--- /dev/null
+/***
+ This file is part of catta.
+
+ catta 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.
+
+ catta 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 catta; 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 <catta/timeval.h>
+#include <catta/malloc.h>
+#include <catta/log.h>
+
+#include "cache.h"
+#include "rr-util.h"
+
+static void remove_entry(CattaCache *c, CattaCacheEntry *e) {
+ CattaCacheEntry *t;
+
+ assert(c);
+ assert(e);
+
+/* catta_log_debug("removing from cache: %p %p", c, e); */
+
+ /* Remove from hash table */
+ t = catta_hashmap_lookup(c->hashmap, e->record->key);
+ CATTA_LLIST_REMOVE(CattaCacheEntry, by_key, t, e);
+ if (t)
+ catta_hashmap_replace(c->hashmap, t->record->key, t);
+ else
+ catta_hashmap_remove(c->hashmap, e->record->key);
+
+ /* Remove from linked list */
+ CATTA_LLIST_REMOVE(CattaCacheEntry, entry, c->entries, e);
+
+ if (e->time_event)
+ catta_time_event_free(e->time_event);
+
+ catta_multicast_lookup_engine_notify(c->server->multicast_lookup_engine, c->iface, e->record, CATTA_BROWSER_REMOVE);
+
+ catta_record_unref(e->record);
+
+ catta_free(e);
+
+ assert(c->n_entries >= 1);
+ --c->n_entries;
+}
+
+CattaCache *catta_cache_new(CattaServer *server, CattaInterface *iface) {
+ CattaCache *c;
+ assert(server);
+
+ if (!(c = catta_new(CattaCache, 1))) {
+ catta_log_error(__FILE__": Out of memory.");
+ return NULL; /* OOM */
+ }
+
+ c->server = server;
+ c->iface = iface;
+
+ if (!(c->hashmap = catta_hashmap_new((CattaHashFunc) catta_key_hash, (CattaEqualFunc) catta_key_equal, NULL, NULL))) {
+ catta_log_error(__FILE__": Out of memory.");
+ catta_free(c);
+ return NULL; /* OOM */
+ }
+
+ CATTA_LLIST_HEAD_INIT(CattaCacheEntry, c->entries);
+ c->n_entries = 0;
+
+ c->last_rand_timestamp = 0;
+
+ return c;
+}
+
+void catta_cache_free(CattaCache *c) {
+ assert(c);
+
+ while (c->entries)
+ remove_entry(c, c->entries);
+ assert(c->n_entries == 0);
+
+ catta_hashmap_free(c->hashmap);
+
+ catta_free(c);
+}
+
+static CattaCacheEntry *lookup_key(CattaCache *c, CattaKey *k) {
+ assert(c);
+ assert(k);
+
+ assert(!catta_key_is_pattern(k));
+
+ return catta_hashmap_lookup(c->hashmap, k);
+}
+
+void* catta_cache_walk(CattaCache *c, CattaKey *pattern, CattaCacheWalkCallback cb, void* userdata) {
+ void* ret;
+
+ assert(c);
+ assert(pattern);
+ assert(cb);
+
+ if (catta_key_is_pattern(pattern)) {
+ CattaCacheEntry *e, *n;
+
+ for (e = c->entries; e; e = n) {
+ n = e->entry_next;
+
+ if (catta_key_pattern_match(pattern, e->record->key))
+ if ((ret = cb(c, pattern, e, userdata)))
+ return ret;
+ }
+
+ } else {
+ CattaCacheEntry *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(CattaCache *c, CattaKey *pattern, CattaCacheEntry *e, void *userdata) {
+ assert(c);
+ assert(pattern);
+ assert(e);
+
+ if (catta_record_equal_no_ttl(e->record, userdata))
+ return e;
+
+ return NULL;
+}
+
+static CattaCacheEntry *lookup_record(CattaCache *c, CattaRecord *r) {
+ assert(c);
+ assert(r);
+
+ return catta_cache_walk(c, r->key, lookup_record_callback, r);
+}
+
+static void next_expiry(CattaCache *c, CattaCacheEntry *e, unsigned percent);
+
+static void elapse_func(CattaTimeEvent *t, void *userdata) {
+ CattaCacheEntry *e = userdata;
+/* char *txt; */
+ unsigned percent = 0;
+
+ assert(t);
+ assert(e);
+
+/* txt = catta_record_to_string(e->record); */
