Merge branch 'tools-net-ynl-add-support-for-netlink-raw-families'

Donald Hunter says:

====================
tools/net/ynl: Add support for netlink-raw families

This patchset adds support for netlink-raw families such as rtnetlink.

Patch 1 fixes a typo in existing schemas
Patch 2 contains the schema definition
Patches 3 & 4 update the schema documentation
Patches 5 - 9 extends ynl
Patches 10 - 12 add several netlink-raw specs

The netlink-raw schema is very similar to genetlink-legacy and I thought
about making the changes there and symlinking to it. On balance I
thought that might be problematic for accurate schema validation.

rtnetlink doesn't seem to fit into unified or directional message
enumeration models. It seems like an 'explicit' model would be useful,
to force the schema author to specify the message ids directly.

There is not yet support for notifications because ynl currently doesn't
support defining 'event' properties on a 'do' operation. The message ids
are shared so ops need to be both sync and async. I plan to look at this
in a future patch.

The link and route messages contain different nested attributes
dependent on the type of link or route. Decoding these will need some
kind of attr-space selection that uses the value of another attribute as
the selector key. These nested attributes have been left with type
'binary' for now.
====================

Link: https://lore.kernel.org/r/20230825122756.7603-1-donald.hunter@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/core-api/netlink.rst

@@ -67,10 +67,11 @@ Globals
 kernel-policy
 ~~~~~~~~~~~~~
 
-Defines if the kernel validation policy is per operation (``per-op``)
-or for the entire family (``global``). New families should use ``per-op``
-(default) to be able to narrow down the attributes accepted by a specific
-command.
+Defines whether the kernel validation policy is ``global`` i.e. the same for all
+operations of the family, defined for each operation individually - ``per-op``,
+or separately for each operation and operation type (do vs dump) - ``split``.
+New families should use ``per-op`` (default) to be able to narrow down the
+attributes accepted by a specific command.
 
 checks
 ------

Documentation/netlink/genetlink-c.yaml

@@ -41,7 +41,7 @@ properties:
     description: Name of the define for the family name.
     type: string
   c-version-name:
-    description: Name of the define for the verion of the family.
+    description: Name of the define for the version of the family.
     type: string
   max-by-define:
     description: Makes the number of attributes and commands be specified by a define, not an enum value.

Documentation/netlink/genetlink-legacy.yaml

@@ -41,7 +41,7 @@ properties:
     description: Name of the define for the family name.
     type: string
   c-version-name:
-    description: Name of the define for the verion of the family.
+    description: Name of the define for the version of the family.
     type: string
   max-by-define:
     description: Makes the number of attributes and commands be specified by a define, not an enum value.

Documentation/netlink/netlink-raw.yaml

@@ -0,0 +1,410 @@
+# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+%YAML 1.2
+---
+$id: http://kernel.org/schemas/netlink/netlink-raw.yaml#
+$schema: https://json-schema.org/draft-07/schema
+
+# Common defines
+$defs:
+  uint:
+    type: integer
+    minimum: 0
+  len-or-define:
+    type: [ string, integer ]
+    pattern: ^[0-9A-Za-z_]+( - 1)?$
+    minimum: 0
+
+# Schema for specs
+title: Protocol
+description: Specification of a raw netlink protocol
+type: object
+required: [ name, doc, attribute-sets, operations ]
+additionalProperties: False
+properties:
+  name:
+    description: Name of the netlink family.
+    type: string
+  doc:
+    type: string
+  protocol:
+    description: Schema compatibility level.
+    enum: [ netlink-raw ] # Trim
+  # Start netlink-raw
+  protonum:
+    description: Protocol number to use for netlink-raw
+    type: integer
+  # End netlink-raw
+  uapi-header:
+    description: Path to the uAPI header, default is linux/${family-name}.h
+    type: string
+  # Start genetlink-c
+  c-family-name:
+    description: Name of the define for the family name.
+    type: string
+  c-version-name:
+    description: Name of the define for the version of the family.
+    type: string
+  max-by-define:
+    description: Makes the number of attributes and commands be specified by a define, not an enum value.
+    type: boolean
+  # End genetlink-c
+  # Start genetlink-legacy
+  kernel-policy:
+    description: |
+      Defines if the input policy in the kernel is global, per-operation, or split per operation type.
+      Default is split.
+    enum: [ split, per-op, global ]
+  # End genetlink-legacy
+
+  definitions:
+    description: List of type and constant definitions (enums, flags, defines).
+    type: array
+    items:
+      type: object
+      required: [ type, name ]
+      additionalProperties: False
+      properties:
+        name:
+          type: string
+        header:
+          description: For C-compatible languages, header which already defines this value.
+          type: string
+        type:
+          enum: [ const, enum, flags, struct ] # Trim
+        doc:
+          type: string
+        # For const
+        value:
+          description: For const - the value.
+          type: [ string, integer ]
+        # For enum and flags
+        value-start:
+          description: For enum or flags the literal initializer for the first value.
+          type: [ string, integer ]
+        entries:
+          description: For enum or flags array of values.
+          type: array
+          items:
+            oneOf:
+              - type: string
+              - type: object
+                required: [ name ]
+                additionalProperties: False
+                properties:
+                  name:
+                    type: string
+                  value:
+                    type: integer
+                  doc:
+                    type: string
+        render-max:
+          description: Render the max members for this enum.
+          type: boolean
+        # Start genetlink-c
+        enum-name:
+          description: Name for enum, if empty no name will be used.
