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, 512, 256};
 160
 161 static void dtls1_guess_mtu(SSL *s);
 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 static void dtls1_query_mtu(SSL *s)
 228 {
 229         if(s->d1->link_mtu)
 230                 {
 231                 s->d1->mtu = s->d1->link_mtu-BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
 232                 s->d1->link_mtu = 0;
 233                 }
 234
 235         /* AHA!  Figure out the MTU, and stick to the right size */
 236         if (s->d1->mtu < dtls1_min_mtu(s) && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
 237                 {
 238                 s->d1->mtu =
 239                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
 240
 241                 /* I've seen the kernel return bogus numbers when it doesn't know
 242                  * (initial write), so just make sure we have a reasonable number */
 243                 if (s->d1->mtu < dtls1_min_mtu(s))
 244                         {
 245                         s->d1->mtu = 0;
 246                         dtls1_guess_mtu(s);
 247                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
 248                                 s->d1->mtu, NULL);
 249                         }
 250                 }
 251 }
 252
 253 /* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
 254 int dtls1_do_write(SSL *s, int type)
 255         {
 256         int ret;
 257         int curr_mtu;
 258         unsigned int len, frag_off, mac_size, blocksize;
 259
 260         dtls1_query_mtu(s);
 261 #if 0
 262         mtu = s->d1->mtu;
 263
 264         fprintf(stderr, "using MTU = %d\n", mtu);
 265
 266         mtu -= (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 267
 268         curr_mtu = mtu - BIO_wpending(SSL_get_wbio(s));
 269
 270         if ( curr_mtu > 0)
 271                 mtu = curr_mtu;
 272         else if ( ( ret = BIO_flush(SSL_get_wbio(s))) <= 0)
 273                 return ret;
 274
 275         if ( BIO_wpending(SSL_get_wbio(s)) + s->init_num >= mtu)
 276                 {
 277                 ret = BIO_flush(SSL_get_wbio(s));
 278                 if ( ret <= 0)
 279                         return ret;
 280                 mtu = s->d1->mtu - (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 281                 }
 282 #endif
 283
 284         OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu(s));  /* should have something reasonable now */
 285
 286         if ( s->init_off == 0  && type == SSL3_RT_HANDSHAKE)
 287                 OPENSSL_assert(s->init_num ==
 288                         (int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH);
 289
 290         if (s->write_hash)
 291                 {
 292                 if (s->enc_write_ctx && EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_GCM_MODE)
 293                         mac_size = 0;
 294                 else
 295                         mac_size = EVP_MD_CTX_size(s->write_hash);
 296                 }
 297         else
 298                 mac_size = 0;
 299
 300         if (s->enc_write_ctx &&
 301                 (EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_CBC_MODE))
 302                 blocksize = 2 * EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
 303         else
 304                 blocksize = 0;
 305
 306         frag_off = 0;
 307         while( s->init_num)
 308                 {
 309                 curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) -
 310                         DTLS1_RT_HEADER_LENGTH - mac_size - blocksize;
 311
 312                 if ( curr_mtu <= DTLS1_HM_HEADER_LENGTH)
 313                         {
 314                         /* grr.. we could get an error if MTU picked was wrong */
 315                         ret = BIO_flush(SSL_get_wbio(s));
 316                         if ( ret <= 0)
 317                                 return ret;
 318                         curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH -
 319                                 mac_size - blocksize;
 320                         }
 321
 322                 if ( s->init_num > curr_mtu)
 323                         len = curr_mtu;
 324                 else
 325                         len = s->init_num;
 326
 327
 328                 /* XDTLS: this function is too long.  split out the CCS part */
 329                 if ( type == SSL3_RT_HANDSHAKE)
 330                         {
 331                         if ( s->init_off != 0)
 332                                 {
 333                                 OPENSSL_assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
 334                                 s->init_off -= DTLS1_HM_HEADER_LENGTH;
 335                                 s->init_num += DTLS1_HM_HEADER_LENGTH;
 336
 337                                 if ( s->init_num > curr_mtu)
 338                                         len = curr_mtu;
 339                                 else
 340                                         len = s->init_num;
 341                                 }
 342
 343                         if ( len < DTLS1_HM_HEADER_LENGTH )
 344                                 {
 345                                 /*
 346                                  * len is so small that we really can't do anything sensible
 347                                  * so fail
 348                                  */
 349                                 return -1;
 350                                 }
 351                         dtls1_fix_message_header(s, frag_off,
 352                                 len - DTLS1_HM_HEADER_LENGTH);
 353
 354                         dtls1_write_message_header(s, (unsigned char *)&s->init_buf->data[s->init_off]);
 355                         }
 356
 357                 ret=dtls1_write_bytes(s,type,&s->init_buf->data[s->init_off],
 358                         len);
 359                 if (ret < 0)
 360                         {
 361                         /* might need to update MTU here, but we don't know
 362                          * which previous packet caused the failure -- so can't
 363                          * really retransmit anything.  continue as if everything
 364                          * is fine and wait for an alert to handle the
 365                          * retransmit
 366                          */
 367                         if ( BIO_ctrl(SSL_get_wbio(s),
 368                                 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0 )
 369                                 {
 370                                 if(!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
 371                                         dtls1_query_mtu(s);
 372                                 else
 373                                         return -1;
 374                                 }
 375                         else
 376                                 {
 377                                 return(-1);
 378                                 }
 379                         }
 380                 else
 381                         {
