| # SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause |
| |
| import functools |
| import os |
| import random |
| import socket |
| import struct |
| import yaml |
| |
| 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 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_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 |
| |
| |
| class NlError(Exception): |
| def __init__(self, nl_msg): |
| self.nl_msg = nl_msg |
| |
| def __str__(self): |
| return f"Netlink error: {os.strerror(-self.nl_msg.error)}\n{self.nl_msg}" |
| |
| |
| class NlAttr: |
| type_formats = { 'u8' : ('B', 1), 's8' : ('b', 1), |
| 'u16': ('H', 2), 's16': ('h', 2), |
| 'u32': ('I', 4), 's32': ('i', 4), |
| 'u64': ('Q', 8), 's64': ('q', 8) } |
| |
| 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.payload_len = self._len |
| self.full_len = (self.payload_len + 3) & ~3 |
| self.raw = raw[offset + 4:offset + self.payload_len] |
| |
| def format_byte_order(byte_order): |
| if byte_order: |
| return ">" if byte_order == "big-endian" else "<" |
| return "" |
| |
| def as_u8(self): |
| return struct.unpack("B", self.raw)[0] |
| |
| def as_u16(self, byte_order=None): |
| endian = NlAttr.format_byte_order(byte_order) |
| return struct.unpack(f"{endian}H", self.raw)[0] |
| |
| def as_u32(self, byte_order=None): |
| endian = NlAttr.format_byte_order(byte_order) |
| return struct.unpack(f"{endian}I", self.raw)[0] |
| |
| def as_u64(self, byte_order=None): |
| endian = NlAttr.format_byte_order(byte_order) |
| return struct.unpack(f"{endian}Q", 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.type_formats[type] |
| return list({ x[0] for x in struct.iter_unpack(format, self.raw) }) |
| |
| def as_struct(self, members): |
| value = dict() |
| offset = 0 |
| for m in members: |
| # TODO: handle non-scalar members |
| format, size = self.type_formats[m.type] |
| decoded = struct.unpack_from(format, self.raw, offset) |
| offset += size |
| value[m.name] = decoded[0] |
| return value |
| |
| def __repr__(self): |
| return f"[type:{self.type} len:{self._len}] {self.raw}" |
| |
| |
| class NlAttrs: |
| def __init__(self, msg): |
| self.attrs = [] |
| |
| offset = 0 |
| 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.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_u32() |
| elif extack.type == Netlink.NLMSGERR_ATTR_MISS_NEST: |
| self.extack['miss-nest'] = extack.as_u32() |
| elif extack.type == Netlink.NLMSGERR_ATTR_OFFS: |
| self.extack['bad-attr-offs'] = extack.as_u32() |
| 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] |
| desc = spec['name'] |
| if 'doc' in spec: |
| desc += f" ({spec['doc']})" |
| self.extack['miss-type'] = desc |
| |
| 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}\n" |
| if self.error: |
| msg += '\terror: ' + str(self.error) |
| if self.extack: |
| msg += '\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 gm.raw_attrs: |
| if attr.type == Netlink.CTRL_ATTR_FAMILY_ID: |
| fam['id'] = attr.as_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_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_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, fixed_header_members=[]): |
| self.nl = nl_msg |
| |
| self.hdr = nl_msg.raw[0:4] |
| offset = 4 |
| |
| self.genl_cmd, self.genl_version, _ = struct.unpack("BBH", self.hdr) |
| |
| self.fixed_header_attrs = dict() |
| for m in fixed_header_members: |
| format, size = NlAttr.type_formats[m.type] |
| decoded = struct.unpack_from(format, nl_msg.raw, offset) |
| offset += size |
| self.fixed_header_attrs[m.name] = decoded[0] |
| |
