Subject: Re: [Lksctp-developers] Re: SCTP config 2.5.70(-bk)

From: Jon Grimm <[email-masked]>
Date: Tue, 03 Jun 2003 16:07:08 -0500

Hi Adrian,

	Sorry for a bit of delay... We are away at an SCTP Interoperability 
event.

Adrian Bunk wrote:
> On Mon, Jun 02, 2003 at 09:53:04AM +0200, Margit Schubert-While wrote:
> 
> 
>>CONFIG_IPV6_SCTP__   is always being set to "y" even though
>>not selected (CONFIG_IPV6 not set)
> 
> 
> First, this doesn't do any harm since CONFIG_IPV6_SCTP__ alone doensn't 
> result in anything getting compiled.
> 
> But besides, it seems a bit broken.
> 
> From net/sctp/Kconfig:
> 
> <--  snip  -->
> 
> ...
> 
> config IPV6_SCTP__
>         tristate
>         default y if IPV6=n
>         default IPV6 if IPV6
> 
> config IP_SCTP
>         tristate "The SCTP Protocol (EXPERIMENTAL)"
>         depends on IPV6_SCTP__
> ...
> 
> <--  snip  -->
> 
> 
> Semantically equivalent is the following for IPV6_SCTP__:
> 
> config IPV6_SCTP__
>         tristate
>         default y if IPV6=n || IPV6=y
> 	default m if IPV6=m
> 
> 
> If it was intended to disallow a static IP_SCTP with a modular IPV6 it 
> doesn't work: It's perfectly allowed to set IPV6=n and IP_SCTP=y and 
> later compile and install a modular IPV6 for the same kernel.
> 

Are you sure?  I vaguely remember one of the network structs having 
#ifdef'd fields for v6.   Consequently, if one compiles first without, 
but the tries later compiles/loads ipv6... bad things happen as the 
kernel has a different concept of what the sock is.

> 
> Could someone from the SCTP developers comment on the intentions behind 
> IPV6_SCTP__ ?
> 

Yes.  The intent was to at least discourage a configuration that will 
segfault.

Thanks,
jon

>>Margit
> cu
> Adrian