From owner-freebsd-net@FreeBSD.ORG  Sun May  4 14:27:55 2003
Return-Path: <owner-freebsd-net@FreeBSD.ORG>
Delivered-To: freebsd-net@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id BA35937B401
	for <net@freebsd.org>; Sun,  4 May 2003 14:27:55 -0700 (PDT)
Received: from pit.databus.com (p70-227.acedsl.com [66.114.70.227])
	by mx1.FreeBSD.org (Postfix) with ESMTP id ED6DA43F3F
	for <net@freebsd.org>; Sun,  4 May 2003 14:27:54 -0700 (PDT)
	(envelope-from barney@pit.databus.com)
Received: from pit.databus.com (localhost [127.0.0.1])
	by pit.databus.com (8.12.9/8.12.9) with ESMTP id h44LRsU0021473;
	Sun, 4 May 2003 17:27:54 -0400 (EDT)
	(envelope-from barney@pit.databus.com)
Received: (from barney@localhost)
	by pit.databus.com (8.12.9/8.12.9/Submit) id h44LRrBS021472;
	Sun, 4 May 2003 17:27:53 -0400 (EDT)
	(envelope-from barney)
Date: Sun, 4 May 2003 17:27:53 -0400
From: Barney Wolff <barney@pit.databus.com>
To: mark tinguely <tinguely@web.cs.ndsu.nodak.edu>
Message-ID: <20030504212753.GA21240@pit.databus.com>
References: <200305041750.h44HoBbo077630@web.cs.ndsu.nodak.edu>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <200305041750.h44HoBbo077630@web.cs.ndsu.nodak.edu>
User-Agent: Mutt/1.4.1i
X-Scanned-By: MIMEDefang 2.31 (www . roaringpenguin . com / mimedefang)
cc: net@freebsd.org
Subject: Re: Reducing ip_id information leakage
X-BeenThere: freebsd-net@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Networking and TCP/IP with FreeBSD <freebsd-net.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
	<mailto:freebsd-net-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-net>
List-Post: <mailto:freebsd-net@freebsd.org>
List-Help: <mailto:freebsd-net-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
	<mailto:freebsd-net-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sun, 04 May 2003 21:27:56 -0000

On Sun, May 04, 2003 at 12:50:11PM -0500, mark tinguely wrote:
> Less global (think per interface, or per source/destination/port as mentioned
> that is done in Solaris).

Nit: you can't use port, as that will not appear in the frags and you
can't afford collision.

If I were writing the code, I'd do a very fast hash on src/dst/proto
into say 8-10 bits, keep 256-1024 counters, and let it go at that.

-- 
Barney Wolff         http://www.databus.com/bwresume.pdf
I'm available by contract or FT, in the NYC metro area or via the 'Net.