2023-01-28 19:30:56 +01:00
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package main
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import (
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"io"
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"net"
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"os"
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"sync"
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"github.com/integrii/flaggy"
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"github.com/rs/zerolog"
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"github.com/rs/zerolog/log"
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)
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func main() {
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log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr})
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var (
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listenAddr = ":8000"
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forwardAddr string
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2023-03-05 13:39:06 +01:00
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mode = "tcp"
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2023-01-28 19:30:56 +01:00
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)
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flaggy.String(&listenAddr, "l", "listen", "Address to listen on")
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flaggy.String(&forwardAddr, "f", "forward", "Address to forward to")
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2023-03-05 13:39:06 +01:00
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flaggy.String(&mode, "m", "mode", "Mode to use (tcp, udp)")
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2023-01-28 19:30:56 +01:00
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flaggy.Parse()
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if forwardAddr == "" {
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log.Fatal().Msg("Forward address is required")
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}
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2023-03-05 13:39:06 +01:00
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if mode == "tcp" {
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tcpListen(listenAddr, forwardAddr)
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} else if mode == "udp" {
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udpListen(listenAddr, forwardAddr)
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} else {
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log.Fatal().Msg("Invalid mode")
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}
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}
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func tcpListen(listenAddr, forwardAddr string) {
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var (
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ln net.Listener
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err error
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)
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if ln, err = net.Listen("tcp", listenAddr); err != nil {
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log.Panic().Err(err).Str("Mode", "TCP").Msg("Failed to listen")
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2023-01-28 19:30:56 +01:00
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}
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2023-03-05 13:39:06 +01:00
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log.Info().Str("Mode", "TCP").Str("Listen Address", listenAddr).Msg("Listening")
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defer ln.Close()
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2023-01-28 19:30:56 +01:00
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for {
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conn, err := ln.Accept()
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if err != nil {
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2023-03-05 13:39:06 +01:00
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log.Err(err).Str("Mode", "TCP").Msg("Failed to accept connection")
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2023-01-28 19:30:56 +01:00
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continue
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}
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2023-03-05 13:39:06 +01:00
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log.Info().Str("Mode", "TCP").Str("Incoming Address", conn.RemoteAddr().String()).Msg("Connection accepted")
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2023-01-28 19:30:56 +01:00
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go handleConnection(conn, forwardAddr)
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}
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2023-03-05 13:39:06 +01:00
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}
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2023-01-28 19:30:56 +01:00
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2023-03-05 13:39:06 +01:00
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func udpListen(la, forwardAddr string) {
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// Listen for incoming UDP packets on port 3000
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listenAddr, err := net.ResolveUDPAddr("udp", la)
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if err != nil {
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log.Err(err).Str("Mode", "UDP").Msg("Failed to resolve UDP listen address")
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return
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}
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listener, err := net.ListenUDP("udp", listenAddr)
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if err != nil {
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log.Err(err).Str("Mode", "UDP").Msg("Failed to listen on UDP port")
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return
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}
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defer listener.Close()
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log.Info().Str("Mode", "UDP").Str("Listen Address", listenAddr.String()).Msg("Listening")
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// Forward incoming UDP packets to another host and port
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remoteAddr, err := net.ResolveUDPAddr("udp", forwardAddr)
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if err != nil {
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log.Err(err).Str("Mode", "UDP").Msg("Failed to resolve remote address")
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return
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}
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var (
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callerAddr *net.UDPAddr
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sendAddr *net.UDPAddr
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)
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buf := make([]byte, 2048)
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for {
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n, addr, err := listener.ReadFromUDP(buf)
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if err != nil {
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log.Err(err).Str("Mode", "UDP").Msg("Failed to read from UDP connection")
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continue
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}
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if callerAddr == nil {
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callerAddr = addr
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}
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if addr.String() == remoteAddr.String() {
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sendAddr = callerAddr
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} else {
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sendAddr = remoteAddr
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callerAddr = addr
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}
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//log.Info().Str("Mode", "UDP").Str("Incoming Address", addr.String()).Str("Forward Address", sendAddr.String()).Msg("Packet received")
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_, err = listener.WriteToUDP(buf[:n], sendAddr)
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if err != nil {
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log.Err(err).Str("Mode", "udp").Msg("Failed to write to UDP connection")
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continue
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}
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}
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2023-01-28 19:30:56 +01:00
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}
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func handleConnection(conn net.Conn, forwardAddr string) {
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defer conn.Close()
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fwrd, err := net.Dial("tcp", forwardAddr)
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if err != nil {
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2023-03-05 13:39:06 +01:00
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log.Err(err).Str("Mode", "TCP").Msg("Failed to connect to forward address")
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2023-01-28 19:30:56 +01:00
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return
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}
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var wg sync.WaitGroup
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wg.Add(2)
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go func() {
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defer fwrd.Close()
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defer wg.Done()
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_, err := io.Copy(fwrd, conn)
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if err != nil {
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2023-03-05 13:39:06 +01:00
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log.Err(err).Str("Mode", "TCP").Msg("Failed to copy from connection to forward address")
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2023-01-28 19:30:56 +01:00
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}
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}()
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go func() {
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defer conn.Close()
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defer wg.Done()
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_, err := io.Copy(conn, fwrd)
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if err != nil {
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2023-03-05 13:39:06 +01:00
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log.Err(err).Str("Mode", "TCP").Msg("Failed to copy from forward address to connection")
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2023-01-28 19:30:56 +01:00
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}
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}()
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wg.Wait()
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2023-03-05 13:39:06 +01:00
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log.Info().Str("Mode", "TCP").Str("Incoming Address", conn.RemoteAddr().String()).Msg("Connection closed")
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2023-01-28 19:30:56 +01:00
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}
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