Commit 323dbf96 authored by Eric Dumazet's avatar Eric Dumazet Committed by Patrick McHardy
Browse files

netfilter: ip6_tables: unfold two loops in ip6_packet_match() 



ip6_tables 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 eacc17fb

net/ipv6/netfilter/ip6_tables.c

+21 −12
Original line number Diff line number Diff line
@@ -89,6 +89,25 @@ ip6t_ext_hdr(u8 nexthdr) 
		 (nexthdr == IPPROTO_DSTOPTS) );

}



static unsigned long ifname_compare(const char *_a, const char *_b,

				    const unsigned 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;

}



/* Returns whether matches rule or not. */

/* Performance critical - called for every packet */

static inline bool
@@ -99,7 +118,6 @@ ip6_packet_match(const struct sk_buff *skb, 
		 unsigned int *protoff,

		 int *fragoff, bool *hotdrop)

{

	size_t i;

	unsigned long ret;

	const struct ipv6hdr *ipv6 = ipv6_hdr(skb);
@@ -120,12 +138,7 @@ ip6_packet_match(const struct sk_buff *skb, 
		return false;

	}



	/* Look for ifname matches; this should unroll nicely. */

	for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned long); i++) {

		ret |= (((const unsigned long *)indev)[i]

			^ ((const unsigned long *)ip6info->iniface)[i])

			& ((const unsigned long *)ip6info->iniface_mask)[i];

	}

	ret = ifname_compare(indev, ip6info->iniface, ip6info->iniface_mask);



	if (FWINV(ret != 0, IP6T_INV_VIA_IN)) {

		dprintf("VIA in mismatch (%s vs %s).%s\n",
@@ -134,11 +147,7 @@ ip6_packet_match(const struct sk_buff *skb, 
		return false;

	}



	for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned long); i++) {

		ret |= (((const unsigned long *)outdev)[i]

			^ ((const unsigned long *)ip6info->outiface)[i])

			& ((const unsigned long *)ip6info->outiface_mask)[i];

	}

	ret = ifname_compare(outdev, ip6info->outiface, ip6info->outiface_mask);



	if (FWINV(ret != 0, IP6T_INV_VIA_OUT)) {

		dprintf("VIA out mismatch (%s vs %s).%s\n",