rudp/proxy/proxy.go

   1 /*
   2 Proxy is a Minetest RUDP proxy server
   3 supporting multiple concurrent connections.
   4
   5 Usage:
   6         proxy dial:port listen:port
   7 where dial:port is the server address
   8 and listen:port is the address to listen on.
   9 */
  10 package main
  11
  12 import (
  13         "errors"
  14         "fmt"
  15         "log"
  16         "net"
  17         "os"
  18
  19         "mt/rudp"
  20 )
  21
  22 func main() {
  23         if len(os.Args) != 3 {
  24                 fmt.Fprintln(os.Stderr, "usage: proxy dial:port listen:port")
  25                 os.Exit(1)
  26         }
  27
  28         srvaddr, err := net.ResolveUDPAddr("udp", os.Args[1])
  29         if err != nil {
  30                 log.Fatal(err)
  31         }
  32
  33         lc, err := net.ListenPacket("udp", os.Args[2])
  34         if err != nil {
  35                 log.Fatal(err)
  36         }
  37         defer lc.Close()
  38
  39         l := rudp.Listen(lc)
  40         for {
  41                 clt, err := l.Accept()
  42                 if err != nil {
  43                         log.Print(err)
  44                         continue
  45                 }
  46
  47                 log.Print(clt.Addr(), " connected")
  48
  49                 conn, err := net.DialUDP("udp", nil, srvaddr)
  50                 if err != nil {
  51                         log.Print(err)
  52                         continue
  53                 }
  54                 srv := rudp.Connect(conn, conn.RemoteAddr())
  55
  56                 go proxy(clt, srv)
  57                 go proxy(srv, clt)
  58         }
  59 }
  60
  61 func proxy(src, dest *rudp.Peer) {
  62         for {
  63                 pkt, err := src.Recv()
  64                 if err != nil {
  65                         if errors.Is(err, net.ErrClosed) {
  66                                 msg := src.Addr().String() + " disconnected"
  67                                 if src.TimedOut() {
  68                                         msg += " (timed out)"
  69                                 }
  70                                 log.Print(msg)
  71
  72                                 break
  73                         }
  74
  75                         log.Print(err)
  76                         continue
  77                 }
  78
  79                 if _, err := dest.Send(pkt); err != nil {
  80                         log.Print(err)
  81                 }
  82         }
  83
  84         dest.SendDisco(0, true)
  85         dest.Close()
  86 }