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 <time.h>
  13 #include <iostream>
  14 #include <limits>
  15 #include <new>
  16 #include <stdlib.h>
  17 #include <assert.h>
  18
  19 #include <avahi-client/client.h>
  20 #include <avahi-client/publish.h>
  21
  22 #include <avahi-common/alternative.h>
  23 #include <avahi-common/malloc.h>
  24 #include <avahi-common/error.h>
  25 #include <avahi-common/timeval.h>
  26 #include <avahi-common/thread-watch.h>
  27 #include <comphelper/random.hxx>
  28
  29 #if ENABLE_DBUS
  30 #include <dbus/dbus.h>
  31 #endif
  32
  33 #include <sal/log.hxx>
  34
  35 #include "AvahiNetworkService.hxx"
  36 #include "ZeroconfService.hxx"
  37
  38 using namespace sd;
  39
  40 static AvahiClient *client = nullptr;
  41 static AvahiThreadedPoll *threaded_poll = nullptr;
  42 static AvahiEntryGroup *group = nullptr;
  43 static AvahiNetworkService *avahiService = nullptr;
  44
  45 static bool create_services(AvahiClient *c);
  46
  47 static void entry_group_callback(AvahiEntryGroup *g, AvahiEntryGroupState state, AVAHI_GCC_UNUSED void *userdata) {
  48     assert(g == group || group == nullptr);
  49     group = g;
  50
  51     /* Called whenever the entry group state changes */
  52
  53     switch (state) {
  54         case AVAHI_ENTRY_GROUP_ESTABLISHED :
  55             /* The entry group has been established successfully */
  56             SAL_INFO( "sdremote.wifi", "Service '" << avahiService->getName() << "' successfully established." );
  57             break;
  58
  59         case AVAHI_ENTRY_GROUP_COLLISION : {
  60             char *n;
  61
  62             /* A service name collision with a remote service
  63              * happened. Let's pick a new name */
  64             n = avahi_alternative_service_name(avahiService->getName().c_str());
  65             avahiService->setName(n);
  66
  67             SAL_INFO( "sdremote.wifi", "Service name collision, renaming service to '" << avahiService->getName() << "'");
  68
  69             /* And recreate the services */
  70             create_services(avahi_entry_group_get_client(g));
  71             break;
  72         }
  73
  74         case AVAHI_ENTRY_GROUP_FAILURE :
  75
  76             SAL_WARN("sdremote.wifi", "Entry group failure: " << avahi_strerror(avahi_client_errno(avahi_entry_group_get_client(g))));
  77
  78             /* Some kind of failure happened while we were registering our services */
  79             avahi_threaded_poll_quit(threaded_poll);
  80             break;
  81
  82         case AVAHI_ENTRY_GROUP_UNCOMMITED:
  83         case AVAHI_ENTRY_GROUP_REGISTERING:
  84             ;
  85     }
  86 }
  87
  88 static bool create_services(AvahiClient *c) {
  89     assert(c);
  90
  91     /* If this is the first time we're called, let's create a new
  92      * entry group if necessary */
  93     if(!client)
  94         return false;
  95
  96     if (!group)
  97         if (!(group = avahi_entry_group_new(c, entry_group_callback, nullptr))) {
  98             SAL_WARN("sdremote.wifi", "avahi_entry_group_new() failed: " << avahi_strerror(avahi_client_errno(c)));
  99             avahiService->clear();
 100             return false;
 101         }
 102
 103     /* If the group is empty (either because it was just created, or
 104      * because it was reset previously, add our entries.  */
 105
 106     if (avahi_entry_group_is_empty(group)) {
 107         SAL_INFO("sdremote.wifi", "Adding service '" << avahiService->getName() << "'");
 108         char r[128];
 109         int nRandom = comphelper::rng::uniform_int_distribution(0, std::numeric_limits<int>::max());
 110         snprintf(r, sizeof(r), "random=%i", nRandom);
 111         int ret = avahi_entry_group_add_service(
 112             group, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, static_cast<AvahiPublishFlags>(0),
 113             avahiService->getName().c_str(), kREG_TYPE, nullptr, nullptr, 1599, "local", r, nullptr
