tools: ynl: allow user to pass enum string instead of scalar value

During decoding of messages coming from kernel, attribute values are
converted to enum names in case the attribute type is enum of bitfield32.

However, when user constructs json message, he has to pass plain scalar
values. See "state" "selector" and "value" attributes in following
examples:

$ sudo ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/dpll.yaml --do pin-set --json '{"id": 0, "parent-device": {"parent-id": 0, "state": 1}}'
$ sudo ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/devlink.yaml --do port-set --json '{"bus-name": "pci", "dev-name": "0000:08:00.1", "port-index": 98304, "port-function": {"caps": {"selector": 1, "value": 1 }}}'

Allow user to pass strings containing enum names, convert them to scalar
values to be encoded into Netlink message:

$ sudo ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/dpll.yaml --do pin-set --json '{"id": 0, "parent-device": {"parent-id": 0, "state": "connected"}}'
$ sudo ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/devlink.yaml --do port-set --json '{"bus-name": "pci", "dev-name": "0000:08:00.1", "port-index": 98304, "port-function": {"caps": {"selector": ["roce-bit"], "value": ["roce-bit"] }}}'

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://lore.kernel.org/r/20240222134351.224704-4-jiri@resnulli.us
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/net/ynl/lib/ynl.py

@@ -438,6 +438,26 @@ def ntf_subscribe(self, mcast_name):
         self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_ADD_MEMBERSHIP,
                              mcast_id)
 
+    def _encode_enum(self, attr_spec, value):
+        enum = self.consts[attr_spec['enum']]
+        if enum.type == 'flags' or attr_spec.get('enum-as-flags', False):
+            scalar = 0
+            if isinstance(value, str):
+                value = [value]
+            for single_value in value:
+                scalar += enum.entries[single_value].user_value(as_flags = True)
+            return scalar
+        else:
+            return enum.entries[value].user_value()
+
+    def _get_scalar(self, attr_spec, value):
+        try:
+            return int(value)
+        except (ValueError, TypeError) as e:
+            if 'enum' not in attr_spec:
+                raise e
+        return self._encode_enum(attr_spec, value);
+
     def _add_attr(self, space, name, value, search_attrs):
         try:
             attr = self.attr_sets[space][name]
@@ -475,15 +495,17 @@ def _add_attr(self, space, name, value, search_attrs):
             else:
                 raise Exception(f'Unknown type for binary attribute, value: {value}')
         elif attr['type'] in NlAttr.type_formats or attr.is_auto_scalar:
-            scalar = int(value)
+            scalar = self._get_scalar(attr, value)
             if attr.is_auto_scalar:
                 attr_type = attr["type"][0] + ('32' if scalar.bit_length() <= 32 else '64')
             else:
                 attr_type = attr["type"]
             format = NlAttr.get_format(attr_type, attr.byte_order)
             attr_payload = format.pack(scalar)
         elif attr['type'] in "bitfield32":
-            attr_payload = struct.pack("II", int(value["value"]), int(value["selector"]))
+            scalar_value = self._get_scalar(attr, value["value"])
+            scalar_selector = self._get_scalar(attr, value["selector"])
+            attr_payload = struct.pack("II", scalar_value, scalar_selector)
         elif attr['type'] == 'sub-message':
             msg_format = self._resolve_selector(attr, search_attrs)
             attr_payload = b''