# shadowsocks-libev

## Intro

[Shadowsocks-libev](https://shadowsocks.org) is a lightweight secured SOCKS5
proxy for embedded devices and low-end boxes.

It is a port of [Shadowsocks](https://github.com/shadowsocks/shadowsocks)
created by [@clowwindy](https://github.com/clowwindy), and maintained by
[@madeye](https://github.com/madeye) and [@linusyang](https://github.com/linusyang).

Current version: 3.0.1 | [Changelog](debian/changelog)

Travis CI: [![Travis CI](https://travis-ci.org/shadowsocks/shadowsocks-libev.svg?branch=master)](https://travis-ci.org/shadowsocks/shadowsocks-libev)

## Features

Shadowsocks-libev is written in pure C and depends on
[libev](http://software.schmorp.de/pkg/libev.html).

In normal usage, the memory footprint is about 600KB and the CPU utilization is
no more than 5% on a low-end router (Buffalo WHR-G300N V2 with a 400MHz MIPS CPU,
32MB memory and 4MB flash).

For a full list of feature comparison between different versions of shadowsocks,
refer to the [Wiki page](https://github.com/shadowsocks/shadowsocks/wiki/Feature-Comparison-across-Different-Versions).

## Prerequisites

### Get the latest source code

To get the latest source code, you should also update the submodules as following:

```bash
git clone https://github.com/shadowsocks/shadowsocks-libev.git
cd shadowsocks-libev
git submodule update --init --recursive
```

### Build and install with recent mbedTLS and libsodium

You have to install libsodium 1.0.8 or later before building.

If your system is too old to provide libmbedtls and libsodium (later than **v1.0.8**),
you will need to either install those libraries manually or upgrade your system.

If your system provides with those libraries, you **should** **not** install them
from source. You should jump this section and install them from distribution
repository instead.

```bash
export LIBSODIUM_VER=1.0.11
export MBEDTLS_VER=2.4.0
wget https://download.libsodium.org/libsodium/releases/libsodium-$LIBSODIUM_VER.tar.gz
tar xvf libsodium-$LIBSODIUM_VER.tar.gz
pushd libsodium-$LIBSODIUM_VER
./configure --prefix=/usr && make
sudo make install
popd
wget https://tls.mbed.org/download/mbedtls-$MBEDTLS_VER-gpl.tgz
tar xvf mbedtls-$MBEDTLS_VER-gpl.tgz
pushd mbedtls-$MBEDTLS_VER
make SHARED=1 CFLAGS=-fPIC
sudo make install
popd
```

## Installation

### Distribution-specific guide

- [Debian & Ubuntu](#debian--ubuntu)
    + [Install from repository](#install-from-repository)
    + [Build deb package from source](#build-deb-package-from-source)
    + [Configure and start the service](#configure-and-start-the-service)
- [Fedora & RHEL](#fedora--rhel)
    + [Build from source with centos](#build-from-source-with-centos)
    + [Install from repository](#install-from-repository-1)
- [Archlinux](#archlinux)
- [NixOS](#nixos)
- [Nix](#nix)
- [Directly build and install on UNIX-like system](#linux)
- [FreeBSD](#freebsd)
- [OpenWRT](#openwrt)
- [OS X](#os-x)
- [Windows](#windows)

* * *

### Pre-build configure guide

For a complete list of avaliable configure-time option,
try `configure --help`.

### Debian & Ubuntu

#### Install from repository

**Note: The repositories doesn't always contain the latest version. Please build from source if you want the latest version (see below)**

Shadowsocks-libev is available in the official repository for Debian 9("Stretch"), unstable, Ubuntu 16.10 and later derivatives:

```bash
sudo apt update
sudo apt install shadowsocks-libev
```

For Debian Jessie users, please install it from `jessie-backports`:

```bash
sudo sh -c 'printf "deb http://httpredir.debian.org/debian jessie-backports main" > /etc/apt/sources.list.d/jessie-backports.list'
sudo apt update
sudo apt -t jessie-backports install shadowsocks-libev
```

#### Build deb package from source

Supported Platforms:

* Debian 8 (see below), 9, unstable
* Ubuntu 16.04 or higher

For older systems, building `.deb` packages is not supported.
Please directly install from source.
You may need to resolve library dependencies by yourself.

**Note for Debian 8.x users**:
We strongly encourage you to install shadowsocks-libev from `jessie-backports`.
Please follow instructions on [Debian Backports](https://backports.debian.org).

If you insist on building from source, you will need to manually install libsodium
from `jessie-backports`, **NOT** libsodium in main repository.
Please follow the instructions on [Debian Backports Website](https://backports.debian.org).

Otherwise, try to build and install directly from source. See the [Linux](#linux)
section below.

``` bash
cd shadowsocks-libev
sudo apt-get install --no-install-recommends gettext build-essential autoconf automake libtool \
    gawk debhelper dh-systemd init-system-helpers pkg-config asciidoc xmlto apg libpcre3-dev \
    libev-dev libudns-dev dh-autoreconf
./autogen.sh && dpkg-buildpackage -b -us -uc -i
cd ..
sudo dpkg -i shadowsocks-libev*.deb
```

#### Configure and start the service

```
# Edit the configuration file
sudo vim /etc/shadowsocks-libev/config.json

# Edit the default configuration for debian
sudo vim /etc/default/shadowsocks-libev

# Start the service
sudo /etc/init.d/shadowsocks-libev start    # for sysvinit, or
sudo systemctl start shadowsocks-libev      # for systemd
```

### Fedora & RHEL

Supported distributions include
- Fedora 22, 23, 24
- RHEL 6, 7 and derivatives (including CentOS, Scientific Linux)

#### Build from source with centos

If you are using CentOS 7, you need to install these prequirement to build from source code

```bash 
yum install epel-release -y
yum install gcc gettext autoconf libtool automake make pcre-devel asciidoc xmlto udns-devel libev-devel -y
```

#### Install from repository

Enable repo via `dnf`:

```
su -c 'dnf copr enable librehat/shadowsocks'
```

Or download yum repo on [Fedora Copr](https://copr.fedoraproject.org/coprs/librehat/shadowsocks/) and put it inside `/etc/yum.repos.d/`. The release `Epel` is for RHEL and its derivatives.

Then, install `shadowsocks-libev` via `dnf`:

```bash
su -c 'dnf update'
su -c 'dnf install shadowsocks-libev'
```

or `yum`:

```bash
su -c 'yum update'
su -c 'yum install shadowsocks-libev'
```
### Archlinux

```bash
sudo pacman -S shadowsocks-libev
```

Please refer to downstream [PKGBUILD](https://projects.archlinux.org/svntogit/community.git/tree/trunk?h=packages/shadowsocks-libev)
script for extra modifications and distribution-specific bugs.

### NixOS

```bash
nix-env -iA nixos.shadowsocks-libev
```

### Nix

```bash
nix-env -iA nixpkgs.shadowsocks-libev
```

### Linux

In general, you need the following build dependencies:

* autotools (autoconf, automake, libtool)
* gettext
* pkg-config
* libmbedtls
* libsodium
* libpcre3 (old pcre library)
* libev
* libudns
* asciidoc (for documentation only)
* xmlto (for documentation only)

For Unix-like systems, especially Debian-based systems,
e.g. Ubuntu, Debian or Linux Mint, you might install build dependencies like this:

```bash
# Debian / Ubuntu
sudo apt-get install --no-install-recommends gettext build-essential autoconf libtool libpcre3-dev asciidoc xmlto libev-dev libudns-dev automake libmbedtls-dev
# CentOS / Fedora / RHEL
sudo yum install gettext gcc autoconf libtool automake make asciidoc xmlto udns-devel libev-devel
# Arch
sudo pacman -S gettext gcc autoconf libtool automake make asciidoc xmlto udns libev
./autogen.sh && ./configure && make
sudo make install
```

You may need to manually install missing softwares.

