From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thiago Macieira Subject: Re: [PATCH net] datagram: When peeking datagrams with offset < 0 don't skip empty skbs Date: Mon, 14 Aug 2017 09:06:35 -0700 Message-ID: <2828157.5Eig1SAfYW@tjmaciei-mobl1> References: <20170814055259.31078-1-matthew@mjdsystems.ca> <1846443.VTclhqQinN@ring00> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: Matthew Dawson , Paolo Abeni , Network Development To: Willem de Bruijn Return-path: Received: from mga09.intel.com ([134.134.136.24]:33902 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752150AbdHNQHG (ORCPT ); Mon, 14 Aug 2017 12:07:06 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Monday, 14 August 2017 08:03:50 PDT Willem de Bruijn wrote: > > I'm actually surprised that only unix sockets can have negative values. > > Is > > there a reason for that? I had assumed that sk_set_peek_off would allow > > negative values as the code already has to support negative values due to > > what the initial value is. > > A negative initial value indicates that PEEK_OFF is disabled. It only > makes sense to peek from a positive offset from the start of the data. But here's a question: if the peek offset is equal to the length, should the reading return an empty datagram? This would indicate to the caller that there was a datagram there, which was skipped over. That's how we deal with empty datagrams anyway. -- Thiago Macieira - thiago.macieira (AT) intel.com Software Architect - Intel Open Source Technology Center