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tracking.go
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tracking.go
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// Internal structure indicating packets we have
// received
package minq
import (
"fmt"
"github.com/bifurcation/mint"
"time"
)
type packetData struct {
protected bool
nonAcks bool
pn uint64
t time.Time
acked2 bool
}
type recvdPackets struct {
log loggingFunction
initted bool
minReceived uint64
maxReceived uint64
minNotAcked2 uint64
packets map[uint64]*packetData
unacked bool // Are there packets we haven't generated an ACK for
}
func newRecvdPackets(log loggingFunction) *recvdPackets {
return &recvdPackets{
log, // loggingFunction
false, // initted
0, // minReceived
0, // maxReceived
0, // minNotAcked2
make(map[uint64]*packetData, 0), // packets
false, // unacked
}
}
func (p *recvdPackets) initialized() bool {
return p.initted
}
func (p *recvdPackets) init(pn uint64) {
p.log(logTypeAck, "Initializing received packet start=%x", pn)
p.initted = true
p.minReceived = pn
p.maxReceived = pn
p.minNotAcked2 = pn
}
func (p *recvdPackets) packetNotReceived(pn uint64) bool {
if pn < p.minReceived {
return false
}
_, found := p.packets[pn]
return !found
}
func (p *recvdPackets) packetSetReceived(pn uint64, protected bool, nonAcks bool) {
p.log(logTypeAck, "Setting packet received=%x", pn)
if pn > p.maxReceived {
p.maxReceived = pn
}
if pn < p.minNotAcked2 {
p.minNotAcked2 = pn
}
p.log(logTypeAck, "Setting packet received=%x", pn)
p.packets[pn] = &packetData{
protected,
nonAcks,
pn,
time.Now(),
false,
}
p.unacked = true
}
func (p *recvdPackets) packetSetAcked2(pn uint64) {
p.log(logTypeAck, "Setting packet acked2=%v", pn)
if pn >= p.minNotAcked2 {
pk, ok := p.packets[pn]
if ok {
pk.acked2 = true
}
}
}
func (r *ackRange) String() string {
return fmt.Sprintf("%x(%d)", r.lastPacket, r.count)
}
func (r *ackRanges) String() string {
rsp := ""
for _, s := range *r {
if rsp != "" {
rsp += ", "
}
rsp += s.String()
}
return rsp
}
func (p *recvdPackets) needToAck() bool {
return p.unacked
}
// Prepare a list of the ACK ranges, starting at the highest
func (p *recvdPackets) prepareAckRange(epoch mint.Epoch, allowAckOnly bool) ackRanges {
p.log(logTypeAck, "Prepare ACK range epoch=%d", epoch)
// Don't ACK if there's nothing new to ACK
if !p.unacked {
p.log(logTypeAck, "Nothing new to ACK")
return nil
}
var last uint64
var pn uint64
inrange := false
nonAcks := false
ranges := make(ackRanges, 0)
newMinNotAcked2 := p.maxReceived
// TODO(ekr@rtfm.com): This is kind of a gross hack in case
// someone sends us a 0 initial packet number.
for pn = p.maxReceived; pn >= p.minNotAcked2 && pn > 0; pn-- {
p.log(logTypeTrace, "Examining packet %x", pn)
pk, ok := p.packets[pn]
needs_ack := false
// If we don't know about the packet, or if the ack has been
// acked, we don't need to ack it.
if ok && !pk.acked2 {
needs_ack = true
newMinNotAcked2 = pn
}
if ok && pk.acked2 {
delete(p.packets, pn)
}
if needs_ack {
p.log(logTypeTrace, "Acking packet %x", pn)
}
if needs_ack && pk.nonAcks {
// Note if this is an ack of anything other than
// acks.
p.log(logTypeTrace, "Packet %x contains non-acks", pn)
nonAcks = true
}
if inrange != needs_ack {
if inrange {
// This is the end of a range.
ranges = append(ranges, ackRange{last, last - pn})
} else {
last = pn
}
inrange = needs_ack
}
}
if inrange {
p.log(logTypeTrace, "Appending final range %x-%x", last, pn+1)
ranges = append(ranges, ackRange{last, last - pn})
}
p.minNotAcked2 = newMinNotAcked2
p.log(logTypeAck, "%v ACK ranges to send", len(ranges))
for i, r := range ranges {
p.log(logTypeAck, " %d = %v", i, r.String())
}
if !allowAckOnly && !nonAcks {
p.log(logTypeAck, "No non-ack packets and this ack is not ack-only capable")
return nil
}
p.unacked = false
return ranges
}