Subject: Re: [PATCH net-next 2/2] net: original ingress device index in PKTINFO

From: Shmulik Ladkani <[email-masked]>
Date: Sat, 7 May 2016 11:41:48 +0300

Hi David,

On Fri,  6 May 2016 18:49:41 -0700 David Ahern <[email-masked]> wrote:
> Applications such as OSPF and BFD need the original ingress device not
> the VRF device;

Would you consider this true for any IP_PKTINFO users in VRF setups?

> @@ -1193,7 +1193,12 @@ void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb)
>  		       ipv6_sk_rxinfo(sk);
>  
>  	if (prepare && skb_rtable(skb)) {
> -		pktinfo->ipi_ifindex = inet_iif(skb);
> +		/* skb->cb is overloaded: prior to this point it is IP{6}CB
> +		 * which has interface index (iif) as the first member of the
> +		 * underlying inet{6}_skb_parm struct. This code then overlays
> +		 * PKTINFO_SKB_CB and in_pktinfo also has iif as the first
> +		 * element so the iif is picked up from the prior IPCB
> +		 */

Better if there was a guarantee in the code that inet_skb_parm layout stays
that way. Or instead just explicitly assign the iif.

Regards,
Shmulik