# SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
from collections import namedtuple
from enum import Enum
import functools
import os
import random
import socket
import struct
from struct import Struct
import sys
import yaml
import ipaddress
import uuid
from .nlspec import SpecFamily
#
# Generic Netlink code which should really be in some library, but I can't quickly find one.
#
class Netlink:
# Netlink socket
SOL_NETLINK = 270
NETLINK_ADD_MEMBERSHIP = 1
NETLINK_CAP_ACK = 10
NETLINK_EXT_ACK = 11
NETLINK_GET_STRICT_CHK = 12
# Netlink message
NLMSG_ERROR = 2
NLMSG_DONE = 3
NLM_F_REQUEST = 1
NLM_F_ACK = 4
NLM_F_ROOT = 0x100
NLM_F_MATCH = 0x200
NLM_F_REPLACE = 0x100
NLM_F_EXCL = 0x200
NLM_F_CREATE = 0x400
NLM_F_APPEND = 0x800
NLM_F_CAPPED = 0x100
NLM_F_ACK_TLVS = 0x200
NLM_F_DUMP = NLM_F_ROOT | NLM_F_MATCH
NLA_F_NESTED = 0x8000
NLA_F_NET_BYTEORDER = 0x4000
NLA_TYPE_MASK = NLA_F_NESTED | NLA_F_NET_BYTEORDER
# Genetlink defines
NETLINK_GENERIC = 16
GENL_ID_CTRL = 0x10
# nlctrl
CTRL_CMD_GETFAMILY = 3
CTRL_ATTR_FAMILY_ID = 1
CTRL_ATTR_FAMILY_NAME = 2
CTRL_ATTR_MAXATTR = 5
CTRL_ATTR_MCAST_GROUPS = 7
CTRL_ATTR_MCAST_GRP_NAME = 1
CTRL_ATTR_MCAST_GRP_ID = 2
# Extack types
NLMSGERR_ATTR_MSG = 1
NLMSGERR_ATTR_OFFS = 2
NLMSGERR_ATTR_COOKIE = 3
NLMSGERR_ATTR_POLICY = 4
NLMSGERR_ATTR_MISS_TYPE = 5
NLMSGERR_ATTR_MISS_NEST = 6
# Policy types
NL_POLICY_TYPE_ATTR_TYPE = 1
NL_POLICY_TYPE_ATTR_MIN_VALUE_S = 2
NL_POLICY_TYPE_ATTR_MAX_VALUE_S = 3
NL_POLICY_TYPE_ATTR_MIN_VALUE_U = 4
NL_POLICY_TYPE_ATTR_MAX_VALUE_U = 5
NL_POLICY_TYPE_ATTR_MIN_LENGTH = 6
NL_POLICY_TYPE_ATTR_MAX_LENGTH = 7
NL_POLICY_TYPE_ATTR_POLICY_IDX = 8
NL_POLICY_TYPE_ATTR_POLICY_MAXTYPE = 9
NL_POLICY_TYPE_ATTR_BITFIELD32_MASK = 10
NL_POLICY_TYPE_ATTR_PAD = 11
NL_POLICY_TYPE_ATTR_MASK = 12
AttrType = Enum('AttrType', ['flag', 'u8', 'u16', 'u32', 'u64',
's8', 's16', 's32', 's64',
'binary', 'string', 'nul-string',
'nested', 'nested-array',
'bitfield32', 'sint', 'uint'])
class NlError(Exception):
def __init__(self, nl_msg):
self.nl_msg = nl_msg
self.error = -nl_msg.error
def __str__(self):
return f"Netlink error: {os.strerror(self.error)}\n{self.nl_msg}"
class ConfigError(Exception):
pass
class NlAttr:
ScalarFormat = namedtuple('ScalarFormat', ['native', 'big', 'little'])
type_formats = {
'u8' : ScalarFormat(Struct('B'), Struct("B"), Struct("B")),
's8' : ScalarFormat(Struct('b'), Struct("b"), Struct("b")),
'u16': ScalarFormat(Struct('H'), Struct(">H"), Struct("<H")),
's16': ScalarFormat(Struct('h'), Struct(">h"), Struct("<h")),
'u32': ScalarFormat(Struct('I'), Struct(">I"), Struct("<I")),
's32': ScalarFormat(Struct('i'), Struct(">i"), Struct("<i")),
'u64': ScalarFormat(Struct('Q'), Struct(">Q"), Struct("<Q")),
's64': ScalarFormat(Struct('q'), Struct(">q"), Struct("<q"))
}
def __init__(self, raw, offset):
self._len, self._type = struct.unpack("HH", raw[offset : offset + 4])
self.type = self._type & ~Netlink.NLA_TYPE_MASK
self.is_nest = self._type & Netlink.NLA_F_NESTED
self.payload_len = self._len
self.full_len = (self.payload_len + 3) & ~3
self.raw = raw[offset + 4 : offset + self.payload_len]
@classmethod
def get_format(cls, attr_type, byte_order=None):
