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-rw-r--r--pkg/tcpip/transport/tcp/accept.go14
-rw-r--r--pkg/tcpip/transport/tcp/connect.go48
-rw-r--r--pkg/tcpip/transport/tcp/endpoint.go178
-rw-r--r--pkg/tcpip/transport/tcp/endpoint_state.go20
-rw-r--r--pkg/tcpip/transport/tcp/forwarder.go2
-rw-r--r--pkg/tcpip/transport/tcp/protocol.go36
-rw-r--r--pkg/tcpip/transport/tcp/rcv.go78
-rw-r--r--pkg/tcpip/transport/tcp/sack.go12
-rw-r--r--pkg/tcpip/transport/tcp/snd.go14
-rwxr-xr-xpkg/tcpip/transport/tcp/tcp_state_autogen.go36
10 files changed, 387 insertions, 51 deletions
diff --git a/pkg/tcpip/transport/tcp/accept.go b/pkg/tcpip/transport/tcp/accept.go
index 9b1ad6a28..52fd1bfa3 100644
--- a/pkg/tcpip/transport/tcp/accept.go
+++ b/pkg/tcpip/transport/tcp/accept.go
@@ -213,6 +213,7 @@ func (l *listenContext) createConnectingEndpoint(s *segment, iss seqnum.Value, i
n.route = s.route.Clone()
n.effectiveNetProtos = []tcpip.NetworkProtocolNumber{s.route.NetProto}
n.rcvBufSize = int(l.rcvWnd)
+ n.amss = mssForRoute(&n.route)
n.maybeEnableTimestamp(rcvdSynOpts)
n.maybeEnableSACKPermitted(rcvdSynOpts)
@@ -232,7 +233,11 @@ func (l *listenContext) createConnectingEndpoint(s *segment, iss seqnum.Value, i
// The receiver at least temporarily has a zero receive window scale,
// but the caller may change it (before starting the protocol loop).
n.snd = newSender(n, iss, irs, s.window, rcvdSynOpts.MSS, rcvdSynOpts.WS)
- n.rcv = newReceiver(n, irs, l.rcvWnd, 0)
+ n.rcv = newReceiver(n, irs, seqnum.Size(n.initialReceiveWindow()), 0, seqnum.Size(n.receiveBufferSize()))
+ // Bootstrap the auto tuning algorithm. Starting at zero will result in
+ // a large step function on the first window adjustment causing the
+ // window to grow to a really large value.
+ n.rcvAutoParams.prevCopied = n.initialReceiveWindow()
return n, nil
}
@@ -249,7 +254,7 @@ func (l *listenContext) createEndpointAndPerformHandshake(s *segment, opts *head
}
// Perform the 3-way handshake.
- h := newHandshake(ep, l.rcvWnd)
+ h := newHandshake(ep, seqnum.Size(ep.initialReceiveWindow()))
h.resetToSynRcvd(cookie, irs, opts)
if err := h.execute(); err != nil {
@@ -359,16 +364,19 @@ func (e *endpoint) handleListenSegment(ctx *listenContext, s *segment) {
return
}
cookie := ctx.createCookie(s.id, s.sequenceNumber, encodeMSS(opts.MSS))
- // Send SYN with window scaling because we currently
+
+ // Send SYN without window scaling because we currently
// dont't encode this information in the cookie.
//
// Enable Timestamp option if the original syn did have
// the timestamp option specified.
+ mss := mssForRoute(&s.route)
synOpts := header.TCPSynOptions{
WS: -1,
TS: opts.TS,
TSVal: tcpTimeStamp(timeStampOffset()),
TSEcr: opts.TSVal,
+ MSS: uint16(mss),
}
sendSynTCP(&s.route, s.id, header.TCPFlagSyn|header.TCPFlagAck, cookie, s.sequenceNumber+1, ctx.rcvWnd, synOpts)
e.stack.Stats().TCP.ListenOverflowSynCookieSent.Increment()
diff --git a/pkg/tcpip/transport/tcp/connect.go b/pkg/tcpip/transport/tcp/connect.go
index 84e3dd26c..00d2ae524 100644
--- a/pkg/tcpip/transport/tcp/connect.go
+++ b/pkg/tcpip/transport/tcp/connect.go
@@ -78,6 +78,9 @@ type handshake struct {
// mss is the maximum segment size received from the peer.
mss uint16
+ // amss is the maximum segment size advertised by us to the peer.
+ amss uint16
+
// sndWndScale is the send window scale, as defined in RFC 1323. A
// negative value means no scaling is supported by the peer.
sndWndScale int
@@ -87,11 +90,24 @@ type handshake struct {
}
func newHandshake(ep *endpoint, rcvWnd seqnum.Size) handshake {
+ rcvWndScale := ep.rcvWndScaleForHandshake()
+
+ // Round-down the rcvWnd to a multiple of wndScale. This ensures that the
+ // window offered in SYN won't be reduced due to the loss of precision if
+ // window scaling is enabled after the handshake.
+ rcvWnd = (rcvWnd >> uint8(rcvWndScale)) << uint8(rcvWndScale)
+
+ // Ensure we can always accept at least 1 byte if the scale specified
+ // was too high for the provided rcvWnd.
