Re: git: 62d2dcafb7f3 - main - if_epair: delete mbuf tags

From: Kristof Provost <kp_at_FreeBSD.org>
Date: Thu, 28 Oct 2021 16:22:32 UTC 
On 28 Oct 2021, at 17:45, John Baldwin wrote:
> On 10/28/21 1:50 AM, Kristof Provost wrote:
>> The branch main has been updated by kp:
>>
>> URL: https://cgit.FreeBSD.org/src/commit/?id=62d2dcafb7f33fe8f47e9d5dd519d665f7af140e
>>
>> commit 62d2dcafb7f33fe8f47e9d5dd519d665f7af140e
>> Author:     Kristof Provost <kp@FreeBSD.org>
>> AuthorDate: 2021-10-26 07:57:56 +0000
>> Commit:     Kristof Provost <kp@FreeBSD.org>
>> CommitDate: 2021-10-28 08:41:16 +0000
>>
>>      if_epair: delete mbuf tags
>>          Remove all (non-persistent) tags when we transmit a packet. Real network
>>      interfaces do not carry any tags either, and leaving tags attached can
>>      produce unexpected results.
>>          Reviewed by:    bz, glebius
>>      MFC after:      3 weeks
>>      Sponsored by:   Rubicon Communications, LLC ("Netgate")
>>      Differential Revision:  https://reviews.freebsd.org/D32663
>
> Wireguard has similar functionality FWIW, so it might be worth exposing a generic
> "mb_free_tags".  Wireguard also tries to reset some other state like the status
> of checksum offload since it is moving mbufs between an ifnet and a socket.  Not
> sure if epair also needs to clear all the same things?
>
Something like https://reviews.freebsd.org/D32710 ?

I stuck with the ‘clear’ terminology to distinguish it from the existing free functions, and because the use case is slightly different.

Kristof