return packet handling and connection errors in Dial

client.go

@@ -14,8 +14,9 @@ import (
 )
 
 type client struct {
-	mutex               sync.Mutex
-	connStateChangeCond sync.Cond
+	mutex                    sync.Mutex
+	connStateChangeOrErrCond sync.Cond
+	listenErr                error
 
 	conn     connection
 	hostname string
@@ -55,7 +56,7 @@ func Dial(pconn net.PacketConn, remoteAddr net.Addr, host string, config *Config
 		version:      protocol.SupportedVersions[len(protocol.SupportedVersions)-1], // use the highest supported version by default
 	}
 
-	c.connStateChangeCond.L = &c.mutex
+	c.connStateChangeOrErrCond.L = &c.mutex
 
 	err = c.createNewSession(nil)
 	if err != nil {
@@ -67,16 +68,20 @@ func Dial(pconn net.PacketConn, remoteAddr net.Addr, host string, config *Config
 	go c.listen()
 
 	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
 	for {
+		if c.listenErr != nil {
+			return nil, c.listenErr
+		}
 		if c.config.ConnState != nil && c.connState >= ConnStateVersionNegotiated {
 			break
 		}
 		if c.config.ConnState == nil && c.connState == ConnStateForwardSecure {
 			break
 		}
-		c.connStateChangeCond.Wait()
+		c.connStateChangeOrErrCond.Wait()
 	}
-	c.mutex.Unlock()
 
 	return c.session, nil
 }
@@ -98,16 +103,20 @@ func DialAddr(hostname string, config *Config) (Session, error) {
 
 // Listen listens
 func (c *client) listen() {
+	var err error
+
 	for {
+		var n int
+		var addr net.Addr
 		data := getPacketBuffer()
 		data = data[:protocol.MaxPacketSize]
 
-		n, addr, err := c.conn.Read(data)
+		n, addr, err = c.conn.Read(data)
 		if err != nil {
 			if !strings.HasSuffix(err.Error(), "use of closed network connection") {
 				c.session.Close(err)
 			}
-			return
+			break
 		}
 		data = data[:n]
 
@@ -115,9 +124,14 @@ func (c *client) listen() {
 		if err != nil {
 			utils.Errorf("error handling packet: %s", err.Error())
 			c.session.Close(err)
-			return
+			break
 		}
 	}
+
+	c.mutex.Lock()
+	c.listenErr = err
+	c.connStateChangeOrErrCond.Signal()
+	c.mutex.Unlock()
 }
 
 func (c *client) handlePacket(remoteAddr net.Addr, packet []byte) error {
@@ -145,7 +159,7 @@ func (c *client) handlePacket(remoteAddr net.Addr, packet []byte) error {
 	if !hdr.VersionFlag && c.connState == ConnStateInitial {
 		c.mutex.Lock()
 		c.connState = ConnStateVersionNegotiated
-		c.connStateChangeCond.Signal()
+		c.connStateChangeOrErrCond.Signal()
 		c.mutex.Unlock()
 		if c.config.ConnState != nil {
 			go c.config.ConnState(c.session, ConnStateVersionNegotiated)

client_test.go

@@ -48,28 +48,44 @@ var _ = Describe("Client", func() {
 		}
 	})
 
-	It("creates a new client", func() {
-		packetConn.dataToRead = []byte{0x0, 0x1, 0x0}
-		var err error
-		sess, err := Dial(packetConn, addr, "quic.clemente.io:1337", config)
-		Expect(err).ToNot(HaveOccurred())
-		Expect(*(*[]protocol.VersionNumber)(unsafe.Pointer(reflect.ValueOf(sess.(*session).cryptoSetup).Elem().FieldByName("negotiatedVersions").UnsafeAddr()))).To(BeNil())
-		Expect(*(*string)(unsafe.Pointer(reflect.ValueOf(sess.(*session).cryptoSetup).Elem().FieldByName("hostname").UnsafeAddr()))).To(Equal("quic.clemente.io"))
-	})
-
-	// TODO: actually test this
-	// now we're only testing that Dial doesn't return directly after version negotiation
-	It("only returns once a forward-secure connection is established if no ConnState is defined", func() {
-		packetConn.dataToRead = []byte{0x0, 0x1, 0x0}
-		config.ConnState = nil
-		var dialReturned bool
-		go func() {
-			defer GinkgoRecover()
-			_, err := Dial(packetConn, addr, "quic.clemente.io:1337", config)
+	Context("Dialing", func() {
+		It("creates a new client", func() {
+			packetConn.dataToRead = []byte{0x0, 0x1, 0x0}
+			var err error
+			sess, err := Dial(packetConn, addr, "quic.clemente.io:1337", config)
 			Expect(err).ToNot(HaveOccurred())
-			dialReturned = true
-		}()
-		Consistently(func() bool { return dialReturned }).Should(BeFalse())
+			Expect(*(*[]protocol.VersionNumber)(unsafe.Pointer(reflect.ValueOf(sess.(*session).cryptoSetup).Elem().FieldByName("negotiatedVersions").UnsafeAddr()))).To(BeNil())
+			Expect(*(*string)(unsafe.Pointer(reflect.ValueOf(sess.(*session).cryptoSetup).Elem().FieldByName("hostname").UnsafeAddr()))).To(Equal("quic.clemente.io"))
+		})
+
+		It("errors when receiving an invalid first packet from the server", func() {
+			packetConn.dataToRead = []byte{0xff}
+			sess, err := Dial(packetConn, addr, "quic.clemente.io:1337", config)
+			Expect(err).To(HaveOccurred())
+			Expect(sess).To(BeNil())
+		})
+
+		It("errors when receiving an error from the connection", func() {
+			testErr := errors.New("connection error")
+			packetConn.readErr = testErr
+			_, err := Dial(packetConn, addr, "quic.clemente.io:1337", config)
+			Expect(err).To(MatchError(testErr))
+		})
+
+		// TODO: actually test this
+		// now we're only testing that Dial doesn't return directly after version negotiation
+		It("only returns once a forward-secure connection is established if no ConnState is defined", func() {
+			packetConn.dataToRead = []byte{0x0, 0x1, 0x0}
+			config.ConnState = nil
+			var dialReturned bool
+			go func() {
+				defer GinkgoRecover()
+				_, err := Dial(packetConn, addr, "quic.clemente.io:1337", config)
+				Expect(err).ToNot(HaveOccurred())
+				dialReturned = true
+			}()
+			Consistently(func() bool { return dialReturned }).Should(BeFalse())
+		})
 	})
 
 	It("errors on invalid public header", func() {