sd/source/ui/remotecontrol/AvahiNetworkService.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  */
   9
  10 #include <config_dbus.h>
  11
  12 #include <iostream>
  13 #include <limits>
  14 #include <new>
  15 #include <assert.h>
  16
  17 #include <avahi-client/client.h>
  18 #include <avahi-client/publish.h>
  19
  20 #include <avahi-common/alternative.h>
  21 #include <avahi-common/error.h>
  22 #include <avahi-common/thread-watch.h>
  23 #include <comphelper/random.hxx>
  24
  25 #if ENABLE_DBUS
  26 #include <dbus/dbus.h>
  27 #endif
  28
  29 #include <sal/log.hxx>
  30
  31 #include "AvahiNetworkService.hxx"
  32 #include "ZeroconfService.hxx"
  33
  34 using namespace sd;
  35
  36 static AvahiClient *client = nullptr;
  37 static AvahiThreadedPoll *threaded_poll = nullptr;
  38 static AvahiEntryGroup *group = nullptr;
  39 static AvahiNetworkService *avahiService = nullptr;
  40
  41 static bool create_services(AvahiClient *c);
  42
  43 static void entry_group_callback(AvahiEntryGroup *g, AvahiEntryGroupState state, AVAHI_GCC_UNUSED void *userdata) {
  44     assert(g == group || group == nullptr);
  45     group = g;
  46
  47     /* Called whenever the entry group state changes */
  48
  49     switch (state) {
  50         case AVAHI_ENTRY_GROUP_ESTABLISHED :
  51             /* The entry group has been established successfully */
  52             SAL_INFO( "sdremote.wifi", "Service '" << avahiService->getName() << "' successfully established." );
  53             break;
  54
  55         case AVAHI_ENTRY_GROUP_COLLISION : {
  56             char *n;
  57
  58             /* A service name collision with a remote service
  59              * happened. Let's pick a new name */
  60             n = avahi_alternative_service_name(avahiService->getName().c_str());
  61             avahiService->setName(n);
  62
  63             SAL_INFO( "sdremote.wifi", "Service name collision, renaming service to '" << avahiService->getName() << "'");
  64
  65             /* And recreate the services */
  66             create_services(avahi_entry_group_get_client(g));
  67             break;
  68         }
  69
  70         case AVAHI_ENTRY_GROUP_FAILURE :
  71
  72             SAL_WARN("sdremote.wifi", "Entry group failure: " << avahi_strerror(avahi_client_errno(avahi_entry_group_get_client(g))));
  73
  74             /* Some kind of failure happened while we were registering our services */
  75             avahi_threaded_poll_quit(threaded_poll);
  76             break;
  77
  78         case AVAHI_ENTRY_GROUP_UNCOMMITED:
  79         case AVAHI_ENTRY_GROUP_REGISTERING:
  80             ;
  81     }
  82 }
  83
  84 static bool create_services(AvahiClient *c) {
  85     assert(c);
  86
  87     /* If this is the first time we're called, let's create a new
  88      * entry group if necessary */
  89     if(!client)
  90         return false;
  91
  92     if (!group)
  93         if (!(group = avahi_entry_group_new(c, entry_group_callback, nullptr))) {
  94             SAL_WARN("sdremote.wifi", "avahi_entry_group_new() failed: " << avahi_strerror(avahi_client_errno(c)));
  95             avahiService->clear();
  96             return false;
  97         }
  98
  99     /* If the group is empty (either because it was just created, or
 100      * because it was reset previously, add our entries.  */
 101
 102     if (avahi_entry_group_is_empty(group)) {
 103         SAL_INFO("sdremote.wifi", "Adding service '" << avahiService->getName() << "'");
 104         char r[128];
 105         int nRandom = comphelper::rng::uniform_int_distribution(0, std::numeric_limits<int>::max());
 106         snprintf(r, sizeof(r), "random=%i", nRandom);
 107         int ret = avahi_entry_group_add_service(
 108             group, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, static_cast<AvahiPublishFlags>(0),
 109             avahiService->getName().c_str(), kREG_TYPE, nullptr, nullptr, 1599, "local", r, nullptr
