tools/net/ynl/lib/ynl.py

   1 # SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
   2
   3 from collections import namedtuple
   4 import functools
   5 import os
   6 import random
   7 import socket
   8 import struct
   9 from struct import Struct
  10 import yaml
  11 import ipaddress
  12 import uuid
  13
  14 from .nlspec import SpecFamily
  15
  16 #
  17 # Generic Netlink code which should really be in some library, but I can't quickly find one.
  18 #
  19
  20
  21 class Netlink:
  22     # Netlink socket
  23     SOL_NETLINK = 270
  24
  25     NETLINK_ADD_MEMBERSHIP = 1
  26     NETLINK_CAP_ACK = 10
  27     NETLINK_EXT_ACK = 11
  28
  29     # Netlink message
  30     NLMSG_ERROR = 2
  31     NLMSG_DONE = 3
  32
  33     NLM_F_REQUEST = 1
  34     NLM_F_ACK = 4
  35     NLM_F_ROOT = 0x100
  36     NLM_F_MATCH = 0x200
  37     NLM_F_APPEND = 0x800
  38
  39     NLM_F_CAPPED = 0x100
  40     NLM_F_ACK_TLVS = 0x200
  41
  42     NLM_F_DUMP = NLM_F_ROOT | NLM_F_MATCH
  43
  44     NLA_F_NESTED = 0x8000
  45     NLA_F_NET_BYTEORDER = 0x4000
  46
  47     NLA_TYPE_MASK = NLA_F_NESTED | NLA_F_NET_BYTEORDER
  48
  49     # Genetlink defines
  50     NETLINK_GENERIC = 16
  51
  52     GENL_ID_CTRL = 0x10
  53
  54     # nlctrl
  55     CTRL_CMD_GETFAMILY = 3
  56
  57     CTRL_ATTR_FAMILY_ID = 1
  58     CTRL_ATTR_FAMILY_NAME = 2
  59     CTRL_ATTR_MAXATTR = 5
  60     CTRL_ATTR_MCAST_GROUPS = 7
  61
  62     CTRL_ATTR_MCAST_GRP_NAME = 1
  63     CTRL_ATTR_MCAST_GRP_ID = 2
  64
  65     # Extack types
  66     NLMSGERR_ATTR_MSG = 1
  67     NLMSGERR_ATTR_OFFS = 2
  68     NLMSGERR_ATTR_COOKIE = 3
  69     NLMSGERR_ATTR_POLICY = 4
  70     NLMSGERR_ATTR_MISS_TYPE = 5
  71     NLMSGERR_ATTR_MISS_NEST = 6
  72
  73
  74 class NlError(Exception):
  75   def __init__(self, nl_msg):
  76     self.nl_msg = nl_msg
  77
  78   def __str__(self):
  79     return f"Netlink error: {os.strerror(-self.nl_msg.error)}\n{self.nl_msg}"
  80
  81
  82 class NlAttr:
  83     ScalarFormat = namedtuple('ScalarFormat', ['native', 'big', 'little'])
  84     type_formats = {
  85         'u8' : ScalarFormat(Struct('B'), Struct("B"),  Struct("B")),
  86         's8' : ScalarFormat(Struct('b'), Struct("b"),  Struct("b")),
  87         'u16': ScalarFormat(Struct('H'), Struct(">H"), Struct("<H")),
  88         's16': ScalarFormat(Struct('h'), Struct(">h"), Struct("<h")),
  89         'u32': ScalarFormat(Struct('I'), Struct(">I"), Struct("<I")),
  90         's32': ScalarFormat(Struct('i'), Struct(">i"), Struct("<i")),
  91         'u64': ScalarFormat(Struct('Q'), Struct(">Q"), Struct("<Q")),
  92         's64': ScalarFormat(Struct('q'), Struct(">q"), Struct("<q"))
  93     }
  94
  95     def __init__(self, raw, offset):
  96         self._len, self._type = struct.unpack("HH", raw[offset:offset + 4])
  97         self.type = self._type & ~Netlink.NLA_TYPE_MASK
  98         self.payload_len = self._len
  99         self.full_len = (self.payload_len + 3) & ~3
 100         self.raw = raw[offset + 4:offset + self.payload_len]
 101
 102     @classmethod
 103     def get_format(cls, attr_type, byte_order=None):
 104         format = cls.type_formats[attr_type]
 105         if byte_order:
 106             return format.big if byte_order == "big-endian" \
 107                 else format.little
 108         return format.native
 109
 110     @classmethod
 111     def formatted_string(cls, raw, display_hint):
 112         if display_hint == 'mac':
 113             formatted = ':'.join('%02x' % b for b in raw)
 114         elif display_hint == 'hex':
 115             formatted = bytes.hex(raw, ' ')
 116         elif display_hint in [ 'ipv4', 'ipv6' ]:
 117             formatted = format(ipaddress.ip_address(raw))
 118         elif display_hint == 'uuid':
 119             formatted = str(uuid.UUID(bytes=raw))
 120         else:
 121             formatted = raw
 122         return formatted
 123
 124     def as_scalar(self, attr_type, byte_order=None):
 125         format = self.get_format(attr_type, byte_order)
 126         return format.unpack(self.raw)[0]
 127
 128     def as_strz(self):
 129         return self.raw.decode('ascii')[:-1]
 130
 131     def as_bin(self):
 132         return self.raw
 133
 134     def as_c_array(self, type):
 135         format = self.get_format(type)
 136         return [ x[0] for x in format.iter_unpack(self.raw) ]
 137
 138     def as_struct(self, members):
 139         value = dict()
 140         offset = 0
 141         for m in members:
 142             # TODO: handle non-scalar members
 143             if m.type == 'binary':
 144                 decoded = self.raw[offset:offset+m['len']]
 145                 offset += m['len']
 146             elif m.type in NlAttr.type_formats:
 147                 format = self.get_format(m.type, m.byte_order)
 148                 [ decoded ] = format.unpack_from(self.raw, offset)
 149                 offset += format.size
 150             if m.display_hint:
 151                 decoded = self.formatted_string(decoded, m.display_hint)
 152             value[m.name] = decoded
 153         return value
 154
 155     def __repr__(self):
 156         return f"[type:{self.type} len:{self._len}] {self.raw}"
 157
 158
 159 class NlAttrs:
 160     def __init__(self, msg):
 161         self.attrs = []
 162
 163         offset = 0
 164         while offset < len(msg):
 165             attr = NlAttr(msg, offset)
 166             offset += attr.full_len
 167             self.attrs.append(attr)
 168
 169     def __iter__(self):
 170         yield from self.attrs
 171
 172     def __repr__(self):
 173         msg = ''
 174         for a in self.attrs:
 175             if msg:
 176                 msg += '\n'
 177             msg += repr(a)
 178         return msg
 179
 180
 181 class NlMsg:
 182     def __init__(self, msg, offset, attr_space=None):
 183         self.hdr = msg[offset:offset + 16]
 184
 185         self.nl_len, self.nl_type, self.nl_flags, self.nl_seq, self.nl_portid = \
 186             struct.unpack("IHHII", self.hdr)
 187
 188         self.raw = msg[offset + 16:offset + self.nl_len]
 189
 190         self.error = 0
 191         self.done = 0
 192
 193         extack_off = None
 194         if self.nl_type == Netlink.NLMSG_ERROR:
 195             self.error = struct.unpack("i", self.raw[0:4])[0]
 196             self.done = 1
 197             extack_off = 20
 198         elif self.nl_type == Netlink.NLMSG_DONE:
 199             self.done = 1
 200             extack_off = 4
 201
 202         self.extack = None
 203         if self.nl_flags & Netlink.NLM_F_ACK_TLVS and extack_off:
 204             self.extack = dict()
 205             extack_attrs = NlAttrs(self.raw[extack_off:])
 206             for extack in extack_attrs:
 207                 if extack.type == Netlink.NLMSGERR_ATTR_MSG:
 208                     self.extack['msg'] = extack.as_strz()
 209                 elif extack.type == Netlink.NLMSGERR_ATTR_MISS_TYPE:
 210                     self.extack['miss-type'] = extack.as_scalar('u32')
 211                 elif extack.type == Netlink.NLMSGERR_ATTR_MISS_NEST:
 212                     self.extack['miss-nest'] = extack.as_scalar('u32')
 213                 elif extack.type == Netlink.NLMSGERR_ATTR_OFFS:
 214                     self.extack['bad-attr-offs'] = extack.as_scalar('u32')
 215                 else:
 216                     if 'unknown' not in self.extack:
 217                         self.extack['unknown'] = []
 218                     self.extack['unknown'].append(extack)
 219
 220             if attr_space:
 221                 # We don't have the ability to parse nests yet, so only do global
 222                 if 'miss-type' in self.extack and 'miss-nest' not in self.extack:
 223                     miss_type = self.extack['miss-type']
 224                     if miss_type in attr_space.attrs_by_val:
 225                         spec = attr_space.attrs_by_val[miss_type]
 226                         desc = spec['name']
 227                         if 'doc' in spec:
 228                             desc += f" ({spec['doc']})"
 229                         self.extack['miss-type'] = desc
 230
 231     def __repr__(self):
 232         msg = f"nl_len = {self.nl_len} ({len(self.raw)}) nl_flags = 0x{self.nl_flags:x} nl_type = {self.nl_type}\n"
 233         if self.error:
 234             msg += '\terror: ' + str(self.error)
 235         if self.extack:
 236             msg += '\textack: ' + repr(self.extack)
 237         return msg
 238
 239
 240 class NlMsgs:
 241     def __init__(self, data, attr_space=None):
 242         self.msgs = []
 243
 244         offset = 0
 245         while offset < len(data):
 246             msg = NlMsg(data, offset, attr_space=attr_space)
 247             offset += msg.nl_len
 248             self.msgs.append(msg)
 249
 250     def __iter__(self):
 251         yield from self.msgs
 252
 253
 254 genl_family_name_to_id = None
 255
 256
 257 def _genl_msg(nl_type, nl_flags, genl_cmd, genl_version, seq=None):
 258     # we prepend length in _genl_msg_finalize()
 259     if seq is None:
 260         seq = random.randint(1, 1024)
 261     nlmsg = struct.pack("HHII", nl_type, nl_flags, seq, 0)
 262     genlmsg = struct.pack("BBH", genl_cmd, genl_version, 0)
 263     return nlmsg + genlmsg
 264
 265
 266 def _genl_msg_finalize(msg):
 267     return struct.pack("I", len(msg) + 4) + msg
 268
 269
 270 def _genl_load_families():
 271     with socket.socket(socket.AF_NETLINK, socket.SOCK_RAW, Netlink.NETLINK_GENERIC) as sock:
 272         sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_CAP_ACK, 1)
 273
 274         msg = _genl_msg(Netlink.GENL_ID_CTRL,
 275                         Netlink.NLM_F_REQUEST | Netlink.NLM_F_ACK | Netlink.NLM_F_DUMP,
 276                         Netlink.CTRL_CMD_GETFAMILY, 1)
 277         msg = _genl_msg_finalize(msg)
 278
 279         sock.send(msg, 0)
 280
 281         global genl_family_name_to_id
 282         genl_family_name_to_id = dict()
 283
 284         while True:
 285             reply = sock.recv(128 * 1024)
 286             nms = NlMsgs(reply)
 287             for nl_msg in nms:
 288                 if nl_msg.error:
 289                     print("Netlink error:", nl_msg.error)
 290                     return
 291                 if nl_msg.done:
 292                     return
 293
 294                 gm = GenlMsg(nl_msg)
 295                 fam = dict()
 296                 for attr in gm.raw_attrs:
 297                     if attr.type == Netlink.CTRL_ATTR_FAMILY_ID:
 298                         fam['id'] = attr.as_scalar('u16')
 299                     elif attr.type == Netlink.CTRL_ATTR_FAMILY_NAME:
 300                         fam['name'] = attr.as_strz()
 301                     elif attr.type == Netlink.CTRL_ATTR_MAXATTR:
 302                         fam['maxattr'] = attr.as_scalar('u32')
 303                     elif attr.type == Netlink.CTRL_ATTR_MCAST_GROUPS:
 304                         fam['mcast'] = dict()
 305                         for entry in NlAttrs(attr.raw):
 306                             mcast_name = None
 307                             mcast_id = None
 308                             for entry_attr in NlAttrs(entry.raw):
 309                                 if entry_attr.type == Netlink.CTRL_ATTR_MCAST_GRP_NAME:
 310                                     mcast_name = entry_attr.as_strz()
 311                                 elif entry_attr.type == Netlink.CTRL_ATTR_MCAST_GRP_ID:
 312                                     mcast_id = entry_attr.as_scalar('u32')
 313                             if mcast_name and mcast_id is not None:
 314                                 fam['mcast'][mcast_name] = mcast_id
 315                 if 'name' in fam and 'id' in fam:
 316                     genl_family_name_to_id[fam['name']] = fam
 317
 318
 319 class GenlMsg:
 320     def __init__(self, nl_msg, fixed_header_members=[]):
 321         self.nl = nl_msg
 322
 323         self.hdr = nl_msg.raw[0:4]
 324         offset = 4
 325
 326         self.genl_cmd, self.genl_version, _ = struct.unpack("BBH", self.hdr)
 327
 328         self.fixed_header_attrs = dict()
 329         for m in fixed_header_members:
 330             format = NlAttr.get_format(m.type, m.byte_order)
 331             decoded = format.unpack_from(nl_msg.raw, offset)
 332             offset += format.size
 333             self.fixed_header_attrs[m.name] = decoded[0]
 334
 335         self.raw = nl_msg.raw[offset:]
 336         self.raw_attrs = NlAttrs(self.raw)
 337
 338     def __repr__(self):
 339         msg = repr(self.nl)
