handshake: initiate the first key update after 100 packets

integrationtests/self/key_update_test.go

@@ -51,12 +51,14 @@ func (t *keyUpdateConnTracer) ReceivedShortHeaderPacket(hdr *logging.ShortHeader
 }
 
 var _ = Describe("Key Update tests", func() {
-	var server quic.Listener
+	It("downloads a large file", func() {
+		origKeyUpdateInterval := handshake.KeyUpdateInterval
+		defer func() { handshake.KeyUpdateInterval = origKeyUpdateInterval }()
+		handshake.KeyUpdateInterval = 1 // update keys as frequently as possible
 
-	runServer := func() {
+		server, err := quic.ListenAddr("localhost:0", getTLSConfig(), nil)
-		var err error
-		server, err = quic.ListenAddr("localhost:0", getTLSConfig(), nil)
 		Expect(err).ToNot(HaveOccurred())
+		defer server.Close()
 
 		go func() {
 			defer GinkgoRecover()
@@ -68,14 +70,7 @@ var _ = Describe("Key Update tests", func() {
 			_, err = str.Write(PRDataLong)
 			Expect(err).ToNot(HaveOccurred())
 		}()
-	}
 
-	It("downloads a large file", func() {
-		origKeyUpdateInterval := handshake.KeyUpdateInterval
-		defer func() { handshake.KeyUpdateInterval = origKeyUpdateInterval }()
-		handshake.KeyUpdateInterval = 1 // update keys as frequently as possible
-
-		runServer()
 		conn, err := quic.DialAddr(
 			fmt.Sprintf("localhost:%d", server.Addr().(*net.UDPAddr).Port),
 			getTLSClientConfig(),

internal/handshake/updatable_aead.go

@@ -19,6 +19,10 @@ import (
 // It's a package-level variable to allow modifying it for testing purposes.
 var KeyUpdateInterval uint64 = protocol.KeyUpdateInterval
 
+// FirstKeyUpdateInterval is the maximum number of packets we send or receive before initiating the first key update.
+// It's a package-level variable to allow modifying it for testing purposes.
+var FirstKeyUpdateInterval uint64 = 100
+
 type updatableAEAD struct {
 	suite *qtls.CipherSuiteTLS13
 
@@ -284,6 +288,12 @@ func (a *updatableAEAD) shouldInitiateKeyUpdate() bool {
 	if !a.updateAllowed() {
 		return false
 	}
+	// Initiate the first key update shortly after the handshake, in order to exercise the key update mechanism.
+	if a.keyPhase == 0 {
+		if a.numRcvdWithCurrentKey >= FirstKeyUpdateInterval || a.numSentWithCurrentKey >= FirstKeyUpdateInterval {
+			return true
+		}
+	}
 	if a.numRcvdWithCurrentKey >= KeyUpdateInterval {
 		a.logger.Debugf("Received %d packets with current key phase. Initiating key update to the next key phase: %d", a.numRcvdWithCurrentKey, a.keyPhase+1)
 		return true

internal/handshake/updatable_aead_test.go

@@ -282,21 +282,25 @@ var _ = Describe("Updatable AEAD", func() {
 							})
 
 							Context("initiating key updates", func() {
+								const firstKeyUpdateInterval = 5
 								const keyUpdateInterval = 20
-								var origKeyUpdateInterval uint64
+								var origKeyUpdateInterval, origFirstKeyUpdateInterval uint64
 
 								BeforeEach(func() {
 									origKeyUpdateInterval = KeyUpdateInterval
+									origFirstKeyUpdateInterval = FirstKeyUpdateInterval
 									KeyUpdateInterval = keyUpdateInterval
+									FirstKeyUpdateInterval = firstKeyUpdateInterval
 									server.SetHandshakeConfirmed()
 								})
 
 								AfterEach(func() {
 									KeyUpdateInterval = origKeyUpdateInterval
+									FirstKeyUpdateInterval = origFirstKeyUpdateInterval
 								})
 
 								It("initiates a key update after sealing the maximum number of packets, for the first update", func() {
-									for i := 0; i < keyUpdateInterval; i++ {
+									for i := 0; i < firstKeyUpdateInterval; i++ {
 										pn := protocol.PacketNumber(i)
 										Expect(server.KeyPhase()).To(Equal(protocol.KeyPhaseZero))
 										server.Seal(nil, msg, pn, ad)
@@ -328,7 +332,7 @@ var _ = Describe("Updatable AEAD", func() {
 
