From eacc17fb64f03b6c268aaf6cea320100d19d8af5 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 19 Feb 2009 11:17:17 +0100 Subject: [PATCH] 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 Signed-off-by: Patrick McHardy --- net/netfilter/xt_physdev.c | 32 +++++++++++++++++++++----------- 1 file changed, 21 insertions(+), 11 deletions(-) diff --git a/net/netfilter/xt_physdev.c b/net/netfilter/xt_physdev.c index 4b13ef7ce145..44a234ef4439 100644 --- a/net/netfilter/xt_physdev.c +++ b/net/netfilter/xt_physdev.c @@ -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)); } -- 2.20.1