text: /* 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
  
  
  BSSL_NAMESPACE_BEGIN
  
  // |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_ERROR_NONE;
    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;
  }
  
  bool ssl_can_write(const SSL *ssl) {
    return !SSL_in_init(ssl) || ssl->s3->hs->can_early_write;
  }
  
  bool 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.get();
    // 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.get() ||
        (!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) {
        UniquePtr<SSL_SESSION> ref = UpRef(ssl->s3->established_session);
        if (ctx->new_session_cb(ssl, ref.get())) {
          // |new_session_cb|'s return value signals whether it took ownership.
          ref.release();
        }
      }
    }
  
    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 bool cbb_add_hex(CBB *cbb, Span<const uint8_t> in) {
    static const char hextable[] = "0123456789abcdef";
    uint8_t *out;
  
    if (!CBB_add_space(cbb, &out, in.size() * 2)) {
      return false;
    }
  
    for (uint8_t b : in) {
      *(out++) = (uint8_t)hextable[b >> 4];
      *(out++) = (uint8_t)hextable[b & 0xf];
    }
  
    return true;
  }
  
  bool ssl_log_secret(const SSL *ssl, const char *label,
                      Span<const uint8_t> secret) {
    if (ssl->ctx->keylog_callback == NULL) {
      return true;
    }
  
    ScopedCBB cbb;
    Array<uint8_t> line;
    if (!CBB_init(cbb.get(), strlen(label) + 1 + SSL3_RANDOM_SIZE * 2 + 1 +
                                 secret.size() * 2 + 1) ||
        !CBB_add_bytes(cbb.get(), reinterpret_cast<const uint8_t *>(label),
                       strlen(label)) ||
        !CBB_add_u8(cbb.get(), ' ') ||
        !cbb_add_hex(cbb.get(), ssl->s3->client_random) ||
        !CBB_add_u8(cbb.get(), ' ') ||
        !cbb_add_hex(cbb.get(), secret) ||
        !CBB_add_u8(cbb.get(), 0 /* NUL */) ||
        !CBBFinishArray(cbb.get(), &line)) {
      return false;
    }
  
    ssl->ctx->keylog_callback(ssl, reinterpret_cast<const char *>(line.data()));
    return true;
  }
  
  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(const 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(),
                      const_cast<SSL *>(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.get(), 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;
    }
  
    if (ssl_protocol_version(ssl) >= 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:
      case ssl_renegotiate_explicit:
        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;
    }
  
    ssl->config.reset();
  }
  
  void SSL_set_handoff_mode(SSL *ssl, bool on) {
    if (!ssl->config) {
      return;
    }
    ssl->config->handoff = on;
  }
  
  bool SSL_get_traffic_secrets(const SSL *ssl,
                               Span<const uint8_t> *out_read_traffic_secret,
                               Span<const uint8_t> *out_write_traffic_secret) {
    if (SSL_version(ssl) < TLS1_3_VERSION) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SSL_VERSION);
      return false;
    }
  
    if (!ssl->s3->initial_handshake_complete) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_HANDSHAKE_NOT_COMPLETE);
      return false;
    }
  
    *out_read_traffic_secret = Span<const uint8_t>(
        ssl->s3->read_traffic_secret, ssl->s3->read_traffic_secret_len);
    *out_write_traffic_secret = Span<const uint8_t>(
        ssl->s3->write_traffic_secret, ssl->s3->write_traffic_secret_len);
  
    return true;
  }
  
  BSSL_NAMESPACE_END
  
  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) {
    return ssl_hash_session_id(
        MakeConstSpan(sess->session_id, sess->session_id_length));
  }
  
  static int ssl_session_cmp(const SSL_SESSION *a, const SSL_SESSION *b) {
    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_st::ssl_ctx_st(const SSL_METHOD *ssl_method)
      : method(ssl_method->method),
        x509_method(ssl_method->x509_method),
        retain_only_sha256_of_client_certs(false),
        quiet_shutdown(false),
        ocsp_stapling_enabled(false),
        signed_cert_timestamps_enabled(false),
        channel_id_enabled(false),
        grease_enabled(false),
        allow_unknown_alpn_protos(false),
        false_start_allowed_without_alpn(false),
        handoff(false),
        enable_early_data(false) {
    CRYPTO_MUTEX_init(&lock);
    CRYPTO_new_ex_data(&ex_data);
  }
  
  ssl_ctx_st::~ssl_ctx_st() {
    // Free the internal session cache. Note that this calls the caller-supplied
    // remove callback, so we must do it before clearing ex_data. (See ticket
    // [openssl.org #212].)
    SSL_CTX_flush_sessions(this, 0);
  
