From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: Re: Possible nftables U32 equivalent to read packet's data contents Date: Mon, 4 Sep 2017 22:55:21 +0200 Message-ID: <20170904205521.GA14891@salvia> References: <20170901103004.GA16773@salvia> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: Sender: netfilter-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Raul Martinez Cc: "netfilter@vger.kernel.org" Hi Raul, On Fri, Sep 01, 2017 at 04:39:35PM +0000, Raul Martinez wrote: > Hi Pablo, > > Ultimately my use would be to read the first byte of a ESP IP > packet's data payload. So IP layer is where I would want the > expression to work in. > > The packets I am working with are identical and need to be > routed to one of two interfaces based on if the first byte of > the data contents is non-zero. OK, so it's just an arbitrary byte. Not anything in a standard header that needs to be matched. I'm asking because we could add the protocol definition for what you need, so we don't need to use raw expressions.