Add back random iproute2 table index

This reverts commit e71911f94d.

internal/wintun/wintun_windows.go

@@ -39,6 +39,10 @@ func closeAdapter(wintun *Adapter) {
 // deterministically. If it is set to nil, the GUID is chosen by the system at random,
 // and hence a new NLA entry is created for each new adapter.
 func CreateAdapter(name string, tunnelType string, requestedGUID *windows.GUID) (wintun *Adapter, err error) {
+	err = procWintunCloseAdapter.Find()
+	if err != nil {
+		return
+	}
 	var name16 *uint16
 	name16, err = windows.UTF16PtrFromString(name)
 	if err != nil {

redirect_linux.go

@@ -69,6 +69,7 @@ func (r *autoRedirect) Start() error {
 			r.androidSu = true
 			for _, suPath := range []string{
 				"su",
+				"/product/bin/su",
 				"/system/bin/su",
 			} {
 				r.suPath, err = exec.LookPath(suPath)

redirect_nftables.go

@@ -182,6 +182,25 @@ func (r *autoRedirect) setupNFTables() error {
 				},
 			},
 		})
+		nft.AddRule(&nftables.Rule{
+			Table: table,
+			Chain: chainPreRoutingUDP,
+			Exprs: []expr.Any{
+				&expr.Meta{
+					Key:      expr.MetaKeyIIFNAME,
+					Register: 1,
+				},
+				&expr.Cmp{
+					Op:       expr.CmpOpEq,
+					Register: 1,
+					Data:     nftablesIfname(r.tunOptions.Name),
+				},
+				&expr.Counter{},
+				&expr.Verdict{
+					Kind: expr.VerdictReturn,
+				},
+			},
+		})
 		nft.AddRule(&nftables.Rule{
 			Table: table,
 			Chain: chainPreRoutingUDP,

redirect_nftables_rules.go

@@ -103,10 +103,6 @@ func (r *autoRedirect) nftablesCreateLocalAddressSets(
 				update = true
 			}
 		}
-		localAddresses6 = common.Filter(localAddresses6, func(it netip.Prefix) bool {
-			address := it.Addr()
-			return address.IsLoopback() || address.IsGlobalUnicast() && !address.IsPrivate()
-		})
 		if len(lastAddresses) == 0 || update {
 			_, err := nftablesCreateIPSet(nft, table, 6, "inet6_local_address_set", nftables.TableFamilyIPv6, nil, localAddresses6, false, update)
 			if err != nil {

stack_system_nat.go

@@ -11,6 +11,7 @@ import (
 )
 
 type TCPNat struct {
+	timeout    time.Duration
 	portIndex  uint16
 	portAccess sync.RWMutex
 	addrAccess sync.RWMutex
@@ -19,6 +20,7 @@ type TCPNat struct {
 }
 
 type TCPSession struct {
+	sync.Mutex
 	Source      netip.AddrPort
 	Destination netip.AddrPort
 	LastActive  time.Time
@@ -26,38 +28,41 @@ type TCPSession struct {
 
 func NewNat(ctx context.Context, timeout time.Duration) *TCPNat {
 	natMap := &TCPNat{
+		timeout:   timeout,
 		portIndex: 10000,
 		addrMap:   make(map[netip.AddrPort]uint16),
 		portMap:   make(map[uint16]*TCPSession),
 	}
-	go natMap.loopCheckTimeout(ctx, timeout)
+	go natMap.loopCheckTimeout(ctx)
 	return natMap
 }
 
-func (n *TCPNat) loopCheckTimeout(ctx context.Context, timeout time.Duration) {
-	ticker := time.NewTicker(timeout)
+func (n *TCPNat) loopCheckTimeout(ctx context.Context) {
+	ticker := time.NewTicker(n.timeout)
 	defer ticker.Stop()
 	for {
 		select {
 		case <-ticker.C:
-			n.checkTimeout(timeout)
+			n.checkTimeout()
 		case <-ctx.Done():
 			return
 		}
 	}
 }
 
