ruoshan / origdst

Wrapper for getsockopt with SO_ORIGINAL_DST option

Wrapper for getsockopt with SO_ORIGINAL_DST

Use this pkg to retrieve the original destination address after the packets are REDIERCTed by an iptables rule.

Usage:

import "github.com/ruoshan/origdst

func demo() {
    addr, err := origdst.GetOriginalDst(c)
    ...
}

directory demo is a simple TCP server that print the original destination addr, try

# in terminal window A
iptable -t nat -A OUTPUT -p tcp --dport 8888 -j REDIRECT --to-port 9999
cd demo
go run .

# in terminal window B
telnet 127.0.0.1 8888
# you should see the msg in window A