Thread (16 messages) 16 messages, 4 authors, 2023-07-26

Re: [PATCH net-next v1 2/3] tools/net/ynl: Add support for netlink-raw families

From: Jakub Kicinski <kuba@kernel.org>
Date: 2023-07-26 21:37:10

On Tue, 25 Jul 2023 17:22:04 +0100 Donald Hunter wrote:
Refactor the ynl code to encapsulate protocol-family specifics into
NetlinkProtocolFamily and GenlProtocolFamily.
+class SpecMcastGroup(SpecElement):
+    """Netlink Multicast Group
+
+    Information about a multicast group.
+
+    Attributes:
+        id        numerical id of this multicast group for netlink-raw
+        yaml      raw spec as loaded from the spec file
+    """
+    def __init__(self, family, yaml):
+        super().__init__(family, yaml)
+        self.id = self.yaml.get('id')
name, too?
quoted hunk ↗ jump to hunk
 class SpecFamily(SpecElement):
     """ Netlink Family Spec class.
 
@@ -343,6 +357,7 @@ 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 +399,7 @@ class SpecFamily(SpecElement):
         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 +432,9 @@ class SpecFamily(SpecElement):
     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 +531,9 @@ class SpecFamily(SpecElement):
                 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
Could you factor out the mcgroup changes to a separate patch?
quoted hunk ↗ jump to hunk
diff --git a/tools/net/ynl/lib/ynl.py b/tools/net/ynl/lib/ynl.py
index 3e2ade2194cd..7e877c43e10f 100644
--- a/tools/net/ynl/lib/ynl.py
+++ b/tools/net/ynl/lib/ynl.py
@@ -25,6 +25,7 @@ class Netlink:
     NETLINK_ADD_MEMBERSHIP = 1
     NETLINK_CAP_ACK = 10
     NETLINK_EXT_ACK = 11
+    NETLINK_GET_STRICT_CHK = 12
 
     # Netlink message
     NLMSG_ERROR = 2
@@ -153,6 +154,21 @@ class NlAttr:
             value[m.name] = decoded
         return value
 
+    @classmethod
+    def decode_enum(cls, raw, attr_spec, consts):
+        enum = consts[attr_spec['enum']]
+        if 'enum-as-flags' in attr_spec and attr_spec['enum-as-flags']:
+            i = 0
+            value = set()
+            while raw:
+                if raw & 1:
+                    value.add(enum.entries_by_val[i].name)
+                raw >>= 1
+                i += 1
+        else:
+            value = enum.entries_by_val[raw].name
+        return value
This doesn't always operates on netlink attributes, technically,
so how about we make it a standalone function, not a member of NlAttr?
Or should we move it to a parent class, NetlinkProtocolFamily?
+    def decode_fixed_header(self, consts, op):
+        fixed_header_members = consts[op.fixed_header].members
+        self.fixed_header_attrs = dict()
+        offset = 0
+        for m in fixed_header_members:
+            format = NlAttr.get_format(m.type, m.byte_order)
+            [ value ] = format.unpack_from(self.raw, offset)
+            offset += format.size
+
+            if m.enum:
+                value = NlAttr.decode_enum(value, m, consts)
+
+            self.fixed_header_attrs[m.name] = value
+        self.raw = self.raw[offset:]
+
+    def cmd(self):
+        return self.nl_type
And perhaps the pure code moves could be a separate patch for ease 
of review?
quoted hunk ↗ jump to hunk
     def __repr__(self):
         msg = f"nl_len = {self.nl_len} ({len(self.raw)}) nl_flags = 0x{self.nl_flags:x} nl_type = {self.nl_type}\n"
         if self.error:
@@ -318,23 +353,21 @@ def _genl_load_families():
 
 
 class GenlMsg:
-    def __init__(self, nl_msg, fixed_header_members=[]):
-        self.nl = nl_msg
+    def __init__(self, nl_msg, ynl=None):
+        self.genl_cmd, self.genl_version, _ = struct.unpack_from("BBH", nl_msg.raw, 0)
+        nl_msg.raw = nl_msg.raw[4:]
 
-        self.hdr = nl_msg.raw[0:4]
-        offset = 4
+        if ynl:
+            op = ynl.rsp_by_value[self.genl_cmd]
Took me a while to figure out why ynl gets passed here :S
I'm not sure what the best structure of inheritance is but
I think we should at the very least *not* call genl vs raw-nl
"family".

NetlinkProtocolFamily -> NetlinkProtocol
GenlProtocolFamily -> GenlProtocol

and store them in YnlFamily to self.nlproto or self.protocol
or some such.
+            if op.fixed_header:
+                nl_msg.decode_fixed_header(ynl.consts, op)
     def _decode_binary(self, attr, attr_spec):
         if attr_spec.struct_name:
             members = self.consts[attr_spec.struct_name]
-            decoded = attr.as_struct(members)
+            decoded = attr.as_struct(members, self.consts)
I applied the series on top of Arkadiusz's fixes and this line throws
an "as_struct takes 2 arguments, 3 given" exception.
             for m in members:
                 if m.enum:
                      decoded[m.name] = self._decode_enum(decoded[m.name], m)
  
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