 382
 383                         /* bad if this assert fails, only part of the handshake
 384                          * message got sent.  but why would this happen? */
 385                         OPENSSL_assert(len == (unsigned int)ret);
 386
 387                         if (type == SSL3_RT_HANDSHAKE && ! s->d1->retransmitting)
 388                                 {
 389                                 /* should not be done for 'Hello Request's, but in that case
 390                                  * we'll ignore the result anyway */
 391                                 unsigned char *p = (unsigned char *)&s->init_buf->data[s->init_off];
 392                                 const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
 393                                 int xlen;
 394
 395                                 if (frag_off == 0 && s->version != DTLS1_BAD_VER)
 396                                         {
 397                                         /* reconstruct message header is if it
 398                                          * is being sent in single fragment */
 399                                         *p++ = msg_hdr->type;
 400                                         l2n3(msg_hdr->msg_len,p);
 401                                         s2n (msg_hdr->seq,p);
 402                                         l2n3(0,p);
 403                                         l2n3(msg_hdr->msg_len,p);
 404                                         p  -= DTLS1_HM_HEADER_LENGTH;
 405                                         xlen = ret;
 406                                         }
 407                                 else
 408                                         {
 409                                         p  += DTLS1_HM_HEADER_LENGTH;
 410                                         xlen = ret - DTLS1_HM_HEADER_LENGTH;
 411                                         }
 412
 413                                 ssl3_finish_mac(s, p, xlen);
 414                                 }
 415
 416                         if (ret == s->init_num)
 417                                 {
 418                                 if (s->msg_callback)
 419                                         s->msg_callback(1, s->version, type, s->init_buf->data,
 420                                                 (size_t)(s->init_off + s->init_num), s,
 421                                                 s->msg_callback_arg);
 422
 423                                 s->init_off = 0;  /* done writing this message */
 424                                 s->init_num = 0;
 425
 426                                 return(1);
 427                                 }
 428                         s->init_off+=ret;
 429                         s->init_num-=ret;
 430                         frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
 431                         }
 432                 }
 433         return(0);
 434         }
 435
 436
 437 /* Obtain handshake message of message type 'mt' (any if mt == -1),
 438  * maximum acceptable body length 'max'.
 439  * Read an entire handshake message.  Handshake messages arrive in
 440  * fragments.
 441  */
 442 long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
 443         {
 444         int i, al;
 445         struct hm_header_st *msg_hdr;
 446         unsigned char *p;
 447         unsigned long msg_len;
 448
 449         /* s3->tmp is used to store messages that are unexpected, caused
 450          * by the absence of an optional handshake message */
 451         if (s->s3->tmp.reuse_message)
 452                 {
 453                 s->s3->tmp.reuse_message=0;
 454                 if ((mt >= 0) && (s->s3->tmp.message_type != mt))
 455                         {
 456                         al=SSL_AD_UNEXPECTED_MESSAGE;
 457                         SSLerr(SSL_F_DTLS1_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
 458                         goto f_err;
 459                         }
 460                 *ok=1;
 461                 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 462                 s->init_num = (int)s->s3->tmp.message_size;
 463                 return s->init_num;
 464                 }
 465
 466         msg_hdr = &s->d1->r_msg_hdr;
 467         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 468
 469 again:
 470         i = dtls1_get_message_fragment(s, st1, stn, max, ok);
 471         if ( i == DTLS1_HM_BAD_FRAGMENT ||
 472                 i == DTLS1_HM_FRAGMENT_RETRY)  /* bad fragment received */
 473                 goto again;
 474         else if ( i <= 0 && !*ok)
 475                 return i;
 476
 477         p = (unsigned char *)s->init_buf->data;
 478         msg_len = msg_hdr->msg_len;
 479
 480         /* reconstruct message header */
 481         *(p++) = msg_hdr->type;
 482         l2n3(msg_len,p);
 483         s2n (msg_hdr->seq,p);
 484         l2n3(0,p);
 485         l2n3(msg_len,p);
 486         if (s->version != DTLS1_BAD_VER) {
 487                 p       -= DTLS1_HM_HEADER_LENGTH;
 488                 msg_len += DTLS1_HM_HEADER_LENGTH;
 489         }
 490
 491         ssl3_finish_mac(s, p, msg_len);
 492         if (s->msg_callback)
 493                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 494                         p, msg_len,
 495                         s, s->msg_callback_arg);
 496
 497         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 498
 499         /* Don't change sequence numbers while listening */
 500         if (!s->d1->listen)
 501                 s->d1->handshake_read_seq++;
 502
 503         s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 504         return s->init_num;
 505
 506 f_err:
 507         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 508         *ok = 0;
 509         return -1;
 510         }
 511
 512
 513 static int dtls1_preprocess_fragment(SSL *s,struct hm_header_st *msg_hdr,int max)
 514         {
 515         size_t frag_off,frag_len,msg_len;
 516
 517         msg_len  = msg_hdr->msg_len;
 518         frag_off = msg_hdr->frag_off;
 519         frag_len = msg_hdr->frag_len;
 520
 521         /* sanity checking */
 522         if ( (frag_off+frag_len) > msg_len)
 523                 {
 524                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 525                 return SSL_AD_ILLEGAL_PARAMETER;
 526                 }
 527
 528         if ( (frag_off+frag_len) > (unsigned long)max)
 529                 {
 530                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 531                 return SSL_AD_ILLEGAL_PARAMETER;
 532                 }
 533
 534         if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */
 535                 {
 536                 /* msg_len is limited to 2^24, but is effectively checked
 537                  * against max above */
 538                 if (!BUF_MEM_grow_clean(s->init_buf,msg_len+DTLS1_HM_HEADER_LENGTH))
 539                         {
 540                         SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,ERR_R_BUF_LIB);
 541                         return SSL_AD_INTERNAL_ERROR;
 542                         }
 543
 544                 s->s3->tmp.message_size  = msg_len;
 545                 s->d1->r_msg_hdr.msg_len = msg_len;
 546                 s->s3->tmp.message_type  = msg_hdr->type;
 547                 s->d1->r_msg_hdr.type    = msg_hdr->type;
 548                 s->d1->r_msg_hdr.seq     = msg_hdr->seq;
 549                 }
 550         else if (msg_len != s->d1->r_msg_hdr.msg_len)
 551                 {
 552                 /* They must be playing with us! BTW, failure to enforce
 553                  * upper limit would open possibility for buffer overrun. */
 554                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 555                 return SSL_AD_ILLEGAL_PARAMETER;
 556                 }
 557
 558         return 0; /* no error */
 559         }
 560
 561
 562 static int
 563 dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok)
 564         {
 565         /* (0) check whether the desired fragment is available
 566          * if so:
 567          * (1) copy over the fragment to s->init_buf->data[]
 568          * (2) update s->init_num
 569          */
 570         pitem *item;
 571         hm_fragment *frag;
 572         int al;
 573
 574         *ok = 0;
 575         item = pqueue_peek(s->d1->buffered_messages);
 576         if ( item == NULL)
 577                 return 0;
 578
 579         frag = (hm_fragment *)item->data;
 580
 581         /* Don't return if reassembly still in progress */
 582         if (frag->reassembly != NULL)
 583                 return 0;
 584
 585         if ( s->d1->handshake_read_seq == frag->msg_header.seq)
 586                 {
 587                 unsigned long frag_len = frag->msg_header.frag_len;
 588                 pqueue_pop(s->d1->buffered_messages);
 589
 590                 al=dtls1_preprocess_fragment(s,&frag->msg_header,max);
 591
 592                 if (al==0) /* no alert */
 593                         {
 594                         unsigned char *p = (unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 595                         memcpy(&p[frag->msg_header.frag_off],
 596                                 frag->fragment,frag->msg_header.frag_len);
 597                         }
 598
 599                 dtls1_hm_fragment_free(frag);
 600                 pitem_free(item);
 601
 602                 if (al==0)
 603                         {
 604                         *ok = 1;
 605                         return frag_len;
 606                         }
 607
 608                 ssl3_send_alert(s,SSL3_AL_FATAL,al);
 609                 s->init_num = 0;
 610                 *ok = 0;
 611                 return -1;
 612                 }
 613         else
 614                 return 0;
 615         }
 616
 617 /* dtls1_max_handshake_message_len returns the maximum number of bytes
 618  * permitted in a DTLS handshake message for |s|. The minimum is 16KB, but may
 619  * be greater if the maximum certificate list size requires it. */
 620 static unsigned long dtls1_max_handshake_message_len(const SSL *s)
 621         {
 622         unsigned long max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
 623         if (max_len < (unsigned long)s->max_cert_list)
 624                 return s->max_cert_list;
 625         return max_len;
 626         }
 627
 628 static int
 629 dtls1_reassemble_fragment(SSL *s, const struct hm_header_st* msg_hdr, int *ok)
 630         {
 631         hm_fragment *frag = NULL;
 632         pitem *item = NULL;
 633         int i = -1, is_complete;
 634         unsigned char seq64be[8];
 635         unsigned long frag_len = msg_hdr->frag_len;
 636
 637         if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len ||
 638             msg_hdr->msg_len > dtls1_max_handshake_message_len(s))
 639                 goto err;
 640
 641         if (frag_len == 0)
 642                 return DTLS1_HM_FRAGMENT_RETRY;
 643
 644         /* Try to find item in queue */
 645         memset(seq64be,0,sizeof(seq64be));
 646         seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
 647         seq64be[7] = (unsigned char) msg_hdr->seq;
 648         item = pqueue_find(s->d1->buffered_messages, seq64be);
 649
 650         if (item == NULL)
 651                 {
 652                 frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
 653                 if ( frag == NULL)
 654                         goto err;
 655                 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 656                 frag->msg_header.frag_len = frag->msg_header.msg_len;
 657                 frag->msg_header.frag_off = 0;
 658                 }
 659         else
 660                 {
 661                 frag = (hm_fragment*) item->data;
 662                 if (frag->msg_header.msg_len != msg_hdr->msg_len)
 663                         {
 664                         item = NULL;
 665                         frag = NULL;
 666                         goto err;
 667                         }
 668                 }
 669
 670
 671         /* If message is already reassembled, this must be a
 672          * retransmit and can be dropped. In this case item != NULL and so frag
 673          * does not need to be freed.
 674          */
 675         if (frag->reassembly == NULL)
 676                 {
 677                 unsigned char devnull [256];
 678
 679                 while (frag_len)
 680                         {
 681                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 682                                 devnull,
 683                                 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
 684                         if (i<=0) goto err;
 685                         frag_len -= i;
 686                         }
 687                 return DTLS1_HM_FRAGMENT_RETRY;
 688                 }
 689
 690         /* read the body of the fragment (header has already been read */
 691         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 692                 frag->fragment + msg_hdr->frag_off,frag_len,0);
 693         if ((unsigned long)i!=frag_len)
 694                 i=-1;
 695         if (i<=0)
 696                 goto err;
 697
 698         RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
 699                             (long)(msg_hdr->frag_off + frag_len));
 700
 701         RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
 702                                    is_complete);
 703
 704         if (is_complete)
 705                 {
 706                 OPENSSL_free(frag->reassembly);
 707                 frag->reassembly = NULL;
 708                 }
 709
 710         if (item == NULL)
 711                 {
 712                 item = pitem_new(seq64be, frag);
 713                 if (item == NULL)
 714                         {
 715                         i = -1;
 716                         goto err;
 717                         }
 718
 719                 item = pqueue_insert(s->d1->buffered_messages, item);
 720                 /* pqueue_insert fails iff a duplicate item is inserted.
