// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/socket/client_socket_pool_manager.h"

#include <memory>

#include "base/logging.h"
#include "base/strings/stringprintf.h"
#include "net/base/load_flags.h"
#include "net/http/http_proxy_client_socket_pool.h"
#include "net/http/http_request_info.h"
#include "net/http/http_stream_factory.h"
#include "net/proxy_resolution/proxy_info.h"
#include "net/socket/client_socket_handle.h"
#include "net/socket/client_socket_pool.h"
#include "net/socket/socks_client_socket_pool.h"
#include "net/socket/ssl_client_socket_pool.h"
#include "net/socket/transport_client_socket_pool.h"
#include "net/ssl/ssl_config.h"

namespace net {

namespace {

// Limit of sockets of each socket pool.
int g_max_sockets_per_pool[] = {
  256,  // NORMAL_SOCKET_POOL
  256   // WEBSOCKET_SOCKET_POOL
};

static_assert(arraysize(g_max_sockets_per_pool) ==
                  HttpNetworkSession::NUM_SOCKET_POOL_TYPES,
              "max sockets per pool length mismatch");

// Default to allow up to 6 connections per host. Experiment and tuning may
// try other values (greater than 0).  Too large may cause many problems, such
// as home routers blocking the connections!?!?  See http://crbug.com/12066.
//
// WebSocket connections are long-lived, and should be treated differently
// than normal other connections. Use a limit of 255, so the limit for wss will
// be the same as the limit for ws. Also note that Firefox uses a limit of 200.
// See http://crbug.com/486800
int g_max_sockets_per_group[] = {
    6,   // NORMAL_SOCKET_POOL
    255  // WEBSOCKET_SOCKET_POOL
};

static_assert(arraysize(g_max_sockets_per_group) ==
                  HttpNetworkSession::NUM_SOCKET_POOL_TYPES,
              "max sockets per group length mismatch");

// The max number of sockets to allow per proxy server.  This applies both to
// http and SOCKS proxies.  See http://crbug.com/12066 and
// http://crbug.com/44501 for details about proxy server connection limits.
int g_max_sockets_per_proxy_server[] = {
  kDefaultMaxSocketsPerProxyServer,  // NORMAL_SOCKET_POOL
  kDefaultMaxSocketsPerProxyServer   // WEBSOCKET_SOCKET_POOL
};

static_assert(arraysize(g_max_sockets_per_proxy_server) ==
                  HttpNetworkSession::NUM_SOCKET_POOL_TYPES,
              "max sockets per proxy server length mismatch");

// The meat of the implementation for the InitSocketHandleForHttpRequest,
// InitSocketHandleForRawConnect and PreconnectSocketsForHttpRequest methods.
int InitSocketPoolHelper(ClientSocketPoolManager::SocketGroupType group_type,
                         const HostPortPair& endpoint,
                         const HttpRequestHeaders& request_extra_headers,
                         int request_load_flags,
                         RequestPriority request_priority,
                         HttpNetworkSession* session,
                         const ProxyInfo& proxy_info,
                         quic::QuicTransportVersion quic_version,
                         const SSLConfig& ssl_config_for_origin,
                         const SSLConfig& ssl_config_for_proxy,
                         bool force_tunnel,
                         PrivacyMode privacy_mode,
                         const SocketTag& socket_tag,
                         const NetLogWithSource& net_log,
                         int num_preconnect_streams,
                         ClientSocketHandle* socket_handle,
                         HttpNetworkSession::SocketPoolType socket_pool_type,
                         const OnHostResolutionCallback& resolution_callback,
                         CompletionOnceCallback callback) {
  scoped_refptr<HttpProxySocketParams> http_proxy_params;
  scoped_refptr<SOCKSSocketParams> socks_params;
  std::unique_ptr<HostPortPair> proxy_host_port;

  const bool using_ssl = group_type == ClientSocketPoolManager::SSL_GROUP;
  HostPortPair origin_host_port = endpoint;

  if (!using_ssl && session->params().testing_fixed_http_port != 0) {
    origin_host_port.set_port(session->params().testing_fixed_http_port);
  } else if (using_ssl && session->params().testing_fixed_https_port != 0) {
    origin_host_port.set_port(session->params().testing_fixed_https_port);
  }