+          type: [ string, "null" ]
+        name-prefix:
+          description: For enum the prefix of the values, optional.
+          type: string
+        # End genetlink-c
+        # Start genetlink-legacy
+        members:
+          description: List of struct members. Only scalars and strings members allowed.
+          type: array
+          items:
+            type: object
+            required: [ name, type ]
+            additionalProperties: False
+            properties:
+              name:
+                type: string
+              type:
+                description: The netlink attribute type
+                enum: [ u8, u16, u32, u64, s8, s16, s32, s64, string, binary ]
+              len:
+                $ref: '#/$defs/len-or-define'
+              byte-order:
+                enum: [ little-endian, big-endian ]
+              doc:
+                description: Documentation for the struct member attribute.
+                type: string
+              enum:
+                description: Name of the enum type used for the attribute.
+                type: string
+              enum-as-flags:
+                description: |
+                  Treat the enum as flags. In most cases enum is either used as flags or as values.
+                  Sometimes, however, both forms are necessary, in which case header contains the enum
+                  form while specific attributes may request to convert the values into a bitfield.
+                type: boolean
+              display-hint: &display-hint
+                description: |
+                  Optional format indicator that is intended only for choosing
+                  the right formatting mechanism when displaying values of this
+                  type.
+                enum: [ hex, mac, fddi, ipv4, ipv6, uuid ]
+        # End genetlink-legacy
+
+  attribute-sets:
+    description: Definition of attribute spaces for this family.
+    type: array
+    items:
+      description: Definition of a single attribute space.
+      type: object
+      required: [ name, attributes ]
+      additionalProperties: False
+      properties:
+        name:
+          description: |
+            Name used when referring to this space in other definitions, not used outside of the spec.
+          type: string
+        name-prefix:
+          description: |
+            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
+        doc:
+          description: Documentation of the space.
+          type: string
+        subset-of:
+          description: |
+            Name of another space which this is a logical part of. Sub-spaces can be used to define
+            a limited group of attributes which are used in a nest.
+          type: string
+        # Start genetlink-c
+        attr-cnt-name:
+          description: The explicit name for constant holding the count of attributes (last attr + 1).
+          type: string
+        attr-max-name:
+          description: The explicit name for last member of attribute enum.
+          type: string
+        # End genetlink-c
+        attributes:
+          description: List of attributes in the space.
+          type: array
+          items:
+            type: object
+            required: [ name, type ]
+            additionalProperties: False
+            properties:
+              name:
+                type: string
+              type: &attr-type
+                description: The netlink attribute type
+                enum: [ unused, pad, flag, binary, u8, u16, u32, u64, s32, s64,
+                        string, nest, array-nest, nest-type-value ]
+              doc:
+                description: Documentation of the attribute.
+                type: string
+              value:
+                description: Value for the enum item representing this attribute in the uAPI.
+                $ref: '#/$defs/uint'
+              type-value:
+                description: Name of the value extracted from the type of a nest-type-value attribute.
+                type: array
+                items:
+                  type: string
+              byte-order:
+                enum: [ little-endian, big-endian ]
+              multi-attr:
+                type: boolean
+              nested-attributes:
+                description: Name of the space (sub-space) used inside the attribute.
+                type: string
+              enum:
+                description: Name of the enum type used for the attribute.
+                type: string
+              enum-as-flags:
+                description: |
+                  Treat the enum as flags. In most cases enum is either used as flags or as values.
+                  Sometimes, however, both forms are necessary, in which case header contains the enum
+                  form while specific attributes may request to convert the values into a bitfield.
+                type: boolean
+              checks:
+                description: Kernel input validation.
+                type: object
+                additionalProperties: False
+                properties:
+                  flags-mask:
+                    description: Name of the flags constant on which to base mask (unsigned scalar types only).
+                    type: string
+                  min:
+                    description: Min value for an integer attribute.
+                    type: integer
+                  min-len:
+                    description: Min length for a binary attribute.
+                    $ref: '#/$defs/len-or-define'
+                  max-len:
+                    description: Max length for a string or a binary attribute.
+                    $ref: '#/$defs/len-or-define'
+              sub-type: *attr-type
+              display-hint: *display-hint
+              # Start genetlink-c
+              name-prefix:
+                type: string
+              # End genetlink-c
+              # Start genetlink-legacy
+              struct:
+                description: Name of the struct type used for the attribute.
+                type: string
+              # End genetlink-legacy
+
+      # Make sure name-prefix does not appear in subsets (subsets inherit naming)
+      dependencies:
+        name-prefix:
+          not:
+            required: [ subset-of ]
+        subset-of:
+          not:
+            required: [ name-prefix ]
+
+  operations:
+    description: Operations supported by the protocol.
+    type: object
+    required: [ list ]
+    additionalProperties: False
+    properties:
+      enum-model:
+        description: |
+          The model of assigning values to the operations.
+          "unified" is the recommended model where all message types belong
+          to a single enum.
+          "directional" has the messages sent to the kernel and from the kernel
+          enumerated separately.
+        enum: [ unified, directional ] # Trim
+      name-prefix:
+        description: |
+          Prefix for the C enum name of the command. The name is formed by concatenating
+          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
+      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
+      # Start genetlink-legacy
+      fixed-header: &fixed-header
+        description: |
+          Name of the structure defining the optional fixed-length protocol
+          header. This header is placed in a message after the netlink and
+          genetlink headers and before any attributes.
