I am trying to modify skbuff data by skb_put() . that is happening successfully but probably using NF Hooks modifies the data at L3 and this ofcourse shall change the TCP checksum when receiver will compare the checksum at TCP header field and the one based on modified received data.

2. i have tried using csum_partial() and tcpudp_magic() but probably didnt understand the correct usage. so this didnt work for me. am i on the right path and if some one has gone through it can some one please guide the right path.

3. If you can guide please help out. the issue is at sender side .

thx a lot if some one can please help me . it is been over 20 days on the issue. i am new in this .