Merge release-20200323.0-201-g8b72623 (automated)

6 files changed, 104 insertions, 59 deletions

diff --git a/pkg/metric/metric.go b/pkg/metric/metric.go
index 895253625..64aa365ce 100644
--- a/pkg/metric/metric.go
+++ b/pkg/metric/metric.go
@@ -39,16 +39,11 @@ var (
 // Uint64Metric encapsulates a uint64 that represents some kind of metric to be
 // monitored.
 //
-// All metrics must be cumulative, meaning that their values will only increase
-// over time.
-//
 // Metrics are not saved across save/restore and thus reset to zero on restore.
 //
-// TODO(b/67298402): Support non-cumulative metrics.
 // TODO(b/67298427): Support metric fields.
 type Uint64Metric struct {
-	// value is the actual value of the metric. It must be accessed
-	// atomically.
+	// value is the actual value of the metric. It must be accessed atomically.
 	value uint64
 }
 
@@ -110,13 +105,10 @@ type customUint64Metric struct {
 // Register must only be called at init and will return and error if called
 // after Initialized.
 //
-// All metrics must be cumulative, meaning that the return values of value must
-// only increase over time.
-//
 // Preconditions:
 //  * name must be globally unique.
 //  * Initialize/Disable have not been called.
-func RegisterCustomUint64Metric(name string, sync bool, description string, value func() uint64) error {
+func RegisterCustomUint64Metric(name string, cumulative, sync bool, units pb.MetricMetadata_Units, description string, value func() uint64) error {
 	if initialized {
 		return ErrInitializationDone
 	}
@@ -129,9 +121,10 @@ func RegisterCustomUint64Metric(name string, sync bool, description string, valu
 		metadata: &pb.MetricMetadata{
 			Name:        name,
 			Description: description,
-			Cumulative:  true,
+			Cumulative:  cumulative,
 			Sync:        sync,
-			Type:        pb.MetricMetadata_UINT64,
+			Type:        pb.MetricMetadata_TYPE_UINT64,
+			Units:       units,
 		},
 		value: value,
 	}
@@ -140,24 +133,32 @@ func RegisterCustomUint64Metric(name string, sync bool, description string, valu
 
 // MustRegisterCustomUint64Metric calls RegisterCustomUint64Metric and panics
 // if it returns an error.
-func MustRegisterCustomUint64Metric(name string, sync bool, description string, value func() uint64) {
-	if err := RegisterCustomUint64Metric(name, sync, description, value); err != nil {
+func MustRegisterCustomUint64Metric(name string, cumulative, sync bool, description string, value func() uint64) {
+	if err := RegisterCustomUint64Metric(name, cumulative, sync, pb.MetricMetadata_UNITS_NONE, description, value); err != nil {
 		panic(fmt.Sprintf("Unable to register metric %q: %v", name, err))
 	}
 }
 
-// NewUint64Metric creates and registers a new metric with the given name.
+// NewUint64Metric creates and registers a new cumulative metric with the given name.
 //
 // Metrics must be statically defined (i.e., at init).
-func NewUint64Metric(name string, sync bool, description string) (*Uint64Metric, error) {
+func NewUint64Metric(name string, sync bool, units pb.MetricMetadata_Units, description string) (*Uint64Metric, error) {
 	var m Uint64Metric
-	return &m, RegisterCustomUint64Metric(name, sync, description, m.Value)
+	return &m, RegisterCustomUint64Metric(name, true /* cumulative */, sync, units, description, m.Value)
 }
 
-// MustCreateNewUint64Metric calls NewUint64Metric and panics if it returns an
-// error.
+// MustCreateNewUint64Metric calls NewUint64Metric and panics if it returns an error.
 func MustCreateNewUint64Metric(name string, sync bool, description string) *Uint64Metric {
-	m, err := NewUint64Metric(name, sync, description)
+	m, err := NewUint64Metric(name, sync, pb.MetricMetadata_UNITS_NONE, description)
+	if err != nil {
+		panic(fmt.Sprintf("Unable to create metric %q: %v", name, err))
+	}
+	return m
+}
+
+// MustCreateNewUint64NanosecondsMetric calls NewUint64Metric and panics if it returns an error.
+func MustCreateNewUint64NanosecondsMetric(name string, sync bool, description string) *Uint64Metric {
+	m, err := NewUint64Metric(name, sync, pb.MetricMetadata_UNITS_NANOSECONDS, description)
 	if err != nil {
 		panic(fmt.Sprintf("Unable to create metric %q: %v", name, err))
 	}
diff --git a/pkg/metric/metric_go_proto/metric.pb.go b/pkg/metric/metric_go_proto/metric.pb.go
index 553236535..13f41a80d 100755
--- a/pkg/metric/metric_go_proto/metric.pb.go
+++ b/pkg/metric/metric_go_proto/metric.pb.go
@@ -23,15 +23,15 @@ const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package
 type MetricMetadata_Type int32
 
