谷歌BBR拥塞算法内核更新

为什么想到这个呢，算法什么的又不太懂，这是 因为搭建VPN + BBR 与之简直绝配

有的人搭建SSR ，配一个什么锐速，还需要降内核版本， 而且还容易出错，降了之后更加容易出现兼容性问题，所以偶尔看到了google的BBR 拥塞阻塞算法

算法原理不知道，也不想去深究 。 原理 这篇博客 讲得还是很清楚的 ，可以一探

Google 开源了其 TCP BBR 拥塞控制算法，并提交到了 Linux 内核，从 4.9 开始，Linux 内核已经用上了该算法。根据谷歌的风格，Google 总是先在自家的生产环境上线运用后，才会将代码开源，此次也不例外。
根据大佬的实地测试，在部署了最新版内核并开启了 TCP BBR 的机器上，网速甚至可以提升好几个数量级。

根据某个大佬开发的一键安装的脚本，可以实现最新内核的安装和 TCP BBR 脚本
脚本如下：

 #!/usr/bin/env bash
 #
 # Auto install latest kernel for TCP BBR
 #
 # System Required:  CentOS +, Debian7+, Ubuntu12+
 #
 # Copyright (C) - Teddysun <i@teddysun.com>
 #
 # URL: https://teddysun.com/489.html
 #

 red='\033[0;31m'
 green='\033[0;32m'
 yellow='\033[0;33m'
 plain='\033[0m'

 cur_dir=$(pwd)

 [[ $EUID -ne  ]] && echo -e "${red}Error:${plain} This script must be run as root!" && exit 

 [[ -d "/proc/vz" ]] && echo -e "${red}Error:${plain} Your VPS is based on OpenVZ, which is not supported." && exit 

 if [ -f /etc/redhat-release ]; then
     release="centos"
 elif cat /etc/issue | grep -Eqi "debian"; then
     release="debian"
 elif cat /etc/issue | grep -Eqi "ubuntu"; then
     release="ubuntu"
 elif cat /etc/issue | grep -Eqi "centos|red hat|redhat"; then
     release="centos"
 elif cat /proc/version | grep -Eqi "debian"; then
     release="debian"
 elif cat /proc/version | grep -Eqi "ubuntu"; then
     release="ubuntu"
 elif cat /proc/version | grep -Eqi "centos|red hat|redhat"; then
     release="centos"
 else
     release=""
 fi

 is_digit(){
     local input=${}
     if [[ "$input" =~ ^[-]+$ ]]; then
         return
     else
         return
     fi
 }

 is_64bit(){
     if [ $(getconf WORD_BIT) = '' ] && [ $(getconf LONG_BIT) = '' ]; then
         return
     else
         return
     fi
 }

 get_valid_valname(){
     local val=${}
     local new_val=$(eval echo $val | sed 's/[-.]/_/g')
     echo ${new_val}
 }

 get_hint(){
     local val=${}
     local new_val=$(get_valid_valname $val)
     eval echo "\$hint_${new_val}"
 }

 #Display Memu
 display_menu(){
     local soft=${}
     local default=${}
     eval local arr=(\${${soft}_arr[@]})
     local default_prompt
     if [[ "$default" != "" ]]; then
         if [[ "$default" == "last" ]]; then
             default=${#arr[@]}
         fi
         default_prompt="(default ${arr[$default-1]})"
     fi
     local pick
     local hint
     local vname
     local prompt="which ${soft} you'd select ${default_prompt}: "

     while :
     do
         echo -e "\n------------ ${soft} setting ------------\n"
         for ((i=;i<=${#arr[@]};i++ )); do
             vname="$(get_valid_valname ${arr[$i-1]})"
             hint="$(get_hint $vname)"
             [[ "$hint" == "" ]] && hint="${arr[$i-1]}"
             echo -e "${green}${i}${plain}) $hint"
         done
         echo
         read -p "${prompt}" pick
         if [[ "$pick" == "" && "$default" != "" ]]; then
             pick=${default}
             break
         fi

         if ! is_digit "$pick"; then
             prompt="Input error, please input a number"
             continue
         fi

