| /* |
| * Copyright 2004 The WebRTC Project Authors. All rights reserved. |
| * |
| * Use of this source code is governed by a BSD-style license |
| * that can be found in the LICENSE file in the root of the source |
| * tree. An additional intellectual property rights grant can be found |
| * in the file PATENTS. All contributing project authors may |
| * be found in the AUTHORS file in the root of the source tree. |
| */ |
| |
| #include <memory> |
| |
| #include "webrtc/base/natsocketfactory.h" |
| #include "webrtc/base/natserver.h" |
| #include "webrtc/base/logging.h" |
| #include "webrtc/base/socketadapters.h" |
| |
| namespace rtc { |
| |
| RouteCmp::RouteCmp(NAT* nat) : symmetric(nat->IsSymmetric()) { |
| } |
| |
| size_t RouteCmp::operator()(const SocketAddressPair& r) const { |
| size_t h = r.source().Hash(); |
| if (symmetric) |
| h ^= r.destination().Hash(); |
| return h; |
| } |
| |
| bool RouteCmp::operator()( |
| const SocketAddressPair& r1, const SocketAddressPair& r2) const { |
| if (r1.source() < r2.source()) |
| return true; |
| if (r2.source() < r1.source()) |
| return false; |
| if (symmetric && (r1.destination() < r2.destination())) |
| return true; |
| if (symmetric && (r2.destination() < r1.destination())) |
| return false; |
| return false; |
| } |
| |
| AddrCmp::AddrCmp(NAT* nat) |
| : use_ip(nat->FiltersIP()), use_port(nat->FiltersPort()) { |
| } |
| |
| size_t AddrCmp::operator()(const SocketAddress& a) const { |
| size_t h = 0; |
| if (use_ip) |
| h ^= HashIP(a.ipaddr()); |
| if (use_port) |
| h ^= a.port() | (a.port() << 16); |
| return h; |
| } |
| |
| bool AddrCmp::operator()( |
| const SocketAddress& a1, const SocketAddress& a2) const { |
| if (use_ip && (a1.ipaddr() < a2.ipaddr())) |
| return true; |
| if (use_ip && (a2.ipaddr() < a1.ipaddr())) |
| return false; |
| if (use_port && (a1.port() < a2.port())) |
| return true; |
| if (use_port && (a2.port() < a1.port())) |
| return false; |
| return false; |
| } |
| |
| // Proxy socket that will capture the external destination address intended for |
| // a TCP connection to the NAT server. |
| class NATProxyServerSocket : public AsyncProxyServerSocket { |
| public: |
| NATProxyServerSocket(AsyncSocket* socket) |
| : AsyncProxyServerSocket(socket, kNATEncodedIPv6AddressSize) { |
| BufferInput(true); |
| } |
| |
| void SendConnectResult(int err, const SocketAddress& addr) override { |
| char code = err ? 1 : 0; |
| BufferedReadAdapter::DirectSend(&code, sizeof(char)); |
| } |
| |
| protected: |
| void ProcessInput(char* data, size_t* len) override { |
| if (*len < 2) { |
| return; |
| } |
| |
| int family = data[1]; |
| ASSERT(family == AF_INET || family == AF_INET6); |
| if ((family == AF_INET && *len < kNATEncodedIPv4AddressSize) || |
| (family == AF_INET6 && *len < kNATEncodedIPv6AddressSize)) { |
| return; |
| } |
| |
| SocketAddress dest_addr; |
| size_t address_length = UnpackAddressFromNAT(data, *len, &dest_addr); |
| |
| *len -= address_length; |
| if (*len > 0) { |
| memmove(data, data + address_length, *len); |
| } |
| |
| bool remainder = (*len > 0); |
| BufferInput(false); |
| SignalConnectRequest(this, dest_addr); |
| if (remainder) { |
| SignalReadEvent(this); |
| } |
| } |
| |
| }; |
| |
| class NATProxyServer : public ProxyServer { |
| public: |
| NATProxyServer(SocketFactory* int_factory, const SocketAddress& int_addr, |
| SocketFactory* ext_factory, const SocketAddress& ext_ip) |
| : ProxyServer(int_factory, int_addr, ext_factory, ext_ip) { |
| } |
| |
| protected: |
| AsyncProxyServerSocket* WrapSocket(AsyncSocket* socket) override { |
| return new NATProxyServerSocket(socket); |
| } |
| }; |
| |
| NATServer::NATServer( |
| NATType type, SocketFactory* internal, |
| const SocketAddress& internal_udp_addr, |
| const SocketAddress& internal_tcp_addr, |
| SocketFactory* external, const SocketAddress& external_ip) |
| : external_(external), external_ip_(external_ip.ipaddr(), 0) { |
| nat_ = NAT::Create(type); |
| |