-func (n *TCPNat) checkTimeout(timeout time.Duration) {
+func (n *TCPNat) checkTimeout() {
 	now := time.Now()
 	n.portAccess.Lock()
 	defer n.portAccess.Unlock()
 	n.addrAccess.Lock()
 	defer n.addrAccess.Unlock()
 	for natPort, session := range n.portMap {
-		if now.Sub(session.LastActive) > timeout {
+		session.Lock()
+		if now.Sub(session.LastActive) > n.timeout {
 			delete(n.addrMap, session.Source)
 			delete(n.portMap, natPort)
 		}
+		session.Unlock()
 	}
 }
 
@@ -66,7 +71,11 @@ func (n *TCPNat) LookupBack(port uint16) *TCPSession {
 	session := n.portMap[port]
 	n.portAccess.RUnlock()
 	if session != nil {
-		session.LastActive = time.Now()
+		session.Lock()
+		if time.Since(session.LastActive) > time.Second {
+			session.LastActive = time.Now()
+		}
+		session.Unlock()
 	}
 	return session
 }

tun.go

@@ -52,44 +52,46 @@ type DarwinTUN interface {
 }
 
 const (
-	DefaultIPRoute2TableIndex = 2022
-	DefaultIPRoute2RuleIndex  = 9000
+	DefaultIPRoute2TableIndex                    = 2022
+	DefaultIPRoute2RuleIndex                     = 9000
+	DefaultIPRoute2AutoRedirectFallbackRuleIndex = 32768
 )
 
 type Options struct {
-	Name                     string
-	Inet4Address             []netip.Prefix
-	Inet6Address             []netip.Prefix
-	MTU                      uint32
-	GSO                      bool
-	AutoRoute                bool
-	InterfaceScope           bool
-	Inet4Gateway             netip.Addr
-	Inet6Gateway             netip.Addr
-	DNSServers               []netip.Addr
-	IPRoute2TableIndex       int
-	IPRoute2RuleIndex        int
-	AutoRedirectMarkMode     bool
-	AutoRedirectInputMark    uint32
-	AutoRedirectOutputMark   uint32
-	Inet4LoopbackAddress     []netip.Addr
-	Inet6LoopbackAddress     []netip.Addr
-	StrictRoute              bool
-	Inet4RouteAddress        []netip.Prefix
-	Inet6RouteAddress        []netip.Prefix
-	Inet4RouteExcludeAddress []netip.Prefix
-	Inet6RouteExcludeAddress []netip.Prefix
-	IncludeInterface         []string
-	ExcludeInterface         []string
-	IncludeUID               []ranges.Range[uint32]
-	ExcludeUID               []ranges.Range[uint32]
-	IncludeAndroidUser       []int
-	IncludePackage           []string
-	ExcludePackage           []string
-	InterfaceFinder          control.InterfaceFinder
-	InterfaceMonitor         DefaultInterfaceMonitor
-	FileDescriptor           int
-	Logger                   logger.Logger
+	Name                                  string
+	Inet4Address                          []netip.Prefix
+	Inet6Address                          []netip.Prefix
+	MTU                                   uint32
+	GSO                                   bool
+	AutoRoute                             bool
+	InterfaceScope                        bool
+	Inet4Gateway                          netip.Addr
+	Inet6Gateway                          netip.Addr
+	DNSServers                            []netip.Addr
+	IPRoute2TableIndex                    int
+	IPRoute2RuleIndex                     int
+	IPRoute2AutoRedirectFallbackRuleIndex int
+	AutoRedirectMarkMode                  bool
+	AutoRedirectInputMark                 uint32
+	AutoRedirectOutputMark                uint32
+	Inet4LoopbackAddress                  []netip.Addr
+	Inet6LoopbackAddress                  []netip.Addr
+	StrictRoute                           bool
+	Inet4RouteAddress                     []netip.Prefix
+	Inet6RouteAddress                     []netip.Prefix
+	Inet4RouteExcludeAddress              []netip.Prefix
+	Inet6RouteExcludeAddress              []netip.Prefix
+	IncludeInterface                      []string
+	ExcludeInterface                      []string
+	IncludeUID                            []ranges.Range[uint32]
+	ExcludeUID                            []ranges.Range[uint32]
+	IncludeAndroidUser                    []int
+	IncludePackage                        []string
+	ExcludePackage                        []string
+	InterfaceFinder                       control.InterfaceFinder
+	InterfaceMonitor                      DefaultInterfaceMonitor
+	FileDescriptor                        int
+	Logger                                logger.Logger
 
