ssl/ssl_lib.cc

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * 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 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 acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS 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 AUTHOR OR 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.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */
/* ====================================================================
 * Copyright (c) 1998-2007 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).
 *
 */
/* ====================================================================
 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
 * ECC cipher suite support in OpenSSL originally developed by
 * SUN MICROSYSTEMS, INC., and contributed to the OpenSSL project.
 */
/* ====================================================================
 * Copyright 2005 Nokia. All rights reserved.
 *
 * The portions of the attached software ("Contribution") is developed by
 * Nokia Corporation and is licensed pursuant to the OpenSSL open source
 * license.
 *
 * The Contribution, originally written by Mika Kousa and Pasi Eronen of
 * Nokia Corporation, consists of the "PSK" (Pre-Shared Key) ciphersuites
 * support (see RFC 4279) to OpenSSL.
 *
 * No patent licenses or other rights except those expressly stated in
 * the OpenSSL open source license shall be deemed granted or received
 * expressly, by implication, estoppel, or otherwise.
 *
 * No assurances are provided by Nokia that the Contribution does not
 * infringe the patent or other intellectual property rights of any third
 * party or that the license provides you with all the necessary rights
 * to make use of the Contribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. IN
 * ADDITION TO THE DISCLAIMERS INCLUDED IN THE LICENSE, NOKIA
 * SPECIFICALLY DISCLAIMS ANY LIABILITY FOR CLAIMS BROUGHT BY YOU OR ANY
 * OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OR
 * OTHERWISE. */

#include <openssl/ssl.h>

#include <assert.h>
#include <stdlib.h>
#include <string.h>

#include <openssl/bytestring.h>
#include <openssl/crypto.h>
#include <openssl/err.h>
#include <openssl/lhash.h>
#include <openssl/mem.h>
#include <openssl/rand.h>

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

#if defined(OPENSSL_WINDOWS)
#include <sys/timeb.h>
#else
#include <sys/socket.h>
#include <sys/time.h>
#endif


namespace bssl {

// |SSL_R_UNKNOWN_PROTOCOL| is no longer emitted, but continue to define it
// to avoid downstream churn.
OPENSSL_DECLARE_ERROR_REASON(SSL, UNKNOWN_PROTOCOL)

// The following errors are no longer emitted, but are used in nginx without
// #ifdefs.
OPENSSL_DECLARE_ERROR_REASON(SSL, BLOCK_CIPHER_PAD_IS_WRONG)
OPENSSL_DECLARE_ERROR_REASON(SSL, NO_CIPHERS_SPECIFIED)

// Some error codes are special. Ensure the make_errors.go script never
// regresses this.
static_assert(SSL_R_TLSV1_ALERT_NO_RENEGOTIATION ==
                  SSL_AD_NO_RENEGOTIATION + SSL_AD_REASON_OFFSET,
              "alert reason code mismatch");

// kMaxHandshakeSize is the maximum size, in bytes, of a handshake message.
static const size_t kMaxHandshakeSize = (1u << 24) - 1;

static CRYPTO_EX_DATA_CLASS g_ex_data_class_ssl =
    CRYPTO_EX_DATA_CLASS_INIT_WITH_APP_DATA;
static CRYPTO_EX_DATA_CLASS g_ex_data_class_ssl_ctx =
    CRYPTO_EX_DATA_CLASS_INIT_WITH_APP_DATA;

bool CBBFinishArray(CBB *cbb, Array<uint8_t> *out) {
  uint8_t *ptr;
  size_t len;
  if (!CBB_finish(cbb, &ptr, &len)) {
    OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
    return false;
  }
  out->Reset(ptr, len);
  return true;
}

void ssl_reset_error_state(SSL *ssl) {
  // Functions which use |SSL_get_error| must reset I/O and error state on
  // entry.
  ssl->s3->rwstate = SSL_NOTHING;
  ERR_clear_error();
  ERR_clear_system_error();
}

void ssl_set_read_error(SSL* ssl) {
  ssl->s3->read_shutdown = ssl_shutdown_error;
  ssl->s3->read_error.reset(ERR_save_state());
}

static bool check_read_error(const SSL *ssl) {
  if (ssl->s3->read_shutdown == ssl_shutdown_error) {
    ERR_restore_state(ssl->s3->read_error.get());
    return false;
  }
  return true;
}

int ssl_can_write(const SSL *ssl) {
  return !SSL_in_init(ssl) || ssl->s3->hs->can_early_write;
}

int ssl_can_read(const SSL *ssl) {
  return !SSL_in_init(ssl) || ssl->s3->hs->can_early_read;
}

ssl_open_record_t ssl_open_handshake(SSL *ssl, size_t *out_consumed,
                                     uint8_t *out_alert, Span<uint8_t> in) {
  *out_consumed = 0;
  if (!check_read_error(ssl)) {
    *out_alert = 0;
    return ssl_open_record_error;
  }
  auto ret = ssl->method->open_handshake(ssl, out_consumed, out_alert, in);
  if (ret == ssl_open_record_error) {
    ssl_set_read_error(ssl);
  }
  return ret;
}

ssl_open_record_t ssl_open_change_cipher_spec(SSL *ssl, size_t *out_consumed,
                                              uint8_t *out_alert,
                                              Span<uint8_t> in) {
  *out_consumed = 0;
  if (!check_read_error(ssl)) {
    *out_alert = 0;
    return ssl_open_record_error;
  }
  auto ret =
      ssl->method->open_change_cipher_spec(ssl, out_consumed, out_alert, in);
  if (ret == ssl_open_record_error) {
    ssl_set_read_error(ssl);
  }
  return ret;
}

ssl_open_record_t ssl_open_app_data(SSL *ssl, Span<uint8_t> *out,
                                    size_t *out_consumed, uint8_t *out_alert,
                                    Span<uint8_t> in) {
  *out_consumed = 0;
  if (!check_read_error(ssl)) {
    *out_alert = 0;
    return ssl_open_record_error;
  }
  auto ret = ssl->method->open_app_data(ssl, out, out_consumed, out_alert, in);
  if (ret == ssl_open_record_error) {
    ssl_set_read_error(ssl);
  }
  return ret;
}

void ssl_update_cache(SSL_HANDSHAKE *hs, int mode) {
  SSL *const ssl = hs->ssl;
  SSL_CTX *ctx = ssl->session_ctx;
  // Never cache sessions with empty session IDs.
  if (ssl->s3->established_session->session_id_length == 0 ||
      ssl->s3->established_session->not_resumable ||
      (ctx->session_cache_mode & mode) != mode) {
    return;
  }

  // Clients never use the internal session cache.
  int use_internal_cache = ssl->server && !(ctx->session_cache_mode &
                                            SSL_SESS_CACHE_NO_INTERNAL_STORE);

  // A client may see new sessions on abbreviated handshakes if the server
  // decides to renew the ticket. Once the handshake is completed, it should be
  // inserted into the cache.
  if (ssl->s3->established_session.get() != ssl->session ||
      (!ssl->server && hs->ticket_expected)) {
    if (use_internal_cache) {
      SSL_CTX_add_session(ctx, ssl->s3->established_session.get());
    }
    if (ctx->new_session_cb != NULL) {
      SSL_SESSION_up_ref(ssl->s3->established_session.get());
      if (!ctx->new_session_cb(ssl, ssl->s3->established_session.get())) {
        // |new_session_cb|'s return value signals whether it took ownership.
        SSL_SESSION_free(ssl->s3->established_session.get());
      }
    }
  }

  if (use_internal_cache &&
      !(ctx->session_cache_mode & SSL_SESS_CACHE_NO_AUTO_CLEAR)) {
    // Automatically flush the internal session cache every 255 connections.
    int flush_cache = 0;
    CRYPTO_MUTEX_lock_write(&ctx->lock);
    ctx->handshakes_since_cache_flush++;
    if (ctx->handshakes_since_cache_flush >= 255) {
      flush_cache = 1;
      ctx->handshakes_since_cache_flush = 0;
    }
    CRYPTO_MUTEX_unlock_write(&ctx->lock);

    if (flush_cache) {
      struct OPENSSL_timeval now;
      ssl_get_current_time(ssl, &now);
      SSL_CTX_flush_sessions(ctx, now.tv_sec);
    }
  }
}

static int cbb_add_hex(CBB *cbb, const uint8_t *in, size_t in_len) {
  static const char hextable[] = "0123456789abcdef";
  uint8_t *out;

  if (!CBB_add_space(cbb, &out, in_len * 2)) {
    return 0;
  }

  for (size_t i = 0; i < in_len; i++) {
    *(out++) = (uint8_t)hextable[in[i] >> 4];
    *(out++) = (uint8_t)hextable[in[i] & 0xf];
  }

  return 1;
}

int ssl_log_secret(const SSL *ssl, const char *label, const uint8_t *secret,
                   size_t secret_len) {
  if (ssl->ctx->keylog_callback == NULL) {
    return 1;
  }

  ScopedCBB cbb;
  uint8_t *out;
  size_t out_len;
  if (!CBB_init(cbb.get(), strlen(label) + 1 + SSL3_RANDOM_SIZE * 2 + 1 +
                          secret_len * 2 + 1) ||
      !CBB_add_bytes(cbb.get(), (const uint8_t *)label, strlen(label)) ||
      !CBB_add_bytes(cbb.get(), (const uint8_t *)" ", 1) ||
      !cbb_add_hex(cbb.get(), ssl->s3->client_random, SSL3_RANDOM_SIZE) ||
      !CBB_add_bytes(cbb.get(), (const uint8_t *)" ", 1) ||
      !cbb_add_hex(cbb.get(), secret, secret_len) ||
      !CBB_add_u8(cbb.get(), 0 /* NUL */) ||
      !CBB_finish(cbb.get(), &out, &out_len)) {
    return 0;
  }

  ssl->ctx->keylog_callback(ssl, (const char *)out);
  OPENSSL_free(out);
  return 1;
}

void ssl_do_info_callback(const SSL *ssl, int type, int value) {
  void (*cb)(const SSL *ssl, int type, int value) = NULL;
  if (ssl->info_callback != NULL) {
    cb = ssl->info_callback;
  } else if (ssl->ctx->info_callback != NULL) {
    cb = ssl->ctx->info_callback;
  }

  if (cb != NULL) {
    cb(ssl, type, value);
  }
}

void ssl_do_msg_callback(SSL *ssl, int is_write, int content_type,
                         Span<const uint8_t> in) {
  if (ssl->msg_callback == NULL) {
    return;
  }

  // |version| is zero when calling for |SSL3_RT_HEADER| and |SSL2_VERSION| for
  // a V2ClientHello.
  int version;
  switch (content_type) {
    case 0:
      // V2ClientHello
      version = SSL2_VERSION;
      break;
    case SSL3_RT_HEADER:
      version = 0;
      break;
    default:
      version = SSL_version(ssl);
  }

  ssl->msg_callback(is_write, version, content_type, in.data(), in.size(), ssl,
                    ssl->msg_callback_arg);
}

void ssl_get_current_time(const SSL *ssl, struct OPENSSL_timeval *out_clock) {
  // TODO(martinkr): Change callers to |ssl_ctx_get_current_time| and drop the
  // |ssl| arg from |current_time_cb| if possible.
  ssl_ctx_get_current_time(ssl->ctx, out_clock);
}

void ssl_ctx_get_current_time(const SSL_CTX *ctx,
                              struct OPENSSL_timeval *out_clock) {
  if (ctx->current_time_cb != NULL) {
    // TODO(davidben): Update current_time_cb to use OPENSSL_timeval. See
    // https://crbug.com/boringssl/155.
    struct timeval clock;
    ctx->current_time_cb(nullptr /* ssl */, &clock);
    if (clock.tv_sec < 0) {
      assert(0);
      out_clock->tv_sec = 0;
      out_clock->tv_usec = 0;
    } else {
      out_clock->tv_sec = (uint64_t)clock.tv_sec;
      out_clock->tv_usec = (uint32_t)clock.tv_usec;
    }
    return;
  }

