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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: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This commit is contained in:
Eric Dumazet 2009-02-19 11:18:23 +01:00 committed by Patrick McHardy
parent eacc17fb64
commit 323dbf9638
1 changed files with 21 additions and 12 deletions
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33
net/ipv6/netfilter/ip6_tables.c
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@ -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",