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>
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index 2a7eb1d..aece6c2 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -209,6 +209,11 @@
}
}
mutex_unlock(&xt[af].mutex);
+
+ if (af != NFPROTO_UNSPEC)
+ /* Try searching again in the family-independent list */
+ return xt_find_match(NFPROTO_UNSPEC, name, revision);
+
return ERR_PTR(err);
}
EXPORT_SYMBOL(xt_find_match);
@@ -234,6 +239,11 @@
}
}
mutex_unlock(&xt[af].mutex);
+
+ if (af != NFPROTO_UNSPEC)
+ /* Try searching again in the family-independent list */
+ return xt_find_target(NFPROTO_UNSPEC, name, revision);
+
return ERR_PTR(err);
}
EXPORT_SYMBOL(xt_find_target);
