Added zeroconf service publishing using avahi

git-svn-id: https://svn.musicpd.org/mpd/trunk@5238 09075e82-0dd4-0310-85a5-a0d7c8717e4f

1 files changed, 493 insertions, 0 deletions

diff --git a/src/zeroconf.c b/src/zeroconf.c
new file mode 100644
index 00000000..0fa8d739
--- /dev/null
+++ b/src/zeroconf.c
@@ -0,0 +1,493 @@
+/* the Music Player Daemon (MPD)
+ * (c)2003-2006 by Warren Dukes (warren.dukes@gmail.com)
+ * This project's homepage is: http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <stdlib.h>
+#include <assert.h>
+#include <string.h>
+
+#include "zeroconf.h"
+#include "conf.h"
+#include "log.h"
+#include "listen.h"
+#include "ioops.h"
+
+/* The dns-sd service type qualifier to publish */
+#define SERVICE_TYPE		"_mpd._tcp"
+
+/* The default service name to publish 
+ * (overridden by 'zeroconf_name' config parameter)
+ */
+#define SERVICE_NAME		"Music Player"
+
+/* Here is the implementation for Avahi (http://avahi.org) Zeroconf support */
+#if HAVE_AVAHI
+
+#include <avahi-client/client.h>
+#include <avahi-client/publish.h>
+
+#include <avahi-common/alternative.h>
+#include <avahi-common/domain.h>
+#include <avahi-common/malloc.h>
+#include <avahi-common/error.h>
+
+/* Static avahi data */
+static AvahiEntryGroup *avahiGroup = NULL;
+static char *avahiName = NULL;
+static AvahiClient* avahiClient = NULL;
+static AvahiPoll avahiPoll;
+static int avahiRunning = 0;
+
+static int avahiFdset( fd_set* rfds, fd_set* wfds, fd_set* efds );
+static int avahiFdconsume( int fdCount, fd_set* rfds, fd_set* wfds, fd_set* efds );
+static struct ioOps avahiIo = {
+	.fdset = avahiFdset,
+	.consume = avahiFdconsume,
+};
+
+/* Forward Declaration */
+static void avahiRegisterService(AvahiClient *c);
+
+struct AvahiWatch {
+	struct AvahiWatch* prev;
+	struct AvahiWatch* next;
+	int fd;
+	AvahiWatchEvent requestedEvent;
+	AvahiWatchEvent observedEvent;
+	AvahiWatchCallback callback;
+	void* userdata;
+};
+
+struct AvahiTimeout {
+	struct AvahiTimeout* prev;
+	struct AvahiTimeout* next;
+	struct timeval expiry;
+	int enabled;
+	AvahiTimeoutCallback callback;
+	void* userdata;
+};
+
+static AvahiWatch* avahiWatchList;
+static AvahiTimeout* avahiTimeoutList;
+
+static AvahiWatch* avahiWatchNew( const AvahiPoll *api, int fd, AvahiWatchEvent event, AvahiWatchCallback callback, void *userdata )
+{
+	struct AvahiWatch* newWatch = malloc( sizeof(struct AvahiWatch) );
+
+	newWatch->fd = fd;
+	newWatch->requestedEvent = event;
+	newWatch->observedEvent = 0;
+	newWatch->callback = callback;
+	newWatch->userdata = userdata;
+
+	/* Insert at front of list */
+	newWatch->next = avahiWatchList;
+	avahiWatchList = newWatch;
+	newWatch->prev = NULL;
+	if( newWatch->next )
+		newWatch->next->prev = newWatch;
+
+	return newWatch;
+}
+
+static void avahiWatchUpdate( AvahiWatch *w, AvahiWatchEvent event )
+{
+	assert( w != NULL );
+	w->requestedEvent = event;
+}
+
+static AvahiWatchEvent avahiWatchGetEvents( AvahiWatch *w )
+{
+	assert( w != NULL );
+	return w->observedEvent;
+}
+
+static void avahiWatchFree( AvahiWatch *w )
+{
+	assert( w != NULL );
+
+	if( avahiWatchList == w )
+		avahiWatchList = w->next;
+	else if( w->prev != NULL )
+		w->prev->next = w->next;
+
+	free( w );
+}
+
