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 const 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 void dtls1_hm_fragment_free(hm_fragment *frag)
 215         {
 216
 217         if (frag->msg_header.is_ccs)
 218                 {
 219                 EVP_CIPHER_CTX_free(frag->msg_header.saved_retransmit_state.enc_write_ctx);
 220                 EVP_MD_CTX_destroy(frag->msg_header.saved_retransmit_state.write_hash);
 221                 }
 222         if (frag->fragment) OPENSSL_free(frag->fragment);
 223         if (frag->reassembly) OPENSSL_free(frag->reassembly);
 224         OPENSSL_free(frag);
 225         }
 226
 227 /* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
 228 int dtls1_do_write(SSL *s, int type)
 229         {
 230         int ret;
 231         int curr_mtu;
 232         unsigned int len, frag_off, mac_size, blocksize;
 233
 234         /* AHA!  Figure out the MTU, and stick to the right size */
 235         if (s->d1->mtu < dtls1_min_mtu() && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
 236                 {
 237                 s->d1->mtu =
 238                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
 239
 240                 /* I've seen the kernel return bogus numbers when it doesn't know
 241                  * (initial write), so just make sure we have a reasonable number */
 242                 if (s->d1->mtu < dtls1_min_mtu())
 243                         {
 244                         s->d1->mtu = 0;
 245                         s->d1->mtu = dtls1_guess_mtu(s->d1->mtu);
 246                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
 247                                 s->d1->mtu, NULL);
 248                         }
 249                 }
 250 #if 0
 251         mtu = s->d1->mtu;
 252
 253         fprintf(stderr, "using MTU = %d\n", mtu);
 254
 255         mtu -= (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 256
 257         curr_mtu = mtu - BIO_wpending(SSL_get_wbio(s));
 258
 259         if ( curr_mtu > 0)
 260                 mtu = curr_mtu;
 261         else if ( ( ret = BIO_flush(SSL_get_wbio(s))) <= 0)
 262                 return ret;
 263
 264         if ( BIO_wpending(SSL_get_wbio(s)) + s->init_num >= mtu)
 265                 {
 266                 ret = BIO_flush(SSL_get_wbio(s));
 267                 if ( ret <= 0)
 268                         return ret;
 269                 mtu = s->d1->mtu - (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 270                 }
 271 #endif
 272
 273         OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu());  /* should have something reasonable now */
 274
 275         if ( s->init_off == 0  && type == SSL3_RT_HANDSHAKE)
 276                 OPENSSL_assert(s->init_num ==
 277                         (int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH);
 278
 279         if (s->write_hash)
 280                 {
 281                 if (s->enc_write_ctx && EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_GCM_MODE)
 282                         mac_size = 0;
 283                 else
 284                         mac_size = EVP_MD_CTX_size(s->write_hash);
 285                 }
 286         else
 287                 mac_size = 0;
 288
 289         if (s->enc_write_ctx &&
 290                 (EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_CBC_MODE))
 291                 blocksize = 2 * EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
 292         else
 293                 blocksize = 0;
 294
 295         frag_off = 0;
 296         while( s->init_num)
 297                 {
 298                 curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) -
 299                         DTLS1_RT_HEADER_LENGTH - mac_size - blocksize;
 300
 301                 if ( curr_mtu <= DTLS1_HM_HEADER_LENGTH)
 302                         {
 303                         /* grr.. we could get an error if MTU picked was wrong */
 304                         ret = BIO_flush(SSL_get_wbio(s));
 305                         if ( ret <= 0)
 306                                 return ret;
 307                         curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH -
 308                                 mac_size - blocksize;
 309                         }
 310
 311                 if ( s->init_num > curr_mtu)
 312                         len = curr_mtu;
 313                 else
 314                         len = s->init_num;
 315
 316
 317                 /* XDTLS: this function is too long.  split out the CCS part */
 318                 if ( type == SSL3_RT_HANDSHAKE)
 319                         {
 320                         if ( s->init_off != 0)
 321                                 {
 322                                 OPENSSL_assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
 323                                 s->init_off -= DTLS1_HM_HEADER_LENGTH;
 324                                 s->init_num += DTLS1_HM_HEADER_LENGTH;
 325
 326                                 if ( s->init_num > curr_mtu)
 327                                         len = curr_mtu;
 328                                 else
 329                                         len = s->init_num;
 330                                 }
 331
 332                         if ( len < DTLS1_HM_HEADER_LENGTH )
 333                                 {
 334                                 /*
 335                                  * len is so small that we really can't do anything sensible
 336                                  * so fail
 337                                  */
 338                                 return -1;
 339                                 }
 340                         dtls1_fix_message_header(s, frag_off,
 341                                 len - DTLS1_HM_HEADER_LENGTH);
 342
 343                         dtls1_write_message_header(s, (unsigned char *)&s->init_buf->data[s->init_off]);
 344                         }
 345
 346                 ret=dtls1_write_bytes(s,type,&s->init_buf->data[s->init_off],
 347                         len);
 348                 if (ret < 0)
 349                         {
 350                         /* might need to update MTU here, but we don't know
 351                          * which previous packet caused the failure -- so can't
 352                          * really retransmit anything.  continue as if everything
 353                          * is fine and wait for an alert to handle the
 354                          * retransmit
 355                          */
 356                         if ( BIO_ctrl(SSL_get_wbio(s),
 357                                 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0 )
 358                                 s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
 359                                         BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
 360                         else
 361                                 return(-1);
 362                         }
 363                 else
 364                         {
 365
