Merge "Do not initialize the iptables nat table in the dhcp-agent"

neutron/agent/linux/dhcp.py

@@ -1589,6 +1589,7 @@ class DeviceManager(object):
     def fill_dhcp_udp_checksums(self, namespace):
         """Ensure DHCP reply packets always have correct UDP checksums."""
         iptables_mgr = iptables_manager.IptablesManager(use_ipv6=True,
+                                                        nat=False,
                                                         namespace=namespace)
         ipv4_rule = ('-p udp -m udp --dport %d -j CHECKSUM --checksum-fill'
                      % constants.DHCP_RESPONSE_PORT)

neutron/agent/linux/iptables_manager.py

@@ -308,7 +308,7 @@ class IptablesManager(object):
     _random_fully = None
 
     def __init__(self, _execute=None, state_less=False, use_ipv6=False,
-                 namespace=None, binary_name=binary_name):
+                 nat=True, namespace=None, binary_name=binary_name):
         if _execute:
             self.execute = _execute
         else:
@@ -348,7 +348,8 @@ class IptablesManager(object):
 
         if not state_less:
             self.initialize_mangle_table()
-            self.initialize_nat_table()
+            if nat:
+                self.initialize_nat_table()
 
     def initialize_mangle_table(self):
         self.ipv4.update(

neutron/tests/unit/agent/linux/test_iptables_manager.py

@@ -1340,3 +1340,23 @@ class IptablesManagerStateLessTestCase(base.BaseTestCase):
         iptables.initialize_nat_table()
         self.assertIn('nat', iptables.ipv4)
         self.assertNotIn('mangle', iptables.ipv4)
+
+
+class IptablesManagerNoNatTestCase(base.BaseTestCase):
+
+    def setUp(self):
+        super(IptablesManagerNoNatTestCase, self).setUp()
+        cfg.CONF.set_override('comment_iptables_rules', False, 'AGENT')
+        self.iptables = (iptables_manager.IptablesManager(nat=False))
+
+    def test_nat_not_found(self):
+        self.assertNotIn('nat', self.iptables.ipv4)
+
+    def test_mangle_found(self):
+        self.assertIn('mangle', self.iptables.ipv4)
+
+    def test_initialize_nat_table(self):
+        iptables = iptables_manager.IptablesManager(nat=False)
+        iptables.initialize_nat_table()
+        self.assertIn('nat', iptables.ipv4)
+        self.assertIn('mangle', iptables.ipv4)