### FreeBSD

```bash
su
cd /usr/ports/net/shadowsocks-libev
make install
```

Edit your config.json file. By default, it's located in /usr/local/etc/shadowsocks-libev.

To enable shadowsocks-libev, add the following rc variable to your /etc/rc.conf file:

```
shadowsocks_libev_enable="YES"
```

Start the Shadowsocks server:

```bash
service shadowsocks_libev start
```

### OpenWRT

The OpenWRT project is maintained here:
[openwrt-shadowsocks](https://github.com/shadowsocks/openwrt-shadowsocks).

### OS X
For OS X, use [Homebrew](http://brew.sh) to install or build.

Install Homebrew:

```bash
ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
```
Install shadowsocks-libev:

```bash
brew install shadowsocks-libev
```

## Usage

For a detailed and complete list of all supported arguments, you may refer to the
man pages of the applications, respectively.

```
    ss-[local|redir|server|tunnel]

       -s <server_host>           host name or ip address of your remote server

       -p <server_port>           port number of your remote server

       -l <local_port>            port number of your local server

       -k <password>              password of your remote server

       -m <encrypt_method>        Encrypt method: rc4-md5,
                                  aes-128-gcm, aes-192-gcm, aes-256-gcm,
                                  aes-128-cfb, aes-192-cfb, aes-256-cfb,
                                  aes-128-ctr, aes-192-ctr, aes-256-ctr,
                                  camellia-128-cfb, camellia-192-cfb,
                                  camellia-256-cfb, bf-cfb,
                                  chacha20-poly1305, chacha20-ietf-poly1305
                                  salsa20, chacha20 and chacha20-ietf.

       [-f <pid_file>]            the file path to store pid

       [-t <timeout>]             socket timeout in seconds

       [-c <config_file>]         the path to config file

       [-i <interface>]           network interface to bind,
                                  not available in redir mode

       [-b <local_address>]       local address to bind,
                                  not available in server mode

       [-u]                       enable udprelay mode,
                                  TPROXY is required in redir mode

       [-U]                       enable UDP relay and disable TCP relay,
                                  not available in local mode

       [-L <addr>:<port>]         specify destination server address and port
                                  for local port forwarding,
                                  only available in tunnel mode

       [-d <addr>]                setup name servers for internal DNS resolver,
                                  only available in server mode

       [--fast-open]              enable TCP fast open,
                                  only available in local and server mode,
                                  with Linux kernel > 3.7.0

       [--acl <acl_file>]         config file of ACL (Access Control List)
                                  only available in local and server mode

       [--manager-address <addr>] UNIX domain socket address
                                  only available in server and manager mode

       [--executable <path>]      path to the executable of ss-server
                                  only available in manager mode

       [--plugin <name>]          Enable SIP003 plugin. (Experimental)
       [--plugin-opts <options>]  Set SIP003 plugin options. (Experimental)

       [-v]                       verbose mode

notes:

    ss-redir provides a transparent proxy function and only works on the
    Linux platform with iptables.

```

## Advanced usage

The latest shadowsocks-libev has provided a *redir* mode. You can configure your Linux-based box or router to proxy all TCP traffic transparently.

    # Create new chain
    root@Wrt:~# iptables -t nat -N SHADOWSOCKS
    root@Wrt:~# iptables -t mangle -N SHADOWSOCKS
    root@Wrt:~# iptables -t mangle -N SHADOWSOCKS_MARK

    # Ignore your shadowsocks server's addresses
    # It's very IMPORTANT, just be careful.
    root@Wrt:~# iptables -t nat -A SHADOWSOCKS -d 123.123.123.123 -j RETURN

