Add E.Cause1

.github/workflows/lint.yml

@@ -26,7 +26,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v5
         with:
-          go-version: ^1.22
+          go-version: ^1.23
       - name: Cache go module
         uses: actions/cache@v4
         with:

.github/workflows/test.yml

@@ -26,7 +26,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v5
         with:
-          go-version: ^1.22
+          go-version: ^1.23
       - name: Build
         run: |
           make test
@@ -62,6 +62,22 @@ jobs:
       - name: Build
         run: |
           make test
+  build_go122:
+    name: Linux (Go 1.22)
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: ~1.22
+        continue-on-error: true
+      - name: Build
+        run: |
+          make test
   build_windows:
     name: Windows
     runs-on: windows-latest
@@ -73,7 +89,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v5
         with:
-          go-version: ^1.22
+          go-version: ^1.23
         continue-on-error: true
       - name: Build
         run: |
@@ -89,7 +105,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v5
         with:
-          go-version: ^1.22
+          go-version: ^1.23
         continue-on-error: true
       - name: Build
         run: |

.golangci.yml

@@ -5,6 +5,8 @@ linters:
     - govet
     - gci
     - staticcheck
+    - paralleltest
+    - ineffassign
 
 linters-settings:
   gci:
@@ -13,3 +15,10 @@ linters-settings:
       - standard
       - prefix(github.com/sagernet/)
       - default
+  staticcheck:
+    checks:
+      - all
+      - -SA1003
+
+run:
+  go: "1.23"

Makefile

@@ -8,14 +8,14 @@ fmt_install:
 	go install -v github.com/daixiang0/gci@latest
 
 lint:
-	GOOS=linux golangci-lint run ./...
-	GOOS=android golangci-lint run ./...
-	GOOS=windows golangci-lint run ./...
-	GOOS=darwin golangci-lint run ./...
-	GOOS=freebsd golangci-lint run ./...
+	GOOS=linux golangci-lint run
+	GOOS=android golangci-lint run
+	GOOS=windows golangci-lint run
+	GOOS=darwin golangci-lint run
+	GOOS=freebsd golangci-lint run
 
 lint_install:
 	go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest
 
 test:
-	go test $(shell go list ./... | grep -v /internal/)
+	go test ./...

common/baderror/baderror.go

@@ -2,11 +2,10 @@ package baderror
 
 import (
 	"context"
+	"errors"
 	"io"
 	"net"
 	"strings"
-
-	E "github.com/sagernet/sing/common/exceptions"
 )
 
 func Contains(err error, msgList ...string) bool {
@@ -22,8 +21,7 @@ func WrapH2(err error) error {
 	if err == nil {
 		return nil
 	}
-	err = E.Unwrap(err)
-	if err == io.ErrUnexpectedEOF {
+	if errors.Is(err, io.ErrUnexpectedEOF) {
 		return io.EOF
 	}
 	if Contains(err, "client disconnected", "body closed by handler", "response body closed", "; CANCEL") {

common/bufio/addr_conn.go

@@ -9,19 +9,20 @@ import (
 
 type AddrConn struct {
 	net.Conn
-	M.Metadata
+	Source      M.Socksaddr
+	Destination M.Socksaddr
 }
 
 func (c *AddrConn) LocalAddr() net.Addr {
-	if c.Metadata.Destination.IsValid() {
-		return c.Metadata.Destination.TCPAddr()
+	if c.Destination.IsValid() {
+		return c.Destination.TCPAddr()
 	}
 	return c.Conn.LocalAddr()
 }
 
 func (c *AddrConn) RemoteAddr() net.Addr {
-	if c.Metadata.Source.IsValid() {
-		return c.Metadata.Source.TCPAddr()
+	if c.Source.IsValid() {
+		return c.Source.TCPAddr()
 	}
 	return c.Conn.RemoteAddr()
 }

common/bufio/cache.go

@@ -3,7 +3,6 @@ package bufio
 import (
 	"io"
 	"net"
-	"time"
 
 	"github.com/sagernet/sing/common/buf"
 	M "github.com/sagernet/sing/common/metadata"
@@ -60,13 +59,6 @@ func (c *CachedConn) WriteTo(w io.Writer) (n int64, err error) {
 	return
 }
 
-func (c *CachedConn) SetReadDeadline(t time.Time) error {
-	if c.buffer != nil && !c.buffer.IsEmpty() {
-		return nil
-	}
-	return c.Conn.SetReadDeadline(t)
-}
-
 func (c *CachedConn) ReadFrom(r io.Reader) (n int64, err error) {
 	return Copy(c.Conn, r)
 }
@@ -192,10 +184,12 @@ func (c *CachedPacketConn) ReadCachedPacket() *N.PacketBuffer {
 	if buffer != nil {
 		buffer.DecRef()
 	}
-	return &N.PacketBuffer{
+	packet := N.NewPacketBuffer()
+	*packet = N.PacketBuffer{
 		Buffer:      buffer,
 		Destination: c.destination,
 	}
+	return packet
 }
 
 func (c *CachedPacketConn) Upstream() any {

common/bufio/conn.go

@@ -35,14 +35,7 @@ func (w *ExtendedUDPConn) ReadPacket(buffer *buf.Buffer) (M.Socksaddr, error) {
 
 func (w *ExtendedUDPConn) WritePacket(buffer *buf.Buffer, destination M.Socksaddr) error {
 	defer buffer.Release()
-	if destination.IsFqdn() {
-		udpAddr, err := net.ResolveUDPAddr("udp", destination.String())
-		if err != nil {
-			return err
-		}
-		return common.Error(w.UDPConn.WriteTo(buffer.Bytes(), udpAddr))
-	}
-	return common.Error(w.UDPConn.WriteToUDP(buffer.Bytes(), destination.UDPAddr()))
+	return common.Error(w.UDPConn.WriteToUDPAddrPort(buffer.Bytes(), destination.AddrPort()))
 }
 
 func (w *ExtendedUDPConn) Upstream() any {

common/bufio/copy.go

@@ -29,28 +29,36 @@ func Copy(destination io.Writer, source io.Reader) (n int64, err error) {
 		if cachedSrc, isCached := source.(N.CachedReader); isCached {
 			cachedBuffer := cachedSrc.ReadCached()
 			if cachedBuffer != nil {
-				if !cachedBuffer.IsEmpty() {
-					_, err = destination.Write(cachedBuffer.Bytes())
-					if err != nil {
-						cachedBuffer.Release()
-						return
-					}
-				}
+				dataLen := cachedBuffer.Len()
+				_, err = destination.Write(cachedBuffer.Bytes())
 				cachedBuffer.Release()
+				if err != nil {
+					return
+				}
+				for _, counter := range readCounters {
+					counter(int64(dataLen))
+				}
+				for _, counter := range writeCounters {
+					counter(int64(dataLen))
+				}
 				continue
 			}
 		}
-		srcSyscallConn, srcIsSyscall := source.(syscall.Conn)
-		dstSyscallConn, dstIsSyscall := destination.(syscall.Conn)
-		if srcIsSyscall && dstIsSyscall {
-			var handled bool
-			handled, n, err = copyDirect(srcSyscallConn, dstSyscallConn, readCounters, writeCounters)
-			if handled {
-				return
-			}
-		}
 		break
 	}
+	return CopyWithCounters(destination, source, originSource, readCounters, writeCounters)
+}
+
+func CopyWithCounters(destination io.Writer, source io.Reader, originSource io.Reader, readCounters []N.CountFunc, writeCounters []N.CountFunc) (n int64, err error) {
+	srcSyscallConn, srcIsSyscall := source.(syscall.Conn)
+	dstSyscallConn, dstIsSyscall := destination.(syscall.Conn)
+	if srcIsSyscall && dstIsSyscall {
+		var handled bool
+		handled, n, err = copyDirect(srcSyscallConn, dstSyscallConn, readCounters, writeCounters)
+		if handled {
+			return
+		}
+	}
 	return CopyExtended(originSource, NewExtendedWriter(destination), NewExtendedReader(source), readCounters, writeCounters)
 }
 
@@ -75,6 +83,7 @@ func CopyExtended(originSource io.Reader, destination N.ExtendedWriter, source N
 	return CopyExtendedWithPool(originSource, destination, source, readCounters, writeCounters)
 }
 
+// Deprecated: not used
 func CopyExtendedBuffer(originSource io.Writer, destination N.ExtendedWriter, source N.ExtendedReader, buffer *buf.Buffer, readCounters []N.CountFunc, writeCounters []N.CountFunc) (n int64, err error) {
 	buffer.IncRef()
 	defer buffer.DecRef()
@@ -113,19 +122,10 @@ func CopyExtendedBuffer(originSource io.Writer, destination N.ExtendedWriter, so
 }
 
 func CopyExtendedWithPool(originSource io.Reader, destination N.ExtendedWriter, source N.ExtendedReader, readCounters []N.CountFunc, writeCounters []N.CountFunc) (n int64, err error) {
-	frontHeadroom := N.CalculateFrontHeadroom(destination)
-	rearHeadroom := N.CalculateRearHeadroom(destination)
-	bufferSize := N.CalculateMTU(source, destination)
-	if bufferSize > 0 {
-		bufferSize += frontHeadroom + rearHeadroom
-	} else {
-		bufferSize = buf.BufferSize
-	}
+	options := N.NewReadWaitOptions(source, destination)
 	var notFirstTime bool
 	for {
-		buffer := buf.NewSize(bufferSize)
-		buffer.Resize(frontHeadroom, 0)
-		buffer.Reserve(rearHeadroom)
+		buffer := options.NewBuffer()
 		err = source.ReadBuffer(buffer)
 		if err != nil {
 			buffer.Release()
@@ -136,7 +136,7 @@ func CopyExtendedWithPool(originSource io.Reader, destination N.ExtendedWriter,
 			return
 		}
 		dataLen := buffer.Len()
-		buffer.OverCap(rearHeadroom)
+		options.PostReturn(buffer)
 		err = destination.WriteBuffer(buffer)
 		if err != nil {
 			buffer.Leak()
@@ -157,10 +157,6 @@ func CopyExtendedWithPool(originSource io.Reader, destination N.ExtendedWriter,
 }
 
 func CopyConn(ctx context.Context, source net.Conn, destination net.Conn) error {
-	return CopyConnContextList([]context.Context{ctx}, source, destination)
-}
-
-func CopyConnContextList(contextList []context.Context, source net.Conn, destination net.Conn) error {
 	var group task.Group
 	if _, dstDuplex := common.Cast[N.WriteCloser](destination); dstDuplex {
 		group.Append("upload", func(ctx context.Context) error {
@@ -197,7 +193,7 @@ func CopyConnContextList(contextList []context.Context, source net.Conn, destina
 	group.Cleanup(func() {
 		common.Close(source, destination)
 	})
-	return group.RunContextList(contextList)
+	return group.Run(ctx)
 }
 
 func CopyPacket(destinationConn N.PacketWriter, source N.PacketReader) (n int64, err error) {
@@ -217,24 +213,24 @@ func CopyPacket(destinationConn N.PacketWriter, source N.PacketReader) (n int64,
 		break
 	}
 	if cachedPackets != nil {
-		n, err = WritePacketWithPool(originSource, destinationConn, cachedPackets)
+		n, err = WritePacketWithPool(originSource, destinationConn, cachedPackets, readCounters, writeCounters)
 		if err != nil {
 			return
 		}
 	}
-	frontHeadroom := N.CalculateFrontHeadroom(destinationConn)
-	rearHeadroom := N.CalculateRearHeadroom(destinationConn)
+	copeN, err := CopyPacketWithCounters(destinationConn, source, originSource, readCounters, writeCounters)
+	n += copeN
+	return
+}
+
+func CopyPacketWithCounters(destinationConn N.PacketWriter, source N.PacketReader, originSource N.PacketReader, readCounters []N.CountFunc, writeCounters []N.CountFunc) (n int64, err error) {
 	var (
 		handled bool
 		copeN   int64
 	)
 	readWaiter, isReadWaiter := CreatePacketReadWaiter(source)
 	if isReadWaiter {
-		needCopy := readWaiter.InitializeReadWaiter(N.ReadWaitOptions{
-			FrontHeadroom: frontHeadroom,
-			RearHeadroom:  rearHeadroom,
-			MTU:           N.CalculateMTU(source, destinationConn),
-		})
+		needCopy := readWaiter.InitializeReadWaiter(N.NewReadWaitOptions(source, destinationConn))
 		if !needCopy || common.LowMemory {
 			handled, copeN, err = copyPacketWaitWithPool(originSource, destinationConn, readWaiter, readCounters, writeCounters, n > 0)
 			if handled {
@@ -248,28 +244,19 @@ func CopyPacket(destinationConn N.PacketWriter, source N.PacketReader) (n int64,
 	return
 }
 
-func CopyPacketWithPool(originSource N.PacketReader, destinationConn N.PacketWriter, source N.PacketReader, readCounters []N.CountFunc, writeCounters []N.CountFunc, notFirstTime bool) (n int64, err error) {
-	frontHeadroom := N.CalculateFrontHeadroom(destinationConn)
-	rearHeadroom := N.CalculateRearHeadroom(destinationConn)
-	bufferSize := N.CalculateMTU(source, destinationConn)
-	if bufferSize > 0 {
-		bufferSize += frontHeadroom + rearHeadroom
-	} else {
-		bufferSize = buf.UDPBufferSize
-	}
-	var destination M.Socksaddr
+func CopyPacketWithPool(originSource N.PacketReader, destination N.PacketWriter, source N.PacketReader, readCounters []N.CountFunc, writeCounters []N.CountFunc, notFirstTime bool) (n int64, err error) {
+	options := N.NewReadWaitOptions(source, destination)
+	var destinationAddress M.Socksaddr
 	for {
-		buffer := buf.NewSize(bufferSize)
-		buffer.Resize(frontHeadroom, 0)
-		buffer.Reserve(rearHeadroom)
-		destination, err = source.ReadPacket(buffer)
+		buffer := options.NewPacketBuffer()
+		destinationAddress, err = source.ReadPacket(buffer)
 		if err != nil {
 			buffer.Release()
 			return
 		}
 		dataLen := buffer.Len()
-		buffer.OverCap(rearHeadroom)
-		err = destinationConn.WritePacket(buffer, destination)
+		options.PostReturn(buffer)
+		err = destination.WritePacket(buffer, destinationAddress)
 		if err != nil {
 			buffer.Leak()
 			if !notFirstTime {
@@ -277,34 +264,25 @@ func CopyPacketWithPool(originSource N.PacketReader, destinationConn N.PacketWri
 			}
 			return
 		}
-		n += int64(dataLen)
 		for _, counter := range readCounters {
 			counter(int64(dataLen))
 		}
 		for _, counter := range writeCounters {
 			counter(int64(dataLen))
 		}
+		n += int64(dataLen)
 		notFirstTime = true
 	}
 }
 
