mirror of
https://github.com/tailscale/tailscale.git
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cmd/stunstamp: implement service to measure DERP STUN RTT (#12241)
stunstamp timestamping includes userspace and SO_TIMESTAMPING kernel timestamping where available. Measurements are written locally to a sqlite DB, exposed over an HTTP API, and written to prometheus via remote-write protocol. Updates tailscale/corp#20344 Signed-off-by: Jordan Whited <jordan@tailscale.com>
This commit is contained in:
Jordan Whited
141
cmd/stunstamp/api.go
Normal file
141
cmd/stunstamp/api.go
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@@ -0,0 +1,141 @@
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// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package main
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import (
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"compress/gzip"
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"encoding/json"
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"errors"
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"net/http"
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"net/url"
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"strconv"
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"strings"
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"time"
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sq "github.com/Masterminds/squirrel"
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)
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type api struct {
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db *db
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mux *http.ServeMux
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}
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func newAPI(db *db) *api {
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a := &api{
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db: db,
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}
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mux := http.NewServeMux()
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mux.HandleFunc("/query", a.query)
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a.mux = mux
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return a
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}
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type apiResult struct {
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At int `json:"at"` // time.Time.Unix()
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RegionID int `json:"regionID"`
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Hostname string `json:"hostname"`
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Af int `json:"af"` // 4 or 6
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Addr string `json:"addr"`
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Source int `json:"source"` // timestampSourceUserspace (0) or timestampSourceKernel (1)
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StableConn bool `json:"stableConn"`
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RttNS *int `json:"rttNS"`
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}
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func getTimeBounds(vals url.Values) (from time.Time, to time.Time, err error) {
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lastForm, ok := vals["last"]
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if ok && len(lastForm) > 0 {
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dur, err := time.ParseDuration(lastForm[0])
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if err != nil {
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return time.Time{}, time.Time{}, err
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}
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now := time.Now()
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return now.Add(-dur), now, nil
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}
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fromForm, ok := vals["from"]
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if ok && len(fromForm) > 0 {
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fromUnixSec, err := strconv.Atoi(fromForm[0])
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if err != nil {
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return time.Time{}, time.Time{}, err
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}
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from = time.Unix(int64(fromUnixSec), 0)
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toForm, ok := vals["to"]
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if ok && len(toForm) > 0 {
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toUnixSec, err := strconv.Atoi(toForm[0])
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if err != nil {
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return time.Time{}, time.Time{}, err
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}
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to = time.Unix(int64(toUnixSec), 0)
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} else {
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return time.Time{}, time.Time{}, errors.New("from specified without to")
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}
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return from, to, nil
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}
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// no time bounds specified, default to last 1h
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now := time.Now()
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return now.Add(-time.Hour), now, nil
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}
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func (a *api) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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a.mux.ServeHTTP(w, r)
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}
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func (a *api) query(w http.ResponseWriter, r *http.Request) {
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err := r.ParseForm()
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if err != nil {
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http.Error(w, err.Error(), 500)
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return
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}
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from, to, err := getTimeBounds(r.Form)
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if err != nil {
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http.Error(w, err.Error(), 500)
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return
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}
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sb := sq.Select("at_unix", "region_id", "hostname", "af", "address", "timestamp_source", "stable_conn", "rtt_ns").From("rtt")
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sb = sb.Where(sq.And{
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sq.GtOrEq{"at_unix": from.Unix()},
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sq.LtOrEq{"at_unix": to.Unix()},
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})
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query, args, err := sb.ToSql()
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if err != nil {
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return
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}
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rows, err := a.db.Query(query, args...)
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if err != nil {
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http.Error(w, err.Error(), 500)
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return
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}
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results := make([]apiResult, 0)
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for rows.Next() {
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rtt := 0
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result := apiResult{
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RttNS: &rtt,
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}
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err = rows.Scan(&result.At, &result.RegionID, &result.Hostname, &result.Af, &result.Addr, &result.Source, &result.StableConn, &result.RttNS)
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if err != nil {
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http.Error(w, err.Error(), 500)
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return
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}
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results = append(results, result)
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}
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if rows.Err() != nil {
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http.Error(w, rows.Err().Error(), 500)
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return
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}
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if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
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gz := gzip.NewWriter(w)
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defer gz.Close()
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w.Header().Set("Content-Encoding", "gzip")
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err = json.NewEncoder(gz).Encode(&results)
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} else {
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err = json.NewEncoder(w).Encode(&results)
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}
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if err != nil {
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http.Error(w, err.Error(), 500)
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return
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}
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}
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782
cmd/stunstamp/stunstamp.go
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782
cmd/stunstamp/stunstamp.go
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@@ -0,0 +1,782 @@
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// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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// The stunstamp binary measures STUN round-trip latency with DERPs.
