feat: enable fwmark (SO_MARK) for outgoing sockets

cmd/outline-ss-server/config.go

@@ -24,18 +24,24 @@ import (
 type ServiceConfig struct {
 	Listeners []ListenerConfig
 	Keys      []KeyConfig
+	Dialer    DialerConfig
 }
 
 type ListenerType string
 
 const listenerTypeTCP ListenerType = "tcp"
+
 const listenerTypeUDP ListenerType = "udp"
 
 type ListenerConfig struct {
 	Type    ListenerType
 	Address string
 }
 
+type DialerConfig struct {
+	Fwmark uint
+}
+
 type KeyConfig struct {
 	ID     string
 	Cipher string

cmd/outline-ss-server/config_example.yml

@@ -21,19 +21,22 @@ services:
       - type: udp
         address: "[::]:9000"
     keys:
-        - id: user-0
-          cipher: chacha20-ietf-poly1305
-          secret: Secret0
-        - id: user-1
-          cipher: chacha20-ietf-poly1305
-          secret: Secret1
-
+      - id: user-0
+        cipher: chacha20-ietf-poly1305
+        secret: Secret0
+      - id: user-1
+        cipher: chacha20-ietf-poly1305
+        secret: Secret1
+    dialer:
+      # fwmark can be used in conjunction with other Linux networking features like cgroups, network namespaces, and TC (Traffic Control) for sophisticated network management.
+      # Value of 0 disables fwmark (SO_MARK) (Linux Only)
+      fwmark: 0
   - listeners:
       - type: tcp
         address: "[::]:9001"
       - type: udp
         address: "[::]:9001"
     keys:
-        - id: user-2
-          cipher: chacha20-ietf-poly1305
-          secret: Secret2
+      - id: user-2
+        cipher: chacha20-ietf-poly1305
+        secret: Secret2

cmd/outline-ss-server/main.go

@@ -31,16 +31,20 @@ import (
 
 	"github.com/Jigsaw-Code/outline-sdk/transport"
 	"github.com/Jigsaw-Code/outline-sdk/transport/shadowsocks"
-	"github.com/Jigsaw-Code/outline-ss-server/ipinfo"
-	"github.com/Jigsaw-Code/outline-ss-server/service"
 	"github.com/lmittmann/tint"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"golang.org/x/term"
+
+	"github.com/Jigsaw-Code/outline-ss-server/ipinfo"
+	onet "github.com/Jigsaw-Code/outline-ss-server/net"
+	"github.com/Jigsaw-Code/outline-ss-server/service"
 )
 
-var logLevel = new(slog.LevelVar) // Info by default
-var logHandler slog.Handler
+var (
+	logLevel   = new(slog.LevelVar) // Info by default
+	logHandler slog.Handler
+)
 
 // Set by goreleaser default ldflags. See https://goreleaser.com/customization/build/
 var version = "dev"
@@ -120,30 +124,32 @@ func newCipherListFromConfig(config ServiceConfig) (service.CipherList, error) {
 	return ciphers, nil
 }
 
-func (s *SSServer) NewShadowsocksStreamHandler(ciphers service.CipherList) service.StreamHandler {
+func (s *SSServer) NewShadowsocksStreamHandler(ciphers service.CipherList, dialer transport.StreamDialer) service.StreamHandler {
 	authFunc := service.NewShadowsocksStreamAuthenticator(ciphers, &s.replayCache, s.m.tcpServiceMetrics)
 	// TODO: Register initial data metrics at zero.
-	return service.NewStreamHandler(authFunc, tcpReadTimeout)
+	return service.NewStreamHandler(authFunc, tcpReadTimeout, dialer)
 }
 