    # Ignore LANs and any other addresses you'd like to bypass the proxy
    # See Wikipedia and RFC5735 for full list of reserved networks.
    # See ashi009/bestroutetb for a highly optimized CHN route list.
    root@Wrt:~# iptables -t nat -A SHADOWSOCKS -d 0.0.0.0/8 -j RETURN
    root@Wrt:~# iptables -t nat -A SHADOWSOCKS -d 10.0.0.0/8 -j RETURN
    root@Wrt:~# iptables -t nat -A SHADOWSOCKS -d 127.0.0.0/8 -j RETURN
    root@Wrt:~# iptables -t nat -A SHADOWSOCKS -d 169.254.0.0/16 -j RETURN
    root@Wrt:~# iptables -t nat -A SHADOWSOCKS -d 172.16.0.0/12 -j RETURN
    root@Wrt:~# iptables -t nat -A SHADOWSOCKS -d 192.168.0.0/16 -j RETURN
    root@Wrt:~# iptables -t nat -A SHADOWSOCKS -d 224.0.0.0/4 -j RETURN
    root@Wrt:~# iptables -t nat -A SHADOWSOCKS -d 240.0.0.0/4 -j RETURN

    # Anything else should be redirected to shadowsocks's local port
    root@Wrt:~# iptables -t nat -A SHADOWSOCKS -p tcp -j REDIRECT --to-ports 12345

    # Add any UDP rules
    root@Wrt:~# ip route add local default dev lo table 100
    root@Wrt:~# ip rule add fwmark 1 lookup 100
    root@Wrt:~# iptables -t mangle -A SHADOWSOCKS -p udp --dport 53 -j TPROXY --on-port 12345 --tproxy-mark 0x01/0x01
    root@Wrt:~# iptables -t mangle -A SHADOWSOCKS_MARK -p udp --dport 53 -j MARK --set-mark 1

    # Apply the rules
    root@Wrt:~# iptables -t nat -A OUTPUT -p tcp -j SHADOWSOCKS
    root@Wrt:~# iptables -t mangle -A PREROUTING -j SHADOWSOCKS
    root@Wrt:~# iptables -t mangle -A OUTPUT -j SHADOWSOCKS_MARK

    # Start the shadowsocks-redir
    root@Wrt:~# ss-redir -u -c /etc/config/shadowsocks.json -f /var/run/shadowsocks.pid

## Shadowsocks over KCP

It's quite easy to use shadowsocks and [KCP](https://github.com/skywind3000/kcp) together with [kcptun](https://github.com/xtaci/kcptun).

The goal of shadowsocks over KCP is to provide a fully configurable, UDP based protocol to improve poor connections, e.g. a high packet loss 3G network.

### Setup your server

```bash
server_linux_amd64 -l :21 -t 127.0.0.1:443 --crypt none --mtu 1200 --nocomp --mode normal --dscp 46 &
ss-server -s 0.0.0.0 -p 443 -k passwd -m chacha20 -u
```

### Setup your client

```bash
client_linux_amd64 -l 127.0.0.1:1090 -r <server_ip>:21 --crypt none --mtu 1200 --nocomp --mode normal --dscp 46 &
ss-local -s 127.0.0.1 -p 1090 -k passwd -m chacha20 -l 1080 -b 0.0.0.0 &
ss-local -s <server_ip> -p 443 -k passwd -m chacha20 -l 1080 -U -b 0.0.0.0
```

## Security Tips

Although shadowsocks-libev can handle thousands of concurrent connections nicely, we still recommend
setting up your server's firewall rules to limit connections from each user:

    # Up to 32 connections are enough for normal usage
    iptables -A INPUT -p tcp --syn --dport ${SHADOWSOCKS_PORT} -m connlimit --connlimit-above 32 -j REJECT --reject-with tcp-reset

## License

```
Copyright: 2013-2015, Clow Windy <clowwindy42@gmail.com>
           2013-2017, Max Lv <max.c.lv@gmail.com>
           2014, Linus Yang <linusyang@gmail.com>

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
```