Akari

1. Introduction

This project is:

• A TLS termination proxy
• Routed traffic via TLS SNI (Server Name Indication)
• Implement TCP proxy, HTTP proxy and SOCKS5 proxy over TLS
• Implement multiplexing on server and agent via smux
• Implement connection pool on agent

This project is inspired by ESNI and wildcard certs:

• When server name is encrypted in TLS handshake, it can be used as a key to route traffic
• When wildcard certs is deployed on server, we do not need to add DNS for every sub domain, SNI can be set on agent

2. Requirement

• Domain
• Wildcard Cert
• Virtual Private Server

2.1 Domain

Cloudflare, DNSPod, Aliyun or any other provider that supports DNS API to issue wildcard cert.

2.2 Wildcard Cert

Refer to acme.sh

2.3 Virtual Private Server

• BandwagonHost
• Vultr
• ...

VPS with AES and AVX2 instruction set is recommended.

3. Configuration

3.1 Server

Server listens on one public address and route traffic according to SNI proxy config.

akari config

Field	Type	Comment
LogLevel	int	debug=5, info=4, warn=3, error=2, fatal=1, panic=0 (default 4)
Mode	string	server or agent, use server on server
Addr	string	listening address of server
Conf	string	SNI based proxy config folder path, all json files under this folder are loaded on start
HTTPRedirect	bool	enable http redirect for https mode sni
TLS	object	TLS config, contains ForwardSecurity switchy and a group of TLS certs

SNI based proxy config

Field	Type	Comment
sni	string	server name
mode	string	tcp, socks5 and https are supported
auth	string	user:password format auth string, supported by socks5 and https mode
mux	bool	multiplexing conn switch
addr	string	dst addr, supported by tcp mode
ReverseProxy	map[string]string	http path and dst addr, supported by https mode

mode in this config:

• tcp: tcp proxy, offloading TLS and redirect tcp flow to dst addr
• socks5: socks5 proxy over tls, support auth and no auth, only connect is implemented currently
• https: https proxy, support auth and no auth, only connect is implemented

3.2 Agent

Agent works as a TLS forward proxy at local, listens multiple address according to SNI proxy config and redirect traffic to corresponding server.

akari config

Field	Type	Comment
LogLevel	int	debug=5, info=4, warn=3, error=2, fatal=1, panic=0 (default 4)
Mode	string	server or agent, use agent on agent
Conf	string	SNI based proxy config folder path, all

SNI based proxy config

Field	Type	Comment
sni	string	server name
remote	string	remote server address
local	string	local listeing address
mux	bool	multiplexing conn switch
pool	bool	conn pool switch
maxIdle	int	max idle mux conn when conn pool is enabled
maxMux	int	max multiplexing conn on one underlying mux conn when conn pool is enabled

4. Example

4.1 Server

/etc/akari

➜  ~ tree /etc/akari
/etc/akari
├── akari.json
├── cert
│   ├── example_ecc.key
│   ├── example_ecc.pem
│   ├── example.key
│   └── example.pem
└── conf
    ├── mux-tcp.json
    ├── mux-https.json
    ├── mux-socks5.json
    ├── tcp.json
    ├── https.json
    └── socks5.json

/etc/akari/akari.json

{
    "LogLevel": 5,
    "Mode": "server",
    "Addr": "0.0.0.0:443",
    "Conf": "/etc/akari/conf",
    "TLS": {
        "ForwardSecurity": true,
        "Certs": [
            {
                "Cert": "/etc/akari/cert/example_ecc.pem",
                "Key": "/etc/akari/cert/example_ecc.key"
            },
            {
                "Cert": "/etc/akari/cert/example.pem",
                "Key": "/etc/akari/cert/example.key"
            }
        ]
    }
}

socks5 proxy and multiplexing socks5 proxy

/etc/akari/conf/socks5.json

{
    "sni":"xxxxx-socks5.example.com",
    "auth":"user:password",
    "mode":"socks5"
}

/etc/akari/conf/mux-socks5.json

{
    "sni":"xxxxx-mux-socks5.example.com",
    "mode":"socks5",
    "auth":"user:password",
    "mux": true
}

https proxy and multiplexing https proxy

/etc/akari/conf/https.json

{
    "sni":"xxxxx-https.example.com",
    "auth":"user:password",
    "mode":"https",
    "reverseProxy": {
        "/23336666":"127.0.0.1:23336",
        "/66662333":"127.0.0.1:62333"
    }
}

/etc/akari/conf/mux-https.json

{
    "sni":"xxxxx-mux-https.example.com",
    "mode":"https",
    "auth":"user:password",
    "mux": true
}

tcp proxy and multiplexing tcp proxy

/etc/akari/conf/tcp.json

{
    "sni":"xxxxx-tcp.example.com",
    "mode":"tcp",
    "addr": "127.0.0.1:8080"
}

/etc/akari/conf/mux-tcp.json

{
    "sni":"xxxxx-tcp.example.com",
    "mode":"tcp",
    "addr": "127.0.0.1:8080",
    "mux": true
}

4.2 Agent

/etc/akari

/etc/akari
├── akari.json
└── conf
    ├── mux-tcp.json
    ├── mux-https.json
    ├── mux-socks5.json
    ├── tcp.json
    ├── https.json
    └── socks5.json

/etc/akari/akari.json

{
    "LogLevel": 5,
    "Mode": "agent",
    "Conf": "/etc/akari/conf"
}

socks5 proxy and multiplexing socks5 proxy

/etc/akari/conf/socks5.json

{
        "sni": "xxxxx-socks5.example.com",
        "remote": "xx.xx.xx.xx:443",
        "local": "0.0.0.0:1080"
}

/etc/akari/conf/mux-socks5.json

{
        "sni": "xxxxx-mux-socks5.example.com",
        "remote": "xx.xx.xx.xx:443",
        "local": "0.0.0.0:2080",
        "mux": true,
        "pool": true,
        "maxIdle": 8,
        "maxMux": 8
}

Since agent only works as a TLS forward proxy at local, we don't store application layer auth here, tcp and https proxy format are the same just the same expect for sni, remote and local field.

4.3 Start Service

Run command: /usr/local/bin/akari -c /etc/akari/akari.json

from https://github.com/mikumaycry/akari