#!/usr/bin/env bash
  
#設置環境變量
export PATH=$PATH:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
function kernel () {
echo "
#CTCDN系統優化參數
#關閉ipv6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
#決定檢查過期多久鄰居條目
net.ipv4.neigh.default.gc_stale_time=120
#使用arp_announce / arp_ignore解決ARP映射問題
net.ipv4.conf.default.arp_announce = 2
net.ipv4.conf.all.arp_announce=2
net.ipv4.conf.lo.arp_announce=2
# 避免放大攻擊
net.ipv4.icmp_echo_ignore_broadcasts = 1
# 開啟惡意icmp錯誤消息保護
net.ipv4.icmp_ignore_bogus_error_responses = 1
#關閉路由轉發
net.ipv4.ip_forward = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
#開啟反向路徑過濾
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1
#處理無源路由的包
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.default.accept_source_route = 0
#關閉sysrq功能
kernel.sysrq = 0
#core文件名中添加pid作為擴展名
kernel.core_uses_pid = 1
# 開啟SYN洪水攻擊保護
net.ipv4.tcp_syncookies = 1
#修改消息隊列長度
kernel.msgmnb = 65536
kernel.msgmax = 65536
#設置最大內存共享段大小bytes
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
#timewait的數量，默認180000
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
#每個網絡接口接收數據包的速率比內核處理這些包的速率快時，允許送到隊列的數據包的最大數目
net.core.netdev_max_backlog = 262144
#限制僅僅是為了防止簡單的DoS 攻擊
net.ipv4.tcp_max_orphans = 3276800
#未收到客戶端確認信息的連接請求的最大值
net.ipv4.tcp_max_syn_backlog = 262144
net.ipv4.tcp_timestamps = 0
#內核放棄建立連接之前發送SYNACK 包的數量
net.ipv4.tcp_synack_retries = 1
#內核放棄建立連接之前發送SYN 包的數量
net.ipv4.tcp_syn_retries = 1
#啟用timewait 快速回收
net.ipv4.tcp_tw_recycle = 1
#開啟重用。允許將TIME-WAIT sockets 重新用于新的TCP 連接
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_fin_timeout = 1
#當keepalive 起用的時候，TCP 發送keepalive 消息的頻度。缺省是2 小時
net.ipv4.tcp_keepalive_time = 1800
net.ipv4.tcp_keepalive_probes = 3
net.ipv4.tcp_keepalive_intvl = 15
#允許系統打開的端口范圍
net.ipv4.ip_local_port_range = 1024 65000
#修改防火墻表大小，默認65536
net.netfilter.nf_conntrack_max=655350
net.netfilter.nf_conntrack_tcp_timeout_established=1200
#以下2條是Docker優化選項
#net.bridge.bridge-nf-call-iptables = 1
#net.bridge.bridge-nf-call-ip6tables = 1
# 確保無人能修改路由表
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.default.accept_redirects = 0
net.ipv4.conf.all.secure_redirects = 0
net.ipv4.conf.default.secure_redirects = 0" >> /etc/sysctl.conf

#是否開啟路由轉發
read -r -p "是否開啟路由轉發? [y|n] " input
case $input in
    y)
   sed -i "s#net.ipv4.ip_forward = 0#net.ipv4.ip_forward = 1#g" /etc/sysctl.conf
   sed -i "s#net.ipv4.conf.all.send_redirects = 0#net.ipv4.conf.all.send_redirects = 1#g"  /etc/sysctl.conf
   sed -i "s#net.ipv4.conf.default.send_redirects = 0#net.ipv4.conf.default.send_redirects = 1#g" /etc/sysctl.conf
   sysctl -p
   echo "優化完成，程序退出"
   ;;
   n)
   sysctl -p
   echo "優化完成，程序退出"
   exit
   ;;
 esac
 }
  
#是否優化內核
 function openkernel () {
     read -r -p "是否優化內核? [y/n] " input
     case $input in
         y)
         kernel
         ;;
         n)
         echo "優化完成，程序退出"
         exit
         ;;
     esac
 }
         
#修改文件數限制
 function openfile () {
     read -r -p "是否修改打開文件數的限制? [y/n] " input
     case $input in
         y)
         echo -e "* soft nofile 1024000n* hard nofile 1024000nhive   - nofile 1024000nhive   - nproc  1024000" >> /etc/security/limits.conf
         openkernel
         ;;
         n)
         openkernel
         ;;
    esac
 }
  
#修改用戶進程限制
 function userlimits () {
     read -r -p "是否加大普通用戶限制? [y/n] " input
     case $input in
         y)
         sed -i 's#4096#65535#g'   /etc/security/limits.d/20-nproc.conf
         openfile
         ;;
         n)
         openfile
         ;;
     esac
 }      
  
#修改主機名
 function hostname () {
     read -r -p "是否要修改主機名? [y/n]" input
     case $input in
         y)
         read -r -p "請輸入主機名:" hostname
         hostnamectl set-hostname $hostname
         userlimits
         ;;
         n)
         userlimits
         ;;
     esac
 }
  
#基礎優化函數
 function All () {
     yum -y install epel-release
     yum update
     yum -y install net-tools tree lrzsz unzip telnet vim gcc cmake wget git ntpdate bash-completion
     sed -i "/^SElinux/s#enforcing#disabled#g" /etc/selinux/config
     cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
     echo -e "*/1 * * * * ntpdate ntp1.aliyun.com" > /var/spool/cron/root
     hostname
 }
   
 echo "--------------------------------------------------------------------"
 echo "本腳本可以根據需求選擇要優化的選項-只是針對剛剛安裝好的系統做優化,并且保證正常上網"
 echo "--------------------------------------------------------------------"
 echo "請選擇你要使用的選項:"
 echo "(0) 基本優化"
 echo "(9) Exit"
 echo "--------------------------------------------------------------------"
 read -p "請輸入選項編號>>>>:" input
   
 case $input in
     0)
     echo "-----------執行基本優化---------------"
     sleep 1
     All;;
     9)
     echo "-----------退出腳本---------------"
     exit;;
 esac