237 lines
6.8 KiB
Python
237 lines
6.8 KiB
Python
#
|
|
# (Generic) Netlink message generation/parsing
|
|
# Copyright (c) 2007 Johannes Berg <johannes@sipsolutions.net>
|
|
# Copyright (c) 2014 Intel Corporation
|
|
#
|
|
# This software may be distributed under the terms of the BSD license.
|
|
# See README for more details.
|
|
|
|
import struct, socket
|
|
|
|
# flags
|
|
NLM_F_REQUEST = 1
|
|
NLM_F_MULTI = 2
|
|
NLM_F_ACK = 4
|
|
NLM_F_ECHO = 8
|
|
|
|
# types
|
|
NLMSG_NOOP = 1
|
|
NLMSG_ERROR = 2
|
|
NLMSG_DONE = 3
|
|
NLMSG_OVERRUN = 4
|
|
NLMSG_MIN_TYPE = 0x10
|
|
|
|
class Attr(object):
|
|
def __init__(self, attr_type, data, *values):
|
|
self._type = attr_type
|
|
if len(values):
|
|
self._data = struct.pack(data, *values)
|
|
else:
|
|
self._data = data
|
|
|
|
def _dump(self):
|
|
hdr = struct.pack("HH", len(self._data) + 4, self._type)
|
|
length = len(self._data)
|
|
pad = ((length + 4 - 1) & ~3) - length
|
|
return hdr + self._data + b'\x00' * pad
|
|
|
|
def __repr__(self):
|
|
return '<Attr type %d, data "%s">' % (self._type, repr(self._data))
|
|
|
|
def u16(self):
|
|
return struct.unpack('H', self._data)[0]
|
|
def s16(self):
|
|
return struct.unpack('h', self._data)[0]
|
|
def u32(self):
|
|
return struct.unpack('I', self._data)[0]
|
|
def s32(self):
|
|
return struct.unpack('i', self._data)[0]
|
|
def str(self):
|
|
return self._data
|
|
def nulstr(self):
|
|
return self._data.split('\0')[0]
|
|
def nested(self):
|
|
return parse_attributes(self._data)
|
|
|
|
class StrAttr(Attr):
|
|
def __init__(self, attr_type, data):
|
|
Attr.__init__(self, attr_type, "%ds" % len(data), data)
|
|
|
|
class NulStrAttr(Attr):
|
|
def __init__(self, attr_type, data):
|
|
Attr.__init__(self, attr_type, "%dsB" % len(data), data, 0)
|
|
|
|
class U32Attr(Attr):
|
|
def __init__(self, attr_type, val):
|
|
Attr.__init__(self, attr_type, "I", val)
|
|
|
|
class U8Attr(Attr):
|
|
def __init__(self, attr_type, val):
|
|
Attr.__init__(self, attr_type, "B", val)
|
|
|
|
class FlagAttr(Attr):
|
|
def __init__(self, attr_type):
|
|
Attr.__init__(self, attr_type, b"")
|
|
|
|
class Nested(Attr):
|
|
def __init__(self, attr_type, attrs):
|
|
self.attrs = attrs
|
|
self.type = attr_type
|
|
|
|
def _dump(self):
|
|
contents = []
|
|
for attr in self.attrs:
|
|
contents.append(attr._dump())
|
|
contents = ''.join(contents)
|
|
length = len(contents)
|
|
hdr = struct.pack("HH", length+4, self.type)
|
|
return hdr + contents
|
|
|
|
NETLINK_ROUTE = 0
|
|
NETLINK_UNUSED = 1
|
|
NETLINK_USERSOCK = 2
|
|
NETLINK_FIREWALL = 3
|
|
NETLINK_INET_DIAG = 4
|
|
NETLINK_NFLOG = 5
|
|
NETLINK_XFRM = 6
|
|
NETLINK_SELINUX = 7
|
|
NETLINK_ISCSI = 8
|
|
NETLINK_AUDIT = 9
|
|
NETLINK_FIB_LOOKUP = 10
|
|
NETLINK_CONNECTOR = 11
|
|
NETLINK_NETFILTER = 12
|
|
NETLINK_IP6_FW = 13
|
|
NETLINK_DNRTMSG = 14
|
|
NETLINK_KOBJECT_UEVENT = 15
|
|
NETLINK_GENERIC = 16
|
|
|
|
class Message(object):
|
|
def __init__(self, msg_type, flags=0, seq=-1, payload=None):
|
|
self.type = msg_type
|
|
self.flags = flags
|
|
self.seq = seq
|
|
self.pid = -1
|
|
payload = payload or []
|
|
if isinstance(payload, list):
|
|
self.payload = bytes()
|
|
for attr in payload:
|
|
self.payload += attr._dump()
|
|
else:
|
|
self.payload = payload
|
|
|
|
def send(self, conn):
|
|
if self.seq == -1:
|
|
self.seq = conn.seq()
|
|
|
|
self.pid = conn.pid
|
|
length = len(self.payload)
