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-rw-r--r--pkg/tcpip/transport/tcp/connect.go5
-rw-r--r--pkg/tcpip/transport/tcp/endpoint.go7
-rw-r--r--pkg/tcpip/transport/tcp/protocol.go5
-rw-r--r--pkg/tcpip/transport/tcp/rack.go76
-rw-r--r--pkg/tcpip/transport/tcp/rack_state.go5
-rw-r--r--pkg/tcpip/transport/tcp/snd.go3
-rw-r--r--test/syscalls/linux/proc_net.cc8
7 files changed, 105 insertions, 4 deletions
diff --git a/pkg/tcpip/transport/tcp/connect.go b/pkg/tcpip/transport/tcp/connect.go
index 0dc710276..a00ef97c6 100644
--- a/pkg/tcpip/transport/tcp/connect.go
+++ b/pkg/tcpip/transport/tcp/connect.go
@@ -1357,6 +1357,7 @@ func (e *endpoint) protocolMainLoop(handshake bool, wakerInitDone chan<- struct{
// e.mu is expected to be hold upon entering this section.
if e.snd != nil {
e.snd.resendTimer.cleanup()
+ e.snd.rc.probeTimer.cleanup()
}
if closeTimer != nil {
@@ -1437,6 +1438,10 @@ func (e *endpoint) protocolMainLoop(handshake bool, wakerInitDone chan<- struct{
},
},
{
+ w: &e.snd.rc.probeWaker,
+ f: e.snd.probeTimerExpired,
+ },
+ {
w: &e.newSegmentWaker,
f: func() *tcpip.Error {
return e.handleSegments(false /* fastPath */)
diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index 8f3981075..281f4cd58 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -508,6 +508,9 @@ type endpoint struct {
// shutdownFlags represent the current shutdown state of the endpoint.
shutdownFlags tcpip.ShutdownFlags
+ // tcpRecovery is the loss deteoction algorithm used by TCP.
+ tcpRecovery tcpip.TCPRecovery
+
// sackPermitted is set to true if the peer sends the TCPSACKPermitted
// option in the SYN/SYN-ACK.
sackPermitted bool
@@ -918,6 +921,8 @@ func newEndpoint(s *stack.Stack, netProto tcpip.NetworkProtocolNumber, waiterQue
e.maxSynRetries = uint8(synRetries)
}
+ s.TransportProtocolOption(ProtocolNumber, &e.tcpRecovery)
+
if p := s.GetTCPProbe(); p != nil {
e.probe = p
}
@@ -3072,7 +3077,7 @@ func (e *endpoint) completeState() stack.TCPEndpointState {
}
}
- rc := e.snd.rc
+ rc := &e.snd.rc
s.Sender.RACKState = stack.TCPRACKState{
XmitTime: rc.xmitTime,
EndSequence: rc.endSequence,
diff --git a/pkg/tcpip/transport/tcp/protocol.go b/pkg/tcpip/transport/tcp/protocol.go
index 672159eed..c9e194f82 100644
--- a/pkg/tcpip/transport/tcp/protocol.go
+++ b/pkg/tcpip/transport/tcp/protocol.go
@@ -405,7 +405,7 @@ func (p *protocol) Option(option tcpip.GettableTransportProtocolOption) *tcpip.E
case *tcpip.TCPRecovery:
p.mu.RLock()
- *v = tcpip.TCPRecovery(p.recovery)
+ *v = p.recovery
p.mu.RUnlock()
return nil
@@ -543,7 +543,8 @@ func NewProtocol(s *stack.Stack) stack.TransportProtocol {
minRTO: MinRTO,
maxRTO: MaxRTO,
maxRetries: MaxRetries,
- recovery: tcpip.TCPRACKLossDetection,
+ // TODO(gvisor.dev/issue/5243): Set recovery to tcpip.TCPRACKLossDetection.
+ recovery: 0,
}
p.dispatcher.init(runtime.GOMAXPROCS(0))
return &p
diff --git a/pkg/tcpip/transport/tcp/rack.go b/pkg/tcpip/transport/tcp/rack.go
index e0a50a919..b71e6b992 100644
--- a/pkg/tcpip/transport/tcp/rack.go
+++ b/pkg/tcpip/transport/tcp/rack.go
@@ -17,9 +17,18 @@ package tcp
import (
"time"
+ "gvisor.dev/gvisor/pkg/sleep"
+ "gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/seqnum"
)
+// wcDelayedACKTimeout is the recommended maximum delayed ACK timer value as
+// defined in https://tools.ietf.org/html/draft-ietf-tcpm-rack-08#section-7.5.
+// It stands for worst case delayed ACK timer (WCDelAckT). When FlightSize is
+// 1, PTO is inflated by WCDelAckT time to compensate for a potential long
+// delayed ACK timer at the receiver.
+const wcDelayedACKTimeout = 200 * time.Millisecond
+
// 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.
@@ -54,6 +63,15 @@ type rackControl struct {
// xmitTime is the latest transmission timestamp of rackControl.seg.
xmitTime time.Time `state:".(unixTime)"`
+
+ // probeTimer and probeWaker are used to schedule PTO for RACK TLP algorithm.
+ probeTimer timer `state:"nosave"`
+ probeWaker sleep.Waker `state:"nosave"`
+}
+
+// init initializes RACK specific fields.