#if defined(BORINGSSL_UNSAFE_DETERMINISTIC_MODE)
  out_clock->tv_sec = 1234;
  out_clock->tv_usec = 1234;
#elif defined(OPENSSL_WINDOWS)
  struct _timeb time;
  _ftime(&time);
  if (time.time < 0) {
    assert(0);
    out_clock->tv_sec = 0;
    out_clock->tv_usec = 0;
  } else {
    out_clock->tv_sec = time.time;
    out_clock->tv_usec = time.millitm * 1000;
  }
#else
  struct timeval clock;
  gettimeofday(&clock, NULL);
  if (clock.tv_sec < 0) {
    assert(0);
    out_clock->tv_sec = 0;
    out_clock->tv_usec = 0;
  } else {
    out_clock->tv_sec = (uint64_t)clock.tv_sec;
    out_clock->tv_usec = (uint32_t)clock.tv_usec;
  }
#endif
}

void SSL_CTX_set_handoff_mode(SSL_CTX *ctx, bool on) {
  ctx->handoff = on;
}

static bool ssl_can_renegotiate(const SSL *ssl) {
  if (ssl->server || SSL_is_dtls(ssl)) {
    return false;
  }

  // We do not accept at SSL 3.0. SSL 3.0 will be removed entirely in the future
  // and requires retaining more data for renegotiation_info.
  uint16_t version = ssl_protocol_version(ssl);
  if (version == SSL3_VERSION || version >= TLS1_3_VERSION) {
    return false;
  }

  // The config has already been shed.
  if (!ssl->config) {
    return false;
  }

  switch (ssl->renegotiate_mode) {
    case ssl_renegotiate_ignore:
    case ssl_renegotiate_never:
      return false;

    case ssl_renegotiate_freely:
      return true;
    case ssl_renegotiate_once:
      return ssl->s3->total_renegotiations == 0;
  }

  assert(0);
  return false;
}

static void ssl_maybe_shed_handshake_config(SSL *ssl) {
  if (ssl->s3->hs != nullptr ||
      ssl->config == nullptr ||
      !ssl->config->shed_handshake_config ||
      ssl_can_renegotiate(ssl)) {
    return;
  }

  Delete(ssl->config);
  ssl->config = nullptr;
}

void SSL_set_handoff_mode(SSL *ssl, bool on) {
  if (!ssl->config) {
    return;
  }
  ssl->config->handoff = on;
}

}  // namespace bssl

using namespace bssl;

int SSL_library_init(void) {
  CRYPTO_library_init();
  return 1;
}

int OPENSSL_init_ssl(uint64_t opts, const OPENSSL_INIT_SETTINGS *settings) {
  CRYPTO_library_init();
  return 1;
}

static uint32_t ssl_session_hash(const SSL_SESSION *sess) {
  const uint8_t *session_id = sess->session_id;

  uint8_t tmp_storage[sizeof(uint32_t)];
  if (sess->session_id_length < sizeof(tmp_storage)) {
    OPENSSL_memset(tmp_storage, 0, sizeof(tmp_storage));
    OPENSSL_memcpy(tmp_storage, sess->session_id, sess->session_id_length);
    session_id = tmp_storage;
  }

  uint32_t hash =
      ((uint32_t)session_id[0]) |
      ((uint32_t)session_id[1] << 8) |
      ((uint32_t)session_id[2] << 16) |
      ((uint32_t)session_id[3] << 24);

  return hash;
}

// NB: If this function (or indeed the hash function which uses a sort of
// coarser function than this one) is changed, ensure
// SSL_CTX_has_matching_session_id() is checked accordingly. It relies on being
// able to construct an SSL_SESSION that will collide with any existing session
// with a matching session ID.
static int ssl_session_cmp(const SSL_SESSION *a, const SSL_SESSION *b) {
  if (a->ssl_version != b->ssl_version) {
    return 1;
  }

  if (a->session_id_length != b->session_id_length) {
    return 1;
  }

  return OPENSSL_memcmp(a->session_id, b->session_id, a->session_id_length);
}

SSL_CTX *SSL_CTX_new(const SSL_METHOD *method) {
  SSL_CTX *ret = NULL;

  if (method == NULL) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_NULL_SSL_METHOD_PASSED);
    return NULL;
  }

  ret = (SSL_CTX *)OPENSSL_malloc(sizeof(SSL_CTX));
  if (ret == NULL) {
    goto err;
  }

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

  ret->method = method->method;
  ret->x509_method = method->x509_method;

  CRYPTO_MUTEX_init(&ret->lock);

  ret->session_cache_mode = SSL_SESS_CACHE_SERVER;
  ret->session_cache_size = SSL_SESSION_CACHE_MAX_SIZE_DEFAULT;

  ret->session_timeout = SSL_DEFAULT_SESSION_TIMEOUT;
  ret->session_psk_dhe_timeout = SSL_DEFAULT_SESSION_PSK_DHE_TIMEOUT;

  ret->references = 1;

  ret->max_cert_list = SSL_MAX_CERT_LIST_DEFAULT;
  ret->verify_mode = SSL_VERIFY_NONE;
  ret->cert = New<CERT>(method->x509_method);
  if (ret->cert == NULL) {
    goto err;
  }

  ret->sessions = lh_SSL_SESSION_new(ssl_session_hash, ssl_session_cmp);
  if (ret->sessions == NULL) {
    goto err;
  }

  if (!ret->x509_method->ssl_ctx_new(ret)) {
    goto err;
  }

  if (!SSL_CTX_set_strict_cipher_list(ret, SSL_DEFAULT_CIPHER_LIST)) {
    goto err2;
  }

  ret->client_CA = sk_CRYPTO_BUFFER_new_null();
  if (ret->client_CA == NULL) {
    goto err;
  }

  CRYPTO_new_ex_data(&ret->ex_data);

  ret->max_send_fragment = SSL3_RT_MAX_PLAIN_LENGTH;

  // Disable the auto-chaining feature by default. Once this has stuck without
  // problems, the feature will be removed entirely.
  ret->mode = SSL_MODE_NO_AUTO_CHAIN;

  ret->rsa_pss_rsae_certs_enabled = true;

  // Lock the SSL_CTX to the specified version, for compatibility with legacy
  // uses of SSL_METHOD.
  if (!SSL_CTX_set_max_proto_version(ret, method->version) ||
      !SSL_CTX_set_min_proto_version(ret, method->version)) {
    OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
    goto err2;
  }

  return ret;

err:
  OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
err2:
  SSL_CTX_free(ret);
  return NULL;
}

int SSL_CTX_up_ref(SSL_CTX *ctx) {
  CRYPTO_refcount_inc(&ctx->references);
  return 1;
}

void SSL_CTX_free(SSL_CTX *ctx) {
  if (ctx == NULL ||
      !CRYPTO_refcount_dec_and_test_zero(&ctx->references)) {
    return;
  }

  // Free internal session cache. However: the remove_cb() may reference the
  // ex_data of SSL_CTX, thus the ex_data store can only be removed after the
  // sessions were flushed. As the ex_data handling routines might also touch
  // the session cache, the most secure solution seems to be: empty (flush) the
  // cache, then free ex_data, then finally free the cache. (See ticket
  // [openssl.org #212].)
  SSL_CTX_flush_sessions(ctx, 0);

  CRYPTO_free_ex_data(&g_ex_data_class_ssl_ctx, ctx, &ctx->ex_data);

  CRYPTO_MUTEX_cleanup(&ctx->lock);
  lh_SSL_SESSION_free(ctx->sessions);
  Delete(ctx->cipher_list);
  Delete(ctx->cert);
  sk_SSL_CUSTOM_EXTENSION_pop_free(ctx->client_custom_extensions,
                                   SSL_CUSTOM_EXTENSION_free);
  sk_SSL_CUSTOM_EXTENSION_pop_free(ctx->server_custom_extensions,
                                   SSL_CUSTOM_EXTENSION_free);
  sk_CRYPTO_BUFFER_pop_free(ctx->client_CA, CRYPTO_BUFFER_free);
  ctx->x509_method->ssl_ctx_free(ctx);
  sk_SRTP_PROTECTION_PROFILE_free(ctx->srtp_profiles);
  OPENSSL_free(ctx->psk_identity_hint);
  OPENSSL_free(ctx->supported_group_list);
  OPENSSL_free(ctx->alpn_client_proto_list);
  EVP_PKEY_free(ctx->tlsext_channel_id_private);
  OPENSSL_free(ctx->verify_sigalgs);
  OPENSSL_free(ctx->tlsext_ticket_key_current);
  OPENSSL_free(ctx->tlsext_ticket_key_prev);

  OPENSSL_free(ctx);
}

SSL *SSL_new(SSL_CTX *ctx) {
  if (ctx == NULL) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_NULL_SSL_CTX);
    return NULL;
  }
  if (ctx->method == NULL) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_SSL_CTX_HAS_NO_DEFAULT_SSL_VERSION);
    return NULL;
  }

  SSL *ssl = (SSL *)OPENSSL_malloc(sizeof(SSL));
  if (ssl == NULL) {
    goto err;
  }
  OPENSSL_memset(ssl, 0, sizeof(SSL));

  ssl->config = New<SSL_CONFIG>(ssl);
  if (ssl->config == nullptr) {
    goto err;
  }
  ssl->config->conf_min_version = ctx->conf_min_version;
  ssl->config->conf_max_version = ctx->conf_max_version;
  ssl->tls13_variant = ctx->tls13_variant;

  // RFC 6347 states that implementations SHOULD use an initial timer value of
  // 1 second.
  ssl->initial_timeout_duration_ms = 1000;

  ssl->options = ctx->options;
  ssl->mode = ctx->mode;
  ssl->max_cert_list = ctx->max_cert_list;

  ssl->config->cert = ssl_cert_dup(ctx->cert).release();
  if (ssl->config->cert == NULL) {
    goto err;
  }

  ssl->msg_callback = ctx->msg_callback;
  ssl->msg_callback_arg = ctx->msg_callback_arg;
  ssl->config->verify_mode = ctx->verify_mode;
  ssl->config->verify_callback = ctx->default_verify_callback;
  ssl->config->custom_verify_callback = ctx->custom_verify_callback;
  ssl->config->retain_only_sha256_of_client_certs =
      ctx->retain_only_sha256_of_client_certs;

  ssl->quiet_shutdown = ctx->quiet_shutdown;
  ssl->max_send_fragment = ctx->max_send_fragment;
  ssl->enable_early_data = ctx->enable_early_data;

  SSL_CTX_up_ref(ctx);
  ssl->ctx = ctx;
  SSL_CTX_up_ref(ctx);
  ssl->session_ctx = ctx;

  if (ctx->supported_group_list) {
    ssl->config->supported_group_list = (uint16_t *)BUF_memdup(
        ctx->supported_group_list, ctx->supported_group_list_len * 2);
    if (!ssl->config->supported_group_list) {
      goto err;
    }
    ssl->config->supported_group_list_len = ctx->supported_group_list_len;
  }

  if (ctx->alpn_client_proto_list) {
    ssl->config->alpn_client_proto_list = (uint8_t *)BUF_memdup(
        ctx->alpn_client_proto_list, ctx->alpn_client_proto_list_len);
    if (ssl->config->alpn_client_proto_list == NULL) {
      goto err;
    }
    ssl->config->alpn_client_proto_list_len = ctx->alpn_client_proto_list_len;
  }

  ssl->method = ctx->method;

  if (!ssl->method->ssl_new(ssl)) {
    goto err;
  }

  if (!ssl->ctx->x509_method->ssl_new(ssl->s3->hs.get())) {
    goto err;
  }

  CRYPTO_new_ex_data(&ssl->ex_data);

  if (ctx->psk_identity_hint) {
    ssl->config->psk_identity_hint = BUF_strdup(ctx->psk_identity_hint);
    if (ssl->config->psk_identity_hint == NULL) {
      goto err;
    }
  }
  ssl->config->psk_client_callback = ctx->psk_client_callback;
  ssl->config->psk_server_callback = ctx->psk_server_callback;

  ssl->config->tlsext_channel_id_enabled = ctx->tlsext_channel_id_enabled;
  if (ctx->tlsext_channel_id_private) {
    EVP_PKEY_up_ref(ctx->tlsext_channel_id_private);
    ssl->config->tlsext_channel_id_private = ctx->tlsext_channel_id_private;
  }

  ssl->config->signed_cert_timestamps_enabled =
      ctx->signed_cert_timestamps_enabled;
  ssl->config->ocsp_stapling_enabled = ctx->ocsp_stapling_enabled;
  ssl->config->handoff = ctx->handoff;

  return ssl;

err:
  SSL_free(ssl);
  OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);

  return NULL;
}

SSL_CONFIG::SSL_CONFIG(SSL *ssl_arg)
    : ssl(ssl_arg),
      signed_cert_timestamps_enabled(false),
      ocsp_stapling_enabled(false),
      tlsext_channel_id_enabled(false),
      retain_only_sha256_of_client_certs(false),
      handoff(false),
      shed_handshake_config(false) {
  assert(ssl);
}