+ if rcvWnd == 0 {
+ rcvWnd = 1
+ }
+
h := handshake{
ep: ep,
active: true,
rcvWnd: rcvWnd,
- rcvWndScale: FindWndScale(rcvWnd),
+ rcvWndScale: int(rcvWndScale),
}
h.resetState()
return h
@@ -224,7 +240,7 @@ func (h *handshake) synSentState(s *segment) *tcpip.Error {
h.ep.state = StateSynRecv
h.ep.mu.Unlock()
synOpts := header.TCPSynOptions{
- WS: h.rcvWndScale,
+ WS: int(h.effectiveRcvWndScale()),
TS: rcvSynOpts.TS,
TSVal: h.ep.timestamp(),
TSEcr: h.ep.recentTS,
@@ -233,6 +249,7 @@ func (h *handshake) synSentState(s *segment) *tcpip.Error {
// permits SACK. This is not explicitly defined in the RFC but
// this is the behaviour implemented by Linux.
SACKPermitted: rcvSynOpts.SACKPermitted,
+ MSS: h.ep.amss,
}
sendSynTCP(&s.route, h.ep.id, h.flags, h.iss, h.ackNum, h.rcvWnd, synOpts)
@@ -277,6 +294,7 @@ func (h *handshake) synRcvdState(s *segment) *tcpip.Error {
TSVal: h.ep.timestamp(),
TSEcr: h.ep.recentTS,
SACKPermitted: h.ep.sackPermitted,
+ MSS: h.ep.amss,
}
sendSynTCP(&s.route, h.ep.id, h.flags, h.iss, h.ackNum, h.rcvWnd, synOpts)
return nil
@@ -419,12 +437,15 @@ func (h *handshake) execute() *tcpip.Error {
// Send the initial SYN segment and loop until the handshake is
// completed.
+ h.ep.amss = mssForRoute(&h.ep.route)
+
synOpts := header.TCPSynOptions{
WS: h.rcvWndScale,
TS: true,
TSVal: h.ep.timestamp(),
TSEcr: h.ep.recentTS,
SACKPermitted: bool(sackEnabled),
+ MSS: h.ep.amss,
}
// Execute is also called in a listen context so we want to make sure we
@@ -433,6 +454,11 @@ func (h *handshake) execute() *tcpip.Error {
if h.state == handshakeSynRcvd {
synOpts.TS = h.ep.sendTSOk
synOpts.SACKPermitted = h.ep.sackPermitted && bool(sackEnabled)
+ if h.sndWndScale < 0 {
+ // Disable window scaling if the peer did not send us
+ // the window scaling option.
+ synOpts.WS = -1
+ }
}
sendSynTCP(&h.ep.route, h.ep.id, h.flags, h.iss, h.ackNum, h.rcvWnd, synOpts)
for h.state != handshakeCompleted {
@@ -554,13 +580,6 @@ func makeSynOptions(opts header.TCPSynOptions) []byte {
}
func sendSynTCP(r *stack.Route, id stack.TransportEndpointID, flags byte, seq, ack seqnum.Value, rcvWnd seqnum.Size, opts header.TCPSynOptions) *tcpip.Error {
- // The MSS in opts is automatically calculated as this function is
- // called from many places and we don't want every call point being
- // embedded with the MSS calculation.
- if opts.MSS == 0 {
- opts.MSS = uint16(r.MTU() - header.TCPMinimumSize)
- }
-
options := makeSynOptions(opts)
err := sendTCP(r, id, buffer.VectorisedView{}, r.DefaultTTL(), flags, seq, ack, rcvWnd, options, nil)
putOptions(options)
@@ -861,7 +880,8 @@ func (e *endpoint) protocolMainLoop(handshake bool) *tcpip.Error {
// This is an active connection, so we must initiate the 3-way
// handshake, and then inform potential waiters about its
// completion.
- h := newHandshake(e, seqnum.Size(e.receiveBufferAvailable()))
+ initialRcvWnd := e.initialReceiveWindow()
+ h := newHandshake(e, seqnum.Size(initialRcvWnd))
e.mu.Lock()
h.ep.state = StateSynSent
e.mu.Unlock()
@@ -886,8 +906,14 @@ func (e *endpoint) protocolMainLoop(handshake bool) *tcpip.Error {
// (indicated by a negative send window scale).
e.snd = newSender(e, h.iss, h.ackNum-1, h.sndWnd, h.mss, h.sndWndScale)
+ rcvBufSize := seqnum.Size(e.receiveBufferSize())
e.rcvListMu.Lock()
- e.rcv = newReceiver(e, h.ackNum-1, h.rcvWnd, h.effectiveRcvWndScale())
+ e.rcv = newReceiver(e, h.ackNum-1, h.rcvWnd, h.effectiveRcvWndScale(), rcvBufSize)
+ // boot strap the auto tuning algorithm. Starting at zero will
+ // result in a large step function on the first proper causing
+ // the window to just go to a really large value after the first
+ // RTT itself.
+ e.rcvAutoParams.prevCopied = initialRcvWnd
e.rcvListMu.Unlock()
}
diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index 9614b2958..1aa1f12b4 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -132,6 +132,42 @@ type SACKInfo struct {
NumBlocks int
}
+// rcvBufAutoTuneParams are used to hold state variables to compute
+// the auto tuned recv buffer size.
+//
+// +stateify savable
+type rcvBufAutoTuneParams struct {
+ // measureTime is the time at which the current measurement
+ // was started.
