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  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：

  1 #!/usr/bin/env bash
  2 #
  3 # auto install latest kernel for tcp bbr
  4 #
  5 # system required:  centos 6+, debian7+, ubuntu12+
  6 #
  7 # copyright (c) 2016-2018 teddysun <[e-mail]>
  8 #
  9 # url: https://teddysun.com/489.html
 10 #
 11 
 12 red='\033[0;31m'
 13 green='\033[0;32m'
 14 yellow='\033[0;33m'
 15 plain='\033[0m'
 16 
 17 cur_dir=$(pwd)
 18 
 19 [[ $euid -ne 0 ]] && echo -e "${red}error:${plain} this script must be run as root!" && exit 1
 20 
 21 [[ -d "/proc/vz" ]] && echo -e "${red}error:${plain} your vps is based on openvz, which is not supported." && exit 1
 22 
 23 if [ -f /etc/redhat-release ]; then
 24     release="centos"
 25 elif cat /etc/issue | grep -eqi "debian"; then
 26     release="debian"
 27 elif cat /etc/issue | grep -eqi "ubuntu"; then
 28     release="ubuntu"
 29 elif cat /etc/issue | grep -eqi "centos|red hat|redhat"; then
 30     release="centos"
 31 elif cat /proc/version | grep -eqi "debian"; then
 32     release="debian"
 33 elif cat /proc/version | grep -eqi "ubuntu"; then
 34     release="ubuntu"
 35 elif cat /proc/version | grep -eqi "centos|red hat|redhat"; then
 36     release="centos"
 37 else
 38     release=""
 39 fi
 40 
 41 is_digit(){
 42     local input=${1}
 43     if [[ "$input" =~ ^[0-9]+$ ]]; then
 44         return 0
 45     else
 46         return 1
 47     fi
 48 }
 49 
 50 is_64bit(){
 51     if [ $(getconf word_bit) = '32' ] && [ $(getconf long_bit) = '64' ]; then
 52         return 0
 53     else
 54         return 1
 55     fi
 56 }
 57 
 58 get_valid_valname(){
 59     local val=${1}
 60     local new_val=$(eval echo $val | sed 's/[-.]/_/g')
 61     echo ${new_val}
 62 }
 63 
 64 get_hint(){
 65     local val=${1}
 66     local new_val=$(get_valid_valname $val)
 67     eval echo "\$hint_${new_val}"
 68 }
 69 
 70 #display memu
 71 display_menu(){
 72     local soft=${1}
 73     local default=${2}
 74     eval local arr=(\${${soft}_arr[@]})
 75     local default_prompt
 76     if [[ "$default" != "" ]]; then
 77         if [[ "$default" == "last" ]]; then
 78             default=${#arr[@]}
 79         fi
 80         default_prompt="(default ${arr[$default-1]})"
 81     fi
 82     local pick
 83     local hint
 84     local vname
 85     local prompt="which ${soft} you'd select ${default_prompt}: "
 86 
 87     while :
 88     do
 89         echo -e "\n------------ ${soft} setting ------------\n"
 90         for ((i=1;i<=${#arr[@]};i++ )); do
 91             vname="$(get_valid_valname ${arr[$i-1]})"
 92             hint="$(get_hint $vname)"
 93             [[ "$hint" == "" ]] && hint="${arr[$i-1]}"
 94             echo -e "${green}${i}${plain}) $hint"
 95         done
 96         echo
 97         read -p "${prompt}" pick
 98         if [[ "$pick" == "" && "$default" != "" ]]; then
 99             pick=${default}
100             break
101         fi
102 
103         if ! is_digit "$pick"; then
104             prompt="input error, please input a number"
105             continue
106         fi
107 
108         if [[ "$pick" -lt 1 || "$pick" -gt ${#arr[@]} ]]; then
109             prompt="input error, please input a number between 1 and ${#arr[@]}: "
110             continue
111         fi
112 
113         break
114     done
115 
116     eval ${soft}=${arr[$pick-1]}
117     vname="$(get_valid_valname ${arr[$pick-1]})"
118     hint="$(get_hint $vname)"
119     [[ "$hint" == "" ]] && hint="${arr[$pick-1]}"
120     echo -e "\nyour selection: $hint\n"
121 }
122 
123 version_ge(){
124     test "$(echo "$@" | tr " " "\n" | sort -rv | head -n 1)" == "$1"
125 }
126 
127 get_latest_version() {
128     latest_version=($(wget -qo- https://kernel.ubuntu.com/~kernel-ppa/mainline/ | awk -f'\"v' '/v[4-9]./{print $2}' | cut -d/ -f1 | grep -v - | sort -v))
