Messages in this thread | | | Subject | Re: [PATCH net-next v1 3/5] ipv4: enable IFA_IF_NETNSID for RTM_GETADDR | From | David Ahern <> | Date | Tue, 4 Sep 2018 10:27:51 -0600 |
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On 9/4/18 12:50 AM, Jiri Benc wrote: > > This is a general problem with netlink: unknown attributes are ignored. > We need a way to detect that certain attribute was understood by the > kernel or was not. And it needs to work retroactively, i.e. the > application has to be able to determine the currently running kernel > does not support the feature (because it's too old).
sure, and that has been discussed before.
> > That's why we return back the attribute in responses to a request with > IFLA_IF_NETNSID present and why we should do the same for > IFA_IF_NETNSID. > >> See 21fdd092acc7e. I would like to see other filters added for addresses >> in the same release this gets used. The only one that comes to mind for >> addresses is to only return addresses for devices with master device >> index N (same intent as 21fdd092acc7e for neighbors). > > I also question the statement that IFA_F_NETNSID is a filter: my > understanding of "filter" is something that limits the output to a > certain subset. I.e., unfiltered results always contain everything that > is in a filtered result. While with IFA_F_NETNSID, we get a completely > different set of data. Does that really constitute a filter? Note that > we can still filter in the target netns. >
I'll buy that argument over the 'too coarse' one. Looking at the link version of this flag, the NLM_F_DUMP_FILTERED flag is not used there so for consistency the address one should follow suit.
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