Add tooling to capture route table as a list of RouteEntry objects (A…

…zure#1221)

* Add method to capture route table as a list of route entry objects

* Change mocking strategy for route table

* Make get_route_table() non-static. All osutil callables must be so.

* Refactor reading the route table file itself; str, not ustr.

azurelinuxagent/common/osutil/default.py

@@ -36,6 +36,7 @@
 import azurelinuxagent.common.logger as logger
 import azurelinuxagent.common.conf as conf
 import azurelinuxagent.common.utils.fileutil as fileutil
+import azurelinuxagent.common.utils.networkutil as networkutil
 import azurelinuxagent.common.utils.shellutil as shellutil
 import azurelinuxagent.common.utils.textutil as textutil
 
@@ -761,6 +762,65 @@ def get_first_if(self):
 
  return '', ''
 
+ @staticmethod
+ def _build_route_list(proc_net_route):
+ """
+ Construct a list of network route entries
+ :param list(str) proc_net_route: List of lines in /proc/net/route, containing at least one route
+ :return: List of network route objects
+ :rtype: list(networkutil.RouteEntry)
+ """
+ idx = 0
+ column_index = {}
+ header_line = proc_net_route[0]
+ for header in filter(lambda h: len(h) > 0, header_line.split("\t")):
+ column_index[header.strip()] = idx
+ idx += 1
+ try:
+ idx_iface = column_index["Iface"]
+ idx_dest = column_index["Destination"]
+ idx_gw = column_index["Gateway"]
+ idx_flags = column_index["Flags"]
+ idx_metric = column_index["Metric"]
+ idx_mask = column_index["Mask"]
+ except KeyError:
+ msg = "/proc/net/route is missing key information; headers are [{0}]".format(header_line)
+ logger.periodic(logger.EVERY_HALF_DAY, msg)
+ return []
+
+ route_list = []
+ for entry in proc_net_route[1:]:
+ route = entry.split("\t")
+ if len(route) > 0:
+ route_obj = networkutil.RouteEntry(route[idx_iface], route[idx_dest], route[idx_gw], route[idx_mask],
+ route[idx_flags], route[idx_metric])
+ route_list.append(route_obj)
+ return route_list
+
+ def get_route_table(self):
+ """
+ Construct a list of all network routes known to this system.
+
+ :return: a list of network routes
+ :rtype: list(networkutil.RouteEntry)
+ """
+ route_list = []
+ try:
+ with open('/proc/net/route') as routing_table:
+ proc_net_route = list(map(str.strip, routing_table.readlines()))
+ except OSError as e:
+ logger.periodic(logger.EVERY_HALF_DAY, "Can't read route table. {0}", e)
+ return route_list
+
+ count = len(proc_net_route)
+
+ if count < 1:
+ logger.periodic(logger.EVERY_HALF_DAY, "/proc/net/route is missing headers")
+ elif count == 1:
+ logger.periodic(logger.EVERY_HALF_DAY, "/proc/net/route contains no routes")
+ else:
+ route_list = DefaultOSUtil._build_route_list(proc_net_route)
+ return route_list
 
  def get_primary_interface(self):
  """

azurelinuxagent/common/utils/networkutil.py

@@ -0,0 +1,58 @@
+#
+# Copyright 2018 Microsoft Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# Requires Python 2.6+ and Openssl 1.0+
+#
+
+
+class RouteEntry(object):
+ """
+ Represents a single route. The destination, gateway, and mask members are hex representations of the IPv4 address in
+ network byte order.
+ """
+ def __init__(self, interface, destination, gateway, mask, flags, metric):
+ self.interface = interface
+ self.destination = destination
+ self.gateway = gateway
+ self.mask = mask
+ self.flags = int(flags, 16)
+ self.metric = int(metric)
+
+ @staticmethod
+ def _net_hex_to_dotted_quad(value):
+ if len(value) != 8:
+ raise Exception("String to dotted quad conversion must be 8 characters")
+ octets = []
+ for idx in range(6, -2, -2):
+ octets.append(str(int(value[idx:idx+2], 16)))
+ return ".".join(octets)
+
+ def destination_quad(self):
+ return self._net_hex_to_dotted_quad(self.destination)
+
+ def gateway_quad(self):
+ return self._net_hex_to_dotted_quad(self.gateway)
+
+ def mask_quad(self):
+ return self._net_hex_to_dotted_quad(self.mask)
+
+ def __str__(self):
+ return "Iface: {0}\tDestination: {1}\tGateway: {2}\tMask: {3}\tFlags: {4}\tMetric: {5}" \
+ .format(self.interface, self.destination_quad(), self.gateway_quad(), self.mask_quad(),
+ self.flags, self.metric)
+
+ def __repr__(self):
+ return 'RouteEntry("{0}", "{1}", "{2}", "{3}", "{4}", "{5}")'\
+ .format(self.interface, self.destination, self.gateway, self.mask, self.flags, self.metric)

tests/common/osutil/test_default.py

@@ -28,6 +28,8 @@
 from tests.tools import *
 
 
+actual_get_proc_net_route = 'azurelinuxagent.common.osutil.default.DefaultOSUtil._get_proc_net_route'
+
 def fake_is_loopback(_, iface):
  return iface.startswith('lo')
 
