From 4007601f734fb32b65314b90972d167cda14a49c Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@tailscale.com>
Date: Mon, 6 Jun 2022 13:07:14 -0700
Subject: [PATCH] cmd/controlclient: wire up PingRequest peerapi pings too

Updates tailscale/corp#754

Change-Id: I61ac3fc44783b54bd02455bcb0baf19159b7a9d2
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
---
 control/controlclient/direct.go | 26 +++++++++++++++-----------
 ipn/ipnlocal/local.go           |  2 +-
 2 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/control/controlclient/direct.go b/control/controlclient/direct.go
index 7d9671dfb..bff285865 100644
--- a/control/controlclient/direct.go
+++ b/control/controlclient/direct.go
@@ -124,11 +124,10 @@ type Options struct {
 	Pinger Pinger
 }
 
-// Pinger is a subset of the wgengine.Engine interface, containing just the Ping method.
+// Pinger is the LocalBackend.Ping method.
 type Pinger interface {
-	// Ping is a request to start a ping with the peer handling the given IP and
-	// then call cb with its ping latency & method.
-	Ping(ip netaddr.IP, pingType tailcfg.PingType, cb func(*ipnstate.PingResult))
+	// Ping is a request to do a ping with the peer handling the given IP.
+	Ping(ctx context.Context, ip netaddr.IP, pingType tailcfg.PingType) (*ipnstate.PingResult, error)
 }
 
 type Decompressor interface {
@@ -1208,10 +1207,8 @@ func answerPing(logf logger.Logf, c *http.Client, pr *tailcfg.PingRequest, pinge
 	}
 	for _, t := range strings.Split(pr.Types, ",") {
 		switch pt := tailcfg.PingType(t); pt {
-		case tailcfg.PingTSMP, tailcfg.PingDisco, tailcfg.PingICMP:
+		case tailcfg.PingTSMP, tailcfg.PingDisco, tailcfg.PingICMP, tailcfg.PingPeerAPI:
 			go doPingerPing(logf, c, pr, pinger, pt)
-		// TODO(tailscale/corp#754)
-		// case "peerapi":
 		default:
 			logf("unsupported ping request type: %q", t)
 		}
@@ -1417,10 +1414,17 @@ func doPingerPing(logf logger.Logf, c *http.Client, pr *tailcfg.PingRequest, pin
 		return
 	}
 	start := time.Now()
-	pinger.Ping(pr.IP, pingType, func(res *ipnstate.PingResult) {
-		// Currently does not check for error since we just return if it fails.
-		postPingResult(start, logf, c, pr, res.ToPingResponse(pingType))
-	})
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	res, err := pinger.Ping(ctx, pr.IP, pingType)
+	if err != nil {
+		d := time.Since(start).Round(time.Millisecond)
+		logf("doPingerPing: ping error of type %q to %v after %v: %v", pingType, pr.IP, d, err)
+		return
+	}
+	postPingResult(start, logf, c, pr, res.ToPingResponse(pingType))
 }
 
 func postPingResult(start time.Time, logf logger.Logf, c *http.Client, pr *tailcfg.PingRequest, res *tailcfg.PingResponse) error {
diff --git a/ipn/ipnlocal/local.go b/ipn/ipnlocal/local.go
index 4fd5c60e6..334f9a407 100644
--- a/ipn/ipnlocal/local.go
+++ b/ipn/ipnlocal/local.go
@@ -1035,7 +1035,7 @@ func (b *LocalBackend) Start(opts ipn.Options) error {
 		DiscoPublicKey:       discoPublic,
 		DebugFlags:           debugFlags,
 		LinkMonitor:          b.e.GetLinkMonitor(),
-		Pinger:               b.e,
+		Pinger:               b,
 		PopBrowserURL:        b.tellClientToBrowseToURL,
 		Dialer:               b.Dialer(),