From 7c2e938684b205c39310a41f9d9356d517867c2d Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Tue, 15 Dec 2020 15:20:13 +0700
Subject: [PATCH] trace when a packet is dropped because the receivedPackets
 chan is full

---
 session.go      |  3 +++
 session_test.go | 14 +++++++++-----
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/session.go b/session.go
index afc9e8bd3..68a6cecca 100644
--- a/session.go
+++ b/session.go
@@ -1117,6 +1117,9 @@ func (s *session) handlePacket(p *receivedPacket) {
 	select {
 	case s.receivedPackets <- p:
 	default:
+		if s.tracer != nil {
+			s.tracer.DroppedPacket(logging.PacketTypeNotDetermined, p.Size(), logging.PacketDropDOSPrevention)
+		}
 	}
 }
 
diff --git a/session_test.go b/session_test.go
index 09c513d61..18df9a871 100644
--- a/session_test.go
+++ b/session_test.go
@@ -2092,13 +2092,17 @@ var _ = Describe("Session", func() {
 		})
 	})
 
-	It("stores up to MaxSessionUnprocessedPackets packets", func(done Done) {
+	It("stores up to MaxSessionUnprocessedPackets packets", func() {
+		done := make(chan struct{})
+		tracer.EXPECT().DroppedPacket(logging.PacketTypeNotDetermined, logging.ByteCount(6), logging.PacketDropDOSPrevention).Do(func(logging.PacketType, logging.ByteCount, logging.PacketDropReason) {
+			close(done)
+		})
 		// Nothing here should block
-		for i := protocol.PacketNumber(0); i < protocol.MaxSessionUnprocessedPackets+10; i++ {
-			sess.handlePacket(&receivedPacket{})
+		for i := protocol.PacketNumber(0); i < protocol.MaxSessionUnprocessedPackets+1; i++ {
+			sess.handlePacket(&receivedPacket{data: []byte("foobar")})
 		}
-		close(done)
-	}, 0.5)
+		Eventually(done).Should(BeClosed())
+	})
 
 	Context("getting streams", func() {
 		It("opens streams", func() {