summary refs log tree commit diff
path: root/net/ipv6/icmp.c
diff options
context:
space:
mode:
authorJakub Sitnicki <jkbs@redhat.com>2017-08-23 09:58:29 +0200
committerDavid S. Miller <davem@davemloft.net>2017-08-24 18:21:17 -0700
commit23aebdacb05dab9efdf22b9e0413491cbd5f128f (patch)
treec686bd03925a2d68a4438b5ec39c92b027f4e76d /net/ipv6/icmp.c
parent29825717123fb9cfb9e709327d565c2f2fa89903 (diff)
downloadlinux-23aebdacb05dab9efdf22b9e0413491cbd5f128f.tar.gz
ipv6: Compute multipath hash for ICMP errors from offending packet
When forwarding or sending out an ICMPv6 error, look at the embedded
packet that triggered the error and compute a flow hash over its
headers.

This let's us route the ICMP error together with the flow it belongs to
when multipath (ECMP) routing is in use, which in turn makes Path MTU
Discovery work in ECMP load-balanced or anycast setups (RFC 7690).

Granted, end-hosts behind the ECMP router (aka servers) need to reflect
the IPv6 Flow Label for PMTUD to work.

The code is organized to be in parallel with ipv4 stack:

  ip_multipath_l3_keys -> ip6_multipath_l3_keys
  fib_multipath_hash   -> rt6_multipath_hash

Signed-off-by: Jakub Sitnicki <jkbs@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/icmp.c')
-rw-r--r--net/ipv6/icmp.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 4f82830fc068..dd7608cf1d72 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -519,6 +519,7 @@ static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
 	fl6.fl6_icmp_type = type;
 	fl6.fl6_icmp_code = code;
 	fl6.flowi6_uid = sock_net_uid(net, NULL);
+	fl6.mp_hash = rt6_multipath_hash(&fl6, skb);
 	security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 
 	sk = icmpv6_xmit_lock(net);