Re: [PATCH net-next 3/3] tools: ynl: add encoding support for 'sub-message' to ynl

[Donald Hunter <donald.hunter@gmail.com>]

Alessandro Marcolini <alessandromarcolini99@gmail.com> writes:

> Add encoding support for 'sub-message' attribute and for resolving
> sub-message selectors at different nesting level from the key
> attribute.

I think the relevant patches in my series are:

https://lore.kernel.org/netdev/20240123160538.172-3-donald.hunter@gmail.com/T/#u
https://lore.kernel.org/netdev/20240123160538.172-5-donald.hunter@gmail.com/T/#u

>
> Also, add encoding support for multi-attr attributes.

This would be better as a separate patch since it is unrelated to the
other changes.

> Signed-off-by: Alessandro Marcolini <alessandromarcolini99@gmail.com>
> ---
>  tools/net/ynl/lib/ynl.py | 54 +++++++++++++++++++++++++++++++++++-----
>  1 file changed, 48 insertions(+), 6 deletions(-)
>
> diff --git a/tools/net/ynl/lib/ynl.py b/tools/net/ynl/lib/ynl.py
> index 1e10512b2117..f8c56944f7e7 100644
> --- a/tools/net/ynl/lib/ynl.py
> +++ b/tools/net/ynl/lib/ynl.py
> @@ -449,7 +449,7 @@ class YnlFamily(SpecFamily):
>          self.sock.setsockopt(Netlink.SOL_NETLINK, Netlink.NETLINK_ADD_MEMBERSHIP,
>                               mcast_id)
>  
> -    def _add_attr(self, space, name, value):
> +    def _add_attr(self, space, name, value, vals):
>          try:
>              attr = self.attr_sets[space][name]
>          except KeyError:
> @@ -458,8 +458,13 @@ class YnlFamily(SpecFamily):
>          if attr["type"] == 'nest':
>              nl_type |= Netlink.NLA_F_NESTED
>              attr_payload = b''
> -            for subname, subvalue in value.items():
> -                attr_payload += self._add_attr(attr['nested-attributes'], subname, subvalue)
> +            # Check if it's a list of values (i.e. it contains multi-attr elements)
> +            for subname, subvalue in (
> +                ((k, v) for item in value for k, v in item.items())
> +                if isinstance(value, list)
> +                else value.items()
> +            ):
> +                attr_payload += self._add_attr(attr['nested-attributes'], subname, subvalue, vals)

Should really check whether multi-attr is true in the spec before
processing the json input as a list of values.

>          elif attr["type"] == 'flag':
>              attr_payload = b''
>          elif attr["type"] == 'string':
> @@ -481,6 +486,12 @@ class YnlFamily(SpecFamily):
>              attr_payload = format.pack(int(value))
>          elif attr['type'] in "bitfield32":
>              attr_payload = struct.pack("II", int(value["value"]), int(value["selector"]))
> +        elif attr['type'] == "sub-message":
> +            spec = self._resolve_selector(attr, vals)
> +            attr_spec = spec["attribute-set"]
> +            attr_payload = b''
> +            for subname, subvalue in value.items():
> +                attr_payload += self._add_attr(attr_spec, subname, subvalue, vals)
>          else:
>              raise Exception(f'Unknown type at {space} {name} {value} {attr["type"]}')
>  
> @@ -555,9 +566,40 @@ class YnlFamily(SpecFamily):
>          sub_msg_spec = self.sub_msgs[sub_msg]
>  
>          selector = attr_spec.selector
> -        if selector not in vals:
> +
> +        def _find_attr_path(attr, vals, path=None):
> +            if path is None:
> +                path = []
> +            if isinstance(vals, dict):
> +                if attr in vals:
> +                    return path
> +                for k, v in vals.items():
> +                    result = _find_attr_path(attr, v, path + [k])
> +                    if result is not None:
> +                        return result
> +            elif isinstance(vals, list):
> +                for idx, v in enumerate(vals):
> +                    result = _find_attr_path(attr, v, path + [idx])
> +                    if result is not None:
> +                        return result
> +            return None
> +
> +        def _find_selector_val(sel, vals, path):
> +            while path != []:
> +                v = vals.copy()
> +                for step in path:
> +                    v = v[step]
> +                if sel in v:
> +                    return v[sel]
> +                path.pop()
> +            return vals[sel] if sel in vals else None
> +
> +        attr_path = _find_attr_path(attr_spec.name, vals)
> +        value = _find_selector_val(selector, vals, attr_path)
> +
> +        if value is None:
>              raise Exception(f"There is no value for {selector} to resolve '{attr_spec.name}'")
> -        value = vals[selector]
> +
>          if value not in sub_msg_spec.formats:
>              raise Exception(f"No message format for '{value}' in sub-message spec '{sub_msg}'")
>  
> @@ -772,7 +814,7 @@ class YnlFamily(SpecFamily):
>                      format = NlAttr.get_format(m.type, m.byte_order)
>                      msg += format.pack(value)
>          for name, value in vals.items():
> -            msg += self._add_attr(op.attr_set.name, name, value)
> +            msg += self._add_attr(op.attr_set.name, name, value, vals)
>          msg = _genl_msg_finalize(msg)
>  
>          self.sock.send(msg, 0)