#
# Copyright 2016-present Ciena 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.
#
import unittest
from nose.tools import *
from nose.twistedtools import reactor, deferred
from twisted.internet import defer
from scapy.all import *
import time
import os
from DHCP import DHCPTest
from OnosCtrl import OnosCtrl
from OnosFlowCtrl import get_mac
from portmaps import g_subscriber_port_map
log.setLevel('INFO')

class dhcprelay_exchange(unittest.TestCase):

    app = 'org.onosproject.dhcprelay'
    app_dhcp = 'org.onosproject.dhcp'
    relay_device_id = 'of:' + get_mac('ovsbr0')
    relay_interface_port = 100
    relay_interfaces = (g_subscriber_port_map[relay_interface_port],)
    interface_to_mac_map = {}
    dhcp_data_dir = os.path.join(os.path.dirname(os.path.realpath(__file__)), '..', 'setup')
    default_config = { 'default-lease-time' : 600, 'max-lease-time' : 7200, }
    default_options = [ ('subnet-mask', '255.255.255.0'),
                     ('broadcast-address', '192.168.1.255'),
                     ('domain-name-servers', '192.168.1.1'),
                     ('domain-name', '"mydomain.cord-tester"'),
                   ]
    ##specify the IP for the dhcp interface matching the subnet and subnet config
    ##this is done for each interface dhcpd server would be listening on
    default_subnet_config = [ ('192.168.1.2',
'''
subnet 192.168.1.0 netmask 255.255.255.0 {
    range 192.168.1.10 192.168.1.100;
}
'''), ]

    @classmethod
    def setUpClass(cls):
        ''' Activate the dhcprelay app'''
        OnosCtrl(cls.app_dhcp).deactivate()
        time.sleep(3)
        cls.onos_ctrl = OnosCtrl(cls.app)
        status, _ = cls.onos_ctrl.activate()
        assert_equal(status, True)
        time.sleep(3)
        ##start dhcpd initially with default config
        cls.dhcpd_start()
        cls.onos_dhcp_relay_load()

    @classmethod
    def tearDownClass(cls):
        '''Deactivate the dhcp relay app'''
        try:
            os.unlink('{}/dhcpd.conf'.format(cls.dhcp_data_dir))
            os.unlink('{}/dhcpd.leases'.format(cls.dhcp_data_dir))
        except: pass
        cls.onos_ctrl.deactivate()
        cls.dhcpd_stop()

    @classmethod
    def onos_load_config(cls, config):
        status, code = OnosCtrl.config(config)
        if status is False:
            log.info('JSON request returned status %d' %code)
            assert_equal(status, True)
        time.sleep(3)

    @classmethod
    def onos_dhcp_relay_load(cls):
        relay_device_map = '{}/{}'.format(cls.relay_device_id, cls.relay_interface_port)
        dhcp_dict = {'apps':{'org.onosproject.dhcp-relay':{'dhcprelay':
                                                          {'dhcpserverConnectPoint':relay_device_map}}}}
        cls.onos_load_config(dhcp_dict)

    @classmethod
    def host_load(cls, iface):
        '''Have ONOS discover the hosts for dhcp-relay responses'''
        port = g_subscriber_port_map[iface]
        host = '173.17.1.{}'.format(port)
        cmds = ( 'ifconfig {} 0'.format(iface),
                 'ifconfig {0} {1}'.format(iface, host),
                 'arping -I {0} {1} -c 2'.format(iface, host),
                 'ifconfig {} 0'.format(iface), )
        for c in cmds:
            os.system(c)

    @classmethod
    def dhcpd_conf_generate(cls, config = default_config, options = default_options,
                            subnet = default_subnet_config):
        conf = ''
        for k, v in config.items():
            conf += '{} {};\n'.format(k, v)

        opts = ''
        for k, v in options:
            opts += 'option {} {};\n'.format(k, v)

        subnet_config = ''
        for _, v in subnet:
            subnet_config += '{}\n'.format(v)

        return '{}{}{}'.format(conf, opts, subnet_config)

    @classmethod
    def dhcpd_start(cls, intf_list = relay_interfaces,
                    config = default_config, options = default_options,
                    subnet = default_subnet_config):
        '''Start the dhcpd server by generating the conf file'''
        ##stop dhcpd if already running
        cls.dhcpd_stop()
        dhcp_conf = cls.dhcpd_conf_generate(config = config, options = options,
                                            subnet = subnet)
        ##first touch dhcpd.leases if it doesn't exist
        lease_file = '{}/dhcpd.leases'.format(cls.dhcp_data_dir)
        if os.access(lease_file, os.F_OK) is False:
            with open(lease_file, 'w') as fd: pass

        conf_file = '{}/dhcpd.conf'.format(cls.dhcp_data_dir)
        with open(conf_file, 'w') as fd:
            fd.write(dhcp_conf)

        #now configure the dhcpd interfaces for various subnets
        index = 0
        for ip,_ in subnet:
            intf = intf_list[index]
            index += 1
            os.system('ifconfig {} {}'.format(intf, ip))

        intf_str = ','.join(intf_list)
        dhcpd_cmd = '/usr/sbin/dhcpd -4 --no-pid -cf {0} -lf {1} {2}'.format(conf_file, lease_file, intf_str)
        log.info('Starting DHCPD server with command: %s' %dhcpd_cmd)
        ret = os.system(dhcpd_cmd)
        assert_equal(ret, 0)
        time.sleep(3)
        cls.relay_interfaces = intf_list

    @classmethod
    def dhcpd_stop(cls):
        os.system('pkill -9 dhcpd')
        for intf in cls.relay_interfaces:
            os.system('ifconfig {} 0'.format(intf))

    def get_mac(self, iface):
        if self.interface_to_mac_map.has_key(iface):
            return self.interface_to_mac_map[iface]
        mac = get_mac(iface, pad = 0)
        self.interface_to_mac_map[iface] = mac
        return mac

    def send_recv(self, mac, update_seed = False, validate = True):
        cip, sip = self.dhcp.discover(mac = mac, update_seed = update_seed)
        if validate:
            assert_not_equal(cip, None)
            assert_not_equal(sip, None)
            log.info('Got dhcp client IP %s from server %s for mac %s' %
                     (cip, sip, self.dhcp.get_mac(cip)[0]))
        return cip,sip

    def test_dhcp_1request(self, iface = 'veth0'):
        mac = self.get_mac(iface)
        self.host_load(iface)
        ##we use the defaults for this test that serves as an example for others
        ##You don't need to restart dhcpd server if retaining default config
        config = self.default_config
        options = self.default_options
        subnet = self.default_subnet_config
        dhcpd_interface_list = self.relay_interfaces
        self.dhcpd_start(intf_list = dhcpd_interface_list,
                         config = config,
                         options = options,
                         subnet = subnet)
        self.dhcp = DHCPTest(seed_ip = '10.10.10.1', iface = iface)
        self.send_recv(mac)