TUN inbound: Fix log, CanSpliceCopy, tag, sniffing, and port config issues (#5522)

Fixes https://github.com/XTLS/Xray-core/pull/5509#issuecomment-3732488294 & https://github.com/XTLS/Xray-core/pull/5509#issuecomment-3732740897

---------

Co-authored-by: RPRX <63339210+RPRX@users.noreply.github.com>

app/proxyman/inbound/always.go

@@ -9,6 +9,7 @@ import (
 	"github.com/xtls/xray-core/common/mux"
 	"github.com/xtls/xray-core/common/net"
 	"github.com/xtls/xray-core/common/serial"
+	"github.com/xtls/xray-core/common/session"
 	"github.com/xtls/xray-core/core"
 	"github.com/xtls/xray-core/features/policy"
 	"github.com/xtls/xray-core/features/stats"
@@ -52,6 +53,20 @@ type AlwaysOnInboundHandler struct {
 }
 
 func NewAlwaysOnInboundHandler(ctx context.Context, tag string, receiverConfig *proxyman.ReceiverConfig, proxyConfig interface{}) (*AlwaysOnInboundHandler, error) {
+	// Set tag and sniffing config in context before creating proxy
+	// This allows proxies like TUN to access these settings
+	ctx = session.ContextWithInbound(ctx, &session.Inbound{Tag: tag})
+	if receiverConfig.SniffingSettings != nil {
+		ctx = session.ContextWithContent(ctx, &session.Content{
+			SniffingRequest: session.SniffingRequest{
+				Enabled:                        receiverConfig.SniffingSettings.Enabled,
+				OverrideDestinationForProtocol: receiverConfig.SniffingSettings.DestinationOverride,
+				ExcludeForDomain:               receiverConfig.SniffingSettings.DomainsExcluded,
+				MetadataOnly:                   receiverConfig.SniffingSettings.MetadataOnly,
+				RouteOnly:                      receiverConfig.SniffingSettings.RouteOnly,
+			},
+		})
+	}
 	rawProxy, err := common.CreateObject(ctx, proxyConfig)
 	if err != nil {
 		return nil, err

infra/conf/xray.go

@@ -130,7 +130,10 @@ type InboundDetourConfig struct {
 func (c *InboundDetourConfig) Build() (*core.InboundHandlerConfig, error) {
 	receiverSettings := &proxyman.ReceiverConfig{}
 
-	if c.ListenOn == nil {
+	// TUN inbound doesn't need port configuration as it uses network interface instead
+	if strings.ToLower(c.Protocol) == "tun" {
+		// Skip port validation for TUN
+	} else if c.ListenOn == nil {
 		// Listen on anyip, must set PortList
 		if c.PortList == nil {
 			return nil, errors.New("Listen on AnyIP but no Port(s) set in InboundDetour.")

proxy/tun/handler.go

@@ -7,6 +7,7 @@ import (
 	"github.com/xtls/xray-core/common/buf"
 	c "github.com/xtls/xray-core/common/ctx"
 	"github.com/xtls/xray-core/common/errors"
+	"github.com/xtls/xray-core/common/log"
 	"github.com/xtls/xray-core/common/net"
 	"github.com/xtls/xray-core/common/protocol"
 	"github.com/xtls/xray-core/common/session"
@@ -19,11 +20,13 @@ import (
 
 // Handler is managing object that tie together tun interface, ip stack and dispatch connections to the routing
 type Handler struct {
-	ctx           context.Context
-	config        *Config
-	stack         Stack
-	policyManager policy.Manager
-	dispatcher    routing.Dispatcher
+	ctx             context.Context
+	config          *Config
+	stack           Stack
+	policyManager   policy.Manager
+	dispatcher      routing.Dispatcher
+	tag             string
+	sniffingRequest session.SniffingRequest
 }
 
 // ConnectionHandler interface with the only method that stack is going to push new connections to
@@ -43,6 +46,14 @@ func (t *Handler) policy() policy.Session {
 func (t *Handler) Init(ctx context.Context, pm policy.Manager, dispatcher routing.Dispatcher) error {
 	var err error
 
