implement a session method to tell if the handshake is already complete

session.go

@@ -137,6 +137,8 @@ type session struct {
 
 	ctx                context.Context
 	ctxCancel          context.CancelFunc
+	handshakeCtx       context.Context
+	handshakeCtxCancel context.CancelFunc
 
 	undecryptablePackets []*receivedPacket
 
@@ -356,6 +358,7 @@ func (s *session) postSetup() error {
 	s.sendingScheduled = make(chan struct{}, 1)
 	s.undecryptablePackets = make([]*receivedPacket, 0, protocol.MaxUndecryptablePackets)
 	s.ctx, s.ctxCancel = context.WithCancel(context.Background())
+	s.handshakeCtx, s.handshakeCtxCancel = context.WithCancel(context.Background())
 
 	s.timer = utils.NewTimer()
 	now := time.Now()
@@ -465,6 +468,10 @@ runLoop:
 	return closeErr.err
 }
 
+func (s *session) HandshakeComplete() context.Context {
+	return s.handshakeCtx
+}
+
 func (s *session) Context() context.Context {
 	return s.ctx
 }
@@ -505,6 +512,7 @@ func (s *session) idleTimeoutStartTime() time.Time {
 func (s *session) handleHandshakeComplete() {
 	s.handshakeComplete = true
 	s.handshakeCompleteChan = nil // prevent this case from ever being selected again
+	s.handshakeCtxCancel()
 	s.sessionRunner.OnHandshakeComplete(s)
 
 	// The client completes the handshake first (after sending the CFIN).

session_test.go

@@ -1153,6 +1153,48 @@ var _ = Describe("Session", func() {
 		})
 	})
 
+	It("cancels the HandshakeComplete context when the handshake completes", func() {
+		sessionRunner.EXPECT().OnHandshakeComplete(gomock.Any())
+		packer.EXPECT().PackPacket().AnyTimes()
+		finishHandshake := make(chan struct{})
+		go func() {
+			defer GinkgoRecover()
+			<-finishHandshake
+			cryptoSetup.EXPECT().RunHandshake()
+			close(sess.handshakeCompleteChan)
+			sess.run()
+		}()
+		handshakeCtx := sess.HandshakeComplete()
+		Consistently(handshakeCtx.Done()).ShouldNot(BeClosed())
+		close(finishHandshake)
+		Eventually(handshakeCtx.Done()).Should(BeClosed())
+		//make sure the go routine returns
+		streamManager.EXPECT().CloseWithError(gomock.Any())
+		sessionRunner.EXPECT().Retire(gomock.Any())
+		packer.EXPECT().PackConnectionClose(gomock.Any()).Return(&packedPacket{}, nil)
+		cryptoSetup.EXPECT().Close()
+		Expect(sess.Close()).To(Succeed())
+		Eventually(sess.Context().Done()).Should(BeClosed())
+	})
+
+	It("doesn't cancel the HandshakeComplete context when the handshake fails", func() {
+		packer.EXPECT().PackPacket().AnyTimes()
+		streamManager.EXPECT().CloseWithError(gomock.Any())
+		sessionRunner.EXPECT().Retire(gomock.Any())
+		packer.EXPECT().PackConnectionClose(gomock.Any()).Return(&packedPacket{}, nil)
+		cryptoSetup.EXPECT().Close()
+		go func() {
+			defer GinkgoRecover()
+			cryptoSetup.EXPECT().RunHandshake()
+			sess.run()
+		}()
+		handshakeCtx := sess.HandshakeComplete()
+		Consistently(handshakeCtx.Done()).ShouldNot(BeClosed())
+		sess.closeLocal(errors.New("handshake error"))
+		Consistently(handshakeCtx.Done()).ShouldNot(BeClosed())
+		Eventually(sess.Context().Done()).Should(BeClosed())
+	})
+
 	It("sends a 1-RTT packet when the handshake completes", func() {
 		done := make(chan struct{})
 		gomock.InOrder(