ssl/record/rec_layer_d1.c

   1 /*
   2  * Copyright 2005-2024 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <stdio.h>
  11 #include <errno.h>
  12 #include "../ssl_local.h"
  13 #include <openssl/evp.h>
  14 #include <openssl/buffer.h>
  15 #include "record_local.h"
  16 #include "internal/packet.h"
  17 #include "internal/cryptlib.h"
  18
  19 int DTLS_RECORD_LAYER_new(RECORD_LAYER *rl)
  20 {
  21     DTLS_RECORD_LAYER *d;
  22
  23     if ((d = OPENSSL_malloc(sizeof(*d))) == NULL)
  24         return 0;
  25
  26     rl->d = d;
  27
  28     d->buffered_app_data = pqueue_new();
  29
  30     if (d->buffered_app_data == NULL) {
  31         OPENSSL_free(d);
  32         rl->d = NULL;
  33         return 0;
  34     }
  35
  36     return 1;
  37 }
  38
  39 void DTLS_RECORD_LAYER_free(RECORD_LAYER *rl)
  40 {
  41     if (rl->d == NULL)
  42         return;
  43
  44     DTLS_RECORD_LAYER_clear(rl);
  45     pqueue_free(rl->d->buffered_app_data);
  46     OPENSSL_free(rl->d);
  47     rl->d = NULL;
  48 }
  49
  50 void DTLS_RECORD_LAYER_clear(RECORD_LAYER *rl)
  51 {
  52     DTLS_RECORD_LAYER *d;
  53     pitem *item = NULL;
  54     TLS_RECORD *rec;
  55     pqueue *buffered_app_data;
  56
  57     d = rl->d;
  58
  59     while ((item = pqueue_pop(d->buffered_app_data)) != NULL) {
  60         rec = (TLS_RECORD *)item->data;
  61
  62         if (rl->s->options & SSL_OP_CLEANSE_PLAINTEXT)
  63             OPENSSL_cleanse(rec->allocdata, rec->length);
  64         OPENSSL_free(rec->allocdata);
  65         OPENSSL_free(item->data);
  66         pitem_free(item);
  67     }
  68
  69     buffered_app_data = d->buffered_app_data;
  70     memset(d, 0, sizeof(*d));
  71     d->buffered_app_data = buffered_app_data;
  72 }
  73
  74 static int dtls_buffer_record(SSL_CONNECTION *s, TLS_RECORD *rec)
  75 {
  76     TLS_RECORD *rdata;
  77     pitem *item;
  78     struct pqueue_st *queue = s->rlayer.d->buffered_app_data;
  79
  80     /* Limit the size of the queue to prevent DOS attacks */
  81     if (pqueue_size(queue) >= 100)
  82         return 0;
  83
  84     /* We don't buffer partially read records */
  85     if (!ossl_assert(rec->off == 0))
  86         return -1;
  87
  88     rdata = OPENSSL_malloc(sizeof(*rdata));
  89     item = pitem_new(rec->seq_num, rdata);
  90     if (rdata == NULL || item == NULL) {
  91         OPENSSL_free(rdata);
  92         pitem_free(item);
  93         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
  94         return -1;
  95     }
  96
  97     *rdata = *rec;
  98     /*
  99      * We will release the record from the record layer soon, so we take a copy
 100      * now. Copying data isn't good - but this should be infrequent so we
 101      * accept it here.
 102      */
 103     rdata->data = rdata->allocdata = OPENSSL_memdup(rec->data, rec->length);
 104     if (rdata->data == NULL) {
 105         OPENSSL_free(rdata);
 106         pitem_free(item);
 107         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_CRYPTO_LIB);
 108         return -1;
 109     }
 110     /*
 111      * We use a NULL rechandle to indicate that the data field has been
 112      * allocated by us.