 	// No work for TCP, do not use.
 	_TXChecksumOffload bool

tun_darwin.go

@@ -152,7 +152,10 @@ func (t *NativeTun) Start() error {
 
 func (t *NativeTun) Close() error {
 	defer flushDNSCache()
-	return E.Errors(t.unsetRoutes(), t.tunFile.Close())
+	t.stopFd.Stop()
+	err := E.Errors(t.unsetRoutes(), t.tunFile.Close())
+	t.stopFd.Close()
+	return err
 }
 
 func (t *NativeTun) Read(p []byte) (n int, err error) {
@@ -347,6 +350,9 @@ func (t *NativeTun) BatchRead() ([]*buf.Buffer, error) {
 		t.buffers = t.buffers[:0]
 		return nil, errno
 	}
+	if n < 0 {
+		return nil, os.ErrClosed
+	}
 	if n < 1 {
 		return nil, nil
 	}

tun_linux.go

@@ -130,7 +130,7 @@ func (t *NativeTun) configure(tunLink netlink.Link) error {
 		for _, address := range t.options.Inet4Address {
 			addr4, _ := netlink.ParseAddr(address.String())
 			err = netlink.AddrAdd(tunLink, addr4)
-			if err != nil {
+			if err != nil && !errors.Is(err, unix.EEXIST) {
 				return err
 			}
 		}
@@ -139,7 +139,7 @@ func (t *NativeTun) configure(tunLink netlink.Link) error {
 		for _, address := range t.options.Inet6Address {
 			addr6, _ := netlink.ParseAddr(address.String())
 			err = netlink.AddrAdd(tunLink, addr6)
-			if err != nil {
+			if err != nil && !errors.Is(err, unix.EEXIST) {
 				return err
 			}
 		}
@@ -315,6 +315,7 @@ func (t *NativeTun) Close() error {
 	if t.interfaceCallback != nil {
 		t.options.InterfaceMonitor.UnregisterCallback(t.interfaceCallback)
 	}
+	t.unsetAddresses()
 	return E.Errors(t.unsetRoute(), t.unsetRules(), common.Close(common.PtrOrNil(t.tunFile)))
 }
 
@@ -616,6 +617,22 @@ func (t *NativeTun) rules() []*netlink.Rule {
 			it.Family = unix.AF_INET6
 			rules = append(rules, it)
 		}
+		// Fallback rules after system default rules (32766: main, 32767: default)
+		// Only reached when main and default tables have no route
+		if p4 {
+			it = netlink.NewRule()
+			it.Priority = t.options.IPRoute2AutoRedirectFallbackRuleIndex
+			it.Table = t.options.IPRoute2TableIndex
+			it.Family = unix.AF_INET
+			rules = append(rules, it)
+		}
+		if p6 {
+			it = netlink.NewRule()
+			it.Priority = t.options.IPRoute2AutoRedirectFallbackRuleIndex
+			it.Table = t.options.IPRoute2TableIndex
+			it.Family = unix.AF_INET6
+			rules = append(rules, it)
+		}
 		return rules
 	}
 