| udp_server_socket_ = AsyncUDPSocket::Create(internal, internal_udp_addr); |
| udp_server_socket_->SignalReadPacket.connect(this, |
| &NATServer::OnInternalUDPPacket); |
| tcp_proxy_server_ = new NATProxyServer(internal, internal_tcp_addr, external, |
| external_ip); |
| |
| int_map_ = new InternalMap(RouteCmp(nat_)); |
| ext_map_ = new ExternalMap(); |
| } |
| |
| NATServer::~NATServer() { |
| for (InternalMap::iterator iter = int_map_->begin(); |
| iter != int_map_->end(); |
| iter++) |
| delete iter->second; |
| |
| delete nat_; |
| delete udp_server_socket_; |
| delete tcp_proxy_server_; |
| delete int_map_; |
| delete ext_map_; |
| } |
| |
| void NATServer::OnInternalUDPPacket( |
| AsyncPacketSocket* socket, const char* buf, size_t size, |
| const SocketAddress& addr, const PacketTime& packet_time) { |
| // Read the intended destination from the wire. |
| SocketAddress dest_addr; |
| size_t length = UnpackAddressFromNAT(buf, size, &dest_addr); |
| |
| // Find the translation for these addresses (allocating one if necessary). |
| SocketAddressPair route(addr, dest_addr); |
| InternalMap::iterator iter = int_map_->find(route); |
| if (iter == int_map_->end()) { |
| Translate(route); |
| iter = int_map_->find(route); |
| } |
| ASSERT(iter != int_map_->end()); |
| |
| // Allow the destination to send packets back to the source. |
| iter->second->WhitelistInsert(dest_addr); |
| |
| // Send the packet to its intended destination. |
| rtc::PacketOptions options; |
| iter->second->socket->SendTo(buf + length, size - length, dest_addr, options); |
| } |
| |
| void NATServer::OnExternalUDPPacket( |
| AsyncPacketSocket* socket, const char* buf, size_t size, |
| const SocketAddress& remote_addr, const PacketTime& packet_time) { |
| SocketAddress local_addr = socket->GetLocalAddress(); |
| |
| // Find the translation for this addresses. |
| ExternalMap::iterator iter = ext_map_->find(local_addr); |
| ASSERT(iter != ext_map_->end()); |
| |
| // Allow the NAT to reject this packet. |
| if (ShouldFilterOut(iter->second, remote_addr)) { |
| LOG(LS_INFO) << "Packet from " << remote_addr.ToSensitiveString() |
| << " was filtered out by the NAT."; |
| return; |
| } |
| |
| // Forward this packet to the internal address. |
| // First prepend the address in a quasi-STUN format. |
| std::unique_ptr<char[]> real_buf(new char[size + kNATEncodedIPv6AddressSize]); |
| size_t addrlength = PackAddressForNAT(real_buf.get(), |
| size + kNATEncodedIPv6AddressSize, |
| remote_addr); |
| // Copy the data part after the address. |
| rtc::PacketOptions options; |
| memcpy(real_buf.get() + addrlength, buf, size); |
| udp_server_socket_->SendTo(real_buf.get(), size + addrlength, |
| iter->second->route.source(), options); |
| } |
| |
| void NATServer::Translate(const SocketAddressPair& route) { |
| AsyncUDPSocket* socket = AsyncUDPSocket::Create(external_, external_ip_); |
| |
| if (!socket) { |
| LOG(LS_ERROR) << "Couldn't find a free port!"; |
| return; |
| } |
| |
| TransEntry* entry = new TransEntry(route, socket, nat_); |
| (*int_map_)[route] = entry; |
| (*ext_map_)[socket->GetLocalAddress()] = entry; |
| socket->SignalReadPacket.connect(this, &NATServer::OnExternalUDPPacket); |
| } |
| |
| bool NATServer::ShouldFilterOut(TransEntry* entry, |
| const SocketAddress& ext_addr) { |
| return entry->WhitelistContains(ext_addr); |
| } |
| |
| NATServer::TransEntry::TransEntry( |
| const SocketAddressPair& r, AsyncUDPSocket* s, NAT* nat) |
| : route(r), socket(s) { |
| whitelist = new AddressSet(AddrCmp(nat)); |
| } |
| |
| NATServer::TransEntry::~TransEntry() { |
| delete whitelist; |
| delete socket; |
| } |
| |
| void NATServer::TransEntry::WhitelistInsert(const SocketAddress& addr) { |
| CritScope cs(&crit_); |
| whitelist->insert(addr); |
| } |
| |
| bool NATServer::TransEntry::WhitelistContains(const SocketAddress& ext_addr) { |
| CritScope cs(&crit_); |
| return whitelist->find(ext_addr) == whitelist->end(); |
| } |
| |
| } // namespace rtc |