Commit 1769e2be authored by Donald Hunter's avatar Donald Hunter Committed by Jakub Kicinski
Browse files

tools/net/ynl: Add 'sub-message' attribute decoding to ynl 



Implement the 'sub-message' attribute type in ynl.

Encode support is not yet implemented. Support for sub-message selectors
at a different nest level from the key attribute is not yet supported.

Reviewed-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarDonald Hunter <donald.hunter@gmail.com>
Link: https://lore.kernel.org/r/20231215093720.18774-5-donald.hunter@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 17ed5c1a

tools/net/ynl/lib/nlspec.py

+55 −0
Original line number Diff line number Diff line
@@ -158,6 +158,9 @@ class SpecAttr(SpecElement): 
        len           integer, optional byte length of binary types

        display_hint  string, hint to help choose format specifier

                      when displaying the value

        sub_message   string, name of sub message type

        selector      string, name of attribute used to select

                      sub-message type



        is_auto_scalar bool, attr is a variable-size scalar

    """
@@ -173,6 +176,8 @@ class SpecAttr(SpecElement): 
        self.byte_order = yaml.get('byte-order')

        self.len = yaml.get('len')

        self.display_hint = yaml.get('display-hint')

        self.sub_message = yaml.get('sub-message')

        self.selector = yaml.get('selector')



        self.is_auto_scalar = self.type == "sint" or self.type == "uint"
@@ -278,6 +283,47 @@ class SpecStruct(SpecElement): 
        return self.members.items()





class SpecSubMessage(SpecElement):

    """ Netlink sub-message definition



    Represents a set of sub-message formats for polymorphic nlattrs

    that contain type-specific sub messages.



    Attributes:

        name     string, name of sub-message definition

        formats  dict of sub-message formats indexed by match value

    """

    def __init__(self, family, yaml):

        super().__init__(family, yaml)



        self.formats = collections.OrderedDict()

        for elem in self.yaml['formats']:

            format = self.new_format(family, elem)

            self.formats[format.value] = format



    def new_format(self, family, format):

        return SpecSubMessageFormat(family, format)





class SpecSubMessageFormat(SpecElement):

    """ Netlink sub-message definition



    Represents a set of sub-message formats for polymorphic nlattrs

    that contain type-specific sub messages.



    Attributes:

        value         attribute value to match against type selector

        fixed_header  string, name of fixed header, or None

        attr_set      string, name of attribute set, or None

    """

    def __init__(self, family, yaml):

        super().__init__(family, yaml)



        self.value = yaml.get('value')

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

        self.attr_set = yaml.get('attribute-set')





class SpecOperation(SpecElement):

    """Netlink Operation
@@ -365,6 +411,7 @@ class SpecFamily(SpecElement): 


        attr_sets  dict of attribute sets

        msgs       dict of all messages (index by name)

        sub_msgs   dict of all sub messages (index by name)

        ops        dict of all valid requests / responses

        ntfs       dict of all async events

        consts     dict of all constants/enums
@@ -405,6 +452,7 @@ class SpecFamily(SpecElement): 
            jsonschema.validate(self.yaml, schema)



        self.attr_sets = collections.OrderedDict()

        self.sub_msgs = collections.OrderedDict()

        self.msgs = collections.OrderedDict()

        self.req_by_value = collections.OrderedDict()

        self.rsp_by_value = collections.OrderedDict()
@@ -441,6 +489,9 @@ class SpecFamily(SpecElement): 
    def new_struct(self, elem):

        return SpecStruct(self, elem)



    def new_sub_message(self, elem):

        return SpecSubMessage(self, elem);



    def new_operation(self, elem, req_val, rsp_val):

        return SpecOperation(self, elem, req_val, rsp_val)
@@ -529,6 +580,10 @@ class SpecFamily(SpecElement): 
            attr_set = self.new_attr_set(elem)

            self.attr_sets[elem['name']] = attr_set



        for elem in self.yaml.get('sub-messages', []):

            sub_message = self.new_sub_message(elem)

