Re: ipv4: Simplify ARP hash function.

From: David Miller <davem@davemloft.net>
Date: Fri, 08 Jul 2011 12:51:18 -0700 (PDT)

From: Michał Mirosław <redacted>
Date: Fri, 8 Jul 2011 21:39:18 +0200

quoted

With b[3] = b[0] ^ b[1] ^ b[2] you get 2^24 keys that hash to the same bucket.

Ok, I'm convinced, thanks :-)

Although, actually it's not this simple.  The attack doesn't work.

As they "attack" us, the ARP hash table grows and thus the hash mask
changes to match.  Then his old collisions won't collide any more.

We could even adjust the fold shifts as the table grows to make this
effect even more pronounced.