ssl/d1_both.c

   1 /* ssl/d1_both.c */
   2 /*
   3  * DTLS implementation written by Nagendra Modadugu
   4  * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
   5  */
   6 /* ====================================================================
   7  * Copyright (c) 1998-2005 The OpenSSL Project.  All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  *
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  *
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in
  18  *    the documentation and/or other materials provided with the
  19  *    distribution.
  20  *
  21  * 3. All advertising materials mentioning features or use of this
  22  *    software must display the following acknowledgment:
  23  *    "This product includes software developed by the OpenSSL Project
  24  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
  25  *
  26  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  27  *    endorse or promote products derived from this software without
  28  *    prior written permission. For written permission, please contact
  29  *    openssl-core@openssl.org.
  30  *
  31  * 5. Products derived from this software may not be called "OpenSSL"
  32  *    nor may "OpenSSL" appear in their names without prior written
  33  *    permission of the OpenSSL Project.
  34  *
  35  * 6. Redistributions of any form whatsoever must retain the following
  36  *    acknowledgment:
  37  *    "This product includes software developed by the OpenSSL Project
  38  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  39  *
  40  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  41  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  43  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  44  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  45  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  46  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  47  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  49  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  50  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  51  * OF THE POSSIBILITY OF SUCH DAMAGE.
  52  * ====================================================================
  53  *
  54  * This product includes cryptographic software written by Eric Young
  55  * (eay@cryptsoft.com).  This product includes software written by Tim
  56  * Hudson (tjh@cryptsoft.com).
  57  *
  58  */
  59 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  60  * All rights reserved.
  61  *
  62  * This package is an SSL implementation written
  63  * by Eric Young (eay@cryptsoft.com).
  64  * The implementation was written so as to conform with Netscapes SSL.
  65  *
  66  * This library is free for commercial and non-commercial use as long as
  67  * the following conditions are aheared to.  The following conditions
  68  * apply to all code found in this distribution, be it the RC4, RSA,
  69  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  70  * included with this distribution is covered by the same copyright terms
  71  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  72  *
  73  * Copyright remains Eric Young's, and as such any Copyright notices in
  74  * the code are not to be removed.
  75  * If this package is used in a product, Eric Young should be given attribution
  76  * as the author of the parts of the library used.
  77  * This can be in the form of a textual message at program startup or
  78  * in documentation (online or textual) provided with the package.
  79  *
  80  * Redistribution and use in source and binary forms, with or without
  81  * modification, are permitted provided that the following conditions
  82  * are met:
  83  * 1. Redistributions of source code must retain the copyright
  84  *    notice, this list of conditions and the following disclaimer.
  85  * 2. Redistributions in binary form must reproduce the above copyright
  86  *    notice, this list of conditions and the following disclaimer in the
  87  *    documentation and/or other materials provided with the distribution.
  88  * 3. All advertising materials mentioning features or use of this software
  89  *    must display the following acknowledgement:
  90  *    "This product includes cryptographic software written by
  91  *     Eric Young (eay@cryptsoft.com)"
  92  *    The word 'cryptographic' can be left out if the rouines from the library
  93  *    being used are not cryptographic related :-).
  94  * 4. If you include any Windows specific code (or a derivative thereof) from
  95  *    the apps directory (application code) you must include an acknowledgement:
  96  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  97  *
  98  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  99  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 100  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 101  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 102  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 103  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 104  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 105  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 106  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 107  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 108  * SUCH DAMAGE.
 109  *
 110  * The licence and distribution terms for any publically available version or
 111  * derivative of this code cannot be changed.  i.e. this code cannot simply be
 112  * copied and put under another distribution licence
 113  * [including the GNU Public Licence.]
 114  */
 115
 116 #include <limits.h>
 117 #include <string.h>
 118 #include <stdio.h>
 119 #include "ssl_locl.h"
 120 #include <openssl/buffer.h>
 121 #include <openssl/rand.h>
 122 #include <openssl/objects.h>
 123 #include <openssl/evp.h>
 124 #include <openssl/x509.h>
 125
 126 #define RSMBLY_BITMASK_SIZE(msg_len) (((msg_len) + 7) / 8)
 127
 128 #define RSMBLY_BITMASK_MARK(bitmask, start, end) { \
 129                         if ((end) - (start) <= 8) { \
 130                                 long ii; \
 131                                 for (ii = (start); ii < (end); ii++) bitmask[((ii) >> 3)] |= (1 << ((ii) & 7)); \
 132                         } else { \
 133                                 long ii; \
 134                                 bitmask[((start) >> 3)] |= bitmask_start_values[((start) & 7)]; \
 135                                 for (ii = (((start) >> 3) + 1); ii < ((((end) - 1)) >> 3); ii++) bitmask[ii] = 0xff; \
 136                                 bitmask[(((end) - 1) >> 3)] |= bitmask_end_values[((end) & 7)]; \
 137                         } }
 138
 139 #define RSMBLY_BITMASK_IS_COMPLETE(bitmask, msg_len, is_complete) { \
 140                         long ii; \
 141                         OPENSSL_assert((msg_len) > 0); \
 142                         is_complete = 1; \
 143                         if (bitmask[(((msg_len) - 1) >> 3)] != bitmask_end_values[((msg_len) & 7)]) is_complete = 0; \
 144                         if (is_complete) for (ii = (((msg_len) - 1) >> 3) - 1; ii >= 0 ; ii--) \
 145                                 if (bitmask[ii] != 0xff) { is_complete = 0; break; } }
 146
 147 #if 0
 148 #define RSMBLY_BITMASK_PRINT(bitmask, msg_len) { \
 149                         long ii; \
 150                         printf("bitmask: "); for (ii = 0; ii < (msg_len); ii++) \
 151                         printf("%d ", (bitmask[ii >> 3] & (1 << (ii & 7))) >> (ii & 7)); \
 152                         printf("\n"); }
 153 #endif
 154
 155 static unsigned char bitmask_start_values[] = {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80};
