Re: [l2tpns-devel] retransmit control packets not working?

[Daryl T. <Dar...@io...>]

Geoffrey D. Bennett wrote:

>> Gotta admit that the logic in that section makes me go a little
>> cross-eyed.  If the tunnel window size dropped to zero I could see
>> it skipping the retransmit without it updating the retry timers,
>> but that's just wild speculation on my part.  You could patch the
>> Control message log message to print the Window size, if it occurs
>> often enough.

> AFAICT, the tunnel window size (you are talking about
> tunnel[t].window, yes?)

Yes.

> is set when the tunnel is created and never changed.

Well, it's set to a default value, then set on reception of
rx window avp.  I don't know if there is any logic that
prevents that message from being processed while a tunnel
is already set up (e.g. changes window size after the
tuneel is up) - I'm not that au fait with the RFCs.

> When you say about skipping the retx without it updating the retry
> timers, are you talking about this bit of code:
> 
>                         // resend pending messages as timeout on reply
>                         if (tunnel[t].retry <= TIME)
>                         {
>                                 controlt *c = tunnel[t].controls;
>                                 uint8_t w = tunnel[t].window;
>                                 tunnel[t].try++; // another try
>                                 if (tunnel[t].try > 5)
>                                         tunnelkill(t, "Timeout on control message"); // game over
>                                 else
>                                         while (c && w--)
>                                         {
>                                                 tunnelsend(c->buf, c->length, t);
>                                                 c = c->next;
>                                         }
> 
>                                 t_actions++;
>                         }
> 
> ?

Yes.  In particular the "while (c && w--)" logic.  I take it from your
subsequent post that you were getting a window size with a multiple of
256?

> In my case, tunnel[t].controls is going to point to the one and only
> message that hasn't been acknowledged.  tunnel[t].window can't be 0.
> So I'm confused.

Must be some part of "wild speculation on my part" that was ambiguous ...

In response to your patch question, I post them to the tracker as well
to ensure they don't get mangled by the mailing list (I've seen references
to patches that the archive doesn't seem to preserve).


-- 
Regards,
  Daryl Tester, IOCANE Pty. Ltd.