2 # (Generic) Netlink message generation/parsing
3 # Copyright (c) 2007 Johannes Berg <johannes@sipsolutions.net>
4 # Copyright (c) 2014 Intel Corporation
6 # This software may be distributed under the terms of the BSD license.
7 # See README for more details.
25 def __init__(self, attr_type, data, *values):
26 self._type = attr_type
28 self._data = struct.pack(data, *values)
33 hdr = struct.pack("HH", len(self._data) + 4, self._type)
34 length = len(self._data)
35 pad = ((length + 4 - 1) & ~3 ) - length
36 return hdr + self._data + '\0' * pad
39 return '<Attr type %d, data "%s">' % (self._type, repr(self._data))
42 return struct.unpack('H', self._data)[0]
44 return struct.unpack('h', self._data)[0]
46 return struct.unpack('I', self._data)[0]
48 return struct.unpack('i', self._data)[0]
52 return self._data.split('\0')[0]
54 return parse_attributes(self._data)
57 def __init__(self, attr_type, data):
58 Attr.__init__(self, attr_type, "%ds" % len(data), data)
60 class NulStrAttr(Attr):
61 def __init__(self, attr_type, data):
62 Attr.__init__(self, attr_type, "%dsB" % len(data), data, 0)
65 def __init__(self, attr_type, val):
66 Attr.__init__(self, attr_type, "I", val)
69 def __init__(self, attr_type, val):
70 Attr.__init__(self, attr_type, "B", val)
73 def __init__(self, attr_type):
74 Attr.__init__(self, attr_type, "")
77 def __init__(self, attr_type, attrs):
83 for attr in self.attrs:
84 contents.append(attr._dump())
85 contents = ''.join(contents)
86 length = len(contents)
87 hdr = struct.pack("HH", length+4, self.type)
100 NETLINK_FIB_LOOKUP = 10
101 NETLINK_CONNECTOR = 11
102 NETLINK_NETFILTER = 12
105 NETLINK_KOBJECT_UEVENT = 15
108 class Message(object):
109 def __init__(self, msg_type, flags=0, seq=-1, payload=None):
114 payload = payload or []
115 if isinstance(payload, list):
118 contents.append(attr._dump())
119 self.payload = ''.join(contents)
121 self.payload = payload
123 def send(self, conn):
125 self.seq = conn.seq()
128 length = len(self.payload)
130 hdr = struct.pack("IHHII", length + 4*4, self.type,
131 self.flags, self.seq, self.pid)
132 conn.send(hdr + self.payload)
135 return '<netlink.Message type=%d, pid=%d, seq=%d, flags=0x%x "%s">' % (
136 self.type, self.pid, self.seq, self.flags, repr(self.payload))
140 assert self.type == NLMSG_ERROR
141 return struct.unpack("i", self.payload[:4])[0]
143 def send_and_recv(self, conn):
147 if m.seq == self.seq:
150 class Connection(object):
151 def __init__(self, nltype, groups=0, unexpected_msg_handler=None):
152 self.descriptor = socket.socket(socket.AF_NETLINK,
153 socket.SOCK_RAW, nltype)
154 self.descriptor.setsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF, 65536)
155 self.descriptor.setsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF, 65536)
156 self.descriptor.bind((0, groups))
157 self.pid, self.groups = self.descriptor.getsockname()
159 self.unexpected = unexpected_msg_handler
161 self.descriptor.send(msg)
163 contents = self.descriptor.recv(16384)
164 # XXX: python doesn't give us message flags, check
165 # len(contents) vs. msglen for TRUNC
166 msglen, msg_type, flags, seq, pid = struct.unpack("IHHII",
168 msg = Message(msg_type, flags, seq, contents[16:])
170 if msg.type == NLMSG_ERROR:
174 err = OSError("Netlink error: %s (%d)" % (
175 os.strerror(-errno), -errno))
183 def parse_attributes(data):
186 attr_len, attr_type = struct.unpack("HH", data[:4])
187 attrs[attr_type] = Attr(attr_type, data[4:attr_len])
188 attr_len = ((attr_len + 4 - 1) & ~3 )
189 data = data[attr_len:]
195 CTRL_CMD_NEWFAMILY = 1
196 CTRL_CMD_DELFAMILY = 2
197 CTRL_CMD_GETFAMILY = 3
203 CTRL_ATTR_FAMILY_ID = 1
204 CTRL_ATTR_FAMILY_NAME = 2
205 CTRL_ATTR_VERSION = 3
206 CTRL_ATTR_HDRSIZE = 4
207 CTRL_ATTR_MAXATTR = 5
210 class GenlHdr(object):
211 def __init__(self, cmd, version = 0):
213 self.version = version
215 return struct.pack("BBxx", self.cmd, self.version)
217 def _genl_hdr_parse(data):
218 return GenlHdr(*struct.unpack("BBxx", data))
220 GENL_ID_CTRL = NLMSG_MIN_TYPE
222 class GenlMessage(Message):
223 def __init__(self, family, cmd, attrs=[], flags=0):
224 Message.__init__(self, family, flags=flags, payload=[GenlHdr(cmd)] + attrs)
226 class GenlController(object):
227 def __init__(self, conn):
229 def get_family_id(self, family):
230 a = NulStrAttr(CTRL_ATTR_FAMILY_NAME, family)
231 m = GenlMessage(GENL_ID_CTRL, CTRL_CMD_GETFAMILY, flags=NLM_F_REQUEST, attrs=[a])
234 gh = _genl_hdr_parse(m.payload[:4])
235 attrs = parse_attributes(m.payload[4:])
236 return attrs[CTRL_ATTR_FAMILY_ID].u16()
238 genl_controller = GenlController(Connection(NETLINK_GENERIC))