[SOLVED] Calculate new tcp checksum

yaplej · 09-24-2009, 06:57 PM

Hey all,

I am trying to find how to calculate an entire new TCP checksum. My code now does not seem to be working correctly. Whenever a packet requires a TCP checksum it fails the TCP checksum.

I have found some other functions, but have not had much luck with any of them so far.

tcph: struct tcphdr
tcplen: skb->len - ip_hdrlen(skb)
iph: struct iphdr

Code:

tcph->check = 0;
tcph->check = tcp_v4_check(tcph, tcplen, 
           iph->saddr, 
           iph->daddr,
           csum_partial((char *)tcph, tcplen, 0));

yaplej · 09-25-2009, 11:27 AM

My problem actually was somewhere else not with the checksum calculation. That code actually works perfectly to calculate a new checksum.