/cloudinit/sources/helpers/tests/test_netlink.py

# Author: Tamilmani Manoharan <tamanoha@microsoft.com>
#
# This file is part of cloud-init. See LICENSE file for license information.

from cloudinit.tests.helpers import CiTestCase, mock
import socket
import struct
import codecs
from cloudinit.sources.helpers.netlink import (
    NetlinkCreateSocketError, create_bound_netlink_socket, read_netlink_socket,
    read_rta_oper_state, unpack_rta_attr, wait_for_media_disconnect_connect,
    OPER_DOWN, OPER_UP, OPER_DORMANT, OPER_LOWERLAYERDOWN, OPER_NOTPRESENT,
    OPER_TESTING, OPER_UNKNOWN, RTATTR_START_OFFSET, RTM_NEWLINK, RTM_SETLINK,
    RTM_GETLINK, MAX_SIZE)


def int_to_bytes(i):
    '''convert integer to binary: eg: 1 to \x01'''
    hex_value = '{0:x}'.format(i)
    hex_value = '0' * (len(hex_value) % 2) + hex_value
    return codecs.decode(hex_value, 'hex_codec')


class TestCreateBoundNetlinkSocket(CiTestCase):

    @mock.patch('cloudinit.sources.helpers.netlink.socket.socket')
    def test_socket_error_on_create(self, m_socket):
        '''create_bound_netlink_socket catches socket creation exception'''

        """NetlinkCreateSocketError is raised when socket creation errors."""
        m_socket.side_effect = socket.error("Fake socket failure")
        with self.assertRaises(NetlinkCreateSocketError) as ctx_mgr:
            create_bound_netlink_socket()
        self.assertEqual(
            'Exception during netlink socket create: Fake socket failure',
            str(ctx_mgr.exception))


class TestReadNetlinkSocket(CiTestCase):

    @mock.patch('cloudinit.sources.helpers.netlink.socket.socket')
    @mock.patch('cloudinit.sources.helpers.netlink.select.select')
    def test_read_netlink_socket(self, m_select, m_socket):
        '''read_netlink_socket able to receive data'''
        data = 'netlinktest'
        m_select.return_value = [m_socket], None, None
        m_socket.recv.return_value = data
        recv_data = read_netlink_socket(m_socket, 2)
        m_select.assert_called_with([m_socket], [], [], 2)
        m_socket.recv.assert_called_with(MAX_SIZE)
        self.assertIsNotNone(recv_data)
        self.assertEqual(recv_data, data)

    @mock.patch('cloudinit.sources.helpers.netlink.socket.socket')
    @mock.patch('cloudinit.sources.helpers.netlink.select.select')
    def test_netlink_read_timeout(self, m_select, m_socket):
        '''read_netlink_socket should timeout if nothing to read'''
        m_select.return_value = [], None, None
        data = read_netlink_socket(m_socket, 1)
        m_select.assert_called_with([m_socket], [], [], 1)
        self.assertEqual(m_socket.recv.call_count, 0)
        self.assertIsNone(data)

    def test_read_invalid_socket(self):
        '''read_netlink_socket raises assert error if socket is invalid'''
        socket = None
        with self.assertRaises(AssertionError) as context:
            read_netlink_socket(socket, 1)
        self.assertTrue('netlink socket is none' in str(context.exception))


class TestParseNetlinkMessage(CiTestCase):

    def test_read_rta_oper_state(self):
        '''read_rta_oper_state could parse netlink message and extract data'''
        ifname = "eth0"
        bytes = ifname.encode("utf-8")
        buf = bytearray(48)
        struct.pack_into("HH4sHHc", buf, RTATTR_START_OFFSET, 8, 3, bytes, 5,
                         16, int_to_bytes(OPER_DOWN))
        interface_state = read_rta_oper_state(buf)
        self.assertEqual(interface_state.ifname, ifname)
        self.assertEqual(interface_state.operstate, OPER_DOWN)

    def test_read_none_data(self):
        '''read_rta_oper_state raises assert error if data is none'''
        data = None
        with self.assertRaises(AssertionError) as context:
            read_rta_oper_state(data)
        self.assertTrue('data is none', str(context.exception))

    def test_read_invalid_rta_operstate_none(self):
        '''read_rta_oper_state returns none if operstate is none'''
        ifname = "eth0"
        buf = bytearray(40)
        bytes = ifname.encode("utf-8")
        struct.pack_into("HH4s", buf, RTATTR_START_OFFSET, 8, 3, bytes)
        interface_state = read_rta_oper_state(buf)
        self.assertIsNone(interface_state)

    def test_read_invalid_rta_ifname_none(self):
        '''read_rta_oper_state returns none if ifname is none'''
        buf = bytearray(40)
        struct.pack_into("HHc", buf, RTATTR_START_OFFSET, 5, 16,
                         int_to_bytes(OPER_DOWN))
        interface_state = read_rta_oper_state(buf)
        self.assertIsNone(interface_state)

