Delete fastdp bridge MACs when invalidating routes

The absence of the deletion might lead to installation of invalid
flows, because the fastdp bridge MAC cache can have stale entries
which are used when deciding when/what flows to create.

Author: brb

router/fastdp.go

@@ -302,13 +302,20 @@ func (fastdp fastDatapathOverlay) InvalidateRoutes() {
 	log.Debug("InvalidateRoutes")
 	fastdp.lock.Lock()
 	defer fastdp.lock.Unlock()
-	checkWarn(fastdp.deleteFlows())
+	fastdp.deleteFlowsAndMACs()
 }
 
 func (fastdp fastDatapathOverlay) InvalidateShortIDs() {
 	log.Debug("InvalidateShortIDs")
 	fastdp.lock.Lock()
 	defer fastdp.lock.Unlock()
+	fastdp.deleteFlowsAndMACs()
+}
+
+// NB: The fastdp lock has to be taken before calling.
+func (fastdp *FastDatapath) deleteFlowsAndMACs() {
+	fastdp.sendToMAC = make(map[MAC]bridgeSender)
+	fastdp.seenMACs = make(map[MAC]struct{})
 	checkWarn(fastdp.deleteFlows())
 }
 
@@ -1023,7 +1030,7 @@ func (fastdp *FastDatapath) makeBridgeVport(vport odp.Vport) {
 
 	// Delete flows, in order to recalculate flows for broadcasts
 	// on the bridge.
-	checkWarn(fastdp.deleteFlows())
+	fastdp.deleteFlowsAndMACs()
 
 	// Packets coming from the netdev are processed by the bridge
 	fastdp.missHandlers[vportID] = func(flowKeys odp.FlowKeys, lock *fastDatapathLock) FlowOp {