| self.raw = nl_msg.raw[offset:] |
| self.raw_attrs = NlAttrs(self.raw) |
| |
| 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 GenlFamily: |
| def __init__(self, family_name): |
| self.family_name = family_name |
| |
| 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'] |
| |
| |
| # |
| # YNL implementation details. |
| # |
| |
| |
| class YnlFamily(SpecFamily): |
| def __init__(self, def_path, schema=None): |
| super().__init__(def_path, schema) |
| |
| self.include_raw = False |
| |
| self.sock = socket.socket(socket.AF_NETLINK, socket.SOCK_RAW, Netlink.NETLINK_GENERIC) |
| self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_CAP_ACK, 1) |
| self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_EXT_ACK, 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) |
| |
| try: |
| self.family = GenlFamily(self.yaml['name']) |
| except KeyError: |
| raise Exception(f"Family '{self.yaml['name']}' not supported by the kernel") |
| |
| def ntf_subscribe(self, mcast_name): |
| if mcast_name not in self.family.genl_family['mcast']: |
| raise Exception(f'Multicast group "{mcast_name}" not present in the family') |
| |
| self.sock.bind((0, 0)) |
| self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_ADD_MEMBERSHIP, |
| self.family.genl_family['mcast'][mcast_name]) |
| |
| def _add_attr(self, space, name, value): |
| attr = self.attr_sets[space][name] |
| nl_type = attr.value |
| if attr["type"] == 'nest': |
| nl_type |= Netlink.NLA_F_NESTED |
| attr_payload = b'' |
| for subname, subvalue in value.items(): |
| attr_payload += self._add_attr(attr['nested-attributes'], subname, subvalue) |
| elif attr["type"] == 'flag': |
| attr_payload = b'' |
| elif attr["type"] == 'u8': |
| attr_payload = struct.pack("B", int(value)) |
| elif attr["type"] == 'u16': |
| endian = NlAttr.format_byte_order(attr.byte_order) |
| attr_payload = struct.pack(f"{endian}H", int(value)) |
| elif attr["type"] == 'u32': |
| endian = NlAttr.format_byte_order(attr.byte_order) |
| attr_payload = struct.pack(f"{endian}I", int(value)) |
| elif attr["type"] == 'u64': |
| endian = NlAttr.format_byte_order(attr.byte_order) |
| attr_payload = struct.pack(f"{endian}Q", int(value)) |
| elif attr["type"] == 'string': |
| attr_payload = str(value).encode('ascii') + b'\x00' |
| elif attr["type"] == 'binary': |
| attr_payload = value |
| 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, rsp, attr_spec): |
| raw = rsp[attr_spec['name']] |
| enum = self.consts[attr_spec['enum']] |
| i = attr_spec.get('value-start', 0) |
| if 'enum-as-flags' in attr_spec and attr_spec['enum-as-flags']: |
| 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 - i].name |
| rsp[attr_spec['name']] = value |
| |
| def _decode_binary(self, attr, attr_spec): |
| if attr_spec.struct_name: |
| decoded = attr.as_struct(self.consts[attr_spec.struct_name]) |
| elif attr_spec.sub_type: |
| decoded = attr.as_c_array(attr_spec.sub_type) |
| else: |
| decoded = attr.as_bin() |
| return decoded |
| |
| def _decode(self, attrs, space): |
| attr_space = self.attr_sets[space] |
| rsp = dict() |
| for attr in attrs: |
| attr_spec = attr_space.attrs_by_val[attr.type] |
| if attr_spec["type"] == 'nest': |
| subdict = self._decode(NlAttrs(attr.raw), attr_spec['nested-attributes']) |
| decoded = subdict |
| elif attr_spec['type'] == 'u8': |
| decoded = attr.as_u8() |
| elif attr_spec['type'] == 'u16': |
| decoded = attr.as_u16(attr_spec.byte_order) |
| elif attr_spec['type'] == 'u32': |
| decoded = attr.as_u32(attr_spec.byte_order) |
| elif attr_spec['type'] == 'u64': |
| decoded = attr.as_u64(attr_spec.byte_order) |
