Add TLS fragment support

common/tlsfragment/wait_darwin.go

@@ -0,0 +1,93 @@
+package tf
+
+import (
+	"context"
+	"net"
+	"time"
+
+	"github.com/sagernet/sing/common/control"
+
+	"golang.org/x/sys/unix"
+)
+
+/*
+const tcpMaxNotifyAck = 10
+
+type tcpNotifyAckID uint32
+
+	type tcpNotifyAckComplete struct {
+		NotifyPending       uint32
+		NotifyCompleteCount uint32
+		NotifyCompleteID    [tcpMaxNotifyAck]tcpNotifyAckID
+	}
+
+var sizeOfTCPNotifyAckComplete = int(unsafe.Sizeof(tcpNotifyAckComplete{}))
+
+	func getsockoptTCPNotifyAckComplete(fd, level, opt int) (*tcpNotifyAckComplete, error) {
+		var value tcpNotifyAckComplete
+		vallen := uint32(sizeOfTCPNotifyAckComplete)
+		err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
+		return &value, err
+	}
+
+//go:linkname getsockopt golang.org/x/sys/unix.getsockopt
+func getsockopt(s int, level int, name int, val unsafe.Pointer, vallen *uint32) error
+
+	func waitAck(ctx context.Context, conn *net.TCPConn, _ time.Duration) error {
+		const TCP_NOTIFY_ACKNOWLEDGEMENT = 0x212
+		return control.Conn(conn, func(fd uintptr) error {
+			err := unix.SetsockoptInt(int(fd), unix.IPPROTO_TCP, TCP_NOTIFY_ACKNOWLEDGEMENT, 1)
+			if err != nil {
+				if errors.Is(err, unix.EINVAL) {
+					return waitAckFallback(ctx, conn, 0)
+				}
+				return err
+			}
+			for {
+				select {
+				case <-ctx.Done():
+					return ctx.Err()
+				default:
+				}
+				var ackComplete *tcpNotifyAckComplete
+				ackComplete, err = getsockoptTCPNotifyAckComplete(int(fd), unix.IPPROTO_TCP, TCP_NOTIFY_ACKNOWLEDGEMENT)
+				if err != nil {
+					return err
+				}
+				if ackComplete.NotifyPending == 0 {
+					return nil
+				}
+				time.Sleep(10 * time.Millisecond)
+			}
+		})
+	}
+*/
+
+func writeAndWaitAck(ctx context.Context, conn *net.TCPConn, payload []byte, fallbackDelay time.Duration) error {
+	_, err := conn.Write(payload)
+	if err != nil {
+		return err
+	}
+	return control.Conn(conn, func(fd uintptr) error {
+		start := time.Now()
+		for {
+			select {
+			case <-ctx.Done():
+				return ctx.Err()
+			default:
+			}
+			unacked, err := unix.GetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_NWRITE)
+			if err != nil {
+				return err
+			}
+			if unacked == 0 {
+				if time.Since(start) <= 20*time.Millisecond {
+					// under transparent proxy
+					time.Sleep(fallbackDelay)
+				}
+				return nil
+			}
+			time.Sleep(10 * time.Millisecond)
+		}
+	})
+}