 dtls1_guess_mtu(unsigned int curr_mtu)
1216         {
1217         int i;
1218
1219         if ( curr_mtu == 0 )
1220                 return g_probable_mtu[0] ;
1221
1222         for ( i = 0; i < sizeof(g_probable_mtu)/sizeof(g_probable_mtu[0]); i++)
1223                 if ( curr_mtu > g_probable_mtu[i])
1224                         return g_probable_mtu[i];
1225
1226         return curr_mtu;
1227         }
1228
1229 void
1230 dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1231     {
1232     memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
1233     msg_hdr->type = *(data++);
1234     n2l3(data, msg_hdr->msg_len);
1235
1236     n2s(data, msg_hdr->seq);
1237     n2l3(data, msg_hdr->frag_off);
1238     n2l3(data, msg_hdr->frag_len);
1239     }
1240
1241 void
1242 dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
1243     {
1244     memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
1245
1246     ccs_hdr->type = *(data++);
1247     n2s(data, ccs_hdr->seq);
1248 }