Re: [PATCH net-next v2] ipv6: add IFLA_INET6_RA_MTU to expose mtu value in the RA message

[David Ahern]

On 8/2/21 6:40 AM, Rocco Yue wrote:
> On Sat, 2021-07-31 at 11:17 -0600, David Ahern wrote:
> On 7/30/21 7:52 PM, Rocco Yue wrote:
> 
>> IFLA_INET6_RA_MTU set. You can set "reject_message" in the policy to
>> return a message that "IFLA_INET6_RA_MTU can not be set".
> 
> Hi David,
> 
> Regarding setting "reject_message" in the policy, after reviewing
> the code, I fell that it is unnecessary, because the cost of
> implementing it seems to be a bit high, which requires modifying
> the function interface. The reasons is as follows:

The policy can be setup now to do the right thing once the extack
argument is available.

do_setlink() has an extack argument. It calls validate_linkmsg which
calls validate_link_af meaning support can be added in a single patch.
If you decide to do it, then it should be a separate patch preceding
this one.