  // LOAD_BYPASS_CACHE should bypass the host cache as well as the HTTP cache.
  // Other cache-related load flags should not have this effect.
  bool disable_resolver_cache = request_load_flags & LOAD_BYPASS_CACHE;

  // Build the string used to uniquely identify connections of this type.
  // Determine the host and port to connect to.
  std::string connection_group = origin_host_port.ToString();
  DCHECK(!connection_group.empty());
  if (group_type == ClientSocketPoolManager::FTP_GROUP) {
    // Combining FTP with forced SPDY over SSL would be a "path to madness".
    // Make sure we never do that.
    DCHECK(!using_ssl);
    connection_group = "ftp/" + connection_group;
  }
  if (using_ssl) {
    std::string prefix = "ssl/";
    if (ssl_config_for_origin.version_interference_probe) {
      prefix += "version-interference-probe/";
    }
    connection_group = prefix + connection_group;
  }

  ClientSocketPool::RespectLimits respect_limits =
      ClientSocketPool::RespectLimits::ENABLED;
  if ((request_load_flags & LOAD_IGNORE_LIMITS) != 0)
    respect_limits = ClientSocketPool::RespectLimits::DISABLED;

  if (!proxy_info.is_direct()) {
    ProxyServer proxy_server = proxy_info.proxy_server();
    proxy_host_port.reset(new HostPortPair(proxy_server.host_port_pair()));
    scoped_refptr<TransportSocketParams> proxy_tcp_params(
        new TransportSocketParams(*proxy_host_port, disable_resolver_cache,
                                  resolution_callback));

    if (proxy_info.is_http() || proxy_info.is_https() || proxy_info.is_quic()) {
      // TODO(mmenke):  Would it be better to split these into two different
      //     socket pools?  And maybe socks4/socks5 as well?
      if (proxy_info.is_http()) {
        connection_group = "http_proxy/" + connection_group;
      } else {
        connection_group = "https_proxy/" + connection_group;
      }

      std::string user_agent;
      request_extra_headers.GetHeader(HttpRequestHeaders::kUserAgent,
                                      &user_agent);
      scoped_refptr<SSLSocketParams> ssl_params;
      if (!proxy_info.is_http()) {
        proxy_tcp_params = new TransportSocketParams(
            *proxy_host_port, disable_resolver_cache, resolution_callback);
        // Set ssl_params, and unset proxy_tcp_params
        ssl_params =
            new SSLSocketParams(proxy_tcp_params, NULL, NULL, *proxy_host_port,
                                ssl_config_for_proxy, PRIVACY_MODE_DISABLED);
        proxy_tcp_params = NULL;
      }

      if (!proxy_info.is_quic()) {
        quic_version = quic::QUIC_VERSION_UNSUPPORTED;
      }

      http_proxy_params = new HttpProxySocketParams(
          proxy_tcp_params, ssl_params, quic_version, user_agent,
          origin_host_port, session->http_auth_cache(),
          session->http_auth_handler_factory(), session->spdy_session_pool(),
          session->quic_stream_factory(), proxy_server.is_trusted_proxy(),
          force_tunnel || using_ssl,
          NetworkTrafficAnnotationTag(proxy_info.traffic_annotation()));
    } else {
      DCHECK(proxy_info.is_socks());
      char socks_version;
      if (proxy_server.scheme() == ProxyServer::SCHEME_SOCKS5)
        socks_version = '5';
      else
        socks_version = '4';
      connection_group = base::StringPrintf(
          "socks%c/%s", socks_version, connection_group.c_str());

      socks_params = new SOCKSSocketParams(
          proxy_tcp_params, socks_version == '5', origin_host_port,
          NetworkTrafficAnnotationTag(proxy_info.traffic_annotation()));
    }
  }