-func (s *SSServer) NewShadowsocksPacketHandler(ciphers service.CipherList) service.PacketHandler {
-	return service.NewPacketHandler(s.natTimeout, ciphers, s.m, s.m.udpServiceMetrics)
+func (s *SSServer) NewShadowsocksPacketHandler(ciphers service.CipherList, dialer service.UDPDialer) service.PacketHandler {
+	return service.NewPacketHandler(s.natTimeout, ciphers, s.m, s.m.udpServiceMetrics, dialer)
 }
 
 func (s *SSServer) NewShadowsocksStreamHandlerFromConfig(config ServiceConfig) (service.StreamHandler, error) {
 	ciphers, err := newCipherListFromConfig(config)
 	if err != nil {
 		return nil, err
 	}
-	return s.NewShadowsocksStreamHandler(ciphers), nil
+	dialer := service.MakeValidatingTCPStreamDialer(onet.RequirePublicIP, config.Dialer.Fwmark)
+	return s.NewShadowsocksStreamHandler(ciphers, dialer), nil
 }
 
 func (s *SSServer) NewShadowsocksPacketHandlerFromConfig(config ServiceConfig) (service.PacketHandler, error) {
 	ciphers, err := newCipherListFromConfig(config)
 	if err != nil {
 		return nil, err
 	}
-	return s.NewShadowsocksPacketHandler(ciphers), nil
+	dialer := service.MakeTargetPacketListener(config.Dialer.Fwmark)
+	return s.NewShadowsocksPacketHandler(ciphers, dialer), nil
 }
 
 type listenerSet struct {
@@ -243,7 +249,8 @@ func (s *SSServer) runConfig(config Config) (func() error, error) {
 				ciphers := service.NewCipherList()
 				ciphers.Update(cipherList)
 
-				sh := s.NewShadowsocksStreamHandler(ciphers)
+				tcpDialer := service.MakeValidatingTCPStreamDialer(onet.RequirePublicIP, 0)
+				sh := s.NewShadowsocksStreamHandler(ciphers, tcpDialer)
 				ln, err := lnSet.ListenStream(addr)
 				if err != nil {
 					return err
@@ -259,7 +266,8 @@ func (s *SSServer) runConfig(config Config) (func() error, error) {
 					return err
 				}
 				slog.Info("UDP service started.", "address", pc.LocalAddr().String())
-				ph := s.NewShadowsocksPacketHandler(ciphers)
+				udpDialer := service.MakeTargetPacketListener(0)
+				ph := s.NewShadowsocksPacketHandler(ciphers, udpDialer)
 				go ph.Handle(pc)
 			}
 
@@ -275,7 +283,12 @@ func (s *SSServer) runConfig(config Config) (func() error, error) {
 						if err != nil {
 							return err
 						}
-						slog.Info("TCP service started.", "address", ln.Addr().String())
+						slog.Info("TCP service started.", "address", ln.Addr().String(), "fwmark", func() any {
+							if serviceConfig.Dialer.Fwmark == 0 {
+								return "disabled"
+							}
+							return serviceConfig.Dialer.Fwmark
+						}())
 						if sh == nil {
 							sh, err = s.NewShadowsocksStreamHandlerFromConfig(serviceConfig)
 							if err != nil {
@@ -291,7 +304,12 @@ func (s *SSServer) runConfig(config Config) (func() error, error) {
 						if err != nil {
 							return err
 						}
-						slog.Info("UDP service started.", "address", pc.LocalAddr().String())
+						slog.Info("UDP service started.", "address", pc.LocalAddr().String(), "fwmark", func() any {
+							if serviceConfig.Dialer.Fwmark == 0 {
+								return "disabled"
+							}
+							return serviceConfig.Dialer.Fwmark
+						}())
 						if ph == nil {
 							ph, err = s.NewShadowsocksPacketHandlerFromConfig(serviceConfig)
 							if err != nil {

internal/integration_test/integration_test.go

@@ -27,15 +27,21 @@ import (
 
 	"github.com/Jigsaw-Code/outline-sdk/transport"
 	"github.com/Jigsaw-Code/outline-sdk/transport/shadowsocks"
-	"github.com/Jigsaw-Code/outline-ss-server/service"
-	"github.com/Jigsaw-Code/outline-ss-server/service/metrics"
 	logging "github.com/op/go-logging"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+
+	onet "github.com/Jigsaw-Code/outline-ss-server/net"
+	"github.com/Jigsaw-Code/outline-ss-server/service"
+	"github.com/Jigsaw-Code/outline-ss-server/service/metrics"
 )
 
