iotop/genetlink.py

   1 '''
   2 Netlink message generation/parsing
   3
   4 Copyright 2007        Johannes Berg <johannes@sipsolutions.net>
   5
   6 GPLv2+; See copying for details.
   7 '''
   8
   9 import struct
  10 from netlink import *
  11
  12 CTRL_CMD_UNSPEC       = 0
  13 CTRL_CMD_NEWFAMILY    = 1
  14 CTRL_CMD_DELFAMILY    = 2
  15 CTRL_CMD_GETFAMILY    = 3
  16 CTRL_CMD_NEWOPS       = 4
  17 CTRL_CMD_DELOPS       = 5
  18 CTRL_CMD_GETOPS       = 6
  19
  20 CTRL_ATTR_UNSPEC      = 0
  21 CTRL_ATTR_FAMILY_ID   = 1
  22 CTRL_ATTR_FAMILY_NAME = 2
  23 CTRL_ATTR_VERSION     = 3
  24 CTRL_ATTR_HDRSIZE     = 4
  25 CTRL_ATTR_MAXATTR     = 5
  26 CTRL_ATTR_OPS         = 6
  27
  28 class GenlHdr:
  29     def __init__(self, cmd, version = 0):
  30         self.cmd = cmd
  31         self.version = version
  32     def _dump(self):
  33         return struct.pack("BBxx", self.cmd, self.version)
  34
  35 def _genl_hdr_parse(data):
  36     return GenlHdr(*struct.unpack("BBxx", data))
  37
  38 GENL_ID_CTRL        = NLMSG_MIN_TYPE
  39
  40 class GeNlMessage(Message):
  41     def __init__(self, family, cmd, attrs=[], flags=0):
  42         self.cmd = cmd
  43         self.attrs = attrs
  44         self.family = family
  45         Message.__init__(self, family, flags=flags,
  46                          payload=[GenlHdr(self.cmd)]+attrs)
  47
  48 class Controller:
  49     def __init__(self, conn):
  50         self.conn = conn
  51     def get_family_id(self, family):
  52         a = NulStrAttr(CTRL_ATTR_FAMILY_NAME, family)
  53         m = GeNlMessage(GENL_ID_CTRL, CTRL_CMD_GETFAMILY,
  54                         flags=NLM_F_REQUEST, attrs=[a])
  55         m.send(self.conn)
  56         m = self.conn.recv()
  57         gh = _genl_hdr_parse(m.payload[:4])
  58         attrs = parse_attributes(m.payload[4:])
  59         return attrs[CTRL_ATTR_FAMILY_ID].u16()
  60
  61 connection = Connection(NETLINK_GENERIC)
  62 controller = Controller(connection)