control/controlclient,tailcfg: propagate registration errors to the frontend

Signed-off-by: Maisem Ali <maisem@tailscale.com>

control/controlclient/auto.go

@@ -281,7 +281,6 @@ func (c *Auto) authRoutine() {
 
 		report := func(err error, msg string) {
 			c.logf("[v1] %s: %v", msg, err)
-			err = fmt.Errorf("%s: %v", msg, err)
 			// don't send status updates for context errors,
 			// since context cancelation is always on purpose.
 			if ctx.Err() == nil {
@@ -431,7 +430,7 @@ func (c *Auto) mapRoutine() {
 
 		report := func(err error, msg string) {
 			c.logf("[v1] %s: %v", msg, err)
-			err = fmt.Errorf("%s: %v", msg, err)
+			err = fmt.Errorf("%s: %w", msg, err)
 			// don't send status updates for context errors,
 			// since context cancelation is always on purpose.
 			if ctx.Err() == nil {
@@ -599,9 +598,7 @@ func (c *Auto) sendStatus(who string, err error, url string, nm *netmap.NetworkM
 		NetMap:         nm,
 		Hostinfo:       hi,
 		State:          state,
-	}
-	if err != nil {
-		new.Err = err.Error()
+		Err:            err,
 	}
 	if statusFunc != nil {
 		statusFunc(new)

control/controlclient/direct.go

@@ -435,6 +435,9 @@ func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, new
 	c.logf("RegisterReq: got response; nodeKeyExpired=%v, machineAuthorized=%v; authURL=%v",
 		resp.NodeKeyExpired, resp.MachineAuthorized, resp.AuthURL != "")
 
+	if resp.Error != "" {
+		return false, "", errors.New(resp.Error)
+	}
 	if resp.NodeKeyExpired {
 		if regen {
 			return true, "", fmt.Errorf("weird: regen=true but server says NodeKeyExpired: %v", request.NodeKey)

control/controlclient/status.go

@@ -67,7 +67,7 @@ type Status struct {
 	_              structs.Incomparable
 	LoginFinished  *empty.Message // nonempty when login finishes
 	LogoutFinished *empty.Message // nonempty when logout finishes
-	Err            string
+	Err            error
 	URL            string             // interactive URL to visit to finish logging in
 	NetMap         *netmap.NetworkMap // server-pushed configuration