src/lib/encode_server_finder.cc

   1 /*
   2     Copyright (C) 2013-2021 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
  22 #include "config.h"
  23 #include "constants.h"
  24 #include "cross.h"
  25 #include "dcpomatic_socket.h"
  26 #include "encode_server_description.h"
  27 #include "encode_server_finder.h"
  28 #include "exceptions.h"
  29 #include <dcp/raw_convert.h>
  30 #include <libcxml/cxml.h>
  31 #include <boost/bind/placeholders.hpp>
  32 #include <boost/lambda/lambda.hpp>
  33 #include <iostream>
  34
  35 #include "i18n.h"
  36
  37
  38 using std::cout;
  39 using std::list;
  40 using std::make_shared;
  41 using std::shared_ptr;
  42 using std::string;
  43 using std::vector;
  44 using std::weak_ptr;
  45 using boost::optional;
  46 using boost::scoped_array;
  47 #if BOOST_VERSION >= 106100
  48 using namespace boost::placeholders;
  49 #endif
  50 using dcp::raw_convert;
  51
  52
  53 EncodeServerFinder* EncodeServerFinder::_instance = 0;
  54
  55
  56 EncodeServerFinder::EncodeServerFinder ()
  57         : _stop (false)
  58 {
  59         Config::instance()->Changed.connect (boost::bind (&EncodeServerFinder::config_changed, this, _1));
  60 }
  61
  62
  63 void
  64 EncodeServerFinder::start ()
  65 {
  66         _search_thread = boost::thread (boost::bind(&EncodeServerFinder::search_thread, this));
  67         _listen_thread = boost::thread (boost::bind(&EncodeServerFinder::listen_thread, this));
  68 #ifdef DCPOMATIC_LINUX
  69         pthread_setname_np (_search_thread.native_handle(), "encode-server-search");
  70         pthread_setname_np (_listen_thread.native_handle(), "encode-server-listen");
  71 #endif
  72 }
  73
  74
  75 EncodeServerFinder::~EncodeServerFinder ()
  76 {
  77         stop ();
  78 }
  79
  80
  81 void
  82 EncodeServerFinder::stop ()
  83 {
  84         boost::this_thread::disable_interruption dis;
  85
  86         _stop = true;
  87
  88         _search_condition.notify_all ();
  89         try {
  90                 _search_thread.join();
  91         } catch (...) {}
  92
  93         _listen_io_service.stop ();
  94         try {
  95                 _listen_thread.join ();
  96         } catch (...) {}
  97
  98         boost::mutex::scoped_lock lm (_servers_mutex);
  99         _servers.clear ();
 100 }
 101
 102
 103 void
 104 EncodeServerFinder::search_thread ()
 105 try
 106 {
 107         start_of_thread ("EncodeServerFinder-search");
 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                 for (auto const& i: Config::instance()->servers()) {
 136                         try {
 137                                 boost::asio::ip::udp::resolver resolver (io_service);
 138                                 boost::asio::ip::udp::resolver::query query (i, raw_convert<string>(HELLO_PORT));
 139                                 boost::asio::ip::udp::endpoint end_point (*resolver.resolve(query));
 140                                 socket.send_to (boost::asio::buffer(data.c_str(), data.size() + 1), end_point);
 141                         } catch (...) {
 142
 143                         }
 144                 }
 145
 146                 /* Discard servers that we haven't seen for a while */
 147                 bool removed = false;
 148                 {
 149                         boost::mutex::scoped_lock lm (_servers_mutex);
 150
 151                         auto i = _servers.begin();
 152                         while (i != _servers.end()) {
 153                                 if (i->last_seen_seconds() > 2 * interval) {
 154                                         auto j = i;
 155                                         ++j;
 156                                         _servers.erase (i);
 157                                         i = j;
 158                                         removed = true;
 159                                 } else {
 160                                         ++i;
 161                                 }
 162                         }
 163                 }
 164
 165                 if (removed) {
 166                         emit (boost::bind(boost::ref(ServersListChanged)));
 167                 }
 168
 169                 boost::mutex::scoped_lock lm (_search_condition_mutex);
 170                 _search_condition.timed_wait (lm, boost::get_system_time() + boost::posix_time::seconds(interval));
 171         }
 172 }
 173 catch (...)
 174 {
 175         store_current ();
 176 }
 177
 178
 179 void
 180 EncodeServerFinder::listen_thread ()
 181 try {
 182         start_of_thread ("EncodeServerFinder-listen");
 183
 184         using namespace boost::asio::ip;
 185
 186         try {
 187                 _listen_acceptor.reset (
 188                         new tcp::acceptor (_listen_io_service, tcp::endpoint(tcp::v4(), is_batch_converter ? BATCH_SERVER_PRESENCE_PORT : MAIN_SERVER_PRESENCE_PORT))
 189                         );
 190         } catch (...) {
 191                 boost::throw_exception (NetworkError (_("Could not listen for remote encode servers.  Perhaps another instance of DCP-o-matic is running.")));
 192         }
 193
 194         start_accept ();
 195         _listen_io_service.run ();
 196 }
 197 catch (...)
 198 {
 199         store_current ();
 200 }
 201
 202
 203 void
 204 EncodeServerFinder::start_accept ()
 205 {
 206         _accept_socket = make_shared<Socket>();
 207
 208         _listen_acceptor->async_accept (
 209                 _accept_socket->socket(),
 210                 boost::bind(&EncodeServerFinder::handle_accept, this, boost::asio::placeholders::error)
 211                 );
 212 }
 213
 214
 215 void
 216 EncodeServerFinder::handle_accept (boost::system::error_code ec)
 217 {
 218         if (ec) {
 219                 start_accept ();
 220                 return;
 221         }
 222
 223         string server_available;
 224
 225         try {
 226                 uint32_t length;
 227                 _accept_socket->read (reinterpret_cast<uint8_t*>(&length), sizeof(uint32_t));
 228                 length = ntohl (length);
 229
 230                 if (length > 65536) {
 231                         start_accept();
 232                         return;
 233                 }
 234
 235                 scoped_array<char> buffer(new char[length]);
 236                 _accept_socket->read (reinterpret_cast<uint8_t*>(buffer.get()), length);
 237                 server_available = buffer.get();
 238         } catch (NetworkError&) {
 239                 /* Maybe the server went away; let's just try again */
 240                 start_accept();
 241                 return;
 242         }
 243
 244         auto xml = make_shared<cxml::Document>("ServerAvailable");
 245         xml->read_string(server_available);
 246
 247         auto const ip = _accept_socket->socket().remote_endpoint().address().to_string();
 248         bool changed = false;
 249         {
 250                 boost::mutex::scoped_lock lm (_servers_mutex);
 251                 auto i = _servers.begin();
 252                 while (i != _servers.end() && i->host_name() != ip) {
 253                         ++i;
 254                 }
 255
 256                 if (i != _servers.end()) {
 257                         i->set_seen();
 258                 } else {
 259                         EncodeServerDescription sd (ip, xml->number_child<int>("Threads"), xml->optional_number_child<int>("Version").get_value_or(0));
 260                         _servers.push_back (sd);
 261                         changed = true;
 262                 }
 263         }
 264
 265         if (changed) {
 266                 emit (boost::bind(boost::ref (ServersListChanged)));
 267         }
 268
 269         start_accept ();
 270 }
 271
 272
 273 EncodeServerFinder*
 274 EncodeServerFinder::instance ()
 275 {
 276         if (!_instance) {
 277                 _instance = new EncodeServerFinder ();
 278                 _instance->start ();
 279         }
 280
 281         return _instance;
 282 }
 283
 284
 285 void
 286 EncodeServerFinder::drop ()
 287 {
 288         delete _instance;
 289         _instance = nullptr;
 290 }
 291
 292
 293 list<EncodeServerDescription>
 294 EncodeServerFinder::servers () const
 295 {
 296         boost::mutex::scoped_lock lm (_servers_mutex);
 297         return _servers;
 298 }
 299
 300
 301 void
 302 EncodeServerFinder::config_changed (Config::Property what)
 303 {
 304         if (what == Config::USE_ANY_SERVERS || what == Config::SERVERS) {
 305                 {
 306                         boost::mutex::scoped_lock lm (_servers_mutex);
 307                         _servers.clear ();
 308                 }
 309                 ServersListChanged ();
 310                 _search_condition.notify_all ();
 311         }
 312 }