[NET]: Slightly optimize ethernet address comparison.
We know the thing is at least 2-byte aligned, so take advantage of that instead of invoking memcmp() which results in truly horrifically inefficient code because it can't assume anything about alignment. Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -146,6 +146,19 @@ int eth_rebuild_header(struct sk_buff *skb)
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return 0;
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return 0;
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}
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}
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static inline unsigned int compare_eth_addr(const unsigned char *__a, const unsigned char *__b)
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{
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const unsigned short *dest = (unsigned short *) __a;
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const unsigned short *devaddr = (unsigned short *) __b;
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unsigned int res;
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BUILD_BUG_ON(ETH_ALEN != 6);
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res = ((dest[0] ^ devaddr[0]) |
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(dest[1] ^ devaddr[1]) |
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(dest[2] ^ devaddr[2])) != 0;
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return res;
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}
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/*
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/*
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* Determine the packet's protocol ID. The rule here is that we
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* Determine the packet's protocol ID. The rule here is that we
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@ -158,16 +171,15 @@ __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
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struct ethhdr *eth;
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struct ethhdr *eth;
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unsigned char *rawp;
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unsigned char *rawp;
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skb->mac.raw=skb->data;
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skb->mac.raw = skb->data;
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skb_pull(skb,ETH_HLEN);
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skb_pull(skb,ETH_HLEN);
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eth = eth_hdr(skb);
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eth = eth_hdr(skb);
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if(*eth->h_dest&1)
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if (*eth->h_dest&1) {
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{
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if (!compare_eth_addr(eth->h_dest, dev->broadcast))
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if(memcmp(eth->h_dest,dev->broadcast, ETH_ALEN)==0)
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skb->pkt_type = PACKET_BROADCAST;
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skb->pkt_type=PACKET_BROADCAST;
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else
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else
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skb->pkt_type=PACKET_MULTICAST;
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skb->pkt_type = PACKET_MULTICAST;
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}
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}
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/*
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/*
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@ -178,10 +190,9 @@ __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
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* seems to set IFF_PROMISC.
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* seems to set IFF_PROMISC.
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*/
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*/
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else if(1 /*dev->flags&IFF_PROMISC*/)
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else if(1 /*dev->flags&IFF_PROMISC*/) {
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{
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if (unlikely(!compare_eth_addr(eth->h_dest, dev->dev_addr)))
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if(memcmp(eth->h_dest,dev->dev_addr, ETH_ALEN))
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skb->pkt_type = PACKET_OTHERHOST;
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skb->pkt_type=PACKET_OTHERHOST;
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}
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}
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if (ntohs(eth->h_proto) >= 1536)
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if (ntohs(eth->h_proto) >= 1536)
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