On Tue, 20 Dec 2005 23:45:41 -0500 Phillip Susi psusi@cfl.rr.com wrote:
A correctly implemented TCP stack will keep sending packets as long as there is free space in the window. If the existing code refuses to send more packets because there is SOME unacknowledged data, but enough room in the window to send more, then it is broken.
The entire point of having a window is so that the sender can send multiple packets before the first is ACK'd. Are you sure that the existing code refuses to send even when the window should allow it? Or is the window just too small? If so, are you sure it came directly from the bsd stack? I can not believe that both are true.
Ge van Geldorp wrote:
Although I understand what's wrong, I have a bit of difficulty trying to figure out how to fix it. Attached is a proposed fix, which basically attacks the problem at the sending end by removing the check if the connection is idle or not. With that fix the loop.c program works as I expect and http://www.reactos.org loads in a much more reasonable 2-3 sec in ibrowser. The problem that I have with the fix is that it's a change in code we borrowed from the BSD stack. I can hardly imagine that a piece of software so heavily used as the BSD stack would have such a fundamental problem.
Any thoughts?
GvG
The problem is likely in our loopback pseudo adapter rather than the BSD code, I'd guess.
It actually doesn't come directly from BSD. It was first in oskit, in which some work was done to isolate a few parts of FreeBSD and simplify and generalize the buffer management code. If there's a mistake in the TCP implementation itself, I might have introduced it. Since the IP and TCP code had stuff that overlaps code we already had in tcpip.sys, I narrowed the scope of the BSD code to make the import more compact (and preserve as much original code as possible in ReactOS).