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package main
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import (
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"bytes"
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"cmp"
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"context"
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"encoding/json"
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"errors"
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"flag"
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"fmt"
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"io"
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"log"
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"math"
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"math/rand"
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"net"
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"net/http"
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"net/netip"
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"net/url"
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"os"
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"os/signal"
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"slices"
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"sync"
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"syscall"
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"time"
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"github.com/golang/snappy"
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"github.com/prometheus/prometheus/prompb"
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"tailscale.com/logtail/backoff"
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"tailscale.com/net/stun"
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"tailscale.com/tailcfg"
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)
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var (
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flagDERPMap = flag.String("derp-map", "https://login.tailscale.com/derpmap/default", "URL to DERP map")
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flagOut = flag.String("out", "", "output sqlite filename")
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flagInterval = flag.Duration("interval", time.Minute, "interval to probe at in time.ParseDuration() format")
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flagAPI = flag.String("api", "", "listen addr for HTTP API")
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flagIPv6 = flag.Bool("ipv6", false, "probe IPv6 addresses")
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flagRetention = flag.Duration("retention", time.Hour*24*7, "sqlite retention period in time.ParseDuration() format")
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flagRemoteWriteURL = flag.String("rw-url", "", "prometheus remote write URL")
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flagInstance = flag.String("instance", "", "instance label value; defaults to hostname if unspecified")
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)
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const (
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minInterval = time.Second
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maxBufferDuration = time.Hour
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)
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func getDERPMap(ctx context.Context, url string) (*tailcfg.DERPMap, error) {
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req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
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if err != nil {
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return nil, err
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}
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resp, err := http.DefaultClient.Do(req)
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if err != nil {
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return nil, err
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}
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defer resp.Body.Close()
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dm := tailcfg.DERPMap{}
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err = json.NewDecoder(resp.Body).Decode(&dm)
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if err != nil {
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return nil, nil
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}
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return &dm, nil
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}
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type timestampSource int
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const (
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timestampSourceUserspace timestampSource = iota
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timestampSourceKernel
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)
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func (t timestampSource) String() string {
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switch t {
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case timestampSourceUserspace:
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return "userspace"
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case timestampSourceKernel:
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return "kernel"
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default:
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return "unknown"
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}
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}
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type result struct {
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at time.Time
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meta nodeMeta
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timestampSource timestampSource
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connStability connStability
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rtt *time.Duration // nil signifies failure, e.g. timeout
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}
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func measureRTT(conn io.ReadWriteCloser, dst *net.UDPAddr, req []byte) (resp []byte, rtt time.Duration, err error) {
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uconn, ok := conn.(*net.UDPConn)
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if !ok {
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return nil, 0, fmt.Errorf("unexpected conn type: %T", conn)
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}
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err = uconn.SetReadDeadline(time.Now().Add(time.Second * 2))
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if err != nil {
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return nil, 0, fmt.Errorf("error setting read deadline: %w", err)
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}
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txAt := time.Now()
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_, err = uconn.WriteToUDP(req, dst)
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if err != nil {
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return nil, 0, fmt.Errorf("error writing to udp socket: %w", err)
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}
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b := make([]byte, 1460)
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n, err := uconn.Read(b)
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rxAt := time.Now()
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if err != nil {
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return nil, 0, fmt.Errorf("error reading from udp socket: %w", err)
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}
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return b[:n], rxAt.Sub(txAt), nil
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}
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func isTemporaryOrTimeoutErr(err error) bool {
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if errors.Is(err, os.ErrDeadlineExceeded) || errors.Is(err, context.DeadlineExceeded) {
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return true
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}
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if err, ok := err.(interface{ Temporary() bool }); ok {
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return err.Temporary()
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}
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return false
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}
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type nodeMeta struct {
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regionID int
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regionCode string
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hostname string
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addr netip.Addr
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}
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type measureFn func(conn io.ReadWriteCloser, dst *net.UDPAddr, req []byte) (resp []byte, rtt time.Duration, err error)
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func probe(meta nodeMeta, conn io.ReadWriteCloser, fn measureFn) (*time.Duration, error) {
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ua := &net.UDPAddr{
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IP: net.IP(meta.addr.AsSlice()),
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Port: 3478,
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}
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var (
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resp []byte
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rtt time.Duration
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)
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txID := stun.NewTxID()
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req := stun.Request(txID)
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time.Sleep(time.Millisecond * time.Duration(rand.Intn(200))) // jitter across tx
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resp, rtt, err := fn(conn, ua, req)
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if err != nil {
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if isTemporaryOrTimeoutErr(err) {
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log.Printf("temp error measuring RTT to %s(%s): %v", meta.hostname, meta.addr, err)
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return nil, nil
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}
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}
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_, _, err = stun.ParseResponse(resp)
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if err != nil {
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log.Printf("invalid stun response from %s: %v", meta.hostname, err)
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return nil, nil
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}
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return &rtt, nil
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}
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func nodeMetaFromDERPMap(dm *tailcfg.DERPMap, nodeMetaByAddr map[netip.Addr]nodeMeta, ipv6 bool) (stale []nodeMeta, err error) {
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// Parse the new derp map before making any state changes in nodeMetaByAddr.
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// If parse fails we just stick with the old state.
