Re: [PATCH net-next v1 3/5] ipv4: enable IFA_IF_NETNSID for RTM_GETADDR

[David Ahern]

On 9/2/18 10:37 PM, Christian Brauner wrote:
> - Backwards Compatibility:
>   If userspace wants to determine whether ipv4 RTM_GETADDR requests support
>   the new IFA_IF_NETNSID property they should verify that the reply after
>   sending a request includes the IFA_IF_NETNSID property. If it does not
>   userspace should assume that IFA_IF_NETNSID is not supported for ipv4
>   RTM_GETADDR requests on this kernel.

Can only use it once per message type, but NLM_F_DUMP_FILTERED is a flag
that can be set to explicitly say the request is filtered as requested.
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).