Re: [PATCH v1 2/2] TCPCT API sockopt update to draft -03

[Eric Dumazet <eric.dumazet@gmail.com>]

Le jeudi 13 janvier 2011 à 12:32 -0500, William Allen Simpson a écrit :
> On 1/12/11 1:56 PM, Stephen Hemminger wrote:
> > On Wed, 12 Jan 2011 12:59:38 -0500
> > William Allen Simpson<william.allen.simpson@gmail.com>  wrote:
> >
> >> diff --git a/include/linux/tcp.h b/include/linux/tcp.h
> >> index e64f4c6..c8f4017 100644
> >> --- a/include/linux/tcp.h
> >> +++ b/include/linux/tcp.h
> >> @@ -185,22 +185,37 @@ struct tcp_md5sig {
> >>   #define TCP_COOKIE_PAIR_SIZE	(2*TCP_COOKIE_MAX)
> >>
> >>   /* Flags for both getsockopt and setsockopt */
> >> -#define TCP_COOKIE_IN_ALWAYS	(1<<  0)	/* Discard SYN without cookie */
> >> -#define TCP_COOKIE_OUT_NEVER	(1<<  1)	/* Prohibit outgoing cookies,
> >> +#define TCPCT_IN_ALWAYS		(1<<  0)	/* Discard SYN without cookie */
> >> +#define TCPCT_OUT_NEVER		(1<<  1)	/* Prohibit outgoing cookies,
> >
> > You end up changing values in kernel userspace API in a way
> > that is incompatible with older applications. This is not acceptable.
> >
> While I agree in principle and argued strongly against it, other
> members of the research group (particularly the original project
> sponsor) have over-ridden my concerns.  I'm sorry to inform you that
> many/most participants don't care much about Linux.
> 

How leaving TCP_COOKIE_IN_ALWAYS and TCP_COOKIE_OUT_NEVER definitions so
that user space programs compiles can be a problem to "research group" ?

AFAIK, TCPCT_IN_ALWAYS / TCPCT_OUT_NEVER are not mentioned in
http://www.rfc-editor.org/authors/rfc6013.txt

But TCP_COOKIE_IN_ALWAYS and TCP_COOKIE_OUT_NEVER are ...

Isnt it a bit confusing ?

> Note that the *bits* are the same, and previously compiled programs
> (that don't access more advanced features) should continue to run as
> they have in the past.
> 
> Even though I'm not paid to work on Linux, I'm doing my best to give you
> folks a quick heads up and provide code to rectify the very recent changes
> that can be propagated back through the stable tree (to 2.6.33).
> 
> As always, what you actually do with my code is up to you....

Maybe its too early, and we should wait for an official RFC, especially
if you insist breaking API in 6 months.