Use a single socket for relaying

listener.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	syncthingprotocol "github.com/syncthing/protocol"
+	"github.com/syncthing/syncthing/lib/tlsutil"
 
 	"github.com/syncthing/relaysrv/protocol"
 )
@@ -21,14 +22,16 @@ var (
 	numConnections int64
 )
 
-func protocolListener(addr string, config *tls.Config) {
+func listener(addr string, config *tls.Config) {
-	listener, err := net.Listen("tcp", addr)
+	tcpListener, err := net.Listen("tcp", addr)
 	if err != nil {
 		log.Fatalln(err)
 	}
 
+	listener := tlsutil.DowngradingListener{tcpListener, nil}
+
 	for {
-		conn, err := listener.Accept()
+		conn, isTLS, err := listener.AcceptNoWrap()
 		if err != nil {
 			if debug {
 				log.Println(err)
@@ -39,10 +42,15 @@ func protocolListener(addr string, config *tls.Config) {
 		setTCPOptions(conn)
 
 		if debug {
-			log.Println("Protocol listener accepted connection from", conn.RemoteAddr())
+			log.Println("Listener accepted connection from", conn.RemoteAddr(), "tls", isTLS)
 		}
 
+		if isTLS {
 			go protocolConnectionHandler(conn, config)
+		} else {
+			go sessionConnectionHandler(conn)
+		}
+
 	}
 }
 
@@ -220,6 +228,65 @@ func protocolConnectionHandler(tcpConn net.Conn, config *tls.Config) {
 	}
 }
 
+func sessionConnectionHandler(conn net.Conn) {
+	if err := conn.SetDeadline(time.Now().Add(messageTimeout)); err != nil {
+		if debug {
+			log.Println("Weird error setting deadline:", err, "on", conn.RemoteAddr())
+		}
+		return
+	}
+
+	message, err := protocol.ReadMessage(conn)
+	if err != nil {
+		return
+	}
+
+	switch msg := message.(type) {
+	case protocol.JoinSessionRequest:
+		ses := findSession(string(msg.Key))
+		if debug {
+			log.Println(conn.RemoteAddr(), "session lookup", ses)
+		}
+
+		if ses == nil {
+			protocol.WriteMessage(conn, protocol.ResponseNotFound)
+			conn.Close()
+			return
+		}
+
+		if !ses.AddConnection(conn) {
+			if debug {
+				log.Println("Failed to add", conn.RemoteAddr(), "to session", ses)
+			}
+			protocol.WriteMessage(conn, protocol.ResponseAlreadyConnected)
+			conn.Close()
+			return
+		}
+
+		if err := protocol.WriteMessage(conn, protocol.ResponseSuccess); err != nil {
+			if debug {
+				log.Println("Failed to send session join response to ", conn.RemoteAddr(), "for", ses)
+			}
+			return
+		}
+
+		if err := conn.SetDeadline(time.Time{}); err != nil {
+			if debug {
+				log.Println("Weird error setting deadline:", err, "on", conn.RemoteAddr())
+			}
+			conn.Close()
+			return
+		}
+
+	default:
+		if debug {
+			log.Println("Unexpected message from", conn.RemoteAddr(), message)
+		}
+		protocol.WriteMessage(conn, protocol.ResponseUnexpectedMessage)
+		conn.Close()
+	}
+}
+
 func messageReader(conn net.Conn, messages chan<- interface{}, errors chan<- error) {
 	atomic.AddInt64(&numConnections, 1)
 	defer atomic.AddInt64(&numConnections, -1)

main.go

@@ -17,8 +17,7 @@ import (
 )
 
 var (
-	listenProtocol string
+	listen string
-	listenSession  string
 	debug  bool
 
 	sessionAddress []byte
@@ -39,9 +38,7 @@ var (
 func main() {
 	var dir, extAddress string
 