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updated := make(map[netip.Addr]nodeMeta)
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for regionID, region := range dm.Regions {
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for _, node := range region.Nodes {
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v4, err := netip.ParseAddr(node.IPv4)
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if err != nil || !v4.Is4() {
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return nil, fmt.Errorf("invalid ipv4 addr for node in derp map: %v", node.Name)
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}
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metas := make([]nodeMeta, 0, 2)
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metas = append(metas, nodeMeta{
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regionID: regionID,
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regionCode: region.RegionCode,
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hostname: node.HostName,
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addr: v4,
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})
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if ipv6 {
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v6, err := netip.ParseAddr(node.IPv6)
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if err != nil || !v6.Is6() {
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return nil, fmt.Errorf("invalid ipv6 addr for node in derp map: %v", node.Name)
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}
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metas = append(metas, metas[0])
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metas[1].addr = v6
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}
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for _, meta := range metas {
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updated[meta.addr] = meta
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}
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}
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}
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// Find nodeMeta that have changed
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for addr, updatedMeta := range updated {
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previousMeta, ok := nodeMetaByAddr[addr]
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if ok {
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if previousMeta == updatedMeta {
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continue
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}
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stale = append(stale, previousMeta)
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nodeMetaByAddr[addr] = updatedMeta
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} else {
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nodeMetaByAddr[addr] = updatedMeta
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}
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}
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// Find nodeMeta that no longer exist
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for addr, potentialStale := range nodeMetaByAddr {
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_, ok := updated[addr]
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if !ok {
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stale = append(stale, potentialStale)
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}
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}
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return stale, nil
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}
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func getStableConns(stableConns map[netip.Addr][2]io.ReadWriteCloser, addr netip.Addr) ([2]io.ReadWriteCloser, error) {
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conns, ok := stableConns[addr]
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if ok {
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return conns, nil
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}
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if supportsKernelTS() {
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kconn, err := getConnKernelTimestamp()
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if err != nil {
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return conns, err
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}
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conns[timestampSourceKernel] = kconn
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}
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uconn, err := net.ListenUDP("udp", &net.UDPAddr{})
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if err != nil {
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return conns, err
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}
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conns[timestampSourceUserspace] = uconn
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stableConns[addr] = conns
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return conns, nil
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}
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// probeNodes measures the round-trip time for STUN binding requests against the
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// DERP nodes described by nodeMetaByAddr while using/updating stableConns for
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// UDP sockets that should be recycled across runs. It returns the results or
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// an error if one occurs.
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func probeNodes(nodeMetaByAddr map[netip.Addr]nodeMeta, stableConns map[netip.Addr][2]io.ReadWriteCloser) ([]result, error) {
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wg := sync.WaitGroup{}
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results := make([]result, 0)
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resultsCh := make(chan result)
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errCh := make(chan error)
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doneCh := make(chan struct{})
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numProbes := 0
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at := time.Now()
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addrsToProbe := make(map[netip.Addr]bool)
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doProbe := func(conn io.ReadWriteCloser, meta nodeMeta, source timestampSource) {
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defer wg.Done()
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r := result{}
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if conn == nil {
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var err error
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if source == timestampSourceKernel {
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conn, err = getConnKernelTimestamp()
