RE: TCP stack behaviour question

From: Stuart MacDonald
Date: Mon Sep 18 2006 - 13:02:48 EST


From: Michael Kerrisk [mailto:mtk-manpages@xxxxxxx]
> Von: Andi Kleen <ak@xxxxxxx>
> > On Monday 18 September 2006 16:19, Stuart MacDonald wrote:
> > > From: Andi Kleen [mailto:ak@xxxxxxx]
> > > > > # man 7 ip
> > > > > ..
> > > > > Note that TCP has no error queue;
> MSG_ERRQUEUE is
> > > > > illegal on SOCK_STREAM sockets. Thus all errors are
> returned by
> > > > > socket function return or SO_ERROR only.
> > > > >
> > > > > Maybe the man page is wrong? That's from my FC 3 install.
> > > >
> > > > The sentence is correct, but TCP has a IP_RECVERR that works
> > > > differently without a queue. Basically it doesn't delay
> the error
> > > > reporting for incoming ICMPs to the last retransmit, but reports
> > > > them immediately. This is documented in tcp(7)
> > >
> > > I read that too, but didn't know which one was correct,
> so I erred on
> > > the side of caution and believed ip(7).
> >
> > Ok maybe it's a bit misleading. Michael, you might want to clarify.
>
> Can some one of you propose a better text please?

Perhaps

Note that TCP has no error queue; MSG_ERRQUEUE is illegal on
SOCK_STREAM sockets. IP_RECVERR is valid for TCP, but all errors are
returned by socket function return or SO_ERROR only.

?

..Stu

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