format = cls.type_formats[attr_type]
if byte_order:
return format.big if byte_order == "big-endian" \
else format.little
return format.native
def as_scalar(self, attr_type, byte_order=None):
format = self.get_format(attr_type, byte_order)
return format.unpack(self.raw)[0]
def as_auto_scalar(self, attr_type, byte_order=None):
if len(self.raw) != 4 and len(self.raw) != 8:
raise Exception(f"Auto-scalar len payload be 4 or 8 bytes, got {len(self.raw)}")
real_type = attr_type[0] + str(len(self.raw) * 8)
format = self.get_format(real_type, byte_order)
return format.unpack(self.raw)[0]
def as_strz(self):
return self.raw.decode('ascii')[:-1]
def as_bin(self):
return self.raw
def as_c_array(self, type):
format = self.get_format(type)
return [ x[0] for x in format.iter_unpack(self.raw) ]
def __repr__(self):
return f"[type:{self.type} len:{self._len}] {self.raw}"
class NlAttrs:
def __init__(self, msg, offset=0):
self.attrs = []
while offset < len(msg):
attr = NlAttr(msg, offset)
offset += attr.full_len
self.attrs.append(attr)
def __iter__(self):
yield from self.attrs
def __repr__(self):
msg = ''
for a in self.attrs:
if msg:
msg += '\n'
msg += repr(a)
return msg
class NlMsg:
def __init__(self, msg, offset, attr_space=None):
self.hdr = msg[offset : offset + 16]
self.nl_len, self.nl_type, self.nl_flags, self.nl_seq, self.nl_portid = \
struct.unpack("IHHII", self.hdr)
self.raw = msg[offset + 16 : offset + self.nl_len]
self.error = 0
self.done = 0
extack_off = None
if self.nl_type == Netlink.NLMSG_ERROR:
self.error = struct.unpack("i", self.raw[0:4])[0]
self.done = 1
extack_off = 20
elif self.nl_type == Netlink.NLMSG_DONE:
self.error = struct.unpack("i", self.raw[0:4])[0]
self.done = 1
extack_off = 4
self.extack = None
if self.nl_flags & Netlink.NLM_F_ACK_TLVS and extack_off:
self.extack = dict()
extack_attrs = NlAttrs(self.raw[extack_off:])
for extack in extack_attrs:
if extack.type == Netlink.NLMSGERR_ATTR_MSG:
self.extack['msg'] = extack.as_strz()
elif extack.type == Netlink.NLMSGERR_ATTR_MISS_TYPE:
self.extack['miss-type'] = extack.as_scalar('u32')
elif extack.type == Netlink.NLMSGERR_ATTR_MISS_NEST:
self.extack['miss-nest'] = extack.as_scalar('u32')
elif extack.type == Netlink.NLMSGERR_ATTR_OFFS:
self.extack['bad-attr-offs'] = extack.as_scalar('u32')
elif extack.type == Netlink.NLMSGERR_ATTR_POLICY:
self.extack['policy'] = self._decode_policy(extack.raw)
else:
if 'unknown' not in self.extack:
self.extack['unknown'] = []
self.extack['unknown'].append(extack)
if attr_space:
# We don't have the ability to parse nests yet, so only do global
if 'miss-type' in self.extack and 'miss-nest' not in self.extack:
miss_type = self.extack['miss-type']
if miss_type in attr_space.attrs_by_val:
spec = attr_space.attrs_by_val[miss_type]
self.extack['miss-type'] = spec['name']
if 'doc' in spec:
self.extack['miss-type-doc'] = spec['doc']
def _decode_policy(self, raw):
policy = {}
for attr in NlAttrs(raw):
if attr.type == Netlink.NL_POLICY_TYPE_ATTR_TYPE:
type = attr.as_scalar('u32')
policy['type'] = Netlink.AttrType(type).name
elif attr.type == Netlink.NL_POLICY_TYPE_ATTR_MIN_VALUE_S:
policy['min-value'] = attr.as_scalar('s64')
elif attr.type == Netlink.NL_POLICY_TYPE_ATTR_MAX_VALUE_S:
policy['max-value'] = attr.as_scalar('s64')
elif attr.type == Netlink.NL_POLICY_TYPE_ATTR_MIN_VALUE_U:
policy['min-value'] = attr.as_scalar('u64')
elif attr.type == Netlink.NL_POLICY_TYPE_ATTR_MAX_VALUE_U:
policy['max-value'] = attr.as_scalar('u64')
elif attr.type == Netlink.NL_POLICY_TYPE_ATTR_MIN_LENGTH:
policy['min-length'] = attr.as_scalar('u32')
elif attr.type == Netlink.NL_POLICY_TYPE_ATTR_MAX_LENGTH:
policy['max-length'] = attr.as_scalar('u32')
elif attr.type == Netlink.NL_POLICY_TYPE_ATTR_BITFIELD32_MASK:
policy['bitfield32-mask'] = attr.as_scalar('u32')
elif attr.type == Netlink.NL_POLICY_TYPE_ATTR_MASK:
policy['mask'] = attr.as_scalar('u64')
return policy
def cmd(self):
return self.nl_type
def __repr__(self):
msg = f"nl_len = {self.nl_len} ({len(self.raw)}) nl_flags = 0x{self.nl_flags:x} nl_type = {self.nl_type}"
if self.error:
msg += '\n\terror: ' + str(self.error)
if self.extack:
msg += '\n\textack: ' + repr(self.extack)
return msg
class NlMsgs:
def __init__(self, data, attr_space=None):
self.msgs = []
offset = 0
while offset < len(data):
msg = NlMsg(data, offset, attr_space=attr_space)
offset += msg.nl_len
self.msgs.append(msg)
def __iter__(self):
yield from self.msgs
genl_family_name_to_id = None
def _genl_msg(nl_type, nl_flags, genl_cmd, genl_version, seq=None):
# we prepend length in _genl_msg_finalize()
if seq is None:
seq = random.randint(1, 1024)
nlmsg = struct.pack("HHII", nl_type, nl_flags, seq, 0)
genlmsg = struct.pack("BBH", genl_cmd, genl_version, 0)
return nlmsg + genlmsg
def _genl_msg_finalize(msg):
return struct.pack("I", len(msg) + 4) + msg
def _genl_load_families():
with socket.socket(socket.AF_NETLINK, socket.SOCK_RAW, Netlink.NETLINK_GENERIC) as sock:
sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_CAP_ACK, 1)
msg = _genl_msg(Netlink.GENL_ID_CTRL,
Netlink.NLM_F_REQUEST | Netlink.NLM_F_ACK | Netlink.NLM_F_DUMP,
Netlink.CTRL_CMD_GETFAMILY, 1)
msg = _genl_msg_finalize(msg)
sock.send(msg, 0)
global genl_family_name_to_id
genl_family_name_to_id = dict()
while True:
reply = sock.recv(128 * 1024)
nms = NlMsgs(reply)
for nl_msg in nms:
if nl_msg.error:
print("Netlink error:", nl_msg.error)
return
if nl_msg.done:
return
gm = GenlMsg(nl_msg)
fam = dict()
for attr in NlAttrs(gm.raw):
if attr.type == Netlink.CTRL_ATTR_FAMILY_ID:
fam['id'] = attr.as_scalar('u16')
elif attr.type == Netlink.CTRL_ATTR_FAMILY_NAME:
fam['name'] = attr.as_strz()
elif attr.type == Netlink.CTRL_ATTR_MAXATTR:
fam['maxattr'] = attr.as_scalar('u32')
elif attr.type == Netlink.CTRL_ATTR_MCAST_GROUPS:
fam['mcast'] = dict()
for entry in NlAttrs(attr.raw):
mcast_name = None
mcast_id = None
for entry_attr in NlAttrs(entry.raw):
if entry_attr.type == Netlink.CTRL_ATTR_MCAST_GRP_NAME:
mcast_name = entry_attr.as_strz()
elif entry_attr.type == Netlink.CTRL_ATTR_MCAST_GRP_ID:
mcast_id = entry_attr.as_scalar('u32')
if mcast_name and mcast_id is not None:
fam['mcast'][mcast_name] = mcast_id
if 'name' in fam and 'id' in fam:
genl_family_name_to_id[fam['name']] = fam
class GenlMsg:
def __init__(self, nl_msg):