+static void avahiCheckExpiry( AvahiTimeout *t )
+{
+	assert( t != NULL );
+	if( t->enabled ) {
+		struct timeval now;
+		gettimeofday( &now, NULL );
+		if( timercmp( &now, &(t->expiry), > ) ) {
+			t->enabled = 0;
+			t->callback( t, t->userdata );
+		}
+	}
+}
+
+static void avahiTimeoutUpdate( AvahiTimeout *t, const struct timeval *tv )
+{
+	assert( t != NULL );
+	if( tv ) {
+		t->enabled = 1;
+		t->expiry.tv_sec = tv->tv_sec;
+		t->expiry.tv_usec = tv->tv_usec;
+	} else {
+		t->enabled = 0;
+	}
+}
+
+static void avahiTimeoutFree( AvahiTimeout *t )
+{
+	assert( t != NULL );
+
+	if( avahiTimeoutList == t )
+		avahiTimeoutList = t->next;
+	else if( t->prev != NULL )
+		t->prev->next = t->next;
+
+	free( t );
+}
+
+static AvahiTimeout* avahiTimeoutNew( const AvahiPoll *api, const struct timeval *tv, AvahiTimeoutCallback callback, void *userdata )
+{
+	struct AvahiTimeout* newTimeout = malloc( sizeof(struct AvahiTimeout) );
+
+	newTimeout->callback = callback;
+	newTimeout->userdata = userdata;
+
+	avahiTimeoutUpdate( newTimeout, tv );
+
+	/* Insert at front of list */
+	newTimeout->next = avahiTimeoutList;
+	avahiTimeoutList = newTimeout;
+	newTimeout->prev = NULL;
+	if( newTimeout->next )
+		newTimeout->next->prev = newTimeout;
+	
+	return newTimeout;
+}
+
+/* Callback when the EntryGroup changes state */
+static void avahiGroupCallback(
+		AvahiEntryGroup *g,
+		AvahiEntryGroupState state,
+		void *userdata)
+{
+	assert(g);
+
+	DEBUG( "Avahi: Service group changed to state %d\n", state );
+
+	switch (state) {
+		case AVAHI_ENTRY_GROUP_ESTABLISHED :
+			/* The entry group has been established successfully */
+			LOG( "Avahi: Service '%s' successfully established.\n", avahiName );
+			break;
+
+		case AVAHI_ENTRY_GROUP_COLLISION : {
+			char *n;
+			
+			/* A service name collision happened. Let's pick a new name */
+			n = avahi_alternative_service_name(avahiName);
+			avahi_free(avahiName);
+			avahiName = n;
+			
+			LOG( "Avahi: Service name collision, renaming service to '%s'\n", avahiName );
+
+			/* And recreate the services */
+			avahiRegisterService(avahi_entry_group_get_client(g));
+			break;
+		}
+
+		case AVAHI_ENTRY_GROUP_FAILURE :
+			ERROR( "Avahi: Entry group failure: %s\n",
+					avahi_strerror(avahi_client_errno(avahi_entry_group_get_client(g))) );
+			/* Some kind of failure happened while we were registering our services */
+			avahiRunning = 0;
+			break;
+
+		case AVAHI_ENTRY_GROUP_UNCOMMITED:
+			DEBUG( "Avahi: Service group is UNCOMMITED\n" );
+			break;
+		case AVAHI_ENTRY_GROUP_REGISTERING:
+			DEBUG( "Avahi: Service group is REGISTERING\n" );
+			;
+	}
+}
+
+/* Registers a new service with avahi */
+static void avahiRegisterService(AvahiClient *c)
+{
+	int ret;
+	assert(c);
+	DEBUG( "Avahi: Registering service %s/%s\n", SERVICE_TYPE, avahiName );
+
+	/* If this is the first time we're called, let's create a new entry group */
+	if (!avahiGroup) {
+		avahiGroup = avahi_entry_group_new(c, avahiGroupCallback, NULL);
+		if( !avahiGroup ) {
+			ERROR( "Avahi: Failed to create avahi EntryGroup: %s\n", avahi_strerror(avahi_client_errno(c)) );
+			goto fail;
+		}
+	}
+
+	/* Add the service */
+	/* TODO: This currently binds to ALL interfaces.
