diff options
| -rw-r--r-- | include/linux/etherdevice.h | 42 | ||||
| -rw-r--r-- | net/ethernet/eth.c | 6 |
2 files changed, 45 insertions, 3 deletions
diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h index 0e5e970..1cb0f0b 100644 --- a/include/linux/etherdevice.h +++ b/include/linux/etherdevice.h @@ -27,6 +27,7 @@ #include <linux/if_ether.h> #include <linux/netdevice.h> #include <linux/random.h> +#include <asm/unaligned.h> #ifdef __KERNEL__ extern __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev); @@ -140,6 +141,47 @@ static inline unsigned compare_ether_addr(const u8 *addr1, const u8 *addr2) BUILD_BUG_ON(ETH_ALEN != 6); return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | (a[2] ^ b[2])) != 0; } + +static inline unsigned long zap_last_2bytes(unsigned long value) +{ +#ifdef __BIG_ENDIAN + return value >> 16; +#else + return value << 16; +#endif +} + +/** + * compare_ether_addr_64bits - Compare two Ethernet addresses + * @addr1: Pointer to an array of 8 bytes + * @addr2: Pointer to an other array of 8 bytes + * + * Compare two ethernet addresses, returns 0 if equal. + * Same result than "memcmp(addr1, addr2, ETH_ALEN)" but without conditional + * branches, and possibly long word memory accesses on CPU allowing cheap + * unaligned memory reads. + * arrays = { byte1, byte2, byte3, byte4, byte6, byte7, pad1, pad2} + * + * Please note that alignment of addr1 & addr2 is only guaranted to be 16 bits. + */ + +static inline unsigned compare_ether_addr_64bits(const u8 addr1[6+2], + const u8 addr2[6+2]) +{ +#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS + unsigned long fold = ((*(unsigned long *)addr1) ^ + (*(unsigned long *)addr2)); + + if (sizeof(fold) == 8) + return zap_last_2bytes(fold) != 0; + + fold |= zap_last_2bytes((*(unsigned long *)(addr1 + 4)) ^ + (*(unsigned long *)(addr2 + 4))); + return fold != 0; +#else + return compare_ether_addr(addr1, addr2); +#endif +} #endif /* __KERNEL__ */ #endif /* _LINUX_ETHERDEVICE_H */ diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c index a87a171..280352a 100644 --- a/net/ethernet/eth.c +++ b/net/ethernet/eth.c @@ -165,8 +165,8 @@ __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev) skb_pull(skb, ETH_HLEN); eth = eth_hdr(skb); - if (is_multicast_ether_addr(eth->h_dest)) { - if (!compare_ether_addr(eth->h_dest, dev->broadcast)) + if (unlikely(is_multicast_ether_addr(eth->h_dest))) { + if (!compare_ether_addr_64bits(eth->h_dest, dev->broadcast)) skb->pkt_type = PACKET_BROADCAST; else skb->pkt_type = PACKET_MULTICAST; @@ -181,7 +181,7 @@ __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev) */ else if (1 /*dev->flags&IFF_PROMISC */ ) { - if (unlikely(compare_ether_addr(eth->h_dest, dev->dev_addr))) + if (unlikely(compare_ether_addr_64bits(eth->h_dest, dev->dev_addr))) skb->pkt_type = PACKET_OTHERHOST; } |