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} else {
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conn, err = net.ListenUDP("udp", &net.UDPAddr{})
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}
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if err != nil {
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select {
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case <-doneCh:
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return
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case errCh <- err:
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return
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}
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}
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defer conn.Close()
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} else {
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r.connStability = stableConn
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}
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fn := measureRTT
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if source == timestampSourceKernel {
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fn = measureRTTKernel
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}
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rtt, err := probe(meta, conn, fn)
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if err != nil {
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select {
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case <-doneCh:
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return
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case errCh <- err:
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return
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}
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}
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r.at = at
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r.meta = meta
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r.timestampSource = source
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r.rtt = rtt
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select {
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case <-doneCh:
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case resultsCh <- r:
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}
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}
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|
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for _, meta := range nodeMetaByAddr {
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addrsToProbe[meta.addr] = true
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stable, err := getStableConns(stableConns, meta.addr)
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if err != nil {
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close(doneCh)
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wg.Wait()
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return nil, err
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}
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|
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wg.Add(2)
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numProbes += 2
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go doProbe(stable[timestampSourceUserspace], meta, timestampSourceUserspace)
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go doProbe(nil, meta, timestampSourceUserspace)
|
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if supportsKernelTS() {
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wg.Add(2)
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numProbes += 2
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go doProbe(stable[timestampSourceKernel], meta, timestampSourceKernel)
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go doProbe(nil, meta, timestampSourceKernel)
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}
|
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}
|
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|
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// cleanup conns we no longer need
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for k, conns := range stableConns {
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if !addrsToProbe[k] {
|
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if conns[timestampSourceKernel] != nil {
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conns[timestampSourceKernel].Close()
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}
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conns[timestampSourceUserspace].Close()
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delete(stableConns, k)
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||||
}
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||||
}
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|
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for {
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||||
select {
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case err := <-errCh:
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||||
close(doneCh)
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||||
wg.Wait()
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return nil, err
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case result := <-resultsCh:
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||||
results = append(results, result)
|
||||
if len(results) == numProbes {
|
||||
return results, nil
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
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type connStability bool
|
||||
|
||||
const (
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||||
unstableConn connStability = false
|
||||
stableConn connStability = true
|
||||
)
|
||||
|
||||
func timeSeriesLabels(meta nodeMeta, instance string, source timestampSource, stability connStability) []prompb.Label {
|
||||
addressFamily := "ipv4"
|
||||
if meta.addr.Is6() {
|
||||
addressFamily = "ipv6"
|
||||
}
|
||||
labels := make([]prompb.Label, 0)
|
||||
labels = append(labels, prompb.Label{
|
||||
Name: "job",
|
||||
Value: "stunstamp-rw",
|
||||
})
|
||||
labels = append(labels, prompb.Label{
|
||||
Name: "instance",
|
||||
Value: instance,
|
||||
})
|
||||
labels = append(labels, prompb.Label{
|
||||
Name: "region_id",
|
||||
Value: fmt.Sprintf("%d", meta.regionID),
|
||||
})
|
||||
labels = append(labels, prompb.Label{
|
||||
Name: "region_code",
|
||||
Value: meta.regionCode,
|
||||
})
|
||||
labels = append(labels, prompb.Label{
|
||||
Name: "address_family",
|
||||
Value: addressFamily,
|
||||
})
|
||||
labels = append(labels, prompb.Label{
|
||||
Name: "hostname",
|
||||
Value: meta.hostname,
|
||||
})
|
||||
labels = append(labels, prompb.Label{
|
||||
Name: "__name__",
|
||||
Value: "stunstamp_derp_stun_rtt_ns",
|
||||
})
|
||||
labels = append(labels, prompb.Label{
|
||||
Name: "timestamp_source",
|
||||
Value: source.String(),
|
||||
})
|
||||
labels = append(labels, prompb.Label{
|
||||
Name: "stable_conn",
