net/dns/dns_socket_pool.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "net/dns/dns_socket_pool.h"
   6
   7 #include "base/logging.h"
   8 #include "base/rand_util.h"
   9 #include "base/stl_util.h"
  10 #include "net/base/address_list.h"
  11 #include "net/base/ip_endpoint.h"
  12 #include "net/base/net_errors.h"
  13 #include "net/base/rand_callback.h"
  14 #include "net/socket/client_socket_factory.h"
  15 #include "net/socket/stream_socket.h"
  16 #include "net/udp/datagram_client_socket.h"
  17
  18 namespace net {
  19
  20 namespace {
  21
  22 // When we initialize the SocketPool, we allocate kInitialPoolSize sockets.
  23 // When we allocate a socket, we ensure we have at least kAllocateMinSize
  24 // sockets to choose from.  Freed sockets are not retained.
  25
  26 // On Windows, we can't request specific (random) ports, since that will
  27 // trigger firewall prompts, so request default ones, but keep a pile of
  28 // them.  Everywhere else, request fresh, random ports each time.
  29 #if defined(OS_WIN)
  30 const DatagramSocket::BindType kBindType = DatagramSocket::DEFAULT_BIND;
  31 const unsigned kInitialPoolSize = 256;
  32 const unsigned kAllocateMinSize = 256;
  33 #else
  34 const DatagramSocket::BindType kBindType = DatagramSocket::RANDOM_BIND;
  35 const unsigned kInitialPoolSize = 0;
  36 const unsigned kAllocateMinSize = 1;
  37 #endif
  38
  39 } // namespace
  40
  41 DnsSocketPool::DnsSocketPool(ClientSocketFactory* socket_factory)
  42     : socket_factory_(socket_factory),
  43       net_log_(NULL),
  44       nameservers_(NULL),
  45       initialized_(false) {
  46 }
  47
  48 void DnsSocketPool::InitializeInternal(
  49     const std::vector<IPEndPoint>* nameservers,
  50     NetLog* net_log) {
  51   DCHECK(nameservers);
  52   DCHECK(!initialized_);
  53
  54   net_log_ = net_log;
  55   nameservers_ = nameservers;
  56   initialized_ = true;
  57 }
  58
  59 scoped_ptr<StreamSocket> DnsSocketPool::CreateTCPSocket(
  60     unsigned server_index,
  61     const NetLog::Source& source) {
  62   DCHECK_LT(server_index, nameservers_->size());
  63
  64   return scoped_ptr<StreamSocket>(
  65       socket_factory_->CreateTransportClientSocket(
  66           AddressList((*nameservers_)[server_index]), net_log_, source));
  67 }
  68
  69 scoped_ptr<DatagramClientSocket> DnsSocketPool::CreateConnectedSocket(
  70     unsigned server_index) {
  71   DCHECK_LT(server_index, nameservers_->size());
  72
  73   scoped_ptr<DatagramClientSocket> socket;
  74
  75   NetLog::Source no_source;
  76   socket = socket_factory_->CreateDatagramClientSocket(
  77       kBindType, base::Bind(&base::RandInt), net_log_, no_source);
  78
  79   if (socket.get()) {
  80     int rv = socket->Connect((*nameservers_)[server_index]);
  81     if (rv != OK) {
  82       VLOG(1) << "Failed to connect socket: " << rv;
  83       socket.reset();
  84     }
  85   } else {
  86     LOG(WARNING) << "Failed to create socket.";
  87   }
  88
  89   return socket.Pass();
  90 }
  91
  92 class NullDnsSocketPool : public DnsSocketPool {
  93  public:
  94   NullDnsSocketPool(ClientSocketFactory* factory)
  95      : DnsSocketPool(factory) {
  96   }
  97
  98   void Initialize(const std::vector<IPEndPoint>* nameservers,
  99                   NetLog* net_log) override {
 100     InitializeInternal(nameservers, net_log);
 101   }
 102
 103   scoped_ptr<DatagramClientSocket> AllocateSocket(
 104       unsigned server_index) override {
 105     return CreateConnectedSocket(server_index);
 106   }
 107
 108   void FreeSocket(unsigned server_index,
 109                   scoped_ptr<DatagramClientSocket> socket) override {}
