cmd/tailscale: make ping --until-direct require direct connection to exit 0

If --until-direct is set, the goal is to make a direct connection.
If we failed at that, say so, and exit with an error.

RELNOTE=tailscale ping --until-direct (the default) now exits with
a non-zero exit code if no direct connection was established.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/cmd/tailscale/cli/ping.go b/cmd/tailscale/cli/ping.go
index 3f08cc138..25470aa69 100644
--- a/cmd/tailscale/cli/ping.go
+++ b/cmd/tailscale/cli/ping.go
@@ -139,6 +139,9 @@ func runPing(ctx context.Context, args []string) error {
 			if !anyPong {
 				return errors.New("no reply")
 			}
+			if pingArgs.untilDirect {
+				return errors.New("direct connection not established")
+			}
 			return nil
 		}
 	}