tools/ynl: Add mcast-group schema parsing to ynl

Add a SpecMcastGroup class to the nlspec lib.

Signed-off-by: Donald Hunter <donald.hunter@gmail.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://lore.kernel.org/r/20230825122756.7603-6-donald.hunter@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: donaldh

tools/net/ynl/lib/nlspec.py

@@ -322,6 +322,26 @@ def resolve(self):
             self.attr_set = self.family.attr_sets[attr_set_name]
 
 
+class SpecMcastGroup(SpecElement):
+    """Netlink Multicast Group
+
+    Information about a multicast group.
+
+    Value is only used for classic netlink families that use the
+    netlink-raw schema. Genetlink families use dynamic ID allocation
+    where the ids of multicast groups get resolved at runtime. Value
+    will be None for genetlink families.
+
+    Attributes:
+        name      name of the mulitcast group
+        value     integer id of this multicast group for netlink-raw or None
+        yaml      raw spec as loaded from the spec file
+    """
+    def __init__(self, family, yaml):
+        super().__init__(family, yaml)
+        self.value = self.yaml.get('value')
+
+
 class SpecFamily(SpecElement):
     """ Netlink Family Spec class.
 
@@ -343,6 +363,7 @@ class SpecFamily(SpecElement):
         ntfs       dict of all async events
         consts     dict of all constants/enums
         fixed_header  string, optional name of family default fixed header struct
+        mcast_groups  dict of all multicast groups (index by name)
     """
     def __init__(self, spec_path, schema_path=None, exclude_ops=None):
         with open(spec_path, "r") as stream:
@@ -384,6 +405,7 @@ def __init__(self, spec_path, schema_path=None, exclude_ops=None):
         self.ops = collections.OrderedDict()
         self.ntfs = collections.OrderedDict()
         self.consts = collections.OrderedDict()
+        self.mcast_groups = collections.OrderedDict()
 
         last_exception = None
         while len(self._resolution_list) > 0:
@@ -416,6 +438,9 @@ def new_struct(self, elem):
     def new_operation(self, elem, req_val, rsp_val):
         return SpecOperation(self, elem, req_val, rsp_val)
 
+    def new_mcast_group(self, elem):
+        return SpecMcastGroup(self, elem)
+
     def add_unresolved(self, elem):
         self._resolution_list.append(elem)
 
@@ -512,3 +537,9 @@ def resolve(self):
                 self.ops[op.name] = op
             elif op.is_async:
                 self.ntfs[op.name] = op
+
+        mcgs = self.yaml.get('mcast-groups')
+        if mcgs:
+            for elem in mcgs['list']:
+                mcg = self.new_mcast_group(elem)
+                self.mcast_groups[elem['name']] = mcg