 156 static unsigned char bitmask_end_values[]   = {0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f};
 157
 158 /* XDTLS:  figure out the right values */
 159 static unsigned int g_probable_mtu[] = {1500 - 28, 512 - 28, 256 - 28};
 160
 161 static unsigned int dtls1_guess_mtu(unsigned int curr_mtu);
 162 static void dtls1_fix_message_header(SSL *s, unsigned long frag_off,
 163         unsigned long frag_len);
 164 static unsigned char *dtls1_write_message_header(SSL *s,
 165         unsigned char *p);
 166 static void dtls1_set_message_header_int(SSL *s, unsigned char mt,
 167         unsigned long len, unsigned short seq_num, unsigned long frag_off,
 168         unsigned long frag_len);
 169 static long dtls1_get_message_fragment(SSL *s, int st1, int stn,
 170         long max, int *ok);
 171
 172 static hm_fragment *
 173 dtls1_hm_fragment_new(unsigned long frag_len, int reassembly)
 174         {
 175         hm_fragment *frag = NULL;
 176         unsigned char *buf = NULL;
 177         unsigned char *bitmask = NULL;
 178
 179         frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment));
 180         if ( frag == NULL)
 181                 return NULL;
 182
 183         if (frag_len)
 184                 {
 185                 buf = (unsigned char *)OPENSSL_malloc(frag_len);
 186                 if ( buf == NULL)
 187                         {
 188                         OPENSSL_free(frag);
 189                         return NULL;
 190                         }
 191                 }
 192
 193         /* zero length fragment gets zero frag->fragment */
 194         frag->fragment = buf;
 195
 196         /* Initialize reassembly bitmask if necessary */
 197         if (reassembly)
 198                 {
 199                 bitmask = (unsigned char *)OPENSSL_malloc(RSMBLY_BITMASK_SIZE(frag_len));
 200                 if (bitmask == NULL)
 201                         {
 202                         if (buf != NULL) OPENSSL_free(buf);
 203                         OPENSSL_free(frag);
 204                         return NULL;
 205                         }
 206                 memset(bitmask, 0, RSMBLY_BITMASK_SIZE(frag_len));
 207                 }
 208
 209         frag->reassembly = bitmask;
 210
 211         return frag;
 212         }
 213
 214 static void
 215 dtls1_hm_fragment_free(hm_fragment *frag)
 216         {
 217         if (frag->fragment) OPENSSL_free(frag->fragment);
 218         if (frag->reassembly) OPENSSL_free(frag->reassembly);
 219         OPENSSL_free(frag);
 220         }
 221
 222 /* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
 223 int dtls1_do_write(SSL *s, int type)
 224         {
 225         int ret;
 226         int curr_mtu;
 227         unsigned int len, frag_off, mac_size, blocksize;
 228
 229         /* AHA!  Figure out the MTU, and stick to the right size */
 230         if (s->d1->mtu < dtls1_min_mtu() && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
 231                 {
 232                 s->d1->mtu =
 233                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
 234
 235                 /* I've seen the kernel return bogus numbers when it doesn't know
 236                  * (initial write), so just make sure we have a reasonable number */
 237                 if (s->d1->mtu < dtls1_min_mtu())
 238                         {
 239                         s->d1->mtu = 0;
 240                         s->d1->mtu = dtls1_guess_mtu(s->d1->mtu);
 241                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
 242                                 s->d1->mtu, NULL);
 243                         }
 244                 }
 245 #if 0
 246         mtu = s->d1->mtu;
 247
 248         fprintf(stderr, "using MTU = %d\n", mtu);
 249
 250         mtu -= (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 251
 252         curr_mtu = mtu - BIO_wpending(SSL_get_wbio(s));
 253
 254         if ( curr_mtu > 0)
 255                 mtu = curr_mtu;
 256         else if ( ( ret = BIO_flush(SSL_get_wbio(s))) <= 0)
 257                 return ret;
 258
 259         if ( BIO_wpending(SSL_get_wbio(s)) + s->init_num >= mtu)
 260                 {
 261                 ret = BIO_flush(SSL_get_wbio(s));
 262                 if ( ret <= 0)
 263                         return ret;
 264                 mtu = s->d1->mtu - (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 265                 }
 266 #endif
 267
 268         OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu());  /* should have something reasonable now */
 269
 270         if ( s->init_off == 0  && type == SSL3_RT_HANDSHAKE)
 271                 OPENSSL_assert(s->init_num ==
 272                         (int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH);
 273
 274         if (s->write_hash)
 275                 mac_size = EVP_MD_CTX_size(s->write_hash);
 276         else
 277                 mac_size = 0;
 278
 279         if (s->enc_write_ctx &&
 280                 (EVP_CIPHER_mode( s->enc_write_ctx->cipher) & EVP_CIPH_CBC_MODE))
 281                 blocksize = 2 * EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
 282         else
 283                 blocksize = 0;
 284
 285         frag_off = 0;
 286         while( s->init_num)
 287                 {
 288                 curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) -
 289                         DTLS1_RT_HEADER_LENGTH - mac_size - blocksize;
 290
 291                 if ( curr_mtu <= DTLS1_HM_HEADER_LENGTH)
 292                         {
 293                         /* grr.. we could get an error if MTU picked was wrong */
 294                         ret = BIO_flush(SSL_get_wbio(s));
 295                         if ( ret <= 0)
 296                                 return ret;
 297                         curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH -
 298                                 mac_size - blocksize;
 299                         }
 300
 301                 if ( s->init_num > curr_mtu)
 302                         len = curr_mtu;
 303                 else
 304                         len = s->init_num;
 305
 306
 307                 /* XDTLS: this function is too long.  split out the CCS part */
 308                 if ( type == SSL3_RT_HANDSHAKE)
 309                         {
 310                         if ( s->init_off != 0)
 311                                 {
 312                                 OPENSSL_assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
 313                                 s->init_off -= DTLS1_HM_HEADER_LENGTH;
 314                                 s->init_num += DTLS1_HM_HEADER_LENGTH;
 315
 316                                 if ( s->init_num > curr_mtu)
 317                                         len = curr_mtu;
 318                                 else
 319                                         len = s->init_num;
 320                                 }
 321
 322                         dtls1_fix_message_header(s, frag_off,
 323                                 len - DTLS1_HM_HEADER_LENGTH);
 324
 325                         dtls1_write_message_header(s, (unsigned char *)&s->init_buf->data[s->init_off]);
 326
 327                         OPENSSL_assert(len >= DTLS1_HM_HEADER_LENGTH);
 328                         }
 329
 330                 ret=dtls1_write_bytes(s,type,&s->init_buf->data[s->init_off],
 331                         len);
 332                 if (ret < 0)
 333                         {
 334                         /* might need to update MTU here, but we don't know
 335                          * which previous packet caused the failure -- so can't
 336                          * really retransmit anything.  continue as if everything
 337                          * is fine and wait for an alert to handle the
 338                          * retransmit
 339                          */
 340                         if ( BIO_ctrl(SSL_get_wbio(s),
 341                                 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0 )
 342                                 s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
 343                                         BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
 344                         else
 345                                 return(-1);
 346                         }
 347                 else
 348                         {
 349
 350                         /* bad if this assert fails, only part of the handshake
 351                          * message got sent.  but why would this happen? */
 352                         OPENSSL_assert(len == (unsigned int)ret);
 353
 354                         if (type == SSL3_RT_HANDSHAKE && ! s->d1->retransmitting)
 355                                 {
 356                                 /* should not be done for 'Hello Request's, but in that case
 357                                  * we'll ignore the result anyway */
 358                                 unsigned char *p = (unsigned char *)&s->init_buf->data[s->init_off];
 359                                 const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
 360                                 int xlen;
 361
 362                                 if (frag_off == 0 && s->version != DTLS1_BAD_VER)
 363                                         {
 364                                         /* reconstruct message header is if it
 365                                          * is being sent in single fragment */
 366                                         *p++ = msg_hdr->type;
 367                                         l2n3(msg_hdr->msg_len,p);
 368                                         s2n (msg_hdr->seq,p);
 369                                         l2n3(0,p);
 370                                         l2n3(msg_hdr->msg_len,p);
 371                                         p  -= DTLS1_HM_HEADER_LENGTH;
 372                                         xlen = ret;
 373                                         }
 374                                 else
 375                                         {
 376                                         p  += DTLS1_HM_HEADER_LENGTH;
 377                                         xlen = ret - DTLS1_HM_HEADER_LENGTH;
 378                                         }
 379
 380                                 ssl3_finish_mac(s, p, xlen);
 381                                 }
 382
 383                         if (ret == s->init_num)
 384                                 {
 385                                 if (s->msg_callback)
 386                                         s->msg_callback(1, s->version, type, s->init_buf->data,
 387                                                 (size_t)(s->init_off + s->init_num), s,
 388                                                 s->msg_callback_arg);
 389
 390                                 s->init_off = 0;  /* done writing this message */
 391                                 s->init_num = 0;
 392
 393                                 return(1);
 394                                 }
 395                         s->init_off+=ret;
 396                         s->init_num-=ret;
 397                         frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
 398                         }
 399                 }
 400         return(0);
 401         }
 402
 403
 404 /* Obtain handshake message of message type 'mt' (any if mt == -1),
 405  * maximum acceptable body length 'max'.
 406  * Read an entire handshake message.  Handshake messages arrive in
 407  * fragments.
 408  */
 409 long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
 410         {
 411         int i, al;
 412         struct hm_header_st *msg_hdr;
 413         unsigned char *p;
 414         unsigned long msg_len;
 415
 416         /* s3->tmp is used to store messages that are unexpected, caused
 417          * by the absence of an optional handshake message */
 418         if (s->s3->tmp.reuse_message)
 419                 {
 420                 s->s3->tmp.reuse_message=0;
 421                 if ((mt >= 0) && (s->s3->tmp.message_type != mt))
 422                         {
 423                         al=SSL_AD_UNEXPECTED_MESSAGE;
 424                         SSLerr(SSL_F_DTLS1_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
 425                         goto f_err;
 426                         }
 427                 *ok=1;
 428                 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 429                 s->init_num = (int)s->s3->tmp.message_size;
 430                 return s->init_num;
 431                 }
 432
 433         msg_hdr = &s->d1->r_msg_hdr;
 434         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 435
 436 again:
 437         i = dtls1_get_message_fragment(s, st1, stn, max, ok);
 438         if ( i == DTLS1_HM_BAD_FRAGMENT ||
 439                 i == DTLS1_HM_FRAGMENT_RETRY)  /* bad fragment received */
 440                 goto again;
 441         else if ( i <= 0 && !*ok)
 442                 return i;
 443
 444         p = (unsigned char *)s->init_buf->data;
 445         msg_len = msg_hdr->msg_len;
 446
 447         /* reconstruct message header */
 448         *(p++) = msg_hdr->type;
 449         l2n3(msg_len,p);
 450         s2n (msg_hdr->seq,p);
 451         l2n3(0,p);
 452         l2n3(msg_len,p);
 453         if (s->version != DTLS1_BAD_VER) {
 454                 p       -= DTLS1_HM_HEADER_LENGTH;
 455                 msg_len += DTLS1_HM_HEADER_LENGTH;
 456         }
 457
 458         ssl3_finish_mac(s, p, msg_len);
 459         if (s->msg_callback)
 460                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 461                         p, msg_len,
 462                         s, s->msg_callback_arg);
 463
 464         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 465
 466         /* Don't change sequence numbers while listening */
 467         if (!s->d1->listen)
 468                 s->d1->handshake_read_seq++;
 469
 470         s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 471         return s->init_num;
 472
 473 f_err:
 474         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 475         *ok = 0;
 476         return -1;
 477         }
 478
 479
 480 static int dtls1_preprocess_fragment(SSL *s,struct hm_header_st *msg_hdr,int max)
 481         {
 482         size_t frag_off,frag_len,msg_len;
 483
 484         msg_len  = msg_hdr->msg_len;
 485         frag_off = msg_hdr->frag_off;
 486         frag_len = msg_hdr->frag_len;
 487
 488         /* sanity checking */
 489         if ( (frag_off+frag_len) > msg_len)
 490                 {
 491                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 492                 return SSL_AD_ILLEGAL_PARAMETER;
 493                 }
 494
 495         if ( (frag_off+frag_len) > (unsigned long)max)
 496                 {
 497                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 498                 return SSL_AD_ILLEGAL_PARAMETER;
 499                 }
 500
 501         if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */
 502                 {
 503                 /* msg_len is limited to 2^24, but is effectively checked
 504                  * against max above */
 505                 if (!BUF_MEM_grow_clean(s->init_buf,msg_len+DTLS1_HM_HEADER_LENGTH))
 506                         {
 507                         SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,ERR_R_BUF_LIB);
