Re: [PATCHv2 net-next 2/2] ipv4/fib: send notify when delete source address routes

Ido Schimmel
2023-08-10T15:08:39Z

On Wed, Aug 09, 2023 at 10:02:34PM +0800, Hangbin Liu wrote:
> After deleting an interface address in fib_del_ifaddr(), the function
> scans the fib_info list for stray entries and calls fib_flush() and
> fib_table_flush(). Then the stray entries will be deleted silently and no
> RTM_DELROUTE notification will be sent.
>
> This lack of notification can make routing daemons like NetworkManager,
> miss the routing changes. e.g.

[...]

> To fix this issue, let's add a new bit in "struct fib_info" to track the
> deleted prefer source address routes, and only send notify for them.

In the other thread Thomas mentioned that NM already requests a route
dump following address deletion [1]. If so, can Thomas or you please
explain how this patch is going to help NM? Is the intention to optimize
things and avoid the dump request (which can only work on new kernels)?

[1] https://lore.kernel.org/netdev/07fcfd504148b3c721fda716ad0a549662708407.camel@redhat.com/