+/* Handle redirects */
+struct ip6rd_flowi {
+ struct flowi6 fl6;
+ struct in6_addr gateway;
+};
+
+static struct rt6_info *__ip6_route_redirect(struct net *net,
+ struct fib6_table *table,
+ struct flowi6 *fl6,
+ int flags)
+{
+ struct ip6rd_flowi *rdfl = (struct ip6rd_flowi *)fl6;
+ struct rt6_info *rt;
+ struct fib6_node *fn;
+
+ /* Get the "current" route for this destination and
+ * check if the redirect has come from approriate router.
+ *
+ * RFC 4861 specifies that redirects should only be
+ * accepted if they come from the nexthop to the target.
+ * Due to the way the routes are chosen, this notion
+ * is a bit fuzzy and one might need to check all possible
+ * routes.
+ */
+
+ read_lock_bh(&table->tb6_lock);
+ fn = fib6_lookup(&table->tb6_root, &fl6->daddr, &fl6->saddr);
+restart:
+ for (rt = fn->leaf; rt; rt = rt->dst.rt6_next) {
+ if (rt6_check_expired(rt))
+ continue;
+ if (rt->dst.error)
+ break;
+ if (!(rt->rt6i_flags & RTF_GATEWAY))
+ continue;
+ if (fl6->flowi6_oif != rt->dst.dev->ifindex)
+ continue;
+ if (!ipv6_addr_equal(&rdfl->gateway, &rt->rt6i_gateway))
+ continue;
+ break;
+ }
+
+ if (!rt)
+ rt = net->ipv6.ip6_null_entry;
+ else if (rt->dst.error) {
+ rt = net->ipv6.ip6_null_entry;
+ goto out;
+ }
+ BACKTRACK(net, &fl6->saddr);
+out:
+ dst_hold(&rt->dst);
+
+ read_unlock_bh(&table->tb6_lock);
+
+ return rt;
+};
+
+static struct dst_entry *ip6_route_redirect(struct net *net,
+ const struct flowi6 *fl6,
+ const struct in6_addr *gateway)
+{
+ int flags = RT6_LOOKUP_F_HAS_SADDR;
+ struct ip6rd_flowi rdfl;
+
+ rdfl.fl6 = *fl6;
+ rdfl.gateway = *gateway;
+
+ return fib6_rule_lookup(net, &rdfl.fl6,
+ flags, __ip6_route_redirect);
+}
+