 113      */
 114     rdata->rechandle = NULL;
 115
 116     item->data = rdata;
 117
 118 #ifndef OPENSSL_NO_SCTP
 119     /* Store bio_dgram_sctp_rcvinfo struct */
 120     if (BIO_dgram_is_sctp(s->rbio) &&
 121         (ossl_statem_get_state(s) == TLS_ST_SR_FINISHED
 122          || ossl_statem_get_state(s) == TLS_ST_CR_FINISHED)) {
 123         BIO_ctrl(s->rbio, BIO_CTRL_DGRAM_SCTP_GET_RCVINFO,
 124                  sizeof(rdata->recordinfo), &rdata->recordinfo);
 125     }
 126 #endif
 127
 128     if (pqueue_insert(queue, item) == NULL) {
 129         /* Must be a duplicate so ignore it */
 130         OPENSSL_free(rdata->allocdata);
 131         OPENSSL_free(rdata);
 132         pitem_free(item);
 133     }
 134
 135     return 1;
 136 }
 137
 138 /* Unbuffer a previously buffered TLS_RECORD structure if any */
 139 static void dtls_unbuffer_record(SSL_CONNECTION *s)
 140 {
 141     TLS_RECORD *rdata;
 142     pitem *item;
 143
 144     /* If we already have records to handle then do nothing */
 145     if (s->rlayer.curr_rec < s->rlayer.num_recs)
 146         return;
 147
 148     item = pqueue_pop(s->rlayer.d->buffered_app_data);
 149     if (item != NULL) {
 150         rdata = (TLS_RECORD *)item->data;
 151
 152         s->rlayer.tlsrecs[0] = *rdata;
 153         s->rlayer.num_recs = 1;
 154         s->rlayer.curr_rec = 0;
 155
 156 #ifndef OPENSSL_NO_SCTP
 157         /* Restore bio_dgram_sctp_rcvinfo struct */
 158         if (BIO_dgram_is_sctp(s->rbio)) {
 159             BIO_ctrl(s->rbio, BIO_CTRL_DGRAM_SCTP_SET_RCVINFO,
 160                      sizeof(rdata->recordinfo), &rdata->recordinfo);
 161         }
 162 #endif
 163
 164         OPENSSL_free(item->data);
 165         pitem_free(item);
 166     }
 167 }
 168
 169 /*-
 170  * Return up to 'len' payload bytes received in 'type' records.
 171  * 'type' is one of the following:
 172  *
 173  *   -  SSL3_RT_HANDSHAKE
 174  *   -  SSL3_RT_APPLICATION_DATA (when ssl3_read calls us)
 175  *   -  0 (during a shutdown, no data has to be returned)
 176  *
 177  * If we don't have stored data to work from, read a SSL/TLS record first
 178  * (possibly multiple records if we still don't have anything to return).
 179  *
 180  * This function must handle any surprises the peer may have for us, such as
 181  * Alert records (e.g. close_notify) or renegotiation requests. ChangeCipherSpec
 182  * messages are treated as if they were handshake messages *if* the |recd_type|
 183  * argument is non NULL.
 184  * Also if record payloads contain fragments too small to process, we store
 185  * them until there is enough for the respective protocol (the record protocol
 186  * may use arbitrary fragmentation and even interleaving):
 187  *     Change cipher spec protocol
 188  *             just 1 byte needed, no need for keeping anything stored
 189  *     Alert protocol
 190  *             2 bytes needed (AlertLevel, AlertDescription)
 191  *     Handshake protocol
 192  *             4 bytes needed (HandshakeType, uint24 length) -- we just have
 193  *             to detect unexpected Client Hello and Hello Request messages
 194  *             here, anything else is handled by higher layers
 195  *     Application data protocol
 196  *             none of our business
 197  */
 198 int dtls1_read_bytes(SSL *s, uint8_t type, uint8_t *recvd_type,
 199                      unsigned char *buf, size_t len,
 200                      int peek, size_t *readbytes)
 201 {
 202     int i, j, ret;
 203     size_t n;
 204     TLS_RECORD *rr;
 205     void (*cb) (const SSL *ssl, int type2, int val) = NULL;
 206     SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL(s);
 207
 208     if (sc == NULL)
 209         return -1;
 210
 211     if ((type && (type != SSL3_RT_APPLICATION_DATA) &&
 212          (type != SSL3_RT_HANDSHAKE)) ||
 213         (peek && (type != SSL3_RT_APPLICATION_DATA))) {
 214         SSLfatal(sc, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 215         return -1;
 216     }
 217
 218     if (!ossl_statem_get_in_handshake(sc) && SSL_in_init(s)) {
 219         /* type == SSL3_RT_APPLICATION_DATA */
 220         i = sc->handshake_func(s);
 221         /* SSLfatal() already called if appropriate */
 222         if (i < 0)
 223             return i;
 224         if (i == 0)
 225             return -1;
 226     }
 227
 228  start:
 229     sc->rwstate = SSL_NOTHING;
 230
 231     /*
 232      * We are not handshaking and have no data yet, so process data buffered
 233      * during the last handshake in advance, if any.
