224 lines
7.2 KiB
Go
224 lines
7.2 KiB
Go
package protocol
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import (
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"fmt"
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"math"
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. "github.com/onsi/ginkgo"
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. "github.com/onsi/gomega"
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)
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// Tests taken and extended from chrome
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var _ = Describe("packet number calculation", func() {
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Context("infering a packet number", func() {
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check := func(length PacketNumberLen, expected, last uint64) {
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epoch := uint64(1) << (length * 8)
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epochMask := epoch - 1
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wirePacketNumber := expected & epochMask
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Expect(InferPacketNumber(length, PacketNumber(last), PacketNumber(wirePacketNumber))).To(Equal(PacketNumber(expected)))
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}
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for _, length := range []PacketNumberLen{PacketNumberLen1, PacketNumberLen2, PacketNumberLen4, PacketNumberLen6} {
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Context(fmt.Sprintf("with %d bytes", length), func() {
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epoch := uint64(1) << (length * 8)
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epochMask := epoch - 1
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It("works near epoch start", func() {
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// A few quick manual sanity check
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check(length, 1, 0)
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check(length, epoch+1, epochMask)
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check(length, epoch, epochMask)
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// Cases where the last number was close to the start of the range.
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for last := uint64(0); last < 10; last++ {
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// Small numbers should not wrap (even if they're out of order).
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for j := uint64(0); j < 10; j++ {
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check(length, j, last)
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}
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// Large numbers should not wrap either (because we're near 0 already).
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for j := uint64(0); j < 10; j++ {
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check(length, epoch-1-j, last)
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}
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}
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})
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It("works near epoch end", func() {
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// Cases where the last number was close to the end of the range
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for i := uint64(0); i < 10; i++ {
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last := epoch - i
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// Small numbers should wrap.
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for j := uint64(0); j < 10; j++ {
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check(length, epoch+j, last)
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}
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// Large numbers should not (even if they're out of order).
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for j := uint64(0); j < 10; j++ {
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check(length, epoch-1-j, last)
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}
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}
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})
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// Next check where we're in a non-zero epoch to verify we handle
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// reverse wrapping, too.
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It("works near previous epoch", func() {
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prevEpoch := 1 * epoch
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curEpoch := 2 * epoch
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// Cases where the last number was close to the start of the range
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for i := uint64(0); i < 10; i++ {
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last := curEpoch + i
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// Small number should not wrap (even if they're out of order).
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for j := uint64(0); j < 10; j++ {
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check(length, curEpoch+j, last)
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}
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// But large numbers should reverse wrap.
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for j := uint64(0); j < 10; j++ {
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num := epoch - 1 - j
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check(length, prevEpoch+num, last)
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}
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}
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})
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It("works near next epoch", func() {
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curEpoch := 2 * epoch
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nextEpoch := 3 * epoch
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// Cases where the last number was close to the end of the range
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for i := uint64(0); i < 10; i++ {
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last := nextEpoch - 1 - i
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// Small numbers should wrap.
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for j := uint64(0); j < 10; j++ {
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check(length, nextEpoch+j, last)
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}
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// but large numbers should not (even if they're out of order).
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for j := uint64(0); j < 10; j++ {
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num := epoch - 1 - j
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check(length, curEpoch+num, last)
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}
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}
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})
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It("works near next max", func() {
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maxNumber := uint64(math.MaxUint64)
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maxEpoch := maxNumber & ^epochMask
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// Cases where the last number was close to the end of the range
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for i := uint64(0); i < 10; i++ {
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// Subtract 1, because the expected next packet number is 1 more than the
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// last packet number.
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last := maxNumber - i - 1
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// Small numbers should not wrap, because they have nowhere to go.
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for j := uint64(0); j < 10; j++ {
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check(length, maxEpoch+j, last)
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}
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// Large numbers should not wrap either.