    CRYPTO_free_ex_data(&g_ex_data_class_ssl_ctx, this, &ex_data);
  
    CRYPTO_MUTEX_cleanup(&lock);
    lh_SSL_SESSION_free(sessions);
    x509_method->ssl_ctx_free(this);
  }
  
  SSL_CTX *SSL_CTX_new(const SSL_METHOD *method) {
    if (method == NULL) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_NULL_SSL_METHOD_PASSED);
      return nullptr;
    }
  
    UniquePtr<SSL_CTX> ret = MakeUnique<SSL_CTX>(method);
    if (!ret) {
      return nullptr;
    }
  
    ret->cert = MakeUnique<CERT>(method->x509_method);
    ret->sessions = lh_SSL_SESSION_new(ssl_session_hash, ssl_session_cmp);
    ret->client_CA.reset(sk_CRYPTO_BUFFER_new_null());
    if (ret->cert == nullptr ||
        ret->sessions == nullptr ||
        ret->client_CA == nullptr ||
        !ret->x509_method->ssl_ctx_new(ret.get())) {
      return nullptr;
    }
  
    if (!SSL_CTX_set_strict_cipher_list(ret.get(), SSL_DEFAULT_CIPHER_LIST) ||
        // Lock the SSL_CTX to the specified version, for compatibility with
        // legacy uses of SSL_METHOD.
        !SSL_CTX_set_max_proto_version(ret.get(), method->version) ||
        !SSL_CTX_set_min_proto_version(ret.get(), method->version)) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
      return nullptr;
    }
  
    return ret.release();
  }
  
  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;
    }
  
    ctx->~ssl_ctx_st();
    OPENSSL_free(ctx);
  }
  
  ssl_st::ssl_st(SSL_CTX *ctx_arg)
      : method(ctx_arg->method),
        max_send_fragment(ctx_arg->max_send_fragment),
        msg_callback(ctx_arg->msg_callback),
        msg_callback_arg(ctx_arg->msg_callback_arg),
        ctx(UpRef(ctx_arg)),
        session_ctx(UpRef(ctx_arg)),
        options(ctx->options),
        mode(ctx->mode),
        max_cert_list(ctx->max_cert_list),
        server(false),
        quiet_shutdown(ctx->quiet_shutdown),
        enable_early_data(ctx->enable_early_data) {
    CRYPTO_new_ex_data(&ex_data);
  }
  
  ssl_st::~ssl_st() {
    CRYPTO_free_ex_data(&g_ex_data_class_ssl, this, &ex_data);
    // |config| refers to |this|, so we must release it earlier.
    config.reset();
    if (method != NULL) {
      method->ssl_free(this);
    }
  }
  
  SSL *SSL_new(SSL_CTX *ctx) {
    if (ctx == nullptr) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_NULL_SSL_CTX);
      return nullptr;
    }
  
    UniquePtr<SSL> ssl = MakeUnique<SSL>(ctx);
    if (ssl == nullptr) {
      return nullptr;
    }
  
    ssl->config = MakeUnique<SSL_CONFIG>(ssl.get());
    if (ssl->config == nullptr) {
      return nullptr;
    }
    ssl->config->conf_min_version = ctx->conf_min_version;
    ssl->config->conf_max_version = ctx->conf_max_version;
  
    ssl->config->cert = ssl_cert_dup(ctx->cert.get());
    if (ssl->config->cert == nullptr) {
      return nullptr;
    }
  
    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;
  
    if (!ssl->config->supported_group_list.CopyFrom(ctx->supported_group_list) ||
        !ssl->config->alpn_client_proto_list.CopyFrom(
            ctx->alpn_client_proto_list) ||
        !ssl->config->verify_sigalgs.CopyFrom(ctx->verify_sigalgs)) {
      return nullptr;
    }
  
    if (ctx->psk_identity_hint) {
      ssl->config->psk_identity_hint.reset(
          OPENSSL_strdup(ctx->psk_identity_hint.get()));
      if (ssl->config->psk_identity_hint == nullptr) {
        return nullptr;
      }
    }
    ssl->config->psk_client_callback = ctx->psk_client_callback;
    ssl->config->psk_server_callback = ctx->psk_server_callback;
  
    ssl->config->channel_id_enabled = ctx->channel_id_enabled;
    ssl->config->channel_id_private = UpRef(ctx->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;
    ssl->quic_method = ctx->quic_method;
  
    if (!ssl->method->ssl_new(ssl.get()) ||
        !ssl->ctx->x509_method->ssl_new(ssl->s3->hs.get())) {
      return nullptr;
    }
  
    return ssl.release();
  }
  
  SSL_CONFIG::SSL_CONFIG(SSL *ssl_arg)
      : ssl(ssl_arg),
        ech_grease_enabled(false),
        signed_cert_timestamps_enabled(false),
        ocsp_stapling_enabled(false),
        channel_id_enabled(false),
        enforce_rsa_key_usage(false),
        retain_only_sha256_of_client_certs(false),
        handoff(false),
        shed_handshake_config(false),
        jdk11_workaround(false),
        quic_use_legacy_codepoint(true) {
    assert(ssl);
  }
  
  SSL_CONFIG::~SSL_CONFIG() {
    if (ssl->ctx != nullptr) {
      ssl->ctx->x509_method->ssl_config_free(this);
    }
  }
  
  void SSL_free(SSL *ssl) {
    Delete(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) {
    ssl->rbio.reset(rbio);
  }
  
  void SSL_set0_wbio(SSL *ssl, BIO *wbio) {
    ssl->wbio.reset(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.get(); }
  
  BIO *SSL_get_wbio(const SSL *ssl) { return ssl->wbio.get(); }
  
  size_t SSL_quic_max_handshake_flight_len(const SSL *ssl,
                                           enum ssl_encryption_level_t level) {
    // Limits flights to 16K by default when there are no large
    // (certificate-carrying) messages.
    static const size_t kDefaultLimit = 16384;
  
    switch (level) {
      case ssl_encryption_initial:
        return kDefaultLimit;
      case ssl_encryption_early_data:
        // QUIC does not send EndOfEarlyData.
        return 0;
      case ssl_encryption_handshake:
        if (ssl->server) {
          // Servers may receive Certificate message if configured to request
          // client certificates.
          if (!!(ssl->config->verify_mode & SSL_VERIFY_PEER) &&
              ssl->max_cert_list > kDefaultLimit) {
            return ssl->max_cert_list;
          }
        } else {
          // Clients may receive both Certificate message and a CertificateRequest
          // message.
          if (2*ssl->max_cert_list > kDefaultLimit) {
            return 2*ssl->max_cert_list;
          }
        }
        return kDefaultLimit;
      case ssl_encryption_application:
        // Note there is not actually a bound on the number of NewSessionTickets
        // one may send in a row. This level may need more involved flow
        // control. See https://github.com/quicwg/base-drafts/issues/1834.
        return kDefaultLimit;
    }
  
    return 0;
  }
  
  enum ssl_encryption_level_t SSL_quic_read_level(const SSL *ssl) {
    return ssl->s3->read_level;
  }
  
  enum ssl_encryption_level_t SSL_quic_write_level(const SSL *ssl) {
    return ssl->s3->write_level;
  }
  
  int SSL_provide_quic_data(SSL *ssl, enum ssl_encryption_level_t level,
                            const uint8_t *data, size_t len) {
    if (ssl->quic_method == nullptr) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
      return 0;
    }
  
    if (level != ssl->s3->read_level) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_ENCRYPTION_LEVEL_RECEIVED);
      return 0;
    }
  
    size_t new_len = (ssl->s3->hs_buf ? ssl->s3->hs_buf->length : 0) + len;
    if (new_len < len ||
        new_len > SSL_quic_max_handshake_flight_len(ssl, level)) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_EXCESSIVE_MESSAGE_SIZE);
      return 0;
    }
  
    return tls_append_handshake_data(ssl, MakeConstSpan(data, len));
  }
  
  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.
    }
  
    ssl->s3->renegotiate_pending = true;
    if (ssl->renegotiate_mode == ssl_renegotiate_explicit) {
      return 1;  // Handle it later.
    }
  
    if (!SSL_renegotiate(ssl)) {
      ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_NO_RENEGOTIATION);
      return 0;
    }
  
    return 1;
  }
  
  int SSL_process_quic_post_handshake(SSL *ssl) {
    ssl_reset_error_state(ssl);
  
    if (SSL_in_init(ssl)) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
      return 0;
    }
  
    // Replay post-handshake message errors.
    if (!check_read_error(ssl)) {
      return 0;
    }
  
    // Process any buffered post-handshake messages.
    SSLMessage msg;
    while (ssl->method->get_message(ssl, &msg)) {
      // Handle the post-handshake message and try again.
      if (!ssl_do_post_handshake(ssl, msg)) {
        ssl_set_read_error(ssl);
        return 0;
      }
      ssl->method->next_message(ssl);
    }
  