 110
 111  private:
 112   DISALLOW_COPY_AND_ASSIGN(NullDnsSocketPool);
 113 };
 114
 115 // static
 116 scoped_ptr<DnsSocketPool> DnsSocketPool::CreateNull(
 117     ClientSocketFactory* factory) {
 118   return scoped_ptr<DnsSocketPool>(new NullDnsSocketPool(factory));
 119 }
 120
 121 class DefaultDnsSocketPool : public DnsSocketPool {
 122  public:
 123   DefaultDnsSocketPool(ClientSocketFactory* factory)
 124      : DnsSocketPool(factory) {
 125   };
 126
 127   ~DefaultDnsSocketPool() override;
 128
 129   void Initialize(const std::vector<IPEndPoint>* nameservers,
 130                   NetLog* net_log) override;
 131
 132   scoped_ptr<DatagramClientSocket> AllocateSocket(
 133       unsigned server_index) override;
 134
 135   void FreeSocket(unsigned server_index,
 136                   scoped_ptr<DatagramClientSocket> socket) override;
 137
 138  private:
 139   void FillPool(unsigned server_index, unsigned size);
 140
 141   typedef std::vector<DatagramClientSocket*> SocketVector;
 142
 143   std::vector<SocketVector> pools_;
 144
 145   DISALLOW_COPY_AND_ASSIGN(DefaultDnsSocketPool);
 146 };
 147
 148 // static
 149 scoped_ptr<DnsSocketPool> DnsSocketPool::CreateDefault(
 150     ClientSocketFactory* factory) {
 151   return scoped_ptr<DnsSocketPool>(new DefaultDnsSocketPool(factory));
 152 }
 153
 154 void DefaultDnsSocketPool::Initialize(
 155     const std::vector<IPEndPoint>* nameservers,
 156     NetLog* net_log) {
 157   InitializeInternal(nameservers, net_log);
 158
 159   DCHECK(pools_.empty());
 160   const unsigned num_servers = nameservers->size();
 161   pools_.resize(num_servers);
 162   for (unsigned server_index = 0; server_index < num_servers; ++server_index)
 163     FillPool(server_index, kInitialPoolSize);
 164 }
 165
 166 DefaultDnsSocketPool::~DefaultDnsSocketPool() {
 167   unsigned num_servers = pools_.size();
 168   for (unsigned server_index = 0; server_index < num_servers; ++server_index) {
 169     SocketVector& pool = pools_[server_index];
 170     STLDeleteElements(&pool);
 171   }
 172 }
 173
 174 scoped_ptr<DatagramClientSocket> DefaultDnsSocketPool::AllocateSocket(
 175     unsigned server_index) {
 176   DCHECK_LT(server_index, pools_.size());
 177   SocketVector& pool = pools_[server_index];
 178
 179   FillPool(server_index, kAllocateMinSize);
 180   if (pool.size() == 0) {
 181     LOG(WARNING) << "No DNS sockets available in pool " << server_index << "!";
 182     return scoped_ptr<DatagramClientSocket>();
 183   }
 184
 185   if (pool.size() < kAllocateMinSize) {
 186     LOG(WARNING) << "Low DNS port entropy: wanted " << kAllocateMinSize
 187                  << " sockets to choose from, but only have " << pool.size()
 188                  << " in pool " << server_index << ".";
 189   }
 190
 191   unsigned socket_index = base::RandInt(0, pool.size() - 1);
 192   DatagramClientSocket* socket = pool[socket_index];
 193   pool[socket_index] = pool.back();
 194   pool.pop_back();
 195
 196   return scoped_ptr<DatagramClientSocket>(socket);
 197 }
 198
 199 void DefaultDnsSocketPool::FreeSocket(
 200     unsigned server_index,
 201     scoped_ptr<DatagramClientSocket> socket) {
 202   DCHECK_LT(server_index, pools_.size());
 203 }
 204
 205 void DefaultDnsSocketPool::FillPool(unsigned server_index, unsigned size) {
 206   SocketVector& pool = pools_[server_index];
 207
 208   for (unsigned pool_index = pool.size(); pool_index < size; ++pool_index) {
 209     DatagramClientSocket* socket =
 210         CreateConnectedSocket(server_index).release();
 211     if (!socket)
 212       break;
 213     pool.push_back(socket);
 214   }
 215 }
 216
 217 } // namespace net