Subject: Re: [PATCH net-next v4 1/4] netns: add genl cmd to add and get peer netns ids

From: Nicolas Dichtel <[email-masked]>
Date: Fri, 31 Oct 2014 10:41:24 +0100

Le 30/10/2014 19:35, Eric W. Biederman a écrit :
> Nicolas Dichtel <[email-masked]> writes:
>
>> With this patch, a user can define an id for a peer netns by providing a FD or a
>> PID. These ids are local to netns (ie valid only into one netns).
>
> Scratches head.  Do you actually find value in using the pid instead of
> a file descriptor?
I copied the mechanism from rtnl_link_get_net():
First check if the user provides a PID, if not, check for a FD.

>
> Doing things by pid was an early attempt to make things work, and has
> been a bit clutsy.  If you don't find value in it I would recommend just
> supporting getting/setting the network namespace by file descriptor.
Hmm, if I understand well, it's what is done in the patch:

[snip]
>> +static int netns_nl_cmd_newid(struct sk_buff *skb, struct genl_info *info)
>> +{
[snip]
>> +	if (info->attrs[NETNSA_PID])
>> +		peer = get_net_ns_by_pid(nla_get_u32(info->attrs[NETNSA_PID]));
>> +	else if (info->attrs[NETNSA_FD])
>> +		peer = get_net_ns_by_fd(nla_get_u32(info->attrs[NETNSA_FD]));
>> +	else
>> +		return -EINVAL;
>> +	if (IS_ERR(peer))
>> +		return PTR_ERR(peer);

Am I right?

Regards,
Nicolas