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 RTC_BASE_NATSERVER_H_ 12 #define RTC_BASE_NATSERVER_H_ 13 14 #include <map> 15 #include <set> 16 17 #include "rtc_base/asyncudpsocket.h" 18 #include "rtc_base/constructormagic.h" 19 #include "rtc_base/nattypes.h" 20 #include "rtc_base/proxyserver.h" 21 #include "rtc_base/socketaddresspair.h" 22 #include "rtc_base/socketfactory.h" 23 #include "rtc_base/thread.h" 24 25 namespace rtc { 26 27 // Change how routes (socketaddress pairs) are compared based on the type of 28 // NAT. The NAT server maintains a hashtable of the routes that it knows 29 // about. So these affect which routes are treated the same. 30 struct RouteCmp { 31 explicit RouteCmp(NAT* nat); 32 size_t operator()(const SocketAddressPair& r) const; 33 bool operator()( 34 const SocketAddressPair& r1, const SocketAddressPair& r2) const; 35 36 bool symmetric; 37 }; 38 39 // Changes how addresses are compared based on the filtering rules of the NAT. 40 struct AddrCmp { 41 explicit AddrCmp(NAT* nat); 42 size_t operator()(const SocketAddress& r) const; 43 bool operator()(const SocketAddress& r1, const SocketAddress& r2) const; 44 45 bool use_ip; 46 bool use_port; 47 }; 48 49 // Implements the NAT device. It listens for packets on the internal network, 50 // translates them, and sends them out over the external network. 51 // 52 // TCP connections initiated from the internal side of the NAT server are 53 // also supported, by making a connection to the NAT server's TCP address and 54 // then sending the remote address in quasi-STUN format. The connection status 55 // will be indicated back to the client as a 1 byte status code, where '0' 56 // indicates success. 57 58 const int NAT_SERVER_UDP_PORT = 4237; 59 const int NAT_SERVER_TCP_PORT = 4238; 60 61 class NATServer : public sigslot::has_slots<> { 62 public: 63 NATServer( 64 NATType type, SocketFactory* internal, 65 const SocketAddress& internal_udp_addr, 66 const SocketAddress& internal_tcp_addr, 67 SocketFactory* external, const SocketAddress& external_ip); 68 ~NATServer() override; 69 internal_udp_address()70 SocketAddress internal_udp_address() const { 71 return udp_server_socket_->GetLocalAddress(); 72 } 73 internal_tcp_address()74 SocketAddress internal_tcp_address() const { 75 return tcp_proxy_server_->GetServerAddress(); 76 } 77 78 // Packets received on one of the networks. 79 void OnInternalUDPPacket(AsyncPacketSocket* socket, const char* buf, 80 size_t size, const SocketAddress& addr, 81 const PacketTime& packet_time); 82 void OnExternalUDPPacket(AsyncPacketSocket* socket, const char* buf, 83 size_t size, const SocketAddress& remote_addr, 84 const PacketTime& packet_time); 85 86 private: 87 typedef std::set<SocketAddress, AddrCmp> AddressSet; 88 89 /* Records a translation and the associated external socket. */ 90 struct TransEntry { 91 TransEntry(const SocketAddressPair& r, AsyncUDPSocket* s, NAT* nat); 92 ~TransEntry(); 93 94 void WhitelistInsert(const SocketAddress& addr); 95 bool WhitelistContains(const SocketAddress& ext_addr); 96 97 SocketAddressPair route; 98 AsyncUDPSocket* socket; 99 AddressSet* whitelist; 100 CriticalSection crit_; 101 }; 102 103 typedef std::map<SocketAddressPair, TransEntry*, RouteCmp> InternalMap; 104 typedef std::map<SocketAddress, TransEntry*> ExternalMap; 105 106 /* Creates a new entry that translates the given route. */ 107 void Translate(const SocketAddressPair& route); 108 109 /* Determines whether the NAT would filter out a packet from this address. */ 110 bool ShouldFilterOut(TransEntry* entry, const SocketAddress& ext_addr); 111 112 NAT* nat_; 113 SocketFactory* external_; 114 SocketAddress external_ip_; 115 AsyncUDPSocket* udp_server_socket_; 116 ProxyServer* tcp_proxy_server_; 117 InternalMap* int_map_; 118 ExternalMap* ext_map_; 119 RTC_DISALLOW_COPY_AND_ASSIGN(NATServer); 120 }; 121 122 } // namespace rtc 123 124 #endif // RTC_BASE_NATSERVER_H_ 125