    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()) {
      if (ssl->s3->renegotiate_pending) {
        ssl->s3->rwstate = SSL_ERROR_WANT_RENEGOTIATE;
        return -1;
      }
  
      // 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) {
    if (ssl->quic_method != nullptr) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
      return 0;
    }
  
    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->quic_method != nullptr) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
      return 0;
    }
  
    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_key_update(SSL *ssl, int request_type) {
    ssl_reset_error_state(ssl);
  
    if (ssl->do_handshake == NULL) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_UNINITIALIZED);
      return 0;
    }
  
    if (ssl->ctx->quic_method != nullptr) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
      return 0;
    }
  
    if (!ssl->s3->initial_handshake_complete) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_HANDSHAKE_NOT_COMPLETE);
      return 0;
    }
  
    if (ssl_protocol_version(ssl) < TLS1_3_VERSION) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SSL_VERSION);
      return 0;
    }
  
    if (!ssl->s3->key_update_pending &&
        !tls13_add_key_update(ssl, request_type)) {
      return 0;
    }
  
    return 1;
  }
  
  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_impl(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 {
        // Process records until an error, close_notify, or application data.
        if (ssl_read_impl(ssl) > 0) {
          // We received some unexpected application data.
          OPENSSL_PUT_ERROR(SSL, SSL_R_APPLICATION_DATA_ON_SHUTDOWN);
          return -1;
        }
        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_impl(ssl, SSL3_AL_FATAL, alert);
  }
  
  int SSL_set_quic_transport_params(SSL *ssl, const uint8_t *params,
                                    size_t params_len) {
    return ssl->config && ssl->config->quic_transport_params.CopyFrom(
                              MakeConstSpan(params, params_len));
  }
  
  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();
  }
  
  int SSL_set_quic_early_data_context(SSL *ssl, const uint8_t *context,
                                      size_t context_len) {
    return ssl->config && ssl->config->quic_early_data_context.CopyFrom(
                              MakeConstSpan(context, context_len));
  }
  
  void SSL_CTX_set_early_data_enabled(SSL_CTX *ctx, int enabled) {
    ctx->enable_early_data = !!enabled;
  }
  
  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;
  }
  
  enum ssl_early_data_reason_t SSL_get_early_data_reason(const SSL *ssl) {
    return ssl->s3->early_data_reason;
  }
  
  const char *SSL_early_data_reason_string(enum ssl_early_data_reason_t reason) {
    switch (reason) {
      case ssl_early_data_unknown:
        return "unknown";
      case ssl_early_data_disabled:
        return "disabled";
      case ssl_early_data_accepted:
        return "accepted";
      case ssl_early_data_protocol_version:
        return "protocol_version";
      case ssl_early_data_peer_declined:
        return "peer_declined";
      case ssl_early_data_no_session_offered:
        return "no_session_offered";
      case ssl_early_data_session_not_resumed:
        return "session_not_resumed";
      case ssl_early_data_unsupported_for_session:
        return "unsupported_for_session";
      case ssl_early_data_hello_retry_request:
        return "hello_retry_request";
      case ssl_early_data_alpn_mismatch:
        return "alpn_mismatch";
      case ssl_early_data_channel_id:
        return "channel_id";
      case ssl_early_data_token_binding:
        return "token_binding";
      case ssl_early_data_ticket_age_skew:
        return "ticket_age_skew";
      case ssl_early_data_quic_parameter_mismatch:
        return "quic_parameter_mismatch";
      case ssl_early_data_alps_mismatch:
        return "alps_mismatch";
    }
  
    return nullptr;
  }
  
  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_ERROR_PENDING_SESSION:
      case SSL_ERROR_PENDING_CERTIFICATE:
      case SSL_ERROR_HANDOFF:
      case SSL_ERROR_HANDBACK:
      case SSL_ERROR_WANT_X509_LOOKUP:
      case SSL_ERROR_WANT_CHANNEL_ID_LOOKUP:
      case SSL_ERROR_WANT_PRIVATE_KEY_OPERATION:
      case SSL_ERROR_PENDING_TICKET:
      case SSL_ERROR_EARLY_DATA_REJECTED:
      case SSL_ERROR_WANT_CERTIFICATE_VERIFY:
      case SSL_ERROR_WANT_RENEGOTIATE:
      case SSL_ERROR_HANDSHAKE_HINTS_READY:
        return ssl->s3->rwstate;
  
