Feature: cli tcp options

core/option/option.go

@@ -159,6 +159,17 @@ func WithICMPLimit(limit rate.Limit) Option {
 	}
 }
 
+// WithTCPSendBufferSize sets default the send buffer size for TCP.
+func WithTCPSendBufferSize(size int) Option {
+	return func(s *stack.Stack) error {
+		sndOpt := tcpip.TCPSendBufferSizeRangeOption{Min: tcpMinBufferSize, Default: size, Max: tcpMaxBufferSize}
+		if err := s.SetTransportProtocolOption(tcp.ProtocolNumber, &sndOpt); err != nil {
+			return fmt.Errorf("set TCP send buffer size range: %s", err)
+		}
+		return nil
+	}
+}
+
 // WithTCPSendBufferSizeRange sets the send buffer size range for TCP.
 func WithTCPSendBufferSizeRange(a, b, c int) Option {
 	return func(s *stack.Stack) error {
@@ -170,6 +181,17 @@ func WithTCPSendBufferSizeRange(a, b, c int) Option {
 	}
 }
 
+// WithTCPReceiveBufferSize sets the default receive buffer size for TCP.
+func WithTCPReceiveBufferSize(size int) Option {
+	return func(s *stack.Stack) error {
+		rcvOpt := tcpip.TCPReceiveBufferSizeRangeOption{Min: tcpMinBufferSize, Default: size, Max: tcpMaxBufferSize}
+		if err := s.SetTransportProtocolOption(tcp.ProtocolNumber, &rcvOpt); err != nil {
+			return fmt.Errorf("set TCP receive buffer size range: %s", err)
+		}
+		return nil
+	}
+}
+
 // WithTCPReceiveBufferSizeRange sets the receive buffer size range for TCP.
 func WithTCPReceiveBufferSizeRange(a, b, c int) Option {
 	return func(s *stack.Stack) error {

engine/engine.go

@@ -8,12 +8,14 @@ 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/engine/mirror"
 	"github.com/xjasonlyu/tun2socks/v2/log"
 	"github.com/xjasonlyu/tun2socks/v2/proxy"
 	"github.com/xjasonlyu/tun2socks/v2/restapi"
 	"github.com/xjasonlyu/tun2socks/v2/tunnel"
 
+	units "github.com/docker/go-units"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 )
@@ -156,12 +158,34 @@ func netstack(k *Key) (err error) {
 		return
 	}
 
+	var opts []option.Option
+	if k.TCPModerateReceiveBuffer {
+		opts = append(opts, option.WithTCPModerateReceiveBuffer(true))
+	}
+
+	if k.TCPSendBufferSize != "" {
+		size, err := units.RAMInBytes(k.TCPSendBufferSize)
+		if err != nil {
+			return err
+		}
+		opts = append(opts, option.WithTCPSendBufferSize(int(size)))
+	}
+
+	if k.TCPReceiveBufferSize != "" {
+		size, err := units.RAMInBytes(k.TCPReceiveBufferSize)
+		if err != nil {
+			return err
+		}
+		opts = append(opts, option.WithTCPReceiveBufferSize(int(size)))
+	}
+
 	if _defaultStack, err = core.CreateStack(&core.Config{
 		LinkEndpoint:     _defaultDevice,
 		TransportHandler: &mirror.Tunnel{},
 		PrintFunc: func(format string, v ...any) {
 			log.Warnf("[STACK] %s", fmt.Sprintf(format, v...))
 		},
+		Options: opts,
 	}); err != nil {
 		return
 	}

engine/key.go

@@ -9,4 +9,7 @@ type Key struct {
 	Device                   string `yaml:"device"`
 	LogLevel                 string `yaml:"loglevel"`
 	Interface                string `yaml:"interface"`
+	TCPModerateReceiveBuffer bool   `yaml:"tcp-moderate-receive-buffer"`
+	TCPSendBufferSize        string `yaml:"tcp-send-buffer-size"`
+	TCPReceiveBufferSize     string `yaml:"tcp-receive-buffer-size"`
 }

main.go

@@ -24,7 +24,6 @@ var (
 )
 
 func init() {
-	flag.BoolVar(&versionFlag, "version", false, "Show version and then quit")
 	flag.IntVar(&key.Mark, "fwmark", 0, "Set firewall MARK (Linux only)")
 	flag.IntVar(&key.MTU, "mtu", 0, "Set device maximum transmission unit (MTU)")
 	flag.IntVar(&key.UDPTimeout, "udp-timeout", 0, "Set timeout for each UDP session")
@@ -34,6 +33,10 @@ func init() {
 	flag.StringVar(&key.LogLevel, "loglevel", "info", "Log level [debug|info|warning|error|silent]")
 	flag.StringVar(&key.Proxy, "proxy", "", "Use this proxy [protocol://]host[:port]")
 	flag.StringVar(&key.RestAPI, "restapi", "", "HTTP statistic server listen address")
+	flag.StringVar(&key.TCPSendBufferSize, "tcp-sndbuf", "", "Set TCP send buffer size for stack")
+	flag.StringVar(&key.TCPReceiveBufferSize, "tcp-rcvbuf", "", "Set TCP receive buffer size for stack")
+	flag.BoolVar(&key.TCPModerateReceiveBuffer, "tcp-auto-tuning", false, "Enable TCP receive buffer auto-tuning")
+	flag.BoolVar(&versionFlag, "version", false, "Show version and then quit")
 	flag.Parse()
 }