 366                         /* bad if this assert fails, only part of the handshake
 367                          * message got sent.  but why would this happen? */
 368                         OPENSSL_assert(len == (unsigned int)ret);
 369
 370                         if (type == SSL3_RT_HANDSHAKE && ! s->d1->retransmitting)
 371                                 {
 372                                 /* should not be done for 'Hello Request's, but in that case
 373                                  * we'll ignore the result anyway */
 374                                 unsigned char *p = (unsigned char *)&s->init_buf->data[s->init_off];
 375                                 const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
 376                                 int xlen;
 377
 378                                 if (frag_off == 0 && s->version != DTLS1_BAD_VER)
 379                                         {
 380                                         /* reconstruct message header is if it
 381                                          * is being sent in single fragment */
 382                                         *p++ = msg_hdr->type;
 383                                         l2n3(msg_hdr->msg_len,p);
 384                                         s2n (msg_hdr->seq,p);
 385                                         l2n3(0,p);
 386                                         l2n3(msg_hdr->msg_len,p);
 387                                         p  -= DTLS1_HM_HEADER_LENGTH;
 388                                         xlen = ret;
 389                                         }
 390                                 else
 391                                         {
 392                                         p  += DTLS1_HM_HEADER_LENGTH;
 393                                         xlen = ret - DTLS1_HM_HEADER_LENGTH;
 394                                         }
 395
 396                                 ssl3_finish_mac(s, p, xlen);
 397                                 }
 398
 399                         if (ret == s->init_num)
 400                                 {
 401                                 if (s->msg_callback)
 402                                         s->msg_callback(1, s->version, type, s->init_buf->data,
 403                                                 (size_t)(s->init_off + s->init_num), s,
 404                                                 s->msg_callback_arg);
 405
 406                                 s->init_off = 0;  /* done writing this message */
 407                                 s->init_num = 0;
 408
 409                                 return(1);
 410                                 }
 411                         s->init_off+=ret;
 412                         s->init_num-=ret;
 413                         frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
 414                         }
 415                 }
 416         return(0);
 417         }
 418
 419
 420 /* Obtain handshake message of message type 'mt' (any if mt == -1),
 421  * maximum acceptable body length 'max'.
 422  * Read an entire handshake message.  Handshake messages arrive in
 423  * fragments.
 424  */
 425 long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
 426         {
 427         int i, al;
 428         struct hm_header_st *msg_hdr;
 429         unsigned char *p;
 430         unsigned long msg_len;
 431
 432         /* s3->tmp is used to store messages that are unexpected, caused
 433          * by the absence of an optional handshake message */
 434         if (s->s3->tmp.reuse_message)
 435                 {
 436                 s->s3->tmp.reuse_message=0;
 437                 if ((mt >= 0) && (s->s3->tmp.message_type != mt))
 438                         {
 439                         al=SSL_AD_UNEXPECTED_MESSAGE;
 440                         SSLerr(SSL_F_DTLS1_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
 441                         goto f_err;
 442                         }
 443                 *ok=1;
 444                 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 445                 s->init_num = (int)s->s3->tmp.message_size;
 446                 return s->init_num;
 447                 }
 448
 449         msg_hdr = &s->d1->r_msg_hdr;
 450         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 451
 452 again:
 453         i = dtls1_get_message_fragment(s, st1, stn, max, ok);
 454         if ( i == DTLS1_HM_BAD_FRAGMENT ||
 455                 i == DTLS1_HM_FRAGMENT_RETRY)  /* bad fragment received */
 456                 goto again;
 457         else if ( i <= 0 && !*ok)
 458                 return i;
 459
 460         p = (unsigned char *)s->init_buf->data;
 461         msg_len = msg_hdr->msg_len;
 462
 463         /* reconstruct message header */
 464         *(p++) = msg_hdr->type;
 465         l2n3(msg_len,p);
 466         s2n (msg_hdr->seq,p);
 467         l2n3(0,p);
 468         l2n3(msg_len,p);
 469         if (s->version != DTLS1_BAD_VER) {
 470                 p       -= DTLS1_HM_HEADER_LENGTH;
 471                 msg_len += DTLS1_HM_HEADER_LENGTH;
 472         }
 473
 474         ssl3_finish_mac(s, p, msg_len);
 475         if (s->msg_callback)
 476                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 477                         p, msg_len,
 478                         s, s->msg_callback_arg);
 479
 480         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 481
 482         /* Don't change sequence numbers while listening */
 483         if (!s->d1->listen)
 484                 s->d1->handshake_read_seq++;
 485
 486         s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 487         return s->init_num;
 488
 489 f_err:
 490         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 491         *ok = 0;
 492         return -1;
 493         }
 494
 495
 496 static int dtls1_preprocess_fragment(SSL *s,struct hm_header_st *msg_hdr,int max)
 497         {
 498         size_t frag_off,frag_len,msg_len;
 499
 500         msg_len  = msg_hdr->msg_len;
 501         frag_off = msg_hdr->frag_off;
 502         frag_len = msg_hdr->frag_len;
 503
 504         /* sanity checking */
 505         if ( (frag_off+frag_len) > msg_len)
 506                 {
 507                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 508                 return SSL_AD_ILLEGAL_PARAMETER;
 509                 }
 510
 511         if ( (frag_off+frag_len) > (unsigned long)max)
 512                 {
 513                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 514                 return SSL_AD_ILLEGAL_PARAMETER;
 515                 }
 516
 517         if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */
 518                 {
 519                 /* msg_len is limited to 2^24, but is effectively checked
 520                  * against max above */
 521                 if (!BUF_MEM_grow_clean(s->init_buf,msg_len+DTLS1_HM_HEADER_LENGTH))
 522                         {
 523                         SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,ERR_R_BUF_LIB);
 524                         return SSL_AD_INTERNAL_ERROR;
