diff options
Diffstat (limited to 'tools/net/ynl/lib/ynl.py')
| -rw-r--r-- | tools/net/ynl/lib/ynl.py | 528 |
1 files changed, 528 insertions, 0 deletions
diff --git a/tools/net/ynl/lib/ynl.py b/tools/net/ynl/lib/ynl.py new file mode 100644 index 000000000000..1c7411ee04dc --- /dev/null +++ b/tools/net/ynl/lib/ynl.py @@ -0,0 +1,528 @@ +# SPDX-License-Identifier: 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 NlAttr: + 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 as_u8(self): + return struct.unpack("B", self.raw)[0] + + def as_u16(self): + return struct.unpack("H", self.raw)[0] + + def as_u32(self): + return struct.unpack("I", self.raw)[0] + + def as_u64(self): + return struct.unpack("Q", self.raw)[0] + + def as_strz(self): + return self.raw.decode('ascii')[:-1] + + def as_bin(self): + return self.raw + + 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): + self.nl = nl_msg + + self.hdr = nl_msg.raw[0:4] + self.raw = nl_msg.raw[4:] + + self.genl_cmd, self.genl_version, _ = struct.unpack("bbH", self.hdr) + + 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._types = dict() + + for elem in self.yaml.get('definitions', []): + self._types[elem['name']] = elem + + 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) + + self.family = GenlFamily(self.yaml['name']) + + 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"] == 'u32': + attr_payload = struct.pack("I", 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._types[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'][i]) + raw >>= 1 + i += 1 + else: + value = enum['entries'][raw - i] + rsp[attr_spec['name']] = value + + 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'] == 'u32': + decoded = attr.as_u32() + elif attr_spec['type'] == 'u64': + decoded = attr.as_u64() + elif attr_spec["type"] == 'string': + decoded = attr.as_strz() + elif attr_spec["type"] == 'binary': + decoded = attr.as_bin() + 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 _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) + 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: + print("Netlink error:", os.strerror(-nl_msg.error)) + print(nl_msg) + return + if nl_msg.done: + if nl_msg.extack: + print("Netlink warning:") + print(nl_msg) + done = True + break + + gm = GenlMsg(nl_msg) + # 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.append(self._decode(gm.raw_attrs, op.attr_set.name)) + + 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) |