1/*
2 * libjingle
3 * Copyright 2004--2005, Google Inc.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 *  1. Redistributions of source code must retain the above copyright notice,
9 *     this list of conditions and the following disclaimer.
10 *  2. Redistributions in binary form must reproduce the above copyright notice,
11 *     this list of conditions and the following disclaimer in the documentation
12 *     and/or other materials provided with the distribution.
13 *  3. The name of the author may not be used to endorse or promote products
14 *     derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#ifndef TALK_BASE_NATSERVER_H_
29#define TALK_BASE_NATSERVER_H_
30
31#include <map>
32#include <set>
33
34#include "talk/base/asyncudpsocket.h"
35#include "talk/base/socketaddresspair.h"
36#include "talk/base/thread.h"
37#include "talk/base/socketfactory.h"
38#include "talk/base/nattypes.h"
39
40namespace talk_base {
41
42// Change how routes (socketaddress pairs) are compared based on the type of
43// NAT.  The NAT server maintains a hashtable of the routes that it knows
44// about.  So these affect which routes are treated the same.
45struct RouteCmp {
46  explicit RouteCmp(NAT* nat);
47  size_t operator()(const SocketAddressPair& r) const;
48  bool operator()(
49      const SocketAddressPair& r1, const SocketAddressPair& r2) const;
50
51  bool symmetric;
52};
53
54// Changes how addresses are compared based on the filtering rules of the NAT.
55struct AddrCmp {
56  explicit AddrCmp(NAT* nat);
57  size_t operator()(const SocketAddress& r) const;
58  bool operator()(const SocketAddress& r1, const SocketAddress& r2) const;
59
60  bool use_ip;
61  bool use_port;
62};
63
64// Implements the NAT device.  It listens for packets on the internal network,
65// translates them, and sends them out over the external network.
66
67const int NAT_SERVER_PORT = 4237;
68
69class NATServer : public sigslot::has_slots<> {
70 public:
71  NATServer(
72      NATType type, SocketFactory* internal, const SocketAddress& internal_addr,
73      SocketFactory* external, const SocketAddress& external_ip);
74  ~NATServer();
75
76  SocketAddress internal_address() const {
77    return server_socket_->GetLocalAddress();
78  }
79
80  // Packets received on one of the networks.
81  void OnInternalPacket(AsyncPacketSocket* socket, const char* buf,
82                        size_t size, const SocketAddress& addr);
83  void OnExternalPacket(AsyncPacketSocket* socket, const char* buf,
84                        size_t size, const SocketAddress& remote_addr);
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    SocketAddressPair route;
95    AsyncUDPSocket* socket;
96    AddressSet* whitelist;
97  };
98
99  typedef std::map<SocketAddressPair, TransEntry*, RouteCmp> InternalMap;
100  typedef std::map<SocketAddress, TransEntry*> ExternalMap;
101
102  /* Creates a new entry that translates the given route. */
103  void Translate(const SocketAddressPair& route);
104
105  /* Determines whether the NAT would filter out a packet from this address. */
106  bool Filter(TransEntry* entry, const SocketAddress& ext_addr);
107
108  NAT* nat_;
109  SocketFactory* internal_;
110  SocketFactory* external_;
111  SocketAddress external_ip_;
112  AsyncUDPSocket* server_socket_;
113  AsyncSocket* tcp_server_socket_;
114  InternalMap* int_map_;
115  ExternalMap* ext_map_;
116  DISALLOW_EVIL_CONSTRUCTORS(NATServer);
117};
118
119}  // namespace talk_base
120
121#endif  // TALK_BASE_NATSERVER_H_
122