Slipping in the window update

[silby at silby.com (Mike Silbersack)]

On Mon, 10 Jan 2005, Don Lewis wrote:

> Now that I've looked at the above case, it looks to me like your
> suggested patch might affect the response to a legitimate duplicate SYN.
> It will definitely follow a different code path.

You're right, I neglected to handle the duplicate SYN case.

Couldn't we centralize all SYN handling right after trimthenstep6:?

We could do something there like

if (th->th_seq != tp->irs) {
 	goto dropafterack; /* Or however we handle these bad syns */
} else {
thflags &= ~TH_SYN;
th->th_seq++;
if (th->th_urp > 1)
 	th->th_urp--;
else
 	thflags &= ~TH_URG;
todrop--;
}

And then we could tear out all the two places TH_SYN is mentioned below, 
the place I copied from, and the place where there the tcp_drop() is.

If we made that change, then we'd still be doing only one check for 
TH_SYN, but the code would be a lot easier to comprehend.

Mike "Silby" Silbersack