Add high-level protocol (de)serialization

1 files changed, 86 insertions, 0 deletions

diff --git a/cmd/proxy/proxy.go b/cmd/proxy/proxy.go
new file mode 100644
index 0000000..33cc354
--- /dev/null
+++ b/cmd/proxy/proxy.go
@@ -0,0 +1,86 @@
+/*
+Proxy is a Minetest proxy server
+supporting multiple concurrent connections.
+
+Usage:
+	proxy dial:port listen:port
+where dial:port is the server address
+and listen:port is the address to listen on.
+*/
+package main
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"net"
+	"os"
+
+	"github.com/anon55555/mt"
+)
+
+func main() {
+	if len(os.Args) != 3 {
+		fmt.Fprintln(os.Stderr, "usage: proxy dial:port listen:port")
+		os.Exit(1)
+	}
+
+	srvaddr, err := net.ResolveUDPAddr("udp", os.Args[1])
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	lc, err := net.ListenPacket("udp", os.Args[2])
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer lc.Close()
+
+	l := mt.Listen(lc)
+	for {
+		clt, err := l.Accept()
+		if err != nil {
+			log.Print(err)
+			continue
+		}
+
+		log.Print(clt.RemoteAddr().String() + " connected")
+
+		conn, err := net.DialUDP("udp", nil, srvaddr)
+		if err != nil {
+			log.Print(err)
+			continue
+		}
+		srv := mt.Connect(conn)
+
+		go proxy(clt, srv)
+		go proxy(srv, clt)
+	}
+}
+
+func proxy(src, dest mt.Peer) {
+	s := fmt.Sprint(src.ID(), " (", src.RemoteAddr(), "): ")
+
+	for {
+		pkt, err := src.Recv()
+		if err != nil {
+			if errors.Is(err, net.ErrClosed) {
+				if err := src.WhyClosed(); err != nil {
+					log.Print(s, "disconnected: ", err)
+				} else {
+					log.Print(s, "disconnected")
+				}
+				break
+			}
+
+			log.Print(s, err)
+			continue
+		}
+
+		if _, err := dest.Send(pkt); err != nil {
+			log.Print(err)
+		}
+	}
+
+	dest.Close()
+}