1 files changed, 46 insertions, 83 deletions

diff --git a/pkg/tcpip/transport/tcp/rack.go b/pkg/tcpip/transport/tcp/rack.go
index 0a0d5f7a1..9e332dcf7 100644
--- a/pkg/tcpip/transport/tcp/rack.go
+++ b/pkg/tcpip/transport/tcp/rack.go
@@ -19,6 +19,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/seqnum"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
 )
 
 const (
@@ -46,54 +47,16 @@ const (
 //
 // +stateify savable
 type rackControl struct {
-	// dsackSeen indicates if the connection has seen a DSACK.
-	dsackSeen bool
-
-	// endSequence is the ending TCP sequence number of the most recent
-	// acknowledged segment.
-	endSequence seqnum.Value
+	stack.TCPRACKState
 
 	// exitedRecovery indicates if the connection is exiting loss recovery.
 	// This flag is set if the sender is leaving the recovery after
 	// receiving an ACK and is reset during updating of reorder window.
 	exitedRecovery bool
 
-	// fack is the highest selectively or cumulatively acknowledged
-	// sequence.
-	fack seqnum.Value
-
 	// minRTT is the estimated minimum RTT of the connection.
 	minRTT time.Duration
 
-	// reorderSeen indicates if reordering has been detected on this
-	// connection.
-	reorderSeen bool
-
-	// reoWnd is the reordering window time used for recording packet
-	// transmission times. It is used to defer the moment at which RACK
-	// marks a packet lost.
-	reoWnd time.Duration
-
-	// reoWndIncr is the multiplier applied to adjust reorder window.
-	reoWndIncr uint8
-
-	// reoWndPersist is the number of loss recoveries before resetting
-	// reorder window.
-	reoWndPersist int8
-
-	// rtt is the RTT of the most recently delivered packet on the
-	// connection (either cumulatively acknowledged or selectively
-	// acknowledged) that was not marked invalid as a possible spurious
-	// retransmission.
-	rtt time.Duration
-
-	// rttSeq is the SND.NXT when rtt is updated.
-	rttSeq seqnum.Value
-
-	// xmitTime is the latest transmission timestamp of the most recent
-	// acknowledged segment.
-	xmitTime time.Time `state:".(unixTime)"`
-
 	// tlpRxtOut indicates whether there is an unacknowledged
 	// TLP retransmission.
 	tlpRxtOut bool
@@ -108,8 +71,8 @@ type rackControl struct {
 
 // init initializes RACK specific fields.
 func (rc *rackControl) init(snd *sender, iss seqnum.Value) {
-	rc.fack = iss
-	rc.reoWndIncr = 1
+	rc.FACK = iss
+	rc.ReoWndIncr = 1
 	rc.snd = snd
 }
 
@@ -117,7 +80,7 @@ func (rc *rackControl) init(snd *sender, iss seqnum.Value) {
 // See: https://tools.ietf.org/html/draft-ietf-tcpm-rack-09#section-6.2
 func (rc *rackControl) update(seg *segment, ackSeg *segment) {
 	rtt := time.Now().Sub(seg.xmitTime)
-	tsOffset := rc.snd.ep.tsOffset
+	tsOffset := rc.snd.ep.TSOffset
 
 	// If the ACK is for a retransmitted packet, do not update if it is a
 	// spurious inference which is determined by below checks:
@@ -138,7 +101,7 @@ func (rc *rackControl) update(seg *segment, ackSeg *segment) {
 		}
 	}
 
-	rc.rtt = rtt
+	rc.RTT = rtt
 
 	// The sender can either track a simple global minimum of all RTT
 	// measurements from the connection, or a windowed min-filtered value
@@ -152,9 +115,9 @@ func (rc *rackControl) update(seg *segment, ackSeg *segment) {
 	// ending sequence number of the packet which has been acknowledged
 	// most recently.
 	endSeq := seg.sequenceNumber.Add(seqnum.Size(seg.data.Size()))
-	if rc.xmitTime.Before(seg.xmitTime) || (seg.xmitTime.Equal(rc.xmitTime) && rc.endSequence.LessThan(endSeq)) {
-		rc.xmitTime = seg.xmitTime
-		rc.endSequence = endSeq
+	if rc.XmitTime.Before(seg.xmitTime) || (seg.xmitTime.Equal(rc.XmitTime) && rc.EndSequence.LessThan(endSeq)) {
+		rc.XmitTime = seg.xmitTime
+		rc.EndSequence = endSeq
 	}
 }
 
@@ -171,18 +134,18 @@ func (rc *rackControl) update(seg *segment, ackSeg *segment) {
 //   is identified.
 func (rc *rackControl) detectReorder(seg *segment) {
 	endSeq := seg.sequenceNumber.Add(seqnum.Size(seg.data.Size()))
-	if rc.fack.LessThan(endSeq) {
-		rc.fack = endSeq
+	if rc.FACK.LessThan(endSeq) {
+		rc.FACK = endSeq
 		return
 	}
 