 234      */
 235     if (SSL_is_init_finished(s))
 236         dtls_unbuffer_record(sc);
 237
 238     /* Check for timeout */
 239     if (dtls1_handle_timeout(sc) > 0) {
 240         goto start;
 241     } else if (ossl_statem_in_error(sc)) {
 242         /* dtls1_handle_timeout() has failed with a fatal error */
 243         return -1;
 244     }
 245
 246     /* get new packet if necessary */
 247     if (sc->rlayer.curr_rec >= sc->rlayer.num_recs) {
 248         sc->rlayer.curr_rec = sc->rlayer.num_recs = 0;
 249         do {
 250             rr = &sc->rlayer.tlsrecs[sc->rlayer.num_recs];
 251
 252             ret = HANDLE_RLAYER_READ_RETURN(sc,
 253                     sc->rlayer.rrlmethod->read_record(sc->rlayer.rrl,
 254                                                       &rr->rechandle,
 255                                                       &rr->version, &rr->type,
 256                                                       &rr->data, &rr->length,
 257                                                       &rr->epoch, rr->seq_num));
 258             if (ret <= 0) {
 259                 ret = dtls1_read_failed(sc, ret);
 260                 /*
 261                 * Anything other than a timeout is an error. SSLfatal() already
 262                 * called if appropriate.
 263                 */
 264                 if (ret <= 0)
 265                     return ret;
 266                 else
 267                     goto start;
 268             }
 269             rr->off = 0;
 270             sc->rlayer.num_recs++;
 271         } while (sc->rlayer.rrlmethod->processed_read_pending(sc->rlayer.rrl)
 272                  && sc->rlayer.num_recs < SSL_MAX_PIPELINES);
 273     }
 274     rr = &sc->rlayer.tlsrecs[sc->rlayer.curr_rec];
 275
 276     /*
 277      * Reset the count of consecutive warning alerts if we've got a non-empty
 278      * record that isn't an alert.
 279      */
 280     if (rr->type != SSL3_RT_ALERT && rr->length != 0)
 281         sc->rlayer.alert_count = 0;
 282
 283     /* we now have a packet which can be read and processed */
 284
 285     if (sc->s3.change_cipher_spec /* set when we receive ChangeCipherSpec,
 286                                   * reset by ssl3_get_finished */
 287         && (rr->type != SSL3_RT_HANDSHAKE)) {
 288         /*
 289          * We now have application data between CCS and Finished. Most likely
 290          * the packets were reordered on their way, so buffer the application
 291          * data for later processing rather than dropping the connection.
 292          */
 293         if (dtls_buffer_record(sc, rr) < 0) {
 294             /* SSLfatal() already called */
 295             return -1;
 296         }
 297         if (!ssl_release_record(sc, rr, 0))
 298             return -1;
 299         goto start;
 300     }
 301
 302     /*
 303      * If the other end has shut down, throw anything we read away (even in
 304      * 'peek' mode)
 305      */
 306     if (sc->shutdown & SSL_RECEIVED_SHUTDOWN) {
 307         if (!ssl_release_record(sc, rr, 0))
 308             return -1;
 309         sc->rwstate = SSL_NOTHING;
 310         return 0;
 311     }
 312
 313     if (type == rr->type
 314         || (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC
 315             && type == SSL3_RT_HANDSHAKE && recvd_type != NULL)) {
 316         /*
 317          * SSL3_RT_APPLICATION_DATA or
 318          * SSL3_RT_HANDSHAKE or
 319          * SSL3_RT_CHANGE_CIPHER_SPEC
 320          */
 321         /*
 322          * make sure that we are not getting application data when we are
 323          * doing a handshake for the first time
 324          */
 325         if (SSL_in_init(s) && (type == SSL3_RT_APPLICATION_DATA)
 326                 && (SSL_IS_FIRST_HANDSHAKE(sc))) {
 327             SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE,
 328                      SSL_R_APP_DATA_IN_HANDSHAKE);
 329             return -1;
 330         }
 331
 332         if (recvd_type != NULL)
 333             *recvd_type = rr->type;
 334
 335         if (len == 0) {
 336             /*
 337              * Release a zero length record. This ensures multiple calls to
 338              * SSL_read() with a zero length buffer will eventually cause
 339              * SSL_pending() to report data as being available.
 340              */
 341             if (rr->length == 0 && !ssl_release_record(sc, rr, 0))
 342                 return -1;
 343             return 0;
 344         }
 345
 346         if (len > rr->length)
 347             n = rr->length;
 348         else
 349             n = len;
 350
 351         memcpy(buf, &(rr->data[rr->off]), n);
 352         if (peek) {
 353             if (rr->length == 0 && !ssl_release_record(sc, rr, 0))
 354                 return -1;
 355         } else {
 356             if (!ssl_release_record(sc, rr, n))
 357                 return -1;
 358         }
 359 #ifndef OPENSSL_NO_SCTP
 360         /*
 361          * We might had to delay a close_notify alert because of reordered
 362          * app data. If there was an alert and there is no message to read
 363          * anymore, finally set shutdown.
 364          */
 365         if (BIO_dgram_is_sctp(SSL_get_rbio(s)) &&
 366             sc->d1->shutdown_received
 367             && BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s)) <= 0) {
 368             sc->shutdown |= SSL_RECEIVED_SHUTDOWN;
 369             return 0;
 370         }
 371 #endif
 372         *readbytes = n;
 373         return 1;
 374     }
 375
 376     /*
 377      * If we get here, then type != rr->type; if we have a handshake message,
 378      * then it was unexpected (Hello Request or Client Hello).
 379      */
 380
 381     if (rr->type == SSL3_RT_ALERT) {
 382         unsigned int alert_level, alert_descr;
 383         const unsigned char *alert_bytes = rr->data + rr->off;
 384         PACKET alert;
 385
 386         if (!PACKET_buf_init(&alert, alert_bytes, rr->length)
 387                 || !PACKET_get_1(&alert, &alert_level)
 388                 || !PACKET_get_1(&alert, &alert_descr)
 389                 || PACKET_remaining(&alert) != 0) {
 390             SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE, SSL_R_INVALID_ALERT);
 391             return -1;
 392         }
 393
 394         if (sc->msg_callback)
 395             sc->msg_callback(0, sc->version, SSL3_RT_ALERT, alert_bytes, 2, s,
 396                              sc->msg_callback_arg);
 397
 398         if (sc->info_callback != NULL)
 399             cb = sc->info_callback;
 400         else if (s->ctx->info_callback != NULL)
 401             cb = s->ctx->info_callback;
 402
 403         if (cb != NULL) {
 404             j = (alert_level << 8) | alert_descr;
 405             cb(s, SSL_CB_READ_ALERT, j);
 406         }
 407
 408         if (alert_level == SSL3_AL_WARNING) {
 409             sc->s3.warn_alert = alert_descr;
 410             if (!ssl_release_record(sc, rr, 0))
 411                 return -1;
 412
 413             sc->rlayer.alert_count++;
 414             if (sc->rlayer.alert_count == MAX_WARN_ALERT_COUNT) {
 415                 SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE,
 416                          SSL_R_TOO_MANY_WARN_ALERTS);
 417                 return -1;
 418             }
 419
 420             if (alert_descr == SSL_AD_CLOSE_NOTIFY) {
 421 #ifndef OPENSSL_NO_SCTP
 422                 /*
 423                  * With SCTP and streams the socket may deliver app data
 424                  * after a close_notify alert. We have to check this first so
 425                  * that nothing gets discarded.
 426                  */
 427                 if (BIO_dgram_is_sctp(SSL_get_rbio(s)) &&
 428                     BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s)) > 0) {
 429                     sc->d1->shutdown_received = 1;
 430                     sc->rwstate = SSL_READING;
 431                     BIO_clear_retry_flags(SSL_get_rbio(s));
 432                     BIO_set_retry_read(SSL_get_rbio(s));
 433                     return -1;
 434                 }
 435 #endif
 436                 sc->shutdown |= SSL_RECEIVED_SHUTDOWN;
 437                 return 0;
 438             }
 439         } else if (alert_level == SSL3_AL_FATAL) {
 440             sc->rwstate = SSL_NOTHING;
 441             sc->s3.fatal_alert = alert_descr;
 442             SSLfatal_data(sc, SSL_AD_NO_ALERT,
 443                           SSL_AD_REASON_OFFSET + alert_descr,
 444                           "SSL alert number %d", alert_descr);
 445             sc->shutdown |= SSL_RECEIVED_SHUTDOWN;
 446             if (!ssl_release_record(sc, rr, 0))
 447                 return -1;
 448             SSL_CTX_remove_session(sc->session_ctx, sc->session);
 449             return 0;
 450         } else {
 451             SSLfatal(sc, SSL_AD_ILLEGAL_PARAMETER, SSL_R_UNKNOWN_ALERT_TYPE);
 452             return -1;
 453         }
 454
 455         goto start;
 456     }
 457
 458     if (sc->shutdown & SSL_SENT_SHUTDOWN) { /* but we have not received a
 459                                             * shutdown */
 460         sc->rwstate = SSL_NOTHING;
 461         if (!ssl_release_record(sc, rr, 0))
 462             return -1;
 463         return 0;
 464     }
 465
 466     if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC) {
 467         /*
 468          * We can't process a CCS now, because previous handshake messages
 469          * are still missing, so just drop it.
 470          */
 471         if (!ssl_release_record(sc, rr, 0))
 472             return -1;
 473         goto start;
 474     }
 475
 476     /*
 477      * Unexpected handshake message (Client Hello, or protocol violation)
 478      */
 479     if (rr->type == SSL3_RT_HANDSHAKE && !ossl_statem_get_in_handshake(sc)) {
 480         struct hm_header_st msg_hdr;
 481
 482         /*
 483          * This may just be a stale retransmit. Also sanity check that we have
 484          * at least enough record bytes for a message header
 485          */
 486         if (rr->epoch != sc->rlayer.d->r_epoch
 487                 || rr->length < DTLS1_HM_HEADER_LENGTH) {
 488             if (!ssl_release_record(sc, rr, 0))
 489                 return -1;
 490             goto start;
 491         }
 492
 493         dtls1_get_message_header(rr->data, &msg_hdr);
 494
 495         /*
 496          * If we are server, we may have a repeated FINISHED of the client
 497          * here, then retransmit our CCS and FINISHED.
 498          */
 499         if (msg_hdr.type == SSL3_MT_FINISHED) {
 500             if (dtls1_check_timeout_num(sc) < 0) {
 501                 /* SSLfatal) already called */
 502                 return -1;
 503             }
 504
 505             if (dtls1_retransmit_buffered_messages(sc) <= 0) {
 506                 /* Fail if we encountered a fatal error */
 507                 if (ossl_statem_in_error(sc))
 508                     return -1;
 509             }
 510             if (!ssl_release_record(sc, rr, 0))
 511                 return -1;
 512             if (!(sc->mode & SSL_MODE_AUTO_RETRY)) {
 513                 if (!sc->rlayer.rrlmethod->unprocessed_read_pending(sc->rlayer.rrl)) {
 514                     /* no read-ahead left? */
 515                     BIO *bio;
 516
 517                     sc->rwstate = SSL_READING;
 518                     bio = SSL_get_rbio(s);
 519                     BIO_clear_retry_flags(bio);
 520                     BIO_set_retry_read(bio);
 521                     return -1;
 522                 }
 523             }
 524             goto start;
 525         }
 526
 527         /*
 528          * To get here we must be trying to read app data but found handshake
 529          * data. But if we're trying to read app data, and we're not in init
 530          * (which is tested for at the top of this function) then init must be
 531          * finished
 532          */
 533         if (!ossl_assert(SSL_is_init_finished(s))) {
 534             SSLfatal(sc, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 535             return -1;
 536         }
 537
 538         /* We found handshake data, so we're going back into init */
 539         ossl_statem_set_in_init(sc, 1);
 540
 541         i = sc->handshake_func(s);
 542         /* SSLfatal() called if appropriate */
 543         if (i < 0)
 544             return i;
 545         if (i == 0)
 546             return -1;
 547
 548         if (!(sc->mode & SSL_MODE_AUTO_RETRY)) {
 549             if (!sc->rlayer.rrlmethod->unprocessed_read_pending(sc->rlayer.rrl)) {
 550                 /* no read-ahead left? */
 551                 BIO *bio;
 552                 /*
 553                  * In the case where we try to read application data, but we
 554                  * trigger an SSL handshake, we return -1 with the retry
 555                  * option set.  Otherwise renegotiation may cause nasty
 556                  * problems in the blocking world
 557                  */
 558                 sc->rwstate = SSL_READING;
 559                 bio = SSL_get_rbio(s);
 560                 BIO_clear_retry_flags(bio);
 561                 BIO_set_retry_read(bio);
 562                 return -1;
 563             }
 564         }
 565         goto start;
 566     }
 567
 568     switch (rr->type) {
 569     default:
 570         SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE, SSL_R_UNEXPECTED_RECORD);
 571         return -1;
 572     case SSL3_RT_CHANGE_CIPHER_SPEC:
 573     case SSL3_RT_ALERT:
 574     case SSL3_RT_HANDSHAKE:
 575         /*
 576          * we already handled all of these, with the possible exception of
 577          * SSL3_RT_HANDSHAKE when ossl_statem_get_in_handshake(s) is true, but
 578          * that should not happen when type != rr->type
 579          */
 580         SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE, ERR_R_INTERNAL_ERROR);
 581         return -1;
 582     case SSL3_RT_APPLICATION_DATA:
 583         /*
 584          * At this point, we were expecting handshake data, but have
 585          * application data.  If the library was running inside ssl3_read()
 586          * (i.e. in_read_app_data is set) and it makes sense to read
 587          * application data at this point (session renegotiation not yet
 588          * started), we will indulge it.
