netfilter: implement NFPROTO_UNSPEC as a wildcard for extensions

When a match or target is looked up using xt_find_{match,target},
Xtables will also search the NFPROTO_UNSPEC module list. This allows
for protocol-independent extensions (like xt_time) to be reused from
other components (e.g. arptables, ebtables).

Extensions that take different codepaths depending on match->family
or target->family of course cannot use NFPROTO_UNSPEC within the
registration structure (e.g. xt_pkttype).

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 10 insertions, 21 deletions

diff --git a/net/netfilter/xt_statistic.c b/net/netfilter/xt_statistic.c
index fd3bb1400df..f41a92322e6 100644
--- a/net/netfilter/xt_statistic.c
+++ b/net/netfilter/xt_statistic.c
@@ -66,35 +66,24 @@ statistic_mt_check(const char *tablename, const void *entry,
 	return true;
 }
 
-static struct xt_match statistic_mt_reg[] __read_mostly = {
-	{
-		.name		= "statistic",
-		.family		= NFPROTO_IPV4,
-		.checkentry	= statistic_mt_check,
-		.match		= statistic_mt,
-		.matchsize	= sizeof(struct xt_statistic_info),
-		.me		= THIS_MODULE,
-	},
-	{
-		.name		= "statistic",
-		.family		= NFPROTO_IPV6,
-		.checkentry	= statistic_mt_check,
-		.match		= statistic_mt,
-		.matchsize	= sizeof(struct xt_statistic_info),
-		.me		= THIS_MODULE,
-	},
+static struct xt_match xt_statistic_mt_reg __read_mostly = {
+	.name       = "statistic",
+	.revision   = 0,
+	.family     = NFPROTO_UNSPEC,
+	.match      = statistic_mt,
+	.checkentry = statistic_mt_check,
+	.matchsize  = sizeof(struct xt_statistic_info),
+	.me         = THIS_MODULE,
 };
 
 static int __init statistic_mt_init(void)
 {
-	return xt_register_matches(statistic_mt_reg,
-	       ARRAY_SIZE(statistic_mt_reg));
+	return xt_register_match(&xt_statistic_mt_reg);
 }
 
 static void __exit statistic_mt_exit(void)
 {
-	xt_unregister_matches(statistic_mt_reg,
-	                      ARRAY_SIZE(statistic_mt_reg));
+	xt_unregister_match(&xt_statistic_mt_reg);
 }
 
 module_init(statistic_mt_init);