1 /* 2 * Copyright 2004 The WebRTC Project Authors. All rights reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #include "webrtc/base/natsocketfactory.h" 12 #include "webrtc/base/natserver.h" 13 #include "webrtc/base/logging.h" 14 15 namespace rtc { 16 17 RouteCmp::RouteCmp(NAT* nat) : symmetric(nat->IsSymmetric()) { 18 } 19 20 size_t RouteCmp::operator()(const SocketAddressPair& r) const { 21 size_t h = r.source().Hash(); 22 if (symmetric) 23 h ^= r.destination().Hash(); 24 return h; 25 } 26 27 bool RouteCmp::operator()( 28 const SocketAddressPair& r1, const SocketAddressPair& r2) const { 29 if (r1.source() < r2.source()) 30 return true; 31 if (r2.source() < r1.source()) 32 return false; 33 if (symmetric && (r1.destination() < r2.destination())) 34 return true; 35 if (symmetric && (r2.destination() < r1.destination())) 36 return false; 37 return false; 38 } 39 40 AddrCmp::AddrCmp(NAT* nat) 41 : use_ip(nat->FiltersIP()), use_port(nat->FiltersPort()) { 42 } 43 44 size_t AddrCmp::operator()(const SocketAddress& a) const { 45 size_t h = 0; 46 if (use_ip) 47 h ^= HashIP(a.ipaddr()); 48 if (use_port) 49 h ^= a.port() | (a.port() << 16); 50 return h; 51 } 52 53 bool AddrCmp::operator()( 54 const SocketAddress& a1, const SocketAddress& a2) const { 55 if (use_ip && (a1.ipaddr() < a2.ipaddr())) 56 return true; 57 if (use_ip && (a2.ipaddr() < a1.ipaddr())) 58 return false; 59 if (use_port && (a1.port() < a2.port())) 60 return true; 61 if (use_port && (a2.port() < a1.port())) 62 return false; 63 return false; 64 } 65 66 NATServer::NATServer( 67 NATType type, SocketFactory* internal, const SocketAddress& internal_addr, 68 SocketFactory* external, const SocketAddress& external_ip) 69 : external_(external), external_ip_(external_ip.ipaddr(), 0) { 70 nat_ = NAT::Create(type); 71 72 server_socket_ = AsyncUDPSocket::Create(internal, internal_addr); 73 server_socket_->SignalReadPacket.connect(this, &NATServer::OnInternalPacket); 74 75 int_map_ = new InternalMap(RouteCmp(nat_)); 76 ext_map_ = new ExternalMap(); 77 } 78 79 NATServer::~NATServer() { 80 for (InternalMap::iterator iter = int_map_->begin(); 81 iter != int_map_->end(); 82 iter++) 83 delete iter->second; 84 85 delete nat_; 86 delete server_socket_; 87 delete int_map_; 88 delete ext_map_; 89 } 90 91 void NATServer::OnInternalPacket( 92 AsyncPacketSocket* socket, const char* buf, size_t size, 93 const SocketAddress& addr, const PacketTime& packet_time) { 94 95 // Read the intended destination from the wire. 96 SocketAddress dest_addr; 97 size_t length = UnpackAddressFromNAT(buf, size, &dest_addr); 98 99 // Find the translation for these addresses (allocating one if necessary). 100 SocketAddressPair route(addr, dest_addr); 101 InternalMap::iterator iter = int_map_->find(route); 102 if (iter == int_map_->end()) { 103 Translate(route); 104 iter = int_map_->find(route); 105 } 106 ASSERT(iter != int_map_->end()); 107 108 // Allow the destination to send packets back to the source. 109 iter->second->WhitelistInsert(dest_addr); 110 111 // Send the packet to its intended destination. 112 rtc::PacketOptions options; 113 iter->second->socket->SendTo(buf + length, size - length, dest_addr, options); 114 } 115 116 void NATServer::OnExternalPacket( 117 AsyncPacketSocket* socket, const char* buf, size_t size, 118 const SocketAddress& remote_addr, const PacketTime& packet_time) { 119 120 SocketAddress local_addr = socket->GetLocalAddress(); 121 122 // Find the translation for this addresses. 123 ExternalMap::iterator iter = ext_map_->find(local_addr); 124 ASSERT(iter != ext_map_->end()); 125 126 // Allow the NAT to reject this packet. 127 if (ShouldFilterOut(iter->second, remote_addr)) { 128 LOG(LS_INFO) << "Packet from " << remote_addr.ToSensitiveString() 129 << " was filtered out by the NAT."; 130 return; 131 } 132 133 // Forward this packet to the internal address. 134 // First prepend the address in a quasi-STUN format. 135 scoped_ptr<char[]> real_buf(new char[size + kNATEncodedIPv6AddressSize]); 136 size_t addrlength = PackAddressForNAT(real_buf.get(), 137 size + kNATEncodedIPv6AddressSize, 138 remote_addr); 139 // Copy the data part after the address. 140 rtc::PacketOptions options; 141 memcpy(real_buf.get() + addrlength, buf, size); 142 server_socket_->SendTo(real_buf.get(), size + addrlength, 143 iter->second->route.source(), options); 144 } 145 146 void NATServer::Translate(const SocketAddressPair& route) { 147 AsyncUDPSocket* socket = AsyncUDPSocket::Create(external_, external_ip_); 148 149 if (!socket) { 150 LOG(LS_ERROR) << "Couldn't find a free port!"; 151 return; 152 } 153 154 TransEntry* entry = new TransEntry(route, socket, nat_); 155 (*int_map_)[route] = entry; 156 (*ext_map_)[socket->GetLocalAddress()] = entry; 157 socket->SignalReadPacket.connect(this, &NATServer::OnExternalPacket); 158 } 159 160 bool NATServer::ShouldFilterOut(TransEntry* entry, 161 const SocketAddress& ext_addr) { 162 return entry->WhitelistContains(ext_addr); 163 } 164 165 NATServer::TransEntry::TransEntry( 166 const SocketAddressPair& r, AsyncUDPSocket* s, NAT* nat) 167 : route(r), socket(s) { 168 whitelist = new AddressSet(AddrCmp(nat)); 169 } 170 171 NATServer::TransEntry::~TransEntry() { 172 delete whitelist; 173 delete socket; 174 } 175 176 void NATServer::TransEntry::WhitelistInsert(const SocketAddress& addr) { 177 CritScope cs(&crit_); 178 whitelist->insert(addr); 179 } 180 181 bool NATServer::TransEntry::WhitelistContains(const SocketAddress& ext_addr) { 182 CritScope cs(&crit_); 183 return whitelist->find(ext_addr) == whitelist->end(); 184 } 185 186 } // namespace rtc 187