+ measureTime time.Time `state:".(unixTime)"`
+
+ // copied is the number of bytes copied out of the receive
+ // buffers since this measure began.
+ copied int
+
+ // prevCopied is the number of bytes copied out of the receive
+ // buffers in the previous RTT period.
+ prevCopied int
+
+ // rtt is the non-smoothed minimum RTT as measured 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.
+ rtt time.Duration
+
+ // rttMeasureSeqNumber is the highest acceptable sequence number at the
+ // time this RTT measurement period began.
+ rttMeasureSeqNumber seqnum.Value
+
+ // rttMeasureTime is the absolute time at which the current rtt
+ // measurement period began.
+ rttMeasureTime time.Time `state:".(unixTime)"`
+
+ // disabled is true if an explicit receive buffer is set for the
+ // endpoint.
+ disabled bool
+}
+
// endpoint represents a TCP endpoint. This struct serves as the interface
// between users of the endpoint and the protocol implementation; it is legal to
// have concurrent goroutines make calls into the endpoint, they are properly
@@ -165,11 +201,12 @@ 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
+ rcvListMu sync.Mutex `state:"nosave"`
+ rcvList segmentList `state:"wait"`
+ rcvClosed bool
+ rcvBufSize int
+ rcvBufUsed int
+ rcvAutoParams rcvBufAutoTuneParams
// The following fields are protected by the mutex.
mu sync.RWMutex `state:"nosave"`
@@ -339,6 +376,9 @@ type endpoint struct {
bindAddress tcpip.Address
connectingAddress tcpip.Address
+ // amss is the advertised MSS to the peer by this endpoint.
+ amss uint16
+
gso *stack.GSO
}
@@ -373,8 +413,8 @@ func newEndpoint(stack *stack.Stack, netProto tcpip.NetworkProtocolNumber, waite
netProto: netProto,
waiterQueue: waiterQueue,
state: StateInitial,
- rcvBufSize: DefaultBufferSize,
- sndBufSize: DefaultBufferSize,
+ rcvBufSize: DefaultReceiveBufferSize,
+ sndBufSize: DefaultSendBufferSize,
sndMTU: int(math.MaxInt32),
reuseAddr: true,
keepalive: keepalive{
@@ -400,6 +440,11 @@ func newEndpoint(stack *stack.Stack, netProto tcpip.NetworkProtocolNumber, waite
e.cc = cs
}
+ var mrb tcpip.ModerateReceiveBufferOption
+ if err := stack.TransportProtocolOption(ProtocolNumber, &mrb); err == nil {
+ e.rcvAutoParams.disabled = !bool(mrb)
+ }
+
if p := stack.GetTCPProbe(); p != nil {
e.probe = p
}
@@ -408,6 +453,7 @@ func newEndpoint(stack *stack.Stack, netProto tcpip.NetworkProtocolNumber, waite
e.workMu.Init()
e.workMu.Lock()
e.tsOffset = timeStampOffset()
+
return e
}
@@ -551,6 +597,83 @@ func (e *endpoint) cleanupLocked() {
tcpip.DeleteDanglingEndpoint(e)
}
+// initialReceiveWindow returns the initial receive window to advertise in the
+// SYN/SYN-ACK.
+func (e *endpoint) initialReceiveWindow() int {
+ rcvWnd := e.receiveBufferAvailable()
+ if rcvWnd > math.MaxUint16 {
+ rcvWnd = math.MaxUint16
+ }
+ routeWnd := InitialCwnd * int(mssForRoute(&e.route)) * 2
+ if rcvWnd > routeWnd {
+ rcvWnd = routeWnd
+ }
+ return rcvWnd
+}
+
+// ModerateRecvBuf adjusts the receive buffer and the advertised window
+// based on the number of bytes copied to user space.
+func (e *endpoint) ModerateRecvBuf(copied int) {
+ e.rcvListMu.Lock()
+ if e.rcvAutoParams.disabled {
+ e.rcvListMu.Unlock()
+ return
+ }
+ now := time.Now()
+ if rtt := e.rcvAutoParams.rtt; rtt == 0 || now.Sub(e.rcvAutoParams.measureTime) < rtt {
+ e.rcvAutoParams.copied += copied
+ e.rcvListMu.Unlock()
+ return
+ }
+ prevRTTCopied := e.rcvAutoParams.copied + copied
+ prevCopied := e.rcvAutoParams.prevCopied
+ rcvWnd := 0
+ if prevRTTCopied > prevCopied {
+ // The minimal receive window based on what was copied by the app
+ // in the immediate preceding RTT and some extra buffer for 16
+ // segments to account for variations.
+ // We multiply by 2 to account for packet losses.
+ rcvWnd = prevRTTCopied*2 + 16*int(e.amss)
+
+ // Scale for slow start based on bytes copied in this RTT vs previous.
+ grow := (rcvWnd * (prevRTTCopied - prevCopied)) / prevCopied
+
+ // Multiply growth factor by 2 again to account for sender being
+ // in slow-start where the sender grows it's congestion window
+ // by 100% per RTT.
+ rcvWnd += grow * 2
+
+ // Make sure auto tuned buffer size can always receive upto 2x
+ // the initial window of 10 segments.