      case SSL_ERROR_WANT_READ: {
        if (ssl->quic_method) {
          return SSL_ERROR_WANT_READ;
        }
        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_ERROR_WANT_WRITE: {
        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;
      }
    }
  
    return SSL_ERROR_SYSCALL;
  }
  
  const char *SSL_error_description(int err) {
    switch (err) {
      case SSL_ERROR_NONE:
        return "NONE";
      case SSL_ERROR_SSL:
        return "SSL";
      case SSL_ERROR_WANT_READ:
        return "WANT_READ";
      case SSL_ERROR_WANT_WRITE:
        return "WANT_WRITE";
      case SSL_ERROR_WANT_X509_LOOKUP:
        return "WANT_X509_LOOKUP";
      case SSL_ERROR_SYSCALL:
        return "SYSCALL";
      case SSL_ERROR_ZERO_RETURN:
        return "ZERO_RETURN";
      case SSL_ERROR_WANT_CONNECT:
        return "WANT_CONNECT";
      case SSL_ERROR_WANT_ACCEPT:
        return "WANT_ACCEPT";
      case SSL_ERROR_WANT_CHANNEL_ID_LOOKUP:
        return "WANT_CHANNEL_ID_LOOKUP";
      case SSL_ERROR_PENDING_SESSION:
        return "PENDING_SESSION";
      case SSL_ERROR_PENDING_CERTIFICATE:
        return "PENDING_CERTIFICATE";
      case SSL_ERROR_WANT_PRIVATE_KEY_OPERATION:
        return "WANT_PRIVATE_KEY_OPERATION";
      case SSL_ERROR_PENDING_TICKET:
        return "PENDING_TICKET";
      case SSL_ERROR_EARLY_DATA_REJECTED:
        return "EARLY_DATA_REJECTED";
      case SSL_ERROR_WANT_CERTIFICATE_VERIFY:
        return "WANT_CERTIFICATE_VERIFY";
      case SSL_ERROR_HANDOFF:
        return "HANDOFF";
      case SSL_ERROR_HANDBACK:
        return "HANDBACK";
      case SSL_ERROR_HANDSHAKE_HINTS_READY:
        return "HANDSHAKE_HINTS_READY";
      default:
        return nullptr;
    }
  }
  
  void SSL_set_enable_ech_grease(SSL *ssl, int enable) {
    if (!ssl->config) {
      return;
    }
    ssl->config->ech_grease_enabled = !!enable;
  }
  
  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 TLS 1.3.
    if (!ssl->s3->initial_handshake_complete ||
        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.get(), 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.get(), 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.get());
  }
  
  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_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_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; }
  
  int SSL_CTX_set_read_ahead(SSL_CTX *ctx, int yes) { return 1; }
  
  int SSL_set_read_ahead(SSL *ssl, int yes) { return 1; }
  
  int SSL_pending(const SSL *ssl) {
    return static_cast<int>(ssl->s3->pending_app_data.size());
  }
  
  int SSL_CTX_check_private_key(const SSL_CTX *ctx) {
    return ssl_cert_check_private_key(ctx->cert.get(),
                                      ctx->cert->privatekey.get());
  }
  
  int SSL_check_private_key(const SSL *ssl) {
    if (!ssl->config) {
      return 0;
    }
    return ssl_cert_check_private_key(ssl->config->cert.get(),
                                      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.
    if (!ssl->s3->renegotiate_pending) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
      return 0;
    }
  
    if (!ssl_can_renegotiate(ssl)) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_NO_RENEGOTIATION);
      return 0;
    }
  
    // 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.
    if (!ssl->s3->write_buffer.empty() ||
        ssl->s3->write_shutdown != ssl_shutdown_none) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_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->renegotiate_pending = false;
    ssl->s3->total_renegotiations++;
    return 1;
  }
  
  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->ticket_key_current->name, 16);
    OPENSSL_memcpy(out_bytes + 16, ctx->ticket_key_current->hmac_key, 16);
    OPENSSL_memcpy(out_bytes + 32, ctx->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;
    }
    auto key = MakeUnique<TicketKey>();
    if (!key) {
      return 0;
    }
    const uint8_t *in_bytes = reinterpret_cast<const uint8_t *>(in);
    OPENSSL_memcpy(key->name, in_bytes, 16);
    OPENSSL_memcpy(key->hmac_key, in_bytes + 16, 16);
    OPENSSL_memcpy(key->aes_key, in_bytes + 32, 16);
    // Disable automatic key rotation for manually-configured keys. This is now
    // the caller's responsibility.
    key->next_rotation_tv_sec = 0;
    ctx->ticket_key_current = std::move(key);
    ctx->ticket_key_prev.reset();
    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->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,
                           MakeConstSpan(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,
                           MakeConstSpan(curves, curves_len));
  }
  
  int SSL_CTX_set1_curves_list(SSL_CTX *ctx, const char *curves) {
    return tls1_set_curves_list(&ctx->supported_group_list, 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, 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->hostname != nullptr) {
      return ssl->hostname.get();
    }
  
