natserver.h

本人收集整理的一份c/c++跨平台网络库

#ifndef UTILS_BASE_NATSERVER_H_
#define UTILS_BASE_NATSERVER_H_

#include "asyncudpsocket.h"
#include "socketaddresspair.h"
#include "thread.h"
#include "socketfactory.h"
#include "nattypes.h"
#include <map>

namespace utils_base {

// 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 {
  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 {
  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();

  // Packets received on one of the networks.
  void OnInternalPacket(
      const char* buf, size_t size, const SocketAddress& addr,
      AsyncPacketSocket* socket);
  void OnExternalPacket(
      const char* buf, size_t size, const SocketAddress& remote_addr,
      AsyncPacketSocket* socket);

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();

    SocketAddressPair route;
    AsyncUDPSocket* socket;
    AddressSet* whitelist;
  };

  typedef std::map<SocketAddressPair,TransEntry*,RouteCmp> InternalMap;
  typedef std::map<SocketAddress,TransEntry*> ExternalMap;

  NAT* nat_;
  AsyncUDPSocket* server_socket_;
  SocketFactory* external_;
  SocketAddress external_ip_;
  InternalMap* int_map_;
  ExternalMap* ext_map_;

  /* 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 Filter(TransEntry* entry, const SocketAddress& ext_addr);
};

} // namespace utils_base

#endif // UTILS_BASE_NATSERVER_H_