src/lib/encode_server_finder.cc

   1 /*
   2     Copyright (C) 2013-2018 Carl Hetherington <cth@carlh.net>
   3
   4     This file is part of DCP-o-matic.
   5
   6     DCP-o-matic is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     DCP-o-matic is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 */
  20
  21 #include "encode_server_finder.h"
  22 #include "exceptions.h"
  23 #include "util.h"
  24 #include "config.h"
  25 #include "cross.h"
  26 #include "encode_server_description.h"
  27 #include "dcpomatic_socket.h"
  28 #include <dcp/raw_convert.h>
  29 #include <libcxml/cxml.h>
  30 #include <boost/bind/placeholders.hpp>
  31 #include <boost/lambda/lambda.hpp>
  32 #include <iostream>
  33
  34 #include "i18n.h"
  35
  36 using std::string;
  37 using std::list;
  38 using std::vector;
  39 using std::cout;
  40 using boost::shared_ptr;
  41 using boost::scoped_array;
  42 using boost::weak_ptr;
  43 using boost::optional;
  44 #if BOOST_VERSION >= 106100
  45 using namespace boost::placeholders;
  46 #endif
  47 using dcp::raw_convert;
  48
  49 EncodeServerFinder* EncodeServerFinder::_instance = 0;
  50
  51 EncodeServerFinder::EncodeServerFinder ()
  52         : _search_thread (0)
  53         , _listen_thread (0)
  54         , _stop (false)
  55 {
  56         Config::instance()->Changed.connect (boost::bind (&EncodeServerFinder::config_changed, this, _1));
  57 }
  58
  59 void
  60 EncodeServerFinder::start ()
  61 {
  62         _search_thread = new boost::thread (boost::bind (&EncodeServerFinder::search_thread, this));
  63         _listen_thread = new boost::thread (boost::bind (&EncodeServerFinder::listen_thread, this));
  64 #ifdef DCPOMATIC_LINUX
  65         pthread_setname_np (_search_thread->native_handle(), "encode-server-search");
  66         pthread_setname_np (_listen_thread->native_handle(), "encode-server-listen");
  67 #endif
  68 }
  69
  70
  71 EncodeServerFinder::~EncodeServerFinder ()
  72 {
  73         stop ();
  74 }
  75
  76 void
  77 EncodeServerFinder::stop ()
  78 {
  79         _stop = true;
  80
  81         _search_condition.notify_all ();
  82         if (_search_thread) {
  83                 /* Ideally this would be a DCPOMATIC_ASSERT(_search_thread->joinable()) but we
  84                    can't throw exceptions from a destructor.
  85                 */
  86                 if (_search_thread->joinable ()) {
  87                         _search_thread->join ();
  88                 }
  89         }
  90         delete _search_thread;
  91         _search_thread = 0;
  92
  93         _listen_io_service.stop ();
  94         if (_listen_thread) {
  95                 /* Ideally this would be a DCPOMATIC_ASSERT(_listen_thread->joinable()) but we
  96                    can't throw exceptions from a destructor.
  97                 */
  98                 if (_listen_thread->joinable ()) {
  99                         _listen_thread->join ();
 100                 }
 101         }
 102         delete _listen_thread;
 103         _listen_thread = 0;
 104
 105         boost::mutex::scoped_lock lm (_servers_mutex);
 106         _servers.clear ();
 107 }
 108
 109 void
 110 EncodeServerFinder::search_thread ()
 111 try
 112 {
 113         boost::system::error_code error;
 114         boost::asio::io_service io_service;
 115         boost::asio::ip::udp::socket socket (io_service);
 116         socket.open (boost::asio::ip::udp::v4(), error);
 117         if (error) {
 118                 throw NetworkError ("failed to set up broadcast socket");
 119         }
 120
 121         socket.set_option (boost::asio::ip::udp::socket::reuse_address (true));
 122         socket.set_option (boost::asio::socket_base::broadcast (true));
 123
 124         string const data = DCPOMATIC_HELLO;
 125         int const interval = 10;
 126
 127         while (!_stop) {
 128                 if (Config::instance()->use_any_servers ()) {
 129                         /* Broadcast to look for servers */
 130                         try {
 131                                 boost::asio::ip::udp::endpoint end_point (boost::asio::ip::address_v4::broadcast(), HELLO_PORT);
 132                                 socket.send_to (boost::asio::buffer (data.c_str(), data.size() + 1), end_point);
 133                         } catch (...) {
 134
 135                         }
 136                 }
 137
 138                 /* Query our `definite' servers (if there are any) */
 139                 vector<string> servers = Config::instance()->servers ();
 140                 for (vector<string>::const_iterator i = servers.begin(); i != servers.end(); ++i) {
 141                         if (server_found (*i)) {
 142                                 /* Don't bother asking a server that we already know about */
 143                                 continue;
 144                         }
 145                         try {
 146                                 boost::asio::ip::udp::resolver resolver (io_service);
 147                                 boost::asio::ip::udp::resolver::query query (*i, raw_convert<string> (HELLO_PORT));
 148                                 boost::asio::ip::udp::endpoint end_point (*resolver.resolve (query));
 149                                 socket.send_to (boost::asio::buffer (data.c_str(), data.size() + 1), end_point);
 150                         } catch (...) {
 151
 152                         }
 153                 }
 154
 155                 /* Discard servers that we haven't seen for a while */
 156                 bool removed = false;
 157                 {
 158                         boost::mutex::scoped_lock lm (_servers_mutex);
 159
 160                         list<EncodeServerDescription>::iterator i = _servers.begin();
 161                         while (i != _servers.end()) {
 162                                 if (i->last_seen_seconds() > 2 * interval) {
 163                                         list<EncodeServerDescription>::iterator j = i;
 164                                         ++j;
 165                                         _servers.erase (i);
 166                                         i = j;
 167                                         removed = true;
 168                                 } else {
 169                                         ++i;
 170                                 }
 171                         }
 172                 }
 173
 174                 if (removed) {
 175                         emit (boost::bind (boost::ref (ServersListChanged)));
 176                 }
 177
 178                 boost::mutex::scoped_lock lm (_search_condition_mutex);
 179                 _search_condition.timed_wait (lm, boost::get_system_time() + boost::posix_time::seconds (interval));
 180         }
 181 }
 182 catch (...)