129 
130     [ ${#latest_version[@]} -eq 0 ] && echo -e "${red}error:${plain} get latest kernel version failed." && exit 1
131 
132     kernel_arr=()
133     for i in ${latest_version[@]}; do
134         if version_ge $i 4.14; then
135             kernel_arr+=($i);
136         fi
137     done
138 
139     display_menu kernel last
140 
141     if [[ `getconf word_bit` == "32" && `getconf long_bit` == "64" ]]; then
142         deb_name=$(wget -qo- https://kernel.ubuntu.com/~kernel-ppa/mainline/v${kernel}/ | grep "linux-image" | grep "generic" | awk -f'\">' '/amd64.deb/{print $2}' | cut -d'<' -f1 | head -1)
143         deb_kernel_url="https://kernel.ubuntu.com/~kernel-ppa/mainline/v${kernel}/${deb_name}"
144         deb_kernel_name="linux-image-${kernel}-amd64.deb"
145         modules_deb_name=$(wget -qo- https://kernel.ubuntu.com/~kernel-ppa/mainline/v${kernel}/ | grep "linux-modules" | grep "generic" | awk -f'\">' '/amd64.deb/{print $2}' | cut -d'<' -f1 | head -1)
146         deb_kernel_modules_url="https://kernel.ubuntu.com/~kernel-ppa/mainline/v${kernel}/${modules_deb_name}"
147         deb_kernel_modules_name="linux-modules-${kernel}-amd64.deb"
148     else
149         deb_name=$(wget -qo- https://kernel.ubuntu.com/~kernel-ppa/mainline/v${kernel}/ | grep "linux-image" | grep "generic" | awk -f'\">' '/i386.deb/{print $2}' | cut -d'<' -f1 | head -1)
150         deb_kernel_url="https://kernel.ubuntu.com/~kernel-ppa/mainline/v${kernel}/${deb_name}"
151         deb_kernel_name="linux-image-${kernel}-i386.deb"
152         modules_deb_name=$(wget -qo- https://kernel.ubuntu.com/~kernel-ppa/mainline/v${kernel}/ | grep "linux-modules" | grep "generic" | awk -f'\">' '/i386.deb/{print $2}' | cut -d'<' -f1 | head -1)
153         deb_kernel_modules_url="https://kernel.ubuntu.com/~kernel-ppa/mainline/v${kernel}/${modules_deb_name}"
154         deb_kernel_modules_name="linux-modules-${kernel}-i386.deb"
155     fi
156 
157     [ -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 1
158 }
159 
160 get_opsy() {
161     [ -f /etc/redhat-release ] && awk '{print ($1,$3~/^[0-9]/?$3:$4)}' /etc/redhat-release && return
162     [ -f /etc/os-release ] && awk -f'[= "]' '/pretty_name/{print $3,$4,$5}' /etc/os-release && return
163     [ -f /etc/lsb-release ] && awk -f'[="]+' '/description/{print $2}' /etc/lsb-release && return
164 }
165 
166 opsy=$( get_opsy )
167 arch=$( uname -m )
168 lbit=$( getconf long_bit )
169 kern=$( uname -r )
170 
171 get_char() {
172     savedstty=`stty -g`
173     stty -echo
174     stty cbreak
175     dd if=/dev/tty bs=1 count=1 2> /dev/null
176     stty -raw
177     stty echo
178     stty $savedstty
179 }
180 
181 getversion() {
182     if [[ -s /etc/redhat-release ]]; then
183         grep -oe  "[0-9.]+" /etc/redhat-release
184     else
185         grep -oe  "[0-9.]+" /etc/issue
186     fi
187 }
188 
189 centosversion() {
190     if [ x"${release}" == x"centos" ]; then
191         local code=$1
192         local version="$(getversion)"
193         local main_ver=${version%%.*}
194         if [ "$main_ver" == "$code" ]; then
195             return 0
196         else
197             return 1
198         fi
199     else
200         return 1
201     fi
202 }
203 
204 check_bbr_status() {
205     local param=$(sysctl net.ipv4.tcp_congestion_control | awk '{print $3}')
206     if [[ x"${param}" == x"bbr" ]]; then
207         return 0
208     else
209         return 1
210     fi
211 }
212 
213 check_kernel_version() {
214     local kernel_version=$(uname -r | cut -d- -f1)
215     if version_ge ${kernel_version} 4.9; then
216         return 0
217     else
218         return 1
219     fi
220 }
221 
222 install_elrepo() {
223 
224     if centosversion 5; then
225         echo -e "${red}error:${plain} not supported centos 5."