 721                  * However, |item| cannot be a duplicate. If it were,
 722                  * |pqueue_find|, above, would have returned it and control
 723                  * would never have reached this branch. */
 724                 OPENSSL_assert(item != NULL);
 725                 }
 726
 727         return DTLS1_HM_FRAGMENT_RETRY;
 728
 729 err:
 730         if (frag != NULL && item == NULL) dtls1_hm_fragment_free(frag);
 731         *ok = 0;
 732         return i;
 733         }
 734
 735
 736 static int
 737 dtls1_process_out_of_seq_message(SSL *s, const struct hm_header_st* msg_hdr, int *ok)
 738 {
 739         int i=-1;
 740         hm_fragment *frag = NULL;
 741         pitem *item = NULL;
 742         unsigned char seq64be[8];
 743         unsigned long frag_len = msg_hdr->frag_len;
 744
 745         if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
 746                 goto err;
 747
 748         /* Try to find item in queue, to prevent duplicate entries */
 749         memset(seq64be,0,sizeof(seq64be));
 750         seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
 751         seq64be[7] = (unsigned char) msg_hdr->seq;
 752         item = pqueue_find(s->d1->buffered_messages, seq64be);
 753
 754         /* If we already have an entry and this one is a fragment,
 755          * don't discard it and rather try to reassemble it.
 756          */
 757         if (item != NULL && frag_len != msg_hdr->msg_len)
 758                 item = NULL;
 759
 760         /* Discard the message if sequence number was already there, is
 761          * too far in the future, already in the queue or if we received
 762          * a FINISHED before the SERVER_HELLO, which then must be a stale
 763          * retransmit.
 764          */
 765         if (msg_hdr->seq <= s->d1->handshake_read_seq ||
 766                 msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
 767                 (s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED))
 768                 {
 769                 unsigned char devnull [256];
 770
 771                 while (frag_len)
 772                         {
 773                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 774                                 devnull,
 775                                 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
 776                         if (i<=0) goto err;
 777                         frag_len -= i;
 778                         }
 779                 }
 780         else
 781                 {
 782                 if (frag_len != msg_hdr->msg_len)
 783                         return dtls1_reassemble_fragment(s, msg_hdr, ok);
 784
 785                 if (frag_len > dtls1_max_handshake_message_len(s))
 786                         goto err;
 787
 788                 frag = dtls1_hm_fragment_new(frag_len, 0);
 789                 if ( frag == NULL)
 790                         goto err;
 791
 792                 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 793
 794                 if (frag_len)
 795                         {
 796                         /* read the body of the fragment (header has already been read */
 797                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 798                                 frag->fragment,frag_len,0);
 799                         if ((unsigned long)i!=frag_len)
 800                                 i = -1;
 801                         if (i<=0)
 802                                 goto err;
 803                         }
 804
 805                 item = pitem_new(seq64be, frag);
 806                 if ( item == NULL)
 807                         goto err;
 808
 809                 item = pqueue_insert(s->d1->buffered_messages, item);
 810                 /* pqueue_insert fails iff a duplicate item is inserted.
 811                  * However, |item| cannot be a duplicate. If it were,
 812                  * |pqueue_find|, above, would have returned it. Then, either
 813                  * |frag_len| != |msg_hdr->msg_len| in which case |item| is set
 814                  * to NULL and it will have been processed with
 815                  * |dtls1_reassemble_fragment|, above, or the record will have
 816                  * been discarded. */
 817                 OPENSSL_assert(item != NULL);
 818                 }
 819
 820         return DTLS1_HM_FRAGMENT_RETRY;
 821
 822 err:
 823         if (frag != NULL && item == NULL) dtls1_hm_fragment_free(frag);
 824         *ok = 0;
 825         return i;
 826         }
 827
 828
 829 static long
 830 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
 831         {
 832         unsigned char wire[DTLS1_HM_HEADER_LENGTH];
 833         unsigned long len, frag_off, frag_len;
 834         int i,al;
 835         struct hm_header_st msg_hdr;
 836
 837         redo:
 838         /* see if we have the required fragment already */
 839         if ((frag_len = dtls1_retrieve_buffered_fragment(s,max,ok)) || *ok)
 840                 {
 841                 if (*ok)        s->init_num = frag_len;
 842                 return frag_len;
 843                 }
 844
 845         /* read handshake message header */
 846         i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,wire,
 847                 DTLS1_HM_HEADER_LENGTH, 0);
 848         if (i <= 0)     /* nbio, or an error */
 849                 {
 850                 s->rwstate=SSL_READING;
 851                 *ok = 0;
 852                 return i;
 853                 }
 854         /* Handshake fails if message header is incomplete */
 855         if (i != DTLS1_HM_HEADER_LENGTH)
 856                 {
 857                 al=SSL_AD_UNEXPECTED_MESSAGE;
 858                 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 859                 goto f_err;
 860                 }
 861
 862         /* parse the message fragment header */
 863         dtls1_get_message_header(wire, &msg_hdr);
 864
 865         /*
 866          * if this is a future (or stale) message it gets buffered
 867          * (or dropped)--no further processing at this time
 868          * While listening, we accept seq 1 (ClientHello with cookie)
 869          * although we're still expecting seq 0 (ClientHello)
 870          */
 871         if (msg_hdr.seq != s->d1->handshake_read_seq && !(s->d1->listen && msg_hdr.seq == 1))
 872                 return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
 873
 874         len = msg_hdr.msg_len;
 875         frag_off = msg_hdr.frag_off;
 876         frag_len = msg_hdr.frag_len;
 877
 878         if (frag_len && frag_len < len)
 879                 return dtls1_reassemble_fragment(s, &msg_hdr, ok);
 880
