reuse single buffers

split up long conditionals

CHANGELOG.md

@@ -11,8 +11,41 @@ Before any major/minor/patch bump all unit tests will be run to verify they pass
 
 -   [x]
 
+## [0.6.0] - 2024-03-21
+
+### Added
+
+-   new environment variable `Q3RCON_DEBUG` for enabling debug logging. Defaults to 0.
+-   rcon responses are now logged at debug level
+-   invalid responses (rcon and query) now logged
+
+### Changed
+
+-   All packet header checking methods moved into Session struct.
+
+### Fixed
+
+-   a bug causing the proxy not to send back query responses
+
+## [0.3.0] - 2024-03-08
+
+### Added
+
+-   outgoing rcon requests now logged at info level
+-   new environment variable `Q3RCON_HOST` for specifying which ip to bind the proxy to. Defaults to `0.0.0.0`.
+
+### Changed
+
+-   now using [logrus][logrus] package for logging.
+
+### Fixed
+
+-   a `slice bounds out of range` error due to query packets being logged.
+
 ## [0.1.0] - 2024-01-27
 
+### Added
+
 -   only forward packets if the header matches q3 rcon/query.
 
 ## [0.0.1] - 2024-01-27
@@ -20,3 +53,5 @@ Before any major/minor/patch bump all unit tests will be run to verify they pass
 ### Added
 
 -   All source files for lilproxy including full commit history.
+
+[logrus]: https://github.com/sirupsen/logrus

README.md

@@ -22,7 +22,7 @@ Avoid sending plaintext rcon commands to the public game server port. In general
 
 ### Special Thanks
 
-[Dylan][user_link] For writing this proxy.
+[Dylan][user_link] For writing [lilproxy][lilproxy_url].
 
 [lilproxy_url]: https://github.com/dgparker/lilproxy
 [user_link]: https://github.com/dgparker

debian/q3rcon-proxy.service

@@ -0,0 +1,18 @@
+[Unit]
+Description=Q3Rcon Proxy Service
+Wants=network.target
+After=network.target
+
+[Service]
+Type=simple
+User=gameservers
+Environment="Q3RCON_PROXY=20000:28960;20001:28961;20002:28962"
+Environment="Q3RCON_HOST=0.0.0.0"
+Environment="Q3RCON_DEBUG=0"
+
+ExecStart=/usr/local/bin/q3rcon-proxy
+Restart=always
+RestartSec=3
+
+[Install]
+WantedBy=multi-user.target

pkg/udpproxy/session.go

@@ -9,24 +9,27 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
-type Session struct {
+type session struct {
 	serverConn *net.UDPConn
 	proxyConn  *net.UDPConn
 	caddr      *net.UDPAddr
 	updateTime time.Time
+
+	validator
 }
 
-func newSession(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
 	}
 
-	session := &Session{
+	session := &session{
 		serverConn: serverConn,
 		proxyConn:  proxyConn,
 		caddr:      caddr,
 		updateTime: time.Now(),
+		validator:  newValidator(),
 	}
 
 	go session.listen()
@@ -34,25 +37,9 @@ func newSession(caddr *net.UDPAddr, raddr *net.UDPAddr, proxyConn *net.UDPConn)
 	return session, nil
 }
 
-func (s *Session) isRconPacket(buf []byte) bool {
-	return string(buf[:8]) == "\xff\xff\xff\xffrcon"
-}
-
-func (s *Session) isQueryPacket(buf []byte) bool {
-	return string(buf[:13]) == "\xff\xff\xff\xffgetstatus" || string(buf[:11]) == "\xff\xff\xff\xffgetinfo"
-}
-
-func (s *Session) isValidPacket(buf []byte) bool {
-	return s.isRconPacket(buf) || s.isQueryPacket(buf)
-}
-
-func (s *Session) isResponsePacket(buf []byte) bool {
-	return string(buf[:9]) == "\xff\xff\xff\xffprint"
-}
-
-func (s *Session) listen() error {
+func (s *session) listen() error {
+	buf := make([]byte, 2048)
 	for {
-		buf := make([]byte, 2048)
 		n, err := s.serverConn.Read(buf)
 		if err != nil {
 			log.Error(err)
@@ -63,9 +50,11 @@ func (s *Session) listen() error {
 	}
 }
 
-func (s *Session) proxyFrom(buf []byte) error {
-	if !s.isResponsePacket(buf) {
-		return nil
+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()
@@ -75,17 +64,20 @@ func (s *Session) proxyFrom(buf []byte) error {
 		return err
 	}
 