+	 *       We could maybe add a service per actual bound interface, if that's better. */
+	ret = avahi_entry_group_add_service(avahiGroup,
+					AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, 0,
+					avahiName, SERVICE_TYPE,
+					NULL, NULL,
+					getBoundPort(),
+					NULL);
+	if( ret < 0 ) {
+		ERROR( "Avahi: Failed to add service %s: %s\n", SERVICE_TYPE, avahi_strerror(ret) );
+		goto fail;
+	}
+
+	/* Tell the server to register the service group */
+	ret = avahi_entry_group_commit(avahiGroup);
+	if( ret < 0 ) {
+		ERROR( "Avahi: Failed to commit service group: %s\n", avahi_strerror(ret) );
+		goto fail;
+	}
+	return;
+
+fail:
+	avahiRunning = 0;
+}
+
+/* Callback when avahi changes state */
+static void avahiClientCallback(AvahiClient *c, AvahiClientState state, void *userdata)
+{
+	assert(c);
+
+	/* Called whenever the client or server state changes */
+	DEBUG( "Avahi: Client changed to state %d\n", state );
+
+	switch (state) {
+		case AVAHI_CLIENT_S_RUNNING:
+			DEBUG( "Avahi: Client is RUNNING\n" );
+		
+			/* The server has startup successfully and registered its host
+			 * name on the network, so it's time to create our services */
+			if (!avahiGroup)
+				avahiRegisterService(c);
+			break;
+
+		case AVAHI_CLIENT_FAILURE:
+			{
+				int reason = avahi_client_errno(c);
+				if( reason == AVAHI_ERR_DISCONNECTED ) {
+					LOG( "Avahi: Client Disconnected, will reconnect shortly\n");
+					avahi_entry_group_free( avahiGroup );
+					avahiGroup = NULL;
+					avahi_client_free( avahiClient );
+					avahiClient = NULL;
+					avahiClient = avahi_client_new( &avahiPoll, AVAHI_CLIENT_NO_FAIL,
+						avahiClientCallback, NULL, &reason );
+					if( !avahiClient ) {
+						ERROR( "Avahi: Could not reconnect: %s\n", avahi_strerror(reason) );
+						avahiRunning = 0;
+					}
+				} else {
+					ERROR( "Avahi: Client failure: %s (terminal)\n", avahi_strerror(reason));
+					avahiRunning = 0;
+				}
+			}
+			break;
+
+		case AVAHI_CLIENT_S_COLLISION:
+			DEBUG( "Avahi: Client is COLLISION\n" );
+			/* Let's drop our registered services. When the server is back
+			 * in AVAHI_SERVER_RUNNING state we will register them
+			 * again with the new host name. */
+			if (avahiGroup) {
+				DEBUG( "Avahi: Resetting group\n" );
+				avahi_entry_group_reset(avahiGroup);
+			}
+			
+		case AVAHI_CLIENT_S_REGISTERING:
+			DEBUG( "Avahi: Client is REGISTERING\n" );
+			/* The server records are now being established. This
+			 * might be caused by a host name change. We need to wait
+			 * for our own records to register until the host name is
+			 * properly esatblished. */
+			
+			if (avahiGroup) {
+				DEBUG( "Avahi: Resetting group\n" );
+				avahi_entry_group_reset(avahiGroup);
+			}
+			
+			break;
+
+		case AVAHI_CLIENT_CONNECTING:
+			DEBUG( "Avahi: Client is CONNECTING\n" );
+			;
+	}
+}
+
+static int avahiFdset( fd_set* rfds, fd_set* wfds, fd_set* efds )
+{
+	AvahiWatch* w;
+	int maxfd = -1;
+	if( !avahiRunning )
+		return maxfd;
+	for( w = avahiWatchList; w != NULL; w = w->next ) {
+		if( w->requestedEvent & AVAHI_WATCH_IN ) {
+			FD_SET( w->fd, rfds );
+		} 
+		if( w->requestedEvent & AVAHI_WATCH_OUT ) {
+			FD_SET( w->fd, wfds );
