Add Syscall[Read/Write]Creator interface

Author: nekohasekai

common/bufio/copy.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"io"
 	"net"
-	"syscall"
 
 	"github.com/sagernet/sing/common"
 	"github.com/sagernet/sing/common/buf"
@@ -58,25 +57,11 @@ func CopyWithIncreateBuffer(destination io.Writer, source io.Reader, increaseBuf
 	return CopyWithCounters(destination, source, originSource, readCounters, writeCounters, increaseBufferAfter, batchSize)
 }
 
-type syscallReader interface {
-	io.Reader
-	syscall.Conn
-}
-
-type syscallWriter interface {
-	io.Writer
-	syscall.Conn
-}
-
 func CopyWithCounters(destination io.Writer, source io.Reader, originSource io.Reader, readCounters []N.CountFunc, writeCounters []N.CountFunc, increaseBufferAfter int64, batchSize int) (n int64, err error) {
-	srcSyscallConn, srcIsSyscall := N.CastReader[syscallReader](source)
-	dstSyscallConn, dstIsSyscall := N.CastWriter[syscallWriter](destination)
-	if srcIsSyscall && dstIsSyscall {
-		var handled bool
-		handled, n, err = copyDirect(srcSyscallConn, dstSyscallConn, readCounters, writeCounters)
-		if handled {
-			return
-		}
+	var handled bool
+	handled, n, err = copyDirect(source, destination, readCounters, writeCounters)
+	if handled {
+		return
 	}
 	return CopyExtended(originSource, NewExtendedWriter(destination), NewExtendedReader(source), readCounters, writeCounters, increaseBufferAfter, batchSize)
 }

common/bufio/copy_direct.go

@@ -3,19 +3,26 @@ package bufio
 import (
 	"errors"
 	"io"
-	"syscall"
 
 	"github.com/sagernet/sing/common/buf"
 	M "github.com/sagernet/sing/common/metadata"
 	N "github.com/sagernet/sing/common/network"
 )
 
-func copyDirect(source syscall.Conn, destination syscall.Conn, readCounters []N.CountFunc, writeCounters []N.CountFunc) (handed bool, n int64, err error) {
-	rawSource, err := source.SyscallConn()
+func copyDirect(source io.Reader, destination io.Writer, readCounters []N.CountFunc, writeCounters []N.CountFunc) (handed bool, n int64, err error) {
+	if !N.SyscallAvailableForRead(source) || !N.SyscallAvailableForWrite(destination) {
+		return
+	}
+	sourceConn := N.SyscallConnForRead(source)
+	destinationConn := N.SyscallConnForWrite(destination)
+	if sourceConn == nil || destinationConn == nil {
+		return
+	}
+	rawSource, err := sourceConn.SyscallConn()
 	if err != nil {
 		return
 	}
-	rawDestination, err := destination.SyscallConn()
+	rawDestination, err := destinationConn.SyscallConn()
 	if err != nil {
 		return
 	}

common/network/direct.go

@@ -1,6 +1,10 @@
 package network
 
 import (
+	"io"
+	"syscall"
+
+	"github.com/sagernet/sing/common"
 	"github.com/sagernet/sing/common/buf"
 	M "github.com/sagernet/sing/common/metadata"
 )
@@ -109,3 +113,87 @@ type VectorisedPacketReadWaiter interface {
 type VectorisedPacketReadWaitCreator interface {
 	CreateVectorisedPacketReadWaiter() (VectorisedPacketReadWaiter, bool)
 }
+
+type SyscallReadCreator interface {
+	SyscallConnForRead() syscall.Conn
+}
+
+func SyscallAvailableForRead(reader io.Reader) bool {
+	if _, ok := reader.(syscall.Conn); ok {
+		return true
+	}
+	if _, ok := reader.(SyscallReadCreator); ok {
+		return true
+	}
+	if u, ok := reader.(ReaderWithUpstream); !ok || !u.ReaderReplaceable() {
+		return false
+	}
+	if u, ok := reader.(WithUpstreamReader); ok {
+		return SyscallAvailableForRead(u.UpstreamReader().(io.Reader))
+	}
+	if u, ok := reader.(common.WithUpstream); ok {
+		return SyscallAvailableForRead(u.Upstream().(io.Reader))
+	}
+	return false
+}
+
+func SyscallConnForRead(reader io.Reader) syscall.Conn {
+	if c, ok := reader.(syscall.Conn); ok {
+		return c
+	}
+	if c, ok := reader.(SyscallReadCreator); ok {
+		return c.SyscallConnForRead()
+	}
+	if u, ok := reader.(ReaderWithUpstream); !ok || !u.ReaderReplaceable() {
+		return nil
+	}
+	if u, ok := reader.(WithUpstreamReader); ok {
+		return SyscallConnForRead(u.UpstreamReader().(io.Reader))
+	}
+	if u, ok := reader.(common.WithUpstream); ok {
+		return SyscallConnForRead(u.Upstream().(io.Reader))
+	}
+	return nil
+}
+
+type SyscallWriteCreator interface {
+	SyscallConnForWrite() syscall.Conn
+}
+
+func SyscallAvailableForWrite(writer io.Writer) bool {
+	if _, ok := writer.(syscall.Conn); ok {
+		return true
+	}
+	if _, ok := writer.(SyscallWriteCreator); ok {
+		return true
+	}
+	if u, ok := writer.(WriterWithUpstream); !ok || !u.WriterReplaceable() {
+		return false
+	}
+	if u, ok := writer.(WithUpstreamWriter); ok {
+		return SyscallAvailableForWrite(u.UpstreamWriter().(io.Writer))
+	}
+	if u, ok := writer.(common.WithUpstream); ok {
+		return SyscallAvailableForWrite(u.Upstream().(io.Writer))
+	}
+	return false
+}
+
+func SyscallConnForWrite(writer io.Writer) syscall.Conn {
+	if c, ok := writer.(syscall.Conn); ok {
+		return c
+	}
+	if c, ok := writer.(SyscallWriteCreator); ok {
+		return c.SyscallConnForWrite()
+	}
+	if u, ok := writer.(WriterWithUpstream); !ok || !u.WriterReplaceable() {
+		return nil
+	}
+	if u, ok := writer.(WithUpstreamWriter); ok {
+		return SyscallConnForWrite(u.UpstreamWriter().(io.Writer))
+	}
+	if u, ok := writer.(common.WithUpstream); ok {
+		return SyscallConnForWrite(u.Upstream().(io.Writer))
+	}
+	return nil
+}