    def test_read_invalid_data_len(self):
        '''raise assert error if data size is smaller than required size'''
        buf = bytearray(32)
        with self.assertRaises(AssertionError) as context:
            read_rta_oper_state(buf)
        self.assertTrue('length of data is smaller than RTATTR_START_OFFSET' in
                        str(context.exception))

    def test_unpack_rta_attr_none_data(self):
        '''unpack_rta_attr raises assert error if data is none'''
        data = None
        with self.assertRaises(AssertionError) as context:
            unpack_rta_attr(data, RTATTR_START_OFFSET)
        self.assertTrue('data is none' in str(context.exception))

    def test_unpack_rta_attr_invalid_offset(self):
        '''unpack_rta_attr raises assert error if offset is invalid'''
        data = bytearray(48)
        with self.assertRaises(AssertionError) as context:
            unpack_rta_attr(data, "offset")
        self.assertTrue('offset is not integer' in str(context.exception))
        with self.assertRaises(AssertionError) as context:
            unpack_rta_attr(data, 31)
        self.assertTrue('rta offset is less than expected length' in
                        str(context.exception))


@mock.patch('cloudinit.sources.helpers.netlink.socket.socket')
@mock.patch('cloudinit.sources.helpers.netlink.read_netlink_socket')
class TestWaitForMediaDisconnectConnect(CiTestCase):
    with_logs = True

    def _media_switch_data(self, ifname, msg_type, operstate):
        '''construct netlink data with specified fields'''
        if ifname and operstate is not None:
            data = bytearray(48)
            bytes = ifname.encode("utf-8")
            struct.pack_into("HH4sHHc", data, RTATTR_START_OFFSET, 8, 3,
                             bytes, 5, 16, int_to_bytes(operstate))
        elif ifname:
            data = bytearray(40)
            bytes = ifname.encode("utf-8")
            struct.pack_into("HH4s", data, RTATTR_START_OFFSET, 8, 3, bytes)
        elif operstate:
            data = bytearray(40)
            struct.pack_into("HHc", data, RTATTR_START_OFFSET, 5, 16,
                             int_to_bytes(operstate))
        struct.pack_into("=LHHLL", data, 0, len(data), msg_type, 0, 0, 0)
        return data

    def test_media_down_up_scenario(self, m_read_netlink_socket,
                                    m_socket):
        '''Test for media down up sequence for required interface name'''
        ifname = "eth0"
        # construct data for Oper State down
        data_op_down = self._media_switch_data(ifname, RTM_NEWLINK, OPER_DOWN)
        # construct data for Oper State up
        data_op_up = self._media_switch_data(ifname, RTM_NEWLINK, OPER_UP)
        m_read_netlink_socket.side_effect = [data_op_down, data_op_up]
        wait_for_media_disconnect_connect(m_socket, ifname)
        self.assertEqual(m_read_netlink_socket.call_count, 2)

    def test_wait_for_media_switch_diff_interface(self, m_read_netlink_socket,
                                                  m_socket):
        '''wait_for_media_disconnect_connect ignores unexpected interfaces.

        The first two messages are for other interfaces and last two are for
        expected interface. So the function exit only after receiving last
        2 messages and therefore the call count for m_read_netlink_socket
        has to be 4
        '''
        other_ifname = "eth1"
        expected_ifname = "eth0"
        data_op_down_eth1 = self._media_switch_data(
                                other_ifname, RTM_NEWLINK, OPER_DOWN)
        data_op_up_eth1 = self._media_switch_data(
                                other_ifname, RTM_NEWLINK, OPER_UP)
        data_op_down_eth0 = self._media_switch_data(
                                expected_ifname, RTM_NEWLINK, OPER_DOWN)
        data_op_up_eth0 = self._media_switch_data(
                                expected_ifname, RTM_NEWLINK, OPER_UP)
        m_read_netlink_socket.side_effect = [data_op_down_eth1,
                                             data_op_up_eth1,
                                             data_op_down_eth0,
                                             data_op_up_eth0]
        wait_for_media_disconnect_connect(m_socket, expected_ifname)
        self.assertIn('Ignored netlink event on interface %s' % other_ifname,
                      self.logs.getvalue())
        self.assertEqual(m_read_netlink_socket.call_count, 4)

    def test_invalid_msgtype_getlink(self, m_read_netlink_socket, m_socket):
        '''wait_for_media_disconnect_connect ignores GETLINK events.

