TUN inbound: Refine gateway and autoSystemRoutingTable on Linux (#6398)

https://github.com/XTLS/Xray-core/pull/6398#issuecomment-4880261591

go.mod

@@ -8,12 +8,13 @@ require (
 	github.com/ghodss/yaml v1.0.1-0.20220118164431-d8423dcdf344
 	github.com/golang/mock v1.7.0-rc.1
 	github.com/google/go-cmp v0.7.0
+	github.com/google/uuid v1.6.0
 	github.com/gorilla/websocket v1.5.3
-	github.com/klauspost/cpuid/v2 v2.3.0
+	github.com/klauspost/cpuid/v2 v2.4.0
 	github.com/miekg/dns v1.1.72
 	github.com/pelletier/go-toml v1.9.5
 	github.com/pion/stun/v3 v3.1.6
-	github.com/pires/go-proxyproto v0.12.0
+	github.com/pires/go-proxyproto v0.14.0
 	github.com/refraction-networking/utls v1.8.3-0.20260301010127-aa6edf4b11af
 	github.com/robfig/cron/v3 v3.0.1
 	github.com/sagernet/sing v0.5.1
@@ -30,7 +31,7 @@ require (
 	golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2
 	golang.zx2c4.com/wireguard v0.0.0-20250521234502-f333402bd9cb
 	golang.zx2c4.com/wireguard/windows v1.0.1
-	google.golang.org/grpc v1.81.1
+	google.golang.org/grpc v1.82.0
 	google.golang.org/protobuf v1.36.11
 	gvisor.dev/gvisor v0.0.0-20260122175437-89a5d21be8f0
 	h12.io/socks v1.0.3
@@ -55,7 +56,7 @@ require (
 	golang.org/x/text v0.38.0 // indirect
 	golang.org/x/time v0.14.0 // indirect
 	golang.org/x/tools v0.45.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20260226221140-a57be14db171 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20260414002931-afd174a4e478 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -33,8 +33,8 @@ github.com/juju/ratelimit v1.0.2 h1:sRxmtRiajbvrcLQT7S+JbqU0ntsb9W2yhSdNN8tWfaI=
 github.com/juju/ratelimit v1.0.2/go.mod h1:qapgC/Gy+xNh9UxzV13HGGl/6UXNN+ct+vwSgWNm/qk=
 github.com/klauspost/compress v1.17.4 h1:Ej5ixsIri7BrIjBkRZLTo6ghwrEtHFk7ijlczPW4fZ4=
 github.com/klauspost/compress v1.17.4/go.mod h1:/dCuZOvVtNoHsyb+cuJD3itjs3NbnF6KH9zAO4BDxPM=
-github.com/klauspost/cpuid/v2 v2.3.0 h1:S4CRMLnYUhGeDFDqkGriYKdfoFlDnMtqTiI/sFzhA9Y=
-github.com/klauspost/cpuid/v2 v2.3.0/go.mod h1:hqwkgyIinND0mEev00jJYCxPNVRVXFQeu1XKlok6oO0=
+github.com/klauspost/cpuid/v2 v2.4.0 h1:S6Hrbc7+ywsr0r+RLapfGBHfyefhCTwEh3A0tV913Dw=
+github.com/klauspost/cpuid/v2 v2.4.0/go.mod h1:19jmZ9mjzoF//ddRSUsv0zfBTJWh3QJh9FNxZTMrGxU=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
 github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
@@ -53,8 +53,8 @@ github.com/pion/stun/v3 v3.1.6 h1:WnhsD0eHCiwCfKNkVx0VJJwr2Y3eV4Ueih3KJ+dfZy8=
 github.com/pion/stun/v3 v3.1.6/go.mod h1:zRUghXSQU32Lx5orJsz3uYMkIihweXb3mu5gIns02fs=
 github.com/pion/transport/v4 v4.0.2 h1:ifYlPqNwsy6aKQ9y8yzxXlHae5431ZrH2avkD/Rn6Tk=
 github.com/pion/transport/v4 v4.0.2/go.mod h1:06hFI+jCFcok2X2MekVufNZ/uzNZXivGBPfviSVcjgM=
-github.com/pires/go-proxyproto v0.12.0 h1:TTCxD66dU898tahivkqc3hoceZp7P44FnorWyo9d5vM=
-github.com/pires/go-proxyproto v0.12.0/go.mod h1:qUvfqUMEoX7T8g0q7TQLDnhMjdTrxnG0hvpMn+7ePNI=
+github.com/pires/go-proxyproto v0.14.0 h1:2vIGIfVG8eVRsKF0xukEoeT5RWhDXxBU0uv6smLOKdI=
+github.com/pires/go-proxyproto v0.14.0/go.mod h1:OXsCrKwrK2tXS9YrI5tkHx5xaQlO8FH3lFW76orFh24=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/quic-go/qpack v0.6.0 h1:g7W+BMYynC1LbYLSqRt8PBg5Tgwxn214ZZR34VIOjz8=
@@ -147,10 +147,10 @@ golang.zx2c4.com/wireguard/windows v1.0.1 h1:eOxiDVbywPC+ZQqvdCK7x+ZwWXKbYv50TtH
 golang.zx2c4.com/wireguard/windows v1.0.1/go.mod h1:+fbT3FFdX4zzYDLwJh5+HPEcNN/3HyNdzhNSVsQM+zs=
 gonum.org/v1/gonum v0.17.0 h1:VbpOemQlsSMrYmn7T2OUvQ4dqxQXU+ouZFQsZOx50z4=
 gonum.org/v1/gonum v0.17.0/go.mod h1:El3tOrEuMpv2UdMrbNlKEh9vd86bmQ6vqIcDwxEOc1E=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20260226221140-a57be14db171 h1:ggcbiqK8WWh6l1dnltU4BgWGIGo+EVYxCaAPih/zQXQ=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20260226221140-a57be14db171/go.mod h1:4Hqkh8ycfw05ld/3BWL7rJOSfebL2Q+DVDeRgYgxUU8=
-google.golang.org/grpc v1.81.1 h1:VnnIIZ88UzOOKLukQi+ImGz8O1Wdp8nAGGnvOfEIWQQ=
-google.golang.org/grpc v1.81.1/go.mod h1:xGH9GfzOyMTGIOXBJmXt+BX/V0kcdQbdcuwQ/zNw42I=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20260414002931-afd174a4e478 h1:RmoJA1ujG+/lRGNfUnOMfhCy5EipVMyvUE+KNbPbTlw=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20260414002931-afd174a4e478/go.mod h1:4Hqkh8ycfw05ld/3BWL7rJOSfebL2Q+DVDeRgYgxUU8=
+google.golang.org/grpc v1.82.0 h1:vguDnZUPjE26w09A63VoxZPnvPjB5Riyc0mkXPFmAIU=
+google.golang.org/grpc v1.82.0/go.mod h1:yzTZ1TB1Z3SG+LIYaI+WiE8D5+PZ3ArnrSp8zF3+/ZA=
 google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
 google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

proxy/dns/dns.go

@@ -215,7 +215,7 @@ func (h *Handler) Process(ctx context.Context, link *transport.Link, d internet.
 	}
 
 	if session.TimeoutOnlyFromContext(ctx) {
-		ctx = context.WithoutCancel(ctx)
+		ctx = context.Background()
 	}
 
 	ctx, cancel := context.WithCancel(ctx)

proxy/hysteria/account/config.go

@@ -5,14 +5,14 @@ import (
 
 	"github.com/xtls/xray-core/common/net"
 	"github.com/xtls/xray-core/common/protocol"
-	"github.com/xtls/xray-core/common/uuid"
 
+	"github.com/google/uuid"
 	"google.golang.org/protobuf/proto"
 )
 
 func (a *Account) AsAccount() (protocol.Account, error) {
 	var VR net.Port
-	if id, err := uuid.ParseString(a.Auth); err == nil {
+	if id, err := uuid.Parse(a.Auth); err == nil {
 		VR = net.PortFromBytes(id[6:8])
 	}
 	return &MemoryAccount{
@@ -41,29 +41,71 @@ func (a *MemoryAccount) ToProto() proto.Message {
 
 type Validator struct {
 	users sync.Map
+	ids   sync.Map
+	mu    sync.Mutex
 }
 
 func NewValidator() *Validator {
 	return &Validator{}
 }
 
-func (v *Validator) Add(user *protocol.MemoryUser) error {
+func (v *Validator) Add(user *protocol.MemoryUser) (err error) {
+	v.mu.Lock()
 	v.users.Store(user.Account.(*MemoryAccount).Auth, user)
-	return nil
+	if id, err := uuid.Parse(user.Account.(*MemoryAccount).Auth); err == nil {
+		id[6] = 0
+		id[7] = 0
+		v.ids.Store(id, user)
+	}
+	v.mu.Unlock()
+	return
 }
 
