Re: [PATCH net-next 0/3] rtnetlink: dump link-layer multicast addresses

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

Le 05/09/2026 à 11:39, Yuyang Huang a écrit :
> "ip maddr show" prints three kinds of entries: link-layer, IPv4 and
> IPv6. The IPv4 and IPv6 ones can be read over netlink today: IPv6 has
> had RTM_GETMULTICAST for a long time and IPv4 got it in eb4e17a1d915
> ("netlink: support dumping IPv4 multicast addresses"), with IFA_MC_USERS
> added later so the user count no longer has to come from procfs.
> > The link-layer list is the missing piece. dev->mc, the addresses
> programmed into the device filter, is only exported via
> /proc/net/dev_mcast, so iproute2 still carries a procfs parser just for
These addresses could be listed with 'bridge fdb' (RTM_GETNEIGH on AF_BRIDGE).
Instead of having a new message to get the missing info (users), maybe it would
be better to update the current API.

> that. This series closes the gap so that "ip maddr show" can be served
> from rtnetlink alone.
> 
> Patch 1 handles RTM_GETMULTICAST dumps with ifa_family set to AF_PACKET
FWIW, AF_PACKET seems strange to me. Isn't AF_UNSPEC (like for interface, cf
rtnl_fill_ifinfo) more appropriate?

Regards,
Nicolas