From 79cf550823b9b3c7470387f4ffad9ec4f6c1f949 Mon Sep 17 00:00:00 2001
From: Will Norris <will@tailscale.com>
Date: Thu, 25 Aug 2022 16:39:14 -0700
Subject: [PATCH] cmd/tailscale: add licenses subcommand

Signed-off-by: Will Norris <will@tailscale.com>
---
 cmd/tailscale/cli/cli.go      |  1 +
 cmd/tailscale/cli/licenses.go | 29 +++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 cmd/tailscale/cli/licenses.go

diff --git a/cmd/tailscale/cli/cli.go b/cmd/tailscale/cli/cli.go
index 4a73c4ce6..00fc24296 100644
--- a/cmd/tailscale/cli/cli.go
+++ b/cmd/tailscale/cli/cli.go
@@ -170,6 +170,7 @@ change in the future.
 			bugReportCmd,
 			certCmd,
 			netlockCmd,
+			licensesCmd,
 		},
 		FlagSet:   rootfs,
 		Exec:      func(context.Context, []string) error { return flag.ErrHelp },
diff --git a/cmd/tailscale/cli/licenses.go b/cmd/tailscale/cli/licenses.go
new file mode 100644
index 000000000..2c746d2c0
--- /dev/null
+++ b/cmd/tailscale/cli/licenses.go
@@ -0,0 +1,29 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cli
+
+import (
+	"context"
+
+	"github.com/peterbourgon/ff/v3/ffcli"
+)
+
+var licensesCmd = &ffcli.Command{
+	Name:       "licenses",
+	ShortUsage: "licenses",
+	ShortHelp:  "Get open source license information",
+	LongHelp:   "Get open source license information",
+	Exec:       runLicenses,
+}
+
+func runLicenses(ctx context.Context, args []string) error {
+	outln(`
+Tailscale wouldn't be possible without the contributions of thousands of open
+source developers. To see the open source packages included in Tailscale and
+their respective license information, visit:
+
+    https://tailscale.com/licenses/tailscale`)
+	return nil
+}