gr1ffon/quic-go
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use varint packet numbers in IETF QUIC headers

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This commit is contained in:
Marten Seemann
2018-06-03 16:41:54 +08:00
parent bd6fd979a4
commit 3e03055a7d
17 changed files with 316 additions and 263 deletions
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26
internal/protocol/packet_number.go
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@@ -1,8 +1,25 @@
package protocol
// InferPacketNumber calculates the packet number based on the received packet number, its length and the last seen packet number
func InferPacketNumber(packetNumberLength PacketNumberLen, lastPacketNumber PacketNumber, wirePacketNumber PacketNumber) PacketNumber {
epochDelta := PacketNumber(1) << (uint8(packetNumberLength) * 8)
func InferPacketNumber(
packetNumberLength PacketNumberLen,
lastPacketNumber PacketNumber,
wirePacketNumber PacketNumber,
version VersionNumber,
) PacketNumber {
var epochDelta PacketNumber
if version.UsesVarintPacketNumbers() {
switch packetNumberLength {
case PacketNumberLen1:
epochDelta = PacketNumber(1) << 7
case PacketNumberLen2:
epochDelta = PacketNumber(1) << 14
case PacketNumberLen4:
epochDelta = PacketNumber(1) << 30
}
} else {
epochDelta = PacketNumber(1) << (uint8(packetNumberLength) * 8)
}
epoch := lastPacketNumber & ^(epochDelta - 1)
prevEpochBegin := epoch - epochDelta
nextEpochBegin := epoch + epochDelta
@@ -29,9 +46,10 @@ func delta(a, b PacketNumber) PacketNumber {
// GetPacketNumberLengthForHeader gets the length of the packet number for the public header
// it never chooses a PacketNumberLen of 1 byte, since this is too short under certain circumstances
func GetPacketNumberLengthForHeader(packetNumber PacketNumber, leastUnacked PacketNumber) PacketNumberLen {
func GetPacketNumberLengthForHeader(packetNumber, leastUnacked PacketNumber, version VersionNumber) PacketNumberLen {
diff := uint64(packetNumber - leastUnacked)
if diff < (1 << (uint8(PacketNumberLen2)*8 - 1)) {
if version.UsesVarintPacketNumbers() && diff < (1<<(14-1)) ||
!version.UsesVarintPacketNumbers() && diff < (1<<(16-1)) {
return PacketNumberLen2
}
return PacketNumberLen4