netfilter: xtables: use memcmp in unconditional check
Instead of inspecting each u32/char open-coded, clean up and make use
of memcmp. On some arches, memcmp is implemented as assembly or GCC's
__builtin_memcmp which can possibly take advantages of known
alignment.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index ced1f2c..1389ad9 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -222,16 +222,11 @@
/* All zeroes == unconditional rule. */
/* Mildly perf critical (only if packet tracing is on) */
-static inline int
-unconditional(const struct ip6t_ip6 *ipv6)
+static inline bool unconditional(const struct ip6t_ip6 *ipv6)
{
- unsigned int i;
+ static const struct ip6t_ip6 uncond;
- for (i = 0; i < sizeof(*ipv6); i++)
- if (((char *)ipv6)[i])
- break;
-
- return (i == sizeof(*ipv6));
+ return memcmp(ipv6, &uncond, sizeof(uncond)) == 0;
}
#if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \