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-rw-r--r--pkg/abi/linux/linux_abi_autogen_unsafe.go12
-rw-r--r--pkg/sentry/kernel/kernel.go5
-rw-r--r--pkg/sentry/kernel/time/tcpip.go131
-rw-r--r--pkg/tcpip/stack/ndp.go140
-rw-r--r--pkg/tcpip/stack/stack.go12
-rw-r--r--pkg/tcpip/tcpip.go27
-rw-r--r--pkg/tcpip/time_unsafe.go30
-rw-r--r--pkg/tcpip/timer.go147
-rw-r--r--pkg/tcpip/transport/icmp/endpoint.go2
-rw-r--r--pkg/tcpip/transport/packet/endpoint.go2
-rw-r--r--pkg/tcpip/transport/raw/endpoint.go2
-rw-r--r--pkg/tcpip/transport/udp/endpoint.go2
12 files changed, 371 insertions, 141 deletions
diff --git a/pkg/abi/linux/linux_abi_autogen_unsafe.go b/pkg/abi/linux/linux_abi_autogen_unsafe.go
index 6ea96906a..d8cc7aad0 100644
--- a/pkg/abi/linux/linux_abi_autogen_unsafe.go
+++ b/pkg/abi/linux/linux_abi_autogen_unsafe.go
@@ -135,12 +135,12 @@ func (s *Statx) UnmarshalBytes(src []byte) {
// Packed implements marshal.Marshallable.Packed.
//go:nosplit
func (s *Statx) Packed() bool {
- return s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed()
+ return s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed()
}
// MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
func (s *Statx) MarshalUnsafe(dst []byte) {
- if s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() {
+ if s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() {
safecopy.CopyIn(dst, unsafe.Pointer(s))
} else {
s.MarshalBytes(dst)
@@ -159,7 +159,7 @@ func (s *Statx) UnmarshalUnsafe(src []byte) {
// CopyOutN implements marshal.Marshallable.CopyOutN.
//go:nosplit
func (s *Statx) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
- if !s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() {
+ if !s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() {
// Type Statx doesn't have a packed layout in memory, fall back to MarshalBytes.
buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay.
s.MarshalBytes(buf) // escapes: fallback.
@@ -808,7 +808,7 @@ func (i *IPTIP) MarshalUnsafe(dst []byte) {
// UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
func (i *IPTIP) UnmarshalUnsafe(src []byte) {
- if i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
+ if i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() {
safecopy.CopyOut(unsafe.Pointer(i), src)
} else {
i.UnmarshalBytes(src)
@@ -848,7 +848,7 @@ func (i *IPTIP) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
// CopyIn implements marshal.Marshallable.CopyIn.
//go:nosplit
func (i *IPTIP) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
- if !i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
+ if !i.SrcMask.Packed() && i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() {
// Type IPTIP doesn't have a packed layout in memory, fall back to UnmarshalBytes.
buf := task.CopyScratchBuffer(i.SizeBytes()) // escapes: okay.
length, err := task.CopyInBytes(addr, buf) // escapes: okay.
@@ -874,7 +874,7 @@ func (i *IPTIP) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
// WriteTo implements io.WriterTo.WriteTo.
func (i *IPTIP) WriteTo(w io.Writer) (int64, error) {
- if !i.DstMask.Packed() && i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() {
+ if !i.Src.Packed() && i.Dst.Packed() && i.SrcMask.Packed() && i.DstMask.Packed() {
// Type IPTIP doesn't have a packed layout in memory, fall back to MarshalBytes.
buf := make([]byte, i.SizeBytes())
i.MarshalBytes(buf)
diff --git a/pkg/sentry/kernel/kernel.go b/pkg/sentry/kernel/kernel.go
index 240cd6fe0..15dae0f5b 100644
--- a/pkg/sentry/kernel/kernel.go
+++ b/pkg/sentry/kernel/kernel.go
@@ -1469,6 +1469,11 @@ func (k *Kernel) NowMonotonic() int64 {
return now
}
+// AfterFunc implements tcpip.Clock.AfterFunc.
+func (k *Kernel) AfterFunc(d time.Duration, f func()) tcpip.Timer {
+ return ktime.TcpipAfterFunc(k.realtimeClock, d, f)
+}
+
// SetMemoryFile sets Kernel.mf. SetMemoryFile must be called before Init or
// LoadFrom.
func (k *Kernel) SetMemoryFile(mf *pgalloc.MemoryFile) {
diff --git a/pkg/sentry/kernel/time/tcpip.go b/pkg/sentry/kernel/time/tcpip.go
new file mode 100644
index 000000000..c4474c0cf
--- /dev/null
+++ b/pkg/sentry/kernel/time/tcpip.go
@@ -0,0 +1,131 @@
+// 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 time
+
+import (
+ "sync"
+ "time"
+)
+
+// TcpipAfterFunc waits for duration to elapse according to clock then runs fn.
+// The timer is started immediately and will fire exactly once.
+func TcpipAfterFunc(clock Clock, duration time.Duration, fn func()) *TcpipTimer {
+ timer := &TcpipTimer{
+ clock: clock,
+ }
+ timer.notifier = functionNotifier{
+ fn: func() {
+ // tcpip.Timer.Stop() explicitly states that the function is called in a
+ // separate goroutine that Stop() does not synchronize with.
+ // Timer.Destroy() synchronizes with calls to TimerListener.Notify().
+ // This is semantically meaningful because, in the former case, it's
+ // legal to call tcpip.Timer.Stop() while holding locks that may also be
+ // taken by the function, but this isn't so in the latter case. Most
+ // immediately, Timer calls TimerListener.Notify() while holding
+ // Timer.mu. A deadlock occurs without spawning a goroutine:
+ // T1: (Timer expires)
+ // => Timer.Tick() <- Timer.mu.Lock() called
+ // => TimerListener.Notify()
+ // => Timer.Stop()
+ // => Timer.Destroy() <- Timer.mu.Lock() called, deadlock!
+ //
+ // Spawning a goroutine avoids the deadlock:
+ // T1: (Timer expires)
+ // => Timer.Tick() <- Timer.mu.Lock() called
+ // => TimerListener.Notify() <- Launches T2
+ // T2:
+ // => Timer.Stop()
+ // => Timer.Destroy() <- Timer.mu.Lock() called, blocks
+ // T1:
+ // => (returns) <- Timer.mu.Unlock() called
+ // T2:
+ // => (continues) <- No deadlock!
+ go func() {
+ timer.Stop()
+ fn()
+ }()
+ },
+ }
+ timer.Reset(duration)
+ return timer
+}
+
+// TcpipTimer is a resettable timer with variable duration expirations.
+// Implements tcpip.Timer, which does not define a Destroy method; instead, all
+// resources are released after timer expiration and calls to Timer.Stop.
+//
+// Must be created by AfterFunc.
+type TcpipTimer struct {
+ // clock is the time source. clock is immutable.
+ clock Clock
+
+ // notifier is called when the Timer expires. notifier is immutable.
+ notifier functionNotifier
+
+ // mu protects t.
+ mu sync.Mutex
+
+ // t stores the latest running Timer. This is replaced whenever Reset is
+ // called since Timer cannot be restarted once it has been Destroyed by Stop.
+ //
+ // This field is nil iff Stop has been called.
+ t *Timer
+}
+
+// Stop implements tcpip.Timer.Stop.
+func (r *TcpipTimer) Stop() bool {
+ r.mu.Lock()
+ defer r.mu.Unlock()
+
+ if r.t == nil {
+ return false
+ }
+ _, lastSetting := r.t.Swap(Setting{})
+ r.t.Destroy()
+ r.t = nil
+ return lastSetting.Enabled
+}
+
+// Reset implements tcpip.Timer.Reset.
+func (r *TcpipTimer) Reset(d time.Duration) {
+ r.mu.Lock()
+ defer r.mu.Unlock()
+
+ if r.t == nil {
+ r.t = NewTimer(r.clock, &r.notifier)
+ }
+
+ r.t.Swap(Setting{
+ Enabled: true,
+ Period: 0,
+ Next: r.clock.Now().Add(d),
+ })
+}
+
+// functionNotifier is a TimerListener that runs a function.
+//
+// functionNotifier cannot be saved or loaded.
+type functionNotifier struct {
+ fn func()
+}
+
+// Notify implements ktime.TimerListener.Notify.
+func (f *functionNotifier) Notify(uint64, Setting) (Setting, bool) {
+ f.fn()
+ return Setting{}, false
+}
+
+// Destroy implements ktime.TimerListener.Destroy.
+func (f *functionNotifier) Destroy() {}
diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go
index e28c23d66..9dce11a97 100644
--- a/pkg/tcpip/stack/ndp.go
+++ b/pkg/tcpip/stack/ndp.go
@@ -469,7 +469,7 @@ type ndpState struct {
rtrSolicit struct {
// The timer used to send the next router solicitation message.
- timer *time.Timer
+ timer tcpip.Timer
// Used to let the Router Solicitation timer know that it has been stopped.
//
@@ -503,7 +503,7 @@ type ndpState struct {
// to the DAD goroutine that DAD should stop.
type dadState struct {
// The DAD timer to send the next NS message, or resolve the address.
- timer *time.Timer
+ timer tcpip.Timer
// Used to let the DAD timer know that it has been stopped.
//
@@ -515,38 +515,38 @@ type dadState struct {
// defaultRouterState holds data associated with a default router discovered by
// a Router Advertisement (RA).
type defaultRouterState struct {
- // Timer to invalidate the default router.
+ // Job to invalidate the default router.
//
// Must not be nil.
- invalidationTimer *tcpip.CancellableTimer
+ invalidationJob *tcpip.Job
}
// onLinkPrefixState holds data associated with an on-link prefix discovered by
// a Router Advertisement's Prefix Information option (PI) when the NDP
// configurations was configured to do so.
type onLinkPrefixState struct {
- // Timer to invalidate the on-link prefix.
+ // Job to invalidate the on-link prefix.
//
// Must not be nil.
- invalidationTimer *tcpip.CancellableTimer
+ invalidationJob *tcpip.Job
}
// tempSLAACAddrState holds state associated with a temporary SLAAC address.
type tempSLAACAddrState struct {
- // Timer to deprecate the temporary SLAAC address.
+ // Job to deprecate the temporary SLAAC address.
//
// Must not be nil.
- deprecationTimer *tcpip.CancellableTimer
+ deprecationJob *tcpip.Job
- // Timer to invalidate the temporary SLAAC address.
+ // Job to invalidate the temporary SLAAC address.
//
// Must not be nil.
- invalidationTimer *tcpip.CancellableTimer
+ invalidationJob *tcpip.Job
- // Timer to regenerate the temporary SLAAC address.
+ // Job to regenerate the temporary SLAAC address.
//
// Must not be nil.
- regenTimer *tcpip.CancellableTimer
+ regenJob *tcpip.Job
createdAt time.Time
@@ -561,15 +561,15 @@ type tempSLAACAddrState struct {
// slaacPrefixState holds state associated with a SLAAC prefix.
type slaacPrefixState struct {
- // Timer to deprecate the prefix.
+ // Job to deprecate the prefix.
//
// Must not be nil.
- deprecationTimer *tcpip.CancellableTimer
+ deprecationJob *tcpip.Job
- // Timer to invalidate the prefix.
+ // Job to invalidate the prefix.
//
// Must not be nil.
- invalidationTimer *tcpip.CancellableTimer
+ invalidationJob *tcpip.Job
// Nonzero only when the address is not valid forever.
validUntil time.Time
@@ -651,12 +651,12 @@ func (ndp *ndpState) startDuplicateAddressDetection(addr tcpip.Address, ref *ref
}
var done bool
- var timer *time.Timer
+ var timer tcpip.Timer
// We initially start a timer to fire immediately because some of the DAD work
// cannot be done while holding the NIC's lock. This is effectively the same
// as starting a goroutine but we use a timer that fires immediately so we can
// reset it for the next DAD iteration.
- timer = time.AfterFunc(0, func() {
+ timer = ndp.nic.stack.Clock().AfterFunc(0, func() {
ndp.nic.mu.Lock()
defer ndp.nic.mu.Unlock()
@@ -871,9 +871,9 @@ func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) {
case ok && rl != 0:
// This is an already discovered default router. Update
- // the invalidation timer.
- rtr.invalidationTimer.StopLocked()
- rtr.invalidationTimer.Reset(rl)
+ // the invalidation job.
+ rtr.invalidationJob.Cancel()
+ rtr.invalidationJob.Schedule(rl)
ndp.defaultRouters[ip] = rtr
case ok && rl == 0:
@@ -950,7 +950,7 @@ func (ndp *ndpState) invalidateDefaultRouter(ip tcpip.Address) {
return
}
- rtr.invalidationTimer.StopLocked()
+ rtr.invalidationJob.Cancel()
delete(ndp.defaultRouters, ip)
// Let the integrator know a discovered default router is invalidated.
@@ -979,12 +979,12 @@ func (ndp *ndpState) rememberDefaultRouter(ip tcpip.Address, rl time.Duration) {
}
state := defaultRouterState{
- invalidationTimer: tcpip.NewCancellableTimer(&ndp.nic.mu, func() {
+ invalidationJob: ndp.nic.stack.newJob(&ndp.nic.mu, func() {
ndp.invalidateDefaultRouter(ip)
}),
}
- state.invalidationTimer.Reset(rl)
+ state.invalidationJob.Schedule(rl)
ndp.defaultRouters[ip] = state
}
@@ -1009,13 +1009,13 @@ func (ndp *ndpState) rememberOnLinkPrefix(prefix tcpip.Subnet, l time.Duration)
}
state := onLinkPrefixState{
- invalidationTimer: tcpip.NewCancellableTimer(&ndp.nic.mu, func() {
+ invalidationJob: ndp.nic.stack.newJob(&ndp.nic.mu, func() {
ndp.invalidateOnLinkPrefix(prefix)
}),
}
if l < header.NDPInfiniteLifetime {
- state.invalidationTimer.Reset(l)
+ state.invalidationJob.Schedule(l)
}
ndp.onLinkPrefixes[prefix] = state
@@ -1033,7 +1033,7 @@ func (ndp *ndpState) invalidateOnLinkPrefix(prefix tcpip.Subnet) {
return
}
- s.invalidationTimer.StopLocked()
+ s.invalidationJob.Cancel()
delete(ndp.onLinkPrefixes, prefix)
// Let the integrator know a discovered on-link prefix is invalidated.
@@ -1082,14 +1082,14 @@ func (ndp *ndpState) handleOnLinkPrefixInformation(pi header.NDPPrefixInformatio
// This is an already discovered on-link prefix with a
// new non-zero valid lifetime.
//
- // Update the invalidation timer.
+ // Update the invalidation job.
- prefixState.invalidationTimer.StopLocked()
+ prefixState.invalidationJob.Cancel()
if vl < header.NDPInfiniteLifetime {
- // Prefix is valid for a finite lifetime, reset the timer to expire after
+ // Prefix is valid for a finite lifetime, schedule the job to execute after
// the new valid lifetime.
- prefixState.invalidationTimer.Reset(vl)
+ prefixState.invalidationJob.Schedule(vl)
}
ndp.onLinkPrefixes[prefix] = prefixState
@@ -1154,7 +1154,7 @@ func (ndp *ndpState) doSLAAC(prefix tcpip.Subnet, pl, vl time.Duration) {
}
state := slaacPrefixState{
- deprecationTimer: tcpip.NewCancellableTimer(&ndp.nic.mu, func() {
+ deprecationJob: ndp.nic.stack.newJob(&ndp.nic.mu, func() {
state, ok := ndp.slaacPrefixes[prefix]
if !ok {
panic(fmt.Sprintf("ndp: must have a slaacPrefixes entry for the deprecated SLAAC prefix %s", prefix))
@@ -1162,7 +1162,7 @@ func (ndp *ndpState) doSLAAC(prefix tcpip.Subnet, pl, vl time.Duration) {
ndp.deprecateSLAACAddress(state.stableAddr.ref)
}),
- invalidationTimer: tcpip.NewCancellableTimer(&ndp.nic.mu, func() {
+ invalidationJob: ndp.nic.stack.newJob(&ndp.nic.mu, func() {
state, ok := ndp.slaacPrefixes[prefix]
if !ok {
panic(fmt.Sprintf("ndp: must have a slaacPrefixes entry for the invalidated SLAAC prefix %s", prefix))
@@ -1184,19 +1184,19 @@ func (ndp *ndpState) doSLAAC(prefix tcpip.Subnet, pl, vl time.Duration) {
if !ndp.generateSLAACAddr(prefix, &state) {
// We were unable to generate an address for the prefix, we do not nothing
- // further as there is no reason to maintain state or timers for a prefix we
+ // further as there is no reason to maintain state or jobs for a prefix we
// do not have an address for.
