Merge branch 'tools-net-ynl-add-support-for-nlctrl-netlink-family'

Donald Hunter says:

====================
tools/net/ynl: Add support for nlctrl netlink family

This series adds a new YNL spec for the nlctrl family, plus some fixes
and enhancements for ynl.

Patch 1 fixes an extack decoding bug
Patch 2 gives cleaner netlink error reporting
Patch 3 fixes an array-nest codegen bug
Patch 4 adds nest-type-value support to ynl
Patch 5 fixes the ynl schemas to allow empty enum-name attrs
Patch 6 contains the nlctrl spec
====================

Link: https://lore.kernel.org/r/20240306231046.97158-1-donald.hunter@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/netlink/genetlink-c.yaml

@@ -126,8 +126,9 @@ properties:
             Prefix for the C enum name of the attributes. Default family[name]-set[name]-a-
           type: string
         enum-name:
-          description: Name for the enum type of the attribute.
-          type: string
+          description: |
+            Name for the enum type of the attribute, if empty no name will be used.
+          type: [ string, "null" ]
         doc:
           description: Documentation of the space.
           type: string
@@ -261,14 +262,16 @@ properties:
           the prefix with the upper case name of the command, with dashes replaced by underscores.
         type: string
       enum-name:
-        description: Name for the enum type with commands.
-        type: string
+        description: |
+          Name for the enum type with commands, if empty no name will be used.
+        type: [ string, "null" ]
       async-prefix:
         description: Same as name-prefix but used to render notifications and events to separate enum.
         type: string
       async-enum:
-        description: Name for the enum type with notifications/events.
-        type: string
+        description: |
+          Name for the enum type with commands, if empty no name will be used.
+        type: [ string, "null" ]
       list:
         description: List of commands
         type: array

Documentation/netlink/genetlink-legacy.yaml

@@ -168,8 +168,9 @@ properties:
             Prefix for the C enum name of the attributes. Default family[name]-set[name]-a-
           type: string
         enum-name:
-          description: Name for the enum type of the attribute.
-          type: string
+          description: |
+            Name for the enum type of the attribute, if empty no name will be used.
+          type: [ string, "null" ]
         doc:
           description: Documentation of the space.
           type: string
@@ -304,14 +305,16 @@ properties:
           the prefix with the upper case name of the command, with dashes replaced by underscores.
         type: string
       enum-name:
-        description: Name for the enum type with commands.
-        type: string
+        description: |
+          Name for the enum type with commands, if empty no name will be used.
+        type: [ string, "null" ]
       async-prefix:
         description: Same as name-prefix but used to render notifications and events to separate enum.
         type: string
       async-enum:
-        description: Name for the enum type with notifications/events.
-        type: string
+        description: |
+          Name for the enum type with commands, if empty no name will be used.
+        type: [ string, "null" ]
       # Start genetlink-legacy
       fixed-header: &fixed-header
         description: |

Documentation/netlink/netlink-raw.yaml

@@ -189,8 +189,9 @@ properties:
             Prefix for the C enum name of the attributes. Default family[name]-set[name]-a-
           type: string
         enum-name:
-          description: Name for the enum type of the attribute.
-          type: string
+          description: |
+            Name for the enum type of the attribute, if empty no name will be used.
+          type: [ string, "null" ]
         doc:
           description: Documentation of the space.
           type: string
@@ -371,14 +372,16 @@ properties:
           the prefix with the upper case name of the command, with dashes replaced by underscores.
         type: string
       enum-name:
-        description: Name for the enum type with commands.
-        type: string
+        description: |
+          Name for the enum type with commands, if empty no name will be used.
+        type: [ string, "null" ]
       async-prefix:
         description: Same as name-prefix but used to render notifications and events to separate enum.
         type: string
       async-enum:
-        description: Name for the enum type with notifications/events.
-        type: string
+        description: |
+          Name for the enum type with commands, if empty no name will be used.
+        type: [ string, "null" ]
       # Start genetlink-legacy
       fixed-header: &fixed-header
         description: |

