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         _good_servers.clear ();
 103         _bad_servers.clear ();
 104 }
 105
 106 static bool
 107 remove_missing (list<EncodeServerDescription>& servers, int since)
 108 {
 109         bool removed = false;
 110         list<EncodeServerDescription>::iterator i = servers.begin();
 111         while (i != servers.end()) {
 112                 if (i->last_seen_seconds() > since) {
 113                         list<EncodeServerDescription>::iterator j = i;
 114                         ++j;
 115                         servers.erase (i);
 116                         i = j;
 117                         removed = true;
 118                 } else {
 119                         ++i;
 120                 }
 121         }
 122         return removed;
 123 }
 124
 125 void
 126 EncodeServerFinder::search_thread ()
 127 try
 128 {
 129         boost::system::error_code error;
 130         boost::asio::io_service io_service;
 131         boost::asio::ip::udp::socket socket (io_service);
 132         socket.open (boost::asio::ip::udp::v4(), error);
 133         if (error) {
 134                 throw NetworkError ("failed to set up broadcast socket");
 135         }
 136
 137         socket.set_option (boost::asio::ip::udp::socket::reuse_address (true));
 138         socket.set_option (boost::asio::socket_base::broadcast (true));
 139
 140         string const data = DCPOMATIC_HELLO;
 141         int const interval = 10;
 142
 143         while (!_stop) {
 144                 if (Config::instance()->use_any_servers ()) {
 145                         /* Broadcast to look for servers */
 146                         try {
 147                                 boost::asio::ip::udp::endpoint end_point (boost::asio::ip::address_v4::broadcast(), HELLO_PORT);
 148                                 socket.send_to (boost::asio::buffer (data.c_str(), data.size() + 1), end_point);
 149                         } catch (...) {
 150
 151                         }
 152                 }
 153
 154                 /* Query our `definite' servers (if there are any) */
 155                 vector<string> servers = Config::instance()->servers ();
 156                 for (vector<string>::const_iterator i = servers.begin(); i != servers.end(); ++i) {
 157                         if (server_found (*i)) {
 158                                 /* Don't bother asking a server that we already know about */
 159                                 continue;
 160                         }
 161                         try {
 162                                 boost::asio::ip::udp::resolver resolver (io_service);
 163                                 boost::asio::ip::udp::resolver::query query (*i, raw_convert<string> (HELLO_PORT));
 164                                 boost::asio::ip::udp::endpoint end_point (*resolver.resolve (query));
 165                                 socket.send_to (boost::asio::buffer (data.c_str(), data.size() + 1), end_point);
 166                         } catch (...) {
 167
 168                         }
 169                 }
 170
 171                 /* Discard servers that we haven't seen for a while */
 172                 {
 173                         boost::mutex::scoped_lock lm (_servers_mutex);
 174                         bool g = remove_missing(_good_servers, 2 * interval);
 175                         bool b = remove_missing(_bad_servers, 2 * interval);
 176                         if (g || b) {
 177                                 emit (boost::bind (boost::ref (ServersListChanged)));
 178                         }
 179                 }
 180
 181                 boost::mutex::scoped_lock lm (_search_condition_mutex);
 182                 _search_condition.timed_wait (lm, boost::get_system_time() + boost::posix_time::seconds (interval));
 183         }
 184 }
 185 catch (...)
 186 {
 187         store_current ();
 188 }
 189
 190 void
 191 EncodeServerFinder::listen_thread ()
 192 try {
 193         using namespace boost::asio::ip;
 194
 195         try {
 196                 _listen_acceptor.reset (
 197                         new tcp::acceptor (_listen_io_service, tcp::endpoint (tcp::v4(), is_batch_converter ? BATCH_SERVER_PRESENCE_PORT : MAIN_SERVER_PRESENCE_PORT))
 198                         );
 199         } catch (...) {
 200                 boost::throw_exception (NetworkError (_("Could not listen for remote encode servers.  Perhaps another instance of DCP-o-matic is running.")));
 201         }
 202
 203         start_accept ();
 204         _listen_io_service.run ();
 205 }
 206 catch (...)
