> On 20. Mar 2023, at 07:24, Zhenlei Huang <[email protected]> wrote:
> 
> 
> 
>> On Mar 20, 2023, at 1:35 AM, [email protected] wrote:
>> 
>>> On 19. Mar 2023, at 16:59, Marek Zarychta <[email protected]> 
>>> wrote:
>>> 
>>> W dniu 19.03.2023 o 14:42, [email protected] pisze:
>>>>> On 19. Mar 2023, at 14:12, Marek Zarychta <[email protected]> 
>>>>> wrote:
>>>>> 
>>>>> Dear subscribers of the list,
>>>>> 
>>>>> TCP algo modules can be loaded/unloaded/changed on the fly. In FreeBSD 
>>>>> 14-CURRENT one can even change it on an active socket with tcpsso(8) 
>>>>> utility, but there is no way to run jail with different TCP stack. 
>>>>> Neither normal nor VNET jail support switching sysctl 
>>>>> net.inet.tcp.functions_default.
>>>>> 
>>>>> Is there any way to set TCP algo inherited through fork+exec in a similar 
>>>>> way setfib(1) assigns fib or perhaps assign TCP algo per VNET instance?
>>>> Hi Marek,
>>>> 
>>>> so you are asking for the sysctl variable net.inet.tcp.functions_default 
>>>> to be vnet specific?
>>> 
>>> Thanks for the reply Michael,
>>> 
>>> yes, and... not. I tend to run non-vnet jails when it's possible, so in my 
>>> case, a jail(8) parameter like exec.fib would fit better, and even an 
>>> execute helper utility, a counterpart of setfib(1) would suffice.
>> Im not familiar with fibs, but the TCP stack knows about the vnet, so the 
>> handling of the stack can
>> be made vnet specific in the same way the handling of the CC module is.
> 
> 
> A quick look at tcp_subr.c, I think it is doable and make `tcp_func_set_ptr` 
> a per vnet one will be flexible enough.
Yes, but we must take regarding ref counting when trying to unload a module. 
But that
can be done similar to the handling of CC modules.
> 
>> But I'm not sure about fibs.
>> I can bring this up on the next FreeBSD transport VC and see what others 
>> think.
> 
> As for fibs, they stand for 'forwarding information base' and are for the 
> routing part.
> I do not think it is a proper hook point for upper layers such as TCP in this 
> context.
Yes, this is what I also think. Will bring it up on the transport call coming 
Thursday.

Best regards
Michael
> 
> Best regards,
> Zhenlei
> 
>> 
>> Best regards
>> Michael
>>> 
>>> With kind regards
>>> 
>>> Marek
>>> 
>>>> 
>>>> Best regards
>>>> Michael
>>>>> I am asking, since the almost perfect tcp_rack(4) applied on the host is 
>>>>> missing TCP-MD5 singing feature which is required in one of the jails.
>>>>> 
>>>>> Cheers
>>>>> -- 
>>>>> Marek Zarychta
> 
> 
> 
> 


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