> 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.

> 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.

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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