@@ -989,7 +1006,7 @@ func (t *NativeTun) unsetRules() error {
 		for _, rule := range ruleList {
 			ruleStart := t.options.IPRoute2RuleIndex
 			ruleEnd := ruleStart + 10
-			if rule.Priority >= ruleStart && rule.Priority <= ruleEnd {
+			if rule.Priority >= ruleStart && rule.Priority <= ruleEnd || (t.options.AutoRedirectMarkMode && rule.Priority == t.options.IPRoute2AutoRedirectFallbackRuleIndex) {
 				ruleToDel := netlink.NewRule()
 				ruleToDel.Family = rule.Family
 				ruleToDel.Priority = rule.Priority
@@ -1003,6 +1020,24 @@ func (t *NativeTun) unsetRules() error {
 	return nil
 }
 
+func (t *NativeTun) unsetAddresses() {
+	if t.options.FileDescriptor > 0 {
+		return
+	}
+	tunLink, err := netlink.LinkByName(t.options.Name)
+	if err != nil {
+		return
+	}
+	for _, address := range t.options.Inet4Address {
+		addr, _ := netlink.ParseAddr(address.String())
+		_ = netlink.AddrDel(tunLink, addr)
+	}
+	for _, address := range t.options.Inet6Address {
+		addr, _ := netlink.ParseAddr(address.String())
+		_ = netlink.AddrDel(tunLink, addr)
+	}
+}
+
 func (t *NativeTun) resetRules() error {
 	t.unsetRules()
 	return t.setRules()

tun_windows.go

@@ -181,6 +181,13 @@ func (t *NativeTun) Start() error {
 		return err
 	}
 	if t.options.StrictRoute {
+		major, _, _ := windows.RtlGetNtVersionNumbers()
+		if major < 10 {
+			if t.options.Logger != nil {
+				t.options.Logger.Warn("strict routing is not supported on Windows versions below 10")
+			}
+			return nil
+		}
 		var engine uintptr
 		session := &winsys.FWPM_SESSION0{Flags: winsys.FWPM_SESSION_FLAG_DYNAMIC}
 		err := winsys.FwpmEngineOpen0(nil, winsys.RPC_C_AUTHN_DEFAULT, nil, session, unsafe.Pointer(&engine))
@@ -395,15 +402,16 @@ retry:
 
 func (t *NativeTun) ReadPacket() ([]byte, func(), error) {
 	t.running.Add(1)
-	defer t.running.Done()
 retry:
 	if t.close.Load() == 1 {
+		t.running.Done()
 		return nil, nil, os.ErrClosed
 	}
 	start := nanotime()
 	shouldSpin := t.rate.current.Load() >= spinloopRateThreshold && uint64(start-t.rate.nextStartTime.Load()) <= rateMeasurementGranularity*2
 	for {
 		if t.close.Load() == 1 {
+			t.running.Done()
 			return nil, nil, os.ErrClosed
 		}
 		packet, err := t.session.ReceivePacket()
@@ -411,7 +419,10 @@ retry:
 		case nil:
 			packetSize := len(packet)
 			t.rate.update(uint64(packetSize))
-			return packet, func() { t.session.ReleaseReceivePacket(packet) }, nil
+			return packet, func() {
+				t.session.ReleaseReceivePacket(packet)
+				t.running.Done()
+			}, nil
 		case windows.ERROR_NO_MORE_ITEMS:
 			if !shouldSpin || uint64(nanotime()-start) >= spinloopDuration {
 				windows.WaitForSingleObject(t.readWait, windows.INFINITE)
@@ -420,10 +431,13 @@ retry:
 			procyield(1)
 			continue
 		case windows.ERROR_HANDLE_EOF:
+			t.running.Done()
 			return nil, nil, os.ErrClosed
 		case windows.ERROR_INVALID_DATA:
+			t.running.Done()
 			return nil, nil, errors.New("send ring corrupt")
 		}
+		t.running.Done()
 		return nil, nil, fmt.Errorf("read failed: %w", err)
 	}
 }