Re: [PATCH] Socket filter ancilliary data access for skb->dev->type

[Patrick McHardy <kaber@trash.net>]

Paul LeoNerd Evans wrote:
> Add an SKF_AD_HATYPE field to the packet ancilliary data area, giving
> access to skb->dev->type, as reported in the sll_hatype field.
> 
> When capturing packets on a PF_PACKET/SOCK_RAW socket bound to all
> interfaces, there doesn't appear to be a way for the filter program to
> actually find out the underlying hardware type the packet was captured
> on. This patch adds such ability.
> 
> +		case SKF_AD_HATYPE:
> +			A = skb->dev->type;
> +			continue;

I think we should be adding a check whether skb->dev is non-NULL here
since filters can also be attached to netlink sockets. The same applies
to SKF_AD_IFINDEX.