Syncing wide-area branch to latest release.

git-svn-id: file:///home/lennart/svn/public/avahi/branches/federico@1397 941a03a8-eaeb-0310-b9a0-b1bbd8fe43fe

1 files changed, 508 insertions, 0 deletions

diff --git a/release-0.6.9/avahi-core/cache.c b/release-0.6.9/avahi-core/cache.c
new file mode 100644
index 0000000..3a8f849
--- /dev/null
+++ b/release-0.6.9/avahi-core/cache.c
@@ -0,0 +1,508 @@
+/* $Id$ */
+
+/***
+  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 <string.h>
+#include <stdlib.h>
+#include <time.h>
+
+#include <avahi-common/timeval.h>
+#include <avahi-common/malloc.h>
+
+#include "cache.h"
+#include "log.h"
+#include "rr-util.h"
+
+#define AVAHI_CACHE_ENTRIES_MAX 500
+
+static void remove_entry(AvahiCache *c, AvahiCacheEntry *e) {
+    AvahiCacheEntry *t;
+
+    assert(c);
+    assert(e);
+
+/*     avahi_log_debug("removing from cache: %p %p", c, e); */
+
+    /* Remove from hash table */
+    t = avahi_hashmap_lookup(c->hashmap, e->record->key);
+    AVAHI_LLIST_REMOVE(AvahiCacheEntry, by_key, t, e);
+    if (t)
+        avahi_hashmap_replace(c->hashmap, t->record->key, t);
+    else
+        avahi_hashmap_remove(c->hashmap, e->record->key);
+
+    /* Remove from linked list */
+    AVAHI_LLIST_REMOVE(AvahiCacheEntry, entry, c->entries, e);
+        
+    if (e->time_event)
+        avahi_time_event_free(e->time_event);
+
+    avahi_multicast_lookup_engine_notify(c->server->multicast_lookup_engine, c->interface, e->record, AVAHI_BROWSER_REMOVE);
+    
+    avahi_record_unref(e->record);
+    
+    avahi_free(e);
+
+    assert(c->n_entries-- >= 1);
+}
+
+AvahiCache *avahi_cache_new(AvahiServer *server, AvahiInterface *iface) {
+    AvahiCache *c;
+    assert(server);
+
+    if (!(c = avahi_new(AvahiCache, 1))) {
+        avahi_log_error(__FILE__": Out of memory.");
+        return NULL; /* OOM */
+    }
+    
+    c->server = server;
+    c->interface = iface;
+
+    if (!(c->hashmap = avahi_hashmap_new((AvahiHashFunc) avahi_key_hash, (AvahiEqualFunc) avahi_key_equal, NULL, NULL))) {
+        avahi_log_error(__FILE__": Out of memory.");
+        avahi_free(c);
+        return NULL; /* OOM */
+    }
+
+    AVAHI_LLIST_HEAD_INIT(AvahiCacheEntry, c->entries);
+    c->n_entries = 0;
+
+    c->last_rand_timestamp = 0;
+    
+    return c;
+}
+
+void avahi_cache_free(AvahiCache *c) {
+    assert(c);
+
+    while (c->entries)
+        remove_entry(c, c->entries);
+    assert(c->n_entries == 0);
+    
+    avahi_hashmap_free(c->hashmap);
+    
+    avahi_free(c);
+}
+
+static AvahiCacheEntry *lookup_key(AvahiCache *c, AvahiKey *k) {
+    assert(c);
+    assert(k);
+
+    assert(!avahi_key_is_pattern(k));
+    
+    return avahi_hashmap_lookup(c->hashmap, k);
+}
+
+void* avahi_cache_walk(AvahiCache *c, AvahiKey *pattern, AvahiCacheWalkCallback cb, void* userdata) {
+    void* ret;
+    
+    assert(c);
+    assert(pattern);
+    assert(cb);
+    
+    if (avahi_key_is_pattern(pattern)) {
+        AvahiCacheEntry *e, *n;
+        
+        for (e = c->entries; e; e = n) {
+            n = e->entry_next;
+            
+            if (avahi_key_pattern_match(pattern, e->record->key))
+                if ((ret = cb(c, pattern, e, userdata)))
+                    return ret;
+        }
+        
+    } else {
+        AvahiCacheEntry *e, *n;
+
