Subject: Re: [PATCH iproute2] ip-address: properly display zero IPv4 peer address

From: Stephen Hemminger <[email-masked]>
Date: Mon, 23 Nov 2015 16:04:50 -0800

On Thu, 22 Oct 2015 10:34:28 +0200
Thomas Haller <[email-masked]> wrote:

> Kernel allows for zero IPv4 peer addresses (IFA_ADDRESS):
> 
>    ip address add 192.168.5.1 peer 0.0.0.0/24 dev dummy
> 
> which is distinct from a usual address like:
> 
>    ip address add 192.168.5.1/24 dev dummy
>    ip address add 192.168.5.1 peer 192.168.5.1/24 dev dummy
> 
> For IPv4, a missing IFA_ADDRESS attribute means that the peer
> is 0.0.0.0. See inet_fill_ifaddr(), which does:
> 
>   if ((ifa->ifa_address &&
>        nla_put_in_addr(skb, IFA_ADDRESS, ifa->ifa_address)) ||
> 
> Signed-off-by: Thomas Haller <[email-masked]>

I would prefer that this apply to both IPv4 and IPv6.
If the kernel sends back an address, then display it.