+ if minRcvWnd := int(e.amss) * InitialCwnd * 2; rcvWnd < minRcvWnd {
+ rcvWnd = minRcvWnd
+ }
+
+ // Cap the auto tuned buffer size by the maximum permissible
+ // receive buffer size.
+ if max := e.maxReceiveBufferSize(); rcvWnd > max {
+ rcvWnd = max
+ }
+
+ // We do not adjust downwards as that can cause the receiver to
+ // reject valid data that might already be in flight as the
+ // acceptable window will shrink.
+ if rcvWnd > e.rcvBufSize {
+ e.rcvBufSize = rcvWnd
+ e.notifyProtocolGoroutine(notifyReceiveWindowChanged)
+ }
+
+ // We only update prevCopied when we grow the buffer because in cases
+ // where prevCopied > prevRTTCopied the existing buffer is already big
+ // enough to handle the current rate and we don't need to do any
+ // adjustments.
+ e.rcvAutoParams.prevCopied = prevRTTCopied
+ }
+ e.rcvAutoParams.measureTime = now
+ e.rcvAutoParams.copied = 0
+ e.rcvListMu.Unlock()
+}
+
// Read reads data from the endpoint.
func (e *endpoint) Read(*tcpip.FullAddress) (buffer.View, tcpip.ControlMessages, *tcpip.Error) {
e.mu.RLock()
@@ -821,6 +944,7 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
wasZero := e.zeroReceiveWindow(scale)
e.rcvBufSize = size
+ e.rcvAutoParams.disabled = true
if wasZero && !e.zeroReceiveWindow(scale) {
mask |= notifyNonZeroReceiveWindow
}
@@ -1657,6 +1781,33 @@ func (e *endpoint) receiveBufferSize() int {
return size
}
+func (e *endpoint) maxReceiveBufferSize() int {
+ var rs ReceiveBufferSizeOption
+ if err := e.stack.TransportProtocolOption(ProtocolNumber, &rs); err != nil {
+ // As a fallback return the hardcoded max buffer size.
+ return MaxBufferSize
+ }
+ return rs.Max
+}
+
+// rcvWndScaleForHandshake computes the receive window scale to offer to the
+// peer when window scaling is enabled (true by default). If auto-tuning is
+// disabled then the window scaling factor is based on the size of the
+// receiveBuffer otherwise we use the max permissible receive buffer size to
+// compute the scale.
+func (e *endpoint) rcvWndScaleForHandshake() int {
+ bufSizeForScale := e.receiveBufferSize()
+
+ e.rcvListMu.Lock()
+ autoTuningDisabled := e.rcvAutoParams.disabled
+ e.rcvListMu.Unlock()
+ if autoTuningDisabled {
+ return FindWndScale(seqnum.Size(bufSizeForScale))
+ }
+
+ return FindWndScale(seqnum.Size(e.maxReceiveBufferSize()))
+}
+
// updateRecentTimestamp updates the recent timestamp using the algorithm
// described in https://tools.ietf.org/html/rfc7323#section-4.3
func (e *endpoint) updateRecentTimestamp(tsVal uint32, maxSentAck seqnum.Value, segSeq seqnum.Value) {
@@ -1749,6 +1900,13 @@ func (e *endpoint) completeState() stack.TCPEndpointState {
s.RcvBufSize = e.rcvBufSize
s.RcvBufUsed = e.rcvBufUsed
s.RcvClosed = e.rcvClosed
+ s.RcvAutoParams.MeasureTime = e.rcvAutoParams.measureTime
+ s.RcvAutoParams.CopiedBytes = e.rcvAutoParams.copied
+ s.RcvAutoParams.PrevCopiedBytes = e.rcvAutoParams.prevCopied
+ s.RcvAutoParams.RTT = e.rcvAutoParams.rtt
+ 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.
@@ -1802,13 +1960,13 @@ func (e *endpoint) completeState() stack.TCPEndpointState {
RTTMeasureTime: e.snd.rttMeasureTime,
Closed: e.snd.closed,
RTO: e.snd.rto,
- SRTTInited: e.snd.srttInited,
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.SRTTInited = e.snd.rtt.srttInited
e.snd.rtt.Unlock()
if cubic, ok := e.snd.cc.(*cubicState); ok {
@@ -1856,3 +2014,7 @@ func (e *endpoint) State() uint32 {
defer e.mu.Unlock()
return uint32(e.state)
}
+
+func mssForRoute(r *stack.Route) uint16 {
+ return uint16(r.MTU() - header.TCPMinimumSize)
+}
diff --git a/pkg/tcpip/transport/tcp/endpoint_state.go b/pkg/tcpip/transport/tcp/endpoint_state.go
index 58be61927..ec61a3886 100644
--- a/pkg/tcpip/transport/tcp/endpoint_state.go
+++ b/pkg/tcpip/transport/tcp/endpoint_state.go
@@ -360,3 +360,23 @@ func loadError(s string) *tcpip.Error {
return e
}
+
+// saveMeasureTime is invoked by stateify.
+func (r *rcvBufAutoTuneParams) saveMeasureTime() unixTime {
+ return unixTime{r.measureTime.Unix(), r.measureTime.UnixNano()}
+}
+
+// loadMeasureTime is invoked by stateify.
+func (r *rcvBufAutoTuneParams) loadMeasureTime(unix unixTime) {
+ r.measureTime = time.Unix(unix.second, unix.nano)
+}
+
+// saveRttMeasureTime is invoked by stateify.
+func (r *rcvBufAutoTuneParams) saveRttMeasureTime() unixTime {
+ return unixTime{r.rttMeasureTime.Unix(), r.rttMeasureTime.UnixNano()}
+}
+
+// loadRttMeasureTime is invoked by stateify.
+func (r *rcvBufAutoTuneParams) loadRttMeasureTime(unix unixTime) {
+ r.rttMeasureTime = time.Unix(unix.second, unix.nano)
+}
diff --git a/pkg/tcpip/transport/tcp/forwarder.go b/pkg/tcpip/transport/tcp/forwarder.go
index 2ce94aeb9..63666f0b3 100644
--- a/pkg/tcpip/transport/tcp/forwarder.go
+++ b/pkg/tcpip/transport/tcp/forwarder.go
@@ -47,7 +47,7 @@ type Forwarder struct {
// If rcvWnd is set to zero, the default buffer size is used instead.
func NewForwarder(s *stack.Stack, rcvWnd, maxInFlight int, handler func(*ForwarderRequest)) *Forwarder {
if rcvWnd == 0 {
- rcvWnd = DefaultBufferSize
+ rcvWnd = DefaultReceiveBufferSize
}
return &Forwarder{
maxInFlight: maxInFlight,
diff --git a/pkg/tcpip/transport/tcp/protocol.go b/pkg/tcpip/transport/tcp/protocol.go
index 919e4ce24..ee04dcfcc 100644
--- a/pkg/tcpip/transport/tcp/protocol.go
+++ b/pkg/tcpip/transport/tcp/protocol.go
@@ -41,13 +41,18 @@ const (
ProtocolNumber = header.TCPProtocolNumber
// MinBufferSize is the smallest size of a receive or send buffer.
- minBufferSize = 4 << 10 // 4096 bytes.
+ MinBufferSize = 4 << 10 // 4096 bytes.
- // DefaultBufferSize is the default size of the receive and send buffers.
- DefaultBufferSize = 1 << 20 // 1MB
+ // DefaultSendBufferSize is the default size of the send buffer for
+ // an endpoint.
+ DefaultSendBufferSize = 1 << 20 // 1MB
- // MaxBufferSize is the largest size a receive and send buffer can grow to.
- maxBufferSize = 4 << 20 // 4MB
+ // DefaultReceiveBufferSize is the default size of the receive buffer
+ // for an endpoint.
+ DefaultReceiveBufferSize = 1 << 20 // 1MB
+
+ // MaxBufferSize is the largest size a receive/send buffer can grow to.
+ MaxBufferSize = 4 << 20 // 4MB
// MaxUnprocessedSegments is the maximum number of unprocessed segments
// that can be queued for a given endpoint.
@@ -86,6 +91,7 @@ type protocol struct {
recvBufferSize ReceiveBufferSizeOption
congestionControl string
availableCongestionControl []string
+ moderateReceiveBuffer bool
}
// Number returns the tcp protocol number.
@@ -192,6 +198,13 @@ func (p *protocol) SetOption(option interface{}) *tcpip.Error {
// linux returns ENOENT when an invalid congestion control
// is specified.
return tcpip.ErrNoSuchFile
+
+ case tcpip.ModerateReceiveBufferOption:
+ p.mu.Lock()
+ p.moderateReceiveBuffer = bool(v)
+ p.mu.Unlock()
+ return nil
+
default:
return tcpip.ErrUnknownProtocolOption
}
@@ -217,16 +230,25 @@ func (p *protocol) Option(option interface{}) *tcpip.Error {
*v = p.recvBufferSize
p.mu.Unlock()
return nil
+
case *tcpip.CongestionControlOption:
p.mu.Lock()
*v = tcpip.CongestionControlOption(p.congestionControl)
p.mu.Unlock()
return nil
+
case *tcpip.AvailableCongestionControlOption:
p.mu.Lock()
*v = tcpip.AvailableCongestionControlOption(strings.Join(p.availableCongestionControl, " "))
p.mu.Unlock()
return nil
+
+ case *tcpip.ModerateReceiveBufferOption:
+ p.mu.Lock()
+ *v = tcpip.ModerateReceiveBufferOption(p.moderateReceiveBuffer)
+ p.mu.Unlock()
+ return nil
+
default:
return tcpip.ErrUnknownProtocolOption
}
@@ -235,8 +257,8 @@ func (p *protocol) Option(option interface{}) *tcpip.Error {
func init() {
stack.RegisterTransportProtocolFactory(ProtocolName, func() stack.TransportProtocol {
return &protocol{
- sendBufferSize: SendBufferSizeOption{minBufferSize, DefaultBufferSize, maxBufferSize},
- recvBufferSize: ReceiveBufferSizeOption{minBufferSize, DefaultBufferSize, maxBufferSize},
+ sendBufferSize: SendBufferSizeOption{MinBufferSize, DefaultSendBufferSize, MaxBufferSize},
+ recvBufferSize: ReceiveBufferSizeOption{MinBufferSize, DefaultReceiveBufferSize, MaxBufferSize},
congestionControl: ccReno,
availableCongestionControl: []string{ccReno, ccCubic},
}
diff --git a/pkg/tcpip/transport/tcp/rcv.go b/pkg/tcpip/transport/tcp/rcv.go
index 8d9de9bf9..e90f9a7d9 100644
--- a/pkg/tcpip/transport/tcp/rcv.go
+++ b/pkg/tcpip/transport/tcp/rcv.go
@@ -16,6 +16,7 @@ package tcp
import (
"container/heap"
+ "time"
"gvisor.dev/gvisor/pkg/tcpip/header"
"gvisor.dev/gvisor/pkg/tcpip/seqnum"
@@ -38,6 +39,9 @@ type receiver struct {
// shrinking it.
rcvAcc seqnum.Value
+ // rcvWnd is the non-scaled receive window last advertised to the peer.
