tcp-brutal

infra/conf/transport_internet.go

@@ -112,6 +112,8 @@ func (c *KCPConfig) Build() (proto.Message, error) {
 type TCPConfig struct {
 	HeaderConfig        json.RawMessage `json:"header"`
 	AcceptProxyProtocol bool            `json:"acceptProxyProtocol"`
+	Rate                uint64          `json:"rate"`
+	Cwnd                uint32          `json:"cwnd"`
 }
 
 // Build implements Buildable.
@@ -131,6 +133,8 @@ func (c *TCPConfig) Build() (proto.Message, error) {
 	if c.AcceptProxyProtocol {
 		config.AcceptProxyProtocol = c.AcceptProxyProtocol
 	}
+	config.Rate = c.Rate
+	config.Cwnd = c.Cwnd
 	return config, nil
 }
 

transport/internet/tcp/config.proto

@@ -12,4 +12,6 @@ message Config {
   reserved 1;
   xray.common.serial.TypedMessage header_settings = 2;
   bool accept_proxy_protocol = 3;
+  uint64 rate = 4;
+  uint32 cwnd = 5;
 }

transport/internet/tcp/hub.go

@@ -108,6 +108,12 @@ func (v *Listener) keepAccepting() {
 			}
 			continue
 		}
+		if v.config.Rate > 0 {
+			err := SetBrutalRate(conn, v.config.Rate, v.config.Cwnd)
+			if err != nil {
+				errors.LogDebugInner(context.Background(), err, "failed to apply socket options to incoming connection")
+			}
+		}
 		go func() {
 			if v.tlsConfig != nil {
 				conn = tls.Server(conn, v.tlsConfig)

transport/internet/tcp/sockopt_darwin.go

@@ -24,3 +24,7 @@ func GetOriginalDestination(conn stat.Connection) (net.Destination, error) {
 	}
 	return dest, nil
 }
+
+func SetBrutalRate(conn stat.Connection, rate uint64, cwnd uint32) error {
+	return nil
+}

transport/internet/tcp/sockopt_freebsd.go

@@ -24,3 +24,7 @@ func GetOriginalDestination(conn stat.Connection) (net.Destination, error) {
 	}
 	return dest, nil
 }
+
+func SetBrutalRate(conn stat.Connection, rate uint64, cwnd uint32) error {
+	return nil
+}

transport/internet/tcp/sockopt_linux.go

@@ -5,6 +5,7 @@ package tcp
 
 import (
 	"context"
+	"encoding/binary"
 	"syscall"
 	"unsafe"
 
@@ -50,3 +51,36 @@ func GetOriginalDestination(conn stat.Connection) (net.Destination, error) {
 	}
 	return dest, nil
 }
+
+func SetBrutalRate(conn stat.Connection, rate uint64, cwnd uint32) error {
+	sys, ok := conn.(syscall.Conn)
+	if !ok {
+		return errors.New("unable to get syscall.Conn")
+	}
+	sysConn, err := sys.SyscallConn()
+	if err != nil {
+		return errors.New("failed to get sys fd").Base(err)
+	}
+	err = sysConn.Control(func(fd uintptr) {
+		if err := syscall.SetsockoptString(int(fd), syscall.IPPROTO_TCP, syscall.TCP_CONGESTION, "brutal"); err != nil {
+			errors.LogDebugInner(context.Background(), err, "failed to set CustomSockoptString ", syscall.TCP_CONGESTION, " ", "brutal")
+			return
+		}
+
+		if cwnd == 0 {
+			cwnd = 15
+		}
+
+		buf := make([]byte, 16)
+		binary.LittleEndian.PutUint64(buf[0:], rate)
+		binary.LittleEndian.PutUint32(buf[8:], cwnd)
+		if err := syscall.SetsockoptString(int(fd), syscall.IPPROTO_TCP, 23301, string(buf)); err != nil {
+			errors.LogDebugInner(context.Background(), err, "failed to set CustomSockoptString 23301 ", buf)
+			return
+		}
+	})
+	if err != nil {
+		return errors.New("failed to control connection").Base(err)
+	}
+	return nil
+}

transport/internet/tcp/sockopt_linux_test.go

@@ -4,9 +4,13 @@
 package tcp_test
 
 import (
+	"bytes"
 	"context"
+	"encoding/binary"
+	"fmt"
 	"strings"
 	"testing"
+	unsafe "unsafe"
 
 	"github.com/xtls/xray-core/common"
 	"github.com/xtls/xray-core/testing/servers/tcp"
@@ -31,3 +35,31 @@ func TestGetOriginalDestination(t *testing.T) {
 		t.Error("unexpected state")
 	}
 }
+
+func TestSockoptParams(t *testing.T) {
+	type BrutalParams struct {
+		rate      uint64
+		cwnd_gain uint32
+	}
+
+	params := BrutalParams{
+		rate:      15 * 1024 * 1024 / 8,
+		cwnd_gain: 15,
+	}
+
+	raw := unsafe.Slice(
+		(*byte)(unsafe.Pointer(&params)),
+		unsafe.Sizeof(params),
+	)
+
+	buf := make([]byte, 16)
+	binary.LittleEndian.PutUint64(buf, 15*1024*1024/8)
+	binary.LittleEndian.PutUint32(buf[8:], 15)
+
+	fmt.Println(len(raw), raw)
+	fmt.Println(len(buf), buf)
+
+	if !bytes.Equal(raw, buf) {
+		t.Fatal("!bytes.Equal(raw, buf)")
+	}
+}

transport/internet/tcp/sockopt_other.go

@@ -11,3 +11,7 @@ import (
 func GetOriginalDestination(conn stat.Connection) (net.Destination, error) {
 	return net.Destination{}, nil
 }
+
+func SetBrutalRate(conn stat.Connection, rate uint64, cwnd uint32) error {
+	return nil
+}