+        type: string
+      # End genetlink-legacy
+      list:
+        description: List of commands
+        type: array
+        items:
+          type: object
+          additionalProperties: False
+          required: [ name, doc ]
+          properties:
+            name:
+              description: Name of the operation, also defining its C enum value in uAPI.
+              type: string
+            doc:
+              description: Documentation for the command.
+              type: string
+            value:
+              description: Value for the enum in the uAPI.
+              $ref: '#/$defs/uint'
+            attribute-set:
+              description: |
+                Attribute space from which attributes directly in the requests and replies
+                to this command are defined.
+              type: string
+            flags: &cmd_flags
+              description: Command flags.
+              type: array
+              items:
+                enum: [ admin-perm ]
+            dont-validate:
+              description: Kernel attribute validation flags.
+              type: array
+              items:
+                enum: [ strict, dump ]
+            # Start genetlink-legacy
+            fixed-header: *fixed-header
+            # End genetlink-legacy
+            do: &subop-type
+              description: Main command handler.
+              type: object
+              additionalProperties: False
+              properties:
+                request: &subop-attr-list
+                  description: Definition of the request message for a given command.
+                  type: object
+                  additionalProperties: False
+                  properties:
+                    attributes:
+                      description: |
+                        Names of attributes from the attribute-set (not full attribute
+                        definitions, just names).
+                      type: array
+                      items:
+                        type: string
+                    # Start genetlink-legacy
+                    value:
+                      description: |
+                        ID of this message if value for request and response differ,
+                        i.e. requests and responses have different message enums.
+                      $ref: '#/$defs/uint'
+                    # End genetlink-legacy
+                reply: *subop-attr-list
+                pre:
+                  description: Hook for a function to run before the main callback (pre_doit or start).
+                  type: string
+                post:
+                  description: Hook for a function to run after the main callback (post_doit or done).
+                  type: string
+            dump: *subop-type
+            notify:
+              description: Name of the command sharing the reply type with this notification.
+              type: string
+            event:
+              type: object
+              additionalProperties: False
+              properties:
+                attributes:
+                  description: Explicit list of the attributes for the notification.
+                  type: array
+                  items:
+                    type: string
+            mcgrp:
+              description: Name of the multicast group generating given notification.
+              type: string
+  mcast-groups:
+    description: List of multicast groups.
+    type: object
+    required: [ list ]
+    additionalProperties: False
+    properties:
+      list:
+        description: List of groups.
+        type: array
+        items:
+          type: object
+          required: [ name ]
+          additionalProperties: False
+          properties:
+            name:
+              description: |
+                The name for the group, used to form the define and the value of the define.
+              type: string
+            # Start genetlink-c
+            c-define-name:
+              description: Override for the name of the define in C uAPI.
+              type: string
+            # End genetlink-c
+            flags: *cmd_flags
+            # Start netlink-raw
+            value:
+              description: Value of the netlink multicast group in the uAPI.
+              type: integer
+            # End netlink-raw

Documentation/netlink/specs/rt_addr.yaml

@@ -0,0 +1,179 @@
+# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+
+name: rt-addr
+protocol: netlink-raw
+protonum: 0
+
+doc:
+  Address configuration over rtnetlink.
+
+definitions:
+  -
+    name: ifaddrmsg
+    type: struct
+    members:
+      -
+        name: ifa-family
+        type: u8
+      -
+        name: ifa-prefixlen
+        type: u8
+      -
+        name: ifa-flags
+        type: u8
+        enum: ifa-flags
+        enum-as-flags: true
+      -
+        name: ifa-scope
+        type: u8
+      -
+        name: ifa-index
+        type: u32
+  -
+    name: ifa-cacheinfo
+    type: struct
+    members:
+      -
+        name: ifa-prefered
+        type: u32
+      -
+        name: ifa-valid
+        type: u32
+      -
+        name: cstamp
+        type: u32
+      -
+        name: tstamp
+        type: u32
+
+  -
+    name: ifa-flags
+    type: flags
+    entries:
+      -
+        name: secondary
+      -
+        name: nodad
+      -
+        name: optimistic
+      -
+        name: dadfailed
+      -
+        name: homeaddress
+      -
+        name: deprecated
+      -
+        name: tentative
+      -
+        name: permanent
+      -
+        name: managetempaddr
+      -
+        name: noprefixroute
+      -
+        name: mcautojoin
+      -
+        name: stable-privacy
+
+attribute-sets:
+  -
+    name: addr-attrs
+    attributes:
+      -
+        name: ifa-address
+        type: binary
+        display-hint: ipv4
+      -
+        name: ifa-local
+        type: binary
+        display-hint: ipv4
+      -
+        name: ifa-label
+        type: string
+      -
+        name: ifa-broadcast
+        type: binary
+        display-hint: ipv4
+      -
+        name: ifa-anycast
+        type: binary
+      -
+        name: ifa-cacheinfo
+        type: binary
+        struct: ifa-cacheinfo
+      -
+        name: ifa-multicast
+        type: binary
+      -
+        name: ifa-flags
+        type: u32
+        enum: ifa-flags
+        enum-as-flags: true
+      -
+        name: ifa-rt-priority
+        type: u32
+      -
+        name: ifa-target-netnsid
+        type: binary
+      -
+        name: ifa-proto
+        type: u8
+
+
+operations:
+  fixed-header: ifaddrmsg
+  enum-model: directional
+  list:
+    -
+      name: newaddr
+      doc: Add new address
+      attribute-set: addr-attrs
+      do:
+        request:
+          value: 20
+          attributes: &ifaddr-all
+            - ifa-family
+            - ifa-flags
+            - ifa-prefixlen
+            - ifa-scope
+            - ifa-index
+            - ifa-address
+            - ifa-label
+            - ifa-local
+            - ifa-cacheinfo
+    -
+      name: deladdr
+      doc: Remove address
+      attribute-set: addr-attrs
+      do:
+        request:
+          value: 21
+          attributes:
+            - ifa-family
+            - ifa-flags
+            - ifa-prefixlen
+            - ifa-scope
+            - ifa-index
+            - ifa-address
+            - ifa-local
+    -
+      name: getaddr
+      doc: Dump address information.
+      attribute-set: addr-attrs
+      dump:
+        request:
+          value: 22
+          attributes:
+            - ifa-index
+        reply:
+          value: 20
+          attributes: *ifaddr-all
+
+mcast-groups:
+  list:
+    -
+      name: rtnlgrp-ipv4-ifaddr
+      value: 5
+    -
+      name: rtnlgrp-ipv6-ifaddr
+      value: 9

Documentation/netlink/specs/rt_route.yaml

@@ -0,0 +1,327 @@
+# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+
+name: rt-route
+protocol: netlink-raw
+protonum: 0
+
+doc:
+  Route configuration over rtnetlink.
+
+definitions:
+  -
+    name: rtm-type
+    name-prefix: rtn-
+    type: enum
+    entries:
+      - unspec
+      - unicast
+      - local
+      - broadcast
+      - anycast
+      - multicast
+      - blackhole
+      - unreachable
+      - prohibit
+      - throw
+      - nat
+      - xresolve
+  -
+    name: rtmsg
+    type: struct
+    members:
+      -
+        name: rtm-family
+        type: u8
+      -
+        name: rtm-dst-len
+        type: u8
+      -
+        name: rtm-src-len
+        type: u8
+      -
+        name: rtm-tos
+        type: u8
+      -
+        name: rtm-table
+        type: u8
+      -
+        name: rtm-protocol
+        type: u8
+      -
+        name: rtm-scope
+        type: u8
+      -
+        name: rtm-type
+        type: u8
+        enum: rtm-type
+      -
+        name: rtm-flags
+        type: u32
+  -
+    name: rta-cacheinfo
+    type: struct
+    members:
+      -
+        name: rta-clntref
+        type: u32
+      -
+        name: rta-lastuse
+        type: u32
+      -
+        name: rta-expires
+        type: u32
+      -
+        name: rta-error
+        type: u32
+      -
+        name: rta-used
+        type: u32
+
+attribute-sets:
+  -
+    name: route-attrs
+    attributes:
+      -
+        name: rta-dst
+        type: binary
+        display-hint: ipv4
+      -
+        name: rta-src
+        type: binary
+        display-hint: ipv4
+      -
+        name: rta-iif
+        type: u32
+      -
+        name: rta-oif
+        type: u32
+      -
+        name: rta-gateway
+        type: binary
+        display-hint: ipv4
+      -
+        name: rta-priority
+        type: u32
+      -
+        name: rta-prefsrc
+        type: binary
+        display-hint: ipv4
+      -
+        name: rta-metrics
+        type: nest
+        nested-attributes: rta-metrics
+      -
+        name: rta-multipath
+        type: binary
+      -
+        name: rta-protoinfo # not used
+        type: binary
+      -
+        name: rta-flow
+        type: u32
+      -
+        name: rta-cacheinfo
+        type: binary
+        struct: rta-cacheinfo
+      -
+        name: rta-session # not used
+        type: binary
+      -
+        name: rta-mp-algo # not used
+        type: binary
+      -
+        name: rta-table
+        type: u32
+      -
+        name: rta-mark
+        type: u32
+      -
+        name: rta-mfc-stats
+        type: binary
+      -
+        name: rta-via
+        type: binary
+      -
+        name: rta-newdst
+        type: binary
+      -
+        name: rta-pref
+        type: u8
+      -
+        name: rta-encap-type
+        type: u16
+      -
+        name: rta-encap
+        type: binary # tunnel specific nest
+      -
+        name: rta-expires
+        type: u32
+      -
+        name: rta-pad
+        type: binary
+      -
+        name: rta-uid
+        type: u32
+      -
+        name: rta-ttl-propagate
+        type: u8
+      -
+        name: rta-ip-proto
+        type: u8
+      -
+        name: rta-sport
+        type: u16
+      -
+        name: rta-dport
+        type: u16
+      -
+        name: rta-nh-id
+        type: u32
+  -
+    name: rta-metrics
+    attributes:
+      -
+        name: rtax-unspec
+        type: unused
+        value: 0
+      -
+        name: rtax-lock
+        type: u32
+      -
+        name: rtax-mtu
+        type: u32
+      -
+        name: rtax-window
+        type: u32
+      -
+        name: rtax-rtt
+        type: u32
+      -
+        name: rtax-rttvar
+        type: u32
+      -
+        name: rtax-ssthresh
+        type: u32
+      -
+        name: rtax-cwnd
+        type: u32
+      -
+        name: rtax-advmss
+        type: u32
+      -
+        name: rtax-reordering
+        type: u32
+      -
+        name: rtax-hoplimit
+        type: u32
+      -
+        name: rtax-initcwnd
+        type: u32
+      -
+        name: rtax-features
+        type: u32
+      -
+        name: rtax-rto-min
+        type: u32
+      -
+        name: rtax-initrwnd
+        type: u32
+      -
+        name: rtax-quickack
+        type: u32
+      -
+        name: rtax-cc-algo
+        type: string
+      -
+        name: rtax-fastopen-no-cookie
+        type: u32
+
+operations:
+  enum-model: directional
+  list:
+    -
+      name: getroute
+      doc: Dump route information.
+      attribute-set: route-attrs
+      fixed-header: rtmsg
+      do:
+        request:
+          value: 26
+          attributes:
+            - rtm-family
+            - rta-src
+            - rtm-src-len
+            - rta-dst
+            - rtm-dst-len
+            - rta-iif
+            - rta-oif
+            - rta-ip-proto
+            - rta-sport
+            - rta-dport
+            - rta-mark
+            - rta-uid
+        reply:
+          value: 24
+          attributes: &all-route-attrs
+            - rtm-family
+            - rtm-dst-len
+            - rtm-src-len
+            - rtm-tos
+            - rtm-table
+            - rtm-protocol
+            - rtm-scope
+            - rtm-type
+            - rtm-flags
+            - rta-dst
+            - rta-src
+            - rta-iif
+            - rta-oif
+            - rta-gateway
+            - rta-priority
+            - rta-prefsrc
+            - rta-metrics
+            - rta-multipath
+            - rta-flow
+            - rta-cacheinfo
+            - rta-table
+            - rta-mark
+            - rta-mfc-stats
+            - rta-via
+            - rta-newdst
+            - rta-pref
+            - rta-encap-type
+            - rta-encap
+            - rta-expires
+            - rta-pad
+            - rta-uid
+            - rta-ttl-propagate
+            - rta-ip-proto
+            - rta-sport
+            - rta-dport
+            - rta-nh-id
+      dump:
+        request:
+          value: 26
+          attributes:
+            - rtm-family
+        reply:
+          value: 24
+          attributes: *all-route-attrs
+    -
+      name: newroute
+      doc: Create a new route
+      attribute-set: route-attrs
+      fixed-header: rtmsg
+      do:
+        request:
+          value: 24
+          attributes: *all-route-attrs
+    -
+      name: delroute
+      doc: Delete an existing route
+      attribute-set: route-attrs
+      fixed-header: rtmsg
+      do:
+        request:
+          value: 25
+          attributes: *all-route-attrs

Documentation/userspace-api/netlink/genetlink-legacy.rst

@@ -8,11 +8,8 @@ This document describes the many additional quirks and properties
 required to describe older Generic Netlink families which form
 the ``genetlink-legacy`` protocol level.
 
-The spec is a work in progress, some of the quirks are just documented
-for future reference.
-
-Specification (defined)
-=======================
+Specification
+=============
 
 Attribute type nests
 --------------------
@@ -156,16 +153,27 @@ it will be allocated 3 for the request (``a`` is the previous operation
 with a request section and the value of 2) and 8 for response (``c`` is
 the previous operation in the "from-kernel" direction).
 
-Other quirks (todo)
-===================
+Other quirks
+============
 
 Structures
 ----------
 
 Legacy families can define C structures both to be used as the contents of
 an attribute and as a fixed message header. Structures are defined in
-``definitions``  and referenced in operations or attributes. Note that
-structures defined in YAML are implicitly packed according to C
+``definitions``  and referenced in operations or attributes.
+
+members
+~~~~~~~
+
+ - ``name`` - The attribute name of the struct member
+ - ``type`` - One of the scalar types ``u8``, ``u16``, ``u32``, ``u64``, ``s8``,
+   ``s16``, ``s32``, ``s64``, ``string`` or ``binary``.
+ - ``byte-order`` - ``big-endian`` or ``little-endian``
+ - ``doc``, ``enum``, ``enum-as-flags``, ``display-hint`` - Same as for
+   :ref:`attribute definitions <attribute_properties>`
+
+Note that structures defined in YAML are implicitly packed according to C
 conventions. For example, the following struct is 4 bytes, not 6 bytes:
 
 .. code-block:: c

Documentation/userspace-api/netlink/index.rst

@@ -14,5 +14,6 @@ Netlink documentation for users.
    specs
    c-code-gen
    genetlink-legacy
+   netlink-raw
 
 See also :ref:`Documentation/core-api/netlink.rst <kernel_netlink>`.

Documentation/userspace-api/netlink/netlink-raw.rst

@@ -0,0 +1,58 @@
+.. SPDX-License-Identifier: BSD-3-Clause
+
+======================================================
+Netlink specification support for raw Netlink families
+======================================================
+
+This document describes the additional properties required by raw Netlink
+families such as ``NETLINK_ROUTE`` which use the ``netlink-raw`` protocol
+specification.
+
+Specification
+=============
+
+The netlink-raw schema extends the :doc:`genetlink-legacy <genetlink-legacy>`
+schema with properties that are needed to specify the protocol numbers and
+multicast IDs used by raw netlink families. See :ref:`classic_netlink` for more
+information.
+
+Globals
+-------
+
+protonum
+~~~~~~~~
+
+The ``protonum`` property is used to specify the protocol number to use when
+opening a netlink socket.
+
+.. code-block:: yaml
+
+  # SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+
+  name: rt-addr
+  protocol: netlink-raw
+  protonum: 0             # part of the NETLINK_ROUTE protocol
+
+
+Multicast group properties
+--------------------------
+
+value
+~~~~~
+
+The ``value`` property is used to specify the group ID to use for multicast
+group registration.
+
+.. code-block:: yaml
+
+  mcast-groups:
+    list:
+      -
+        name: rtnlgrp-ipv4-ifaddr
+        value: 5
+      -
+        name: rtnlgrp-ipv6-ifaddr
+        value: 9
+      -
+        name: rtnlgrp-mctp-ifaddr
+        value: 34

Documentation/userspace-api/netlink/specs.rst

@@ -68,6 +68,10 @@ The following sections describe the properties of the most modern ``genetlink``
 schema. See the documentation of :doc:`genetlink-c <c-code-gen>`
 for information on how C names are derived from name properties.
 
+See also :ref:`Documentation/core-api/netlink.rst <kernel_netlink>` for
+information on the Netlink specification properties that are only relevant to
+the kernel space and not part of the user space API.
+
 genetlink
 =========
 
@@ -180,6 +184,8 @@ attributes
 
 List of attributes in the set.
 
+.. _attribute_properties:
+
 Attribute properties
 --------------------
 
@@ -264,6 +270,13 @@ a C array of u32 values can be specified with ``type: binary`` and
 ``sub-type: u32``. Binary types and legacy array formats are described in
 more detail in :doc:`genetlink-legacy`.
 
+display-hint
+~~~~~~~~~~~~
+
+Optional format indicator that is intended only for choosing the right
+formatting mechanism when displaying values of this type. Currently supported
+hints are ``hex``, ``mac``, ``fddi``, ``ipv4``, ``ipv6`` and ``uuid``.
+
 operations
 ----------
 

tools/net/ynl/cli.py

@@ -6,7 +6,7 @@ import json
 import pprint
 import time
 
-from lib import YnlFamily
+from lib import YnlFamily, Netlink
 
 
 def main():
@@ -19,6 +19,14 @@ def main():
     parser.add_argument('--dump', dest='dump', type=str)
     parser.add_argument('--sleep', dest='sleep', type=int)
     parser.add_argument('--subscribe', dest='ntf', type=str)
+    parser.add_argument('--replace', dest='flags', action='append_const',
+                        const=Netlink.NLM_F_REPLACE)
+    parser.add_argument('--excl', dest='flags', action='append_const',
+                        const=Netlink.NLM_F_EXCL)
+    parser.add_argument('--create', dest='flags', action='append_const',
+                        const=Netlink.NLM_F_CREATE)
+    parser.add_argument('--append', dest='flags', action='append_const',
+                        const=Netlink.NLM_F_APPEND)
     args = parser.parse_args()
 
     if args.no_schema:
@@ -37,7 +45,7 @@ def main():
         time.sleep(args.sleep)
 
     if args.do:
-        reply = ynl.do(args.do, attrs)
+        reply = ynl.do(args.do, attrs, args.flags)
         pprint.PrettyPrinter().pprint(reply)
     if args.dump:
         reply = ynl.dump(args.dump, attrs)

tools/net/ynl/lib/__init__.py

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

tools/net/ynl/lib/nlspec.py

@@ -322,6 +322,26 @@ class SpecOperation(SpecElement):
             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 @@ 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 +438,9 @@ 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 +537,9 @@ 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

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
@@ -34,6 +35,10 @@ class Netlink:
     NLM_F_ACK = 4
     NLM_F_ROOT = 0x100
     NLM_F_MATCH = 0x200
+
+    NLM_F_REPLACE = 0x100
+    NLM_F_EXCL = 0x200
+    NLM_F_CREATE = 0x400
     NLM_F_APPEND = 0x800
 
     NLM_F_CAPPED = 0x100
@@ -228,6 +233,9 @@ class NlMsg:
                             desc += f" ({spec['doc']})"
                         self.extack['miss-type'] = desc
 
+    def cmd(self):
+        return self.nl_type
+
     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:
@@ -293,7 +301,7 @@ def _genl_load_families():
 
                 gm = GenlMsg(nl_msg)
                 fam = dict()
-                for attr in gm.raw_attrs:
+                for attr in NlAttrs(gm.raw):
                     if attr.type == Netlink.CTRL_ATTR_FAMILY_ID:
                         fam['id'] = attr.as_scalar('u16')
                     elif attr.type == Netlink.CTRL_ATTR_FAMILY_NAME:
@@ -317,23 +325,13 @@ def _genl_load_families():
 
 
 class GenlMsg:
-    def __init__(self, nl_msg, fixed_header_members=[]):
+    def __init__(self, nl_msg):
         self.nl = nl_msg
+        self.genl_cmd, self.genl_version, _ = struct.unpack_from("BBH", nl_msg.raw, 0)
+        self.raw = nl_msg.raw[4:]
 
-        self.hdr = nl_msg.raw[0:4]
-        offset = 4
-
-        self.genl_cmd, self.genl_version, _ = struct.unpack("BBH", self.hdr)
-
-        self.fixed_header_attrs = dict()
-        for m in fixed_header_members:
-            format = NlAttr.get_format(m.type, m.byte_order)
-            decoded = format.unpack_from(nl_msg.raw, offset)
-            offset += format.size
-            self.fixed_header_attrs[m.name] = decoded[0]
-
-        self.raw = nl_msg.raw[offset:]
-        self.raw_attrs = NlAttrs(self.raw)
+    def cmd(self):
+        return self.genl_cmd
 
     def __repr__(self):
         msg = repr(self.nl)
@@ -343,9 +341,41 @@ class GenlMsg:
         return msg
 
 
-class GenlFamily:
-    def __init__(self, family_name):
+class NetlinkProtocol:
+    def __init__(self, family_name, proto_num):
         self.family_name = family_name
+        self.proto_num = proto_num
+
+    def _message(self, nl_type, nl_flags, seq=None):
+        if seq is None:
+            seq = random.randint(1, 1024)