 207 {
 208         store_current ();
 209 }
 210
 211 void
 212 EncodeServerFinder::start_accept ()
 213 {
 214         shared_ptr<Socket> socket (new Socket ());
 215         _listen_acceptor->async_accept (
 216                 socket->socket(),
 217                 boost::bind (&EncodeServerFinder::handle_accept, this, boost::asio::placeholders::error, socket)
 218                 );
 219 }
 220
 221 void
 222 EncodeServerFinder::handle_accept (boost::system::error_code ec, shared_ptr<Socket> socket)
 223 {
 224         if (ec) {
 225                 start_accept ();
 226                 return;
 227         }
 228
 229         uint32_t length;
 230         socket->read (reinterpret_cast<uint8_t*> (&length), sizeof (uint32_t));
 231         length = ntohl (length);
 232
 233         scoped_array<char> buffer (new char[length]);
 234         socket->read (reinterpret_cast<uint8_t*> (buffer.get()), length);
 235
 236         string s (buffer.get());
 237         shared_ptr<cxml::Document> xml (new cxml::Document ("ServerAvailable"));
 238         xml->read_string (s);
 239
 240         string const ip = socket->socket().remote_endpoint().address().to_string ();
 241         optional<list<EncodeServerDescription>::iterator> found = server_found (ip);
 242         if (found) {
 243                 (*found)->set_seen ();
 244         } else {
 245                 EncodeServerDescription sd (ip, xml->number_child<int>("Threads"), xml->optional_number_child<int>("Version").get_value_or(0));
 246                 if (sd.link_version() == SERVER_LINK_VERSION) {
 247                         boost::mutex::scoped_lock lm (_servers_mutex);
 248                         _good_servers.push_back (sd);
 249                 } else {
 250                         boost::mutex::scoped_lock lm (_servers_mutex);
 251                         _bad_servers.push_back (sd);
 252                 }
 253                 emit (boost::bind (boost::ref (ServersListChanged)));
 254         }
 255
 256         start_accept ();
 257 }
 258
 259 optional<list<EncodeServerDescription>::iterator>
 260 EncodeServerFinder::server_found (string ip)
 261 {
 262         boost::mutex::scoped_lock lm (_servers_mutex);
 263         list<EncodeServerDescription>::iterator i = _good_servers.begin();
 264         while (i != _good_servers.end() && i->host_name() != ip) {
 265                 ++i;
 266         }
 267
 268         if (i != _good_servers.end()) {
 269                 return i;
 270         }
 271
 272         i = _bad_servers.begin();
 273         while (i != _bad_servers.end() && i->host_name() != ip) {
 274                 ++i;
 275         }
 276
 277         if (i != _bad_servers.end()) {
 278                 return i;
 279         }
 280
 281         return optional<list<EncodeServerDescription>::iterator>();
 282 }
 283
 284 EncodeServerFinder*
 285 EncodeServerFinder::instance ()
 286 {
 287         if (!_instance) {
 288                 _instance = new EncodeServerFinder ();
 289                 _instance->start ();
 290         }
 291
 292         return _instance;
 293 }
 294
 295 void
 296 EncodeServerFinder::drop ()
 297 {
 298         delete _instance;
 299         _instance = 0;
 300 }
 301
 302 list<EncodeServerDescription>
 303 EncodeServerFinder::good_servers () const
 304 {
 305         boost::mutex::scoped_lock lm (_servers_mutex);
 306         return _good_servers;
 307 }
 308
 309 list<EncodeServerDescription>
 310 EncodeServerFinder::bad_servers () const
 311 {
 312         boost::mutex::scoped_lock lm (_servers_mutex);
 313         return _bad_servers;
 314 }
 315
 316 void
 317 EncodeServerFinder::config_changed (Config::Property what)
 318 {
 319         if (what == Config::USE_ANY_SERVERS || what == Config::SERVERS) {
 320                 {
 321                         boost::mutex::scoped_lock lm (_servers_mutex);
 322                         _good_servers.clear ();
 323                         _bad_servers.clear ();
 324                 }
 325                 ServersListChanged ();
 326                 _search_condition.notify_all ();
 327         }
 328 }