 508                         return SSL_AD_INTERNAL_ERROR;
 509                         }
 510
 511                 s->s3->tmp.message_size  = msg_len;
 512                 s->d1->r_msg_hdr.msg_len = msg_len;
 513                 s->s3->tmp.message_type  = msg_hdr->type;
 514                 s->d1->r_msg_hdr.type    = msg_hdr->type;
 515                 s->d1->r_msg_hdr.seq     = msg_hdr->seq;
 516                 }
 517         else if (msg_len != s->d1->r_msg_hdr.msg_len)
 518                 {
 519                 /* They must be playing with us! BTW, failure to enforce
 520                  * upper limit would open possibility for buffer overrun. */
 521                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 522                 return SSL_AD_ILLEGAL_PARAMETER;
 523                 }
 524
 525         return 0; /* no error */
 526         }
 527
 528
 529 static int
 530 dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok)
 531         {
 532         /* (0) check whether the desired fragment is available
 533          * if so:
 534          * (1) copy over the fragment to s->init_buf->data[]
 535          * (2) update s->init_num
 536          */
 537         pitem *item;
 538         hm_fragment *frag;
 539         int al;
 540
 541         *ok = 0;
 542         item = pqueue_peek(s->d1->buffered_messages);
 543         if ( item == NULL)
 544                 return 0;
 545
 546         frag = (hm_fragment *)item->data;
 547
 548         /* Don't return if reassembly still in progress */
 549         if (frag->reassembly != NULL)
 550                 return 0;
 551
 552         if ( s->d1->handshake_read_seq == frag->msg_header.seq)
 553                 {
 554                 unsigned long frag_len = frag->msg_header.frag_len;
 555                 pqueue_pop(s->d1->buffered_messages);
 556
 557                 al=dtls1_preprocess_fragment(s,&frag->msg_header,max);
 558
 559                 if (al==0) /* no alert */
 560                         {
 561                         unsigned char *p = (unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 562                         memcpy(&p[frag->msg_header.frag_off],
 563                                 frag->fragment,frag->msg_header.frag_len);
 564                         }
 565
 566                 dtls1_hm_fragment_free(frag);
 567                 pitem_free(item);
 568
 569                 if (al==0)
 570                         {
 571                         *ok = 1;
 572                         return frag_len;
 573                         }
 574
 575                 ssl3_send_alert(s,SSL3_AL_FATAL,al);
 576                 s->init_num = 0;
 577                 *ok = 0;
 578                 return -1;
 579                 }
 580         else
 581                 return 0;
 582         }
 583
 584
 585 static int
 586 dtls1_reassemble_fragment(SSL *s, struct hm_header_st* msg_hdr, int *ok)
 587         {
 588         hm_fragment *frag = NULL;
 589         pitem *item = NULL;
 590         int i = -1, is_complete;
 591         unsigned char seq64be[8];
 592         unsigned long frag_len = msg_hdr->frag_len, max_len;
 593
 594         if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
 595                 goto err;
 596
 597         /* Determine maximum allowed message size. Depends on (user set)
 598          * maximum certificate length, but 16k is minimum.
 599          */
 600         if (DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH < s->max_cert_list)
 601                 max_len = s->max_cert_list;
 602         else
 603                 max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
 604
 605         if ((msg_hdr->frag_off+frag_len) > max_len)
 606                 goto err;
 607
 608         /* Try to find item in queue */
 609         memset(seq64be,0,sizeof(seq64be));
 610         seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
 611         seq64be[7] = (unsigned char) msg_hdr->seq;
 612         item = pqueue_find(s->d1->buffered_messages, seq64be);
 613
 614         if (item == NULL)
 615                 {
 616                 frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
 617                 if ( frag == NULL)
 618                         goto err;
 619                 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 620                 frag->msg_header.frag_len = frag->msg_header.msg_len;
 621                 frag->msg_header.frag_off = 0;
 622                 }
 623         else
 624                 frag = (hm_fragment*) item->data;
 625
 626         /* If message is already reassembled, this must be a
 627          * retransmit and can be dropped.
 628          */
 629         if (frag->reassembly == NULL)
 630                 {
 631                 unsigned char devnull [256];
 632
 633                 while (frag_len)
 634                         {
 635                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 636                                 devnull,
 637                                 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
 638                         if (i<=0) goto err;
 639                         frag_len -= i;
 640                         }
 641                 return DTLS1_HM_FRAGMENT_RETRY;
 642                 }
 643
 644         /* read the body of the fragment (header has already been read */
 645         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 646                 frag->fragment + msg_hdr->frag_off,frag_len,0);
 647         if (i<=0 || (unsigned long)i!=frag_len)
 648                 goto err;
 649
 650         RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
 651                             (long)(msg_hdr->frag_off + frag_len));
 652
 653         RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
 654                                    is_complete);
 655
 656         if (is_complete)
 657                 {
 658                 OPENSSL_free(frag->reassembly);
 659                 frag->reassembly = NULL;
 660                 }
 661
 662         if (item == NULL)
 663                 {
 664                 memset(seq64be,0,sizeof(seq64be));
 665                 seq64be[6] = (unsigned char)(msg_hdr->seq>>8);
 666                 seq64be[7] = (unsigned char)(msg_hdr->seq);
 667
 668                 item = pitem_new(seq64be, frag);
 669                 if (item == NULL)
 670                         {
 671                         goto err;
 672                         i = -1;
 673                         }
 674
 675                 pqueue_insert(s->d1->buffered_messages, item);
 676                 }
 677
 678         return DTLS1_HM_FRAGMENT_RETRY;
 679
 680 err:
 681         if (frag != NULL) dtls1_hm_fragment_free(frag);
 682         if (item != NULL) OPENSSL_free(item);
 683         *ok = 0;
 684         return i;
 685         }
 686
 687
 688 static int
 689 dtls1_process_out_of_seq_message(SSL *s, struct hm_header_st* msg_hdr, int *ok)
 690 {
 691         int i=-1;
 692         hm_fragment *frag = NULL;
 693         pitem *item = NULL;
 694         unsigned char seq64be[8];
 695         unsigned long frag_len = msg_hdr->frag_len;
 696
 697         if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
 698                 goto err;
 699
 700         /* Try to find item in queue, to prevent duplicate entries */
 701         memset(seq64be,0,sizeof(seq64be));
 702         seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
 703         seq64be[7] = (unsigned char) msg_hdr->seq;
 704         item = pqueue_find(s->d1->buffered_messages, seq64be);
 705
 706         /* If we already have an entry and this one is a fragment,
 707          * don't discard it and rather try to reassemble it.
