Makes sure to recreate gateway for moved ip

If nova moves an ip when setting up dhcp, make sure to reset
the default gateway.  Fixes bug 859587

Change-Id: I9f2b7bc5ede142717df6cb1653043b4f5c09959a

2 files changed, 44 insertions, 1 deletions

diff --git a/nova/network/linux_net.py b/nova/network/linux_net.py
index 0459b4aeb..0443a9673 100755
--- a/nova/network/linux_net.py
+++ b/nova/network/linux_net.py
@@ -486,12 +486,25 @@ def initialize_gateway_device(dev, network_ref):
             if ip_params[0] != full_ip:
                 new_ip_params.append(ip_params)
     if not old_ip_params or old_ip_params[0][0] != full_ip:
+        gateway = None
+        out, err = _execute('route', '-n', run_as_root=True)
+        for line in out.split('\n'):
+            fields = line.split()
+            if fields and fields[0] == '0.0.0.0' and \
+                            fields[-1] == dev:
+                gateway = fields[1]
+                _execute('route', 'del', 'default', 'gw', gateway,
+                         'dev', dev, check_exit_code=False,
+                         run_as_root=True)
         for ip_params in old_ip_params:
             _execute(*_ip_bridge_cmd('del', ip_params, dev),
                         run_as_root=True)
         for ip_params in new_ip_params:
             _execute(*_ip_bridge_cmd('add', ip_params, dev),
                         run_as_root=True)
+        if gateway:
+            _execute('route', 'add', 'default', 'gw', gateway,
+                        run_as_root=True)
         if FLAGS.send_arp_for_ha:
             _execute('arping', '-U', network_ref['dhcp_server'],
                       '-A', '-I', dev,
diff --git a/nova/tests/test_linux_net.py b/nova/tests/test_linux_net.py
index 940af7b5f..0e933eff5 100755
--- a/nova/tests/test_linux_net.py
+++ b/nova/tests/test_linux_net.py
@@ -346,7 +346,7 @@ class LinuxNetworkTestCase(test.TestCase):
         actual = self.driver._host_dhcp(fixed_ips[0])

         self.assertEquals(actual, expected)

 

-    def _test_initialize_gateway(self, existing, expected):

+    def _test_initialize_gateway(self, existing, expected, routes=''):

         self.flags(fake_network=False)

         executes = []

 

@@ -354,6 +354,8 @@ class LinuxNetworkTestCase(test.TestCase):
             executes.append(args)

             if args[0] == 'ip' and args[1] == 'addr' and args[2] == 'show':

                 return existing, ""

+            if args[0] == 'route' and args[1] == '-n':

+                return routes, ""

         self.stubs.Set(utils, 'execute', fake_execute)

         network = {'dhcp_server': '192.168.1.1',

                    'cidr': '192.168.1.0/24',

@@ -371,6 +373,7 @@ class LinuxNetworkTestCase(test.TestCase):
             "    valid_lft forever preferred_lft forever\n")

         expected = [

             ('ip', 'addr', 'show', 'dev', 'eth0', 'scope', 'global'),

+            ('route', '-n'),

             ('ip', 'addr', 'del', '192.168.0.1/24',

              'brd', '192.168.0.255', 'scope', 'global', 'dev', 'eth0'),

             ('ip', 'addr', 'add', '192.168.1.1/24',

@@ -383,6 +386,32 @@ class LinuxNetworkTestCase(test.TestCase):
         ]

         self._test_initialize_gateway(existing, expected)

 

+    def test_initialize_gateway_resets_route(self):

+        routes = "0.0.0.0         192.68.0.1        0.0.0.0         " \

+                "UG    100    0        0 eth0"

+        existing = ("2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> "

+            "    mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000\n"

+            "    link/ether de:ad:be:ef:be:ef brd ff:ff:ff:ff:ff:ff\n"

+            "    inet 192.168.0.1/24 brd 192.168.0.255 scope global eth0\n"

+            "    inet6 dead::beef:dead:beef:dead/64 scope link\n"

+            "    valid_lft forever preferred_lft forever\n")

+        expected = [

+            ('ip', 'addr', 'show', 'dev', 'eth0', 'scope', 'global'),

+            ('route', '-n'),

+            ('route', 'del', 'default', 'gw', '192.68.0.1', 'dev', 'eth0'),

+            ('ip', 'addr', 'del', '192.168.0.1/24',

+             'brd', '192.168.0.255', 'scope', 'global', 'dev', 'eth0'),

+            ('ip', 'addr', 'add', '192.168.1.1/24',

+             'brd', '192.168.1.255', 'dev', 'eth0'),

+            ('ip', 'addr', 'add', '192.168.0.1/24',

+             'brd', '192.168.0.255', 'scope', 'global', 'dev', 'eth0'),

+            ('route', 'add', 'default', 'gw', '192.68.0.1'),

+            ('ip', '-f', 'inet6', 'addr', 'change',

+             '2001:db8::/64', 'dev', 'eth0'),

+            ('ip', 'link', 'set', 'dev', 'eth0', 'promisc', 'on'),

+        ]

+        self._test_initialize_gateway(existing, expected, routes)

+

     def test_initialize_gateway_no_move_right_ip(self):

         existing = ("2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> "

             "    mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000\n"

@@ -407,6 +436,7 @@ class LinuxNetworkTestCase(test.TestCase):
             "    valid_lft forever preferred_lft forever\n")

         expected = [

             ('ip', 'addr', 'show', 'dev', 'eth0', 'scope', 'global'),

+            ('route', '-n'),

             ('ip', 'addr', 'add', '192.168.1.1/24',

              'brd', '192.168.1.255', 'dev', 'eth0'),

             ('ip', '-f', 'inet6', 'addr', 'change',