 const (
-	MetricMetadata_UINT64 MetricMetadata_Type = 0
+	MetricMetadata_TYPE_UINT64 MetricMetadata_Type = 0
 )
 
 var MetricMetadata_Type_name = map[int32]string{
-	0: "UINT64",
+	0: "TYPE_UINT64",
 }
 
 var MetricMetadata_Type_value = map[string]int32{
-	"UINT64": 0,
+	"TYPE_UINT64": 0,
 }
 
 func (x MetricMetadata_Type) String() string {
@@ -42,15 +42,41 @@ func (MetricMetadata_Type) EnumDescriptor() ([]byte, []int) {
 	return fileDescriptor_87b8778a4ff2ab5c, []int{0, 0}
 }
 
+type MetricMetadata_Units int32
+
+const (
+	MetricMetadata_UNITS_NONE        MetricMetadata_Units = 0
+	MetricMetadata_UNITS_NANOSECONDS MetricMetadata_Units = 1
+)
+
+var MetricMetadata_Units_name = map[int32]string{
+	0: "UNITS_NONE",
+	1: "UNITS_NANOSECONDS",
+}
+
+var MetricMetadata_Units_value = map[string]int32{
+	"UNITS_NONE":        0,
+	"UNITS_NANOSECONDS": 1,
+}
+
+func (x MetricMetadata_Units) String() string {
+	return proto.EnumName(MetricMetadata_Units_name, int32(x))
+}
+
+func (MetricMetadata_Units) EnumDescriptor() ([]byte, []int) {
+	return fileDescriptor_87b8778a4ff2ab5c, []int{0, 1}
+}
+
 type MetricMetadata struct {
-	Name                 string              `protobuf:"bytes,1,opt,name=name,proto3" json:"name,omitempty"`
-	Description          string              `protobuf:"bytes,2,opt,name=description,proto3" json:"description,omitempty"`
-	Cumulative           bool                `protobuf:"varint,3,opt,name=cumulative,proto3" json:"cumulative,omitempty"`
-	Sync                 bool                `protobuf:"varint,4,opt,name=sync,proto3" json:"sync,omitempty"`
-	Type                 MetricMetadata_Type `protobuf:"varint,5,opt,name=type,proto3,enum=gvisor.MetricMetadata_Type" json:"type,omitempty"`
-	XXX_NoUnkeyedLiteral struct{}            `json:"-"`
-	XXX_unrecognized     []byte              `json:"-"`
-	XXX_sizecache        int32               `json:"-"`
+	Name                 string               `protobuf:"bytes,1,opt,name=name,proto3" json:"name,omitempty"`
+	Description          string               `protobuf:"bytes,2,opt,name=description,proto3" json:"description,omitempty"`
+	Cumulative           bool                 `protobuf:"varint,3,opt,name=cumulative,proto3" json:"cumulative,omitempty"`
+	Sync                 bool                 `protobuf:"varint,4,opt,name=sync,proto3" json:"sync,omitempty"`
+	Type                 MetricMetadata_Type  `protobuf:"varint,5,opt,name=type,proto3,enum=gvisor.MetricMetadata_Type" json:"type,omitempty"`
+	Units                MetricMetadata_Units `protobuf:"varint,6,opt,name=units,proto3,enum=gvisor.MetricMetadata_Units" json:"units,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}             `json:"-"`
+	XXX_unrecognized     []byte               `json:"-"`
+	XXX_sizecache        int32                `json:"-"`
 }
 