Documentation/netlink/specs/nlctrl.yaml

+# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+
+name: nlctrl
+protocol: genetlink-legacy
+uapi-header: linux/genetlink.h
+
+doc: |
+  genetlink meta-family that exposes information about all genetlink
+  families registered in the kernel (including itself).
+
+definitions:
+  -
+    name: op-flags
+    type: flags
+    enum-name:
+    entries:
+      - admin-perm
+      - cmd-cap-do
+      - cmd-cap-dump
+      - cmd-cap-haspol
+      - uns-admin-perm
+  -
+    name: attr-type
+    enum-name: netlink-attribute-type
+    type: enum
+    entries:
+      - invalid
+      - flag
+      - u8
+      - u16
+      - u32
+      - u64
+      - s8
+      - s16
+      - s32
+      - s64
+      - binary
+      - string
+      - nul-string
+      - nested
+      - nested-array
+      - bitfield32
+      - sint
+      - uint
+
+attribute-sets:
+  -
+    name: ctrl-attrs
+    name-prefix: ctrl-attr-
+    attributes:
+      -
+        name: family-id
+        type: u16
+      -
+        name: family-name
+        type: string
+      -
+        name: version
+        type: u32
+      -
+        name: hdrsize
+        type: u32
+      -
+        name: maxattr
+        type: u32
+      -
+        name: ops
+        type: array-nest
+        nested-attributes: op-attrs
+      -
+        name: mcast-groups
+        type: array-nest
+        nested-attributes: mcast-group-attrs
+      -
+        name: policy
+        type: nest-type-value
+        type-value: [ policy-id, attr-id ]
+        nested-attributes: policy-attrs
+      -
+        name: op-policy
+        type: nest-type-value
+        type-value: [ op-id ]
+        nested-attributes: op-policy-attrs
+      -
+        name: op
+        type: u32
+  -
+    name: mcast-group-attrs
+    name-prefix: ctrl-attr-mcast-grp-
+    enum-name:
+    attributes:
+      -
+        name: name
+        type: string
+      -
+        name: id
+        type: u32
+  -
+    name: op-attrs
+    name-prefix: ctrl-attr-op-
+    enum-name:
+    attributes:
+      -
+        name: id
+        type: u32
+      -
+        name: flags
+        type: u32
+        enum: op-flags
+        enum-as-flags: true
+  -
+    name: policy-attrs
+    name-prefix: nl-policy-type-attr-
+    enum-name:
+    attributes:
+      -
+        name: type
+        type: u32
+        enum: attr-type
+      -
+        name: min-value-s
+        type: s64
+      -
+        name: max-value-s
+        type: s64
+      -
+        name: min-value-u
+        type: u64
+      -
+        name: max-value-u
+        type: u64
+      -
+        name: min-length
+        type: u32
+      -
+        name: max-length
+        type: u32
+      -
+        name: policy-idx
+        type: u32
+      -
+        name: policy-maxtype
+        type: u32
+      -
+        name: bitfield32-mask
+        type: u32
+      -
+        name: mask
+        type: u64
+      -
+        name: pad
+        type: pad
+  -
+    name: op-policy-attrs
+    name-prefix: ctrl-attr-policy-
+    enum-name:
+    attributes:
+      -
+        name: do
+        type: u32
+      -
+        name: dump
+        type: u32
+
+operations:
+  enum-model: directional
+  name-prefix: ctrl-cmd-
+  list:
+    -
+      name: getfamily
+      doc: Get / dump genetlink families
+      attribute-set: ctrl-attrs
+      do:
+        request:
+          value: 3
+          attributes:
+            - family-name
+        reply: &all-attrs
+          value: 1
+          attributes:
+            - family-id
+            - family-name
+            - hdrsize
+            - maxattr
+            - mcast-groups
+            - ops
+            - version
+      dump:
+        reply: *all-attrs
+    -
+      name: getpolicy
+      doc: Get / dump genetlink policies
+      attribute-set: ctrl-attrs
+      dump:
+        request:
+          value: 10
+          attributes:
+            - family-name
+            - family-id
+            - op
+        reply:
+          value: 10
+          attributes:
+            - family-id
+            - op-policy
+            - policy

tools/net/ynl/cli.py

@@ -6,7 +6,7 @@ import json
 import pprint
 import time
 
-from lib import YnlFamily, Netlink
+from lib import YnlFamily, Netlink, NlError
 
 
 class YnlEncoder(json.JSONEncoder):
@@ -66,12 +66,16 @@ def main():
     if args.sleep:
         time.sleep(args.sleep)
 
+    try:
         if args.do:
             reply = ynl.do(args.do, attrs, args.flags)
             output(reply)
         if args.dump:
             reply = ynl.dump(args.dump, attrs)
             output(reply)
+    except NlError as e:
+        print(e)
+        exit(1)
 
     if args.ntf:
         ynl.check_ntf()

tools/net/ynl/lib/__init__.py

@@ -2,7 +2,7 @@
 
 from .nlspec import SpecAttr, SpecAttrSet, SpecEnumEntry, SpecEnumSet, \
     SpecFamily, SpecOperation
-from .ynl import YnlFamily, Netlink
+from .ynl import YnlFamily, Netlink, NlError
 
 __all__ = ["SpecAttr", "SpecAttrSet", "SpecEnumEntry", "SpecEnumSet",
-           "SpecFamily", "SpecOperation", "YnlFamily", "Netlink"]
+           "SpecFamily", "SpecOperation", "YnlFamily", "Netlink", "NlError"]

tools/net/ynl/lib/ynl.py

@@ -353,6 +353,9 @@ class NetlinkProtocol:
             raise Exception(f'Multicast group "{mcast_name}" not present in the spec')
         return mcast_groups[mcast_name].value
 
+    def msghdr_size(self):
+        return 16
+
 
 class GenlProtocol(NetlinkProtocol):
     def __init__(self, family_name):
@@ -378,6 +381,8 @@ class GenlProtocol(NetlinkProtocol):
             raise Exception(f'Multicast group "{mcast_name}" not present in the family')
         return self.genl_family['mcast'][mcast_name]
 
+    def msghdr_size(self):
+        return super().msghdr_size() + 4
 
 
 class SpaceAttrs:
@@ -590,6 +595,16 @@ class YnlFamily(SpecFamily):
             decoded.append({ item.type: subattrs })
         return decoded
 
+    def _decode_nest_type_value(self, attr, attr_spec):
+        decoded = {}
+        value = attr
+        for name in attr_spec['type-value']:
+            value = NlAttr(value.raw, 0)
+            decoded[name] = value.type
+        subattrs = self._decode(NlAttrs(value.raw), attr_spec['nested-attributes'])
+        decoded.update(subattrs)
+        return decoded
+
     def _decode_unknown(self, attr):
         if attr.is_nest:
             return self._decode(NlAttrs(attr.raw), None)
@@ -681,6 +696,8 @@ class YnlFamily(SpecFamily):
                 decoded = {"value": value, "selector": selector}
             elif attr_spec["type"] == 'sub-message':
                 decoded = self._decode_sub_msg(attr, attr_spec, search_attrs)
+            elif attr_spec["type"] == 'nest-type-value':
+                decoded = self._decode_nest_type_value(attr, attr_spec)
             else:
                 if not self.process_unknown:
                     raise Exception(f'Unknown {attr_spec["type"]} with name {attr_spec["name"]}')
@@ -721,7 +738,7 @@ class YnlFamily(SpecFamily):
             return
 
         msg = self.nlproto.decode(self, NlMsg(request, 0, op.attr_set))
-        offset = 20 + self._struct_size(op.fixed_header)
+        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'])
         if path:

tools/net/ynl/ynl-gen-c.py

@@ -1667,7 +1667,7 @@ def _multi_parse(ri, struct, init_lines, local_vars):
         aspec = struct[anest]
 
         ri.cw.block_start(line=f"if (n_{aspec.c_name})")
-        ri.cw.p(f"dst->{aspec.c_name} = calloc({aspec.c_name}, sizeof(*dst->{aspec.c_name}));")
+        ri.cw.p(f"dst->{aspec.c_name} = calloc(n_{aspec.c_name}, sizeof(*dst->{aspec.c_name}));")
         ri.cw.p(f"dst->n_{aspec.c_name} = n_{aspec.c_name};")
         ri.cw.p('i = 0;')
         ri.cw.p(f"parg.rsp_policy = &{aspec.nested_render_name}_nest;")