# Re: \[RFC PATCH net-next\] rtnetlink: add RTNH\_F\_REJECT\_MASK

- From: Roopa Prabhu \<hidden\>
- Date: 2021-11-12 01:02:46 
- List: netdev
- Page: https://ratatoskr.run/netdev/2021/11/11215956
- Thread: https://ratatoskr.run/netdev/2021/11/11215934/t.md

```text

On 11/11/21 2:19 PM, David Ahern wrote:
> [ cc roopa]
>
> On 11/11/21 12:23 PM, Alexander Mikhalitsyn wrote:
>> On Thu, Nov 11, 2021 at 10:13 PM David Ahern [ref] wrote:
>>> On 11/11/21 9:02 AM, Alexander Mikhalitsyn wrote:
>>>> diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
>>>> index 5888492a5257..c15e591e5d25 100644
>>>> --- a/include/uapi/linux/rtnetlink.h
>>>> +++ b/include/uapi/linux/rtnetlink.h
>>>> @@ -417,6 +417,9 @@ struct rtnexthop {
>>>>   #define RTNH_COMPARE_MASK    (RTNH_F_DEAD | RTNH_F_LINKDOWN | \
>>>>                                 RTNH_F_OFFLOAD | RTNH_F_TRAP)
>>>>
>>>> +/* these flags can't be set by the userspace */
>>>> +#define RTNH_F_REJECT_MASK   (RTNH_F_DEAD | RTNH_F_LINKDOWN)
>>>> +
>>>>   /* Macros to handle hexthops */
>>> Userspace can not set any of the flags in RTNH_COMPARE_MASK.
>> Hi David,
>>
>> thanks! So, I have to prepare a patch which fixes current checks for rtnh_flags
>> against RTNH_COMPARE_MASK. So, there is no need to introduce a separate
>> RTNH_F_REJECT_MASK.
>> Am I right?
>>
> Added Roopa to double check if Cumulus relies on this for their switchd.
>
> If that answer is no, then there is no need for a new mask.
>

yes, these flags are already exposed to userspace and we do use it.

We have also considered optimizations where routing daemons set OFFLOAD and drivers clear it when offload fails.

I wont be surprised if other open network os distributions are also using it.


Thanks for the headsup David.

```