 589          */
 590         if (sc->s3.in_read_app_data &&
 591             (sc->s3.total_renegotiations != 0) &&
 592             ossl_statem_app_data_allowed(sc)) {
 593             sc->s3.in_read_app_data = 2;
 594             return -1;
 595         } else {
 596             SSLfatal(sc, SSL_AD_UNEXPECTED_MESSAGE, SSL_R_UNEXPECTED_RECORD);
 597             return -1;
 598         }
 599     }
 600     /* not reached */
 601 }
 602
 603 /*
 604  * Call this to write data in records of type 'type' It will return <= 0 if
 605  * not all data has been sent or non-blocking IO.
 606  */
 607 int dtls1_write_bytes(SSL_CONNECTION *s, uint8_t type, const void *buf,
 608                       size_t len, size_t *written)
 609 {
 610     int i;
 611
 612     if (!ossl_assert(len <= SSL3_RT_MAX_PLAIN_LENGTH)) {
 613         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
 614         return -1;
 615     }
 616     s->rwstate = SSL_NOTHING;
 617     i = do_dtls1_write(s, type, buf, len, written);
 618     return i;
 619 }
 620
 621 int do_dtls1_write(SSL_CONNECTION *sc, uint8_t type, const unsigned char *buf,
 622                    size_t len, size_t *written)
 623 {
 624     int i;
 625     OSSL_RECORD_TEMPLATE tmpl;
 626     SSL *s = SSL_CONNECTION_GET_SSL(sc);
 627     int ret;
 628
 629     /* If we have an alert to send, lets send it */
 630     if (sc->s3.alert_dispatch > 0) {
 631         i = s->method->ssl_dispatch_alert(s);
 632         if (i <= 0)
 633             return i;
 634         /* if it went, fall through and send more stuff */
 635     }
 636
 637     if (len == 0)
 638         return 0;
 639
 640     if (len > ssl_get_max_send_fragment(sc)) {
 641         SSLfatal(sc, SSL_AD_INTERNAL_ERROR, SSL_R_EXCEEDS_MAX_FRAGMENT_SIZE);
 642         return 0;
 643     }
 644
 645     tmpl.type = type;
 646     /*
 647      * Special case: for hello verify request, client version 1.0 and we
 648      * haven't decided which version to use yet send back using version 1.0
 649      * header: otherwise some clients will ignore it.
 650      */
 651     if (s->method->version == DTLS_ANY_VERSION
 652             && sc->max_proto_version != DTLS1_BAD_VER)
 653         tmpl.version = DTLS1_VERSION;
 654     else
 655         tmpl.version = sc->version;
 656     tmpl.buf = buf;
 657     tmpl.buflen = len;
 658
 659     ret = HANDLE_RLAYER_WRITE_RETURN(sc,
 660               sc->rlayer.wrlmethod->write_records(sc->rlayer.wrl, &tmpl, 1));
 661
 662     if (ret > 0)
 663         *written = (int)len;
 664
 665     return ret;
 666 }
 667
 668 void dtls1_increment_epoch(SSL_CONNECTION *s, int rw)
 669 {
 670     if (rw & SSL3_CC_READ) {
 671         s->rlayer.d->r_epoch++;
 672
 673         /*
 674          * We must not use any buffered messages received from the previous
 675          * epoch
 676          */
 677         dtls1_clear_received_buffer(s);
 678     } else {
 679         s->rlayer.d->w_epoch++;
 680     }
 681 }
 682
 683 uint16_t dtls1_get_epoch(SSL_CONNECTION *s, int rw) {
 684     uint16_t epoch;
 685
 686     if (rw & SSL3_CC_READ)
 687         epoch = s->rlayer.d->r_epoch;
 688     else
 689         epoch = s->rlayer.d->w_epoch;
 690
 691     return epoch;
 692 }