char *avahi_address_snprint(char *s, size_t length, const AvahiAddress *a) {
assert(s);
assert(length);
assert(a);
if (!(inet_ntop(avahi_proto_to_af(a->proto), a->data.data, s, length)))
return NULL;
return s;
}
static void
browse_record_callback(AvahiRecordBrowser *b, AvahiIfIndex intf, AvahiProtocol proto,
AvahiBrowserEvent event, const char *hostname, uint16_t clazz, uint16_t type,
const void *rdata, size_t size, AvahiLookupResultFlags flags, void *userdata)
{
struct mdns_record_browser *rb_data;
AvahiAddress addr;
char address[AVAHI_ADDRESS_STR_MAX];
int family;
int ret;
rb_data = (struct mdns_record_browser *)userdata;
if (event == AVAHI_BROWSER_CACHE_EXHAUSTED)
DPRINTF(E_DBG, L_MDNS, "Avahi Record Browser (%s, proto %d): no more results (CACHE_EXHAUSTED)\n", hostname, proto);
else if (event == AVAHI_BROWSER_ALL_FOR_NOW)
DPRINTF(E_DBG, L_MDNS, "Avahi Record Browser (%s, proto %d): no more results (ALL_FOR_NOW)\n", hostname, proto);
else if (event == AVAHI_BROWSER_FAILURE)
DPRINTF(E_LOG, L_MDNS, "Avahi Record Browser (%s, proto %d) failure: %s\n", hostname, proto, MDNSERR);
else if (event == AVAHI_BROWSER_REMOVE)
return; // Not handled - record browser lifetime too short for this to happen
if (event != AVAHI_BROWSER_NEW)
goto out_free_record_browser;
ret = avahi_address_make(&addr, proto, rdata, size); // Not an avahi function despite the name
if (ret < 0)
return;
family = avahi_proto_to_af(proto);
avahi_address_snprint(address, sizeof(address), &addr);
// Avahi will sometimes give us link-local addresses in 169.254.0.0/16 or
// fe80::/10, which (most of the time) are useless
// - see also https://lists.freedesktop.org/archives/avahi/2012-September/002183.html
if ((proto == AVAHI_PROTO_INET && is_v4ll(&addr.data.ipv4)) || (proto == AVAHI_PROTO_INET6 && is_v6ll(&addr.data.ipv6)))
{
DPRINTF(E_WARN, L_MDNS, "Ignoring announcement from %s, address %s is link-local\n", hostname, address);
return;
}
DPRINTF(E_DBG, L_MDNS, "Avahi Record Browser (%s, proto %d): NEW record %s for service type '%s'\n", hostname, proto, address, rb_data->mb->type);
// Execute callback (mb->cb) with all the data
rb_data->mb->cb(rb_data->name, rb_data->mb->type, rb_data->domain, hostname, family, address, rb_data->port, &rb_data->txt_kv);
// Stop record browser
out_free_record_browser:
keyval_clear(&rb_data->txt_kv);
free(rb_data->name);
free(rb_data->domain);
free(rb_data);
avahi_record_browser_free(b);
}
static void
browse_callback(AvahiServiceBrowser *b, AvahiIfIndex intf, AvahiProtocol proto, AvahiBrowserEvent event,
const char *name, const char *type, const char *domain, AvahiLookupResultFlags flags, void *userdata)
{
struct mdns_browser *mb;
struct mdns_resolver *r;
int family;
mb = (struct mdns_browser *)userdata;
switch (event)
{
case AVAHI_BROWSER_FAILURE:
DPRINTF(E_LOG, L_MDNS, "Avahi Browser failure: %s\n", MDNSERR);
avahi_service_browser_free(b);
b = avahi_service_browser_new(mdns_client, AVAHI_IF_UNSPEC, mb->protocol, mb->type, NULL, 0, browse_callback, mb);
if (!b)
{
DPRINTF(E_LOG, L_MDNS, "Failed to recreate service browser (service type %s): %s\n", mb->type, MDNSERR);
return;
}
break;
case AVAHI_BROWSER_NEW:
DPRINTF(E_DBG, L_MDNS, "Avahi Browser: NEW service '%s' type '%s' proto %d\n", name, type, proto);
CHECK_NULL(L_MDNS, r = calloc(1, sizeof(struct mdns_resolver)));
r->resolver = avahi_service_resolver_new(mdns_client, intf, proto, name, type, domain, proto, 0, browse_resolve_callback, mb);
if (!r->resolver)
{
DPRINTF(E_LOG, L_MDNS, "Failed to create service resolver: %s\n", MDNSERR);
free(r);
return;
}
r->name = strdup(name);
r->proto = proto;
r->next = resolver_list;
resolver_list = r;
break;
case AVAHI_BROWSER_REMOVE:
DPRINTF(E_DBG, L_MDNS, "Avahi Browser: REMOVE service '%s' type '%s' proto %d\n", name, type, proto);
family = avahi_proto_to_af(proto);
if (family != AF_UNSPEC)
mb->cb(name, type, domain, NULL, family, NULL, -1, NULL);
resolvers_cleanup(name, proto);
break;
case AVAHI_BROWSER_ALL_FOR_NOW:
case AVAHI_BROWSER_CACHE_EXHAUSTED:
DPRINTF(E_DBG, L_MDNS, "Avahi Browser (%s): no more results (%s)\n", mb->type,
(event == AVAHI_BROWSER_CACHE_EXHAUSTED) ? "CACHE_EXHAUSTED" : "ALL_FOR_NOW");
break;
}
}
static void
browse_resolve_callback(AvahiServiceResolver *r, AvahiIfIndex intf, AvahiProtocol proto, AvahiResolverEvent event,
const char *name, const char *type, const char *domain, const char *hostname, const AvahiAddress *addr,
uint16_t port, AvahiStringList *txt, AvahiLookupResultFlags flags, void *userdata)
{
AvahiRecordBrowser *rb;
struct mdns_browser *mb;
struct mdns_record_browser *rb_data;
char *key;
char *value;
uint16_t dns_type;
int family;
int ret;
mb = (struct mdns_browser *)userdata;
if (event != AVAHI_RESOLVER_FOUND)
{
if (event == AVAHI_RESOLVER_FAILURE)
DPRINTF(E_LOG, L_MDNS, "Avahi Resolver failure: service '%s' type '%s' proto %d: %s\n", name, type, proto, MDNSERR);
else
DPRINTF(E_LOG, L_MDNS, "Avahi Resolver empty callback\n");
family = avahi_proto_to_af(proto);
if (family != AF_UNSPEC)
mb->cb(name, type, domain, NULL, family, NULL, -1, NULL);
// We don't clean up resolvers because we want a notification from them if
// the service reappears (e.g. if device was switched off and then on)
return;
}
DPRINTF(E_DBG, L_MDNS, "Avahi Resolver: resolved service '%s' type '%s' proto %d, host %s\n", name, type, proto, hostname);
CHECK_NULL(L_MDNS, rb_data = calloc(1, sizeof(struct mdns_record_browser)));
rb_data->name = strdup(name);
rb_data->domain = strdup(domain);
rb_data->mb = mb;
rb_data->port = port;
while (txt)
{
ret = avahi_string_list_get_pair(txt, &key, &value, NULL);
txt = avahi_string_list_get_next(txt);
if (ret < 0)
continue;
if (value)
{
keyval_add(&rb_data->txt_kv, key, value);
avahi_free(value);
}
avahi_free(key);
}
if (proto == AVAHI_PROTO_INET6)
dns_type = AVAHI_DNS_TYPE_AAAA;
else
dns_type = AVAHI_DNS_TYPE_A;
// We need to implement a record browser because the announcement from some
// devices (e.g. ApEx 1 gen) will include multiple records, and we need to
// filter out those records that won't work (notably link-local). The value of
// *addr given by browse_resolve_callback is just the first record.
rb = avahi_record_browser_new(mdns_client, intf, proto, hostname, AVAHI_DNS_CLASS_IN, dns_type, 0, browse_record_callback, rb_data);
if (!rb)
DPRINTF(E_LOG, L_MDNS, "Could not create record browser for host %s: %s\n", hostname, MDNSERR);
}