    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.get());
    *out_len = CRYPTO_BUFFER_len(session->signed_cert_timestamp_list.get());
  }
  
  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.get());
    *out_len = CRYPTO_BUFFER_len(session->ocsp_response.get());
  }
  
  int SSL_set_tlsext_host_name(SSL *ssl, const char *name) {
    ssl->hostname.reset();
    if (name == nullptr) {
      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->hostname.reset(OPENSSL_strdup(name));
    if (ssl->hostname == nullptr) {
      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->servername_callback = callback;
    return 1;
  }
  
  int SSL_CTX_set_tlsext_servername_arg(SSL_CTX *ctx, void *arg) {
    ctx->servername_arg = arg;
    return 1;
  }
  
  SSL_ECH_SERVER_CONFIG_LIST *SSL_ECH_SERVER_CONFIG_LIST_new() {
    return New<SSL_ECH_SERVER_CONFIG_LIST>();
  }
  
  void SSL_ECH_SERVER_CONFIG_LIST_up_ref(SSL_ECH_SERVER_CONFIG_LIST *configs) {
    CRYPTO_refcount_inc(&configs->references);
  }
  
  void SSL_ECH_SERVER_CONFIG_LIST_free(SSL_ECH_SERVER_CONFIG_LIST *configs) {
    if (configs == nullptr ||
        !CRYPTO_refcount_dec_and_test_zero(&configs->references)) {
      return;
    }
  
    configs->~ssl_ech_server_config_list_st();
    OPENSSL_free(configs);
  }
  
  int SSL_ECH_SERVER_CONFIG_LIST_add(SSL_ECH_SERVER_CONFIG_LIST *configs,
                                     int is_retry_config,
                                     const uint8_t *ech_config,
                                     size_t ech_config_len,
                                     const uint8_t *private_key,
                                     size_t private_key_len) {
    ECHServerConfig parsed_config;
    if (!parsed_config.Init(MakeConstSpan(ech_config, ech_config_len),
                            MakeConstSpan(private_key, private_key_len),
                            !!is_retry_config)) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
      return 0;
    }
    if (!configs->configs.Push(std::move(parsed_config))) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
      return 0;
    }
    return 1;
  }
  
  int SSL_CTX_set1_ech_server_config_list(SSL_CTX *ctx,
                                          SSL_ECH_SERVER_CONFIG_LIST *list) {
    bool has_retry_config = false;
    for (const bssl::ECHServerConfig &config : list->configs) {
      if (config.is_retry_config()) {
        has_retry_config = true;
        break;
      }
    }
    if (!has_retry_config) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_ECH_SERVER_WOULD_HAVE_NO_RETRY_CONFIGS);
      return 0;
    }
    UniquePtr<SSL_ECH_SERVER_CONFIG_LIST> owned_list = UpRef(list);
    MutexWriteLock lock(&ctx->lock);
    ctx->ech_server_config_list.swap(owned_list);
    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) {
    // Note this function's return value is backwards.
    auto span = MakeConstSpan(protos, protos_len);
    if (!span.empty() && !ssl_is_valid_alpn_list(span)) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_ALPN_PROTOCOL_LIST);
      return 1;
    }
    return ctx->alpn_client_proto_list.CopyFrom(span) ? 0 : 1;
  }
  
  int SSL_set_alpn_protos(SSL *ssl, const uint8_t *protos, unsigned protos_len) {
    // Note this function's return value is backwards.
    if (!ssl->config) {
      return 1;
    }
    auto span = MakeConstSpan(protos, protos_len);
    if (!span.empty() && !ssl_is_valid_alpn_list(span)) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_ALPN_PROTOCOL_LIST);
      return 1;
    }
    return ssl->config->alpn_client_proto_list.CopyFrom(span) ? 0 : 1;
  }
  
