all: depend on zstd unconditionally, remove plumbing to make it optional

All platforms use it at this point, including iOS which was the
original hold out for memory reasons. No more reason to make it
optional.

Updates #9332

Change-Id: I743fbc2f370921a852fbcebf4eb9821e2bdd3086
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

cmd/tailscaled/depaware.txt

@@ -290,7 +290,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/paths                                          from tailscale.com/ipn/ipnlocal+
      💣 tailscale.com/portlist                                       from tailscale.com/ipn/ipnlocal
         tailscale.com/safesocket                                     from tailscale.com/client/tailscale+
-        tailscale.com/smallzstd                                      from tailscale.com/cmd/tailscaled+
+        tailscale.com/smallzstd                                      from tailscale.com/control/controlclient+
   LD 💣 tailscale.com/ssh/tailssh                                    from tailscale.com/cmd/tailscaled
         tailscale.com/syncs                                          from tailscale.com/net/netcheck+
         tailscale.com/tailcfg                                        from tailscale.com/client/tailscale/apitype+

cmd/tailscaled/tailscaled.go

@@ -48,7 +48,6 @@ import (
 	"tailscale.com/net/tstun"
 	"tailscale.com/paths"
 	"tailscale.com/safesocket"
-	"tailscale.com/smallzstd"
 	"tailscale.com/syncs"
 	"tailscale.com/tsd"
 	"tailscale.com/tsweb/varz"
@@ -551,9 +550,6 @@ func getLocalBackend(ctx context.Context, logf logger.Logf, logID logid.PublicID
 	if root := lb.TailscaleVarRoot(); root != "" {
 		dnsfallback.SetCachePath(filepath.Join(root, "derpmap.cached.json"), logf)
 	}
-	lb.SetDecompressor(func() (controlclient.Decompressor, error) {
-		return smallzstd.NewDecoder(nil)
-	})
 	configureTaildrop(logf, lb)
 	if err := ns.Start(lb); err != nil {
 		log.Fatalf("failed to start netstack: %v", err)

cmd/tsconnect/wasm/wasm_js.go

@@ -35,7 +35,6 @@ import (
 	"tailscale.com/net/netns"
 	"tailscale.com/net/tsdial"
 	"tailscale.com/safesocket"
-	"tailscale.com/smallzstd"
 	"tailscale.com/tailcfg"
 	"tailscale.com/tsd"
 	"tailscale.com/wgengine"
@@ -133,9 +132,6 @@ func newIPN(jsConfig js.Value) map[string]any {
 	if err := ns.Start(lb); err != nil {
 		log.Fatalf("failed to start netstack: %v", err)
 	}
-	lb.SetDecompressor(func() (controlclient.Decompressor, error) {
-		return smallzstd.NewDecoder(nil)
-	})
 	srv.SetLocalBackend(lb)
 
 	jsIPN := &jsIPN{

control/controlclient/direct.go

@@ -43,6 +43,7 @@ import (
 	"tailscale.com/net/tlsdial"
 	"tailscale.com/net/tsdial"
 	"tailscale.com/net/tshttpproxy"
+	"tailscale.com/smallzstd"
 	"tailscale.com/syncs"
 	"tailscale.com/tailcfg"
 	"tailscale.com/tka"
@@ -68,7 +69,6 @@ type Direct struct {
 	serverURL             string // URL of the tailcontrol server
 	clock                 tstime.Clock
 	lastPrintMap          time.Time
-	newDecompressor       func() (Decompressor, error)
 	logf                  logger.Logf
 	netMon                *netmon.Monitor // or nil
 	discoPubKey           key.DiscoPublic
@@ -119,7 +119,6 @@ type Options struct {
 	Clock                tstime.Clock
 	Hostinfo             *tailcfg.Hostinfo // non-nil passes ownership, nil means to use default using os.Hostname, etc
 	DiscoPublicKey       key.DiscoPublic
-	NewDecompressor      func() (Decompressor, error)
 	Logf                 logger.Logf
 	HTTPTestClient       *http.Client                 // optional HTTP client to use (for tests only)
 	NoiseTestClient      *http.Client                 // optional HTTP client to use for noise RPCs (tests only)
@@ -254,7 +253,6 @@ func NewDirect(opts Options) (*Direct, error) {
 		serverURL:             opts.ServerURL,
 		clock:                 opts.Clock,
 		logf:                  opts.Logf,
-		newDecompressor:       opts.NewDecompressor,
 		persist:               opts.Persist.View(),
 		authKey:               opts.AuthKey,
 		discoPubKey:           opts.DiscoPublicKey,
@@ -891,9 +889,7 @@ func (c *Direct) sendMapRequest(ctx context.Context, isStreaming bool, nu Netmap
 		old := request.DebugFlags
 		request.DebugFlags = append(old[:len(old):len(old)], extraDebugFlags...)
 	}
-	if c.newDecompressor != nil {
-		request.Compress = "zstd"
-	}
+	request.Compress = "zstd"
 
