Only stringify rcon responses if debug enabled.

fixes bug relaying query responses

cmd/q3rcon-proxy/main.go

@@ -2,10 +2,12 @@ package main
 
 import (
 	"fmt"
-	"log"
 	"os"
+	"strconv"
 	"strings"
 
+	log "github.com/sirupsen/logrus"
+
 	"github.com/onyx-and-iris/q3rcon-proxy/pkg/udpproxy"
 )
 
@@ -29,6 +31,18 @@ var (
 	proxies, host string
 )
 
+func getenvInt(key string) (int, error) {
+	s := os.Getenv(key)
+	if s == "" {
+		return 0, nil
+	}
+	v, err := strconv.Atoi(s)
+	if err != nil {
+		return 0, err
+	}
+	return v, nil
+}
+
 func init() {
 	proxies = os.Getenv("Q3RCON_PROXY")
 	if proxies == "" {
@@ -39,6 +53,18 @@ func init() {
 	if host == "" {
 		host = "0.0.0.0"
 	}
+
+	debug, err := getenvInt("Q3RCON_DEBUG")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	if debug == 1 {
+		log.SetLevel(log.DebugLevel)
+	} else {
+		log.SetLevel(log.InfoLevel)
+	}
+
 }
 
 func main() {

pkg/udpproxy/session.go

@@ -1,6 +1,7 @@
 package udpproxy
 
 import (
+	"errors"
 	"net"
 	"strings"
 	"time"
@@ -15,7 +16,7 @@ type Session struct {
 	updateTime time.Time
 }
 
-func createSession(caddr *net.UDPAddr, raddr *net.UDPAddr, proxyConn *net.UDPConn) (*Session, error) {
+func newSession(caddr *net.UDPAddr, raddr *net.UDPAddr, proxyConn *net.UDPConn) (*Session, error) {
 	serverConn, err := net.DialUDP("udp", nil, raddr)
 	if err != nil {
 		return nil, err
@@ -33,12 +34,36 @@ func createSession(caddr *net.UDPAddr, raddr *net.UDPAddr, proxyConn *net.UDPCon
 	return session, nil
 }
 
+func (s *Session) isRconRequestPacket(buf []byte) bool {
+	return string(buf[:8]) == "\xff\xff\xff\xffrcon"
+}
+
+func (s *Session) isQueryRequestPacket(buf []byte) bool {
+	return string(buf[:13]) == "\xff\xff\xff\xffgetstatus" || string(buf[:11]) == "\xff\xff\xff\xffgetinfo"
+}
+
+func (s *Session) isValidRequestPacket(buf []byte) bool {
+	return s.isRconRequestPacket(buf) || s.isQueryRequestPacket(buf)
+}
+
+func (s *Session) isRconResponsePacket(buf []byte) bool {
+	return string(buf[:9]) == "\xff\xff\xff\xffprint"
+}
+
+func (s *Session) isQueryResponsePacket(buf []byte) bool {
+	return string(buf[:18]) == "\xff\xff\xff\xffstatusResponse" || string(buf[:16]) == "\xff\xff\xff\xffinfoResponse"
+}
+
+func (s *Session) isValidResponsePacket(buf []byte) bool {
+	return s.isRconResponsePacket(buf) || s.isQueryResponsePacket(buf)
+}
+
 func (s *Session) listen() error {
 	for {
 		buf := make([]byte, 2048)
 		n, err := s.serverConn.Read(buf)
 		if err != nil {
-			log.Println(err)
+			log.Error(err)
 			continue
 		}
 
@@ -47,28 +72,44 @@ func (s *Session) listen() error {
 }
 
 func (s *Session) proxyFrom(buf []byte) error {
+	if !s.isValidResponsePacket(buf) {
+		err := errors.New("not a rcon or query response packet")
+		log.Error(err.Error())
+		return err
+	}
+
 	s.updateTime = time.Now()
 	_, err := s.proxyConn.WriteToUDP(buf, s.caddr)
 	if err != nil {
-		log.Println(err)
+		log.Error(err)
 		return err
 	}
 
+	if s.isRconResponsePacket(buf) && log.GetLevel() == log.DebugLevel {
+		parts := strings.Split(string(buf[10:]), " ")
+		log.Debugf("Response: %s", strings.Join(parts, " "))
+	}
+
 	return nil
 }
 
 func (s *Session) proxyTo(buf []byte) error {
-	s.updateTime = time.Now()
+	if !s.isValidRequestPacket(buf) {
-	_, err := s.serverConn.Write(buf)
+		err := errors.New("not a rcon or query request packet")
-	if err != nil {
+		log.Error(err.Error())
-		log.Println(err)
 		return err
 	}
 
-	cmd := string(buf)
+	s.updateTime = time.Now()
-	if cmd[:8] == "\xff\xff\xff\xffrcon" {
+	_, err := s.serverConn.Write(buf)
-		parts := strings.Split(cmd, " ")
+	if err != nil {
-		log.Info("From [", s.caddr.IP, "] To [", s.serverConn.RemoteAddr().String(), "] Command: ", strings.Join(parts[2:], " "))
+		log.Error(err)
+		return err
+	}
+
+	if s.isRconRequestPacket(buf) {
+		parts := strings.Split(string(buf), " ")
+		log.Infof("From [%s] To [%s] Command: %s", s.caddr.IP.String(), s.serverConn.RemoteAddr().String(), strings.Join(parts[2:], " "))
 	}
 
 	return nil

pkg/udpproxy/udpproxy.go

@@ -37,10 +37,6 @@ func New(port, target string) (*Client, error) {
 	}, nil
 }
 
-func (c *Client) isValidPacket(header []byte) bool {
-	return string(header[:8]) == "\xff\xff\xff\xffrcon" || string(header[:13]) == "\xff\xff\xff\xffgetstatus" || string(header[:11]) == "\xff\xff\xff\xffgetinfo"
-}
-
 func (c *Client) ListenAndServe() error {
 	var err error
 	c.proxyConn, err = net.ListenUDP("udp", c.laddr)
@@ -54,18 +50,14 @@ func (c *Client) ListenAndServe() error {
 		buf := make([]byte, 2048)
 		n, caddr, err := c.proxyConn.ReadFromUDP(buf)
 		if err != nil {
-			log.Println(err)
+			log.Error(err)
-		}
-
-		if !c.isValidPacket(buf[:16]) {
-			continue
 		}
 
 		session, found := c.sessions[caddr.String()]
 		if !found {
-			session, err = createSession(caddr, c.raddr, c.proxyConn)
+			session, err = newSession(caddr, c.raddr, c.proxyConn)
 			if err != nil {
-				log.Println(err)
+				log.Error(err)
 				continue
 			}