self.nl = nl_msg
self.genl_cmd, self.genl_version, _ = struct.unpack_from("BBH", nl_msg.raw, 0)
self.raw = nl_msg.raw[4:]
def cmd(self):
return self.genl_cmd
def __repr__(self):
msg = repr(self.nl)
msg += f"\tgenl_cmd = {self.genl_cmd} genl_ver = {self.genl_version}\n"
for a in self.raw_attrs:
msg += '\t\t' + repr(a) + '\n'
return msg
class NetlinkProtocol:
def __init__(self, family_name, proto_num):
self.family_name = family_name
self.proto_num = proto_num
def _message(self, nl_type, nl_flags, seq=None):
if seq is None:
seq = random.randint(1, 1024)
nlmsg = struct.pack("HHII", nl_type, nl_flags, seq, 0)
return nlmsg
def message(self, flags, command, version, seq=None):
return self._message(command, flags, seq)
def _decode(self, nl_msg):
return nl_msg
def decode(self, ynl, nl_msg, op):
msg = self._decode(nl_msg)
if op is None:
op = ynl.rsp_by_value[msg.cmd()]
fixed_header_size = ynl._struct_size(op.fixed_header)
msg.raw_attrs = NlAttrs(msg.raw, fixed_header_size)
return msg
def get_mcast_id(self, mcast_name, mcast_groups):
if mcast_name not in mcast_groups:
raise Exception(f'Multicast group "{mcast_name}" not present in the spec')
return mcast_groups[mcast_name].value
def msghdr_size(self):
return 16
class GenlProtocol(NetlinkProtocol):
def __init__(self, family_name):
super().__init__(family_name, Netlink.NETLINK_GENERIC)
global genl_family_name_to_id
if genl_family_name_to_id is None:
_genl_load_families()
self.genl_family = genl_family_name_to_id[family_name]
self.family_id = genl_family_name_to_id[family_name]['id']
def message(self, flags, command, version, seq=None):
nlmsg = self._message(self.family_id, flags, seq)
genlmsg = struct.pack("BBH", command, version, 0)
return nlmsg + genlmsg
def _decode(self, nl_msg):
return GenlMsg(nl_msg)
def get_mcast_id(self, mcast_name, mcast_groups):
if mcast_name not in self.genl_family['mcast']:
raise Exception(f'Multicast group "{mcast_name}" not present in the family')
return self.genl_family['mcast'][mcast_name]
def msghdr_size(self):
return super().msghdr_size() + 4
class SpaceAttrs:
SpecValuesPair = namedtuple('SpecValuesPair', ['spec', 'values'])
def __init__(self, attr_space, attrs, outer = None):
outer_scopes = outer.scopes if outer else []
inner_scope = self.SpecValuesPair(attr_space, attrs)
self.scopes = [inner_scope] + outer_scopes
def lookup(self, name):
for scope in self.scopes:
if name in scope.spec:
if name in scope.values:
return scope.values[name]
spec_name = scope.spec.yaml['name']
raise Exception(
f"No value for '{name}' in attribute space '{spec_name}'")
raise Exception(f"Attribute '{name}' not defined in any attribute-set")
#
# YNL implementation details.
#
class YnlFamily(SpecFamily):
def __init__(self, def_path, schema=None, process_unknown=False,
recv_size=0):
super().__init__(def_path, schema)
self.include_raw = False
self.process_unknown = process_unknown
try:
if self.proto == "netlink-raw":
self.nlproto = NetlinkProtocol(self.yaml['name'],
self.yaml['protonum'])
else:
self.nlproto = GenlProtocol(self.yaml['name'])
except KeyError:
raise Exception(f"Family '{self.yaml['name']}' not supported by the kernel")
self._recv_dbg = False
# Note that netlink will use conservative (min) message size for
# the first dump recv() on the socket, our setting will only matter
# from the second recv() on.
self._recv_size = recv_size if recv_size else 131072
# Netlink will always allocate at least PAGE_SIZE - sizeof(skb_shinfo)
# for a message, so smaller receive sizes will lead to truncation.
# Note that the min size for other families may be larger than 4k!
if self._recv_size < 4000:
raise ConfigError()
self.sock = socket.socket(socket.AF_NETLINK, socket.SOCK_RAW, self.nlproto.proto_num)
self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_CAP_ACK, 1)
self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_EXT_ACK, 1)
self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_GET_STRICT_CHK, 1)
self.async_msg_ids = set()
self.async_msg_queue = []
for msg in self.msgs.values():
if msg.is_async:
self.async_msg_ids.add(msg.rsp_value)
for op_name, op in self.ops.items():
bound_f = functools.partial(self._op, op_name)
setattr(self, op.ident_name, bound_f)
def ntf_subscribe(self, mcast_name):
mcast_id = self.nlproto.get_mcast_id(mcast_name, self.mcast_groups)
self.sock.bind((0, 0))
self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_ADD_MEMBERSHIP,
mcast_id)
def set_recv_dbg(self, enabled):
self._recv_dbg = enabled
def _recv_dbg_print(self, reply, nl_msgs):
if not self._recv_dbg:
return
print("Recv: read", len(reply), "bytes,",
len(nl_msgs.msgs), "messages", file=sys.stderr)
for nl_msg in nl_msgs:
print(" ", nl_msg, file=sys.stderr)
def _encode_enum(self, attr_spec, value):
enum = self.consts[attr_spec['enum']]
if enum.type == 'flags' or attr_spec.get('enum-as-flags', False):
scalar = 0
if isinstance(value, str):
value = [value]
for single_value in value:
scalar += enum.entries[single_value].user_value(as_flags = True)
return scalar
else:
return enum.entries[value].user_value()
def _get_scalar(self, attr_spec, value):
try:
return int(value)
except (ValueError, TypeError) as e:
if 'enum' not in attr_spec:
raise e
return self._encode_enum(attr_spec, value)
def _add_attr(self, space, name, value, search_attrs):
try:
attr = self.attr_sets[space][name]
except KeyError:
raise Exception(f"Space '{space}' has no attribute '{name}'")
nl_type = attr.value
if attr.is_multi and isinstance(value, list):
attr_payload = b''
for subvalue in value:
attr_payload += self._add_attr(space, name, subvalue, search_attrs)
return attr_payload
if attr["type"] == 'nest':
nl_type |= Netlink.NLA_F_NESTED
attr_payload = b''
sub_attrs = SpaceAttrs(self.attr_sets[space], value, search_attrs)
for subname, subvalue in value.items():
attr_payload += self._add_attr(attr['nested-attributes'],
subname, subvalue, sub_attrs)
elif attr["type"] == 'flag':
if not value:
# If value is absent or false then skip attribute creation.
return b''
attr_payload = b''
elif attr["type"] == 'string':
attr_payload = str(value).encode('ascii') + b'\x00'
elif attr["type"] == 'binary':
if isinstance(value, bytes):
attr_payload = value
elif isinstance(value, str):
attr_payload = bytes.fromhex(value)
elif isinstance(value, dict) and attr.struct_name:
attr_payload = self._encode_struct(attr.struct_name, value)
else:
raise Exception(f'Unknown type for binary attribute, value: {value}')
elif attr['type'] in NlAttr.type_formats or attr.is_auto_scalar:
scalar = self._get_scalar(attr, value)
if attr.is_auto_scalar:
attr_type = attr["type"][0] + ('32' if scalar.bit_length() <= 32 else '64')
else:
attr_type = attr["type"]
format = NlAttr.get_format(attr_type, attr.byte_order)
attr_payload = format.pack(scalar)
elif attr['type'] in "bitfield32":
scalar_value = self._get_scalar(attr, value["value"])
scalar_selector = self._get_scalar(attr, value["selector"])
attr_payload = struct.pack("II", scalar_value, scalar_selector)
elif attr['type'] == 'sub-message':
msg_format = self._resolve_selector(attr, search_attrs)
attr_payload = b''
if msg_format.fixed_header:
attr_payload += self._encode_struct(msg_format.fixed_header, value)
if msg_format.attr_set:
if msg_format.attr_set in self.attr_sets:
nl_type |= Netlink.NLA_F_NESTED
sub_attrs = SpaceAttrs(msg_format.attr_set, value, search_attrs)
for subname, subvalue in value.items():
attr_payload += self._add_attr(msg_format.attr_set,
subname, subvalue, sub_attrs)
else:
raise Exception(f"Unknown attribute-set '{msg_format.attr_set}'")
else:
raise Exception(f'Unknown type at {space} {name} {value} {attr["type"]}')
pad = b'\x00' * ((4 - len(attr_payload) % 4) % 4)