 881         if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
 882                 wire[0] == SSL3_MT_HELLO_REQUEST)
 883                 {
 884                 /* The server may always send 'Hello Request' messages --
 885                  * we are doing a handshake anyway now, so ignore them
 886                  * if their format is correct. Does not count for
 887                  * 'Finished' MAC. */
 888                 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0)
 889                         {
 890                         if (s->msg_callback)
 891                                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 892                                         wire, DTLS1_HM_HEADER_LENGTH, s,
 893                                         s->msg_callback_arg);
 894
 895                         s->init_num = 0;
 896                         goto redo;
 897                         }
 898                 else /* Incorrectly formated Hello request */
 899                         {
 900                         al=SSL_AD_UNEXPECTED_MESSAGE;
 901                         SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 902                         goto f_err;
 903                         }
 904                 }
 905
 906         if ((al=dtls1_preprocess_fragment(s,&msg_hdr,max)))
 907                 goto f_err;
 908
 909         /* XDTLS:  ressurect this when restart is in place */
 910         s->state=stn;
 911
 912         if ( frag_len > 0)
 913                 {
 914                 unsigned char *p=(unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 915
 916                 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 917                         &p[frag_off],frag_len,0);
 918                 /* XDTLS:  fix this--message fragments cannot span multiple packets */
 919                 if (i <= 0)
 920                         {
 921                         s->rwstate=SSL_READING;
 922                         *ok = 0;
 923                         return i;
 924                         }
 925                 }
 926         else
 927                 i = 0;
 928
 929         /* XDTLS:  an incorrectly formatted fragment should cause the
 930          * handshake to fail */
 931         if (i != (int)frag_len)
 932                 {
 933                 al=SSL3_AD_ILLEGAL_PARAMETER;
 934                 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL3_AD_ILLEGAL_PARAMETER);
 935                 goto f_err;
 936                 }
 937
 938         *ok = 1;
 939
 940         /* Note that s->init_num is *not* used as current offset in
 941          * s->init_buf->data, but as a counter summing up fragments'
 942          * lengths: as soon as they sum up to handshake packet
 943          * length, we assume we have got all the fragments. */
 944         s->init_num = frag_len;
 945         return frag_len;
 946
 947 f_err:
 948         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 949         s->init_num = 0;
 950
 951         *ok=0;
 952         return(-1);
 953         }
 954
 955 /* for these 2 messages, we need to
 956  * ssl->enc_read_ctx                    re-init
 957  * ssl->s3->read_sequence               zero
 958  * ssl->s3->read_mac_secret             re-init
 959  * ssl->session->read_sym_enc           assign
 960  * ssl->session->read_compression       assign
 961  * ssl->session->read_hash              assign
 962  */
 963 int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
 964         {
 965         unsigned char *p;
 966
 967         if (s->state == a)
 968                 {
 969                 p=(unsigned char *)s->init_buf->data;
 970                 *p++=SSL3_MT_CCS;
 971                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
 972                 s->init_num=DTLS1_CCS_HEADER_LENGTH;
 973
 974                 if (s->version == DTLS1_BAD_VER) {
 975                         s->d1->next_handshake_write_seq++;
 976                         s2n(s->d1->handshake_write_seq,p);
 977                         s->init_num+=2;
 978                 }
 979
 980                 s->init_off=0;
 981
 982                 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
 983                         s->d1->handshake_write_seq, 0, 0);
 984
 985                 /* buffer the message to handle re-xmits */
 986                 dtls1_buffer_message(s, 1);
 987
 988                 s->state=b;
 989                 }
 990
 991         /* SSL3_ST_CW_CHANGE_B */
 992         return(dtls1_do_write(s,SSL3_RT_CHANGE_CIPHER_SPEC));
 993         }
 994
 995 int dtls1_read_failed(SSL *s, int code)
 996         {
 997         if ( code > 0)
 998                 {
 999                 fprintf( stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
1000                 return 1;
1001                 }
1002
1003         if (!dtls1_is_timer_expired(s))
1004                 {
1005                 /* not a timeout, none of our business,
1006                    let higher layers handle this.  in fact it's probably an error */
1007                 return code;
1008                 }
1009
1010 #ifndef OPENSSL_NO_HEARTBEATS
1011         if (!SSL_in_init(s) && !s->tlsext_hb_pending)  /* done, no need to send a retransmit */
1012 #else
1013         if (!SSL_in_init(s))  /* done, no need to send a retransmit */
1014 #endif
1015                 {
1016                 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
1017                 return code;
1018                 }
1019
1020 #if 0 /* for now, each alert contains only one record number */
1021         item = pqueue_peek(state->rcvd_records);
1022         if ( item )
1023                 {
1024                 /* send an alert immediately for all the missing records */
1025                 }
1026         else
1027 #endif
1028
1029 #if 0  /* no more alert sending, just retransmit the last set of messages */
1030         if ( state->timeout.read_timeouts >= DTLS1_TMO_READ_COUNT)
1031                 ssl3_send_alert(s,SSL3_AL_WARNING,
1032                         DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
1033 #endif
1034
1035         return dtls1_handle_timeout(s);
1036         }
1037
1038 int
1039 dtls1_get_queue_priority(unsigned short seq, int is_ccs)
1040         {
1041         /* The index of the retransmission queue actually is the message sequence number,
1042          * since the queue only contains messages of a single handshake. However, the
1043          * ChangeCipherSpec has no message sequence number and so using only the sequence
1044          * will result in the CCS and Finished having the same index. To prevent this,
1045          * the sequence number is multiplied by 2. In case of a CCS 1 is subtracted.
