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