Home | History | Annotate | Download | only in base 
      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 
     40 namespace 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.
     45 struct 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.
     55 struct 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 
     67 const int NAT_SERVER_PORT = 4237;
     68 
     69 class 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                         const PacketTime& packet_time);
     84   void OnExternalPacket(AsyncPacketSocket* socket, const char* buf,
     85                         size_t size, const SocketAddress& remote_addr,
     86                         const PacketTime& packet_time);
     87 
     88  private:
     89   typedef std::set<SocketAddress, AddrCmp> AddressSet;
     90 
     91   /* Records a translation and the associated external socket. */
     92   struct TransEntry {
     93     TransEntry(const SocketAddressPair& r, AsyncUDPSocket* s, NAT* nat);
     94     ~TransEntry();
     95 
     96     void WhitelistInsert(const SocketAddress& addr);
     97     bool WhitelistContains(const SocketAddress& ext_addr);
     98 
     99     SocketAddressPair route;
    100     AsyncUDPSocket* socket;
    101     AddressSet* whitelist;
    102     CriticalSection crit_;
    103   };
    104 
    105   typedef std::map<SocketAddressPair, TransEntry*, RouteCmp> InternalMap;
    106   typedef std::map<SocketAddress, TransEntry*> ExternalMap;
    107 
    108   /* Creates a new entry that translates the given route. */
    109   void Translate(const SocketAddressPair& route);
    110 
    111   /* Determines whether the NAT would filter out a packet from this address. */
    112   bool ShouldFilterOut(TransEntry* entry, const SocketAddress& ext_addr);
    113 
    114   NAT* nat_;
    115   SocketFactory* internal_;
    116   SocketFactory* external_;
    117   SocketAddress external_ip_;
    118   AsyncUDPSocket* server_socket_;
    119   AsyncSocket* tcp_server_socket_;
    120   InternalMap* int_map_;
    121   ExternalMap* ext_map_;
    122   DISALLOW_EVIL_CONSTRUCTORS(NATServer);
    123 };
    124 
    125 }  // namespace talk_base
    126 
    127 #endif  // TALK_BASE_NATSERVER_H_
    128