-	flag.StringVar(&listenProtocol, "protocol-listen", ":22067", "Protocol listen address")
+	flag.StringVar(&listen, "listen", ":22067", "Protocol listen address")
-	flag.StringVar(&listenSession, "session-listen", ":22068", "Session listen address")
-	flag.StringVar(&extAddress, "external-address", "", "External address to advertise, defaults no IP and session-listen port, causing clients to use the remote IP from the protocol connection")
 	flag.StringVar(&dir, "keys", ".", "Directory where cert.pem and key.pem is stored")
 	flag.DurationVar(&networkTimeout, "network-timeout", 2*time.Minute, "Timeout for network operations")
 	flag.DurationVar(&pingInterval, "ping-interval", time.Minute, "How often pings are sent")
@@ -54,7 +51,7 @@ func main() {
 	flag.Parse()
 
 	if extAddress == "" {
-		extAddress = listenSession
+		extAddress = listen
 	}
 
 	addr, err := net.ResolveTCPAddr("tcp", extAddress)
@@ -100,11 +97,9 @@ func main() {
 		globalLimiter = ratelimit.NewBucketWithRate(float64(globalLimitBps), int64(2*globalLimitBps))
 	}
 
-	go sessionListener(listenSession)
-
 	if statusAddr != "" {
 		go statusService(statusAddr)
 	}
 
-	protocolListener(listenProtocol, tlsCfg)
+	listener(listen, tlsCfg)
 }

protocol/packets.go

@@ -7,8 +7,9 @@ package protocol
 
 import (
 	"fmt"
-	syncthingprotocol "github.com/syncthing/protocol"
 	"net"
+
+	syncthingprotocol "github.com/syncthing/protocol"
 )
 
 const (

session_listener.go

@@ -1,95 +0,0 @@
-// Copyright (C) 2015 Audrius Butkevicius and Contributors (see the CONTRIBUTORS file).
-
-package main
-
-import (
-	"log"
-	"net"
-	"time"
-
-	"github.com/syncthing/relaysrv/protocol"
-)
-
-func sessionListener(addr string) {
-	listener, err := net.Listen("tcp", addr)
-	if err != nil {
-		log.Fatalln(err)
-	}
-
-	for {
-		conn, err := listener.Accept()
-		if err != nil {
-			if debug {
-				log.Println(err)
-			}
-			continue
-		}
-
-		setTCPOptions(conn)
-
-		if debug {
-			log.Println("Session listener accepted connection from", conn.RemoteAddr())
-		}
-
-		go sessionConnectionHandler(conn)
-	}
-}
-
-func sessionConnectionHandler(conn net.Conn) {
-	if err := conn.SetDeadline(time.Now().Add(messageTimeout)); err != nil {
-		if debug {
-			log.Println("Weird error setting deadline:", err, "on", conn.RemoteAddr())
-		}
-		return
-	}
-
-	message, err := protocol.ReadMessage(conn)
-	if err != nil {
-		return
-	}
-
-	switch msg := message.(type) {
-	case protocol.JoinSessionRequest:
-		ses := findSession(string(msg.Key))
-		if debug {
-			log.Println(conn.RemoteAddr(), "session lookup", ses)
-		}
-
-		if ses == nil {
-			protocol.WriteMessage(conn, protocol.ResponseNotFound)
-			conn.Close()
-			return
-		}
-
-		if !ses.AddConnection(conn) {
-			if debug {
-				log.Println("Failed to add", conn.RemoteAddr(), "to session", ses)
-			}
-			protocol.WriteMessage(conn, protocol.ResponseAlreadyConnected)
-			conn.Close()
-			return
-		}
-
-		if err := protocol.WriteMessage(conn, protocol.ResponseSuccess); err != nil {
-			if debug {
-				log.Println("Failed to send session join response to ", conn.RemoteAddr(), "for", ses)
-			}
-			return
-		}
-
-		if err := conn.SetDeadline(time.Time{}); err != nil {
-			if debug {
-				log.Println("Weird error setting deadline:", err, "on", conn.RemoteAddr())
-			}
-			conn.Close()
-			return
-		}
-
-	default:
-		if debug {
-			log.Println("Unexpected message from", conn.RemoteAddr(), message)
-		}
-		protocol.WriteMessage(conn, protocol.ResponseUnexpectedMessage)
-		conn.Close()
-	}
-}