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Message-Id: <20220811022304.583300-4-kuba@kernel.org>
Date: Wed, 10 Aug 2022 19:23:03 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: netdev@...r.kernel.org, davem@...emloft.net, edumazet@...gle.com,
pabeni@...hat.com
Cc: sdf@...gle.com, jacob.e.keller@...el.com, vadfed@...com,
johannes@...solutions.net, jiri@...nulli.us, dsahern@...nel.org,
stephen@...workplumber.org, fw@...len.de,
linux-doc@...r.kernel.org, Jakub Kicinski <kuba@...nel.org>
Subject: [RFC net-next 3/4] ynl: add a sample python library
A very short and very incomplete generic python library.
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
---
tools/net/ynl/samples/ynl.py | 342 +++++++++++++++++++++++++++++++++++
1 file changed, 342 insertions(+)
create mode 100644 tools/net/ynl/samples/ynl.py
diff --git a/tools/net/ynl/samples/ynl.py b/tools/net/ynl/samples/ynl.py
new file mode 100644
index 000000000000..59c178e063f1
--- /dev/null
+++ b/tools/net/ynl/samples/ynl.py
@@ -0,0 +1,342 @@
+# SPDX-License-Identifier: BSD-3-Clause
+
+import functools
+import jsonschema
+import random
+import socket
+import struct
+import yaml
+
+#
+# Generic Netlink code which should really be in some library, but I can't quickly find one.
+#
+
+
+class Netlink:
+ SOL_NETLINK = 270
+
+ NETLINK_CAP_ACK = 10
+
+ 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_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
+
+
+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_u16(self):
+ return struct.unpack("H", self.raw)[0]
+
+ def as_u32(self):
+ return struct.unpack("I", self.raw)[0]
+
+ def as_strz(self):
+ return self.raw.decode('ascii')[:-1]
+
+ 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
+
+
+class NlMsg:
+ def __init__(self, msg, offset):
+ 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
+
+ if self.nl_type == Netlink.NLMSG_ERROR:
+ self.error = struct.unpack("i", self.raw[0:4])[0]
+ self.done = 1
+ elif self.nl_type == Netlink.NLMSG_DONE:
+ self.done = 1
+
+ def __repr__(self):
+ msg = f"nl_len = {self.nl_len} nl_flags = 0x{self.nl_flags:x} nl_type = {self.nl_type}\n"
+ if self.error:
+ msg += '\terror: ' + str(self.error)
+ return msg
+
+
+class NlMsgs:
+ def __init__(self, data):
+ self.msgs = []
+
+ offset = 0
+ while offset < len(data):
+ msg = NlMsg(data, offset)
+ 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):
+ # we prepend length in _genl_msg_finalize()
+ nlmsg = struct.pack("HHII", nl_type, nl_flags, random.randint(1, 1024), 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_id = None
+ fam_name = None
+ 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()
+ if fam_id is not None and fam_name is not None:
+ genl_family_name_to_id[fam_name] = fam_id
+
+
+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.family_id = genl_family_name_to_id[family_name]
+
+#
+# YNL implementation details.
+#
+
+
+class YnlAttrSpace:
+ def __init__(self, family, yaml):
+ self.yaml = yaml
+
+ self.attrs = dict()
+ self.name = self.yaml['name']
+ self.name_prefix = self.yaml['name-prefix']
+ self.subspace_of = self.yaml['subspace-of'] if 'subspace-of' in self.yaml else None
+
+ val = 0
+ max_val = 0
+ for elem in self.yaml['attributes']:
+ if 'val' in elem:
+ val = elem['val']
+ else:
+ elem['val'] = val
+ if val > max_val:
+ max_val = val
+ val += 1
+
+ self.attrs[elem['name']] = elem
+
+ self.attr_list = [None] * (max_val + 1)
+ for elem in self.yaml['attributes']:
+ self.attr_list[elem['val']] = elem
+
+ def __getitem__(self, key):
+ return self.attrs[key]
+
+ def __contains__(self, key):
+ return key in self.yaml
+
+ def __iter__(self):
+ yield from self.attrs
+
+ def items(self):
+ return self.attrs.items()
+
+
+class YnlFamily:
+ def __init__(self, def_path, schema=None):
+ with open(def_path, "r") as stream:
+ self.yaml = yaml.safe_load(stream)
+
+ if schema:
+ with open(os.path.dirname(os.path.dirname(file_name)) + '/schema.yaml', "r") as stream:
+ schema = yaml.safe_load(stream)
+
+ jsonschema.validate(self.yaml, schema)
+
+ 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._ops = dict()
+ self._spaces = dict()
+
+ for elem in self.yaml['attribute-spaces']:
+ self._spaces[elem['name']] = YnlAttrSpace(self, elem)
+
+ async_separation = 'async-prefix' in self.yaml['operations']
+ val = 0
+ for elem in self.yaml['operations']['list']:
+ if not (async_separation and ('notify' in elem or 'event' in elem)):
+ if 'val' in elem:
+ val = elem['val']
+ else:
+ elem['val'] = val
+ val += 1
+
+ self._ops[elem['name']] = elem
+
+ bound_f = functools.partial(self._op, elem['name'])
+ setattr(self, elem['name'], bound_f)
+
+ self.family = GenlFamily(self.yaml['name'])
+
+ def _add_attr(self, space, name, value):
+ attr = self._spaces[space][name]
+ nl_type = attr['val']
+ 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"] == 'u32':
+ attr_payload = struct.pack("I", int(value))
+ elif attr["type"] == 'nul-string':
+ attr_payload = str(value).encode('ascii') + b'\x00'
+ 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(self, attrs, space):
+ attr_space = self._spaces[space]
+ rsp = dict()
+ for attr in attrs:
+ attr_spec = attr_space.attr_list[attr.type]
+ if attr_spec["type"] == 'nest':
+ subdict = self._decode(NlAttrs(attr.raw), attr_spec['nested-attributes'])
+ rsp[attr_spec['name']] = subdict
+ elif attr_spec['type'] == 'u32':
+ rsp[attr_spec['name']] = attr.as_u32()
+ elif attr_spec["type"] == 'nul-string':
+ rsp[attr_spec['name']] = attr.as_strz()
+ else:
+ raise Exception(f'Unknown {attr.type} {attr_spec["name"]} {attr_spec["type"]}')
+ return rsp
+
+ def _op(self, method, vals):
+ op = self._ops[method]
+
+ msg = _genl_msg(self.family.family_id, Netlink.NLM_F_REQUEST | Netlink.NLM_F_ACK,
+ op['val'], 1)
+ for name, value in vals.items():
+ msg += self._add_attr(op['attribute-space'], name, value)
+ msg = _genl_msg_finalize(msg)
+
+ self.sock.send(msg, 0)
+
+ done = False
+ rsp = None
+ while not done:
+ reply = self.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:
+ done = True
+ break
+
+ gm = GenlMsg(nl_msg)
+ rsp = self._decode(gm.raw_attrs, op['attribute-space'])
+
+ return rsp
--
2.37.1
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