path: root/cloudinit/net/tests/test_dhcp.py

# This file is part of cloud-init. See LICENSE file for license information.

import os
import signal
from textwrap import dedent

from cloudinit.net.dhcp import (
    InvalidDHCPLeaseFileError, maybe_perform_dhcp_discovery,
    parse_dhcp_lease_file, dhcp_discovery, networkd_load_leases)
from cloudinit.util import ensure_file, write_file
from cloudinit.tests.helpers import (
    CiTestCase, mock, populate_dir, wrap_and_call)


class TestParseDHCPLeasesFile(CiTestCase):

    def test_parse_empty_lease_file_errors(self):
        """parse_dhcp_lease_file errors when file content is empty."""
        empty_file = self.tmp_path('leases')
        ensure_file(empty_file)
        with self.assertRaises(InvalidDHCPLeaseFileError) as context_manager:
            parse_dhcp_lease_file(empty_file)
        error = context_manager.exception
        self.assertIn('Cannot parse empty dhcp lease file', str(error))

    def test_parse_malformed_lease_file_content_errors(self):
        """parse_dhcp_lease_file errors when file content isn't dhcp leases."""
        non_lease_file = self.tmp_path('leases')
        write_file(non_lease_file, 'hi mom.')
        with self.assertRaises(InvalidDHCPLeaseFileError) as context_manager:
            parse_dhcp_lease_file(non_lease_file)
        error = context_manager.exception
        self.assertIn('Cannot parse dhcp lease file', str(error))

    def test_parse_multiple_leases(self):
        """parse_dhcp_lease_file returns a list of all leases within."""
        lease_file = self.tmp_path('leases')
        content = dedent("""
            lease {
              interface "wlp3s0";
              fixed-address 192.168.2.74;
              option subnet-mask 255.255.255.0;
              option routers 192.168.2.1;
              renew 4 2017/07/27 18:02:30;
              expire 5 2017/07/28 07:08:15;
            }
            lease {
              interface "wlp3s0";
              fixed-address 192.168.2.74;
              option subnet-mask 255.255.255.0;
              option routers 192.168.2.1;
            }
        """)
        expected = [
            {'interface': 'wlp3s0', 'fixed-address': '192.168.2.74',
             'subnet-mask': '255.255.255.0', 'routers': '192.168.2.1',
             'renew': '4 2017/07/27 18:02:30',
             'expire': '5 2017/07/28 07:08:15'},
            {'interface': 'wlp3s0', 'fixed-address': '192.168.2.74',
             'subnet-mask': '255.255.255.0', 'routers': '192.168.2.1'}]
        write_file(lease_file, content)
        self.assertItemsEqual(expected, parse_dhcp_lease_file(lease_file))


class TestDHCPDiscoveryClean(CiTestCase):
    with_logs = True

    @mock.patch('cloudinit.net.dhcp.find_fallback_nic')
    def test_no_fallback_nic_found(self, m_fallback_nic):
        """Log and do nothing when nic is absent and no fallback is found."""
        m_fallback_nic.return_value = None  # No fallback nic found
        self.assertEqual([], maybe_perform_dhcp_discovery())
        self.assertIn(
            'Skip dhcp_discovery: Unable to find fallback nic.',
            self.logs.getvalue())

    def test_provided_nic_does_not_exist(self):
        """When the provided nic doesn't exist, log a message and no-op."""
        self.assertEqual([], maybe_perform_dhcp_discovery('idontexist'))
        self.assertIn(
            'Skip dhcp_discovery: nic idontexist not found in get_devicelist.',
            self.logs.getvalue())

    @mock.patch('cloudinit.net.dhcp.util.which')
    @mock.patch('cloudinit.net.dhcp.find_fallback_nic')
    def test_absent_dhclient_command(self, m_fallback, m_which):
        """When dhclient doesn't exist in the OS, log the issue and no-op."""
        m_fallback.return_value = 'eth9'
        m_which.return_value = None  # dhclient isn't found
        self.assertEqual([], maybe_perform_dhcp_discovery())
        self.assertIn(
            'Skip dhclient configuration: No dhclient command found.',
            self.logs.getvalue())

    @mock.patch('cloudinit.temp_utils.os.getuid')
    @mock.patch('cloudinit.net.dhcp.dhcp_discovery')
    @mock.patch('cloudinit.net.dhcp.util.which')
    @mock.patch('cloudinit.net.dhcp.find_fallback_nic')
    def test_dhclient_run_with_tmpdir(self, m_fback, m_which, m_dhcp, m_uid):
        """maybe_perform_dhcp_discovery passes tmpdir to dhcp_discovery."""
        m_uid.return_value = 0  # Fake root user for tmpdir
        m_fback.return_value = 'eth9'
        m_which.return_value = '/sbin/dhclient'
        m_dhcp.return_value = {'address': '192.168.2.2'}
        retval = wrap_and_call(
            'cloudinit.temp_utils',
            {'_TMPDIR': {'new': None},
             'os.getuid': 0},
            maybe_perform_dhcp_discovery)
        self.assertEqual({'address': '192.168.2.2'}, retval)
        self.assertEqual(
            1, m_dhcp.call_count, 'dhcp_discovery not called once')
        call = m_dhcp.call_args_list[0]
        self.assertEqual('/sbin/dhclient', call[0][0])
        self.assertEqual('eth9', call[0][1])
        self.assertIn('/var/tmp/cloud-init/cloud-init-dhcp-', call[0][2])

