最後更新: 2018-09-21

介紹

socat (SOcket CAT) 是一個可以用來做 bidirectional data transfer 的工具來.

在 relay 方面, 它比 nc 強大.

用法:

# 查看 Version 及 Features

socat -V

# 一般 Usage

socat [options] <address1> <address2>

功用:

address1 ---> address2

options:

-lf <logfile>       # Writes messages to <logfile> [filename] instead of stderr.

-L<lockfile>      # If lockfile exists, exits with error.

W<lockfile>      # If lockfile exists, waits until it disappears.

-u                    # Uses unidirectional mode. address1: reading, address2: writing

Address 的格式:

address type separated by ":"

address options separated by ','

Type:

• TCP-LISTEN:<port>
• OPEN:<filename>
• TCP:<host>:<port>
• EXEC:<command-line>

Example

# listen port 12345

socat tcp-listen:12345 -

# Send "test" to remote(192.168.123.10)

echo  "test"   |    socat   -    tcp:192.168.123.10:12345

# Send file

# 收

ip1 # socat -u open:a.txt tcp-listen:9000

# 發

ip2 # socat -u tcp:ip1:9000 open:a.txt,create

# Serail port to network

socat /tmp/serial tcp-listen:9000 &

# Redirect

socat TCP4-LISTEN:80,reuseaddr,fork TCP4:192.168.123.12:8080

多連接 時要用到的 options

fork:

After establishing a connection, handles its channel in a child process and

keeps the parent process attempting to produce more connections,

either by listening or by connecting in a loop

reuseaddr:

Allows other sockets to bind to an address even if parts of it (e.g. the local port) are already in use by socat (example).

# Run Prage when connect

socat TCP-LISTEN:1234,reuseaddr,fork EXEC:./helloworld

Unix Socket

# OpenVPN STATISTICS

echo status | socat - unix-connect:/var/lib/openvpn/mgt-nas.sock

# As telnet

socat - unix-connect:/var/lib/openvpn/mgt-nas.sock