 708          */
 709         if (item != NULL && frag_len < msg_hdr->msg_len)
 710                 item = NULL;
 711
 712         /* Discard the message if sequence number was already there, is
 713          * too far in the future, already in the queue or if we received
 714          * a FINISHED before the SERVER_HELLO, which then must be a stale
 715          * retransmit.
 716          */
 717         if (msg_hdr->seq <= s->d1->handshake_read_seq ||
 718                 msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
 719                 (s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED))
 720                 {
 721                 unsigned char devnull [256];
 722
 723                 while (frag_len)
 724                         {
 725                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 726                                 devnull,
 727                                 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
 728                         if (i<=0) goto err;
 729                         frag_len -= i;
 730                         }
 731                 }
 732         else
 733                 {
 734                 if (frag_len && frag_len < msg_hdr->msg_len)
 735                         return dtls1_reassemble_fragment(s, msg_hdr, ok);
 736
 737                 frag = dtls1_hm_fragment_new(frag_len, 0);
 738                 if ( frag == NULL)
 739                         goto err;
 740
 741                 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 742
 743                 if (frag_len)
 744                         {
 745                         /* read the body of the fragment (header has already been read */
 746                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 747                                 frag->fragment,frag_len,0);
 748                         if (i<=0 || (unsigned long)i!=frag_len)
 749                                 goto err;
 750                         }
 751
 752                 memset(seq64be,0,sizeof(seq64be));
 753                 seq64be[6] = (unsigned char)(msg_hdr->seq>>8);
 754                 seq64be[7] = (unsigned char)(msg_hdr->seq);
 755
 756                 item = pitem_new(seq64be, frag);
 757                 if ( item == NULL)
 758                         goto err;
 759
 760                 pqueue_insert(s->d1->buffered_messages, item);
 761                 }
 762
 763         return DTLS1_HM_FRAGMENT_RETRY;
 764
 765 err:
 766         if ( frag != NULL) dtls1_hm_fragment_free(frag);
 767         if ( item != NULL) OPENSSL_free(item);
 768         *ok = 0;
 769         return i;
 770         }
 771
 772
 773 static long
 774 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
 775         {
 776         unsigned char wire[DTLS1_HM_HEADER_LENGTH];
 777         unsigned long len, frag_off, frag_len;
 778         int i,al;
 779         struct hm_header_st msg_hdr;
 780
 781         /* see if we have the required fragment already */
 782         if ((frag_len = dtls1_retrieve_buffered_fragment(s,max,ok)) || *ok)
 783                 {
 784                 if (*ok)        s->init_num = frag_len;
 785                 return frag_len;
 786                 }
 787
 788         /* read handshake message header */
 789         i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,wire,
 790                 DTLS1_HM_HEADER_LENGTH, 0);
 791         if (i <= 0)     /* nbio, or an error */
 792                 {
 793                 s->rwstate=SSL_READING;
 794                 *ok = 0;
 795                 return i;
 796                 }
 797         /* Handshake fails if message header is incomplete */
 798         if (i != DTLS1_HM_HEADER_LENGTH)
 799                 {
 800                 al=SSL_AD_UNEXPECTED_MESSAGE;
 801                 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 802                 goto f_err;
 803                 }
 804
 805         /* parse the message fragment header */
 806         dtls1_get_message_header(wire, &msg_hdr);
 807
 808         /*
 809          * if this is a future (or stale) message it gets buffered
 810          * (or dropped)--no further processing at this time
 811          * While listening, we accept seq 1 (ClientHello with cookie)
 812          * although we're still expecting seq 0 (ClientHello)
 813          */
 814         if (msg_hdr.seq != s->d1->handshake_read_seq && !(s->d1->listen && msg_hdr.seq == 1))
 815                 return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
 816
 817         len = msg_hdr.msg_len;
 818         frag_off = msg_hdr.frag_off;
 819         frag_len = msg_hdr.frag_len;
 820
 821         if (frag_len && frag_len < len)
 822                 return dtls1_reassemble_fragment(s, &msg_hdr, ok);
 823
 824         if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
 825                 wire[0] == SSL3_MT_HELLO_REQUEST)
 826                 {
 827                 /* The server may always send 'Hello Request' messages --
 828                  * we are doing a handshake anyway now, so ignore them
 829                  * if their format is correct. Does not count for
 830                  * 'Finished' MAC. */
 831                 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0)
 832                         {
 833                         if (s->msg_callback)
 834                                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 835                                         wire, DTLS1_HM_HEADER_LENGTH, s,
 836                                         s->msg_callback_arg);
 837
 838                         s->init_num = 0;
 839                         return dtls1_get_message_fragment(s, st1, stn,
 840                                 max, ok);
 841                         }
 842                 else /* Incorrectly formated Hello request */
 843                         {
 844                         al=SSL_AD_UNEXPECTED_MESSAGE;
 845                         SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 846                         goto f_err;
 847                         }
 848                 }
 849
 850         if ((al=dtls1_preprocess_fragment(s,&msg_hdr,max)))
 851                 goto f_err;
 852
 853         /* XDTLS:  ressurect this when restart is in place */
 854         s->state=stn;
 855
 856         if ( frag_len > 0)
 857                 {
 858                 unsigned char *p=(unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 859
 860                 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 861                         &p[frag_off],frag_len,0);
 862                 /* XDTLS:  fix this--message fragments cannot span multiple packets */
 863                 if (i <= 0)
 864                         {
 865                         s->rwstate=SSL_READING;
 866                         *ok = 0;
 867                         return i;
 868                         }
 869                 }
 870         else
 871                 i = 0;
 872
 873         /* XDTLS:  an incorrectly formatted fragment should cause the
 874          * handshake to fail */
 875         if (i != (int)frag_len)
 876                 {
