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# Copyright (C) 2012 Aleksey Lim
#
# 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 3 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, see <http://www.gnu.org/licenses/>.
"""Linux Netlink integration."""
import os
import socket
import struct
import logging
from sugar_network.toolkit import coroutine
# RTnetlink multicast groups - backwards compatibility for userspace
RTMGRP_LINK = 1
RTMGRP_NOTIFY = 2
RTMGRP_NEIGH = 4
RTMGRP_TC = 8
RTMGRP_IPV4_IFADDR = 0x10
RTMGRP_IPV4_MROUTE = 0x20
RTMGRP_IPV4_ROUTE = 0x40
RTMGRP_IPV4_RULE = 0x80
RTMGRP_IPV6_IFADDR = 0x100
RTMGRP_IPV6_MROUTE = 0x200
RTMGRP_IPV6_ROUTE = 0x400
RTMGRP_IPV6_IFINFO = 0x800
RTMGRP_DECnet_IFADDR = 0x1000
RTMGRP_DECnet_ROUTE = 0x4000
RTMGRP_IPV6_PREFIX = 0x20000
#: Message type, Nothing
NLMSG_NOOP = 0x1
#: Message type, Error
NLMSG_ERROR = 0x2
#: Message type, End of a dump
NLMSG_DONE = 0x3
#: Message type, Data lost
NLMSG_OVERRUN = 0x4
_MESSAGE_MAX_SIZE = 16384
_logger = logging.getLogger('netlink')
def wait_for_route():
def get_route():
with file('/proc/self/net/route') as f:
# Skip header
f.readline()
while True:
line = f.readline()
if not line:
break
dst, gw = line.split('\t', 3)[1:3]
if int(dst, 16) in (0, 224):
return gw
old_route = get_route()
if old_route:
yield old_route
with Netlink(socket.NETLINK_ROUTE,
RTMGRP_IPV4_ROUTE | RTMGRP_IPV6_ROUTE) as monitor:
while True:
coroutine.select([monitor.fileno()], [], [])
while coroutine.select([monitor.fileno()], [], [], 1)[0]:
monitor.read()
new_route = get_route()
if new_route != old_route:
coroutine.reset_resolver()
yield new_route
old_route = new_route
class Netlink(object):
def __init__(self, proto, groups):
_logger.info('Start reading Netlink messages')
self._socket = socket.socket(socket.AF_NETLINK, socket.SOCK_RAW, proto)
self._socket.bind((0, groups))
def fileno(self):
if self._socket is not None:
return self._socket.fileno()
@property
def closed(self):
return self._socket is None
def close(self):
if self._socket is None:
return
self._socket.close()
self._socket = None
_logger.info('Stop reading Netlink messages')
def read(self):
if self.closed:
raise RuntimeError('Netlink is closed')
data = self._socket.recv(_MESSAGE_MAX_SIZE)
if not data:
self.close()
return
msg = Message()
__, msg.type, msg.flags, msg.seqno, msg.pid = \
struct.unpack('IHHII', data[:16])
msg.payload = data[16:]
_logger.debug('Got message: %r', msg)
if msg.type == NLMSG_ERROR:
errno = - struct.unpack('i', msg.payload[:4])[0]
if errno:
error = OSError('Netlink error, %s(%d)' %
(os.strerror(errno), errno))
error.errno = errno
raise error
return msg
def __enter__(self):
return self
def __exit__(self, exc_type, exc_value, traceback):
self.close()
class Message(object):
type = None
flags = None
seqno = 0
pid = -1
payload = None
def __repr__(self):
return '<netlink.Message type=%r flags=0x%x seqno=%r pid=%r>' % \
(self.type, self.flags, self.seqno, self.pid)
if __name__ == '__main__':
import select
logging.basicConfig(level=logging.DEBUG)
with Netlink(socket.NETLINK_ROUTE,
RTMGRP_IPV4_ROUTE | RTMGRP_IPV6_ROUTE | RTMGRP_NOTIFY) as netlink:
poll = select.poll()
poll.register(netlink.fileno(), select.POLLIN)
while poll.poll():
netlink.read()
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