 110         );
 111         if (ret < 0) {
 112
 113             if (ret == AVAHI_ERR_COLLISION){
 114                 /* A service name collision with a local service happened. Let's
 115                  * pick a new name */
 116                 char *n = avahi_alternative_service_name(avahiService->getName().c_str());
 117                 avahiService->setName(n);
 118
 119                 SAL_WARN("sdremote.wifi", "Service name collision, renaming service to '" << avahiService->getName() << "'");
 120
 121                 avahi_entry_group_reset(group);
 122
 123                 return create_services(c);
 124             }
 125
 126             SAL_WARN("sdremote.wifi", "Failed to add _impressremote._tcp service: " << avahi_strerror(ret));
 127             avahiService->clear();
 128             return false;
 129         }
 130
 131         /* Tell the server to register the service */
 132         if ((ret = avahi_entry_group_commit(group)) < 0) {
 133             SAL_WARN("sdremote.wifi", "Failed to commit entry group: " << avahi_strerror(ret));
 134             avahiService->clear();
 135             return false;
 136         }
 137     }
 138
 139     return true; //Services we're already created
 140 }
 141
 142 static void client_callback(AvahiClient *c, AvahiClientState state, AVAHI_GCC_UNUSED void * userdata) {
 143     assert(c);
 144
 145     /* Called whenever the client or server state changes */
 146
 147     switch (state) {
 148         case AVAHI_CLIENT_S_RUNNING:
 149             create_services(c);
 150             break;
 151         case AVAHI_CLIENT_FAILURE:
 152             SAL_WARN("sdremote.wifi", "Client failure: " << avahi_strerror(avahi_client_errno(c)));
 153             avahiService->clear();
 154             break;
 155         case AVAHI_CLIENT_S_COLLISION:
 156         case AVAHI_CLIENT_S_REGISTERING:
 157             if (group)
 158                 avahi_entry_group_reset(group);
 159             break;
 160         case AVAHI_CLIENT_CONNECTING:
 161             ;
 162     }
 163 }
 164
 165 void AvahiNetworkService::setup() {
 166 #if ENABLE_DBUS
 167     // Sure, without ENABLE_DBUS it probably makes no sense to try to use this Avahi stuff either,
 168     // but this is just a stop-gap measure to get this to even compile for now with the probably
 169     // pointless combination of configurable options --enable-avahi --enable-dbus --disable-gui.
 170
 171     // Avahi internally uses D-Bus, which requires the following in order to be
 172     // thread-safe (and we potentially access D-Bus from different threads in
 173     // different places of the code base):
 174     if (!dbus_threads_init_default()) {
 175         throw std::bad_alloc();
 176     }
 177 #endif
 178
 179     int error = 0;
 180     avahiService = this;
 181     if (!(threaded_poll = avahi_threaded_poll_new())) {
 182        SAL_WARN("sdremote.wifi", "avahi_threaded_poll_new '" << avahiService->getName() << "' failed");
 183        return;
 184     }
 185
 186     if (!(client = avahi_client_new(avahi_threaded_poll_get(threaded_poll), static_cast<AvahiClientFlags>(0), client_callback, nullptr, &error))) {
 187        SAL_WARN("sdremote.wifi", "avahi_client_new failed");
 188        return;
 189     }
 190
 191     if(!create_services(client))
 192         return;
 193
 194     /* Finally, start the event loop thread */
 195     if (avahi_threaded_poll_start(threaded_poll) < 0) {
 196        SAL_WARN("sdremote.wifi", "avahi_threaded_poll_start failed");
 197        return;
 198     }
 199 }
 200
 201 void AvahiNetworkService::clear() {
 202     /* Call this when the app shuts down */
 203         if(threaded_poll)
 204             avahi_threaded_poll_stop(threaded_poll);
 205         if(client)
 206             avahi_client_free(client);
 207         if(threaded_poll)
 208             avahi_threaded_poll_free(threaded_poll);
 209 }