How to enable tcp bbr in FreeBSD???

[Randall Stewart]

I am thinking that this really needs to have
a deeper support in the transport.

I see that OOB is even in socket_dgram process and there
are comments in there that indicate it may be a problem.. I 
know UDP does not support it.

So I think what is needed here is

1) a new pru_method that at send/rcv it can query if PRUS_EOF <or> PRUS_OOB
   is supported.
2) For UDP either query would return false.
3) For TCP this would resolve to a stack specific query. For the 
   freebsd stack, it would return true for both, for Rack or BBR
   you would get True for PRUS_EOF and False for PRUS_OOB. This way
   you could capture an error in any case by adding a check at the
   top of send/recv and immediately return an error as appropriate.
4) I would also think like all pru methods, you get a default of true/true
   so that way I guess unix domain sockets would continue as they are (not
   sure if they support these or not I should probably look)


R

> On Apr 26, 2020, at 8:55 AM, Randall Stewart <rrs at netflix.com> wrote:
> 
> Sure..
> 
> I will take a look at it. 
> 
> R
> 
>> On Apr 26, 2020, at 8:51 AM, Michael Tuexen <Michael.Tuexen at macmic.franken.de> wrote:
>> 
>> 
>> 
>>> On 26. Apr 2020, at 13:34, Randall Stewart via freebsd-transport <freebsd-transport at freebsd.org> wrote:
>>> 
>>> I have pulled down the reproducers.. one thing to note
>>> is they are all rack (though it could be that the problems
>>> are also in BBR). And of course FreeBSD is behind NF in
>>> rack at least.
>>> 
>>> I need to work on getting things updated.. one thing Michael, 
>>> both Rack and BBR in NF have lost the OOB handling. Please do
>>> not commit any more changes to Rack .. since that work has already
>>> been done.
>> I understand that the support of MSG_OOB is gone, but if you want
>> to return an error to the user when he uses MSG_OOB, you need to
>> trigger this error in the protocol specific code.
>> 
>> I don't think we can return an error in all cases (also for the
>> default stack), since that would change existing behaviour.
>> 
>> I leave this up to you.
>> 
>> Best regards
>> Michael
>>> 
>>> R
>>> 
>>>> On Apr 26, 2020, at 7:28 AM, Randall Stewart <rrs at netflix.com> wrote:
>>>> 
>>>> This is actually the first I have heard of these bugs…
>>>> 
>>>> I will have look at them Mark.
>>>> 
>>>> R
>>>> 
>>>>> On Apr 24, 2020, at 10:23 AM, Mark Johnston <markj at freebsd.org> wrote:
>>>>> 
>>>>> On Fri, Apr 24, 2020 at 03:15:08PM +0100, Tom Jones wrote:
>>>>>> rrs at freebsd.org
>>>>>> Bcc: 
>>>>>> Subject: Re: How to enable tcp bbr in FreeBSD???
>>>>>> Reply-To: 
>>>>>> In-Reply-To: <6042155a-297b-d85e-1d64-24d93da329a2 at gmail.com>
>>>>>> 
>>>>>> 
>>>>>> ... snip ...
>>>>>>> 
>>>>>>> Maybe it is not ready for prime time, i do not know why it is not in the
>>>>>>> default build.
>>>>>>> Maybe ask the committer.
>>>>>>> 
>>>>>> 
>>>>>> I have added rrs@ in cc and the freebsd-transport list. 
>>>>>> 
>>>>>> Does anyone know if there are plans to enable alternate TCP stacks in
>>>>>> generic? 
>>>>>> 
>>>>>> Is there a stability point we need to hit first?
>>>>> 
>>>>> There are a couple of open bugs found by syzkaller (complete with
>>>>> reproducers) that appeared when I enabled the alternate TCP stacks:
>>>>> 
>>>>> https://syzkaller.appspot.com/bug?id=986b4cecd84439df9794bda1a45d9cf0f50356fe
>>>>> https://syzkaller.appspot.com/bug?id=048f650e99696f881872a285cef0e3b9bd4f4e25
>>>>> 
>>>>> I'd expect these to be fixed before providing the alternate stacks in
>>>>> GENERIC.
>>>>> _______________________________________________
>>>>> freebsd-transport at freebsd.org mailing list
>>>>> https://lists.freebsd.org/mailman/listinfo/freebsd-transport
>>>>> To unsubscribe, send any mail to "freebsd-transport-unsubscribe at freebsd.org"
>>>> 
>>>> ------
>>>> Randall Stewart
>>>> rrs at netflix.com
>>>> 
>>>> 
>>>> 
>>> 
>>> ------
>>> Randall Stewart
>>> rrs at netflix.com
>>> 
>>> 
>>> 
>>> _______________________________________________
>>> freebsd-transport at freebsd.org mailing list
>>> https://lists.freebsd.org/mailman/listinfo/freebsd-transport
>>> To unsubscribe, send any mail to "freebsd-transport-unsubscribe at freebsd.org"
> 
> ------
> Randall Stewart
> rrs at netflix.com
> 
> 
> 

------
Randall Stewart
rrs at netflix.com