 877                 al=SSL3_AD_ILLEGAL_PARAMETER;
 878                 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL3_AD_ILLEGAL_PARAMETER);
 879                 goto f_err;
 880                 }
 881
 882         *ok = 1;
 883
 884         /* Note that s->init_num is *not* used as current offset in
 885          * s->init_buf->data, but as a counter summing up fragments'
 886          * lengths: as soon as they sum up to handshake packet
 887          * length, we assume we have got all the fragments. */
 888         s->init_num = frag_len;
 889         return frag_len;
 890
 891 f_err:
 892         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 893         s->init_num = 0;
 894
 895         *ok=0;
 896         return(-1);
 897         }
 898
 899 /* for these 2 messages, we need to
 900  * ssl->enc_read_ctx                    re-init
 901  * ssl->s3->read_sequence               zero
 902  * ssl->s3->read_mac_secret             re-init
 903  * ssl->session->read_sym_enc           assign
 904  * ssl->session->read_compression       assign
 905  * ssl->session->read_hash              assign
 906  */
 907 int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
 908         {
 909         unsigned char *p;
 910
 911         if (s->state == a)
 912                 {
 913                 p=(unsigned char *)s->init_buf->data;
 914                 *p++=SSL3_MT_CCS;
 915                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
 916                 s->init_num=DTLS1_CCS_HEADER_LENGTH;
 917
 918                 if (s->version == DTLS1_BAD_VER) {
 919                         s->d1->next_handshake_write_seq++;
 920                         s2n(s->d1->handshake_write_seq,p);
 921                         s->init_num+=2;
 922                 }
 923
 924                 s->init_off=0;
 925
 926                 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
 927                         s->d1->handshake_write_seq, 0, 0);
 928
 929                 /* buffer the message to handle re-xmits */
 930                 dtls1_buffer_message(s, 1);
 931
 932                 s->state=b;
 933                 }
 934
 935         /* SSL3_ST_CW_CHANGE_B */
 936         return(dtls1_do_write(s,SSL3_RT_CHANGE_CIPHER_SPEC));
 937         }
 938
 939 int dtls1_read_failed(SSL *s, int code)
 940         {
 941         if ( code > 0)
 942                 {
 943                 fprintf( stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
 944                 return 1;
 945                 }
 946
 947         if (!dtls1_is_timer_expired(s))
 948                 {
 949                 /* not a timeout, none of our business,
 950                    let higher layers handle this.  in fact it's probably an error */
 951                 return code;
 952                 }
 953
 954 #ifndef OPENSSL_NO_HEARTBEATS
 955         if (!SSL_in_init(s) && !s->tlsext_hb_pending)  /* done, no need to send a retransmit */
 956 #else
 957         if (!SSL_in_init(s))  /* done, no need to send a retransmit */
 958 #endif
 959                 {
 960                 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
 961                 return code;
 962                 }
 963
 964 #if 0 /* for now, each alert contains only one record number */
 965         item = pqueue_peek(state->rcvd_records);
 966         if ( item )
 967                 {
 968                 /* send an alert immediately for all the missing records */
 969                 }
 970         else
 971 #endif
 972
 973 #if 0  /* no more alert sending, just retransmit the last set of messages */
 974         if ( state->timeout.read_timeouts >= DTLS1_TMO_READ_COUNT)
 975                 ssl3_send_alert(s,SSL3_AL_WARNING,
 976                         DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
 977 #endif
 978
 979         return dtls1_handle_timeout(s);
 980         }
 981
 982 int
 983 dtls1_get_queue_priority(unsigned short seq, int is_ccs)
 984         {
 985         /* The index of the retransmission queue actually is the message sequence number,
 986          * since the queue only contains messages of a single handshake. However, the
 987          * ChangeCipherSpec has no message sequence number and so using only the sequence
 988          * will result in the CCS and Finished having the same index. To prevent this,
 989          * the sequence number is multiplied by 2. In case of a CCS 1 is subtracted.
 990          * This does not only differ CSS and Finished, it also maintains the order of the
 991          * index (important for priority queues) and fits in the unsigned short variable.
 992          */
 993         return seq * 2 - is_ccs;
 994         }
 995
 996 int
 997 dtls1_retransmit_buffered_messages(SSL *s)
 998         {
 999         pqueue sent = s->d1->sent_messages;
1000         piterator iter;
1001         pitem *item;
1002         hm_fragment *frag;
1003         int found = 0;
1004
1005         iter = pqueue_iterator(sent);
1006
1007         for ( item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter))
1008                 {
1009                 frag = (hm_fragment *)item->data;
1010                         if ( dtls1_retransmit_message(s,
1011                                 (unsigned short)dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs),
1012                                 0, &found) <= 0 && found)
1013                         {
1014                         fprintf(stderr, "dtls1_retransmit_message() failed\n");
1015                         return -1;
1016                         }
1017                 }
1018
1019         return 1;
1020         }
1021
1022 int
1023 dtls1_buffer_message(SSL *s, int is_ccs)
1024         {
1025         pitem *item;
1026         hm_fragment *frag;
1027         unsigned char seq64be[8];
1028
1029         /* this function is called immediately after a message has
1030          * been serialized */
1031         OPENSSL_assert(s->init_off == 0);
1032
1033         frag = dtls1_hm_fragment_new(s->init_num, 0);
1034
1035         memcpy(frag->fragment, s->init_buf->data, s->init_num);
1036
1037         if ( is_ccs)
1038                 {
1039                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1040                                ((s->version==DTLS1_VERSION)?DTLS1_CCS_HEADER_LENGTH:3) == (unsigned int)s->init_num);
1041                 }
1042         else
1043                 {
1044                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1045                         DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
1046                 }
1047
1048         frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1049         frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1050         frag->msg_header.type = s->d1->w_msg_hdr.type;
1051         frag->msg_header.frag_off = 0;
1052         frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1053         frag->msg_header.is_ccs = is_ccs;
1054
1055         /* save current state*/
1056         frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
1057         frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
1058         frag->msg_header.saved_retransmit_state.compress = s->compress;
1059         frag->msg_header.saved_retransmit_state.session = s->session;
1060         frag->msg_header.saved_retransmit_state.epoch = s->d1->w_epoch;
1061
1062         memset(seq64be,0,sizeof(seq64be));
1063         seq64be[6] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1064                                                                                                                   frag->msg_header.is_ccs)>>8);
1065         seq64be[7] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1066                                                                                                                   frag->msg_header.is_ccs));
1067
1068         item = pitem_new(seq64be, 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         unsigned char seq64be[8];
1095         struct dtls1_retransmit_state saved_state;
1096         unsigned char save_write_sequence[8];
1097
1098         /*
1099           OPENSSL_assert(s->init_num == 0);
1100           OPENSSL_assert(s->init_off == 0);
1101          */
1102
1103         /* XDTLS:  the requested message ought to be found, otherwise error */
1104         memset(seq64be,0,sizeof(seq64be));
1105         seq64be[6] = (unsigned char)(seq>>8);
1106         seq64be[7] = (unsigned char)seq;
1107
1108         item = pqueue_find(s->d1->sent_messages, seq64be);
1109         if ( item == NULL)
1110                 {
1111                 fprintf(stderr, "retransmit:  message %d non-existant\n", seq);
1112                 *found = 0;
1113                 return 0;
1114                 }
1115
1116         *found = 1;
1117         frag = (hm_fragment *)item->data;
1118
1119         if ( frag->msg_header.is_ccs)
1120                 header_length = DTLS1_CCS_HEADER_LENGTH;
1121         else
1122                 header_length = DTLS1_HM_HEADER_LENGTH;
1123
1124         memcpy(s->init_buf->data, frag->fragment,
1125                 frag->msg_header.msg_len + header_length);
1126                 s->init_num = frag->msg_header.msg_len + header_length;
1127
1128         dtls1_set_message_header_int(s, frag->msg_header.type,
1129                 frag->msg_header.msg_len, frag->msg_header.seq, 0,
1130                 frag->msg_header.frag_len);
1131
1132         /* save current state */
1133         saved_state.enc_write_ctx = s->enc_write_ctx;
1134         saved_state.write_hash = s->write_hash;
1135         saved_state.compress = s->compress;
1136         saved_state.session = s->session;
1137         saved_state.epoch = s->d1->w_epoch;
1138         saved_state.epoch = s->d1->w_epoch;
1139
1140         s->d1->retransmitting = 1;
1141
1142         /* restore state in which the message was originally sent */
1143         s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
1144         s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
1145         s->compress = frag->msg_header.saved_retransmit_state.compress;
1146         s->session = frag->msg_header.saved_retransmit_state.session;
1147         s->d1->w_epoch = frag->msg_header.saved_retransmit_state.epoch;
1148
1149         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1150         {
1151                 memcpy(save_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1152                 memcpy(s->s3->write_sequence, s->d1->last_write_sequence, sizeof(s->s3->write_sequence));
1153         }
1154
1155         ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1156                                                  SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1157
1158         /* restore current state */
1159         s->enc_write_ctx = saved_state.enc_write_ctx;
1160         s->write_hash = saved_state.write_hash;
1161         s->compress = saved_state.compress;
1162         s->session = saved_state.session;
1163         s->d1->w_epoch = saved_state.epoch;
1164
1165         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1166         {
1167                 memcpy(s->d1->last_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1168                 memcpy(s->s3->write_sequence, save_write_sequence, sizeof(s->s3->write_sequence));
1169         }
1170
1171         s->d1->retransmitting = 0;
1172
1173         (void)BIO_flush(SSL_get_wbio(s));
1174         return ret;
1175         }
1176
1177 /* call this function when the buffered messages are no longer needed */
1178 void
1179 dtls1_clear_record_buffer(SSL *s)
1180         {
1181         pitem *item;
1182
1183         for(item = pqueue_pop(s->d1->sent_messages);
1184                 item != NULL; item = pqueue_pop(s->d1->sent_messages))
1185                 {
1186                 dtls1_hm_fragment_free((hm_fragment *)item->data);
1187                 pitem_free(item);
1188                 }
1189         }
1190
1191
1192 unsigned char *
1193 dtls1_set_message_header(SSL *s, unsigned char *p, unsigned char mt,
1194                         unsigned long len, unsigned long frag_off, unsigned long frag_len)
1195         {
1196         /* Don't change sequence numbers while listening */
1197         if (frag_off == 0 && !s->d1->listen)
1198                 {
1199                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1200                 s->d1->next_handshake_write_seq++;
1201                 }
1202
1203         dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1204                 frag_off, frag_len);
1205
1206         return p += DTLS1_HM_HEADER_LENGTH;
1207         }
1208
1209
1210 /* don't actually do the writing, wait till the MTU has been retrieved */
1211 static void
1212 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1213                             unsigned long len, unsigned short seq_num, unsigned long frag_off,
1214                             unsigned long frag_len)
1215         {
1216         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1217
1218         msg_hdr->type = mt;
1219         msg_hdr->msg_len = len;
1220         msg_hdr->seq = seq_num;
1221         msg_hdr->frag_off = frag_off;
1222         msg_hdr->frag_len = frag_len;
1223         }
1224
1225 static void
1226 dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1227                         unsigned long frag_len)
1228         {
1229         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1230
1231         msg_hdr->frag_off = frag_off;
1232         msg_hdr->frag_len = frag_len;
1233         }
1234
1235 static unsigned char *
1236 dtls1_write_message_header(SSL *s, unsigned char *p)
1237         {
1238         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1239
1240         *p++ = msg_hdr->type;
1241         l2n3(msg_hdr->msg_len, p);
1242
1243         s2n(msg_hdr->seq, p);
1244         l2n3(msg_hdr->frag_off, p);
1245         l2n3(msg_hdr->frag_len, p);
1246
1247         return p;
1248         }
1249
1250 unsigned int
1251 dtls1_min_mtu(void)
1252         {
1253         return (g_probable_mtu[(sizeof(g_probable_mtu) /
1254                 sizeof(g_probable_mtu[0])) - 1]);
1255         }
1256
1257 static unsigned int
1258 dtls1_guess_mtu(unsigned int curr_mtu)
1259         {
1260         unsigned int i;
1261
1262         if ( curr_mtu == 0 )
1263                 return g_probable_mtu[0] ;