+	// Retrieve tag and sniffing config from context (set by AlwaysOnInboundHandler)
+	if inbound := session.InboundFromContext(ctx); inbound != nil {
+		t.tag = inbound.Tag
+	}
+	if content := session.ContentFromContext(ctx); content != nil {
+		t.sniffingRequest = content.SniffingRequest
+	}
+
 	t.ctx = core.ToBackgroundDetachedContext(ctx)
 	t.policyManager = pm
 	t.dispatcher = dispatcher
@@ -93,29 +104,38 @@ func (t *Handler) Init(ctx context.Context, pm policy.Manager, dispatcher routin
 func (t *Handler) HandleConnection(conn net.Conn, destination net.Destination) {
 	sid := session.NewID()
 	ctx := c.ContextWithID(t.ctx, sid)
-	errors.LogInfo(ctx, "processing connection from: ", conn.RemoteAddr())
 
-	inbound := session.Inbound{}
-	inbound.Name = "tun"
-	inbound.CanSpliceCopy = 1
-	inbound.Source = net.DestinationFromAddr(conn.RemoteAddr())
-	inbound.User = &protocol.MemoryUser{
-		Level: t.config.UserLevel,
+	inbound := session.Inbound{
+		Name:          "tun",
+		Tag:           t.tag,
+		CanSpliceCopy: 3,
+		Source:        net.DestinationFromAddr(conn.RemoteAddr()),
+		User: &protocol.MemoryUser{
+			Level: t.config.UserLevel,
+		},
 	}
 
 	ctx = session.ContextWithInbound(ctx, &inbound)
+	ctx = session.ContextWithContent(ctx, &session.Content{
+		SniffingRequest: t.sniffingRequest,
+	})
 	ctx = session.SubContextFromMuxInbound(ctx)
 
+	ctx = log.ContextWithAccessMessage(ctx, &log.AccessMessage{
+		From:   inbound.Source,
+		To:     destination,
+		Status: log.AccessAccepted,
+		Reason: "",
+	})
+	errors.LogInfo(ctx, "processing TCP from ", conn.RemoteAddr(), " to ", destination)
+
 	link := &transport.Link{
 		Reader: &buf.TimeoutWrapperReader{Reader: buf.NewReader(conn)},
 		Writer: buf.NewWriter(conn),
 	}
 	if err := t.dispatcher.DispatchLink(ctx, destination, link); err != nil {
 		errors.LogError(ctx, errors.New("connection closed").Base(err))
-		return
 	}
-
-	errors.LogInfo(ctx, "connection completed")
 }
 
 // Network implements proxy.Inbound

proxy/tun/udp_fullcone.go

@@ -10,6 +10,7 @@ import (
 	"github.com/xtls/xray-core/common/buf"
 	c "github.com/xtls/xray-core/common/ctx"
 	"github.com/xtls/xray-core/common/errors"
+	"github.com/xtls/xray-core/common/log"
 	"github.com/xtls/xray-core/common/net"
 	"github.com/xtls/xray-core/common/protocol"
 	"github.com/xtls/xray-core/common/session"
@@ -100,12 +101,23 @@ func (u *udpConnectionHandler) HandlePacket(src net.Destination, dst net.Destina
 
 			inbound := &session.Inbound{
 				Name:          "tun",
+				Tag:           u.handler.tag,
 				Source:        src,
-				CanSpliceCopy: 1,
+				CanSpliceCopy: 3,
 				User:          &protocol.MemoryUser{Level: u.handler.config.UserLevel},
 			}
 			ctx = session.ContextWithInbound(c.ContextWithID(ctx, session.NewID()), inbound)
+			ctx = session.ContextWithContent(ctx, &session.Content{
+				SniffingRequest: u.handler.sniffingRequest,
+			})
 			ctx = session.SubContextFromMuxInbound(ctx)
+			ctx = log.ContextWithAccessMessage(ctx, &log.AccessMessage{
+				From:   src,
+				To:     dst,
+				Status: log.AccessAccepted,
+				Reason: "",
+			})
+			errors.LogInfo(ctx, "processing UDP from ", src, " to ", dst)
 			link := &transport.Link{
 				Reader: &buf.TimeoutWrapperReader{Reader: conn.reader},
 				// reverse source and destination, indicating the packets to write are going in the other