 114         );
 115         if (ret < 0) {
 116
 117             if (ret == AVAHI_ERR_COLLISION){
 118                 /* A service name collision with a local service happened. Let's
 119                  * pick a new name */
 120                 char *n = avahi_alternative_service_name(avahiService->getName().c_str());
 121                 avahiService->setName(n);
 122
 123                 SAL_WARN("sdremote.wifi", "Service name collision, renaming service to '" << avahiService->getName() << "'");
 124
 125                 avahi_entry_group_reset(group);
 126
 127                 return create_services(c);
 128             }
 129
 130             SAL_WARN("sdremote.wifi", "Failed to add _impressremote._tcp service: " << avahi_strerror(ret));
 131             avahiService->clear();
 132             return false;
 133         }
 134
 135         /* Tell the server to register the service */
 136         if ((ret = avahi_entry_group_commit(group)) < 0) {
 137             SAL_WARN("sdremote.wifi", "Failed to commit entry group: " << avahi_strerror(ret));
 138             avahiService->clear();
 139             return false;
 140         }
 141     }
 142
 143     return true; //Services we're already created
 144 }
 145
 146 static void client_callback(AvahiClient *c, AvahiClientState state, AVAHI_GCC_UNUSED void * userdata) {
 147     assert(c);
 148
 149     /* Called whenever the client or server state changes */
 150
 151     switch (state) {
 152         case AVAHI_CLIENT_S_RUNNING:
 153             create_services(c);
 154             break;
 155         case AVAHI_CLIENT_FAILURE:
 156             SAL_WARN("sdremote.wifi", "Client failure: " << avahi_strerror(avahi_client_errno(c)));
 157             avahiService->clear();
 158             break;
 159         case AVAHI_CLIENT_S_COLLISION:
 160         case AVAHI_CLIENT_S_REGISTERING:
 161             if (group)
 162                 avahi_entry_group_reset(group);
 163             break;
 164         case AVAHI_CLIENT_CONNECTING:
 165             ;
 166     }
 167 }
 168
 169 void AvahiNetworkService::setup() {
 170 #if ENABLE_DBUS
 171     // Sure, without ENABLE_DBUS it probably makes no sense to try to use this Avahi stuff either,
 172     // but this is just a stop-gap measure to get this to even compile for now with the probably
 173     // pointless combination of configurable options --enable-avahi --enable-dbus --disable-gui.
 174
 175     // Avahi internally uses D-Bus, which requires the following in order to be
 176     // thread-safe (and we potentially access D-Bus from different threads in
 177     // different places of the code base):
 178     if (!dbus_threads_init_default()) {
 179         throw std::bad_alloc();
 180     }
 181 #endif
 182
 183     int error = 0;
 184     avahiService = this;
 185     if (!(threaded_poll = avahi_threaded_poll_new())) {
 186        SAL_WARN("sdremote.wifi", "avahi_threaded_poll_new '" << avahiService->getName() << "' failed");
 187        return;
 188     }
 189
 190     if (!(client = avahi_client_new(avahi_threaded_poll_get(threaded_poll), static_cast<AvahiClientFlags>(0), client_callback, nullptr, &error))) {
 191        SAL_WARN("sdremote.wifi", "avahi_client_new failed");
 192        return;
 193     }
 194
 195     if(!create_services(client))
 196         return;
 197
 198     /* Finally, start the event loop thread */
 199     if (avahi_threaded_poll_start(threaded_poll) < 0) {
 200        SAL_WARN("sdremote.wifi", "avahi_threaded_poll_start failed");
 201        return;
 202     }
 203 }
 204
 205 void AvahiNetworkService::clear() {
 206     /* Call this when the app shuts down */
 207         if(threaded_poll)
 208             avahi_threaded_poll_stop(threaded_poll);
 209         if(client)
 210             avahi_client_free(client);
 211         if(threaded_poll)
 212             avahi_threaded_poll_free(threaded_poll);
 213 }