SSL_CONFIG::~SSL_CONFIG() {
  if (ssl->ctx != nullptr) {
    ssl->ctx->x509_method->ssl_config_free(this);
  }
  Delete(cipher_list);
  Delete(cert);
  OPENSSL_free(psk_identity_hint);
  OPENSSL_free(supported_group_list);
  EVP_PKEY_free(tlsext_channel_id_private);
  OPENSSL_free(alpn_client_proto_list);
  OPENSSL_free(token_binding_params);
  OPENSSL_free(quic_transport_params);
  sk_SRTP_PROTECTION_PROFILE_free(srtp_profiles);
  sk_CRYPTO_BUFFER_pop_free(client_CA, CRYPTO_BUFFER_free);
}

void SSL_free(SSL *ssl) {
  if (ssl == NULL) {
    return;
  }

  CRYPTO_free_ex_data(&g_ex_data_class_ssl, ssl, &ssl->ex_data);

  BIO_free_all(ssl->rbio);
  BIO_free_all(ssl->wbio);

  Delete(ssl->config);
  ssl->config = NULL;

  SSL_SESSION_free(ssl->session);

  OPENSSL_free(ssl->tlsext_hostname);

  if (ssl->method != NULL) {
    ssl->method->ssl_free(ssl);
  }
  SSL_CTX_free(ssl->ctx);
  SSL_CTX_free(ssl->session_ctx);

  OPENSSL_free(ssl);
}

void SSL_set_connect_state(SSL *ssl) {
  ssl->server = false;
  ssl->do_handshake = ssl_client_handshake;
}

void SSL_set_accept_state(SSL *ssl) {
  ssl->server = true;
  ssl->do_handshake = ssl_server_handshake;
}

void SSL_set0_rbio(SSL *ssl, BIO *rbio) {
  BIO_free_all(ssl->rbio);
  ssl->rbio = rbio;
}

void SSL_set0_wbio(SSL *ssl, BIO *wbio) {
  BIO_free_all(ssl->wbio);
  ssl->wbio = wbio;
}

void SSL_set_bio(SSL *ssl, BIO *rbio, BIO *wbio) {
  // For historical reasons, this function has many different cases in ownership
  // handling.

  // If nothing has changed, do nothing
  if (rbio == SSL_get_rbio(ssl) && wbio == SSL_get_wbio(ssl)) {
    return;
  }

  // If the two arguments are equal, one fewer reference is granted than
  // taken.
  if (rbio != NULL && rbio == wbio) {
    BIO_up_ref(rbio);
  }

  // If only the wbio is changed, adopt only one reference.
  if (rbio == SSL_get_rbio(ssl)) {
    SSL_set0_wbio(ssl, wbio);
    return;
  }

  // There is an asymmetry here for historical reasons. If only the rbio is
  // changed AND the rbio and wbio were originally different, then we only adopt
  // one reference.
  if (wbio == SSL_get_wbio(ssl) && SSL_get_rbio(ssl) != SSL_get_wbio(ssl)) {
    SSL_set0_rbio(ssl, rbio);
    return;
  }

  // Otherwise, adopt both references.
  SSL_set0_rbio(ssl, rbio);
  SSL_set0_wbio(ssl, wbio);
}

BIO *SSL_get_rbio(const SSL *ssl) { return ssl->rbio; }

BIO *SSL_get_wbio(const SSL *ssl) { return ssl->wbio; }

int SSL_do_handshake(SSL *ssl) {
  ssl_reset_error_state(ssl);

  if (ssl->do_handshake == NULL) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_CONNECTION_TYPE_NOT_SET);
    return -1;
  }

  if (!SSL_in_init(ssl)) {
    return 1;
  }

  // Run the handshake.
  SSL_HANDSHAKE *hs = ssl->s3->hs.get();

  bool early_return = false;
  int ret = ssl_run_handshake(hs, &early_return);
  ssl_do_info_callback(
      ssl, ssl->server ? SSL_CB_ACCEPT_EXIT : SSL_CB_CONNECT_EXIT, ret);
  if (ret <= 0) {
    return ret;
  }

  // Destroy the handshake object if the handshake has completely finished.
  if (!early_return) {
    ssl->s3->hs.reset();
    ssl_maybe_shed_handshake_config(ssl);
  }

  return 1;
}

int SSL_connect(SSL *ssl) {
  if (ssl->do_handshake == NULL) {
    // Not properly initialized yet
    SSL_set_connect_state(ssl);
  }

  return SSL_do_handshake(ssl);
}

int SSL_accept(SSL *ssl) {
  if (ssl->do_handshake == NULL) {
    // Not properly initialized yet
    SSL_set_accept_state(ssl);
  }

  return SSL_do_handshake(ssl);
}

static int ssl_do_post_handshake(SSL *ssl, const SSLMessage &msg) {
  if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
    return tls13_post_handshake(ssl, msg);
  }

  // Check for renegotiation on the server before parsing to use the correct
  // error. Renegotiation is triggered by a different message for servers.
  if (ssl->server) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_NO_RENEGOTIATION);
    ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_NO_RENEGOTIATION);
    return 0;
  }

  if (msg.type != SSL3_MT_HELLO_REQUEST || CBS_len(&msg.body) != 0) {
    ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
    OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_HELLO_REQUEST);
    return 0;
  }

  if (ssl->renegotiate_mode == ssl_renegotiate_ignore) {
    return 1;  // Ignore the HelloRequest.
  }

  if (!ssl_can_renegotiate(ssl) ||
      // Renegotiation is only supported at quiescent points in the application
      // protocol, namely in HTTPS, just before reading the HTTP response.
      // Require the record-layer be idle and avoid complexities of sending a
      // handshake record while an application_data record is being written.
      !ssl->s3->write_buffer.empty() ||
      ssl->s3->write_shutdown != ssl_shutdown_none) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_NO_RENEGOTIATION);
    ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_NO_RENEGOTIATION);
    return 0;
  }

  // Begin a new handshake.
  if (ssl->s3->hs != nullptr) {
    OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
    return 0;
  }
  ssl->s3->hs = ssl_handshake_new(ssl);
  if (ssl->s3->hs == nullptr) {
    return 0;
  }

  ssl->s3->total_renegotiations++;
  return 1;
}

static int ssl_read_impl(SSL *ssl) {
  ssl_reset_error_state(ssl);

  if (ssl->do_handshake == NULL) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_UNINITIALIZED);
    return -1;
  }

  // Replay post-handshake message errors.
  if (!check_read_error(ssl)) {
    return -1;
  }

  while (ssl->s3->pending_app_data.empty()) {
    // Complete the current handshake, if any. False Start will cause
    // |SSL_do_handshake| to return mid-handshake, so this may require multiple
    // iterations.
    while (!ssl_can_read(ssl)) {
      int ret = SSL_do_handshake(ssl);
      if (ret < 0) {
        return ret;
      }
      if (ret == 0) {
        OPENSSL_PUT_ERROR(SSL, SSL_R_SSL_HANDSHAKE_FAILURE);
        return -1;
      }
    }

    // Process any buffered post-handshake messages.
    SSLMessage msg;
    if (ssl->method->get_message(ssl, &msg)) {
      // If we received an interrupt in early read (EndOfEarlyData), loop again
      // for the handshake to process it.
      if (SSL_in_init(ssl)) {
        ssl->s3->hs->can_early_read = false;
        continue;
      }

      // Handle the post-handshake message and try again.
      if (!ssl_do_post_handshake(ssl, msg)) {
        ssl_set_read_error(ssl);
        return -1;
      }
      ssl->method->next_message(ssl);
      continue;  // Loop again. We may have begun a new handshake.
    }

    uint8_t alert = SSL_AD_DECODE_ERROR;
    size_t consumed = 0;
    auto ret = ssl_open_app_data(ssl, &ssl->s3->pending_app_data, &consumed,
                                 &alert, ssl->s3->read_buffer.span());
    bool retry;
    int bio_ret = ssl_handle_open_record(ssl, &retry, ret, consumed, alert);
    if (bio_ret <= 0) {
      return bio_ret;
    }
    if (!retry) {
      assert(!ssl->s3->pending_app_data.empty());
      ssl->s3->key_update_count = 0;
    }
  }

  return 1;
}

int SSL_read(SSL *ssl, void *buf, int num) {
  int ret = SSL_peek(ssl, buf, num);
  if (ret <= 0) {
    return ret;
  }
  // TODO(davidben): In DTLS, should the rest of the record be discarded?  DTLS
  // is not a stream. See https://crbug.com/boringssl/65.
  ssl->s3->pending_app_data =
      ssl->s3->pending_app_data.subspan(static_cast<size_t>(ret));
  if (ssl->s3->pending_app_data.empty()) {
    ssl->s3->read_buffer.DiscardConsumed();
  }
  return ret;
}

int SSL_peek(SSL *ssl, void *buf, int num) {
  int ret = ssl_read_impl(ssl);
  if (ret <= 0) {
    return ret;
  }
  if (num <= 0) {
    return num;
  }
  size_t todo =
      std::min(ssl->s3->pending_app_data.size(), static_cast<size_t>(num));
  OPENSSL_memcpy(buf, ssl->s3->pending_app_data.data(), todo);
  return static_cast<int>(todo);
}

int SSL_write(SSL *ssl, const void *buf, int num) {
  ssl_reset_error_state(ssl);

  if (ssl->do_handshake == NULL) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_UNINITIALIZED);
    return -1;
  }

  if (ssl->s3->write_shutdown != ssl_shutdown_none) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_PROTOCOL_IS_SHUTDOWN);
    return -1;
  }

  int ret = 0;
  bool needs_handshake = false;
  do {
    // If necessary, complete the handshake implicitly.
    if (!ssl_can_write(ssl)) {
      ret = SSL_do_handshake(ssl);
      if (ret < 0) {
        return ret;
      }
      if (ret == 0) {
        OPENSSL_PUT_ERROR(SSL, SSL_R_SSL_HANDSHAKE_FAILURE);
        return -1;
      }
    }

    ret = ssl->method->write_app_data(ssl, &needs_handshake,
                                      (const uint8_t *)buf, num);
  } while (needs_handshake);
  return ret;
}

int SSL_shutdown(SSL *ssl) {
  ssl_reset_error_state(ssl);

  if (ssl->do_handshake == NULL) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_UNINITIALIZED);
    return -1;
  }

  // If we are in the middle of a handshake, silently succeed. Consumers often
  // call this function before |SSL_free|, whether the handshake succeeded or
  // not. We assume the caller has already handled failed handshakes.
  if (SSL_in_init(ssl)) {
    return 1;
  }

  if (ssl->quiet_shutdown) {
    // Do nothing if configured not to send a close_notify.
    ssl->s3->write_shutdown = ssl_shutdown_close_notify;
    ssl->s3->read_shutdown = ssl_shutdown_close_notify;
    return 1;
  }

  // This function completes in two stages. It sends a close_notify and then it
  // waits for a close_notify to come in. Perform exactly one action and return
  // whether or not it succeeds.