         if [[ "$pick" -lt  || "$pick" -gt ${#arr[@]} ]]; then
             prompt="Input error, please input a number between 1 and ${#arr[@]}: "
             continue
         fi

         break
     done

     eval ${soft}=${arr[$pick-]}
     vname="$(get_valid_valname ${arr[$pick-1]})"
     hint="$(get_hint $vname)"
     [[ "$hint" == "" ]] && hint="${arr[$pick-1]}"
     echo -e "\nyour selection: $hint\n"
 }

 version_ge(){
     test "$(echo "$@" | tr " " "\n" | sort -rV | head -n 1)" == "$1"
 }

 get_latest_version() {
     latest_version=($(wget -qO- https://kernel.ubuntu.com/~kernel-ppa/mainline/ | awk -F'\"v' '/v[4-9]./{print $2}' | cut -d/ -f1 | grep -v - | sort -V))

     [ ${#latest_version[@]} -eq  ] && echo -e "${red}Error:${plain} Get latest kernel version failed." && exit 

     kernel_arr=()
     for i in ${latest_version[@]}; do
         if version_ge $i 4.14; then
             kernel_arr+=($i);
         fi
     done

     display_menu kernel last

     if [[ `getconf WORD_BIT` == "" && `getconf LONG_BIT` == "" ]]; then
         deb_name=$(wget -qO- https://kernel.ubuntu.com/~kernel-ppa/mainline/v${kernel}/ | grep "linux-image" | grep "generic" | awk -F'\">' '/amd64.deb/{print $2}' | cut -d'<' -f1 | head -1)
         deb_kernel_url="https://kernel.ubuntu.com/~kernel-ppa/mainline/v${kernel}/${deb_name}"
         deb_kernel_name="linux-image-${kernel}-amd64.deb"
         modules_deb_name=$(wget -qO- https://kernel.ubuntu.com/~kernel-ppa/mainline/v${kernel}/ | grep "linux-modules" | grep "generic" | awk -F'\">' '/amd64.deb/{print $2}' | cut -d'<' -f1 | head -1)
         deb_kernel_modules_url="https://kernel.ubuntu.com/~kernel-ppa/mainline/v${kernel}/${modules_deb_name}"
         deb_kernel_modules_name="linux-modules-${kernel}-amd64.deb"
     else
         deb_name=$(wget -qO- https://kernel.ubuntu.com/~kernel-ppa/mainline/v${kernel}/ | grep "linux-image" | grep "generic" | awk -F'\">' '/i386.deb/{print $2}' | cut -d'<' -f1 | head -1)
         deb_kernel_url="https://kernel.ubuntu.com/~kernel-ppa/mainline/v${kernel}/${deb_name}"
         deb_kernel_name="linux-image-${kernel}-i386.deb"
         modules_deb_name=$(wget -qO- https://kernel.ubuntu.com/~kernel-ppa/mainline/v${kernel}/ | grep "linux-modules" | grep "generic" | awk -F'\">' '/i386.deb/{print $2}' | cut -d'<' -f1 | head -1)
         deb_kernel_modules_url="https://kernel.ubuntu.com/~kernel-ppa/mainline/v${kernel}/${modules_deb_name}"
         deb_kernel_modules_name="linux-modules-${kernel}-i386.deb"
     fi

     [ -z ${deb_name} ] && echo -e "${red}Error:${plain} Getting Linux kernel binary package name failed, maybe kernel build failed. Please choose other one and try again." && exit
 }

 get_opsy() {
     [ -f /etc/redhat-release ] && awk '{print ($1,$3~/^[0-9]/?$3:$4)}' /etc/redhat-release && return
     [ -f /etc/os-release ] && awk -F'[= "]' '/PRETTY_NAME/{print $3,$4,$5}' /etc/os-release && return
     [ -f /etc/lsb-release ] && awk -F'[="]+' '/DESCRIPTION/{print $2}' /etc/lsb-release && return
 }

 opsy=$( get_opsy )
 arch=$( uname -m )
 lbit=$( getconf LONG_BIT )
 kern=$( uname -r )

 get_char() {
     SAVEDSTTY=`stty -g`
     stty -echo
     stty cbreak
     dd if=/dev/tty bs= count= > /dev/null
     stty -raw
     stty echo
     stty $SAVEDSTTY
 }

