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      1 /*
      2  *  Copyright 2012 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_P2P_BASE_TURNSERVER_H_
     12 #define WEBRTC_P2P_BASE_TURNSERVER_H_
     13 
     14 #include <list>
     15 #include <map>
     16 #include <set>
     17 #include <string>
     18 
     19 #include "webrtc/p2p/base/portinterface.h"
     20 #include "webrtc/base/asyncpacketsocket.h"
     21 #include "webrtc/base/messagequeue.h"
     22 #include "webrtc/base/sigslot.h"
     23 #include "webrtc/base/socketaddress.h"
     24 
     25 namespace rtc {
     26 class ByteBuffer;
     27 class PacketSocketFactory;
     28 class Thread;
     29 }
     30 
     31 namespace cricket {
     32 
     33 class StunMessage;
     34 class TurnMessage;
     35 class TurnServer;
     36 
     37 // The default server port for TURN, as specified in RFC5766.
     38 const int TURN_SERVER_PORT = 3478;
     39 
     40 // Encapsulates the client's connection to the server.
     41 class TurnServerConnection {
     42  public:
     43   TurnServerConnection() : proto_(PROTO_UDP), socket_(NULL) {}
     44   TurnServerConnection(const rtc::SocketAddress& src,
     45                        ProtocolType proto,
     46                        rtc::AsyncPacketSocket* socket);
     47   const rtc::SocketAddress& src() const { return src_; }
     48   rtc::AsyncPacketSocket* socket() { return socket_; }
     49   bool operator==(const TurnServerConnection& t) const;
     50   bool operator<(const TurnServerConnection& t) const;
     51   std::string ToString() const;
     52 
     53  private:
     54   rtc::SocketAddress src_;
     55   rtc::SocketAddress dst_;
     56   cricket::ProtocolType proto_;
     57   rtc::AsyncPacketSocket* socket_;
     58 };
     59 
     60 // Encapsulates a TURN allocation.
     61 // The object is created when an allocation request is received, and then
     62 // handles TURN messages (via HandleTurnMessage) and channel data messages
     63 // (via HandleChannelData) for this allocation when received by the server.
     64 // The object self-deletes and informs the server if its lifetime timer expires.
     65 class TurnServerAllocation : public rtc::MessageHandler,
     66                              public sigslot::has_slots<> {
     67  public:
     68   TurnServerAllocation(TurnServer* server_,
     69                        rtc::Thread* thread,
     70                        const TurnServerConnection& conn,
     71                        rtc::AsyncPacketSocket* server_socket,
     72                        const std::string& key);
     73   virtual ~TurnServerAllocation();
     74 
     75   TurnServerConnection* conn() { return &conn_; }
     76   const std::string& key() const { return key_; }
     77   const std::string& transaction_id() const { return transaction_id_; }
     78   const std::string& username() const { return username_; }
     79   const std::string& origin() const { return origin_; }
     80   const std::string& last_nonce() const { return last_nonce_; }
     81   void set_last_nonce(const std::string& nonce) { last_nonce_ = nonce; }
     82 
     83   std::string ToString() const;
     84 
     85   void HandleTurnMessage(const TurnMessage* msg);
     86   void HandleChannelData(const char* data, size_t size);
     87 
     88   sigslot::signal1<TurnServerAllocation*> SignalDestroyed;
     89 
     90  private:
     91   class Channel;
     92   class Permission;
     93   typedef std::list<Permission*> PermissionList;
     94   typedef std::list<Channel*> ChannelList;
     95 
     96   void HandleAllocateRequest(const TurnMessage* msg);
     97   void HandleRefreshRequest(const TurnMessage* msg);
     98   void HandleSendIndication(const TurnMessage* msg);
     99   void HandleCreatePermissionRequest(const TurnMessage* msg);
    100   void HandleChannelBindRequest(const TurnMessage* msg);
    101 
    102   void OnExternalPacket(rtc::AsyncPacketSocket* socket,
    103                         const char* data, size_t size,
