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From: David Lamparter <equinox@diac24.net>
To: jamal <hadi@cyberus.ca>
Cc: David Lamparter <equinox@diac24.net>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	linux-kernel@vger.kernel.org,
	Linux Containers <containers@lists.osdl.org>,
	netdev@vger.kernel.org, netfilter-devel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 7/8] net: Allow setting the network namespace by fd
Date: Fri, 24 Sep 2010 14:57:04 +0200	[thread overview]
Message-ID: <20100924125704.GA1551619@jupiter.n2.diac24.net> (raw)
In-Reply-To: <1285329084.13976.661.camel@bigi>

On Fri, Sep 24, 2010 at 07:51:24AM -0400, jamal wrote:
> > migrating route table entries makes no sense because
> > a) they refer to devices and configuration that does not exist in the
> >    target namespace; they only make sense within their netns context
> > b) they are purely virtual and you get the same result from deleting and
> >    recreating them.
> > 
> > Network devices are special because they may have something attached to
> > them, be it hardware or some daemon.
> 
> Routes functionally reside on top of netdevices, point to nexthop
> neighbors across these netdevices etc. Underlying assumption is you take
> care of that dependency when migrating.
> We are talking about FIB entries here not the route cache; moving a few
> pointers within the kernel is a hell lot faster than recreating a subset
> of BGP entries from user space. 

No. While you sure could associate routes with devices, they don't
*functionally* reside on top of network devices. They reside on top of
the entire IP configuration, and in case of BGP they even reside on top
of your set of peerings and their data.

Even if you could "move" routes together with a network device, the
result would be utter nonsense. The routes depend on your BGP view, and
if your set of interfaces (and peers) changes, your routes will change.
Your bgpd will, either way, need to set up new peerings and redo best
path evaluations.

(On an unrelated note, how often are you planning to move stuff between
namespaces? I don't expect to be moving stuff except on configuration
events...)


-David


  reply	other threads:[~2010-09-24 12:57 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-23  8:45 [ABI REVIEW][PATCH 0/8] Namespace file descriptors Eric W. Biederman
2010-09-23  8:46 ` [PATCH 1/8] ns: proc files for namespace naming policy Eric W. Biederman
2010-09-23  8:46 ` [PATCH 2/8] ns: Introduce the setns syscall Eric W. Biederman
2010-09-23  8:47 ` [PATCH 3/8] ns proc: Add support for the network namespace Eric W. Biederman
2010-09-23 11:27   ` Louis Rilling
2010-09-23 16:00     ` Eric W. Biederman
2010-09-23  8:48 ` [PATCH 4/8] ns proc: Add support for the uts namespace Eric W. Biederman
2010-09-23  8:49 ` [PATCH 5/8] ns proc: Add support for the ipc namespace Eric W. Biederman
2010-09-23  8:50 ` [PATCH 6/8] ns proc: Add support for the mount namespace Eric W. Biederman
2010-09-23  8:51 ` [PATCH 7/8] net: Allow setting the network namespace by fd Eric W. Biederman
2010-09-23  9:41   ` Eric Dumazet
2010-09-23 16:03     ` Eric W. Biederman
2010-09-23 11:22   ` jamal
2010-09-23 14:58     ` David Lamparter
2010-09-24 11:51       ` jamal
2010-09-24 12:57         ` David Lamparter [this message]
2010-09-24 13:32           ` jamal
2010-09-24 14:09             ` David Lamparter
2010-09-24 14:16               ` jamal
2010-09-23 15:14     ` Eric W. Biederman
2010-09-23 14:22   ` Brian Haley
2010-09-23 16:16     ` Eric W. Biederman
2010-09-24 13:46   ` Daniel Lezcano
2010-09-23  8:51 ` [PATCH 8/8] net: Implement socketat Eric W. Biederman
2010-09-23  8:56   ` Pavel Emelyanov
2010-09-23 11:19     ` jamal
2010-09-23 11:33       ` Pavel Emelyanov
2010-09-23 11:40         ` jamal
2010-09-23 11:53           ` Pavel Emelyanov
2010-09-23 12:11             ` jamal
2010-09-23 12:34               ` Pavel Emelyanov
2010-09-23 14:54                 ` David Lamparter
2010-09-23 15:00                 ` Eric W. Biederman
2010-10-02 21:13             ` Daniel Lezcano
2010-10-03 13:44               ` jamal
2010-10-04 10:13                 ` Daniel Lezcano
2010-10-04 19:07                 ` Eric W. Biederman
2010-10-15 12:30                 ` netns patches WAS( " jamal
2010-10-26 20:52                   ` jamal
2010-10-27  0:27                     ` Eric W. Biederman
2010-09-23 15:18 ` [ABI REVIEW][PATCH 0/8] Namespace file descriptors David Lamparter
2010-09-23 16:32   ` Eric W. Biederman
2010-09-23 16:49     ` David Lamparter
2010-09-24 13:02 ` Andrew Lutomirski
2010-09-24 13:49   ` Daniel Lezcano
2010-09-24 17:06     ` Eric W. Biederman

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