 getversion() {
     if [[ -s /etc/redhat-release ]]; then
         grep -oE  "[0-9.]+" /etc/redhat-release
     else
         grep -oE  "[0-9.]+" /etc/issue
     fi
 }

 centosversion() {
     if [ x"${release}" == x"centos" ]; then
         local code=$
         local version="$(getversion)"
         local main_ver=${version%%.*}
         if [ "$main_ver" == "$code" ]; then
             return
         else
             return
         fi
     else
         return
     fi
 }

 check_bbr_status() {
     local param=$(sysctl net.ipv4.tcp_congestion_control | awk '{print $3}')
     if [[ x"${param}" == x"bbr" ]]; then
         return
     else
         return
     fi
 }

 check_kernel_version() {
     local kernel_version=$(uname -r | cut -d- -f1)
     if version_ge ${kernel_version} 4.9; then
         return
     else
         return
     fi
 }

 install_elrepo() {

     if centosversion ; then
         echo -e "${red}Error:${plain} not supported CentOS 5."
         exit
     fi

     rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org

     if centosversion ; then
         rpm -Uvh https://www.elrepo.org/elrepo-release-6-9.el6.elrepo.noarch.rpm
     elif centosversion ; then
         rpm -Uvh https://www.elrepo.org/elrepo-release-7.0-4.el7.elrepo.noarch.rpm
     fi

     if [ ! -f /etc/yum.repos.d/elrepo.repo ]; then
         echo -e "${red}Error:${plain} Install elrepo failed, please check it."
         exit
     fi
 }

 sysctl_config() {
     sed -i '/net.core.default_qdisc/d' /etc/sysctl.conf
     sed -i '/net.ipv4.tcp_congestion_control/d' /etc/sysctl.conf
     echo "net.core.default_qdisc = fq" >> /etc/sysctl.conf
     echo "net.ipv4.tcp_congestion_control = bbr" >> /etc/sysctl.conf
     sysctl -p >/dev/null >&
 }

 install_config() {
     if [[ x"${release}" == x"centos" ]]; then
         if centosversion ; then
             if [ ! -f "/boot/grub/grub.conf" ]; then
                 echo -e "${red}Error:${plain} /boot/grub/grub.conf not found, please check it."
                 exit
             fi
             sed -i 's/^default=.*/default=0/g' /boot/grub/grub.conf
         elif centosversion ; then
             if [ ! -f "/boot/grub2/grub.cfg" ]; then
                 echo -e "${red}Error:${plain} /boot/grub2/grub.cfg not found, please check it."
                 exit
             fi
             grub2-set-default
         fi
     elif [[ x"${release}" == x"debian" || x"${release}" == x"ubuntu" ]]; then
         /usr/sbin/update-grub
     fi
 }

 reboot_os() {
     echo
     echo -e "${green}Info:${plain} The system needs to reboot."
     read -p "Do you want to restart system? [y/n]" is_reboot
     if [[ ${is_reboot} == "y" || ${is_reboot} == "Y" ]]; then
         reboot
     else
         echo -e "${green}Info:${plain} Reboot has been canceled..."
         exit
     fi
 }

 install_bbr() {
     check_bbr_status
     if [ $? -eq  ]; then
         echo
         echo -e "${green}Info:${plain} TCP BBR has already been installed. nothing to do..."
         exit
     fi
     check_kernel_version
     if [ $? -eq  ]; then
         echo
         echo -e "${green}Info:${plain} Your kernel version is greater than 4.9, directly setting TCP BBR..."
         sysctl_config
         echo -e "${green}Info:${plain} Setting TCP BBR completed..."
         exit
     fi