-func (v *Validator) DelByEmail(email string) error {
+func (v *Validator) DelByEmail(email string) (err error) {
+	v.mu.Lock()
 	if user := v.GetByEmail(email); user != nil {
-		v.users.Delete(user.Account.(*MemoryAccount).Auth)
+		auth := user.Account.(*MemoryAccount).Auth
+		v.users.Delete(auth)
+		if id, err := uuid.Parse(auth); err == nil {
+			id[6] = 0
+			id[7] = 0
+			v.ids.Delete(id)
+		}
 	}
-	return nil
+	v.mu.Unlock()
+	return
 }
 
-func (v *Validator) Get(auth string) *protocol.MemoryUser {
-	if value, ok := v.users.Load(auth); ok {
-		return value.(*protocol.MemoryUser)
+func (v *Validator) Get(auth string) (user *protocol.MemoryUser) {
+	if id, err := uuid.Parse(auth); err == nil {
+		if user = v.GetByID(id); user != nil {
+			VR := net.PortFromBytes(id[6:8])
+			if user.Account.(*MemoryAccount).VR != VR {
+				user = &protocol.MemoryUser{
+					Email: user.Email,
+					Level: user.Level,
+					Account: &MemoryAccount{
+						Auth: auth,
+						VR:   VR,
+					},
+				}
+			}
+		}
+		return
 	}
-	return nil
+	if value, ok := v.users.Load(auth); ok {
+		user = value.(*protocol.MemoryUser)
+	}
+	return
+}
+
+func (v *Validator) GetByID(id uuid.UUID) (user *protocol.MemoryUser) {
+	id[6] = 0
+	id[7] = 0
+	if value, ok := v.ids.Load(id); ok {
+		user = value.(*protocol.MemoryUser)
+	}
+	return
 }
 
 func (v *Validator) GetByEmail(email string) (user *protocol.MemoryUser) {

proxy/tun/README.md

@@ -14,11 +14,11 @@ Plainly enabling it in the config probably will result nothing, or lock your rou
 
 ## DETAILS
 
-Current implementation does not contain options to configure network level addresses, routing or rules.
-Enabling the feature will result only tun interface up, and that's it. \
-This is explicit decision, significantly simplifying implementation, and allowing any number of custom configurations, consumers could come up with. Network interface is OS level entity, and OS is what should manage it. \
-Working configuration, is tun enabled in Xray config with specific name (e.g. xray0), and OS level configuration to manage "xray0" interface, applying routing and rules on interface up.
-This way consistency of system level routing and rules is ensured from single place of responsibility - the OS itself. \
+By default, enabling the feature will only bring the tun interface up. \
+When configured explicitly, Windows and Linux can also apply interface addresses from `gateway` and on-link routes from `autoSystemRoutingTable`.
+Linux does not configure system DNS from the `dns` field; system DNS remains managed by the OS or distribution-specific network services. \
+For more advanced routing policies or rules, OS level configuration can still manage the named interface (e.g. xray0) when it appears.
+This keeps complex system level routing and rules in a single place of responsibility - the OS itself. \
 Examples of how to achieve this on a simple Linux system (Ubuntu with systemd-networkd) can be found at the end of this README.
 
 Due to this inbound not actually being a proxy, the configuration ignore required listen and port options, and never listen on any port. \

proxy/tun/tun_linux.go

@@ -26,9 +26,10 @@ type LinuxTun struct {
 	options *Config
 	ownsTun bool
 
-	systemRoutes     []netlink.Route
-	routeMonitorStop chan struct{}
-	routeMonitorOnce sync.Once
+	interfaceAddresses []netlink.Addr
+	systemRoutes       []netlink.Route
+	routeMonitorStop   chan struct{}
+	routeMonitorOnce   sync.Once
 }
 
 // LinuxTun implements Tun
@@ -172,7 +173,14 @@ func (t *LinuxTun) Start() error {
 		return err
 	}
 
+	if err := t.setInterfaceAddresses(); err != nil {
+		_ = netlink.LinkSetDown(t.tunLink)
+		return err
+	}
+
 	if err := t.setSystemRoutes(); err != nil {
+		_ = t.unsetInterfaceAddresses()
+		_ = netlink.LinkSetDown(t.tunLink)
 		return err
 	}
 
