# Copyright (c) 2013 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.

import logging
import time

from autotest_lib.client.common_lib import error
from autotest_lib.client.common_lib import utils
from autotest_lib.client.cros import dhcp_test_base
from autotest_lib.client.cros import radvd_server
from autotest_lib.client.cros.networking import shill_proxy

class network_Ipv6SimpleNegotiation(dhcp_test_base.DhcpTestBase):
    """
    The test subclass that implements IPv6 negotiation.  This test
    starts an IPv6 router, then performs a series of tests on the
    IPv6 addresses and IPv6 DNS addresses that the DUT should have
    gained.
    """

    def _get_ip6_addresses(self):
        """Gets the list of client IPv6 addresses.

        Retrieve IPv6 addresses associated with the "client side" of the
        pseudo-interface pair.  Returns a dict keyed by the IPv6 address,
        with the values being the array of attribute strings that follow
        int the "ip addr show" output.  For example, a line containing:

            inet6 fe80::ae16:2dff:fe01:0203/64 scope link

        will turn into a dict key:

            'fe80::ae16:2dff:fe01:0203/64': [ 'scope', 'link' ]

        """
        addr_output = utils.system_output(
            "ip -6 addr show dev %s" % self.ethernet_pair.peer_interface_name)
        addresses = {}
        for line in addr_output.splitlines():
            parts = line.lstrip().split()
            if parts[0] != 'inet6' or 'deprecated' in parts:
                continue
            addresses[parts[1]] = parts[2:]
        return addresses


    def _get_link_address(self):
        """Get the client MAC address.

        Retrieve the MAC address associated with the "client side" of the
        pseudo-interface pair.  For example, the "ip link show" output:

            link/ether 01:02:03:04:05:05 brd ff:ff:ff:ff:ff:ff

        will cause a return of "01:02:03:04:05:05"

        """
        addr_output = utils.system_output(
            'ip link show %s' % self.ethernet_pair.peer_interface_name)
        for line in addr_output.splitlines():
            parts = line.lstrip().split(' ')
            if parts[0] == 'link/ether':
                return parts[1]


    def _get_ipconfig_properties(self):
        for ipconfig in self.get_interface_ipconfig_objects(
                self.ethernet_pair.peer_interface_name):
            ipconfig_properties = shill_proxy.ShillProxy.dbus2primitive(
                    ipconfig.GetProperties(utf8_strings=True))
            if 'Method' not in ipconfig_properties:
                continue

            if ipconfig_properties['Method'] != 'ipv6':
                continue

            return ipconfig_properties
        else:
            raise error.TestError('Found no IPv6 IPConfig entries')


    def verify_ipv6_addresses(self):
        """Verify IPv6 configuration.

        Perform various tests to validate the IPv6 addresses acquired by
        the client.

        """
        addresses = self._get_ip6_addresses()
        logging.info('Got addresses %r', addresses)
        global_addresses = [key for key in addresses
                            if 'global' in addresses[key]]

        if len(global_addresses) != 2:
            raise error.TestError('Expected 2 global address but got %d' %
                                  len(global_addresses))

        prefix = radvd_server.RADVD_DEFAULT_PREFIX
        prefix = prefix[:prefix.index('::')]
        for address in global_addresses:
            if not address.startswith(prefix):
                raise error.TestError('Global address %s does not start with '
                                      'expected prefix %s' %
                                      address, prefix)

        # One globally scoped address should be based on the last 3 octets
        # of the MAC adddress, while the other should not.  For example,
        # for MAC address "01:02:03:04:05:06", we should see an address
        # that ends with "4:506/64" (the "/64" is the default radvd suffix).
        link_parts = [int(b, 16) for b in self._get_link_address().split(':')]
        address_suffix = '%x:%x%s' % (link_parts[3],
                                      (link_parts[4] << 8) | link_parts[5],
                                      radvd_server.RADVD_DEFAULT_SUFFIX)
        mac_related_addresses = [addr for addr in global_addresses
                                 if addr.endswith(address_suffix)]
        if len(mac_related_addresses) != 1:
            raise error.TestError('Expected 1 mac-related global address but '
                                  'got %d' % len(mac_related_addresses))
        mac_related_address = mac_related_addresses[0]

        local_address_count = len(addresses) - len(global_addresses)
        if local_address_count <= 0:
            raise error.TestError('Expected at least 1 non-global address but '
                                  'got %d' % local_address_count)

        temporary_address = [addr for addr in global_addresses
                                 if addr != mac_related_address][0]
        self.verify_ipconfig_contains(temporary_address)


    def verify_ipconfig_contains(self, address_and_prefix):
        """Verify that shill has an IPConfig entry with the specified address.

        @param address_and_prefix string with address/prefix to search for.

        """
        address, prefix_str = address_and_prefix.split('/')
        prefix = int(prefix_str)
        ipconfig_properties = self._get_ipconfig_properties()

        for property, value in (('Address', address), ('Prefixlen', prefix)):
            if property not in ipconfig_properties:
               raise error.TestError('IPv6 IPConfig entry does not '
                                     'contain property %s' % property)
            if ipconfig_properties[property] != value:
               raise error.TestError('IPv6 IPConfig property %s does not '
                                     'contain the expected value %s; '
                                     'instead it is %s' %
                                     (property, value,
                                      ipconfig_properties[property]))


    def verify_ipconfig_name_servers(self, name_servers):
        """Verify that shill has an IPConfig entry with the specified name
        servers.

        @param name_servers list of expected name servers.

        """
        ipconfig_properties = self._get_ipconfig_properties()

        if ipconfig_properties['NameServers'] != name_servers:
            raise error.TestError('IPv6 name servers mismatched: '
                                  'expected %r actual %r' %
                                  name_servers,
                                  ipconfig_properties['NameServers'])


    def test_body(self):
        """The main body for this test."""
        server = radvd_server.RadvdServer(self.ethernet_pair.interface_name)
        server.start_server()

        try:
            # Wait for IPv6 negotiation to complete.
            time.sleep(radvd_server.RADVD_DEFAULT_MAX_ADV_INTERVAL)

            # In this time, we should have also acquired an IPv6 address.
            self.verify_ipv6_addresses()
            self.verify_ipconfig_name_servers(
                    radvd_server.RADVD_DEFAULT_RDNSS_SERVERS.split(' '))
        finally:
            server.stop_server()