irksome-turtle（其实是个vpn程序）

encrypted IPv4 in IPv4 tunnel.

The encryption code(encyrpt.c) will not be included due to security concern.

Usage:

    Local:
        sudo ./irksome -s  -d 
        sudo ./tun_setup.sh

    Remote:
        sudo ./irksome -s  -d 
        sudo ./tun_setup_peer.sh

Documents referred:

• TUN based: http://backreference.org/2010/03/26/tuntap-interface-tutorial/
• IP based, try to use one of these IP protocol ID: http://www.iana.org/assignments/protocol-numbers/protocol-numbers.txt

from https://github.com/cathay4t/irksome-turtle
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在 mac上，把项目clone下来后，
cd irksome-turtle
make
显示：
gcc    -c -o irksome.o irksome.c
irksome.c:33:10: fatal error: 'linux/if.h' file not found
#include
         ^
1 error generated. 

可见，客户端程序只能运行在linux桌面系统上。