 func (m *MetricMetadata) Reset()         { *m = MetricMetadata{} }
@@ -110,7 +136,14 @@ func (m *MetricMetadata) GetType() MetricMetadata_Type {
 	if m != nil {
 		return m.Type
 	}
-	return MetricMetadata_UINT64
+	return MetricMetadata_TYPE_UINT64
+}
+
+func (m *MetricMetadata) GetUnits() MetricMetadata_Units {
+	if m != nil {
+		return m.Units
+	}
+	return MetricMetadata_UNITS_NONE
 }
 
 type MetricRegistration struct {
@@ -266,6 +299,7 @@ func (m *MetricUpdate) GetMetrics() []*MetricValue {
 
 func init() {
 	proto.RegisterEnum("gvisor.MetricMetadata_Type", MetricMetadata_Type_name, MetricMetadata_Type_value)
+	proto.RegisterEnum("gvisor.MetricMetadata_Units", MetricMetadata_Units_name, MetricMetadata_Units_value)
 	proto.RegisterType((*MetricMetadata)(nil), "gvisor.MetricMetadata")
 	proto.RegisterType((*MetricRegistration)(nil), "gvisor.MetricRegistration")
 	proto.RegisterType((*MetricValue)(nil), "gvisor.MetricValue")
@@ -275,23 +309,27 @@ func init() {
 func init() { proto.RegisterFile("pkg/metric/metric.proto", fileDescriptor_87b8778a4ff2ab5c) }
 
