ipv4: ICMP packet inspection for multipath
ICMP packets are inspected to let them route together with the flow they
belong to, minimizing the chance that a problematic path will affect flows
on other paths, and so that anycast environments can work with ECMP.
Signed-off-by: Peter Nørlund <pch@ordbogen.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 6b96dee..36e2697 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -440,6 +440,22 @@
icmp_xmit_unlock(sk);
}
+#ifdef CONFIG_IP_ROUTE_MULTIPATH
+
+/* Source and destination is swapped. See ip_multipath_icmp_hash */
+static int icmp_multipath_hash_skb(const struct sk_buff *skb)
+{
+ const struct iphdr *iph = ip_hdr(skb);
+
+ return fib_multipath_hash(iph->daddr, iph->saddr);
+}
+
+#else
+
+#define icmp_multipath_hash_skb(skb) (-1)
+
+#endif
+
static struct rtable *icmp_route_lookup(struct net *net,
struct flowi4 *fl4,
struct sk_buff *skb_in,
@@ -464,7 +480,8 @@
fl4->flowi4_oif = l3mdev_master_ifindex(skb_in->dev);
security_skb_classify_flow(skb_in, flowi4_to_flowi(fl4));
- rt = __ip_route_output_key(net, fl4);
+ rt = __ip_route_output_key_hash(net, fl4,
+ icmp_multipath_hash_skb(skb_in));
if (IS_ERR(rt))
return rt;