  if (ssl->s3->write_shutdown != ssl_shutdown_close_notify) {
    // Send a close_notify.
    if (ssl_send_alert(ssl, SSL3_AL_WARNING, SSL_AD_CLOSE_NOTIFY) <= 0) {
      return -1;
    }
  } else if (ssl->s3->alert_dispatch) {
    // Finish sending the close_notify.
    if (ssl->method->dispatch_alert(ssl) <= 0) {
      return -1;
    }
  } else if (ssl->s3->read_shutdown != ssl_shutdown_close_notify) {
    if (SSL_is_dtls(ssl)) {
      // Bidirectional shutdown doesn't make sense for an unordered
      // transport. DTLS alerts also aren't delivered reliably, so we may even
      // time out because the peer never received our close_notify. Report to
      // the caller that the channel has fully shut down.
      if (ssl->s3->read_shutdown == ssl_shutdown_error) {
        ERR_restore_state(ssl->s3->read_error.get());
        return -1;
      }
      ssl->s3->read_shutdown = ssl_shutdown_close_notify;
    } else {
      // Keep discarding data until we see a close_notify.
      for (;;) {
        ssl->s3->pending_app_data = Span<uint8_t>();
        int ret = ssl_read_impl(ssl);
        if (ret <= 0) {
          break;
        }
      }
      if (ssl->s3->read_shutdown != ssl_shutdown_close_notify) {
        return -1;
      }
    }
  }

  // Return 0 for unidirectional shutdown and 1 for bidirectional shutdown.
  return ssl->s3->read_shutdown == ssl_shutdown_close_notify;
}

int SSL_send_fatal_alert(SSL *ssl, uint8_t alert) {
  if (ssl->s3->alert_dispatch) {
    if (ssl->s3->send_alert[0] != SSL3_AL_FATAL ||
        ssl->s3->send_alert[1] != alert) {
      // We are already attempting to write a different alert.
      OPENSSL_PUT_ERROR(SSL, SSL_R_PROTOCOL_IS_SHUTDOWN);
      return -1;
    }
    return ssl->method->dispatch_alert(ssl);
  }

  return ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
}

int SSL_set_quic_transport_params(SSL *ssl, const uint8_t *params,
                                  size_t params_len) {
  if (!ssl->config) {
    return 0;
  }
  ssl->config->quic_transport_params =
      (uint8_t *)BUF_memdup(params, params_len);
  if (!ssl->config->quic_transport_params) {
    return 0;
  }
  ssl->config->quic_transport_params_len = params_len;
  return 1;
}

void SSL_get_peer_quic_transport_params(const SSL *ssl,
                                        const uint8_t **out_params,
                                        size_t *out_params_len) {
  *out_params = ssl->s3->peer_quic_transport_params.data();
  *out_params_len = ssl->s3->peer_quic_transport_params.size();
}

void SSL_CTX_set_early_data_enabled(SSL_CTX *ctx, int enabled) {
  ctx->enable_early_data = !!enabled;
}

void SSL_CTX_set_tls13_variant(SSL_CTX *ctx, enum tls13_variant_t variant) {
  ctx->tls13_variant = variant;
}

void SSL_set_tls13_variant(SSL *ssl, enum tls13_variant_t variant) {
  ssl->tls13_variant = variant;
}

void SSL_set_early_data_enabled(SSL *ssl, int enabled) {
  ssl->enable_early_data = !!enabled;
}

int SSL_in_early_data(const SSL *ssl) {
  if (ssl->s3->hs == NULL) {
    return 0;
  }
  return ssl->s3->hs->in_early_data;
}

int SSL_early_data_accepted(const SSL *ssl) {
  return ssl->s3->early_data_accepted;
}

void SSL_reset_early_data_reject(SSL *ssl) {
  SSL_HANDSHAKE *hs = ssl->s3->hs.get();
  if (hs == NULL ||
      hs->wait != ssl_hs_early_data_rejected) {
    abort();
  }

  hs->wait = ssl_hs_ok;
  hs->in_early_data = false;
  hs->early_session.reset();

  // Discard any unfinished writes from the perspective of |SSL_write|'s
  // retry. The handshake will transparently flush out the pending record
  // (discarded by the server) to keep the framing correct.
  ssl->s3->wpend_pending = false;
}

static int bio_retry_reason_to_error(int reason) {
  switch (reason) {
    case BIO_RR_CONNECT:
      return SSL_ERROR_WANT_CONNECT;
    case BIO_RR_ACCEPT:
      return SSL_ERROR_WANT_ACCEPT;
    default:
      return SSL_ERROR_SYSCALL;
  }
}

int SSL_get_error(const SSL *ssl, int ret_code) {
  if (ret_code > 0) {
    return SSL_ERROR_NONE;
  }

  // Make things return SSL_ERROR_SYSCALL when doing SSL_do_handshake etc,
  // where we do encode the error
  uint32_t err = ERR_peek_error();
  if (err != 0) {
    if (ERR_GET_LIB(err) == ERR_LIB_SYS) {
      return SSL_ERROR_SYSCALL;
    }
    return SSL_ERROR_SSL;
  }

  if (ret_code == 0) {
    if (ssl->s3->read_shutdown == ssl_shutdown_close_notify) {
      return SSL_ERROR_ZERO_RETURN;
    }
    // An EOF was observed which violates the protocol, and the underlying
    // transport does not participate in the error queue. Bubble up to the
    // caller.
    return SSL_ERROR_SYSCALL;
  }

  switch (ssl->s3->rwstate) {
    case SSL_PENDING_SESSION:
      return SSL_ERROR_PENDING_SESSION;

    case SSL_CERTIFICATE_SELECTION_PENDING:
      return SSL_ERROR_PENDING_CERTIFICATE;

    case SSL_HANDOFF:
      return SSL_ERROR_HANDOFF;

    case SSL_HANDBACK:
      return SSL_ERROR_HANDBACK;

    case SSL_READING: {
      BIO *bio = SSL_get_rbio(ssl);
      if (BIO_should_read(bio)) {
        return SSL_ERROR_WANT_READ;
      }

      if (BIO_should_write(bio)) {
        // TODO(davidben): OpenSSL historically checked for writes on the read
        // BIO. Can this be removed?
        return SSL_ERROR_WANT_WRITE;
      }

      if (BIO_should_io_special(bio)) {
        return bio_retry_reason_to_error(BIO_get_retry_reason(bio));
      }

      break;
    }

    case SSL_WRITING: {
      BIO *bio = SSL_get_wbio(ssl);
      if (BIO_should_write(bio)) {
        return SSL_ERROR_WANT_WRITE;
      }

      if (BIO_should_read(bio)) {
        // TODO(davidben): OpenSSL historically checked for reads on the write
        // BIO. Can this be removed?
        return SSL_ERROR_WANT_READ;
      }

      if (BIO_should_io_special(bio)) {
        return bio_retry_reason_to_error(BIO_get_retry_reason(bio));
      }

      break;
    }

    case SSL_X509_LOOKUP:
      return SSL_ERROR_WANT_X509_LOOKUP;

    case SSL_CHANNEL_ID_LOOKUP:
      return SSL_ERROR_WANT_CHANNEL_ID_LOOKUP;

    case SSL_PRIVATE_KEY_OPERATION:
      return SSL_ERROR_WANT_PRIVATE_KEY_OPERATION;

    case SSL_PENDING_TICKET:
      return SSL_ERROR_PENDING_TICKET;

    case SSL_EARLY_DATA_REJECTED:
      return SSL_ERROR_EARLY_DATA_REJECTED;

    case SSL_CERTIFICATE_VERIFY:
      return SSL_ERROR_WANT_CERTIFICATE_VERIFY;
  }

  return SSL_ERROR_SYSCALL;
}

uint32_t SSL_CTX_set_options(SSL_CTX *ctx, uint32_t options) {
  ctx->options |= options;
  return ctx->options;
}

uint32_t SSL_CTX_clear_options(SSL_CTX *ctx, uint32_t options) {
  ctx->options &= ~options;
  return ctx->options;
}

uint32_t SSL_CTX_get_options(const SSL_CTX *ctx) { return ctx->options; }

uint32_t SSL_set_options(SSL *ssl, uint32_t options) {
  ssl->options |= options;
  return ssl->options;
}

uint32_t SSL_clear_options(SSL *ssl, uint32_t options) {
  ssl->options &= ~options;
  return ssl->options;
}

uint32_t SSL_get_options(const SSL *ssl) { return ssl->options; }

uint32_t SSL_CTX_set_mode(SSL_CTX *ctx, uint32_t mode) {
  ctx->mode |= mode;
  return ctx->mode;
}

uint32_t SSL_CTX_clear_mode(SSL_CTX *ctx, uint32_t mode) {
  ctx->mode &= ~mode;
  return ctx->mode;
}

uint32_t SSL_CTX_get_mode(const SSL_CTX *ctx) { return ctx->mode; }

uint32_t SSL_set_mode(SSL *ssl, uint32_t mode) {
  ssl->mode |= mode;
  return ssl->mode;
}

uint32_t SSL_clear_mode(SSL *ssl, uint32_t mode) {
  ssl->mode &= ~mode;
  return ssl->mode;
}

uint32_t SSL_get_mode(const SSL *ssl) { return ssl->mode; }

void SSL_CTX_set0_buffer_pool(SSL_CTX *ctx, CRYPTO_BUFFER_POOL *pool) {
  ctx->pool = pool;
}

int SSL_get_tls_unique(const SSL *ssl, uint8_t *out, size_t *out_len,
                       size_t max_out) {
  *out_len = 0;
  OPENSSL_memset(out, 0, max_out);

  // tls-unique is not defined for SSL 3.0 or TLS 1.3.
  if (!ssl->s3->initial_handshake_complete ||
      ssl_protocol_version(ssl) < TLS1_VERSION ||
      ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
    return 0;
  }

  // The tls-unique value is the first Finished message in the handshake, which
  // is the client's in a full handshake and the server's for a resumption. See
  // https://tools.ietf.org/html/rfc5929#section-3.1.
  const uint8_t *finished = ssl->s3->previous_client_finished;
  size_t finished_len = ssl->s3->previous_client_finished_len;
  if (ssl->session != NULL) {
    // tls-unique is broken for resumed sessions unless EMS is used.
    if (!ssl->session->extended_master_secret) {
      return 0;
    }
    finished = ssl->s3->previous_server_finished;
    finished_len = ssl->s3->previous_server_finished_len;
  }

  *out_len = finished_len;
  if (finished_len > max_out) {
    *out_len = max_out;
  }