|
||||
Value: fmt.Sprintf("%v", stability),
|
||||
})
|
||||
slices.SortFunc(labels, func(a, b prompb.Label) int {
|
||||
// prometheus remote-write spec requires lexicographically sorted label names
|
||||
return cmp.Compare(a.Name, b.Name)
|
||||
})
|
||||
return labels
|
||||
}
|
||||
|
||||
const (
|
||||
// https://prometheus.io/docs/concepts/remote_write_spec/#stale-markers
|
||||
staleNaN uint64 = 0x7ff0000000000002
|
||||
)
|
||||
|
||||
func staleMarkersFromNodeMeta(stale []nodeMeta, instance string) []prompb.TimeSeries {
|
||||
staleMarkers := make([]prompb.TimeSeries, 0)
|
||||
now := time.Now()
|
||||
for _, s := range stale {
|
||||
samples := []prompb.Sample{
|
||||
{
|
||||
Timestamp: now.UnixMilli(),
|
||||
Value: math.Float64frombits(staleNaN),
|
||||
},
|
||||
}
|
||||
staleMarkers = append(staleMarkers, prompb.TimeSeries{
|
||||
Labels: timeSeriesLabels(s, instance, timestampSourceUserspace, unstableConn),
|
||||
Samples: samples,
|
||||
})
|
||||
staleMarkers = append(staleMarkers, prompb.TimeSeries{
|
||||
Labels: timeSeriesLabels(s, instance, timestampSourceUserspace, stableConn),
|
||||
Samples: samples,
|
||||
})
|
||||
if supportsKernelTS() {
|
||||
staleMarkers = append(staleMarkers, prompb.TimeSeries{
|
||||
Labels: timeSeriesLabels(s, instance, timestampSourceKernel, unstableConn),
|
||||
Samples: samples,
|
||||
})
|
||||
staleMarkers = append(staleMarkers, prompb.TimeSeries{
|
||||
Labels: timeSeriesLabels(s, instance, timestampSourceKernel, stableConn),
|
||||
Samples: samples,
|
||||
})
|
||||
}
|
||||
}
|
||||
return staleMarkers
|
||||
}
|
||||
|
||||
func resultToPromTimeSeries(r result, instance string) prompb.TimeSeries {
|
||||
labels := timeSeriesLabels(r.meta, instance, r.timestampSource, r.connStability)
|
||||
samples := make([]prompb.Sample, 1)
|
||||
samples[0].Timestamp = r.at.UnixMilli()
|
||||
if r.rtt != nil {
|
||||
samples[0].Value = float64(*r.rtt)
|
||||
} else {
|
||||
samples[0].Value = math.NaN()
|
||||
// TODO: timeout counter
|
||||
}
|
||||
ts := prompb.TimeSeries{
|
||||
Labels: labels,
|
||||
Samples: samples,
|
||||
}
|
||||
slices.SortFunc(ts.Labels, func(a, b prompb.Label) int {
|
||||
// prometheus remote-write spec requires lexicographically sorted label names
|
||||
return cmp.Compare(a.Name, b.Name)
|
||||
})
|
||||
return ts
|
||||
}
|
||||
|
||||
type remoteWriteClient struct {
|
||||
c *http.Client
|
||||
url string
|
||||
}
|
||||
|
||||
type recoverableErr struct {
|
||||
error
|
||||
}
|
||||
|
||||
func newRemoteWriteClient(url string) *remoteWriteClient {
|
||||
return &remoteWriteClient{
|
||||
c: &http.Client{
|
||||
Timeout: time.Second * 30,
|
||||
},
|
||||
url: url,
|
||||
}
|
||||
}
|
||||
|
||||
func (r *remoteWriteClient) write(ctx context.Context, ts []prompb.TimeSeries) error {
|
||||
wr := &prompb.WriteRequest{
|
||||
Timeseries: ts,
|
||||
}
|
||||
b, err := wr.Marshal()
|
||||
if err != nil {
|
||||
return fmt.Errorf("unable to marshal write request: %w", err)
|
||||
}
|
||||
compressed := snappy.Encode(nil, b)
|
||||
req, err := http.NewRequestWithContext(ctx, "POST", r.url, bytes.NewReader(compressed))
|
||||
if err != nil {
|
||||
return fmt.Errorf("unable to create write request: %w", err)
|
||||
}
|
||||
req.Header.Add("Content-Encoding", "snappy")
|
||||
req.Header.Set("Content-Type", "application/x-protobuf")
|
||||
req.Header.Set("User-Agent", "stunstamp")
|
||||
req.Header.Set("X-Prometheus-Remote-Write-Version", "0.1.0")
|
||||
resp, err := r.c.Do(req)
|
||||
if err != nil {
|
||||
return recoverableErr{fmt.Errorf("error performing write request: %w", err)}
|
||||
}
|
||||
if resp.StatusCode/100 != 2 {
|
||||
err = fmt.Errorf("remote server %s returned HTTP status %d", r.url, resp.StatusCode)
|
||||
}
|
||||
if resp.StatusCode/100 == 5 || resp.StatusCode == http.StatusTooManyRequests {
|
||||
return recoverableErr{err}
|
||||
}
|
||||
return err
|
||||
}
|
||||
|
||||
func remoteWriteTimeSeries(client *remoteWriteClient, tsCh chan []prompb.TimeSeries) {
|
||||
bo := backoff.NewBackoff("remote-write", log.Printf, time.Second*30)
|
||||
for ts := range tsCh {
|
||||
for {
|
||||
reqCtx, cancel := context.WithTimeout(context.Background(), time.Second*30)
|
||||
err := client.write(reqCtx, ts)
|
||||
cancel()
|
||||
// we could parse the Retry-After header, but use a simple exp
|
||||
// backoff for now
|
||||
bo.BackOff(context.Background(), err)
|
||||
if err == nil {
|
||||
break
|
||||
}
|
||||
var re recoverableErr
|
||||
if !errors.Is(err, &re) {
|
||||
log.Printf("unrecoverable remote write error: %v", err)
|
||||
break
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func main() {
|
||||
flag.Parse()
|
||||
if len(*flagDERPMap) < 1 {
|
||||
log.Fatal("derp-map flag is unset")
|
||||
}
|
||||
if len(*flagOut) < 1 {
|
||||
log.Fatal("out flag is unset")
|
||||
}
|
||||
if *flagInterval < minInterval || *flagInterval > maxBufferDuration {
|
||||
log.Fatalf("interval must be >= %s and <= %s", minInterval, maxBufferDuration)
|
||||
}
|
||||
if *flagRetention < *flagInterval {
|
||||
log.Fatalf("retention must be >= interval")
|
||||
}
|
||||
if len(*flagRemoteWriteURL) < 1 {
|
||||
log.Fatalf("rw-url flag is unset")
|
||||
}
|
||||
_, err := url.Parse(*flagRemoteWriteURL)
|
||||
if err != nil {
|
||||
log.Fatalf("invalid rw-url flag value: %v", err)
|
||||
}
|
||||
if len(*flagInstance) < 1 {
|
||||
hostname, err := os.Hostname()
|
||||
if err != nil {
|
||||
log.Fatalf("failed to get hostname: %v", err)
|
||||
}
|
||||
*flagInstance = hostname
|
||||
}
|
||||
|
||||
sigCh := make(chan os.Signal, 1)
|
||||
signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
|
||||
dmCh := make(chan *tailcfg.DERPMap)
|
||||
|
||||
go func() {
|
||||
bo := backoff.NewBackoff("derp-map", log.Printf, time.Second*30)
|
||||
for {
|
||||
ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
|
||||
dm, err := getDERPMap(ctx, *flagDERPMap)
|
||||
cancel()
|
||||
bo.BackOff(context.Background(), err)
|
||||
if err != nil {
|
||||
continue
|
||||
}
|
||||
dmCh <- dm
|
||||
return
|
||||
}
|
||||
}()
|
||||
|
||||
nodeMetaByAddr := make(map[netip.Addr]nodeMeta)
|
||||
select {
|
||||
case <-sigCh:
|
||||
return
|
||||
case dm := <-dmCh:
|
||||
_, err := nodeMetaFromDERPMap(dm, nodeMetaByAddr, *flagIPv6)
|
||||
if err != nil {
|
||||
log.Fatalf("error parsing derp map on startup: %v", err)
|
||||
}
|
||||
}
|
||||
|
||||
db, err := newDB(*flagOut)
|
||||
if err != nil {
|
||||
log.Fatalf("error opening output file for writing: %v", err)
|
||||
}
|
||||
defer db.Close()
|
||||
|
||||
_, err = db.Exec("PRAGMA journal_mode=WAL")
|
||||
if err != nil {
|
||||
log.Fatalf("error enabling WAL mode: %v", err)
|
||||
}
|
||||
|
||||
// No indices or primary key. Keep it simple for now. Reads will be full
|
||||
// scans. We can AUTOINCREMENT rowid in the future and hold an in-memory
|
||||
// index to at_unix if needed as reads are almost always going to be
|
||||
// time-bound (e.g. WHERE at_unix >= ?). At the time of authorship we have
|
||||
// ~300 data points per-interval w/o ipv6 w/kernel timestamping resulting
|
||||
// in ~2.6m rows in 24h w/a 10s probe interval.