+        nlmsg = struct.pack("HHII", nl_type, nl_flags, seq, 0)
+        return nlmsg
+
+    def message(self, flags, command, version, seq=None):
+        return self._message(command, flags, seq)
+
+    def _decode(self, nl_msg):
+        return nl_msg
+
+    def decode(self, ynl, nl_msg):
+        msg = self._decode(nl_msg)
+        fixed_header_size = 0
+        if ynl:
+            op = ynl.rsp_by_value[msg.cmd()]
+            fixed_header_size = ynl._fixed_header_size(op)
+        msg.raw_attrs = NlAttrs(msg.raw[fixed_header_size:])
+        return msg
+
+    def get_mcast_id(self, mcast_name, mcast_groups):
+        if mcast_name not in mcast_groups:
+            raise Exception(f'Multicast group "{mcast_name}" not present in the spec')
+        return mcast_groups[mcast_name].value
+
+
+class GenlProtocol(NetlinkProtocol):
+    def __init__(self, family_name):
+        super().__init__(family_name, Netlink.NETLINK_GENERIC)
 
         global genl_family_name_to_id
         if genl_family_name_to_id is None:
@@ -354,6 +384,19 @@ class GenlFamily:
         self.genl_family = genl_family_name_to_id[family_name]
         self.family_id = genl_family_name_to_id[family_name]['id']
 
+    def message(self, flags, command, version, seq=None):
+        nlmsg = self._message(self.family_id, flags, seq)
+        genlmsg = struct.pack("BBH", command, version, 0)
+        return nlmsg + genlmsg
+
+    def _decode(self, nl_msg):
+        return GenlMsg(nl_msg)
+
+    def get_mcast_id(self, mcast_name, mcast_groups):
+        if mcast_name not in self.genl_family['mcast']:
+            raise Exception(f'Multicast group "{mcast_name}" not present in the family')
+        return self.genl_family['mcast'][mcast_name]
+
 
 #
 # YNL implementation details.
@@ -366,9 +409,19 @@ class YnlFamily(SpecFamily):
 
         self.include_raw = False
 
-        self.sock = socket.socket(socket.AF_NETLINK, socket.SOCK_RAW, Netlink.NETLINK_GENERIC)
+        try:
+            if self.proto == "netlink-raw":
+                self.nlproto = NetlinkProtocol(self.yaml['name'],
+                                               self.yaml['protonum'])
+            else:
+                self.nlproto = GenlProtocol(self.yaml['name'])
+        except KeyError:
+            raise Exception(f"Family '{self.yaml['name']}' not supported by the kernel")
+
+        self.sock = socket.socket(socket.AF_NETLINK, socket.SOCK_RAW, self.nlproto.proto_num)
         self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_CAP_ACK, 1)
         self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_EXT_ACK, 1)
+        self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_GET_STRICT_CHK, 1)
 
         self.async_msg_ids = set()
         self.async_msg_queue = []
@@ -381,18 +434,12 @@ class YnlFamily(SpecFamily):
             bound_f = functools.partial(self._op, op_name)
             setattr(self, op.ident_name, bound_f)
 
-        try:
-            self.family = GenlFamily(self.yaml['name'])
-        except KeyError:
-            raise Exception(f"Family '{self.yaml['name']}' not supported by the kernel")
 
     def ntf_subscribe(self, mcast_name):
-        if mcast_name not in self.family.genl_family['mcast']:
-            raise Exception(f'Multicast group "{mcast_name}" not present in the family')
-
+        mcast_id = self.nlproto.get_mcast_id(mcast_name, self.mcast_groups)
         self.sock.bind((0, 0))
         self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_ADD_MEMBERSHIP,
-                             self.family.genl_family['mcast'][mcast_name])
+                             mcast_id)
 
     def _add_attr(self, space, name, value):
         try:
@@ -454,6 +501,17 @@ class YnlFamily(SpecFamily):
                 decoded = NlAttr.formatted_string(decoded, attr_spec.display_hint)
         return decoded
 
+    def _decode_array_nest(self, attr, attr_spec):
+        decoded = []
+        offset = 0
+        while offset < len(attr.raw):
+            item = NlAttr(attr.raw, offset)
+            offset += item.full_len
+
+            subattrs = self._decode(NlAttrs(item.raw), attr_spec['nested-attributes'])
+            decoded.append({ item.type: subattrs })
+        return decoded
+
     def _decode(self, attrs, space):
         attr_space = self.attr_sets[space]
         rsp = dict()
@@ -473,6 +531,8 @@ class YnlFamily(SpecFamily):
                 decoded = True
             elif attr_spec["type"] in NlAttr.type_formats:
                 decoded = attr.as_scalar(attr_spec['type'], attr_spec.byte_order)
+            elif attr_spec["type"] == 'array-nest':
+                decoded = self._decode_array_nest(attr, attr_spec)
             else:
                 raise Exception(f'Unknown {attr_spec["type"]} with name {attr_spec["name"]}')
 
@@ -514,25 +574,53 @@ class YnlFamily(SpecFamily):
 
         return None
 
-    def _decode_extack(self, request, attr_space, extack):
+    def _decode_extack(self, request, op, extack):
         if 'bad-attr-offs' not in extack:
             return
 
-        genl_req = GenlMsg(NlMsg(request, 0, attr_space=attr_space))
-        path = self._decode_extack_path(genl_req.raw_attrs, attr_space,
-                                        20, extack['bad-attr-offs'])
+        msg = self.nlproto.decode(self, NlMsg(request, 0, op.attr_set))
