diff options
Diffstat (limited to 'pkg/tcpip/transport')
| -rw-r--r-- | pkg/tcpip/transport/tcp/BUILD | 3 | ||||
| -rw-r--r-- | pkg/tcpip/transport/tcp/accept.go | 2 | ||||
| -rw-r--r-- | pkg/tcpip/transport/tcp/connect.go | 13 | ||||
| -rw-r--r-- | pkg/tcpip/transport/tcp/endpoint.go | 15 | ||||
| -rw-r--r-- | pkg/tcpip/transport/tcp/rack.go | 82 | ||||
| -rw-r--r-- | pkg/tcpip/transport/tcp/rack_state.go | 29 | ||||
| -rw-r--r-- | pkg/tcpip/transport/tcp/snd.go | 40 | ||||
| -rw-r--r-- | pkg/tcpip/transport/tcp/tcp_rack_test.go | 74 |
8 files changed, 235 insertions, 23 deletions
diff --git a/pkg/tcpip/transport/tcp/BUILD b/pkg/tcpip/transport/tcp/BUILD index e860ee484..234fb95ce 100644 --- a/pkg/tcpip/transport/tcp/BUILD +++ b/pkg/tcpip/transport/tcp/BUILD @@ -40,6 +40,8 @@ go_library( "endpoint_state.go", "forwarder.go", "protocol.go", + "rack.go", + "rack_state.go", "rcv.go", "rcv_state.go", "reno.go", @@ -83,6 +85,7 @@ go_test( "dual_stack_test.go", "sack_scoreboard_test.go", "tcp_noracedetector_test.go", + "tcp_rack_test.go", "tcp_sack_test.go", "tcp_test.go", "tcp_timestamp_test.go", diff --git a/pkg/tcpip/transport/tcp/accept.go b/pkg/tcpip/transport/tcp/accept.go index 6e00e5526..913ea6535 100644 --- a/pkg/tcpip/transport/tcp/accept.go +++ b/pkg/tcpip/transport/tcp/accept.go @@ -521,7 +521,7 @@ func (e *endpoint) handleListenSegment(ctx *listenContext, s *segment) { synOpts := header.TCPSynOptions{ WS: -1, TS: opts.TS, - TSVal: tcpTimeStamp(timeStampOffset()), + TSVal: tcpTimeStamp(time.Now(), timeStampOffset()), TSEcr: opts.TSVal, MSS: mssForRoute(&s.route), } diff --git a/pkg/tcpip/transport/tcp/connect.go b/pkg/tcpip/transport/tcp/connect.go index 6e5e55b6f..8dd759ba2 100644 --- a/pkg/tcpip/transport/tcp/connect.go +++ b/pkg/tcpip/transport/tcp/connect.go @@ -1166,13 +1166,18 @@ func (e *endpoint) handleSegments(fastPath bool) *tcpip.Error { return nil } -// handleSegment handles a given segment and notifies the worker goroutine if -// if the connection should be terminated. -func (e *endpoint) handleSegment(s *segment) (cont bool, err *tcpip.Error) { - // Invoke the tcp probe if installed. +func (e *endpoint) probeSegment() { if e.probe != nil { e.probe(e.completeState()) } +} + +// handleSegment handles a given segment and notifies the worker goroutine if +// if the connection should be terminated. +func (e *endpoint) handleSegment(s *segment) (cont bool, err *tcpip.Error) { + // Invoke the tcp probe if installed. The tcp probe function will update + // the TCPEndpointState after the segment is processed. + defer e.probeSegment() if s.flagIsSet(header.TCPFlagRst) { if ok, err := e.handleReset(s); !ok { diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go index 682687ebe..39ea38fe6 100644 --- a/pkg/tcpip/transport/tcp/endpoint.go +++ b/pkg/tcpip/transport/tcp/endpoint.go @@ -2692,15 +2692,14 @@ func (e *endpoint) maybeEnableTimestamp(synOpts *header.TCPSynOptions) { // timestamp returns the timestamp value to be used in the TSVal field of the // timestamp option for outgoing TCP segments for a given endpoint. func (e *endpoint) timestamp() uint32 { - return tcpTimeStamp(e.tsOffset) + return tcpTimeStamp(time.Now(), e.tsOffset) } // tcpTimeStamp returns a timestamp offset by the provided offset. This is // not inlined above as it's used when SYN cookies are in use and endpoint // is not created at the time when the SYN cookie is sent. -func tcpTimeStamp(offset uint32) uint32 { - now := time.Now() - return uint32(now.Unix()*1000+int64(now.Nanosecond()/1e6)) + offset +func tcpTimeStamp(curTime time.Time, offset uint32) uint32 { + return uint32(curTime.Unix()*1000+int64(curTime.Nanosecond()/1e6)) + offset } // timeStampOffset returns a randomized timestamp offset to be used when sending @@ -2843,6 +2842,14 @@ func (e *endpoint) completeState() stack.TCPEndpointState { WEst: cubic.wEst, } } + + rc := e.snd.rc + s.Sender.RACKState = stack.TCPRACKState{ + XmitTime: rc.xmitTime, + EndSequence: rc.endSequence, + FACK: rc.fack, + RTT: rc.rtt, + } return s } diff --git a/pkg/tcpip/transport/tcp/rack.go b/pkg/tcpip/transport/tcp/rack.go new file mode 100644 index 000000000..d969ca23a --- /dev/null +++ b/pkg/tcpip/transport/tcp/rack.go @@ -0,0 +1,82 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tcp + +import ( + "time" + + "gvisor.dev/gvisor/pkg/tcpip/seqnum" +) + +// RACK is a loss detection algorithm used in TCP to detect packet loss and +// reordering using transmission timestamp of the packets instead of packet or +// sequence counts. To use RACK, SACK should be enabled on the connection. + +// rackControl stores the rack related fields. +// See: https://tools.ietf.org/html/draft-ietf-tcpm-rack-08#section-6.1 +// +// +stateify savable +type rackControl struct { + // xmitTime is the latest transmission timestamp of rackControl.seg. + xmitTime time.Time `state:".(unixTime)"` + + // endSequence is the ending TCP sequence number of rackControl.seg. + endSequence seqnum.Value + + // fack is the highest selectively or cumulatively acknowledged + // sequence. + fack seqnum.Value + + // 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 +} + +// Update will update the RACK related fields when an ACK has been received. +// See: https://tools.ietf.org/html/draft-ietf-tcpm-rack-08#section-7.2 +func (rc *rackControl) Update(seg *segment, ackSeg *segment, srtt time.Duration, offset uint32) { + rtt := time.Now().Sub(seg.xmitTime) + + // If the ACK is for a retransmitted packet, do not update if it is a + // spurious inference which is determined by below checks: + // 1. When Timestamping option is available, if the TSVal is less than the + // transmit time of the most recent retransmitted packet. + // 2. When RTT calculated for the packet is less than the smoothed RTT + // for the connection. + // See: https://tools.ietf.org/html/draft-ietf-tcpm-rack-08#section-7.2 + // step 2 + if seg.xmitCount > 1 { + if ackSeg.parsedOptions.TS && ackSeg.parsedOptions.TSEcr != 0 { + if ackSeg.parsedOptions.TSEcr < tcpTimeStamp(seg.xmitTime, offset) { + return + } + } + if rtt < srtt { + return + } + } + + rc.rtt = rtt + // Update rc.xmitTime and rc.endSequence to the transmit time and + // 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 + } +} diff --git a/pkg/tcpip/transport/tcp/rack_state.go b/pkg/tcpip/transport/tcp/rack_state.go new file mode 100644 index 000000000..c9dc7e773 --- /dev/null +++ b/pkg/tcpip/transport/tcp/rack_state.go @@ -0,0 +1,29 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tcp + +import ( + "time" +) + +// saveXmitTime is invoked by stateify. +func (rc *rackControl) saveXmitTime() unixTime { + return unixTime{rc.xmitTime.Unix(), rc.xmitTime.UnixNano()} +} + +// loadXmitTime is invoked by stateify. +func (rc *rackControl) loadXmitTime(unix unixTime) { + rc.xmitTime = time.Unix(unix.second, unix.nano) +} diff --git a/pkg/tcpip/transport/tcp/snd.go b/pkg/tcpip/transport/tcp/snd.go index 5862c32f2..c55589c45 100644 --- a/pkg/tcpip/transport/tcp/snd.go +++ b/pkg/tcpip/transport/tcp/snd.go @@ -191,6 +191,10 @@ type sender struct { // cc is the congestion control algorithm in use for this sender. cc congestionControl + + // rc has the fields needed for implementing RACK loss detection + // algorithm. + rc rackControl } // rtt is a synchronization wrapper used to appease stateify. See the comment @@ -1272,21 +1276,21 @@ func (s *sender) checkDuplicateAck(seg *segment) (rtx bool) { // handleRcvdSegment is called when a segment is received; it is responsible for // updating the send-related state. -func (s *sender) handleRcvdSegment(seg *segment) { +func (s *sender) handleRcvdSegment(rcvdSeg *segment) { // Check if we can extract an RTT measurement from this ack. - if !seg.parsedOptions.TS && s.rttMeasureSeqNum.LessThan(seg.ackNumber) { + if !rcvdSeg.parsedOptions.TS && s.rttMeasureSeqNum.LessThan(rcvdSeg.ackNumber) { s.updateRTO(time.Now().Sub(s.rttMeasureTime)) s.rttMeasureSeqNum = s.sndNxt } // Update Timestamp if required. See RFC7323, section-4.3. - if s.ep.sendTSOk && seg.parsedOptions.TS { - s.ep.updateRecentTimestamp(seg.parsedOptions.TSVal, s.maxSentAck, seg.sequenceNumber) + if s.ep.sendTSOk && rcvdSeg.parsedOptions.TS { + s.ep.updateRecentTimestamp(rcvdSeg.parsedOptions.TSVal, s.maxSentAck, rcvdSeg.sequenceNumber) } // Insert SACKBlock information into our scoreboard. if s.ep.sackPermitted { - for _, sb := range seg.parsedOptions.SACKBlocks { + for _, sb := range rcvdSeg.parsedOptions.SACKBlocks { // Only insert the SACK block if the following holds // true: // * SACK block acks data after the ack number in the @@ -1299,27 +1303,27 @@ func (s *sender) handleRcvdSegment(seg *segment) { // NOTE: This check specifically excludes DSACK blocks // which have start/end before sndUna and are used to // indicate spurious retransmissions. - if seg.ackNumber.LessThan(sb.Start) && s.sndUna.LessThan(sb.Start) && sb.End.LessThanEq(s.sndNxt) && !s.ep.scoreboard.IsSACKED(sb) { + if rcvdSeg.ackNumber.LessThan(sb.Start) && s.sndUna.LessThan(sb.Start) && sb.End.LessThanEq(s.sndNxt) && !s.ep.scoreboard.IsSACKED(sb) { s.ep.scoreboard.Insert(sb) - seg.hasNewSACKInfo = true + rcvdSeg.hasNewSACKInfo = true } } s.SetPipe() } // Count the duplicates and do the fast retransmit if needed. - rtx := s.checkDuplicateAck(seg) + rtx := s.checkDuplicateAck(rcvdSeg) // Stash away the current window size. - s.sndWnd = seg.window + s.sndWnd = rcvdSeg.window - ack := seg.ackNumber + ack := rcvdSeg.ackNumber // Disable zero window probing if remote advertizes a non-zero receive // window. This can be with an ACK to the zero window probe (where the // acknumber refers to the already acknowledged byte) OR to any previously // unacknowledged segment. - if s.zeroWindowProbing && seg.window > 0 && + if s.zeroWindowProbing && rcvdSeg.window > 0 && (ack == s.sndUna || (ack-1).InRange(s.sndUna, s.sndNxt)) { s.disableZeroWindowProbing() } @@ -1344,10 +1348,10 @@ func (s *sender) handleRcvdSegment(seg *segment) { // averaged RTT measurement only if the segment acknowledges // some new data, i.e., only if it advances the left edge of // the send window. - if s.ep.sendTSOk && seg.parsedOptions.TSEcr != 0 { + if s.ep.sendTSOk && rcvdSeg.parsedOptions.TSEcr != 