isQueryResponsePacket() and isValidResponsePacket() added

fixes bug relaying query responses

cmd/q3rcon-proxy/main.go

@@ -28,7 +28,7 @@ func start(proxy string) {
 }
 
 var (
-	proxies, host, debug string
+	proxies, host string
 )
 
 func getenvInt(key string) (int, error) {

pkg/udpproxy/session.go

@@ -1,6 +1,7 @@
 package udpproxy
 
 import (
+	"errors"
 	"net"
 	"strings"
 	"time"
@@ -33,20 +34,36 @@ func newSession(caddr *net.UDPAddr, raddr *net.UDPAddr, proxyConn *net.UDPConn)
 	return session, nil
 }
 
-func (s *Session) isRconPacket(buf []byte) bool {
+func (s *Session) isRconRequestPacket(buf []byte) bool {
 	return string(buf[:8]) == "\xff\xff\xff\xffrcon"
 }
 
-func (s *Session) isResponsePacket(buf []byte) bool {
+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
 		}
 
@@ -55,14 +72,20 @@ func (s *Session) listen() error {
 }
 
 func (s *Session) proxyFrom(buf []byte) error {
-	s.updateTime = time.Now()
+	if !s.isValidResponsePacket(buf) {
-	_, err := s.proxyConn.WriteToUDP(buf, s.caddr)
+		err := errors.New("not a rcon or query response packet")
-	if err != nil {
+		log.Error(err.Error())
-		log.Println(err)
 		return err
 	}
 
-	if s.isResponsePacket(buf) {
+	s.updateTime = time.Now()
+	_, err := s.proxyConn.WriteToUDP(buf, s.caddr)
+	if err != nil {
+		log.Error(err)
+		return err
+	}
+
+	if s.isRconResponsePacket(buf) {
 		parts := strings.Split(string(buf[10:]), " ")
 		log.Debugf("Response: %s", strings.Join(parts, " "))
 	}
@@ -71,14 +94,20 @@ func (s *Session) proxyFrom(buf []byte) error {
 }
 
 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
 	}
 
-	if s.isRconPacket(buf) {
+	s.updateTime = time.Now()
+	_, err := s.serverConn.Write(buf)
+	if err != nil {
+		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:], " "))
 	}

pkg/udpproxy/udpproxy.go

@@ -37,18 +37,6 @@ func New(port, target string) (*Client, error) {
 	}, nil
 }
 
-func (c *Client) isRconPacket(buf []byte) bool {
-	return string(buf[:8]) == "\xff\xff\xff\xffrcon"
-}
-
-func (c *Client) isQueryPacket(buf []byte) bool {
-	return string(buf[:13]) == "\xff\xff\xff\xffgetstatus" || string(buf[:11]) == "\xff\xff\xff\xffgetinfo"
-}
-
-func (c *Client) isValidPacket(buf []byte) bool {
-	return c.isRconPacket(buf) || c.isQueryPacket(buf)
-}
-
 func (c *Client) ListenAndServe() error {
 	var err error
 	c.proxyConn, err = net.ListenUDP("udp", c.laddr)
@@ -62,18 +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[:n]) {
-			continue
 		}
 
 		session, found := c.sessions[caddr.String()]
 		if !found {
 			session, err = newSession(caddr, c.raddr, c.proxyConn)
 			if err != nil {
-				log.Println(err)
+				log.Error(err)
 				continue
 			}