Re: [PATCH v1 net-next 1/5] drop_monitor: import netnamespace framework

On Wed, Jul 12, 2017 at 10:08 AM, 张军伟(基础平台部)
[off-list ref] wrote:

about skb->sk
it is used as supplementary when skb->dev is empty，such as netlink message。

+       if (skb->dev)
+               net = dev_net(skb->dev);
+       else if (skb->sk)
+               net = sock_net(skb->sk);
+       else
+               return;

Check udp_set_dev_scratch().

Again, as Neil mentioned, the idea is arguable, it is actually harder to trace
skb's with your patch when they across netns'es.