Re: [PATCHv2 net-next] IPv4: add extack info for IPv4 address add/delete

[David Ahern <dsahern@kernel.org>]

On 8/18/23 2:25 AM, Hangbin Liu wrote:
> Add extack info for IPv4 address add/delete, which would be useful for
> users to understand the problem without having to read kernel code.
> 
> No extack message for the ifa_local checking in __inet_insert_ifa() as
> it has been checked in find_matching_ifa().
> 
> Suggested-by: Ido Schimmel <idosch@idosch.org>
> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
> ---
> v2: Lowercase all ipv4 prefix. use one extack msg for ifa_valid checking.
> ---
>  net/ipv4/devinet.c | 23 ++++++++++++++++++++---
>  1 file changed, 20 insertions(+), 3 deletions(-)
> 
> diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
> index 5deac0517ef7..c3658b8755bc 100644
> --- a/net/ipv4/devinet.c
> +++ b/net/ipv4/devinet.c
> @@ -509,6 +509,7 @@ static int __inet_insert_ifa(struct in_ifaddr *ifa, struct nlmsghdr *nlh,
>  				return -EEXIST;
>  			}
>  			if (ifa1->ifa_scope != ifa->ifa_scope) {
> +				NL_SET_ERR_MSG(extack, "ipv4: Invalid scope value");

It's not necessarily an invalid scope, but rather it differs from other
configured addresses on the device. That check goes back to the
beginning of git history, and I do not really get why it matters.

Overall looks ok to me:

Reviewed-by: David Ahern <dsahern@kernel.org>