return struct.pack('HH', len(attr_payload) + 4, nl_type) + attr_payload + pad
def _decode_enum(self, raw, attr_spec):
enum = self.consts[attr_spec['enum']]
if enum.type == 'flags' or attr_spec.get('enum-as-flags', False):
i = 0
value = set()
while raw:
if raw & 1:
value.add(enum.entries_by_val[i].name)
raw >>= 1
i += 1
else:
value = enum.entries_by_val[raw].name
return value
def _decode_binary(self, attr, attr_spec):
if attr_spec.struct_name:
decoded = self._decode_struct(attr.raw, attr_spec.struct_name)
elif attr_spec.sub_type:
decoded = attr.as_c_array(attr_spec.sub_type)
else:
decoded = attr.as_bin()
if attr_spec.display_hint:
decoded = self._formatted_string(decoded, attr_spec.display_hint)
return decoded
def _decode_array_attr(self, attr, attr_spec):
decoded = []
offset = 0
while offset < len(attr.raw):
item = NlAttr(attr.raw, offset)
offset += item.full_len
if attr_spec["sub-type"] == 'nest':
subattrs = self._decode(NlAttrs(item.raw), attr_spec['nested-attributes'])
decoded.append({ item.type: subattrs })
elif attr_spec["sub-type"] == 'binary':
subattrs = item.as_bin()
if attr_spec.display_hint:
subattrs = self._formatted_string(subattrs, attr_spec.display_hint)
decoded.append(subattrs)
elif attr_spec["sub-type"] in NlAttr.type_formats:
subattrs = item.as_scalar(attr_spec['sub-type'], attr_spec.byte_order)
if attr_spec.display_hint:
subattrs = self._formatted_string(subattrs, attr_spec.display_hint)
decoded.append(subattrs)
else:
raise Exception(f'Unknown {attr_spec["sub-type"]} with name {attr_spec["name"]}')
return decoded
def _decode_nest_type_value(self, attr, attr_spec):
decoded = {}
value = attr
for name in attr_spec['type-value']:
value = NlAttr(value.raw, 0)
decoded[name] = value.type
subattrs = self._decode(NlAttrs(value.raw), attr_spec['nested-attributes'])
decoded.update(subattrs)
return decoded
def _decode_unknown(self, attr):
if attr.is_nest:
return self._decode(NlAttrs(attr.raw), None)
else:
return attr.as_bin()
def _rsp_add(self, rsp, name, is_multi, decoded):
if is_multi == None:
if name in rsp and type(rsp[name]) is not list:
rsp[name] = [rsp[name]]
is_multi = True
else:
is_multi = False
if not is_multi:
rsp[name] = decoded
elif name in rsp:
rsp[name].append(decoded)
else:
rsp[name] = [decoded]
def _resolve_selector(self, attr_spec, search_attrs):
sub_msg = attr_spec.sub_message
if sub_msg not in self.sub_msgs:
raise Exception(f"No sub-message spec named {sub_msg} for {attr_spec.name}")
sub_msg_spec = self.sub_msgs[sub_msg]
selector = attr_spec.selector
value = search_attrs.lookup(selector)
if value not in sub_msg_spec.formats:
raise Exception(f"No message format for '{value}' in sub-message spec '{sub_msg}'")
spec = sub_msg_spec.formats[value]
return spec
def _decode_sub_msg(self, attr, attr_spec, search_attrs):
msg_format = self._resolve_selector(attr_spec, search_attrs)
decoded = {}
offset = 0
if msg_format.fixed_header:
decoded.update(self._decode_struct(attr.raw, msg_format.fixed_header));
offset = self._struct_size(msg_format.fixed_header)
if msg_format.attr_set:
if msg_format.attr_set in self.attr_sets:
subdict = self._decode(NlAttrs(attr.raw, offset), msg_format.attr_set)
decoded.update(subdict)
else:
raise Exception(f"Unknown attribute-set '{attr_space}' when decoding '{attr_spec.name}'")
return decoded
def _decode(self, attrs, space, outer_attrs = None):
rsp = dict()
if space:
attr_space = self.attr_sets[space]
search_attrs = SpaceAttrs(attr_space, rsp, outer_attrs)
for attr in attrs:
try:
attr_spec = attr_space.attrs_by_val[attr.type]
except (KeyError, UnboundLocalError):
if not self.process_unknown:
raise Exception(f"Space '{space}' has no attribute with value '{attr.type}'")
attr_name = f"UnknownAttr({attr.type})"
self._rsp_add(rsp, attr_name, None, self._decode_unknown(attr))
continue
if attr_spec["type"] == 'nest':
subdict = self._decode(NlAttrs(attr.raw), attr_spec['nested-attributes'], search_attrs)
decoded = subdict
elif attr_spec["type"] == 'string':
decoded = attr.as_strz()
elif attr_spec["type"] == 'binary':
decoded = self._decode_binary(attr, attr_spec)
elif attr_spec["type"] == 'flag':
decoded = True
elif attr_spec.is_auto_scalar:
decoded = attr.as_auto_scalar(attr_spec['type'], attr_spec.byte_order)
elif attr_spec["type"] in NlAttr.type_formats:
decoded = attr.as_scalar(attr_spec['type'], attr_spec.byte_order)
if 'enum' in attr_spec:
decoded = self._decode_enum(decoded, attr_spec)
elif attr_spec.display_hint:
decoded = self._formatted_string(decoded, attr_spec.display_hint)
elif attr_spec["type"] == 'indexed-array':