  // Change group name if privacy mode is enabled.
  if (privacy_mode == PRIVACY_MODE_ENABLED)
    connection_group = "pm/" + connection_group;

  // Deal with SSL - which layers on top of any given proxy.
  if (using_ssl) {
    scoped_refptr<TransportSocketParams> ssl_tcp_params;
    if (proxy_info.is_direct()) {
      ssl_tcp_params = new TransportSocketParams(
          origin_host_port, disable_resolver_cache, resolution_callback);
    }
    scoped_refptr<SSLSocketParams> ssl_params = new SSLSocketParams(
        ssl_tcp_params, socks_params, http_proxy_params, origin_host_port,
        ssl_config_for_origin, privacy_mode);
    SSLClientSocketPool* ssl_pool = NULL;
    if (proxy_info.is_direct()) {
      ssl_pool = session->GetSSLSocketPool(socket_pool_type);
    } else {
      ssl_pool = session->GetSocketPoolForSSLWithProxy(socket_pool_type,
                                                       *proxy_host_port);
    }

    if (num_preconnect_streams) {
      RequestSocketsForPool(ssl_pool, connection_group, ssl_params,
                            num_preconnect_streams, net_log);
      return OK;
    }

    return socket_handle->Init(connection_group, ssl_params, request_priority,
                               socket_tag, respect_limits, std::move(callback),
                               ssl_pool, net_log);
  }

  // Finally, get the connection started.

  if (proxy_info.is_http() || proxy_info.is_https()) {
    HttpProxyClientSocketPool* pool =
        session->GetSocketPoolForHTTPProxy(socket_pool_type, *proxy_host_port);
    if (num_preconnect_streams) {
      RequestSocketsForPool(pool, connection_group, http_proxy_params,
                            num_preconnect_streams, net_log);
      return OK;
    }

    return socket_handle->Init(connection_group, http_proxy_params,
                               request_priority, socket_tag, respect_limits,
                               std::move(callback), pool, net_log);
  }

  if (proxy_info.is_socks()) {
    SOCKSClientSocketPool* pool =
        session->GetSocketPoolForSOCKSProxy(socket_pool_type, *proxy_host_port);
    if (num_preconnect_streams) {
      RequestSocketsForPool(pool, connection_group, socks_params,
                            num_preconnect_streams, net_log);
      return OK;
    }

    return socket_handle->Init(connection_group, socks_params, request_priority,
                               socket_tag, respect_limits, std::move(callback),
                               pool, net_log);
  }

  DCHECK(proxy_info.is_direct());
  scoped_refptr<TransportSocketParams> tcp_params = new TransportSocketParams(
      origin_host_port, disable_resolver_cache, resolution_callback);
  TransportClientSocketPool* pool =
      session->GetTransportSocketPool(socket_pool_type);
  if (num_preconnect_streams) {
    RequestSocketsForPool(pool, connection_group, tcp_params,
                          num_preconnect_streams, net_log);
    return OK;
  }

  return socket_handle->Init(connection_group, tcp_params, request_priority,
                             socket_tag, respect_limits, std::move(callback),
                             pool, net_log);
}

}  // namespace

ClientSocketPoolManager::ClientSocketPoolManager() = default;
ClientSocketPoolManager::~ClientSocketPoolManager() = default;

// static
int ClientSocketPoolManager::max_sockets_per_pool(
    HttpNetworkSession::SocketPoolType pool_type) {
  DCHECK_LT(pool_type, HttpNetworkSession::NUM_SOCKET_POOL_TYPES);
  return g_max_sockets_per_pool[pool_type];
}

// static
void ClientSocketPoolManager::set_max_sockets_per_pool(
    HttpNetworkSession::SocketPoolType pool_type,
    int socket_count) {
  DCHECK_LT(0, socket_count);
  DCHECK_GT(1000, socket_count);  // Sanity check.
  DCHECK_LT(pool_type, HttpNetworkSession::NUM_SOCKET_POOL_TYPES);
  g_max_sockets_per_pool[pool_type] = socket_count;
  DCHECK_GE(g_max_sockets_per_pool[pool_type],
            g_max_sockets_per_group[pool_type]);
}

// static
int ClientSocketPoolManager::max_sockets_per_group(
    HttpNetworkSession::SocketPoolType pool_type) {
  DCHECK_LT(pool_type, HttpNetworkSession::NUM_SOCKET_POOL_TYPES);
  return g_max_sockets_per_group[pool_type];
}

// static
void ClientSocketPoolManager::set_max_sockets_per_group(
    HttpNetworkSession::SocketPoolType pool_type,
    int socket_count) {
  DCHECK_LT(0, socket_count);
  // The following is a sanity check... but we should NEVER be near this value.
  DCHECK_GT(100, socket_count);
  DCHECK_LT(pool_type, HttpNetworkSession::NUM_SOCKET_POOL_TYPES);
  g_max_sockets_per_group[pool_type] = socket_count;

  DCHECK_GE(g_max_sockets_per_pool[pool_type],
            g_max_sockets_per_group[pool_type]);
  DCHECK_GE(g_max_sockets_per_proxy_server[pool_type],
            g_max_sockets_per_group[pool_type]);
}

// static
int ClientSocketPoolManager::max_sockets_per_proxy_server(
    HttpNetworkSession::SocketPoolType pool_type) {
  DCHECK_LT(pool_type, HttpNetworkSession::NUM_SOCKET_POOL_TYPES);
  return g_max_sockets_per_proxy_server[pool_type];
}

// static
void ClientSocketPoolManager::set_max_sockets_per_proxy_server(
    HttpNetworkSession::SocketPoolType pool_type,
    int socket_count) {
  DCHECK_LT(0, socket_count);
  DCHECK_GT(100, socket_count);  // Sanity check.
  DCHECK_LT(pool_type, HttpNetworkSession::NUM_SOCKET_POOL_TYPES);
  // Assert this case early on. The max number of sockets per group cannot
  // exceed the max number of sockets per proxy server.
  DCHECK_LE(g_max_sockets_per_group[pool_type], socket_count);
  g_max_sockets_per_proxy_server[pool_type] = socket_count;
}

int InitSocketHandleForHttpRequest(
    ClientSocketPoolManager::SocketGroupType group_type,
    const HostPortPair& endpoint,
    const HttpRequestHeaders& request_extra_headers,
    int request_load_flags,
    RequestPriority request_priority,
    HttpNetworkSession* session,
    const ProxyInfo& proxy_info,
    quic::QuicTransportVersion quic_version,
    const SSLConfig& ssl_config_for_origin,
    const SSLConfig& ssl_config_for_proxy,
    PrivacyMode privacy_mode,
    const SocketTag& socket_tag,
    const NetLogWithSource& net_log,
    ClientSocketHandle* socket_handle,
    const OnHostResolutionCallback& resolution_callback,
    CompletionOnceCallback callback) {
  DCHECK(socket_handle);
  return InitSocketPoolHelper(
      group_type, endpoint, request_extra_headers, request_load_flags,
      request_priority, session, proxy_info, quic_version,
      ssl_config_for_origin, ssl_config_for_proxy, /*force_tunnel=*/false,
      privacy_mode, socket_tag, net_log, 0, socket_handle,
      HttpNetworkSession::NORMAL_SOCKET_POOL, resolution_callback,
      std::move(callback));
}

int InitSocketHandleForWebSocketRequest(
    ClientSocketPoolManager::SocketGroupType group_type,
    const HostPortPair& endpoint,
    const HttpRequestHeaders& request_extra_headers,
    int request_load_flags,
    RequestPriority request_priority,
    HttpNetworkSession* session,
    const ProxyInfo& proxy_info,
    const SSLConfig& ssl_config_for_origin,
    const SSLConfig& ssl_config_for_proxy,
    PrivacyMode privacy_mode,
    const NetLogWithSource& net_log,
    ClientSocketHandle* socket_handle,
    const OnHostResolutionCallback& resolution_callback,
    CompletionOnceCallback callback) {
  DCHECK(socket_handle);
  return InitSocketPoolHelper(
      group_type, endpoint, request_extra_headers, request_load_flags,
      request_priority, session, proxy_info, quic::QUIC_VERSION_UNSUPPORTED,
      ssl_config_for_origin, ssl_config_for_proxy,
      /*force_tunnel=*/true, privacy_mode, SocketTag(), net_log, 0,
      socket_handle, HttpNetworkSession::WEBSOCKET_SOCKET_POOL,
      resolution_callback, std::move(callback));
}

