/*

 * 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 <openssl/ssl.h>

#include <assert.h>

#include <limits.h>

#include <string.h>

#include <openssl/err.h>

#include <openssl/mem.h>

#include <openssl/nid.h>

#include "../crypto/internal.h"

#include "internal.h"

BSSL_NAMESPACE_BEGIN

// DTLS1_MTU_TIMEOUTS is the maximum number of timeouts to expire

// before starting to decrease the MTU.

#define DTLS1_MTU_TIMEOUTS                     2

// DTLS1_MAX_TIMEOUTS is the maximum number of timeouts to expire

// before failing the DTLS handshake.

#define DTLS1_MAX_TIMEOUTS                     12

DTLS1_STATE::DTLS1_STATE()

    : has_change_cipher_spec(false),

      outgoing_messages_complete(false),

      flight_has_reply(false) {}

DTLS1_STATE::~DTLS1_STATE() {}

bool dtls1_new(SSL *ssl) {

  if (!tls_new(ssl)) {

    return false;

  }

  UniquePtr<DTLS1_STATE> d1 = MakeUnique<DTLS1_STATE>();

  if (!d1) {

    tls_free(ssl);

    return false;

  }

  ssl->d1 = d1.release();

  // Set the version to the highest supported version.

  //

  // TODO(davidben): Move this field into |s3|, have it store the normalized

  // protocol version, and implement this pre-negotiation quirk in |SSL_version|

  // at the API boundary rather than in internal state.

  ssl->version = DTLS1_2_VERSION;

  return true;

}

void dtls1_free(SSL *ssl) {

  tls_free(ssl);

  if (ssl == NULL) {

    return;

  }

  Delete(ssl->d1);

  ssl->d1 = NULL;

}

void dtls1_start_timer(SSL *ssl) {

  // If timer is not set, initialize duration (by default, 1 second)

  if (ssl->d1->next_timeout.tv_sec == 0 && ssl->d1->next_timeout.tv_usec == 0) {

    ssl->d1->timeout_duration_ms = ssl->initial_timeout_duration_ms;

  }

  // Set timeout to current time

  ssl_get_current_time(ssl, &ssl->d1->next_timeout);

  // Add duration to current time

  ssl->d1->next_timeout.tv_sec += ssl->d1->timeout_duration_ms / 1000;

  ssl->d1->next_timeout.tv_usec += (ssl->d1->timeout_duration_ms % 1000) * 1000;

  if (ssl->d1->next_timeout.tv_usec >= 1000000) {

    ssl->d1->next_timeout.tv_sec++;

    ssl->d1->next_timeout.tv_usec -= 1000000;

  }

}

bool dtls1_is_timer_expired(SSL *ssl) {

  struct timeval timeleft;

  // Get time left until timeout, return false if no timer running

  if (!DTLSv1_get_timeout(ssl, &timeleft)) {

    return false;

  }

  // Return false if timer is not expired yet

  if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {

    return false;

  }

  // Timer expired, so return true

  return true;

}

static void dtls1_double_timeout(SSL *ssl) {

  ssl->d1->timeout_duration_ms *= 2;

  if (ssl->d1->timeout_duration_ms > 60000) {

    ssl->d1->timeout_duration_ms = 60000;

  }

}

void dtls1_stop_timer(SSL *ssl) {

  ssl->d1->num_timeouts = 0;

  OPENSSL_memset(&ssl->d1->next_timeout, 0, sizeof(ssl->d1->next_timeout));

  ssl->d1->timeout_duration_ms = ssl->initial_timeout_duration_ms;

}

bool dtls1_check_timeout_num(SSL *ssl) {

  ssl->d1->num_timeouts++;

  // Reduce MTU after 2 unsuccessful retransmissions

  if (ssl->d1->num_timeouts > DTLS1_MTU_TIMEOUTS &&

      !(SSL_get_options(ssl) & SSL_OP_NO_QUERY_MTU)) {

    long mtu =

        BIO_ctrl(ssl->wbio.get(), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, nullptr);

    if (mtu >= 0 && mtu <= (1 << 30) && (unsigned)mtu >= dtls1_min_mtu()) {

      ssl->d1->mtu = (unsigned)mtu;

    }

  }

  if (ssl->d1->num_timeouts > DTLS1_MAX_TIMEOUTS) {

    // fail the connection, enough alerts have been sent

    OPENSSL_PUT_ERROR(SSL, SSL_R_READ_TIMEOUT_EXPIRED);

    return false;

  }

  return true;

}

BSSL_NAMESPACE_END

using namespace bssl;

void DTLSv1_set_initial_timeout_duration(SSL *ssl, unsigned int duration_ms) {

  ssl->initial_timeout_duration_ms = duration_ms;

}

int DTLSv1_get_timeout(const SSL *ssl, struct timeval *out) {

  if (!SSL_is_dtls(ssl)) {

    return 0;

  }

  // If no timeout is set, just return 0.

  if (ssl->d1->next_timeout.tv_sec == 0 && ssl->d1->next_timeout.tv_usec == 0) {

    return 0;

  }

  struct OPENSSL_timeval timenow;

  ssl_get_current_time(ssl, &timenow);

  // If timer already expired, set remaining time to 0.

  if (ssl->d1->next_timeout.tv_sec < timenow.tv_sec ||

      (ssl->d1->next_timeout.tv_sec == timenow.tv_sec &&

       ssl->d1->next_timeout.tv_usec <= timenow.tv_usec)) {

    OPENSSL_memset(out, 0, sizeof(*out));

    return 1;

  }

  // Calculate time left until timer expires.

  struct OPENSSL_timeval ret;

  OPENSSL_memcpy(&ret, &ssl->d1->next_timeout, sizeof(ret));

  ret.tv_sec -= timenow.tv_sec;

  if (ret.tv_usec >= timenow.tv_usec) {

    ret.tv_usec -= timenow.tv_usec;

  } else {

    ret.tv_usec = 1000000 + ret.tv_usec - timenow.tv_usec;

    ret.tv_sec--;

  }

  // If remaining time is less than 15 ms, set it to 0 to prevent issues

  // because of small divergences with socket timeouts.

  if (ret.tv_sec == 0 && ret.tv_usec < 15000) {

    OPENSSL_memset(&ret, 0, sizeof(ret));

  }

  // Clamp the result in case of overflow.

  if (ret.tv_sec > INT_MAX) {

    assert(0);

    out->tv_sec = INT_MAX;

  } else {

    out->tv_sec = ret.tv_sec;

  }

  out->tv_usec = ret.tv_usec;

  return 1;

}

int DTLSv1_handle_timeout(SSL *ssl) {

  ssl_reset_error_state(ssl);

  if (!SSL_is_dtls(ssl)) {

    OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);

    return -1;

  }

  // If no timer is expired, don't do anything.

  if (!dtls1_is_timer_expired(ssl)) {

    return 0;

  }

  if (!dtls1_check_timeout_num(ssl)) {

    return -1;

  }

  dtls1_double_timeout(ssl);

  dtls1_start_timer(ssl);

  return dtls1_retransmit_outgoing_messages(ssl);

}