+        for (e = lookup_key(c, pattern); e; e = n) {
+            n = e->by_key_next;
+                
+            if ((ret = cb(c, pattern, e, userdata)))
+                return ret;
+        }
+    }
+
+    return NULL;
+}
+
+static void* lookup_record_callback(AvahiCache *c, AvahiKey *pattern, AvahiCacheEntry *e, void *userdata) {
+    assert(c);
+    assert(pattern);
+    assert(e);
+
+    if (avahi_record_equal_no_ttl(e->record, userdata))
+        return e;
+
+    return NULL;
+}
+
+static AvahiCacheEntry *lookup_record(AvahiCache *c, AvahiRecord *r) {
+    assert(c);
+    assert(r);
+
+    return avahi_cache_walk(c, r->key, lookup_record_callback, r);
+}
+
+static void next_expiry(AvahiCache *c, AvahiCacheEntry *e, unsigned percent);
+
+static void elapse_func(AvahiTimeEvent *t, void *userdata) {
+    AvahiCacheEntry *e = userdata;
+/*     char *txt; */
+    unsigned percent = 0;
+    
+    assert(t);
+    assert(e);
+
+/*     txt = avahi_record_to_string(e->record); */
+
+    switch (e->state) {
+
+        case AVAHI_CACHE_EXPIRY_FINAL:
+        case AVAHI_CACHE_POOF_FINAL:
+        case AVAHI_CACHE_GOODBYE_FINAL:
+        case AVAHI_CACHE_REPLACE_FINAL:
+
+            remove_entry(e->cache, e);
+            
+            e = NULL;
+/*         avahi_log_debug("Removing entry from cache due to expiration (%s)", txt); */
+            break;
+            
+        case AVAHI_CACHE_VALID:
+        case AVAHI_CACHE_POOF:
+            e->state = AVAHI_CACHE_EXPIRY1;
+            percent = 85;
+            break;
+                
+        case AVAHI_CACHE_EXPIRY1:
+            e->state = AVAHI_CACHE_EXPIRY2;
+            percent = 90;
+            break;
+        case AVAHI_CACHE_EXPIRY2:
+            e->state = AVAHI_CACHE_EXPIRY3;
+            percent = 95;
+            break;
+            
+        case AVAHI_CACHE_EXPIRY3:
+            e->state = AVAHI_CACHE_EXPIRY_FINAL;
+            percent = 100;
+            break;
+    }
+
+    if (e) {
+
+        assert(percent > 0);
+
+        /* Request a cache update if we are subscribed to this entry */
+        if (avahi_querier_shall_refresh_cache(e->cache->interface, e->record->key))
+            avahi_interface_post_query(e->cache->interface, e->record->key, 0, NULL);
+        
+        /* Check again later */
+        next_expiry(e->cache, e, percent);
+        
+    }
+
+/*     avahi_free(txt); */
+}
+
+static void update_time_event(AvahiCache *c, AvahiCacheEntry *e) {
+    assert(c);
+    assert(e);
+    
+    if (e->time_event)
+        avahi_time_event_update(e->time_event, &e->expiry);
+    else
+        e->time_event = avahi_time_event_new(c->server->time_event_queue, &e->expiry, elapse_func, e);
+}
+
+static void next_expiry(AvahiCache *c, AvahiCacheEntry *e, unsigned percent) {
+    AvahiUsec usec, left, right;
+    time_t now;
+    
+    assert(c);
+    assert(e);
+    assert(percent > 0 && percent <= 100);
+    
+    usec = (AvahiUsec) e->record->ttl * 10000;
+
+    left = usec * percent;
+    right = usec * (percent+2); /* 2% jitter */
+
+    now = time(NULL);
+
+    if (now >= c->last_rand_timestamp + 10) {
+        c->last_rand = rand();
+        c->last_rand_timestamp = now;
+    }
+
+    usec = left + (AvahiUsec) ((double) (right-left) * c->last_rand / (RAND_MAX+1.0));
+    
+    e->expiry = e->timestamp;
+    avahi_timeval_add(&e->expiry, usec);
