tools/net/ynl: Fix extack decoding for directional ops

NetlinkProtocol.decode() was looking up ops by response value which breaks
when it is used for extack decoding of directional ops. Instead, pass
the op to decode().

Signed-off-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://lore.kernel.org/r/20240418104737.77914-3-donald.hunter@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/net/ynl/lib/ynl.py

@@ -386,12 +386,9 @@ def message(self, flags, command, version, seq=None):
     def _decode(self, nl_msg):
         return nl_msg
 
-    def decode(self, ynl, nl_msg):
+    def decode(self, ynl, nl_msg, op):
         msg = self._decode(nl_msg)
-        fixed_header_size = 0
-        if ynl:
-            op = ynl.rsp_by_value[msg.cmd()]
-            fixed_header_size = ynl._struct_size(op.fixed_header)
+        fixed_header_size = ynl._struct_size(op.fixed_header)
         msg.raw_attrs = NlAttrs(msg.raw, fixed_header_size)
         return msg
 
@@ -797,7 +794,7 @@ def _decode_extack(self, request, op, extack):
         if 'bad-attr-offs' not in extack:
             return
 
-        msg = self.nlproto.decode(self, NlMsg(request, 0, op.attr_set))
+        msg = self.nlproto.decode(self, NlMsg(request, 0, op.attr_set), op)
         offset = self.nlproto.msghdr_size() + self._struct_size(op.fixed_header)
         path = self._decode_extack_path(msg.raw_attrs, op.attr_set, offset,
                                         extack['bad-attr-offs'])
@@ -922,7 +919,8 @@ def check_ntf(self):
                     print("Netlink done while checking for ntf!?")
                     continue
 
-                decoded = self.nlproto.decode(self, nl_msg)
+                op = self.rsp_by_value[nl_msg.cmd()]
+                decoded = self.nlproto.decode(self, nl_msg, op)
                 if decoded.cmd() not in self.async_msg_ids:
                     print("Unexpected msg id done while checking for ntf", decoded)
                     continue
@@ -979,7 +977,7 @@ def _op(self, method, vals, flags=None, dump=False):
                     done = True
                     break
 
-                decoded = self.nlproto.decode(self, nl_msg)
+                decoded = self.nlproto.decode(self, nl_msg, op)
 
                 # Check if this is a reply to our request
                 if nl_msg.nl_seq != req_seq or decoded.cmd() != op.rsp_value: