ofp-actions: Correct pop MPLS ethtype as consistency test

Correct pop MPLS ethtype consistency check to verify that
the packet has an MPLS ethtype before the pop action rather than after:
an MPLS ethtype is a pre-condition but not a post-condition of pop MPLS.

With this change the consistency check in ofpact_check__()
becomes consistent with that in ofpact_from_nxast().

This was found using Ryu tests via the new make check-ryu target.
It allows all of the "POP_MPLS"[1] tests to pass where they previously
failed.

[1] http://osrg.github.io/ryu-certification/switch/ovs

Cc: Jarno Rajahalme <jrajahalme@nicira.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Ben Pfaff <blp@nicira.com>

diff --git a/lib/ofp-actions.c b/lib/ofp-actions.c
index 781c3a1..3cd1e8b 100644 (file)
--- a/lib/ofp-actions.c
+++ b/lib/ofp-actions.c
@@ -2067,10 +2067,10 @@ ofpact_check__(enum ofputil_protocol *usable_protocols, struct ofpact *a,
         return 0;
 
     case OFPACT_POP_MPLS:
-        flow->dl_type = ofpact_get_POP_MPLS(a)->ethertype;
         if (!eth_type_mpls(flow->dl_type)) {
             inconsistent_match(usable_protocols);
         }
+        flow->dl_type = ofpact_get_POP_MPLS(a)->ethertype;
         return 0;
 
     case OFPACT_SAMPLE: