Commit 4cd2796f authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

tools: ynl: support pretty printing bad attribute names 



One of my favorite features of the Netlink specs is that they
make decoding structured extack a ton easier.
Implement pretty printing bad attribute names in YNL.

For example it will now say:

  'bad-attr': '.header.flags'

rather than the useless:

  'bad-attr-offs': 32

Proof:

  $ ./cli.py --spec ethtool.yaml --do rings_get \
     --json '{"header":{"dev-index":1, "flags":4}}'
  Netlink error: Invalid argument
  nl_len = 68 (52) nl_flags = 0x300 nl_type = 2
	error: -22	extack: {'msg': 'reserved bit set',
				 'bad-attr': '.header.flags'}

Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 90256f3f

tools/net/ynl/lib/ynl.py

+40 −0
Original line number Diff line number Diff line
@@ -400,6 +400,40 @@ class YnlFamily(SpecFamily): 
                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:
@@ -455,11 +489,17 @@ class YnlFamily(SpecFamily): 
            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