From 93e387314131c3d511ced623af4ca186cde02561 Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Tue, 6 Oct 2020 15:05:26 +0700
Subject: [PATCH] qlog the key phase bit

---
 logging/interface.go       |  9 +++++++++
 qlog/packet_header.go      | 15 +++++++++++++++
 qlog/packet_header_test.go |  3 +++
 3 files changed, 27 insertions(+)

diff --git a/logging/interface.go b/logging/interface.go
index 24398d3ae..b0c41fb81 100644
--- a/logging/interface.go
+++ b/logging/interface.go
@@ -22,6 +22,8 @@ type (
 	EncryptionLevel = protocol.EncryptionLevel
 	// The KeyPhase is the key phase of the 1-RTT keys.
 	KeyPhase = protocol.KeyPhase
+	// The KeyPhaseBit is the value of the key phase bit of the 1-RTT packets.
+	KeyPhaseBit = protocol.KeyPhaseBit
 	// The PacketNumber is the packet number of a packet.
 	PacketNumber = protocol.PacketNumber
 	// The Perspective is the role of a QUIC endpoint (client or server).
@@ -53,6 +55,13 @@ type (
 	RTTStats = utils.RTTStats
 )
 
+const (
+	// KeyPhaseZero is key phase bit 0
+	KeyPhaseZero KeyPhaseBit = protocol.KeyPhaseZero
+	// KeyPhaseOne is key phase bit 1
+	KeyPhaseOne KeyPhaseBit = protocol.KeyPhaseOne
+)
+
 const (
 	// PerspectiveServer is used for a QUIC server
 	PerspectiveServer Perspective = protocol.PerspectiveServer
diff --git a/qlog/packet_header.go b/qlog/packet_header.go
index 8d324f029..0369bbfad 100644
--- a/qlog/packet_header.go
+++ b/qlog/packet_header.go
@@ -37,6 +37,9 @@ type packetHeader struct {
 	Version          logging.VersionNumber
 	SrcConnectionID  logging.ConnectionID
 	DestConnectionID logging.ConnectionID
+
+	hasKeyPhase bool
+	KeyPhaseBit logging.KeyPhaseBit
 }
 
 func transformHeader(hdr *wire.Header) *packetHeader {
@@ -52,6 +55,10 @@ func transformHeader(hdr *wire.Header) *packetHeader {
 func transformExtendedHeader(hdr *wire.ExtendedHeader) *packetHeader {
 	h := transformHeader(&hdr.Header)
 	h.PacketNumber = hdr.PacketNumber
+	if !hdr.IsLongHeader {
+		h.hasKeyPhase = true
+		h.KeyPhaseBit = hdr.KeyPhase
+	}
 	return h
 }
 
@@ -74,4 +81,12 @@ func (h packetHeader) MarshalJSONObject(enc *gojay.Encoder) {
 	if h.DestConnectionID.Len() > 0 {
 		enc.StringKey("dcid", connectionID(h.DestConnectionID).String())
 	}
+	if h.hasKeyPhase {
+		switch h.KeyPhaseBit {
+		case logging.KeyPhaseZero:
+			enc.StringKey("key_phase_bit", "0")
+		case logging.KeyPhaseOne:
+			enc.StringKey("key_phase_bit", "1")
+		}
+	}
 }
diff --git a/qlog/packet_header_test.go b/qlog/packet_header_test.go
index c6846e86a..fd7893eb5 100644
--- a/qlog/packet_header_test.go
+++ b/qlog/packet_header_test.go
@@ -38,6 +38,7 @@ var _ = Describe("Packet Header", func() {
 				map[string]interface{}{
 					"packet_number": 42,
 					"dcil":          0,
+					"key_phase_bit": "0",
 				},
 			)
 		})
@@ -108,11 +109,13 @@ var _ = Describe("Packet Header", func() {
 				&wire.ExtendedHeader{
 					PacketNumber: 42,
 					Header:       wire.Header{DestConnectionID: protocol.ConnectionID{0xde, 0xad, 0xbe, 0xef}},
+					KeyPhase:     protocol.KeyPhaseOne,
 				},
 				map[string]interface{}{
 					"packet_number": 42,
 					"dcil":          4,
 					"dcid":          "deadbeef",
+					"key_phase_bit": "1",
 				},
 			)
 		})