b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame^] | 1 | # |
| 2 | # (Generic) Netlink message generation/parsing |
| 3 | # Copyright (c) 2007 Johannes Berg <johannes@sipsolutions.net> |
| 4 | # Copyright (c) 2014 Intel Corporation |
| 5 | # |
| 6 | # This software may be distributed under the terms of the BSD license. |
| 7 | # See README for more details. |
| 8 | |
| 9 | import struct, socket |
| 10 | |
| 11 | # flags |
| 12 | NLM_F_REQUEST = 1 |
| 13 | NLM_F_MULTI = 2 |
| 14 | NLM_F_ACK = 4 |
| 15 | NLM_F_ECHO = 8 |
| 16 | |
| 17 | # types |
| 18 | NLMSG_NOOP = 1 |
| 19 | NLMSG_ERROR = 2 |
| 20 | NLMSG_DONE = 3 |
| 21 | NLMSG_OVERRUN = 4 |
| 22 | NLMSG_MIN_TYPE = 0x10 |
| 23 | |
| 24 | class Attr(object): |
| 25 | def __init__(self, attr_type, data, *values): |
| 26 | self._type = attr_type |
| 27 | if len(values): |
| 28 | self._data = struct.pack(data, *values) |
| 29 | else: |
| 30 | self._data = data |
| 31 | |
| 32 | def _dump(self): |
| 33 | hdr = struct.pack("HH", len(self._data) + 4, self._type) |
| 34 | length = len(self._data) |
| 35 | pad = ((length + 4 - 1) & ~3) - length |
| 36 | return hdr + self._data + b'\x00' * pad |
| 37 | |
| 38 | def __repr__(self): |
| 39 | return '<Attr type %d, data "%s">' % (self._type, repr(self._data)) |
| 40 | |
| 41 | def u16(self): |
| 42 | return struct.unpack('H', self._data)[0] |
| 43 | def s16(self): |
| 44 | return struct.unpack('h', self._data)[0] |
| 45 | def u32(self): |
| 46 | return struct.unpack('I', self._data)[0] |
| 47 | def s32(self): |
| 48 | return struct.unpack('i', self._data)[0] |
| 49 | def str(self): |
| 50 | return self._data |
| 51 | def nulstr(self): |
| 52 | return self._data.split('\0')[0] |
| 53 | def nested(self): |
| 54 | return parse_attributes(self._data) |
| 55 | |
| 56 | class StrAttr(Attr): |
| 57 | def __init__(self, attr_type, data): |
| 58 | Attr.__init__(self, attr_type, "%ds" % len(data), data) |
| 59 | |
| 60 | class NulStrAttr(Attr): |
| 61 | def __init__(self, attr_type, data): |
| 62 | Attr.__init__(self, attr_type, "%dsB" % len(data), data, 0) |
| 63 | |
| 64 | class U32Attr(Attr): |
| 65 | def __init__(self, attr_type, val): |
| 66 | Attr.__init__(self, attr_type, "I", val) |
| 67 | |
| 68 | class U8Attr(Attr): |
| 69 | def __init__(self, attr_type, val): |
| 70 | Attr.__init__(self, attr_type, "B", val) |
| 71 | |
| 72 | class FlagAttr(Attr): |
| 73 | def __init__(self, attr_type): |
| 74 | Attr.__init__(self, attr_type, b"") |
| 75 | |
| 76 | class Nested(Attr): |
| 77 | def __init__(self, attr_type, attrs): |
| 78 | self.attrs = attrs |
| 79 | self.type = attr_type |
| 80 | |
| 81 | def _dump(self): |
| 82 | contents = [] |
| 83 | for attr in self.attrs: |
| 84 | contents.append(attr._dump()) |
| 85 | contents = ''.join(contents) |
| 86 | length = len(contents) |
| 87 | hdr = struct.pack("HH", length+4, self.type) |
| 88 | return hdr + contents |
| 89 | |
| 90 | NETLINK_ROUTE = 0 |
| 91 | NETLINK_UNUSED = 1 |
| 92 | NETLINK_USERSOCK = 2 |
| 93 | NETLINK_FIREWALL = 3 |
| 94 | NETLINK_INET_DIAG = 4 |
| 95 | NETLINK_NFLOG = 5 |
| 96 | NETLINK_XFRM = 6 |
| 97 | NETLINK_SELINUX = 7 |
| 98 | NETLINK_ISCSI = 8 |
| 99 | NETLINK_AUDIT = 9 |
| 100 | NETLINK_FIB_LOOKUP = 10 |
| 101 | NETLINK_CONNECTOR = 11 |
| 102 | NETLINK_NETFILTER = 12 |
| 103 | NETLINK_IP6_FW = 13 |
| 104 | NETLINK_DNRTMSG = 14 |
| 105 | NETLINK_KOBJECT_UEVENT = 15 |
| 106 | NETLINK_GENERIC = 16 |
| 107 | |
| 108 | class Message(object): |
| 109 | def __init__(self, msg_type, flags=0, seq=-1, payload=None): |
| 110 | self.type = msg_type |
| 111 | self.flags = flags |
| 112 | self.seq = seq |
| 113 | self.pid = -1 |
| 114 | payload = payload or [] |
| 115 | if isinstance(payload, list): |
| 116 | self.payload = bytes() |
| 117 | for attr in payload: |
| 118 | self.payload += attr._dump() |
| 119 | else: |
| 120 | self.payload = payload |
| 121 | |
| 122 | def send(self, conn): |
| 123 | if self.seq == -1: |
| 124 | self.seq = conn.seq() |
| 125 | |
| 126 | self.pid = conn.pid |
| 127 | length = len(self.payload) |
