Commit f036d936 authored by Donald Hunter's avatar Donald Hunter Committed by Jakub Kicinski
Browse files

tools: ynl: Add fixed-header support to ynl 



Add support for netlink families that add an optional fixed header structure
after the genetlink header and before any attributes. The fixed-header can be
specified on a per op basis, or once for all operations, which serves as a
default value that can be overridden.

Signed-off-by: default avatarDonald Hunter <donald.hunter@gmail.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 26071913

Documentation/netlink/genetlink-legacy.yaml

+11 −0
Original line number Diff line number Diff line
@@ -261,6 +261,14 @@ properties: 
      async-enum:

        description: Name for the enum type with notifications/events.

        type: string

      # Start genetlink-legacy

      fixed-header: &fixed-header

        description: |

          Name of the structure defining the optional fixed-length protocol

          header. This header is placed in a message after the netlink and

          genetlink headers and before any attributes.

        type: string

      # End genetlink-legacy

      list:

        description: List of commands

        type: array
@@ -293,6 +301,9 @@ properties: 
              type: array

              items:

                enum: [ strict, dump ]

            # Start genetlink-legacy

            fixed-header: *fixed-header

            # End genetlink-legacy

            do: &subop-type

              description: Main command handler.

              type: object

tools/net/ynl/lib/nlspec.py

+13 −8
Original line number Diff line number Diff line
@@ -271,6 +271,7 @@ class SpecOperation(SpecElement): 
        is_async        bool, whether the operation is a notification

        is_resv         bool, whether the operation does not exist (it's just a reserved ID)

        attr_set        attribute set name

        fixed_header    string, optional name of fixed header struct



        yaml            raw spec as loaded from the spec file

    """
@@ -284,6 +285,7 @@ class SpecOperation(SpecElement): 
        self.is_call = 'do' in yaml or 'dump' in yaml

        self.is_async = 'notify' in yaml or 'event' in yaml

        self.is_resv = not self.is_async and not self.is_call

        self.fixed_header = self.yaml.get('fixed-header', family.fixed_header)



        # Added by resolve:

        self.attr_set = None
@@ -324,6 +326,7 @@ class SpecFamily(SpecElement): 
        msgs_by_value  dict of all messages (indexed by name)

        ops        dict of all valid requests / responses

        consts     dict of all constants/enums

        fixed_header  string, optional name of family default fixed header struct

    """

    def __init__(self, spec_path, schema_path=None):

        with open(spec_path, "r") as stream:
@@ -397,6 +400,7 @@ class SpecFamily(SpecElement): 
        self._resolution_list.append(elem)



    def _dictify_ops_unified(self):

        self.fixed_header = self.yaml['operations'].get('fixed-header')

        val = 1

        for elem in self.yaml['operations']['list']:

            if 'value' in elem:
@@ -408,6 +412,7 @@ class SpecFamily(SpecElement): 
            self.msgs[op.name] = op



    def _dictify_ops_directional(self):

        self.fixed_header = self.yaml['operations'].get('fixed-header')

        req_val = rsp_val = 1

        for elem in self.yaml['operations']['list']:

            if 'notify' in elem:

tools/net/ynl/lib/ynl.py

+20 −4
Original line number Diff line number Diff line
@@ -278,14 +278,22 @@ def _genl_load_families(): 




class GenlMsg:

    def __init__(self, nl_msg):

    def __init__(self, nl_msg, fixed_header_members=[]):

        self.nl = nl_msg



        self.hdr = nl_msg.raw[0:4]

        self.raw = nl_msg.raw[4:]

        offset = 4



        self.genl_cmd, self.genl_version, _ = struct.unpack("BBH", self.hdr)



        self.fixed_header_attrs = dict()

        for m in fixed_header_members:

            format, size = NlAttr.type_formats[m.type]

            decoded = struct.unpack_from(format, nl_msg.raw, offset)

            offset += size

            self.fixed_header_attrs[m.name] = decoded[0]



        self.raw = nl_msg.raw[offset:]

        self.raw_attrs = NlAttrs(self.raw)



    def __repr__(self):
@@ -509,6 +517,13 @@ class YnlFamily(SpecFamily): 


        req_seq = random.randint(1024, 65535)

        msg = _genl_msg(self.family.family_id, nl_flags, op.req_value, 1, req_seq)

        fixed_header_members = []

        if op.fixed_header:

            fixed_header_members = self.consts[op.fixed_header].members

            for m in fixed_header_members:

                value = vals.pop(m.name)

                format, _ = NlAttr.type_formats[m.type]

                msg += struct.pack(format, value)

        for name, value in vals.items():

            msg += self._add_attr(op.attr_set.name, name, value)

        msg = _genl_msg_finalize(msg)
@@ -535,7 +550,7 @@ class YnlFamily(SpecFamily): 
                    done = True

                    break



                gm = GenlMsg(nl_msg)

                gm = GenlMsg(nl_msg, fixed_header_members)

                # 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:
@@ -545,7 +560,8 @@ class YnlFamily(SpecFamily): 
                        print('Unexpected message: ' + repr(gm))

                        continue



                rsp.append(self._decode(gm.raw_attrs, op.attr_set.name))

                rsp.append(self._decode(gm.raw_attrs, op.attr_set.name)

                           | gm.fixed_header_attrs)



        if not rsp:

            return None