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Subject: [Phrack] Building Into The Linux Network Layer

Description
"OTP (Obscure Transport Protocol): The first one is really simple (and fun too), it works in a client-server paradigm, meaning that you need to have two modules loaded, one on the client and one on the server (duh). The client module catches every TCP packet with the SYN flag on and swaps it with a FIN flag. The server module does exactly the opposite, swaps the FIN for a SYN. I find this particularly fun since both sides behave like a regular connection is undergoing, but if you watch it on the wire it will seem totally absurd. This can also do the same for ports and source address. Let's look at an example taken right from the wire."
--- From [Phrack] Building Into The Linux Network Layer

Objective: modify the code for kernel version 2.6.26

Code

Notes
1. Re: Change In sk_buff structure in 2.6.22 kernel

sk_buff *skb;

//Access tcp header
tcp_hdr(skb)

//Access ip header
ip_hdr(skb)

2. [PATCH 13/16] net: Make the device list and device lookups per namespace.

char *name = "eth0";
struct net_device *d;
d = get_dev_by_name(&init_net, name);