Adds a modified copy of talk/base to webrtc/base. It is the first step in migrating talk/base to webrtc/base.

BUG=N/A
R=andrew@webrtc.org, wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/12199004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6107 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/base/natserver.h

@@ -0,0 +1,110 @@
+/*
+ *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_BASE_NATSERVER_H_
+#define WEBRTC_BASE_NATSERVER_H_
+
+#include <map>
+#include <set>
+
+#include "webrtc/base/asyncudpsocket.h"
+#include "webrtc/base/socketaddresspair.h"
+#include "webrtc/base/thread.h"
+#include "webrtc/base/socketfactory.h"
+#include "webrtc/base/nattypes.h"
+
+namespace rtc {
+
+// Change how routes (socketaddress pairs) are compared based on the type of
+// NAT.  The NAT server maintains a hashtable of the routes that it knows
+// about.  So these affect which routes are treated the same.
+struct RouteCmp {
+  explicit RouteCmp(NAT* nat);
+  size_t operator()(const SocketAddressPair& r) const;
+  bool operator()(
+      const SocketAddressPair& r1, const SocketAddressPair& r2) const;
+
+  bool symmetric;
+};
+
+// Changes how addresses are compared based on the filtering rules of the NAT.
+struct AddrCmp {
+  explicit AddrCmp(NAT* nat);
+  size_t operator()(const SocketAddress& r) const;
+  bool operator()(const SocketAddress& r1, const SocketAddress& r2) const;
+
+  bool use_ip;
+  bool use_port;
+};
+
+// Implements the NAT device.  It listens for packets on the internal network,
+// translates them, and sends them out over the external network.
+
+const int NAT_SERVER_PORT = 4237;
+
+class NATServer : public sigslot::has_slots<> {
+ public:
+  NATServer(
+      NATType type, SocketFactory* internal, const SocketAddress& internal_addr,
+      SocketFactory* external, const SocketAddress& external_ip);
+  ~NATServer();
+
+  SocketAddress internal_address() const {
+    return server_socket_->GetLocalAddress();
+  }
+
+  // Packets received on one of the networks.
+  void OnInternalPacket(AsyncPacketSocket* socket, const char* buf,
+                        size_t size, const SocketAddress& addr,
+                        const PacketTime& packet_time);
+  void OnExternalPacket(AsyncPacketSocket* socket, const char* buf,
+                        size_t size, const SocketAddress& remote_addr,
+                        const PacketTime& packet_time);
+
+ private:
+  typedef std::set<SocketAddress, AddrCmp> AddressSet;
+
+  /* Records a translation and the associated external socket. */
+  struct TransEntry {
+    TransEntry(const SocketAddressPair& r, AsyncUDPSocket* s, NAT* nat);
+    ~TransEntry();
+
+    void WhitelistInsert(const SocketAddress& addr);
+    bool WhitelistContains(const SocketAddress& ext_addr);
+
+    SocketAddressPair route;
+    AsyncUDPSocket* socket;
+    AddressSet* whitelist;
+    CriticalSection crit_;
+  };
+
+  typedef std::map<SocketAddressPair, TransEntry*, RouteCmp> InternalMap;
+  typedef std::map<SocketAddress, TransEntry*> ExternalMap;
+
+  /* Creates a new entry that translates the given route. */
+  void Translate(const SocketAddressPair& route);
+
+  /* Determines whether the NAT would filter out a packet from this address. */
+  bool ShouldFilterOut(TransEntry* entry, const SocketAddress& ext_addr);
+
+  NAT* nat_;
+  SocketFactory* internal_;
+  SocketFactory* external_;
+  SocketAddress external_ip_;
+  AsyncUDPSocket* server_socket_;
+  AsyncSocket* tcp_server_socket_;
+  InternalMap* int_map_;
+  ExternalMap* ext_map_;
+  DISALLOW_EVIL_CONSTRUCTORS(NATServer);
+};
+
+}  // namespace rtc
+
+#endif  // WEBRTC_BASE_NATSERVER_H_