1046          * This does not only differ CSS and Finished, it also maintains the order of the
1047          * index (important for priority queues) and fits in the unsigned short variable.
1048          */
1049         return seq * 2 - is_ccs;
1050         }
1051
1052 int
1053 dtls1_retransmit_buffered_messages(SSL *s)
1054         {
1055         pqueue sent = s->d1->sent_messages;
1056         piterator iter;
1057         pitem *item;
1058         hm_fragment *frag;
1059         int found = 0;
1060
1061         iter = pqueue_iterator(sent);
1062
1063         for ( item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter))
1064                 {
1065                 frag = (hm_fragment *)item->data;
1066                         if ( dtls1_retransmit_message(s,
1067                                 (unsigned short)dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs),
1068                                 0, &found) <= 0 && found)
1069                         {
1070                         fprintf(stderr, "dtls1_retransmit_message() failed\n");
1071                         return -1;
1072                         }
1073                 }
1074
1075         return 1;
1076         }
1077
1078 int
1079 dtls1_buffer_message(SSL *s, int is_ccs)
1080         {
1081         pitem *item;
1082         hm_fragment *frag;
1083         unsigned char seq64be[8];
1084
1085         /* this function is called immediately after a message has
1086          * been serialized */
1087         OPENSSL_assert(s->init_off == 0);
1088
1089         frag = dtls1_hm_fragment_new(s->init_num, 0);
1090         if (!frag)
1091                 return 0;
1092
1093         memcpy(frag->fragment, s->init_buf->data, s->init_num);
1094
1095         if ( is_ccs)
1096                 {
1097                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1098                                DTLS1_CCS_HEADER_LENGTH == (unsigned int)s->init_num);
1099                 }
1100         else
1101                 {
1102                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1103                         DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
1104                 }
1105
1106         frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1107         frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1108         frag->msg_header.type = s->d1->w_msg_hdr.type;
1109         frag->msg_header.frag_off = 0;
1110         frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1111         frag->msg_header.is_ccs = is_ccs;
1112
1113         /* save current state*/
1114         frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
1115         frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
1116         frag->msg_header.saved_retransmit_state.compress = s->compress;
1117         frag->msg_header.saved_retransmit_state.session = s->session;
1118         frag->msg_header.saved_retransmit_state.epoch = s->d1->w_epoch;
1119
1120         memset(seq64be,0,sizeof(seq64be));
1121         seq64be[6] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1122                                                                                                                   frag->msg_header.is_ccs)>>8);
1123         seq64be[7] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1124                                                                                                                   frag->msg_header.is_ccs));
1125
1126         item = pitem_new(seq64be, frag);
1127         if ( item == NULL)
1128                 {
1129                 dtls1_hm_fragment_free(frag);
1130                 return 0;
1131                 }
1132
1133 #if 0
1134         fprintf( stderr, "buffered messge: \ttype = %xx\n", msg_buf->type);
1135         fprintf( stderr, "\t\t\t\t\tlen = %d\n", msg_buf->len);
1136         fprintf( stderr, "\t\t\t\t\tseq_num = %d\n", msg_buf->seq_num);
1137 #endif
1138
1139         pqueue_insert(s->d1->sent_messages, item);
1140         return 1;
1141         }
1142
1143 int
1144 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
1145         int *found)
1146         {
1147         int ret;
1148         /* XDTLS: for now assuming that read/writes are blocking */
1149         pitem *item;
1150         hm_fragment *frag ;
1151         unsigned long header_length;
1152         unsigned char seq64be[8];
1153         struct dtls1_retransmit_state saved_state;
1154         unsigned char save_write_sequence[8];
1155
1156         /*
1157           OPENSSL_assert(s->init_num == 0);
1158           OPENSSL_assert(s->init_off == 0);
1159          */
1160
1161         /* XDTLS:  the requested message ought to be found, otherwise error */
1162         memset(seq64be,0,sizeof(seq64be));
1163         seq64be[6] = (unsigned char)(seq>>8);
1164         seq64be[7] = (unsigned char)seq;
1165
1166         item = pqueue_find(s->d1->sent_messages, seq64be);
1167         if ( item == NULL)
1168                 {
1169                 fprintf(stderr, "retransmit:  message %d non-existant\n", seq);
1170                 *found = 0;
1171                 return 0;
1172                 }
1173
1174         *found = 1;
1175         frag = (hm_fragment *)item->data;
1176
1177         if ( frag->msg_header.is_ccs)
1178                 header_length = DTLS1_CCS_HEADER_LENGTH;
1179         else
1180                 header_length = DTLS1_HM_HEADER_LENGTH;
1181
1182         memcpy(s->init_buf->data, frag->fragment,
1183                 frag->msg_header.msg_len + header_length);
1184                 s->init_num = frag->msg_header.msg_len + header_length;
1185
1186         dtls1_set_message_header_int(s, frag->msg_header.type,
1187                 frag->msg_header.msg_len, frag->msg_header.seq, 0,
1188                 frag->msg_header.frag_len);
1189
1190         /* save current state */
1191         saved_state.enc_write_ctx = s->enc_write_ctx;
1192         saved_state.write_hash = s->write_hash;
1193         saved_state.compress = s->compress;
1194         saved_state.session = s->session;
1195         saved_state.epoch = s->d1->w_epoch;
1196         saved_state.epoch = s->d1->w_epoch;
1197
1198         s->d1->retransmitting = 1;
1199
1200         /* restore state in which the message was originally sent */
1201         s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
1202         s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
