Automated rollback of changelist 261191548

PiperOrigin-RevId: 261373749

6 files changed, 45 insertions, 85 deletions

diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 7c31cf493..6156c3f46 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -208,10 +208,6 @@ type TCPSenderState struct {
 
 	// Cubic holds the state related to CUBIC congestion control.
 	Cubic TCPCubicState
-
-	// MSS is the size of the largest segment that can be sent without
-	// fragmentation.
-	MSS int
 }
 
 // TCPSACKInfo holds TCP SACK related information for a given TCP endpoint.
@@ -224,9 +220,6 @@ type TCPSACKInfo struct {
 	// from the peer endpoint.
 	ReceivedBlocks []header.SACKBlock
 
-	// Sacked is the current number of bytes held in the SACK scoreboard.
-	Sacked seqnum.Size
-
 	// MaxSACKED is the highest sequence number that has been SACKED
 	// by the peer.
 	MaxSACKED seqnum.Value
@@ -276,14 +269,6 @@ type TCPEndpointState struct {
 	// ID is a copy of the TransportEndpointID for the endpoint.
 	ID TCPEndpointID
 
-	// ProtocolState denotes the TCP state the endpoint is currently
-	// in, encoded in a netstack-specific manner. Should be translated
-	// to the Linux ABI before exposing to userspace.
-	ProtocolState uint32
-
-	// AMSS is the MSS advertised to the peer by this endpoint.
-	AMSS uint16
-
 	// SegTime denotes the absolute time when this segment was received.
 	SegTime time.Time
 
@@ -301,18 +286,6 @@ type TCPEndpointState struct {
 	// RcvClosed if true, indicates the endpoint has been closed for reading.
 	RcvClosed bool
 
-	// RcvLastAck is the time of receipt of the last packet with the
-	// ACK flag set.
-	RcvLastAckNanos int64
-
-	// RcvLastData is the time of reciept of the last packet
-	// containing data.
-	RcvLastDataNanos int64
-
-	// RcvMSS is the size of the largest segment the receiver is willing to
-	// accept, not including TCP headers and options.
-	RcvMSS int
-
 	// SendTSOk is used to indicate when the TS Option has been negotiated.
 	// When sendTSOk is true every non-RST segment should carry a TS as per
 	// RFC7323#section-1.1.
@@ -353,9 +326,6 @@ type TCPEndpointState struct {
 	// SndMTU is the smallest MTU seen in the control packets received.
 	SndMTU int
 
-	// MaxOptionSize is the maximum size of TCP options.
-	MaxOptionSize int
-
 	// Receiver holds variables related to the TCP receiver for the endpoint.
 	Receiver TCPReceiverState
 
diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go
index 690c00edb..4208c0303 100644
--- a/pkg/tcpip/tcpip.go
+++ b/pkg/tcpip/tcpip.go
@@ -476,6 +476,14 @@ type QuickAckOption int
 // Only supported on Unix sockets.
 type PasscredOption int
 
+// TCPInfoOption is used by GetSockOpt to expose TCP statistics.
+//
+// TODO(b/64800844): Add and populate stat fields.
+type TCPInfoOption struct {
+	RTT    time.Duration
+	RTTVar time.Duration
+}
+
 // KeepaliveEnabledOption is used by SetSockOpt/GetSockOpt to specify whether
 // TCP keepalive is enabled for this socket.
 type KeepaliveEnabledOption int
diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index e94307bd5..cc49c8272 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -108,9 +108,6 @@ func (s EndpointState) String() string {
 	}
 }
 
-// InfoOption is used by GetSockOpt to expose TCP endpoint state.
-type InfoOption stack.TCPEndpointState
-
 // Reasons for notifying the protocol goroutine.
 const (
 	notifyNonZeroReceiveWindow = 1 << iota
@@ -205,14 +202,12 @@ type endpoint struct {
 	// to indicate to users that no more data is coming.
 	//
 	// rcvListMu can be taken after the endpoint mu below.
-	rcvListMu        sync.Mutex  `state:"nosave"`
-	rcvList          segmentList `state:"wait"`
-	rcvClosed        bool
-	rcvBufSize       int
-	rcvBufUsed       int
-	rcvAutoParams    rcvBufAutoTuneParams
-	rcvLastAckNanos  int64 // timestamp
-	rcvLastDataNanos int64 // timestamp
+	rcvListMu     sync.Mutex  `state:"nosave"`
+	rcvList       segmentList `state:"wait"`
+	rcvClosed     bool
+	rcvBufSize    int
+	rcvBufUsed    int
+	rcvAutoParams rcvBufAutoTuneParams
 	// zeroWindow indicates that the window was closed due to receive buffer
 	// space being filled up. This is set by the worker goroutine before
 	// moving a segment to the rcvList. This setting is cleared by the
@@ -1203,10 +1198,17 @@ func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 		}
 		return nil
 
