Mini Shell
'''
Netlink proxy engine
'''
import errno
import logging
import struct
import threading
import traceback
from pyroute2.netlink.exceptions import NetlinkError
log = logging.getLogger(__name__)
class NetlinkProxy(object):
'''
Proxy schemes::
User -> NetlinkProxy -> Kernel
|
<---------+
User <- NetlinkProxy <- Kernel
'''
def __init__(self, policy='forward', nl=None, lock=None):
self.nl = nl
self.lock = lock or threading.Lock()
self.pmap = {}
self.policy = policy
def handle(self, msg):
#
# match the packet
#
ptype = msg['header']['type']
plugin = self.pmap.get(ptype, None)
if plugin is not None:
with self.lock:
try:
ret = plugin(msg, self.nl)
if ret is None:
#
# The packet is terminated in the plugin,
# return the NLMSG_ERR == 0
#
# FIXME: optimize
#
newmsg = struct.pack('IHH', 40, 2, 0)
newmsg += msg.data[8:16]
newmsg += struct.pack('I', 0)
# nlmsgerr struct alignment
newmsg += b'\0' * 20
return {'verdict': self.policy, 'data': newmsg}
else:
return ret
except Exception as e:
log.error(''.join(traceback.format_stack()))
log.error(traceback.format_exc())
# errmsg
if isinstance(e, (OSError, IOError)):
code = e.errno
elif isinstance(e, NetlinkError):
code = e.code
else:
code = errno.ECOMM
newmsg = struct.pack('HH', 2, 0)
newmsg += msg.data[8:16]
newmsg += struct.pack('I', code)
newmsg += msg.data
newmsg = struct.pack('I', len(newmsg) + 4) + newmsg
return {'verdict': 'error', 'data': newmsg}
return None
Zerion Mini Shell 1.0