226         exit 1
227     fi
228 
229     rpm --import https://www.elrepo.org/rpm-gpg-key-elrepo.org
230 
231     if centosversion 6; then
232         rpm -uvh https://www.elrepo.org/elrepo-release-6-9.el6.elrepo.noarch.rpm
233     elif centosversion 7; then
234         rpm -uvh https://www.elrepo.org/elrepo-release-7.0-4.el7.elrepo.noarch.rpm
235     fi
236 
237     if [ ! -f /etc/yum.repos.d/elrepo.repo ]; then
238         echo -e "${red}error:${plain} install elrepo failed, please check it."
239         exit 1
240     fi
241 }
242 
243 sysctl_config() {
244     sed -i '/net.core.default_qdisc/d' /etc/sysctl.conf
245     sed -i '/net.ipv4.tcp_congestion_control/d' /etc/sysctl.conf
246     echo "net.core.default_qdisc = fq" >> /etc/sysctl.conf
247     echo "net.ipv4.tcp_congestion_control = bbr" >> /etc/sysctl.conf
248     sysctl -p >/dev/null 2>&1
249 }
250 
251 install_config() {
252     if [[ x"${release}" == x"centos" ]]; then
253         if centosversion 6; then
254             if [ ! -f "/boot/grub/grub.conf" ]; then
255                 echo -e "${red}error:${plain} /boot/grub/grub.conf not found, please check it."
256                 exit 1
257             fi
258             sed -i 's/^default=.*/default=0/g' /boot/grub/grub.conf
259         elif centosversion 7; then
260             if [ ! -f "/boot/grub2/grub.cfg" ]; then
261                 echo -e "${red}error:${plain} /boot/grub2/grub.cfg not found, please check it."
262                 exit 1
263             fi
264             grub2-set-default 0
265         fi
266     elif [[ x"${release}" == x"debian" || x"${release}" == x"ubuntu" ]]; then
267         /usr/sbin/update-grub
268     fi
269 }
270 
271 reboot_os() {
272     echo
273     echo -e "${green}info:${plain} the system needs to reboot."
274     read -p "do you want to restart system? [y/n]" is_reboot
275     if [[ ${is_reboot} == "y" || ${is_reboot} == "y" ]]; then
276         reboot
277     else
278         echo -e "${green}info:${plain} reboot has been canceled..."
279         exit 0
280     fi
281 }
282 
283 install_bbr() {
284     check_bbr_status
285     if [ $? -eq 0 ]; then
286         echo
287         echo -e "${green}info:${plain} tcp bbr has already been installed. nothing to do..."
288         exit 0
289     fi
290     check_kernel_version
291     if [ $? -eq 0 ]; then
292         echo
293         echo -e "${green}info:${plain} your kernel version is greater than 4.9, directly setting tcp bbr..."
294         sysctl_config
295         echo -e "${green}info:${plain} setting tcp bbr completed..."
