Subject: Re: [PATCH net-next] doc/netlink/specs: Add vlan attr in rt_link spec

From: Donald Hunter <[email-masked]>
Date: Fri, 08 Mar 2024 13:05:45 +0000

Hangbin Liu <[email-masked]> writes:

> With command:
>  # ./tools/net/ynl/cli.py \
>  --spec Documentation/netlink/specs/rt_link.yaml \
>  --do getlink --json '{"ifname": "eno1.2"}'
>
> Before:
> Exception: No message format for 'vlan' in sub-message spec 'linkinfo-data-msg'
>
> After:
>  'linkinfo': {'data': {'flag': {'flags': {'bridge-binding',
>                                           'gvrp',
>                                           'reorder-hdr'},
>                                 'mask': 4294967295},
>                        'id': 2,
>                        'protocol': 129},
>               'kind': 'vlan'},
>
> Signed-off-by: Hangbin Liu <[email-masked]>
> ---
> Not sure if there is a proper way to show the mask and protocol

Using display-hint, e.g. display-hint: hex, is intended to tell the ynl
cli to render output in a human readable way. Unfortunately it currently
only works for binary attributes.

It can be done like this:

      -
        name: mask
        type: binary
        len: 4
        display-hint: hex

./tools/net/ynl/cli.py \
--spec Documentation/netlink/specs/rt_link.yaml \
--do getlink --json '{"ifname": "wlan0.8"}' --output-json | jq -C '.linkinfo'
{
  "kind": "vlan",
  "data": {
    "protocol": 33024,
    "id": 8,
    "flag": {
      "flags": [
        "reorder-hdr"
      ],
      "mask": "ff ff ff ff"
    }
  }
}

But it seems wrong to change the struct definition for this. We should
patch ynl to support hex rendering of integers.

For the protocol, you'd need to add an enum of ethernet protocol
numbers, from the info in include/uapi/linux/if_ether.h

> +  -
> +    name: linkinfo-vlan-attrs
> +    name-prefix: ifla-vlan-
> +    attributes:
> +      -
> +        name: id
> +        type: u16
> +      -
> +        name: flag
> +        type: binary
> +        struct: ifla-vlan-flags
> +      -
> +        name: egress-qos
> +        type: nest
> +        nested-attributes: ifla-vlan-qos
> +      -
> +        name: ingress-qos
> +        type: nest
> +        nested-attributes: ifla-vlan-qos
> +      -
> +        name: protocol
> +        type: u16

The protocol value is in big endian format, so it is actually 33024
(0x8100) not 129. You need to add byte-order: big-endian

> +  -
> +    name: ifla-vlan-qos
> +    name-prefix: ifla-vlan-qos
> +    attributes:
> +      -
> +        name: mapping
> +        type: binary
> +        struct: ifla-vlan-qos-mapping
>    -
>      name: linkinfo-vrf-attrs
>      name-prefix: ifla-vrf-
> @@ -1666,6 +1732,9 @@ sub-messages:
>        -
>          value: tun
>          attribute-set: linkinfo-tun-attrs
> +      -
> +        value: vlan
> +        attribute-set: linkinfo-vlan-attrs
>        -
>          value: vrf
>          attribute-set: linkinfo-vrf-attrs