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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>
This commit is contained in:
Eric Dumazet 2009-02-19 11:17:17 +01:00 committed by Patrick McHardy
parent 4323362e49
commit eacc17fb64
1 changed files with 21 additions and 11 deletions
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32
net/netfilter/xt_physdev.c
View File

@ -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 @@ match_outdev:
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));
}