296         exit 0
297     fi
298 
299     if [[ x"${release}" == x"centos" ]]; then
300         install_elrepo
301         [ ! "$(command -v yum-config-manager)" ] && yum install -y yum-utils > /dev/null 2>&1
302         [ x"$(yum-config-manager elrepo-kernel | grep -w enabled | awk '{print $3}')" != x"true" ] && yum-config-manager --enable elrepo-kernel > /dev/null 2>&1
303         if centosversion 6; then
304             if is_64bit; then
305                 rpm_kernel_name="kernel-ml-4.18.20-1.el6.elrepo.x86_64.rpm"
306                 rpm_kernel_devel_name="kernel-ml-devel-4.18.20-1.el6.elrepo.x86_64.rpm"
307                 rpm_kernel_url_1="http://repos.lax.quadranet.com/elrepo/archive/kernel/el6/x86_64/rpms/"
308             else
309                 rpm_kernel_name="kernel-ml-4.18.20-1.el6.elrepo.i686.rpm"
310                 rpm_kernel_devel_name="kernel-ml-devel-4.18.20-1.el6.elrepo.i686.rpm"
311                 rpm_kernel_url_1="http://repos.lax.quadranet.com/elrepo/archive/kernel/el6/i386/rpms/"
312             fi
313             rpm_kernel_url_2="https://dl.lamp.sh/files/"
314             wget -c -t3 -t60 -o ${rpm_kernel_name} ${rpm_kernel_url_1}${rpm_kernel_name}
315             if [ $? -ne 0 ]; then
316                 rm -rf ${rpm_kernel_name}
317                 wget -c -t3 -t60 -o ${rpm_kernel_name} ${rpm_kernel_url_2}${rpm_kernel_name}
318             fi
319             wget -c -t3 -t60 -o ${rpm_kernel_devel_name} ${rpm_kernel_url_1}${rpm_kernel_devel_name}
320             if [ $? -ne 0 ]; then
321                 rm -rf ${rpm_kernel_devel_name}
322                 wget -c -t3 -t60 -o ${rpm_kernel_devel_name} ${rpm_kernel_url_2}${rpm_kernel_devel_name}
323             fi
324             if [ -f "${rpm_kernel_name}" ]; then
325                 rpm -ivh ${rpm_kernel_name}
326             else
327                 echo -e "${red}error:${plain} download ${rpm_kernel_name} failed, please check it."
328                 exit 1
329             fi
330             if [ -f "${rpm_kernel_devel_name}" ]; then
331                 rpm -ivh ${rpm_kernel_devel_name}
332             else
333                 echo -e "${red}error:${plain} download ${rpm_kernel_devel_name} failed, please check it."
334                 exit 1
335             fi
336             rm -f ${rpm_kernel_name} ${rpm_kernel_devel_name}
337         elif centosversion 7; then
338             yum -y install kernel-ml kernel-ml-devel
339             if [ $? -ne 0 ]; then
340                 echo -e "${red}error:${plain} install latest kernel failed, please check it."
341                 exit 1
342             fi
343         fi
344     elif [[ x"${release}" == x"debian" || x"${release}" == x"ubuntu" ]]; then
345         [[ ! -e "/usr/bin/wget" ]] && apt-get -y update && apt-get -y install wget
346         echo -e "${green}info:${plain} getting latest kernel version..."
347         get_latest_version
348         if [ -n ${modules_deb_name} ]; then
349             wget -c -t3 -t60 -o ${deb_kernel_modules_name} ${deb_kernel_modules_url}
350             if [ $? -ne 0 ]; then
351                 echo -e "${red}error:${plain} download ${deb_kernel_modules_name} failed, please check it."
352                 exit 1
353             fi
354         fi
355         wget -c -t3 -t60 -o ${deb_kernel_name} ${deb_kernel_url}
356         if [ $? -ne 0 ]; then
357             echo -e "${red}error:${plain} download ${deb_kernel_name} failed, please check it."
358             exit 1
359         fi
360         [ -f ${deb_kernel_modules_name} ] && dpkg -i ${deb_kernel_modules_name}
361         dpkg -i ${deb_kernel_name}
362         rm -f ${deb_kernel_name} ${deb_kernel_modules_name}
363     else
364         echo -e "${red}error:${plain} os is not be supported, please change to centos/debian/ubuntu and try again."
365         exit 1
366     fi
367 
368     install_config
369     sysctl_config
370     reboot_os
371 }
372 
373 
374 clear
375 echo "---------- system information ----------"
376 echo " os      : $opsy"
377 echo " arch    : $arch ($lbit bit)"
378 echo " kernel  : $kern"
379 echo "----------------------------------------"
380 echo " auto install latest kernel for tcp bbr"
381 echo
382 echo " url: https://teddysun.com/489.html"
383 echo "----------------------------------------"
384 echo
385 echo "press any key to start...or press ctrl+c to cancel"
386 char=`get_char`
387 
388 install_bbr 2>&1 | 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