 var fileDescriptor_87b8778a4ff2ab5c = []byte{
-	// 288 bytes of a gzipped FileDescriptorProto
-	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x6c, 0x91, 0xc1, 0x4b, 0xc3, 0x30,
-	0x14, 0xc6, 0x17, 0xd7, 0x75, 0xfa, 0x3a, 0x86, 0x44, 0xd0, 0x80, 0x20, 0xa5, 0x5e, 0x7a, 0xb1,
-	0x93, 0x39, 0x76, 0xf3, 0xe2, 0x41, 0xf4, 0x30, 0x85, 0xb0, 0x79, 0x95, 0xd8, 0x86, 0x12, 0x5c,
-	0xdb, 0xd0, 0xa4, 0x85, 0xfe, 0x75, 0xfe, 0x6b, 0xd2, 0x17, 0x95, 0x4d, 0x76, 0xca, 0xcb, 0xfb,
-	0xde, 0xf7, 0xf1, 0xcb, 0x0b, 0x5c, 0xe8, 0xcf, 0x7c, 0x56, 0x48, 0x5b, 0xab, 0xf4, 0xe7, 0x48,
-	0x74, 0x5d, 0xd9, 0x8a, 0xfa, 0x79, 0xab, 0x4c, 0x55, 0x47, 0x5f, 0x04, 0xa6, 0x2b, 0x14, 0x56,
-	0xd2, 0x8a, 0x4c, 0x58, 0x41, 0x29, 0x78, 0xa5, 0x28, 0x24, 0x23, 0x21, 0x89, 0x4f, 0x38, 0xd6,
-	0x34, 0x84, 0x20, 0x93, 0x26, 0xad, 0x95, 0xb6, 0xaa, 0x2a, 0xd9, 0x11, 0x4a, 0xbb, 0x2d, 0x7a,
-	0x05, 0x90, 0x36, 0x45, 0xb3, 0x15, 0x56, 0xb5, 0x92, 0x0d, 0x43, 0x12, 0x1f, 0xf3, 0x9d, 0x4e,
-	0x9f, 0x6a, 0xba, 0x32, 0x65, 0x1e, 0x2a, 0x58, 0xd3, 0x19, 0x78, 0xb6, 0xd3, 0x92, 0x8d, 0x42,
-	0x12, 0x4f, 0xe7, 0x97, 0x89, 0x63, 0x4a, 0xf6, 0x79, 0x92, 0x75, 0xa7, 0x25, 0xc7, 0xc1, 0x88,
-	0x82, 0xd7, 0xdf, 0x28, 0x80, 0xbf, 0x79, 0x7e, 0x59, 0x2f, 0x17, 0xa7, 0x83, 0xe8, 0x11, 0xa8,
-	0x33, 0x70, 0x99, 0x2b, 0x63, 0x6b, 0x81, 0x38, 0xb7, 0x30, 0x76, 0xef, 0x35, 0x8c, 0x84, 0xc3,
-	0x38, 0x98, 0x9f, 0x1f, 0x4e, 0xe7, 0xbf, 0x63, 0xd1, 0x2b, 0x04, 0x4e, 0x7a, 0x13, 0xdb, 0x46,
-	0x1e, 0xdc, 0xc2, 0x35, 0x4c, 0x1a, 0x55, 0xda, 0xe5, 0xe2, 0xbd, 0xed, 0x67, 0x70, 0x0d, 0xde,
-	0xd3, 0x80, 0x07, 0xae, 0x8b, 0xc6, 0x87, 0x31, 0x8c, 0x50, 0x8d, 0xee, 0x61, 0xe2, 0x02, 0x37,
-	0x3a, 0x13, 0x56, 0xd2, 0x9b, 0xff, 0x48, 0x67, 0xfb, 0x48, 0x68, 0xff, 0xe3, 0xf9, 0xf0, 0xf1,
-	0xa3, 0xee, 0xbe, 0x03, 0x00, 0x00, 0xff, 0xff, 0xcb, 0x7f, 0xcb, 0x46, 0xc3, 0x01, 0x00, 0x00,
+	// 349 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x74, 0x92, 0x4f, 0x4f, 0xc2, 0x40,
+	0x10, 0xc5, 0x29, 0xb4, 0xa0, 0x53, 0x82, 0xb8, 0x46, 0x69, 0xa2, 0x31, 0x4d, 0xbd, 0xf4, 0x62,
+	0x31, 0x48, 0xb8, 0x79, 0xf0, 0x0f, 0x46, 0x0e, 0xb4, 0xa6, 0xb4, 0x26, 0x9e, 0xc8, 0x5a, 0x36,
+	0x64, 0x23, 0xb4, 0x4d, 0xbb, 0x25, 0xe1, 0x1b, 0xf9, 0x31, 0x4d, 0x67, 0xd1, 0x80, 0xc1, 0x53,
+	0xa7, 0xf3, 0xde, 0x9b, 0xfd, 0xed, 0x64, 0xa1, 0x93, 0x7e, 0xce, 0xbb, 0x4b, 0x26, 0x32, 0x1e,
+	0x6d, 0x3e, 0x4e, 0x9a, 0x25, 0x22, 0x21, 0xf5, 0xf9, 0x8a, 0xe7, 0x49, 0x66, 0x7d, 0x55, 0xa1,
+	0x35, 0x46, 0x61, 0xcc, 0x04, 0x9d, 0x51, 0x41, 0x09, 0x01, 0x35, 0xa6, 0x4b, 0x66, 0x28, 0xa6,
+	0x62, 0x1f, 0xfa, 0x58, 0x13, 0x13, 0xf4, 0x19, 0xcb, 0xa3, 0x8c, 0xa7, 0x82, 0x27, 0xb1, 0x51,
+	0x45, 0x69, 0xbb, 0x45, 0x2e, 0x01, 0xa2, 0x62, 0x59, 0x2c, 0xa8, 0xe0, 0x2b, 0x66, 0xd4, 0x4c,
+	0xc5, 0x3e, 0xf0, 0xb7, 0x3a, 0xe5, 0xd4, 0x7c, 0x1d, 0x47, 0x86, 0x8a, 0x0a, 0xd6, 0xa4, 0x0b,
+	0xaa, 0x58, 0xa7, 0xcc, 0xd0, 0x4c, 0xc5, 0x6e, 0xf5, 0xce, 0x1d, 0xc9, 0xe4, 0xec, 0xf2, 0x38,
+	0xc1, 0x3a, 0x65, 0x3e, 0x1a, 0x49, 0x0f, 0xb4, 0x22, 0xe6, 0x22, 0x37, 0xea, 0x98, 0xb8, 0xf8,
+	0x27, 0x11, 0x96, 0x1e, 0x5f, 0x5a, 0xad, 0x0e, 0xa8, 0xe5, 0x04, 0x72, 0x04, 0x7a, 0xf0, 0xfe,
+	0x3a, 0x9c, 0x86, 0x23, 0x37, 0x18, 0xf4, 0xdb, 0x15, 0xcb, 0x01, 0x0d, 0x8d, 0xa4, 0x05, 0x10,
+	0xba, 0xa3, 0x60, 0x32, 0x75, 0x3d, 0x77, 0xd8, 0xae, 0x90, 0x53, 0x38, 0xde, 0xfc, 0xdf, 0xbb,
+	0xde, 0x64, 0xf8, 0xe8, 0xb9, 0x4f, 0x93, 0xb6, 0x62, 0x3d, 0x03, 0x91, 0xe7, 0xf8, 0x6c, 0xce,
+	0x73, 0x91, 0x51, 0xbc, 0xf7, 0x0d, 0x34, 0xe4, 0x62, 0x73, 0x43, 0x31, 0x6b, 0xb6, 0xde, 0x3b,
+	0xdb, 0x0f, 0xe5, 0xff, 0xd8, 0x2c, 0x0f, 0x74, 0x29, 0xbd, 0xd1, 0x45, 0xc1, 0xf6, 0xae, 0xfb,
+	0x0a, 0x9a, 0x05, 0x8f, 0xc5, 0xa0, 0x3f, 0x5d, 0x95, 0x1e, 0xdc, 0xb7, 0xfa, 0x52, 0xf1, 0x75,
+	0xd9, 0xc5, 0xe0, 0x43, 0x03, 0x34, 0x54, 0xad, 0x3b, 0x68, 0xca, 0x81, 0x61, 0x3a, 0xa3, 0x82,
+	0x91, 0xeb, 0xbf, 0x48, 0x27, 0xbb, 0x48, 0x18, 0xff, 0xe5, 0xf9, 0xa8, 0xe3, 0x8b, 0xb8, 0xfd,
+	0x0e, 0x00, 0x00, 0xff, 0xff, 0x80, 0x9d, 0x7d, 0x0b, 0x2c, 0x02, 0x00, 0x00,
 }
diff --git a/pkg/sentry/fs/file.go b/pkg/sentry/fs/file.go
index 78100e448..846252c89 100644
--- a/pkg/sentry/fs/file.go
+++ b/pkg/sentry/fs/file.go
@@ -44,7 +44,7 @@ var (
 	RecordWaitTime = false
 