 525                         }
 526
 527                 s->s3->tmp.message_size  = msg_len;
 528                 s->d1->r_msg_hdr.msg_len = msg_len;
 529                 s->s3->tmp.message_type  = msg_hdr->type;
 530                 s->d1->r_msg_hdr.type    = msg_hdr->type;
 531                 s->d1->r_msg_hdr.seq     = msg_hdr->seq;
 532                 }
 533         else if (msg_len != s->d1->r_msg_hdr.msg_len)
 534                 {
 535                 /* They must be playing with us! BTW, failure to enforce
 536                  * upper limit would open possibility for buffer overrun. */
 537                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 538                 return SSL_AD_ILLEGAL_PARAMETER;
 539                 }
 540
 541         return 0; /* no error */
 542         }
 543
 544
 545 static int
 546 dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok)
 547         {
 548         /* (0) check whether the desired fragment is available
 549          * if so:
 550          * (1) copy over the fragment to s->init_buf->data[]
 551          * (2) update s->init_num
 552          */
 553         pitem *item;
 554         hm_fragment *frag;
 555         int al;
 556
 557         *ok = 0;
 558         item = pqueue_peek(s->d1->buffered_messages);
 559         if ( item == NULL)
 560                 return 0;
 561
 562         frag = (hm_fragment *)item->data;
 563
 564         /* Don't return if reassembly still in progress */
 565         if (frag->reassembly != NULL)
 566                 return 0;
 567
 568         if ( s->d1->handshake_read_seq == frag->msg_header.seq)
 569                 {
 570                 unsigned long frag_len = frag->msg_header.frag_len;
 571                 pqueue_pop(s->d1->buffered_messages);
 572
 573                 al=dtls1_preprocess_fragment(s,&frag->msg_header,max);
 574
 575                 if (al==0) /* no alert */
 576                         {
 577                         unsigned char *p = (unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 578                         memcpy(&p[frag->msg_header.frag_off],
 579                                 frag->fragment,frag->msg_header.frag_len);
 580                         }
 581
 582                 dtls1_hm_fragment_free(frag);
 583                 pitem_free(item);
 584
 585                 if (al==0)
 586                         {
 587                         *ok = 1;
 588                         return frag_len;
 589                         }
 590
 591                 ssl3_send_alert(s,SSL3_AL_FATAL,al);
 592                 s->init_num = 0;
 593                 *ok = 0;
 594                 return -1;
 595                 }
 596         else
 597                 return 0;
 598         }
 599
 600 /* dtls1_max_handshake_message_len returns the maximum number of bytes
 601  * permitted in a DTLS handshake message for |s|. The minimum is 16KB, but may
 602  * be greater if the maximum certificate list size requires it. */
 603 static unsigned long dtls1_max_handshake_message_len(const SSL *s)
 604         {
 605         unsigned long max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
 606         if (max_len < (unsigned long)s->max_cert_list)
 607                 return s->max_cert_list;
 608         return max_len;
 609         }
 610
 611 static int
 612 dtls1_reassemble_fragment(SSL *s, const struct hm_header_st* msg_hdr, int *ok)
 613         {
 614         hm_fragment *frag = NULL;
 615         pitem *item = NULL;
 616         int i = -1, is_complete;
 617         unsigned char seq64be[8];
 618         unsigned long frag_len = msg_hdr->frag_len;
 619
 620         if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len ||
 621             msg_hdr->msg_len > dtls1_max_handshake_message_len(s))
 622                 goto err;
 623
 624         if (frag_len == 0)
 625                 return DTLS1_HM_FRAGMENT_RETRY;
 626
 627         /* Try to find item in queue */
 628         memset(seq64be,0,sizeof(seq64be));
 629         seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
 630         seq64be[7] = (unsigned char) msg_hdr->seq;
 631         item = pqueue_find(s->d1->buffered_messages, seq64be);
 632
 633         if (item == NULL)
 634                 {
 635                 frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
 636                 if ( frag == NULL)
 637                         goto err;
 638                 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 639                 frag->msg_header.frag_len = frag->msg_header.msg_len;
 640                 frag->msg_header.frag_off = 0;
 641                 }
 642         else
 643                 {
 644                 frag = (hm_fragment*) item->data;
 645                 if (frag->msg_header.msg_len != msg_hdr->msg_len)
 646                         {
 647                         item = NULL;
 648                         frag = NULL;
 649                         goto err;
 650                         }
 651                 }
 652
 653
 654         /* If message is already reassembled, this must be a
 655          * retransmit and can be dropped. In this case item != NULL and so frag
 656          * does not need to be freed.
 657          */
 658         if (frag->reassembly == NULL)
 659                 {
 660                 unsigned char devnull [256];
 661
 662                 while (frag_len)
 663                         {
 664                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 665                                 devnull,
 666                                 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
 667                         if (i<=0) goto err;
 668                         frag_len -= i;
 669                         }
 670                 return DTLS1_HM_FRAGMENT_RETRY;
 671                 }
 672
 673         /* read the body of the fragment (header has already been read */
 674         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 675                 frag->fragment + msg_hdr->frag_off,frag_len,0);
 676         if ((unsigned long)i!=frag_len)
 677                 i=-1;
 678         if (i<=0)
 679                 goto err;
 680
 681         RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
 682                             (long)(msg_hdr->frag_off + frag_len));
 683
 684         RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
 685                                    is_complete);
 686
 687         if (is_complete)
 688                 {
 689                 OPENSSL_free(frag->reassembly);
 690                 frag->reassembly = NULL;
 691                 }
 692
 693         if (item == NULL)
 694                 {
 695                 item = pitem_new(seq64be, frag);
 696                 if (item == NULL)
 697                         {
 698                         i = -1;
 699                         goto err;
 700                         }
 701
 702                 item = pqueue_insert(s->d1->buffered_messages, item);
 703                 /* pqueue_insert fails iff a duplicate item is inserted.
