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

From: Nicolas Dichtel
Date: Fri Oct 31 2014 - 05:41:38 EST


Le 30/10/2014 19:35, Eric W. Biederman a Ãcrit :
Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx> 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
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