 340         msg += f"\tgenl_cmd = {self.genl_cmd} genl_ver = {self.genl_version}\n"
 341         for a in self.raw_attrs:
 342             msg += '\t\t' + repr(a) + '\n'
 343         return msg
 344
 345
 346 class GenlFamily:
 347     def __init__(self, family_name):
 348         self.family_name = family_name
 349
 350         global genl_family_name_to_id
 351         if genl_family_name_to_id is None:
 352             _genl_load_families()
 353
 354         self.genl_family = genl_family_name_to_id[family_name]
 355         self.family_id = genl_family_name_to_id[family_name]['id']
 356
 357
 358 #
 359 # YNL implementation details.
 360 #
 361
 362
 363 class YnlFamily(SpecFamily):
 364     def __init__(self, def_path, schema=None):
 365         super().__init__(def_path, schema)
 366
 367         self.include_raw = False
 368
 369         self.sock = socket.socket(socket.AF_NETLINK, socket.SOCK_RAW, Netlink.NETLINK_GENERIC)
 370         self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_CAP_ACK, 1)
 371         self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_EXT_ACK, 1)
 372
 373         self.async_msg_ids = set()
 374         self.async_msg_queue = []
 375
 376         for msg in self.msgs.values():
 377             if msg.is_async:
 378                 self.async_msg_ids.add(msg.rsp_value)
 379
 380         for op_name, op in self.ops.items():
 381             bound_f = functools.partial(self._op, op_name)
 382             setattr(self, op.ident_name, bound_f)
 383
 384         try:
 385             self.family = GenlFamily(self.yaml['name'])
 386         except KeyError:
 387             raise Exception(f"Family '{self.yaml['name']}' not supported by the kernel")
 388
 389     def ntf_subscribe(self, mcast_name):
 390         if mcast_name not in self.family.genl_family['mcast']:
 391             raise Exception(f'Multicast group "{mcast_name}" not present in the family')
 392
 393         self.sock.bind((0, 0))
 394         self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_ADD_MEMBERSHIP,
 395                              self.family.genl_family['mcast'][mcast_name])
 396
 397     def _add_attr(self, space, name, value):
 398         attr = self.attr_sets[space][name]
 399         nl_type = attr.value
 400         if attr["type"] == 'nest':
 401             nl_type |= Netlink.NLA_F_NESTED
 402             attr_payload = b''
 403             for subname, subvalue in value.items():
 404                 attr_payload += self._add_attr(attr['nested-attributes'], subname, subvalue)
 405         elif attr["type"] == 'flag':
 406             attr_payload = b''
 407         elif attr["type"] == 'string':
 408             attr_payload = str(value).encode('ascii') + b'\x00'
 409         elif attr["type"] == 'binary':
 410             attr_payload = bytes.fromhex(value)
 411         elif attr['type'] in NlAttr.type_formats:
 412             format = NlAttr.get_format(attr['type'], attr.byte_order)
 413             attr_payload = format.pack(int(value))
 414         else:
 415             raise Exception(f'Unknown type at {space} {name} {value} {attr["type"]}')
 416
 417         pad = b'\x00' * ((4 - len(attr_payload) % 4) % 4)
 418         return struct.pack('HH', len(attr_payload) + 4, nl_type) + attr_payload + pad
 419
 420     def _decode_enum(self, rsp, attr_spec):
 421         raw = rsp[attr_spec['name']]
 422         enum = self.consts[attr_spec['enum']]
 423         i = attr_spec.get('value-start', 0)
 424         if 'enum-as-flags' in attr_spec and attr_spec['enum-as-flags']:
 425             value = set()
 426             while raw:
 427                 if raw & 1:
 428                     value.add(enum.entries_by_val[i].name)
 429                 raw >>= 1
 430                 i += 1
 431         else:
 432             value = enum.entries_by_val[raw - i].name
 433         rsp[attr_spec['name']] = value
 434
 435     def _decode_binary(self, attr, attr_spec):
 436         if attr_spec.struct_name:
 437             members = self.consts[attr_spec.struct_name]
 438             decoded = attr.as_struct(members)
 439             for m in members:
 440                 if m.enum:
 441                     self._decode_enum(decoded, m)