    104                         const rtc::SocketAddress& addr,
    105                         const rtc::PacketTime& packet_time);
    106 
    107   static int ComputeLifetime(const TurnMessage* msg);
    108   bool HasPermission(const rtc::IPAddress& addr);
    109   void AddPermission(const rtc::IPAddress& addr);
    110   Permission* FindPermission(const rtc::IPAddress& addr) const;
    111   Channel* FindChannel(int channel_id) const;
    112   Channel* FindChannel(const rtc::SocketAddress& addr) const;
    113 
    114   void SendResponse(TurnMessage* msg);
    115   void SendBadRequestResponse(const TurnMessage* req);
    116   void SendErrorResponse(const TurnMessage* req, int code,
    117                          const std::string& reason);
    118   void SendExternal(const void* data, size_t size,
    119                     const rtc::SocketAddress& peer);
    120 
    121   void OnPermissionDestroyed(Permission* perm);
    122   void OnChannelDestroyed(Channel* channel);
    123   virtual void OnMessage(rtc::Message* msg);
    124 
    125   TurnServer* server_;
    126   rtc::Thread* thread_;
    127   TurnServerConnection conn_;
    128   rtc::scoped_ptr<rtc::AsyncPacketSocket> external_socket_;
    129   std::string key_;
    130   std::string transaction_id_;
    131   std::string username_;
    132   std::string origin_;
    133   std::string last_nonce_;
    134   PermissionList perms_;
    135   ChannelList channels_;
    136 };
    137 
    138 // An interface through which the MD5 credential hash can be retrieved.
    139 class TurnAuthInterface {
    140  public:
    141   // Gets HA1 for the specified user and realm.
    142   // HA1 = MD5(A1) = MD5(username:realm:password).
    143   // Return true if the given username and realm are valid, or false if not.
    144   virtual bool GetKey(const std::string& username, const std::string& realm,
    145                       std::string* key) = 0;
    146 };
    147 
    148 // An interface enables Turn Server to control redirection behavior.
    149 class TurnRedirectInterface {
    150  public:
    151   virtual bool ShouldRedirect(const rtc::SocketAddress& address,
    152                               rtc::SocketAddress* out) = 0;
    153   virtual ~TurnRedirectInterface() {}
    154 };
    155 
    156 // The core TURN server class. Give it a socket to listen on via
    157 // AddInternalServerSocket, and a factory to create external sockets via
    158 // SetExternalSocketFactory, and it's ready to go.
    159 // Not yet wired up: TCP support.
    160 class TurnServer : public sigslot::has_slots<> {
    161  public:
    162   typedef std::map<TurnServerConnection, TurnServerAllocation*> AllocationMap;
    163 
    164   explicit TurnServer(rtc::Thread* thread);
    165   ~TurnServer();
    166 
    167   // Gets/sets the realm value to use for the server.
    168   const std::string& realm() const { return realm_; }
    169   void set_realm(const std::string& realm) { realm_ = realm; }
    170 
    171   // Gets/sets the value for the SOFTWARE attribute for TURN messages.
    172   const std::string& software() const { return software_; }
    173   void set_software(const std::string& software) { software_ = software; }
    174 
    175   const AllocationMap& allocations() const { return allocations_; }
    176 
    177   // Sets the authentication callback; does not take ownership.
    178   void set_auth_hook(TurnAuthInterface* auth_hook) { auth_hook_ = auth_hook; }
    179 
    180   void set_redirect_hook(TurnRedirectInterface* redirect_hook) {
    181     redirect_hook_ = redirect_hook;
    182   }
    183 
    184   void set_enable_otu_nonce(bool enable) { enable_otu_nonce_ = enable; }
    185 
    186   // If set to true, reject CreatePermission requests to RFC1918 addresses.
    187   void set_reject_private_addresses(bool filter) {
    188     reject_private_addresses_ = filter;
    189   }
    190 
    191   // Starts listening for packets from internal clients.