        The first two messages are for oper down and up for RTM_GETLINK type
        which netlink module will ignore. The last 2 messages are RTM_NEWLINK
        with oper state down and up messages. Therefore the call count for
        m_read_netlink_socket has to be 4 ignoring first 2 messages
        of RTM_GETLINK
        '''
        ifname = "eth0"
        data_getlink_down = self._media_switch_data(
                                    ifname, RTM_GETLINK, OPER_DOWN)
        data_getlink_up = self._media_switch_data(
                                    ifname, RTM_GETLINK, OPER_UP)
        data_newlink_down = self._media_switch_data(
                                    ifname, RTM_NEWLINK, OPER_DOWN)
        data_newlink_up = self._media_switch_data(
                                    ifname, RTM_NEWLINK, OPER_UP)
        m_read_netlink_socket.side_effect = [data_getlink_down,
                                             data_getlink_up,
                                             data_newlink_down,
                                             data_newlink_up]
        wait_for_media_disconnect_connect(m_socket, ifname)
        self.assertEqual(m_read_netlink_socket.call_count, 4)

    def test_invalid_msgtype_setlink(self, m_read_netlink_socket, m_socket):
        '''wait_for_media_disconnect_connect ignores SETLINK events.

        The first two messages are for oper down and up for RTM_GETLINK type
        which it will ignore. 3rd and 4th messages are RTM_NEWLINK with down
        and up messages. This function should exit after 4th messages since it
        sees down->up scenario. So the call count for m_read_netlink_socket
        has to be 4 ignoring first 2 messages of RTM_GETLINK and
        last 2 messages of RTM_NEWLINK
        '''
        ifname = "eth0"
        data_setlink_down = self._media_switch_data(
                                    ifname, RTM_SETLINK, OPER_DOWN)
        data_setlink_up = self._media_switch_data(
                                    ifname, RTM_SETLINK, OPER_UP)
        data_newlink_down = self._media_switch_data(
                                    ifname, RTM_NEWLINK, OPER_DOWN)
        data_newlink_up = self._media_switch_data(
                                    ifname, RTM_NEWLINK, OPER_UP)
        m_read_netlink_socket.side_effect = [data_setlink_down,
                                             data_setlink_up,
                                             data_newlink_down,
                                             data_newlink_up,
                                             data_newlink_down,
                                             data_newlink_up]
        wait_for_media_disconnect_connect(m_socket, ifname)
        self.assertEqual(m_read_netlink_socket.call_count, 4)

    def test_netlink_invalid_switch_scenario(self, m_read_netlink_socket,
                                             m_socket):
        '''returns only if it receives UP event after a DOWN event'''
        ifname = "eth0"
        data_op_down = self._media_switch_data(ifname, RTM_NEWLINK, OPER_DOWN)
        data_op_up = self._media_switch_data(ifname, RTM_NEWLINK, OPER_UP)
        data_op_dormant = self._media_switch_data(ifname, RTM_NEWLINK,
                                                  OPER_DORMANT)
        data_op_notpresent = self._media_switch_data(ifname, RTM_NEWLINK,
                                                     OPER_NOTPRESENT)
        data_op_lowerdown = self._media_switch_data(ifname, RTM_NEWLINK,
                                                    OPER_LOWERLAYERDOWN)
        data_op_testing = self._media_switch_data(ifname, RTM_NEWLINK,
                                                  OPER_TESTING)
        data_op_unknown = self._media_switch_data(ifname, RTM_NEWLINK,
                                                  OPER_UNKNOWN)
        m_read_netlink_socket.side_effect = [data_op_up, data_op_up,
                                             data_op_dormant, data_op_up,
                                             data_op_notpresent, data_op_up,
                                             data_op_lowerdown, data_op_up,
                                             data_op_testing, data_op_up,
                                             data_op_unknown, data_op_up,
                                             data_op_down, data_op_up]
        wait_for_media_disconnect_connect(m_socket, ifname)
        self.assertEqual(m_read_netlink_socket.call_count, 14)

    def test_netlink_valid_inbetween_transitions(self, m_read_netlink_socket,
                                                 m_socket):
        '''wait_for_media_disconnect_connect handles in between transitions'''
        ifname = "eth0"
        data_op_down = self._media_switch_data(ifname, RTM_NEWLINK, OPER_DOWN)
        data_op_up = self._media_switch_data(ifname, RTM_NEWLINK, OPER_UP)
        data_op_dormant = self._media_switch_data(ifname, RTM_NEWLINK,
                                                  OPER_DORMANT)
        data_op_unknown = self._media_switch_data(ifname, RTM_NEWLINK,
                                                  OPER_UNKNOWN)
        m_read_netlink_socket.side_effect = [data_op_down, data_op_dormant,
                                             data_op_unknown, data_op_up]
        wait_for_media_disconnect_connect(m_socket, ifname)
        self.assertEqual(m_read_netlink_socket.call_count, 4)

    def test_netlink_invalid_operstate(self, m_read_netlink_socket, m_socket):
        '''wait_for_media_disconnect_connect should handle invalid operstates.