+ rcvWnd seqnum.Size
+
rcvWndScale uint8
closed bool
@@ -47,13 +51,14 @@ type receiver struct {
pendingBufSize seqnum.Size
}
-func newReceiver(ep *endpoint, irs seqnum.Value, rcvWnd seqnum.Size, rcvWndScale uint8) *receiver {
+func newReceiver(ep *endpoint, irs seqnum.Value, rcvWnd seqnum.Size, rcvWndScale uint8, pendingBufSize seqnum.Size) *receiver {
return &receiver{
ep: ep,
rcvNxt: irs + 1,
rcvAcc: irs.Add(rcvWnd + 1),
+ rcvWnd: rcvWnd,
rcvWndScale: rcvWndScale,
- pendingBufSize: rcvWnd,
+ pendingBufSize: pendingBufSize,
}
}
@@ -72,14 +77,16 @@ func (r *receiver) acceptable(segSeq seqnum.Value, segLen seqnum.Size) bool {
// getSendParams returns the parameters needed by the sender when building
// segments to send.
func (r *receiver) getSendParams() (rcvNxt seqnum.Value, rcvWnd seqnum.Size) {
- // Calculate the window size based on the current buffer size.
- n := r.ep.receiveBufferAvailable()
- acc := r.rcvNxt.Add(seqnum.Size(n))
+ // Calculate the window size based on the available buffer space.
+ receiveBufferAvailable := r.ep.receiveBufferAvailable()
+ acc := r.rcvNxt.Add(seqnum.Size(receiveBufferAvailable))
if r.rcvAcc.LessThan(acc) {
r.rcvAcc = acc
}
-
- return r.rcvNxt, r.rcvNxt.Size(r.rcvAcc) >> r.rcvWndScale
+ // Stash away the non-scaled receive window as we use it for measuring
+ // receiver's estimated RTT.
+ r.rcvWnd = r.rcvNxt.Size(r.rcvAcc)
+ return r.rcvNxt, r.rcvWnd >> r.rcvWndScale
}
// nonZeroWindow is called when the receive window grows from zero to nonzero;
@@ -130,6 +137,21 @@ func (r *receiver) consumeSegment(s *segment, segSeq seqnum.Value, segLen seqnum
// Update the segment that we're expecting to consume.
r.rcvNxt = segSeq.Add(segLen)
+ // In cases of a misbehaving sender which could send more than the
+ // advertised window, we could end up in a situation where we get a
+ // segment that exceeds the window advertised. Instead of partially
+ // accepting the segment and discarding bytes beyond the advertised
+ // window, we accept the whole segment and make sure r.rcvAcc is moved
+ // forward to match r.rcvNxt to indicate that the window is now closed.
+ //
+ // In absence of this check the r.acceptable() check fails and accepts
+ // segments that should be dropped because rcvWnd is calculated as
+ // the size of the interval (rcvNxt, rcvAcc] which becomes extremely
+ // large if rcvAcc is ever less than rcvNxt.
+ if r.rcvAcc.LessThan(r.rcvNxt) {
+ r.rcvAcc = r.rcvNxt
+ }
+
// Trim SACK Blocks to remove any SACK information that covers
// sequence numbers that have been consumed.
TrimSACKBlockList(&r.ep.sack, r.rcvNxt)
@@ -198,6 +220,39 @@ func (r *receiver) consumeSegment(s *segment, segSeq seqnum.Value, segLen seqnum
return true
}
+// 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)
+ // We only store the minimum observed RTT here as this is only used in
+ // absence of a SRTT available from either timestamps or a sender
+ // measurement of RTT.
+ if r.ep.rcvAutoParams.rtt == 0 || rtt < r.ep.rcvAutoParams.rtt {
+ r.ep.rcvAutoParams.rtt = rtt
+ }
+ 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
// r as they arrive. It is called by the protocol main loop.
func (r *receiver) handleRcvdSegment(s *segment) {
@@ -226,10 +281,9 @@ func (r *receiver) handleRcvdSegment(s *segment) {
r.pendingBufUsed += s.logicalLen()
s.incRef()
heap.Push(&r.pendingRcvdSegments, s)
+ UpdateSACKBlocks(&r.ep.sack, segSeq, segSeq.Add(segLen), r.rcvNxt)
}
- UpdateSACKBlocks(&r.ep.sack, segSeq, segSeq.Add(segLen), r.rcvNxt)
-
// Immediately send an ack so that the peer knows it may
// have to retransmit.
r.ep.snd.sendAck()
@@ -237,6 +291,12 @@ func (r *receiver) handleRcvdSegment(s *segment) {
return
}
+ // Since we consumed a segment update the receiver's RTT estimate
+ // if required.