     if [[ x"${release}" == x"centos" ]]; then
         install_elrepo
         [ ! "$(command -v yum-config-manager)" ] && yum install -y yum-utils > /dev/null >&
         [ x"$(yum-config-manager elrepo-kernel | grep -w enabled | awk '{print $3}')" != x"True" ] && yum-config-manager --enable elrepo-kernel > /dev/null >&
         if centosversion ; then
             if is_64bit; then
                 rpm_kernel_name="kernel-ml-4.18.20-1.el6.elrepo.x86_64.rpm"
                 rpm_kernel_devel_name="kernel-ml-devel-4.18.20-1.el6.elrepo.x86_64.rpm"
                 rpm_kernel_url_1="http://repos.lax.quadranet.com/elrepo/archive/kernel/el6/x86_64/RPMS/"
             else
                 rpm_kernel_name="kernel-ml-4.18.20-1.el6.elrepo.i686.rpm"
                 rpm_kernel_devel_name="kernel-ml-devel-4.18.20-1.el6.elrepo.i686.rpm"
                 rpm_kernel_url_1="http://repos.lax.quadranet.com/elrepo/archive/kernel/el6/i386/RPMS/"
             fi
             rpm_kernel_url_2="https://dl.lamp.sh/files/"
             wget -c -t3 -T60 -O ${rpm_kernel_name} ${rpm_kernel_url_1}${rpm_kernel_name}
             if [ $? -ne  ]; then
                 rm -rf ${rpm_kernel_name}
                 wget -c -t3 -T60 -O ${rpm_kernel_name} ${rpm_kernel_url_2}${rpm_kernel_name}
             fi
             wget -c -t3 -T60 -O ${rpm_kernel_devel_name} ${rpm_kernel_url_1}${rpm_kernel_devel_name}
             if [ $? -ne  ]; then
                 rm -rf ${rpm_kernel_devel_name}
                 wget -c -t3 -T60 -O ${rpm_kernel_devel_name} ${rpm_kernel_url_2}${rpm_kernel_devel_name}
             fi
             if [ -f "${rpm_kernel_name}" ]; then
                 rpm -ivh ${rpm_kernel_name}
             else
                 echo -e "${red}Error:${plain} Download ${rpm_kernel_name} failed, please check it."
                 exit
             fi
             if [ -f "${rpm_kernel_devel_name}" ]; then
                 rpm -ivh ${rpm_kernel_devel_name}
             else
                 echo -e "${red}Error:${plain} Download ${rpm_kernel_devel_name} failed, please check it."
                 exit
             fi
             rm -f ${rpm_kernel_name} ${rpm_kernel_devel_name}
         elif centosversion ; then
             yum -y install kernel-ml kernel-ml-devel
             if [ $? -ne  ]; then
                 echo -e "${red}Error:${plain} Install latest kernel failed, please check it."
                 exit
             fi
         fi
     elif [[ x"${release}" == x"debian" || x"${release}" == x"ubuntu" ]]; then
         [[ ! -e "/usr/bin/wget" ]] && apt-get -y update && apt-get -y install wget
         echo -e "${green}Info:${plain} Getting latest kernel version..."
         get_latest_version
         if [ -n ${modules_deb_name} ]; then
             wget -c -t3 -T60 -O ${deb_kernel_modules_name} ${deb_kernel_modules_url}
             if [ $? -ne  ]; then
                 echo -e "${red}Error:${plain} Download ${deb_kernel_modules_name} failed, please check it."
                 exit
             fi
         fi
         wget -c -t3 -T60 -O ${deb_kernel_name} ${deb_kernel_url}
         if [ $? -ne  ]; then
             echo -e "${red}Error:${plain} Download ${deb_kernel_name} failed, please check it."
             exit
         fi
         [ -f ${deb_kernel_modules_name} ] && dpkg -i ${deb_kernel_modules_name}
         dpkg -i ${deb_kernel_name}
         rm -f ${deb_kernel_name} ${deb_kernel_modules_name}
     else
         echo -e "${red}Error:${plain} OS is not be supported, please change to CentOS/Debian/Ubuntu and try again."
         exit
     fi

     install_config
     sysctl_config
     reboot_os
 }

 clear
 echo "---------- System Information ----------"
 echo " OS      : $opsy"
 echo " Arch    : $arch ($lbit Bit)"
 echo " Kernel  : $kern"
 echo "----------------------------------------"
 echo " Auto install latest kernel for TCP BBR"
 echo
 echo " URL: https://teddysun.com/489.html"
 echo "----------------------------------------"
 echo
 echo "Press any key to start...or Press Ctrl+C to cancel"
 char=`get_char`

 install_bbr >& | tee ${cur_dir}/install_bbr.log

也可以采用在线安装的方式：

wget --no-check-certificate https://github.com/teddysun/across/raw/master/bbr.sh && chmod +x bbr.sh && ./bbr.sh

