Commit eacc17fb authored by Eric Dumazet's avatar Eric Dumazet Committed by Patrick McHardy
Browse files

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: default avatarEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
parent 4323362e

net/netfilter/xt_physdev.c

+21 −11
Original line number Diff line number Diff line
@@ -20,10 +20,27 @@ MODULE_DESCRIPTION("Xtables: Bridge physical device match"); 
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 @@ physdev_mt(const struct sk_buff *skb, const struct xt_match_param *par) 
	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 @@ physdev_mt(const struct sk_buff *skb, const struct xt_match_param *par) 
		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));

}