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d1_lib.c

/* ssl/d1_lib.c */
/* 
 * DTLS implementation written by Nagendra Modadugu
 * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.  
 */
/* ====================================================================
 * Copyright (c) 1999-2005 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <stdio.h>
#define USE_SOCKETS
#include <openssl/objects.h>
#include "ssl_locl.h"

#if defined(OPENSSL_SYS_WIN32) || defined(OPENSSL_SYS_VMS)
#include <sys/timeb.h>
#endif

static void get_current_time(struct timeval *t);
const char dtls1_version_str[]="DTLSv1" OPENSSL_VERSION_PTEXT;
int dtls1_listen(SSL *s, struct sockaddr *client);

SSL3_ENC_METHOD DTLSv1_enc_data={
    dtls1_enc,
      tls1_mac,
      tls1_setup_key_block,
      tls1_generate_master_secret,
      tls1_change_cipher_state,
      tls1_final_finish_mac,
      TLS1_FINISH_MAC_LENGTH,
      tls1_cert_verify_mac,
      TLS_MD_CLIENT_FINISH_CONST,TLS_MD_CLIENT_FINISH_CONST_SIZE,
      TLS_MD_SERVER_FINISH_CONST,TLS_MD_SERVER_FINISH_CONST_SIZE,
      tls1_alert_code,
      };

long dtls1_default_timeout(void)
      {
      /* 2 hours, the 24 hours mentioned in the DTLSv1 spec
       * is way too long for http, the cache would over fill */
      return(60*60*2);
      }

IMPLEMENT_dtls1_meth_func(dtlsv1_base_method,
                  ssl_undefined_function,
                  ssl_undefined_function,
                  ssl_bad_method)

int dtls1_new(SSL *s)
      {
      DTLS1_STATE *d1;

      if (!ssl3_new(s)) return(0);
      if ((d1=OPENSSL_malloc(sizeof *d1)) == NULL) return (0);
      memset(d1,0, sizeof *d1);

      /* d1->handshake_epoch=0; */
#if defined(OPENSSL_SYS_VMS) || defined(VMS_TEST)
      d1->bitmap.length=64;
#else
      d1->bitmap.length=sizeof(d1->bitmap.map) * 8;
#endif
      pq_64bit_init(&(d1->bitmap.map));
      pq_64bit_init(&(d1->bitmap.max_seq_num));
      
      d1->next_bitmap.length = d1->bitmap.length;
      pq_64bit_init(&(d1->next_bitmap.map));
      pq_64bit_init(&(d1->next_bitmap.max_seq_num));

      d1->unprocessed_rcds.q=pqueue_new();
      d1->processed_rcds.q=pqueue_new();
      d1->buffered_messages = pqueue_new();
      d1->sent_messages=pqueue_new();
      d1->buffered_app_data.q=pqueue_new();

      if ( s->server)
            {
            d1->cookie_len = sizeof(s->d1->cookie);
            }

      if( ! d1->unprocessed_rcds.q || ! d1->processed_rcds.q 
        || ! d1->buffered_messages || ! d1->sent_messages || ! d1->buffered_app_data.q)
            {
        if ( d1->unprocessed_rcds.q) pqueue_free(d1->unprocessed_rcds.q);
        if ( d1->processed_rcds.q) pqueue_free(d1->processed_rcds.q);
        if ( d1->buffered_messages) pqueue_free(d1->buffered_messages);
            if ( d1->sent_messages) pqueue_free(d1->sent_messages);
            if ( d1->buffered_app_data.q) pqueue_free(d1->buffered_app_data.q);
            OPENSSL_free(d1);
            return (0);
            }

      s->d1=d1;
      s->method->ssl_clear(s);
      return(1);
      }

void dtls1_free(SSL *s)
      {
    pitem *item = NULL;
    hm_fragment *frag = NULL;

      ssl3_free(s);

    while( (item = pqueue_pop(s->d1->unprocessed_rcds.q)) != NULL)
        {
        OPENSSL_free(item->data);
        pitem_free(item);
        }
    pqueue_free(s->d1->unprocessed_rcds.q);

    while( (item = pqueue_pop(s->d1->processed_rcds.q)) != NULL)
        {
        OPENSSL_free(item->data);
        pitem_free(item);
        }
    pqueue_free(s->d1->processed_rcds.q);

    while( (item = pqueue_pop(s->d1->buffered_messages)) != NULL)
        {
        frag = (hm_fragment *)item->data;
        OPENSSL_free(frag->fragment);
        OPENSSL_free(frag);
        pitem_free(item);
        }
    pqueue_free(s->d1->buffered_messages);

    while ( (item = pqueue_pop(s->d1->sent_messages)) != NULL)
        {
        frag = (hm_fragment *)item->data;
        OPENSSL_free(frag->fragment);
        OPENSSL_free(frag);
        pitem_free(item);
        }
      pqueue_free(s->d1->sent_messages);

      while ( (item = pqueue_pop(s->d1->buffered_app_data.q)) != NULL)
      {
            frag = (hm_fragment *)item->data;
            OPENSSL_free(frag->fragment);
            OPENSSL_free(frag);
            pitem_free(item);
      }
      pqueue_free(s->d1->buffered_app_data.q);
      
      pq_64bit_free(&(s->d1->bitmap.map));
      pq_64bit_free(&(s->d1->bitmap.max_seq_num));

      pq_64bit_free(&(s->d1->next_bitmap.map));
      pq_64bit_free(&(s->d1->next_bitmap.max_seq_num));

