ecnconfig check against invalid argument value (sonic-net#343)

Signed-off-by: Wenda <[email protected]>

Author: wendani

scripts/ecnconfig

@@ -106,6 +106,11 @@ class EcnConfig(object):
     def set_wred_threshold(self, profile, threshold, value):
         if os.geteuid() != 0:
             sys.exit("Root privileges required for this operation")
+
+        v = int(value)
+        if v < 0 :
+            raise Exception("Invalid %s" % (threshold))
+
         field = WRED_CONFIG_FIELDS[threshold]
         if self.verbose:
             print("Setting %s value to %s" % (field, value))
@@ -114,6 +119,11 @@ class EcnConfig(object):
     def set_wred_prob(self, profile, drop_color, value):
         if os.geteuid() != 0:
             sys.exit("Root privileges required for this operation")
+
+        v = int(value)
+        if v < 0 or v > 100:
+            raise Exception("Invalid %s" % (drop_color))
+
         field = WRED_CONFIG_FIELDS[drop_color]
         if self.verbose:
             print("Setting %s value to %s%%" % (field, value))