Merge branch 'tools-net-ynl-add-sub-message-support-to-ynl'

Donald Hunter says:

====================
tools/net/ynl: Add 'sub-message' support to ynl

This patchset adds a 'sub-message' attribute type to the netlink-raw
schema and implements it in ynl. This provides support for kind-specific
options attributes as used in rt_link and tc raw netlink families.

A description of the new 'sub-message' attribute type and the
corresponding sub-message definitions is provided in patch 3.

The patchset includes updates to the rt_link spec and a new tc spec that
make use of the new 'sub-message' attribute type.

As mentioned in patch 4, encode support is not yet implemented in ynl
and support for sub-message selectors at a different nest level from the
key attribute is not yet supported. I plan to work on these in follow-up
patches.

Patches 1 is code cleanup in ynl
Patches 2-4 add sub-message support to the schema and ynl with
documentation updates.
Patch 5 adds binary and pad support to structs in netlink-raw.
Patches 6-8 contain specs that use the sub-message attribute type.
Patches 9-13 update ynl-gen-rst and its make target
====================

Link: https://lore.kernel.org/r/20231215093720.18774-1-donald.hunter@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 55 insertions, 0 deletions

diff --git a/tools/net/ynl/lib/nlspec.py b/tools/net/ynl/lib/nlspec.py
index 92889298b197..44f13e383e8a 100644
--- a/tools/net/ynl/lib/nlspec.py
+++ b/tools/net/ynl/lib/nlspec.py
@@ -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':