Date: Mon, 12 Jan 2015 14:54:21 -0500 From: John Baldwin <jhb@freebsd.org> To: "Bjoern A. Zeeb" <bz@freebsd.org> Cc: "src-committers@freebsd.org" <src-committers@freebsd.org>, John Nielsen <lists@jnielsen.net>, Bryan Venteicher <bryanv@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, Bryan Drewery <bdrewery@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org> Subject: Re: svn commit: r272886 - in head/sys: netinet netinet6 Message-ID: <9249494.lCU21bPJgC@ralph.baldwin.cx> In-Reply-To: <88ADFC71-FD44-4012-9814-1771D31646FF@FreeBSD.org> References: <201410100609.s9A690NU067686@svn.freebsd.org> <6173473.uE5Sr5nj0c@ralph.baldwin.cx> <88ADFC71-FD44-4012-9814-1771D31646FF@FreeBSD.org>
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On Monday, January 12, 2015 05:42:34 PM Bjoern A. Zeeb wrote: > > On 12 Jan 2015, at 15:51 , John Baldwin <john@baldwin.cx> wrote: > > > > On Tuesday, January 06, 2015 07:07:11 PM Bryan Venteicher wrote: > >> On Tue, Jan 6, 2015 at 5:27 PM, Bryan Drewery <bdrewery@freebsd.org> wrote: > >>> On 1/6/2015 4:00 PM, Bryan Venteicher wrote: > >>>> On Tue, Jan 6, 2015 at 2:52 PM, John Nielsen <lists@jnielsen.net > >>>> > >>>> <mailto:lists@jnielsen.net>> wrote: > >>>> Bryan- > >>>> > >>>> On Oct 10, 2014, at 12:09 AM, Bryan Venteicher <bryanv@freebsd.org > >>>>> > >>>> <mailto:bryanv@freebsd.org>> wrote: > >>>>> Author: bryanv > >>>>> Date: Fri Oct 10 06:08:59 2014 > >>>>> New Revision: 272886 > >>>>> URL: https://svnweb.freebsd.org/changeset/base/272886 > >>>>> > >>>>> Log: > >>>>> Add context pointer and source address to the UDP tunnel callback > >>>>> > >>>>> These are needed for the forthcoming vxlan implementation. The > >>> > >>> context > >>> > >>>>> pointer means we do not have to use a spare pointer field in the > >>> > >>> inpcb, > >>> > >>>>> and the source address is required to populate vxlan's forwarding > >>> > >>> table. > >>> > >>>>> While I highly doubt there is an out of tree consumer of the UDP > >>>>> tunneling callback, this change may be a difficult to eventually > >>> > >>> MFC. > >>> > >>>> I noticed this comment while doing an MFC of vxlan to my local tree. > >>>> Do you think an MFC to 10-STABLE of this change (and vxlan > >>>> generally) will be feasible? Is there precedent for ABI changes like > >>>> this being sanctioned? Could symbol versioning help? > >>>> > >>>> I'd like to get some consensus on whether this commit is OK to MFC. > >>>> With > >>>> this commit, vxlan should be an easy to MFC. > >>> > >>> Breaking ABI will potentially hurt packages. FreeBSD builds packages for > >>> the oldest supported release on a branch. If you break ABI in 10.2 while > >>> we are building packages for 10.1 then any packages using these > >>> interfaces may not work right or result in panics packages with kmods. > >>> Please consider that. > >> > >> The only user visible change of this commit would be the addition of a > >> field at the end of 'struct udpcb'. I don't think that is a problem, at > >> least a similar change didn't prevent the MFC of UDP Lite. > >> > >> The kernel part of this changes the UDP tunneling functions which I guess > >> there could be a 3rd party module out there, but I very highly doubt > >> that, > >> based on how un-useful the previous interface was. > > > > Userland should not be impacted by this at all. (Nothing in userland > > cares > > about udpcb's internals.) I think there was only ever one consumer for > > the > > existing UDP tunneling code (bz@ knows what it is). I'm not sure where it > > lives. > > If you are talking about u_tun_func then it came from SCTP over UDP > tunneling. tuexen and rrs are your friends. > > I was wondering if it could be used similarly for IPsec UDPencap but I think > that went nowhere back then. It is the IPsec UDPencap case I was thinking of. If that is a dead end then the only consumer is already in-tree, so in this case I think this is ok to MFC (but remember to bump __FreeBSD_version). -- John Baldwin
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