 								It("errors if the peer acknowledges a packet sent in the next key phase using the old key phase", func() {
 									// First make sure that we update our keys.
-									for i := 0; i < keyUpdateInterval; i++ {
+									for i := 0; i < firstKeyUpdateInterval; i++ {
 										pn := protocol.PacketNumber(i)
 										Expect(server.KeyPhase()).To(Equal(protocol.KeyPhaseZero))
 										server.Seal(nil, msg, pn, ad)
@@ -336,7 +340,7 @@ var _ = Describe("Updatable AEAD", func() {
 									serverTracer.EXPECT().UpdatedKey(protocol.KeyPhase(1), false)
 									Expect(server.KeyPhase()).To(Equal(protocol.KeyPhaseOne))
 									// Now that our keys are updated, send a packet using the new keys.
-									const nextPN = keyUpdateInterval + 1
+									const nextPN = firstKeyUpdateInterval + 1
 									server.Seal(nil, msg, nextPN, ad)
 									// We haven't decrypted any packet in the new key phase yet.
 									// This means that the ACK must have been sent in the old key phase.
@@ -348,7 +352,7 @@ var _ = Describe("Updatable AEAD", func() {
 
 								It("doesn't error before actually sending a packet in the new key phase", func() {
 									// First make sure that we update our keys.
-									for i := 0; i < keyUpdateInterval; i++ {
+									for i := 0; i < firstKeyUpdateInterval; i++ {
 										pn := protocol.PacketNumber(i)
 										Expect(server.KeyPhase()).To(Equal(protocol.KeyPhaseZero))
 										server.Seal(nil, msg, pn, ad)
@@ -366,7 +370,7 @@ var _ = Describe("Updatable AEAD", func() {
 								})
 
 								It("initiates a key update after opening the maximum number of packets, for the first update", func() {
-									for i := 0; i < keyUpdateInterval; i++ {
+									for i := 0; i < firstKeyUpdateInterval; i++ {
 										pn := protocol.PacketNumber(i)
 										Expect(server.KeyPhase()).To(Equal(protocol.KeyPhaseZero))
 										encrypted := client.Seal(nil, msg, pn, ad)
@@ -399,7 +403,7 @@ var _ = Describe("Updatable AEAD", func() {
 
 								It("drops keys 3 PTOs after a key update", func() {
 									now := time.Now()
-									for i := 0; i < keyUpdateInterval; i++ {
+									for i := 0; i < firstKeyUpdateInterval; i++ {
 										pn := protocol.PacketNumber(i)
 										Expect(server.KeyPhase()).To(Equal(protocol.KeyPhaseZero))
 										server.Seal(nil, msg, pn, ad)
@@ -435,7 +439,7 @@ var _ = Describe("Updatable AEAD", func() {
 									data1 := client.Seal(nil, msg, 1, ad)
 									_, err := server.Open(nil, data1, now, 1, protocol.KeyPhaseZero, ad)
 									Expect(err).ToNot(HaveOccurred())
-									for i := 0; i < keyUpdateInterval; i++ {
+									for i := 0; i < firstKeyUpdateInterval; i++ {
 										pn := protocol.PacketNumber(i)
 										Expect(server.KeyPhase()).To(Equal(protocol.KeyPhaseZero))
 										server.Seal(nil, msg, pn, ad)
@@ -451,7 +455,7 @@ var _ = Describe("Updatable AEAD", func() {
 								})
 
 								It("drops keys early when the peer forces initiates a key update within the 3 PTO period", func() {
-									for i := 0; i < keyUpdateInterval; i++ {
+									for i := 0; i < firstKeyUpdateInterval; i++ {
 										pn := protocol.PacketNumber(i)
 										Expect(server.KeyPhase()).To(Equal(protocol.KeyPhaseZero))
 										server.Seal(nil, msg, pn, ad)
@@ -488,7 +492,7 @@ var _ = Describe("Updatable AEAD", func() {
 								It("drops keys early when we initiate another key update within the 3 PTO period", func() {
 									server.SetHandshakeConfirmed()
 									// send so many packets that we initiate the first key update
-									for i := 0; i < keyUpdateInterval; i++ {
+									for i := 0; i < firstKeyUpdateInterval; i++ {
 										pn := protocol.PacketNumber(i)
 										Expect(server.KeyPhase()).To(Equal(protocol.KeyPhaseZero))
 										server.Seal(nil, msg, pn, ad)

interop/client/main.go

@@ -88,7 +88,7 @@ func runTestcase(testcase string) error {
 	switch testcase {
 	case "handshake", "transfer", "retry":
 	case "keyupdate":
-		handshake.KeyUpdateInterval = 100
+		handshake.FirstKeyUpdateInterval = 100
 	case "chacha20":
 		tlsConf.CipherSuites = []uint16{tls.TLS_CHACHA20_POLY1305_SHA256}
 	case "multiconnect":