 704                  * However, |item| cannot be a duplicate. If it were,
 705                  * |pqueue_find|, above, would have returned it and control
 706                  * would never have reached this branch. */
 707                 OPENSSL_assert(item != NULL);
 708                 }
 709
 710         return DTLS1_HM_FRAGMENT_RETRY;
 711
 712 err:
 713         if (frag != NULL && item == NULL) dtls1_hm_fragment_free(frag);
 714         *ok = 0;
 715         return i;
 716         }
 717
 718
 719 static int
 720 dtls1_process_out_of_seq_message(SSL *s, const struct hm_header_st* msg_hdr, int *ok)
 721 {
 722         int i=-1;
 723         hm_fragment *frag = NULL;
 724         pitem *item = NULL;
 725         unsigned char seq64be[8];
 726         unsigned long frag_len = msg_hdr->frag_len;
 727
 728         if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
 729                 goto err;
 730
 731         /* Try to find item in queue, to prevent duplicate entries */
 732         memset(seq64be,0,sizeof(seq64be));
 733         seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
 734         seq64be[7] = (unsigned char) msg_hdr->seq;
 735         item = pqueue_find(s->d1->buffered_messages, seq64be);
 736
 737         /* If we already have an entry and this one is a fragment,
 738          * don't discard it and rather try to reassemble it.
 739          */
 740         if (item != NULL && frag_len != msg_hdr->msg_len)
 741                 item = NULL;
 742
 743         /* Discard the message if sequence number was already there, is
 744          * too far in the future, already in the queue or if we received
 745          * a FINISHED before the SERVER_HELLO, which then must be a stale
 746          * retransmit.
 747          */
 748         if (msg_hdr->seq <= s->d1->handshake_read_seq ||
 749                 msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
 750                 (s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED))
 751                 {
 752                 unsigned char devnull [256];
 753
 754                 while (frag_len)
 755                         {
 756                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 757                                 devnull,
 758                                 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
 759                         if (i<=0) goto err;
 760                         frag_len -= i;
 761                         }
 762                 }
 763         else
 764                 {
 765                 if (frag_len != msg_hdr->msg_len)
 766                         return dtls1_reassemble_fragment(s, msg_hdr, ok);
 767
 768                 if (frag_len > dtls1_max_handshake_message_len(s))
 769                         goto err;
 770
 771                 frag = dtls1_hm_fragment_new(frag_len, 0);
 772                 if ( frag == NULL)
 773                         goto err;
 774
 775                 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 776
 777                 if (frag_len)
 778                         {
 779                         /* read the body of the fragment (header has already been read */
 780                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 781                                 frag->fragment,frag_len,0);
 782                         if ((unsigned long)i!=frag_len)
 783                                 i = -1;
 784                         if (i<=0)
 785                                 goto err;
 786                         }
 787
 788                 item = pitem_new(seq64be, frag);
 789                 if ( item == NULL)
 790                         goto err;
 791
 792                 item = pqueue_insert(s->d1->buffered_messages, item);
 793                 /* pqueue_insert fails iff a duplicate item is inserted.
 794                  * However, |item| cannot be a duplicate. If it were,
 795                  * |pqueue_find|, above, would have returned it. Then, either
 796                  * |frag_len| != |msg_hdr->msg_len| in which case |item| is set
 797                  * to NULL and it will have been processed with
 798                  * |dtls1_reassemble_fragment|, above, or the record will have
 799                  * been discarded. */
 800                 OPENSSL_assert(item != NULL);
 801                 }
 802
 803         return DTLS1_HM_FRAGMENT_RETRY;
 804
 805 err:
 806         if (frag != NULL && item == NULL) dtls1_hm_fragment_free(frag);
 807         *ok = 0;
 808         return i;
 809         }
 810
 811
 812 static long
 813 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
 814         {
 815         unsigned char wire[DTLS1_HM_HEADER_LENGTH];
 816         unsigned long len, frag_off, frag_len;
 817         int i,al;
 818         struct hm_header_st msg_hdr;
 819
 820         redo:
 821         /* see if we have the required fragment already */
 822         if ((frag_len = dtls1_retrieve_buffered_fragment(s,max,ok)) || *ok)
 823                 {
 824                 if (*ok)        s->init_num = frag_len;
 825                 return frag_len;
 826                 }
 827
 828         /* read handshake message header */
 829         i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,wire,
 830                 DTLS1_HM_HEADER_LENGTH, 0);
 831         if (i <= 0)     /* nbio, or an error */
 832                 {
 833                 s->rwstate=SSL_READING;
 834                 *ok = 0;
 835                 return i;
 836                 }
 837         /* Handshake fails if message header is incomplete */
 838         if (i != DTLS1_HM_HEADER_LENGTH)
 839                 {
 840                 al=SSL_AD_UNEXPECTED_MESSAGE;
 841                 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 842                 goto f_err;
 843                 }
 844
 845         /* parse the message fragment header */
 846         dtls1_get_message_header(wire, &msg_hdr);
 847
 848         /*
 849          * if this is a future (or stale) message it gets buffered
 850          * (or dropped)--no further processing at this time
 851          * While listening, we accept seq 1 (ClientHello with cookie)
 852          * although we're still expecting seq 0 (ClientHello)
 853          */
 854         if (msg_hdr.seq != s->d1->handshake_read_seq && !(s->d1->listen && msg_hdr.seq == 1))
 855                 return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
 856
 857         len = msg_hdr.msg_len;
 858         frag_off = msg_hdr.frag_off;
 859         frag_len = msg_hdr.frag_len;
 860
 861         if (frag_len && frag_len < len)
 862                 return dtls1_reassemble_fragment(s, &msg_hdr, ok);
 863
 864         if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
 865                 wire[0] == SSL3_MT_HELLO_REQUEST)
 866                 {
 867                 /* The server may always send 'Hello Request' messages --
 868                  * we are doing a handshake anyway now, so ignore them
 869                  * if their format is correct. Does not count for
 870                  * 'Finished' MAC. */
 871                 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0)
 872                         {
 873                         if (s->msg_callback)
 874                                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 875                                         wire, DTLS1_HM_HEADER_LENGTH, s,
 876                                         s->msg_callback_arg);
 877
 878                         s->init_num = 0;
 879                         goto redo;
 880                         }
 881                 else /* Incorrectly formated Hello request */
 882                         {
 883                         al=SSL_AD_UNEXPECTED_MESSAGE;
 884                         SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 885                         goto f_err;
 886                         }
 887                 }
 888
 889         if ((al=dtls1_preprocess_fragment(s,&msg_hdr,max)))
 890                 goto f_err;
 891
 892         /* XDTLS:  ressurect this when restart is in place */
 893         s->state=stn;
 894
 895         if ( frag_len > 0)
 896                 {
 897                 unsigned char *p=(unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 898
 899                 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 900                         &p[frag_off],frag_len,0);
 901                 /* XDTLS:  fix this--message fragments cannot span multiple packets */
 902                 if (i <= 0)
 903                         {
 904                         s->rwstate=SSL_READING;
 905                         *ok = 0;
 906                         return i;
 907                         }
 908                 }
 909         else
 910                 i = 0;
 911
 912         /* XDTLS:  an incorrectly formatted fragment should cause the
 913          * handshake to fail */
 914         if (i != (int)frag_len)
 915                 {
 916                 al=SSL3_AD_ILLEGAL_PARAMETER;
 917                 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL3_AD_ILLEGAL_PARAMETER);
 918                 goto f_err;
 919                 }
 920
 921         *ok = 1;
 922
 923         /* Note that s->init_num is *not* used as current offset in
 924          * s->init_buf->data, but as a counter summing up fragments'
 925          * lengths: as soon as they sum up to handshake packet
 926          * length, we assume we have got all the fragments. */
 927         s->init_num = frag_len;
 928         return frag_len;
 929
 930 f_err:
 931         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 932         s->init_num = 0;
 933
 934         *ok=0;
 935         return(-1);
 936         }
 937
 938 /* for these 2 messages, we need to
 939  * ssl->enc_read_ctx                    re-init
 940  * ssl->s3->read_sequence               zero
 941  * ssl->s3->read_mac_secret             re-init
 942  * ssl->session->read_sym_enc           assign
 943  * ssl->session->read_compression       assign
 944  * ssl->session->read_hash              assign
 945  */
 946 int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
 947         {
 948         unsigned char *p;
 949
 950         if (s->state == a)
 951                 {
 952                 p=(unsigned char *)s->init_buf->data;
 953                 *p++=SSL3_MT_CCS;
 954                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
 955                 s->init_num=DTLS1_CCS_HEADER_LENGTH;
 956
 957                 if (s->version == DTLS1_BAD_VER) {
 958                         s->d1->next_handshake_write_seq++;
 959                         s2n(s->d1->handshake_write_seq,p);
 960                         s->init_num+=2;
 961                 }
 962
 963                 s->init_off=0;
 964
 965                 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
 966                         s->d1->handshake_write_seq, 0, 0);
 967
 968                 /* buffer the message to handle re-xmits */
 969                 dtls1_buffer_message(s, 1);
 970
 971                 s->state=b;
 972                 }
 973
 974         /* SSL3_ST_CW_CHANGE_B */
 975         return(dtls1_do_write(s,SSL3_RT_CHANGE_CIPHER_SPEC));
 976         }
 977
 978 int dtls1_read_failed(SSL *s, int code)
 979         {
 980         if ( code > 0)
 981                 {
 982                 fprintf( stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
 983                 return 1;
 984                 }
 985
 986         if (!dtls1_is_timer_expired(s))
 987                 {
 988                 /* not a timeout, none of our business,
 989                    let higher layers handle this.  in fact it's probably an error */
 990                 return code;
 991                 }
 992
 993 #ifndef OPENSSL_NO_HEARTBEATS
 994         if (!SSL_in_init(s) && !s->tlsext_hb_pending)  /* done, no need to send a retransmit */
 995 #else
 996         if (!SSL_in_init(s))  /* done, no need to send a retransmit */
 997 #endif
 998                 {
 999                 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
1000                 return code;
1001                 }
1002
1003 #if 0 /* for now, each alert contains only one record number */
1004         item = pqueue_peek(state->rcvd_records);
1005         if ( item )
1006                 {
1007                 /* send an alert immediately for all the missing records */
1008                 }
1009         else
1010 #endif
1011
1012 #if 0  /* no more alert sending, just retransmit the last set of messages */
1013         if ( state->timeout.read_timeouts >= DTLS1_TMO_READ_COUNT)
1014                 ssl3_send_alert(s,SSL3_AL_WARNING,
1015                         DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
1016 #endif
1017
1018         return dtls1_handle_timeout(s);
1019         }
1020
1021 int
1022 dtls1_get_queue_priority(unsigned short seq, int is_ccs)
1023         {
1024         /* The index of the retransmission queue actually is the message sequence number,
1025          * since the queue only contains messages of a single handshake. However, the
1026          * ChangeCipherSpec has no message sequence number and so using only the sequence
1027          * will result in the CCS and Finished having the same index. To prevent this,
1028          * the sequence number is multiplied by 2. In case of a CCS 1 is subtracted.
1029          * This does not only differ CSS and Finished, it also maintains the order of the
1030          * index (important for priority queues) and fits in the unsigned short variable.
1031          */
1032         return seq * 2 - is_ccs;
1033         }
1034
1035 int
1036 dtls1_retransmit_buffered_messages(SSL *s)
1037         {
1038         pqueue sent = s->d1->sent_messages;
1039         piterator iter;
1040         pitem *item;
1041         hm_fragment *frag;
1042         int found = 0;
1043
1044         iter = pqueue_iterator(sent);
1045
1046         for ( item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter))
1047                 {
1048                 frag = (hm_fragment *)item->data;
1049                         if ( dtls1_retransmit_message(s,
1050                                 (unsigned short)dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs),
1051                                 0, &found) <= 0 && found)
1052                         {
1053                         fprintf(stderr, "dtls1_retransmit_message() failed\n");
1054                         return -1;
1055                         }
1056                 }
1057
1058         return 1;
1059         }
1060
1061 int
1062 dtls1_buffer_message(SSL *s, int is_ccs)
1063         {
1064         pitem *item;
1065         hm_fragment *frag;
1066         unsigned char seq64be[8];
1067
1068         /* this function is called immediately after a message has
1069          * been serialized */
1070         OPENSSL_assert(s->init_off == 0);
1071
1072         frag = dtls1_hm_fragment_new(s->init_num, 0);
1073         if (!frag)
1074                 return 0;
1075
1076         memcpy(frag->fragment, s->init_buf->data, s->init_num);
1077
1078         if ( is_ccs)
1079                 {
1080                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1081                                DTLS1_CCS_HEADER_LENGTH == (unsigned int)s->init_num);
1082                 }
1083         else
1084                 {
1085                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1086                         DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
1087                 }
1088
1089         frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1090         frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1091         frag->msg_header.type = s->d1->w_msg_hdr.type;
1092         frag->msg_header.frag_off = 0;
1093         frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1094         frag->msg_header.is_ccs = is_ccs;
1095
1096         /* save current state*/
1097         frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
1098         frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
1099         frag->msg_header.saved_retransmit_state.compress = s->compress;
1100         frag->msg_header.saved_retransmit_state.session = s->session;
1101         frag->msg_header.saved_retransmit_state.epoch = s->d1->w_epoch;
1102
1103         memset(seq64be,0,sizeof(seq64be));
1104         seq64be[6] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1105                                                                                                                   frag->msg_header.is_ccs)>>8);
1106         seq64be[7] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1107                                                                                                                   frag->msg_header.is_ccs));
1108
1109         item = pitem_new(seq64be, frag);
1110         if ( item == NULL)
1111                 {
1112                 dtls1_hm_fragment_free(frag);
1113                 return 0;
1114                 }
1115
1116 #if 0
1117         fprintf( stderr, "buffered messge: \ttype = %xx\n", msg_buf->type);
1118         fprintf( stderr, "\t\t\t\t\tlen = %d\n", msg_buf->len);
1119         fprintf( stderr, "\t\t\t\t\tseq_num = %d\n", msg_buf->seq_num);
1120 #endif
1121
1122         pqueue_insert(s->d1->sent_messages, item);
1123         return 1;
1124         }
1125
1126 int
1127 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
1128         int *found)
1129         {
1130         int ret;
1131         /* XDTLS: for now assuming that read/writes are blocking */
1132         pitem *item;
1133         hm_fragment *frag ;
1134         unsigned long header_length;
1135         unsigned char seq64be[8];
1136         struct dtls1_retransmit_state saved_state;
1137         unsigned char save_write_sequence[8];
1138
1139         /*
1140           OPENSSL_assert(s->init_num == 0);
1141           OPENSSL_assert(s->init_off == 0);
1142          */
1143
1144         /* XDTLS:  the requested message ought to be found, otherwise error */
1145         memset(seq64be,0,sizeof(seq64be));
1146         seq64be[6] = (unsigned char)(seq>>8);
1147         seq64be[7] = (unsigned char)seq;
1148
1149         item = pqueue_find(s->d1->sent_messages, seq64be);
1150         if ( item == NULL)
1151                 {
1152                 fprintf(stderr, "retransmit:  message %d non-existant\n", seq);
1153                 *found = 0;
1154                 return 0;
1155                 }
1156
1157         *found = 1;
1158         frag = (hm_fragment *)item->data;
1159
1160         if ( frag->msg_header.is_ccs)
1161                 header_length = DTLS1_CCS_HEADER_LENGTH;
1162         else
1163                 header_length = DTLS1_HM_HEADER_LENGTH;
1164
1165         memcpy(s->init_buf->data, frag->fragment,
1166                 frag->msg_header.msg_len + header_length);
1167                 s->init_num = frag->msg_header.msg_len + header_length;
1168
1169         dtls1_set_message_header_int(s, frag->msg_header.type,
1170                 frag->msg_header.msg_len, frag->msg_header.seq, 0,
1171                 frag->msg_header.frag_len);
1172
1173         /* save current state */
1174         saved_state.enc_write_ctx = s->enc_write_ctx;
1175         saved_state.write_hash = s->write_hash;
1176         saved_state.compress = s->compress;
1177         saved_state.session = s->session;
1178         saved_state.epoch = s->d1->w_epoch;
1179         saved_state.epoch = s->d1->w_epoch;
1180
1181         s->d1->retransmitting = 1;
1182
1183         /* restore state in which the message was originally sent */
1184         s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
1185         s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
1186         s->compress = frag->msg_header.saved_retransmit_state.compress;
1187         s->session = frag->msg_header.saved_retransmit_state.session;
1188         s->d1->w_epoch = frag->msg_header.saved_retransmit_state.epoch;
1189
1190         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1191         {
1192                 memcpy(save_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1193                 memcpy(s->s3->write_sequence, s->d1->last_write_sequence, sizeof(s->s3->write_sequence));
1194         }
1195
1196         ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1197                                                  SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1198
1199         /* restore current state */
1200         s->enc_write_ctx = saved_state.enc_write_ctx;
1201         s->write_hash = saved_state.write_hash;
1202         s->compress = saved_state.compress;
1203         s->session = saved_state.session;
1204         s->d1->w_epoch = saved_state.epoch;
1205
1206         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1207         {
1208                 memcpy(s->d1->last_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1209                 memcpy(s->s3->write_sequence, save_write_sequence, sizeof(s->s3->write_sequence));
1210         }
1211
1212         s->d1->retransmitting = 0;
1213
1214         (void)BIO_flush(SSL_get_wbio(s));
1215         return ret;
1216         }
1217
1218 /* call this function when the buffered messages are no longer needed */
1219 void
1220 dtls1_clear_record_buffer(SSL *s)
1221         {
1222         pitem *item;
1223
1224         for(item = pqueue_pop(s->d1->sent_messages);
1225                 item != NULL; item = pqueue_pop(s->d1->sent_messages))
1226                 {
1227                 dtls1_hm_fragment_free((hm_fragment *)item->data);
1228                 pitem_free(item);
1229                 }
1230         }
1231
1232
1233 unsigned char *
1234 dtls1_set_message_header(SSL *s, unsigned char *p, unsigned char mt,
1235                         unsigned long len, unsigned long frag_off, unsigned long frag_len)
1236         {
1237         /* Don't change sequence numbers while listening */
1238         if (frag_off == 0 && !s->d1->listen)
1239                 {
1240                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1241                 s->d1->next_handshake_write_seq++;
1242                 }
1243
1244         dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1245                 frag_off, frag_len);
1246
1247         return p += DTLS1_HM_HEADER_LENGTH;
1248         }
1249
1250
1251 /* don't actually do the writing, wait till the MTU has been retrieved */
1252 static void
1253 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1254                             unsigned long len, unsigned short seq_num, unsigned long frag_off,
1255                             unsigned long frag_len)
1256         {
1257         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1258
1259         msg_hdr->type = mt;
1260         msg_hdr->msg_len = len;
1261         msg_hdr->seq = seq_num;
1262         msg_hdr->frag_off = frag_off;
1263         msg_hdr->frag_len = frag_len;
1264         }
1265
1266 static void
1267 dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1268                         unsigned long frag_len)
1269         {
1270         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1271
1272         msg_hdr->frag_off = frag_off;
1273         msg_hdr->frag_len = frag_len;
1274         }
1275
1276 static unsigned char *
1277 dtls1_write_message_header(SSL *s, unsigned char *p)
1278         {
1279         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1280
1281         *p++ = msg_hdr->type;
1282         l2n3(msg_hdr->msg_len, p);
1283
1284         s2n(msg_hdr->seq, p);
1285         l2n3(msg_hdr->frag_off, p);
1286         l2n3(msg_hdr->frag_len, p);
1287
1288         return p;
1289         }
1290
1291 unsigned int
1292 dtls1_min_mtu(void)
1293         {
1294         return (g_probable_mtu[(sizeof(g_probable_mtu) /
1295                 sizeof(g_probable_mtu[0])) - 1]);
1296         }
1297
1298 static unsigned int
1299 dtls1_guess_mtu(unsigned int curr_mtu)
1300         {
1301         unsigned int i;
1302
1303         if ( curr_mtu == 0 )
1304                 return g_probable_mtu[0] ;
1305
1306         for ( i = 0; i < sizeof(g_probable_mtu)/sizeof(g_probable_mtu[0]); i++)
1307                 if ( curr_mtu > g_probable_mtu[i])
1308                         return g_probable_mtu[i];
1309
1310         return curr_mtu;
1311         }
1312
1313 void
1314 dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1315         {
1316         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
1317         msg_hdr->type = *(data++);
1318         n2l3(data, msg_hdr->msg_len);
1319
1320         n2s(data, msg_hdr->seq);
1321         n2l3(data, msg_hdr->frag_off);
1322         n2l3(data, msg_hdr->frag_len);
1323         }
1324
1325 void
1326 dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
1327         {
1328         memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
1329
1330         ccs_hdr->type = *(data++);
1331         }
1332
1333 int dtls1_shutdown(SSL *s)
1334         {
1335         int ret;
1336 #ifndef OPENSSL_NO_SCTP
1337         if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
1338             !(s->shutdown & SSL_SENT_SHUTDOWN))
1339                 {
1340                 ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
1341                 if (ret < 0) return -1;
1342
1343                 if (ret == 0)
1344                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1, NULL);
1345                 }
1346 #endif
1347         ret = ssl3_shutdown(s);
1348 #ifndef OPENSSL_NO_SCTP
1349         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
1350 #endif
1351         return ret;
1352         }
1353
1354 #ifndef OPENSSL_NO_HEARTBEATS
1355 int
1356 dtls1_process_heartbeat(SSL *s)