-func WritePacketWithPool(originSource N.PacketReader, destinationConn N.PacketWriter, packetBuffers []*N.PacketBuffer) (n int64, err error) {
-	frontHeadroom := N.CalculateFrontHeadroom(destinationConn)
-	rearHeadroom := N.CalculateRearHeadroom(destinationConn)
+func WritePacketWithPool(originSource N.PacketReader, destination N.PacketWriter, packetBuffers []*N.PacketBuffer, readCounters []N.CountFunc, writeCounters []N.CountFunc) (n int64, err error) {
+	options := N.NewReadWaitOptions(nil, destination)
 	var notFirstTime bool
 	for _, packetBuffer := range packetBuffers {
-		buffer := buf.NewPacket()
-		buffer.Resize(frontHeadroom, 0)
-		buffer.Reserve(rearHeadroom)
-		_, err = buffer.Write(packetBuffer.Buffer.Bytes())
-		packetBuffer.Buffer.Release()
-		if err != nil {
-			buffer.Release()
-			continue
-		}
+		buffer := options.Copy(packetBuffer.Buffer)
 		dataLen := buffer.Len()
-		buffer.OverCap(rearHeadroom)
-		err = destinationConn.WritePacket(buffer, packetBuffer.Destination)
+		err = destination.WritePacket(buffer, packetBuffer.Destination)
+		N.PutPacketBuffer(packetBuffer)
 		if err != nil {
 			buffer.Leak()
 			if !notFirstTime {
@@ -312,16 +290,19 @@ func WritePacketWithPool(originSource N.PacketReader, destinationConn N.PacketWr
 			}
 			return
 		}
+		for _, counter := range readCounters {
+			counter(int64(dataLen))
+		}
+		for _, counter := range writeCounters {
+			counter(int64(dataLen))
+		}
 		n += int64(dataLen)
+		notFirstTime = true
 	}
 	return
 }
 
 func CopyPacketConn(ctx context.Context, source N.PacketConn, destination N.PacketConn) error {
-	return CopyPacketConnContextList([]context.Context{ctx}, source, destination)
-}
-
-func CopyPacketConnContextList(contextList []context.Context, source N.PacketConn, destination N.PacketConn) error {
 	var group task.Group
 	group.Append("upload", func(ctx context.Context) error {
 		return common.Error(CopyPacket(destination, source))
@@ -333,5 +314,5 @@ func CopyPacketConnContextList(contextList []context.Context, source N.PacketCon
 		common.Close(source, destination)
 	})
 	group.FastFail()
-	return group.RunContextList(contextList)
+	return group.Run(ctx)
 }

common/bufio/copy_direct_windows.go

@@ -5,7 +5,6 @@ import (
 	"net/netip"
 	"os"
 	"syscall"
-	"unsafe"
 
 	"github.com/sagernet/sing/common/buf"
 	E "github.com/sagernet/sing/common/exceptions"
@@ -15,49 +14,6 @@ import (
 	"golang.org/x/sys/windows"
 )
 
-var modws2_32 = windows.NewLazySystemDLL("ws2_32.dll")
-
-var procrecv = modws2_32.NewProc("recv")
-
-// Do the interface allocations only once for common
-// Errno values.
-const (
-	errnoERROR_IO_PENDING = 997
-)
-
-var (
-	errERROR_IO_PENDING error = syscall.Errno(errnoERROR_IO_PENDING)
-	errERROR_EINVAL     error = syscall.EINVAL
-)
-
-// errnoErr returns common boxed Errno values, to prevent
-// allocations at runtime.
-func errnoErr(e syscall.Errno) error {
-	switch e {
-	case 0:
-		return errERROR_EINVAL
-	case errnoERROR_IO_PENDING:
-		return errERROR_IO_PENDING
-	}
-	// TODO: add more here, after collecting data on the common
-	// error values see on Windows. (perhaps when running
-	// all.bat?)
-	return e
-}
-
-func recv(s windows.Handle, buf []byte, flags int32) (n int32, err error) {
-	var _p0 *byte
-	if len(buf) > 0 {
-		_p0 = &buf[0]
-	}
-	r0, _, e1 := syscall.SyscallN(procrecv.Addr(), uintptr(s), uintptr(unsafe.Pointer(_p0)), uintptr(len(buf)), uintptr(flags))
-	n = int32(r0)
-	if n == -1 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
 var _ N.ReadWaiter = (*syscallReadWaiter)(nil)
 
 type syscallReadWaiter struct {
@@ -164,16 +120,16 @@ func (w *syscallPacketReadWaiter) InitializeReadWaiter(options N.ReadWaitOptions
 		var readN int
 		var from windows.Sockaddr
 		readN, from, w.readErr = windows.Recvfrom(windows.Handle(fd), buffer.FreeBytes(), 0)
+		//goland:noinspection GoDirectComparisonOfErrors
+		if w.readErr != nil {
+			buffer.Release()
+			return w.readErr != windows.WSAEWOULDBLOCK
+		}
 		if readN > 0 {
 			buffer.Truncate(readN)
-			w.options.PostReturn(buffer)
-			w.buffer = buffer
-		} else {
-			buffer.Release()
-		}
-		if w.readErr == windows.WSAEWOULDBLOCK {
-			return false
 		}
+		w.options.PostReturn(buffer)
+		w.buffer = buffer
 		if from != nil {
 			switch fromAddr := from.(type) {
 			case *windows.SockaddrInet4:

common/bufio/io.go

@@ -25,6 +25,45 @@ func ReadPacket(reader N.PacketReader, buffer *buf.Buffer) (n int, addr net.Addr
 	return
 }
 
+func ReadBufferSize(reader io.Reader, bufferSize int) (buffer *buf.Buffer, err error) {
+	readWaiter, isReadWaiter := CreateReadWaiter(reader)
+	if isReadWaiter {
+		readWaiter.InitializeReadWaiter(N.ReadWaitOptions{
+			MTU: bufferSize,
+		})
+		return readWaiter.WaitReadBuffer()
+	}
+	buffer = buf.NewSize(bufferSize)
+	if extendedReader, isExtendedReader := reader.(N.ExtendedReader); isExtendedReader {
+		err = extendedReader.ReadBuffer(buffer)
+	} else {
+		_, err = buffer.ReadOnceFrom(reader)
+	}
+	if err != nil {
+		buffer.Release()
+		buffer = nil
+	}
+	return
+}
+
+func ReadPacketSize(reader N.PacketReader, packetSize int) (buffer *buf.Buffer, destination M.Socksaddr, err error) {
+	readWaiter, isReadWaiter := CreatePacketReadWaiter(reader)
+	if isReadWaiter {
+		readWaiter.InitializeReadWaiter(N.ReadWaitOptions{
+			MTU: packetSize,
+		})
+		buffer, destination, err = readWaiter.WaitReadPacket()
+		return
+	}
+	buffer = buf.NewSize(packetSize)
+	destination, err = reader.ReadPacket(buffer)
+	if err != nil {
+		buffer.Release()
+		buffer = nil
+	}
+	return
+}
+
 func Write(writer io.Writer, data []byte) (n int, err error) {
 	if extendedWriter, isExtended := writer.(N.ExtendedWriter); isExtended {
 		return WriteBuffer(extendedWriter, buf.As(data))

common/bufio/nat.go

@@ -30,6 +30,14 @@ func NewNATPacketConn(conn N.NetPacketConn, origin M.Socksaddr, destination M.So
 	}
 }
 
+func NewDestinationNATPacketConn(conn N.NetPacketConn, origin M.Socksaddr, destination M.Socksaddr) NATPacketConn {
+	return &destinationNATPacketConn{
+		NetPacketConn: conn,
+		origin:        origin,
+		destination:   destination,
+	}
+}
+
 type unidirectionalNATPacketConn struct {
 	N.NetPacketConn
 	origin      M.Socksaddr
@@ -144,6 +152,60 @@ func (c *bidirectionalNATPacketConn) RemoteAddr() net.Addr {
 	return c.destination.UDPAddr()
 }
 
+type destinationNATPacketConn struct {
+	N.NetPacketConn
+	origin      M.Socksaddr
+	destination M.Socksaddr
+}
+
+func (c *destinationNATPacketConn) ReadFrom(p []byte) (n int, addr net.Addr, err error) {
+	n, addr, err = c.NetPacketConn.ReadFrom(p)
+	if err != nil {
+		return
+	}
+	if M.SocksaddrFromNet(addr) == c.origin {
+		addr = c.destination.UDPAddr()
+	}
+	return
+}
+
+func (c *destinationNATPacketConn) WriteTo(p []byte, addr net.Addr) (n int, err error) {
+	if M.SocksaddrFromNet(addr) == c.destination {
+		addr = c.origin.UDPAddr()
+	}
+	return c.NetPacketConn.WriteTo(p, addr)
+}
+
+func (c *destinationNATPacketConn) ReadPacket(buffer *buf.Buffer) (destination M.Socksaddr, err error) {
+	destination, err = c.NetPacketConn.ReadPacket(buffer)
+	if err != nil {
+		return
+	}
+	if destination == c.origin {
+		destination = c.destination
+	}
+	return
+}
+
+func (c *destinationNATPacketConn) WritePacket(buffer *buf.Buffer, destination M.Socksaddr) error {
+	if destination == c.destination {
+		destination = c.origin
+	}
+	return c.NetPacketConn.WritePacket(buffer, destination)
+}
+
+func (c *destinationNATPacketConn) UpdateDestination(destinationAddress netip.Addr) {
+	c.destination = M.SocksaddrFrom(destinationAddress, c.destination.Port)
+}
+
+func (c *destinationNATPacketConn) Upstream() any {
+	return c.NetPacketConn
+}
+
+func (c *destinationNATPacketConn) RemoteAddr() net.Addr {
+	return c.destination.UDPAddr()
+}
+
 func socksaddrWithoutPort(destination M.Socksaddr) M.Socksaddr {
 	destination.Port = 0
 	return destination

common/bufio/net_test.go

@@ -36,7 +36,7 @@ func TCPPipe(t *testing.T) (net.Conn, net.Conn) {
 		clientConn, clientErr = net.Dial("tcp", listener.Addr().String())
 		return clientErr
 	})
-	err = group.Run()
+	err = group.Run(context.Background())
 	require.NoError(t, err)
 	listener.Close()
 	t.Cleanup(func() {

common/bufio/syscall_windows.go

@@ -0,0 +1,5 @@
+package bufio
+
+//go:generate go run golang.org/x/sys/windows/mkwinsyscall -output zsyscall_windows.go syscall_windows.go
+
+//sys recv(s windows.Handle, buf []byte, flags int32) (n int32, err error) [failretval == -1] = ws2_32.recv

common/bufio/vectorised_unix.go

@@ -38,7 +38,6 @@ func (w *SyscallVectorisedWriter) WriteVectorised(buffers []*buf.Buffer) error {
 	var innerErr unix.Errno
 	err := w.rawConn.Write(func(fd uintptr) (done bool) {
 		//nolint:staticcheck
-		//goland:noinspection GoDeprecation
 		_, _, innerErr = unix.Syscall(unix.SYS_WRITEV, fd, uintptr(unsafe.Pointer(&iovecList[0])), uintptr(len(iovecList)))
 		return innerErr != unix.EAGAIN && innerErr != unix.EWOULDBLOCK
 	})

common/bufio/zsyscall_windows.go

@@ -0,0 +1,57 @@
+// Code generated by 'go generate'; DO NOT EDIT.
+
+package bufio
+
+import (
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+var _ unsafe.Pointer
+
+// Do the interface allocations only once for common
+// Errno values.
+const (
+	errnoERROR_IO_PENDING = 997
+)
+
+var (
+	errERROR_IO_PENDING error = syscall.Errno(errnoERROR_IO_PENDING)
+	errERROR_EINVAL     error = syscall.EINVAL
+)
+
+// errnoErr returns common boxed Errno values, to prevent
+// allocations at runtime.
+func errnoErr(e syscall.Errno) error {
+	switch e {
+	case 0:
+		return errERROR_EINVAL
+	case errnoERROR_IO_PENDING:
+		return errERROR_IO_PENDING
+	}
+	// TODO: add more here, after collecting data on the common
+	// error values see on Windows. (perhaps when running
+	// all.bat?)
+	return e
+}
+
+var (
+	modws2_32 = windows.NewLazySystemDLL("ws2_32.dll")
+
+	procrecv = modws2_32.NewProc("recv")
+)
+
+func recv(s windows.Handle, buf []byte, flags int32) (n int32, err error) {
+	var _p0 *byte
+	if len(buf) > 0 {
+		_p0 = &buf[0]
+	}
+	r0, _, e1 := syscall.Syscall6(procrecv.Addr(), 4, uintptr(s), uintptr(unsafe.Pointer(_p0)), uintptr(len(buf)), uintptr(flags), 0, 0)
+	n = int32(r0)
+	if n == -1 {
+		err = errnoErr(e1)
+	}
+	return
+}

common/canceler/instance.go

@@ -41,9 +41,9 @@ func (i *Instance) Timeout() time.Duration {
 	return i.timeout
 }
 
-func (i *Instance) SetTimeout(timeout time.Duration) {
+func (i *Instance) SetTimeout(timeout time.Duration) bool {
 	i.timeout = timeout
-	i.Update()
+	return i.Update()
 }
 
 func (i *Instance) wait() {

common/canceler/packet.go

@@ -13,7 +13,7 @@ import (
 type PacketConn interface {
 	N.PacketConn
 	Timeout() time.Duration
-	SetTimeout(timeout time.Duration)
+	SetTimeout(timeout time.Duration) bool
 }
 
 type TimerPacketConn struct {
@@ -24,10 +24,12 @@ type TimerPacketConn struct {
 func NewPacketConn(ctx context.Context, conn N.PacketConn, timeout time.Duration) (context.Context, N.PacketConn) {
 	if timeoutConn, isTimeoutConn := common.Cast[PacketConn](conn); isTimeoutConn {
 		oldTimeout := timeoutConn.Timeout()
-		if timeout < oldTimeout {
-			timeoutConn.SetTimeout(timeout)
+		if oldTimeout > 0 && timeout >= oldTimeout {
+			return ctx, conn
+		}
+		if timeoutConn.SetTimeout(timeout) {
+			return ctx, conn
 		}
-		return ctx, conn
 	}
 	err := conn.SetReadDeadline(time.Time{})
 	if err == nil {
@@ -58,8 +60,8 @@ func (c *TimerPacketConn) Timeout() time.Duration {
 	return c.instance.Timeout()
 }
 
-func (c *TimerPacketConn) SetTimeout(timeout time.Duration) {
-	c.instance.SetTimeout(timeout)
+func (c *TimerPacketConn) SetTimeout(timeout time.Duration) bool {
+	return c.instance.SetTimeout(timeout)
 }
 
 func (c *TimerPacketConn) Close() error {

common/canceler/packet_timeout.go

@@ -61,9 +61,9 @@ func (c *TimeoutPacketConn) Timeout() time.Duration {
 	return c.timeout
 }
 
-func (c *TimeoutPacketConn) SetTimeout(timeout time.Duration) {
+func (c *TimeoutPacketConn) SetTimeout(timeout time.Duration) bool {
 	c.timeout = timeout
-	c.PacketConn.SetReadDeadline(time.Now())
+	return c.PacketConn.SetReadDeadline(time.Now()) == nil
 }
 
 func (c *TimeoutPacketConn) Close() error {

common/cond.go

@@ -157,6 +157,18 @@ func IndexIndexed[T any](arr []T, block func(index int, it T) bool) int {
 	return -1
 }
 