+ if segLen > 0 {
+ r.updateRTT()
+ }
+
// By consuming the current segment, we may have filled a gap in the
// sequence number domain that allows pending segments to be consumed
// now. So try to do it.
diff --git a/pkg/tcpip/transport/tcp/sack.go b/pkg/tcpip/transport/tcp/sack.go
index 52c5d9867..7be86d68e 100644
--- a/pkg/tcpip/transport/tcp/sack.go
+++ b/pkg/tcpip/transport/tcp/sack.go
@@ -31,6 +31,13 @@ const (
// segment identified by segStart->segEnd.
func UpdateSACKBlocks(sack *SACKInfo, segStart seqnum.Value, segEnd seqnum.Value, rcvNxt seqnum.Value) {
newSB := header.SACKBlock{Start: segStart, End: segEnd}
+
+ // Ignore any invalid SACK blocks or blocks that are before rcvNxt as
+ // those bytes have already been acked.
+ if newSB.End.LessThanEq(newSB.Start) || newSB.End.LessThan(rcvNxt) {
+ return
+ }
+
if sack.NumBlocks == 0 {
sack.Blocks[0] = newSB
sack.NumBlocks = 1
@@ -39,9 +46,8 @@ func UpdateSACKBlocks(sack *SACKInfo, segStart seqnum.Value, segEnd seqnum.Value
var n = 0
for i := 0; i < sack.NumBlocks; i++ {
start, end := sack.Blocks[i].Start, sack.Blocks[i].End
- if end.LessThanEq(start) || start.LessThanEq(rcvNxt) {
- // Discard any invalid blocks where end is before start
- // and discard any sack blocks that are before rcvNxt as
+ if end.LessThanEq(rcvNxt) {
+ // Discard any sack blocks that are before rcvNxt as
// those have already been acked.
continue
}
diff --git a/pkg/tcpip/transport/tcp/snd.go b/pkg/tcpip/transport/tcp/snd.go
index 297861462..0fee7ab72 100644
--- a/pkg/tcpip/transport/tcp/snd.go
+++ b/pkg/tcpip/transport/tcp/snd.go
@@ -121,9 +121,8 @@ type sender struct {
// rtt.srtt, rtt.rttvar, and rto are the "smoothed round-trip time",
// "round-trip time variation" and "retransmit timeout", as defined in
// section 2 of RFC 6298.
- rtt rtt
- rto time.Duration
- srttInited bool
+ rtt rtt
+ rto time.Duration
// maxPayloadSize is the maximum size of the payload of a given segment.
// It is initialized on demand.
@@ -150,8 +149,9 @@ type sender struct {
type rtt struct {
sync.Mutex `state:"nosave"`
- srtt time.Duration
- rttvar time.Duration
+ srtt time.Duration
+ rttvar time.Duration
+ srttInited bool
}
// fastRecovery holds information related to fast recovery from a packet loss.
@@ -323,10 +323,10 @@ func (s *sender) sendAck() {
// available. This is done in accordance with section 2 of RFC 6298.
func (s *sender) updateRTO(rtt time.Duration) {
s.rtt.Lock()
- if !s.srttInited {
+ if !s.rtt.srttInited {
s.rtt.rttvar = rtt / 2
s.rtt.srtt = rtt
- s.srttInited = true
+ s.rtt.srttInited = true
} else {
diff := s.rtt.srtt - rtt
if diff < 0 {
diff --git a/pkg/tcpip/transport/tcp/tcp_state_autogen.go b/pkg/tcpip/transport/tcp/tcp_state_autogen.go
index 1674c6a08..601ff758d 100755
--- a/pkg/tcpip/transport/tcp/tcp_state_autogen.go
+++ b/pkg/tcpip/transport/tcp/tcp_state_autogen.go
@@ -50,6 +50,31 @@ func (x *SACKInfo) load(m state.Map) {
m.Load("NumBlocks", &x.NumBlocks)
}
+func (x *rcvBufAutoTuneParams) beforeSave() {}
+func (x *rcvBufAutoTuneParams) save(m state.Map) {
+ x.beforeSave()
+ var measureTime unixTime = x.saveMeasureTime()
+ m.SaveValue("measureTime", measureTime)
+ var rttMeasureTime unixTime = x.saveRttMeasureTime()
+ m.SaveValue("rttMeasureTime", rttMeasureTime)
+ m.Save("copied", &x.copied)
+ m.Save("prevCopied", &x.prevCopied)
+ m.Save("rtt", &x.rtt)
+ m.Save("rttMeasureSeqNumber", &x.rttMeasureSeqNumber)
+ m.Save("disabled", &x.disabled)
+}
+
+func (x *rcvBufAutoTuneParams) afterLoad() {}
+func (x *rcvBufAutoTuneParams) load(m state.Map) {
+ m.Load("copied", &x.copied)
+ m.Load("prevCopied", &x.prevCopied)
+ m.Load("rtt", &x.rtt)
+ m.Load("rttMeasureSeqNumber", &x.rttMeasureSeqNumber)
+ m.Load("disabled", &x.disabled)
+ m.LoadValue("measureTime", new(unixTime), func(y interface{}) { x.loadMeasureTime(y.(unixTime)) })