+    
+/*     g_message("wake up in +%lu seconds", e->expiry.tv_sec - e->timestamp.tv_sec); */
+    
+    update_time_event(c, e);
+}
+
+static void expire_in_one_second(AvahiCache *c, AvahiCacheEntry *e, AvahiCacheEntryState state) {
+    assert(c);
+    assert(e);
+    
+    e->state = state;
+    gettimeofday(&e->expiry, NULL);
+    avahi_timeval_add(&e->expiry, 1000000); /* 1s */
+    update_time_event(c, e);
+}
+
+void avahi_cache_update(AvahiCache *c, AvahiRecord *r, int cache_flush, const AvahiAddress *a) {
+/*     char *txt; */
+    
+    assert(c);
+    assert(r && r->ref >= 1);
+
+/*     txt = avahi_record_to_string(r); */
+
+    if (r->ttl == 0) {
+        /* This is a goodbye request */
+
+        AvahiCacheEntry *e;
+
+        if ((e = lookup_record(c, r)))
+            expire_in_one_second(c, e, AVAHI_CACHE_GOODBYE_FINAL);
+
+    } else {
+        AvahiCacheEntry *e = NULL, *first;
+        struct timeval now;
+
+        gettimeofday(&now, NULL);
+
+        /* This is an update request */
+
+        if ((first = lookup_key(c, r->key))) {
+            
+            if (cache_flush) {
+
+                /* For unique entries drop all entries older than one second */
+                for (e = first; e; e = e->by_key_next) {
+                    AvahiUsec t;
+
+                    t = avahi_timeval_diff(&now, &e->timestamp);
+
+                    if (t > 1000000)
+                        expire_in_one_second(c, e, AVAHI_CACHE_REPLACE_FINAL);
+                }
+            }
+                
+            /* Look for exactly the same entry */
+            for (e = first; e; e = e->by_key_next)
+                if (avahi_record_equal_no_ttl(e->record, r))
+                    break;
+        }
+    
+        if (e) {
+            
+/*             avahi_log_debug("found matching cache entry");  */
+
+            /* We need to update the hash table key if we replace the
+             * record */
+            if (e->by_key_prev == NULL)
+                avahi_hashmap_replace(c->hashmap, r->key, e);
+            
+            /* Update the record */
+            avahi_record_unref(e->record);
+            e->record = avahi_record_ref(r);
+
+/*             avahi_log_debug("cache: updating %s", txt);   */
+            
+        } else {
+            /* No entry found, therefore we create a new one */
+            
+/*             avahi_log_debug("cache: couldn't find matching cache entry for %s", txt);   */
+
+            if (c->n_entries >= AVAHI_CACHE_ENTRIES_MAX)
+                return;
+
+            if (!(e = avahi_new(AvahiCacheEntry, 1))) {
+                avahi_log_error(__FILE__": Out of memory");
+                return;
+            }
+
+            e->cache = c;
+            e->time_event = NULL;
+            e->record = avahi_record_ref(r);
+
+            /* Append to hash table */
+            AVAHI_LLIST_PREPEND(AvahiCacheEntry, by_key, first, e);
+            avahi_hashmap_replace(c->hashmap, e->record->key, first);
+
+            /* Append to linked list */
+            AVAHI_LLIST_PREPEND(AvahiCacheEntry, entry, c->entries, e);
+
+            c->n_entries++;
+
+            /* Notify subscribers */
+            avahi_multicast_lookup_engine_notify(c->server->multicast_lookup_engine, c->interface, e->record, AVAHI_BROWSER_NEW);
+        } 
