* split off lookup.h and publish.h from core.h

* implement wide-area DNS-SD
* if multiple clients query the same records, only start the query packet sequence once
* implement recursive CNAME queries
* add support for resolving services without TXT or A/AAAA records
* enlarge resolving timeouts to 5s
* implement new browse/resolving events CACHE_EXHAUSTED/ALL_FOR_NOW 
* add support for resolving services without name. (i.e. for normal SRV records)


git-svn-id: file:///home/lennart/svn/public/avahi/trunk@608 941a03a8-eaeb-0310-b9a0-b1bbd8fe43fe

1 files changed, 200 insertions, 0 deletions

diff --git a/avahi-core/querier.c b/avahi-core/querier.c
new file mode 100644
index 0000000..51b2ce6
--- /dev/null
+++ b/avahi-core/querier.c
@@ -0,0 +1,200 @@
+/* $Id$ */
+
+/***
+  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 <avahi-common/timeval.h>
+#include <avahi-common/malloc.h>
+#include <avahi-common/error.h>
+#include <avahi-common/domain.h>
+
+#include "querier.h"
+#include "log.h"
+
+struct AvahiQuerier {
+    AvahiInterface *interface;
+
+    AvahiKey *key;
+    int n_used;
+
+    unsigned sec_delay;
+
+    AvahiTimeEvent *time_event;
+
+    struct timeval creation_time;
+    
+    AVAHI_LLIST_FIELDS(AvahiQuerier, queriers);
+};
+
+void avahi_querier_free(AvahiQuerier *q) {
+    assert(q);
+
+    AVAHI_LLIST_REMOVE(AvahiQuerier, queriers, q->interface->queriers, q);
+    avahi_hashmap_remove(q->interface->queriers_by_key, q->key);
+
+    avahi_key_unref(q->key);
+    avahi_time_event_free(q->time_event);
+    
+    avahi_free(q);
+}
+
+static void querier_elapse_callback(AvahiTimeEvent *e, void *userdata) {
+    AvahiQuerier *q = userdata;
+    struct timeval tv;
+    
+    assert(q);
+
+    avahi_interface_post_query(q->interface, q->key, 0);
+
+    q->sec_delay *= 2;
+    
+    if (q->sec_delay >= 60*60)  /* 1h */
+        q->sec_delay = 60*60;
+    
+    avahi_elapse_time(&tv, q->sec_delay*1000, 0);
+    avahi_time_event_update(q->time_event, &tv);
+}
+
+void avahi_querier_add(AvahiInterface *i, AvahiKey *key, struct timeval *ret_ctime) {
+    AvahiQuerier *q;
+    struct timeval tv;
+    
+    assert(i);
+    assert(key);
+
+    if ((q = avahi_hashmap_lookup(i->queriers_by_key, key))) {
+        /* Someone is already browsing for records of this RR key */
+        q->n_used++;
+
+        /* Return the creation time */
+        if (ret_ctime)
+            *ret_ctime = q->creation_time;
+        return;
+    }
+
+    /* No one is browsing for this RR key, so we add a new querier */
+    if (!(q = avahi_new(AvahiQuerier, 1)))
+        return; /* OOM */
+    
+    q->key = avahi_key_ref(key);
+    q->interface = i;
+    q->n_used = 1;
+    q->sec_delay = 1;
+    gettimeofday(&q->creation_time, NULL);
+
+    /* Do the initial query */
+    avahi_interface_post_query(i, key, 0);
+
+    /* Schedule next queries */
+    q->time_event = avahi_time_event_new(i->monitor->server->time_event_queue, avahi_elapse_time(&tv, q->sec_delay*1000, 0), querier_elapse_callback, q);
+
+    AVAHI_LLIST_PREPEND(AvahiQuerier, queriers, i->queriers, q);
+    avahi_hashmap_insert(i->queriers_by_key, q->key, q);
+
+    /* Return the creation time */
+    if (ret_ctime)
+        *ret_ctime = q->creation_time;
+}
+
+void avahi_querier_remove(AvahiInterface *i, AvahiKey *key) {
+    AvahiQuerier *q;
+
+    if (!(q = avahi_hashmap_lookup(i->queriers_by_key, key))) {
+        /* The was no querier for this RR key */
+        avahi_log_warn(__FILE__": querier_remove() called but no querier to remove");
+        return;
+    }
+
+    assert(q->n_used >= 1);
+    if ((--q->n_used) <= 0)
+        avahi_querier_free(q);
+}
+
+static void remove_querier_callback(AvahiInterfaceMonitor *m, AvahiInterface *i, void* userdata) {
+    assert(m);
+    assert(i);
+    assert(userdata);
+
+    if (i->announcing)
+        avahi_querier_remove(i, (AvahiKey*) userdata);
+}
+
+void avahi_querier_remove_for_all(AvahiServer *s, AvahiIfIndex idx, AvahiProtocol protocol, AvahiKey *key) {
+    assert(s);
+    assert(key);
+    
+    avahi_interface_monitor_walk(s->monitor, idx, protocol, remove_querier_callback, key);
+}
+
+struct cbdata {
+    AvahiKey *key;
+    struct timeval *ret_ctime;
+};
+
+static void add_querier_callback(AvahiInterfaceMonitor *m, AvahiInterface *i, void* userdata) {
+    struct cbdata *cbdata = userdata;
+    
+    assert(m);
+    assert(i);
+    assert(cbdata);
+
+    if (i->announcing) {
+        struct timeval tv;
+        avahi_querier_add(i, cbdata->key, &tv);
+
+        if (cbdata->ret_ctime && avahi_timeval_compare(&tv, cbdata->ret_ctime) > 0)
+            *cbdata->ret_ctime = tv;
+    }
+}
+
+void avahi_querier_add_for_all(AvahiServer *s, AvahiIfIndex idx, AvahiProtocol protocol, AvahiKey *key, struct timeval *ret_ctime) {
+    struct cbdata cbdata;
+    
+    assert(s);
+    assert(key);
+
+    cbdata.key = key;
+    cbdata.ret_ctime = ret_ctime;
+
+    if (ret_ctime)
+        ret_ctime->tv_sec = ret_ctime->tv_usec = 0;
+    
+    avahi_interface_monitor_walk(s->monitor, idx, protocol, add_querier_callback, &cbdata);
+}
+
+int avahi_querier_exists(AvahiInterface *i, AvahiKey *key) {
+    assert(i);
+    assert(key);
+
+    if (avahi_hashmap_lookup(i->queriers_by_key, key))
+        return 1;
+
+    return 0;
+}
+
+void avahi_querier_free_all(AvahiInterface *i) {
+    assert(i);
+
+    while (i->queriers) 
+        avahi_querier_free(i->queriers);
+}