src: rework of the hash-cache infrastructure

Currently, the caching system is implemented in a two layer
architecture: hashtable (inner layer) and cache (upper layer).
This patch reworks the hash-cache infrastructure to solve some
initial design problems to make it more flexible, the main strong
points of this patch are:

* Memory handling is done in the cache layer, not in the inner
hashtable layer. This removes one of the main dependencies between
the hashtable and the cache classes.
* Remove excessive encapsulation: the former cache used to hide a
lot of details of the inner hashtable implementation.
* Fix over-hashing of some operations: lookup-delete-add required
three hash calculations. Similarly, the update-or-add operation
required two hash calculations. Now, we calculate the hash once
and re-use the value how many times as we need.

This patch simplifies the caching system. As a result, we save ~130
lines of code. Small code means and less complexity means less
chance to have bugs.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 13 insertions, 14 deletions

diff --git a/src/sync-alarm.c b/src/sync-alarm.c
index d871b75..34937fe 100644
--- a/src/sync-alarm.c
+++ b/src/sync-alarm.c
@@ -19,7 +19,6 @@
 #include "conntrackd.h"
 #include "sync.h"
 #include "network.h"
-#include "us-conntrack.h"
 #include "alarm.h"
 #include "cache.h"
 #include "debug.h"
@@ -30,40 +29,40 @@
 static void refresher(struct alarm_block *a, void *data)
 {
 	struct nethdr *net;
-	struct us_conntrack *u = data;
+	struct cache_object *obj = data;
 
-	debug_ct(u->ct, "persistence update");
+	debug_ct(obj->ct, "persistence update");
 
 	add_alarm(a, 
 		  random() % CONFIG(refresh) + 1,
 		  ((random() % 5 + 1)  * 200000) - 1);
 
-	net = BUILD_NETMSG(u->ct, NET_T_STATE_UPD);
+	net = BUILD_NETMSG(obj->ct, NET_T_STATE_UPD);
 	mcast_buffered_send_netmsg(STATE_SYNC(mcast_client), net);
 }
 
-static void cache_alarm_add(struct us_conntrack *u, void *data)
+static void cache_alarm_add(struct cache_object *obj, void *data)
 {
-	struct alarm_block *alarm = data;
+	struct alarm_block *a = data;
 
-	init_alarm(alarm, u, refresher);
-	add_alarm(alarm,
+	init_alarm(a, obj, refresher);
+	add_alarm(a,
 		  random() % CONFIG(refresh) + 1,
 		  ((random() % 5 + 1)  * 200000) - 1);
 }
 
-static void cache_alarm_update(struct us_conntrack *u, void *data)
+static void cache_alarm_update(struct cache_object *obj, void *data)
 {
-	struct alarm_block *alarm = data;
-	add_alarm(alarm, 
+	struct alarm_block *a = data;
+	add_alarm(a, 
 		  random() % CONFIG(refresh) + 1,
 		  ((random() % 5 + 1)  * 200000) - 1);
 }
 
-static void cache_alarm_destroy(struct us_conntrack *u, void *data)
+static void cache_alarm_destroy(struct cache_object *obj, void *data)
 {
-	struct alarm_block *alarm = data;
-	del_alarm(alarm);
+	struct alarm_block *a = data;
+	del_alarm(a);
 }
 
 static struct cache_extra cache_alarm_extra = {