From eeab7a5fcab1d7d506f2375a37b51ae1a1d5457c Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Sat, 27 Oct 2018 12:10:01 +0700
Subject: [PATCH] allow the server to retransmit Initial packets

---
 session.go      |  2 +-
 session_test.go | 52 ++++++++++++++++++++++++-------------------------
 2 files changed, 27 insertions(+), 27 deletions(-)

diff --git a/session.go b/session.go
index ab9ce5844..7ea1c3979 100644
--- a/session.go
+++ b/session.go
@@ -1066,7 +1066,7 @@ func (s *session) maybeSendRetransmission() (bool, error) {
 		// Don't retransmit Initial packets if we already received a response.
 		// An Initial might have been retransmitted multiple times before we receive a response.
 		// As soon as we receive one response, we don't need to send any more Initials.
-		if s.receivedFirstPacket && retransmitPacket.PacketType == protocol.PacketTypeInitial {
+		if s.perspective == protocol.PerspectiveClient && s.receivedFirstPacket && retransmitPacket.PacketType == protocol.PacketTypeInitial {
 			s.logger.Debugf("Skipping retransmission of packet %d. Already received a response to an Initial.", retransmitPacket.PacketNumber)
 			continue
 		}
diff --git a/session_test.go b/session_test.go
index 7d5fe7723..132c673d5 100644
--- a/session_test.go
+++ b/session_test.go
@@ -776,32 +776,6 @@ var _ = Describe("Session", func() {
 			Expect(mconn.written).To(Receive(ContainSubstring("PRST")))
 		})
 
-		It("doesn't retransmit an Initial packet if it already received a response", func() {
-			unpacker := NewMockUnpacker(mockCtrl)
-			unpacker.EXPECT().Unpack(gomock.Any(), gomock.Any(), gomock.Any()).Return(&unpackedPacket{}, nil)
-			sess.unpacker = unpacker
-			sph := mockackhandler.NewMockSentPacketHandler(mockCtrl)
-			sph.EXPECT().GetPacketNumberLen(gomock.Any()).Return(protocol.PacketNumberLen2).AnyTimes()
-			sph.EXPECT().DequeuePacketForRetransmission().Return(&ackhandler.Packet{
-				PacketNumber: 10,
-				PacketType:   protocol.PacketTypeInitial,
-			})
-			sph.EXPECT().DequeuePacketForRetransmission()
-			rph := mockackhandler.NewMockReceivedPacketHandler(mockCtrl)
-			rph.EXPECT().ReceivedPacket(gomock.Any(), gomock.Any(), gomock.Any())
-			sess.receivedPacketHandler = rph
-			sess.sentPacketHandler = sph
-			err := sess.handlePacketImpl(&receivedPacket{
-				header: &wire.Header{},
-				data:   []byte{0},
-			})
-			Expect(err).ToNot(HaveOccurred())
-			Expect(sess.receivedFirstPacket).To(BeTrue())
-			sent, err := sess.maybeSendRetransmission()
-			Expect(err).NotTo(HaveOccurred())
-			Expect(sent).To(BeFalse())
-		})
-
 		It("sends a retransmission and a regular packet in the same run", func() {
 			packetToRetransmit := &ackhandler.Packet{
 				PacketNumber: 10,
@@ -1670,6 +1644,32 @@ var _ = Describe("Client Session", func() {
 		Eventually(sess.Context().Done()).Should(BeClosed())
 	})
 
+	It("doesn't retransmit an Initial packet if it already received a response", func() {
+		unpacker := NewMockUnpacker(mockCtrl)
+		unpacker.EXPECT().Unpack(gomock.Any(), gomock.Any(), gomock.Any()).Return(&unpackedPacket{}, nil)
+		sess.unpacker = unpacker
+		sph := mockackhandler.NewMockSentPacketHandler(mockCtrl)
+		sph.EXPECT().GetPacketNumberLen(gomock.Any()).Return(protocol.PacketNumberLen2).AnyTimes()
+		sph.EXPECT().DequeuePacketForRetransmission().Return(&ackhandler.Packet{
+			PacketNumber: 10,
+			PacketType:   protocol.PacketTypeInitial,
+		})
+		sph.EXPECT().DequeuePacketForRetransmission()
+		rph := mockackhandler.NewMockReceivedPacketHandler(mockCtrl)
+		rph.EXPECT().ReceivedPacket(gomock.Any(), gomock.Any(), gomock.Any())
+		sess.receivedPacketHandler = rph
+		sess.sentPacketHandler = sph
+		err := sess.handlePacketImpl(&receivedPacket{
+			header: &wire.Header{},
+			data:   []byte{0},
+		})
+		Expect(err).ToNot(HaveOccurred())
+		Expect(sess.receivedFirstPacket).To(BeTrue())
+		sent, err := sess.maybeSendRetransmission()
+		Expect(err).NotTo(HaveOccurred())
+		Expect(sent).To(BeFalse())
+	})
+
 	Context("receiving packets", func() {
 		var hdr *wire.Header