diff options
| -rw-r--r-- | net/ipv4/netfilter/arp_tables.c | 44 |
1 files changed, 34 insertions, 10 deletions
diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index 7ea88b61cb0..b5db4634261 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -73,6 +73,36 @@ static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap, return (ret != 0); } +/* + * Unfortunatly, _b and _mask are not aligned to an int (or long int) + * Some arches dont care, unrolling the loop is a win on them. + */ +static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask) +{ +#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS + 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)); +#else + unsigned long ret = 0; + int i; + + for (i = 0; i < IFNAMSIZ; i++) + ret |= (_a[i] ^ _b[i]) & _mask[i]; +#endif + return ret; +} + /* Returns whether packet matches rule or not. */ static inline int arp_packet_match(const struct arphdr *arphdr, struct net_device *dev, @@ -83,7 +113,7 @@ static inline int arp_packet_match(const struct arphdr *arphdr, const char *arpptr = (char *)(arphdr + 1); const char *src_devaddr, *tgt_devaddr; __be32 src_ipaddr, tgt_ipaddr; - int i, ret; + long ret; #define FWINV(bool, invflg) ((bool) ^ !!(arpinfo->invflags & (invflg))) @@ -156,10 +186,7 @@ static inline int arp_packet_match(const struct arphdr *arphdr, } /* Look for ifname matches. */ - for (i = 0, ret = 0; i < IFNAMSIZ; i++) { - ret |= (indev[i] ^ arpinfo->iniface[i]) - & arpinfo->iniface_mask[i]; - } + ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask); if (FWINV(ret != 0, ARPT_INV_VIA_IN)) { dprintf("VIA in mismatch (%s vs %s).%s\n", @@ -168,10 +195,7 @@ static inline int arp_packet_match(const struct arphdr *arphdr, return 0; } - for (i = 0, ret = 0; i < IFNAMSIZ; i++) { - ret |= (outdev[i] ^ arpinfo->outiface[i]) - & arpinfo->outiface_mask[i]; - } + ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask); if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) { dprintf("VIA out mismatch (%s vs %s).%s\n", @@ -221,7 +245,7 @@ unsigned int arpt_do_table(struct sk_buff *skb, const struct net_device *out, struct xt_table *table) { - static const char nulldevname[IFNAMSIZ]; + static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long)))); unsigned int verdict = NF_DROP; const struct arphdr *arp; bool hotdrop = false; |