| 128 | |
| 129 | hdr = struct.pack("IHHII", length + 4*4, self.type, |
| 130 | self.flags, self.seq, self.pid) |
| 131 | conn.send(hdr + self.payload) |
| 132 | |
| 133 | def __repr__(self): |
| 134 | return '<netlink.Message type=%d, pid=%d, seq=%d, flags=0x%x "%s">' % ( |
| 135 | self.type, self.pid, self.seq, self.flags, repr(self.payload)) |
| 136 | |
| 137 | @property |
| 138 | def ret(self): |
| 139 | assert self.type == NLMSG_ERROR |
| 140 | return struct.unpack("i", self.payload[:4])[0] |
| 141 | |
| 142 | def send_and_recv(self, conn): |
| 143 | self.send(conn) |
| 144 | while True: |
| 145 | m = conn.recv() |
| 146 | if m.seq == self.seq: |
| 147 | return m |
| 148 | |
| 149 | class Connection(object): |
| 150 | def __init__(self, nltype, groups=0, unexpected_msg_handler=None): |
| 151 | self.descriptor = socket.socket(socket.AF_NETLINK, |
| 152 | socket.SOCK_RAW, nltype) |
| 153 | self.descriptor.setsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF, 65536) |
| 154 | self.descriptor.setsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF, 65536) |
| 155 | self.descriptor.bind((0, groups)) |
| 156 | self.pid, self.groups = self.descriptor.getsockname() |
| 157 | self._seq = 0 |
| 158 | self.unexpected = unexpected_msg_handler |
| 159 | def send(self, msg): |
| 160 | self.descriptor.send(msg) |
| 161 | def recv(self): |
| 162 | contents = self.descriptor.recv(16384) |
| 163 | # XXX: python doesn't give us message flags, check |
| 164 | # len(contents) vs. msglen for TRUNC |
| 165 | msglen, msg_type, flags, seq, pid = struct.unpack("IHHII", |
| 166 | contents[:16]) |
| 167 | msg = Message(msg_type, flags, seq, contents[16:]) |
| 168 | msg.pid = pid |
| 169 | if msg.type == NLMSG_ERROR: |
| 170 | import os |
| 171 | errno = msg.ret |
| 172 | if errno < 0: |
| 173 | err = OSError("Netlink error: %s (%d)" % ( |
| 174 | os.strerror(-errno), -errno)) |
| 175 | err.errno = -errno |
| 176 | raise err |
| 177 | return msg |
| 178 | def seq(self): |
| 179 | self._seq += 1 |
| 180 | return self._seq |
| 181 | |
| 182 | def parse_attributes(data): |
| 183 | attrs = {} |
| 184 | while len(data): |
| 185 | attr_len, attr_type = struct.unpack("HH", data[:4]) |
| 186 | attrs[attr_type] = Attr(attr_type, data[4:attr_len]) |
| 187 | attr_len = ((attr_len + 4 - 1) & ~3) |
| 188 | data = data[attr_len:] |
| 189 | return attrs |
| 190 | |
| 191 | |
| 192 | |
| 193 | CTRL_CMD_UNSPEC = 0 |
| 194 | CTRL_CMD_NEWFAMILY = 1 |
| 195 | CTRL_CMD_DELFAMILY = 2 |
| 196 | CTRL_CMD_GETFAMILY = 3 |
| 197 | CTRL_CMD_NEWOPS = 4 |
| 198 | CTRL_CMD_DELOPS = 5 |
| 199 | CTRL_CMD_GETOPS = 6 |
| 200 | |
| 201 | CTRL_ATTR_UNSPEC = 0 |
| 202 | CTRL_ATTR_FAMILY_ID = 1 |
| 203 | CTRL_ATTR_FAMILY_NAME = 2 |
| 204 | CTRL_ATTR_VERSION = 3 |
| 205 | CTRL_ATTR_HDRSIZE = 4 |
| 206 | CTRL_ATTR_MAXATTR = 5 |
| 207 | CTRL_ATTR_OPS = 6 |
| 208 | |
| 209 | class GenlHdr(object): |
| 210 | def __init__(self, cmd, version=0): |
| 211 | self.cmd = cmd |
| 212 | self.version = version |
| 213 | def _dump(self): |
| 214 | return struct.pack("BBxx", self.cmd, self.version) |
| 215 | |
| 216 | def _genl_hdr_parse(data): |
| 217 | return GenlHdr(*struct.unpack("BBxx", data)) |
| 218 | |
| 219 | GENL_ID_CTRL = NLMSG_MIN_TYPE |
| 220 | |
| 221 | class GenlMessage(Message): |
| 222 | def __init__(self, family, cmd, attrs=[], flags=0): |
| 223 | Message.__init__(self, family, flags=flags, payload=[GenlHdr(cmd)] + attrs) |
| 224 | |
| 225 | class GenlController(object): |
| 226 | def __init__(self, conn): |
| 227 | self.conn = conn |
| 228 | def get_family_id(self, family): |
| 229 | a = NulStrAttr(CTRL_ATTR_FAMILY_NAME, family) |
| 230 | m = GenlMessage(GENL_ID_CTRL, CTRL_CMD_GETFAMILY, flags=NLM_F_REQUEST, attrs=[a]) |
| 231 | m.send(self.conn) |
| 232 | m = self.conn.recv() |
| 233 | gh = _genl_hdr_parse(m.payload[:4]) |
| 234 | attrs = parse_attributes(m.payload[4:]) |
| 235 | return attrs[CTRL_ATTR_FAMILY_ID].u16() |
| 236 | |
| 237 | genl_controller = GenlController(Connection(NETLINK_GENERIC)) |