Re: [PATCH net-next v5 0/4] netns: allow to identify peer netns

[David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>]

From: Nicolas Dichtel <nicolas.dichtel-pdR9zngts4EAvxtiuMwx3w@public.gmane.org>
Date: Thu, 15 Jan 2015 15:11:14 +0100

> The goal of this serie is to be able to multicast netlink messages with an
> attribute that identify a peer netns.
> This is needed by the userland to interpret some information contained in
> netlink messages (like IFLA_LINK value, but also some other attributes in case
> of x-netns netdevice (see also
> http://thread.gmane.org/gmane.linux.network/315933/focus=316064 and
> http://thread.gmane.org/gmane.linux.kernel.containers/28301/focus=4239)).
> 
> Ids of peer netns can be set by userland via a new rtnl cmd RTM_NEWNSID. When
> the kernel needs an id for a peer (for example when advertising a new x-netns
> interface via netlink), if the user didn't allocate an id, one will be
> automatically allocated.
> These ids are stored per netns and are local (ie only valid in the netns where
> they are set). To avoid allocating an int for each peer netns, I use
> idr_for_each() to retrieve the id of a peer netns. Note that it will be possible
> to add a table (struct net -> id) later to optimize this lookup if needed.
> 
> Patch 1/4 introduces the rtnetlink API mechanism to set and get these ids.
> Patch 2/4 and 3/4 implements an example of how to use these ids when advertising
> information about a x-netns interface.
> And patch 4/4 shows that the netlink messages can be symetric between a GET and
> a SET.
 ...

Seires applied, thanks.