+ m.LoadValue("rttMeasureTime", new(unixTime), func(y interface{}) { x.loadRttMeasureTime(y.(unixTime)) })
+}
+
func (x *endpoint) save(m state.Map) {
x.beforeSave()
var lastError string = x.saveLastError()
@@ -66,6 +91,7 @@ func (x *endpoint) save(m state.Map) {
m.Save("rcvClosed", &x.rcvClosed)
m.Save("rcvBufSize", &x.rcvBufSize)
m.Save("rcvBufUsed", &x.rcvBufUsed)
+ m.Save("rcvAutoParams", &x.rcvAutoParams)
m.Save("id", &x.id)
m.Save("isRegistered", &x.isRegistered)
m.Save("v6only", &x.v6only)
@@ -100,6 +126,7 @@ func (x *endpoint) save(m state.Map) {
m.Save("snd", &x.snd)
m.Save("bindAddress", &x.bindAddress)
m.Save("connectingAddress", &x.connectingAddress)
+ m.Save("amss", &x.amss)
m.Save("gso", &x.gso)
}
@@ -110,6 +137,7 @@ func (x *endpoint) load(m state.Map) {
m.Load("rcvClosed", &x.rcvClosed)
m.Load("rcvBufSize", &x.rcvBufSize)
m.Load("rcvBufUsed", &x.rcvBufUsed)
+ m.Load("rcvAutoParams", &x.rcvAutoParams)
m.Load("id", &x.id)
m.Load("isRegistered", &x.isRegistered)
m.Load("v6only", &x.v6only)
@@ -144,6 +172,7 @@ func (x *endpoint) load(m state.Map) {
m.LoadWait("snd", &x.snd)
m.Load("bindAddress", &x.bindAddress)
m.Load("connectingAddress", &x.connectingAddress)
+ m.Load("amss", &x.amss)
m.Load("gso", &x.gso)
m.LoadValue("lastError", new(string), func(y interface{}) { x.loadLastError(y.(string)) })
m.LoadValue("state", new(EndpointState), func(y interface{}) { x.loadState(y.(EndpointState)) })
@@ -177,6 +206,7 @@ func (x *receiver) save(m state.Map) {
m.Save("ep", &x.ep)
m.Save("rcvNxt", &x.rcvNxt)
m.Save("rcvAcc", &x.rcvAcc)
+ m.Save("rcvWnd", &x.rcvWnd)
m.Save("rcvWndScale", &x.rcvWndScale)
m.Save("closed", &x.closed)
m.Save("pendingRcvdSegments", &x.pendingRcvdSegments)
@@ -189,6 +219,7 @@ func (x *receiver) load(m state.Map) {
m.Load("ep", &x.ep)
m.Load("rcvNxt", &x.rcvNxt)
m.Load("rcvAcc", &x.rcvAcc)
+ m.Load("rcvWnd", &x.rcvWnd)
m.Load("rcvWndScale", &x.rcvWndScale)
m.Load("closed", &x.closed)
m.Load("pendingRcvdSegments", &x.pendingRcvdSegments)
@@ -302,7 +333,6 @@ func (x *sender) save(m state.Map) {
m.Save("writeList", &x.writeList)
m.Save("rtt", &x.rtt)
m.Save("rto", &x.rto)
- m.Save("srttInited", &x.srttInited)
m.Save("maxPayloadSize", &x.maxPayloadSize)
m.Save("gso", &x.gso)
m.Save("sndWndScale", &x.sndWndScale)
@@ -328,7 +358,6 @@ func (x *sender) load(m state.Map) {
m.Load("writeList", &x.writeList)
m.Load("rtt", &x.rtt)
m.Load("rto", &x.rto)
- m.Load("srttInited", &x.srttInited)
m.Load("maxPayloadSize", &x.maxPayloadSize)
m.Load("gso", &x.gso)
m.Load("sndWndScale", &x.sndWndScale)
@@ -344,12 +373,14 @@ func (x *rtt) save(m state.Map) {
x.beforeSave()
m.Save("srtt", &x.srtt)
m.Save("rttvar", &x.rttvar)
+ m.Save("srttInited", &x.srttInited)
}
func (x *rtt) afterLoad() {}
func (x *rtt) load(m state.Map) {
m.Load("srtt", &x.srtt)
m.Load("rttvar", &x.rttvar)
+ m.Load("srttInited", &x.srttInited)
}
func (x *fastRecovery) beforeSave() {}
@@ -415,6 +446,7 @@ func (x *segmentEntry) load(m state.Map) {
func init() {
state.Register("tcp.cubicState", (*cubicState)(nil), state.Fns{Save: (*cubicState).save, Load: (*cubicState).load})
state.Register("tcp.SACKInfo", (*SACKInfo)(nil), state.Fns{Save: (*SACKInfo).save, Load: (*SACKInfo).load})
+ state.Register("tcp.rcvBufAutoTuneParams", (*rcvBufAutoTuneParams)(nil), state.Fns{Save: (*rcvBufAutoTuneParams).save, Load: (*rcvBufAutoTuneParams).load})
state.Register("tcp.endpoint", (*endpoint)(nil), state.Fns{Save: (*endpoint).save, Load: (*endpoint).load})
state.Register("tcp.keepalive", (*keepalive)(nil), state.Fns{Save: (*keepalive).save, Load: (*keepalive).load})
state.Register("tcp.receiver", (*receiver)(nil), state.Fns{Save: (*receiver).save, Load: (*receiver).load})
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-04 16:00:21 +0000