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libvirt/daemon/mdns.c

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/*
* mdns.c: advertise libvirt hypervisor connections
*
* Copyright (C) 2007 Daniel P. Berrange
*
* Derived from Avahi example service provider code.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Author: Daniel P. Berrange <berrange@redhat.com>
*/
#include <config.h>
#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <avahi-client/client.h>
#include <avahi-client/publish.h>
#include <avahi-common/alternative.h>
#include <avahi-common/simple-watch.h>
#include <avahi-common/malloc.h>
#include <avahi-common/error.h>
#include <avahi-common/timeval.h>
#include "libvirtd.h"
#include "mdns.h"
#include "event.h"
#include "event_poll.h"
#include "memory.h"
#define AVAHI_DEBUG(fmt, ...) VIR_DEBUG(fmt, __VA_ARGS__)
struct libvirtd_mdns_entry {
char *type;
int port;
struct libvirtd_mdns_entry *next;
};
struct libvirtd_mdns_group {
struct libvirtd_mdns *mdns;
AvahiEntryGroup *handle;
char *name;
struct libvirtd_mdns_entry *entry;
struct libvirtd_mdns_group *next;
};
struct libvirtd_mdns {
AvahiClient *client;
AvahiPoll *poller;
struct libvirtd_mdns_group *group;
};
/* Avahi API requires this struct names in the app :-( */
struct AvahiWatch {
int watch;
int fd;
int revents;
AvahiWatchCallback callback;
void *userdata;
};
/* Avahi API requires this struct names in the app :-( */
struct AvahiTimeout {
int timer;
AvahiTimeoutCallback callback;
void *userdata;
};
static void libvirtd_mdns_create_services(struct libvirtd_mdns_group *group);
/* Called whenever the entry group state changes */
static void libvirtd_mdns_group_callback(AvahiEntryGroup *g ATTRIBUTE_UNUSED, AvahiEntryGroupState state, void *userdata) {
struct libvirtd_mdns_group *group = (struct libvirtd_mdns_group *)userdata;
switch (state) {
case AVAHI_ENTRY_GROUP_ESTABLISHED:
/* The entry group has been established successfully */
AVAHI_DEBUG("Group '%s' established", group->name);
break;
case AVAHI_ENTRY_GROUP_COLLISION:
{
char *n;
/* A service name collision happened. Let's pick a new name */
n = avahi_alternative_service_name(group->name);
VIR_FREE(group->name);
group->name = n;
AVAHI_DEBUG("Group name collision, renaming service to '%s'", group->name);
/* And recreate the services */
libvirtd_mdns_create_services(group);
}
break;
case AVAHI_ENTRY_GROUP_FAILURE :
AVAHI_DEBUG("Group failure: %s", avahi_strerror(avahi_client_errno(group->mdns->client)));
/* Some kind of failure happened while we were registering our services */
//avahi_simple_poll_quit(simple_poll);
break;
case AVAHI_ENTRY_GROUP_UNCOMMITED:
case AVAHI_ENTRY_GROUP_REGISTERING:
;
}
}
static void libvirtd_mdns_create_services(struct libvirtd_mdns_group *group) {
struct libvirtd_mdns *mdns = group->mdns;
struct libvirtd_mdns_entry *entry;
int ret;
AVAHI_DEBUG("Adding services to '%s'", group->name);
/* If we've no services to advertise, just reset the group to make
* sure it is emptied of any previously advertised services */
if (!group->entry) {
if (group->handle)
avahi_entry_group_reset(group->handle);
return;
}
/* If this is the first time we're called, let's create a new entry group */
if (!group->handle) {
AVAHI_DEBUG("Creating initial group %s", group->name);
if (!(group->handle = avahi_entry_group_new(mdns->client, libvirtd_mdns_group_callback, group))) {
AVAHI_DEBUG("avahi_entry_group_new() failed: %s", avahi_strerror(avahi_client_errno(mdns->client)));
return;
}
}
entry = group->entry;
while (entry) {
if ((ret = avahi_entry_group_add_service(group->handle,
AVAHI_IF_UNSPEC,
AVAHI_PROTO_UNSPEC,
0,
group->name,
entry->type,
NULL,
NULL,
entry->port,
NULL)) < 0) {
AVAHI_DEBUG("Failed to add %s service on port %d: %s",
entry->type, entry->port, avahi_strerror(ret));
avahi_entry_group_reset(group->handle);
return;
}
