hostap/tests/hwsim/netlink.py

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#
# (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 + '\0' * 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 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):
contents = []
for attr in payload:
contents.append(attr._dump())
self.payload = ''.join(contents)
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))