524 lines
17 KiB
Python
524 lines
17 KiB
Python
# SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
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import functools
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import os
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import random
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import socket
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import struct
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import yaml
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from .nlspec import SpecFamily
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#
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# Generic Netlink code which should really be in some library, but I can't quickly find one.
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#
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class Netlink:
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# Netlink socket
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SOL_NETLINK = 270
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NETLINK_ADD_MEMBERSHIP = 1
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NETLINK_CAP_ACK = 10
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NETLINK_EXT_ACK = 11
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# Netlink message
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NLMSG_ERROR = 2
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NLMSG_DONE = 3
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NLM_F_REQUEST = 1
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NLM_F_ACK = 4
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NLM_F_ROOT = 0x100
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NLM_F_MATCH = 0x200
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NLM_F_APPEND = 0x800
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NLM_F_CAPPED = 0x100
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NLM_F_ACK_TLVS = 0x200
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NLM_F_DUMP = NLM_F_ROOT | NLM_F_MATCH
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NLA_F_NESTED = 0x8000
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NLA_F_NET_BYTEORDER = 0x4000
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NLA_TYPE_MASK = NLA_F_NESTED | NLA_F_NET_BYTEORDER
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# Genetlink defines
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NETLINK_GENERIC = 16
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GENL_ID_CTRL = 0x10
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# nlctrl
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CTRL_CMD_GETFAMILY = 3
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CTRL_ATTR_FAMILY_ID = 1
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CTRL_ATTR_FAMILY_NAME = 2
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CTRL_ATTR_MAXATTR = 5
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CTRL_ATTR_MCAST_GROUPS = 7
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CTRL_ATTR_MCAST_GRP_NAME = 1
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CTRL_ATTR_MCAST_GRP_ID = 2
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# Extack types
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NLMSGERR_ATTR_MSG = 1
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NLMSGERR_ATTR_OFFS = 2
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NLMSGERR_ATTR_COOKIE = 3
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NLMSGERR_ATTR_POLICY = 4
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NLMSGERR_ATTR_MISS_TYPE = 5
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NLMSGERR_ATTR_MISS_NEST = 6
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class NlAttr:
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def __init__(self, raw, offset):
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self._len, self._type = struct.unpack("HH", raw[offset:offset + 4])
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self.type = self._type & ~Netlink.NLA_TYPE_MASK
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self.payload_len = self._len
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self.full_len = (self.payload_len + 3) & ~3
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self.raw = raw[offset + 4:offset + self.payload_len]
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def as_u8(self):
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return struct.unpack("B", self.raw)[0]
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def as_u16(self):
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return struct.unpack("H", self.raw)[0]
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def as_u32(self):
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return struct.unpack("I", self.raw)[0]
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def as_u64(self):
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return struct.unpack("Q", self.raw)[0]
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def as_strz(self):
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return self.raw.decode('ascii')[:-1]
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def as_bin(self):
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return self.raw
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def __repr__(self):
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return f"[type:{self.type} len:{self._len}] {self.raw}"
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class NlAttrs:
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def __init__(self, msg):
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self.attrs = []
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offset = 0
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while offset < len(msg):
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attr = NlAttr(msg, offset)
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offset += attr.full_len
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self.attrs.append(attr)
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def __iter__(self):
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yield from self.attrs
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def __repr__(self):
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msg = ''
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for a in self.attrs:
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if msg:
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msg += '\n'
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msg += repr(a)
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return msg
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class NlMsg:
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def __init__(self, msg, offset, attr_space=None):
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self.hdr = msg[offset:offset + 16]
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self.nl_len, self.nl_type, self.nl_flags, self.nl_seq, self.nl_portid = \
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struct.unpack("IHHII", self.hdr)
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self.raw = msg[offset + 16:offset + self.nl_len]
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self.error = 0
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self.done = 0
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extack_off = None
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if self.nl_type == Netlink.NLMSG_ERROR:
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self.error = struct.unpack("i", self.raw[0:4])[0]
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self.done = 1
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extack_off = 20
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elif self.nl_type == Netlink.NLMSG_DONE:
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self.done = 1
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extack_off = 4
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self.extack = None