+func Equal[S ~[]E, E comparable](s1, s2 S) bool {
+	if len(s1) != len(s2) {
+		return false
+	}
+	for i := range s1 {
+		if s1[i] != s2[i] {
+			return false
+		}
+	}
+	return true
+}
+
 //go:norace
 func Dup[T any](obj T) T {
 	pointer := uintptr(unsafe.Pointer(&obj))
@@ -268,6 +280,14 @@ func Reverse[T any](arr []T) []T {
 	return arr
 }
 
+func ReverseMap[K comparable, V comparable](m map[K]V) map[V]K {
+	ret := make(map[V]K, len(m))
+	for k, v := range m {
+		ret[v] = k
+	}
+	return ret
+}
+
 func Done(ctx context.Context) bool {
 	select {
 	case <-ctx.Done():
@@ -362,24 +382,3 @@ func Close(closers ...any) error {
 	}
 	return retErr
 }
-
-// Deprecated: wtf is this?
-type Starter interface {
-	Start() error
-}
-
-// Deprecated: wtf is this?
-func Start(starters ...any) error {
-	for _, rawStarter := range starters {
-		if rawStarter == nil {
-			continue
-		}
-		if starter, isStarter := rawStarter.(Starter); isStarter {
-			err := starter.Start()
-			if err != nil {
-				return err
-			}
-		}
-	}
-	return nil
-}

common/context.go

@@ -5,6 +5,7 @@ import (
 	"reflect"
 )
 
+// Deprecated: not used
 func SelectContext(contextList []context.Context) (int, error) {
 	if len(contextList) == 1 {
 		<-contextList[0].Done()

common/control/bind_darwin.go

@@ -9,15 +9,15 @@ import (
 
 func bindToInterface(conn syscall.RawConn, network string, address string, finder InterfaceFinder, interfaceName string, interfaceIndex int, preferInterfaceName bool) error {
 	return Raw(conn, func(fd uintptr) error {
-		var err error
 		if interfaceIndex == -1 {
 			if finder == nil {
 				return os.ErrInvalid
 			}
-			interfaceIndex, err = finder.InterfaceIndexByName(interfaceName)
+			iif, err := finder.ByName(interfaceName)
 			if err != nil {
 				return err
 			}
+			interfaceIndex = iif.Index
 		}
 		switch network {
 		case "tcp6", "udp6":

common/control/bind_finder.go

@@ -3,19 +3,57 @@ package control
 import (
 	"net"
 	"net/netip"
+	"unsafe"
+
+	"github.com/sagernet/sing/common"
+	M "github.com/sagernet/sing/common/metadata"
 )
 
 type InterfaceFinder interface {
+	Update() error
 	Interfaces() []Interface
-	InterfaceIndexByName(name string) (int, error)
-	InterfaceNameByIndex(index int) (string, error)
-	InterfaceByAddr(addr netip.Addr) (*Interface, error)
+	ByName(name string) (*Interface, error)
+	ByIndex(index int) (*Interface, error)
+	ByAddr(addr netip.Addr) (*Interface, error)
 }
 
 type Interface struct {
 	Index        int
 	MTU          int
 	Name         string
-	Addresses    []netip.Prefix
 	HardwareAddr net.HardwareAddr
+	Flags        net.Flags
+	Addresses    []netip.Prefix
+}
+
+func (i Interface) Equals(other Interface) bool {
+	return i.Index == other.Index &&
+		i.MTU == other.MTU &&
+		i.Name == other.Name &&
+		common.Equal(i.HardwareAddr, other.HardwareAddr) &&
+		i.Flags == other.Flags &&
+		common.Equal(i.Addresses, other.Addresses)
+}
+
+func (i Interface) NetInterface() net.Interface {
+	return *(*net.Interface)(unsafe.Pointer(&i))
+}
+
+func InterfaceFromNet(iif net.Interface) (Interface, error) {
+	ifAddrs, err := iif.Addrs()
+	if err != nil {
+		return Interface{}, err
+	}
+	return InterfaceFromNetAddrs(iif, common.Map(ifAddrs, M.PrefixFromNet)), nil
+}
+
+func InterfaceFromNetAddrs(iif net.Interface, addresses []netip.Prefix) Interface {
+	return Interface{
+		Index:        iif.Index,
+		MTU:          iif.MTU,
+		Name:         iif.Name,
+		HardwareAddr: iif.HardwareAddr,
+		Flags:        iif.Flags,
+		Addresses:    addresses,
+	}
 }

common/control/bind_finder_default.go

@@ -3,11 +3,8 @@ package control
 import (
 	"net"
 	"net/netip"
-	_ "unsafe"
 
-	"github.com/sagernet/sing/common"
 	E "github.com/sagernet/sing/common/exceptions"
-	M "github.com/sagernet/sing/common/metadata"
 )
 
 var _ InterfaceFinder = (*DefaultInterfaceFinder)(nil)
@@ -27,17 +24,12 @@ func (f *DefaultInterfaceFinder) Update() error {
 	}
 	interfaces := make([]Interface, 0, len(netIfs))
 	for _, netIf := range netIfs {
-		ifAddrs, err := netIf.Addrs()
+		var iif Interface
+		iif, err = InterfaceFromNet(netIf)
 		if err != nil {
 			return err
 		}
-		interfaces = append(interfaces, Interface{
-			Index:        netIf.Index,
-			MTU:          netIf.MTU,
-			Name:         netIf.Name,
-			Addresses:    common.Map(ifAddrs, M.PrefixFromNet),
-			HardwareAddr: netIf.HardwareAddr,
-		})
+		interfaces = append(interfaces, iif)
 	}
 	f.interfaces = interfaces
 	return nil
@@ -51,46 +43,41 @@ func (f *DefaultInterfaceFinder) Interfaces() []Interface {
 	return f.interfaces
 }
 
-func (f *DefaultInterfaceFinder) InterfaceIndexByName(name string) (int, error) {
+func (f *DefaultInterfaceFinder) ByName(name string) (*Interface, error) {
 	for _, netInterface := range f.interfaces {
 		if netInterface.Name == name {
-			return netInterface.Index, nil
+			return &netInterface, nil
 		}
 	}
-	netInterface, err := net.InterfaceByName(name)
-	if err != nil {
-		return 0, err
+	_, err := net.InterfaceByName(name)
+	if err == nil {
+		err = f.Update()
+		if err != nil {
+			return nil, err
+		}
+		return f.ByName(name)
 	}
-	f.Update()
-	return netInterface.Index, nil
+	return nil, &net.OpError{Op: "route", Net: "ip+net", Source: nil, Addr: &net.IPAddr{IP: nil}, Err: E.New("no such network interface")}
 }
 
-func (f *DefaultInterfaceFinder) InterfaceNameByIndex(index int) (string, error) {
+func (f *DefaultInterfaceFinder) ByIndex(index int) (*Interface, error) {
 	for _, netInterface := range f.interfaces {
 		if netInterface.Index == index {
-			return netInterface.Name, nil
+			return &netInterface, nil
 		}
 	}
-	netInterface, err := net.InterfaceByIndex(index)
-	if err != nil {
-		return "", err
+	_, err := net.InterfaceByIndex(index)
+	if err == nil {
+		err = f.Update()
+		if err != nil {
+			return nil, err
+		}
+		return f.ByIndex(index)
 	}
-	f.Update()
-	return netInterface.Name, nil
+	return nil, &net.OpError{Op: "route", Net: "ip+net", Source: nil, Addr: &net.IPAddr{IP: nil}, Err: E.New("no such network interface")}
 }
 
-func (f *DefaultInterfaceFinder) InterfaceByAddr(addr netip.Addr) (*Interface, error) {
-	for _, netInterface := range f.interfaces {
-		for _, prefix := range netInterface.Addresses {
-			if prefix.Contains(addr) {
-				return &netInterface, nil
-			}
-		}
-	}
-	err := f.Update()
-	if err != nil {
-		return nil, err
-	}
+func (f *DefaultInterfaceFinder) ByAddr(addr netip.Addr) (*Interface, error) {
 	for _, netInterface := range f.interfaces {
 		for _, prefix := range netInterface.Addresses {
 			if prefix.Contains(addr) {

common/control/bind_linux.go

@@ -19,11 +19,11 @@ func bindToInterface(conn syscall.RawConn, network string, address string, finde
 				if interfaceName == "" {
 					return os.ErrInvalid
 				}
-				var err error
-				interfaceIndex, err = finder.InterfaceIndexByName(interfaceName)
+				iif, err := finder.ByName(interfaceName)
 				if err != nil {
 					return err
 				}
+				interfaceIndex = iif.Index
 			}
 			err := unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_BINDTOIFINDEX, interfaceIndex)
 			if err == nil {

common/control/bind_windows.go

@@ -11,19 +11,19 @@ import (
 
 func bindToInterface(conn syscall.RawConn, network string, address string, finder InterfaceFinder, interfaceName string, interfaceIndex int, preferInterfaceName bool) error {
 	return Raw(conn, func(fd uintptr) error {
-		var err error
 		if interfaceIndex == -1 {
 			if finder == nil {
 				return os.ErrInvalid
 			}
-			interfaceIndex, err = finder.InterfaceIndexByName(interfaceName)
+			iif, err := finder.ByName(interfaceName)
 			if err != nil {
 				return err
 			}
+			interfaceIndex = iif.Index
 		}
 		handle := syscall.Handle(fd)
 		if M.ParseSocksaddr(address).AddrString() == "" {
-			err = bind4(handle, interfaceIndex)
+			err := bind4(handle, interfaceIndex)
 			if err != nil {
 				return err
 			}

common/control/frag_darwin.go

@@ -4,19 +4,26 @@ import (
 	"os"
 	"syscall"
 
+	N "github.com/sagernet/sing/common/network"
+
 	"golang.org/x/sys/unix"
 )
 
 func DisableUDPFragment() Func {
 	return func(network, address string, conn syscall.RawConn) error {
+		if N.NetworkName(network) != N.NetworkUDP {
+			return nil
+		}
 		return Raw(conn, func(fd uintptr) error {
-			switch network {
-			case "udp4":
-				if err := unix.SetsockoptInt(int(fd), unix.IPPROTO_IP, unix.IP_DONTFRAG, 1); err != nil {
+			if network == "udp" || network == "udp4" {
+				err := unix.SetsockoptInt(int(fd), unix.IPPROTO_IP, unix.IP_DONTFRAG, 1)
+				if err != nil {
 					return os.NewSyscallError("SETSOCKOPT IP_DONTFRAG", err)
 				}
-			case "udp6":
-				if err := unix.SetsockoptInt(int(fd), unix.IPPROTO_IPV6, unix.IPV6_DONTFRAG, 1); err != nil {
+			}
+			if network == "udp" || network == "udp6" {
+				err := unix.SetsockoptInt(int(fd), unix.IPPROTO_IPV6, unix.IPV6_DONTFRAG, 1)
+				if err != nil {
 					return os.NewSyscallError("SETSOCKOPT IPV6_DONTFRAG", err)
 				}
 			}

common/control/frag_linux.go

@@ -11,17 +11,19 @@ import (
 
 func DisableUDPFragment() Func {
 	return func(network, address string, conn syscall.RawConn) error {
-		switch N.NetworkName(network) {
-		case N.NetworkUDP:
-		default:
+		if N.NetworkName(network) != N.NetworkUDP {
 			return nil
 		}
 		return Raw(conn, func(fd uintptr) error {
-			if err := unix.SetsockoptInt(int(fd), unix.IPPROTO_IP, unix.IP_MTU_DISCOVER, unix.IP_PMTUDISC_DO); err != nil {
-				return os.NewSyscallError("SETSOCKOPT IP_MTU_DISCOVER IP_PMTUDISC_DO", err)
+			if network == "udp" || network == "udp4" {
+				err := unix.SetsockoptInt(int(fd), unix.IPPROTO_IP, unix.IP_MTU_DISCOVER, unix.IP_PMTUDISC_DO)
+				if err != nil {
+					return os.NewSyscallError("SETSOCKOPT IP_MTU_DISCOVER IP_PMTUDISC_DO", err)
+				}
 			}
-			if network == "udp6" {
-				if err := unix.SetsockoptInt(int(fd), unix.IPPROTO_IPV6, unix.IPV6_MTU_DISCOVER, unix.IP_PMTUDISC_DO); err != nil {
+			if network == "udp" || network == "udp6" {
+				err := unix.SetsockoptInt(int(fd), unix.IPPROTO_IPV6, unix.IPV6_MTU_DISCOVER, unix.IP_PMTUDISC_DO)
+				if err != nil {
 					return os.NewSyscallError("SETSOCKOPT IPV6_MTU_DISCOVER IP_PMTUDISC_DO", err)
 				}
 			}

common/control/frag_windows.go

@@ -25,17 +25,19 @@ const (
 
 func DisableUDPFragment() Func {
 	return func(network, address string, conn syscall.RawConn) error {
-		switch N.NetworkName(network) {
-		case N.NetworkUDP:
-		default:
+		if N.NetworkName(network) != N.NetworkUDP {
 			return nil
 		}
 		return Raw(conn, func(fd uintptr) error {
-			if err := windows.SetsockoptInt(windows.Handle(fd), windows.IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_DO); err != nil {
-				return os.NewSyscallError("SETSOCKOPT IP_MTU_DISCOVER IP_PMTUDISC_DO", err)
+			if network == "udp" || network == "udp4" {
+				err := windows.SetsockoptInt(windows.Handle(fd), windows.IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_DO)
+				if err != nil {
+					return os.NewSyscallError("SETSOCKOPT IP_MTU_DISCOVER IP_PMTUDISC_DO", err)
+				}
 			}
-			if network == "udp6" {
-				if err := windows.SetsockoptInt(windows.Handle(fd), windows.IPPROTO_IPV6, IPV6_MTU_DISCOVER, IP_PMTUDISC_DO); err != nil {
+			if network == "udp" || network == "udp6" {
+				err := windows.SetsockoptInt(windows.Handle(fd), windows.IPPROTO_IPV6, IPV6_MTU_DISCOVER, IP_PMTUDISC_DO)
+				if err != nil {
 					return os.NewSyscallError("SETSOCKOPT IPV6_MTU_DISCOVER IP_PMTUDISC_DO", err)
 				}
 			}

common/exceptions/cause.go

@@ -12,3 +12,16 @@ func (e *causeError) Error() string {
 func (e *causeError) Unwrap() error {
 	return e.cause
 }
+
+type causeError1 struct {
+	error
+	cause error
+}
+
+func (e *causeError1) Error() string {
+	return e.error.Error() + ": " + e.cause.Error()
+}
+
+func (e *causeError1) Unwrap() []error {
+	return []error{e.error, e.cause}
+}

common/exceptions/error.go

@@ -12,6 +12,7 @@ import (
 	F "github.com/sagernet/sing/common/format"
 )
 