-	case *InfoOption:
-		e.workMu.Lock()
-		*o = InfoOption(e.completeState())
-		e.workMu.Unlock()
+	case *tcpip.TCPInfoOption:
+		*o = tcpip.TCPInfoOption{}
+		e.mu.RLock()
+		snd := e.snd
+		e.mu.RUnlock()
+		if snd != nil {
+			snd.rtt.Lock()
+			o.RTT = snd.rtt.srtt
+			o.RTTVar = snd.rtt.rttvar
+			snd.rtt.Unlock()
+		}
 		return nil
 
 	case *tcpip.KeepaliveEnabledOption:
@@ -1931,27 +1933,22 @@ func (e *endpoint) maxOptionSize() (size int) {
 }
 
 // completeState makes a full copy of the endpoint and returns it. This is used
-// before invoking the probe and for getsockopt(TCP_INFO). The state returned
-// may not be fully consistent if there are intervening syscalls when the state
-// is being copied.
+// before invoking the probe. The state returned may not be fully consistent if
+// there are intervening syscalls when the state is being copied.
 func (e *endpoint) completeState() stack.TCPEndpointState {
 	var s stack.TCPEndpointState
 	s.SegTime = time.Now()
 
-	e.mu.RLock()
+	// Copy EndpointID.
+	e.mu.Lock()
 	s.ID = stack.TCPEndpointID(e.id)
-	s.ProtocolState = uint32(e.state)
-	s.AMSS = e.amss
-	s.RcvMSS = int(e.amss) - e.maxOptionSize()
-	e.mu.RUnlock()
+	e.mu.Unlock()
 
 	// Copy endpoint rcv state.
 	e.rcvListMu.Lock()
 	s.RcvBufSize = e.rcvBufSize
 	s.RcvBufUsed = e.rcvBufUsed
 	s.RcvClosed = e.rcvClosed
-	s.RcvLastAckNanos = e.rcvLastAckNanos
-	s.RcvLastDataNanos = e.rcvLastDataNanos
 	s.RcvAutoParams.MeasureTime = e.rcvAutoParams.measureTime
 	s.RcvAutoParams.CopiedBytes = e.rcvAutoParams.copied
 	s.RcvAutoParams.PrevCopiedBytes = e.rcvAutoParams.prevCopied
@@ -1959,7 +1956,6 @@ func (e *endpoint) completeState() stack.TCPEndpointState {
 	s.RcvAutoParams.RTTMeasureSeqNumber = e.rcvAutoParams.rttMeasureSeqNumber
 	s.RcvAutoParams.RTTMeasureTime = e.rcvAutoParams.rttMeasureTime
 	s.RcvAutoParams.Disabled = e.rcvAutoParams.disabled
-
 	e.rcvListMu.Unlock()
 
 	// Endpoint TCP Option state.
@@ -1969,7 +1965,7 @@ func (e *endpoint) completeState() stack.TCPEndpointState {
 	s.SACKPermitted = e.sackPermitted
 	s.SACK.Blocks = make([]header.SACKBlock, e.sack.NumBlocks)
 	copy(s.SACK.Blocks, e.sack.Blocks[:e.sack.NumBlocks])
-	s.SACK.ReceivedBlocks, s.SACK.Sacked, s.SACK.MaxSACKED = e.scoreboard.Copy()
+	s.SACK.ReceivedBlocks, s.SACK.MaxSACKED = e.scoreboard.Copy()
 
 	// Copy endpoint send state.
 	e.sndBufMu.Lock()
@@ -2013,14 +2009,12 @@ func (e *endpoint) completeState() stack.TCPEndpointState {
 		RTTMeasureTime:   e.snd.rttMeasureTime,
 		Closed:           e.snd.closed,
 		RTO:              e.snd.rto,
-		MSS:              e.snd.mss,
 		MaxPayloadSize:   e.snd.maxPayloadSize,
 		SndWndScale:      e.snd.sndWndScale,
 		MaxSentAck:       e.snd.maxSentAck,
 	}
 	e.snd.rtt.Lock()
 	s.Sender.SRTT = e.snd.rtt.srtt
-	s.Sender.RTTVar = e.snd.rtt.rttvar
 	s.Sender.SRTTInited = e.snd.rtt.srttInited
 	e.snd.rtt.Unlock()
 
@@ -2065,8 +2059,8 @@ func (e *endpoint) initGSO() {
 // State implements tcpip.Endpoint.State. It exports the endpoint's protocol
 // state for diagnostics.
 func (e *endpoint) State() uint32 {
-	e.mu.RLock()
-	defer e.mu.RUnlock()
+	e.mu.Lock()
+	defer e.mu.Unlock()
 	return uint32(e.state)
 }
 
diff --git a/pkg/tcpip/transport/tcp/rcv.go b/pkg/tcpip/transport/tcp/rcv.go
index a8f490c4a..e90f9a7d9 100644
--- a/pkg/tcpip/transport/tcp/rcv.go
+++ b/pkg/tcpip/transport/tcp/rcv.go
@@ -220,24 +220,25 @@ func (r *receiver) consumeSegment(s *segment, segSeq seqnum.Value, segLen seqnum
 	return true
 }
 
