bridge: check vlan id when loading net conf

Signed-off-by: Bruce Ma <brucema19901024@gmail.com>

plugins/main/bridge/bridge.go

@@ -75,6 +75,9 @@ func loadNetConf(bytes []byte) (*NetConf, string, error) {
 	if err := json.Unmarshal(bytes, n); err != nil {
 		return nil, "", fmt.Errorf("failed to load netconf: %v", err)
 	}
+	if n.Vlan < 0 || n.Vlan > 4094 {
+		return nil, "", fmt.Errorf(`invalid VLAN ID %d (must be between 0 and 4094)`, n.Vlan)
+	}
 	return n, n.CNIVersion, nil
 }