+// Deprecated: wtf is this?
 type Handler interface {
 	NewError(ctx context.Context, err error)
 }
@@ -31,6 +32,13 @@ func Cause(cause error, message ...any) error {
 	return &causeError{F.ToString(message...), cause}
 }
 
+func Cause1(err error, cause error) error {
+	if cause == nil {
+		panic("cause on an nil error")
+	}
+	return &causeError1{err, cause}
+}
+
 func Extend(cause error, message ...any) error {
 	if cause == nil {
 		panic("extend on an nil error")
@@ -39,11 +47,11 @@ func Extend(cause error, message ...any) error {
 }
 
 func IsClosedOrCanceled(err error) bool {
-	return IsMulti(err, io.EOF, net.ErrClosed, io.ErrClosedPipe, os.ErrClosed, syscall.EPIPE, syscall.ECONNRESET, context.Canceled, context.DeadlineExceeded)
+	return IsClosed(err) || IsCanceled(err) || IsTimeout(err)
 }
 
 func IsClosed(err error) bool {
-	return IsMulti(err, io.EOF, net.ErrClosed, io.ErrClosedPipe, os.ErrClosed, syscall.EPIPE, syscall.ECONNRESET)
+	return IsMulti(err, io.EOF, net.ErrClosed, io.ErrClosedPipe, os.ErrClosed, syscall.EPIPE, syscall.ECONNRESET, syscall.ENOTCONN)
 }
 
 func IsCanceled(err error) bool {

common/exceptions/inner.go

@@ -1,24 +1,14 @@
 package exceptions
 
-import "github.com/sagernet/sing/common"
+import (
+	"errors"
 
-type HasInnerError interface {
-	Unwrap() error
-}
+	"github.com/sagernet/sing/common"
+)
 
+// Deprecated: Use errors.Unwrap instead.
 func Unwrap(err error) error {
-	for {
-		inner, ok := err.(HasInnerError)
-		if !ok {
-			break
-		}
-		innerErr := inner.Unwrap()
-		if innerErr == nil {
-			break
-		}
-		err = innerErr
-	}
-	return err
+	return errors.Unwrap(err)
 }
 
 func Cast[T any](err error) (T, bool) {

common/exceptions/multi.go

@@ -63,12 +63,5 @@ func IsMulti(err error, targetList ...error) bool {
 			return true
 		}
 	}
-	err = Unwrap(err)
-	multiErr, isMulti := err.(MultiError)
-	if !isMulti {
-		return false
-	}
-	return common.All(multiErr.Unwrap(), func(it error) bool {
-		return IsMulti(it, targetList...)
-	})
+	return false
 }

common/exceptions/timeout.go

@@ -1,17 +1,21 @@
 package exceptions
 
-import "net"
+import (
+	"errors"
+	"net"
+)
 
 type TimeoutError interface {
 	Timeout() bool
 }
 
 func IsTimeout(err error) bool {
-	if netErr, isNetErr := err.(net.Error); isNetErr {
-		//goland:noinspection GoDeprecation
+	var netErr net.Error
+	if errors.As(err, &netErr) {
 		//nolint:staticcheck
 		return netErr.Temporary() && netErr.Timeout()
-	} else if timeoutErr, isTimeout := Cast[TimeoutError](err); isTimeout {
+	}
+	if timeoutErr, isTimeout := Cast[TimeoutError](err); isTimeout {
 		return timeoutErr.Timeout()
 	}
 	return false

common/json/badjson/json.go

@@ -2,13 +2,14 @@ package badjson
 
 import (
 	"bytes"
+	"context"
 
 	E "github.com/sagernet/sing/common/exceptions"
 	"github.com/sagernet/sing/common/json"
 )
 
-func Decode(content []byte) (any, error) {
-	decoder := json.NewDecoder(bytes.NewReader(content))
+func Decode(ctx context.Context, content []byte) (any, error) {
+	decoder := json.NewDecoderContext(ctx, bytes.NewReader(content))
 	return decodeJSON(decoder)
 }
 

common/json/badjson/merge.go

@@ -1,6 +1,7 @@
 package badjson
 
 import (
+	"context"
 	"os"
 	"reflect"
 
@@ -9,75 +10,75 @@ import (
 	"github.com/sagernet/sing/common/json"
 )
 
-func Omitempty[T any](value T) (T, error) {
-	objectContent, err := json.Marshal(value)
+func Omitempty[T any](ctx context.Context, value T) (T, error) {
+	objectContent, err := json.MarshalContext(ctx, value)
 	if err != nil {
 		return common.DefaultValue[T](), E.Cause(err, "marshal object")
 	}
-	rawNewObject, err := Decode(objectContent)
+	rawNewObject, err := Decode(ctx, objectContent)
 	if err != nil {
 		return common.DefaultValue[T](), err
 	}
-	newObjectContent, err := json.Marshal(rawNewObject)
+	newObjectContent, err := json.MarshalContext(ctx, rawNewObject)
 	if err != nil {
 		return common.DefaultValue[T](), E.Cause(err, "marshal new object")
 	}
 	var newObject T
-	err = json.Unmarshal(newObjectContent, &newObject)
+	err = json.UnmarshalContext(ctx, newObjectContent, &newObject)
 	if err != nil {
 		return common.DefaultValue[T](), E.Cause(err, "unmarshal new object")
 	}
 	return newObject, nil
 }
 
-func Merge[T any](source T, destination T, disableAppend bool) (T, error) {
-	rawSource, err := json.Marshal(source)
+func Merge[T any](ctx context.Context, source T, destination T, disableAppend bool) (T, error) {
+	rawSource, err := json.MarshalContext(ctx, source)
 	if err != nil {
 		return common.DefaultValue[T](), E.Cause(err, "marshal source")
 	}
-	rawDestination, err := json.Marshal(destination)
+	rawDestination, err := json.MarshalContext(ctx, destination)
 	if err != nil {
 		return common.DefaultValue[T](), E.Cause(err, "marshal destination")
 	}
-	return MergeFrom[T](rawSource, rawDestination, disableAppend)
+	return MergeFrom[T](ctx, rawSource, rawDestination, disableAppend)
 }
 
-func MergeFromSource[T any](rawSource json.RawMessage, destination T, disableAppend bool) (T, error) {
+func MergeFromSource[T any](ctx context.Context, rawSource json.RawMessage, destination T, disableAppend bool) (T, error) {
 	if rawSource == nil {
 		return destination, nil
 	}
-	rawDestination, err := json.Marshal(destination)
+	rawDestination, err := json.MarshalContext(ctx, destination)
 	if err != nil {
 		return common.DefaultValue[T](), E.Cause(err, "marshal destination")
 	}
-	return MergeFrom[T](rawSource, rawDestination, disableAppend)
+	return MergeFrom[T](ctx, rawSource, rawDestination, disableAppend)
 }
 
-func MergeFromDestination[T any](source T, rawDestination json.RawMessage, disableAppend bool) (T, error) {
+func MergeFromDestination[T any](ctx context.Context, source T, rawDestination json.RawMessage, disableAppend bool) (T, error) {
 	if rawDestination == nil {
 		return source, nil
 	}
-	rawSource, err := json.Marshal(source)
+	rawSource, err := json.MarshalContext(ctx, source)
 	if err != nil {
 		return common.DefaultValue[T](), E.Cause(err, "marshal source")
 	}
-	return MergeFrom[T](rawSource, rawDestination, disableAppend)
+	return MergeFrom[T](ctx, rawSource, rawDestination, disableAppend)
 }
 
-func MergeFrom[T any](rawSource json.RawMessage, rawDestination json.RawMessage, disableAppend bool) (T, error) {
-	rawMerged, err := MergeJSON(rawSource, rawDestination, disableAppend)
+func MergeFrom[T any](ctx context.Context, rawSource json.RawMessage, rawDestination json.RawMessage, disableAppend bool) (T, error) {
+	rawMerged, err := MergeJSON(ctx, rawSource, rawDestination, disableAppend)
 	if err != nil {
 		return common.DefaultValue[T](), E.Cause(err, "merge options")
 	}
 	var merged T
-	err = json.Unmarshal(rawMerged, &merged)
+	err = json.UnmarshalContext(ctx, rawMerged, &merged)
 	if err != nil {
 		return common.DefaultValue[T](), E.Cause(err, "unmarshal merged options")
 	}
 	return merged, nil
 }
 
-func MergeJSON(rawSource json.RawMessage, rawDestination json.RawMessage, disableAppend bool) (json.RawMessage, error) {
+func MergeJSON(ctx context.Context, rawSource json.RawMessage, rawDestination json.RawMessage, disableAppend bool) (json.RawMessage, error) {
 	if rawSource == nil && rawDestination == nil {
 		return nil, os.ErrInvalid
 	} else if rawSource == nil {
@@ -85,16 +86,16 @@ func MergeJSON(rawSource json.RawMessage, rawDestination json.RawMessage, disabl
 	} else if rawDestination == nil {
 		return rawSource, nil
 	}
-	source, err := Decode(rawSource)
+	source, err := Decode(ctx, rawSource)
 	if err != nil {
 		return nil, E.Cause(err, "decode source")
 	}
-	destination, err := Decode(rawDestination)
+	destination, err := Decode(ctx, rawDestination)
 	if err != nil {
 		return nil, E.Cause(err, "decode destination")
 	}
 	if source == nil {
-		return json.Marshal(destination)
+		return json.MarshalContext(ctx, destination)
 	} else if destination == nil {
 		return json.Marshal(source)
 	}
@@ -102,7 +103,7 @@ func MergeJSON(rawSource json.RawMessage, rawDestination json.RawMessage, disabl
 	if err != nil {
 		return nil, err
 	}
-	return json.Marshal(merged)
+	return json.MarshalContext(ctx, merged)
 }
 
 func mergeJSON(anySource any, anyDestination any, disableAppend bool) (any, error) {

common/json/badjson/merge_objects.go

@@ -0,0 +1,68 @@
+package badjson
+
+import (
+	"context"
+	"reflect"
+
+	E "github.com/sagernet/sing/common/exceptions"
+	"github.com/sagernet/sing/common/json"
+	cJSON "github.com/sagernet/sing/common/json/internal/contextjson"
+)
+
+func MarshallObjects(objects ...any) ([]byte, error) {
+	return MarshallObjectsContext(context.Background(), objects...)
+}
+
+func MarshallObjectsContext(ctx context.Context, objects ...any) ([]byte, error) {
+	if len(objects) == 1 {
+		return json.Marshal(objects[0])
+	}
+	var content JSONObject
+	for _, object := range objects {
+		objectMap, err := newJSONObject(ctx, object)
+		if err != nil {
+			return nil, err
+		}
+		content.PutAll(objectMap)
+	}
+	return content.MarshalJSONContext(ctx)
+}
+
+func UnmarshallExcluded(inputContent []byte, parentObject any, object any) error {
+	return UnmarshallExcludedContext(context.Background(), inputContent, parentObject, object)
+}
+
+func UnmarshallExcludedContext(ctx context.Context, inputContent []byte, parentObject any, object any) error {
+	var content JSONObject
+	err := content.UnmarshalJSONContext(ctx, inputContent)
+	if err != nil {
+		return err
+	}
+	for _, key := range cJSON.ObjectKeys(reflect.TypeOf(parentObject)) {
+		content.Remove(key)
+	}
+	if object == nil {
+		if content.IsEmpty() {
+			return nil
+		}
+		return E.New("unexpected key: ", content.Keys()[0])
+	}
+	inputContent, err = content.MarshalJSONContext(ctx)
+	if err != nil {
+		return err
+	}
+	return json.UnmarshalContextDisallowUnknownFields(ctx, inputContent, object)
+}
+
+func newJSONObject(ctx context.Context, object any) (*JSONObject, error) {
+	inputContent, err := json.MarshalContext(ctx, object)
+	if err != nil {
+		return nil, err
+	}
+	var content JSONObject
+	err = content.UnmarshalJSONContext(ctx, inputContent)
+	if err != nil {
+		return nil, err
+	}
+	return &content, nil
+}

common/json/badjson/object.go

@@ -2,6 +2,7 @@ package badjson
 
 import (
 	"bytes"
+	"context"
 	"strings"
 
 	"github.com/sagernet/sing/common"
@@ -28,6 +29,10 @@ func (m *JSONObject) IsEmpty() bool {
 }
 
 func (m *JSONObject) MarshalJSON() ([]byte, error) {
+	return m.MarshalJSONContext(context.Background())
+}
+
+func (m *JSONObject) MarshalJSONContext(ctx context.Context) ([]byte, error) {
 	buffer := new(bytes.Buffer)
 	buffer.WriteString("{")
 	items := common.Filter(m.Entries(), func(it collections.MapEntry[string, any]) bool {
@@ -38,13 +43,13 @@ func (m *JSONObject) MarshalJSON() ([]byte, error) {
 	})
 	iLen := len(items)
 	for i, entry := range items {
-		keyContent, err := json.Marshal(entry.Key)
+		keyContent, err := json.MarshalContext(ctx, entry.Key)
 		if err != nil {
 			return nil, err
 		}
 		buffer.WriteString(strings.TrimSpace(string(keyContent)))
 		buffer.WriteString(": ")
-		valueContent, err := json.Marshal(entry.Value)
+		valueContent, err := json.MarshalContext(ctx, entry.Value)
 		if err != nil {
 			return nil, err
 		}
@@ -58,7 +63,11 @@ func (m *JSONObject) MarshalJSON() ([]byte, error) {
 }
 
 func (m *JSONObject) UnmarshalJSON(content []byte) error {
-	decoder := json.NewDecoder(bytes.NewReader(content))
+	return m.UnmarshalJSONContext(context.Background(), content)
+}
+
+func (m *JSONObject) UnmarshalJSONContext(ctx context.Context, content []byte) error {
+	decoder := json.NewDecoderContext(ctx, bytes.NewReader(content))
 	m.Clear()
 	objectStart, err := decoder.Token()
 	if err != nil {

common/json/badjson/typed.go

@@ -2,6 +2,7 @@ package badjson
 
 import (
 	"bytes"
+	"context"
 	"strings"
 