0 { // TSVal/Ecr values sent by Netstack are at a millisecond // granularity. - elapsed := time.Duration(s.ep.timestamp()-seg.parsedOptions.TSEcr) * time.Millisecond + elapsed := time.Duration(s.ep.timestamp()-rcvdSeg.parsedOptions.TSEcr) * time.Millisecond s.updateRTO(elapsed) } @@ -1361,6 +1365,9 @@ func (s *sender) handleRcvdSegment(seg *segment) { ackLeft := acked originalOutstanding := s.outstanding + s.rtt.Lock() + srtt := s.rtt.srtt + s.rtt.Unlock() for ackLeft > 0 { // We use logicalLen here because we can have FIN // segments (which are always at the end of list) that @@ -1380,6 +1387,11 @@ func (s *sender) handleRcvdSegment(seg *segment) { s.writeNext = seg.Next() } + // Update the RACK fields if SACK is enabled. + if s.ep.sackPermitted { + s.rc.Update(seg, rcvdSeg, srtt, s.ep.tsOffset) + } + s.writeList.Remove(seg) // if SACK is enabled then Only reduce outstanding if @@ -1435,7 +1447,7 @@ func (s *sender) handleRcvdSegment(seg *segment) { // that the window opened up, or the congestion window was inflated due // to a duplicate ack during fast recovery. This will also re-enable // the retransmit timer if needed. - if !s.ep.sackPermitted || s.fr.active || s.dupAckCount == 0 || seg.hasNewSACKInfo { + if !s.ep.sackPermitted || s.fr.active || s.dupAckCount == 0 || rcvdSeg.hasNewSACKInfo { s.sendData() } } diff --git a/pkg/tcpip/transport/tcp/tcp_rack_test.go b/pkg/tcpip/transport/tcp/tcp_rack_test.go new file mode 100644 index 000000000..e03f101e8 --- /dev/null +++ b/pkg/tcpip/transport/tcp/tcp_rack_test.go @@ -0,0 +1,74 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package tcp_test + +import ( + "testing" + "time" + + "gvisor.dev/gvisor/pkg/tcpip" + "gvisor.dev/gvisor/pkg/tcpip/buffer" + "gvisor.dev/gvisor/pkg/tcpip/header" + "gvisor.dev/gvisor/pkg/tcpip/stack" + "gvisor.dev/gvisor/pkg/tcpip/transport/tcp/testing/context" +) + +// TestRACKUpdate tests the RACK related fields are updated when an ACK is +// received on a SACK enabled connection. +func TestRACKUpdate(t *testing.T) { + const maxPayload = 10 + const tsOptionSize = 12 + const maxTCPOptionSize = 40 + + c := context.New(t, uint32(header.TCPMinimumSize+header.IPv4MinimumSize+maxTCPOptionSize+maxPayload)) + defer c.Cleanup() + + var xmitTime time.Time + c.Stack().AddTCPProbe(func(state stack.TCPEndpointState) { + // Validate that the endpoint Sender.RACKState is what we expect. + if state.Sender.RACKState.XmitTime.Before(xmitTime) { + t.Fatalf("RACK transmit time failed to update when an ACK is received") + } + + gotSeq := state.Sender.RACKState.EndSequence + wantSeq := state.Sender.SndNxt + if !gotSeq.LessThanEq(wantSeq) || gotSeq.LessThan(wantSeq) { + t.Fatalf("RACK sequence number failed to update, got: %v, but want: %v", gotSeq, wantSeq) + } + + if state.Sender.RACKState.RTT == 0 { + t.Fatalf("RACK RTT failed to update when an ACK is received") + } + }) + setStackSACKPermitted(t, c, true) + createConnectedWithSACKAndTS(c) + + data := buffer.NewView(maxPayload) + for i := range data { + data[i] = byte(i) + } + + // Write the data. + xmitTime = time.Now() + if _, _, err := c.EP.Write(tcpip.SlicePayload(data), tcpip.WriteOptions{}); err != nil { + t.Fatalf("Write failed: %s", err) + } + + bytesRead := 0 + c.ReceiveAndCheckPacketWithOptions(data, bytesRead, maxPayload, tsOptionSize) + bytesRead += maxPayload + c.SendAck(790, bytesRead) + time.Sleep(200 * time.Millisecond) +} |