ofproto: Ignore generation ID for role change to "equal".

The OpenFlow specification says that only role changes to slave or master
check the generation ID, so this is a bug fix.

OpenFlow 1.2 section A.3.9 phrases the requirement this way:

    Additionally, if the role value in the message is OFPCR_ROLE_MASTER
    or OFPCR_ROLE_SLAVE, the switch must validate generation_id to check
    for stale messages.

Found by OFTest.

Signed-off-by: Ben Pfaff <blp@nicira.com>

diff --git a/ofproto/ofproto.c b/ofproto/ofproto.c
index 6dda3cd..a255203 100644 (file)
--- a/ofproto/ofproto.c
+++ b/ofproto/ofproto.c
@@ -5255,7 +5255,8 @@ handle_role_request(struct ofconn *ofconn, const struct ofp_header *oh)
     }
 
     if (request.role != OFPCR12_ROLE_NOCHANGE) {
-        if (request.have_generation_id
+        if (request.role != OFPCR12_ROLE_EQUAL
+            && request.have_generation_id
             && !ofconn_set_master_election_id(ofconn, request.generation_id)) {
                 return OFPERR_OFPRRFC_STALE;
         }