|
||||
_, err = db.Exec(`
|
||||
CREATE TABLE IF NOT EXISTS rtt(at_unix INT, region_id INT, hostname TEXT, af INT, address TEXT, timestamp_source INT, stable_conn INT, rtt_ns INT)
|
||||
`)
|
||||
if err != nil {
|
||||
log.Fatalf("error initializing db: %v", err)
|
||||
}
|
||||
|
||||
wg := sync.WaitGroup{}
|
||||
httpErrCh := make(chan error, 1)
|
||||
var httpServer *http.Server
|
||||
if len(*flagAPI) > 0 {
|
||||
api := newAPI(db)
|
||||
httpServer = &http.Server{
|
||||
Addr: *flagAPI,
|
||||
Handler: api,
|
||||
ReadTimeout: time.Second * 60,
|
||||
WriteTimeout: time.Second * 60,
|
||||
}
|
||||
wg.Add(1)
|
||||
go func() {
|
||||
err := httpServer.ListenAndServe()
|
||||
httpErrCh <- err
|
||||
wg.Done()
|
||||
}()
|
||||
}
|
||||
|
||||
tsCh := make(chan []prompb.TimeSeries, maxBufferDuration / *flagInterval)
|
||||
remoteWriteDoneCh := make(chan struct{})
|
||||
rwc := newRemoteWriteClient(*flagRemoteWriteURL)
|
||||
go func() {
|
||||
remoteWriteTimeSeries(rwc, tsCh)
|
||||
close(remoteWriteDoneCh)
|
||||
}()
|
||||
|
||||
shutdown := func() {
|
||||
if httpServer != nil {
|
||||
httpServer.Close()
|
||||
}
|
||||
close(tsCh)
|
||||
select {
|
||||
case <-time.After(time.Second * 10): // give goroutine some time to flush
|
||||
case <-remoteWriteDoneCh:
|
||||
}
|
||||
|
||||
// send stale markers on shutdown
|
||||
staleMeta := make([]nodeMeta, 0, len(nodeMetaByAddr))
|
||||
for _, v := range nodeMetaByAddr {
|
||||
staleMeta = append(staleMeta, v)
|
||||
}
|
||||
staleMarkers := staleMarkersFromNodeMeta(staleMeta, *flagInstance)
|
||||
if len(staleMarkers) > 0 {
|
||||
ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
|
||||
rwc.write(ctx, staleMarkers)
|
||||
cancel()
|
||||
}
|
||||
|
||||
wg.Wait()
|
||||
return
|
||||
}
|
||||
|
||||
log.Println("stunstamp started")
|
||||
|
||||
// Re-using sockets means we get the same 5-tuple across runs. This results
|
||||
// in a higher probability of the packets traversing the same underlay path.
|
||||
// Comparison of stable and unstable 5-tuple results can shed light on
|
||||
// differences between paths where hashing (multipathing/load balancing)
|
||||
// comes into play.
|
||||
stableConns := make(map[netip.Addr][2]io.ReadWriteCloser)
|
||||
|
||||
derpMapTicker := time.NewTicker(time.Minute * 5)
|
||||
defer derpMapTicker.Stop()
|
||||
probeTicker := time.NewTicker(*flagInterval)
|
||||
defer probeTicker.Stop()
|
||||
cleanupTicker := time.NewTicker(time.Hour)
|
||||
defer cleanupTicker.Stop()
|
||||
|
||||
for {
|
||||
select {
|
||||
case <-cleanupTicker.C:
|
||||
older := time.Now().Add(-*flagRetention)
|
||||
log.Printf("cleaning up measurements older than %v", older)
|
||||
_, err := db.Exec("DELETE FROM rtt WHERE at_unix < ?", older.Unix())
|
||||
if err != nil {
|
||||
log.Printf("error cleaning up old data: %v", err)
|
||||
shutdown()
|
||||
return
|
||||
}
|
||||
case <-probeTicker.C:
|
||||
results, err := probeNodes(nodeMetaByAddr, stableConns)
|
||||
if err != nil {
|
||||
log.Printf("unrecoverable error while probing: %v", err)
|
||||
shutdown()
|
||||
return
|
||||
}
|
||||
ts := make([]prompb.TimeSeries, 0, len(results))
|
||||
for _, r := range results {
|
||||
ts = append(ts, resultToPromTimeSeries(r, *flagInstance))
|
||||
}
|
||||
select {
|
||||
case tsCh <- ts:
|
||||
default:
|
||||
select {
|
||||
case <-tsCh:
|
||||
log.Println("prometheus remote-write buffer full, dropped measurements")
|
||||
default:
|
||||
tsCh <- ts
|
||||
}
|
||||
}
|
||||
tx, err := db.Begin()
|
||||
if err != nil {
|
||||
log.Printf("error beginning sqlite tx: %v", err)
|
||||
shutdown()
|
||||
return
|
||||
}
|
||||
for _, result := range results {
|
||||
af := 4
|
||||
if result.meta.addr.Is6() {
|
||||
af = 6
|
||||
}
|
||||
_, err = tx.Exec("INSERT INTO rtt(at_unix, region_id, hostname, af, address, timestamp_source, stable_conn, rtt_ns) VALUES(?, ?, ?, ?, ?, ?, ?, ?)",