1203         s->compress = frag->msg_header.saved_retransmit_state.compress;
1204         s->session = frag->msg_header.saved_retransmit_state.session;
1205         s->d1->w_epoch = frag->msg_header.saved_retransmit_state.epoch;
1206
1207         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1208         {
1209                 memcpy(save_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1210                 memcpy(s->s3->write_sequence, s->d1->last_write_sequence, sizeof(s->s3->write_sequence));
1211         }
1212
1213         ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1214                                                  SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1215
1216         /* restore current state */
1217         s->enc_write_ctx = saved_state.enc_write_ctx;
1218         s->write_hash = saved_state.write_hash;
1219         s->compress = saved_state.compress;
1220         s->session = saved_state.session;
1221         s->d1->w_epoch = saved_state.epoch;
1222
1223         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1224         {
1225                 memcpy(s->d1->last_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1226                 memcpy(s->s3->write_sequence, save_write_sequence, sizeof(s->s3->write_sequence));
1227         }
1228
1229         s->d1->retransmitting = 0;
1230
1231         (void)BIO_flush(SSL_get_wbio(s));
1232         return ret;
1233         }
1234
1235 /* call this function when the buffered messages are no longer needed */
1236 void
1237 dtls1_clear_record_buffer(SSL *s)
1238         {
1239         pitem *item;
1240
1241         for(item = pqueue_pop(s->d1->sent_messages);
1242                 item != NULL; item = pqueue_pop(s->d1->sent_messages))
1243                 {
1244                 dtls1_hm_fragment_free((hm_fragment *)item->data);
1245                 pitem_free(item);
1246                 }
1247         }
1248
1249
1250 unsigned char *
1251 dtls1_set_message_header(SSL *s, unsigned char *p, unsigned char mt,
1252                         unsigned long len, unsigned long frag_off, unsigned long frag_len)
1253         {
1254         /* Don't change sequence numbers while listening */
1255         if (frag_off == 0 && !s->d1->listen)
1256                 {
1257                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1258                 s->d1->next_handshake_write_seq++;
1259                 }
1260
1261         dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1262                 frag_off, frag_len);
1263
1264         return p += DTLS1_HM_HEADER_LENGTH;
1265         }
1266
1267
1268 /* don't actually do the writing, wait till the MTU has been retrieved */
1269 static void
1270 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1271                             unsigned long len, unsigned short seq_num, unsigned long frag_off,
1272                             unsigned long frag_len)
1273         {
1274         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1275
1276         msg_hdr->type = mt;
1277         msg_hdr->msg_len = len;
1278         msg_hdr->seq = seq_num;
1279         msg_hdr->frag_off = frag_off;
1280         msg_hdr->frag_len = frag_len;
1281         }
1282
1283 static void
1284 dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1285                         unsigned long frag_len)
1286         {
1287         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1288
1289         msg_hdr->frag_off = frag_off;
1290         msg_hdr->frag_len = frag_len;
1291         }
1292
1293 static unsigned char *
1294 dtls1_write_message_header(SSL *s, unsigned char *p)
1295         {
1296         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1297
1298         *p++ = msg_hdr->type;
1299         l2n3(msg_hdr->msg_len, p);
1300
1301         s2n(msg_hdr->seq, p);
1302         l2n3(msg_hdr->frag_off, p);
1303         l2n3(msg_hdr->frag_len, p);
1304
1305         return p;
1306         }
1307
1308 unsigned int
1309 dtls1_link_min_mtu(void)
1310         {
1311         return (g_probable_mtu[(sizeof(g_probable_mtu) /
1312                 sizeof(g_probable_mtu[0])) - 1]);
1313         }
1314
1315 unsigned int
1316 dtls1_min_mtu(SSL *s)
1317         {
1318         return dtls1_link_min_mtu()-BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
1319         }
1320
1321 static void
1322 dtls1_guess_mtu(SSL *s)
1323         {
1324         unsigned int curr_mtu;
1325         unsigned int i;
1326         unsigned int mtu_ovr;
1327
1328         curr_mtu = s->d1->mtu;
1329         mtu_ovr = BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
1330
1331         if ( curr_mtu == 0 )
1332                 {
1333                 curr_mtu = g_probable_mtu[0] - mtu_ovr;
1334                 }
1335         else
1336                 {
1337                 for ( i = 0; i < sizeof(g_probable_mtu)/sizeof(g_probable_mtu[0]); i++)
1338                         if ( curr_mtu > g_probable_mtu[i] - mtu_ovr)
1339                                 return g_probable_mtu[i] - mtu_ovr;
1340                 }
1341         s->d1->mtu = curr_mtu;
1342         }
1343
1344 void
1345 dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1346         {
1347         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
1348         msg_hdr->type = *(data++);
1349         n2l3(data, msg_hdr->msg_len);
1350
1351         n2s(data, msg_hdr->seq);
1352         n2l3(data, msg_hdr->frag_off);
1353         n2l3(data, msg_hdr->frag_len);
1354         }
1355
1356 void
1357 dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
1358         {
1359         memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
1360
1361         ccs_hdr->type = *(data++);
1362         }
1363
1364 int dtls1_shutdown(SSL *s)
1365         {
1366         int ret;
1367 #ifndef OPENSSL_NO_SCTP
1368         if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
1369             !(s->shutdown & SSL_SENT_SHUTDOWN))
1370                 {
1371                 ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
1372                 if (ret < 0) return -1;
1373
1374                 if (ret == 0)
1375                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1, NULL);
1376                 }
1377 #endif
1378         ret = ssl3_shutdown(s);
1379 #ifndef OPENSSL_NO_SCTP