  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.data();
      *out_len = ssl->s3->hs->early_session->early_alpn.size();
    } 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;
  }
  
  int SSL_add_application_settings(SSL *ssl, const uint8_t *proto,
                                   size_t proto_len, const uint8_t *settings,
                                   size_t settings_len) {
    if (!ssl->config) {
      return 0;
    }
    ALPSConfig config;
    if (!config.protocol.CopyFrom(MakeConstSpan(proto, proto_len)) ||
        !config.settings.CopyFrom(MakeConstSpan(settings, settings_len)) ||
        !ssl->config->alps_configs.Push(std::move(config))) {
      return 0;
    }
    return 1;
  }
  
  void SSL_get0_peer_application_settings(const SSL *ssl,
                                          const uint8_t **out_data,
                                          size_t *out_len) {
    const SSL_SESSION *session = SSL_get_session(ssl);
    Span<const uint8_t> settings =
        session ? session->peer_application_settings : Span<const uint8_t>();
    *out_data = settings.data();
    *out_len = settings.size();
  }
  
  int SSL_has_application_settings(const SSL *ssl) {
    const SSL_SESSION *session = SSL_get_session(ssl);
    return session && session->has_application_settings;
  }
  
  int SSL_CTX_add_cert_compression_alg(SSL_CTX *ctx, uint16_t alg_id,
                                       ssl_cert_compression_func_t compress,
                                       ssl_cert_decompression_func_t decompress) {
    assert(compress != nullptr || decompress != nullptr);
  
    for (const auto &alg : ctx->cert_compression_algs) {
      if (alg.alg_id == alg_id) {
        return 0;
      }
    }
  
    CertCompressionAlg alg;
    alg.alg_id = alg_id;
    alg.compress = compress;
    alg.decompress = decompress;
    return ctx->cert_compression_algs.Push(alg);
  }
  
  void SSL_CTX_set_tls_channel_id_enabled(SSL_CTX *ctx, int enabled) {
    ctx->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->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;
    }
  
    ctx->channel_id_private = UpRef(private_key);
    ctx->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;
    }
  
    ssl->config->channel_id_private = UpRef(private_key);
    ssl->config->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->channel_id_valid) {
      return 0;
    }
    OPENSSL_memcpy(out, ssl->s3->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;
    }
    return ssl->config->token_binding_params.CopyFrom(MakeConstSpan(params, len));
  }
  
  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(const SSL *ssl, const uint8_t **out_types) {
    Span<const uint8_t> types;
    if (!ssl->server && ssl->s3->hs != nullptr) {
      types = ssl->s3->hs->certificate_types;
    }
    *out_types = types.data();
    return types.size();
  }
  
  size_t SSL_get0_peer_verify_algorithms(const SSL *ssl,
                                         const uint16_t **out_sigalgs) {
    Span<const uint16_t> sigalgs;
    if (ssl->s3->hs != nullptr) {
      sigalgs = ssl->s3->hs->peer_sigalgs;
    }
    *out_sigalgs = sigalgs.data();
    return sigalgs.size();
  }
  
  size_t SSL_get0_peer_delegation_algorithms(const SSL *ssl,
                                             const uint16_t **out_sigalgs){
    Span<const uint16_t> sigalgs;
    if (ssl->s3->hs != nullptr) {
      sigalgs = ssl->s3->hs->peer_delegated_credential_sigalgs;
    }
    *out_sigalgs = sigalgs.data();
    return sigalgs.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) {
    const SSL_SESSION *session = SSL_get_session(ssl);
    return session == nullptr ? nullptr : session->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.get(); }
  
  SSL_CTX *SSL_set_SSL_CTX(SSL *ssl, SSL_CTX *ctx) {
    if (!ssl->config) {
      return NULL;
    }
    if (ssl->ctx.get() == ctx) {
      return ssl->ctx.get();
    }
  
    // One cannot change the X.509 callbacks during a connection.
    if (ssl->ctx->x509_method != ctx->x509_method) {
      assert(0);
      return NULL;
    }
  
    UniquePtr<CERT> new_cert = ssl_cert_dup(ctx->cert.get());
    if (!new_cert) {
      return nullptr;
    }
  
    ssl->config->cert = std::move(new_cert);
    ssl->ctx = UpRef(ctx);
    ssl->enable_early_data = ssl->ctx->enable_early_data;
  
    return ssl->ctx.get();
  }
  
  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_shared_sigalgs(SSL *ssl, int idx, int *psign, int *phash,
                             int *psignandhash, uint8_t *rsig, uint8_t *rhash) {
    return 0;
  }
  
  int SSL_CTX_set_quic_method(SSL_CTX *ctx, const SSL_QUIC_METHOD *quic_method) {
    if (ctx->method->is_dtls) {
      return 0;
    }
    ctx->quic_method = quic_method;
    return 1;
  }
  
  int SSL_set_quic_method(SSL *ssl, const SSL_QUIC_METHOD *quic_method) {
    if (ssl->method->is_dtls) {
      return 0;
    }
    ssl->quic_method = quic_method;
    return 1;
  }
  
