# touch vpn_centos6.sh
# chmod a+x vpn_centos6.sh

#!/bin/bash

function installVPN(){
    echo "begin to install VPN services";
    #check wether vps suppot ppp and tun
    
    yum remove -y pptpd ppp
    iptables --flush POSTROUTING --table nat
    iptables --flush FORWARD
    rm -rf /etc/pptpd.conf
    rm -rf /etc/ppp
    
    arch=`uname -m`
    
    wget http://www.hi-vps.com/downloads/dkms-2.0.17.5-1.noarch.rpm
    wget http://wty.name/linux/sources/kernel_ppp_mppe-1.0.2-3dkms.noarch.rpm
    wget http://www.hi-vps.com/downloads/kernel_ppp_mppe-1.0.2-3dkms.noarch.rpm
    wget http://www.hi-vps.com/downloads/pptpd-1.3.4-2.el6.$arch.rpm
    wget http://www.hi-vps.com/downloads/ppp-2.4.5-17.0.rhel6.$arch.rpm


    yum -y install make libpcap iptables gcc-c++ logrotate tar cpio perl pam tcp_wrappers
    rpm -ivh dkms-2.0.17.5-1.noarch.rpm
    rpm -ivh kernel_ppp_mppe-1.0.2-3dkms.noarch.rpm
    rpm -qa kernel_ppp_mppe
    rpm -Uvh ppp-2.4.5-17.0.rhel6.$arch.rpm    
    rpm -ivh pptpd-1.3.4-2.el6.$arch.rpm

    mknod /dev/ppp c 108 0 
    echo 1 > /proc/sys/net/ipv4/ip_forward 
    echo "mknod /dev/ppp c 108 0" >> /etc/rc.local
    echo "echo 1 > /proc/sys/net/ipv4/ip_forward" >> /etc/rc.local
    echo "localip 172.16.36.1" >> /etc/pptpd.conf
    echo "remoteip 172.16.36.2-254" >> /etc/pptpd.conf
    echo "ms-dns 8.8.8.8" >> /etc/ppp/options.pptpd
    echo "ms-dns 8.8.4.4" >> /etc/ppp/options.pptpd

    pass=`openssl rand 6 -base64`
    if [ "$1" != "" ]
    then pass=$1
    fi

    echo "vpn pptpd ${pass} *" >> /etc/ppp/chap-secrets

    iptables -t nat -A POSTROUTING -s 172.16.36.0/24 -j SNAT --to-source `ifconfig  | grep 'inet addr:'| grep -v '127.0.0.1' | cut -d: -f2 | awk 'NR==1 { print $1}'`
    iptables -A FORWARD -p tcp --syn -s 172.16.36.0/24 -j TCPMSS --set-mss 1356
    service iptables save

    chkconfig iptables on
    chkconfig pptpd on

    service iptables start
    service pptpd start

    echo "VPN service is installed, your VPN username is vpn, VPN password is ${pass}"
    
}

function repaireVPN(){
    echo "begin to repaire VPN";
    mknod /dev/ppp c 108 0
    service iptables restart
    service pptpd start
}

function addVPNuser(){
    echo "input user name:"
    read username
    echo "input password:"
    read userpassword
    echo "${username} pptpd ${userpassword} *" >> /etc/ppp/chap-secrets
    service iptables restart
    service pptpd start
}

echo "which do you want to?input the number."
echo "1. install VPN service"
echo "2. repaire VPN service"
echo "3. add VPN user"
read num

case "$num" in
[1] ) (installVPN);;
[2] ) (repaireVPN);;
[3] ) (addVPNuser);;
*) echo "nothing,exit";;
esac

# bash vpn_centos6.sh