retire old connection IDs when the peers sends us too many new ones

conn_id_manager.go

@@ -3,6 +3,7 @@ package quic
 import (
 	"fmt"
 
+	"github.com/lucas-clemente/quic-go/internal/protocol"
 	"github.com/lucas-clemente/quic-go/internal/utils"
 	"github.com/lucas-clemente/quic-go/internal/wire"
 )
@@ -18,6 +19,20 @@ func newConnIDManager(queueControlFrame func(wire.Frame)) *connIDManager {
 }
 
 func (h *connIDManager) Add(f *wire.NewConnectionIDFrame) error {
+	if err := h.add(f); err != nil {
+		return err
+	}
+	if h.queue.Len() > protocol.MaxActiveConnectionIDs {
+		// delete the first connection ID in the queue
+		val := h.queue.Remove(h.queue.Front())
+		h.queueControlFrame(&wire.RetireConnectionIDFrame{
+			SequenceNumber: val.SequenceNumber,
+		})
+	}
+	return nil
+}
+
+func (h *connIDManager) add(f *wire.NewConnectionIDFrame) error {
 	var next *utils.NewConnectionIDElement
 	for el := h.queue.Front(); el != nil; el = next {
 		if el.Value.SequenceNumber >= f.RetirePriorTo {

conn_id_manager_test.go

@@ -117,4 +117,20 @@ var _ = Describe("Connection ID Manager", func() {
 		c, _ := get()
 		Expect(c).To(Equal(protocol.ConnectionID{3, 4, 5, 6}))
 	})
+
+	It("retires old connection IDs when the peer sends too many new ones", func() {
+		for i := uint8(0); i < protocol.MaxActiveConnectionIDs; i++ {
+			Expect(m.Add(&wire.NewConnectionIDFrame{
+				SequenceNumber: uint64(i),
+				ConnectionID:   protocol.ConnectionID{i, i, i, i},
+			})).To(Succeed())
+		}
+		Expect(frameQueue).To(BeEmpty())
+		Expect(m.Add(&wire.NewConnectionIDFrame{
+			SequenceNumber: protocol.MaxActiveConnectionIDs,
+			ConnectionID:   protocol.ConnectionID{1, 2, 3, 4},
+		})).To(Succeed())
+		Expect(frameQueue).To(HaveLen(1))
+		Expect(frameQueue[0].(*wire.RetireConnectionIDFrame).SequenceNumber).To(BeEquivalentTo(0))
+	})
 })