From f35a32989cc1fc76dee43f775ad2803096ce07f7 Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Wed, 27 Nov 2019 19:22:48 +0700
Subject: [PATCH] enforce the active_connection_id_limit

---
 conn_id_manager.go           |  3 ++-
 conn_id_manager_test.go      | 21 +++++++--------------
 internal/qerr/error_codes.go |  3 +++
 3 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/conn_id_manager.go b/conn_id_manager.go
index 2fc10145..dcb36b96 100644
--- a/conn_id_manager.go
+++ b/conn_id_manager.go
@@ -7,6 +7,7 @@ import (
 	mrand "math/rand"
 
 	"github.com/lucas-clemente/quic-go/internal/protocol"
+	"github.com/lucas-clemente/quic-go/internal/qerr"
 	"github.com/lucas-clemente/quic-go/internal/utils"
 	"github.com/lucas-clemente/quic-go/internal/wire"
 )
@@ -57,7 +58,7 @@ func (h *connIDManager) Add(f *wire.NewConnectionIDFrame) error {
 		return err
 	}
 	if h.queue.Len() >= protocol.MaxActiveConnectionIDs {
-		h.updateConnectionID()
+		return qerr.ConnectionIDLimitError
 	}
 	return nil
 }
diff --git a/conn_id_manager_test.go b/conn_id_manager_test.go
index 66047f10..43754c8a 100644
--- a/conn_id_manager_test.go
+++ b/conn_id_manager_test.go
@@ -176,26 +176,19 @@ var _ = Describe("Connection ID Manager", func() {
 		Expect(frameQueue[0].(*wire.RetireConnectionIDFrame).SequenceNumber).To(BeEquivalentTo(4))
 	})
 
-	It("retires old connection IDs when the peer sends too many new ones", func() {
-		for i := uint8(1); i <= protocol.MaxActiveConnectionIDs; i++ {
+	It("errors when the peer sends too connection IDs", func() {
+		for i := uint8(1); i < protocol.MaxActiveConnectionIDs; i++ {
 			Expect(m.Add(&wire.NewConnectionIDFrame{
 				SequenceNumber:      uint64(i),
 				ConnectionID:        protocol.ConnectionID{i, i, i, i},
 				StatelessResetToken: [16]byte{i, i, i, i, i, i, i, i, i, i, i, i, i, i, i, i},
 			})).To(Succeed())
 		}
-		Expect(frameQueue).To(HaveLen(1))
-		Expect(frameQueue[0].(*wire.RetireConnectionIDFrame).SequenceNumber).To(BeZero())
-		Expect(retiredTokens).To(BeEmpty())
-		frameQueue = nil
 		Expect(m.Add(&wire.NewConnectionIDFrame{
-			SequenceNumber: protocol.MaxActiveConnectionIDs + 1,
-			ConnectionID:   protocol.ConnectionID{1, 2, 3, 4},
-		})).To(Succeed())
-		Expect(frameQueue).To(HaveLen(1))
-		Expect(frameQueue[0].(*wire.RetireConnectionIDFrame).SequenceNumber).To(BeEquivalentTo(1))
-		Expect(retiredTokens).To(HaveLen(1))
-		Expect(retiredTokens[0]).To(Equal([16]byte{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}))
+			SequenceNumber:      uint64(9999),
+			ConnectionID:        protocol.ConnectionID{1, 2, 3, 4},
+			StatelessResetToken: [16]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16},
+		})).To(MatchError("CONNECTION_ID_LIMIT_ERROR"))
 	})
 
 	It("initiates the first connection ID update as soon as possible", func() {
@@ -211,7 +204,7 @@ var _ = Describe("Connection ID Manager", func() {
 
 	It("initiates subsequent updates when enough packets are sent", func() {
 		var s uint8
-		for s = uint8(1); s <= protocol.MaxActiveConnectionIDs; s++ {
+		for s = uint8(1); s < protocol.MaxActiveConnectionIDs; s++ {
 			Expect(m.Add(&wire.NewConnectionIDFrame{
 				SequenceNumber:      uint64(s),
 				ConnectionID:        protocol.ConnectionID{s, s, s, s},
diff --git a/internal/qerr/error_codes.go b/internal/qerr/error_codes.go
index 4158fcdb..d9d669bf 100644
--- a/internal/qerr/error_codes.go
+++ b/internal/qerr/error_codes.go
@@ -20,6 +20,7 @@ const (
 	FinalSizeError          ErrorCode = 0x6
 	FrameEncodingError      ErrorCode = 0x7
 	TransportParameterError ErrorCode = 0x8
+	ConnectionIDLimitError  ErrorCode = 0x9
 	ProtocolViolation       ErrorCode = 0xa
 	CryptoBufferExceeded    ErrorCode = 0xd
 )
@@ -64,6 +65,8 @@ func (e ErrorCode) String() string {
 		return "FRAME_ENCODING_ERROR"
 	case TransportParameterError:
 		return "TRANSPORT_PARAMETER_ERROR"
+	case ConnectionIDLimitError:
+		return "CONNECTION_ID_LIMIT_ERROR"
 	case ProtocolViolation:
 		return "PROTOCOL_VIOLATION"
 	case CryptoBufferExceeded: