tsnet: set Hostinfo.Package to "tsnet" on use

Fixes #4256

Change-Id: I11276596c3724bead1e0aa1f2e57ba75cef3b6be
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

hostinfo/hostinfo.go

@@ -107,8 +107,9 @@ func SetDeviceModel(model string) { deviceModelAtomic.Store(model) }
 func SetOSVersion(v string) { osVersionAtomic.Store(v) }
 
 // SetPackage sets the packaging type for the app.
-// This is currently (2021-10-05) only used by Android,
-// set to "nogoogle" for the F-Droid build.
+//
+// As of 2022-03-25, this is used by Android ("nogoogle" for the
+// F-Droid build) and tsnet (set to "tsnet").
 func SetPackage(v string) { packagingType.Store(v) }
 
 func deviceModel() string {

tsnet/tsnet.go

@@ -23,6 +23,7 @@ import (
 	"tailscale.com/client/tailscale"
 	"tailscale.com/control/controlclient"
 	"tailscale.com/envknob"
+	"tailscale.com/hostinfo"
 	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnlocal"
 	"tailscale.com/ipn/localapi"
@@ -92,6 +93,7 @@ func (s *Server) Dial(ctx context.Context, network, address string) (net.Conn, e
 // Start connects the server to the tailnet.
 // Optional: any calls to Dial/Listen will also call Start.
 func (s *Server) Start() error {
+	hostinfo.SetPackage("tsnet")
 	s.initOnce.Do(s.doInit)
 	return s.initErr
 }
@@ -116,7 +118,6 @@ func (s *Server) Close() error {
 }
 
 func (s *Server) doInit() {
-
 	s.shutdownCtx, s.shutdownCancel = context.WithCancel(context.Background())
 	if err := s.start(); err != nil {
 		s.initErr = fmt.Errorf("tsnet: %w", err)