 442         elif attr_spec.sub_type:
 443             decoded = attr.as_c_array(attr_spec.sub_type)
 444         else:
 445             decoded = attr.as_bin()
 446             if attr_spec.display_hint:
 447                 decoded = NlAttr.formatted_string(decoded, attr_spec.display_hint)
 448         return decoded
 449
 450     def _decode(self, attrs, space):
 451         attr_space = self.attr_sets[space]
 452         rsp = dict()
 453         for attr in attrs:
 454             attr_spec = attr_space.attrs_by_val[attr.type]
 455             if attr_spec["type"] == 'nest':
 456                 subdict = self._decode(NlAttrs(attr.raw), attr_spec['nested-attributes'])
 457                 decoded = subdict
 458             elif attr_spec["type"] == 'string':
 459                 decoded = attr.as_strz()
 460             elif attr_spec["type"] == 'binary':
 461                 decoded = self._decode_binary(attr, attr_spec)
 462             elif attr_spec["type"] == 'flag':
 463                 decoded = True
 464             elif attr_spec["type"] in NlAttr.type_formats:
 465                 decoded = attr.as_scalar(attr_spec['type'], attr_spec.byte_order)
 466             else:
 467                 raise Exception(f'Unknown {attr_spec["type"]} with name {attr_spec["name"]}')
 468
 469             if not attr_spec.is_multi:
 470                 rsp[attr_spec['name']] = decoded
 471             elif attr_spec.name in rsp:
 472                 rsp[attr_spec.name].append(decoded)
 473             else:
 474                 rsp[attr_spec.name] = [decoded]
 475
 476             if 'enum' in attr_spec:
 477                 self._decode_enum(rsp, attr_spec)
 478         return rsp
 479
 480     def _decode_extack_path(self, attrs, attr_set, offset, target):
 481         for attr in attrs:
 482             attr_spec = attr_set.attrs_by_val[attr.type]
 483             if offset > target:
 484                 break
 485             if offset == target:
 486                 return '.' + attr_spec.name
 487
 488             if offset + attr.full_len <= target:
 489                 offset += attr.full_len
 490                 continue
 491             if attr_spec['type'] != 'nest':
 492                 raise Exception(f"Can't dive into {attr.type} ({attr_spec['name']}) for extack")
 493             offset += 4
 494             subpath = self._decode_extack_path(NlAttrs(attr.raw),
 495                                                self.attr_sets[attr_spec['nested-attributes']],
 496                                                offset, target)
 497             if subpath is None:
 498                 return None
 499             return '.' + attr_spec.name + subpath
 500
 501         return None
 502
 503     def _decode_extack(self, request, attr_space, extack):
 504         if 'bad-attr-offs' not in extack:
 505             return
 506
 507         genl_req = GenlMsg(NlMsg(request, 0, attr_space=attr_space))
 508         path = self._decode_extack_path(genl_req.raw_attrs, attr_space,
 509                                         20, extack['bad-attr-offs'])
 510         if path:
 511             del extack['bad-attr-offs']
 512             extack['bad-attr'] = path
 513
 514     def handle_ntf(self, nl_msg, genl_msg):
 515         msg = dict()
 516         if self.include_raw:
 517             msg['nlmsg'] = nl_msg
 518             msg['genlmsg'] = genl_msg
 519         op = self.rsp_by_value[genl_msg.genl_cmd]
 520         msg['name'] = op['name']
 521         msg['msg'] = self._decode(genl_msg.raw_attrs, op.attr_set.name)
 522         self.async_msg_queue.append(msg)
 523
 524     def check_ntf(self):
 525         while True:
 526             try:
 527                 reply = self.sock.recv(128 * 1024, socket.MSG_DONTWAIT)
 528             except BlockingIOError:
 529                 return
 530
 531             nms = NlMsgs(reply)
 532             for nl_msg in nms:
 533                 if nl_msg.error:
 534                     print("Netlink error in ntf!?", os.strerror(-nl_msg.error))
 535                     print(nl_msg)
 536                     continue
 537                 if nl_msg.done:
 538                     print("Netlink done while checking for ntf!?")
