ipn/ipnlocal: extract ping implementation into its own file

There’s enough code to pull this out into its own ping.go file, since
local.go contains a lot of stuff.

The next commit will add a Pinger interface to this file, so I am
breaking out this refactor to make identifying the changes and
reviewing the actual patch easier.

Signed-off-by: Simon Law <sfllaw@tailscale.com>

ipn/ipnlocal/local.go

@@ -3700,81 +3700,6 @@ func (b *LocalBackend) StartLoginInteractiveAs(ctx context.Context, user ipnauth
 	return nil
 }
 
-func (b *LocalBackend) Ping(ctx context.Context, ip netip.Addr, pingType tailcfg.PingType, size int) (*ipnstate.PingResult, error) {
-	if pingType == tailcfg.PingPeerAPI {
-		t0 := b.clock.Now()
-		node, base, err := b.pingPeerAPI(ctx, ip)
-		if err != nil && ctx.Err() != nil {
-			return nil, ctx.Err()
-		}
-		d := b.clock.Since(t0)
-		pr := &ipnstate.PingResult{
-			IP:             ip.String(),
-			NodeIP:         ip.String(),
-			LatencySeconds: d.Seconds(),
-			PeerAPIURL:     base,
-		}
-		if err != nil {
-			pr.Err = err.Error()
-		}
-		if node.Valid() {
-			pr.NodeName = node.Name()
-		}
-		return pr, nil
-	}
-	ch := make(chan *ipnstate.PingResult, 1)
-	b.e.Ping(ip, pingType, size, func(pr *ipnstate.PingResult) {
-		select {
-		case ch <- pr:
-		default:
-		}
-	})
-	select {
-	case pr := <-ch:
-		return pr, nil
-	case <-ctx.Done():
-		return nil, ctx.Err()
-	}
-}
-
-func (b *LocalBackend) pingPeerAPI(ctx context.Context, ip netip.Addr) (peer tailcfg.NodeView, peerBase string, err error) {
-	if !buildfeatures.HasPeerAPIClient {
-		return peer, peerBase, feature.ErrUnavailable
-	}
-	var zero tailcfg.NodeView
-	ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
-	defer cancel()
-	nm := b.NetMap()
-	if nm == nil {
-		return zero, "", errors.New("no netmap")
-	}
-	peer, ok := nm.PeerByTailscaleIP(ip)
-	if !ok {
-		return zero, "", fmt.Errorf("no peer found with Tailscale IP %v", ip)
-	}
-	if peer.Expired() {
-		return zero, "", errors.New("peer's node key has expired")
-	}
-	base := peerAPIBase(nm, peer)
-	if base == "" {
-		return zero, "", fmt.Errorf("no PeerAPI base found for peer %v (%v)", peer.ID(), ip)
-	}
-	outReq, err := http.NewRequestWithContext(ctx, "HEAD", base, nil)
-	if err != nil {
-		return zero, "", err
-	}
-	tr := b.Dialer().PeerAPITransport()
-	res, err := tr.RoundTrip(outReq)
-	if err != nil {
-		return zero, "", err
-	}
-	defer res.Body.Close() // but unnecessary on HEAD responses
-	if res.StatusCode != http.StatusOK {
-		return zero, "", fmt.Errorf("HTTP status %v", res.Status)
-	}
-	return peer, base, nil
-}
-
 // parseWgStatusLocked returns an EngineStatus based on s.
 //
 // b.mu must be held; mostly because the caller is about to anyway, and doing so

ipn/ipnlocal/ping.go

@@ -0,0 +1,93 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package ipnlocal
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/netip"
+	"time"
+
+	"tailscale.com/feature"
+	"tailscale.com/feature/buildfeatures"
+	"tailscale.com/ipn/ipnstate"
+	"tailscale.com/tailcfg"
+)
+
+func (b *LocalBackend) Ping(ctx context.Context, ip netip.Addr, pingType tailcfg.PingType, size int) (*ipnstate.PingResult, error) {
+	if pingType == tailcfg.PingPeerAPI {
+		t0 := b.clock.Now()
+		node, base, err := b.pingPeerAPI(ctx, ip)
+		if err != nil && ctx.Err() != nil {
+			return nil, ctx.Err()
+		}
+		d := b.clock.Since(t0)
+		pr := &ipnstate.PingResult{
+			IP:             ip.String(),
+			NodeIP:         ip.String(),
+			LatencySeconds: d.Seconds(),
+			PeerAPIURL:     base,
+		}
+		if err != nil {
+			pr.Err = err.Error()
+		}
+		if node.Valid() {
+			pr.NodeName = node.Name()
+		}
+		return pr, nil
+	}
+	ch := make(chan *ipnstate.PingResult, 1)
+	b.e.Ping(ip, pingType, size, func(pr *ipnstate.PingResult) {
+		select {
+		case ch <- pr:
+		default:
+		}
+	})
+	select {
+	case pr := <-ch:
+		return pr, nil
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	}
+}
+
+func (b *LocalBackend) pingPeerAPI(ctx context.Context, ip netip.Addr) (peer tailcfg.NodeView, peerBase string, err error) {
+	if !buildfeatures.HasPeerAPIClient {
+		return peer, peerBase, feature.ErrUnavailable
+	}
+	var zero tailcfg.NodeView
+	ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
+	defer cancel()
+	nm := b.NetMap()
+	if nm == nil {
+		return zero, "", errors.New("no netmap")
+	}
+	peer, ok := nm.PeerByTailscaleIP(ip)
+	if !ok {
+		return zero, "", fmt.Errorf("no peer found with Tailscale IP %v", ip)
+	}
+	if peer.Expired() {
+		return zero, "", errors.New("peer's node key has expired")
+	}
+	base := peerAPIBase(nm, peer)
+	if base == "" {
+		return zero, "", fmt.Errorf("no PeerAPI base found for peer %v (%v)", peer.ID(), ip)
+	}
+	outReq, err := http.NewRequestWithContext(ctx, "HEAD", base, nil)
+	if err != nil {
+		return zero, "", err
+	}
+	tr := b.Dialer().PeerAPITransport()
+	res, err := tr.RoundTrip(outReq)
+	if err != nil {
+		return zero, "", err
+	}
+	defer res.Body.Close() // but unnecessary on HEAD responses
+	if res.StatusCode != http.StatusOK {
+		return zero, "", fmt.Errorf("HTTP status %v", res.Status)
+	}
+	return peer, base, nil
+}