Re: [PATCH 6/6] netns: configurable number of initial network namespaces

[ebiederm@xmission.com (Eric W. Biederman)]

Patrick McHardy <kaber@trash.net> writes:

> Vivien Chappelier wrote:
>>    Yes; the linux-vrf patches had a new netlink message to create/remove the
>> equivalent of a network namespace (ip vrf add 1). I've not ported this feature
>> yet, so this patch is meant to provide another way of setting up networking
>> stacks without the need for a new process for each stack. The ability to
>> dynamically create/remove networking stacks from userspace would definitely be
>> useful.
>
> I see, I didn't realize the process that created a namespace
> needs to be kept running. So yes, creating standalone network
> namespaces seems to make sense

To be clear a reference needs to be kept to the network namespace.
Either by being the network namespace that new sockets are created in
task->nsproxy->netns or the network namespace of an open socket sock_net(sk).

If neither of those two conditions hold the network namespace count drops to
zero and it will be freed.  Probably not ideal if you are just doing routing.

Eric