安装完成后，脚本会提示需要重启 VPS，输入 y 并回车后重启。
重启完成后，进入 VPS，验证一下是否成功安装最新内核并开启 TCP BBR，输入命令：

uname -r

查看内核版本，显示为最新版就表示 OK了

sysctl net.ipv4.tcp_available_congestion_control
返回值一般为：
net.ipv4.tcp_available_congestion_control = bbr cubic reno
或者为：
net.ipv4.tcp_available_congestion_control = reno cubic bbr
=================================================================================
sysctl net.ipv4.tcp_congestion_control
返回值一般为：
net.ipv4.tcp_congestion_control = bbr
=================================================================================
sysctl net.core.default_qdisc
返回值一般为：
net.core.default_qdisc = fq
==================================================================================
lsmod | grep bbr
返回值有 tcp_bbr 模块即说明 bbr 已启动。注意：并不是所有的 VPS 都会有此返回值，若没有也属正常。

另外：

附上大佬的CentOS 下最新版内核 headers 安装方法

本来打算在脚本里直接安装 kernel-ml-headers，但会出现和原版内核 headers 冲突的问题。因此在这里添加一个脚本执行完后，手动安装最新版内核 headers 之教程。
执行以下命令

yum --enablerepo=elrepo-kernel -y install kernel-ml-headers
根据 CentOS 版本的不同，此时一般会出现类似于以下的错误提示：

Error: kernel-ml-headers conflicts with kernel-headers-2.6.32-696.20.1.el6.x86_64
Error: kernel-ml-headers conflicts with kernel-headers-3.10.0-693.17.1.el7.x86_64
因此需要先卸载原版内核 headers ，然后再安装最新版内核 headers。执行命令：

yum remove kernel-headers
确认无误后，输入 y，回车开始卸载。注意，有时候这么操作还会卸载一些对内核 headers 依赖的安装包，比如 gcc、gcc-c++ 之类的。不过不要紧，我们可以在安装完最新版内核 headers 后再重新安装回来即可。
卸载完成后，再次执行上面给出的安装命令。

yum --enablerepo=elrepo-kernel -y install kernel-ml-headers
成功安装后，再把那些之前对内核 headers 依赖的安装包，比如 gcc、gcc-c++ 之类的再安装一次即可。

为什么要安装最新版内核 headers 呢？
这是因为 ss-libev 版有个 tcp fast open 功能，如果不安装的话，这个功能是无法开启的。

内核升级方法
如果是 CentOS 系统，执行如下命令即可升级内核：

yum -y install kernel-ml kernel-ml-devel
如果你还手动安装了新版内核 headers ，那么还需要以下命令来升级 headers ：

yum -y install kernel-ml-headers
CentOS 6 的话，执行命令：

sed -i 's/^default=.*/default=0/g' /boot/grub/grub.conf
CentOS 7 的话，执行命令：

grub2-set-default 0
如果是 Debian/Ubuntu 系统，则需要手动下载最新版内核来安装升级。
去这里下载最新版的内核 deb 安装包。
如果系统是 64 位，则下载 amd64 的 linux-image 中含有 generic 这个 deb 包；
如果系统是 32 位，则下载 i386 的 linux-image 中含有 generic 这个 deb 包；
安装的命令如下（以最新版的 64 位 4.12.4 举例而已，请替换为下载好的 deb 包）：

dpkg -i linux-image-4.12.4-041204-generic_4.12.4-041204.201707271932_amd64.deb
安装完成后，再执行命令：

/usr/sbin/update-grub
最后，重启 VPS 即可。

特别说明
如果你使用的是 Google Cloud Platform （GCP）更换内核，有时会遇到重启后，整个磁盘变为只读的情况。只需执行以下命令即可恢复：

mount -o remount rw /

参考链接：

https://github.com/google/bbr/blob/master/Documentation/bbr-quick-start.md
http://elrepo.org/tiki/tiki-index.php
http://kernel.ubuntu.com/~kernel-ppa/mainline/

https://teddysun.com/489.html