  OPENSSL_memcpy(out, finished, *out_len);
  return 1;
}

static int set_session_id_context(CERT *cert, const uint8_t *sid_ctx,
                                   size_t sid_ctx_len) {
  if (sid_ctx_len > sizeof(cert->sid_ctx)) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_SSL_SESSION_ID_CONTEXT_TOO_LONG);
    return 0;
  }

  static_assert(sizeof(cert->sid_ctx) < 256, "sid_ctx too large");
  cert->sid_ctx_length = (uint8_t)sid_ctx_len;
  OPENSSL_memcpy(cert->sid_ctx, sid_ctx, sid_ctx_len);
  return 1;
}

int SSL_CTX_set_session_id_context(SSL_CTX *ctx, const uint8_t *sid_ctx,
                                   size_t sid_ctx_len) {
  return set_session_id_context(ctx->cert, sid_ctx, sid_ctx_len);
}

int SSL_set_session_id_context(SSL *ssl, const uint8_t *sid_ctx,
                               size_t sid_ctx_len) {
  if (!ssl->config) {
    return 0;
  }
  return set_session_id_context(ssl->config->cert, sid_ctx, sid_ctx_len);
}

const uint8_t *SSL_get0_session_id_context(const SSL *ssl, size_t *out_len) {
  if (!ssl->config) {
    assert(ssl->config);
    *out_len = 0;
    return NULL;
  }
  *out_len = ssl->config->cert->sid_ctx_length;
  return ssl->config->cert->sid_ctx;
}

void SSL_certs_clear(SSL *ssl) {
  if (!ssl->config) {
    return;
  }
  ssl_cert_clear_certs(ssl->config->cert);
}

int SSL_get_fd(const SSL *ssl) { return SSL_get_rfd(ssl); }

int SSL_get_rfd(const SSL *ssl) {
  int ret = -1;
  BIO *b = BIO_find_type(SSL_get_rbio(ssl), BIO_TYPE_DESCRIPTOR);
  if (b != NULL) {
    BIO_get_fd(b, &ret);
  }
  return ret;
}

int SSL_get_wfd(const SSL *ssl) {
  int ret = -1;
  BIO *b = BIO_find_type(SSL_get_wbio(ssl), BIO_TYPE_DESCRIPTOR);
  if (b != NULL) {
    BIO_get_fd(b, &ret);
  }
  return ret;
}

int SSL_set_fd(SSL *ssl, int fd) {
  BIO *bio = BIO_new(BIO_s_socket());
  if (bio == NULL) {
    OPENSSL_PUT_ERROR(SSL, ERR_R_BUF_LIB);
    return 0;
  }
  BIO_set_fd(bio, fd, BIO_NOCLOSE);
  SSL_set_bio(ssl, bio, bio);
  return 1;
}

int SSL_set_wfd(SSL *ssl, int fd) {
  BIO *rbio = SSL_get_rbio(ssl);
  if (rbio == NULL || BIO_method_type(rbio) != BIO_TYPE_SOCKET ||
      BIO_get_fd(rbio, NULL) != fd) {
    BIO *bio = BIO_new(BIO_s_socket());
    if (bio == NULL) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_BUF_LIB);
      return 0;
    }
    BIO_set_fd(bio, fd, BIO_NOCLOSE);
    SSL_set0_wbio(ssl, bio);
  } else {
    // Copy the rbio over to the wbio.
    BIO_up_ref(rbio);
    SSL_set0_wbio(ssl, rbio);
  }

  return 1;
}

int SSL_set_rfd(SSL *ssl, int fd) {
  BIO *wbio = SSL_get_wbio(ssl);
  if (wbio == NULL || BIO_method_type(wbio) != BIO_TYPE_SOCKET ||
      BIO_get_fd(wbio, NULL) != fd) {
    BIO *bio = BIO_new(BIO_s_socket());
    if (bio == NULL) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_BUF_LIB);
      return 0;
    }
    BIO_set_fd(bio, fd, BIO_NOCLOSE);
    SSL_set0_rbio(ssl, bio);
  } else {
    // Copy the wbio over to the rbio.
    BIO_up_ref(wbio);
    SSL_set0_rbio(ssl, wbio);
  }
  return 1;
}

static size_t copy_finished(void *out, size_t out_len, const uint8_t *in,
                            size_t in_len) {
  if (out_len > in_len) {
    out_len = in_len;
  }
  OPENSSL_memcpy(out, in, out_len);
  return in_len;
}

size_t SSL_get_finished(const SSL *ssl, void *buf, size_t count) {
  if (!ssl->s3->initial_handshake_complete ||
      ssl_protocol_version(ssl) < TLS1_VERSION ||
      ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
    return 0;
  }

  if (ssl->server) {
    return copy_finished(buf, count, ssl->s3->previous_server_finished,
                         ssl->s3->previous_server_finished_len);
  }

  return copy_finished(buf, count, ssl->s3->previous_client_finished,
                       ssl->s3->previous_client_finished_len);
}

size_t SSL_get_peer_finished(const SSL *ssl, void *buf, size_t count) {
  if (!ssl->s3->initial_handshake_complete ||
      ssl_protocol_version(ssl) < TLS1_VERSION ||
      ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
    return 0;
  }

  if (ssl->server) {
    return copy_finished(buf, count, ssl->s3->previous_client_finished,
                         ssl->s3->previous_client_finished_len);
  }

  return copy_finished(buf, count, ssl->s3->previous_server_finished,
                       ssl->s3->previous_server_finished_len);
}

int SSL_get_verify_mode(const SSL *ssl) {
  if (!ssl->config) {
    assert(ssl->config);
    return -1;
  }
  return ssl->config->verify_mode;
}

int SSL_get_extms_support(const SSL *ssl) {
  // TLS 1.3 does not require extended master secret and always reports as
  // supporting it.
  if (!ssl->s3->have_version) {
    return 0;
  }
  if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
    return 1;
  }

  // If the initial handshake completed, query the established session.
  if (ssl->s3->established_session != NULL) {
    return ssl->s3->established_session->extended_master_secret;
  }

  // Otherwise, query the in-progress handshake.
  if (ssl->s3->hs != NULL) {
    return ssl->s3->hs->extended_master_secret;
  }
  assert(0);
  return 0;
}

int SSL_CTX_get_read_ahead(const SSL_CTX *ctx) { return 0; }

int SSL_get_read_ahead(const SSL *ssl) { return 0; }

void SSL_CTX_set_read_ahead(SSL_CTX *ctx, int yes) { }

void SSL_set_read_ahead(SSL *ssl, int yes) { }

int SSL_pending(const SSL *ssl) {
  return static_cast<int>(ssl->s3->pending_app_data.size());
}

// Fix this so it checks all the valid key/cert options
int SSL_CTX_check_private_key(const SSL_CTX *ctx) {
  return ssl_cert_check_private_key(ctx->cert, ctx->cert->privatekey.get());
}

// Fix this function so that it takes an optional type parameter
int SSL_check_private_key(const SSL *ssl) {
  if (!ssl->config) {
    return 0;
  }
  return ssl_cert_check_private_key(ssl->config->cert,
                                    ssl->config->cert->privatekey.get());
}

long SSL_get_default_timeout(const SSL *ssl) {
  return SSL_DEFAULT_SESSION_TIMEOUT;
}

int SSL_renegotiate(SSL *ssl) {
  // Caller-initiated renegotiation is not supported.
  OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
  return 0;
}

int SSL_renegotiate_pending(SSL *ssl) {
  return SSL_in_init(ssl) && ssl->s3->initial_handshake_complete;
}

int SSL_total_renegotiations(const SSL *ssl) {
  return ssl->s3->total_renegotiations;
}

size_t SSL_CTX_get_max_cert_list(const SSL_CTX *ctx) {
  return ctx->max_cert_list;
}

void SSL_CTX_set_max_cert_list(SSL_CTX *ctx, size_t max_cert_list) {
  if (max_cert_list > kMaxHandshakeSize) {
    max_cert_list = kMaxHandshakeSize;
  }
  ctx->max_cert_list = (uint32_t)max_cert_list;
}

size_t SSL_get_max_cert_list(const SSL *ssl) {
  return ssl->max_cert_list;
}

void SSL_set_max_cert_list(SSL *ssl, size_t max_cert_list) {
  if (max_cert_list > kMaxHandshakeSize) {
    max_cert_list = kMaxHandshakeSize;
  }
  ssl->max_cert_list = (uint32_t)max_cert_list;
}

int SSL_CTX_set_max_send_fragment(SSL_CTX *ctx, size_t max_send_fragment) {
  if (max_send_fragment < 512) {
    max_send_fragment = 512;
  }
  if (max_send_fragment > SSL3_RT_MAX_PLAIN_LENGTH) {
    max_send_fragment = SSL3_RT_MAX_PLAIN_LENGTH;
  }
  ctx->max_send_fragment = (uint16_t)max_send_fragment;

  return 1;
}

int SSL_set_max_send_fragment(SSL *ssl, size_t max_send_fragment) {
  if (max_send_fragment < 512) {
    max_send_fragment = 512;
  }
  if (max_send_fragment > SSL3_RT_MAX_PLAIN_LENGTH) {
    max_send_fragment = SSL3_RT_MAX_PLAIN_LENGTH;
  }
  ssl->max_send_fragment = (uint16_t)max_send_fragment;

  return 1;
}

int SSL_set_mtu(SSL *ssl, unsigned mtu) {
  if (!SSL_is_dtls(ssl) || mtu < dtls1_min_mtu()) {
    return 0;
  }
  ssl->d1->mtu = mtu;
  return 1;
}

int SSL_get_secure_renegotiation_support(const SSL *ssl) {
  if (!ssl->s3->have_version) {
    return 0;
  }
  return ssl_protocol_version(ssl) >= TLS1_3_VERSION ||
         ssl->s3->send_connection_binding;
}

size_t SSL_CTX_sess_number(const SSL_CTX *ctx) {
  MutexReadLock lock(const_cast<CRYPTO_MUTEX *>(&ctx->lock));
  return lh_SSL_SESSION_num_items(ctx->sessions);
}

unsigned long SSL_CTX_sess_set_cache_size(SSL_CTX *ctx, unsigned long size) {
  unsigned long ret = ctx->session_cache_size;
  ctx->session_cache_size = size;
  return ret;
}

unsigned long SSL_CTX_sess_get_cache_size(const SSL_CTX *ctx) {
  return ctx->session_cache_size;
}

int SSL_CTX_set_session_cache_mode(SSL_CTX *ctx, int mode) {
  int ret = ctx->session_cache_mode;
  ctx->session_cache_mode = mode;
  return ret;
}

int SSL_CTX_get_session_cache_mode(const SSL_CTX *ctx) {
  return ctx->session_cache_mode;
}


int SSL_CTX_get_tlsext_ticket_keys(SSL_CTX *ctx, void *out, size_t len) {
  if (out == NULL) {
    return 48;
  }
  if (len != 48) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_TICKET_KEYS_LENGTH);
    return 0;
  }

  // The default ticket keys are initialized lazily. Trigger a key
  // rotation to initialize them.
  if (!ssl_ctx_rotate_ticket_encryption_key(ctx)) {
    return 0;
  }

  uint8_t *out_bytes = reinterpret_cast<uint8_t *>(out);
  MutexReadLock lock(&ctx->lock);
  OPENSSL_memcpy(out_bytes, ctx->tlsext_ticket_key_current->name, 16);
  OPENSSL_memcpy(out_bytes + 16, ctx->tlsext_ticket_key_current->hmac_key, 16);
  OPENSSL_memcpy(out_bytes + 32, ctx->tlsext_ticket_key_current->aes_key, 16);
  return 1;
}

int SSL_CTX_set_tlsext_ticket_keys(SSL_CTX *ctx, const void *in, size_t len) {
  if (in == NULL) {
    return 48;
  }
  if (len != 48) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_TICKET_KEYS_LENGTH);
    return 0;
  }
  if (!ctx->tlsext_ticket_key_current) {
    ctx->tlsext_ticket_key_current =
        (tlsext_ticket_key *)OPENSSL_malloc(sizeof(tlsext_ticket_key));
    if (!ctx->tlsext_ticket_key_current) {
      return 0;
    }
  }
  OPENSSL_memset(ctx->tlsext_ticket_key_current, 0, sizeof(tlsext_ticket_key));
  const uint8_t *in_bytes = reinterpret_cast<const uint8_t *>(in);
  OPENSSL_memcpy(ctx->tlsext_ticket_key_current->name, in_bytes, 16);
  OPENSSL_memcpy(ctx->tlsext_ticket_key_current->hmac_key, in_bytes + 16, 16);
  OPENSSL_memcpy(ctx->tlsext_ticket_key_current->aes_key, in_bytes + 32, 16);
  OPENSSL_free(ctx->tlsext_ticket_key_prev);
  ctx->tlsext_ticket_key_prev = nullptr;
  // Disable automatic key rotation.
  ctx->tlsext_ticket_key_current->next_rotation_tv_sec = 0;
  return 1;
}

int SSL_CTX_set_tlsext_ticket_key_cb(
    SSL_CTX *ctx, int (*callback)(SSL *ssl, uint8_t *key_name, uint8_t *iv,
                                  EVP_CIPHER_CTX *ctx, HMAC_CTX *hmac_ctx,
                                  int encrypt)) {
  ctx->tlsext_ticket_key_cb = callback;
  return 1;
}

int SSL_CTX_set1_curves(SSL_CTX *ctx, const int *curves, size_t curves_len) {
  return tls1_set_curves(&ctx->supported_group_list,
                         &ctx->supported_group_list_len, curves,
                         curves_len);
}

int SSL_set1_curves(SSL *ssl, const int *curves, size_t curves_len) {
  if (!ssl->config) {
    return 0;
  }
  return tls1_set_curves(&ssl->config->supported_group_list,
                         &ssl->config->supported_group_list_len, curves,
                         curves_len);
}

int SSL_CTX_set1_curves_list(SSL_CTX *ctx, const char *curves) {
  return tls1_set_curves_list(&ctx->supported_group_list,
                              &ctx->supported_group_list_len, curves);
}

int SSL_set1_curves_list(SSL *ssl, const char *curves) {
  if (!ssl->config) {
    return 0;
  }
  return tls1_set_curves_list(&ssl->config->supported_group_list,
                              &ssl->config->supported_group_list_len, curves);
}

uint16_t SSL_get_curve_id(const SSL *ssl) {
  // TODO(davidben): This checks the wrong session if there is a renegotiation
  // in progress.
  SSL_SESSION *session = SSL_get_session(ssl);
  if (session == NULL) {
    return 0;
  }

  return session->group_id;
}

int SSL_CTX_set_tmp_dh(SSL_CTX *ctx, const DH *dh) {
  return 1;
}

int SSL_set_tmp_dh(SSL *ssl, const DH *dh) {
  return 1;
}

STACK_OF(SSL_CIPHER) *SSL_CTX_get_ciphers(const SSL_CTX *ctx) {
  return ctx->cipher_list->ciphers.get();
}

int SSL_CTX_cipher_in_group(const SSL_CTX *ctx, size_t i) {
  if (i >= sk_SSL_CIPHER_num(ctx->cipher_list->ciphers.get())) {
    return 0;
  }
  return ctx->cipher_list->in_group_flags[i];
}

