Added ICMP 'type' and 'code' checking capability to 'netutils' module

ICMP has 'type' and 'code' fields which are used while adding a security
group rule using Horizon. I have written functions in 'netutils' module
which validate ICMP 'type' and 'code' fields.

Change-Id: Ie1a67ea1afd69d5de4326f9e9a7243362b912582
Closes-Bug: #1511940

oslo_utils/netutils.py

@@ -178,6 +178,48 @@ def is_valid_port(port):
     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'.
+
+    :param value: value to verify
+    :param start: start number of range
+    :param end: end number of range
+    :returns: bool
+    """
+    try:
+        val = int(value)
+    except (ValueError, TypeError):
+        return False
+    return (start <= val <= end)
+
+
+def is_valid_icmp_type(type):
+    """Verify if ICMP type is valid.
+
+    :param type: ICMP *type* field can only be a valid integer
+    :returns: bool
+
+    ICMP *type* field can be valid integer having a value of 0
+    up to and including 255.
+    """
+    return _is_int_in_range(type, 0, 255)
+
+
+def is_valid_icmp_code(code):
+    """Verify if ICMP code is valid.
+
+    :param code: ICMP *code* field can be valid integer or None
+    :returns: bool
+
+    ICMP *code* field can be either None or valid integer having
+    a value of 0 up to and including 255.
+    """
+    if code is None:
+        return True
+    return _is_int_in_range(code, 0, 255)
+
+
 def get_my_ipv4():
     """Returns the actual ipv4 of the local machine.
 

oslo_utils/tests/test_netutils.py

@@ -199,6 +199,44 @@ class NetworkUtilsTest(test_base.BaseTestCase):
             addr = netutils.get_my_ipv4()
         self.assertEqual(addr, '1.2.3.4')
 
+    def test_is_int_in_range(self):
+        valid_inputs = [(1, -100, 100),
+                        ('1', -100, 100),
+                        (100, -100, 100),
+                        ('100', -100, 100),
+                        (-100, -100, 100),
+                        ('-100', -100, 100)]
+        for input_value in valid_inputs:
+            self.assertTrue(netutils._is_int_in_range(*input_value))
+
+    def test_is_int_not_in_range(self):
+        invalid_inputs = [(None, 1, 100),
+                          ('ten', 1, 100),
+                          (-1, 0, 255),
+                          ('None', 1, 100)]
+        for input_value in invalid_inputs:
+            self.assertFalse(netutils._is_int_in_range(*input_value))
+
+    def test_valid_icmp_type(self):
+        valid_inputs = [1, '1', 0, '0', 255, '255']
+        for input_value in valid_inputs:
+            self.assertTrue(netutils.is_valid_icmp_type(input_value))
+
+    def test_invalid_icmp_type(self):
+        invalid_inputs = [-1, '-1', 256, '256', None, 'None', 'five']
+        for input_value in invalid_inputs:
+            self.assertFalse(netutils.is_valid_icmp_type(input_value))
+
+    def test_valid_icmp_code(self):
+        valid_inputs = [1, '1', 0, '0', 255, '255', None]
+        for input_value in valid_inputs:
+            self.assertTrue(netutils.is_valid_icmp_code(input_value))
+
+    def test_invalid_icmp_code(self):
+        invalid_inputs = [-1, '-1', 256, '256', 'None', 'zero']
+        for input_value in invalid_inputs:
+            self.assertFalse(netutils.is_valid_icmp_code(input_value))
+
     @mock.patch('socket.socket')
     @mock.patch('oslo_utils.netutils._get_my_ipv4_address')
     def test_get_my_ip_socket_error(self, ip, mock_socket):