int InitSocketHandleForRawConnect(const HostPortPair& host_port_pair,
                                  HttpNetworkSession* session,
                                  int request_load_flags,
                                  RequestPriority request_priority,
                                  const ProxyInfo& proxy_info,
                                  const SSLConfig& ssl_config_for_origin,
                                  const SSLConfig& ssl_config_for_proxy,
                                  PrivacyMode privacy_mode,
                                  const NetLogWithSource& net_log,
                                  ClientSocketHandle* socket_handle,
                                  CompletionOnceCallback callback) {
  DCHECK(socket_handle);
  HttpRequestHeaders request_extra_headers;
  return InitSocketPoolHelper(
      ClientSocketPoolManager::NORMAL_GROUP, host_port_pair,
      request_extra_headers, request_load_flags, request_priority, session,
      proxy_info, quic::QUIC_VERSION_UNSUPPORTED, ssl_config_for_origin,
      ssl_config_for_proxy, /*force_tunnel=*/true, privacy_mode, SocketTag(),
      net_log, 0, socket_handle, HttpNetworkSession::NORMAL_SOCKET_POOL,
      OnHostResolutionCallback(), std::move(callback));
}

int InitSocketHandleForTlsConnect(const HostPortPair& endpoint,
                                  HttpNetworkSession* session,
                                  int request_load_flags,
                                  RequestPriority request_priority,
                                  const ProxyInfo& proxy_info,
                                  const SSLConfig& ssl_config_for_origin,
                                  const SSLConfig& ssl_config_for_proxy,
                                  PrivacyMode privacy_mode,
                                  const NetLogWithSource& net_log,
                                  ClientSocketHandle* socket_handle,
                                  CompletionOnceCallback callback) {
  DCHECK(socket_handle);
  HttpRequestHeaders request_extra_headers;
  return InitSocketPoolHelper(
      ClientSocketPoolManager::SSL_GROUP, endpoint, request_extra_headers,
      request_load_flags, request_priority, session, proxy_info,
      quic::QUIC_VERSION_UNSUPPORTED, ssl_config_for_origin,
      ssl_config_for_proxy,
      /*force_tunnel=*/true, privacy_mode, SocketTag(), net_log, 0,
      socket_handle, HttpNetworkSession::NORMAL_SOCKET_POOL,
      OnHostResolutionCallback(), std::move(callback));
}

int PreconnectSocketsForHttpRequest(
    ClientSocketPoolManager::SocketGroupType group_type,
    const HostPortPair& endpoint,
    const HttpRequestHeaders& request_extra_headers,
    int request_load_flags,
    RequestPriority request_priority,
    HttpNetworkSession* session,
    const ProxyInfo& proxy_info,
    const SSLConfig& ssl_config_for_origin,
    const SSLConfig& ssl_config_for_proxy,
    PrivacyMode privacy_mode,
    const NetLogWithSource& net_log,
    int num_preconnect_streams) {
  return InitSocketPoolHelper(
      group_type, endpoint, request_extra_headers, request_load_flags,
      request_priority, session, proxy_info, quic::QUIC_VERSION_UNSUPPORTED,
      ssl_config_for_origin, ssl_config_for_proxy,
      /*force_tunnel=*/false, privacy_mode, SocketTag(), net_log,
      num_preconnect_streams, NULL, HttpNetworkSession::NORMAL_SOCKET_POOL,
      OnHostResolutionCallback(), CompletionOnceCallback());
}

}  // namespace net