| 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 |
| else: |
| raise Exception(f'Unknown {attr.type} {attr_spec["name"]} {attr_spec["type"]}') |
| |
| if not attr_spec.is_multi: |
| rsp[attr_spec['name']] = decoded |
| elif attr_spec.name in rsp: |
| rsp[attr_spec.name].append(decoded) |
| else: |
| rsp[attr_spec.name] = [decoded] |
| |
| if 'enum' in attr_spec: |
| self._decode_enum(rsp, attr_spec) |
| return rsp |
| |
| def _decode_extack_path(self, attrs, attr_set, offset, target): |
| for attr in attrs: |
| attr_spec = attr_set.attrs_by_val[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, attr_space, extack): |
| if 'bad-attr-offs' not in extack: |
| return |
| |
| genl_req = GenlMsg(NlMsg(request, 0, attr_space=attr_space)) |
| path = self._decode_extack_path(genl_req.raw_attrs, attr_space, |
| 20, extack['bad-attr-offs']) |
| if path: |
| del extack['bad-attr-offs'] |
| extack['bad-attr'] = path |
| |
| def handle_ntf(self, nl_msg, genl_msg): |
| msg = dict() |
| if self.include_raw: |
| msg['nlmsg'] = nl_msg |
| msg['genlmsg'] = genl_msg |
| op = self.rsp_by_value[genl_msg.genl_cmd] |
| msg['name'] = op['name'] |
| msg['msg'] = self._decode(genl_msg.raw_attrs, op.attr_set.name) |
| self.async_msg_queue.append(msg) |
| |
| def check_ntf(self): |
| while True: |
| try: |
| reply = self.sock.recv(128 * 1024, socket.MSG_DONTWAIT) |
| except BlockingIOError: |
| return |
| |
| nms = NlMsgs(reply) |
| 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 |
| |
| gm = GenlMsg(nl_msg) |
| if gm.genl_cmd not in self.async_msg_ids: |
| print("Unexpected msg id done while checking for ntf", gm) |
| continue |
| |
| self.handle_ntf(nl_msg, gm) |
| |
| 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 _op(self, method, vals, dump=False): |
| op = self.ops[method] |
| |
| nl_flags = Netlink.NLM_F_REQUEST | Netlink.NLM_F_ACK |
| if dump: |
| nl_flags |= Netlink.NLM_F_DUMP |
| |
| req_seq = random.randint(1024, 65535) |
| msg = _genl_msg(self.family.family_id, nl_flags, op.req_value, 1, req_seq) |
| fixed_header_members = [] |
| if op.fixed_header: |
| fixed_header_members = self.consts[op.fixed_header].members |
| for m in fixed_header_members: |
| value = vals.pop(m.name) |
| format, _ = NlAttr.type_formats[m.type] |
| msg += struct.pack(format, value) |
| for name, value in vals.items(): |
| msg += self._add_attr(op.attr_set.name, name, value) |
| msg = _genl_msg_finalize(msg) |
| |
| self.sock.send(msg, 0) |
| |
| done = False |
| rsp = [] |
| while not done: |
| reply = self.sock.recv(128 * 1024) |
| nms = NlMsgs(reply, attr_space=op.attr_set) |
| for nl_msg in nms: |
| if nl_msg.extack: |
| self._decode_extack(msg, op.attr_set, nl_msg.extack) |
| |
| if nl_msg.error: |
| raise NlError(nl_msg) |
| if nl_msg.done: |
| if nl_msg.extack: |
| print("Netlink warning:") |
| print(nl_msg) |
| done = True |
| break |
| |
| gm = GenlMsg(nl_msg, fixed_header_members) |
| # Check if this is a reply to our request |
| if nl_msg.nl_seq != req_seq or gm.genl_cmd != op.rsp_value: |
| if gm.genl_cmd in self.async_msg_ids: |
| self.handle_ntf(nl_msg, gm) |
| continue |
| else: |
| print('Unexpected message: ' + repr(gm)) |
| continue |
| |
| rsp_msg = self._decode(gm.raw_attrs, op.attr_set.name) |
| rsp_msg.update(gm.fixed_header_attrs) |
| rsp.append(rsp_msg) |
| |
| if not rsp: |
| return None |
| if not dump and len(rsp) == 1: |
| return rsp[0] |
| return rsp |
| |
| def do(self, method, vals): |
| return self._op(method, vals) |
| |
| def dump(self, method, vals): |
| return self._op(method, vals, dump=True) |