return
}
- // Setup the initial timers to deprecate and invalidate prefix.
+ // Setup the initial jobs to deprecate and invalidate prefix.
if pl < header.NDPInfiniteLifetime && pl != 0 {
- state.deprecationTimer.Reset(pl)
+ state.deprecationJob.Schedule(pl)
}
if vl < header.NDPInfiniteLifetime {
- state.invalidationTimer.Reset(vl)
+ state.invalidationJob.Schedule(vl)
state.validUntil = now.Add(vl)
}
@@ -1428,7 +1428,7 @@ func (ndp *ndpState) generateTempSLAACAddr(prefix tcpip.Subnet, prefixState *sla
}
state := tempSLAACAddrState{
- deprecationTimer: tcpip.NewCancellableTimer(&ndp.nic.mu, func() {
+ deprecationJob: ndp.nic.stack.newJob(&ndp.nic.mu, func() {
prefixState, ok := ndp.slaacPrefixes[prefix]
if !ok {
panic(fmt.Sprintf("ndp: must have a slaacPrefixes entry for %s to deprecate temporary address %s", prefix, generatedAddr))
@@ -1441,7 +1441,7 @@ func (ndp *ndpState) generateTempSLAACAddr(prefix tcpip.Subnet, prefixState *sla
ndp.deprecateSLAACAddress(tempAddrState.ref)
}),
- invalidationTimer: tcpip.NewCancellableTimer(&ndp.nic.mu, func() {
+ invalidationJob: ndp.nic.stack.newJob(&ndp.nic.mu, func() {
prefixState, ok := ndp.slaacPrefixes[prefix]
if !ok {
panic(fmt.Sprintf("ndp: must have a slaacPrefixes entry for %s to invalidate temporary address %s", prefix, generatedAddr))
@@ -1454,7 +1454,7 @@ func (ndp *ndpState) generateTempSLAACAddr(prefix tcpip.Subnet, prefixState *sla
ndp.invalidateTempSLAACAddr(prefixState.tempAddrs, generatedAddr.Address, tempAddrState)
}),
- regenTimer: tcpip.NewCancellableTimer(&ndp.nic.mu, func() {
+ regenJob: ndp.nic.stack.newJob(&ndp.nic.mu, func() {
prefixState, ok := ndp.slaacPrefixes[prefix]
if !ok {
panic(fmt.Sprintf("ndp: must have a slaacPrefixes entry for %s to regenerate temporary address after %s", prefix, generatedAddr))
@@ -1481,9 +1481,9 @@ func (ndp *ndpState) generateTempSLAACAddr(prefix tcpip.Subnet, prefixState *sla
ref: ref,
}
- state.deprecationTimer.Reset(pl)
- state.invalidationTimer.Reset(vl)
- state.regenTimer.Reset(pl - ndp.configs.RegenAdvanceDuration)
+ state.deprecationJob.Schedule(pl)
+ state.invalidationJob.Schedule(vl)
+ state.regenJob.Schedule(pl - ndp.configs.RegenAdvanceDuration)
prefixState.generationAttempts++
prefixState.tempAddrs[generatedAddr.Address] = state
@@ -1518,16 +1518,16 @@ func (ndp *ndpState) refreshSLAACPrefixLifetimes(prefix tcpip.Subnet, prefixStat
prefixState.stableAddr.ref.deprecated = false
}
- // If prefix was preferred for some finite lifetime before, stop the
- // deprecation timer so it can be reset.
- prefixState.deprecationTimer.StopLocked()
+ // If prefix was preferred for some finite lifetime before, cancel the
+ // deprecation job so it can be reset.
+ prefixState.deprecationJob.Cancel()
now := time.Now()
- // Reset the deprecation timer if prefix has a finite preferred lifetime.
+ // Schedule the deprecation job if prefix has a finite preferred lifetime.
if pl < header.NDPInfiniteLifetime {
if !deprecated {
- prefixState.deprecationTimer.Reset(pl)
+ prefixState.deprecationJob.Schedule(pl)
}
prefixState.preferredUntil = now.Add(pl)
} else {
@@ -1546,9 +1546,9 @@ func (ndp *ndpState) refreshSLAACPrefixLifetimes(prefix tcpip.Subnet, prefixStat
// 3) Otherwise, reset the valid lifetime of the prefix to 2 hours.
if vl >= header.NDPInfiniteLifetime {
- // Handle the infinite valid lifetime separately as we do not keep a timer
- // in this case.
- prefixState.invalidationTimer.StopLocked()
+ // Handle the infinite valid lifetime separately as we do not schedule a
+ // job in this case.