 183 {
 184         store_current ();
 185 }
 186
 187 void
 188 EncodeServerFinder::listen_thread ()
 189 try {
 190         using namespace boost::asio::ip;
 191
 192         try {
 193                 _listen_acceptor.reset (
 194                         new tcp::acceptor (_listen_io_service, tcp::endpoint (tcp::v4(), is_batch_converter ? BATCH_SERVER_PRESENCE_PORT : MAIN_SERVER_PRESENCE_PORT))
 195                         );
 196         } catch (...) {
 197                 boost::throw_exception (NetworkError (_("Could not listen for remote encode servers.  Perhaps another instance of DCP-o-matic is running.")));
 198         }
 199
 200         start_accept ();
 201         _listen_io_service.run ();
 202 }
 203 catch (...)
 204 {
 205         store_current ();
 206 }
 207
 208 void
 209 EncodeServerFinder::start_accept ()
 210 {
 211         shared_ptr<Socket> socket (new Socket ());
 212         _listen_acceptor->async_accept (
 213                 socket->socket(),
 214                 boost::bind (&EncodeServerFinder::handle_accept, this, boost::asio::placeholders::error, socket)
 215                 );
 216 }
 217
 218 void
 219 EncodeServerFinder::handle_accept (boost::system::error_code ec, shared_ptr<Socket> socket)
 220 {
 221         if (ec) {
 222                 start_accept ();
 223                 return;
 224         }
 225
 226         uint32_t length;
 227         socket->read (reinterpret_cast<uint8_t*> (&length), sizeof (uint32_t));
 228         length = ntohl (length);
 229
 230         scoped_array<char> buffer (new char[length]);
 231         socket->read (reinterpret_cast<uint8_t*> (buffer.get()), length);
 232
 233         string s (buffer.get());
 234         shared_ptr<cxml::Document> xml (new cxml::Document ("ServerAvailable"));
 235         xml->read_string (s);
 236
 237         string const ip = socket->socket().remote_endpoint().address().to_string ();
 238         optional<list<EncodeServerDescription>::iterator> found = server_found (ip);
 239         if (found) {
 240                 (*found)->set_seen ();
 241         } else {
 242                 EncodeServerDescription sd (ip, xml->number_child<int>("Threads"), xml->optional_number_child<int>("Version").get_value_or(0));
 243                 {
 244                         boost::mutex::scoped_lock lm (_servers_mutex);
 245                         _servers.push_back (sd);
 246                 }
 247                 emit (boost::bind (boost::ref (ServersListChanged)));
 248         }
 249
 250         start_accept ();
 251 }
 252
 253 optional<list<EncodeServerDescription>::iterator>
 254 EncodeServerFinder::server_found (string ip)
 255 {
 256         boost::mutex::scoped_lock lm (_servers_mutex);
 257         list<EncodeServerDescription>::iterator i = _servers.begin();
 258         while (i != _servers.end() && i->host_name() != ip) {
 259                 ++i;
 260         }
 261
 262         if (i != _servers.end()) {
 263                 return i;
 264         }
 265
 266         return optional<list<EncodeServerDescription>::iterator>();
 267 }
 268
 269 EncodeServerFinder*
 270 EncodeServerFinder::instance ()
 271 {
 272         if (!_instance) {
 273                 _instance = new EncodeServerFinder ();
 274                 _instance->start ();
 275         }
 276
 277         return _instance;
 278 }
 279
 280 void
 281 EncodeServerFinder::drop ()
 282 {
 283         delete _instance;
 284         _instance = 0;
 285 }
 286
 287 list<EncodeServerDescription>
 288 EncodeServerFinder::servers () const
 289 {
 290         boost::mutex::scoped_lock lm (_servers_mutex);
 291         return _servers;
 292 }
 293
 294 void
 295 EncodeServerFinder::config_changed (Config::Property what)
 296 {
 297         if (what == Config::USE_ANY_SERVERS || what == Config::SERVERS) {
 298                 {
 299                         boost::mutex::scoped_lock lm (_servers_mutex);
 300                         _servers.clear ();
 301                 }
 302                 ServersListChanged ();
 303                 _search_condition.notify_all ();
 304         }
 305 }