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if self.nl_flags & Netlink.NLM_F_ACK_TLVS and extack_off:
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self.extack = dict()
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extack_attrs = NlAttrs(self.raw[extack_off:])
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for extack in extack_attrs:
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if extack.type == Netlink.NLMSGERR_ATTR_MSG:
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self.extack['msg'] = extack.as_strz()
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elif extack.type == Netlink.NLMSGERR_ATTR_MISS_TYPE:
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self.extack['miss-type'] = extack.as_u32()
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elif extack.type == Netlink.NLMSGERR_ATTR_MISS_NEST:
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self.extack['miss-nest'] = extack.as_u32()
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elif extack.type == Netlink.NLMSGERR_ATTR_OFFS:
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self.extack['bad-attr-offs'] = extack.as_u32()
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else:
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if 'unknown' not in self.extack:
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self.extack['unknown'] = []
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self.extack['unknown'].append(extack)
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if attr_space:
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# We don't have the ability to parse nests yet, so only do global
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if 'miss-type' in self.extack and 'miss-nest' not in self.extack:
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miss_type = self.extack['miss-type']
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if miss_type in attr_space.attrs_by_val:
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spec = attr_space.attrs_by_val[miss_type]
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desc = spec['name']
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if 'doc' in spec:
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desc += f" ({spec['doc']})"
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self.extack['miss-type'] = desc
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def __repr__(self):
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msg = f"nl_len = {self.nl_len} ({len(self.raw)}) nl_flags = 0x{self.nl_flags:x} nl_type = {self.nl_type}\n"
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if self.error:
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msg += '\terror: ' + str(self.error)
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if self.extack:
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msg += '\textack: ' + repr(self.extack)
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return msg
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class NlMsgs:
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def __init__(self, data, attr_space=None):
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self.msgs = []
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offset = 0
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while offset < len(data):
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msg = NlMsg(data, offset, attr_space=attr_space)
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offset += msg.nl_len
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self.msgs.append(msg)
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def __iter__(self):
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yield from self.msgs
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genl_family_name_to_id = None
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def _genl_msg(nl_type, nl_flags, genl_cmd, genl_version, seq=None):
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# we prepend length in _genl_msg_finalize()
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if seq is None:
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seq = random.randint(1, 1024)
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nlmsg = struct.pack("HHII", nl_type, nl_flags, seq, 0)
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genlmsg = struct.pack("BBH", genl_cmd, genl_version, 0)
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return nlmsg + genlmsg
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def _genl_msg_finalize(msg):
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return struct.pack("I", len(msg) + 4) + msg
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def _genl_load_families():
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with socket.socket(socket.AF_NETLINK, socket.SOCK_RAW, Netlink.NETLINK_GENERIC) as sock:
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sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_CAP_ACK, 1)
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msg = _genl_msg(Netlink.GENL_ID_CTRL,
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Netlink.NLM_F_REQUEST | Netlink.NLM_F_ACK | Netlink.NLM_F_DUMP,
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Netlink.CTRL_CMD_GETFAMILY, 1)
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msg = _genl_msg_finalize(msg)
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sock.send(msg, 0)
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global genl_family_name_to_id
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genl_family_name_to_id = dict()
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while True:
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reply = sock.recv(128 * 1024)
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nms = NlMsgs(reply)
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for nl_msg in nms:
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if nl_msg.error:
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print("Netlink error:", nl_msg.error)
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return
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if nl_msg.done:
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return
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gm = GenlMsg(nl_msg)
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fam = dict()
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for attr in gm.raw_attrs:
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if attr.type == Netlink.CTRL_ATTR_FAMILY_ID:
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fam['id'] = attr.as_u16()
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elif attr.type == Netlink.CTRL_ATTR_FAMILY_NAME:
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fam['name'] = attr.as_strz()
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elif attr.type == Netlink.CTRL_ATTR_MAXATTR:
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fam['maxattr'] = attr.as_u32()
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elif attr.type == Netlink.CTRL_ATTR_MCAST_GROUPS:
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fam['mcast'] = dict()
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for entry in NlAttrs(attr.raw):
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mcast_name = None
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mcast_id = None
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for entry_attr in NlAttrs(entry.raw):
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if entry_attr.type == Netlink.CTRL_ATTR_MCAST_GRP_NAME:
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mcast_name = entry_attr.as_strz()
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elif entry_attr.type == Netlink.CTRL_ATTR_MCAST_GRP_ID:
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mcast_id = entry_attr.as_u32()
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if mcast_name and mcast_id is not None:
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fam['mcast'][mcast_name] = mcast_id
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if 'name' in fam and 'id' in fam:
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genl_family_name_to_id[fam['name']] = fam
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class GenlMsg:
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def __init__(self, nl_msg):
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self.nl = nl_msg
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self.hdr = nl_msg.raw[0:4]
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self.raw = nl_msg.raw[4:]
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self.genl_cmd, self.genl_version, _ = struct.unpack("BBH", self.hdr)
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self.raw_attrs = NlAttrs(self.raw)
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def __repr__(self):
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msg = repr(self.nl)
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msg += f"\tgenl_cmd = {self.genl_cmd} genl_ver = {self.genl_version}\n"
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for a in self.raw_attrs:
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msg += '\t\t' + repr(a) + '\n'
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return msg
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class GenlFamily:
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def __init__(self, family_name):
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self.family_name = family_name
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global genl_family_name_to_id
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if genl_family_name_to_id is None:
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_genl_load_families()
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self.genl_family = genl_family_name_to_id[family_name]
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self.family_id = genl_family_name_to_id[family_name]['id']
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#
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# YNL implementation details.
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#
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class YnlFamily(SpecFamily):
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def __init__(self, def_path, schema=None):
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super().__init__(def_path, schema)
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self.include_raw = False
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self.sock = socket.socket(socket.AF_NETLINK, socket.SOCK_RAW, Netlink.NETLINK_GENERIC)
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self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_CAP_ACK, 1)
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self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_EXT_ACK, 1)
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self.async_msg_ids = set()
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self.async_msg_queue = []
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for msg in self.msgs.values():
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if msg.is_async:
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self.async_msg_ids.add(msg.rsp_value)
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for op_name, op in self.ops.items():
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bound_f = functools.partial(self._op, op_name)
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setattr(self, op.ident_name, bound_f)
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self.family = GenlFamily(self.yaml['name'])
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def ntf_subscribe(self, mcast_name):
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if mcast_name not in self.family.genl_family['mcast']:
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raise Exception(f'Multicast group "{mcast_name}" not present in the family')
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self.sock.bind((0, 0))
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self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_ADD_MEMBERSHIP,
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self.family.genl_family['mcast'][mcast_name])
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def _add_attr(self, space, name, value):
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attr = self.attr_sets[space][name]
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nl_type = attr.value
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if attr["type"] == 'nest':
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nl_type |= Netlink.NLA_F_NESTED
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attr_payload = b''
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for subname, subvalue in value.items():
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attr_payload += self._add_attr(attr['nested-attributes'], subname, subvalue)
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elif attr["type"] == 'flag':
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attr_payload = b''
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elif attr["type"] == 'u32':
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attr_payload = struct.pack("I", int(value))
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elif attr["type"] == 'string':
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attr_payload = str(value).encode('ascii') + b'\x00'
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elif attr["type"] == 'binary':
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attr_payload = value
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else:
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raise Exception(f'Unknown type at {space} {name} {value} {attr["type"]}')
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pad = b'\x00' * ((4 - len(attr_payload) % 4) % 4)
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return struct.pack('HH', len(attr_payload) + 4, nl_type) + attr_payload + pad
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def _decode_enum(self, rsp, attr_spec):
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raw = rsp[attr_spec['name']]
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enum = self.consts[attr_spec['enum']]
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i = attr_spec.get('value-start', 0)
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if 'enum-as-flags' in attr_spec and attr_spec['enum-as-flags']:
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value = set()
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while raw:
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if raw & 1:
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value.add(enum.entries_by_val[i].name)
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raw >>= 1
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i += 1
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else:
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value = enum.entries_by_val[raw - i].name
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rsp[attr_spec['name']] = value
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def _decode(self, attrs, space):
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attr_space = self.attr_sets[space]
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rsp = dict()
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for attr in attrs:
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attr_spec = attr_space.attrs_by_val[attr.type]
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if attr_spec["type"] == 'nest':
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subdict = self._decode(NlAttrs(attr.raw), attr_spec['nested-attributes'])
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decoded = subdict
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elif attr_spec['type'] == 'u8':
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decoded = attr.as_u8()
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elif attr_spec['type'] == 'u32':
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decoded = attr.as_u32()
