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 "variant.h"
  30 #include <dcp/raw_convert.h>
  31 #include <libcxml/cxml.h>
  32 #include <boost/bind/placeholders.hpp>
  33 #include <boost/lambda/lambda.hpp>
  34 #include <iostream>
  35
  36 #include "i18n.h"
  37
  38
  39 using std::cout;
  40 using std::list;
  41 using std::make_shared;
  42 using std::shared_ptr;
  43 using std::string;
  44 using std::vector;
  45 using std::weak_ptr;
  46 using boost::optional;
  47 using boost::scoped_array;
  48 #if BOOST_VERSION >= 106100
  49 using namespace boost::placeholders;
  50 #endif
  51 using dcp::raw_convert;
  52
  53
  54 EncodeServerFinder* EncodeServerFinder::_instance = 0;
  55
  56
  57 EncodeServerFinder::EncodeServerFinder ()
  58         : _stop (false)
  59 {
  60         Config::instance()->Changed.connect (boost::bind (&EncodeServerFinder::config_changed, this, _1));
  61 }
  62
  63
  64 void
  65 EncodeServerFinder::start ()
  66 {
  67         _search_thread = boost::thread (boost::bind(&EncodeServerFinder::search_thread, this));
  68         _listen_thread = boost::thread (boost::bind(&EncodeServerFinder::listen_thread, this));
  69 #ifdef DCPOMATIC_LINUX
  70         pthread_setname_np (_search_thread.native_handle(), "encode-server-search");
  71         pthread_setname_np (_listen_thread.native_handle(), "encode-server-listen");
  72 #endif
  73 }
  74
  75
  76 EncodeServerFinder::~EncodeServerFinder ()
  77 {
  78         stop ();
  79 }
  80
  81
  82 void
  83 EncodeServerFinder::stop ()
  84 {
  85         boost::this_thread::disable_interruption dis;
  86
  87         _stop = true;
  88
  89         _search_condition.notify_all ();
  90         try {
  91                 _search_thread.join();
  92         } catch (...) {}
  93
  94         _listen_io_service.stop ();
  95         try {
  96                 _listen_thread.join ();
  97         } catch (...) {}
  98
  99         boost::mutex::scoped_lock lm (_servers_mutex);
 100         _servers.clear ();
 101 }
 102
 103
 104 void
 105 EncodeServerFinder::search_thread ()
 106 try
 107 {
 108         start_of_thread ("EncodeServerFinder-search");
 109
 110         boost::system::error_code error;
 111         boost::asio::io_service io_service;
 112         boost::asio::ip::udp::socket socket (io_service);
 113         socket.open (boost::asio::ip::udp::v4(), error);
 114         if (error) {
 115                 throw NetworkError ("failed to set up broadcast socket");
 116         }
 117
 118         socket.set_option (boost::asio::ip::udp::socket::reuse_address(true));
 119         socket.set_option (boost::asio::socket_base::broadcast(true));
 120
 121         string const data = DCPOMATIC_HELLO;
 122         int const interval = 10;
 123
 124         while (!_stop) {
 125                 if (Config::instance()->use_any_servers()) {
 126                         /* Broadcast to look for servers */
 127                         try {
 128                                 boost::asio::ip::udp::endpoint end_point (boost::asio::ip::address_v4::broadcast(), HELLO_PORT);
 129                                 socket.send_to (boost::asio::buffer(data.c_str(), data.size() + 1), end_point);
 130                         } catch (...) {
 131
 132                         }
 133                 }
 134
 135                 /* Query our `definite' servers (if there are any) */
 136                 for (auto const& i: Config::instance()->servers()) {
 137                         try {
 138                                 boost::asio::ip::udp::resolver resolver (io_service);
 139                                 boost::asio::ip::udp::resolver::query query (i, raw_convert<string>(HELLO_PORT));
 140                                 boost::asio::ip::udp::endpoint end_point (*resolver.resolve(query));
 141                                 socket.send_to (boost::asio::buffer(data.c_str(), data.size() + 1), end_point);
 142                         } catch (...) {
 143
 144                         }
 145                 }
 146
 147                 /* Discard servers that we haven't seen for a while */
 148                 bool removed = false;
 149                 {
 150                         boost::mutex::scoped_lock lm (_servers_mutex);
 151
 152                         auto i = _servers.begin();
 153                         while (i != _servers.end()) {
 154                                 if (i->last_seen_seconds() > 2 * interval) {
 155                                         auto j = i;
 156                                         ++j;
 157                                         _servers.erase (i);
 158                                         i = j;
 159                                         removed = true;
 160                                 } else {
 161                                         ++i;
 162                                 }
 163                         }
 164                 }
 165
 166                 if (removed) {
 167                         emit (boost::bind(boost::ref(ServersListChanged)));
 168                 }
 169
 170                 boost::mutex::scoped_lock lm (_search_condition_mutex);
 171                 _search_condition.timed_wait (lm, boost::get_system_time() + boost::posix_time::seconds(interval));
 172         }
 173 }
 174 catch (...)
 175 {
 176         store_current ();
 177 }
 178
 179
 180 void
 181 EncodeServerFinder::listen_thread ()
 182 try {
 183         start_of_thread ("EncodeServerFinder-listen");
 184
 185         using namespace boost::asio::ip;
 186
 187         try {
 188                 _listen_acceptor.reset (
 189                         new tcp::acceptor (_listen_io_service, tcp::endpoint(tcp::v4(), is_batch_converter ? BATCH_SERVER_PRESENCE_PORT : MAIN_SERVER_PRESENCE_PORT))
 190                         );
 191         } catch (...) {
 192                 boost::throw_exception(NetworkError(variant::insert_dcpomatic(_("Could not listen for remote encode servers.  Perhaps another instance of %1 is running."))));
 193         }
 194
 195         start_accept ();
 196         _listen_io_service.run ();
 197 }
 198 catch (...)
 199 {
 200         store_current ();
 201 }
 202
 203
 204 void
 205 EncodeServerFinder::start_accept ()
 206 {
 207         _accept_socket = make_shared<Socket>();
 208
 209         _listen_acceptor->async_accept (
 210                 _accept_socket->socket(),
 211                 boost::bind(&EncodeServerFinder::handle_accept, this, boost::asio::placeholders::error)
 212                 );
 213 }
 214
 215
 216 void
 217 EncodeServerFinder::handle_accept (boost::system::error_code ec)
 218 {
 219         if (ec) {
 220                 start_accept ();
 221                 return;
 222         }
 223
 224         string server_available;
 225
 226         try {
 227                 uint32_t length;
 228                 _accept_socket->read (reinterpret_cast<uint8_t*>(&length), sizeof(uint32_t));
 229                 length = ntohl (length);
 230
 231                 if (length > 65536) {
 232                         start_accept();
 233                         return;
 234                 }
 235
 236                 scoped_array<char> buffer(new char[length]);
 237                 _accept_socket->read (reinterpret_cast<uint8_t*>(buffer.get()), length);
 238                 server_available = buffer.get();
 239         } catch (NetworkError&) {
 240                 /* Maybe the server went away; let's just try again */
 241                 start_accept();
 242                 return;
 243         }
 244
 245         auto xml = make_shared<cxml::Document>("ServerAvailable");
 246         xml->read_string(server_available);
 247
 248         auto const ip = _accept_socket->socket().remote_endpoint().address().to_string();
 249         bool changed = false;
 250         {
 251                 boost::mutex::scoped_lock lm (_servers_mutex);
 252                 auto i = _servers.begin();
 253                 while (i != _servers.end() && i->host_name() != ip) {
 254                         ++i;
 255                 }
 256
 257                 if (i != _servers.end()) {
 258                         i->set_seen();
 259                 } else {
 260                         EncodeServerDescription sd (ip, xml->number_child<int>("Threads"), xml->optional_number_child<int>("Version").get_value_or(0));
 261                         _servers.push_back (sd);
 262                         changed = true;
 263                 }
 264         }
 265
 266         if (changed) {
 267                 emit (boost::bind(boost::ref (ServersListChanged)));
 268         }
 269
 270         start_accept ();
 271 }
 272
 273
 274 EncodeServerFinder*
 275 EncodeServerFinder::instance ()
 276 {
 277         if (!_instance) {
 278                 _instance = new EncodeServerFinder ();
 279                 _instance->start ();
 280         }
 281
 282         return _instance;
 283 }
 284
 285
 286 void
 287 EncodeServerFinder::drop ()
 288 {
 289         delete _instance;
 290         _instance = nullptr;
 291 }
 292
 293
 294 list<EncodeServerDescription>
 295 EncodeServerFinder::servers () const
 296 {
 297         boost::mutex::scoped_lock lm (_servers_mutex);
 298         return _servers;
 299 }
 300
 301
 302 void
 303 EncodeServerFinder::config_changed (Config::Property what)
 304 {
 305         if (what == Config::USE_ANY_SERVERS || what == Config::SERVERS) {
 306                 {
 307                         boost::mutex::scoped_lock lm (_servers_mutex);
 308                         _servers.clear ();
 309                 }
 310                 ServersListChanged ();
 311                 _search_condition.notify_all ();
 312         }
 313 }