--- /dev/null
+/***
+ This file is part of avahi.
+
+ avahi 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.
+
+ avahi 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 avahi; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+ USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdlib.h>
+
+#include <avahi/timeval.h>
+#include <avahi/malloc.h>
+#include <avahi/error.h>
+#include <avahi/domain.h>
+#include <avahi/rlist.h>
+#include <avahi/address.h>
+#include <avahi/log.h>
+
+#include "browse.h"
+#include "querier.h"
+#include "domain-util.h"
+#include "rr-util.h"
+
+#define AVAHI_LOOKUPS_PER_BROWSER_MAX 15
+
+struct AvahiSRBLookup {
+ AvahiSRecordBrowser *record_browser;
+
+ unsigned ref;
+
+ AvahiIfIndex interface;
+ AvahiProtocol protocol;
+ AvahiLookupFlags flags;
+
+ AvahiKey *key;
+
+ AvahiWideAreaLookup *wide_area;
+ AvahiMulticastLookup *multicast;
+
+ AvahiRList *cname_lookups;
+
+ AVAHI_LLIST_FIELDS(AvahiSRBLookup, lookups);
+};
+
+static void lookup_handle_cname(AvahiSRBLookup *l, AvahiIfIndex interface, AvahiProtocol protocol, AvahiLookupFlags flags, AvahiRecord *r);
+static void lookup_drop_cname(AvahiSRBLookup *l, AvahiIfIndex interface, AvahiProtocol protocol, AvahiLookupFlags flags, AvahiRecord *r);
+
+static void transport_flags_from_domain(AvahiServer *s, AvahiLookupFlags *flags, const char *domain) {
+ assert(flags);
+ assert(domain);
+
+ assert(!((*flags & AVAHI_LOOKUP_USE_MULTICAST) && (*flags & AVAHI_LOOKUP_USE_WIDE_AREA)));
+
+ if (*flags & (AVAHI_LOOKUP_USE_MULTICAST|AVAHI_LOOKUP_USE_WIDE_AREA))
+ return;
+
+ if (!s->wide_area_lookup_engine ||
+ !avahi_wide_area_has_servers(s->wide_area_lookup_engine) ||
+ avahi_domain_ends_with(domain, AVAHI_MDNS_SUFFIX_LOCAL) ||
+ avahi_domain_ends_with(domain, AVAHI_MDNS_SUFFIX_ADDR_IPV4) ||
+ avahi_domain_ends_with(domain, AVAHI_MDNS_SUFFIX_ADDR_IPV6))
+ *flags |= AVAHI_LOOKUP_USE_MULTICAST;
+ else
+ *flags |= AVAHI_LOOKUP_USE_WIDE_AREA;
+}
+
+static AvahiSRBLookup* lookup_new(
+ AvahiSRecordBrowser *b,
+ AvahiIfIndex interface,
+ AvahiProtocol protocol,
+ AvahiLookupFlags flags,
+ AvahiKey *key) {
+
+ AvahiSRBLookup *l;
+
+ assert(b);
+ assert(AVAHI_IF_VALID(interface));
+ assert(AVAHI_PROTO_VALID(protocol));
+
+ if (b->n_lookups >= AVAHI_LOOKUPS_PER_BROWSER_MAX)
+ /* We don't like cyclic CNAMEs */
+ return NULL;
+
+ if (!(l = avahi_new(AvahiSRBLookup, 1)))
+ return NULL;
+
+ l->ref = 1;
+ l->record_browser = b;
+ l->interface = interface;
+ l->protocol = protocol;
+ l->key = avahi_key_ref(key);
+ l->wide_area = NULL;
+ l->multicast = NULL;
+ l->cname_lookups = NULL;
+ l->flags = flags;
+
+ transport_flags_from_domain(b->server, &l->flags, key->name);
+
+ AVAHI_LLIST_PREPEND(AvahiSRBLookup, lookups, b->lookups, l);
+
+ b->n_lookups ++;
+
+ return l;
+}
+
+static void lookup_unref(AvahiSRBLookup *l) {
+ assert(l);
+ assert(l->ref >= 1);
+
+ if (--l->ref >= 1)
+ return;
+
+ AVAHI_LLIST_REMOVE(AvahiSRBLookup, lookups, l->record_browser->lookups, l);
+ l->record_browser->n_lookups --;
+
+ if (l->wide_area) {
+ avahi_wide_area_lookup_free(l->wide_area);
+ l->wide_area = NULL;
+ }
+