@@ -193,6 +201,7 @@ func (t *LinuxTun) Close() error {
 	})
 
 	_ = t.unsetSystemRoutes()
+	_ = t.unsetInterfaceAddresses()
 
 	if t.ownsTun {
 		_ = netlink.LinkSetDown(t.tunLink)
@@ -223,6 +232,37 @@ func setinterface(network, address string, fd uintptr, iface *net.Interface) err
 	return unix.BindToDevice(int(fd), iface.Name)
 }
 
+func (t *LinuxTun) setInterfaceAddresses() error {
+	if len(t.options.Gateway) == 0 {
+		return nil
+	}
+	for _, address := range t.options.Gateway {
+		addr, err := netlink.ParseAddr(address)
+		if err != nil {
+			_ = t.unsetInterfaceAddresses()
+			return errors.New("invalid interface address ", address).Base(err)
+		}
+		if err := netlink.AddrAdd(t.tunLink, addr); err != nil {
+			_ = t.unsetInterfaceAddresses()
+			return errors.New("failed to add interface address ", address).Base(err)
+		}
+		t.interfaceAddresses = append(t.interfaceAddresses, *addr)
+	}
+	return nil
+}
+
+func (t *LinuxTun) unsetInterfaceAddresses() error {
+	var errs []error
+	for i := len(t.interfaceAddresses) - 1; i >= 0; i-- {
+		address := t.interfaceAddresses[i]
+		if err := netlink.AddrDel(t.tunLink, &address); err != nil {
+			errs = append(errs, errors.New("failed to delete interface address ", address.String()).Base(err))
+		}
+	}
+	t.interfaceAddresses = nil
+	return errors.Combine(errs...)
+}
+
 func (t *LinuxTun) setSystemRoutes() error {
 	if len(t.options.AutoSystemRoutingTable) == 0 {
 		return nil
@@ -308,36 +348,37 @@ func findOutboundInterface(tunIndex int, fixedName string) (*net.Interface, erro
 		return iface, nil
 	}
 
-	probeIPs := []net.IP{
-		net.ParseIP("8.8.8.8"),
-		net.ParseIP("2001:4860:4860::8888"),
+	for _, family := range []int{
+		netlink.FAMILY_V4,
+		netlink.FAMILY_V6,
+	} {
+		iface, err := findDefaultInterface(family, tunIndex)
+		if err == nil {
+			return iface, nil
+		}
 	}
 
-	for _, ip := range probeIPs {
-		routes, err := netlink.RouteGet(ip)
-		if err != nil || len(routes) == 0 {
-			continue
-		}
-		route := routes[0]
-		if route.LinkIndex == tunIndex {
-			continue
+	return nil, errors.New("no usable outbound interface found")
+}
+
+func findDefaultInterface(family int, tunIndex int) (*net.Interface, error) {
+	routes, err := netlink.RouteList(nil, family)
+	if err != nil {
+		return nil, err
+	}
+
+	var selected *net.Interface
+	selectedMetric := -1
+
+	for _, route := range routes {
+		if route.Dst != nil {
+			ones, _ := route.Dst.Mask.Size()
+			if ones != 0 {
+				continue
+			}
 		}
 
-		link, err := netlink.LinkByIndex(route.LinkIndex)
-		if err != nil {
-			continue
-		}
-		attrs := link.Attrs()
-
-		if attrs.Flags&net.FlagUp == 0 {
-			continue
-		}
-		operState := attrs.OperState
-		if operState != netlink.OperUp && operState != netlink.OperUnknown {
-			continue
-		}
-
-		if route.Src == nil || route.Src.IsLoopback() || route.Src.IsLinkLocalUnicast() {
+		if route.LinkIndex == 0 || route.LinkIndex == tunIndex {
 			continue
 		}
 
@@ -345,8 +386,21 @@ func findOutboundInterface(tunIndex int, fixedName string) (*net.Interface, erro
 		if err != nil {
 			continue
 		}
-		return iface, nil
+
+		if iface.Flags&net.FlagUp == 0 ||
+			iface.Flags&net.FlagLoopback != 0 {
+			continue
+		}
+
+		if selected == nil || route.Priority < selectedMetric {
+			selected = iface
+			selectedMetric = route.Priority
+		}
 	}
 
-	return nil, errors.New("no usable outbound interface found")
+	if selected == nil {
+		return nil, errors.New("physical default route not found")
+	}
+
+	return selected, nil
 }