+ prefixState.invalidationJob.Cancel()
prefixState.validUntil = time.Time{}
} else {
var effectiveVl time.Duration
@@ -1569,8 +1569,8 @@ func (ndp *ndpState) refreshSLAACPrefixLifetimes(prefix tcpip.Subnet, prefixStat
}
if effectiveVl != 0 {
- prefixState.invalidationTimer.StopLocked()
- prefixState.invalidationTimer.Reset(effectiveVl)
+ prefixState.invalidationJob.Cancel()
+ prefixState.invalidationJob.Schedule(effectiveVl)
prefixState.validUntil = now.Add(effectiveVl)
}
}
@@ -1582,7 +1582,7 @@ func (ndp *ndpState) refreshSLAACPrefixLifetimes(prefix tcpip.Subnet, prefixStat
}
// Note, we do not need to update the entries in the temporary address map
- // after updating the timers because the timers are held as pointers.
+ // after updating the jobs because the jobs are held as pointers.
var regenForAddr tcpip.Address
allAddressesRegenerated := true
for tempAddr, tempAddrState := range prefixState.tempAddrs {
@@ -1596,14 +1596,14 @@ func (ndp *ndpState) refreshSLAACPrefixLifetimes(prefix tcpip.Subnet, prefixStat
}
// If the address is no longer valid, invalidate it immediately. Otherwise,
- // reset the invalidation timer.
+ // reset the invalidation job.
newValidLifetime := validUntil.Sub(now)
if newValidLifetime <= 0 {
ndp.invalidateTempSLAACAddr(prefixState.tempAddrs, tempAddr, tempAddrState)
continue
}
- tempAddrState.invalidationTimer.StopLocked()
- tempAddrState.invalidationTimer.Reset(newValidLifetime)
+ tempAddrState.invalidationJob.Cancel()
+ tempAddrState.invalidationJob.Schedule(newValidLifetime)
// As per RFC 4941 section 3.3 step 4, the preferred lifetime of a temporary
// address is the lower of the preferred lifetime of the stable address or
@@ -1616,17 +1616,17 @@ func (ndp *ndpState) refreshSLAACPrefixLifetimes(prefix tcpip.Subnet, prefixStat
}
// If the address is no longer preferred, deprecate it immediately.
- // Otherwise, reset the deprecation timer.
+ // Otherwise, schedule the deprecation job again.
newPreferredLifetime := preferredUntil.Sub(now)
- tempAddrState.deprecationTimer.StopLocked()
+ tempAddrState.deprecationJob.Cancel()
if newPreferredLifetime <= 0 {
ndp.deprecateSLAACAddress(tempAddrState.ref)
} else {
tempAddrState.ref.deprecated = false
- tempAddrState.deprecationTimer.Reset(newPreferredLifetime)
+ tempAddrState.deprecationJob.Schedule(newPreferredLifetime)
}
- tempAddrState.regenTimer.StopLocked()
+ tempAddrState.regenJob.Cancel()
if tempAddrState.regenerated {
} else {
allAddressesRegenerated = false
@@ -1637,7 +1637,7 @@ func (ndp *ndpState) refreshSLAACPrefixLifetimes(prefix tcpip.Subnet, prefixStat
// immediately after we finish iterating over the temporary addresses.
regenForAddr = tempAddr
} else {
- tempAddrState.regenTimer.Reset(newPreferredLifetime - ndp.configs.RegenAdvanceDuration)
+ tempAddrState.regenJob.Schedule(newPreferredLifetime - ndp.configs.RegenAdvanceDuration)
}
}
}
@@ -1717,7 +1717,7 @@ func (ndp *ndpState) cleanupSLAACAddrResourcesAndNotify(addr tcpip.AddressWithPr
ndp.cleanupSLAACPrefixResources(prefix, state)
}
-// cleanupSLAACPrefixResources cleansup a SLAAC prefix's timers and entry.
+// cleanupSLAACPrefixResources cleans up a SLAAC prefix's jobs and entry.
//
// Panics if the SLAAC prefix is not known.
//
@@ -1729,8 +1729,8 @@ func (ndp *ndpState) cleanupSLAACPrefixResources(prefix tcpip.Subnet, state slaa
}
state.stableAddr.ref = nil
- state.deprecationTimer.StopLocked()
- state.invalidationTimer.StopLocked()
+ state.deprecationJob.Cancel()
+ state.invalidationJob.Cancel()
delete(ndp.slaacPrefixes, prefix)
}
@@ -1775,13 +1775,13 @@ func (ndp *ndpState) cleanupTempSLAACAddrResourcesAndNotify(addr tcpip.AddressWi
}
// cleanupTempSLAACAddrResourcesAndNotify cleans up a temporary SLAAC address's
-// timers and entry.
+// jobs and entry.
//
// The NIC that ndp belongs to MUST be locked.
func (ndp *ndpState) cleanupTempSLAACAddrResources(tempAddrs map[tcpip.Address]tempSLAACAddrState, tempAddr tcpip.Address, tempAddrState tempSLAACAddrState) {
- tempAddrState.deprecationTimer.StopLocked()
- tempAddrState.invalidationTimer.StopLocked()
- tempAddrState.regenTimer.StopLocked()
+ tempAddrState.deprecationJob.Cancel()
+ tempAddrState.invalidationJob.Cancel()
+ tempAddrState.regenJob.Cancel()
delete(tempAddrs, tempAddr)
}
@@ -1860,7 +1860,7 @@ func (ndp *ndpState) startSolicitingRouters() {
var done bool
ndp.rtrSolicit.done = &done
- ndp.rtrSolicit.timer = time.AfterFunc(delay, func() {
+ ndp.rtrSolicit.timer = ndp.nic.stack.Clock().AfterFunc(delay, func() {
ndp.nic.mu.Lock()
if done {
// If we reach this point, it means that the RS timer fired after another
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 2b7ece851..a6faa22c2 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -728,6 +728,11 @@ func New(opts Options) *Stack {
return s
}
+// newJob returns a tcpip.Job using the Stack clock.
+func (s *Stack) newJob(l sync.Locker, f func()) *tcpip.Job {
+ return tcpip.NewJob(s.clock, l, f)
+}
+
// UniqueID returns a unique identifier.
func (s *Stack) UniqueID() uint64 {
return s.uniqueIDGenerator.UniqueID()
@@ -801,9 +806,10 @@ func (s *Stack) SetTransportProtocolHandler(p tcpip.TransportProtocolNumber, h f
}
}
-// NowNanoseconds implements tcpip.Clock.NowNanoseconds.
-func (s *Stack) NowNanoseconds() int64 {
- return s.clock.NowNanoseconds()
+// Clock returns the Stack's clock for retrieving the current time and
+// scheduling work.
+func (s *Stack) Clock() tcpip.Clock {
+ return s.clock
}
// Stats returns a mutable copy of the current stats.
diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go
index ff14a3b3c..21aafb0a2 100644
--- a/pkg/tcpip/tcpip.go
+++ b/pkg/tcpip/tcpip.go
@@ -192,7 +192,7 @@ func (e ErrSaveRejection) Error() string {
return "save rejected due to unsupported networking state: " + e.Err.Error()
}
-// A Clock provides the current time.
+// A Clock provides the current time and schedules work for execution.
//
// Times returned by a Clock should always be used for application-visible
// time. Only monotonic times should be used for netstack internal timekeeping.
@@ -203,6 +203,31 @@ type Clock interface {
// NowMonotonic returns a monotonic time value.
NowMonotonic() int64
+
+ // AfterFunc waits for the duration to elapse and then calls f in its own
+ // goroutine. It returns a Timer that can be used to cancel the call using
+ // its Stop method.
+ AfterFunc(d time.Duration, f func()) Timer
+}
+
+// Timer represents a single event. A Timer must be created with
+// Clock.AfterFunc.
+type Timer interface {
+ // Stop prevents the Timer from firing. It returns true if the call stops the
+ // timer, false if the timer has already expired or been stopped.
+ //
+ // If Stop returns false, then the timer has already expired and the function
+ // f of Clock.AfterFunc(d, f) has been started in its own goroutine; Stop
+ // does not wait for f to complete before returning. If the caller needs to
+ // know whether f is completed, it must coordinate with f explicitly.
+ Stop() bool
+
+ // Reset changes the timer to expire after duration d.
+ //
+ // Reset should be invoked only on stopped or expired timers. If the timer is
+ // known to have expired, Reset can be used directly. Otherwise, the caller
+ // must coordinate with the function f of Clock.AfterFunc(d, f).
+ Reset(d time.Duration)
}
// Address is a byte slice cast as a string that represents the address of a
diff --git a/pkg/tcpip/time_unsafe.go b/pkg/tcpip/time_unsafe.go
index 7f172f978..f32d58091 100644
--- a/pkg/tcpip/time_unsafe.go
+++ b/pkg/tcpip/time_unsafe.go
@@ -20,7 +20,7 @@
package tcpip
import (
- _ "time" // Used with go:linkname.
+ "time" // Used with go:linkname.
_ "unsafe" // Required for go:linkname.
)
@@ -45,3 +45,31 @@ func (*StdClock) NowMonotonic() int64 {
_, _, mono := now()
return mono
}
+
+// AfterFunc implements Clock.AfterFunc.
+func (*StdClock) AfterFunc(d time.Duration, f func()) Timer {
+ return &stdTimer{
+ t: time.AfterFunc(d, f),
+ }
+}
+
+type stdTimer struct {
+ t *time.Timer
+}
+
+var _ Timer = (*stdTimer)(nil)
+
+// Stop implements Timer.Stop.
+func (st *stdTimer) Stop() bool {
+ return st.t.Stop()
+}
+
+// Reset implements Timer.Reset.
+func (st *stdTimer) Reset(d time.Duration) {
+ st.t.Reset(d)
+}
+
+// NewStdTimer returns a Timer implemented with the time package.
+func NewStdTimer(t *time.Timer) Timer {
+ return &stdTimer{t: t}
+}
diff --git a/pkg/tcpip/timer.go b/pkg/tcpip/timer.go
index 5554c573f..f1dd7c310 100644
--- a/pkg/tcpip/timer.go
+++ b/pkg/tcpip/timer.go
@@ -20,50 +20,49 @@ import (
"gvisor.dev/gvisor/pkg/sync"
)
-// cancellableTimerInstance is a specific instance of CancellableTimer.
+// jobInstance is a specific instance of Job.
//
-// Different instances are created each time CancellableTimer is Reset so each
-// timer has its own earlyReturn signal. This is to address a bug when a
-// CancellableTimer is stopped and reset in quick succession resulting in a
-// timer instance's earlyReturn signal being affected or seen by another timer
-// instance.
+// Different instances are created each time Job is scheduled so each timer has
+// its own earlyReturn signal. This is to address a bug when a Job is stopped
+// and reset in quick succession resulting in a timer instance's earlyReturn
+// signal being affected or seen by another timer instance.