|
|
|
|
hdr = struct.pack("IHHII", length + 4*4, self.type,
|
|
self.flags, self.seq, self.pid)
|
|
conn.send(hdr + self.payload)
|
|
|
|
def __repr__(self):
|
|
return '<netlink.Message type=%d, pid=%d, seq=%d, flags=0x%x "%s">' % (
|
|
self.type, self.pid, self.seq, self.flags, repr(self.payload))
|
|
|
|
@property
|
|
def ret(self):
|
|
assert self.type == NLMSG_ERROR
|
|
return struct.unpack("i", self.payload[:4])[0]
|
|
|
|
def send_and_recv(self, conn):
|
|
self.send(conn)
|
|
while True:
|
|
m = conn.recv()
|
|
if m.seq == self.seq:
|
|
return m
|
|
|
|
class Connection(object):
|
|
def __init__(self, nltype, groups=0, unexpected_msg_handler=None):
|
|
self.descriptor = socket.socket(socket.AF_NETLINK,
|
|
socket.SOCK_RAW, nltype)
|
|
self.descriptor.setsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF, 65536)
|
|
self.descriptor.setsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF, 65536)
|
|
self.descriptor.bind((0, groups))
|
|
self.pid, self.groups = self.descriptor.getsockname()
|
|
self._seq = 0
|
|
self.unexpected = unexpected_msg_handler
|
|
def send(self, msg):
|
|
self.descriptor.send(msg)
|
|
def recv(self):
|
|
contents = self.descriptor.recv(16384)
|
|
# XXX: python doesn't give us message flags, check
|
|
# len(contents) vs. msglen for TRUNC
|
|
msglen, msg_type, flags, seq, pid = struct.unpack("IHHII",
|
|
contents[:16])
|
|
msg = Message(msg_type, flags, seq, contents[16:])
|
|
msg.pid = pid
|
|
if msg.type == NLMSG_ERROR:
|
|
import os
|
|
errno = msg.ret
|
|
if errno < 0:
|
|
err = OSError("Netlink error: %s (%d)" % (
|
|
os.strerror(-errno), -errno))
|
|
err.errno = -errno
|
|
raise err
|
|
return msg
|
|
def seq(self):
|
|
self._seq += 1
|
|
return self._seq
|
|
|
|
def parse_attributes(data):
|
|
attrs = {}
|
|
while len(data):
|
|
attr_len, attr_type = struct.unpack("HH", data[:4])
|
|
attrs[attr_type] = Attr(attr_type, data[4:attr_len])
|
|
attr_len = ((attr_len + 4 - 1) & ~3)
|
|
data = data[attr_len:]
|
|
return attrs
|
|
|
|
|
|
|
|
CTRL_CMD_UNSPEC = 0
|
|
CTRL_CMD_NEWFAMILY = 1
|
|
CTRL_CMD_DELFAMILY = 2
|
|
CTRL_CMD_GETFAMILY = 3
|
|
CTRL_CMD_NEWOPS = 4
|
|
CTRL_CMD_DELOPS = 5
|
|
CTRL_CMD_GETOPS = 6
|
|
|
|
CTRL_ATTR_UNSPEC = 0
|
|
CTRL_ATTR_FAMILY_ID = 1
|
|
CTRL_ATTR_FAMILY_NAME = 2
|
|
CTRL_ATTR_VERSION = 3
|
|
CTRL_ATTR_HDRSIZE = 4
|
|
CTRL_ATTR_MAXATTR = 5
|
|
CTRL_ATTR_OPS = 6
|
|
|
|
class GenlHdr(object):
|
|
def __init__(self, cmd, version=0):
|
|
self.cmd = cmd
|
|
self.version = version
|
|
def _dump(self):
|
|
return struct.pack("BBxx", self.cmd, self.version)
|
|
|
|
def _genl_hdr_parse(data):
|
|
return GenlHdr(*struct.unpack("BBxx", data))
|
|
|
|
GENL_ID_CTRL = NLMSG_MIN_TYPE
|
|
|
|
class GenlMessage(Message):
|
|
def __init__(self, family, cmd, attrs=[], flags=0):
|
|
Message.__init__(self, family, flags=flags, payload=[GenlHdr(cmd)] + attrs)
|
|
|
|
class GenlController(object):
|
|
def __init__(self, conn):
|
|
self.conn = conn
|
|
def get_family_id(self, family):
|
|
a = NulStrAttr(CTRL_ATTR_FAMILY_NAME, family)
|
|
m = GenlMessage(GENL_ID_CTRL, CTRL_CMD_GETFAMILY, flags=NLM_F_REQUEST, attrs=[a])
|
|
m.send(self.conn)
|
|
m = self.conn.recv()
|
|
gh = _genl_hdr_parse(m.payload[:4])
|
|
attrs = parse_attributes(m.payload[4:])
|
|
return attrs[CTRL_ATTR_FAMILY_ID].u16()
|
|
|
|
genl_controller = GenlController(Connection(NETLINK_GENERIC))
|