Add dial parallel for outbound dialer

common/dialer/resolve_conn.go

@@ -0,0 +1,83 @@
+package dialer
+
+import (
+	"context"
+	"net"
+
+	"github.com/sagernet/sing/common"
+	"github.com/sagernet/sing/common/buf"
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+
+	"github.com/sagernet/sing-box/adapter"
+	C "github.com/sagernet/sing-box/constant"
+)
+
+func NewResolvePacketConn(router adapter.Router, strategy C.DomainStrategy, conn net.PacketConn) N.NetPacketConn {
+	if udpConn, ok := conn.(*net.UDPConn); ok {
+		return &ResolveUDPConn{udpConn, router, strategy}
+	} else {
+		return &ResolvePacketConn{conn, router, strategy}
+	}
+}
+
+type ResolveUDPConn struct {
+	*net.UDPConn
+	router   adapter.Router
+	strategy C.DomainStrategy
+}
+
+func (w *ResolveUDPConn) ReadPacket(buffer *buf.Buffer) (M.Socksaddr, error) {
+	n, addr, err := w.ReadFromUDPAddrPort(buffer.FreeBytes())
+	if err != nil {
+		return M.Socksaddr{}, err
+	}
+	buffer.Truncate(n)
+	return M.SocksaddrFromNetIP(addr), nil
+}
+
+func (w *ResolveUDPConn) WritePacket(buffer *buf.Buffer, destination M.Socksaddr) error {
+	defer buffer.Release()
+	if destination.Family().IsFqdn() {
+		addresses, err := w.router.Lookup(context.Background(), destination.Fqdn, w.strategy)
+		if err != nil {
+			return err
+		}
+		return common.Error(w.UDPConn.WriteTo(buffer.Bytes(), M.SocksaddrFromAddrPort(addresses[0], destination.Port).UDPAddr()))
+	}
+	return common.Error(w.UDPConn.WriteToUDP(buffer.Bytes(), destination.UDPAddr()))
+}
+
+func (w *ResolveUDPConn) Upstream() any {
+	return w.UDPConn
+}
+
+type ResolvePacketConn struct {
+	net.PacketConn
+	router   adapter.Router
+	strategy C.DomainStrategy
+}
+
+func (w *ResolvePacketConn) ReadPacket(buffer *buf.Buffer) (M.Socksaddr, error) {
+	_, addr, err := buffer.ReadPacketFrom(w)
+	if err != nil {
+		return M.Socksaddr{}, err
+	}
+	return M.SocksaddrFromNet(addr), err
+}
+
+func (w *ResolvePacketConn) WritePacket(buffer *buf.Buffer, destination M.Socksaddr) error {
+	defer buffer.Release()
+	if destination.Family().IsFqdn() {
+		addresses, err := w.router.Lookup(context.Background(), destination.Fqdn, w.strategy)
+		if err != nil {
+			return err
+		}
+		return common.Error(w.WriteTo(buffer.Bytes(), M.SocksaddrFromAddrPort(addresses[0], destination.Port).UDPAddr()))
+	}
+	return common.Error(w.WriteTo(buffer.Bytes(), destination.UDPAddr()))
+}
+
+func (w *ResolvePacketConn) Upstream() any {
+	return w.PacketConn
+}