    @mock.patch('cloudinit.net.dhcp.os.kill')
    @mock.patch('cloudinit.net.dhcp.util.subp')
    def test_dhcp_discovery_run_in_sandbox_warns_invalid_pid(self, m_subp,
                                                             m_kill):
        """dhcp_discovery logs a warning when pidfile contains invalid content.

        Lease processing still occurs and no proc kill is attempted.
        """
        tmpdir = self.tmp_dir()
        dhclient_script = os.path.join(tmpdir, 'dhclient.orig')
        script_content = '#!/bin/bash\necho fake-dhclient'
        write_file(dhclient_script, script_content, mode=0o755)
        write_file(self.tmp_path('dhclient.pid', tmpdir), '')  # Empty pid ''
        lease_content = dedent("""
            lease {
              interface "eth9";
              fixed-address 192.168.2.74;
              option subnet-mask 255.255.255.0;
              option routers 192.168.2.1;
            }
        """)
        write_file(self.tmp_path('dhcp.leases', tmpdir), lease_content)

        self.assertItemsEqual(
            [{'interface': 'eth9', 'fixed-address': '192.168.2.74',
              'subnet-mask': '255.255.255.0', 'routers': '192.168.2.1'}],
            dhcp_discovery(dhclient_script, 'eth9', tmpdir))
        self.assertIn(
            "pid file contains non-integer content ''", self.logs.getvalue())
        m_kill.assert_not_called()

    @mock.patch('cloudinit.net.dhcp.os.kill')
    @mock.patch('cloudinit.net.dhcp.util.wait_for_files')
    @mock.patch('cloudinit.net.dhcp.util.subp')
    def test_dhcp_discovery_run_in_sandbox_waits_on_lease_and_pid(self,
                                                                  m_subp,
                                                                  m_wait,
                                                                  m_kill):
        """dhcp_discovery waits for the presence of pidfile and dhcp.leases."""
        tmpdir = self.tmp_dir()
        dhclient_script = os.path.join(tmpdir, 'dhclient.orig')
        script_content = '#!/bin/bash\necho fake-dhclient'
        write_file(dhclient_script, script_content, mode=0o755)
        # Don't create pid or leases file
        pidfile = self.tmp_path('dhclient.pid', tmpdir)
        leasefile = self.tmp_path('dhcp.leases', tmpdir)
        m_wait.return_value = [pidfile]  # Return the missing pidfile wait for
        self.assertEqual([], dhcp_discovery(dhclient_script, 'eth9', tmpdir))
        self.assertEqual(
            mock.call([pidfile, leasefile], maxwait=5, naplen=0.01),
            m_wait.call_args_list[0])
        self.assertIn(
            'WARNING: dhclient did not produce expected files: dhclient.pid',
            self.logs.getvalue())
        m_kill.assert_not_called()

    @mock.patch('cloudinit.net.dhcp.os.kill')
    @mock.patch('cloudinit.net.dhcp.util.subp')
    def test_dhcp_discovery_run_in_sandbox(self, m_subp, m_kill):
        """dhcp_discovery brings up the interface and runs dhclient.

        It also returns the parsed dhcp.leases file generated in the sandbox.
        """
        tmpdir = self.tmp_dir()
        dhclient_script = os.path.join(tmpdir, 'dhclient.orig')
        script_content = '#!/bin/bash\necho fake-dhclient'
        write_file(dhclient_script, script_content, mode=0o755)
        lease_content = dedent("""
            lease {
              interface "eth9";
              fixed-address 192.168.2.74;
              option subnet-mask 255.255.255.0;
              option routers 192.168.2.1;
            }
        """)
        lease_file = os.path.join(tmpdir, 'dhcp.leases')
        write_file(lease_file, lease_content)
        pid_file = os.path.join(tmpdir, 'dhclient.pid')
        my_pid = 1
        write_file(pid_file, "%d\n" % my_pid)

        self.assertItemsEqual(
            [{'interface': 'eth9', 'fixed-address': '192.168.2.74',
              'subnet-mask': '255.255.255.0', 'routers': '192.168.2.1'}],
            dhcp_discovery(dhclient_script, 'eth9', tmpdir))
        # dhclient script got copied
        with open(os.path.join(tmpdir, 'dhclient')) as stream:
            self.assertEqual(script_content, stream.read())
        # Interface was brought up before dhclient called from sandbox
        m_subp.assert_has_calls([
            mock.call(
                ['ip', 'link', 'set', 'dev', 'eth9', 'up'], capture=True),
            mock.call(
                [os.path.join(tmpdir, 'dhclient'), '-1', '-v', '-lf',
                 lease_file, '-pf', os.path.join(tmpdir, 'dhclient.pid'),
                 'eth9', '-sf', '/bin/true'], capture=True)])
        m_kill.assert_has_calls([mock.call(my_pid, signal.SIGKILL)])


class TestSystemdParseLeases(CiTestCase):

    lxd_lease = dedent("""\
    # This is private data. Do not parse.
    ADDRESS=10.75.205.242
    NETMASK=255.255.255.0
    ROUTER=10.75.205.1
    SERVER_ADDRESS=10.75.205.1
    NEXT_SERVER=10.75.205.1
    BROADCAST=10.75.205.255
    T1=1580
    T2=2930
    LIFETIME=3600
    DNS=10.75.205.1
    DOMAINNAME=lxd
    HOSTNAME=a1
    CLIENTID=ffe617693400020000ab110c65a6a0866931c2
    """)

    lxd_parsed = {
        'ADDRESS': '10.75.205.242',
        'NETMASK': '255.255.255.0',
        'ROUTER': '10.75.205.1',
        'SERVER_ADDRESS': '10.75.205.1',
        'NEXT_SERVER': '10.75.205.1',
        'BROADCAST': '10.75.205.255',
        'T1': '1580',
        'T2': '2930',
        'LIFETIME': '3600',
        'DNS': '10.75.205.1',
        'DOMAINNAME': 'lxd',
        'HOSTNAME': 'a1',
        'CLIENTID': 'ffe617693400020000ab110c65a6a0866931c2',
    }

    azure_lease = dedent("""\
    # This is private data. Do not parse.
    ADDRESS=10.132.0.5
    NETMASK=255.255.255.255
    ROUTER=10.132.0.1
    SERVER_ADDRESS=169.254.169.254
    NEXT_SERVER=10.132.0.1
    MTU=1460
    T1=43200
    T2=75600
    LIFETIME=86400
    DNS=169.254.169.254
    NTP=169.254.169.254
    DOMAINNAME=c.ubuntu-foundations.internal
    DOMAIN_SEARCH_LIST=c.ubuntu-foundations.internal google.internal
    HOSTNAME=tribaal-test-171002-1349.c.ubuntu-foundations.internal
    ROUTES=10.132.0.1/32,0.0.0.0 0.0.0.0/0,10.132.0.1
    CLIENTID=ff405663a200020000ab11332859494d7a8b4c
    OPTION_245=624c3620
    """)

    azure_parsed = {
        'ADDRESS': '10.132.0.5',
        'NETMASK': '255.255.255.255',
        'ROUTER': '10.132.0.1',
        'SERVER_ADDRESS': '169.254.169.254',
        'NEXT_SERVER': '10.132.0.1',
        'MTU': '1460',
        'T1': '43200',
        'T2': '75600',
        'LIFETIME': '86400',
        'DNS': '169.254.169.254',
        'NTP': '169.254.169.254',
        'DOMAINNAME': 'c.ubuntu-foundations.internal',
        'DOMAIN_SEARCH_LIST': 'c.ubuntu-foundations.internal google.internal',
        'HOSTNAME': 'tribaal-test-171002-1349.c.ubuntu-foundations.internal',
        'ROUTES': '10.132.0.1/32,0.0.0.0 0.0.0.0/0,10.132.0.1',
        'CLIENTID': 'ff405663a200020000ab11332859494d7a8b4c',
        'OPTION_245': '624c3620'}

    def setUp(self):
        super(TestSystemdParseLeases, self).setUp()
        self.lease_d = self.tmp_dir()

    def test_no_leases_returns_empty_dict(self):
        """A leases dir with no lease files should return empty dictionary."""
        self.assertEqual({}, networkd_load_leases(self.lease_d))

    def test_no_leases_dir_returns_empty_dict(self):
        """A non-existing leases dir should return empty dict."""
        enodir = os.path.join(self.lease_d, 'does-not-exist')
        self.assertEqual({}, networkd_load_leases(enodir))

    def test_single_leases_file(self):
        """A leases dir with one leases file."""
        populate_dir(self.lease_d, {'2': self.lxd_lease})
        self.assertEqual(
            {'2': self.lxd_parsed}, networkd_load_leases(self.lease_d))

    def test_single_azure_leases_file(self):
        """On Azure, option 245 should be present, verify it specifically."""
        populate_dir(self.lease_d, {'1': self.azure_lease})
        self.assertEqual(
            {'1': self.azure_parsed}, networkd_load_leases(self.lease_d))

    def test_multiple_files(self):
        """Multiple leases files on azure with one found return that value."""
        self.maxDiff = None
        populate_dir(self.lease_d, {'1': self.azure_lease,
                                    '9': self.lxd_lease})
        self.assertEqual({'1': self.azure_parsed, '9': self.lxd_parsed},
                         networkd_load_leases(self.lease_d))