+ if (l->multicast) {
+ avahi_multicast_lookup_free(l->multicast);
+ l->multicast = NULL;
+ }
+
+ while (l->cname_lookups) {
+ lookup_unref(l->cname_lookups->data);
+ l->cname_lookups = avahi_rlist_remove_by_link(l->cname_lookups, l->cname_lookups);
+ }
+
+ avahi_key_unref(l->key);
+ avahi_free(l);
+}
+
+static AvahiSRBLookup* lookup_ref(AvahiSRBLookup *l) {
+ assert(l);
+ assert(l->ref >= 1);
+
+ l->ref++;
+ return l;
+}
+
+static AvahiSRBLookup *lookup_find(
+ AvahiSRecordBrowser *b,
+ AvahiIfIndex interface,
+ AvahiProtocol protocol,
+ AvahiLookupFlags flags,
+ AvahiKey *key) {
+
+ AvahiSRBLookup *l;
+
+ assert(b);
+
+ for (l = b->lookups; l; l = l->lookups_next) {
+
+ if ((l->interface == AVAHI_IF_UNSPEC || l->interface == interface) &&
+ (l->interface == AVAHI_PROTO_UNSPEC || l->protocol == protocol) &&
+ l->flags == flags &&
+ avahi_key_equal(l->key, key))
+
+ return l;
+ }
+
+ return NULL;
+}
+
+static void browser_cancel(AvahiSRecordBrowser *b) {
+ assert(b);
+
+ if (b->root_lookup) {
+ lookup_unref(b->root_lookup);
+ b->root_lookup = NULL;
+ }
+
+ if (b->defer_time_event) {
+ avahi_time_event_free(b->defer_time_event);
+ b->defer_time_event = NULL;
+ }
+}
+
+static void lookup_wide_area_callback(
+ AvahiWideAreaLookupEngine *e,
+ AvahiBrowserEvent event,
+ AvahiLookupResultFlags flags,
+ AvahiRecord *r,
+ void *userdata) {
+
+ AvahiSRBLookup *l = userdata;
+ AvahiSRecordBrowser *b;
+
+ assert(e);
+ assert(l);
+ assert(l->ref >= 1);
+
+ b = l->record_browser;
+
+ if (b->dead)
+ return;
+
+ lookup_ref(l);
+
+ switch (event) {
+ case AVAHI_BROWSER_NEW:
+ assert(r);
+
+ if (r->key->clazz == AVAHI_DNS_CLASS_IN &&
+ r->key->type == AVAHI_DNS_TYPE_CNAME)
+ /* It's a CNAME record, so let's follow it. We only follow it on wide area DNS! */
+ lookup_handle_cname(l, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, AVAHI_LOOKUP_USE_WIDE_AREA, r);
+ else {
+ /* It's a normal record, so let's call the user callback */
+ assert(avahi_key_equal(r->key, l->key));
+
+ b->callback(b, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, event, r, flags, b->userdata);
+ }
+ break;
+
+ case AVAHI_BROWSER_REMOVE:
+ case AVAHI_BROWSER_CACHE_EXHAUSTED:
+ /* Not defined for wide area DNS */
+ abort();
+
+ case AVAHI_BROWSER_ALL_FOR_NOW:
+ case AVAHI_BROWSER_FAILURE:
+
+ b->callback(b, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, event, NULL, flags, b->userdata);
+ break;
+ }
+
+ lookup_unref(l);
+
+}
+
+static void lookup_multicast_callback(
+ AvahiMulticastLookupEngine *e,
+ AvahiIfIndex interface,
+ AvahiProtocol protocol,
+ AvahiBrowserEvent event,
+ AvahiLookupResultFlags flags,
+ AvahiRecord *r,
+ void *userdata) {
+
+ AvahiSRBLookup *l = userdata;
+ AvahiSRecordBrowser *b;
+
+ assert(e);
+ assert(l);
+
+ b = l->record_browser;
+
+ if (b->dead)
+ return;
+
+ lookup_ref(l);
+
+ switch (event) {
+ case AVAHI_BROWSER_NEW:
+ assert(r);
+
+ if (r->key->clazz == AVAHI_DNS_CLASS_IN &&
+ r->key->type == AVAHI_DNS_TYPE_CNAME)
+ /* It's a CNAME record, so let's follow it. We allow browsing on both multicast and wide area. */
+ lookup_handle_cname(l, interface, protocol, b->flags, r);
