[uip-users] checksum calculation

[Rajesh N R]

Hi,
I am going through the uIP code.  In the uip.c file the IP header checksum 
is compared with 0xFFFF.

if(uip_ipchksum() != 0xffff) { /* Compute and check the IP header
       checksum. */
   UIP_STAT(++uip_stat.ip.drop);
   UIP_STAT(++uip_stat.ip.chkerr);
   UIP_LOG("ip: bad checksum.");
   goto drop;
 }

Here if the checksum is not equal to 0xffff, the packet is dropped.
That means the IP header checksum value is always 0xffff.

Please comment. I am not able to understand the concept.  Thanks a lot.


with regards,


Rajesh NR
CDAC-T


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