Re: [PATCH net 3/5] net: netlink: don't set nsid on local notifications

[Nicolas Dichtel <nicolas.dichtel@6wind.com>]

Le 18/05/2026 à 16:06, Ilya Maximets a écrit :
> On 5/18/26 2:56 PM, Nicolas Dichtel wrote:
>> Le 18/05/2026 à 14:46, Ilya Maximets a écrit :
>>
>> [snip]
>>
>>> True and also not really.  The main problem is that ID can be allocated
>>> at any point in time, so the application needs to listen for NEW messages
>>> on the same socket that it is listening for the events that are interesting
>>> to it (to avoid races), if it doesn't want to make a separate GET request
>>> per notification or track all the IDs that were previously checked.  It's a
>>> non-trivial amount of code depending on the application structure.
>> iproute2 handles it ;-)
> 
> I don't think it does.  If I run this in one terminal:
> 
> ip netns add test-ns
> ip netns exec test-ns ip monitor link all-nsid
> 
> And then in the other terminal:
> 
> ip -n test-ns link add dummy1 type dummy
> ip netns exec test-ns ip netns set test-ns 100
> ip -n test-ns link add dummy2 type dummy
> ip netns del test-ns
> 
> I see the following events:
> 
> [nsid current]2: dummy1: <BROADCAST,NOARP> ...
> [nsid 100]3: dummy2: <BROADCAST,NOARP> ...
> 
> Which is confusing to the user (myself) and shows that iproute2 doesn't
> know or doesn't care (which may be fine for this particular command) that
> 100 is the ID of the current namespace.
Right, it doesn't update its cache. I thought I fixed this :D

[snip]

>> I need to make some tests with your series.
> 
> Note: sashiko points out that it may be possible to have stale values reported, so
> re-setting the nsid_is_set flag unconditionally before the check may be required,
> e.g.:
> 
> +  NETLINK_CB(p->skb2).nsid_is_set = false;
>    if (!net_eq(sock_net(sk), p->net)) {
>        NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net);
>        if (NETLINK_CB(p->skb2).nsid != NETNSA_NSID_NOT_ASSIGNED)
>            NETLINK_CB(p->skb2).nsid_is_set = true;
>    }
> 
> I'll include that in v2.
I will wait for the v2 to test the series.

Regards,
Nicolas