From owner-svn-src-all@FreeBSD.ORG Thu Apr 2 18:36:52 2015 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 22145DD0; Thu, 2 Apr 2015 18:36:52 +0000 (UTC) Received: from mail.turbocat.net (mail.turbocat.net [IPv6:2a01:4f8:d16:4514::2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id CB1ACF1D; Thu, 2 Apr 2015 18:36:51 +0000 (UTC) Received: from laptop015.home.selasky.org (cm-176.74.213.204.customer.telag.net [176.74.213.204]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.turbocat.net (Postfix) with ESMTPSA id 862F81FE022; Thu, 2 Apr 2015 20:36:49 +0200 (CEST) Message-ID: <551D8C6C.9060504@selasky.org> Date: Thu, 02 Apr 2015 20:37:32 +0200 From: Hans Petter Selasky User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: "Robert N. M. Watson" Subject: Re: svn commit: r280971 - in head: contrib/ipfilter/tools share/man/man4 sys/contrib/ipfilter/netinet sys/netinet sys/netipsec sys/netpfil/pf References: <201504012226.t31MQedN044443@svn.freebsd.org> <1427929676.82583.103.camel@freebsd.org> <20150402123522.GC64665@FreeBSD.org> <20150402133751.GA549@dft-labs.eu> <20150402134217.GG64665@FreeBSD.org> <20150402135157.GB549@dft-labs.eu> <1427983109.82583.115.camel@freebsd.org> <20150402142318.GC549@dft-labs.eu> <20150402143420.GI64665@FreeBSD.org> <20150402153805.GD549@dft-labs.eu> <551D8143.4060509@selasky.org> <551D8945.8050906@selasky.org> <8900318B-8155-4131-A0C3-3DE169782EFC@FreeBSD.org> In-Reply-To: <8900318B-8155-4131-A0C3-3DE169782EFC@FreeBSD.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: Mateusz Guzik , Ian Lepore , svn-src-all@freebsd.org, src-committers@freebsd.org, Gleb Smirnoff , svn-src-head@freebsd.org X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 02 Apr 2015 18:36:52 -0000 Hi Robert, On 04/02/15 20:32, Robert N. M. Watson wrote: > On 2 Apr 2015, at 19:24, Hans Petter Selasky wrote: > >> In my sketchup I assume that packets for the same destination will not be re-ordered. I see that the current ip_reass() code does not care about TCP or UDP port numbers at all. Maybe we should add code to check that the packet belongs to the same ports too? > > Higher-level network headers will appear only in the first fragment, so can't be used in matching later fragments. Right. > >> Does somebody here know what happens in these two cases: >> >> If we are transmitting using TSO, will the network adapter increment the IP ID field somehow? What happens if an outgoing IP packet resulting from a TSO packet get fragmented by a router? > > Quite possibly -- this is presumably specified by the NIC vendor, but it would be good to do a bit of a survey and see what happens in practice. > >> In ip_fragment() when we create fragments we should increment the ip_id value for each fragment? > I'm asking because the code in FreeBSD, since the beginning probably, just copies the IP header, and use the same IP ID for all the fragments ! This just hit my mind after some recent work in this area. > > That you are asking this question while hacking on the IP ID code is deeply troubling. > Please go read up on how IP fragmentation works before going any further with these changes! I see from ip_reass() how it works. --HPS