Add redir tproxy and dns inbound

inbound/dns.go

@@ -5,16 +5,59 @@ import (
 	"encoding/binary"
 	"io"
 	"net"
+	"net/netip"
 
 	"github.com/sagernet/sing-box/adapter"
+	C "github.com/sagernet/sing-box/constant"
 	"github.com/sagernet/sing-box/log"
+	"github.com/sagernet/sing-box/option"
 	"github.com/sagernet/sing/common"
 	"github.com/sagernet/sing/common/buf"
 	N "github.com/sagernet/sing/common/network"
+	"github.com/sagernet/sing/common/udpnat"
 
 	"golang.org/x/net/dns/dnsmessage"
 )
 
+type DNS struct {
+	myInboundAdapter
+	udpNat *udpnat.Service[netip.AddrPort]
+}
+
+func NewDNS(ctx context.Context, router adapter.Router, logger log.ContextLogger, tag string, options option.DNSInboundOptions) *DNS {
+	dns := &DNS{
+		myInboundAdapter: myInboundAdapter{
+			protocol:      C.TypeTProxy,
+			network:       options.Network.Build(),
+			ctx:           ctx,
+			router:        router,
+			logger:        logger,
+			tag:           tag,
+			listenOptions: options.ListenOptions,
+		},
+	}
+	dns.connHandler = dns
+	dns.packetHandler = dns
+	dns.udpNat = udpnat.New[netip.AddrPort](10, adapter.NewUpstreamContextHandler(nil, dns.newPacketConnection, dns))
+	dns.packetUpstream = dns.udpNat
+	return dns
+}
+
+func (d *DNS) NewConnection(ctx context.Context, conn net.Conn, metadata adapter.InboundContext) error {
+	return NewDNSConnection(ctx, d.router, d.logger, conn, metadata)
+}
+
+func (d *DNS) NewPacket(ctx context.Context, conn N.PacketConn, buffer *buf.Buffer, metadata adapter.InboundContext) error {
+	d.udpNat.NewContextPacket(ctx, metadata.Source.AddrPort(), buffer, adapter.UpstreamMetadata(metadata), func(natConn N.PacketConn) (context.Context, N.PacketWriter) {
+		return adapter.WithContext(log.ContextWithNewID(ctx), &metadata), natConn
+	})
+	return nil
+}
+
+func (d *DNS) newPacketConnection(ctx context.Context, conn N.PacketConn, metadata adapter.InboundContext) error {
+	return NewDNSPacketConnection(ctx, d.router, d.logger, conn, metadata)
+}
+
 func NewDNSConnection(ctx context.Context, router adapter.Router, logger log.ContextLogger, conn net.Conn, metadata adapter.InboundContext) error {
 	ctx = adapter.WithContext(ctx, &metadata)
 	_buffer := buf.StackNewSize(1024)