Use information from the dnsmasq hosts file to call dhcp_release
Certain situations can cause the DHCP agent's local cache to get out of sync with the leases held internally by dnsmasq. This method of detecting when to call dhcp_release is idempotent and not dependent on the cache. It is more robust. Change-Id: I4eafd9cfb94a77a2f0229f89de5483dad23725cf Closes-Bug: #1250644
This commit is contained in:
Carl Baldwin
Gerrit Code Review
parent
d586a957df
commit
cfe560864f
@ -380,15 +380,17 @@ class Dnsmasq(DhcpLocalProcess):
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utils.execute(cmd, self.root_helper)
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def release_lease(self, mac_address, removed_ips):
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pass
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def _release_lease(self, mac_address, ip):
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"""Release a DHCP lease."""
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for ip in removed_ips or []:
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cmd = ['dhcp_release', self.interface_name, ip, mac_address]
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if self.network.namespace:
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ip_wrapper = ip_lib.IPWrapper(self.root_helper,
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self.network.namespace)
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ip_wrapper.netns.execute(cmd)
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else:
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utils.execute(cmd, self.root_helper)
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cmd = ['dhcp_release', self.interface_name, ip, mac_address]
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if self.network.namespace:
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ip_wrapper = ip_lib.IPWrapper(self.root_helper,
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self.network.namespace)
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ip_wrapper.netns.execute(cmd)
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else:
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utils.execute(cmd, self.root_helper)
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def reload_allocations(self):
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"""Rebuild the dnsmasq config and signal the dnsmasq to reload."""
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@ -400,6 +402,7 @@ class Dnsmasq(DhcpLocalProcess):
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'turned off DHCP: %s'), self.network.id)
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return
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self._release_unused_leases()
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self._output_hosts_file()
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self._output_opts_file()
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if self.active:
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@ -435,6 +438,27 @@ class Dnsmasq(DhcpLocalProcess):
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utils.replace_file(name, buf.getvalue())
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return name
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def _read_hosts_file_leases(self, filename):
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leases = set()
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if os.path.exists(filename):
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with open(filename) as f:
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for l in f.readlines():
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host = l.strip().split(',')
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leases.add((host[2], host[0]))
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return leases
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def _release_unused_leases(self):
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filename = self.get_conf_file_name('host')
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old_leases = self._read_hosts_file_leases(filename)
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new_leases = set()
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for port in self.network.ports:
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for alloc in port.fixed_ips:
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new_leases.add((alloc.ip_address, port.mac_address))
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for ip, mac in old_leases - new_leases:
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self._release_lease(mac, ip)
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def _output_opts_file(self):
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"""Write a dnsmasq compatible options file."""
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@ -780,16 +780,6 @@ tag:tag0,option:router,192.168.1.1""".lstrip()
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self.safe.assert_called_once_with('/foo/opts', expected)
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def test_release_lease(self):
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dm = dhcp.Dnsmasq(self.conf, FakeDualNetwork(), version=float(2.59))
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dm.release_lease(mac_address=FakePort2.mac_address,
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removed_ips=[FakePort2.fixed_ips[0].ip_address])
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exp_args = ['ip', 'netns', 'exec', 'qdhcp-ns', 'dhcp_release',
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dm.interface_name, FakePort2.fixed_ips[0].ip_address,
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FakePort2.mac_address]
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self.execute.assert_called_once_with(exp_args, root_helper='sudo',
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check_exit_code=True)
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def test_output_opts_file_pxe_2port_1net(self):
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expected = """
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tag:tag0,option:dns-server,8.8.8.8
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@ -985,6 +975,62 @@ tag:tag1,249,%s,%s""".lstrip() % (fake_v6,
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mock.call(exp_opt_name, exp_opt_data)])
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mock_open.assert_called_once_with('/proc/5/cmdline', 'r')
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def test_release_unused_leases(self):
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dnsmasq = dhcp.Dnsmasq(self.conf, FakeDualNetwork())
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ip1 = '192.168.1.2'
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mac1 = '00:00:80:aa:bb:cc'
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ip2 = '192.168.1.3'
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mac2 = '00:00:80:cc:bb:aa'
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old_leases = set([(ip1, mac1), (ip2, mac2)])
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dnsmasq._read_hosts_file_leases = mock.Mock(return_value=old_leases)
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dnsmasq._output_hosts_file = mock.Mock()
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dnsmasq._release_lease = mock.Mock()
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dnsmasq.network.ports = []
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dnsmasq._release_unused_leases()
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dnsmasq._release_lease.assert_has_calls([mock.call(mac1, ip1),
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mock.call(mac2, ip2)],
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any_order=True)
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def test_release_unused_leases_one_lease(self):
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dnsmasq = dhcp.Dnsmasq(self.conf, FakeDualNetwork())
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ip1 = '192.168.0.2'
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mac1 = '00:00:80:aa:bb:cc'
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ip2 = '192.168.0.3'
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mac2 = '00:00:80:cc:bb:aa'
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old_leases = set([(ip1, mac1), (ip2, mac2)])
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dnsmasq._read_hosts_file_leases = mock.Mock(return_value=old_leases)
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dnsmasq._output_hosts_file = mock.Mock()
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dnsmasq._release_lease = mock.Mock()
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dnsmasq.network.ports = [FakePort1()]
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dnsmasq._release_unused_leases()
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dnsmasq._release_lease.assert_has_calls([mock.call(mac2, ip2)],
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any_order=True)
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def test_read_hosts_file_leases(self):
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filename = '/path/to/file'
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with mock.patch('os.path.exists') as mock_exists:
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mock_exists.return_value = True
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with mock.patch('__builtin__.open') as mock_open:
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mock_open.return_value.__enter__ = lambda s: s
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mock_open.return_value.__exit__ = mock.Mock()
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lines = ["00:00:80:aa:bb:cc,inst-name,192.168.0.1"]
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mock_open.return_value.readlines.return_value = lines
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dnsmasq = dhcp.Dnsmasq(self.conf, FakeDualNetwork())
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leases = dnsmasq._read_hosts_file_leases(filename)
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self.assertEqual(set([("192.168.0.1", "00:00:80:aa:bb:cc")]), leases)
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mock_exists.assert_called_once_with(filename)
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mock_open.assert_called_once_with(filename)
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def test_make_subnet_interface_ip_map(self):
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with mock.patch('neutron.agent.linux.ip_lib.IPDevice') as ip_dev:
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ip_dev.return_value.addr.list.return_value = [
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