[lwip-devel] Regarding the Fragmentaion issue in the ICMP

[Honnappa, Arun (IE10)]

Hi 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