Only handle valid CNI_ARGS

If arguments fail to parse, continue without additional endpoint
configuration.

common/core/network.go

@@ -105,12 +105,6 @@ func (plugin *netPlugin) Add(args *cniSkel.CmdArgs) (resultError error) {
 		k8sNamespace = string(podConfig.K8S_POD_NAMESPACE)
 	}
 
-	epConfig, err := cni.ParseCniEndpointArgs(args.Args)
-	if err != nil {
-		logrus.Errorf("[cni-net] Failed to parse endpoint args, err:%v", err)
-		return err
-	}
-
 	// Parse network configuration from stdin.
 	cniConfig, err := cni.ParseNetworkConfig(args.StdinData)
 	if err != nil {
@@ -139,14 +133,17 @@ func (plugin *netPlugin) Add(args *cniSkel.CmdArgs) (resultError error) {
 		return err
 	}
 
-	if epConfig.MAC != "" {
-		hwAddr, err := net.ParseMAC(string(epConfig.MAC))
-		if err != nil {
-			logrus.Errorf("[cni-net] Failed to parse MAC addres '%s', err:%v", epConfig.MAC, err)
-			return err
-		}
+	epConfig, err := cni.ParseCniEndpointArgs(args.Args)
+	if err == nil {
+		if epConfig.MAC != "" {
+			hwAddr, err := net.ParseMAC(string(epConfig.MAC))
+			if err != nil {
+				logrus.Errorf("[cni-net] Failed to parse MAC addres '%s', err:%v", epConfig.MAC, err)
+				return err
+			}
 
-		epInfo.MacAddress = hwAddr
+			epInfo.MacAddress = hwAddr
+		}
 	}
 	epInfo.DualStack = cniConfig.OptionalFlags.EnableDualStack