ipn/ipnlocal: move Ping method from IPN bus to LocalBackend (HTTP)

Change-Id: I61759f1dae8d9d446353db54c8b1e13bfffb3287
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

ipn/backend.go

@@ -65,14 +65,13 @@ type Notify struct {
 	// For State InUseOtherUser, ErrMessage is not critical and just contains the details.
 	ErrMessage *string
 
-	LoginFinished *empty.Message       // non-nil when/if the login process succeeded
-	State         *State               // if non-nil, the new or current IPN state
-	Prefs         *Prefs               // if non-nil, the new or current preferences
-	NetMap        *netmap.NetworkMap   // if non-nil, the new or current netmap
-	Engine        *EngineStatus        // if non-nil, the new or urrent wireguard stats
-	BrowseToURL   *string              // if non-nil, UI should open a browser right now
-	BackendLogID  *string              // if non-nil, the public logtail ID used by backend
-	PingResult    *ipnstate.PingResult // if non-nil, a ping response arrived
+	LoginFinished *empty.Message     // non-nil when/if the login process succeeded
+	State         *State             // if non-nil, the new or current IPN state
+	Prefs         *Prefs             // if non-nil, the new or current preferences
+	NetMap        *netmap.NetworkMap // if non-nil, the new or current netmap
+	Engine        *EngineStatus      // if non-nil, the new or urrent wireguard stats
+	BrowseToURL   *string            // if non-nil, UI should open a browser right now
+	BackendLogID  *string            // if non-nil, the public logtail ID used by backend
 
 	// FilesWaiting if non-nil means that files are buffered in
 	// the Tailscale daemon and ready for local transfer to the
@@ -122,9 +121,6 @@ func (n Notify) String() string {
 	if n.BackendLogID != nil {
 		sb.WriteString("BackendLogID ")
 	}
-	if n.PingResult != nil {
-		fmt.Fprintf(&sb, "ping=%v ", *n.PingResult)
-	}
 	if n.FilesWaiting != nil {
 		sb.WriteString("FilesWaiting ")
 	}
@@ -245,8 +241,4 @@ type Backend interface {
 	// counts. Connection events are emitted automatically without
 	// polling.
 	RequestEngineStatus()
-	// Ping attempts to start connecting to the given IP and sends a Notify
-	// with its PingResult. If the host is down, there might never
-	// be a PingResult sent. The cmd/tailscale CLI client adds a timeout.
-	Ping(ip string, pingType tailcfg.PingType)
 }

ipn/fake_test.go

@@ -5,7 +5,6 @@
 package ipn
 
 import (
-	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/netmap"
 )
@@ -99,9 +98,3 @@ func (b *FakeBackend) RequestEngineStatus() {
 		b.notify(Notify{Engine: &EngineStatus{}})
 	}
 }
-
-func (b *FakeBackend) Ping(ip string, pingType tailcfg.PingType) {
-	if b.notify != nil {
-		b.notify(Notify{PingResult: &ipnstate.PingResult{}})
-	}
-}

ipn/ipnlocal/local.go

@@ -1698,15 +1698,20 @@ func (b *LocalBackend) StartLoginInteractive() {
 	}
 }
 
-func (b *LocalBackend) Ping(ipStr string, pingType tailcfg.PingType) {
-	ip, err := netaddr.ParseIP(ipStr)
-	if err != nil {
-		b.logf("ignoring Ping request to invalid IP %q", ipStr)
-		return
-	}
+func (b *LocalBackend) Ping(ctx context.Context, ip netaddr.IP, pingType tailcfg.PingType) (*ipnstate.PingResult, error) {
+	ch := make(chan *ipnstate.PingResult, 1)
 	b.e.Ping(ip, pingType, func(pr *ipnstate.PingResult) {
-		b.send(ipn.Notify{PingResult: pr})
+		select {
+		case ch <- pr:
+		default:
+		}
 	})
+	select {
+	case pr := <-ch:
+		return pr, nil
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	}
 }
 
 // parseWgStatusLocked returns an EngineStatus based on s.

ipn/localapi/localapi.go

@@ -111,6 +111,8 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		h.serveLogout(w, r)
 	case "/localapi/v0/prefs":
 		h.servePrefs(w, r)
+	case "/localapi/v0/ping":
+		h.servePing(w, r)
 	case "/localapi/v0/check-prefs":
 		h.serveCheckPrefs(w, r)
 	case "/localapi/v0/check-ip-forwarding":
@@ -625,6 +627,36 @@ func (h *Handler) serveSetExpirySooner(w http.ResponseWriter, r *http.Request) {
 	io.WriteString(w, "done\n")
 }
 
+func (h *Handler) servePing(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+	if r.Method != "POST" {
+		http.Error(w, "want POST", 400)
+		return
+	}
+	ipStr := r.FormValue("ip")
+	if ipStr == "" {
+		http.Error(w, "missing 'ip' parameter", 400)
+		return
+	}
+	ip, err := netaddr.ParseIP(ipStr)
+	if err != nil {
+		http.Error(w, "invalid IP", 400)
+		return
+	}
+	pingTypeStr := r.FormValue("type")
+	if ipStr == "" {
+		http.Error(w, "missing 'type' parameter", 400)
+		return
+	}
+	res, err := h.b.Ping(ctx, ip, tailcfg.PingType(pingTypeStr))
+	if err != nil {
+		writeErrorJSON(w, err)
+		return
+	}
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(res)
+}
+
 func (h *Handler) serveDial(w http.ResponseWriter, r *http.Request) {
 	if r.Method != "POST" {
 		http.Error(w, "POST required", http.StatusMethodNotAllowed)

ipn/message.go

@@ -51,11 +51,6 @@ type SetPrefsArgs struct {
 	New *Prefs
 }
 
-type PingArgs struct {
-	IP   string
-	Type tailcfg.PingType
-}
-
 // Command is a command message that is JSON encoded and sent by a
 // frontend to a backend.
 type Command struct {
@@ -78,7 +73,6 @@ type Command struct {
 	SetPrefs              *SetPrefsArgs
 	RequestEngineStatus   *NoArgs
 	RequestStatus         *NoArgs
-	Ping                  *PingArgs
 }
 
 type BackendServer struct {
@@ -170,9 +164,6 @@ func (bs *BackendServer) GotCommand(ctx context.Context, cmd *Command) error {
 	if c := cmd.RequestEngineStatus; c != nil {
 		bs.b.RequestEngineStatus()
 		return nil
-	} else if c := cmd.Ping; c != nil {
-		bs.b.Ping(c.IP, tailcfg.PingType(c.Type))
-		return nil
 	}
 
 	if IsReadonlyContext(ctx) {
@@ -311,13 +302,6 @@ func (bc *BackendClient) RequestStatus() {
 	bc.send(Command{AllowVersionSkew: true, RequestStatus: &NoArgs{}})
 }
 
-func (bc *BackendClient) Ping(ip string, pingType tailcfg.PingType) {
-	bc.send(Command{Ping: &PingArgs{
-		IP:   ip,
-		Type: pingType,
-	}})
-}
-
 // MaxMessageSize is the maximum message size, in bytes.
 const MaxMessageSize = 10 << 20