+ else {
+ /* It's a normal record, so let's call the user callback */
+
+ if (avahi_server_is_record_local(b->server, interface, protocol, r))
+ flags |= AVAHI_LOOKUP_RESULT_LOCAL;
+
+ b->callback(b, interface, protocol, event, r, flags, b->userdata);
+ }
+ break;
+
+ case AVAHI_BROWSER_REMOVE:
+ assert(r);
+
+ if (r->key->clazz == AVAHI_DNS_CLASS_IN &&
+ r->key->type == AVAHI_DNS_TYPE_CNAME)
+ /* It's a CNAME record, so let's drop that query! */
+ lookup_drop_cname(l, interface, protocol, 0, r);
+ else {
+ /* It's a normal record, so let's call the user callback */
+ assert(avahi_key_equal(b->key, l->key));
+
+ b->callback(b, interface, protocol, event, r, flags, b->userdata);
+ }
+ break;
+
+ case AVAHI_BROWSER_ALL_FOR_NOW:
+
+ b->callback(b, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, event, NULL, flags, b->userdata);
+ break;
+
+ case AVAHI_BROWSER_CACHE_EXHAUSTED:
+ case AVAHI_BROWSER_FAILURE:
+ /* Not defined for multicast DNS */
+ abort();
+
+ }
+
+ lookup_unref(l);
+}
+
+static int lookup_start(AvahiSRBLookup *l) {
+ assert(l);
+
+ assert(!(l->flags & AVAHI_LOOKUP_USE_WIDE_AREA) != !(l->flags & AVAHI_LOOKUP_USE_MULTICAST));
+ assert(!l->wide_area && !l->multicast);
+
+ if (l->flags & AVAHI_LOOKUP_USE_WIDE_AREA) {
+
+ if (!(l->wide_area = avahi_wide_area_lookup_new(l->record_browser->server->wide_area_lookup_engine, l->key, lookup_wide_area_callback, l)))
+ return -1;
+
+ } else {
+ assert(l->flags & AVAHI_LOOKUP_USE_MULTICAST);
+
+ if (!(l->multicast = avahi_multicast_lookup_new(l->record_browser->server->multicast_lookup_engine, l->interface, l->protocol, l->key, lookup_multicast_callback, l)))
+ return -1;
+ }
+
+ return 0;
+}
+
+static int lookup_scan_cache(AvahiSRBLookup *l) {
+ int n = 0;
+
+ assert(l);
+
+ assert(!(l->flags & AVAHI_LOOKUP_USE_WIDE_AREA) != !(l->flags & AVAHI_LOOKUP_USE_MULTICAST));
+
+
+ if (l->flags & AVAHI_LOOKUP_USE_WIDE_AREA) {
+ n = (int) avahi_wide_area_scan_cache(l->record_browser->server->wide_area_lookup_engine, l->key, lookup_wide_area_callback, l);
+
+ } else {
+ assert(l->flags & AVAHI_LOOKUP_USE_MULTICAST);
+ n = (int) avahi_multicast_lookup_engine_scan_cache(l->record_browser->server->multicast_lookup_engine, l->interface, l->protocol, l->key, lookup_multicast_callback, l);
+ }
+
+ return n;
+}
+
+static AvahiSRBLookup* lookup_add(AvahiSRecordBrowser *b, AvahiIfIndex interface, AvahiProtocol protocol, AvahiLookupFlags flags, AvahiKey *key) {
+ AvahiSRBLookup *l;
+
+ assert(b);
+ assert(!b->dead);
+
+ if ((l = lookup_find(b, interface, protocol, flags, key)))
+ return lookup_ref(l);
+
+ if (!(l = lookup_new(b, interface, protocol, flags, key)))
+ return NULL;
+
+ return l;
+}
+
+static int lookup_go(AvahiSRBLookup *l) {
+ int n = 0;
+ assert(l);
+
+ if (l->record_browser->dead)
+ return 0;
+
+ lookup_ref(l);
+
+ /* Browse the cache for the root request */
+ n = lookup_scan_cache(l);
+
+ /* Start the lookup */
+ if (!l->record_browser->dead && l->ref > 1) {
+
+ if ((l->flags & AVAHI_LOOKUP_USE_MULTICAST) || n == 0)
+ /* We do no start a query if the cache contained entries and we're on wide area */
+
