netfilter: xt_physdev: unfold two loops in physdev_mt()
xt_physdev netfilter module can use an ifname_compare() helper
so that two loops are unfolded.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/netfilter/xt_physdev.c b/net/netfilter/xt_physdev.c
index 4b13ef7..44a234e 100644
--- a/net/netfilter/xt_physdev.c
+++ b/net/netfilter/xt_physdev.c
@@ -20,10 +20,27 @@
MODULE_ALIAS("ipt_physdev");
MODULE_ALIAS("ip6t_physdev");
+static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
+{
+ const unsigned long *a = (const unsigned long *)_a;
+ const unsigned long *b = (const unsigned long *)_b;
+ const unsigned long *mask = (const unsigned long *)_mask;
+ unsigned long ret;
+
+ ret = (a[0] ^ b[0]) & mask[0];
+ if (IFNAMSIZ > sizeof(unsigned long))
+ ret |= (a[1] ^ b[1]) & mask[1];
+ if (IFNAMSIZ > 2 * sizeof(unsigned long))
+ ret |= (a[2] ^ b[2]) & mask[2];
+ if (IFNAMSIZ > 3 * sizeof(unsigned long))
+ ret |= (a[3] ^ b[3]) & mask[3];
+ BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long));
+ return ret;
+}
+
static bool
physdev_mt(const struct sk_buff *skb, const struct xt_match_param *par)
{
- int i;
static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
const struct xt_physdev_info *info = par->matchinfo;
unsigned long ret;
@@ -68,11 +85,7 @@
if (!(info->bitmask & XT_PHYSDEV_OP_IN))
goto match_outdev;
indev = nf_bridge->physindev ? nf_bridge->physindev->name : nulldevname;
- for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned long); i++) {
- ret |= (((const unsigned long *)indev)[i]
- ^ ((const unsigned long *)info->physindev)[i])
- & ((const unsigned long *)info->in_mask)[i];
- }
+ ret = ifname_compare(indev, info->physindev, info->in_mask);
if (!ret ^ !(info->invert & XT_PHYSDEV_OP_IN))
return false;
@@ -82,11 +95,8 @@
return true;
outdev = nf_bridge->physoutdev ?
nf_bridge->physoutdev->name : nulldevname;
- for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned long); i++) {
- ret |= (((const unsigned long *)outdev)[i]
- ^ ((const unsigned long *)info->physoutdev)[i])
- & ((const unsigned long *)info->out_mask)[i];
- }
+ ret = ifname_compare(outdev, info->physoutdev, info->out_mask);
+
return (!!ret ^ !(info->invert & XT_PHYSDEV_OP_OUT));
}