+
+ switch (e->state) {
+
+ case CATTA_CACHE_EXPIRY_FINAL:
+ case CATTA_CACHE_POOF_FINAL:
+ case CATTA_CACHE_GOODBYE_FINAL:
+ case CATTA_CACHE_REPLACE_FINAL:
+
+ remove_entry(e->cache, e);
+
+ e = NULL;
+/* catta_log_debug("Removing entry from cache due to expiration (%s)", txt); */
+ break;
+
+ case CATTA_CACHE_VALID:
+ case CATTA_CACHE_POOF:
+ e->state = CATTA_CACHE_EXPIRY1;
+ percent = 85;
+ break;
+
+ case CATTA_CACHE_EXPIRY1:
+ e->state = CATTA_CACHE_EXPIRY2;
+ percent = 90;
+ break;
+ case CATTA_CACHE_EXPIRY2:
+ e->state = CATTA_CACHE_EXPIRY3;
+ percent = 95;
+ break;
+
+ case CATTA_CACHE_EXPIRY3:
+ e->state = CATTA_CACHE_EXPIRY_FINAL;
+ percent = 100;
+ break;
+ }
+
+ if (e) {
+
+ assert(percent > 0);
+
+ /* Request a cache update if we are subscribed to this entry */
+ if (catta_querier_shall_refresh_cache(e->cache->iface, e->record->key))
+ catta_interface_post_query(e->cache->iface, e->record->key, 0, NULL);
+
+ /* Check again later */
+ next_expiry(e->cache, e, percent);
+
+ }
+
+/* catta_free(txt); */
+}
+
+static void update_time_event(CattaCache *c, CattaCacheEntry *e) {
+ assert(c);
+ assert(e);
+
+ if (e->time_event)
+ catta_time_event_update(e->time_event, &e->expiry);
+ else
+ e->time_event = catta_time_event_new(c->server->time_event_queue, &e->expiry, elapse_func, e);
+}
+
+static void next_expiry(CattaCache *c, CattaCacheEntry *e, unsigned percent) {
+ CattaUsec usec, left, right;
+ time_t now;
+
+ assert(c);
+ assert(e);
+ assert(percent > 0 && percent <= 100);
+
+ usec = (CattaUsec) 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 + (CattaUsec) ((double) (right-left) * c->last_rand / (RAND_MAX+1.0));
+
+ e->expiry = e->timestamp;
+ catta_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(CattaCache *c, CattaCacheEntry *e, CattaCacheEntryState state) {
+ assert(c);
+ assert(e);
+
+ e->state = state;
+ gettimeofday(&e->expiry, NULL);
+ catta_timeval_add(&e->expiry, 1000000); /* 1s */
+ update_time_event(c, e);
+}
+
+void catta_cache_update(CattaCache *c, CattaRecord *r, int cache_flush, const CattaAddress *a) {
+/* char *txt; */
+
+ assert(c);
+ assert(r && r->ref >= 1);
+
+/* txt = catta_record_to_string(r); */
+
+ if (r->ttl == 0) {
+ /* This is a goodbye request */
+
+ CattaCacheEntry *e;
+
+ if ((e = lookup_record(c, r)))
+ expire_in_one_second(c, e, CATTA_CACHE_GOODBYE_FINAL);
+
+ } else {
+ CattaCacheEntry *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) {
+ CattaUsec t;
+
+ t = catta_timeval_diff(&now, &e->timestamp);
+
+ if (t > 1000000)
+ expire_in_one_second(c, e, CATTA_CACHE_REPLACE_FINAL);
+ }
+ }
+
+ /* Look for exactly the same entry */
+ for (e = first; e; e = e->by_key_next)
+ if (catta_record_equal_no_ttl(e->record, r))
+ break;
+ }
+
+ if (e) {
+
+/* catta_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)
+ catta_hashmap_replace(c->hashmap, r->key, e);
+
+ /* Update the record */
+ catta_record_unref(e->record);
+ e->record = catta_record_ref(r);
+
+/* catta_log_debug("cache: updating %s", txt); */
+
+ } else {
+ /* No entry found, therefore we create a new one */
+
+/* catta_log_debug("cache: couldn't find matching cache entry for %s", txt); */
+
+ if (c->n_entries >= c->server->config.n_cache_entries_max)
+ return;
+
+ if (!(e = catta_new(CattaCacheEntry, 1))) {
+ catta_log_error(__FILE__": Out of memory");
