mirror of
https://github.com/refraction-networking/uquic.git
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95575f5fe7
uTLS is not yet bumped to the new version, so this commit breaks the dependencies relationship by getting rid of the local replace.
119 lines
3.4 KiB
Go
119 lines
3.4 KiB
Go
package quic
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import (
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"net"
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"time"
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"github.com/refraction-networking/uquic/internal/ackhandler"
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"github.com/refraction-networking/uquic/internal/protocol"
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"github.com/refraction-networking/uquic/internal/utils"
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"github.com/refraction-networking/uquic/internal/wire"
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)
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type mtuDiscoverer interface {
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// Start starts the MTU discovery process.
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// It's unnecessary to call ShouldSendProbe before that.
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Start(maxPacketSize protocol.ByteCount)
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ShouldSendProbe(now time.Time) bool
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CurrentSize() protocol.ByteCount
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GetPing() (ping ackhandler.Frame, datagramSize protocol.ByteCount)
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}
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const (
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// At some point, we have to stop searching for a higher MTU.
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// We're happy to send a packet that's 10 bytes smaller than the actual MTU.
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maxMTUDiff = 20
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// send a probe packet every mtuProbeDelay RTTs
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mtuProbeDelay = 5
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)
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func getMaxPacketSize(addr net.Addr) protocol.ByteCount {
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maxSize := protocol.ByteCount(protocol.MinInitialPacketSize)
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// If this is not a UDP address, we don't know anything about the MTU.
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// Use the minimum size of an Initial packet as the max packet size.
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if udpAddr, ok := addr.(*net.UDPAddr); ok {
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if utils.IsIPv4(udpAddr.IP) {
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maxSize = protocol.InitialPacketSizeIPv4
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} else {
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maxSize = protocol.InitialPacketSizeIPv6
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}
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}
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return maxSize
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}
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type mtuFinder struct {
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lastProbeTime time.Time
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mtuIncreased func(protocol.ByteCount)
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rttStats *utils.RTTStats
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inFlight protocol.ByteCount // the size of the probe packet currently in flight. InvalidByteCount if none is in flight
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current protocol.ByteCount
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max protocol.ByteCount // the maximum value, as advertised by the peer (or our maximum size buffer)
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}
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var _ mtuDiscoverer = &mtuFinder{}
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func newMTUDiscoverer(rttStats *utils.RTTStats, start protocol.ByteCount, mtuIncreased func(protocol.ByteCount)) *mtuFinder {
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return &mtuFinder{
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inFlight: protocol.InvalidByteCount,
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current: start,
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rttStats: rttStats,
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mtuIncreased: mtuIncreased,
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}
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}
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func (f *mtuFinder) done() bool {
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return f.max-f.current <= maxMTUDiff+1
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}
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func (f *mtuFinder) Start(maxPacketSize protocol.ByteCount) {
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f.lastProbeTime = time.Now() // makes sure the first probe packet is not sent immediately
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f.max = maxPacketSize
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}
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func (f *mtuFinder) ShouldSendProbe(now time.Time) bool {
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if f.max == 0 || f.lastProbeTime.IsZero() {
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return false
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}
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if f.inFlight != protocol.InvalidByteCount || f.done() {
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return false
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}
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return !now.Before(f.lastProbeTime.Add(mtuProbeDelay * f.rttStats.SmoothedRTT()))
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}
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func (f *mtuFinder) GetPing() (ackhandler.Frame, protocol.ByteCount) {
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size := (f.max + f.current) / 2
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f.lastProbeTime = time.Now()
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f.inFlight = size
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return ackhandler.Frame{
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Frame: &wire.PingFrame{},
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Handler: (*mtuFinderAckHandler)(f),
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}, size
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}
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func (f *mtuFinder) CurrentSize() protocol.ByteCount {
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return f.current
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}
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type mtuFinderAckHandler mtuFinder
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var _ ackhandler.FrameHandler = &mtuFinderAckHandler{}
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func (h *mtuFinderAckHandler) OnAcked(wire.Frame) {
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size := h.inFlight
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if size == protocol.InvalidByteCount {
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panic("OnAcked callback called although there's no MTU probe packet in flight")
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}
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h.inFlight = protocol.InvalidByteCount
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h.current = size
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h.mtuIncreased(size)
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}
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func (h *mtuFinderAckHandler) OnLost(wire.Frame) {
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size := h.inFlight
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if size == protocol.InvalidByteCount {
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panic("OnLost callback called although there's no MTU probe packet in flight")
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}
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h.max = size
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h.inFlight = protocol.InvalidByteCount
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}
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