Refactor(core): with error callback

core/adapter/handler.go

@@ -1,14 +1,8 @@
 package adapter
 
 // TransportHandler is a TCP/UDP connection handler that implements
-// HandleTCPConn and HandleUDPConn methods.
+// HandleTCP and HandleUDP methods.
 type TransportHandler interface {
 	HandleTCP(TCPConn)
 	HandleUDP(UDPConn)
 }
-
-// TCPHandleFunc handles incoming TCP connection.
-type TCPHandleFunc func(TCPConn)
-
-// UDPHandleFunc handles incoming UDP connection.
-type UDPHandleFunc func(UDPConn)

core/stack.go

@@ -13,8 +13,36 @@ import (
 	"gvisor.dev/gvisor/pkg/tcpip/transport/udp"
 )
 
-// CreateStackWithOptions creates *stack.Stack with given options.
-func CreateStackWithOptions(linkEP stack.LinkEndpoint, handler adapter.TransportHandler, opts ...option.Option) (*stack.Stack, error) {
+// Config is the configuration to create *stack.Stack.
+type Config struct {
+	// LinkEndpoints is the interface implemented by
+	// data link layer protocols.
+	LinkEndpoint stack.LinkEndpoint
+
+	// TransportHandler is the handler used by internal
+	// stack to set transport handlers.
+	TransportHandler adapter.TransportHandler
+
+	// ErrorFunc is the function that will be called
+	// when internal stack encounters errors.
+	ErrorFunc func(tcpip.Error)
+
+	// Options are supplement options to apply settings
+	// for the internal stack.
+	Options []option.Option
+}
+
+// CreateStack creates *stack.Stack with given config.
+func CreateStack(cfg *Config) (*stack.Stack, error) {
+	if cfg.ErrorFunc == nil {
+		cfg.ErrorFunc = func(tcpip.Error) {}
+	}
+
+	opts := cfg.Options
+	if len(opts) == 0 {
+		opts = []option.Option{option.WithDefault()}
+	}
+
 	s := stack.New(stack.Options{
 		NetworkProtocols: []stack.NetworkProtocolFactory{
 			ipv4.NewProtocol,
@@ -33,7 +61,7 @@ func CreateStackWithOptions(linkEP stack.LinkEndpoint, handler adapter.Transport
 
 	opts = append(opts,
 		// Create stack NIC and then bind link endpoint to it.
-		withCreatingNIC(nicID, linkEP),
+		withCreatingNIC(nicID, cfg.LinkEndpoint),
 
 		// In the past we did s.AddAddressRange to assign 0.0.0.0/0
 		// onto the interface. We need that to be able to terminate
@@ -63,7 +91,8 @@ func CreateStackWithOptions(linkEP stack.LinkEndpoint, handler adapter.Transport
 		withRouteTable(nicID),
 
 		// Initiate transport protocol (TCP/UDP) with given handler.
-		withTCPHandler(handler.HandleTCP), withUDPHandler(handler.HandleUDP),
+		withTCPHandler(cfg.TransportHandler.HandleTCP, cfg.ErrorFunc),
+		withUDPHandler(cfg.TransportHandler.HandleUDP, cfg.ErrorFunc),
 	)
 
 	for _, opt := range opts {

core/tcp.go

@@ -39,11 +39,22 @@ const (
 	tcpKeepaliveInterval = 30 * time.Second
 )
 
-func withTCPHandler(handle adapter.TCPHandleFunc) option.Option {
+func withTCPHandler(handle func(adapter.TCPConn), callback func(tcpip.Error)) option.Option {
 	return func(s *stack.Stack) error {
 		tcpForwarder := tcp.NewForwarder(s, defaultWndSize, maxConnAttempts, func(r *tcp.ForwarderRequest) {
-			var wq waiter.Queue
-			ep, err := r.CreateEndpoint(&wq)
+			var (
+				wq  waiter.Queue
+				ep  tcpip.Endpoint
+				err tcpip.Error
+			)
+
+			defer func() {
+				if err != nil {
+					callback(err)
+				}
+			}()
+
+			ep, err = r.CreateEndpoint(&wq)
 			if err != nil {
 				// RST: prevent potential half-open TCP connection leak.
 				r.Complete(true)
@@ -51,7 +62,8 @@ func withTCPHandler(handle adapter.TCPHandleFunc) option.Option {
 			}
 			defer r.Complete(false)
 
-			setKeepalive(ep)
+			// TCP Keepalive
+			err = setKeepalive(ep)
 
 			conn := &tcpConn{
 				TCPConn: gonet.NewTCPConn(&wq, ep),

core/udp.go

@@ -4,19 +4,20 @@ import (
 	"github.com/xjasonlyu/tun2socks/v2/core/adapter"
 	"github.com/xjasonlyu/tun2socks/v2/core/option"
 
+	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/adapters/gonet"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 	"gvisor.dev/gvisor/pkg/tcpip/transport/udp"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
 
-func withUDPHandler(handle adapter.UDPHandleFunc) option.Option {
+func withUDPHandler(handle func(adapter.UDPConn), callback func(tcpip.Error)) option.Option {
 	return func(s *stack.Stack) error {
 		udpForwarder := udp.NewForwarder(s, func(r *udp.ForwarderRequest) {
 			var wq waiter.Queue
 			ep, err := r.CreateEndpoint(&wq)
 			if err != nil {
-				// TODO: handler errors in the future.
+				callback(err)
 				return
 			}
 

engine/engine.go

@@ -7,13 +7,13 @@ import (
 	"github.com/xjasonlyu/tun2socks/v2/component/dialer"
 	"github.com/xjasonlyu/tun2socks/v2/core"
 	"github.com/xjasonlyu/tun2socks/v2/core/device"
-	"github.com/xjasonlyu/tun2socks/v2/core/option"
 	_ "github.com/xjasonlyu/tun2socks/v2/dns"
 	"github.com/xjasonlyu/tun2socks/v2/log"
 	"github.com/xjasonlyu/tun2socks/v2/proxy"
 	"github.com/xjasonlyu/tun2socks/v2/stats"
 	"github.com/xjasonlyu/tun2socks/v2/tunnel"
 
+	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 )
 
@@ -169,6 +169,12 @@ func (e *engine) applyStack() (err error) {
 		}
 	}()
 
-	e.stack, err = core.CreateStackWithOptions(e.device, &fakeTunnel{}, option.WithDefault())
+	e.stack, err = core.CreateStack(&core.Config{
+		LinkEndpoint:     e.device,
+		TransportHandler: &fakeTunnel{},
+		ErrorFunc: func(err tcpip.Error) {
+			log.Warnf("[STACK] %s", err)
+		},
+	})
 	return
 }