1 /*
2  *  Copyright 2004 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 RTC_BASE_PROXY_SERVER_H_
12 #define RTC_BASE_PROXY_SERVER_H_
13 
14 #include <memory>
15 #include <vector>
16 
17 #include "absl/memory/memory.h"
18 #include "rtc_base/async_socket.h"
19 #include "rtc_base/constructor_magic.h"
20 #include "rtc_base/memory/fifo_buffer.h"
21 #include "rtc_base/server_socket_adapters.h"
22 #include "rtc_base/socket_address.h"
23 
24 namespace rtc {
25 
26 class SocketFactory;
27 
28 // ProxyServer is a base class that allows for easy construction of proxy
29 // servers. With its helper class ProxyBinding, it contains all the necessary
30 // logic for receiving and bridging connections. The specific client-server
31 // proxy protocol is implemented by an instance of the AsyncProxyServerSocket
32 // class; children of ProxyServer implement WrapSocket appropriately to return
33 // the correct protocol handler.
34 
35 class ProxyBinding : public sigslot::has_slots<> {
36  public:
37   ProxyBinding(AsyncProxyServerSocket* in_socket, AsyncSocket* out_socket);
38   ~ProxyBinding() override;
39   sigslot::signal1<ProxyBinding*> SignalDestroyed;
40 
41  private:
42   void OnConnectRequest(AsyncProxyServerSocket* socket,
43                         const SocketAddress& addr);
44   void OnInternalRead(AsyncSocket* socket);
45   void OnInternalWrite(AsyncSocket* socket);
46   void OnInternalClose(AsyncSocket* socket, int err);
47   void OnExternalConnect(AsyncSocket* socket);
48   void OnExternalRead(AsyncSocket* socket);
49   void OnExternalWrite(AsyncSocket* socket);
50   void OnExternalClose(AsyncSocket* socket, int err);
51 
52   static void Read(AsyncSocket* socket, FifoBuffer* buffer);
53   static void Write(AsyncSocket* socket, FifoBuffer* buffer);
54   void Destroy();
55 
56   static const int kBufferSize = 4096;
57   std::unique_ptr<AsyncProxyServerSocket> int_socket_;
58   std::unique_ptr<AsyncSocket> ext_socket_;
59   bool connected_;
60   FifoBuffer out_buffer_;
61   FifoBuffer in_buffer_;
62   RTC_DISALLOW_COPY_AND_ASSIGN(ProxyBinding);
63 };
64 
65 class ProxyServer : public sigslot::has_slots<> {
66  public:
67   ProxyServer(SocketFactory* int_factory,
68               const SocketAddress& int_addr,
69               SocketFactory* ext_factory,
70               const SocketAddress& ext_ip);
71   ~ProxyServer() override;
72 
73   // Returns the address to which the proxy server is bound
74   SocketAddress GetServerAddress();
75 
76  protected:
77   void OnAcceptEvent(AsyncSocket* socket);
78   virtual AsyncProxyServerSocket* WrapSocket(AsyncSocket* socket) = 0;
79 
80  private:
81   SocketFactory* ext_factory_;
82   SocketAddress ext_ip_;
83   std::unique_ptr<AsyncSocket> server_socket_;
84   std::vector<std::unique_ptr<ProxyBinding>> bindings_;
85   RTC_DISALLOW_COPY_AND_ASSIGN(ProxyServer);
86 };
87 
88 // SocksProxyServer is a simple extension of ProxyServer to implement SOCKS.
89 class SocksProxyServer : public ProxyServer {
90  public:
SocksProxyServer(SocketFactory * int_factory,const SocketAddress & int_addr,SocketFactory * ext_factory,const SocketAddress & ext_ip)91   SocksProxyServer(SocketFactory* int_factory,
92                    const SocketAddress& int_addr,
93                    SocketFactory* ext_factory,
94                    const SocketAddress& ext_ip)
95       : ProxyServer(int_factory, int_addr, ext_factory, ext_ip) {}
96 
97  protected:
98   AsyncProxyServerSocket* WrapSocket(AsyncSocket* socket) override;
99   RTC_DISALLOW_COPY_AND_ASSIGN(SocksProxyServer);
100 };
101 
102 }  // namespace rtc
103 
104 #endif  // RTC_BASE_PROXY_SERVER_H_
105