***simple NAT Kernel Module***
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refer to: Gaurav Tungatkar

only for TCP

Description:
1.use pre-routing to change destination IP (DNAT)
2.use post-routing to change source IP (SNAT)
3.re-calculate tcp checksum 
 
Instructions to compile:
1. Go to project/ folder.
2. make

Instructions to run:
1. insmod project/knat.ko