decoded = self._decode_array_attr(attr, attr_spec)
elif attr_spec["type"] == 'bitfield32':
value, selector = struct.unpack("II", attr.raw)
if 'enum' in attr_spec:
value = self._decode_enum(value, attr_spec)
selector = self._decode_enum(selector, attr_spec)
decoded = {"value": value, "selector": selector}
elif attr_spec["type"] == 'sub-message':
decoded = self._decode_sub_msg(attr, attr_spec, search_attrs)
elif attr_spec["type"] == 'nest-type-value':
decoded = self._decode_nest_type_value(attr, attr_spec)
else:
if not self.process_unknown:
raise Exception(f'Unknown {attr_spec["type"]} with name {attr_spec["name"]}')
decoded = self._decode_unknown(attr)
self._rsp_add(rsp, attr_spec["name"], attr_spec.is_multi, decoded)
return rsp
def _decode_extack_path(self, attrs, attr_set, offset, target):
for attr in attrs:
try:
attr_spec = attr_set.attrs_by_val[attr.type]
except KeyError:
raise Exception(f"Space '{attr_set.name}' has no attribute with value '{attr.type}'")
if offset > target:
break
if offset == target:
return '.' + attr_spec.name
if offset + attr.full_len <= target:
offset += attr.full_len
continue
if attr_spec['type'] != 'nest':
raise Exception(f"Can't dive into {attr.type} ({attr_spec['name']}) for extack")
offset += 4
subpath = self._decode_extack_path(NlAttrs(attr.raw),
self.attr_sets[attr_spec['nested-attributes']],
offset, target)
if subpath is None:
return None
return '.' + attr_spec.name + subpath
return None
def _decode_extack(self, request, op, extack):
if 'bad-attr-offs' not in extack:
return
msg = self.nlproto.decode(self, NlMsg(request, 0, op.attr_set), op)
offset = self.nlproto.msghdr_size() + self._struct_size(op.fixed_header)
path = self._decode_extack_path(msg.raw_attrs, op.attr_set, offset,
extack['bad-attr-offs'])
if path:
del extack['bad-attr-offs']
extack['bad-attr'] = path
def _struct_size(self, name):
if name:
members = self.consts[name].members
size = 0
for m in members:
if m.type in ['pad', 'binary']:
if m.struct:
size += self._struct_size(m.struct)
else:
size += m.len
else:
format = NlAttr.get_format(m.type, m.byte_order)
size += format.size
return size
else:
return 0
def _decode_struct(self, data, name):
members = self.consts[name].members
attrs = dict()
offset = 0
for m in members:
value = None
if m.type == 'pad':
offset += m.len
elif m.type == 'binary':
if m.struct:
len = self._struct_size(m.struct)
value = self._decode_struct(data[offset : offset + len],
m.struct)
offset += len
else:
value = data[offset : offset + m.len]
offset += m.len
else:
format = NlAttr.get_format(m.type, m.byte_order)
[ value ] = format.unpack_from(data, offset)
offset += format.size
if value is not None:
if m.enum:
value = self._decode_enum(value, m)
elif m.display_hint:
value = self._formatted_string(value, m.display_hint)
attrs[m.name] = value
return attrs
def _encode_struct(self, name, vals):
members = self.consts[name].members
attr_payload = b''
for m in members:
value = vals.pop(m.name) if m.name in vals else None
if m.type == 'pad':
attr_payload += bytearray(m.len)
elif m.type == 'binary':
if m.struct:
if value is None:
value = dict()
attr_payload += self._encode_struct(m.struct, value)
else:
if value is None:
attr_payload += bytearray(m.len)
else:
attr_payload += bytes.fromhex(value)
else:
if value is None:
value = 0
format = NlAttr.get_format(m.type, m.byte_order)
attr_payload += format.pack(value)
return attr_payload
def _formatted_string(self, raw, display_hint):
if display_hint == 'mac':
formatted = ':'.join('%02x' % b for b in raw)
elif display_hint == 'hex':
if isinstance(raw, int):
formatted = hex(raw)
else:
formatted = bytes.hex(raw, ' ')
elif display_hint in [ 'ipv4', 'ipv6' ]:
formatted = format(ipaddress.ip_address(raw))
elif display_hint == 'uuid':
formatted = str(uuid.UUID(bytes=raw))
else:
formatted = raw
return formatted
def handle_ntf(self, decoded):
msg = dict()
if self.include_raw:
msg['raw'] = decoded
op = self.rsp_by_value[decoded.cmd()]
attrs = self._decode(decoded.raw_attrs, op.attr_set.name)
if op.fixed_header:
attrs.update(self._decode_struct(decoded.raw, op.fixed_header))
msg['name'] = op['name']
msg['msg'] = attrs
self.async_msg_queue.append(msg)
def check_ntf(self):
while True:
try:
reply = self.sock.recv(self._recv_size, socket.MSG_DONTWAIT)
except BlockingIOError:
return
nms = NlMsgs(reply)
self._recv_dbg_print(reply, nms)
for nl_msg in nms:
if nl_msg.error:
print("Netlink error in ntf!?", os.strerror(-nl_msg.error))
print(nl_msg)
continue
if nl_msg.done:
print("Netlink done while checking for ntf!?")
