[lwip-devel] Re: [bug #25940] Regarding the Fragmentation issue in the ICMP packet.

[arun kumar]

Hi Can any body .. answer me for this query that i have posted..

I have treied increasing the IP_REASS_MAX_PBUFS and the PBUF_POOL_SIZE but it didnt work out. It is always going to Assert statement in pbuf_header in pbuf.c at line

 

if (header_size_increment < 0){
    increment_magnitude = -header_size_increment;
    /* Check that we aren't going to move off the end of the pbuf */
    LWIP_ERROR("increment_magnitude <= p->len", (increment_magnitude <= p->len),  

    return 1;);
  }

 

Please do the need ful.

 

Thanks

On Fri, Mar 20, 2009 at 9:15 PM, Arun <address@hidden> wrote:

URL:
 <http://savannah.nongnu.org/bugs/?25940>

                Summary: Regarding the Fragmentation issue in the ICMP
packet.
                Project: lwIP - A Lightweight TCP/IP stack
           Submitted by: arun_rh
           Submitted on: Fri 20 Mar 2009 03:45:28 PM GMT
               Category: None
               Severity: 3 - Normal
             Item Group: Faulty Behaviour
                 Status: None
                Privacy: Public
            Assigned to: None
            Open/Closed: Open
        Discussion Lock: Any
        Planned Release:
           lwIP version: 1.3.0

   _______________________________________________________

Details:

Hello All,
Currently I am working on the LWIP stack, which we have ported on to the
STR912 processor.
Actually I am facing a strange problem of reassembling process of Fragmented
ICMP packet.
My observation was the ping utility is failing at higher packet size (more
than 1472 ) say1500.
But the same works if we send the ping command less than 1472.
So I understand that when ever we send the ping command with more than 1472
bytes, it basically splits the packet into and the same Is reassembled on the
LWIP stack. I saw the sender sends the ping command with fragmented messages.


These fragmented messages are received on the STR912 that is our target where
the LWIP stack will be running.

So the LWIP while in the process of reassembling it is going to some Assert
statement. Actually it is going to some assert statement in pbuf_header()
function in the pbuf.c file and the code is

if (header_size_increment < 0){

   increment_magnitude = -header_size_increment;

   /* Check that we aren't going to move off the end of the pbuf */

   LWIP_ERROR("increment_magnitude <= p->len", (increment_magnitude <=
p->len), return 1;);

 }

I have seen one of the mail asking the same question for the solution in
2006. So could u please suggest me whether the issue of reassembling process
and the fragmentation is fixed or not. Currently I am using the 1.0.3 version.
Does the LWIP stack is tested with the Ping utility with more than 10000 bytes
?


Thanks

With Regards

Arun Honnappa





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