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