# Re: \[PATCH net v2\] openvswitch: Fix mask generation for nested attributes.

- From: David Miller \<davem@davemloft.net\>
- Date: 2015-09-15 23:25:53 
- List: netdev
- Page: https://ratatoskr.run/netdev/2015/09/10996531
- Thread: https://ratatoskr.run/netdev/2015/09/10996409/t.md

```text
From: Jesse Gross <redacted>
Date: Fri, 11 Sep 2015 18:38:28 -0700

> Masks were added to OVS flows in a way that was backwards compatible
> with userspace programs that did not generate masks. As a result, it is
> possible that we may receive flows that do not have a mask and we need
> to synthesize one.
> 
> Generating a mask requires iterating over attributes and descending into
> nested attributes. For each level we need to know the size to generate the
> correct mask. We do this with a linked table of attribute types.
> 
> Although the logic to handle these nested attributes was there in concept,
> there are a number of bugs in practice. Examples include incomplete links
> between tables, variable length attributes being treated as nested and
> missing sanity checks.
> 
> Signed-off-by: Jesse Gross <redacted>
> ---
> v2: Fix whitespace errors.
>     Add check for unknown bytes in VXLAN extensions.
>     Factor out check for nested or variable attributes.

Applied, thanks.
```