Enable splice for freedom outbound (downlink only)

- Add outbound name
- Add outbound conn in ctx
- Refactor splice: it can be turn on from all inbounds and outbounds
- Refactor splice: Add splice copy to vless inbound
- Fix http error test
- Add freedom splice toggle via env var
- Populate outbound obj in context
- Use CanSpliceCopy to mark a connection
- Turn off splice by default

proxy/vless/inbound/inbound.go

@@ -10,11 +10,9 @@ import (
 	"reflect"
 	"strconv"
 	"strings"
-	"syscall"
 	"time"
 	"unsafe"
 
-	"github.com/pires/go-proxyproto"
 	"github.com/xtls/xray-core/common"
 	"github.com/xtls/xray-core/common/buf"
 	"github.com/xtls/xray-core/common/errors"
@@ -30,7 +28,6 @@ import (
 	feature_inbound "github.com/xtls/xray-core/features/inbound"
 	"github.com/xtls/xray-core/features/policy"
 	"github.com/xtls/xray-core/features/routing"
-	"github.com/xtls/xray-core/features/stats"
 	"github.com/xtls/xray-core/proxy/vless"
 	"github.com/xtls/xray-core/proxy/vless/encoding"
 	"github.com/xtls/xray-core/transport/internet/reality"
@@ -182,8 +179,7 @@ func (h *Handler) Process(ctx context.Context, network net.Network, connection s
 	sid := session.ExportIDToError(ctx)
 
 	iConn := connection
-	statConn, ok := iConn.(*stat.CounterConnection)
-	if ok {
+	if statConn, ok := iConn.(*stat.CounterConnection); ok {
 		iConn = statConn.Connection
 	}
 
@@ -447,14 +443,12 @@ func (h *Handler) Process(ctx context.Context, network net.Network, connection s
 		// Flow: requestAddons.Flow,
 	}
 
-	var netConn net.Conn
-	var rawConn syscall.RawConn
 	var input *bytes.Reader
 	var rawInput *bytes.Buffer
-
 	switch requestAddons.Flow {
 	case vless.XRV:
 		if account.Flow == requestAddons.Flow {
+			inbound.SetCanSpliceCopy(2)
 			switch request.Command {
 			case protocol.RequestCommandUDP:
 				return newError(requestAddons.Flow + " doesn't support UDP").AtWarning()
@@ -467,23 +461,14 @@ func (h *Handler) Process(ctx context.Context, network net.Network, connection s
 					if tlsConn.ConnectionState().Version != gotls.VersionTLS13 {
 						return newError(`failed to use `+requestAddons.Flow+`, found outer tls version `, tlsConn.ConnectionState().Version).AtWarning()
 					}
-					netConn = tlsConn.NetConn()
 					t = reflect.TypeOf(tlsConn.Conn).Elem()
 					p = uintptr(unsafe.Pointer(tlsConn.Conn))
 				} else if realityConn, ok := iConn.(*reality.Conn); ok {
-					netConn = realityConn.NetConn()
 					t = reflect.TypeOf(realityConn.Conn).Elem()
 					p = uintptr(unsafe.Pointer(realityConn.Conn))
 				} else {
 					return newError("XTLS only supports TLS and REALITY directly for now.").AtWarning()
 				}
-				if pc, ok := netConn.(*proxyproto.Conn); ok {
-					netConn = pc.Raw()
-					// 8192 > 4096, there is no need to process pc's bufReader
-				}
-				if sc, ok := netConn.(syscall.Conn); ok {
-					rawConn, _ = sc.SyscallConn()
-				}
 				i, _ := t.FieldByName("input")
 				r, _ := t.FieldByName("rawInput")
 				input = (*bytes.Reader)(unsafe.Pointer(p + i.Offset))
@@ -493,6 +478,7 @@ func (h *Handler) Process(ctx context.Context, network net.Network, connection s
 			return newError(account.ID.String() + " is not able to use " + requestAddons.Flow).AtWarning()
 		}
 	case "":
+		inbound.SetCanSpliceCopy(3)
 		if account.Flow == vless.XRV && (request.Command == protocol.RequestCommandTCP || isMuxAndNotXUDP(request, first)) {
 			return newError(account.ID.String() + " is not able to use \"\". Note that the pure TLS proxy has certain TLS in TLS characters.").AtWarning()
 		}
@@ -540,13 +526,8 @@ func (h *Handler) Process(ctx context.Context, network net.Network, connection s
 		var err error
 
 		if requestAddons.Flow == vless.XRV {
-			var counter stats.Counter
-			if statConn != nil {
-				counter = statConn.ReadCounter
-			}
-			// TODO enable splice
-			ctx = session.ContextWithInbound(ctx, nil)
-			err = encoding.XtlsRead(clientReader, serverWriter, timer, netConn, rawConn, input, rawInput, counter, ctx, account.ID.Bytes(),
+			ctx1 := session.ContextWithInbound(ctx, nil) // TODO enable splice
+			err = encoding.XtlsRead(clientReader, serverWriter, timer, connection, input, rawInput, ctx1, account.ID.Bytes(),
 				&numberOfPacketToFilter, &enableXtls, &isTLS12orAbove, &isTLS, &cipher, &remainingServerHello)
 		} else {
 			// from clientReader.ReadMultiBuffer to serverWriter.WriteMultiBufer
@@ -592,11 +573,7 @@ func (h *Handler) Process(ctx context.Context, network net.Network, connection s
 
 		var err error
 		if requestAddons.Flow == vless.XRV {
-			var counter stats.Counter
-			if statConn != nil {
-				counter = statConn.WriteCounter
-			}
-			err = encoding.XtlsWrite(serverReader, clientWriter, timer, netConn, counter, ctx, &numberOfPacketToFilter,
+			err = encoding.XtlsWrite(serverReader, clientWriter, timer, connection, ctx, &numberOfPacketToFilter,
 				&enableXtls, &isTLS12orAbove, &isTLS, &cipher, &remainingServerHello)
 		} else {
 			// from serverReader.ReadMultiBuffer to clientWriter.WriteMultiBufer