 	E "github.com/sagernet/sing/common/exceptions"
@@ -14,18 +15,22 @@ type TypedMap[K comparable, V any] struct {
 }
 
 func (m TypedMap[K, V]) MarshalJSON() ([]byte, error) {
+	return m.MarshalJSONContext(context.Background())
+}
+
+func (m TypedMap[K, V]) MarshalJSONContext(ctx context.Context) ([]byte, error) {
 	buffer := new(bytes.Buffer)
 	buffer.WriteString("{")
 	items := m.Entries()
 	iLen := len(items)
 	for i, entry := range items {
-		keyContent, err := json.Marshal(entry.Key)
+		keyContent, err := json.MarshalContext(ctx, entry.Key)
 		if err != nil {
 			return nil, err
 		}
 		buffer.WriteString(strings.TrimSpace(string(keyContent)))
 		buffer.WriteString(": ")
-		valueContent, err := json.Marshal(entry.Value)
+		valueContent, err := json.MarshalContext(ctx, entry.Value)
 		if err != nil {
 			return nil, err
 		}
@@ -39,7 +44,11 @@ func (m TypedMap[K, V]) MarshalJSON() ([]byte, error) {
 }
 
 func (m *TypedMap[K, V]) UnmarshalJSON(content []byte) error {
-	decoder := json.NewDecoder(bytes.NewReader(content))
+	return m.UnmarshalJSONContext(context.Background(), content)
+}
+
+func (m *TypedMap[K, V]) UnmarshalJSONContext(ctx context.Context, content []byte) error {
+	decoder := json.NewDecoderContext(ctx, bytes.NewReader(content))
 	m.Clear()
 	objectStart, err := decoder.Token()
 	if err != nil {
@@ -47,7 +56,7 @@ func (m *TypedMap[K, V]) UnmarshalJSON(content []byte) error {
 	} else if objectStart != json.Delim('{') {
 		return E.New("expected json object start, but starts with ", objectStart)
 	}
-	err = m.decodeJSON(decoder)
+	err = m.decodeJSON(ctx, decoder)
 	if err != nil {
 		return E.Cause(err, "decode json object content")
 	}
@@ -60,18 +69,18 @@ func (m *TypedMap[K, V]) UnmarshalJSON(content []byte) error {
 	return nil
 }
 
-func (m *TypedMap[K, V]) decodeJSON(decoder *json.Decoder) error {
+func (m *TypedMap[K, V]) decodeJSON(ctx context.Context, decoder *json.Decoder) error {
 	for decoder.More() {
 		keyToken, err := decoder.Token()
 		if err != nil {
 			return err
 		}
-		keyContent, err := json.Marshal(keyToken)
+		keyContent, err := json.MarshalContext(ctx, keyToken)
 		if err != nil {
 			return err
 		}
 		var entryKey K
-		err = json.Unmarshal(keyContent, &entryKey)
+		err = json.UnmarshalContext(ctx, keyContent, &entryKey)
 		if err != nil {
 			return err
 		}

common/json/badoption/duration.go

@@ -0,0 +1,32 @@
+package badoption
+
+import (
+	"time"
+
+	"github.com/sagernet/sing/common/json"
+	"github.com/sagernet/sing/common/json/badoption/internal/my_time"
+)
+
+type Duration time.Duration
+
+func (d Duration) Build() time.Duration {
+	return time.Duration(d)
+}
+
+func (d Duration) MarshalJSON() ([]byte, error) {
+	return json.Marshal((time.Duration)(d).String())
+}
+
+func (d *Duration) UnmarshalJSON(bytes []byte) error {
+	var value string
+	err := json.Unmarshal(bytes, &value)
+	if err != nil {
+		return err
+	}
+	duration, err := my_time.ParseDuration(value)
+	if err != nil {
+		return err
+	}
+	*d = Duration(duration)
+	return nil
+}

common/json/badoption/http.go

@@ -0,0 +1,15 @@
+package badoption
+
+import "net/http"
+
+type HTTPHeader map[string]Listable[string]
+
+func (h HTTPHeader) Build() http.Header {
+	header := make(http.Header)
+	for name, values := range h {
+		for _, value := range values {
+			header.Add(name, value)
+		}
+	}
+	return header
+}

common/json/badoption/internal/my_time/format.go

@@ -0,0 +1,226 @@
+package my_time
+
+import (
+	"errors"
+	"time"
+)
+
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+const durationDay = 24 * time.Hour
+
+var unitMap = map[string]uint64{
+	"ns": uint64(time.Nanosecond),
+	"us": uint64(time.Microsecond),
+	"µs": uint64(time.Microsecond), // U+00B5 = micro symbol
+	"μs": uint64(time.Microsecond), // U+03BC = Greek letter mu
+	"ms": uint64(time.Millisecond),
+	"s":  uint64(time.Second),
+	"m":  uint64(time.Minute),
+	"h":  uint64(time.Hour),
+	"d":  uint64(durationDay),
+}
+
+// ParseDuration parses a duration string.
+// A duration string is a possibly signed sequence of
+// decimal numbers, each with optional fraction and a unit suffix,
+// such as "300ms", "-1.5h" or "2h45m".
+// Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h".
+func ParseDuration(s string) (time.Duration, error) {
+	// [-+]?([0-9]*(\.[0-9]*)?[a-z]+)+
+	orig := s
+	var d uint64
+	neg := false
+
+	// Consume [-+]?
+	if s != "" {
+		c := s[0]
+		if c == '-' || c == '+' {
+			neg = c == '-'
+			s = s[1:]
+		}
+	}
+	// Special case: if all that is left is "0", this is zero.
+	if s == "0" {
+		return 0, nil
+	}
+	if s == "" {
+		return 0, errors.New("time: invalid duration " + quote(orig))
+	}
+	for s != "" {
+		var (
+			v, f  uint64      // integers before, after decimal point
+			scale float64 = 1 // value = v + f/scale
+		)
+
+		var err error
+
+		// The next character must be [0-9.]
+		if !(s[0] == '.' || '0' <= s[0] && s[0] <= '9') {
+			return 0, errors.New("time: invalid duration " + quote(orig))
+		}
+		// Consume [0-9]*
+		pl := len(s)
+		v, s, err = leadingInt(s)
+		if err != nil {
+			return 0, errors.New("time: invalid duration " + quote(orig))
+		}
+		pre := pl != len(s) // whether we consumed anything before a period
+
+		// Consume (\.[0-9]*)?
+		post := false
+		if s != "" && s[0] == '.' {
+			s = s[1:]
+			pl := len(s)
+			f, scale, s = leadingFraction(s)
+			post = pl != len(s)
+		}
+		if !pre && !post {
+			// no digits (e.g. ".s" or "-.s")
+			return 0, errors.New("time: invalid duration " + quote(orig))
+		}
+
+		// Consume unit.
+		i := 0
+		for ; i < len(s); i++ {
+			c := s[i]
+			if c == '.' || '0' <= c && c <= '9' {
+				break
+			}
+		}
+		if i == 0 {
+			return 0, errors.New("time: missing unit in duration " + quote(orig))
+		}
+		u := s[:i]
+		s = s[i:]
+		unit, ok := unitMap[u]
+		if !ok {
+			return 0, errors.New("time: unknown unit " + quote(u) + " in duration " + quote(orig))
+		}
+		if v > 1<<63/unit {
+			// overflow
+			return 0, errors.New("time: invalid duration " + quote(orig))
+		}
+		v *= unit
+		if f > 0 {
+			// float64 is needed to be nanosecond accurate for fractions of hours.
+			// v >= 0 && (f*unit/scale) <= 3.6e+12 (ns/h, h is the largest unit)
+			v += uint64(float64(f) * (float64(unit) / scale))
+			if v > 1<<63 {
+				// overflow
+				return 0, errors.New("time: invalid duration " + quote(orig))
+			}
+		}
+		d += v
+		if d > 1<<63 {
+			return 0, errors.New("time: invalid duration " + quote(orig))
+		}
+	}
+	if neg {
+		return -time.Duration(d), nil
+	}
+	if d > 1<<63-1 {
+		return 0, errors.New("time: invalid duration " + quote(orig))
+	}
+	return time.Duration(d), nil
+}
+
+var errLeadingInt = errors.New("time: bad [0-9]*") // never printed
+
+// leadingInt consumes the leading [0-9]* from s.
+func leadingInt[bytes []byte | string](s bytes) (x uint64, rem bytes, err error) {
+	i := 0
+	for ; i < len(s); i++ {
+		c := s[i]
+		if c < '0' || c > '9' {
+			break
+		}
+		if x > 1<<63/10 {
+			// overflow
+			return 0, rem, errLeadingInt
+		}
+		x = x*10 + uint64(c) - '0'
+		if x > 1<<63 {
+			// overflow
+			return 0, rem, errLeadingInt
+		}
+	}
+	return x, s[i:], nil
+}
+
+// leadingFraction consumes the leading [0-9]* from s.
+// It is used only for fractions, so does not return an error on overflow,
+// it just stops accumulating precision.
+func leadingFraction(s string) (x uint64, scale float64, rem string) {
+	i := 0
+	scale = 1
+	overflow := false
+	for ; i < len(s); i++ {
+		c := s[i]
+		if c < '0' || c > '9' {
+			break
+		}
+		if overflow {
+			continue
+		}
+		if x > (1<<63-1)/10 {
+			// It's possible for overflow to give a positive number, so take care.
+			overflow = true
+			continue
+		}
+		y := x*10 + uint64(c) - '0'
+		if y > 1<<63 {
+			overflow = true
+			continue
+		}
+		x = y
+		scale *= 10
+	}
+	return x, scale, s[i:]
+}
+
+// These are borrowed from unicode/utf8 and strconv and replicate behavior in
+// that package, since we can't take a dependency on either.
+const (
+	lowerhex  = "0123456789abcdef"
+	runeSelf  = 0x80
+	runeError = '\uFFFD'
+)
+
+func quote(s string) string {
+	buf := make([]byte, 1, len(s)+2) // slice will be at least len(s) + quotes
+	buf[0] = '"'
+	for i, c := range s {
+		if c >= runeSelf || c < ' ' {
+			// This means you are asking us to parse a time.Duration or
+			// time.Location with unprintable or non-ASCII characters in it.
+			// We don't expect to hit this case very often. We could try to
+			// reproduce strconv.Quote's behavior with full fidelity but
+			// given how rarely we expect to hit these edge cases, speed and
+			// conciseness are better.
+			var width int
+			if c == runeError {
+				width = 1
+				if i+2 < len(s) && s[i:i+3] == string(runeError) {
+					width = 3
+				}
+			} else {
+				width = len(string(c))
+			}
+			for j := 0; j < width; j++ {
+				buf = append(buf, `\x`...)
+				buf = append(buf, lowerhex[s[i+j]>>4])
+				buf = append(buf, lowerhex[s[i+j]&0xF])
+			}
+		} else {
+			if c == '"' || c == '\\' {
+				buf = append(buf, '\\')
+			}
+			buf = append(buf, string(c)...)
+		}
+	}
+	buf = append(buf, '"')
+	return string(buf)
+}

common/json/badoption/listable.go

@@ -0,0 +1,35 @@
+package badoption
+
+import (
+	"context"
+
+	E "github.com/sagernet/sing/common/exceptions"
+	"github.com/sagernet/sing/common/json"
+)
+
+type Listable[T any] []T
+
+func (l Listable[T]) MarshalJSONContext(ctx context.Context) ([]byte, error) {
+	arrayList := []T(l)
+	if len(arrayList) == 1 {
+		return json.Marshal(arrayList[0])
+	}
+	return json.MarshalContext(ctx, arrayList)
+}
+
+func (l *Listable[T]) UnmarshalJSONContext(ctx context.Context, content []byte) error {
+	if string(content) == "null" {
+		return nil
+	}
+	var singleItem T
+	err := json.UnmarshalContextDisallowUnknownFields(ctx, content, &singleItem)
+	if err == nil {
+		*l = []T{singleItem}
+		return nil
+	}
+	newErr := json.UnmarshalContextDisallowUnknownFields(ctx, content, (*[]T)(l))
+	if newErr == nil {
+		return nil
+	}
+	return E.Errors(err, newErr)
+}

common/json/badoption/netip.go

@@ -0,0 +1,98 @@
+package badoption
+
+import (
+	"net/netip"
+
+	"github.com/sagernet/sing/common/json"
+)
+
+type Addr netip.Addr
+
+func (a *Addr) Build(defaultAddr netip.Addr) netip.Addr {
+	if a == nil {
+		return defaultAddr
+	}
+	return netip.Addr(*a)
+}
+
+func (a *Addr) MarshalJSON() ([]byte, error) {
+	return json.Marshal(netip.Addr(*a).String())
+}
+
+func (a *Addr) UnmarshalJSON(content []byte) error {
+	var value string
+	err := json.Unmarshal(content, &value)
+	if err != nil {
+		return err
+	}
+	addr, err := netip.ParseAddr(value)
+	if err != nil {
+		return err
+	}
+	*a = Addr(addr)
+	return nil
+}
+
+type Prefix netip.Prefix
+
+func (p *Prefix) Build(defaultPrefix netip.Prefix) netip.Prefix {
+	if p == nil {
+		return defaultPrefix
+	}
+	return netip.Prefix(*p)
+}
+
+func (p *Prefix) MarshalJSON() ([]byte, error) {
+	return json.Marshal(netip.Prefix(*p).String())
+}
+
+func (p *Prefix) UnmarshalJSON(content []byte) error {
+	var value string
+	err := json.Unmarshal(content, &value)
+	if err != nil {
+		return err
+	}
+	prefix, err := netip.ParsePrefix(value)
+	if err != nil {
+		return err
+	}
+	*p = Prefix(prefix)
+	return nil
+}
+
+type Prefixable netip.Prefix
+
+func (p *Prefixable) Build(defaultPrefix netip.Prefix) netip.Prefix {
+	if p == nil {
+		return defaultPrefix
+	}
+	return netip.Prefix(*p)
+}
+
+func (p *Prefixable) MarshalJSON() ([]byte, error) {
+	prefix := netip.Prefix(*p)
+	if prefix.Bits() == prefix.Addr().BitLen() {
+		return json.Marshal(prefix.Addr().String())
+	} else {
+		return json.Marshal(prefix.String())
+	}
+}
+
+func (p *Prefixable) UnmarshalJSON(content []byte) error {
+	var value string
+	err := json.Unmarshal(content, &value)
+	if err != nil {
+		return err
+	}
+	prefix, prefixErr := netip.ParsePrefix(value)
+	if prefixErr == nil {
+		*p = Prefixable(prefix)
+		return nil
+	}
+	addr, addrErr := netip.ParseAddr(value)
+	if addrErr == nil {
+		*p = Prefixable(netip.PrefixFrom(addr, addr.BitLen()))
+		return nil
+	}
+	return prefixErr
+}

common/json/badoption/regexp.go

@@ -0,0 +1,31 @@
+package badoption
+
+import (
+	"regexp"
+
+	"github.com/sagernet/sing/common/json"
+)
+
+type Regexp regexp.Regexp
+
+func (r *Regexp) Build() *regexp.Regexp {
+	return (*regexp.Regexp)(r)
+}
+
+func (r *Regexp) MarshalJSON() ([]byte, error) {
+	return json.Marshal((*regexp.Regexp)(r).String())
+}
+
+func (r *Regexp) UnmarshalJSON(content []byte) error {
+	var stringValue string
+	err := json.Unmarshal(content, &stringValue)
+	if err != nil {
+		return err
+	}
+	regex, err := regexp.Compile(stringValue)
+	if err != nil {
+		return err
+	}
+	*r = Regexp(*regex)
+	return nil
+}

