wgengine/magicsock: add HTML debug handler to see magicsock state

Change-Id: Ibc46f4e9651e1c86ec6f5d139f5e9bdc7a488415 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
4 years ago · ae319b4636
parent c7f5bc0f69
commit ae319b4636
3 changed files with 228 additions and 1 deletions
--- a/cmd/tailscaled/tailscaled.go
+++ b/cmd/tailscaled/tailscaled.go
@ -295,7 +295,6 @@ func run() error {
 	var debugMux *http.ServeMux
 	if args.debug != "" {
 		debugMux = newDebugMux()
-		go runDebugServer(debugMux, args.debug)
 	}

 	linkMon, err := monitor.New(logf)
@ -314,6 +313,14 @@ func run() error {
 	if _, ok := e.(wgengine.ResolvingEngine).GetResolver(); !ok {
 		panic("internal error: exit node resolver not wired up")
 	}
+	if debugMux != nil {
+		if ig, ok := e.(wgengine.InternalsGetter); ok {
+			if _, mc, ok := ig.GetInternals(); ok {
+				debugMux.HandleFunc("/debug/magicsock", mc.ServeHTTPDebug)
+			}
+		}
+		go runDebugServer(debugMux, args.debug)
+	}

 	ns, err := newNetstack(logf, dialer, e)
 	if err != nil {
--- a/ipn/ipnlocal/peerapi.go
+++ b/ipn/ipnlocal/peerapi.go
@ -553,6 +553,9 @@ func (h *peerAPIHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	case "/v0/metrics":
 		h.handleServeMetrics(w, r)
 		return
+	case "/v0/magicsock":
+		h.handleServeMagicsock(w, r)
+		return
 	}
 	who := h.peerUser.DisplayName
 	fmt.Fprintf(w, `<html>
@ -781,6 +784,21 @@ func (h *peerAPIHandler) handleServeEnv(w http.ResponseWriter, r *http.Request)
 	json.NewEncoder(w).Encode(data)
 }

