Re: [PATCH nf 2/2] netfilter: use actual socket sk rather than skb sk when routing harder

["Jason A. Donenfeld" <Jason@zx2c4.com>]

As a historical note, this code goes all the way back to Rusty in
2.3.14, where it looked like this:

#ifdef CONFIG_NETFILTER
/* To preserve the cute illusion that a locally-generated packet can
  be mangled before routing, we actually reroute if a hook altered
  the packet. -RR */
static int route_me_harder(struct sk_buff *skb)
{
       struct iphdr *iph = skb->nh.iph;
       struct rtable *rt;

       if (ip_route_output(&rt, iph->daddr, iph->saddr,
                           RT_TOS(iph->tos) | RTO_CONN,
                           skb->sk ? skb->sk->bound_dev_if : 0)) {
               printk("route_me_harder: No more route.\n");
               return -EINVAL;
       }

       /* Drop old route. */
       dst_release(skb->dst);

       skb->dst = &rt->u.dst;
       return 0;
}
#endif

And until now, it was never updated to take the separate sock *sk parameter.