common/json/context_ext.go

@@ -0,0 +1,23 @@
+package json
+
+import (
+	"context"
+
+	"github.com/sagernet/sing/common/json/internal/contextjson"
+)
+
+var (
+	MarshalContext                        = json.MarshalContext
+	UnmarshalContext                      = json.UnmarshalContext
+	NewEncoderContext                     = json.NewEncoderContext
+	NewDecoderContext                     = json.NewDecoderContext
+	UnmarshalContextDisallowUnknownFields = json.UnmarshalContextDisallowUnknownFields
+)
+
+type ContextMarshaler interface {
+	MarshalJSONContext(ctx context.Context) ([]byte, error)
+}
+
+type ContextUnmarshaler interface {
+	UnmarshalJSONContext(ctx context.Context, content []byte) error
+}

common/json/internal/contextjson/context.go

@@ -0,0 +1,11 @@
+package json
+
+import "context"
+
+type ContextMarshaler interface {
+	MarshalJSONContext(ctx context.Context) ([]byte, error)
+}
+
+type ContextUnmarshaler interface {
+	UnmarshalJSONContext(ctx context.Context, content []byte) error
+}

common/json/internal/contextjson/context_test.go

@@ -0,0 +1,43 @@
+package json_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/sagernet/sing/common/json/internal/contextjson"
+
+	"github.com/stretchr/testify/require"
+)
+
+type myStruct struct {
+	value string
+}
+
+func (m *myStruct) MarshalJSONContext(ctx context.Context) ([]byte, error) {
+	return json.Marshal(ctx.Value("key").(string))
+}
+
+func (m *myStruct) UnmarshalJSONContext(ctx context.Context, content []byte) error {
+	m.value = ctx.Value("key").(string)
+	return nil
+}
+
+//nolint:staticcheck
+func TestMarshalContext(t *testing.T) {
+	t.Parallel()
+	ctx := context.WithValue(context.Background(), "key", "value")
+	var s myStruct
+	b, err := json.MarshalContext(ctx, &s)
+	require.NoError(t, err)
+	require.Equal(t, []byte(`"value"`), b)
+}
+
+//nolint:staticcheck
+func TestUnmarshalContext(t *testing.T) {
+	t.Parallel()
+	ctx := context.WithValue(context.Background(), "key", "value")
+	var s myStruct
+	err := json.UnmarshalContext(ctx, []byte(`{}`), &s)
+	require.NoError(t, err)
+	require.Equal(t, "value", s.value)
+}

common/json/internal/contextjson/decode.go

@@ -8,6 +8,7 @@
 package json
 
 import (
+	"context"
 	"encoding"
 	"encoding/base64"
 	"fmt"
@@ -95,10 +96,15 @@ import (
 // Instead, they are replaced by the Unicode replacement
 // character U+FFFD.
 func Unmarshal(data []byte, v any) error {
+	return UnmarshalContext(context.Background(), data, v)
+}
+
+func UnmarshalContext(ctx context.Context, data []byte, v any) error {
 	// Check for well-formedness.
 	// Avoids filling out half a data structure
 	// before discovering a JSON syntax error.
 	var d decodeState
+	d.ctx = ctx
 	err := checkValid(data, &d.scan)
 	if err != nil {
 		return err
@@ -209,6 +215,7 @@ type errorContext struct {
 
 // decodeState represents the state while decoding a JSON value.
 type decodeState struct {
+	ctx                   context.Context
 	data                  []byte
 	off                   int // next read offset in data
 	opcode                int // last read result
@@ -428,7 +435,7 @@ func (d *decodeState) valueQuoted() any {
 // If it encounters an Unmarshaler, indirect stops and returns that.
 // If decodingNull is true, indirect stops at the first settable pointer so it
 // can be set to nil.
-func indirect(v reflect.Value, decodingNull bool) (Unmarshaler, encoding.TextUnmarshaler, reflect.Value) {
+func indirect(v reflect.Value, decodingNull bool) (Unmarshaler, ContextUnmarshaler, encoding.TextUnmarshaler, reflect.Value) {
 	// Issue #24153 indicates that it is generally not a guaranteed property
 	// that you may round-trip a reflect.Value by calling Value.Addr().Elem()
 	// and expect the value to still be settable for values derived from
@@ -482,11 +489,14 @@ func indirect(v reflect.Value, decodingNull bool) (Unmarshaler, encoding.TextUnm
 		}
 		if v.Type().NumMethod() > 0 && v.CanInterface() {
 			if u, ok := v.Interface().(Unmarshaler); ok {
-				return u, nil, reflect.Value{}
+				return u, nil, nil, reflect.Value{}
+			}
+			if cu, ok := v.Interface().(ContextUnmarshaler); ok {
+				return nil, cu, nil, reflect.Value{}
 			}
 			if !decodingNull {
 				if u, ok := v.Interface().(encoding.TextUnmarshaler); ok {
-					return nil, u, reflect.Value{}
+					return nil, nil, u, reflect.Value{}
 				}
 			}
 		}
@@ -498,14 +508,14 @@ func indirect(v reflect.Value, decodingNull bool) (Unmarshaler, encoding.TextUnm
 			v = v.Elem()
 		}
 	}
-	return nil, nil, v
+	return nil, nil, nil, v
 }
 
 // array consumes an array from d.data[d.off-1:], decoding into v.
 // The first byte of the array ('[') has been read already.
 func (d *decodeState) array(v reflect.Value) error {
 	// Check for unmarshaler.
-	u, ut, pv := indirect(v, false)
+	u, cu, ut, pv := indirect(v, false)
 	if u != nil {
 		start := d.readIndex()
 		d.skip()
@@ -515,6 +525,15 @@ func (d *decodeState) array(v reflect.Value) error {
 		}
 		return nil
 	}
+	if cu != nil {
+		start := d.readIndex()
+		d.skip()
+		err := cu.UnmarshalJSONContext(d.ctx, d.data[start:d.off])
+		if err != nil {
+			d.saveError(err)
+		}
+		return nil
+	}
 	if ut != nil {
 		d.saveError(&UnmarshalTypeError{Value: "array", Type: v.Type(), Offset: int64(d.off)})
 		d.skip()
@@ -612,7 +631,7 @@ var (
 // The first byte ('{') of the object has been read already.
 func (d *decodeState) object(v reflect.Value) error {
 	// Check for unmarshaler.
-	u, ut, pv := indirect(v, false)
+	u, cu, ut, pv := indirect(v, false)
 	if u != nil {
 		start := d.readIndex()
 		d.skip()
@@ -622,6 +641,15 @@ func (d *decodeState) object(v reflect.Value) error {
 		}
 		return nil
 	}
+	if cu != nil {
+		start := d.readIndex()
+		d.skip()
+		err := cu.UnmarshalJSONContext(d.ctx, d.data[start:d.off])
+		if err != nil {
+			d.saveError(err)
+		}
+		return nil
+	}
 	if ut != nil {
 		d.saveError(&UnmarshalTypeError{Value: "object", Type: v.Type(), Offset: int64(d.off)})
 		d.skip()
@@ -870,7 +898,7 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 		return nil
 	}
 	isNull := item[0] == 'n' // null
-	u, ut, pv := indirect(v, isNull)
+	u, cu, ut, pv := indirect(v, isNull)
 	if u != nil {
 		err := u.UnmarshalJSON(item)
 		if err != nil {
@@ -878,6 +906,13 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 		}
 		return nil
 	}
+	if cu != nil {
+		err := cu.UnmarshalJSONContext(d.ctx, item)
+		if err != nil {
+			d.saveError(err)
+		}
+		return nil
+	}
 	if ut != nil {
 		if item[0] != '"' {
 			if fromQuoted {

common/json/internal/contextjson/encode.go

@@ -12,6 +12,7 @@ package json
 
 import (
 	"bytes"
+	"context"
 	"encoding"
 	"encoding/base64"
 	"fmt"
@@ -156,7 +157,11 @@ import (
 // handle them. Passing cyclic structures to Marshal will result in
 // an error.
 func Marshal(v any) ([]byte, error) {
-	e := newEncodeState()
+	return MarshalContext(context.Background(), v)
+}
+
+func MarshalContext(ctx context.Context, v any) ([]byte, error) {
+	e := newEncodeState(ctx)
 	defer encodeStatePool.Put(e)
 
 	err := e.marshal(v, encOpts{escapeHTML: true})
@@ -251,6 +256,7 @@ var hex = "0123456789abcdef"
 type encodeState struct {
 	bytes.Buffer // accumulated output
 
+	ctx context.Context
 	// Keep track of what pointers we've seen in the current recursive call
 	// path, to avoid cycles that could lead to a stack overflow. Only do
 	// the relatively expensive map operations if ptrLevel is larger than
@@ -264,7 +270,7 @@ const startDetectingCyclesAfter = 1000
 
 var encodeStatePool sync.Pool
 
-func newEncodeState() *encodeState {
+func newEncodeState(ctx context.Context) *encodeState {
 	if v := encodeStatePool.Get(); v != nil {
 		e := v.(*encodeState)
 		e.Reset()
@@ -274,7 +280,7 @@ func newEncodeState() *encodeState {
 		e.ptrLevel = 0
 		return e
 	}
-	return &encodeState{ptrSeen: make(map[any]struct{})}
+	return &encodeState{ctx: ctx, ptrSeen: make(map[any]struct{})}
 }
 
 // jsonError is an error wrapper type for internal use only.
@@ -371,8 +377,9 @@ func typeEncoder(t reflect.Type) encoderFunc {
 }
 
 var (
-	marshalerType     = reflect.TypeOf((*Marshaler)(nil)).Elem()
-	textMarshalerType = reflect.TypeOf((*encoding.TextMarshaler)(nil)).Elem()
+	marshalerType        = reflect.TypeOf((*Marshaler)(nil)).Elem()
+	contextMarshalerType = reflect.TypeOf((*ContextMarshaler)(nil)).Elem()
+	textMarshalerType    = reflect.TypeOf((*encoding.TextMarshaler)(nil)).Elem()
 )
 
 // newTypeEncoder constructs an encoderFunc for a type.
@@ -385,9 +392,15 @@ func newTypeEncoder(t reflect.Type, allowAddr bool) encoderFunc {
 	if t.Kind() != reflect.Pointer && allowAddr && reflect.PointerTo(t).Implements(marshalerType) {
 		return newCondAddrEncoder(addrMarshalerEncoder, newTypeEncoder(t, false))
 	}
+	if t.Kind() != reflect.Pointer && allowAddr && reflect.PointerTo(t).Implements(contextMarshalerType) {
+		return newCondAddrEncoder(addrContextMarshalerEncoder, newTypeEncoder(t, false))
+	}
 	if t.Implements(marshalerType) {
 		return marshalerEncoder
 	}
+	if t.Implements(contextMarshalerType) {
+		return contextMarshalerEncoder
+	}
 	if t.Kind() != reflect.Pointer && allowAddr && reflect.PointerTo(t).Implements(textMarshalerType) {
 		return newCondAddrEncoder(addrTextMarshalerEncoder, newTypeEncoder(t, false))
 	}
@@ -470,6 +483,47 @@ func addrMarshalerEncoder(e *encodeState, v reflect.Value, opts encOpts) {
 	}
 }
 
+func contextMarshalerEncoder(e *encodeState, v reflect.Value, opts encOpts) {
+	if v.Kind() == reflect.Pointer && v.IsNil() {
+		e.WriteString("null")
+		return
+	}
+	m, ok := v.Interface().(ContextMarshaler)
+	if !ok {
+		e.WriteString("null")
+		return
+	}
+	b, err := m.MarshalJSONContext(e.ctx)
+	if err == nil {
+		e.Grow(len(b))
+		out := availableBuffer(&e.Buffer)
+		out, err = appendCompact(out, b, opts.escapeHTML)
+		e.Buffer.Write(out)
+	}
+	if err != nil {
+		e.error(&MarshalerError{v.Type(), err, "MarshalJSON"})
+	}
+}
+
+func addrContextMarshalerEncoder(e *encodeState, v reflect.Value, opts encOpts) {
+	va := v.Addr()
+	if va.IsNil() {
+		e.WriteString("null")
+		return
+	}
+	m := va.Interface().(ContextMarshaler)
+	b, err := m.MarshalJSONContext(e.ctx)
+	if err == nil {
+		e.Grow(len(b))
+		out := availableBuffer(&e.Buffer)
+		out, err = appendCompact(out, b, opts.escapeHTML)
+		e.Buffer.Write(out)
+	}
+	if err != nil {
+		e.error(&MarshalerError{v.Type(), err, "MarshalJSON"})
+	}
+}
+
 func textMarshalerEncoder(e *encodeState, v reflect.Value, opts encOpts) {
 	if v.Kind() == reflect.Pointer && v.IsNil() {
 		e.WriteString("null")
@@ -827,7 +881,7 @@ func newSliceEncoder(t reflect.Type) encoderFunc {
 	// Byte slices get special treatment; arrays don't.
 	if t.Elem().Kind() == reflect.Uint8 {
 		p := reflect.PointerTo(t.Elem())
-		if !p.Implements(marshalerType) && !p.Implements(textMarshalerType) {
+		if !p.Implements(marshalerType) && !p.Implements(contextMarshalerType) && !p.Implements(textMarshalerType) {
 			return encodeByteSlice
 		}
 	}

common/json/internal/contextjson/keys.go

@@ -0,0 +1,20 @@
+package json
+
+import (
+	"reflect"
+
+	"github.com/sagernet/sing/common"
+)
+
+func ObjectKeys(object reflect.Type) []string {
+	switch object.Kind() {
+	case reflect.Pointer:
+		return ObjectKeys(object.Elem())
+	case reflect.Struct:
+	default:
+		panic("invalid non-struct input")
+	}
+	return common.Map(cachedTypeFields(object).list, func(field field) string {
+		return field.name
+	})
+}

common/json/internal/contextjson/keys_test.go

@@ -0,0 +1,26 @@
+package json_test
+
+import (
+	"reflect"
+	"testing"
+
+	json "github.com/sagernet/sing/common/json/internal/contextjson"
+
+	"github.com/stretchr/testify/require"
+)
+
+type MyObject struct {
+	Hello string `json:"hello,omitempty"`
+	MyWorld
+	MyWorld2 string `json:"-"`
+}
+
+type MyWorld struct {
+	World string `json:"world,omitempty"`
+}
+
+func TestObjectKeys(t *testing.T) {
+	t.Parallel()
+	keys := json.ObjectKeys(reflect.TypeOf(&MyObject{}))
+	require.Equal(t, []string{"hello", "world"}, keys)
+}

common/json/internal/contextjson/stream.go

@@ -6,6 +6,7 @@ package json
 
 import (
 	"bytes"
+	"context"
 	"errors"
 	"io"
 )
@@ -29,7 +30,11 @@ type Decoder struct {
 // The decoder introduces its own buffering and may
 // read data from r beyond the JSON values requested.
 func NewDecoder(r io.Reader) *Decoder {
-	return &Decoder{r: r}
+	return NewDecoderContext(context.Background(), r)
+}
+
+func NewDecoderContext(ctx context.Context, r io.Reader) *Decoder {
+	return &Decoder{r: r, d: decodeState{ctx: ctx}}
 }
 
 // UseNumber causes the Decoder to unmarshal a number into an interface{} as a
@@ -183,6 +188,7 @@ func nonSpace(b []byte) bool {
 
