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tailscale/net/sockstats/sockstats_tsgo.go

378 lines
12 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
//go:build tailscale_go && (darwin || ios || android || ts_enable_sockstats)
package sockstats
import (
"context"
"fmt"
"net"
"strings"
"sync"
"sync/atomic"
"syscall"
"time"
"tailscale.com/net/interfaces"
"tailscale.com/types/logger"
"tailscale.com/util/clientmetric"
)
const IsAvailable = true
type sockStatCounters struct {
txBytes, rxBytes atomic.Uint64
rxBytesByInterface, txBytesByInterface map[int]*atomic.Uint64
txBytesMetric, rxBytesMetric, txBytesCellularMetric, rxBytesCellularMetric *clientmetric.Metric
// Validate counts for TCP sockets by using the TCP_CONNECTION_INFO
// getsockopt. We get current counts, as well as save final values when
// sockets are closed.
validationConn atomic.Pointer[syscall.RawConn]
validationTxBytes, validationRxBytes atomic.Uint64
}
var sockStats = struct {
// mu protects fields in this group (but not the fields within
// sockStatCounters). It should not be held in the per-read/write
// callbacks.
mu sync.Mutex
countersByLabel map[Label]*sockStatCounters
knownInterfaces map[int]string // interface index -> name
usedInterfaces map[int]int // set of interface indexes
// Separate atomic since the current interface is accessed in the per-read/
// write callbacks.
currentInterface atomic.Uint32
currentInterfaceCellular atomic.Bool
txBytesMetric, rxBytesMetric, txBytesCellularMetric, rxBytesCellularMetric *clientmetric.Metric
radioHighMetric *clientmetric.Metric
}{
countersByLabel: make(map[Label]*sockStatCounters),
knownInterfaces: make(map[int]string),
usedInterfaces: make(map[int]int),
txBytesMetric: clientmetric.NewCounter("sockstats_tx_bytes"),
rxBytesMetric: clientmetric.NewCounter("sockstats_rx_bytes"),
txBytesCellularMetric: clientmetric.NewCounter("sockstats_tx_bytes_cellular"),
rxBytesCellularMetric: clientmetric.NewCounter("sockstats_rx_bytes_cellular"),
radioHighMetric: clientmetric.NewGaugeFunc("sockstats_cellular_radio_high_fraction", radio.radioHighPercent),
}
func init() {
// Deltas are not useful for this gauge metric, we want the collector to be
// able to get current values without having to wait for the 4 hour
// metricLogNameFrequency interval (by which point the cell radio state may
// be very different).
sockStats.radioHighMetric.DisableDeltas()
}
func withSockStats(ctx context.Context, label Label, logf logger.Logf) context.Context {
sockStats.mu.Lock()
defer sockStats.mu.Unlock()
counters, ok := sockStats.countersByLabel[label]
if !ok {
counters = &sockStatCounters{
rxBytesByInterface: make(map[int]*atomic.Uint64),
txBytesByInterface: make(map[int]*atomic.Uint64),
txBytesMetric: clientmetric.NewCounter(fmt.Sprintf("sockstats_tx_bytes_%s", label)),
rxBytesMetric: clientmetric.NewCounter(fmt.Sprintf("sockstats_rx_bytes_%s", label)),
txBytesCellularMetric: clientmetric.NewCounter(fmt.Sprintf("sockstats_tx_bytes_cellular_%s", label)),
rxBytesCellularMetric: clientmetric.NewCounter(fmt.Sprintf("sockstats_rx_bytes_cellular_%s", label)),
}
// We might be called before setLinkMonitor has been called (and we've
// had a chance to populate knownInterfaces). In that case, we'll have
// to get the list of interfaces ourselves.
if len(sockStats.knownInterfaces) == 0 {
if ifaces, err := interfaces.GetList(); err == nil {
for _, iface := range ifaces {
counters.rxBytesByInterface[iface.Index] = &atomic.Uint64{}
counters.txBytesByInterface[iface.Index] = &atomic.Uint64{}
}
}
} else {
for iface := range sockStats.knownInterfaces {
counters.rxBytesByInterface[iface] = &atomic.Uint64{}
counters.txBytesByInterface[iface] = &atomic.Uint64{}
}
}
sockStats.countersByLabel[label] = counters
}
didCreateTCPConn := func(c syscall.RawConn) {
counters.validationConn.Store(&c)
}
willCloseTCPConn := func(c syscall.RawConn) {
tx, rx := tcpConnStats(c)
counters.validationTxBytes.Add(tx)
counters.validationRxBytes.Add(rx)
counters.validationConn.Store(nil)
}
// Don't bother adding these hooks if we can't get stats that they end up
// collecting.
if tcpConnStats == nil {
willCloseTCPConn = nil
didCreateTCPConn = nil
}
didRead := func(n int) {
counters.rxBytes.Add(uint64(n))
counters.rxBytesMetric.Add(int64(n))
sockStats.rxBytesMetric.Add(int64(n))
if currentInterface := int(sockStats.currentInterface.Load()); currentInterface != 0 {
if a := counters.rxBytesByInterface[currentInterface]; a != nil {
a.Add(uint64(n))
}
}
if sockStats.currentInterfaceCellular.Load() {
sockStats.rxBytesCellularMetric.Add(int64(n))
counters.rxBytesCellularMetric.Add(int64(n))
if n > 0 {
radio.active()
}
}
}
didWrite := func(n int) {
counters.txBytes.Add(uint64(n))
counters.txBytesMetric.Add(int64(n))
sockStats.txBytesMetric.Add(int64(n))
if currentInterface := int(sockStats.currentInterface.Load()); currentInterface != 0 {
if a := counters.txBytesByInterface[currentInterface]; a != nil {
a.Add(uint64(n))
}
}
if sockStats.currentInterfaceCellular.Load() {
sockStats.txBytesCellularMetric.Add(int64(n))
counters.txBytesCellularMetric.Add(int64(n))
if n > 0 {
radio.active()
}
}
}
willOverwrite := func(trace *net.SockTrace) {
logf("sockstats: trace %q was overwritten by another", label)
}
return net.WithSockTrace(ctx, &net.SockTrace{
DidCreateTCPConn: didCreateTCPConn,
DidRead: didRead,
DidWrite: didWrite,
WillOverwrite: willOverwrite,
WillCloseTCPConn: willCloseTCPConn,
})
}
// tcpConnStats returns the number of bytes sent and received on the
// given TCP socket. Its implementation is platform-dependent (or it may not
// be available at all).
var tcpConnStats func(c syscall.RawConn) (tx, rx uint64)
func get() *SockStats {
sockStats.mu.Lock()
defer sockStats.mu.Unlock()
r := &SockStats{
Stats: make(map[Label]SockStat, len(sockStats.countersByLabel)),
CurrentInterfaceCellular: sockStats.currentInterfaceCellular.Load(),
}
for label, counters := range sockStats.countersByLabel {
r.Stats[label] = SockStat{
TxBytes: counters.txBytes.Load(),
RxBytes: counters.rxBytes.Load(),
}
}
return r
}
func getInterfaces() *InterfaceSockStats {
sockStats.mu.Lock()
defer sockStats.mu.Unlock()
interfaceCount := len(sockStats.usedInterfaces)
r := &InterfaceSockStats{
Stats: make(map[Label]InterfaceSockStat, len(sockStats.countersByLabel)),
Interfaces: make([]string, 0, interfaceCount),
}
for iface := range sockStats.usedInterfaces {
r.Interfaces = append(r.Interfaces, sockStats.knownInterfaces[iface])
}
for label, counters := range sockStats.countersByLabel {
s := InterfaceSockStat{
TxBytesByInterface: make(map[string]uint64, interfaceCount),
RxBytesByInterface: make(map[string]uint64, interfaceCount),
}
for iface, a := range counters.rxBytesByInterface {
ifName := sockStats.knownInterfaces[iface]
s.RxBytesByInterface[ifName] = a.Load()
}
for iface, a := range counters.txBytesByInterface {
ifName := sockStats.knownInterfaces[iface]
s.TxBytesByInterface[ifName] = a.Load()
}
r.Stats[label] = s
}
return r
}
func getValidation() *ValidationSockStats {
sockStats.mu.Lock()
defer sockStats.mu.Unlock()
r := &ValidationSockStats{
Stats: make(map[Label]ValidationSockStat),
}
for label, counters := range sockStats.countersByLabel {
s := ValidationSockStat{
TxBytes: counters.validationTxBytes.Load(),
RxBytes: counters.validationRxBytes.Load(),
}
if c := counters.validationConn.Load(); c != nil && tcpConnStats != nil {
tx, rx := tcpConnStats(*c)
s.TxBytes += tx
s.RxBytes += rx
}
r.Stats[label] = s
}
return r
}
func setLinkMonitor(lm LinkMonitor) {
sockStats.mu.Lock()
defer sockStats.mu.Unlock()
// We intentionally populate all known interfaces now, so that we can
// increment stats for them without holding mu.
state := lm.InterfaceState()
for ifName, iface := range state.Interface {
sockStats.knownInterfaces[iface.Index] = ifName
}
if ifName := state.DefaultRouteInterface; ifName != "" {
ifIndex := state.Interface[ifName].Index
sockStats.currentInterface.Store(uint32(ifIndex))
sockStats.currentInterfaceCellular.Store(isLikelyCellularInterface(ifName))
sockStats.usedInterfaces[ifIndex] = 1
}
lm.RegisterChangeCallback(func(changed bool, state *interfaces.State) {
if changed {
if ifName := state.DefaultRouteInterface; ifName != "" {
ifIndex := state.Interface[ifName].Index
sockStats.mu.Lock()
defer sockStats.mu.Unlock()
// Ignore changes to unknown interfaces -- it would require
// updating the tx/rxBytesByInterface maps and thus
// additional locking for every read/write. Most of the time
// the set of interfaces is static.
if _, ok := sockStats.knownInterfaces[ifIndex]; ok {
sockStats.currentInterface.Store(uint32(ifIndex))
sockStats.usedInterfaces[ifIndex] = 1
sockStats.currentInterfaceCellular.Store(isLikelyCellularInterface(ifName))
} else {
sockStats.currentInterface.Store(0)
sockStats.currentInterfaceCellular.Store(false)
}
}
}
})
}
func isLikelyCellularInterface(ifName string) bool {
return strings.HasPrefix(ifName, "rmnet") || // Android
strings.HasPrefix(ifName, "ww") || // systemd naming scheme for WWAN
strings.HasPrefix(ifName, "pdp") // iOS
}
// radioMonitor tracks usage of the cellular radio, approximates the power state transitions,
// and reports the percentage of time the radio was on.
type radioMonitor struct {
// usage tracks the last time (as unix timestamp) the radio was used over the last hour.
// Values are indexed by the number of seconds since the beginning of the current hour.
usage [radioSampleSize]int64
// startTime is the time we started tracking radio usage.
startTime int64
now func() time.Time
}
// radioSampleSize is the number of samples to store and report for cellular radio usage.
// Usage is measured once per second, so this is the number of seconds of history to track.
const radioSampleSize = 3600 // 1 hour
var radio = &radioMonitor{
now: time.Now,
startTime: time.Now().Unix(),
}
// radioActivity should be called whenever network activity occurs on a cellular network interface.
func (rm *radioMonitor) active() {
t := rm.now().Unix()
rm.usage[t%radioSampleSize] = t
}
// Timings for radio power state transitions taken from
// https://developer.android.com/training/connectivity/network-access-optimization#radio-state
// Even though that documents a typical 3G radio and newer radios are much more efficient,
// it provides worst-case timings to use for analysis.
const (
radioHighIdle = 5 // seconds radio idles in high power state before transitioning to low
radioLowIdle = 12 // seconds radio idles in low power state before transitioning to off
)
// radioHighPercent returns the percentage of time (as an int from 0 to 100)
// that the cellular radio was in high power mode during the past hour.
// If the radio has been monitored for less than an hour,
// the percentage is calculated based on the time monitored.
func (rm *radioMonitor) radioHighPercent() int64 {
now := rm.now().Unix()
var periodLength int64 = radioSampleSize
if t := now - rm.startTime; t < periodLength {
if t <= 0 {
return 0
}
periodLength = t
}
periodStart := now - periodLength // start of current reporting period
// split into slices of radio usage, with values in chronological order.
// split at now+1 so that the current second is in the second slice.
split := (now + 1) % radioSampleSize
slices := [2][]int64{
rm.usage[split:],
rm.usage[:split],
}
var highPowerSec int64 // total seconds radio was in high power (active or idle)
var c int // counter
var lastActive int // counter when radio was last active
for _, slice := range slices {
for _, v := range slice {
c++ // increment first so we don't have zero values
if v >= periodStart {
// radio on and active
highPowerSec++
lastActive = c
} else if lastActive > 0 && c-lastActive < radioHighIdle {
// radio on but idle
highPowerSec++
}
}
}
if highPowerSec == 0 {
return 0
}
return highPowerSec * 100 / periodLength
}