1380         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
1381 #endif
1382         return ret;
1383         }
1384
1385 #ifndef OPENSSL_NO_HEARTBEATS
1386 int
1387 dtls1_process_heartbeat(SSL *s)
1388         {
1389         unsigned char *p = &s->s3->rrec.data[0], *pl;
1390         unsigned short hbtype;
1391         unsigned int payload;
1392         unsigned int padding = 16; /* Use minimum padding */
1393
1394         if (s->msg_callback)
1395                 s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
1396                         &s->s3->rrec.data[0], s->s3->rrec.length,
1397                         s, s->msg_callback_arg);
1398
1399         /* Read type and payload length first */
1400         if (1 + 2 + 16 > s->s3->rrec.length)
1401                 return 0; /* silently discard */
1402         if (s->s3->rrec.length > SSL3_RT_MAX_PLAIN_LENGTH)
1403                 return 0; /* silently discard per RFC 6520 sec. 4 */
1404
1405         hbtype = *p++;
1406         n2s(p, payload);
1407         if (1 + 2 + payload + 16 > s->s3->rrec.length)
1408                 return 0; /* silently discard per RFC 6520 sec. 4 */
1409         pl = p;
1410
1411         if (hbtype == TLS1_HB_REQUEST)
1412                 {
1413                 unsigned char *buffer, *bp;
1414                 unsigned int write_length = 1 /* heartbeat type */ +
1415                                             2 /* heartbeat length */ +
1416                                             payload + padding;
1417                 int r;
1418
1419                 if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
1420                         return 0;
1421
1422                 /* Allocate memory for the response, size is 1 byte
1423                  * message type, plus 2 bytes payload length, plus
1424                  * payload, plus padding
1425                  */
1426                 buffer = OPENSSL_malloc(write_length);
1427                 bp = buffer;
1428
1429                 /* Enter response type, length and copy payload */
1430                 *bp++ = TLS1_HB_RESPONSE;
1431                 s2n(payload, bp);
1432                 memcpy(bp, pl, payload);
1433                 bp += payload;
1434                 /* Random padding */
1435                 RAND_pseudo_bytes(bp, padding);
1436
1437                 r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
1438
1439                 if (r >= 0 && s->msg_callback)
1440                         s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1441                                 buffer, write_length,
1442                                 s, s->msg_callback_arg);
1443
1444                 OPENSSL_free(buffer);
1445
1446                 if (r < 0)
1447                         return r;
1448                 }
1449         else if (hbtype == TLS1_HB_RESPONSE)
1450                 {
1451                 unsigned int seq;
1452
1453                 /* We only send sequence numbers (2 bytes unsigned int),
1454                  * and 16 random bytes, so we just try to read the
1455                  * sequence number */
1456                 n2s(pl, seq);
1457
1458                 if (payload == 18 && seq == s->tlsext_hb_seq)
1459                         {
1460                         dtls1_stop_timer(s);
1461                         s->tlsext_hb_seq++;
1462                         s->tlsext_hb_pending = 0;
1463                         }
1464                 }
1465
1466         return 0;
1467         }
1468
1469 int
1470 dtls1_heartbeat(SSL *s)
1471         {
1472         unsigned char *buf, *p;
1473         int ret;
1474         unsigned int payload = 18; /* Sequence number + random bytes */
1475         unsigned int padding = 16; /* Use minimum padding */
1476
1477         /* Only send if peer supports and accepts HB requests... */
1478         if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
1479             s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS)
1480                 {
1481                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
1482                 return -1;
1483                 }
1484
1485         /* ...and there is none in flight yet... */
1486         if (s->tlsext_hb_pending)
1487                 {
1488                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PENDING);
1489                 return -1;
1490                 }
1491
1492         /* ...and no handshake in progress. */
1493         if (SSL_in_init(s) || s->in_handshake)
1494                 {
1495                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_UNEXPECTED_MESSAGE);
1496                 return -1;
1497                 }
1498
1499         /* Check if padding is too long, payload and padding
1500          * must not exceed 2^14 - 3 = 16381 bytes in total.
1501          */
1502         OPENSSL_assert(payload + padding <= 16381);
1503
1504         /* Create HeartBeat message, we just use a sequence number
1505          * as payload to distuingish different messages and add
1506          * some random stuff.
1507          *  - Message Type, 1 byte
1508          *  - Payload Length, 2 bytes (unsigned int)
1509          *  - Payload, the sequence number (2 bytes uint)
1510          *  - Payload, random bytes (16 bytes uint)
1511          *  - Padding
1512          */
1513         buf = OPENSSL_malloc(1 + 2 + payload + padding);
1514         p = buf;
1515         /* Message Type */
1516         *p++ = TLS1_HB_REQUEST;
1517         /* Payload length (18 bytes here) */
1518         s2n(payload, p);
1519         /* Sequence number */
1520         s2n(s->tlsext_hb_seq, p);
1521         /* 16 random bytes */
1522         RAND_pseudo_bytes(p, 16);
1523         p += 16;
1524         /* Random padding */
1525         RAND_pseudo_bytes(p, padding);
1526
1527         ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
1528         if (ret >= 0)
1529                 {
1530                 if (s->msg_callback)
1531                         s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1532                                 buf, 3 + payload + padding,
1533                                 s, s->msg_callback_arg);
1534
1535                 dtls1_start_timer(s);
1536                 s->tlsext_hb_pending = 1;
1537                 }
1538
1539         OPENSSL_free(buf);
1540
1541         return ret;
1542         }
1543 #endif