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 #ifndef WEBRTC_BASE_NATSERVER_H_ 12 #define WEBRTC_BASE_NATSERVER_H_ 13 14 #include <map> 15 #include <set> 16 17 #include "webrtc/base/asyncudpsocket.h" 18 #include "webrtc/base/socketaddresspair.h" 19 #include "webrtc/base/thread.h" 20 #include "webrtc/base/socketfactory.h" 21 #include "webrtc/base/nattypes.h" 22 #include "webrtc/base/proxyserver.h" 23 24 namespace rtc { 25 26 // Change how routes (socketaddress pairs) are compared based on the type of 27 // NAT. The NAT server maintains a hashtable of the routes that it knows 28 // about. So these affect which routes are treated the same. 29 struct RouteCmp { 30 explicit RouteCmp(NAT* nat); 31 size_t operator()(const SocketAddressPair& r) const; 32 bool operator()( 33 const SocketAddressPair& r1, const SocketAddressPair& r2) const; 34 35 bool symmetric; 36 }; 37 38 // Changes how addresses are compared based on the filtering rules of the NAT. 39 struct AddrCmp { 40 explicit AddrCmp(NAT* nat); 41 size_t operator()(const SocketAddress& r) const; 42 bool operator()(const SocketAddress& r1, const SocketAddress& r2) const; 43 44 bool use_ip; 45 bool use_port; 46 }; 47 48 // Implements the NAT device. It listens for packets on the internal network, 49 // translates them, and sends them out over the external network. 50 // 51 // TCP connections initiated from the internal side of the NAT server are 52 // also supported, by making a connection to the NAT server's TCP address and 53 // then sending the remote address in quasi-STUN format. The connection status 54 // will be indicated back to the client as a 1 byte status code, where '0' 55 // indicates success. 56 57 const int NAT_SERVER_UDP_PORT = 4237; 58 const int NAT_SERVER_TCP_PORT = 4238; 59 60 class NATServer : public sigslot::has_slots<> { 61 public: 62 NATServer( 63 NATType type, SocketFactory* internal, 64 const SocketAddress& internal_udp_addr, 65 const SocketAddress& internal_tcp_addr, 66 SocketFactory* external, const SocketAddress& external_ip); 67 ~NATServer() override; 68 internal_udp_address()69 SocketAddress internal_udp_address() const { 70 return udp_server_socket_->GetLocalAddress(); 71 } 72 internal_tcp_address()73 SocketAddress internal_tcp_address() const { 74 return tcp_proxy_server_->GetServerAddress(); 75 } 76 77 // Packets received on one of the networks. 78 void OnInternalUDPPacket(AsyncPacketSocket* socket, const char* buf, 79 size_t size, const SocketAddress& addr, 80 const PacketTime& packet_time); 81 void OnExternalUDPPacket(AsyncPacketSocket* socket, const char* buf, 82 size_t size, const SocketAddress& remote_addr, 83 const PacketTime& packet_time); 84 85 private: 86 typedef std::set<SocketAddress, AddrCmp> AddressSet; 87 88 /* Records a translation and the associated external socket. */ 89 struct TransEntry { 90 TransEntry(const SocketAddressPair& r, AsyncUDPSocket* s, NAT* nat); 91 ~TransEntry(); 92 93 void WhitelistInsert(const SocketAddress& addr); 94 bool WhitelistContains(const SocketAddress& ext_addr); 95 96 SocketAddressPair route; 97 AsyncUDPSocket* socket; 98 AddressSet* whitelist; 99 CriticalSection crit_; 100 }; 101 102 typedef std::map<SocketAddressPair, TransEntry*, RouteCmp> InternalMap; 103 typedef std::map<SocketAddress, TransEntry*> ExternalMap; 104 105 /* Creates a new entry that translates the given route. */ 106 void Translate(const SocketAddressPair& route); 107 108 /* Determines whether the NAT would filter out a packet from this address. */ 109 bool ShouldFilterOut(TransEntry* entry, const SocketAddress& ext_addr); 110 111 NAT* nat_; 112 SocketFactory* external_; 113 SocketAddress external_ip_; 114 AsyncUDPSocket* udp_server_socket_; 115 ProxyServer* tcp_proxy_server_; 116 InternalMap* int_map_; 117 ExternalMap* ext_map_; 118 RTC_DISALLOW_COPY_AND_ASSIGN(NATServer); 119 }; 120 121 } // namespace rtc 122 123 #endif // WEBRTC_BASE_NATSERVER_H_ 124