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      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_NATSOCKETFACTORY_H_
     29 #define TALK_BASE_NATSOCKETFACTORY_H_
     30 
     31 #include <string>
     32 #include <map>
     33 #include <set>
     34 
     35 #include "talk/base/natserver.h"
     36 #include "talk/base/socketaddress.h"
     37 #include "talk/base/socketserver.h"
     38 
     39 namespace talk_base {
     40 
     41 const size_t kNATEncodedIPv4AddressSize = 8U;
     42 const size_t kNATEncodedIPv6AddressSize = 20U;
     43 
     44 // Used by the NAT socket implementation.
     45 class NATInternalSocketFactory {
     46  public:
     47   virtual ~NATInternalSocketFactory() {}
     48   virtual AsyncSocket* CreateInternalSocket(int family, int type,
     49       const SocketAddress& local_addr, SocketAddress* nat_addr) = 0;
     50 };
     51 
     52 // Creates sockets that will send all traffic through a NAT, using an existing
     53 // NATServer instance running at nat_addr. The actual data is sent using sockets
     54 // from a socket factory, given to the constructor.
     55 class NATSocketFactory : public SocketFactory, public NATInternalSocketFactory {
     56  public:
     57   NATSocketFactory(SocketFactory* factory, const SocketAddress& nat_addr);
     58 
     59   // SocketFactory implementation
     60   virtual Socket* CreateSocket(int type);
     61   virtual Socket* CreateSocket(int family, int type);
     62   virtual AsyncSocket* CreateAsyncSocket(int type);
     63   virtual AsyncSocket* CreateAsyncSocket(int family, int type);
     64 
     65   // NATInternalSocketFactory implementation
     66   virtual AsyncSocket* CreateInternalSocket(int family, int type,
     67       const SocketAddress& local_addr, SocketAddress* nat_addr);
     68 
     69  private:
     70   SocketFactory* factory_;
     71   SocketAddress nat_addr_;
     72   DISALLOW_EVIL_CONSTRUCTORS(NATSocketFactory);
     73 };
     74 
     75 // Creates sockets that will send traffic through a NAT depending on what
     76 // address they bind to. This can be used to simulate a client on a NAT sending
     77 // to a client that is not behind a NAT.
     78 // Note that the internal addresses of clients must be unique. This is because
     79 // there is only one socketserver per thread, and the Bind() address is used to
     80 // figure out which NAT (if any) the socket should talk to.
     81 //
     82 // Example with 3 NATs (2 cascaded), and 3 clients.
     83 // ss->AddTranslator("1.2.3.4", "192.168.0.1", NAT_ADDR_RESTRICTED);
     84 // ss->AddTranslator("99.99.99.99", "10.0.0.1", NAT_SYMMETRIC)->
     85 //     AddTranslator("10.0.0.2", "192.168.1.1", NAT_OPEN_CONE);
     86 // ss->GetTranslator("1.2.3.4")->AddClient("1.2.3.4", "192.168.0.2");
     87 // ss->GetTranslator("99.99.99.99")->AddClient("10.0.0.3");
     88 // ss->GetTranslator("99.99.99.99")->GetTranslator("10.0.0.2")->
     89 //     AddClient("192.168.1.2");
     90 class NATSocketServer : public SocketServer, public NATInternalSocketFactory {
     91  public:
     92   class Translator;
     93   // holds a list of NATs
     94   class TranslatorMap : private std::map<SocketAddress, Translator*> {
     95    public:
     96     ~TranslatorMap();
     97     Translator* Get(const SocketAddress& ext_ip);
     98     Translator* Add(const SocketAddress& ext_ip, Translator*);
     99     void Remove(const SocketAddress& ext_ip);
    100     Translator* FindClient(const SocketAddress& int_ip);
    101   };
    102 
    103   // a specific NAT
    104   class Translator {
    105    public:
    106     Translator(NATSocketServer* server, NATType type,
    107                const SocketAddress& int_addr, SocketFactory* ext_factory,
    108                const SocketAddress& ext_addr);
    109 
    110     SocketFactory* internal_factory() { return internal_factory_.get(); }
    111     SocketAddress internal_address() const {
    112       return nat_server_->internal_address();
    113     }
    114     SocketAddress internal_tcp_address() const {
    115       return SocketAddress();  // nat_server_->internal_tcp_address();
    116     }
    117 
    118     Translator* GetTranslator(const SocketAddress& ext_ip);
    119     Translator* AddTranslator(const SocketAddress& ext_ip,
    120                               const SocketAddress& int_ip, NATType type);
    121     void RemoveTranslator(const SocketAddress& ext_ip);
    122 
    123     bool AddClient(const SocketAddress& int_ip);
    124     void RemoveClient(const SocketAddress& int_ip);
    125 
    126     // Looks for the specified client in this or a child NAT.
    127     Translator* FindClient(const SocketAddress& int_ip);
    128 
    129    private:
    130     NATSocketServer* server_;
    131     scoped_ptr<SocketFactory> internal_factory_;
    132     scoped_ptr<NATServer> nat_server_;
    133     TranslatorMap nats_;
    134     std::set<SocketAddress> clients_;
    135   };
    136 
    137   explicit NATSocketServer(SocketServer* ss);
    138 
    139   SocketServer* socketserver() { return server_; }
    140   MessageQueue* queue() { return msg_queue_; }
    141 
    142   Translator* GetTranslator(const SocketAddress& ext_ip);
    143   Translator* AddTranslator(const SocketAddress& ext_ip,
    144                             const SocketAddress& int_ip, NATType type);
    145   void RemoveTranslator(const SocketAddress& ext_ip);
    146 
    147   // SocketServer implementation
    148   virtual Socket* CreateSocket(int type);
    149   virtual Socket* CreateSocket(int family, int type);
    150 
    151   virtual AsyncSocket* CreateAsyncSocket(int type);
    152   virtual AsyncSocket* CreateAsyncSocket(int family, int type);
    153 
    154   virtual void SetMessageQueue(MessageQueue* queue) {
    155     msg_queue_ = queue;
    156     server_->SetMessageQueue(queue);
    157   }
    158   virtual bool Wait(int cms, bool process_io) {
    159     return server_->Wait(cms, process_io);
    160   }
    161   virtual void WakeUp() {
    162     server_->WakeUp();
    163   }
    164 
    165   // NATInternalSocketFactory implementation
    166   virtual AsyncSocket* CreateInternalSocket(int family, int type,
    167       const SocketAddress& local_addr, SocketAddress* nat_addr);
    168 
    169  private:
    170   SocketServer* server_;
    171   MessageQueue* msg_queue_;
    172   TranslatorMap nats_;
    173   DISALLOW_EVIL_CONSTRUCTORS(NATSocketServer);
    174 };
    175 
    176 // Free-standing NAT helper functions.
    177 size_t PackAddressForNAT(char* buf, size_t buf_size,
    178                          const SocketAddress& remote_addr);
    179 size_t UnpackAddressFromNAT(const char* buf, size_t buf_size,
    180                             SocketAddress* remote_addr);
    181 }  // namespace talk_base
    182 
    183 #endif  // TALK_BASE_NATSOCKETFACTORY_H_
    184