|
||||
result.at.Unix(), result.meta.regionID, result.meta.hostname, af, result.meta.addr.String(), result.timestampSource, result.connStability, result.rtt)
|
||||
if err != nil {
|
||||
tx.Rollback()
|
||||
log.Printf("error adding result to tx: %v", err)
|
||||
shutdown()
|
||||
return
|
||||
}
|
||||
}
|
||||
err = tx.Commit()
|
||||
if err != nil {
|
||||
log.Printf("error committing tx: %v", err)
|
||||
shutdown()
|
||||
return
|
||||
}
|
||||
case dm := <-dmCh:
|
||||
staleMeta, err := nodeMetaFromDERPMap(dm, nodeMetaByAddr, *flagIPv6)
|
||||
if err != nil {
|
||||
log.Printf("error parsing DERP map, continuing with stale map: %v", err)
|
||||
continue
|
||||
}
|
||||
staleMarkers := staleMarkersFromNodeMeta(staleMeta, *flagInstance)
|
||||
if len(staleMarkers) < 1 {
|
||||
continue
|
||||
}
|
||||
select {
|
||||
case tsCh <- staleMarkers:
|
||||
default:
|
||||
select {
|
||||
case <-tsCh:
|
||||
log.Println("prometheus remote-write buffer full, dropped measurements")
|
||||
default:
|
||||
tsCh <- staleMarkers
|
||||
}
|
||||
}
|
||||
case <-derpMapTicker.C:
|
||||
go func() {
|
||||
ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
|
||||
defer cancel()
|
||||
updatedDM, err := getDERPMap(ctx, *flagDERPMap)
|
||||
if err != nil {
|
||||
dmCh <- updatedDM
|
||||
}
|
||||
}()
|
||||
case err := <-httpErrCh:
|
||||
log.Printf("http server error: %v", err)
|
||||
shutdown()
|
||||
return
|
||||
case <-sigCh:
|
||||
shutdown()
|
||||
return
|
||||
}
|
||||
}
|
||||
}
|
||||
26
cmd/stunstamp/stunstamp_db_default.go
Normal file
26
cmd/stunstamp/stunstamp_db_default.go
Normal file
@@ -0,0 +1,26 @@
|
||||
// Copyright (c) Tailscale Inc & AUTHORS
|
||||
// SPDX-License-Identifier: BSD-3-Clause
|
||||
|
||||
//go:build !(windows && 386)
|
||||
|
||||
package main
|
||||
|
||||
import (
|
||||
"database/sql"
|
||||
|
||||
_ "modernc.org/sqlite"
|
||||
)
|
||||
|
||||
type db struct {
|
||||
*sql.DB
|
||||
}
|
||||
|
||||
func newDB(path string) (*db, error) {
|
||||
d, err := sql.Open("sqlite", *flagOut)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
return &db{
|
||||
DB: d,
|
||||
}, nil
|
||||
}
|
||||
17
cmd/stunstamp/stunstamp_db_windows_386.go
Normal file
17
cmd/stunstamp/stunstamp_db_windows_386.go
Normal file
@@ -0,0 +1,17 @@
|
||||
// Copyright (c) Tailscale Inc & AUTHORS
|
||||
// SPDX-License-Identifier: BSD-3-Clause
|
||||
|
||||
package main
|
||||
|
||||
import (
|
||||
"database/sql"
|
||||
"errors"
|
||||
)
|
||||
|
||||
type db struct {
|
||||
*sql.DB
|
||||
}
|
||||
|
||||
func newDB(path string) (*db, error) {
|
||||
return nil, errors.New("unsupported platform")
|
||||
}
|
||||
25
cmd/stunstamp/stunstamp_default.go
Normal file
25
cmd/stunstamp/stunstamp_default.go
Normal file
@@ -0,0 +1,25 @@
|
||||
// Copyright (c) Tailscale Inc & AUTHORS
|
||||
// SPDX-License-Identifier: BSD-3-Clause
|
||||
|
||||
//go:build !linux
|
||||
|
||||
package main
|
||||
|
||||
import (
|
||||
"errors"
|
||||
"io"
|
||||
"net"
|
||||
"time"
|
||||
)
|
||||
|
||||
func getConnKernelTimestamp() (io.ReadWriteCloser, error) {
|
||||
return nil, errors.New("unimplemented")
|
||||
}
|
||||
|
||||
func measureRTTKernel(conn io.ReadWriteCloser, dst *net.UDPAddr, req []byte) (resp []byte, rtt time.Duration, err error) {
|
||||
return nil, 0, errors.New("unimplemented")
|
||||
}
|
||||
|
||||
func supportsKernelTS() bool {
|
||||
return false
|
||||
}
|
||||
126
cmd/stunstamp/stunstamp_linux.go
Normal file
126
cmd/stunstamp/stunstamp_linux.go
Normal file
@@ -0,0 +1,126 @@
|
||||
// Copyright (c) Tailscale Inc & AUTHORS
|
||||
// SPDX-License-Identifier: BSD-3-Clause
|
||||
|
||||
package main
|
||||
|
||||
import (
|
||||
"bytes"
|
||||
"context"
|
||||
"encoding/binary"
|
||||
"errors"
|
||||
"fmt"
|
||||
"io"
|
||||
"net"
|
||||
