RE: [lwip-users] 0.7.1: Assert fails in tcp_process

[Chris Jones]

Tom,

I had a problem a few weeks ago with #s 2  & 3 below.

In my case, when porting the stack to the C55 DSP, I decided to implement
the timeouts as a seperate thread that was spawned and would sleep until it
was time to execute the callback function.

Well, after many hours of debug, I came to realize that the code in tcpin.c
and tcpout.c is not thread safe, therefore the unacked and unsent queues
were being changed asynchronously to the main tcp thread and it was screwing
things up.

I have since implemented the timeouts according to the porting guide and
things are working. Performance seems to be a dog right now, but I haven't
set about to find out wpslhat is wrong yet.

Hope this helps.

Chris Jones
Engenium Technologies


-----Original Message-----
From: address@hidden
[mailto:address@hidden Behalf
Of Tom C. Barker
Sent: Tuesday, March 09, 2004 7:20 PM
To: 'Mailing list for lwIP users'
Subject: [lwip-users] 0.7.1: Assert fails in tcp_process


Hello,

Could anyone explain why I might consistently be getting any one of
the following failing ASSERTs?

( I would think someone has run into these issues or the ASSERTs
would never have been added.)

Thanks,
Tom

(1) In tcp.c, tcp_slowtmr(), it will fail on pcb->state != TIME_WAIT.

 while (pcb != NULL) {
    LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: processing active pcb\n"));
    LWIP_ASSERT("tcp_slowtmr: active pcb->state != CLOSED\n", pcb->state !=
CLOSED);
    LWIP_ASSERT("tcp_slowtmr: active pcb->state != LISTEN\n", pcb->state !=
LISTEN);
    LWIP_ASSERT("tcp_slowtmr: active pcb->state != TIME-WAIT\n", pcb->state
!= TIME_WAIT);


(2) In tcpin.c, tcp_receive(), it will fail on ( pcb->unacked != NULL ||
pcb->unsent != NULL )

LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%u (after freeing unacked)\n", (unsigned
int)pcb->snd_queuelen));
  if (pcb->snd_queuelen != 0) {
    LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL ||
     pcb->unsent != NULL);
  }


(3) In tcpout.c, tcp_enqueue(), it will fail on ( pcb->unacked != NULL ||
pcb->unsent != NULL )
  if (pcb->snd_queuelen != 0) {
    LWIP_ASSERT("tcp_enqueue: valid queue length", pcb->unacked != NULL ||
    pcb->unsent != NULL);
  }



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