+        offset = 20 + self._fixed_header_size(op)
+        path = self._decode_extack_path(msg.raw_attrs, op.attr_set, offset,
+                                        extack['bad-attr-offs'])
         if path:
             del extack['bad-attr-offs']
             extack['bad-attr'] = path
 
-    def handle_ntf(self, nl_msg, genl_msg):
+    def _fixed_header_size(self, op):
+        if op.fixed_header:
+            fixed_header_members = self.consts[op.fixed_header].members
+            size = 0
+            for m in fixed_header_members:
+                format = NlAttr.get_format(m.type, m.byte_order)
+                size += format.size
+            return size
+        else:
+            return 0
+
+    def _decode_fixed_header(self, msg, name):
+        fixed_header_members = self.consts[name].members
+        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(msg.raw, offset)
+            offset += format.size
+            if m.enum:
+                value = self._decode_enum(value, m)
+            fixed_header_attrs[m.name] = value
+        return fixed_header_attrs
+
+    def handle_ntf(self, decoded):
         msg = dict()
         if self.include_raw:
-            msg['nlmsg'] = nl_msg
-            msg['genlmsg'] = genl_msg
-        op = self.rsp_by_value[genl_msg.genl_cmd]
+            msg['raw'] = decoded
+        op = self.rsp_by_value[decoded.cmd()]
+        attrs = self._decode(decoded.raw_attrs, op.attr_set.name)
+        if op.fixed_header:
+            attrs.update(self._decode_fixed_header(decoded, op.fixed_header))
+
         msg['name'] = op['name']
-        msg['msg'] = self._decode(genl_msg.raw_attrs, op.attr_set.name)
+        msg['msg'] = attrs
         self.async_msg_queue.append(msg)
 
     def check_ntf(self):
@@ -552,12 +640,12 @@ class YnlFamily(SpecFamily):
                     print("Netlink done while checking for ntf!?")
                     continue
 
-                gm = GenlMsg(nl_msg)
-                if gm.genl_cmd not in self.async_msg_ids:
-                    print("Unexpected msg id done while checking for ntf", gm)
+                decoded = self.nlproto.decode(self, nl_msg)
+                if decoded.cmd() not in self.async_msg_ids:
+                    print("Unexpected msg id done while checking for ntf", decoded)
                     continue
 
-                self.handle_ntf(nl_msg, gm)
+                self.handle_ntf(decoded)
 
     def operation_do_attributes(self, name):
       """
@@ -570,15 +658,17 @@ class YnlFamily(SpecFamily):
 
       return op['do']['request']['attributes'].copy()
 
-    def _op(self, method, vals, dump=False):
+    def _op(self, method, vals, flags, dump=False):
         op = self.ops[method]
 
         nl_flags = Netlink.NLM_F_REQUEST | Netlink.NLM_F_ACK
+        for flag in flags or []:
+            nl_flags |= flag
         if dump:
             nl_flags |= Netlink.NLM_F_DUMP
 
         req_seq = random.randint(1024, 65535)
-        msg = _genl_msg(self.family.family_id, nl_flags, op.req_value, 1, req_seq)
+        msg = self.nlproto.message(nl_flags, op.req_value, 1, req_seq)
         fixed_header_members = []
         if op.fixed_header:
             fixed_header_members = self.consts[op.fixed_header].members
@@ -599,7 +689,7 @@ class YnlFamily(SpecFamily):
             nms = NlMsgs(reply, attr_space=op.attr_set)
             for nl_msg in nms:
                 if nl_msg.extack:
-                    self._decode_extack(msg, op.attr_set, nl_msg.extack)
+                    self._decode_extack(msg, op, nl_msg.extack)
 
                 if nl_msg.error:
                     raise NlError(nl_msg)
@@ -610,18 +700,20 @@ class YnlFamily(SpecFamily):
                     done = True
                     break
 
-                gm = GenlMsg(nl_msg, fixed_header_members)
+                decoded = self.nlproto.decode(self, nl_msg)
+
                 # Check if this is a reply to our request
-                if nl_msg.nl_seq != req_seq or gm.genl_cmd != op.rsp_value:
-                    if gm.genl_cmd in self.async_msg_ids:
-                        self.handle_ntf(nl_msg, gm)
+                if nl_msg.nl_seq != req_seq or decoded.cmd() != op.rsp_value:
+                    if decoded.cmd() in self.async_msg_ids:
+                        self.handle_ntf(decoded)
                         continue
                     else:
-                        print('Unexpected message: ' + repr(gm))
+                        print('Unexpected message: ' + repr(decoded))
                         continue
 
-                rsp_msg = self._decode(gm.raw_attrs, op.attr_set.name)
-                rsp_msg.update(gm.fixed_header_attrs)
+                rsp_msg = self._decode(decoded.raw_attrs, op.attr_set.name)
+                if op.fixed_header:
+                    rsp_msg.update(self._decode_fixed_header(decoded, op.fixed_header))
                 rsp.append(rsp_msg)
 
         if not rsp:
@@ -630,8 +722,8 @@ class YnlFamily(SpecFamily):
             return rsp[0]
         return rsp
 
-    def do(self, method, vals):
-        return self._op(method, vals)
+    def do(self, method, vals, flags):
+        return self._op(method, vals, flags)
 
     def dump(self, method, vals):
-        return self._op(method, vals, dump=True)
+        return self._op(method, vals, [], dump=True)