Refactor Port number validation

Leverage the recently added _is_int_in_range() function to simpify valid range check

Change-Id: I8b7d81a5dc38598275491291c672d9d885931b10

oslo_utils/netutils.py

@@ -177,19 +177,6 @@ def is_valid_ip(address):
     return is_valid_ipv4(address) or is_valid_ipv6(address)
 
 
-def is_valid_port(port):
-    """Verify that port represents a valid port number.
-
-    .. versionadded:: 1.1.1
-    """
-    try:
-        val = int(port)
-    except (ValueError, TypeError):
-        return False
-
-    return (val > 0 and val <= 65535)
-
-
 def _is_int_in_range(value, start, end):
     """Try to convert value to int and check if it lies within
     range 'start' to 'end'.
@@ -206,6 +193,17 @@ def _is_int_in_range(value, start, end):
     return (start <= val <= end)
 
 
+def is_valid_port(port):
+    """Verify that port represents a valid port number.
+
+    Port can be valid integer having a value of 1 up to and
+    including 65535.
+
+    .. versionadded:: 1.1.1
+    """
+    return _is_int_in_range(port, 1, 65535)
+
+
 def is_valid_icmp_type(type):
     """Verify if ICMP type is valid.