STACK_OF(SSL_CIPHER) *SSL_get_ciphers(const SSL *ssl) {
  if (ssl == NULL) {
    return NULL;
  }
  if (ssl->config == NULL) {
    assert(ssl->config);
    return NULL;
  }

  return ssl->config->cipher_list ? ssl->config->cipher_list->ciphers.get()
      : ssl->ctx->cipher_list->ciphers.get();
}

const char *SSL_get_cipher_list(const SSL *ssl, int n) {
  if (ssl == NULL) {
    return NULL;
  }

  STACK_OF(SSL_CIPHER) *sk = SSL_get_ciphers(ssl);
  if (sk == NULL || n < 0 || (size_t)n >= sk_SSL_CIPHER_num(sk)) {
    return NULL;
  }

  const SSL_CIPHER *c = sk_SSL_CIPHER_value(sk, n);
  if (c == NULL) {
    return NULL;
  }

  return c->name;
}

int SSL_CTX_set_cipher_list(SSL_CTX *ctx, const char *str) {
  return ssl_create_cipher_list(&ctx->cipher_list, str, false /* not strict */);
}

int SSL_CTX_set_strict_cipher_list(SSL_CTX *ctx, const char *str) {
  return ssl_create_cipher_list(&ctx->cipher_list, str, true /* strict */);
}

int SSL_set_cipher_list(SSL *ssl, const char *str) {
  if (!ssl->config) {
    return 0;
  }
  return ssl_create_cipher_list(&ssl->config->cipher_list, str,
                                false /* not strict */);
}

int SSL_set_strict_cipher_list(SSL *ssl, const char *str) {
  if (!ssl->config) {
    return 0;
  }
  return ssl_create_cipher_list(&ssl->config->cipher_list, str,
                                true /* strict */);
}

const char *SSL_get_servername(const SSL *ssl, const int type) {
  if (type != TLSEXT_NAMETYPE_host_name) {
    return NULL;
  }

  // Historically, |SSL_get_servername| was also the configuration getter
  // corresponding to |SSL_set_tlsext_host_name|.
  if (ssl->tlsext_hostname != NULL) {
    return ssl->tlsext_hostname;
  }

  return ssl->s3->hostname.get();
}

int SSL_get_servername_type(const SSL *ssl) {
  if (SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name) == NULL) {
    return -1;
  }
  return TLSEXT_NAMETYPE_host_name;
}

void SSL_CTX_set_custom_verify(
    SSL_CTX *ctx, int mode,
    enum ssl_verify_result_t (*callback)(SSL *ssl, uint8_t *out_alert)) {
  ctx->verify_mode = mode;
  ctx->custom_verify_callback = callback;
}

void SSL_set_custom_verify(
    SSL *ssl, int mode,
    enum ssl_verify_result_t (*callback)(SSL *ssl, uint8_t *out_alert)) {
  if (!ssl->config) {
    return;
  }
  ssl->config->verify_mode = mode;
  ssl->config->custom_verify_callback = callback;
}

void SSL_CTX_enable_signed_cert_timestamps(SSL_CTX *ctx) {
  ctx->signed_cert_timestamps_enabled = true;
}

void SSL_enable_signed_cert_timestamps(SSL *ssl) {
  if (!ssl->config) {
    return;
  }
  ssl->config->signed_cert_timestamps_enabled = true;
}

void SSL_CTX_enable_ocsp_stapling(SSL_CTX *ctx) {
  ctx->ocsp_stapling_enabled = true;
}

void SSL_enable_ocsp_stapling(SSL *ssl) {
  if (!ssl->config) {
    return;
  }
  ssl->config->ocsp_stapling_enabled = true;
}

void SSL_get0_signed_cert_timestamp_list(const SSL *ssl, const uint8_t **out,
                                         size_t *out_len) {
  SSL_SESSION *session = SSL_get_session(ssl);
  if (ssl->server || !session || !session->signed_cert_timestamp_list) {
    *out_len = 0;
    *out = NULL;
    return;
  }

  *out = CRYPTO_BUFFER_data(session->signed_cert_timestamp_list);
  *out_len = CRYPTO_BUFFER_len(session->signed_cert_timestamp_list);
}

void SSL_get0_ocsp_response(const SSL *ssl, const uint8_t **out,
                            size_t *out_len) {
  SSL_SESSION *session = SSL_get_session(ssl);
  if (ssl->server || !session || !session->ocsp_response) {
    *out_len = 0;
    *out = NULL;
    return;
  }

  *out = CRYPTO_BUFFER_data(session->ocsp_response);
  *out_len = CRYPTO_BUFFER_len(session->ocsp_response);
}

int SSL_set_tlsext_host_name(SSL *ssl, const char *name) {
  OPENSSL_free(ssl->tlsext_hostname);
  ssl->tlsext_hostname = NULL;

  if (name == NULL) {
    return 1;
  }

  size_t len = strlen(name);
  if (len == 0 || len > TLSEXT_MAXLEN_host_name) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_SSL3_EXT_INVALID_SERVERNAME);
    return 0;
  }
  ssl->tlsext_hostname = BUF_strdup(name);
  if (ssl->tlsext_hostname == NULL) {
    OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
    return 0;
  }
  return 1;
}

int SSL_CTX_set_tlsext_servername_callback(
    SSL_CTX *ctx, int (*callback)(SSL *ssl, int *out_alert, void *arg)) {
  ctx->tlsext_servername_callback = callback;
  return 1;
}

int SSL_CTX_set_tlsext_servername_arg(SSL_CTX *ctx, void *arg) {
  ctx->tlsext_servername_arg = arg;
  return 1;
}

int SSL_select_next_proto(uint8_t **out, uint8_t *out_len, const uint8_t *peer,
                          unsigned peer_len, const uint8_t *supported,
                          unsigned supported_len) {
  const uint8_t *result;
  int status;

  // For each protocol in peer preference order, see if we support it.
  for (unsigned i = 0; i < peer_len;) {
    for (unsigned j = 0; j < supported_len;) {
      if (peer[i] == supported[j] &&
          OPENSSL_memcmp(&peer[i + 1], &supported[j + 1], peer[i]) == 0) {
        // We found a match
        result = &peer[i];
        status = OPENSSL_NPN_NEGOTIATED;
        goto found;
      }
      j += supported[j];
      j++;
    }
    i += peer[i];
    i++;
  }

  // There's no overlap between our protocols and the peer's list.
  result = supported;
  status = OPENSSL_NPN_NO_OVERLAP;

found:
  *out = (uint8_t *)result + 1;
  *out_len = result[0];
  return status;
}

void SSL_get0_next_proto_negotiated(const SSL *ssl, const uint8_t **out_data,
                                    unsigned *out_len) {
  *out_data = ssl->s3->next_proto_negotiated.data();
  *out_len = ssl->s3->next_proto_negotiated.size();
}

void SSL_CTX_set_next_protos_advertised_cb(
    SSL_CTX *ctx,
    int (*cb)(SSL *ssl, const uint8_t **out, unsigned *out_len, void *arg),
    void *arg) {
  ctx->next_protos_advertised_cb = cb;
  ctx->next_protos_advertised_cb_arg = arg;
}

void SSL_CTX_set_next_proto_select_cb(
    SSL_CTX *ctx, int (*cb)(SSL *ssl, uint8_t **out, uint8_t *out_len,
                            const uint8_t *in, unsigned in_len, void *arg),
    void *arg) {
  ctx->next_proto_select_cb = cb;
  ctx->next_proto_select_cb_arg = arg;
}

int SSL_CTX_set_alpn_protos(SSL_CTX *ctx, const uint8_t *protos,
                            unsigned protos_len) {
  OPENSSL_free(ctx->alpn_client_proto_list);
  ctx->alpn_client_proto_list = (uint8_t *)BUF_memdup(protos, protos_len);
  if (!ctx->alpn_client_proto_list) {
    return 1;
  }
  ctx->alpn_client_proto_list_len = protos_len;

  return 0;
}

int SSL_set_alpn_protos(SSL *ssl, const uint8_t *protos, unsigned protos_len) {
  if (!ssl->config) {
    return 0;
  }
  OPENSSL_free(ssl->config->alpn_client_proto_list);
  ssl->config->alpn_client_proto_list =
      (uint8_t *)BUF_memdup(protos, protos_len);
  if (!ssl->config->alpn_client_proto_list) {
    return 1;
  }
  ssl->config->alpn_client_proto_list_len = protos_len;

  return 0;
}

void SSL_CTX_set_alpn_select_cb(SSL_CTX *ctx,
                                int (*cb)(SSL *ssl, const uint8_t **out,
                                          uint8_t *out_len, const uint8_t *in,
                                          unsigned in_len, void *arg),
                                void *arg) {
  ctx->alpn_select_cb = cb;
  ctx->alpn_select_cb_arg = arg;
}

void SSL_get0_alpn_selected(const SSL *ssl, const uint8_t **out_data,
                            unsigned *out_len) {
  if (SSL_in_early_data(ssl) && !ssl->server) {
    *out_data = ssl->s3->hs->early_session->early_alpn;
    *out_len = ssl->s3->hs->early_session->early_alpn_len;
  } else {
    *out_data = ssl->s3->alpn_selected.data();
    *out_len = ssl->s3->alpn_selected.size();
  }
}

void SSL_CTX_set_allow_unknown_alpn_protos(SSL_CTX *ctx, int enabled) {
  ctx->allow_unknown_alpn_protos = !!enabled;
}

void SSL_CTX_set_tls_channel_id_enabled(SSL_CTX *ctx, int enabled) {
  ctx->tlsext_channel_id_enabled = !!enabled;
}

int SSL_CTX_enable_tls_channel_id(SSL_CTX *ctx) {
  SSL_CTX_set_tls_channel_id_enabled(ctx, 1);
  return 1;
}

void SSL_set_tls_channel_id_enabled(SSL *ssl, int enabled) {
  if (!ssl->config) {
    return;
  }
  ssl->config->tlsext_channel_id_enabled = !!enabled;
}

int SSL_enable_tls_channel_id(SSL *ssl) {
  SSL_set_tls_channel_id_enabled(ssl, 1);
  return 1;
}

static int is_p256_key(EVP_PKEY *private_key) {
  const EC_KEY *ec_key = EVP_PKEY_get0_EC_KEY(private_key);
  return ec_key != NULL &&
         EC_GROUP_get_curve_name(EC_KEY_get0_group(ec_key)) ==
             NID_X9_62_prime256v1;
}

int SSL_CTX_set1_tls_channel_id(SSL_CTX *ctx, EVP_PKEY *private_key) {
  if (!is_p256_key(private_key)) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_CHANNEL_ID_NOT_P256);
    return 0;
  }

  EVP_PKEY_free(ctx->tlsext_channel_id_private);
  EVP_PKEY_up_ref(private_key);
  ctx->tlsext_channel_id_private = private_key;
  ctx->tlsext_channel_id_enabled = true;

  return 1;
}

int SSL_set1_tls_channel_id(SSL *ssl, EVP_PKEY *private_key) {
  if (!ssl->config) {
    return 0;
  }
  if (!is_p256_key(private_key)) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_CHANNEL_ID_NOT_P256);
    return 0;
  }

  EVP_PKEY_free(ssl->config->tlsext_channel_id_private);
  EVP_PKEY_up_ref(private_key);
  ssl->config->tlsext_channel_id_private = private_key;
  ssl->config->tlsext_channel_id_enabled = true;

  return 1;
}

size_t SSL_get_tls_channel_id(SSL *ssl, uint8_t *out, size_t max_out) {
  if (!ssl->s3->tlsext_channel_id_valid) {
    return 0;
  }
  OPENSSL_memcpy(out, ssl->s3->tlsext_channel_id,
                 (max_out < 64) ? max_out : 64);
  return 64;
}

int SSL_set_token_binding_params(SSL *ssl, const uint8_t *params, size_t len) {
  if (!ssl->config) {
    return 0;
  }
  if (len > 256) {
    OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW);
    return 0;
  }
  OPENSSL_free(ssl->config->token_binding_params);
  ssl->config->token_binding_params = (uint8_t *)BUF_memdup(params, len);
  if (!ssl->config->token_binding_params) {
    return 0;
  }
  ssl->config->token_binding_params_len = len;
  return 1;
}

int SSL_is_token_binding_negotiated(const SSL *ssl) {
  return ssl->s3->token_binding_negotiated;
}

uint8_t SSL_get_negotiated_token_binding_param(const SSL *ssl) {
  return ssl->s3->negotiated_token_binding_param;
}

size_t SSL_get0_certificate_types(SSL *ssl, const uint8_t **out_types) {
  if (ssl->server || ssl->s3->hs == NULL) {
    *out_types = NULL;
    return 0;
  }
  *out_types = ssl->s3->hs->certificate_types.data();
  return ssl->s3->hs->certificate_types.size();
}

EVP_PKEY *SSL_get_privatekey(const SSL *ssl) {
  if (!ssl->config) {
    assert(ssl->config);
    return NULL;
  }
  if (ssl->config->cert != NULL) {
    return ssl->config->cert->privatekey.get();
  }

  return NULL;
}

EVP_PKEY *SSL_CTX_get0_privatekey(const SSL_CTX *ctx) {
  if (ctx->cert != NULL) {
    return ctx->cert->privatekey.get();
  }

  return NULL;
}

const SSL_CIPHER *SSL_get_current_cipher(const SSL *ssl) {
  return ssl->s3->aead_write_ctx->cipher();
}

int SSL_session_reused(const SSL *ssl) {
  return ssl->s3->session_reused || SSL_in_early_data(ssl);
}

const COMP_METHOD *SSL_get_current_compression(SSL *ssl) { return NULL; }

const COMP_METHOD *SSL_get_current_expansion(SSL *ssl) { return NULL; }

int *SSL_get_server_tmp_key(SSL *ssl, EVP_PKEY **out_key) { return 0; }

void SSL_CTX_set_quiet_shutdown(SSL_CTX *ctx, int mode) {
  ctx->quiet_shutdown = (mode != 0);
}

int SSL_CTX_get_quiet_shutdown(const SSL_CTX *ctx) {
  return ctx->quiet_shutdown;
}

void SSL_set_quiet_shutdown(SSL *ssl, int mode) {
  ssl->quiet_shutdown = (mode != 0);
}

int SSL_get_quiet_shutdown(const SSL *ssl) { return ssl->quiet_shutdown; }

void SSL_set_shutdown(SSL *ssl, int mode) {
  // It is an error to clear any bits that have already been set. (We can't try
  // to get a second close_notify or send two.)
  assert((SSL_get_shutdown(ssl) & mode) == SSL_get_shutdown(ssl));

  if (mode & SSL_RECEIVED_SHUTDOWN &&
      ssl->s3->read_shutdown == ssl_shutdown_none) {
    ssl->s3->read_shutdown = ssl_shutdown_close_notify;
  }

  if (mode & SSL_SENT_SHUTDOWN &&
      ssl->s3->write_shutdown == ssl_shutdown_none) {
    ssl->s3->write_shutdown = ssl_shutdown_close_notify;
  }
}

int SSL_get_shutdown(const SSL *ssl) {
  int ret = 0;
  if (ssl->s3->read_shutdown != ssl_shutdown_none) {
    // Historically, OpenSSL set |SSL_RECEIVED_SHUTDOWN| on both close_notify
    // and fatal alert.
    ret |= SSL_RECEIVED_SHUTDOWN;
  }
  if (ssl->s3->write_shutdown == ssl_shutdown_close_notify) {
    // Historically, OpenSSL set |SSL_SENT_SHUTDOWN| on only close_notify.
    ret |= SSL_SENT_SHUTDOWN;
  }
  return ret;
}

SSL_CTX *SSL_get_SSL_CTX(const SSL *ssl) { return ssl->ctx; }

SSL_CTX *SSL_set_SSL_CTX(SSL *ssl, SSL_CTX *ctx) {
  if (!ssl->config) {
    return NULL;
  }
  if (ssl->ctx == ctx) {
    return ssl->ctx;
  }

  // One cannot change the X.509 callbacks during a connection.
  if (ssl->ctx->x509_method != ctx->x509_method) {
    assert(0);
    return NULL;
  }

  if (ctx == NULL) {
    ctx = ssl->session_ctx;
  }

  Delete(ssl->config->cert);
  ssl->config->cert = ssl_cert_dup(ctx->cert).release();

  SSL_CTX_up_ref(ctx);
  SSL_CTX_free(ssl->ctx);
  ssl->ctx = ctx;
  ssl->enable_early_data = ssl->ctx->enable_early_data;

  return ssl->ctx;
}

void SSL_set_info_callback(SSL *ssl,
                           void (*cb)(const SSL *ssl, int type, int value)) {
  ssl->info_callback = cb;
}

void (*SSL_get_info_callback(const SSL *ssl))(const SSL *ssl, int type,
                                              int value) {
  return ssl->info_callback;
}

int SSL_state(const SSL *ssl) {
  return SSL_in_init(ssl) ? SSL_ST_INIT : SSL_ST_OK;
}

void SSL_set_state(SSL *ssl, int state) { }

char *SSL_get_shared_ciphers(const SSL *ssl, char *buf, int len) {
  if (len <= 0) {
    return NULL;
  }
  buf[0] = '\0';
  return buf;
}

int SSL_get_ex_new_index(long argl, void *argp, CRYPTO_EX_unused *unused,
                         CRYPTO_EX_dup *dup_unused, CRYPTO_EX_free *free_func) {
  int index;
  if (!CRYPTO_get_ex_new_index(&g_ex_data_class_ssl, &index, argl, argp,
                               free_func)) {
    return -1;
  }
  return index;
}

int SSL_set_ex_data(SSL *ssl, int idx, void *data) {
  return CRYPTO_set_ex_data(&ssl->ex_data, idx, data);
}

void *SSL_get_ex_data(const SSL *ssl, int idx) {
  return CRYPTO_get_ex_data(&ssl->ex_data, idx);
}

int SSL_CTX_get_ex_new_index(long argl, void *argp, CRYPTO_EX_unused *unused,
                             CRYPTO_EX_dup *dup_unused,
                             CRYPTO_EX_free *free_func) {
  int index;
  if (!CRYPTO_get_ex_new_index(&g_ex_data_class_ssl_ctx, &index, argl, argp,
                               free_func)) {
    return -1;
  }
  return index;
}

int SSL_CTX_set_ex_data(SSL_CTX *ctx, int idx, void *data) {
  return CRYPTO_set_ex_data(&ctx->ex_data, idx, data);
}

void *SSL_CTX_get_ex_data(const SSL_CTX *ctx, int idx) {
  return CRYPTO_get_ex_data(&ctx->ex_data, idx);
}

int SSL_want(const SSL *ssl) { return ssl->s3->rwstate; }

void SSL_CTX_set_tmp_rsa_callback(SSL_CTX *ctx,
                                  RSA *(*cb)(SSL *ssl, int is_export,
                                             int keylength)) {}

void SSL_set_tmp_rsa_callback(SSL *ssl, RSA *(*cb)(SSL *ssl, int is_export,
                                                   int keylength)) {}

void SSL_CTX_set_tmp_dh_callback(SSL_CTX *ctx,
                                 DH *(*cb)(SSL *ssl, int is_export,
                                           int keylength)) {}

void SSL_set_tmp_dh_callback(SSL *ssl, DH *(*cb)(SSL *ssl, int is_export,
                                                 int keylength)) {}

static int use_psk_identity_hint(char **out, const char *identity_hint) {
  if (identity_hint != NULL && strlen(identity_hint) > PSK_MAX_IDENTITY_LEN) {
    OPENSSL_PUT_ERROR(SSL, SSL_R_DATA_LENGTH_TOO_LONG);
    return 0;
  }

  // Clear currently configured hint, if any.
  OPENSSL_free(*out);
  *out = NULL;

  // Treat the empty hint as not supplying one. Plain PSK makes it possible to
  // send either no hint (omit ServerKeyExchange) or an empty hint, while
  // ECDHE_PSK can only spell empty hint. Having different capabilities is odd,
  // so we interpret empty and missing as identical.
  if (identity_hint != NULL && identity_hint[0] != '\0') {
    *out = BUF_strdup(identity_hint);
    if (*out == NULL) {
      return 0;
    }
  }

  return 1;
}

int SSL_CTX_use_psk_identity_hint(SSL_CTX *ctx, const char *identity_hint) {
  return use_psk_identity_hint(&ctx->psk_identity_hint, identity_hint);
}

int SSL_use_psk_identity_hint(SSL *ssl, const char *identity_hint) {
  if (!ssl->config) {
    return 0;
  }
  return use_psk_identity_hint(&ssl->config->psk_identity_hint, identity_hint);
}

const char *SSL_get_psk_identity_hint(const SSL *ssl) {
  if (ssl == NULL) {
    return NULL;
  }
  if (ssl->config == NULL) {
    assert(ssl->config);
    return NULL;
  }
  return ssl->config->psk_identity_hint;
}

const char *SSL_get_psk_identity(const SSL *ssl) {
  if (ssl == NULL) {
    return NULL;
  }
  SSL_SESSION *session = SSL_get_session(ssl);
  if (session == NULL) {
    return NULL;
  }
  return session->psk_identity;
}

void SSL_set_psk_client_callback(
    SSL *ssl, unsigned (*cb)(SSL *ssl, const char *hint, char *identity,
                             unsigned max_identity_len, uint8_t *psk,
                             unsigned max_psk_len)) {
  if (!ssl->config) {
    return;
  }
  ssl->config->psk_client_callback = cb;
}

void SSL_CTX_set_psk_client_callback(
    SSL_CTX *ctx, unsigned (*cb)(SSL *ssl, const char *hint, char *identity,
                                 unsigned max_identity_len, uint8_t *psk,
                                 unsigned max_psk_len)) {
  ctx->psk_client_callback = cb;
}

void SSL_set_psk_server_callback(
    SSL *ssl, unsigned (*cb)(SSL *ssl, const char *identity, uint8_t *psk,
                             unsigned max_psk_len)) {
  if (!ssl->config) {
    return;
  }
  ssl->config->psk_server_callback = cb;
}

void SSL_CTX_set_psk_server_callback(
    SSL_CTX *ctx, unsigned (*cb)(SSL *ssl, const char *identity,
                                 uint8_t *psk, unsigned max_psk_len)) {
  ctx->psk_server_callback = cb;
}

