DHCP agent should check interface is UP before adding route

The DHCP agent should check not only that an interface for
network's DHCP exists but also make sure that is UP before
adding a default route.
For this purpose a method "ensure_device_is_ready" was
added to ip_lib.

Change-Id: I9af06aa0f39634fe7b63c064337cd4191db5c026
Closes-bug: #1302312

diff --git a/neutron/agent/linux/dhcp.py b/neutron/agent/linux/dhcp.py
index 81a9b17dab914b9f30d459e313fe9042f139b8da..3a26dc263b98f1c0fd3d8774150db6e3975445ee 100644 (file)
--- a/neutron/agent/linux/dhcp.py
+++ b/neutron/agent/linux/dhcp.py
@@ -815,9 +815,9 @@ class DeviceManager(object):
         port = self.setup_dhcp_port(network)
         interface_name = self.get_interface_name(network, port)
 
-        if ip_lib.device_exists(interface_name,
-                                self.root_helper,
-                                network.namespace):
+        if ip_lib.ensure_device_is_ready(interface_name,
+                                         self.root_helper,
+                                         network.namespace):
             LOG.debug(_('Reusing existing device: %s.'), interface_name)
         else:
             self.driver.plug(network.id,

diff --git a/neutron/agent/linux/ip_lib.py b/neutron/agent/linux/ip_lib.py
index 9b7f2c8615e569c2d554ed4078ab42f0931f09d3..9b259a163c8e121f1fbc118422b9869fb95a4c37 100644 (file)
--- a/neutron/agent/linux/ip_lib.py
+++ b/neutron/agent/linux/ip_lib.py
@@ -482,6 +482,17 @@ def device_exists(device_name, root_helper=None, namespace=None):
     return bool(address)
 
 
+def ensure_device_is_ready(device_name, root_helper=None, namespace=None):
+    dev = IPDevice(device_name, root_helper, namespace)
+    try:
+        # Ensure the device is up, even if it is already up. If the device
+        # doesn't exist, a RuntimeError will be raised.
+        dev.link.set_up()
+    except RuntimeError:
+        return False
+    return True
+
+
 def iproute_arg_supported(command, arg, root_helper=None):
     command += ['help']
     stdout, stderr = utils.execute(command, root_helper=root_helper,

diff --git a/neutron/tests/unit/test_dhcp_agent.py b/neutron/tests/unit/test_dhcp_agent.py
index 61b63d4b256d5090981c54c668427c705e740efe..f34a1650485cccfa86f44d4e8837bfb156d5e4e5 100644 (file)
--- a/neutron/tests/unit/test_dhcp_agent.py
+++ b/neutron/tests/unit/test_dhcp_agent.py
@@ -1088,9 +1088,9 @@ class TestDeviceManager(base.BaseTestCase):
         cfg.CONF.set_override('use_namespaces', True)
         cfg.CONF.set_override('enable_isolated_metadata', True)
 
-        self.device_exists_p = mock.patch(
-            'neutron.agent.linux.ip_lib.device_exists')
-        self.device_exists = self.device_exists_p.start()
+        self.ensure_device_is_ready_p = mock.patch(
+            'neutron.agent.linux.ip_lib.ensure_device_is_ready')
+        self.ensure_device_is_ready = (self.ensure_device_is_ready_p.start())
 
         self.dvr_cls_p = mock.patch('neutron.agent.linux.interface.NullDriver')
         self.iproute_cls_p = mock.patch('neutron.agent.linux.'
@@ -1104,13 +1104,13 @@ class TestDeviceManager(base.BaseTestCase):
         driver_cls.return_value = self.mock_driver
         iproute_cls.return_value = self.mock_iproute
 
-    def _test_setup_helper(self, device_exists, net=None, port=None):
+    def _test_setup_helper(self, device_is_ready, net=None, port=None):
         net = net or fake_network
         port = port or fake_port1
         plugin = mock.Mock()
         plugin.create_dhcp_port.return_value = port or fake_port1
         plugin.get_dhcp_port.return_value = port or fake_port1
-        self.device_exists.return_value = device_exists
+        self.ensure_device_is_ready.return_value = device_is_ready
         self.mock_driver.get_device_name.return_value = 'tap12345678-12'
 
         dh = dhcp.DeviceManager(cfg.CONF, cfg.CONF.root_helper, plugin)
@@ -1135,7 +1135,7 @@ class TestDeviceManager(base.BaseTestCase):
                 expected_ips,
                 namespace=net.namespace)]
 
-        if not device_exists:
+        if not device_is_ready:
             expected.insert(1,
                             mock.call.plug(net.id,
                                            port.id,
@@ -1152,7 +1152,7 @@ class TestDeviceManager(base.BaseTestCase):
         cfg.CONF.set_override('enable_metadata_network', True)
         self._test_setup_helper(False)
 
-    def test_setup_device_exists(self):
+    def test_setup_device_is_ready(self):
         self._test_setup_helper(True)
 
     def test_create_dhcp_port_raise_conflict(self):

diff --git a/neutron/tests/unit/test_linux_ip_lib.py b/neutron/tests/unit/test_linux_ip_lib.py
index 7d56c01b0f4cf713359749570571a4a6c621a917..c0ae7f4a9e12b4534cdfe51959cc87acbc01ef20 100644 (file)
--- a/neutron/tests/unit/test_linux_ip_lib.py
+++ b/neutron/tests/unit/test_linux_ip_lib.py
@@ -789,3 +789,13 @@ class TestDeviceExists(base.BaseTestCase):
             _execute.return_value = ''
             _execute.side_effect = RuntimeError
             self.assertFalse(ip_lib.device_exists('eth0'))
+
+    def test_ensure_device_is_ready(self):
+        ip_lib_mock = mock.Mock()
+        with mock.patch.object(ip_lib, 'IPDevice', return_value=ip_lib_mock):
+            self.assertTrue(ip_lib.ensure_device_is_ready("eth0"))
+            self.assertTrue(ip_lib_mock.link.set_up.called)
+            ip_lib_mock.reset_mock()
+            # device doesn't exists
+            ip_lib_mock.link.set_up.side_effect = RuntimeError
+            self.assertFalse(ip_lib.ensure_device_is_ready("eth0"))