-	if endSeq.LessThan(rc.fack) && seg.xmitCount == 1 {
-		rc.reorderSeen = true
+	if endSeq.LessThan(rc.FACK) && seg.xmitCount == 1 {
+		rc.Reord = true
 	}
 }
 
 func (rc *rackControl) setDSACKSeen(dsackSeen bool) {
-	rc.dsackSeen = dsackSeen
+	rc.DSACKSeen = dsackSeen
 }
 
 // shouldSchedulePTO dictates whether we should schedule a PTO or not.
@@ -191,7 +154,7 @@ func (s *sender) shouldSchedulePTO() bool {
 	// Schedule PTO only if RACK loss detection is enabled.
 	return s.ep.tcpRecovery&tcpip.TCPRACKLossDetection != 0 &&
 		// The connection supports SACK.
-		s.ep.sackPermitted &&
+		s.ep.SACKPermitted &&
 		// The connection is not in loss recovery.
 		(s.state != tcpip.RTORecovery && s.state != tcpip.SACKRecovery) &&
 		// The connection has no SACKed sequences in the SACK scoreboard.
@@ -203,9 +166,9 @@ func (s *sender) shouldSchedulePTO() bool {
 func (s *sender) schedulePTO() {
 	pto := time.Second
 	s.rtt.Lock()
-	if s.rtt.srttInited && s.rtt.srtt > 0 {
-		pto = s.rtt.srtt * 2
-		if s.outstanding == 1 {
+	if s.rtt.TCPRTTState.SRTTInited && s.rtt.TCPRTTState.SRTT > 0 {
+		pto = s.rtt.TCPRTTState.SRTT * 2
+		if s.Outstanding == 1 {
 			pto += wcDelayedACKTimeout
 		}
 	}
@@ -230,10 +193,10 @@ func (s *sender) probeTimerExpired() tcpip.Error {
 	}
 
 	var dataSent bool
-	if s.writeNext != nil && s.writeNext.xmitCount == 0 && s.outstanding < s.sndCwnd {
-		dataSent = s.maybeSendSegment(s.writeNext, int(s.ep.scoreboard.SMSS()), s.sndUna.Add(s.sndWnd))
+	if s.writeNext != nil && s.writeNext.xmitCount == 0 && s.Outstanding < s.SndCwnd {
+		dataSent = s.maybeSendSegment(s.writeNext, int(s.ep.scoreboard.SMSS()), s.SndUna.Add(s.SndWnd))
 		if dataSent {
-			s.outstanding += s.pCount(s.writeNext, s.maxPayloadSize)
+			s.Outstanding += s.pCount(s.writeNext, s.MaxPayloadSize)
 			s.writeNext = s.writeNext.Next()
 		}
 	}
@@ -255,10 +218,10 @@ func (s *sender) probeTimerExpired() tcpip.Error {
 		}
 
 		if highestSeqXmit != nil {
-			dataSent = s.maybeSendSegment(highestSeqXmit, int(s.ep.scoreboard.SMSS()), s.sndUna.Add(s.sndWnd))
+			dataSent = s.maybeSendSegment(highestSeqXmit, int(s.ep.scoreboard.SMSS()), s.SndUna.Add(s.SndWnd))
 			if dataSent {
 				s.rc.tlpRxtOut = true
-				s.rc.tlpHighRxt = s.sndNxt
+				s.rc.tlpHighRxt = s.SndNxt
 			}
 		}
 	}
@@ -274,7 +237,7 @@ func (s *sender) probeTimerExpired() tcpip.Error {
 // and updates TLP state accordingly.
 // See https://tools.ietf.org/html/draft-ietf-tcpm-rack-08#section-7.6.3.
 func (s *sender) detectTLPRecovery(ack seqnum.Value, rcvdSeg *segment) {
-	if !(s.ep.sackPermitted && s.rc.tlpRxtOut) {
+	if !(s.ep.SACKPermitted && s.rc.tlpRxtOut) {
 		return
 	}
 
@@ -317,13 +280,13 @@ func (s *sender) detectTLPRecovery(ack seqnum.Value, rcvdSeg *segment) {
 //   retransmit quickly, or when the number of DUPACKs exceeds the classic
 //   DUPACKthreshold.
 func (rc *rackControl) updateRACKReorderWindow(ackSeg *segment) {
-	dsackSeen := rc.dsackSeen
+	dsackSeen := rc.DSACKSeen
 	snd := rc.snd
 
 	// React to DSACK once per round trip.
 	// If SND.UNA < RACK.rtt_seq:
 	//   RACK.dsack = false
-	if snd.sndUna.LessThan(rc.rttSeq) {
+	if snd.SndUna.LessThan(rc.RTTSeq) {
 		dsackSeen = false
 	}
 
