datapath: Fix parsing invalid LLC/SNAP ethertypes

Before this patch, if an LLC/SNAP packet with OUI 00:00:00 had an ethertype
less than 1536 the flow key given to userspace in the upcall would contain the
invalid ethertype (for example, 3). If userspace attempted to insert a kernel
flow for this key it would be rejected by ovs_flow_from_nlattrs.

This patch allows OVS to pass the OFTest pktact.DirectBadLlcPackets.

Signed-off-by: Rich Lane <rlane@bigswitch.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/lib/flow.c b/lib/flow.c
index 2a3dd3d9..4e87ef2e 100644
--- a/lib/flow.c
+++ b/lib/flow.c
@@ -132,7 +132,12 @@ parse_ethertype(struct ofpbuf *b)
     }
 
     ofpbuf_pull(b, sizeof *llc);
-    return llc->snap.snap_type;
+
+    if (ntohs(llc->snap.snap_type) >= ETH_TYPE_MIN) {
+        return llc->snap.snap_type;
+    }
+
+    return htons(FLOW_DL_TYPE_NONE);
 }
 
 static int