entry = entry->next;
}
/* Tell the server to register the service */
if ((ret = avahi_entry_group_commit(group->handle)) < 0) {
avahi_entry_group_reset(group->handle);
AVAHI_DEBUG("Failed to commit entry_group: %s", avahi_strerror(ret));
return;
}
}
static void libvirtd_mdns_client_callback(AvahiClient *c, AvahiClientState state, void *userdata) {
struct libvirtd_mdns *mdns = (struct libvirtd_mdns *)userdata;
struct libvirtd_mdns_group *group;
if (!mdns->client)
mdns->client = c;
/* Called whenever the client or server state changes */
switch (state) {
case AVAHI_CLIENT_S_RUNNING:
/* The server has startup successfully and registered its host
* name on the network, so it's time to create our services */
AVAHI_DEBUG("Client running %p", mdns->client);
group = mdns->group;
while (group) {
libvirtd_mdns_create_services(group);
group = group->next;
}
break;
case AVAHI_CLIENT_FAILURE:
AVAHI_DEBUG("Client failure: %s", avahi_strerror(avahi_client_errno(c)));
libvirtd_mdns_stop(mdns);
libvirtd_mdns_start(mdns);
break;
case AVAHI_CLIENT_S_COLLISION:
/* 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. */
/* Fallthrough */
case AVAHI_CLIENT_S_REGISTERING:
/* 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 established. */
AVAHI_DEBUG("Client collision/connecting %p", mdns->client);
group = mdns->group;
while (group) {
if (group->handle)
avahi_entry_group_reset(group->handle);
group = group->next;
}
break;
case AVAHI_CLIENT_CONNECTING:
AVAHI_DEBUG("Client connecting.... %p", mdns->client);
;
}
}
static void libvirtd_mdns_watch_dispatch(int watch, int fd, int events, void *opaque)
{
AvahiWatch *w = (AvahiWatch*)opaque;
int fd_events = virEventPollToNativeEvents(events);
AVAHI_DEBUG("Dispatch watch %d FD %d Event %d", watch, fd, fd_events);
w->revents = fd_events;
w->callback(w, fd, fd_events, w->userdata);
}
static void libvirtd_mdns_watch_dofree(void *w)
{
VIR_FREE(w);
}
static AvahiWatch *libvirtd_mdns_watch_new(const AvahiPoll *api ATTRIBUTE_UNUSED,
int fd, AvahiWatchEvent event,
AvahiWatchCallback cb, void *userdata) {
AvahiWatch *w;
virEventHandleType hEvents;
if (VIR_ALLOC(w) < 0)
return NULL;
w->fd = fd;
w->revents = 0;
w->callback = cb;
w->userdata = userdata;
AVAHI_DEBUG("New handle %p FD %d Event %d", w, w->fd, event);
hEvents = virEventPollFromNativeEvents(event);
if ((w->watch = virEventAddHandle(fd, hEvents,
libvirtd_mdns_watch_dispatch,
w,
libvirtd_mdns_watch_dofree)) < 0) {
VIR_FREE(w);
return NULL;
}
return w;
}
static void libvirtd_mdns_watch_update(AvahiWatch *w, AvahiWatchEvent event)
{
AVAHI_DEBUG("Update handle %p FD %d Event %d", w, w->fd, event);
virEventUpdateHandle(w->watch, event);
}
static AvahiWatchEvent libvirtd_mdns_watch_get_events(AvahiWatch *w)
{
AVAHI_DEBUG("Get handle events %p %d", w, w->fd);
return w->revents;
}
static void libvirtd_mdns_watch_free(AvahiWatch *w)
{
AVAHI_DEBUG("Free handle %p %d", w, w->fd);
virEventRemoveHandle(w->watch);
}
static void libvirtd_mdns_timeout_dispatch(int timer ATTRIBUTE_UNUSED, void *opaque)
{
AvahiTimeout *t = (AvahiTimeout*)opaque;
AVAHI_DEBUG("Dispatch timeout %p %d", t, timer);
virEventUpdateTimeout(t->timer, -1);
t->callback(t, t->userdata);
}
static void libvirtd_mdns_timeout_dofree(void *t)
{
VIR_FREE(t);
}
static AvahiTimeout *libvirtd_mdns_timeout_new(const AvahiPoll *api ATTRIBUTE_UNUSED,
const struct timeval *tv,
AvahiTimeoutCallback cb,
void *userdata)
{
AvahiTimeout *t;
struct timeval now;
long long nowms, thenms, timeout;
AVAHI_DEBUG("Add timeout TV %p", tv);
if (VIR_ALLOC(t) < 0)
return NULL;
if (gettimeofday(&now, NULL) < 0) {
VIR_FREE(t);
return NULL;
}
AVAHI_DEBUG("Trigger timed for %d %d %d %d",
(int)now.tv_sec, (int)now.tv_usec,
(int)(tv ? tv->tv_sec : 0), (int)(tv ? tv->tv_usec : 0));
nowms = (now.tv_sec * 1000ll) + (now.tv_usec / 1000ll);
if (tv) {
