mpd/src/zeroconf.c

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/* 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;
AvahiTimeout* t;
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 );
}
}
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;
}
static void init_avahi(const char *serviceName)
{
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();
}
#else /* !HAVE_AVAHI */
static void init_avahi(const char *serviceName) { }
#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;
init_avahi(serviceName);
}
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
}