From 74c9bd60314462c19ac5c4eaa54462adcf06b18c Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Wed, 15 Apr 2020 10:00:20 +0700
Subject: [PATCH] qlog the supported versions of a version negotiation packet

---
 qlog/event.go     | 13 ++++++++++++-
 qlog/qlog.go      |  7 ++++++-
 qlog/qlog_test.go |  6 ++++--
 3 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/qlog/event.go b/qlog/event.go
index 883664093..b77076789 100644
--- a/qlog/event.go
+++ b/qlog/event.go
@@ -47,6 +47,15 @@ func (e event) MarshalJSONArray(enc *gojay.Encoder) {
 	enc.Object(e.eventDetails)
 }
 
+type versions []versionNumber
+
+func (v versions) IsNil() bool { return false }
+func (v versions) MarshalJSONArray(enc *gojay.Encoder) {
+	for _, e := range v {
+		enc.AddString(e.String())
+	}
+}
+
 type eventConnectionStarted struct {
 	SrcAddr  *net.UDPAddr
 	DestAddr *net.UDPAddr
@@ -141,7 +150,8 @@ func (e eventRetryReceived) MarshalJSONObject(enc *gojay.Encoder) {
 }
 
 type eventVersionNegotiationReceived struct {
-	Header packetHeader
+	Header            packetHeader
+	SupportedVersions []versionNumber
 }
 
 func (e eventVersionNegotiationReceived) Category() category { return categoryTransport }
@@ -151,6 +161,7 @@ func (e eventVersionNegotiationReceived) IsNil() bool        { return false }
 func (e eventVersionNegotiationReceived) MarshalJSONObject(enc *gojay.Encoder) {
 	enc.StringKey("packet_type", PacketTypeVersionNegotiation.String())
 	enc.ObjectKey("header", e.Header)
+	enc.ArrayKey("supported_versions", versions(e.SupportedVersions))
 }
 
 type eventStatelessResetReceived struct {
diff --git a/qlog/qlog.go b/qlog/qlog.go
index 5475a2489..9276b070c 100644
--- a/qlog/qlog.go
+++ b/qlog/qlog.go
@@ -232,9 +232,14 @@ func (t *tracer) ReceivedRetry(hdr *wire.Header) {
 }
 
 func (t *tracer) ReceivedVersionNegotiationPacket(hdr *wire.Header) {
+	versions := make([]versionNumber, len(hdr.SupportedVersions))
+	for i, v := range hdr.SupportedVersions {
+		versions[i] = versionNumber(v)
+	}
 	t.mutex.Lock()
 	t.recordEvent(time.Now(), &eventVersionNegotiationReceived{
-		Header: *transformHeader(hdr),
+		Header:            *transformHeader(hdr),
+		SupportedVersions: versions,
 	})
 	t.mutex.Unlock()
 }
diff --git a/qlog/qlog_test.go b/qlog/qlog_test.go
index 96cd86658..ccf8083aa 100644
--- a/qlog/qlog_test.go
+++ b/qlog/qlog_test.go
@@ -328,7 +328,7 @@ var _ = Describe("Tracer", func() {
 					Type:              protocol.PacketTypeRetry,
 					DestConnectionID:  protocol.ConnectionID{1, 2, 3, 4, 5, 6, 7, 8},
 					SrcConnectionID:   protocol.ConnectionID{4, 3, 2, 1},
-					SupportedVersions: []protocol.VersionNumber{13, 37},
+					SupportedVersions: []protocol.VersionNumber{0xdeadbeef, 0xdecafbad},
 				},
 			)
 			entry := exportAndParseSingle()
@@ -338,12 +338,14 @@ var _ = Describe("Tracer", func() {
 			ev := entry.Event
 			Expect(ev).To(HaveKeyWithValue("packet_type", "version_negotiation"))
 			Expect(ev).To(HaveKey("header"))
+			Expect(ev).ToNot(HaveKey("frames"))
+			Expect(ev).To(HaveKey("supported_versions"))
+			Expect(ev["supported_versions"].([]interface{})).To(Equal([]interface{}{"deadbeef", "decafbad"}))
 			header := ev["header"]
 			Expect(header).ToNot(HaveKey("packet_number"))
 			Expect(header).ToNot(HaveKey("version"))
 			Expect(header).To(HaveKey("dcid"))
 			Expect(header).To(HaveKey("scid"))
-			Expect(ev).ToNot(HaveKey("frames"))
 		})
 
 		It("records a received Retry packet", func() {