From 2c033ad0e371c53533b18927ddd133be9fa9b5d2 Mon Sep 17 00:00:00 2001
From: ModEngineer <43882205+ModEngineer@users.noreply.github.com>
Date: Sun, 16 Oct 2022 17:34:01 -0500
Subject: [PATCH] Added a UDP listener to allow clients to search for ppl-utils
 servers

---
 go.mod    |  2 +-
 server.go | 41 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/go.mod b/go.mod
index 1618eb9..f937526 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,3 @@
-module github.com/jyaif/ppl-utils
+module github.com/pewpewlive/ppl-utils
 
 go 1.14
diff --git a/server.go b/server.go
index 1d54db6..35c2863 100644
--- a/server.go
+++ b/server.go
@@ -1,10 +1,12 @@
 package main
 
 import (
+	"bytes"
 	"encoding/json"
 	"errors"
 	"fmt"
 	"log"
+	"net"
 	"net/http"
 	"os"
 	"strings"
@@ -79,6 +81,42 @@ func getLevelManifest(w http.ResponseWriter, r *http.Request) {
 	w.Write(levelManifest)
 }
 
+func udp_server() {
+	local_addr, err := net.ResolveUDPAddr("udp4", ":9001")
+	if err != nil {
+		panic(err)
+	}
+	last_buf := make([]byte, 4)
+	for {
+		conn, err := net.ListenUDP("udp4", local_addr)
+		if err != nil {
+			log.Print(err)
+			conn.Close()
+			continue
+		}
+		buf := make([]byte, 4)
+		_, addr, err := conn.ReadFromUDP(buf)
+		if err != nil {
+			log.Print(err)
+			conn.Close()
+			continue
+		}
+		if bytes.Equal(last_buf, buf) {
+			log.Print("Dropping duplicate pings")
+			conn.Close()
+			continue
+		}
+		addr.Port = 9002
+		_, err = conn.WriteToUDP(buf, addr)
+		if err != nil {
+			log.Print(err)
+			conn.Close()
+			continue
+		}
+		conn.Close()
+	}
+}
+
 func main() {
 	// Serves the static files
 	fs := cacheControlWrapper(http.FileServer(http.Dir(GetDir())))
@@ -90,5 +128,8 @@ func main() {
 
 	log.Print("Starting server on port 9000")
 	log.Print("open http://localhost:9000/pewpew.html to run PewPew")
+
+	go udp_server()
+
 	log.Fatal(http.ListenAndServe(":9000", nil))
 }