@@ -91,6 +93,52 @@ def test_mount_dvd_failure(self, _):
  self.assertTrue(msg in ustr(ose))
  self.assertTrue(patch_run.call_count == 6)
 
+ def test_empty_proc_net_route(self):
+ routing_table = ""
+
+ mo = mock.mock_open(read_data=routing_table)
+ with patch(open_patch(), mo):
+ self.assertEqual(len(osutil.DefaultOSUtil().get_route_table()), 0)
+
+ def test_no_routes(self):
+ routing_table = 'Iface\tDestination\tGateway \tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU\tWindow\tIRTT \n'
+
+ mo = mock.mock_open(read_data=routing_table)
+ with patch(open_patch(), mo):
+ self.assertEqual(len(osutil.DefaultOSUtil().get_route_table()), 0)
+
+ def test_bogus_proc_net_route(self):
+ routing_table = 'Iface\tDestination\tGateway \tFlags\t\tUse\tMetric\t\neth0\t00000000\t00000000\t0001\t\t0\t0\n'
+
+ mo = mock.mock_open(read_data=routing_table)
+ with patch(open_patch(), mo):
+ self.assertEqual(len(osutil.DefaultOSUtil().get_route_table()), 0)
+
+ def test_valid_routes(self):
+ routing_table = \
+ 'Iface\tDestination\tGateway \tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU\tWindow\tIRTT \n' \
+ 'eth0\t00000000\tC1BB910A\t0003\t0\t0\t0\t00000000\t0\t0\t0 \n' \
+ 'eth0\tC0BB910A\t00000000\t0001\t0\t0\t0\tC0FFFFFF\t0\t0\t0 \n' \
+ 'eth0\t10813FA8\tC1BB910A\t000F\t0\t0\t0\tFFFFFFFF\t0\t0\t0 \n' \
+ 'eth0\tFEA9FEA9\tC1BB910A\t0007\t0\t0\t0\tFFFFFFFF\t0\t0\t0 \n' \
+ 'docker0\t002BA8C0\t00000000\t0001\t0\t0\t10\t00FFFFFF\t0\t0\t0 \n'
+
+ mo = mock.mock_open(read_data=routing_table)
+ with patch(open_patch(), mo):
+ route_list = osutil.DefaultOSUtil().get_route_table()
+
+ self.assertEqual(len(route_list), 5)
+ self.assertEqual(route_list[0].gateway_quad(), '10.145.187.193')
+ self.assertEqual(route_list[1].gateway_quad(), '0.0.0.0')
+ self.assertEqual(route_list[1].mask_quad(), '255.255.255.192')
+ self.assertEqual(route_list[2].destination_quad(), '168.63.129.16')
+ self.assertEqual(route_list[1].flags, 1)
+ self.assertEqual(route_list[2].flags, 15)
+ self.assertEqual(route_list[3].flags, 7)
+ self.assertEqual(route_list[3].metric, 0)
+ self.assertEqual(route_list[4].metric, 10)
+ self.assertEqual(route_list[0].interface, 'eth0')
+ self.assertEqual(route_list[4].interface, 'docker0')
 
  @patch('azurelinuxagent.common.osutil.default.DefaultOSUtil.get_primary_interface', return_value='eth0')
  @patch('azurelinuxagent.common.osutil.default.DefaultOSUtil._get_all_interfaces', return_value={'eth0':'10.0.0.1'})

tests/utils/test_network_util.py

@@ -0,0 +1,43 @@
+# Copyright 2018 Microsoft Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# Requires Python 2.6+ and Openssl 1.0+
+#
+
+import errno
+from socket import htonl
+
+
+import azurelinuxagent.common.utils.fileutil as fileutil
+import azurelinuxagent.common.utils.networkutil as networkutil
+
+
+from azurelinuxagent.common.future import ustr
+from tests.tools import *
+
+
+class TestNetworkOperations(AgentTestCase):
+ def test_route_entry(self):
+ interface = "eth0"
+ mask = "C0FFFFFF" # 255.255.255.192
+ destination = "C0BB910A" #
+ gateway = "C1BB910A"
+ flags = "1"
+ metric = "0"
+
+ expected = 'Iface: eth0\tDestination: 10.145.187.192\tGateway: 10.145.187.193\tMask: 255.255.255.192\tFlags: 1\tMetric: 0'
+
+ entry = networkutil.RouteEntry(interface, destination, gateway, mask, flags, metric)
+
+ self.assertEqual(str(entry), expected)