      OPENSSL_free(s->d1);
      }

void dtls1_clear(SSL *s)
      {
      ssl3_clear(s);
      if (s->options & SSL_OP_CISCO_ANYCONNECT)
            s->version=DTLS1_BAD_VER;
      else
            s->version=DTLS1_VERSION;
      }

long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
      {
      int ret=0;

      switch (cmd)
            {
      case DTLS_CTRL_GET_TIMEOUT:
            if (dtls1_get_timeout(s, (struct timeval*) parg) != NULL)
                  {
                  ret = 1;
                  }
            break;
      case DTLS_CTRL_HANDLE_TIMEOUT:
            ret = dtls1_handle_timeout(s);
            break;
      case DTLS_CTRL_LISTEN:
            ret = dtls1_listen(s, parg);
            break;

      default:
            ret = ssl3_ctrl(s, cmd, larg, parg);
            break;
            }
      return(ret);
      }

/*
 * As it's impossible to use stream ciphers in "datagram" mode, this
 * simple filter is designed to disengage them in DTLS. Unfortunately
 * there is no universal way to identify stream SSL_CIPHER, so we have
 * to explicitly list their SSL_* codes. Currently RC4 is the only one
 * available, but if new ones emerge, they will have to be added...
 */
SSL_CIPHER *dtls1_get_cipher(unsigned int u)
      {
      SSL_CIPHER *ciph = ssl3_get_cipher(u);

      if (ciph != NULL)
            {
            if ((ciph->algorithms&SSL_ENC_MASK) == SSL_RC4)
                  return NULL;
            }

      return ciph;
      }

void dtls1_start_timer(SSL *s)
      {
      /* If timer is not set, initialize duration with 1 second */
      if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0)
            {
            s->d1->timeout_duration = 1;
            }
      
      /* Set timeout to current time */
      get_current_time(&(s->d1->next_timeout));

      /* Add duration to current time */
      s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
      BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &(s->d1->next_timeout));
      }

struct timeval* dtls1_get_timeout(SSL *s, struct timeval* timeleft)
      {
      struct timeval timenow;

      /* If no timeout is set, just return NULL */
      if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0)
            {
            return NULL;
            }

      /* Get current time */
      get_current_time(&timenow);

      /* If timer already expired, set remaining time to 0 */
      if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
            (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
             s->d1->next_timeout.tv_usec <= timenow.tv_usec))
            {
            memset(timeleft, 0, sizeof(struct timeval));
            return timeleft;
            }

      /* Calculate time left until timer expires */
      memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
      timeleft->tv_sec -= timenow.tv_sec;
      timeleft->tv_usec -= timenow.tv_usec;
      if (timeleft->tv_usec < 0)
            {
            timeleft->tv_sec--;
            timeleft->tv_usec += 1000000;
            }

      /* If remaining time is less than 15 ms, set it to 0
       * to prevent issues because of small devergences with
       * socket timeouts.
       */
      if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000)
            {
            memset(timeleft, 0, sizeof(struct timeval));
            }
      

      return timeleft;
      }

int dtls1_is_timer_expired(SSL *s)
      {
      struct timeval timeleft;

      /* Get time left until timeout, return false if no timer running */
      if (dtls1_get_timeout(s, &timeleft) == NULL)
            {
            return 0;
            }

      /* Return false if timer is not expired yet */
      if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0)
            {
            return 0;
            }

      /* Timer expired, so return true */ 
      return 1;
      }

void dtls1_double_timeout(SSL *s)
      {
      s->d1->timeout_duration *= 2;
      if (s->d1->timeout_duration > 60)
            s->d1->timeout_duration = 60;
      dtls1_start_timer(s);
      }

void dtls1_stop_timer(SSL *s)
      {
      /* Reset everything */
      memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
      s->d1->timeout_duration = 1;
      BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &(s->d1->next_timeout));
      }

int dtls1_handle_timeout(SSL *s)
      {
      DTLS1_STATE *state;

      /* if no timer is expired, don't do anything */
      if (!dtls1_is_timer_expired(s))
            {
            return 0;
            }

      dtls1_double_timeout(s);
      state = s->d1;
      state->timeout.num_alerts++;
      if ( state->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT)
            {
            /* fail the connection, enough alerts have been sent */
            SSLerr(SSL_F_DTLS1_HANDLE_TIMEOUT,SSL_R_READ_TIMEOUT_EXPIRED);
            return 0;
            }

      state->timeout.read_timeouts++;
      if ( state->timeout.read_timeouts > DTLS1_TMO_READ_COUNT)
            {
            state->timeout.read_timeouts = 1;
            }

      dtls1_start_timer(s);
      return dtls1_retransmit_buffered_messages(s);
      }

static void get_current_time(struct timeval *t)
{
#ifdef OPENSSL_SYS_WIN32
      struct _timeb tb;
      _ftime(&tb);
      t->tv_sec = (long)tb.time;
      t->tv_usec = (long)tb.millitm * 1000;
#elif defined(OPENSSL_SYS_VMS)
      struct timeb tb;
      ftime(&tb);
      t->tv_sec = (long)tb.time;
      t->tv_usec = (long)tb.millitm * 1000;
#else
      gettimeofday(t, NULL);
#endif
}

int dtls1_listen(SSL *s, struct sockaddr *client)
      {
      int ret;

      SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
      s->d1->listen = 1;

      ret = SSL_accept(s);
      if (ret <= 0) return ret;
      
      (void) BIO_dgram_get_peer(SSL_get_rbio(s), client);
      return 1;
      }

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