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elif attr_spec['type'] == 'u64':
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decoded = attr.as_u64()
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elif attr_spec["type"] == 'string':
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decoded = attr.as_strz()
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elif attr_spec["type"] == 'binary':
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decoded = attr.as_bin()
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elif attr_spec["type"] == 'flag':
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decoded = True
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else:
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raise Exception(f'Unknown {attr.type} {attr_spec["name"]} {attr_spec["type"]}')
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if not attr_spec.is_multi:
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rsp[attr_spec['name']] = decoded
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elif attr_spec.name in rsp:
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rsp[attr_spec.name].append(decoded)
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else:
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rsp[attr_spec.name] = [decoded]
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if 'enum' in attr_spec:
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self._decode_enum(rsp, attr_spec)
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return rsp
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def _decode_extack_path(self, attrs, attr_set, offset, target):
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for attr in attrs:
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attr_spec = attr_set.attrs_by_val[attr.type]
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if offset > target:
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break
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if offset == target:
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return '.' + attr_spec.name
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if offset + attr.full_len <= target:
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offset += attr.full_len
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continue
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if attr_spec['type'] != 'nest':
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raise Exception(f"Can't dive into {attr.type} ({attr_spec['name']}) for extack")
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offset += 4
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subpath = self._decode_extack_path(NlAttrs(attr.raw),
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self.attr_sets[attr_spec['nested-attributes']],
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offset, target)
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if subpath is None:
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return None
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return '.' + attr_spec.name + subpath
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return None
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def _decode_extack(self, request, attr_space, extack):
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if 'bad-attr-offs' not in extack:
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return
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genl_req = GenlMsg(NlMsg(request, 0, attr_space=attr_space))
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path = self._decode_extack_path(genl_req.raw_attrs, attr_space,
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20, extack['bad-attr-offs'])
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if path:
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del extack['bad-attr-offs']
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extack['bad-attr'] = path
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def handle_ntf(self, nl_msg, genl_msg):
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msg = dict()
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if self.include_raw:
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msg['nlmsg'] = nl_msg
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msg['genlmsg'] = genl_msg
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op = self.rsp_by_value[genl_msg.genl_cmd]
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msg['name'] = op['name']
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msg['msg'] = self._decode(genl_msg.raw_attrs, op.attr_set.name)
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self.async_msg_queue.append(msg)
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def check_ntf(self):
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while True:
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try:
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reply = self.sock.recv(128 * 1024, socket.MSG_DONTWAIT)
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except BlockingIOError:
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return
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nms = NlMsgs(reply)
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for nl_msg in nms:
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if nl_msg.error:
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print("Netlink error in ntf!?", os.strerror(-nl_msg.error))
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print(nl_msg)
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continue
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if nl_msg.done:
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print("Netlink done while checking for ntf!?")
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continue
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gm = GenlMsg(nl_msg)
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if gm.genl_cmd not in self.async_msg_ids:
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print("Unexpected msg id done while checking for ntf", gm)
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continue
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self.handle_ntf(nl_msg, gm)
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def _op(self, method, vals, dump=False):
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op = self.ops[method]
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nl_flags = Netlink.NLM_F_REQUEST | Netlink.NLM_F_ACK
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if dump:
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nl_flags |= Netlink.NLM_F_DUMP
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req_seq = random.randint(1024, 65535)
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msg = _genl_msg(self.family.family_id, nl_flags, op.req_value, 1, req_seq)
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for name, value in vals.items():
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msg += self._add_attr(op.attr_set.name, name, value)
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msg = _genl_msg_finalize(msg)
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self.sock.send(msg, 0)
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done = False
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rsp = []
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while not done:
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reply = self.sock.recv(128 * 1024)
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nms = NlMsgs(reply, attr_space=op.attr_set)
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for nl_msg in nms:
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if nl_msg.extack:
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self._decode_extack(msg, op.attr_set, nl_msg.extack)
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if nl_msg.error:
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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)
|