 const maxUDPPacketSize = 64 * 1024
 
+var udpDefaultDialer = service.MakeTargetPacketListener(0)
+
+var tcpDefaultDialer = service.MakeValidatingTCPStreamDialer(onet.RequirePublicIP, 0)
+
 func init() {
 	logging.SetLevel(logging.INFO, "")
 }
@@ -132,8 +138,7 @@ func TestTCPEcho(t *testing.T) {
 	const testTimeout = 200 * time.Millisecond
 	testMetrics := &statusMetrics{}
 	authFunc := service.NewShadowsocksStreamAuthenticator(cipherList, &replayCache, &fakeShadowsocksMetrics{})
-	handler := service.NewStreamHandler(authFunc, testTimeout)
-	handler.SetTargetDialer(&transport.TCPDialer{})
+	handler := service.NewStreamHandler(authFunc, testTimeout, &transport.TCPDialer{})
 	done := make(chan struct{})
 	go func() {
 		service.StreamServe(
@@ -183,8 +188,7 @@ func TestTCPEcho(t *testing.T) {
 	echoRunning.Wait()
 }
 
-type fakeShadowsocksMetrics struct {
-}
+type fakeShadowsocksMetrics struct{}
 
 var _ service.ShadowsocksConnMetrics = (*fakeShadowsocksMetrics)(nil)
 
@@ -212,7 +216,7 @@ func TestRestrictedAddresses(t *testing.T) {
 	const testTimeout = 200 * time.Millisecond
 	testMetrics := &statusMetrics{}
 	authFunc := service.NewShadowsocksStreamAuthenticator(cipherList, nil, &fakeShadowsocksMetrics{})
-	handler := service.NewStreamHandler(authFunc, testTimeout)
+	handler := service.NewStreamHandler(authFunc, testTimeout, tcpDefaultDialer)
 	done := make(chan struct{})
 	go func() {
 		service.StreamServe(
@@ -275,9 +279,11 @@ var _ service.UDPConnMetrics = (*fakeUDPConnMetrics)(nil)
 func (m *fakeUDPConnMetrics) AddPacketFromClient(status string, clientProxyBytes, proxyTargetBytes int64) {
 	m.up = append(m.up, udpRecord{m.clientAddr, m.accessKey, status, clientProxyBytes, proxyTargetBytes})
 }
+
 func (m *fakeUDPConnMetrics) AddPacketFromTarget(status string, targetProxyBytes, proxyClientBytes int64) {
 	m.down = append(m.down, udpRecord{m.clientAddr, m.accessKey, status, targetProxyBytes, proxyClientBytes})
 }
+
 func (m *fakeUDPConnMetrics) RemoveNatEntry() {
 	// Not tested because it requires waiting for a long timeout.
 }
@@ -311,7 +317,7 @@ func TestUDPEcho(t *testing.T) {
 		t.Fatal(err)
 	}
 	testMetrics := &fakeUDPMetrics{}
-	proxy := service.NewPacketHandler(time.Hour, cipherList, testMetrics, &fakeShadowsocksMetrics{})
+	proxy := service.NewPacketHandler(time.Hour, cipherList, testMetrics, &fakeShadowsocksMetrics{}, udpDefaultDialer)
 	proxy.SetTargetIPValidator(allowAll)
 	done := make(chan struct{})
 	go func() {
@@ -401,8 +407,7 @@ func BenchmarkTCPThroughput(b *testing.B) {
 	const testTimeout = 200 * time.Millisecond
 	testMetrics := &service.NoOpTCPConnMetrics{}
 	authFunc := service.NewShadowsocksStreamAuthenticator(cipherList, nil, &fakeShadowsocksMetrics{})
-	handler := service.NewStreamHandler(authFunc, testTimeout)
-	handler.SetTargetDialer(&transport.TCPDialer{})
+	handler := service.NewStreamHandler(authFunc, testTimeout, &transport.TCPDialer{})
 	done := make(chan struct{})
 	go func() {
 		service.StreamServe(
@@ -468,8 +473,7 @@ func BenchmarkTCPMultiplexing(b *testing.B) {
 	const testTimeout = 200 * time.Millisecond
 	testMetrics := &service.NoOpTCPConnMetrics{}
 	authFunc := service.NewShadowsocksStreamAuthenticator(cipherList, &replayCache, &fakeShadowsocksMetrics{})
-	handler := service.NewStreamHandler(authFunc, testTimeout)
-	handler.SetTargetDialer(&transport.TCPDialer{})
+	handler := service.NewStreamHandler(authFunc, testTimeout, &transport.TCPDialer{})
 	done := make(chan struct{})
 	go func() {
 		service.StreamServe(
@@ -544,7 +548,7 @@ func BenchmarkUDPEcho(b *testing.B) {
 	if err != nil {
 		b.Fatal(err)
 	}
-	proxy := service.NewPacketHandler(time.Hour, cipherList, &service.NoOpUDPMetrics{}, &fakeShadowsocksMetrics{})
+	proxy := service.NewPacketHandler(time.Hour, cipherList, &service.NoOpUDPMetrics{}, &fakeShadowsocksMetrics{}, udpDefaultDialer)
 	proxy.SetTargetIPValidator(allowAll)
 	done := make(chan struct{})
 	go func() {
@@ -588,7 +592,7 @@ func BenchmarkUDPManyKeys(b *testing.B) {
 	if err != nil {
 		b.Fatal(err)
 	}
-	proxy := service.NewPacketHandler(time.Hour, cipherList, &service.NoOpUDPMetrics{}, &fakeShadowsocksMetrics{})
+	proxy := service.NewPacketHandler(time.Hour, cipherList, &service.NoOpUDPMetrics{}, &fakeShadowsocksMetrics{}, udpDefaultDialer)
 	proxy.SetTargetIPValidator(allowAll)
 	done := make(chan struct{})
 	go func() {

