#!/usr/bin/python
# -*- coding: utf-8 -*-
#
# rtnl-link-event.py -- listen for and report link events
# Copyright 2011,2015 Sean Robinson <robinson@tuxfamily.org>
#
# This file is part of the pymnl package, a Python interface
# for netlink sockets.
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#

from __future__ import print_function

import pymnl
from pymnl.message import Payload
from pymnl.nlsocket import Socket

import if_
import if_link

# add a name for the multicast group on which to listen
RTMGRP_LINK = 1

# init and bind netlink socket
sock = Socket(pymnl.NETLINK_ROUTE)
sock.bind(pymnl.nlsocket.SOCKET_AUTOPID, RTMGRP_LINK)

try:
    while (True):
        # read returned message from netlink
        return_msg = sock.recv()

        # process the messages returned
        for msg in return_msg:
            if (msg.get_errno()):
                # tell the user what error occurred
                print("error:", msg.get_errstr())
            else:
                # use the payload data to create interface info message
                ifm = if_.IfInfoMessage(msg.get_payload().get_binary())
                # begin output line with interface info
                line = ("index=%d type=%d flags=%d family=%d " %
                        (ifm.index, ifm.type_, ifm.flags, ifm.family))

                # add running status to output line
                if (ifm.flags & if_.IFF_RUNNING):
                    line = line + "[RUNNING] "
                else:
                    line = line + "[NOT RUNNING] "

                ifla_parser = if_link.IFLAttrParser()
                # make a payload with the interface link attributes data
                ifla_payload = Payload(
                    msg.get_payload().get_binary()[len(ifm):])
                # parse the new payload into a dict of Attrs
                attrs = ifla_parser.parse(ifla_payload)

                # add final interface info to output line
                line = line + ("mtu=%d name=%s " %
                               (attrs['mtu'], attrs['ifname']))

                # finally output the dang line
                print(line)
except KeyboardInterrupt:
    sock.close()
