Re: [PATCH] net: add net namespace inode for all net_dev events

On Tue, 9 Mar 2021 at 20:12, Eric Dumazet [off-list ref] wrote:

On 3/9/21 5:43 AM, Tony Lu wrote:

quoted

There are lots of net namespaces on the host runs containers like k8s.
It is very common to see the same interface names among different net
namespaces, such as eth0. It is not possible to distinguish them without
net namespace inode.

This adds net namespace inode for all net_dev events, help us
distinguish between different net devices.

Output:
  <idle>-0       [006] ..s.   133.306989: net_dev_xmit: net_inum=4026531992 dev=eth0 skbaddr=0000000011a87c68 len=54 rc=0

Signed-off-by: Tony Lu <tonylu@linux.alibaba.com>
---

There was a proposal from Lorenz to use netns cookies (SO_NETNS_COOKIE) instead.

They have a guarantee of being not reused.

After 3d368ab87cf6681f9 ("net: initialize net->net_cookie at netns setup")
net->net_cookie is directly available.

The patch set is at
https://lore.kernel.org/bpf/20210219154330.93615-1-lmb@cloudflare.com/ (local)
but I decided to abandon it. I can work around my issue by comparing
the netns inode of two processes, which is "good enough" for now.

-- 
Lorenz Bauer  |  Systems Engineer
6th Floor, County Hall/The Riverside Building, SE1 7PB, UK

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