Feature: mark on socket (#1705)

component/dialer/dialer.go

@@ -59,6 +59,9 @@ func ListenPacket(ctx context.Context, network, address string, options ...Optio
 	if cfg.addrReuse {
 		addrReuseToListenConfig(lc)
 	}
+	if cfg.routingMark != 0 {
+		bindMarkToListenConfig(cfg.routingMark, lc, network, address)
+	}
 
 	return lc.ListenPacket(ctx, network, address)
 }
@@ -82,6 +85,9 @@ func dialContext(ctx context.Context, network string, destination net.IP, port s
 			return nil, err
 		}
 	}
+	if opt.routingMark != 0 {
+		bindMarkToDialer(opt.routingMark, dialer, network, destination)
+	}
 
 	return dialer.DialContext(ctx, network, net.JoinHostPort(destination.String(), port))
 }

component/dialer/mark_linux.go

@@ -0,0 +1,44 @@
+//go:build linux
+// +build linux
+
+package dialer
+
+import (
+	"net"
+	"syscall"
+)
+
+func bindMarkToDialer(mark int, dialer *net.Dialer, _ string, _ net.IP) {
+	dialer.Control = bindMarkToControl(mark, dialer.Control)
+}
+
+func bindMarkToListenConfig(mark int, lc *net.ListenConfig, _, address string) {
+	lc.Control = bindMarkToControl(mark, lc.Control)
+}
+
+func bindMarkToControl(mark int, chain controlFn) controlFn {
+	return func(network, address string, c syscall.RawConn) (err error) {
+		defer func() {
+			if err == nil && chain != nil {
+				err = chain(network, address, c)
+			}
+		}()
+
+		ipStr, _, err := net.SplitHostPort(address)
+		if err == nil {
+			ip := net.ParseIP(ipStr)
+			if ip != nil && !ip.IsGlobalUnicast() {
+				return
+			}
+		}
+
+		return c.Control(func(fd uintptr) {
+			switch network {
+			case "tcp4", "udp4":
+				syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_MARK, mark)
+			case "tcp6", "udp6":
+				syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_MARK, mark)
+			}
+		})
+	}
+}

component/dialer/mark_nonlinux.go

@@ -0,0 +1,27 @@
+//go:build !linux
+// +build !linux
+
+package dialer
+
+import (
+	"net"
+	"sync"
+
+	"github.com/Dreamacro/clash/log"
+)
+
+var printMarkWarnOnce sync.Once
+
+func printMarkWarn() {
+	printMarkWarnOnce.Do(func() {
+		log.Warnln("Routing mark on socket is not supported on current platform")
+	})
+}
+
+func bindMarkToDialer(mark int, dialer *net.Dialer, _ string, _ net.IP) {
+	printMarkWarn()
+}
+
+func bindMarkToListenConfig(mark int, lc *net.ListenConfig, _, address string) {
+	printMarkWarn()
+}

component/dialer/options.go

@@ -10,6 +10,7 @@ var (
 type option struct {
 	interfaceName string
 	addrReuse     bool
+	routingMark   int
 }
 
 type Option func(opt *option)
@@ -25,3 +26,9 @@ func WithAddrReuse(reuse bool) Option {
 		opt.addrReuse = reuse
 	}
 }
+
+func WithRoutingMark(mark int) Option {
+	return func(opt *option) {
+		opt.routingMark = mark
+	}
+}