 	bodyData, err := encode(request, serverKey, serverNoiseKey, machinePrivKey)
 	if err != nil {
@@ -1177,19 +1173,14 @@ func (c *Direct) decodeMsg(msg []byte, v any, mkey key.MachinePrivate) error {
 	} else {
 		decrypted = msg
 	}
-	var b []byte
-	if c.newDecompressor == nil {
-		b = decrypted
-	} else {
-		decoder, err := c.newDecompressor()
-		if err != nil {
-			return err
-		}
-		defer decoder.Close()
-		b, err = decoder.DecodeAll(decrypted, nil)
-		if err != nil {
-			return err
-		}
+	decoder, err := smallzstd.NewDecoder(nil)
+	if err != nil {
+		return err
+	}
+	defer decoder.Close()
+	b, err := decoder.DecodeAll(decrypted, nil)
+	if err != nil {
+		return err
 	}
 	if debugMap() {
 		var buf bytes.Buffer

ipn/ipnlocal/local.go

@@ -153,10 +153,9 @@ type LocalBackend struct {
 	portpoll              *portlist.Poller // may be nil
 	portpollOnce          sync.Once        // guards starting readPoller
 	gotPortPollRes        chan struct{}    // closed upon first readPoller result
-	newDecompressor       func() (controlclient.Decompressor, error)
-	varRoot               string         // or empty if SetVarRoot never called
-	logFlushFunc          func()         // or nil if SetLogFlusher wasn't called
-	em                    *expiryManager // non-nil
+	varRoot               string           // or empty if SetVarRoot never called
+	logFlushFunc          func()           // or nil if SetLogFlusher wasn't called
+	em                    *expiryManager   // non-nil
 	sshAtomicBool         atomic.Bool
 	shutdownCalled        bool // if Shutdown has been called
 	debugSink             *capture.Sink
@@ -898,16 +897,6 @@ func (b *LocalBackend) peerCapsLocked(src netip.Addr) tailcfg.PeerCapMap {
 	return nil
 }
 
-// SetDecompressor sets a decompression function, which must be a zstd
-// reader.
-//
-// This exists because the iOS/Mac NetworkExtension is very resource
-// constrained, and the zstd package is too heavy to fit in the
-// constrained RSS limit.
-func (b *LocalBackend) SetDecompressor(fn func() (controlclient.Decompressor, error)) {
-	b.newDecompressor = fn
-}
-
 // SetControlClientStatus is the callback invoked by the control client whenever it posts a new status.
 // Among other things, this is where we update the netmap, packet filters, DNS and DERP maps.
 func (b *LocalBackend) SetControlClientStatus(c controlclient.Client, st controlclient.Status) {
@@ -1460,7 +1449,6 @@ func (b *LocalBackend) Start(opts ipn.Options) error {
 		ServerURL:            serverURL,
 		AuthKey:              opts.AuthKey,
 		Hostinfo:             hostinfo,
-		NewDecompressor:      b.newDecompressor,
 		HTTPTestClient:       httpTestClient,
 		DiscoPublicKey:       discoPublic,
 		DebugFlags:           debugFlags,

tsnet/tsnet.go

@@ -550,9 +550,6 @@ func (s *Server) start() (reterr error) {
 		return fmt.Errorf("failed to start netstack: %w", err)
 	}
 	closePool.addFunc(func() { s.lb.Shutdown() })
-	lb.SetDecompressor(func() (controlclient.Decompressor, error) {
-		return smallzstd.NewDecoder(nil)
-	})
 	prefs := ipn.NewPrefs()
 	prefs.Hostname = s.hostname
 	prefs.WantRunning = true

tstest/integration/tailscaled_deps_test_darwin.go

@@ -33,7 +33,6 @@ import (
 	_ "tailscale.com/net/tstun"
 	_ "tailscale.com/paths"
 	_ "tailscale.com/safesocket"
-	_ "tailscale.com/smallzstd"
 	_ "tailscale.com/ssh/tailssh"
 	_ "tailscale.com/syncs"
 	_ "tailscale.com/tailcfg"

tstest/integration/tailscaled_deps_test_freebsd.go

@@ -33,7 +33,6 @@ import (
 	_ "tailscale.com/net/tstun"
 	_ "tailscale.com/paths"
 	_ "tailscale.com/safesocket"
-	_ "tailscale.com/smallzstd"
 	_ "tailscale.com/ssh/tailssh"
 	_ "tailscale.com/syncs"
 	_ "tailscale.com/tailcfg"

tstest/integration/tailscaled_deps_test_linux.go

@@ -33,7 +33,6 @@ import (
 	_ "tailscale.com/net/tstun"
 	_ "tailscale.com/paths"
 	_ "tailscale.com/safesocket"
-	_ "tailscale.com/smallzstd"
 	_ "tailscale.com/ssh/tailssh"
 	_ "tailscale.com/syncs"
 	_ "tailscale.com/tailcfg"

tstest/integration/tailscaled_deps_test_openbsd.go

@@ -33,7 +33,6 @@ import (
 	_ "tailscale.com/net/tstun"
 	_ "tailscale.com/paths"
 	_ "tailscale.com/safesocket"
-	_ "tailscale.com/smallzstd"
 	_ "tailscale.com/ssh/tailssh"
 	_ "tailscale.com/syncs"
 	_ "tailscale.com/tailcfg"

tstest/integration/tailscaled_deps_test_windows.go

@@ -41,7 +41,6 @@ import (
 	_ "tailscale.com/net/tstun"
 	_ "tailscale.com/paths"
 	_ "tailscale.com/safesocket"
-	_ "tailscale.com/smallzstd"
 	_ "tailscale.com/syncs"
 	_ "tailscale.com/tailcfg"
 	_ "tailscale.com/tsd"