+func (h *peerAPIHandler) handleServeMagicsock(w http.ResponseWriter, r *http.Request) {
+	if !h.isSelf {
+		http.Error(w, "not owner", http.StatusForbidden)
+		return
+	}
+	eng := h.ps.b.e
+	if ig, ok := eng.(wgengine.InternalsGetter); ok {
+		if _, mc, ok := ig.GetInternals(); ok {
+			mc.ServeHTTPDebug(w, r)
+			return
+		}
+	}
+	http.Error(w, "miswired", 500)
+}
+
 func (h *peerAPIHandler) handleServeMetrics(w http.ResponseWriter, r *http.Request) {
 	if !h.isSelf {
 		http.Error(w, "not owner", http.StatusForbidden)
--- a/wgengine/magicsock/debughttp.go
+++ b/wgengine/magicsock/debughttp.go
@ -0,0 +1,202 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package magicsock
+
+import (
+	"fmt"
+	"html"
+	"io"
+	"net/http"
+	"sort"
+	"strings"
+	"time"
+
+	"inet.af/netaddr"
+	"tailscale.com/tailcfg"
+	"tailscale.com/tstime/mono"
+	"tailscale.com/types/key"
+)
+
+// ServeHTTPDebug serves an HTML representation of the innards of c for debugging.
+//
+// It's accessible either from tailscaled's debug port (at
+// /debug/magicsock) or via peerapi to a peer that's owned by the same
+// user (so they can e.g. inspect their phones).
+func (c *Conn) ServeHTTPDebug(w http.ResponseWriter, r *http.Request) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	now := time.Now()
+
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	fmt.Fprintf(w, "<h1>magicsock</h1>")
+
+	fmt.Fprintf(w, "<h2 id=derp><a href=#derp>#</a> DERP</h2><ul>")
+	if c.derpMap != nil {
+		type D struct {
+			regionID   int
+			lastWrite  time.Time
+			createTime time.Time
+		}
+		ent := make([]D, 0, len(c.activeDerp))
+		for rid, ad := range c.activeDerp {
+			ent = append(ent, D{
+				regionID:   rid,
+				lastWrite:  *ad.lastWrite,
+				createTime: ad.createTime,
+			})
+		}
+		sort.Slice(ent, func(i, j int) bool {
+			return ent[i].regionID < ent[j].regionID
+		})
+		for _, e := range ent {
+			r, ok := c.derpMap.Regions[e.regionID]
+			if !ok {
+				continue
+			}
+			home := ""
+			if e.regionID == c.myDerp {
+				home = "🏠"
+			}
+			fmt.Fprintf(w, "<li>%s %d - %v: created %v ago, write %v ago</li>\n",
+				home, e.regionID, html.EscapeString(r.RegionCode),
+				now.Sub(e.createTime).Round(time.Second),
+				now.Sub(e.lastWrite).Round(time.Second),
+			)
+		}
+
+	}
+	fmt.Fprintf(w, "</ul>\n")
+
+	fmt.Fprintf(w, "<h2 id=ipport><a href=#ipport>#</a> ip:port to endpoint</h2><ul>")
+	{
+		type kv struct {
+			ipp netaddr.IPPort
+			pi  *peerInfo
+		}
+		ent := make([]kv, 0, len(c.peerMap.byIPPort))
+		for k, v := range c.peerMap.byIPPort {
+			ent = append(ent, kv{k, v})
+		}
+		sort.Slice(ent, func(i, j int) bool { return ipPortLess(ent[i].ipp, ent[j].ipp) })
+		for _, e := range ent {
+			ep := e.pi.ep
+			shortStr := ep.publicKey.ShortString()
+			fmt.Fprintf(w, "<li>%v: <a href='#%v'>%v</a></li>\n", e.ipp, strings.Trim(shortStr, "[]"), shortStr)
+		}
+
+	}
+	fmt.Fprintf(w, "</ul>\n")
+
+	fmt.Fprintf(w, "<h2 id=bykey><a href=#bykey>#</a> endpoints by key</h2>")
+	{
+		type kv struct {
+			pub key.NodePublic
+			pi  *peerInfo
+		}
+		ent := make([]kv, 0, len(c.peerMap.byNodeKey))
+		for k, v := range c.peerMap.byNodeKey {
+			ent = append(ent, kv{k, v})
+		}
+		sort.Slice(ent, func(i, j int) bool { return ent[i].pub.Less(ent[j].pub) })
+
+		peers := map[key.NodePublic]*tailcfg.Node{}
+		if c.netMap != nil {
+			for _, p := range c.netMap.Peers {
+				peers[p.Key] = p
+			}
+		}
+
+		for _, e := range ent {
+			ep := e.pi.ep
+			shortStr := e.pub.ShortString()
+			name := peerDebugName(peers[e.pub])
+			fmt.Fprintf(w, "<h3 id=%v><a href='#%v'>%v</a> - %s</h3>\n",
+				strings.Trim(shortStr, "[]"),
+				strings.Trim(shortStr, "[]"),
+				shortStr,
+				html.EscapeString(name))
+			printEndpointHTML(w, ep)
+		}
+
+	}
+}
+
+func printEndpointHTML(w io.Writer, ep *endpoint) {
+	lastRecv := ep.lastRecv.LoadAtomic()
+
+	ep.mu.Lock()
+	defer ep.mu.Unlock()
+	if ep.lastSend == 0 && lastRecv == 0 {
+		return // no activity ever
+	}
+
+	now := time.Now()
+	mnow := mono.Now()
+	fmtMono := func(m mono.Time) string {
+		if m == 0 {
+			return "-"
+		}
+		return mnow.Sub(m).Round(time.Millisecond).String()
+	}
+
+	fmt.Fprintf(w, "<p>Best: <b>%+v</b>, %v ago (for %v)</p>\n", ep.bestAddr, fmtMono(ep.bestAddrAt), ep.trustBestAddrUntil.Sub(mnow).Round(time.Millisecond))
+	fmt.Fprintf(w, "<p>heartbeating: %v</p>\n", ep.heartBeatTimer != nil)
+	fmt.Fprintf(w, "<p>lastSend: %v ago</p>\n", fmtMono(ep.lastSend))
+	fmt.Fprintf(w, "<p>lastFullPing: %v ago</p>\n", fmtMono(ep.lastFullPing))
+
+	eps := make([]netaddr.IPPort, 0, len(ep.endpointState))
+	for ipp := range ep.endpointState {
+		eps = append(eps, ipp)
+	}
+	sort.Slice(eps, func(i, j int) bool { return ipPortLess(eps[i], eps[j]) })
+	io.WriteString(w, "<p>Endpoints:</p><ul>")
+	for _, ipp := range eps {
+		s := ep.endpointState[ipp]
+		if ipp == ep.bestAddr.IPPort {
+			fmt.Fprintf(w, "<li><b>%s</b>: (best)<ul>", ipp)
+		} else {
+			fmt.Fprintf(w, "<li>%s: ...<ul>", ipp)
+		}
+		fmt.Fprintf(w, "<li>lastPing: %v ago</li>\n", fmtMono(s.lastPing))
+		if s.lastGotPing.IsZero() {
+			fmt.Fprintf(w, "<li>disco-learned-at: -</li>\n")
+		} else {
+			fmt.Fprintf(w, "<li>disco-learned-at: %v ago</li>\n", now.Sub(s.lastGotPing).Round(time.Second))
+		}
+		fmt.Fprintf(w, "<li>callMeMaybeTime: %v</li>\n", s.callMeMaybeTime)
+		for i := range s.recentPongs {
+			if i == 5 {
+				break
+			}
+			pos := (int(s.recentPong) - i) % len(s.recentPongs)
+			pr := s.recentPongs[pos]
+			fmt.Fprintf(w, "<li>pong %v ago: in %v, from %v src %v</li>\n",
+				fmtMono(pr.pongAt), pr.latency.Round(time.Millisecond/10),
+				pr.from, pr.pongSrc)
+		}
+		fmt.Fprintf(w, "</ul></li>\n")
+	}
+	io.WriteString(w, "</ul>")
+
+}
+
+func peerDebugName(p *tailcfg.Node) string {
+	if p == nil {
+		return ""
+	}
+	n := p.Name
+	if i := strings.Index(n, "."); i != -1 {
+		return n[:i]
+	}
+	return p.Hostinfo.Hostname
+}
+
+func ipPortLess(a, b netaddr.IPPort) bool {
+	if v := a.IP().Compare(b.IP()); v != 0 {
+		return v < 0
+	}
+	return a.Port() < b.Port()
+}