# Copyright (c) 2015 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.


from autotest_lib.client.common_lib import error
from autotest_lib.client.common_lib.cros.network import interface
from autotest_lib.client.cros import dhcp_handling_rule
from autotest_lib.client.cros import dhcp_packet
from autotest_lib.client.cros import dhcp_test_base
from autotest_lib.client.cros.networking import shill_proxy

# Length of time the lease from the DHCP server is valid.
LEASE_TIME_SECONDS = 60
# We'll fill in the subnet and give this address to the client.
INTENDED_IP_SUFFIX = "0.0.0.101"
# We should be able to complete a DHCP negotiation in this amount of time.
DHCP_NEGOTIATION_TIMEOUT_SECONDS = 10

class network_DhcpMTU(dhcp_test_base.DhcpTestBase):
    """Test implemenation of MTU including confirming the interface state."""

    def check_mtu_config(self, mtu):
        """Check that the ipconfig and interface in the client has correct MTU.

        @param mtu int expected MTU value.

        """
        proxy = shill_proxy.ShillProxy()
        device = proxy.find_object(
                'Device',
                {'Name': self.ethernet_pair.peer_interface_name})
        if device is None:
            raise error.TestFail('Device was not found.')
        device_properties = device.GetProperties(utf8_strings=True)
        ipconfig_path = device_properties['IPConfigs'][0]
        ipconfig = proxy.get_dbus_object('org.chromium.flimflam.IPConfig',
                                         ipconfig_path)
        ipconfig_properties = ipconfig.GetProperties(utf8_strings=True)
        ipconfig_mtu = ipconfig_properties['Mtu']
        if ipconfig_mtu != mtu:
            raise error.TestFail('Shill MTU %d does not match expected %d.' %
                                 (ipconfig_mtu, mtu))

        interface_mtu = interface.Interface(
                self.ethernet_pair.peer_interface_name).mtu
        if interface_mtu != mtu:
            raise error.TestFail('Interface MTU %d does not match '
                                 'expected %d.' % (interface_mtu, ipconfig_mtu))

    def test_body(self):
        """Main body of the test."""
        subnet_mask = self.ethernet_pair.interface_subnet_mask
        intended_ip = dhcp_test_base.DhcpTestBase.rewrite_ip_suffix(
                subnet_mask,
                self.server_ip,
                INTENDED_IP_SUFFIX)
        # Two real name servers, and a bogus one to be unpredictable.
        dns_servers = ["8.8.8.8", "8.8.4.4", "192.168.87.88"]
        interface_mtu = 1234
        # This is the pool of information the server will give out to the client
        # upon request.
        dhcp_options = {
                dhcp_packet.OPTION_SERVER_ID : self.server_ip,
                dhcp_packet.OPTION_SUBNET_MASK : subnet_mask,
                dhcp_packet.OPTION_IP_LEASE_TIME : LEASE_TIME_SECONDS,
                dhcp_packet.OPTION_REQUESTED_IP : intended_ip,
                dhcp_packet.OPTION_DNS_SERVERS : dns_servers,
                dhcp_packet.OPTION_INTERFACE_MTU : interface_mtu
                }
        rules = [
                dhcp_handling_rule.DhcpHandlingRule_RespondToDiscovery(
                        intended_ip, self.server_ip, dhcp_options, {}),
                dhcp_handling_rule.DhcpHandlingRule_RespondToRequest(
                        intended_ip, self.server_ip, dhcp_options, {})
                ]
        rules[-1].is_final_handler = True
        self.server.start_test(rules, DHCP_NEGOTIATION_TIMEOUT_SECONDS)
        self.server.wait_for_test_to_finish()
        if not self.server.last_test_passed:
            raise error.TestFail("Test server didn't get all the messages it "
                                 "was told to expect during negotiation.")

        self.wait_for_dhcp_propagation()
        self.check_mtu_config(interface_mtu)