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-rw-r--r--include/linux/etherdevice.h42
-rw-r--r--net/ethernet/eth.c6
2 files changed, 45 insertions, 3 deletions
diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
index 0e5e97060034..1cb0f0b90926 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 a87a171d9914..280352aba403 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;
}