cmd/tailscale: add missing set flags for linux

We were missing `snat-subnet-routes`, `stateful-filtering`
and `netfilter-mode`. Add those to set too.

Fixes #12061

Signed-off-by: Maisem Ali <maisem@tailscale.com>

cmd/tailscale/cli/set.go

@@ -58,6 +58,9 @@ type setArgsT struct {
 	updateCheck            bool
 	updateApply            bool
 	postureChecking        bool
+	snat                   bool
+	statefulFiltering      bool
+	netfilterMode          string
 }
 
 func newSetFlagSet(goos string, setArgs *setArgsT) *flag.FlagSet {
@@ -98,6 +101,10 @@ func newSetFlagSet(goos string, setArgs *setArgsT) *flag.FlagSet {
 		setf.StringVar(&setArgs.opUser, "operator", "", "Unix username to allow to operate on tailscaled without sudo")
 	}
 	switch goos {
+	case "linux":
+		setf.BoolVar(&setArgs.snat, "snat-subnet-routes", true, "source NAT traffic to local routes advertised with --advertise-routes")
+		setf.BoolVar(&setArgs.statefulFiltering, "stateful-filtering", true, "apply stateful filtering to forwarded packets (subnet routers, exit nodes, etc.)")
+		setf.StringVar(&setArgs.netfilterMode, "netfilter-mode", defaultNetfilterMode(), "netfilter mode (one of on, nodivert, off)")
 	case "windows":
 		setf.BoolVar(&setArgs.forceDaemon, "unattended", false, "run in \"Unattended Mode\" where Tailscale keeps running even after the current GUI user logs out (Windows-only)")
 	}
@@ -121,6 +128,9 @@ func runSet(ctx context.Context, args []string) (retErr error) {
 		return err
 	}
 
+	// Note that even though we set the values here regardless of whether the
+	// user passed the flag, the value is only used if the user passed the flag.
+	// See updateMaskedPrefsFromUpOrSetFlag.
 	maskedPrefs := &ipn.MaskedPrefs{
 		Prefs: ipn.Prefs{
 			ProfileName:            setArgs.profileName,
@@ -132,6 +142,7 @@ func runSet(ctx context.Context, args []string) (retErr error) {
 			RunWebClient:           setArgs.runWebClient,
 			Hostname:               setArgs.hostname,
 			OperatorUser:           setArgs.opUser,
+			NoSNAT:                 !setArgs.snat,
 			ForceDaemon:            setArgs.forceDaemon,
 			AutoUpdate: ipn.AutoUpdatePrefs{
 				Check: setArgs.updateCheck,
@@ -140,10 +151,22 @@ func runSet(ctx context.Context, args []string) (retErr error) {
 			AppConnector: ipn.AppConnectorPrefs{
 				Advertise: setArgs.advertiseConnector,
 			},
-			PostureChecking: setArgs.postureChecking,
+			PostureChecking:     setArgs.postureChecking,
+			NoStatefulFiltering: opt.NewBool(!setArgs.statefulFiltering),
 		},
 	}
 
+	if effectiveGOOS() == "linux" {
+		nfMode, warning, err := netfilterModeFromFlag(setArgs.netfilterMode)
+		if err != nil {
+			return err
+		}
+		if warning != "" {
+			warnf(warning)
+		}
+		maskedPrefs.Prefs.NetfilterMode = nfMode
+	}
+
 	if setArgs.exitNodeIP != "" {
 		if err := maskedPrefs.Prefs.SetExitNodeIP(setArgs.exitNodeIP, st); err != nil {
 			var e ipn.ExitNodeLocalIPError

cmd/tailscale/cli/up.go

@@ -295,25 +295,42 @@ func prefsFromUpArgs(upArgs upArgsT, warnf logger.Logf, st *ipnstate.Status, goo
 
 		// Backfills for NoStatefulFiltering occur when loading a profile; just set it explicitly here.
 		prefs.NoStatefulFiltering.Set(!upArgs.statefulFiltering)
-
+		v, warning, err := netfilterModeFromFlag(upArgs.netfilterMode)
-		switch upArgs.netfilterMode {
+		if err != nil {
-		case "on":
+			return nil, err
-			prefs.NetfilterMode = preftype.NetfilterOn
+		}
-		case "nodivert":
+		prefs.NetfilterMode = v
-			prefs.NetfilterMode = preftype.NetfilterNoDivert
+		if warning != "" {
-			warnf("netfilter=nodivert; add iptables calls to ts-* chains manually.")
+			warnf(warning)
-		case "off":
-			prefs.NetfilterMode = preftype.NetfilterOff
-			if defaultNetfilterMode() != "off" {
-				warnf("netfilter=off; configure iptables yourself.")
-			}
-		default:
-			return nil, fmt.Errorf("invalid value --netfilter-mode=%q", upArgs.netfilterMode)
 		}
 	}
 	return prefs, nil
 }
 
+// netfilterModeFromFlag returns the preftype.NetfilterMode for the provided
+// flag value. It returns a warning if there is something the user should know
+// about the value.
+func netfilterModeFromFlag(v string) (_ preftype.NetfilterMode, warning string, _ error) {
+	switch v {
+	case "on", "nodivert", "off":
+	default:
+		return preftype.NetfilterOn, "", fmt.Errorf("invalid value --netfilter-mode=%q", v)
+	}
+	m, err := preftype.ParseNetfilterMode(v)
+	if err != nil {
+		return preftype.NetfilterOn, "", err
+	}
+	switch m {
+	case preftype.NetfilterNoDivert:
+		warning = "netfilter=nodivert; add iptables calls to ts-* chains manually."
+	case preftype.NetfilterOff:
+		if defaultNetfilterMode() != "off" {
+			warning = "netfilter=off; configure iptables yourself."
+		}
+	}
+	return m, warning, nil
+}
+
 // updatePrefs returns how to edit preferences based on the
 // flag-provided 'prefs' and the currently active 'curPrefs'.
 //