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KCP

KCP is a data channel type in GOST. The implementation of KCP depends on the xtaci/kcp-go library.

Usage

gost -L kcp://:8443?kcp.configFile=/path/to/config/file

services:
- name: service-0
  addr: ":8443"
  handler:
    type: auto
  listener:
    type: kcp
    metadata:
      # config file
      kcp.configFile: /path/to/config/file
      # config map
      kcp.config:
        key: "it's a secrect"
        crypt: aes
        mode: fast
        mtu: 1350
        tcp: false
        # ...
      # single config option
      kcp.crypt: aes
      kcp.mode: fast

Configuration

GOST has a built-in set of default KCP configuration items, and the default values ​​are consistent with xtaci/kcptun.

You can specify the configuration directly through kcp.config option. You can also specify an external configuration file through kcp.configFile option. The configuration file is in JSON format:

{
    "key": "it's a secrect",
    "crypt": "aes",
    "mode": "fast",
    "mtu" : 1350,
    "sndwnd": 1024,
    "rcvwnd": 1024,
    "datashard": 10,
    "parityshard": 3,
    "dscp": 0,
    "nocomp": false,
    "acknodelay": false,
    "nodelay": 0,
    "interval": 40,
    "resend": 0,
    "nc": 0,
    "smuxver": 1,
    "sockbuf": 4194304,
    "keepalive": 10,
    "snmplog": "",
    "snmpperiod": 60,
    "tcp": false
}

Some parameters can also be specified directly through options:

kcp.tcp:
config.tcp
kcp.key:
config.key
kcp.crypt:
config.crypt
kcp.mode:
config.mode
kcp.keepalive:
config.keepalive
kcp.interval:
config.interval
kcp.mtu:
config.mtu
kcp.smuxver:
config.smuxver

For a description of the parameters in the configuration file, see kcptun.

Proxy

KCP tunnel can be used in combination with various proxy protocols.

HTTP Over KCP

gost -L http+kcp://:8443

services:
- name: service-0
  addr: :8443
  handler:
    type: http
  listener:
    type: kcp

SOCKS5 Over KCP

gost -L socks5+kcp://:8443

services:
- name: service-0
  addr: :8443
  handler:
    type: socks5
  listener:
    type: kcp

Relay Over KCP

gost -L relay+kcp://:8443

services:
- name: service-0
  addr: :8443
  handler:
    type: relay
  listener:
    type: kcp

Port Forwarding

KCP tunnel can also be used as port forwarding.

Server

gost -L kcp://:8443/:8080 -L ss://:8080

is equivalent to

gost -L forward+kcp://:8443/:8080 -L ss://:8080

services:
- name: service-0
  addr: :8443
  handler:
    type: forward
  listener:
    type: kcp
  forwarder:
    nodes:
    - name: target-0
      addr: :8080
- name: service-1
  addr: :8080
  handler:
    type: http
  listener:
    type: tcp

By using port forwarding of the KCP tunnel, a KCP data channel is added to the Shadowsocks proxy service on port 8080.

At this time, port 8443 is equivalent to:

gost -L ss+kcp://:8443

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