src/lib/server_finder.cc

   1 /*
   2     Copyright (C) 2013 Carl Hetherington <cth@carlh.net>
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17
  18 */
  19
  20 #include <libcxml/cxml.h>
  21 #include "server_finder.h"
  22 #include "exceptions.h"
  23 #include "util.h"
  24 #include "config.h"
  25 #include "cross.h"
  26 #include "ui_signaller.h"
  27
  28 using std::string;
  29 using std::stringstream;
  30 using std::list;
  31 using std::vector;
  32 using std::cout;
  33 using boost::shared_ptr;
  34 using boost::scoped_array;
  35 using boost::lexical_cast;
  36
  37 ServerFinder* ServerFinder::_instance = 0;
  38
  39 ServerFinder::ServerFinder ()
  40         : _disabled (false)
  41         , _broadcast_thread (0)
  42         , _listen_thread (0)
  43 {
  44         _broadcast_thread = new boost::thread (boost::bind (&ServerFinder::broadcast_thread, this));
  45         _listen_thread = new boost::thread (boost::bind (&ServerFinder::listen_thread, this));
  46 }
  47
  48 void
  49 ServerFinder::broadcast_thread ()
  50 {
  51         boost::system::error_code error;
  52         boost::asio::io_service io_service;
  53         boost::asio::ip::udp::socket socket (io_service);
  54         socket.open (boost::asio::ip::udp::v4(), error);
  55         if (error) {
  56                 throw NetworkError ("failed to set up broadcast socket");
  57         }
  58
  59         socket.set_option (boost::asio::ip::udp::socket::reuse_address (true));
  60         socket.set_option (boost::asio::socket_base::broadcast (true));
  61
  62         string const data = DCPOMATIC_HELLO;
  63
  64         while (1) {
  65                 if (Config::instance()->use_any_servers ()) {
  66                         /* Broadcast to look for servers */
  67                         boost::asio::ip::udp::endpoint end_point (boost::asio::ip::address_v4::broadcast(), Config::instance()->server_port_base() + 1);
  68                         socket.send_to (boost::asio::buffer (data.c_str(), data.size() + 1), end_point);
  69                 }
  70
  71                 /* Query our `definite' servers (if there are any) */
  72                 vector<string> servers = Config::instance()->servers ();
  73                 for (vector<string>::const_iterator i = servers.begin(); i != servers.end(); ++i) {
  74                         if (server_found (*i)) {
  75                                 /* Don't bother asking a server that we already know about */
  76                                 continue;
  77                         }
  78                         try {
  79                                 boost::asio::ip::udp::resolver resolver (io_service);
  80                                 boost::asio::ip::udp::resolver::query query (*i, lexical_cast<string> (Config::instance()->server_port_base() + 1));
  81                                 boost::asio::ip::udp::endpoint end_point (*resolver.resolve (query));
  82                                 socket.send_to (boost::asio::buffer (data.c_str(), data.size() + 1), end_point);
  83                         } catch (...) {
  84
  85                         }
  86                 }
  87
  88                 dcpomatic_sleep (10);
  89         }
  90 }
  91
  92 void
  93 ServerFinder::listen_thread ()
  94 {
  95         while (1) {
  96                 shared_ptr<Socket> sock (new Socket (10));
  97
  98                 try {
  99                         sock->accept (Config::instance()->server_port_base() + 1);
 100                 } catch (std::exception& e) {
 101                         continue;
 102                 }
 103
 104                 uint32_t length = sock->read_uint32 ();
 105                 scoped_array<char> buffer (new char[length]);
 106                 sock->read (reinterpret_cast<uint8_t*> (buffer.get()), length);
 107
 108                 stringstream s (buffer.get());
 109                 shared_ptr<cxml::Document> xml (new cxml::Document ("ServerAvailable"));
 110                 xml->read_stream (s);
 111
 112                 string const ip = sock->socket().remote_endpoint().address().to_string ();
 113                 if (!server_found (ip)) {
 114                         ServerDescription sd (ip, xml->number_child<int> ("Threads"));
 115                         _servers.push_back (sd);
 116                         ui_signaller->emit (boost::bind (boost::ref (ServerFound), sd));
 117                 }
 118         }
 119 }
 120
 121 bool
 122 ServerFinder::server_found (string ip) const
 123 {
 124         boost::mutex::scoped_lock lm (_mutex);
 125         list<ServerDescription>::const_iterator i = _servers.begin();
 126         while (i != _servers.end() && i->host_name() != ip) {
 127                 ++i;
 128         }
 129
 130         return i != _servers.end ();
 131 }
 132
 133 void
 134 ServerFinder::connect (boost::function<void (ServerDescription)> fn)
 135 {
 136         if (_disabled) {
 137                 return;
 138         }
 139
 140         boost::mutex::scoped_lock lm (_mutex);
 141
 142         /* Emit the current list of servers */
 143         for (list<ServerDescription>::iterator i = _servers.begin(); i != _servers.end(); ++i) {
 144                 fn (*i);
 145         }
 146
 147         ServerFound.connect (fn);
 148 }
 149
 150 ServerFinder*
 151 ServerFinder::instance ()
 152 {
 153         if (!_instance) {
 154                 _instance = new ServerFinder ();
 155         }
 156
 157         return _instance;
 158 }
 159
 160
 161