1357         {
1358         unsigned char *p = &s->s3->rrec.data[0], *pl;
1359         unsigned short hbtype;
1360         unsigned int payload;
1361         unsigned int padding = 16; /* Use minimum padding */
1362
1363         if (s->msg_callback)
1364                 s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
1365                         &s->s3->rrec.data[0], s->s3->rrec.length,
1366                         s, s->msg_callback_arg);
1367
1368         /* Read type and payload length first */
1369         if (1 + 2 + 16 > s->s3->rrec.length)
1370                 return 0; /* silently discard */
1371         if (s->s3->rrec.length > SSL3_RT_MAX_PLAIN_LENGTH)
1372                 return 0; /* silently discard per RFC 6520 sec. 4 */
1373
1374         hbtype = *p++;
1375         n2s(p, payload);
1376         if (1 + 2 + payload + 16 > s->s3->rrec.length)
1377                 return 0; /* silently discard per RFC 6520 sec. 4 */
1378         pl = p;
1379
1380         if (hbtype == TLS1_HB_REQUEST)
1381                 {
1382                 unsigned char *buffer, *bp;
1383                 unsigned int write_length = 1 /* heartbeat type */ +
1384                                             2 /* heartbeat length */ +
1385                                             payload + padding;
1386                 int r;
1387
1388                 if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
1389                         return 0;
1390
1391                 /* Allocate memory for the response, size is 1 byte
1392                  * message type, plus 2 bytes payload length, plus
1393                  * payload, plus padding
1394                  */
1395                 buffer = OPENSSL_malloc(write_length);
1396                 bp = buffer;
1397
1398                 /* Enter response type, length and copy payload */
1399                 *bp++ = TLS1_HB_RESPONSE;
1400                 s2n(payload, bp);
1401                 memcpy(bp, pl, payload);
1402                 bp += payload;
1403                 /* Random padding */
1404                 RAND_pseudo_bytes(bp, padding);
1405
1406                 r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
1407
1408                 if (r >= 0 && s->msg_callback)
1409                         s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1410                                 buffer, write_length,
1411                                 s, s->msg_callback_arg);
1412
1413                 OPENSSL_free(buffer);
1414
1415                 if (r < 0)
1416                         return r;
1417                 }
1418         else if (hbtype == TLS1_HB_RESPONSE)
1419                 {
1420                 unsigned int seq;
1421
1422                 /* We only send sequence numbers (2 bytes unsigned int),
1423                  * and 16 random bytes, so we just try to read the
1424                  * sequence number */
1425                 n2s(pl, seq);
1426
1427                 if (payload == 18 && seq == s->tlsext_hb_seq)
1428                         {
1429                         dtls1_stop_timer(s);
1430                         s->tlsext_hb_seq++;
1431                         s->tlsext_hb_pending = 0;
1432                         }
1433                 }
1434
1435         return 0;
1436         }
1437
1438 int
1439 dtls1_heartbeat(SSL *s)
1440         {
1441         unsigned char *buf, *p;
1442         int ret;
1443         unsigned int payload = 18; /* Sequence number + random bytes */
1444         unsigned int padding = 16; /* Use minimum padding */
1445
1446         /* Only send if peer supports and accepts HB requests... */
1447         if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
1448             s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS)
1449                 {
1450                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
1451                 return -1;
1452                 }
1453
1454         /* ...and there is none in flight yet... */
1455         if (s->tlsext_hb_pending)
1456                 {
1457                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PENDING);
1458                 return -1;
1459                 }
1460
1461         /* ...and no handshake in progress. */
1462         if (SSL_in_init(s) || s->in_handshake)
1463                 {
1464                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_UNEXPECTED_MESSAGE);
1465                 return -1;
1466                 }
1467
1468         /* Check if padding is too long, payload and padding
1469          * must not exceed 2^14 - 3 = 16381 bytes in total.
1470          */
1471         OPENSSL_assert(payload + padding <= 16381);
1472
1473         /* Create HeartBeat message, we just use a sequence number
1474          * as payload to distuingish different messages and add
1475          * some random stuff.
1476          *  - Message Type, 1 byte
1477          *  - Payload Length, 2 bytes (unsigned int)
1478          *  - Payload, the sequence number (2 bytes uint)
1479          *  - Payload, random bytes (16 bytes uint)
1480          *  - Padding
1481          */
1482         buf = OPENSSL_malloc(1 + 2 + payload + padding);
1483         p = buf;
1484         /* Message Type */
1485         *p++ = TLS1_HB_REQUEST;
1486         /* Payload length (18 bytes here) */
1487         s2n(payload, p);
1488         /* Sequence number */
1489         s2n(s->tlsext_hb_seq, p);
1490         /* 16 random bytes */
1491         RAND_pseudo_bytes(p, 16);
1492         p += 16;
1493         /* Random padding */
1494         RAND_pseudo_bytes(p, padding);
1495
1496         ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
1497         if (ret >= 0)
1498                 {
1499                 if (s->msg_callback)
1500                         s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1501                                 buf, 3 + payload + padding,
1502                                 s, s->msg_callback_arg);
1503
1504                 dtls1_start_timer(s);
1505                 s->tlsext_hb_pending = 1;
1506                 }
1507
1508         OPENSSL_free(buf);
1509
1510         return ret;
1511         }
1512 #endif