Created
May 15, 2019 10:55
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Simple GO TCP proxy
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// From https://gist.github.com/wallrat/3059639 | |
package main | |
import ( | |
"net" | |
"fmt" | |
"io" | |
"os" | |
) | |
func main() { | |
if len(os.Args) != 3 { | |
fatal("usage: netfwd local remote") | |
} | |
localAddr := os.Args[1] | |
remoteAddr := os.Args[2] | |
local, err := net.Listen("tcp", localAddr) | |
if local == nil { | |
fatal("cannot listen: %v", err) | |
} | |
for { | |
conn, err := local.Accept() | |
if conn == nil { | |
fatal("accept failed: %v", err) | |
} | |
go forward(conn, remoteAddr) | |
} | |
} | |
func forward(local net.Conn, remoteAddr string) { | |
remote, err := net.Dial("tcp", remoteAddr) | |
if remote == nil { | |
fmt.Fprintf(os.Stderr, "remote dial failed: %v\n", err) | |
return | |
} | |
go func() { | |
io.Copy(local, remote) | |
local.Close() | |
remote.Close() | |
}() | |
go func() { | |
io.Copy(remote, local) | |
remote.Close() | |
local.Close() | |
}() | |
} | |
func fatal(s string, a ... interface{}) { | |
fmt.Fprintf(os.Stderr, "netfwd: %s\n", fmt.Sprintf(s, a)) | |
os.Exit(2) | |
} |
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