Make TCP read timeouts configurable.

This should be helpful on high-latency networks, like Tor or I2P.
Also gofmt.

src/yggdrasil/config/config.go

@@ -5,6 +5,7 @@ type NodeConfig struct {
 	Listen                      string   `comment:"Listen address for peer connections. Default is to listen for all\nTCP connections over IPv4 and IPv6 with a random port."`
 	AdminListen                 string   `comment:"Listen address for admin connections Default is to listen for local\nconnections either on TCP/9001 or a UNIX socket depending on your\nplatform. Use this value for yggdrasilctl -endpoint=X."`
 	Peers                       []string `comment:"List of connection strings for static peers in URI format, i.e.\ntcp://a.b.c.d:e or socks://a.b.c.d:e/f.g.h.i:j"`
+	ReadTimeout                 int32    `comment:"Read timeout for connections, specified in milliseconds. If less than 6000 and not negative, 6000 (the default) is used. If negative, reads won't time out."`
 	AllowedEncryptionPublicKeys []string `comment:"List of peer encryption public keys to allow or incoming TCP\nconnections from. If left empty/undefined then all connections\nwill be allowed by default."`
 	EncryptionPublicKey         string   `comment:"Your public encryption key. Your peers may ask you for this to put\ninto their AllowedEncryptionPublicKeys configuration."`
 	EncryptionPrivateKey        string   `comment:"Your private encryption key. DO NOT share this with anyone!"`

src/yggdrasil/core.go

@@ -97,7 +97,7 @@ func (c *Core) Start(nc *config.NodeConfig, log *log.Logger) error {
 	c.init(&boxPub, &boxPriv, &sigPub, &sigPriv)
 	c.admin.init(c, nc.AdminListen)
 
-	if err := c.tcp.init(c, nc.Listen); err != nil {
+	if err := c.tcp.init(c, nc.Listen, nc.ReadTimeout); err != nil {
 		c.log.Println("Failed to start TCP interface")
 		return err
 	}

src/yggdrasil/tcp.go

@@ -28,7 +28,8 @@ import (
 )
 
 const tcp_msgSize = 2048 + 65535 // TODO figure out what makes sense
-const tcp_timeout = 6 * time.Second
+const default_tcp_timeout = 6 * time.Second
+const tcp_ping_interval = (default_tcp_timeout * 2 / 3)
 
 // Wrapper function for non tcp/ip connections.
 func setNoDelay(c net.Conn, delay bool) {
@@ -42,6 +43,7 @@ func setNoDelay(c net.Conn, delay bool) {
 type tcpInterface struct {
 	core        *Core
 	serv        net.Listener
+	tcp_timeout time.Duration
 	mutex       sync.Mutex // Protecting the below
 	calls       map[string]struct{}
 	conns       map[tcpInfo](chan struct{})
@@ -72,9 +74,14 @@ func (iface *tcpInterface) connectSOCKS(socksaddr, peeraddr string) {
 }
 
 // Initializes the struct.
-func (iface *tcpInterface) init(core *Core, addr string) (err error) {
+func (iface *tcpInterface) init(core *Core, addr string, readTimeout int32) (err error) {
 	iface.core = core
 
+	iface.tcp_timeout = time.Duration(readTimeout) * time.Millisecond
+	if iface.tcp_timeout >= 0 && iface.tcp_timeout < default_tcp_timeout {
+		iface.tcp_timeout = default_tcp_timeout
+	}
+
 	iface.serv, err = net.Listen("tcp", addr)
 	if err == nil {
 		iface.calls = make(map[string]struct{})
@@ -113,7 +120,7 @@ func (iface *tcpInterface) call(saddr string, socksaddr *string) {
 			iface.calls[saddr] = struct{}{}
 			defer func() {
 				// Block new calls for a little while, to mitigate livelock scenarios
-				time.Sleep(tcp_timeout)
+				time.Sleep(default_tcp_timeout)
 				time.Sleep(time.Duration(rand.Intn(1000)) * time.Millisecond)
 				iface.mutex.Lock()
 				delete(iface.calls, saddr)
@@ -168,8 +175,9 @@ func (iface *tcpInterface) handler(sock net.Conn, incoming bool) {
 	if err != nil {
 		return
 	}
-	timeout := time.Now().Add(tcp_timeout)
-	sock.SetReadDeadline(timeout)
+	if iface.tcp_timeout > 0 {
+		sock.SetReadDeadline(time.Now().Add(iface.tcp_timeout))
+	}
 	_, err = sock.Read(metaBytes)
 	if err != nil {
 		return
@@ -254,7 +262,7 @@ func (iface *tcpInterface) handler(sock net.Conn, incoming bool) {
 			atomic.AddUint64(&p.bytesSent, uint64(len(tcp_msg)+len(msgLen)+len(msg)))
 			util_putBytes(msg)
 		}
-		timerInterval := tcp_timeout * 2 / 3
+		timerInterval := tcp_ping_interval
 		timer := time.NewTimer(timerInterval)
 		defer timer.Stop()
 		for {
@@ -321,8 +329,9 @@ func (iface *tcpInterface) reader(sock net.Conn, in func([]byte)) error {
 	bs := make([]byte, 2*tcp_msgSize)
 	frag := bs[:0]
 	for {
-		timeout := time.Now().Add(tcp_timeout)
-		sock.SetReadDeadline(timeout)
+		if iface.tcp_timeout > 0 {
+			sock.SetReadDeadline(time.Now().Add(iface.tcp_timeout))
+		}
 		n, err := sock.Read(bs[len(frag):])
 		if n > 0 {
 			frag = bs[:len(frag)+n]

src/yggdrasil/tun_linux.go

@@ -34,7 +34,7 @@ func (tun *tunDevice) setup(ifname string, iftapmode bool, addr string, mtu int)
 	// that the MTU gets rounded down to 65521 instead of causing a panic.
 	if iftapmode {
 		if tun.mtu > 65535-tun_ETHER_HEADER_LENGTH {
-			tun.mtu = 65535-tun_ETHER_HEADER_LENGTH
+			tun.mtu = 65535 - tun_ETHER_HEADER_LENGTH
 		}
 	}
 	// Friendly output