service/socketopts_linux.go

@@ -0,0 +1,30 @@
+// Copyright 2018 Jigsaw Operations LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build linux
+
+package service
+
+import (
+	"os"
+	"syscall"
+)
+
+func SetFwmark(fd uintptr, fwmark uint) error {
+	err := syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_MARK, int(fwmark))
+	if err != nil {
+		os.NewSyscallError("failed to set fwmark for socket", err)
+	}
+	return nil
+}

service/tcp.go

@@ -25,14 +25,14 @@ import (
 	"net"
 	"net/netip"
 	"sync"
-	"syscall"
 	"time"
 
 	"github.com/Jigsaw-Code/outline-sdk/transport"
 	"github.com/Jigsaw-Code/outline-sdk/transport/shadowsocks"
+	"github.com/shadowsocks/go-shadowsocks2/socks"
+
 	onet "github.com/Jigsaw-Code/outline-ss-server/net"
 	"github.com/Jigsaw-Code/outline-ss-server/service/metrics"
-	"github.com/shadowsocks/go-shadowsocks2/socks"
 )
 
 // TCPConnMetrics is used to report metrics on TCP connections.
@@ -158,23 +158,14 @@ type streamHandler struct {
 }
 
 // NewStreamHandler creates a StreamHandler
-func NewStreamHandler(authenticate StreamAuthenticateFunc, timeout time.Duration) StreamHandler {
+func NewStreamHandler(authenticate StreamAuthenticateFunc, timeout time.Duration, dialer transport.StreamDialer) StreamHandler {
 	return &streamHandler{
 		readTimeout:  timeout,
 		authenticate: authenticate,
-		dialer:       defaultDialer,
+		dialer:       dialer,
 	}
 }
 
-var defaultDialer = makeValidatingTCPStreamDialer(onet.RequirePublicIP)
-
-func makeValidatingTCPStreamDialer(targetIPValidator onet.TargetIPValidator) transport.StreamDialer {
-	return &transport.TCPDialer{Dialer: net.Dialer{Control: func(network, address string, c syscall.RawConn) error {
-		ip, _, _ := net.SplitHostPort(address)
-		return targetIPValidator(net.ParseIP(ip))
-	}}}
-}
-
 // StreamHandler is a handler that handles stream connections.
 type StreamHandler interface {
 	Handle(ctx context.Context, conn transport.StreamConn, connMetrics TCPConnMetrics)
@@ -377,6 +368,8 @@ type NoOpTCPConnMetrics struct{}
 var _ TCPConnMetrics = (*NoOpTCPConnMetrics)(nil)
 
 func (m *NoOpTCPConnMetrics) AddAuthenticated(accessKey string) {}
+
 func (m *NoOpTCPConnMetrics) AddClosed(status string, data metrics.ProxyMetrics, duration time.Duration) {
 }
+
 func (m *NoOpTCPConnMetrics) AddProbe(status, drainResult string, clientProxyBytes int64) {}