 	reads    = metric.MustCreateNewUint64Metric("/fs/reads", false /* sync */, "Number of file reads.")
-	readWait = metric.MustCreateNewUint64Metric("/fs/read_wait", false /* sync */, "Time waiting on file reads, in nanoseconds.")
+	readWait = metric.MustCreateNewUint64NanosecondsMetric("/fs/read_wait", false /* sync */, "Time waiting on file reads, in nanoseconds.")
 )
 
 // IncrementWait increments the given wait time metric, if enabled.
diff --git a/pkg/sentry/fs/gofer/file.go b/pkg/sentry/fs/gofer/file.go
index 23296f246..b2fcab127 100644
--- a/pkg/sentry/fs/gofer/file.go
+++ b/pkg/sentry/fs/gofer/file.go
@@ -37,9 +37,9 @@ var (
 	opens9P      = metric.MustCreateNewUint64Metric("/gofer/opens_9p", false /* sync */, "Number of times a 9P file was opened from a gofer.")
 	opensHost    = metric.MustCreateNewUint64Metric("/gofer/opens_host", false /* sync */, "Number of times a host file was opened from a gofer.")
 	reads9P      = metric.MustCreateNewUint64Metric("/gofer/reads_9p", false /* sync */, "Number of 9P file reads from a gofer.")
-	readWait9P   = metric.MustCreateNewUint64Metric("/gofer/read_wait_9p", false /* sync */, "Time waiting on 9P file reads from a gofer, in nanoseconds.")
+	readWait9P   = metric.MustCreateNewUint64NanosecondsMetric("/gofer/read_wait_9p", false /* sync */, "Time waiting on 9P file reads from a gofer, in nanoseconds.")
 	readsHost    = metric.MustCreateNewUint64Metric("/gofer/reads_host", false /* sync */, "Number of host file reads from a gofer.")
-	readWaitHost = metric.MustCreateNewUint64Metric("/gofer/read_wait_host", false /* sync */, "Time waiting on host file reads from a gofer, in nanoseconds.")
+	readWaitHost = metric.MustCreateNewUint64NanosecondsMetric("/gofer/read_wait_host", false /* sync */, "Time waiting on host file reads from a gofer, in nanoseconds.")
 )
 