-// updateRTTLocked updates the receiver RTT measurement based on the sequence
-// number of the received segment.
-//
-// Precondition: Caller must hold r.ep.rcvListMu.
-func (r *receiver) updateRTTLocked() {
+// updateRTT updates the receiver RTT measurement based on the sequence number
+// of the received segment.
+func (r *receiver) updateRTT() {
 	// From: https://public.lanl.gov/radiant/pubs/drs/sc2001-poster.pdf
 	//
 	// A system that is only transmitting acknowledgements can still
 	// estimate the round-trip time by observing the time between when a byte
 	// is first acknowledged and the receipt of data that is at least one
 	// window beyond the sequence number that was acknowledged.
+	r.ep.rcvListMu.Lock()
 	if r.ep.rcvAutoParams.rttMeasureTime.IsZero() {
 		// New measurement.
 		r.ep.rcvAutoParams.rttMeasureTime = time.Now()
 		r.ep.rcvAutoParams.rttMeasureSeqNumber = r.rcvNxt.Add(r.rcvWnd)
+		r.ep.rcvListMu.Unlock()
 		return
 	}
 	if r.rcvNxt.LessThan(r.ep.rcvAutoParams.rttMeasureSeqNumber) {
+		r.ep.rcvListMu.Unlock()
 		return
 	}
 	rtt := time.Since(r.ep.rcvAutoParams.rttMeasureTime)
@@ -249,6 +250,7 @@ func (r *receiver) updateRTTLocked() {
 	}
 	r.ep.rcvAutoParams.rttMeasureTime = time.Now()
 	r.ep.rcvAutoParams.rttMeasureSeqNumber = r.rcvNxt.Add(r.rcvWnd)
+	r.ep.rcvListMu.Unlock()
 }
 
 // handleRcvdSegment handles TCP segments directed at the connection managed by
@@ -289,20 +291,11 @@ func (r *receiver) handleRcvdSegment(s *segment) {
 		return
 	}
 
-	r.ep.rcvListMu.Lock()
-	// FIXME(b/137581805): Using the runtime clock here is incorrect as it
-	// doesn't account for potentially virtualized time.
-	now := time.Now().UnixNano()
-	if s.flagIsSet(header.TCPFlagAck) {
-		r.ep.rcvLastAckNanos = now
-	}
+	// Since we consumed a segment update the receiver's RTT estimate
+	// if required.
 	if segLen > 0 {
-		// Since we consumed a segment update the receiver's RTT estimate if
-		// required.
-		r.ep.rcvLastDataNanos = now
-		r.updateRTTLocked()
+		r.updateRTT()
 	}
-	r.ep.rcvListMu.Unlock()
 
 	// By consuming the current segment, we may have filled a gap in the
 	// sequence number domain that allows pending segments to be consumed
diff --git a/pkg/tcpip/transport/tcp/sack_scoreboard.go b/pkg/tcpip/transport/tcp/sack_scoreboard.go
index 02e52a63b..7ef2df377 100644
--- a/pkg/tcpip/transport/tcp/sack_scoreboard.go
+++ b/pkg/tcpip/transport/tcp/sack_scoreboard.go
@@ -208,12 +208,12 @@ func (s *SACKScoreboard) Delete(seq seqnum.Value) {
 }
 
 // Copy provides a copy of the SACK scoreboard.
-func (s *SACKScoreboard) Copy() (sackBlocks []header.SACKBlock, sacked seqnum.Size, maxSACKED seqnum.Value) {
+func (s *SACKScoreboard) Copy() (sackBlocks []header.SACKBlock, maxSACKED seqnum.Value) {
 	s.ranges.Ascend(func(i btree.Item) bool {
 		sackBlocks = append(sackBlocks, i.(header.SACKBlock))
 		return true
 	})
-	return sackBlocks, s.sacked, s.maxSACKED
+	return sackBlocks, s.maxSACKED
 }
 
 // IsRangeLost implements the IsLost(SeqNum) operation defined in RFC 6675
diff --git a/pkg/tcpip/transport/tcp/snd.go b/pkg/tcpip/transport/tcp/snd.go
index daf28a49a..0fee7ab72 100644
--- a/pkg/tcpip/transport/tcp/snd.go
+++ b/pkg/tcpip/transport/tcp/snd.go
@@ -124,10 +124,6 @@ type sender struct {
 	rtt rtt
 	rto time.Duration
 
-	// mss is the largest segment that can be sent without fragmentation.
-	// Initialized when then sender is created, read-only afterwards.
-	mss int
-
 	// maxPayloadSize is the maximum size of the payload of a given segment.
 	// It is initialized on demand.
 	maxPayloadSize int
@@ -205,7 +201,6 @@ func newSender(ep *endpoint, iss, irs seqnum.Value, sndWnd seqnum.Size, mss uint
 		rto:              1 * time.Second,
 		rttMeasureSeqNum: iss + 1,
 		lastSendTime:     time.Now(),
-		mss:              int(mss),
 		maxPayloadSize:   maxPayloadSize,
 		maxSentAck:       irs + 1,
 		fr: fastRecovery{