Re: [PATCH net-next, v5] netlink: add IGMP/MLD join/leave notifications

[Hangbin Liu <liuhangbin@gmail.com>]

On Fri, Dec 06, 2024 at 01:10:25PM +0900, Yuyang Huang wrote:
> This change introduces netlink notifications for multicast address
> changes. The following features are included:
> * Addition and deletion of multicast addresses are reported using
>   RTM_NEWMULTICAST and RTM_DELMULTICAST messages with AF_INET and
>   AF_INET6.
> * Two new notification groups: RTNLGRP_IPV4_MCADDR and
>   RTNLGRP_IPV6_MCADDR are introduced for receiving these events.
> 
> This change allows user space applications (e.g., ip monitor) to
> efficiently track multicast group memberships by listening for netlink
> events. Previously, applications relied on inefficient polling of
> procfs, introducing delays. With netlink notifications, applications
> receive realtime updates on multicast group membership changes,
> enabling more precise metrics collection and system monitoring. 
> 
> This change also unlocks the potential for implementing a wide range
> of sophisticated multicast related features in user space by allowing
> applications to combine kernel provided multicast address information
> with user space data and communicate decisions back to the kernel for
> more fine grained control. This mechanism can be used for various
> purposes, including multicast filtering, IGMP/MLD offload, and
> IGMP/MLD snooping.
> 
> Cc: Maciej Żenczykowski <maze@google.com>
> Cc: Lorenzo Colitti <lorenzo@google.com>
> Co-developed-by: Patrick Ruddy <pruddy@vyatta.att-mail.com>
> Signed-off-by: Patrick Ruddy <pruddy@vyatta.att-mail.com>
> Link: https://lore.kernel.org/r/20180906091056.21109-1-pruddy@vyatta.att-mail.com
> Signed-off-by: Yuyang Huang <yuyanghuang@google.com>
> ---

Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>