        The function should not fail and return even if it receives invalid
        operstates. It always should wait for down up sequence.
        '''
        ifname = "eth0"
        data_op_down = self._media_switch_data(ifname, RTM_NEWLINK, OPER_DOWN)
        data_op_up = self._media_switch_data(ifname, RTM_NEWLINK, OPER_UP)
        data_op_invalid = self._media_switch_data(ifname, RTM_NEWLINK, 7)
        m_read_netlink_socket.side_effect = [data_op_invalid, data_op_up,
                                             data_op_down, data_op_invalid,
                                             data_op_up]
        wait_for_media_disconnect_connect(m_socket, ifname)
        self.assertEqual(m_read_netlink_socket.call_count, 5)

    def test_wait_invalid_socket(self, m_read_netlink_socket, m_socket):
        '''wait_for_media_disconnect_connect handle none netlink socket.'''
        socket = None
        ifname = "eth0"
        with self.assertRaises(AssertionError) as context:
            wait_for_media_disconnect_connect(socket, ifname)
        self.assertTrue('netlink socket is none' in str(context.exception))

    def test_wait_invalid_ifname(self, m_read_netlink_socket, m_socket):
        '''wait_for_media_disconnect_connect handle none interface name'''
        ifname = None
        with self.assertRaises(AssertionError) as context:
            wait_for_media_disconnect_connect(m_socket, ifname)
        self.assertTrue('interface name is none' in str(context.exception))
        ifname = ""
        with self.assertRaises(AssertionError) as context:
            wait_for_media_disconnect_connect(m_socket, ifname)
        self.assertTrue('interface name cannot be empty' in
                        str(context.exception))

    def test_wait_invalid_rta_attr(self, m_read_netlink_socket, m_socket):
        ''' wait_for_media_disconnect_connect handles invalid rta data'''
        ifname = "eth0"
        data_invalid1 = self._media_switch_data(None, RTM_NEWLINK, OPER_DOWN)
        data_invalid2 = self._media_switch_data(ifname, RTM_NEWLINK, None)
        data_op_down = self._media_switch_data(ifname, RTM_NEWLINK, OPER_DOWN)
        data_op_up = self._media_switch_data(ifname, RTM_NEWLINK, OPER_UP)
        m_read_netlink_socket.side_effect = [data_invalid1, data_invalid2,
                                             data_op_down, data_op_up]
        wait_for_media_disconnect_connect(m_socket, ifname)
        self.assertEqual(m_read_netlink_socket.call_count, 4)

    def test_read_multiple_netlink_msgs(self, m_read_netlink_socket, m_socket):
        '''Read multiple messages in single receive call'''
        ifname = "eth0"
        bytes = ifname.encode("utf-8")
        data = bytearray(96)
        struct.pack_into("=LHHLL", data, 0, 48, RTM_NEWLINK, 0, 0, 0)
        struct.pack_into("HH4sHHc", data, RTATTR_START_OFFSET, 8, 3,
                         bytes, 5, 16, int_to_bytes(OPER_DOWN))
        struct.pack_into("=LHHLL", data, 48, 48, RTM_NEWLINK, 0, 0, 0)
        struct.pack_into("HH4sHHc", data, 48 + RTATTR_START_OFFSET, 8,
                         3, bytes, 5, 16, int_to_bytes(OPER_UP))
        m_read_netlink_socket.return_value = data
        wait_for_media_disconnect_connect(m_socket, ifname)
        self.assertEqual(m_read_netlink_socket.call_count, 1)

    def test_read_partial_netlink_msgs(self, m_read_netlink_socket, m_socket):
        '''Read partial messages in receive call'''
        ifname = "eth0"
        bytes = ifname.encode("utf-8")
        data1 = bytearray(112)
        data2 = bytearray(32)
        struct.pack_into("=LHHLL", data1, 0, 48, RTM_NEWLINK, 0, 0, 0)
        struct.pack_into("HH4sHHc", data1, RTATTR_START_OFFSET, 8, 3,
                         bytes, 5, 16, int_to_bytes(OPER_DOWN))
        struct.pack_into("=LHHLL", data1, 48, 48, RTM_NEWLINK, 0, 0, 0)
        struct.pack_into("HH4sHHc", data1, 80, 8, 3, bytes, 5, 16,
                         int_to_bytes(OPER_DOWN))
        struct.pack_into("=LHHLL", data1, 96, 48, RTM_NEWLINK, 0, 0, 0)
        struct.pack_into("HH4sHHc", data2, 16, 8, 3, bytes, 5, 16,
                         int_to_bytes(OPER_UP))
        m_read_netlink_socket.side_effect = [data1, data2]
        wait_for_media_disconnect_connect(m_socket, ifname)
        self.assertEqual(m_read_netlink_socket.call_count, 2)