"time"
|
||||
|
||||
"github.com/mdlayher/socket"
|
||||
"golang.org/x/sys/unix"
|
||||
)
|
||||
|
||||
const (
|
||||
flags = unix.SOF_TIMESTAMPING_TX_SOFTWARE | // tx timestamp generation in device driver
|
||||
unix.SOF_TIMESTAMPING_RX_SOFTWARE | // rx timestamp generation in the kernel
|
||||
unix.SOF_TIMESTAMPING_SOFTWARE // report software timestamps
|
||||
)
|
||||
|
||||
func getConnKernelTimestamp() (io.ReadWriteCloser, error) {
|
||||
sconn, err := socket.Socket(unix.AF_INET6, unix.SOCK_DGRAM, unix.IPPROTO_UDP, "udp", nil)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
sa := unix.SockaddrInet6{}
|
||||
err = sconn.Bind(&sa)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
err = sconn.SetsockoptInt(unix.SOL_SOCKET, unix.SO_TIMESTAMPING_NEW, flags)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
return sconn, nil
|
||||
}
|
||||
|
||||
func parseTimestampFromCmsgs(oob []byte) (time.Time, error) {
|
||||
msgs, err := unix.ParseSocketControlMessage(oob)
|
||||
if err != nil {
|
||||
return time.Time{}, fmt.Errorf("error parsing oob as cmsgs: %w", err)
|
||||
}
|
||||
for _, msg := range msgs {
|
||||
if msg.Header.Level == unix.SOL_SOCKET && msg.Header.Type == unix.SO_TIMESTAMPING_NEW && len(msg.Data) >= 16 {
|
||||
sec := int64(binary.NativeEndian.Uint64(msg.Data[:8]))
|
||||
ns := int64(binary.NativeEndian.Uint64(msg.Data[8:16]))
|
||||
return time.Unix(sec, ns), nil
|
||||
}
|
||||
}
|
||||
return time.Time{}, errors.New("failed to parse timestamp from cmsgs")
|
||||
}
|
||||
|
||||
func measureRTTKernel(conn io.ReadWriteCloser, dst *net.UDPAddr, req []byte) (resp []byte, rtt time.Duration, err error) {
|
||||
sconn, ok := conn.(*socket.Conn)
|
||||
if !ok {
|
||||
return nil, 0, fmt.Errorf("conn of unexpected type: %T", conn)
|
||||
}
|
||||
|
||||
var to unix.Sockaddr
|
||||
to4 := dst.IP.To4()
|
||||
if to4 != nil {
|
||||
to = &unix.SockaddrInet4{
|
||||
Port: 3478,
|
||||
}
|
||||
copy(to.(*unix.SockaddrInet4).Addr[:], to4)
|
||||
} else {
|
||||
to = &unix.SockaddrInet6{
|
||||
Port: 3478,
|
||||
}
|
||||
copy(to.(*unix.SockaddrInet6).Addr[:], dst.IP)
|
||||
}
|
||||
|
||||
err = sconn.Sendto(context.Background(), req, 0, to)
|
||||
if err != nil {
|
||||
return nil, 0, fmt.Errorf("sendto error: %v", err) // don't wrap
|
||||
}
|
||||
|
||||
txCtx, txCancel := context.WithTimeout(context.Background(), time.Second*2)
|
||||
defer txCancel()
|
||||
|
||||
buf := make([]byte, 1024)
|
||||
oob := make([]byte, 1024)
|
||||
var txAt time.Time
|
||||
|
||||
for {
|
||||
n, oobn, _, _, err := sconn.Recvmsg(txCtx, buf, oob, unix.MSG_ERRQUEUE)
|
||||
if err != nil {
|
||||
return nil, 0, fmt.Errorf("recvmsg (MSG_ERRQUEUE) error: %v", err) // don't wrap
|
||||
}
|
||||
|
||||
buf = buf[:n]
|
||||
if n < len(req) || !bytes.Equal(req, buf[len(buf)-len(req):]) {
|
||||
// Spin until we find the message we sent. We get the full packet
|
||||
// looped including eth header so match against the tail.
|
||||
continue
|
||||
}
|
||||
txAt, err = parseTimestampFromCmsgs(oob[:oobn])
|
||||
if err != nil {
|
||||
return nil, 0, fmt.Errorf("failed to get tx timestamp: %v", err) // don't wrap
|
||||
}
|
||||
break
|
||||
}
|
||||
|
||||
rxCtx, rxCancel := context.WithTimeout(context.Background(), time.Second*2)
|
||||
defer rxCancel()
|
||||
n, oobn, _, _, err := sconn.Recvmsg(rxCtx, buf, oob, 0)
|
||||
if err != nil {
|
||||
return nil, 0, fmt.Errorf("recvmsg error: %w", err) // wrap for timeout-related error unwrapping
|
||||
}
|
||||
|
||||
rxAt, err := parseTimestampFromCmsgs(oob[:oobn])
|
||||
if err != nil {
|
||||
return nil, 0, fmt.Errorf("failed to get rx timestamp: %v", err) // don't wrap
|
||||
}
|
||||
|
||||
return buf[:n], rxAt.Sub(txAt), nil
|
||||
}
|
||||
|
||||
func supportsKernelTS() bool {
|
||||
return true
|
||||
}
|
||||
Reference in New Issue
Block a user