From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: arp_hash Date: Sun, 22 Mar 2015 12:54:58 -0400 (EDT) Message-ID: <20150322.125458.2054837991708165397.davem@davemloft.net> References: <20150322114204.GA5010@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, roland@purestorage.com To: herbert@gondor.apana.org.au Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:47390 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751626AbbCVQzD (ORCPT ); Sun, 22 Mar 2015 12:55:03 -0400 In-Reply-To: <20150322114204.GA5010@gondor.apana.org.au> Sender: netdev-owner@vger.kernel.org List-ID: From: Herbert Xu Date: Sun, 22 Mar 2015 22:42:04 +1100 > If the attacker can somehow get the pointer value of the device > then all is lost since they could set any number of the low bits > of val to zero. This "attacker" with access to your physcial network? I'm all for shifting the device pointer down a few bits to get more entropy, but I don't completely agree with the rest of your objections. This hash function has to be as fast as possible, even jhash{,2} is too expensive.