This document discusses Shadowsocks, an encrypted proxy protocol. It provides information on Shadowsocks implementations in various programming languages including Go. It also summarizes the key code aspects for the Shadowsocks Go server, including how it handles incoming connections by parsing them, dialing to remote servers, and piping data between connections.

1. Source code reading and implementation learning
Shadowsocks Go
Eric-Guo Github
@ericguo Ruby-China
@ecguo Twiter
2017-06-20

2. What’s Shadowsocks
❖ https://shadowsocks.org/en/spec/Protocol.html
❖ Shadowsocks is a secure split proxy loosely based on SOCKS5.
❖ client <---> ss-local <--[encrypted]--> ss-remote <---> target

3. Shadowsocks vs …
❖ StrongSwan
❖ OpenVPN
❖ PPTP
❖ sshuttle

4. SS is abbreviation of ShadowSocks
SS vs SSR
https://github.com/shadowsocks/shadowsocks
https://www.zybuluo.com/yiranphp/note/632579
https://github.com/shadowsocksr/shadowsocksr
https://github.com/breakwa11/shadowsocks-
rss/issues/38#issuecomment-243106134

5. Shadowsocks Implementation
❖ https://shadowsocks.org/en/spec/Implementations.html
❖ Python
❖ C
❖ Node.js
❖ Go
❖ Ruby
❖ Erlang

6. Shadowsocks Enhance
❖ DNS (UDP) relay
❖ OTA
❖ AEAD
❖ kcptun
❖ obfsplugin

7. Shadowsocks Go
❖ Client & Server
❖ Original SS
❖ OTA (deprecated)
❖ UDP relay on server side support

8. Code Reading - server main
❖ cmd/shadowsocks-server/server.go:312 run(port, password string)
❖ To listen the incoming link from ss client
❖ cmd/shadowsocks-server/server.go:111 handleConnection(conn *ss.Conn)
❖ Parse incoming conn, Dial to remote, Pipe line both conn and remote
❖ cmd/shadowsocks-server/server.go:18 PipeThenClose(src, dst net.Conn)
❖ Read src and Write to dst

9. Code Reading - parse incoming conn
❖ Three type of typeIPv4, typeIPv6 and typeDm.
❖ typeDm used in browser

10. Code Reading - ss.NewConn
❖ shadowsocks-go/shadowsocks/conn.go
❖ shadowsocks-go/shadowsocks/encrypt.go