thenms = (tv->tv_sec * 1000ll) + (tv->tv_usec/1000ll);
timeout = thenms > nowms ? nowms - thenms : 0;
if (timeout < 0)
timeout = 0;
} else {
timeout = -1;
}
t->timer = virEventAddTimeout(timeout,
libvirtd_mdns_timeout_dispatch,
t,
libvirtd_mdns_timeout_dofree);
t->callback = cb;
t->userdata = userdata;
if (t->timer < 0) {
VIR_FREE(t);
return NULL;
}
return t;
}
static void libvirtd_mdns_timeout_update(AvahiTimeout *t, const struct timeval *tv)
{
struct timeval now;
long long nowms, thenms, timeout;
AVAHI_DEBUG("Update timeout %p TV %p", t, tv);
if (gettimeofday(&now, NULL) < 0) {
VIR_FREE(t);
return;
}
nowms = (now.tv_sec * 1000ll) + (now.tv_usec / 1000ll);
if (tv) {
thenms = ((tv->tv_sec * 1000ll) + (tv->tv_usec/1000ll));
timeout = thenms > nowms ? nowms - thenms : 0;
if (timeout < 0)
timeout = 0;
} else {
timeout = -1;
}
virEventUpdateTimeout(t->timer, timeout);
}
static void libvirtd_mdns_timeout_free(AvahiTimeout *t)
{
AVAHI_DEBUG("Free timeout %p", t);
virEventRemoveTimeout(t->timer);
}
static AvahiPoll *libvirtd_create_poll(void)
{
AvahiPoll *p;
if (VIR_ALLOC(p) < 0)
return NULL;
p->userdata = NULL;
p->watch_new = libvirtd_mdns_watch_new;
p->watch_update = libvirtd_mdns_watch_update;
p->watch_get_events = libvirtd_mdns_watch_get_events;
p->watch_free = libvirtd_mdns_watch_free;
p->timeout_new = libvirtd_mdns_timeout_new;
p->timeout_update = libvirtd_mdns_timeout_update;
p->timeout_free = libvirtd_mdns_timeout_free;
return p;
}
struct libvirtd_mdns *libvirtd_mdns_new(void)
{
struct libvirtd_mdns *mdns;
if (VIR_ALLOC(mdns) < 0)
return NULL;
/* Allocate main loop object */
if (!(mdns->poller = libvirtd_create_poll())) {
VIR_FREE(mdns);
return NULL;
}
return mdns;
}
int libvirtd_mdns_start(struct libvirtd_mdns *mdns)
{
int error;
AVAHI_DEBUG("Starting client %p", mdns);
mdns->client = avahi_client_new(mdns->poller, AVAHI_CLIENT_NO_FAIL, libvirtd_mdns_client_callback, mdns, &error);
if (!mdns->client) {
AVAHI_DEBUG("Failed to create mDNS client: %s", avahi_strerror(error));
return -1;
}
return 0;
}
struct libvirtd_mdns_group *libvirtd_mdns_add_group(struct libvirtd_mdns *mdns, const char *name) {
struct libvirtd_mdns_group *group;
AVAHI_DEBUG("Adding group '%s'", name);
if (VIR_ALLOC(group) < 0)
return NULL;
if (!(group->name = strdup(name))) {
VIR_FREE(group);
return NULL;
}
group->mdns = mdns;
group->next = mdns->group;
mdns->group = group;
return group;
}
void libvirtd_mdns_remove_group(struct libvirtd_mdns *mdns, struct libvirtd_mdns_group *group) {
struct libvirtd_mdns_group *tmp = mdns->group, *prev = NULL;
while (tmp) {
if (tmp == group) {
VIR_FREE(group->name);
if (prev)
prev->next = group->next;
else
group->mdns->group = group->next;
VIR_FREE(group);
return;
}
prev = tmp;
tmp = tmp->next;
}
}
struct libvirtd_mdns_entry *libvirtd_mdns_add_entry(struct libvirtd_mdns_group *group, const char *type, int port) {
struct libvirtd_mdns_entry *entry;
AVAHI_DEBUG("Adding entry %s %d to group %s", type, port, group->name);
if (VIR_ALLOC(entry) < 0)
return NULL;
entry->port = port;
if (!(entry->type = strdup(type))) {
VIR_FREE(entry);
return NULL;
}
entry->next = group->entry;
group->entry = entry;
return entry;
}
void libvirtd_mdns_remove_entry(struct libvirtd_mdns_group *group, struct libvirtd_mdns_entry *entry) {
struct libvirtd_mdns_entry *tmp = group->entry, *prev = NULL;
while (tmp) {
if (tmp == entry) {
VIR_FREE(entry->type);
if (prev)
prev->next = entry->next;
else
group->entry = entry->next;
return;
}
prev = tmp;
tmp = tmp->next;
}
}
void libvirtd_mdns_stop(struct libvirtd_mdns *mdns)
{
struct libvirtd_mdns_group *group = mdns->group;
while (group) {
if (group->handle) {
avahi_entry_group_free(group->handle);
group->handle = NULL;
}
group = group->next;
}
if (mdns->client)
avahi_client_free(mdns->client);
mdns->client = NULL;
}
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