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Re: [Qemu-devel] [PATCH v4 4/5] slirp: VMStatify socket level
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH v4 4/5] slirp: VMStatify socket level |
Date: |
Tue, 28 Feb 2017 17:09:26 +0000 |
User-agent: |
Mutt/1.7.1 (2016-10-04) |
* Samuel Thibault (address@hidden) wrote:
> Dr. David Alan Gilbert, on mar. 28 févr. 2017 17:00:17 +0000, wrote:
> > * Samuel Thibault (address@hidden) wrote:
> > > Dr. David Alan Gilbert, on mar. 28 févr. 2017 16:54:46 +0000, wrote:
> > > > I'm thinking one way to do it without changing the version would
> > > > be to use the existing value for IPv4, and on reading allow any other
> > > > value for IPv6 (or just the ones we know about); that would make
> > > > it inwards migration compatible.
> > >
> > > Right. I don't know if that's enough for QEMU requirements.
> >
> > If you change the version number you break backwards migration anyway;
> > but doing what I suggested would keep backwards working in most cases.
>
> Sure, but in some cases we're breaking upward compatibility *silently*.
No, we don't need to break upwards compatibility; if I understand correctly
the only values that can be in that field at the moment are:
AF_INET - IPv4 which is 2 on everything we've seen
AF_INET6 - whose value is different on different implementations.
If we accept an incoming value of '2' to mean AF_INET then all existing
IPv4 connections work.
If we accept any other incoming value as AF_INET6 all existing IPv6 connections
work.
- so that's foward compatibility OK.
If we generate '2' as the outgoing value for AF_INET then migration
to all exiting code works for IPv4; so backwards works for IPv4.
If we generate Linux's AF_INET6 number then IPv6 also works backwards
but only for Linux.
Dave
> Samuel
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- Re: [Qemu-devel] [PATCH v4 4/5] slirp: VMStatify socket level, (continued)
- Re: [Qemu-devel] [PATCH v4 4/5] slirp: VMStatify socket level, Dr. David Alan Gilbert, 2017/02/21
- Re: [Qemu-devel] [PATCH v4 4/5] slirp: VMStatify socket level, Dr. David Alan Gilbert, 2017/02/23
- Re: [Qemu-devel] [PATCH v4 4/5] slirp: VMStatify socket level, Daniel P. Berrange, 2017/02/23
- Re: [Qemu-devel] [PATCH v4 4/5] slirp: VMStatify socket level, Dr. David Alan Gilbert, 2017/02/23
- Re: [Qemu-devel] [PATCH v4 4/5] slirp: VMStatify socket level, Samuel Thibault, 2017/02/26
- Re: [Qemu-devel] [PATCH v4 4/5] slirp: VMStatify socket level, Samuel Thibault, 2017/02/26
- Re: [Qemu-devel] [PATCH v4 4/5] slirp: VMStatify socket level, Dr. David Alan Gilbert, 2017/02/28
- Re: [Qemu-devel] [PATCH v4 4/5] slirp: VMStatify socket level, Samuel Thibault, 2017/02/28
- Re: [Qemu-devel] [PATCH v4 4/5] slirp: VMStatify socket level, Dr. David Alan Gilbert, 2017/02/28
- Re: [Qemu-devel] [PATCH v4 4/5] slirp: VMStatify socket level, Samuel Thibault, 2017/02/28
- Re: [Qemu-devel] [PATCH v4 4/5] slirp: VMStatify socket level,
Dr. David Alan Gilbert <=
- Re: [Qemu-devel] [PATCH v4 4/5] slirp: VMStatify socket level, Samuel Thibault, 2017/02/28
- Re: [Qemu-devel] [PATCH v4 4/5] slirp: VMStatify socket level, Dr. David Alan Gilbert, 2017/02/28
- Re: [Qemu-devel] [PATCH v4 4/5] slirp: VMStatify socket level, Samuel Thibault, 2017/02/28
[Qemu-devel] [PATCH v4 1/5] slirp: VMState conversion; tcpcb, Dr. David Alan Gilbert (git), 2017/02/20
[Qemu-devel] [PATCH v4 2/5] slirp: VMStatify sbuf, Dr. David Alan Gilbert (git), 2017/02/20
[Qemu-devel] [PATCH v4 5/5] slirp: VMStatify remaining except for loop, Dr. David Alan Gilbert (git), 2017/02/20
Re: [Qemu-devel] [PATCH v4 0/5] SLIRP VMStatification, no-reply, 2017/02/20