LKL BBR for Centos 7

How it works

   +---------------------------------------------------------------------------+
   |                                                                           |
   |                                                                           |
   |               +--------------+                       +----------------+   |
   |               |              |                       |                |   |
   |   +-----------> iptables *nat+------+            +--->Application(ss) +---+
   |   |           |              |      |            |   |                |
+--v---+---+       +--------------+      |            |   +----------------+
|          |                             |            |
|          |       +---------------------v------------+--------------------+
| Internet |       |                      tap0 device                      |
|          |       +---------------------+------------^--------------------+
|          |                             |            |
+----------+                             |            |
                                  +------v------------+--------+
                                  |                            |
                                  |  haproxy under lkl kernel, |
                                  |  with bbr-tcp stack        |
                                  |                            |
                                  +----------------------------+

By combinating several components (graph above), this solution makes it possible to have tcp-bbr stack running on non-hardwared virtualizations (specificly, openvz). But this also works on kvm/vmware/everything else, and without installing third party kernels and boot configures.

What are them concisted of ?

The project contains binary executables, which are complied from projects listed below:

• Linux Kernel LKL https://github.com/lkl/linux
• Shadowsock-libev https://github.com/shadowsocks/shadowsocks-libev
• Shadowsocks Simple-obfs https://github.com/shadowsocks/simple-obfs

And with some more applications installed from OS sources (epel repository).

• iptables
• haproxy
• dependencies ...(pcre openssl mbedtls libsodium libev c-ares libcap)

How do I set up?

Under Centos 7 64bit OS, run

yum install -y git
git clone https://github.com/cutelua/bbr-lader.git
./bbr-lader/setup.sh

Why not other OSs ?

Since this solution is for lowend vps which provide limited OSs to choose. Among those providers, CentOS 7 is rather common. Considering binary compatability, obfs-server and shadowsocks-libev should work also on Fedora but I never tested.

How to compile (skip this if you're a normal user)

If you'd like to port the project running under other OS, it's fully possible.

liblkl-hijack.so

The customized lkl kernel here, is a bit different by selecting BBR and only as the default TCP alogrithm, removing filesystem supports, to reduce size, etc. The kernel config is lklconfig. By compile your own liblkl-hijack.so, clone the lkl source, copy lklconfig as .config in the root directory, and run

sed -i 's/defconfig/oldconfig/' tools/lkl/Makefile
make -C tools/lkl

Other headups please refer to the lkl project, lastly remember to strip the liblkl-hijack.so, it trims size to around 6 MiB.

obfs-server

Nothing is customized, refer to the simple-obfs project.

About shadowsocks service ?

Defaultly, 2 shadowsocks service is up running on port 80 and 443 under obfuscating as http/https protocols.

Set your clients as listed below, and everything should just work.

Config 1

• IP: YOUR.SERVER.IP
• PORT: 80
• PASSWORD: lkl666
• METHOD: rc4-md5
• PLUGIN: obfs-local
• PLUGIN_OPTS: obfs=http;obfs-host=outlook.office.com

Config 2

• IP: YOUR.SERVER.IP
• PORT: 443
• PASSWORD: lkl666
• METHOD: rc4-md5
• PLUGIN: obfs-local
• PLUGIN_OPTS: obfs=tls;obfs-host=outlook.office.com

For security reasons, it'd be better for you (or not if you're lazy) to change the PASSWORD/METHOD in your own flavor. To do so, edit files under /etc/shadowsocks-libev accordingly.

On finished editing, restart shadowsocks service by commands:

• systemctl restart shadowsocks-libev-server@obfstls
• systemctl restart shadowsocks-libev-server@obfshttp

And if you do not want/need obfuscating, remove plugin lines in the config json. example as below:

{
    "server":"0.0.0.0",
    "server_port":443,
    "password":"lkl666",
    "timeout":600,
    "method":"aes-256-gcm"
}

One last thing, if you want to use other ports, there are more to configure, and hope you do understand them all:

• iptables /etc/sysconfig/iptables (systemctl restart iptables to restart after changing, same below)
• haproxy /etc/haproxy/haproxy.cfg (systemctl restart haproxy, this might have problems, try ifup tap0, restart OS if needed)
• Shadowsocks /etc/shadowsocks-libev/*.json( see ablove )

You might need to figure out how all this components working together, to customize them.

Finally, have luck and hope your server won't get blocked.