int SSL_set_dummy_pq_padding_size(SSL *ssl, size_t num_bytes) {
  if (!ssl->config) {
    return 0;
  }
  if (num_bytes > 0xffff) {
    return 0;
  }

  ssl->config->dummy_pq_padding_len = num_bytes;
  return 1;
}

int SSL_dummy_pq_padding_used(SSL *ssl) {
  if (ssl->server) {
    return 0;
  }

  return ssl->did_dummy_pq_padding;
}

void SSL_CTX_set_msg_callback(SSL_CTX *ctx,
                              void (*cb)(int write_p, int version,
                                         int content_type, const void *buf,
                                         size_t len, SSL *ssl, void *arg)) {
  ctx->msg_callback = cb;
}

void SSL_CTX_set_msg_callback_arg(SSL_CTX *ctx, void *arg) {
  ctx->msg_callback_arg = arg;
}

void SSL_set_msg_callback(SSL *ssl,
                          void (*cb)(int write_p, int version, int content_type,
                                     const void *buf, size_t len, SSL *ssl,
                                     void *arg)) {
  ssl->msg_callback = cb;
}

void SSL_set_msg_callback_arg(SSL *ssl, void *arg) {
  ssl->msg_callback_arg = arg;
}

void SSL_CTX_set_keylog_callback(SSL_CTX *ctx,
                                 void (*cb)(const SSL *ssl, const char *line)) {
  ctx->keylog_callback = cb;
}

void (*SSL_CTX_get_keylog_callback(const SSL_CTX *ctx))(const SSL *ssl,
                                                        const char *line) {
  return ctx->keylog_callback;
}

void SSL_CTX_set_current_time_cb(SSL_CTX *ctx,
                                 void (*cb)(const SSL *ssl,
                                            struct timeval *out_clock)) {
  ctx->current_time_cb = cb;
}

int SSL_is_init_finished(const SSL *ssl) {
  return !SSL_in_init(ssl);
}

int SSL_in_init(const SSL *ssl) {
  // This returns false once all the handshake state has been finalized, to
  // allow callbacks and getters based on SSL_in_init to return the correct
  // values.
  SSL_HANDSHAKE *hs = ssl->s3->hs.get();
  return hs != nullptr && !hs->handshake_finalized;
}

int SSL_in_false_start(const SSL *ssl) {
  if (ssl->s3->hs == NULL) {
    return 0;
  }
  return ssl->s3->hs->in_false_start;
}

int SSL_cutthrough_complete(const SSL *ssl) {
  return SSL_in_false_start(ssl);
}

void SSL_get_structure_sizes(size_t *ssl_size, size_t *ssl_ctx_size,
                             size_t *ssl_session_size) {
  *ssl_size = sizeof(SSL);
  *ssl_ctx_size = sizeof(SSL_CTX);
  *ssl_session_size = sizeof(SSL_SESSION);
}

int SSL_is_server(const SSL *ssl) { return ssl->server; }

int SSL_is_dtls(const SSL *ssl) { return ssl->method->is_dtls; }

void SSL_CTX_set_select_certificate_cb(
    SSL_CTX *ctx,
    enum ssl_select_cert_result_t (*cb)(const SSL_CLIENT_HELLO *)) {
  ctx->select_certificate_cb = cb;
}

void SSL_CTX_set_dos_protection_cb(SSL_CTX *ctx,
                                   int (*cb)(const SSL_CLIENT_HELLO *)) {
  ctx->dos_protection_cb = cb;
}

void SSL_set_renegotiate_mode(SSL *ssl, enum ssl_renegotiate_mode_t mode) {
  ssl->renegotiate_mode = mode;

  // Check if |ssl_can_renegotiate| has changed and the configuration may now be
  // shed. HTTP clients may initially allow renegotiation for HTTP/1.1, and then
  // disable after the handshake once the ALPN protocol is known to be HTTP/2.
  ssl_maybe_shed_handshake_config(ssl);
}

int SSL_get_ivs(const SSL *ssl, const uint8_t **out_read_iv,
                const uint8_t **out_write_iv, size_t *out_iv_len) {
  size_t write_iv_len;
  if (!ssl->s3->aead_read_ctx->GetIV(out_read_iv, out_iv_len) ||
      !ssl->s3->aead_write_ctx->GetIV(out_write_iv, &write_iv_len) ||
      *out_iv_len != write_iv_len) {
    return 0;
  }

  return 1;
}

static uint64_t be_to_u64(const uint8_t in[8]) {
  return (((uint64_t)in[0]) << 56) | (((uint64_t)in[1]) << 48) |
         (((uint64_t)in[2]) << 40) | (((uint64_t)in[3]) << 32) |
         (((uint64_t)in[4]) << 24) | (((uint64_t)in[5]) << 16) |
         (((uint64_t)in[6]) << 8) | ((uint64_t)in[7]);
}

uint64_t SSL_get_read_sequence(const SSL *ssl) {
  // TODO(davidben): Internally represent sequence numbers as uint64_t.
  if (SSL_is_dtls(ssl)) {
    // max_seq_num already includes the epoch.
    assert(ssl->d1->r_epoch == (ssl->d1->bitmap.max_seq_num >> 48));
    return ssl->d1->bitmap.max_seq_num;
  }
  return be_to_u64(ssl->s3->read_sequence);
}

uint64_t SSL_get_write_sequence(const SSL *ssl) {
  uint64_t ret = be_to_u64(ssl->s3->write_sequence);
  if (SSL_is_dtls(ssl)) {
    assert((ret >> 48) == 0);
    ret |= ((uint64_t)ssl->d1->w_epoch) << 48;
  }
  return ret;
}

uint16_t SSL_get_peer_signature_algorithm(const SSL *ssl) {
  // TODO(davidben): This checks the wrong session if there is a renegotiation
  // in progress.
  SSL_SESSION *session = SSL_get_session(ssl);
  if (session == NULL) {
    return 0;
  }

  return session->peer_signature_algorithm;
}

size_t SSL_get_client_random(const SSL *ssl, uint8_t *out, size_t max_out) {
  if (max_out == 0) {
    return sizeof(ssl->s3->client_random);
  }
  if (max_out > sizeof(ssl->s3->client_random)) {
    max_out = sizeof(ssl->s3->client_random);
  }
  OPENSSL_memcpy(out, ssl->s3->client_random, max_out);
  return max_out;
}

size_t SSL_get_server_random(const SSL *ssl, uint8_t *out, size_t max_out) {
  if (max_out == 0) {
    return sizeof(ssl->s3->server_random);
  }
  if (max_out > sizeof(ssl->s3->server_random)) {
    max_out = sizeof(ssl->s3->server_random);
  }
  OPENSSL_memcpy(out, ssl->s3->server_random, max_out);
  return max_out;
}

const SSL_CIPHER *SSL_get_pending_cipher(const SSL *ssl) {
  SSL_HANDSHAKE *hs = ssl->s3->hs.get();
  if (hs == NULL) {
    return NULL;
  }
  return hs->new_cipher;
}

void SSL_set_retain_only_sha256_of_client_certs(SSL *ssl, int enabled) {
  if (!ssl->config) {
    return;
  }
  ssl->config->retain_only_sha256_of_client_certs = !!enabled;
}

void SSL_CTX_set_retain_only_sha256_of_client_certs(SSL_CTX *ctx, int enabled) {
  ctx->retain_only_sha256_of_client_certs = !!enabled;
}

void SSL_CTX_set_grease_enabled(SSL_CTX *ctx, int enabled) {
  ctx->grease_enabled = !!enabled;
}

int32_t SSL_get_ticket_age_skew(const SSL *ssl) {
  return ssl->s3->ticket_age_skew;
}

void SSL_CTX_set_false_start_allowed_without_alpn(SSL_CTX *ctx, int allowed) {
  ctx->false_start_allowed_without_alpn = !!allowed;
}

int SSL_is_draft_downgrade(const SSL *ssl) { return ssl->s3->draft_downgrade; }

void SSL_set_shed_handshake_config(SSL *ssl, int enable) {
  if (!ssl->config) {
    return;
  }
  ssl->config->shed_handshake_config = !!enable;
}

int SSL_clear(SSL *ssl) {
  if (!ssl->config) {
    return 0;  // SSL_clear may not be used after shedding config.
  }

  // In OpenSSL, reusing a client |SSL| with |SSL_clear| causes the previously
  // established session to be offered the next time around. wpa_supplicant
  // depends on this behavior, so emulate it.
  UniquePtr<SSL_SESSION> session;
  if (!ssl->server && ssl->s3->established_session != NULL) {
    session.reset(ssl->s3->established_session.get());
    SSL_SESSION_up_ref(session.get());
  }

  // The ssl->d1->mtu is simultaneously configuration (preserved across
  // clear) and connection-specific state (gets reset).
  //
  // TODO(davidben): Avoid this.
  unsigned mtu = 0;
  if (ssl->d1 != NULL) {
    mtu = ssl->d1->mtu;
  }

  ssl->method->ssl_free(ssl);
  if (!ssl->method->ssl_new(ssl)) {
    return 0;
  }

  if (SSL_is_dtls(ssl) && (SSL_get_options(ssl) & SSL_OP_NO_QUERY_MTU)) {
    ssl->d1->mtu = mtu;
  }

  if (session != nullptr) {
    SSL_set_session(ssl, session.get());
  }

  return 1;
}

int SSL_CTX_sess_connect(const SSL_CTX *ctx) { return 0; }
int SSL_CTX_sess_connect_good(const SSL_CTX *ctx) { return 0; }
int SSL_CTX_sess_connect_renegotiate(const SSL_CTX *ctx) { return 0; }
int SSL_CTX_sess_accept(const SSL_CTX *ctx) { return 0; }
int SSL_CTX_sess_accept_renegotiate(const SSL_CTX *ctx) { return 0; }
int SSL_CTX_sess_accept_good(const SSL_CTX *ctx) { return 0; }
int SSL_CTX_sess_hits(const SSL_CTX *ctx) { return 0; }
int SSL_CTX_sess_cb_hits(const SSL_CTX *ctx) { return 0; }
int SSL_CTX_sess_misses(const SSL_CTX *ctx) { return 0; }
int SSL_CTX_sess_timeouts(const SSL_CTX *ctx) { return 0; }
int SSL_CTX_sess_cache_full(const SSL_CTX *ctx) { return 0; }

int SSL_num_renegotiations(const SSL *ssl) {
  return SSL_total_renegotiations(ssl);
}

int SSL_CTX_need_tmp_RSA(const SSL_CTX *ctx) { return 0; }
int SSL_need_tmp_RSA(const SSL *ssl) { return 0; }
int SSL_CTX_set_tmp_rsa(SSL_CTX *ctx, const RSA *rsa) { return 1; }
int SSL_set_tmp_rsa(SSL *ssl, const RSA *rsa) { return 1; }
void ERR_load_SSL_strings(void) {}
void SSL_load_error_strings(void) {}
int SSL_cache_hit(SSL *ssl) { return SSL_session_reused(ssl); }

int SSL_CTX_set_tmp_ecdh(SSL_CTX *ctx, const EC_KEY *ec_key) {
  if (ec_key == NULL || EC_KEY_get0_group(ec_key) == NULL) {
    OPENSSL_PUT_ERROR(SSL, ERR_R_PASSED_NULL_PARAMETER);
    return 0;
  }
  int nid = EC_GROUP_get_curve_name(EC_KEY_get0_group(ec_key));
  return SSL_CTX_set1_curves(ctx, &nid, 1);
}

int SSL_set_tmp_ecdh(SSL *ssl, const EC_KEY *ec_key) {
  if (ec_key == NULL || EC_KEY_get0_group(ec_key) == NULL) {
    OPENSSL_PUT_ERROR(SSL, ERR_R_PASSED_NULL_PARAMETER);
    return 0;
  }
  int nid = EC_GROUP_get_curve_name(EC_KEY_get0_group(ec_key));
  return SSL_set1_curves(ssl, &nid, 1);
}

void SSL_CTX_set_ticket_aead_method(SSL_CTX *ctx,
                                    const SSL_TICKET_AEAD_METHOD *aead_method) {
  ctx->ticket_aead_method = aead_method;
}