@@ -333,18 +296,18 @@ func (rc *rackControl) updateRACKReorderWindow(ackSeg *segment) {
 	//   RACK.rtt_seq = SND.NXT
 	//   RACK.reo_wnd_persist = 16
 	if dsackSeen {
-		rc.reoWndIncr++
+		rc.ReoWndIncr++
 		dsackSeen = false
-		rc.rttSeq = snd.sndNxt
-		rc.reoWndPersist = tcpRACKRecoveryThreshold
+		rc.RTTSeq = snd.SndNxt
+		rc.ReoWndPersist = tcpRACKRecoveryThreshold
 	} else if rc.exitedRecovery {
 		// Else if exiting loss recovery:
 		//   RACK.reo_wnd_persist -= 1
 		//   If RACK.reo_wnd_persist <= 0:
 		//      RACK.reo_wnd_incr = 1
-		rc.reoWndPersist--
-		if rc.reoWndPersist <= 0 {
-			rc.reoWndIncr = 1
+		rc.ReoWndPersist--
+		if rc.ReoWndPersist <= 0 {
+			rc.ReoWndIncr = 1
 		}
 		rc.exitedRecovery = false
 	}
@@ -358,14 +321,14 @@ func (rc *rackControl) updateRACKReorderWindow(ackSeg *segment) {
 	//   Else if RACK.pkts_sacked >= RACK.dupthresh:
 	//     RACK.reo_wnd = 0
 	//     return
-	if !rc.reorderSeen {
+	if !rc.Reord {
 		if snd.state == tcpip.RTORecovery || snd.state == tcpip.SACKRecovery {
-			rc.reoWnd = 0
+			rc.ReoWnd = 0
 			return
 		}
 
-		if snd.sackedOut >= nDupAckThreshold {
-			rc.reoWnd = 0
+		if snd.SackedOut >= nDupAckThreshold {
+			rc.ReoWnd = 0
 			return
 		}
 	}
@@ -374,11 +337,11 @@ func (rc *rackControl) updateRACKReorderWindow(ackSeg *segment) {
 	// RACK.reo_wnd = RACK.min_RTT / 4 * RACK.reo_wnd_incr
 	// RACK.reo_wnd = min(RACK.reo_wnd, SRTT)
 	snd.rtt.Lock()
-	srtt := snd.rtt.srtt
+	srtt := snd.rtt.TCPRTTState.SRTT
 	snd.rtt.Unlock()
-	rc.reoWnd = time.Duration((int64(rc.minRTT) / 4) * int64(rc.reoWndIncr))
-	if srtt < rc.reoWnd {
-		rc.reoWnd = srtt
+	rc.ReoWnd = time.Duration((int64(rc.minRTT) / 4) * int64(rc.ReoWndIncr))
+	if srtt < rc.ReoWnd {
+		rc.ReoWnd = srtt
 	}
 }
 
@@ -403,8 +366,8 @@ func (rc *rackControl) detectLoss(rcvTime time.Time) int {
 		}
 
 		endSeq := seg.sequenceNumber.Add(seqnum.Size(seg.data.Size()))
-		if seg.xmitTime.Before(rc.xmitTime) || (seg.xmitTime.Equal(rc.xmitTime) && rc.endSequence.LessThan(endSeq)) {
-			timeRemaining := seg.xmitTime.Sub(rcvTime) + rc.rtt + rc.reoWnd
+		if seg.xmitTime.Before(rc.XmitTime) || (seg.xmitTime.Equal(rc.XmitTime) && rc.EndSequence.LessThan(endSeq)) {
+			timeRemaining := seg.xmitTime.Sub(rcvTime) + rc.RTT + rc.ReoWnd
 			if timeRemaining <= 0 {
 				seg.lost = true
 				numLost++
@@ -435,7 +398,7 @@ func (rc *rackControl) reorderTimerExpired() tcpip.Error {
 	}
 
 	fastRetransmit := false
-	if !rc.snd.fr.active {
+	if !rc.snd.FastRecovery.Active {
 		rc.snd.cc.HandleLossDetected()
 		rc.snd.enterRecovery()
 		fastRetransmit = true
@@ -471,15 +434,15 @@ func (rc *rackControl) DoRecovery(_ *segment, fastRetransmit bool) {
 		}
 
 		// Check the congestion window after entering recovery.
-		if snd.outstanding >= snd.sndCwnd {
+		if snd.Outstanding >= snd.SndCwnd {
 			break
 		}
 
-		if sent := snd.maybeSendSegment(seg, int(snd.ep.scoreboard.SMSS()), snd.sndUna.Add(snd.sndWnd)); !sent {
+		if sent := snd.maybeSendSegment(seg, int(snd.ep.scoreboard.SMSS()), snd.SndUna.Add(snd.SndWnd)); !sent {
 			break
 		}
 		dataSent = true
-		snd.outstanding += snd.pCount(seg, snd.maxPayloadSize)
+		snd.Outstanding += snd.pCount(seg, snd.MaxPayloadSize)
 	}
 
 	snd.postXmit(dataSent, true /* shouldScheduleProbe */)