-static inline struct rtable *route_reverse(struct sk_buff *skb,
- struct tcphdr *tcph, int hook)
-{
- struct iphdr *iph = skb->nh.iph;
- struct dst_entry *odst;
- struct flowi fl = {};
- struct rtable *rt;
-
- /* We don't require ip forwarding to be enabled to be able to
- * send a RST reply for bridged traffic. */
- if (hook != NF_IP_FORWARD
-#ifdef CONFIG_BRIDGE_NETFILTER
- || (skb->nf_bridge && skb->nf_bridge->mask & BRNF_BRIDGED)
-#endif
- ) {
- fl.nl_u.ip4_u.daddr = iph->saddr;
- if (hook == NF_IP_LOCAL_IN)
- fl.nl_u.ip4_u.saddr = iph->daddr;
- fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
-
- if (ip_route_output_key(&rt, &fl) != 0)
- return NULL;
- } else {
- /* non-local src, find valid iif to satisfy
- * rp-filter when calling ip_route_input. */
- fl.nl_u.ip4_u.daddr = iph->daddr;
- if (ip_route_output_key(&rt, &fl) != 0)
- return NULL;
-
- odst = skb->dst;
- if (ip_route_input(skb, iph->saddr, iph->daddr,
- RT_TOS(iph->tos), rt->u.dst.dev) != 0) {
- dst_release(&rt->u.dst);
- return NULL;
- }
- dst_release(&rt->u.dst);
- rt = (struct rtable *)skb->dst;
- skb->dst = odst;
-
- fl.nl_u.ip4_u.daddr = iph->saddr;
- fl.nl_u.ip4_u.saddr = iph->daddr;
- fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
- }
-
- if (rt->u.dst.error) {
- dst_release(&rt->u.dst);
- return NULL;
- }
-
- fl.proto = IPPROTO_TCP;
- fl.fl_ip_sport = tcph->dest;
- fl.fl_ip_dport = tcph->source;
-
- xfrm_lookup((struct dst_entry **)&rt, &fl, NULL, 0);
-
- return rt;
-}
-