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package main
import (
"fmt"
"math/rand"
"net"
"os"
"time"
flag "github.com/spf13/pflag"
)
var version string
const (
configErrorCode = 1
initErrorCode = 2
)
func main() {
var protocol string
var bindAddr string
var delayParam string
var port uint16
var uid uint16
var gid uint16
var versionFlag bool
flag.StringVarP(&protocol, "proto", "P", "ssh", "protocol to tarpit")
flag.StringVarP(&delayParam, "delay", "d", "10s", "delay between the tarpit keep-alive data packets")
flag.StringVarP(&bindAddr, "bind-address", "b", "", "address to bind the socket to")
flag.Uint16VarP(&port, "port", "p", 0, "TCP port, leave it 0 for service default")
flag.Uint16VarP(&uid, "uid", "u", 0, "setuid, after creating a listening socket")
flag.Uint16VarP(&gid, "gid", "g", 0, "setgid, after creating a listening socket")
flag.BoolVarP(&versionFlag, "version", "v", false, "show current version")
flag.Parse()
if versionFlag {
fmt.Println("tarpit version", version)
return
}
handler, defaultPort, err := protocolHandler(protocol)
assert(err, "protocol handler", configErrorCode)
if port == 0 {
port = defaultPort
}
delay, err := time.ParseDuration(delayParam)
assert(err, "parse delay", configErrorCode)
bind := fmt.Sprintf("%s:%d", bindAddr, port)
ln, err := net.Listen("tcp", bind)
assert(err, "server listen", initErrorCode)
// Change uid / gid after creating a socket (required for privileged ports)
err = setGID(gid)
assert(err, "unable to setgid", initErrorCode)
err = setUID(uid)
assert(err, "unable to setuid", initErrorCode)
rand.Seed(time.Now().UnixNano())
fmt.Printf("** Server listening on %s\n", bind)
for {
conn, err := ln.Accept()
if err != nil {
continue
}
go connHandler(handler, conn, delay)
}
}
func assert(err error, msg string, code int) {
if err == nil {
return
}
fmt.Fprintf(os.Stderr, "ERR: %s; %s \n", msg, err.Error())
os.Exit(code)
}
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