Commit f2ad1c0a authored by Stephen Hemminger's avatar Stephen Hemminger Committed by David S. Miller

[TOKENRING]: better hash function.

Rather than a simple for loop sum, use a better hash function
for the mac address.

Function repurposed from Lennert's bridge code.
parent 8154b249
......@@ -78,6 +78,22 @@ static struct timer_list rif_timer;
int sysctl_tr_rif_timeout = RIF_TIMEOUT;
static inline unsigned long rif_hash(const unsigned char *addr)
{
unsigned long x;
x = addr[0];
x = (x << 2) ^ addr[1];
x = (x << 2) ^ addr[2];
x = (x << 2) ^ addr[3];
x = (x << 2) ^ addr[4];
x = (x << 2) ^ addr[5];
x ^= x >> 8;
return x & (RIF_TABLE_SIZE - 1);
}
/*
* Put the headers on a token ring packet. Token ring source routing
* makes this a little more exciting than on ethernet.
......@@ -231,7 +247,7 @@ unsigned short tr_type_trans(struct sk_buff *skb, struct net_device *dev)
void tr_source_route(struct sk_buff *skb,struct trh_hdr *trh,struct net_device *dev)
{
int i, slack;
int slack;
unsigned int hash;
struct rif_cache_s *entry;
unsigned char *olddata;
......@@ -252,8 +268,7 @@ void tr_source_route(struct sk_buff *skb,struct trh_hdr *trh,struct net_device *
}
else
{
for(i=0,hash=0;i<TR_ALEN;hash+=trh->daddr[i++]);
hash&=RIF_TABLE_SIZE-1;
hash = rif_hash(trh->daddr);
/*
* Walk the hash table and look for an entry
*/
......@@ -321,7 +336,6 @@ printk("source routing for %02X:%02X:%02X:%02X:%02X:%02X\n",trh->daddr[0],
static void tr_add_rif_info(struct trh_hdr *trh, struct net_device *dev)
{
int i;
unsigned int hash, rii_p = 0;
struct rif_cache_s *entry;
......@@ -341,8 +355,7 @@ static void tr_add_rif_info(struct trh_hdr *trh, struct net_device *dev)
}
}
for(i=0,hash=0;i<TR_ALEN;hash+=trh->saddr[i++]);
hash&=RIF_TABLE_SIZE-1;
hash = rif_hash(trh->saddr);
for(entry=rif_table[hash];entry && memcmp(&(entry->addr[0]),&(trh->saddr[0]),TR_ALEN);entry=entry->next);
if(entry==NULL)
......
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