#!/bin/bash

#set ulimit
function __set_ulimit(){
echo "ulimit -SHn 102400" >> /etc/rc.local

cat >> /etc/security/limits.conf << EOF
* soft nofile 65535
* hard nofile 65535
EOF
}

#set ntp
function __set_ntp(){
yum -y install ntp
echo "* 4 * * * /usr/sbin/ntpdate 114.80.81.13 > /dev/null 2>&1" >> /var/spool/cron/root
echo "ntp OK!"
}

#set vim
function __set_bashrc(){
sed -i "8i alias vi='vim'" /root/.bashrc
echo 'syntax on' > /root/.vimrc 
sed -i "9i alias n='netstat -tunlp'" /root/.bashrc
. /root/.bashrc
}

#set sysctl
function __set_sysctl(){
true > /etc/sysctl.conf
cat >> /etc/sysctl.conf << EOF
net.ipv4.ip_forward = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.default.accept_source_route = 0
kernel.sysrq = 0
kernel.core_uses_pid = 1
net.ipv4.tcp_syncookies = 1
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
net.ipv4.tcp_max_tw_buckets = 6000
net.ipv4.tcp_sack = 1
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_rmem = 4096 87380 4194304
net.ipv4.tcp_wmem = 4096 16384 4194304
net.core.wmem_default = 8388608
net.core.rmem_default = 8388608
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.core.netdev_max_backlog = 262144
net.core.somaxconn = 262144
net.ipv4.tcp_max_orphans = 3276800
net.ipv4.tcp_max_syn_backlog = 262144
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_synack_retries = 1
net.ipv4.tcp_syn_retries = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_fin_timeout = 1
net.ipv4.tcp_keepalive_time = 1200
net.ipv4.ip_local_port_range = 1024 65535
EOF

/sbin/sysctl -p
echo "sysctl set OK!"
}

#close ctrl+alt+del
function __close_cad(){
sed -i "s/ca::ctrlaltdel:\/sbin\/shutdown -t3 -r now/#ca::ctrlaltdel:\/sbin\/shutdown -t3 -r now/" /etc/inittab
}

#set purview
function __set_purview(){
chmod 600 /etc/passwd
chmod 600 /etc/shadow
chmod 600 /etc/group
chmod 600 /etc/gshadow
}

#disable ipv6
function __close_ipv6(){
echo "alias net-pf-10 off" >> /etc/modprobe.conf
echo "alias ipv6 off" >> /etc/modprobe.conf
/sbin/chkconfig --level 35 ip6tables off
echo "ipv6 is disabled!"
}
 
#disable selinux
function __close_selinux(){
sed -i '/SELINUX/s/enforcing/disabled/' /etc/selinux/config 
/usr/sbin/setenforce 0
echo "selinux is disable!"
}

#tunoff services
function __close_service(){
for i in `ls /etc/rc3.d/S*`
do
 CURSRV=`echo $i|cut -c 15-`
 echo $CURSRV
 case $CURSRV in
           crond | irqbalance | microcode_ctl | lvm2-monitor | network | random | sshd | syslog  )
       echo "Base services, Skip!"
       ;;
       *)
           echo "change $CURSRV to off"
           chkconfig --level 235 $CURSRV off
           service $CURSRV stop
       ;;
 esac
 done
 
echo "service is init is ok.............."
}

#ssh
function __set_ssh(){
sed -i 's/^GSSAPIAuthentication yes$/GSSAPIAuthentication no/' /etc/ssh/sshd_config
sed -i 's/^#UseDNS yes$/UseDNS no/' /etc/ssh/sshd_config
/sbin/service sshd restart
echo "ssh OK!"
}

#iptables
function __clean_iptables(){
/sbin/service iptables start
iptables -t nat -F
iptables -t nat -X
iptables -t nat -P PREROUTING ACCEPT
iptables -t nat -P POSTROUTING ACCEPT
iptables -t nat -P OUTPUT ACCEPT
iptables -t mangle -F
iptables -t mangle -X
iptables -t mangle -P PREROUTING ACCEPT
iptables -t mangle -P INPUT ACCEPT
iptables -t mangle -P FORWARD ACCEPT
iptables -t mangle -P OUTPUT ACCEPT
iptables -t mangle -P POSTROUTING ACCEPT
iptables -F
iptables -X
iptables -P FORWARD ACCEPT
iptables -P INPUT ACCEPT
iptables -P OUTPUT ACCEPT
iptables -t raw -F
iptables -t raw -X
iptables -t raw -P PREROUTING ACCEPT
iptables -t raw -P OUTPUT ACCEPT
/sbin/service iptables save
/sbin/chkconfig --level 35 iptables off
}

#set timeout
function __set_TMOUT(){
echo "TMOUT=300" >>/etc/profile
source /etc/profile
}

#Execution
__set_ulimit
__set_ntp
__set_bashrc
__set_sysctl
__close_cad
__set_purview
__close_ipv6
__close_selinux
__close_service
__set_ssh
__clean_iptables
__set_TMOUT