+ return;
+ }
+
+ e->cache = c;
+ e->time_event = NULL;
+ e->record = catta_record_ref(r);
+
+ /* Append to hash table */
+ CATTA_LLIST_PREPEND(CattaCacheEntry, by_key, first, e);
+ catta_hashmap_replace(c->hashmap, e->record->key, first);
+
+ /* Append to linked list */
+ CATTA_LLIST_PREPEND(CattaCacheEntry, entry, c->entries, e);
+
+ c->n_entries++;
+
+ /* Notify subscribers */
+ catta_multicast_lookup_engine_notify(c->server->multicast_lookup_engine, c->iface, e->record, CATTA_BROWSER_NEW);
+ }
+
+ e->origin = *a;
+ e->timestamp = now;
+ next_expiry(c, e, 80);
+ e->state = CATTA_CACHE_VALID;
+ e->cache_flush = cache_flush;
+ }
+
+/* catta_free(txt); */
+}
+
+struct dump_data {
+ CattaDumpCallback callback;
+ void* userdata;
+};
+
+static void dump_callback(void* key, void* data, void* userdata) {
+ CattaCacheEntry *e = data;
+ CattaKey *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 = catta_record_to_string(e->record)))
+ continue; /* OOM */
+
+ dump_data->callback(t, dump_data->userdata);
+ catta_free(t);
+ }
+}
+
+int catta_cache_dump(CattaCache *c, CattaDumpCallback callback, void* userdata) {
+ struct dump_data data;
+
+ assert(c);
+ assert(callback);
+
+ callback(";;; CACHE DUMP FOLLOWS ;;;", userdata);
+
+ data.callback = callback;
+ data.userdata = userdata;
+
+ catta_hashmap_foreach(c->hashmap, dump_callback, &data);
+
+ return 0;
+}
+
+int catta_cache_entry_half_ttl(CattaCache *c, CattaCacheEntry *e) {
+ struct timeval now;
+ unsigned age;
+
+ assert(c);
+ assert(e);
+
+ gettimeofday(&now, NULL);
+
+ age = (unsigned) (catta_timeval_diff(&now, &e->timestamp)/1000000);
+
+/* catta_log_debug("age: %lli, ttl/2: %u", age, e->record->ttl); */
+
+ return age >= e->record->ttl/2;
+}
+
+void catta_cache_flush(CattaCache *c) {
+ assert(c);
+
+ while (c->entries)
+ remove_entry(c, c->entries);
+}
+
+/*** Passive observation of failure ***/
+
+static void* start_poof_callback(CattaCache *c, CattaKey *pattern, CattaCacheEntry *e, void *userdata) {
+ CattaAddress *a = userdata;
+ struct timeval now;
+
+ assert(c);
+ assert(pattern);
+ assert(e);
+ assert(a);
+
+ gettimeofday(&now, NULL);
+
+ switch (e->state) {
+ case CATTA_CACHE_VALID:
+
+ /* The entry was perfectly valid till, now, so let's enter
+ * POOF mode */
+
+ e->state = CATTA_CACHE_POOF;
+ e->poof_address = *a;
+ e->poof_timestamp = now;
+ e->poof_num = 0;
+
+ break;
+
+ case CATTA_CACHE_POOF:
+ if (catta_timeval_diff(&now, &e->poof_timestamp) < 1000000)
+ break;
+
+ e->poof_timestamp = now;
+ e->poof_address = *a;
+ e->poof_num ++;
+
+ /* This is the 4th time we got no response, so let's
+ * fucking remove this entry. */
+ if (e->poof_num > 3)
+ expire_in_one_second(c, e, CATTA_CACHE_POOF_FINAL);
+ break;
+
+ default:
+ ;
+ }
+
+ return NULL;
+}
+
+void catta_cache_start_poof(CattaCache *c, CattaKey *key, const CattaAddress *a) {
+ assert(c);
+ assert(key);
+
+ catta_cache_walk(c, key, start_poof_callback, (void*) a);
+}
+
+void catta_cache_stop_poof(CattaCache *c, CattaRecord *record, const CattaAddress *a) {
+ CattaCacheEntry *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 == CATTA_CACHE_POOF || e->state == CATTA_CACHE_POOF_FINAL)
+ if (catta_address_cmp(a, &e->poof_address) == 0) {
+ e->state = CATTA_CACHE_VALID;
+ next_expiry(c, e, 80);
+ }
+}
projects / catta / blobdiff