Hi, I am not very familiar with Linux kernel internals. I am trying to write a simple netfilter hook but facing some issues and did not find any clear answer in available docs on packet filter or netfilter hacking. I am writing an experimental kernel module that will register a NF_IP_PRE_ROUTING hook. This hook will change the destination address of the IP header. After that I'll update the checksum of the IP header by calling ip_nat_cheat_check as it is done in manip_pkt. Do I need to update the TCP checksum as well (if it is a TCP packet) since the pseudo header of the packet has changed? If I need to do update the tcp checksum as well then why isn't it being done mainp_pkt after changing the source or destination IP address? I also want to do similar modification for IPv6 packets. For IPv4 I have seen that skb_ip_make_writable is being called before modifying the IPv4 headers. I did not find anything similar for IPv6. What is the logic I should follow for IPv6? Regards, Partha -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
