1 files changed, 24 insertions, 1 deletions
diff --git a/src/ssl/test/runner/handshake_messages.go b/src/ssl/test/runner/handshake_messages.go
index f12ca1ac..ac52eed4 100644
--- a/src/ssl/test/runner/handshake_messages.go
+++ b/src/ssl/test/runner/handshake_messages.go
@@ -298,6 +298,7 @@ type clientHelloMsg struct {
 	pad                     int
 	compressedCertAlgs      []uint16
 	delegatedCredentials    bool
+	pqExperimentSignal      bool
 }
 
 func (m *clientHelloMsg) equal(i interface{}) bool {
@@ -352,7 +353,8 @@ func (m *clientHelloMsg) equal(i interface{}) bool {
 		m.emptyExtensions == m1.emptyExtensions &&
 		m.pad == m1.pad &&
 		eqUint16s(m.compressedCertAlgs, m1.compressedCertAlgs) &&
-		m.delegatedCredentials == m1.delegatedCredentials
+		m.delegatedCredentials == m1.delegatedCredentials &&
+		m.pqExperimentSignal == m1.pqExperimentSignal
 }
 
 func (m *clientHelloMsg) marshalKeyShares(bb *byteBuilder) {
@@ -598,6 +600,11 @@ func (m *clientHelloMsg) marshal() []byte {
 		extensions.addU16(extensionDelegatedCredentials)
 		extensions.addU16(0) // Length is always 0
 	}
+	if m.pqExperimentSignal {
+		extensions.addU16(extensionPQExperimentSignal)
+		extensions.addU16(0) // Length is always 0
+	}
+
 	// The PSK extension must be last. See https://tools.ietf.org/html/rfc8446#section-4.2.11
 	if len(m.pskIdentities) > 0 && !m.pskBinderFirst {
 		extensions.addU16(extensionPreSharedKey)
@@ -724,6 +731,7 @@ func (m *clientHelloMsg) unmarshal(data []byte) bool {
 	m.extendedMasterSecret = false
 	m.customExtension = ""
 	m.delegatedCredentials = false
+	m.pqExperimentSignal = false
 
 	if len(reader) == 0 {
 		// ClientHello is optionally followed by extension data
@@ -959,6 +967,11 @@ func (m *clientHelloMsg) unmarshal(data []byte) bool {
 				return false
 			}
 			m.delegatedCredentials = true
+		case extensionPQExperimentSignal:
+			if len(body) != 0 {
+				return false
+			}
+			m.pqExperimentSignal = true
 		}
 
 		if isGREASEValue(extension) {
@@ -1226,6 +1239,7 @@ type serverExtensions struct {
 	supportedCurves         []CurveID
 	quicTransportParams     []byte
 	serverNameAck           bool
+	pqExperimentSignal      bool
 }
 
 func (m *serverExtensions) marshal(extensions *byteBuilder) {
@@ -1360,6 +1374,10 @@ func (m *serverExtensions) marshal(extensions *byteBuilder) {
 		extensions.addU16(extensionServerName)
 		extensions.addU16(0) // zero length
 	}
+	if m.pqExperimentSignal {
+		extensions.addU16(extensionPQExperimentSignal)
+		extensions.addU16(0) // zero length
+	}
 }
 
 func (m *serverExtensions) unmarshal(data byteReader, version uint16) bool {
@@ -1468,6 +1486,11 @@ func (m *serverExtensions) unmarshal(data byteReader, version uint16) bool {
 				return false
 			}
 			m.hasEarlyData = true
+		case extensionPQExperimentSignal:
+			if len(body) != 0 {
+				return false
+			}
+			m.pqExperimentSignal = true
 		default:
 			// Unknown extensions are illegal from the server.
 			return false