            self.sub_msgs[sub_message.name] = sub_message



        if self.msg_id_model == 'unified':

            self._dictify_ops_unified()

        elif self.msg_id_model == 'directional':

tools/net/ynl/lib/ynl.py

+40 −8
Original line number Diff line number Diff line
@@ -170,10 +170,9 @@ class NlAttr: 




class NlAttrs:

    def __init__(self, msg):

    def __init__(self, msg, offset=0):

        self.attrs = []



        offset = 0

        while offset < len(msg):

            attr = NlAttr(msg, offset)

            offset += attr.full_len
@@ -371,8 +370,8 @@ class NetlinkProtocol: 
        fixed_header_size = 0

        if ynl:

            op = ynl.rsp_by_value[msg.cmd()]

            fixed_header_size = ynl._fixed_header_size(op)

        msg.raw_attrs = NlAttrs(msg.raw[fixed_header_size:])

            fixed_header_size = ynl._fixed_header_size(op.fixed_header)

        msg.raw_attrs = NlAttrs(msg.raw, fixed_header_size)

        return msg



    def get_mcast_id(self, mcast_name, mcast_groups):
@@ -549,6 +548,37 @@ class YnlFamily(SpecFamily): 
        else:

            rsp[name] = [decoded]



    def _resolve_selector(self, attr_spec, vals):

        sub_msg = attr_spec.sub_message

        if sub_msg not in self.sub_msgs:

            raise Exception(f"No sub-message spec named {sub_msg} for {attr_spec.name}")

        sub_msg_spec = self.sub_msgs[sub_msg]



        selector = attr_spec.selector

        if selector not in vals:

            raise Exception(f"There is no value for {selector} to resolve '{attr_spec.name}'")

        value = vals[selector]

        if value not in sub_msg_spec.formats:

            raise Exception(f"No message format for '{value}' in sub-message spec '{sub_msg}'")



        spec = sub_msg_spec.formats[value]

        return spec



    def _decode_sub_msg(self, attr, attr_spec, rsp):

        msg_format = self._resolve_selector(attr_spec, rsp)

        decoded = {}

        offset = 0

        if msg_format.fixed_header:

            decoded.update(self._decode_fixed_header(attr, msg_format.fixed_header));

            offset = self._fixed_header_size(msg_format.fixed_header)

        if msg_format.attr_set:

            if msg_format.attr_set in self.attr_sets:

                subdict = self._decode(NlAttrs(attr.raw, offset), msg_format.attr_set)

                decoded.update(subdict)

            else:

                raise Exception(f"Unknown attribute-set '{attr_space}' when decoding '{attr_spec.name}'")

        return decoded



    def _decode(self, attrs, space):

        if space:

            attr_space = self.attr_sets[space]
@@ -586,6 +616,8 @@ class YnlFamily(SpecFamily): 
                    value = self._decode_enum(value, attr_spec)

                    selector = self._decode_enum(selector, attr_spec)

                decoded = {"value": value, "selector": selector}

            elif attr_spec["type"] == 'sub-message':

                decoded = self._decode_sub_msg(attr, attr_spec, rsp)

            else:

                if not self.process_unknown:

                    raise Exception(f'Unknown {attr_spec["type"]} with name {attr_spec["name"]}')
@@ -626,16 +658,16 @@ class YnlFamily(SpecFamily): 
            return



        msg = self.nlproto.decode(self, NlMsg(request, 0, op.attr_set))

        offset = 20 + self._fixed_header_size(op)

        offset = 20 + self._fixed_header_size(op.fixed_header)

        path = self._decode_extack_path(msg.raw_attrs, op.attr_set, offset,

                                        extack['bad-attr-offs'])

        if path:

            del extack['bad-attr-offs']

            extack['bad-attr'] = path



    def _fixed_header_size(self, op):

        if op.fixed_header:

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

    def _fixed_header_size(self, name):

        if name:

            fixed_header_members = self.consts[name].members

            size = 0

            for m in fixed_header_members:

                format = NlAttr.get_format(m.type, m.byte_order)