  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(UniquePtr<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.
    out->reset();
  
    // 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->reset(OPENSSL_strdup(identity_hint));
      if (*out == nullptr) {
        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.get();
  }
  
  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.get();
  }
  
  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;
  }
  
  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);
  }
  
  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_CTX_set_reverify_on_resume(SSL_CTX *ctx, int enabled) {
    ctx->reverify_on_resume = !!enabled;
  }
  
  void SSL_set_enforce_rsa_key_usage(SSL *ssl, int enabled) {
    if (!ssl->config) {
      return;
    }
    ssl->config->enforce_rsa_key_usage = !!enabled;
  }
  
  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_used_hello_retry_request(const SSL *ssl) {
    return ssl->s3->used_hello_retry_request;
  }
  
  void SSL_set_shed_handshake_config(SSL *ssl, int enable) {
    if (!ssl->config) {
      return;
    }
    ssl->config->shed_handshake_config = !!enable;
  }
  
  void SSL_set_jdk11_workaround(SSL *ssl, int enable) {
    if (!ssl->config) {
      return;
    }
    ssl->config->jdk11_workaround = !!enable;
  }
  
  void SSL_set_quic_use_legacy_codepoint(SSL *ssl, int use_legacy) {
    if (!ssl->config) {
      return;
    }
    ssl->config->quic_use_legacy_codepoint = !!use_legacy;
  }
  
  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 = UpRef(ssl->s3->established_session);
    }
  
    // 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;
  }
  
  SSL_SESSION *SSL_process_tls13_new_session_ticket(SSL *ssl, const uint8_t *buf,
                                                    size_t buf_len) {
    if (SSL_in_init(ssl) ||
        ssl_protocol_version(ssl) != TLS1_3_VERSION ||
        ssl->server) {
      // Only TLS 1.3 clients are supported.
      OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
      return nullptr;
    }
  
    CBS cbs, body;
    CBS_init(&cbs, buf, buf_len);
    uint8_t type;
    if (!CBS_get_u8(&cbs, &type) ||
        !CBS_get_u24_length_prefixed(&cbs, &body) ||
        CBS_len(&cbs) != 0) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
      return nullptr;
    }
  
    UniquePtr<SSL_SESSION> session = tls13_create_session_with_ticket(ssl, &body);
    if (!session) {
      // |tls13_create_session_with_ticket| puts the correct error.
      return nullptr;
    }
    return session.release();
  }
  
  int SSL_set_tlsext_status_type(SSL *ssl, int type) {
    if (!ssl->config) {
      return 0;
    }
    ssl->config->ocsp_stapling_enabled = type == TLSEXT_STATUSTYPE_ocsp;
    return 1;
  }
  
  int SSL_get_tlsext_status_type(const SSL *ssl) {
    if (ssl->server) {
      SSL_HANDSHAKE *hs = ssl->s3->hs.get();
      return hs != nullptr && hs->ocsp_stapling_requested
          ? TLSEXT_STATUSTYPE_ocsp
          : TLSEXT_STATUSTYPE_nothing;
    }
  
    return ssl->config != nullptr && ssl->config->ocsp_stapling_enabled
               ? TLSEXT_STATUSTYPE_ocsp
               : TLSEXT_STATUSTYPE_nothing;
  }
  
  int SSL_set_tlsext_status_ocsp_resp(SSL *ssl, uint8_t *resp, size_t resp_len) {
    if (SSL_set_ocsp_response(ssl, resp, resp_len)) {
      OPENSSL_free(resp);
      return 1;
    }
    return 0;
  }
  
  size_t SSL_get_tlsext_status_ocsp_resp(const SSL *ssl, const uint8_t **out) {
    size_t ret;
    SSL_get0_ocsp_response(ssl, out, &ret);
    return ret;
  }
  
  int SSL_CTX_set_tlsext_status_cb(SSL_CTX *ctx,
                                   int (*callback)(SSL *ssl, void *arg)) {
    ctx->legacy_ocsp_callback = callback;
    return 1;
  }
  
  int SSL_CTX_set_tlsext_status_arg(SSL_CTX *ctx, void *arg) {
    ctx->legacy_ocsp_callback_arg = arg;
    return 1;
  }
  