Fix dial parallel in direct outbound

outbound/direct.go

@@ -4,12 +4,14 @@ import (
 	"context"
 	"net"
 	"net/netip"
+	"time"
 
 	"github.com/sagernet/sing-box/adapter"
 	"github.com/sagernet/sing-box/common/dialer"
 	C "github.com/sagernet/sing-box/constant"
 	"github.com/sagernet/sing-box/log"
 	"github.com/sagernet/sing-box/option"
+	"github.com/sagernet/sing-dns"
 	E "github.com/sagernet/sing/common/exceptions"
 	M "github.com/sagernet/sing/common/metadata"
 	N "github.com/sagernet/sing/common/network"
@@ -17,11 +19,16 @@ import (
 	"github.com/pires/go-proxyproto"
 )
 
-var _ adapter.Outbound = (*Direct)(nil)
+var (
+	_ adapter.Outbound = (*Direct)(nil)
+	_ N.ParallelDialer = (*Direct)(nil)
+)
 
 type Direct struct {
 	myOutboundAdapter
 	dialer              N.Dialer
+	domainStrategy      dns.DomainStrategy
+	fallbackDelay       time.Duration
 	overrideOption      int
 	overrideDestination M.Socksaddr
 	proxyProto          uint8
@@ -36,8 +43,10 @@ func NewDirect(router adapter.Router, logger log.ContextLogger, tag string, opti
 			logger:   logger,
 			tag:      tag,
 		},
-		dialer:     dialer.NewOutbound(router, options.OutboundDialerOptions),
-		proxyProto: options.ProxyProtocol,
+		domainStrategy: dns.DomainStrategy(options.DomainStrategy),
+		fallbackDelay:  time.Duration(options.FallbackDelay),
+		dialer:         dialer.NewOutbound(router, options.OutboundDialerOptions),
+		proxyProto:     options.ProxyProtocol,
 	}
 	if options.ProxyProtocol > 2 {
 		return nil, E.New("invalid proxy protocol option: ", options.ProxyProtocol)
@@ -99,6 +108,53 @@ func (h *Direct) DialContext(ctx context.Context, network string, destination M.
 	return conn, nil
 }
 
+func (h *Direct) DialParallel(ctx context.Context, network string, destination M.Socksaddr, destinationAddresses []netip.Addr) (net.Conn, error) {
+	ctx, metadata := adapter.AppendContext(ctx)
+	originDestination := metadata.Destination
+	metadata.Outbound = h.tag
+	metadata.Destination = destination
+	switch h.overrideOption {
+	case 1, 2:
+		// override address
+		return h.DialContext(ctx, network, destination)
+	case 3:
+		destination.Port = h.overrideDestination.Port
+	}
+	network = N.NetworkName(network)
+	switch network {
+	case N.NetworkTCP:
+		h.logger.InfoContext(ctx, "outbound connection to ", destination)
+	case N.NetworkUDP:
+		h.logger.InfoContext(ctx, "outbound packet connection to ", destination)
+	}
+	var domainStrategy dns.DomainStrategy
+	if h.domainStrategy != dns.DomainStrategyAsIS {
+		domainStrategy = h.domainStrategy
+	} else {
+		domainStrategy = metadata.DomainStrategy
+	}
+	conn, err := N.DialParallel(ctx, h.dialer, network, destination, destinationAddresses, domainStrategy == dns.DomainStrategyPreferIPv6, h.fallbackDelay)
+	if err != nil {
+		return nil, err
+	}
+	if h.proxyProto > 0 {
+		source := metadata.Source
+		if !source.IsValid() {
+			source = M.SocksaddrFromNet(conn.LocalAddr())
+		}
+		if originDestination.Addr.Is6() {
+			source = M.SocksaddrFrom(netip.AddrFrom16(source.Addr.As16()), source.Port)
+		}
+		header := proxyproto.HeaderProxyFromAddrs(h.proxyProto, source.TCPAddr(), originDestination.TCPAddr())
+		_, err = header.WriteTo(conn)
+		if err != nil {
+			conn.Close()
+			return nil, E.Cause(err, "write proxy protocol header")
+		}
+	}
+	return conn, nil
+}
+
 func (h *Direct) ListenPacket(ctx context.Context, destination M.Socksaddr) (net.PacketConn, error) {
 	ctx, metadata := adapter.AppendContext(ctx)
 	metadata.Outbound = h.tag