+ if (lookup_start(l) < 0)
+ n = -1;
+ }
+
+ lookup_unref(l);
+
+ return n;
+}
+
+static void lookup_handle_cname(AvahiSRBLookup *l, AvahiIfIndex interface, AvahiProtocol protocol, AvahiLookupFlags flags, AvahiRecord *r) {
+ AvahiKey *k;
+ AvahiSRBLookup *n;
+
+ assert(l);
+ assert(r);
+
+ assert(r->key->clazz == AVAHI_DNS_CLASS_IN);
+ assert(r->key->type == AVAHI_DNS_TYPE_CNAME);
+
+ k = avahi_key_new(r->data.ptr.name, l->record_browser->key->clazz, l->record_browser->key->type);
+ n = lookup_add(l->record_browser, interface, protocol, flags, k);
+ avahi_key_unref(k);
+
+ if (!n) {
+ avahi_log_debug(__FILE__": Failed to create SRBLookup.");
+ return;
+ }
+
+ l->cname_lookups = avahi_rlist_prepend(l->cname_lookups, lookup_ref(n));
+
+ lookup_go(n);
+ lookup_unref(n);
+}
+
+static void lookup_drop_cname(AvahiSRBLookup *l, AvahiIfIndex interface, AvahiProtocol protocol, AvahiLookupFlags flags, AvahiRecord *r) {
+ AvahiKey *k;
+ AvahiSRBLookup *n = NULL;
+ AvahiRList *rl;
+
+ assert(r->key->clazz == AVAHI_DNS_CLASS_IN);
+ assert(r->key->type == AVAHI_DNS_TYPE_CNAME);
+
+ k = avahi_key_new(r->data.ptr.name, l->record_browser->key->clazz, l->record_browser->key->type);
+
+ for (rl = l->cname_lookups; rl; rl = rl->rlist_next) {
+ n = rl->data;
+
+ assert(n);
+
+ if ((n->interface == AVAHI_IF_UNSPEC || n->interface == interface) &&
+ (n->interface == AVAHI_PROTO_UNSPEC || n->protocol == protocol) &&
+ n->flags == flags &&
+ avahi_key_equal(n->key, k))
+ break;
+ }
+
+ avahi_key_unref(k);
+
+ if (rl) {
+ l->cname_lookups = avahi_rlist_remove_by_link(l->cname_lookups, rl);
+ lookup_unref(n);
+ }
+}
+
+static void defer_callback(AVAHI_GCC_UNUSED AvahiTimeEvent *e, void *userdata) {
+ AvahiSRecordBrowser *b = userdata;
+ int n;
+
+ assert(b);
+ assert(!b->dead);
+
+ /* Remove the defer timeout */
+ if (b->defer_time_event) {
+ avahi_time_event_free(b->defer_time_event);
+ b->defer_time_event = NULL;
+ }
+
+ /* Create initial query */
+ assert(!b->root_lookup);
+ b->root_lookup = lookup_add(b, b->interface, b->protocol, b->flags, b->key);
+ assert(b->root_lookup);
+
+ n = lookup_go(b->root_lookup);
+
+ if (b->dead)
+ return;
+
+ if (n < 0) {
+ /* sending of the initial query failed */
+
+ avahi_server_set_errno(b->server, AVAHI_ERR_FAILURE);
+
+ b->callback(
+ b, b->interface, b->protocol, AVAHI_BROWSER_FAILURE, NULL,
+ b->flags & AVAHI_LOOKUP_USE_WIDE_AREA ? AVAHI_LOOKUP_RESULT_WIDE_AREA : AVAHI_LOOKUP_RESULT_MULTICAST,
+ b->userdata);
+
+ browser_cancel(b);
+ return;
+ }
+
+ /* Tell the client that we're done with the cache */
+ b->callback(
+ b, b->interface, b->protocol, AVAHI_BROWSER_CACHE_EXHAUSTED, NULL,
+ b->flags & AVAHI_LOOKUP_USE_WIDE_AREA ? AVAHI_LOOKUP_RESULT_WIDE_AREA : AVAHI_LOOKUP_RESULT_MULTICAST,
+ b->userdata);
+
+ if (!b->dead && b->root_lookup && b->root_lookup->flags & AVAHI_LOOKUP_USE_WIDE_AREA && n > 0) {
+
+ /* If we do wide area lookups and the the cache contained
+ * entries, we assume that it is complete, and tell the user
+ * so by firing ALL_FOR_NOW. */
+
+ b->callback(b, b->interface, b->protocol, AVAHI_BROWSER_ALL_FOR_NOW, NULL, AVAHI_LOOKUP_RESULT_WIDE_AREA, b->userdata);