+func (rc *rackControl) init() {
+ rc.probeTimer.init(&rc.probeWaker)
}
// update will update the RACK related fields when an ACK has been received.
@@ -127,3 +145,61 @@ func (rc *rackControl) detectReorder(seg *segment) {
func (rc *rackControl) setDSACKSeen() {
rc.dsackSeen = true
}
+
+// shouldSchedulePTO dictates whether we should schedule a PTO or not.
+// See https://tools.ietf.org/html/draft-ietf-tcpm-rack-08#section-7.5.1.
+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 &&
+ // The connection is not in loss recovery.
+ (s.state != RTORecovery && s.state != SACKRecovery) &&
+ // The connection has no SACKed sequences in the SACK scoreboard.
+ s.ep.scoreboard.Sacked() == 0
+}
+
+// schedulePTO schedules the probe timeout as defined in
+// https://tools.ietf.org/html/draft-ietf-tcpm-rack-08#section-7.5.1.
+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 {
+ pto += wcDelayedACKTimeout
+ }
+ }
+ s.rtt.Unlock()
+
+ now := time.Now()
+ if s.resendTimer.enabled() {
+ if now.Add(pto).After(s.resendTimer.target) {
+ pto = s.resendTimer.target.Sub(now)
+ }
+ s.resendTimer.disable()
+ }
+
+ s.rc.probeTimer.enable(pto)
+}
+
+// probeTimerExpired is the same as TLP_send_probe() as defined in
+// https://tools.ietf.org/html/draft-ietf-tcpm-rack-08#section-7.5.2.
+func (s *sender) probeTimerExpired() *tcpip.Error {
+ if !s.rc.probeTimer.checkExpiration() {
+ return nil
+ }
+ // TODO(gvisor.dev/issue/5084): Implement this pseudo algorithm.
+ // If an unsent segment exists AND
+ // the receive window allows new data to be sent:
+ // Transmit the lowest-sequence unsent segment of up to SMSS
+ // Increment FlightSize by the size of the newly-sent segment
+ // Else if TLPRxtOut is not set:
+ // Retransmit the highest-sequence segment sent so far
+ // TLPRxtOut = true
+ // TLPHighRxt = SND.NXT
+ // The cwnd remains unchanged
+ // If FlightSize != 0:
+ // Arm RTO timer only.
+ return nil
+}
diff --git a/pkg/tcpip/transport/tcp/rack_state.go b/pkg/tcpip/transport/tcp/rack_state.go
index c9dc7e773..76cad0831 100644
--- a/pkg/tcpip/transport/tcp/rack_state.go
+++ b/pkg/tcpip/transport/tcp/rack_state.go
@@ -27,3 +27,8 @@ func (rc *rackControl) saveXmitTime() unixTime {
func (rc *rackControl) loadXmitTime(unix unixTime) {
rc.xmitTime = time.Unix(unix.second, unix.nano)
}
+
+// afterLoad is invoked by stateify.
+func (rc *rackControl) afterLoad() {
+ rc.probeTimer.init(&rc.probeWaker)
+}
diff --git a/pkg/tcpip/transport/tcp/snd.go b/pkg/tcpip/transport/tcp/snd.go
index cc991aba6..c0e9d98e3 100644
--- a/pkg/tcpip/transport/tcp/snd.go
+++ b/pkg/tcpip/transport/tcp/snd.go
@@ -286,6 +286,8 @@ func newSender(ep *endpoint, iss, irs seqnum.Value, sndWnd seqnum.Size, mss uint
gso: ep.gso != nil,
}
+ s.rc.init()
+
if s.gso {
s.ep.gso.MSS = uint16(maxPayloadSize)
}
@@ -1455,6 +1457,7 @@ func (s *sender) handleRcvdSegment(rcvdSeg *segment) {
// Reset firstRetransmittedSegXmitTime to the zero value.
s.firstRetransmittedSegXmitTime = time.Time{}
s.resendTimer.disable()
+ s.rc.probeTimer.disable()
}
}
diff --git a/test/syscalls/linux/proc_net.cc b/test/syscalls/linux/proc_net.cc
index 1cc700fe7..73140b2e9 100644
--- a/test/syscalls/linux/proc_net.cc
+++ b/test/syscalls/linux/proc_net.cc
@@ -499,7 +499,13 @@ TEST(ProcSysNetIpv4Recovery, CanReadAndWrite) {
// Check initial value is set to 1.
EXPECT_THAT(PreadFd(fd.get(), &buf, sizeof(buf), 0),
SyscallSucceedsWithValue(sizeof(to_write) + 1));
- EXPECT_EQ(strcmp(buf, "1\n"), 0);
+ if (IsRunningOnGvisor()) {
+ // TODO(gvisor.dev/issue/5243): TCPRACKLossDetection = 1 should be turned on
+ // by default.
+ EXPECT_EQ(strcmp(buf, "0\n"), 0);
+ } else {
+ EXPECT_EQ(strcmp(buf, "1\n"), 0);
+ }
// Set tcp_recovery to one of the allowed constants.
EXPECT_THAT(PwriteFd(fd.get(), &to_write, sizeof(to_write), 0),
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-08 18:37:56 +0000