 539                     continue
 540
 541                 gm = GenlMsg(nl_msg)
 542                 if gm.genl_cmd not in self.async_msg_ids:
 543                     print("Unexpected msg id done while checking for ntf", gm)
 544                     continue
 545
 546                 self.handle_ntf(nl_msg, gm)
 547
 548     def operation_do_attributes(self, name):
 549       """
 550       For a given operation name, find and return a supported
 551       set of attributes (as a dict).
 552       """
 553       op = self.find_operation(name)
 554       if not op:
 555         return None
 556
 557       return op['do']['request']['attributes'].copy()
 558
 559     def _op(self, method, vals, dump=False):
 560         op = self.ops[method]
 561
 562         nl_flags = Netlink.NLM_F_REQUEST | Netlink.NLM_F_ACK
 563         if dump:
 564             nl_flags |= Netlink.NLM_F_DUMP
 565
 566         req_seq = random.randint(1024, 65535)
 567         msg = _genl_msg(self.family.family_id, nl_flags, op.req_value, 1, req_seq)
 568         fixed_header_members = []
 569         if op.fixed_header:
 570             fixed_header_members = self.consts[op.fixed_header].members
 571             for m in fixed_header_members:
 572                 value = vals.pop(m.name) if m.name in vals else 0
 573                 format = NlAttr.get_format(m.type, m.byte_order)
 574                 msg += format.pack(value)
 575         for name, value in vals.items():
 576             msg += self._add_attr(op.attr_set.name, name, value)
 577         msg = _genl_msg_finalize(msg)
 578
 579         self.sock.send(msg, 0)
 580
 581         done = False
 582         rsp = []
 583         while not done:
 584             reply = self.sock.recv(128 * 1024)
 585             nms = NlMsgs(reply, attr_space=op.attr_set)
 586             for nl_msg in nms:
 587                 if nl_msg.extack:
 588                     self._decode_extack(msg, op.attr_set, nl_msg.extack)
 589
 590                 if nl_msg.error:
 591                     raise NlError(nl_msg)
 592                 if nl_msg.done:
 593                     if nl_msg.extack:
 594                         print("Netlink warning:")
 595                         print(nl_msg)
 596                     done = True
 597                     break
 598
 599                 gm = GenlMsg(nl_msg, fixed_header_members)
 600                 # Check if this is a reply to our request
 601                 if nl_msg.nl_seq != req_seq or gm.genl_cmd != op.rsp_value:
 602                     if gm.genl_cmd in self.async_msg_ids:
 603                         self.handle_ntf(nl_msg, gm)
 604                         continue
 605                     else:
 606                         print('Unexpected message: ' + repr(gm))
 607                         continue
 608
 609                 rsp_msg = self._decode(gm.raw_attrs, op.attr_set.name)
 610                 rsp_msg.update(gm.fixed_header_attrs)
 611                 rsp.append(rsp_msg)
 612
 613         if not rsp:
 614             return None
 615         if not dump and len(rsp) == 1:
 616             return rsp[0]
 617         return rsp
 618
 619     def do(self, method, vals):
 620         return self._op(method, vals)
 621
 622     def dump(self, method, vals):
 623         return self._op(method, vals, dump=True)