+		}
+		if( w->requestedEvent & AVAHI_WATCH_ERR ) {
+			FD_SET( w->fd, efds );
+		}
+		if( w->requestedEvent & AVAHI_WATCH_HUP ) {
+			ERROR( "Avahi: No support for HUP events! (ignoring)\n" );
+		}
+
+		if( w->fd > maxfd )
+			maxfd = w->fd;
+	}
+	return maxfd; 
+}
+
+static int avahiFdconsume( int fdCount, fd_set* rfds, fd_set* wfds, fd_set* efds )
+{
+	int retval = fdCount;
+
+	AvahiWatch* w = avahiWatchList;
+	while( w != NULL && retval > 0 ) {
+		AvahiWatch* current = w;
+		current->observedEvent = 0;
+		if( FD_ISSET( current->fd, rfds ) ) {
+			current->observedEvent |= AVAHI_WATCH_IN;
+			FD_CLR( current->fd, rfds );
+			retval--;
+		}
+		if( FD_ISSET( current->fd, wfds ) ) {
+			current->observedEvent |= AVAHI_WATCH_OUT;
+			FD_CLR( current->fd, wfds );
+			retval--;
+		}
+		if( FD_ISSET( current->fd, efds ) ) {
+			current->observedEvent |= AVAHI_WATCH_ERR;
+			FD_CLR( current->fd, efds );
+			retval--;
+		}
+
+		/* Advance to the next one right now, in case the callback
+		 * removes itself
+		 */
+		w = w->next;
+
+		if( current->observedEvent && avahiRunning ) {
+			current->callback( current, current->fd,
+					current->observedEvent, current->userdata );
+		}
+	}
+
+	AvahiTimeout* t = avahiTimeoutList;
+	while( t != NULL && avahiRunning ) {
+		AvahiTimeout* current = t;
+
+		/* Advance to the next one right now, in case the callback
+		 * removes itself
+		 */
+		t = t->next;
+		avahiCheckExpiry( current );
+	}
+
+	return retval;
+}
+
+#endif // HAVE_AVAHI
+
+void initZeroconf(void)
+{
+	const char* serviceName = SERVICE_NAME;
+	ConfigParam *param;
+
+	param = getConfigParam(CONF_ZEROCONF_NAME);
+
+	if (param && strlen(param->value) > 0)
+		serviceName = param->value;
+
+#if HAVE_AVAHI
+	int error;
+	DEBUG( "Avahi: Initializing interface\n" );
+
+	if( avahi_is_valid_service_name( serviceName ) ) {
+		avahiName = avahi_strdup( serviceName );
+	} else {
+		ERROR( "Invalid zeroconf_name \"%s\", defaulting to \"%s\" instead.\n", serviceName, SERVICE_NAME );
+		avahiName = avahi_strdup( SERVICE_NAME );
+	}
+
+	avahiRunning = 1;
+
+	avahiPoll.userdata = NULL;
+	avahiPoll.watch_new = avahiWatchNew;
+	avahiPoll.watch_update = avahiWatchUpdate;
+	avahiPoll.watch_get_events = avahiWatchGetEvents;
+	avahiPoll.watch_free = avahiWatchFree;
+	avahiPoll.timeout_new = avahiTimeoutNew;
+	avahiPoll.timeout_update = avahiTimeoutUpdate;
+	avahiPoll.timeout_free = avahiTimeoutFree;
+
+	avahiClient = avahi_client_new( &avahiPoll, AVAHI_CLIENT_NO_FAIL,
+			avahiClientCallback, NULL, &error );
+
+	if( !avahiClient ) {
+		ERROR( "Avahi: Failed to create client: %s\n", avahi_strerror(error) );
+		goto fail;
+	}
+
+	avahiIo.fdset = avahiFdset;
+	avahiIo.consume = avahiFdconsume;
+	registerIO( &avahiIo );
+
+	return;
+
+fail:
+	finishZeroconf();
+#endif // HAVE_AVAHI
+}
+
+void finishZeroconf(void)
+{
+#if HAVE_AVAHI
+	DEBUG( "Avahi: Shutting down interface\n" );
+	deregisterIO( &avahiIo );
+
+	if( avahiGroup ) {
+		avahi_entry_group_free( avahiGroup );
+		avahiGroup = NULL;
+	}
+
+	if( avahiClient ) {
+		avahi_client_free( avahiClient );
+		avahiClient = NULL;
+	}
+
+	avahi_free( avahiName );
+	avahiName = NULL;
+#endif // HAVE_AVAHI
+}