-	if log.GetLevel() == log.DebugLevel {
-		parts := strings.Split(string(buf[10:]), " ")
-		log.Debugf("Response: %s", strings.Join(parts, " "))
+	if s.isRconResponsePacket(buf) {
+		if s.isBadRconResponse(buf) {
+			log.Infof("Response: Bad rcon from %s", s.caddr.IP)
+		} else {
+			log.Debugf("Response: %s", string(buf[10:]))
+		}
 	}
 
 	return nil
 }
 
-func (s *Session) proxyTo(buf []byte) error {
-	if !s.isValidPacket(buf) {
-		err := errors.New("not a rcon or query packet")
+func (s *session) proxyTo(buf []byte) error {
+	if !s.isValidRequestPacket(buf) {
+		err := errors.New("not a rcon or query request packet")
 		log.Error(err.Error())
 		return err
 	}
@@ -97,9 +89,9 @@ func (s *Session) proxyTo(buf []byte) error {
 		return err
 	}
 
-	if s.isRconPacket(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:], " "))
+	if s.isRconRequestPacket(buf) {
+		parts := strings.SplitN(string(buf), " ", 3)
+		log.Infof("From [%s] To [%s] Command: %s", s.caddr.IP, s.serverConn.RemoteAddr(), parts[len(parts)-1])
 	}
 
 	return nil

pkg/udpproxy/udpproxy.go

@@ -15,7 +15,7 @@ type Client struct {
 	proxyConn *net.UDPConn
 
 	mutex    sync.RWMutex
-	sessions map[string]*Session
+	sessions map[string]*session
 }
 
 func New(port, target string) (*Client, error) {
@@ -33,7 +33,7 @@ func New(port, target string) (*Client, error) {
 		laddr:    laddr,
 		raddr:    raddr,
 		mutex:    sync.RWMutex{},
-		sessions: map[string]*Session{},
+		sessions: map[string]*session{},
 	}, nil
 }
 
@@ -46,8 +46,8 @@ func (c *Client) ListenAndServe() error {
 
 	go c.pruneSessions()
 
+	buf := make([]byte, 2048)
 	for {
-		buf := make([]byte, 2048)
 		n, caddr, err := c.proxyConn.ReadFromUDP(buf)
 		if err != nil {
 			log.Error(err)

pkg/udpproxy/validator.go

@@ -0,0 +1,59 @@
+package udpproxy
+
+import "bytes"
+
+type validator struct {
+	rconRequestHeader       []byte
+	getstatusRequestHeader  []byte
+	getinfoRequestHeader    []byte
+	rconResponseHeader      []byte
+	getstatusResponseHeader []byte
+	getinfoResponseHeader   []byte
+	badRconIdentifier       []byte
+}
+
+func newValidator() validator {
+	v := validator{}
+	v.rconRequestHeader = []byte("\xff\xff\xff\xffrcon")
+	v.getstatusRequestHeader = []byte("\xff\xff\xff\xffgetstatus")
+	v.getinfoRequestHeader = []byte("\xff\xff\xff\xffgetinfo")
+	v.rconResponseHeader = []byte("\xff\xff\xff\xffprint\n")
+	v.getstatusResponseHeader = []byte("\xff\xff\xff\xffstatusResponse\n")
+	v.getinfoResponseHeader = []byte("\xff\xff\xff\xffinfoResponse\n")
+	v.badRconIdentifier = []byte("Bad rcon")
+	return v
+}
+
+func (v *validator) compare(buf, c []byte) bool {
+	return bytes.Equal(buf[:len(c)], c)
+}
+
+func (v *validator) isRconRequestPacket(buf []byte) bool {
+	return v.compare(buf, v.rconRequestHeader)
+}
+
+func (v *validator) isQueryRequestPacket(buf []byte) bool {
+	return v.compare(buf, v.getstatusRequestHeader) ||
+		v.compare(buf, v.getinfoRequestHeader)
+}
+
+func (v *validator) isValidRequestPacket(buf []byte) bool {
+	return v.isRconRequestPacket(buf) || v.isQueryRequestPacket(buf)
+}
+
+func (v *validator) isRconResponsePacket(buf []byte) bool {
+	return v.compare(buf, v.rconResponseHeader)
+}
+
+func (v *validator) isQueryResponsePacket(buf []byte) bool {
+	return v.compare(buf, v.getstatusResponseHeader) ||
+		v.compare(buf, v.getinfoResponseHeader)
+}
+
+func (v *validator) isValidResponsePacket(buf []byte) bool {
+	return v.isRconResponsePacket(buf) || v.isQueryResponsePacket(buf)
+}
+
+func (v *validator) isBadRconResponse(buf []byte) bool {
+	return v.compare(buf[len(v.rconResponseHeader):], v.badRconIdentifier)
+}