tailscale: Add runtime exit node API

experimental/libbox/command_client.go

@@ -780,6 +780,19 @@ func (c *CommandClient) SubscribeTailscaleStatus(handler TailscaleStatusHandler)
 	}
 }
 
+func (c *CommandClient) SetTailscaleExitNode(endpointTag string, stableID string) error {
+	_, err := callWithResult(c, func(client daemon.StartedServiceClient) (*emptypb.Empty, error) {
+		return client.SetTailscaleExitNode(context.Background(), &daemon.SetTailscaleExitNodeRequest{
+			EndpointTag: endpointTag,
+			StableID:    stableID,
+		})
+	})
+	if err != nil {
+		return E.Cause(err, "set tailscale exit node")
+	}
+	return nil
+}
+
 func (c *CommandClient) StartTailscalePing(endpointTag string, peerIP string, handler TailscalePingHandler) error {
 	client, err := c.getClientForCall()
 	if err != nil {

experimental/libbox/command_types_tailscale.go

@@ -22,6 +22,7 @@ type TailscaleEndpointStatus struct {
 	NetworkName    string
 	MagicDNSSuffix string
 	Self           *TailscalePeer
+	ExitNode       *TailscalePeer
 	userGroups     []*TailscaleUserGroup
 }
 
@@ -52,6 +53,7 @@ type TailscalePeerIterator interface {
 }
 
 type TailscalePeer struct {
+	StableID       string
 	HostName       string
 	DNSName        string
 	OS             string
@@ -98,6 +100,9 @@ func tailscaleEndpointStatusFromGRPC(status *daemon.TailscaleEndpointStatus) *Ta
 	if status.Self != nil {
 		result.Self = tailscalePeerFromGRPC(status.Self)
 	}
+	if status.ExitNode != nil {
+		result.ExitNode = tailscalePeerFromGRPC(status.ExitNode)
+	}
 	return result
 }
 
@@ -117,6 +122,7 @@ func tailscaleUserGroupFromGRPC(group *daemon.TailscaleUserGroup) *TailscaleUser
 
 func tailscalePeerFromGRPC(peer *daemon.TailscalePeer) *TailscalePeer {
 	return &TailscalePeer{
+		StableID:       peer.StableID,
 		HostName:       peer.HostName,
 		DNSName:        peer.DnsName,
 		OS:             peer.Os,