rudp/cmd/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         "github.com/anon55555/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         pc, err := net.ListenPacket("udp", os.Args[2])
  29         if err != nil {
  30                 log.Fatal(err)
  31         }
  32         defer pc.Close()
  33
  34         l := rudp.Listen(pc)
  35         for {
  36                 clt, err := l.Accept()
  37                 if err != nil {
  38                         log.Print("accept: ", err)
  39                         continue
  40                 }
  41
  42                 log.Print(clt.ID(), ": connected")
  43
  44                 conn, err := net.Dial("udp", os.Args[1])
  45                 if err != nil {
  46                         log.Print(err)
  47                         continue
  48                 }
  49                 srv := rudp.Connect(conn)
  50
  51                 go proxy(clt, srv)
  52                 go proxy(srv, clt)
  53         }
  54 }
  55
  56 func proxy(src, dest *rudp.Conn) {
  57         s := fmt.Sprint(src.ID(), " (", src.RemoteAddr(), "): ")
  58
  59         for {
  60                 pkt, err := src.Recv()
  61                 if err != nil {
  62                         if errors.Is(err, net.ErrClosed) {
  63                                 if err := src.WhyClosed(); err != nil {
  64                                         log.Print(s, "disconnected: ", err)
  65                                 } else {
  66                                         log.Print(s, "disconnected")
  67                                 }
  68                                 break
  69                         }
  70
  71                         log.Print(s, err)
  72                         continue
  73                 }
  74
  75                 dest.Send(pkt)
  76         }
  77
  78         dest.Close()
  79 }