    192   void AddInternalSocket(rtc::AsyncPacketSocket* socket,
    193                          ProtocolType proto);
    194   // Starts listening for the connections on this socket. When someone tries
    195   // to connect, the connection will be accepted and a new internal socket
    196   // will be added.
    197   void AddInternalServerSocket(rtc::AsyncSocket* socket,
    198                                ProtocolType proto);
    199   // Specifies the factory to use for creating external sockets.
    200   void SetExternalSocketFactory(rtc::PacketSocketFactory* factory,
    201                                 const rtc::SocketAddress& address);
    202 
    203  private:
    204   void OnInternalPacket(rtc::AsyncPacketSocket* socket, const char* data,
    205                         size_t size, const rtc::SocketAddress& address,
    206                         const rtc::PacketTime& packet_time);
    207 
    208   void OnNewInternalConnection(rtc::AsyncSocket* socket);
    209 
    210   // Accept connections on this server socket.
    211   void AcceptConnection(rtc::AsyncSocket* server_socket);
    212   void OnInternalSocketClose(rtc::AsyncPacketSocket* socket, int err);
    213 
    214   void HandleStunMessage(
    215       TurnServerConnection* conn, const char* data, size_t size);
    216   void HandleBindingRequest(TurnServerConnection* conn, const StunMessage* msg);
    217   void HandleAllocateRequest(TurnServerConnection* conn, const TurnMessage* msg,
    218                              const std::string& key);
    219 
    220   bool GetKey(const StunMessage* msg, std::string* key);
    221   bool CheckAuthorization(TurnServerConnection* conn, const StunMessage* msg,
    222                           const char* data, size_t size,
    223                           const std::string& key);
    224   std::string GenerateNonce() const;
    225   bool ValidateNonce(const std::string& nonce) const;
    226 
    227   TurnServerAllocation* FindAllocation(TurnServerConnection* conn);
    228   TurnServerAllocation* CreateAllocation(
    229       TurnServerConnection* conn, int proto, const std::string& key);
    230 
    231   void SendErrorResponse(TurnServerConnection* conn, const StunMessage* req,
    232                          int code, const std::string& reason);
    233 
    234   void SendErrorResponseWithRealmAndNonce(TurnServerConnection* conn,
    235                                           const StunMessage* req,
    236                                           int code,
    237                                           const std::string& reason);
    238 
    239   void SendErrorResponseWithAlternateServer(TurnServerConnection* conn,
    240                                             const StunMessage* req,
    241                                             const rtc::SocketAddress& addr);
    242 
    243   void SendStun(TurnServerConnection* conn, StunMessage* msg);
    244   void Send(TurnServerConnection* conn, const rtc::ByteBuffer& buf);
    245 
    246   void OnAllocationDestroyed(TurnServerAllocation* allocation);
    247   void DestroyInternalSocket(rtc::AsyncPacketSocket* socket);
    248 
    249   typedef std::map<rtc::AsyncPacketSocket*,
    250                    ProtocolType> InternalSocketMap;
    251   typedef std::map<rtc::AsyncSocket*,
    252                    ProtocolType> ServerSocketMap;
    253 
    254   rtc::Thread* thread_;
    255   std::string nonce_key_;
    256   std::string realm_;
    257   std::string software_;
    258   TurnAuthInterface* auth_hook_;
    259   TurnRedirectInterface* redirect_hook_;
    260   // otu - one-time-use. Server will respond with 438 if it's
    261   // sees the same nonce in next transaction.
    262   bool enable_otu_nonce_;
    263   bool reject_private_addresses_ = false;
    264 
    265   InternalSocketMap server_sockets_;
    266   ServerSocketMap server_listen_sockets_;
    267   rtc::scoped_ptr<rtc::PacketSocketFactory>
    268       external_socket_factory_;
    269   rtc::SocketAddress external_addr_;
    270 
    271   AllocationMap allocations_;
    272 
    273   friend class TurnServerAllocation;
    274 };
    275 
    276 }  // namespace cricket
    277 
    278 #endif  // WEBRTC_P2P_BASE_TURNSERVER_H_
    279