+        
+        e->origin = *a;
+        e->timestamp = now;
+        next_expiry(c, e, 80);
+        e->state = AVAHI_CACHE_VALID;
+        e->cache_flush = cache_flush;
+    }
+
+/*     avahi_free(txt);  */
+}
+
+struct dump_data {
+    AvahiDumpCallback callback;
+    void* userdata;
+};
+
+static void dump_callback(void* key, void* data, void* userdata) {
+    AvahiCacheEntry *e = data;
+    AvahiKey *k = key;
+    struct dump_data *dump_data = userdata;
+
+    assert(k);
+    assert(e);
+    assert(data);
+
+    for (; e; e = e->by_key_next) {
+        char *t;
+
+        if (!(t = avahi_record_to_string(e->record)))
+            continue; /* OOM */
+        
+        dump_data->callback(t, dump_data->userdata);
+        avahi_free(t);
+    }
+}
+
+int avahi_cache_dump(AvahiCache *c, AvahiDumpCallback callback, void* userdata) {
+    struct dump_data data;
+
+    assert(c);
+    assert(callback);
+
+    callback(";;; CACHE DUMP FOLLOWS ;;;", userdata);
+
+    data.callback = callback;
+    data.userdata = userdata;
+
+    avahi_hashmap_foreach(c->hashmap, dump_callback, &data);
+
+    return 0;
+}
+
+int avahi_cache_entry_half_ttl(AvahiCache *c, AvahiCacheEntry *e) {
+    struct timeval now;
+    unsigned age;
+    
+    assert(c);
+    assert(e);
+
+    gettimeofday(&now, NULL);
+
+    age = (unsigned) (avahi_timeval_diff(&now, &e->timestamp)/1000000);
+
+/*     avahi_log_debug("age: %lli, ttl/2: %u", age, e->record->ttl);  */
+    
+    return age >= e->record->ttl/2;
+}
+
+void avahi_cache_flush(AvahiCache *c) {
+    assert(c);
+
+    while (c->entries)
+        remove_entry(c, c->entries);
+}
+
+/*** Passive observation of failure ***/
+
+static void* start_poof_callback(AvahiCache *c, AvahiKey *pattern, AvahiCacheEntry *e, void *userdata) {
+    AvahiAddress *a = userdata;
+
+    assert(c);
+    assert(pattern);
+    assert(e);
+    assert(a);
+    
+    switch (e->state) {
+        case AVAHI_CACHE_VALID:
+
+            /* The entry was perfectly valid till, now, so let's enter
+             * POOF mode */
+
+            e->state = AVAHI_CACHE_POOF;
+            e->poof_address = *a;
+            
+            break;
+
+        case AVAHI_CACHE_POOF:
+
+            /* This is the second time we got no response, so let's
+             * fucking remove this entry. */
+            
+            expire_in_one_second(c, e, AVAHI_CACHE_POOF_FINAL);
+            break;
+
+        default:
+            ;
+    }
+    
+    return NULL;
+}
+
+void avahi_cache_start_poof(AvahiCache *c, AvahiKey *key, const AvahiAddress *a) {
+    assert(c);
+    assert(key);
+
+    avahi_cache_walk(c, key, start_poof_callback, a);
+}
+
+void avahi_cache_stop_poof(AvahiCache *c, AvahiRecord *record, const AvahiAddress *a) {
+    AvahiCacheEntry *e;
+
+    assert(c);
+    assert(record);
+    assert(a);
+
+    if (!(e = lookup_record(c, record)))
+        return;
+
+    /* This function is called for each response suppression
+       record. If the matching cache entry is in POOF state and the
+       query address is the same, we put it back into valid mode */
+
+    if (e->state == AVAHI_CACHE_POOF || e->state == AVAHI_CACHE_POOF_FINAL)
+        if (avahi_address_cmp(a, &e->poof_address) == 0) {
+            e->state = AVAHI_CACHE_VALID;
+            next_expiry(c, e, 80);
+        }
+}
+
+
+