continue
decoded = self.nlproto.decode(self, nl_msg, None)
if decoded.cmd() not in self.async_msg_ids:
print("Unexpected msg id done while checking for ntf", decoded)
continue
self.handle_ntf(decoded)
def operation_do_attributes(self, name):
"""
For a given operation name, find and return a supported
set of attributes (as a dict).
"""
op = self.find_operation(name)
if not op:
return None
return op['do']['request']['attributes'].copy()
def _encode_message(self, op, vals, flags, req_seq):
nl_flags = Netlink.NLM_F_REQUEST | Netlink.NLM_F_ACK
for flag in flags or []:
nl_flags |= flag
msg = self.nlproto.message(nl_flags, op.req_value, 1, req_seq)
if op.fixed_header:
msg += self._encode_struct(op.fixed_header, vals)
search_attrs = SpaceAttrs(op.attr_set, vals)
for name, value in vals.items():
msg += self._add_attr(op.attr_set.name, name, value, search_attrs)
msg = _genl_msg_finalize(msg)
return msg
def _ops(self, ops):
reqs_by_seq = {}
req_seq = random.randint(1024, 65535)
payload = b''
for (method, vals, flags) in ops:
op = self.ops[method]
msg = self._encode_message(op, vals, flags, req_seq)
reqs_by_seq[req_seq] = (op, msg, flags)
payload += msg
req_seq += 1
self.sock.send(payload, 0)
done = False
rsp = []
op_rsp = []
while not done:
reply = self.sock.recv(self._recv_size)
nms = NlMsgs(reply, attr_space=op.attr_set)
self._recv_dbg_print(reply, nms)
for nl_msg in nms:
if nl_msg.nl_seq in reqs_by_seq:
(op, req_msg, req_flags) = reqs_by_seq[nl_msg.nl_seq]
if nl_msg.extack:
self._decode_extack(req_msg, op, nl_msg.extack)
else:
op = None
req_flags = []
if nl_msg.error:
raise NlError(nl_msg)
if nl_msg.done:
if nl_msg.extack:
print("Netlink warning:")
print(nl_msg)
if Netlink.NLM_F_DUMP in req_flags:
rsp.append(op_rsp)
elif not op_rsp:
rsp.append(None)
elif len(op_rsp) == 1:
rsp.append(op_rsp[0])
else:
rsp.append(op_rsp)
op_rsp = []
del reqs_by_seq[nl_msg.nl_seq]
done = len(reqs_by_seq) == 0
break
decoded = self.nlproto.decode(self, nl_msg, op)
# Check if this is a reply to our request
if nl_msg.nl_seq not in reqs_by_seq or decoded.cmd() != op.rsp_value:
if decoded.cmd() in self.async_msg_ids:
self.handle_ntf(decoded)
continue
else:
print('Unexpected message: ' + repr(decoded))
continue
rsp_msg = self._decode(decoded.raw_attrs, op.attr_set.name)
if op.fixed_header:
rsp_msg.update(self._decode_struct(decoded.raw, op.fixed_header))
op_rsp.append(rsp_msg)
return rsp
def _op(self, method, vals, flags=None, dump=False):
req_flags = flags or []
if dump:
req_flags.append(Netlink.NLM_F_DUMP)
ops = [(method, vals, req_flags)]
return self._ops(ops)[0]
def do(self, method, vals, flags=None):
return self._op(method, vals, flags)
def dump(self, method, vals):
return self._op(method, vals, dump=True)
def do_multi(self, ops):
return self._ops(ops)
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