#! /usr/bin/python3

# SPDX-License-Identifier: GPL-2.0-or-later
#
# tasst - Test A Simple Socket Transport
#         library of test helpers for passt & pasta
#
# tasst/dhcp.py - Helpers for testing DHCP
#
# Copyright Red Hat
# Author: David Gibson <david@gibson.dropbear.id.au>

import ipaddress
import os

from tasst import Tasst, TasstSubData
from tasst.address import IpiAllocator, TEST_NET_1
from tasst.nstool import UnshareSite


class BaseDhcpTasst(Tasst):
    """
    Test DHCP behaviour.

    :avocado: disable
    """

    DHCLIENT = '/sbin/dhclient'

    def subsetup(self, site, ifname, addr, gw, mtu):
        site.require_cmds(self.DHCLIENT)

        pidfile = os.path.join(self.workdir, 'dhclient.pid')
        leasefile = os.path.join(self.workdir, 'dhclient.leases')

        # We need '-nc' because we may be running with capabilities
        # but not UID 0.  Without -nc dhclient drops capabilities
        # before invoking dhclient-script, so it's unable to actually
        # configure the interface
        site.fg('{} -4 -v -nc -pf {} -lf {} {}'
                .format(self.DHCLIENT, pidfile, leasefile, ifname), sudo=True)

        Tasst.subsetup(self, BaseDhcpTasst,
                       TasstSubData(site=site, ifname=ifname, addr=addr, gw=gw, mtu=mtu))

    def test_addr(self):
        sub = self.get_subsetup(BaseDhcpTasst)
        (addr,) = sub.site.addrs(sub.ifname, family='inet', scope='global')
        self.assertEquals(addr.ip, sub.addr)

    def test_route(self):
        sub = self.get_subsetup(BaseDhcpTasst)
        (defroute,) = sub.site.routes4(dst='default')
        self.assertEquals(ipaddress.ip_address(defroute['gateway']), sub.gw)

    def test_mtu(self):
        sub = self.get_subsetup(BaseDhcpTasst)
        self.assertEquals(sub.site.mtu(sub.ifname), sub.mtu)


class MetaDhcpTasst(BaseDhcpTasst):
    """Ugly workaround for
    https://github.com/avocado-framework/avocado/issues/5680.
    Explicitly apply the "meta" tag to inherited tests

    :avocado: disable
    :avocado: tags=meta

    """

    def test_addr(self):
        super().test_addr()

    def test_route(self):
        super().test_route()

    def test_mtu(self):
        super().test_mtu()


class DhcpdTasst(MetaDhcpTasst):
    DHCPD = 'dhcpd'
    SUBNET = TEST_NET_1

    def setUp(self):
        super().setUp()

        ifname = 'clientif'
        server_ifname = 'serverif'

        self.client = UnshareSite(self.__class__.__name__ + '.client', '-Un')
        self.server = UnshareSite(self.__class__.__name__ + '.server', '-n',
                                  parent=self.client, sudo=True)

        self.server.require_cmds(self.DHCPD)

        self.client.veth(ifname, server_ifname, self.server)

        # Configure the DHCP server
        ipa = IpiAllocator(self.SUBNET)
        (server_ip4,) = ipa.next_ipis()
        (client_ip4,) = ipa.next_ipis()

        confpath = os.path.join(self.workdir, 'dhcpd.conf')
        open(confpath, 'w').write('''
        subnet {} netmask {} {{
            option routers {};
            range {} {};
        }}
        '''.format(self.SUBNET.network_address, self.SUBNET.netmask,
                   server_ip4.ip, client_ip4.ip, client_ip4.ip))
        self.pidpath = os.path.join(self.workdir, 'dhcpd.pid')
        leasepath = os.path.join(self.workdir, 'dhcpd.leases')
        open(leasepath, 'w').write('')

        self.server.ifup('lo')
        self.server.ifup(server_ifname, server_ip4)

        opts = ('-f -d -4 -cf {} -lf {} -pf {}'.format(confpath, leasepath, self.pidpath))
        self.server.fg('{} -t {}'.format(self.DHCPD, opts)) # test config
        self.dhcpd = self.server.bg('{} {}'.format(self.DHCPD, opts), sudo=True)

        # Configure the client
        self.client.ifup('lo')
        BaseDhcpTasst.subsetup(self, self.client, ifname, client_ip4.ip, server_ip4.ip, 1500)

    def tearDown(self):
        pid = int(open(self.pidpath).read())
        self.server.fg('kill {}'.format(pid))
        status = self.dhcpd.wait()
        self.server.close()
        self.client.close()
        super().tearDown()