Allow firewall marking packets on Linux (#436)

client/cli/base.go

@@ -112,6 +112,7 @@ func reloadConfig(configPtr *string, client *clients.Client) error {
 		}
 		client.SetLocalFeature(feat, en)
 	}
+	client.FirewallMark = config.FirewallMark
 	client.SetDefaultGateway = config.Tunnel.SetDefaultGateway
 	client.ServerURL = dest
 	client.InterfaceConfig = &config.Interface

client/cli/client.example.yml

@@ -12,6 +12,8 @@ interface:
   persist: false
   component-id: root\tap0901 # Windows only. Defaults: root\tap0901 or tap0901
 
+firewall-mark: 0 # Linux only. Set to positive integer to mark packets with this value in the firewall
+
 scripts:
   # These scripts get run as "args... operation subnet interface"
   # Pass in an array, first argument is the executable, further arguments

client/cli/config.go

@@ -23,7 +23,8 @@ type Config struct {
 		Features          features.Config       `yaml:"features"`
 	} `yaml:"tunnel"`
 
-	Interface iface.InterfaceConfig `yaml:"interface"`
+	Interface    iface.InterfaceConfig `yaml:"interface"`
+	FirewallMark int                   `yaml:"firewall-mark"`
 
 	Scripts shared.EventConfig `yaml:"scripts"`
 

client/clients/base.go

@@ -23,6 +23,7 @@ type Client struct {
 	ProxyURL           *url.URL
 	ServerURL          *url.URL
 	Headers            http.Header
+	FirewallMark       int
 	SetDefaultGateway  bool
 	SocketConfigurator sockets.SocketConfigurator
 	InterfaceConfig    *iface.InterfaceConfig

client/clients/connection.go

@@ -3,6 +3,7 @@ package clients
 import (
 	"crypto/tls"
 	"fmt"
+	"net"
 	"net/http"
 	"net/url"
 	"strings"
@@ -28,6 +29,13 @@ func (c *Client) GetServerURL() *url.URL {
 	return c.ServerURL
 }
 
+func (c *Client) EnhanceConn(conn net.Conn) error {
+	if c.FirewallMark <= 0 {
+		return nil
+	}
+	return setFirewallMark(conn, c.FirewallMark)
+}
+
 func (c *Client) RegisterDefaultConnectors() {
 	c.registerConnector(connectors.NewWebSocketConnector())
 	c.registerConnector(connectors.NewWebTransportConnector())

client/clients/connection_linux.go

@@ -0,0 +1,52 @@
+//go:build linux
+
+package clients
+
+import (
+	"crypto/tls"
+	"errors"
+	"log"
+	"net"
+	"syscall"
+
+	"golang.org/x/sys/unix"
+)
+
+const fwmarkIoctl int = 36 /* unix.SO_MARK */
+
+var ErrUnknownConnType = errors.New("not a known conn type")
+
+func setFirewallMark(conn net.Conn, mark int) error {
+	var err error
+	var syscallConn syscall.Conn
+
+	switch typedConn := conn.(type) {
+	case syscall.Conn:
+		syscallConn = typedConn
+	case *tls.Conn:
+		return setFirewallMark(typedConn.NetConn(), mark)
+	default:
+		log.Printf("Unknown conn type: %T (%v)", typedConn, typedConn)
+		err = ErrUnknownConnType
+	}
+
+	if err != nil {
+		return err
+	}
+
+	var operr error
+	fd, err := syscallConn.SyscallConn()
+	if err != nil {
+		return err
+	}
+
+	err = fd.Control(func(fd uintptr) {
+		operr = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, fwmarkIoctl, int(mark))
+	})
+
+	if err == nil {
+		return operr
+	}
+
+	return err
+}

client/clients/connection_other.go

@@ -0,0 +1,11 @@
+//go:build !linux
+
+package clients
+
+import (
+	"net"
+)
+
+func setFirewallMark(conn net.Conn, mark int) error {
+	return nil
+}

client/connectors/base.go

@@ -2,6 +2,7 @@ package connectors
 
 import (
 	"crypto/tls"
+	"net"
 	"net/http"
 	"net/url"
 
@@ -18,4 +19,5 @@ type SocketConnectorConfig interface {
 	GetTLSConfig() *tls.Config
 	GetHeaders() http.Header
 	GetServerURL() *url.URL
+	EnhanceConn(conn net.Conn) error
 }

client/connectors/websocket.go

@@ -57,6 +57,11 @@ func (c *WebSocketConnector) Dial(config SocketConnectorConfig) (adapters.Socket
 		return nil, err
 	}
 
+	err = config.EnhanceConn(conn)
+	if err != nil {
+		return nil, err
+	}
+
 	serializationType := readSerializationType(respHeaders)
 	return adapters.NewWebSocketAdapter(conn, serializationType, false, reader), nil
 }

client/connectors/webtransport.go

@@ -2,7 +2,9 @@ package connectors
 
 import (
 	"context"
+	"crypto/tls"
 	"errors"
+	"net"
 
 	"github.com/Doridian/wsvpn/shared/sockets/adapters"
 	"github.com/quic-go/quic-go"
@@ -19,13 +21,40 @@ func NewWebTransportConnector() *WebTransportConnector {
 	return &WebTransportConnector{}
 }
 
+type quicDialer struct {
+	transport *quic.Transport
+}
+
+func (d *quicDialer) Dial(ctx context.Context, addr string, tlsCfg *tls.Config, cfg *quic.Config) (quic.EarlyConnection, error) {
+	udpAddr, err := net.ResolveUDPAddr("udp", addr)
+	if err != nil {
+		return nil, err
+	}
+	return d.transport.DialEarly(ctx, udpAddr, tlsCfg, cfg)
+}
+
 func (c *WebTransportConnector) Dial(config SocketConnectorConfig) (adapters.SocketAdapter, error) {
 	serverURL := *config.GetServerURL()
 	serverURL.Scheme = "https"
 
+	udpConn, err := net.ListenUDP("udp", nil)
+	if err != nil {
+		return nil, err
+	}
+	err = config.EnhanceConn(udpConn)
+	if err != nil {
+		_ = udpConn.Close()
+		return nil, err
+	}
+	quicDialer := &quicDialer{
+		transport: &quic.Transport{Conn: udpConn},
+	}
+
 	var dialer webtransport.Dialer
 	if dialer.RoundTripper == nil {
-		dialer.RoundTripper = &http3.RoundTripper{}
+		dialer.RoundTripper = &http3.RoundTripper{
+			Dial: quicDialer.Dial,
+		}
 	}
 	dialer.TLSClientConfig = config.GetTLSConfig()
 

tests/bins.py

@@ -78,6 +78,7 @@ def __init__(self, proj: str) -> None:
             self.cfg["client"]["headers"] = {
                 "X-Test-Header": ["test-header-value"]
             }
+            self.cfg["firewall-mark"] = 1337
 
         self.proc_wait_cond = Condition()
         self.is_ready_or_done = False