//
// Consider the following sceneario where timer instances share a common
// earlyReturn signal (T1 creates, stops and resets a Cancellable timer under a
// lock L; T2, T3, T4 and T5 are goroutines that handle the first (A), second
// (B), third (C), and fourth (D) instance of the timer firing, respectively):
// T1: Obtain L
-// T1: Create a new CancellableTimer w/ lock L (create instance A)
+// T1: Create a new Job w/ lock L (create instance A)
// T2: instance A fires, blocked trying to obtain L.
// T1: Attempt to stop instance A (set earlyReturn = true)
-// T1: Reset timer (create instance B)
+// T1: Schedule timer (create instance B)
// T3: instance B fires, blocked trying to obtain L.
// T1: Attempt to stop instance B (set earlyReturn = true)
-// T1: Reset timer (create instance C)
+// T1: Schedule timer (create instance C)
// T4: instance C fires, blocked trying to obtain L.
// T1: Attempt to stop instance C (set earlyReturn = true)
-// T1: Reset timer (create instance D)
+// T1: Schedule timer (create instance D)
// T5: instance D fires, blocked trying to obtain L.
// T1: Release L
//
-// Now that T1 has released L, any of the 4 timer instances can take L and check
-// earlyReturn. If the timers simply check earlyReturn and then do nothing
-// further, then instance D will never early return even though it was not
-// requested to stop. If the timers reset earlyReturn before early returning,
-// then all but one of the timers will do work when only one was expected to.
-// If CancellableTimer resets earlyReturn when resetting, then all the timers
+// Now that T1 has released L, any of the 4 timer instances can take L and
+// check earlyReturn. If the timers simply check earlyReturn and then do
+// nothing further, then instance D will never early return even though it was
+// not requested to stop. If the timers reset earlyReturn before early
+// returning, then all but one of the timers will do work when only one was
+// expected to. If Job resets earlyReturn when resetting, then all the timers
// will fire (again, when only one was expected to).
//
// To address the above concerns the simplest solution was to give each timer
// its own earlyReturn signal.
-type cancellableTimerInstance struct {
- timer *time.Timer
+type jobInstance struct {
+ timer Timer
// Used to inform the timer to early return when it gets stopped while the
// lock the timer tries to obtain when fired is held (T1 is a goroutine that
// tries to cancel the timer and T2 is the goroutine that handles the timer
// firing):
- // T1: Obtain the lock, then call StopLocked()
+ // T1: Obtain the lock, then call Cancel()
// T2: timer fires, and gets blocked on obtaining the lock
// T1: Releases lock
// T2: Obtains lock does unintended work
@@ -74,29 +73,33 @@ type cancellableTimerInstance struct {
earlyReturn *bool
}
-// stop stops the timer instance t from firing if it hasn't fired already. If it
+// stop stops the job instance j from firing if it hasn't fired already. If it
// has fired and is blocked at obtaining the lock, earlyReturn will be set to
// true so that it will early return when it obtains the lock.
-func (t *cancellableTimerInstance) stop() {
- if t.timer != nil {
- t.timer.Stop()
- *t.earlyReturn = true
+func (j *jobInstance) stop() {
+ if j.timer != nil {
+ j.timer.Stop()
+ *j.earlyReturn = true
}
}
-// CancellableTimer is a timer that does some work and can be safely cancelled
-// when it fires at the same time some "related work" is being done.
+// Job represents some work that can be scheduled for execution. The work can
+// be safely cancelled when it fires at the same time some "related work" is
+// being done.
//
// The term "related work" is defined as some work that needs to be done while
// holding some lock that the timer must also hold while doing some work.
//
-// Note, it is not safe to copy a CancellableTimer as its timer instance creates
-// a closure over the address of the CancellableTimer.
-type CancellableTimer struct {
+// Note, it is not safe to copy a Job as its timer instance creates
+// a closure over the address of the Job.
+type Job struct {
_ sync.NoCopy
+ // The clock used to schedule the backing timer
+ clock Clock
+
// The active instance of a cancellable timer.
- instance cancellableTimerInstance
+ instance jobInstance
// locker is the lock taken by the timer immediately after it fires and must
// be held when attempting to stop the timer.
@@ -113,59 +116,91 @@ type CancellableTimer struct {
fn func()
}
-// StopLocked prevents the Timer from firing if it has not fired already.
+// Cancel prevents the Job from executing if it has not executed already.
//
-// If the timer is blocked on obtaining the t.locker lock when StopLocked is
-// called, it will early return instead of calling t.fn.
+// Cancel requires appropriate locking to be in place for any resources managed
+// by the Job. If the Job is blocked on obtaining the lock when Cancel is
+// called, it will early return.
//
// Note, t will be modified.
//
-// t.locker MUST be locked.
-func (t *CancellableTimer) StopLocked() {
- t.instance.stop()
+// j.locker MUST be locked.
+func (j *Job) Cancel() {
+ j.instance.stop()
// Nothing to do with the stopped instance anymore.
- t.instance = cancellableTimerInstance{}
+ j.instance = jobInstance{}
}
-// Reset changes the timer to expire after duration d.
+// Schedule schedules the Job for execution after duration d. This can be
+// called on cancelled or completed Jobs to schedule them again.
//
-// Note, t will be modified.
+// Schedule should be invoked only on unscheduled, cancelled, or completed
+// Jobs. To be safe, callers should always call Cancel before calling Schedule.
//
-// Reset should only be called on stopped or expired timers. To be safe, callers
-// should always call StopLocked before calling Reset.
-func (t *CancellableTimer) Reset(d time.Duration) {
+// Note, j will be modified.
+func (j *Job) Schedule(d time.Duration) {
// Create a new instance.
earlyReturn := false
// Capture the locker so that updating the timer does not cause a data race
// when a timer fires and tries to obtain the lock (read the timer's locker).
- locker := t.locker
- t.instance = cancellableTimerInstance{
- timer: time.AfterFunc(d, func() {
+ locker := j.locker
+ j.instance = jobInstance{
+ timer: j.clock.AfterFunc(d, func() {
locker.Lock()
defer locker.Unlock()
if earlyReturn {
// If we reach this point, it means that the timer fired while another
- // goroutine called StopLocked while it had the lock. Simply return
- // here and do nothing further.
+ // goroutine called Cancel while it had the lock. Simply return here
+ // and do nothing further.
earlyReturn = false
return
}
- t.fn()
+ j.fn()
}),
earlyReturn: &earlyReturn,
}
}
-// NewCancellableTimer returns an unscheduled CancellableTimer with the given
-// locker and fn.
-//
-// fn MUST NOT attempt to lock locker.
-//
-// Callers must call Reset to schedule the timer to fire.
-func NewCancellableTimer(locker sync.Locker, fn func()) *CancellableTimer {
- return &CancellableTimer{locker: locker, fn: fn}
+// NewJob returns a new Job that can be used to schedule f to run in its own
+// gorountine. l will be locked before calling f then unlocked after f returns.
+//
+// var clock tcpip.StdClock
+// var mu sync.Mutex
+// message := "foo"
+// job := tcpip.NewJob(&clock, &mu, func() {
+// fmt.Println(message)
+// })
+// job.Schedule(time.Second)
+//
+// mu.Lock()
+// message = "bar"
+// mu.Unlock()
+//
+// // Output: bar
+//
+// f MUST NOT attempt to lock l.
+//
+// l MUST be locked prior to calling the returned job's Cancel().
+//
+// var clock tcpip.StdClock
+// var mu sync.Mutex
+// message := "foo"
+// job := tcpip.NewJob(&clock, &mu, func() {
+// fmt.Println(message)
+// })
+// job.Schedule(time.Second)
+//
+// mu.Lock()
+// job.Cancel()
+// mu.Unlock()
+func NewJob(c Clock, l sync.Locker, f func()) *Job {
+ return &Job{
+ clock: c,
+ locker: l,
+ fn: f,
+ }
}
diff --git a/pkg/tcpip/transport/icmp/endpoint.go b/pkg/tcpip/transport/icmp/endpoint.go
index 678f4e016..4612be4e7 100644
--- a/pkg/tcpip/transport/icmp/endpoint.go
+++ b/pkg/tcpip/transport/icmp/endpoint.go
@@ -797,7 +797,7 @@ func (e *endpoint) HandlePacket(r *stack.Route, id stack.TransportEndpointID, pk
e.rcvList.PushBack(packet)
e.rcvBufSize += packet.data.Size()
- packet.timestamp = e.stack.NowNanoseconds()
+ packet.timestamp = e.stack.Clock().NowNanoseconds()
e.rcvMu.Unlock()
e.stats.PacketsReceived.Increment()
diff --git a/pkg/tcpip/transport/packet/endpoint.go b/pkg/tcpip/transport/packet/endpoint.go
index 8f167391f..0e46e6355 100644
--- a/pkg/tcpip/transport/packet/endpoint.go
+++ b/pkg/tcpip/transport/packet/endpoint.go
@@ -499,7 +499,7 @@ func (ep *endpoint) HandlePacket(nicID tcpip.NICID, localAddr tcpip.LinkAddress,
combinedVV.Append(pkt.Data)
packet.data = combinedVV
}
- packet.timestampNS = ep.stack.NowNanoseconds()
+ packet.timestampNS = ep.stack.Clock().NowNanoseconds()
ep.rcvList.PushBack(&packet)
ep.rcvBufSize += packet.data.Size()
diff --git a/pkg/tcpip/transport/raw/endpoint.go b/pkg/tcpip/transport/raw/endpoint.go
index aefe0e2b2..f85a68554 100644
--- a/pkg/tcpip/transport/raw/endpoint.go
+++ b/pkg/tcpip/transport/raw/endpoint.go
@@ -700,7 +700,7 @@ func (e *endpoint) HandlePacket(route *stack.Route, pkt *stack.PacketBuffer) {
}
combinedVV.Append(pkt.Data)
packet.data = combinedVV
- packet.timestampNS = e.stack.NowNanoseconds()
+ packet.timestampNS = e.stack.Clock().NowNanoseconds()
e.rcvList.PushBack(packet)
e.rcvBufSize += packet.data.Size()
diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go
index a14643ae8..6e692da07 100644
--- a/pkg/tcpip/transport/udp/endpoint.go
+++ b/pkg/tcpip/transport/udp/endpoint.go
@@ -1451,7 +1451,7 @@ func (e *endpoint) HandlePacket(r *stack.Route, id stack.TransportEndpointID, pk
packet.tos, _ = header.IPv6(pkt.NetworkHeader).TOS()
}
- packet.timestamp = e.stack.NowNanoseconds()
+ packet.timestamp = e.stack.Clock().NowNanoseconds()
e.rcvMu.Unlock()
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-30 01:29:22 +0000