1264
1265         for ( i = 0; i < sizeof(g_probable_mtu)/sizeof(g_probable_mtu[0]); i++)
1266                 if ( curr_mtu > g_probable_mtu[i])
1267                         return g_probable_mtu[i];
1268
1269         return curr_mtu;
1270         }
1271
1272 void
1273 dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1274         {
1275         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
1276         msg_hdr->type = *(data++);
1277         n2l3(data, msg_hdr->msg_len);
1278
1279         n2s(data, msg_hdr->seq);
1280         n2l3(data, msg_hdr->frag_off);
1281         n2l3(data, msg_hdr->frag_len);
1282         }
1283
1284 void
1285 dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
1286         {
1287         memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
1288
1289         ccs_hdr->type = *(data++);
1290         }
1291
1292 int dtls1_shutdown(SSL *s)
1293         {
1294         int ret;
1295 #ifndef OPENSSL_NO_SCTP
1296         if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
1297             !(s->shutdown & SSL_SENT_SHUTDOWN))
1298                 {
1299                 ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
1300                 if (ret < 0) return -1;
1301
1302                 if (ret == 0)
1303                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1, NULL);
1304                 }
1305 #endif
1306         ret = ssl3_shutdown(s);
1307 #ifndef OPENSSL_NO_SCTP
1308         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
1309 #endif
1310         return ret;
1311         }
1312
1313 #ifndef OPENSSL_NO_HEARTBEATS
1314 int
1315 dtls1_process_heartbeat(SSL *s)
1316         {
1317         unsigned char *p = &s->s3->rrec.data[0], *pl;
1318         unsigned short hbtype;
1319         unsigned int payload;
1320         unsigned int padding = 16; /* Use minimum padding */
1321
1322         /* Read type and payload length first */
1323         hbtype = *p++;
1324         n2s(p, payload);
1325         pl = p;
1326
1327         if (s->msg_callback)
1328                 s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
1329                         &s->s3->rrec.data[0], s->s3->rrec.length,
1330                         s, s->msg_callback_arg);
1331
1332         if (hbtype == TLS1_HB_REQUEST)
1333                 {
1334                 unsigned char *buffer, *bp;
1335                 int r;
1336
1337                 /* Allocate memory for the response, size is 1 byte
1338                  * message type, plus 2 bytes payload length, plus
1339                  * payload, plus padding
1340                  */
1341                 buffer = OPENSSL_malloc(1 + 2 + payload + padding);
1342                 bp = buffer;
1343
1344                 /* Enter response type, length and copy payload */
1345                 *bp++ = TLS1_HB_RESPONSE;
1346                 s2n(payload, bp);
1347                 memcpy(bp, pl, payload);
1348                 bp += payload;
1349                 /* Random padding */
1350                 RAND_pseudo_bytes(bp, padding);
1351
1352                 r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, 3 + payload + padding);
1353
1354                 if (r >= 0 && s->msg_callback)
1355                         s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1356                                 buffer, 3 + payload + padding,
1357                                 s, s->msg_callback_arg);
1358
1359                 OPENSSL_free(buffer);
1360
1361                 if (r < 0)
1362                         return r;
1363                 }
1364         else if (hbtype == TLS1_HB_RESPONSE)
1365                 {
1366                 unsigned int seq;
1367
1368                 /* We only send sequence numbers (2 bytes unsigned int),
1369                  * and 16 random bytes, so we just try to read the
1370                  * sequence number */
1371                 n2s(pl, seq);
1372
1373                 if (payload == 18 && seq == s->tlsext_hb_seq)
1374                         {
1375                         dtls1_stop_timer(s);
1376                         s->tlsext_hb_seq++;
1377                         s->tlsext_hb_pending = 0;
1378                         }
1379                 }
1380
1381         return 0;
1382         }
1383
1384 int
1385 dtls1_heartbeat(SSL *s)
1386         {
1387         unsigned char *buf, *p;
1388         int ret;
1389         unsigned int payload = 18; /* Sequence number + random bytes */
1390         unsigned int padding = 16; /* Use minimum padding */
1391
1392         /* Only send if peer supports and accepts HB requests... */
1393         if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
1394             s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS)
1395                 {
1396                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
1397                 return -1;
1398                 }
1399
1400         /* ...and there is none in flight yet... */
1401         if (s->tlsext_hb_pending)
1402                 {
1403                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PENDING);
1404                 return -1;
1405                 }
1406
1407         /* ...and no handshake in progress. */
1408         if (SSL_in_init(s) || s->in_handshake)
1409                 {
1410                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_UNEXPECTED_MESSAGE);
1411                 return -1;
1412                 }
1413
1414         /* Check if padding is too long, payload and padding
1415          * must not exceed 2^14 - 3 = 16381 bytes in total.
1416          */
1417         OPENSSL_assert(payload + padding <= 16381);
1418
1419         /* Create HeartBeat message, we just use a sequence number
1420          * as payload to distuingish different messages and add
1421          * some random stuff.
1422          *  - Message Type, 1 byte
1423          *  - Payload Length, 2 bytes (unsigned int)
1424          *  - Payload, the sequence number (2 bytes uint)
1425          *  - Payload, random bytes (16 bytes uint)
1426          *  - Padding
1427          */
1428         buf = OPENSSL_malloc(1 + 2 + payload + padding);
1429         p = buf;
1430         /* Message Type */
1431         *p++ = TLS1_HB_REQUEST;
1432         /* Payload length (18 bytes here) */
1433         s2n(payload, p);
1434         /* Sequence number */
1435         s2n(s->tlsext_hb_seq, p);
1436         /* 16 random bytes */
1437         RAND_pseudo_bytes(p, 16);
1438         p += 16;
1439         /* Random padding */
1440         RAND_pseudo_bytes(p, padding);
1441
1442         ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
1443         if (ret >= 0)
1444                 {
1445                 if (s->msg_callback)
1446                         s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1447                                 buf, 3 + payload + padding,
1448                                 s, s->msg_callback_arg);
1449
1450                 dtls1_start_timer(s);
1451                 s->tlsext_hb_pending = 1;
1452                 }
1453
1454         OPENSSL_free(buf);
1455
1456         return ret;
1457         }
1458 #endif