+ }
+}
+
+void avahi_s_record_browser_restart(AvahiSRecordBrowser *b) {
+ assert(b);
+ assert(!b->dead);
+
+ browser_cancel(b);
+
+ /* Request a new iteration of the cache scanning */
+ if (!b->defer_time_event) {
+ b->defer_time_event = avahi_time_event_new(b->server->time_event_queue, NULL, defer_callback, b);
+ assert(b->defer_time_event);
+ }
+}
+
+AvahiSRecordBrowser *avahi_s_record_browser_new(
+ AvahiServer *server,
+ AvahiIfIndex interface,
+ AvahiProtocol protocol,
+ AvahiKey *key,
+ AvahiLookupFlags flags,
+ AvahiSRecordBrowserCallback callback,
+ void* userdata) {
+
+ AvahiSRecordBrowser *b;
+
+ assert(server);
+ assert(key);
+ assert(callback);
+
+ AVAHI_CHECK_VALIDITY_RETURN_NULL(server, AVAHI_IF_VALID(interface), AVAHI_ERR_INVALID_INTERFACE);
+ AVAHI_CHECK_VALIDITY_RETURN_NULL(server, AVAHI_PROTO_VALID(protocol), AVAHI_ERR_INVALID_PROTOCOL);
+ AVAHI_CHECK_VALIDITY_RETURN_NULL(server, !avahi_key_is_pattern(key), AVAHI_ERR_IS_PATTERN);
+ AVAHI_CHECK_VALIDITY_RETURN_NULL(server, avahi_key_is_valid(key), AVAHI_ERR_INVALID_KEY);
+ AVAHI_CHECK_VALIDITY_RETURN_NULL(server, AVAHI_FLAGS_VALID(flags, AVAHI_LOOKUP_USE_WIDE_AREA|AVAHI_LOOKUP_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS);
+ AVAHI_CHECK_VALIDITY_RETURN_NULL(server, !(flags & AVAHI_LOOKUP_USE_WIDE_AREA) || !(flags & AVAHI_LOOKUP_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS);
+
+ if (!(b = avahi_new(AvahiSRecordBrowser, 1))) {
+ avahi_server_set_errno(server, AVAHI_ERR_NO_MEMORY);
+ return NULL;
+ }
+
+ b->dead = 0;
+ b->server = server;
+ b->interface = interface;
+ b->protocol = protocol;
+ b->key = avahi_key_ref(key);
+ b->flags = flags;
+ b->callback = callback;
+ b->userdata = userdata;
+ b->n_lookups = 0;
+ AVAHI_LLIST_HEAD_INIT(AvahiSRBLookup, b->lookups);
+ b->root_lookup = NULL;
+
+ AVAHI_LLIST_PREPEND(AvahiSRecordBrowser, browser, server->record_browsers, b);
+
+ /* The currently cached entries are scanned a bit later, and than we will start querying, too */
+ b->defer_time_event = avahi_time_event_new(server->time_event_queue, NULL, defer_callback, b);
+ assert(b->defer_time_event);
+
+ return b;
+}
+
+void avahi_s_record_browser_free(AvahiSRecordBrowser *b) {
+ assert(b);
+ assert(!b->dead);
+
+ b->dead = 1;
+ b->server->need_browser_cleanup = 1;
+
+ browser_cancel(b);
+}
+
+void avahi_s_record_browser_destroy(AvahiSRecordBrowser *b) {
+ assert(b);
+
+ browser_cancel(b);
+
+ AVAHI_LLIST_REMOVE(AvahiSRecordBrowser, browser, b->server->record_browsers, b);
+
+ avahi_key_unref(b->key);
+
+ avahi_free(b);
+}
+
+void avahi_browser_cleanup(AvahiServer *server) {
+ AvahiSRecordBrowser *b;
+ AvahiSRecordBrowser *n;
+
+ assert(server);
+
+ while (server->need_browser_cleanup) {
+ server->need_browser_cleanup = 0;
+
+ for (b = server->record_browsers; b; b = n) {
+ n = b->browser_next;
+
+ if (b->dead)
+ avahi_s_record_browser_destroy(b);
+ }
+ }
+
+ if (server->wide_area_lookup_engine)
+ avahi_wide_area_cleanup(server->wide_area_lookup_engine);
+ avahi_multicast_lookup_engine_cleanup(server->multicast_lookup_engine);
+}
+
projects / catta / blobdiff