Re: PPPOE Was (Re: >=pre5 OOPS on boot failure to open /dev/console

From: Henner Eisen (eis@baty.hanse.de)
Date: Thu Apr 20 2000 - 13:59:53 EST


>>>>> "jamal" == jamal <hadi@cyberus.ca> writes:

    jamal> cc'ed now ;-> ) So how are you sending the feedback all the
    jamal> way to the transport protocol? Say, TCP where it might be

The trick is, I don't :-). Well, of course I do, but not directly
to tcp but only to the well-defined interface. The idea is to use the
same measure for local `congestion' as is also used to flow control socket
user-space applciations -- using the socket's wmem account. The outline
is as follows:

ppp->start_xmit() or dev->hard_start_xmit() first checks for the
lower layer if(socket sock_wspace(sk) == 0). If there is no write space,
then the frame is rejected.

Clearing a busy condition is done by hooking into the the sk->write_space()
callback. This needs to perform the same check as the xmit methods above,
and if successful, the busy conditions is cleared by netif_wake_queue() or
ppp_output_wakeup().

    jamal> really useful to distinguish between local congestion vs
    jamal> "somewhere along the end2end path" congestion; I havent
    jamal> looked at your code but i suspect you are using the

I hav'nt uploaded it yet because I have not done any testing yet. Hopefully,
in a few days I can do it.

Henner

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