Move Linux client & common packages into a public repo.

derp/doc.go

@@ -0,0 +1,13 @@
+// Copyright (c) 2020 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 derp implements DERP, the Detour Encrypted Routing Protocol.
+//
+// DERP routes packets to clients using curve25519 keys as addresses.
+//
+// DERP is used by Tailscale nodes to proxy encrypted WireGuard
+// packets through the Tailscale cloud servers when a direct path
+// cannot be found or opened. DERP is a last resort. Both sides
+// between very aggressive NATs, firewalls, no IPv6, etc? Well, DERP.
+package derp