 // fileOperations implements fs.FileOperations for a remote file system.
diff --git a/pkg/sentry/fs/tmpfs/inode_file.go b/pkg/sentry/fs/tmpfs/inode_file.go
index 25abbc151..1dc75291d 100644
--- a/pkg/sentry/fs/tmpfs/inode_file.go
+++ b/pkg/sentry/fs/tmpfs/inode_file.go
@@ -39,7 +39,7 @@ var (
 	opensRO  = metric.MustCreateNewUint64Metric("/in_memory_file/opens_ro", false /* sync */, "Number of times an in-memory file was opened in read-only mode.")
 	opensW   = metric.MustCreateNewUint64Metric("/in_memory_file/opens_w", false /* sync */, "Number of times an in-memory file was opened in write mode.")
 	reads    = metric.MustCreateNewUint64Metric("/in_memory_file/reads", false /* sync */, "Number of in-memory file reads.")
-	readWait = metric.MustCreateNewUint64Metric("/in_memory_file/read_wait", false /* sync */, "Time waiting on in-memory file reads, in nanoseconds.")
+	readWait = metric.MustCreateNewUint64NanosecondsMetric("/in_memory_file/read_wait", false /* sync */, "Time waiting on in-memory file reads, in nanoseconds.")
 )
 
 // fileInodeOperations implements fs.InodeOperations for a regular tmpfs file.
diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go
index 7ac38764d..d5879c10f 100755
--- a/pkg/sentry/socket/netstack/netstack.go
+++ b/pkg/sentry/socket/netstack/netstack.go
@@ -63,7 +63,13 @@ import (
 
 func mustCreateMetric(name, description string) *tcpip.StatCounter {
 	var cm tcpip.StatCounter
-	metric.MustRegisterCustomUint64Metric(name, false /* sync */, description, cm.Value)
+	metric.MustRegisterCustomUint64Metric(name, true /* cumulative */, false /* sync */, description, cm.Value)
+	return &cm
+}
+
+func mustCreateGauge(name, description string) *tcpip.StatCounter {
+	var cm tcpip.StatCounter
+	metric.MustRegisterCustomUint64Metric(name, false /* cumulative */, false /* sync */, description, cm.Value)
 	return &cm
 }
 
@@ -151,10 +157,10 @@ var Metrics = tcpip.Stats{
 	TCP: tcpip.TCPStats{
 		ActiveConnectionOpenings:           mustCreateMetric("/netstack/tcp/active_connection_openings", "Number of connections opened successfully via Connect."),
 		PassiveConnectionOpenings:          mustCreateMetric("/netstack/tcp/passive_connection_openings", "Number of connections opened successfully via Listen."),
-		CurrentEstablished:                 mustCreateMetric("/netstack/tcp/current_established", "Number of connections in ESTABLISHED state now."),
-		CurrentConnected:                   mustCreateMetric("/netstack/tcp/current_open", "Number of connections that are in connected state."),
+		CurrentEstablished:                 mustCreateGauge("/netstack/tcp/current_established", "Number of connections in ESTABLISHED state now."),
+		CurrentConnected:                   mustCreateGauge("/netstack/tcp/current_open", "Number of connections that are in connected state."),
 		EstablishedResets:                  mustCreateMetric("/netstack/tcp/established_resets", "Number of times TCP connections have made a direct transition to the CLOSED state from either the ESTABLISHED state or the CLOSE-WAIT state"),
-		EstablishedClosed:                  mustCreateMetric("/netstack/tcp/established_closed", "number of times established TCP connections made a transition to CLOSED state."),
+		EstablishedClosed:                  mustCreateMetric("/netstack/tcp/established_closed", "Number of times established TCP connections made a transition to CLOSED state."),
 		EstablishedTimedout:                mustCreateMetric("/netstack/tcp/established_timedout", "Number of times  an established connection was reset because of keep-alive time out."),
 		ListenOverflowSynDrop:              mustCreateMetric("/netstack/tcp/listen_overflow_syn_drop", "Number of times the listen queue overflowed and a SYN was dropped."),
 		ListenOverflowAckDrop:              mustCreateMetric("/netstack/tcp/listen_overflow_ack_drop", "Number of times the listen queue overflowed and the final ACK in the handshake was dropped."),