implement issuing and retiring of connection IDs

conn_id_generator_test.go

@@ -0,0 +1,95 @@
+package quic
+
+import (
+	"github.com/lucas-clemente/quic-go/internal/protocol"
+	"github.com/lucas-clemente/quic-go/internal/wire"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("Connection ID Generator", func() {
+	var (
+		addedConnIDs   []protocol.ConnectionID
+		retiredConnIDs []protocol.ConnectionID
+		queuedFrames   []wire.Frame
+		g              *connIDGenerator
+	)
+
+	BeforeEach(func() {
+		addedConnIDs = nil
+		retiredConnIDs = nil
+		queuedFrames = nil
+		g = newConnIDGenerator(
+			protocol.ConnectionID{1, 2, 3, 4, 5, 6, 7},
+			func(c protocol.ConnectionID) [16]byte {
+				addedConnIDs = append(addedConnIDs, c)
+				l := uint8(len(addedConnIDs))
+				return [16]byte{l, l, l, l, l, l, l, l, l, l, l, l, l, l, l, l}
+			},
+			func(c protocol.ConnectionID) { retiredConnIDs = append(retiredConnIDs, c) },
+			func(f wire.Frame) { queuedFrames = append(queuedFrames, f) },
+		)
+	})
+
+	It("issues new connection IDs", func() {
+		Expect(g.SetMaxActiveConnIDs(4)).To(Succeed())
+		Expect(retiredConnIDs).To(BeEmpty())
+		Expect(addedConnIDs).To(HaveLen(4))
+		for i := 0; i < len(addedConnIDs)-1; i++ {
+			Expect(addedConnIDs[i]).ToNot(Equal(addedConnIDs[i+1]))
+		}
+		Expect(queuedFrames).To(HaveLen(4))
+		for i := 0; i < 4; i++ {
+			f := queuedFrames[i]
+			Expect(f).To(BeAssignableToTypeOf(&wire.NewConnectionIDFrame{}))
+			nf := f.(*wire.NewConnectionIDFrame)
+			Expect(nf.SequenceNumber).To(BeEquivalentTo(i + 1))
+			Expect(nf.ConnectionID.Len()).To(Equal(7))
+			j := uint8(i + 1)
+			Expect(nf.StatelessResetToken).To(Equal([16]byte{j, j, j, j, j, j, j, j, j, j, j, j, j, j, j, j}))
+		}
+	})
+
+	It("limits the number of connection IDs that it issues", func() {
+		Expect(g.SetMaxActiveConnIDs(9999999)).To(Succeed())
+		Expect(retiredConnIDs).To(BeEmpty())
+		Expect(addedConnIDs).To(HaveLen(protocol.MaxIssuedConnectionIDs))
+		Expect(queuedFrames).To(HaveLen(protocol.MaxIssuedConnectionIDs))
+	})
+
+	It("errors if the peers tries to retire a connection ID that wasn't yet issued", func() {
+		Expect(g.Retire(1)).To(MatchError("PROTOCOL_VIOLATION: tried to retire connection ID 1. Highest issued: 0"))
+	})
+
+	It("issues new connection IDs, when old ones are retired", func() {
+		Expect(g.SetMaxActiveConnIDs(5)).To(Succeed())
+		queuedFrames = nil
+		Expect(retiredConnIDs).To(BeEmpty())
+		Expect(g.Retire(3)).To(Succeed())
+		Expect(queuedFrames).To(HaveLen(1))
+		Expect(queuedFrames[0]).To(BeAssignableToTypeOf(&wire.NewConnectionIDFrame{}))
+		nf := queuedFrames[0].(*wire.NewConnectionIDFrame)
+		Expect(nf.SequenceNumber).To(BeEquivalentTo(6))
+		Expect(nf.ConnectionID.Len()).To(Equal(7))
+	})
+
+	It("retires the initial connection ID", func() {
+		Expect(g.Retire(0)).To(Succeed())
+		Expect(retiredConnIDs).To(HaveLen(1))
+		Expect(retiredConnIDs[0]).To(Equal(protocol.ConnectionID{1, 2, 3, 4, 5, 6, 7}))
+		Expect(addedConnIDs).To(BeEmpty())
+	})
+
+	It("handles duplicate retirements", func() {
+		Expect(g.SetMaxActiveConnIDs(11)).To(Succeed())
+		queuedFrames = nil
+		Expect(retiredConnIDs).To(BeEmpty())
+		Expect(g.Retire(5)).To(Succeed())
+		Expect(retiredConnIDs).To(HaveLen(1))
+		Expect(queuedFrames).To(HaveLen(1))
+		Expect(g.Retire(5)).To(Succeed())
+		Expect(retiredConnIDs).To(HaveLen(1))
+		Expect(queuedFrames).To(HaveLen(1))
+	})
+})