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sent_packet_history.go
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sent_packet_history.go
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package ackhandler
import (
"fmt"
"v2ray.com/core/external/github.com/lucas-clemente/quic-go/internal/protocol"
)
type sentPacketHistory struct {
packetList *PacketList
packetMap map[protocol.PacketNumber]*PacketElement
numOutstandingPackets int
numOutstandingCryptoPackets int
firstOutstanding *PacketElement
}
func newSentPacketHistory() *sentPacketHistory {
return &sentPacketHistory{
packetList: NewPacketList(),
packetMap: make(map[protocol.PacketNumber]*PacketElement),
}
}
func (h *sentPacketHistory) SentPacket(p *Packet) {
h.sentPacketImpl(p)
}
func (h *sentPacketHistory) sentPacketImpl(p *Packet) *PacketElement {
el := h.packetList.PushBack(*p)
h.packetMap[p.PacketNumber] = el
if h.firstOutstanding == nil {
h.firstOutstanding = el
}
if p.canBeRetransmitted {
h.numOutstandingPackets++
if p.EncryptionLevel != protocol.Encryption1RTT {
h.numOutstandingCryptoPackets++
}
}
return el
}
func (h *sentPacketHistory) SentPacketsAsRetransmission(packets []*Packet, retransmissionOf protocol.PacketNumber) {
retransmission, ok := h.packetMap[retransmissionOf]
// The retransmitted packet is not present anymore.
// This can happen if it was acked in between dequeueing of the retransmission and sending.
// Just treat the retransmissions as normal packets.
// TODO: This won't happen if we clear packets queued for retransmission on new ACKs.
if !ok {
for _, packet := range packets {
h.sentPacketImpl(packet)
}
return
}
retransmission.Value.retransmittedAs = make([]protocol.PacketNumber, len(packets))
for i, packet := range packets {
retransmission.Value.retransmittedAs[i] = packet.PacketNumber
el := h.sentPacketImpl(packet)
el.Value.isRetransmission = true
el.Value.retransmissionOf = retransmissionOf
}
}
func (h *sentPacketHistory) GetPacket(p protocol.PacketNumber) *Packet {
if el, ok := h.packetMap[p]; ok {
return &el.Value
}
return nil
}
// Iterate iterates through all packets.
// The callback must not modify the history.
func (h *sentPacketHistory) Iterate(cb func(*Packet) (cont bool, err error)) error {
cont := true
for el := h.packetList.Front(); cont && el != nil; el = el.Next() {
var err error
cont, err = cb(&el.Value)
if err != nil {
return err
}
}
return nil
}
// FirstOutStanding returns the first outstanding packet.
// It must not be modified (e.g. retransmitted).
// Use DequeueFirstPacketForRetransmission() to retransmit it.
func (h *sentPacketHistory) FirstOutstanding() *Packet {
if h.firstOutstanding == nil {
return nil
}
return &h.firstOutstanding.Value
}
// QueuePacketForRetransmission marks a packet for retransmission.
// A packet can only be queued once.
func (h *sentPacketHistory) MarkCannotBeRetransmitted(pn protocol.PacketNumber) error {
el, ok := h.packetMap[pn]
if !ok {
return fmt.Errorf("sent packet history: packet %d not found", pn)
}
if el.Value.canBeRetransmitted {
h.numOutstandingPackets--
if h.numOutstandingPackets < 0 {
panic("numOutstandingHandshakePackets negative")
}
if el.Value.EncryptionLevel != protocol.Encryption1RTT {
h.numOutstandingCryptoPackets--
if h.numOutstandingCryptoPackets < 0 {
panic("numOutstandingHandshakePackets negative")
}
}
}
el.Value.canBeRetransmitted = false
if el == h.firstOutstanding {
h.readjustFirstOutstanding()
}
return nil
}
// readjustFirstOutstanding readjusts the pointer to the first outstanding packet.
// This is necessary every time the first outstanding packet is deleted or retransmitted.
func (h *sentPacketHistory) readjustFirstOutstanding() {
el := h.firstOutstanding.Next()
for el != nil && !el.Value.canBeRetransmitted {
el = el.Next()
}
h.firstOutstanding = el
}
func (h *sentPacketHistory) Len() int {
return len(h.packetMap)
}
func (h *sentPacketHistory) Remove(p protocol.PacketNumber) error {
el, ok := h.packetMap[p]
if !ok {
return fmt.Errorf("packet %d not found in sent packet history", p)
}
if el == h.firstOutstanding {
h.readjustFirstOutstanding()
}
if el.Value.canBeRetransmitted {
h.numOutstandingPackets--
if h.numOutstandingPackets < 0 {
panic("numOutstandingHandshakePackets negative")
}
if el.Value.EncryptionLevel != protocol.Encryption1RTT {
h.numOutstandingCryptoPackets--
if h.numOutstandingCryptoPackets < 0 {
panic("numOutstandingHandshakePackets negative")
}
}
}
h.packetList.Remove(el)
delete(h.packetMap, p)
return nil
}
func (h *sentPacketHistory) HasOutstandingPackets() bool {
return h.numOutstandingPackets > 0
}
func (h *sentPacketHistory) HasOutstandingCryptoPackets() bool {
return h.numOutstandingCryptoPackets > 0
}