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for j := uint64(0); j < 10; j++ {
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num := epoch - 1 - j
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check(length, maxEpoch+num, last)
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}
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}
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})
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})
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}
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})
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Context("shortening a packet number for the publicHeader", func() {
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Context("shortening", func() {
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It("sends out low packet numbers as 2 byte", func() {
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length := GetPacketNumberLengthForHeader(4, 2)
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Expect(length).To(Equal(PacketNumberLen2))
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})
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It("sends out high packet numbers as 2 byte, if all ACKs are received", func() {
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length := GetPacketNumberLengthForHeader(0xDEADBEEF, 0xDEADBEEF-1)
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Expect(length).To(Equal(PacketNumberLen2))
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})
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It("sends out higher packet numbers as 4 bytes, if a lot of ACKs are missing", func() {
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length := GetPacketNumberLengthForHeader(40000, 2)
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Expect(length).To(Equal(PacketNumberLen4))
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})
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})
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Context("self-consistency", func() {
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It("works for small packet numbers", func() {
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for i := uint64(1); i < 10000; i++ {
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packetNumber := PacketNumber(i)
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leastUnacked := PacketNumber(1)
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length := GetPacketNumberLengthForHeader(packetNumber, leastUnacked)
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wirePacketNumber := (uint64(packetNumber) << (64 - length*8)) >> (64 - length*8)
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inferedPacketNumber := InferPacketNumber(length, leastUnacked, PacketNumber(wirePacketNumber))
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Expect(inferedPacketNumber).To(Equal(packetNumber))
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}
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})
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It("works for small packet numbers and increasing ACKed packets", func() {
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for i := uint64(1); i < 10000; i++ {
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packetNumber := PacketNumber(i)
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leastUnacked := PacketNumber(i / 2)
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length := GetPacketNumberLengthForHeader(packetNumber, leastUnacked)
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wirePacketNumber := (uint64(packetNumber) << (64 - length*8)) >> (64 - length*8)
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inferedPacketNumber := InferPacketNumber(length, leastUnacked, PacketNumber(wirePacketNumber))
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Expect(inferedPacketNumber).To(Equal(packetNumber))
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}
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})
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It("also works for larger packet numbers", func() {
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increment := uint64(1 << (8 - 3))
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for i := uint64(1); i < (2 << 31); i += increment {
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packetNumber := PacketNumber(i)
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leastUnacked := PacketNumber(1)
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length := GetPacketNumberLengthForHeader(packetNumber, leastUnacked)
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wirePacketNumber := (uint64(packetNumber) << (64 - length*8)) >> (64 - length*8)
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inferedPacketNumber := InferPacketNumber(length, leastUnacked, PacketNumber(wirePacketNumber))
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Expect(inferedPacketNumber).To(Equal(packetNumber))
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switch length {
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case PacketNumberLen2:
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increment = 1 << (2*8 - 3)
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case PacketNumberLen4:
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increment = 1 << (4*8 - 3)
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}
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}
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})
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It("works for packet numbers larger than 2^48", func() {
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for i := (uint64(1) << 48); i < ((uint64(1) << 63) - 1); i += (uint64(1) << 48) {
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packetNumber := PacketNumber(i)
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leastUnacked := PacketNumber(i - 1000)
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length := GetPacketNumberLengthForHeader(packetNumber, leastUnacked)
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wirePacketNumber := (uint64(packetNumber) << (64 - length*8)) >> (64 - length*8)
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inferedPacketNumber := InferPacketNumber(length, leastUnacked, PacketNumber(wirePacketNumber))
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Expect(inferedPacketNumber).To(Equal(packetNumber))
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}
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})
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})
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})
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Context("determining the minimum length of a packet number", func() {
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It("1 byte", func() {
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Expect(GetPacketNumberLength(0xFF)).To(Equal(PacketNumberLen1))
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})
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It("2 byte", func() {
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Expect(GetPacketNumberLength(0xFFFF)).To(Equal(PacketNumberLen2))
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})
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It("4 byte", func() {
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Expect(GetPacketNumberLength(0xFFFFFFFF)).To(Equal(PacketNumberLen4))
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})
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It("6 byte", func() {
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Expect(GetPacketNumberLength(0xFFFFFFFFFFFF)).To(Equal(PacketNumberLen6))
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})
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})
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})
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