 // An Encoder writes JSON values to an output stream.
 type Encoder struct {
+	ctx        context.Context
 	w          io.Writer
 	err        error
 	escapeHTML bool
@@ -194,7 +200,11 @@ type Encoder struct {
 
 // NewEncoder returns a new encoder that writes to w.
 func NewEncoder(w io.Writer) *Encoder {
-	return &Encoder{w: w, escapeHTML: true}
+	return NewEncoderContext(context.Background(), w)
+}
+
+func NewEncoderContext(ctx context.Context, w io.Writer) *Encoder {
+	return &Encoder{ctx: ctx, w: w, escapeHTML: true}
 }
 
 // Encode writes the JSON encoding of v to the stream,
@@ -207,7 +217,7 @@ func (enc *Encoder) Encode(v any) error {
 		return enc.err
 	}
 
-	e := newEncodeState()
+	e := newEncodeState(enc.ctx)
 	defer encodeStatePool.Put(e)
 
 	err := e.marshal(v, encOpts{escapeHTML: enc.escapeHTML})

common/json/internal/contextjson/unmarshal.go

@@ -1,5 +1,7 @@
 package json
 
+import "context"
+
 func UnmarshalDisallowUnknownFields(data []byte, v any) error {
 	var d decodeState
 	d.disallowUnknownFields = true
@@ -10,3 +12,15 @@ func UnmarshalDisallowUnknownFields(data []byte, v any) error {
 	d.init(data)
 	return d.unmarshal(v)
 }
+
+func UnmarshalContextDisallowUnknownFields(ctx context.Context, data []byte, v any) error {
+	var d decodeState
+	d.ctx = ctx
+	d.disallowUnknownFields = true
+	err := checkValid(data, &d.scan)
+	if err != nil {
+		return err
+	}
+	d.init(data)
+	return d.unmarshal(v)
+}

common/json/unmarshal.go

@@ -2,6 +2,7 @@ package json
 
 import (
 	"bytes"
+	"context"
 	"errors"
 	"strings"
 
@@ -10,7 +11,11 @@ import (
 )
 
 func UnmarshalExtended[T any](content []byte) (T, error) {
-	decoder := NewDecoder(NewCommentFilter(bytes.NewReader(content)))
+	return UnmarshalExtendedContext[T](context.Background(), content)
+}
+
+func UnmarshalExtendedContext[T any](ctx context.Context, content []byte) (T, error) {
+	decoder := NewDecoderContext(ctx, NewCommentFilter(bytes.NewReader(content)))
 	var value T
 	err := decoder.Decode(&value)
 	if err == nil {

common/metadata/metadata.go

@@ -1,5 +1,6 @@
 package metadata
 
+// Deprecated: wtf is this?
 type Metadata struct {
 	Protocol    string
 	Source      Socksaddr

common/minmax.go

@@ -0,0 +1,15 @@
+//go:build go1.21
+
+package common
+
+import (
+	"cmp"
+)
+
+func Min[T cmp.Ordered](x, y T) T {
+	return min(x, y)
+}
+
+func Max[T cmp.Ordered](x, y T) T {
+	return max(x, y)
+}

common/minmax_compat.go

@@ -0,0 +1,19 @@
+//go:build go1.20 && !go1.21
+
+package common
+
+import "github.com/sagernet/sing/common/x/constraints"
+
+func Min[T constraints.Ordered](x, y T) T {
+	if x < y {
+		return x
+	}
+	return y
+}
+
+func Max[T constraints.Ordered](x, y T) T {
+	if x < y {
+		return y
+	}
+	return x
+}

common/network/conn.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"io"
 	"net"
+	"sync"
 	"time"
 
 	"github.com/sagernet/sing/common"
@@ -70,8 +71,39 @@ type ExtendedConn interface {
 	net.Conn
 }
 
+type CloseHandlerFunc = func(it error)
+
+func AppendClose(parent CloseHandlerFunc, onClose CloseHandlerFunc) CloseHandlerFunc {
+	if onClose == nil {
+		panic("nil onClose")
+	}
+	if parent == nil {
+		return onClose
+	}
+	return func(it error) {
+		onClose(it)
+		parent(it)
+	}
+}
+
+func OnceClose(onClose CloseHandlerFunc) CloseHandlerFunc {
+	var once sync.Once
+	return func(it error) {
+		once.Do(func() {
+			onClose(it)
+		})
+	}
+}
+
+// Deprecated: Use TCPConnectionHandlerEx instead.
 type TCPConnectionHandler interface {
-	NewConnection(ctx context.Context, conn net.Conn, metadata M.Metadata) error
+	NewConnection(ctx context.Context, conn net.Conn,
+		//nolint:staticcheck
+		metadata M.Metadata) error
+}
+
+type TCPConnectionHandlerEx interface {
+	NewConnectionEx(ctx context.Context, conn net.Conn, source M.Socksaddr, destination M.Socksaddr, onClose CloseHandlerFunc)
 }
 
 type NetPacketConn interface {
@@ -85,12 +117,26 @@ type BindPacketConn interface {
 	net.Conn
 }
 
+// Deprecated: Use UDPHandlerEx instead.
 type UDPHandler interface {
-	NewPacket(ctx context.Context, conn PacketConn, buffer *buf.Buffer, metadata M.Metadata) error
+	NewPacket(ctx context.Context, conn PacketConn, buffer *buf.Buffer,
+		//nolint:staticcheck
+		metadata M.Metadata) error
 }
 
+type UDPHandlerEx interface {
+	NewPacketEx(buffer *buf.Buffer, source M.Socksaddr)
+}
+
+// Deprecated: Use UDPConnectionHandlerEx instead.
 type UDPConnectionHandler interface {
-	NewPacketConnection(ctx context.Context, conn PacketConn, metadata M.Metadata) error
+	NewPacketConnection(ctx context.Context, conn PacketConn,
+		//nolint:staticcheck
+		metadata M.Metadata) error
+}
+
+type UDPConnectionHandlerEx interface {
+	NewPacketConnectionEx(ctx context.Context, conn PacketConn, source M.Socksaddr, destination M.Socksaddr, onClose CloseHandlerFunc)
 }
 
 type CachedReader interface {
@@ -101,11 +147,6 @@ type CachedPacketReader interface {
 	ReadCachedPacket() *PacketBuffer
 }
 
-type PacketBuffer struct {
-	Buffer      *buf.Buffer
-	Destination M.Socksaddr
-}
-
 type WithUpstreamReader interface {
 	UpstreamReader() any
 }

common/network/dialer.go

@@ -13,10 +13,6 @@ type Dialer interface {
 	ListenPacket(ctx context.Context, destination M.Socksaddr) (net.PacketConn, error)
 }
 
-type PayloadDialer interface {
-	DialPayloadContext(ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error)
-}
-
 type ParallelDialer interface {
 	Dialer
 	DialParallel(ctx context.Context, network string, destination M.Socksaddr, destinationAddresses []netip.Addr) (net.Conn, error)

common/network/direct.go

@@ -15,19 +15,39 @@ type ReadWaitOptions struct {
 	MTU           int
 }
 
+func NewReadWaitOptions(source any, destination any) ReadWaitOptions {
+	return ReadWaitOptions{
+		FrontHeadroom: CalculateFrontHeadroom(destination),
+		RearHeadroom:  CalculateRearHeadroom(destination),
+		MTU:           CalculateMTU(source, destination),
+	}
+}
+
 func (o ReadWaitOptions) NeedHeadroom() bool {
 	return o.FrontHeadroom > 0 || o.RearHeadroom > 0
 }
 
+func (o ReadWaitOptions) Copy(buffer *buf.Buffer) *buf.Buffer {
+	if o.FrontHeadroom > buffer.Start() ||
+		o.RearHeadroom > buffer.FreeLen() {
+		newBuffer := o.newBuffer(buf.UDPBufferSize, false)
+		newBuffer.Write(buffer.Bytes())
+		buffer.Release()
+		return newBuffer
+	} else {
+		return buffer
+	}
+}
+
 func (o ReadWaitOptions) NewBuffer() *buf.Buffer {
-	return o.newBuffer(buf.BufferSize)
+	return o.newBuffer(buf.BufferSize, true)
 }
 
 func (o ReadWaitOptions) NewPacketBuffer() *buf.Buffer {
-	return o.newBuffer(buf.UDPBufferSize)
+	return o.newBuffer(buf.UDPBufferSize, true)
 }
 
-func (o ReadWaitOptions) newBuffer(defaultBufferSize int) *buf.Buffer {
+func (o ReadWaitOptions) newBuffer(defaultBufferSize int, reserve bool) *buf.Buffer {
 	var bufferSize int
 	if o.MTU > 0 {
 		bufferSize = o.MTU + o.FrontHeadroom + o.RearHeadroom
@@ -38,7 +58,7 @@ func (o ReadWaitOptions) newBuffer(defaultBufferSize int) *buf.Buffer {
 	if o.FrontHeadroom > 0 {
 		buffer.Resize(o.FrontHeadroom, 0)
 	}
-	if o.RearHeadroom > 0 {
+	if o.RearHeadroom > 0 && reserve {
 		buffer.Reserve(o.RearHeadroom)
 	}
 	return buffer

common/network/handshake.go

@@ -1,6 +1,9 @@
 package network
 
 import (
+	"io"
+	"net"
+
 	"github.com/sagernet/sing/common"
 	E "github.com/sagernet/sing/common/exceptions"
 )
@@ -13,17 +16,75 @@ type HandshakeSuccess interface {
 	HandshakeSuccess() error
 }
 
-func ReportHandshakeFailure(conn any, err error) error {
-	if handshakeConn, isHandshakeConn := common.Cast[HandshakeFailure](conn); isHandshakeConn {
+type ConnHandshakeSuccess interface {
+	ConnHandshakeSuccess(conn net.Conn) error
+}
+
+type PacketConnHandshakeSuccess interface {
+	PacketConnHandshakeSuccess(conn net.PacketConn) error
+}
+
+func ReportHandshakeFailure(reporter any, err error) error {
+	if handshakeConn, isHandshakeConn := common.Cast[HandshakeFailure](reporter); isHandshakeConn {
 		return E.Append(err, handshakeConn.HandshakeFailure(err), func(err error) error {
 			return E.Cause(err, "write handshake failure")
 		})
 	}
+	return nil
+}
+
+func CloseOnHandshakeFailure(reporter io.Closer, onClose CloseHandlerFunc, err error) error {
+	if err != nil {
+		if handshakeConn, isHandshakeConn := common.Cast[HandshakeFailure](reporter); isHandshakeConn {
+			hErr := handshakeConn.HandshakeFailure(err)
+			err = E.Append(err, hErr, func(err error) error {
+				if closer, isCloser := reporter.(io.Closer); isCloser {
+					err = E.Append(err, closer.Close(), func(err error) error {
+						return E.Cause(err, "close")
+					})
+				}
+				return E.Cause(err, "write handshake failure")
+			})
+		} else {
+			if tcpConn, isTCPConn := common.Cast[interface {
+				SetLinger(sec int) error
+			}](reporter); isTCPConn {
+				tcpConn.SetLinger(0)
+			}
+		}
+		err = E.Append(err, reporter.Close(), func(err error) error {
+			return E.Cause(err, "close")
+		})
+	}
+	if onClose != nil {
+		onClose(err)
+	}
 	return err
 }
 
-func ReportHandshakeSuccess(conn any) error {
-	if handshakeConn, isHandshakeConn := common.Cast[HandshakeSuccess](conn); isHandshakeConn {
+// Deprecated: use ReportConnHandshakeSuccess/ReportPacketConnHandshakeSuccess instead
+func ReportHandshakeSuccess(reporter any) error {
+	if handshakeConn, isHandshakeConn := common.Cast[HandshakeSuccess](reporter); isHandshakeConn {
+		return handshakeConn.HandshakeSuccess()
+	}
+	return nil
+}
+
+func ReportConnHandshakeSuccess(reporter any, conn net.Conn) error {
+	if handshakeConn, isHandshakeConn := common.Cast[ConnHandshakeSuccess](reporter); isHandshakeConn {
+		return handshakeConn.ConnHandshakeSuccess(conn)
+	}
+	if handshakeConn, isHandshakeConn := common.Cast[HandshakeSuccess](reporter); isHandshakeConn {
+		return handshakeConn.HandshakeSuccess()
+	}
+	return nil
+}
+
+func ReportPacketConnHandshakeSuccess(reporter any, conn net.PacketConn) error {
+	if handshakeConn, isHandshakeConn := common.Cast[PacketConnHandshakeSuccess](reporter); isHandshakeConn {
+		return handshakeConn.PacketConnHandshakeSuccess(conn)
+	}
+	if handshakeConn, isHandshakeConn := common.Cast[HandshakeSuccess](reporter); isHandshakeConn {
 		return handshakeConn.HandshakeSuccess()
 	}
 	return nil

common/network/packet.go

@@ -0,0 +1,35 @@
+package network
+
+import (
+	"sync"
+
+	"github.com/sagernet/sing/common/buf"
+	M "github.com/sagernet/sing/common/metadata"
+)
+
+type PacketBuffer struct {
+	Buffer      *buf.Buffer
+	Destination M.Socksaddr
+}
+
+var packetPool = sync.Pool{
+	New: func() any {
+		return new(PacketBuffer)
+	},
+}
+
+func NewPacketBuffer() *PacketBuffer {
+	return packetPool.Get().(*PacketBuffer)
+}
+
+func PutPacketBuffer(packet *PacketBuffer) {
+	*packet = PacketBuffer{}
+	packetPool.Put(packet)
+}
+
+func ReleaseMultiPacketBuffer(packetBuffers []*PacketBuffer) {
+	for _, packet := range packetBuffers {
+		packet.Buffer.Release()
+		PutPacketBuffer(packet)
+	}
+}

common/network/thread.go

@@ -11,6 +11,7 @@ type ThreadUnsafeWriter interface {
 }
 
 // Deprecated: Use ReadWaiter interface instead.
+
 type ThreadSafeReader interface {
 	// Deprecated: Use ReadWaiter interface instead.
 	ReadBufferThreadSafe() (buffer *buf.Buffer, err error)
@@ -18,7 +19,6 @@ type ThreadSafeReader interface {
 
 // Deprecated: Use ReadWaiter interface instead.
 type ThreadSafePacketReader interface {
-	// Deprecated: Use ReadWaiter interface instead.
 	ReadPacketThreadSafe() (buffer *buf.Buffer, addr M.Socksaddr, err error)
 }
 

common/ntp/service.go

@@ -141,7 +141,7 @@ func (s *Service) update() error {
 	if s.timeout > 0 {
 		ctx, cancel = context.WithTimeout(ctx, s.timeout)
 	}
-	response, err := Exchange(s.ctx, s.dialer, s.server)
+	response, err := Exchange(ctx, s.dialer, s.server)
 	if cancel != nil {
 		cancel()
 	}

common/ntp/syscall_windows.go

@@ -0,0 +1,6 @@
+package ntp
+
+//go:generate go run golang.org/x/sys/windows/mkwinsyscall -output zsyscall_windows.go syscall_windows.go
+
+// https://learn.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-setsystemtime
+//sys setSystemTime(lpSystemTime *windows.Systemtime) (err error) = kernel32.SetSystemTime

common/ntp/time_windows.go

@@ -2,12 +2,12 @@ package ntp
 
 import (
 	"time"
-	"unsafe"
 
 	"golang.org/x/sys/windows"
 )
 
 func SetSystemTime(nowTime time.Time) error {
+	nowTime = nowTime.UTC()
 	var systemTime windows.Systemtime
 	systemTime.Year = uint16(nowTime.Year())
 	systemTime.Month = uint16(nowTime.Month())
@@ -16,17 +16,5 @@ func SetSystemTime(nowTime time.Time) error {
 	systemTime.Minute = uint16(nowTime.Minute())
 	systemTime.Second = uint16(nowTime.Second())
 	systemTime.Milliseconds = uint16(nowTime.UnixMilli() - nowTime.Unix()*1000)
-
-	dllKernel32 := windows.NewLazySystemDLL("kernel32.dll")
-	proc := dllKernel32.NewProc("SetSystemTime")
-
-	_, _, err := proc.Call(
-		uintptr(unsafe.Pointer(&systemTime)),
-	)
-
-	if err != nil && err.Error() != "The operation completed successfully." {
-		return err
-	}
-
-	return nil
+	return setSystemTime(&systemTime)
 }

common/ntp/zsyscall_windows.go

@@ -0,0 +1,52 @@
+// Code generated by 'go generate'; DO NOT EDIT.
+
+package ntp
+
+import (
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+var _ unsafe.Pointer
+
+// Do the interface allocations only once for common
+// Errno values.
+const (
+	errnoERROR_IO_PENDING = 997
+)
+
+var (
+	errERROR_IO_PENDING error = syscall.Errno(errnoERROR_IO_PENDING)
+	errERROR_EINVAL     error = syscall.EINVAL
+)
+
+// errnoErr returns common boxed Errno values, to prevent
+// allocations at runtime.
+func errnoErr(e syscall.Errno) error {
+	switch e {
+	case 0:
+		return errERROR_EINVAL
+	case errnoERROR_IO_PENDING:
+		return errERROR_IO_PENDING
+	}
+	// TODO: add more here, after collecting data on the common
+	// error values see on Windows. (perhaps when running
+	// all.bat?)
+	return e
+}
+
+var (
+	modkernel32 = windows.NewLazySystemDLL("kernel32.dll")
+
+	procSetSystemTime = modkernel32.NewProc("SetSystemTime")
+)
+
+func setSystemTime(lpSystemTime *windows.Systemtime) (err error) {
+	r1, _, e1 := syscall.Syscall(procSetSystemTime.Addr(), 1, uintptr(unsafe.Pointer(lpSystemTime)), 0, 0)
+	if r1 == 0 {
+		err = errnoErr(e1)
+	}
+	return
+}

common/oncefunc.go

@@ -0,0 +1,20 @@
+//go:build go1.21
+
+package common
+
+import "sync"
+
+// OnceFunc is a wrapper around sync.OnceFunc.
+func OnceFunc(f func()) func() {
+	return sync.OnceFunc(f)
+}
+
+// OnceValue is a wrapper around sync.OnceValue.
+func OnceValue[T any](f func() T) func() T {
+	return sync.OnceValue(f)
+}
+
+// OnceValues is a wrapper around sync.OnceValues.
+func OnceValues[T1, T2 any](f func() (T1, T2)) func() (T1, T2) {
+	return sync.OnceValues(f)
+}

common/oncefunc_compat.go

@@ -0,0 +1,104 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.20 && !go1.21
+
+package common
+
+import "sync"
+
+// OnceFunc returns a function that invokes f only once. The returned function
+// may be called concurrently.
+//
+// If f panics, the returned function will panic with the same value on every call.
+func OnceFunc(f func()) func() {
+	var (
+		once  sync.Once
+		valid bool
+		p     any
+	)
+	// Construct the inner closure just once to reduce costs on the fast path.
+	g := func() {
+		defer func() {
+			p = recover()
+			if !valid {
+				// Re-panic immediately so on the first call the user gets a
+				// complete stack trace into f.
+				panic(p)
+			}
+		}()
+		f()
+		f = nil      // Do not keep f alive after invoking it.
+		valid = true // Set only if f does not panic.
+	}
+	return func() {
+		once.Do(g)
+		if !valid {
+			panic(p)
+		}
+	}
+}
+
+// OnceValue returns a function that invokes f only once and returns the value
+// returned by f. The returned function may be called concurrently.
+//
+// If f panics, the returned function will panic with the same value on every call.
+func OnceValue[T any](f func() T) func() T {
+	var (
+		once   sync.Once
+		valid  bool
+		p      any
+		result T
+	)
+	g := func() {
+		defer func() {
+			p = recover()
+			if !valid {
+				panic(p)
+			}
+		}()
+		result = f()
+		f = nil
+		valid = true
+	}
+	return func() T {
+		once.Do(g)
+		if !valid {
+			panic(p)
+		}
+		return result
+	}
+}
+
+// OnceValues returns a function that invokes f only once and returns the values
+// returned by f. The returned function may be called concurrently.
+//
+// If f panics, the returned function will panic with the same value on every call.
+func OnceValues[T1, T2 any](f func() (T1, T2)) func() (T1, T2) {
+	var (
+		once  sync.Once
+		valid bool
+		p     any
+		r1    T1
+		r2    T2
+	)
+	g := func() {
+		defer func() {
+			p = recover()
+			if !valid {
+				panic(p)
+			}
+		}()
+		r1, r2 = f()
+		f = nil
+		valid = true
+	}
+	return func() (T1, T2) {
+		once.Do(g)
+		if !valid {
+			panic(p)
+		}
+		return r1, r2
+	}
+}

common/pipe/pipe.go

@@ -14,24 +14,24 @@ import (
 	N "github.com/sagernet/sing/common/network"
 )
 
-// pipeDeadline is an abstraction for handling timeouts.
-type pipeDeadline struct {
+// Deadline is an abstraction for handling timeouts.
+type Deadline struct {
 	mu     sync.Mutex // Guards timer and cancel
 	timer  *time.Timer
 	cancel chan struct{} // Must be non-nil
 }
 
-func makePipeDeadline() pipeDeadline {
-	return pipeDeadline{cancel: make(chan struct{})}
+func MakeDeadline() Deadline {
+	return Deadline{cancel: make(chan struct{})}
 }
 
-// set sets the point in time when the deadline will time out.
+// Set sets the point in time when the deadline will time out.
 // A timeout event is signaled by closing the channel returned by waiter.
 // Once a timeout has occurred, the deadline can be refreshed by specifying a
 // t value in the future.
 //
 // A zero value for t prevents timeout.
-func (d *pipeDeadline) set(t time.Time) {
+func (d *Deadline) Set(t time.Time) {
 	d.mu.Lock()
 	defer d.mu.Unlock()
 
@@ -66,8 +66,8 @@ func (d *pipeDeadline) set(t time.Time) {
 	}
 }
 
-// wait returns a channel that is closed when the deadline is exceeded.
-func (d *pipeDeadline) wait() chan struct{} {
+// Wait returns a channel that is closed when the deadline is exceeded.
+func (d *Deadline) Wait() chan struct{} {
 	d.mu.Lock()
 	defer d.mu.Unlock()
 	return d.cancel
@@ -104,8 +104,8 @@ type pipe struct {
 	localDone  chan struct{}
 	remoteDone <-chan struct{}
 
-	readDeadline  pipeDeadline
-	writeDeadline pipeDeadline
+	readDeadline  Deadline
+	writeDeadline Deadline
 
 	readWaitOptions N.ReadWaitOptions
 }
@@ -127,15 +127,15 @@ func Pipe() (net.Conn, net.Conn) {
 		rdRx: cb1, rdTx: cn1,
 		wrTx: cb2, wrRx: cn2,
 		localDone: done1, remoteDone: done2,
-		readDeadline:  makePipeDeadline(),
-		writeDeadline: makePipeDeadline(),
+		readDeadline:  MakeDeadline(),
+		writeDeadline: MakeDeadline(),
 	}
 	p2 := &pipe{
 		rdRx: cb2, rdTx: cn2,
 		wrTx: cb1, wrRx: cn1,
 		localDone: done2, remoteDone: done1,
-		readDeadline:  makePipeDeadline(),
-		writeDeadline: makePipeDeadline(),
+		readDeadline:  MakeDeadline(),
+		writeDeadline: MakeDeadline(),
 	}
 	return p1, p2
 }
@@ -157,7 +157,7 @@ func (p *pipe) read(b []byte) (n int, err error) {
 		return 0, io.ErrClosedPipe
 	case isClosedChan(p.remoteDone):
 		return 0, io.EOF
-	case isClosedChan(p.readDeadline.wait()):
+	case isClosedChan(p.readDeadline.Wait()):
 		return 0, os.ErrDeadlineExceeded
 	}
 
@@ -170,7 +170,7 @@ func (p *pipe) read(b []byte) (n int, err error) {
 		return 0, io.ErrClosedPipe
 	case <-p.remoteDone:
 		return 0, io.EOF
-	case <-p.readDeadline.wait():
+	case <-p.readDeadline.Wait():
 		return 0, os.ErrDeadlineExceeded
 	}
 }
@@ -189,7 +189,7 @@ func (p *pipe) write(b []byte) (n int, err error) {
 		return 0, io.ErrClosedPipe
 	case isClosedChan(p.remoteDone):
 		return 0, io.ErrClosedPipe
-	case isClosedChan(p.writeDeadline.wait()):
+	case isClosedChan(p.writeDeadline.Wait()):
 		return 0, os.ErrDeadlineExceeded
 	}
 
@@ -205,7 +205,7 @@ func (p *pipe) write(b []byte) (n int, err error) {
 			return n, io.ErrClosedPipe
 		case <-p.remoteDone:
 			return n, io.ErrClosedPipe
-		case <-p.writeDeadline.wait():
+		case <-p.writeDeadline.Wait():
 			return n, os.ErrDeadlineExceeded
 		}
 	}
@@ -216,8 +216,8 @@ func (p *pipe) SetDeadline(t time.Time) error {
 	if isClosedChan(p.localDone) || isClosedChan(p.remoteDone) {
 		return io.ErrClosedPipe
 	}
-	p.readDeadline.set(t)
-	p.writeDeadline.set(t)
+	p.readDeadline.Set(t)
+	p.writeDeadline.Set(t)
 	return nil
 }
 
@@ -225,7 +225,7 @@ func (p *pipe) SetReadDeadline(t time.Time) error {
 	if isClosedChan(p.localDone) || isClosedChan(p.remoteDone) {
 		return io.ErrClosedPipe
 	}
-	p.readDeadline.set(t)
+	p.readDeadline.Set(t)
 	return nil
 }
 
@@ -233,7 +233,7 @@ func (p *pipe) SetWriteDeadline(t time.Time) error {
 	if isClosedChan(p.localDone) || isClosedChan(p.remoteDone) {
 		return io.ErrClosedPipe
 	}
-	p.writeDeadline.set(t)
+	p.writeDeadline.Set(t)
 	return nil
 }
 

common/pipe/pipe_wait.go

@@ -30,7 +30,7 @@ func (p *pipe) waitReadBuffer() (buffer *buf.Buffer, err error) {
 		return nil, io.ErrClosedPipe
 	case isClosedChan(p.remoteDone):
 		return nil, io.EOF
-	case isClosedChan(p.readDeadline.wait()):
+	case isClosedChan(p.readDeadline.Wait()):
 		return nil, os.ErrDeadlineExceeded
 	}
 	select {
@@ -49,7 +49,7 @@ func (p *pipe) waitReadBuffer() (buffer *buf.Buffer, err error) {
 		return nil, io.ErrClosedPipe
 	case <-p.remoteDone:
 		return nil, io.EOF
-	case <-p.readDeadline.wait():
+	case <-p.readDeadline.Wait():
 		return nil, os.ErrDeadlineExceeded
 	}
 }

common/random/seed_go119.go

@@ -20,6 +20,5 @@ func InitializeSeed() {
 func initializeSeed() {
 	var seed int64
 	common.Must(binary.Read(rand.Reader, binary.LittleEndian, &seed))
-	//goland:noinspection GoDeprecation
 	mRand.Seed(seed)
 }

common/ranges/range_test.go

@@ -6,6 +6,7 @@ import (
 )
 
 func TestRevertRanges(t *testing.T) {
+	t.Parallel()
 	for _, testRange := range []struct {
 		start, end int
 		ranges     []Range[int]
@@ -77,6 +78,7 @@ func TestRevertRanges(t *testing.T) {
 }
 
 func TestMergeRanges(t *testing.T) {
+	t.Parallel()
 	for _, testRange := range []struct {
 		ranges   []Range[int]
 		expected []Range[int]
@@ -144,6 +146,7 @@ func TestMergeRanges(t *testing.T) {
 }
 
 func TestExcludeRanges(t *testing.T) {
+	t.Parallel()
 	for _, testRange := range []struct {
 		ranges   []Range[int]
 		exclude  []Range[int]

common/rw/varint.go

@@ -27,7 +27,6 @@ func ToByteReader(reader io.Reader) io.ByteReader {
 
 // Deprecated: Use binary.ReadUvarint instead.
 func ReadUVariant(reader io.Reader) (uint64, error) {
-	//goland:noinspection GoDeprecation
 	return binary.ReadUvarint(ToByteReader(reader))
 }
 

common/task/task.go

@@ -54,17 +54,9 @@ func (g *Group) Concurrency(n int) {
 	}
 }
 
-func (g *Group) Run(contextList ...context.Context) error {
-	return g.RunContextList(contextList)
-}
-
-func (g *Group) RunContextList(contextList []context.Context) error {
-	if len(contextList) == 0 {
-		contextList = append(contextList, context.Background())
-	}
-
+func (g *Group) Run(ctx context.Context) error {
 	taskContext, taskFinish := common.ContextWithCancelCause(context.Background())
-	taskCancelContext, taskCancel := common.ContextWithCancelCause(contextList[0])
+	taskCancelContext, taskCancel := common.ContextWithCancelCause(ctx)
 
 	var errorAccess sync.Mutex
 	var returnError error
@@ -112,8 +104,13 @@ func (g *Group) RunContextList(contextList []context.Context) error {
 		}()
 	}
 
-	selectedContext, upstreamErr := common.SelectContext(append([]context.Context{taskCancelContext}, contextList[1:]...))
-	taskCancel(upstreamErr)
+	var upstreamErr bool
+	select {
+	case <-taskCancelContext.Done():
+	case <-ctx.Done():
+		upstreamErr = true
+		taskCancel(ctx.Err())
+	}
 
 	if g.cleanup != nil {
 		g.cleanup()
@@ -121,10 +118,8 @@ func (g *Group) RunContextList(contextList []context.Context) error {
 
 	<-taskContext.Done()
 
-	if selectedContext != 0 {
-		returnError = E.Append(returnError, upstreamErr, func(err error) error {
-			return E.Cause(err, "upstream")
-		})
+	if upstreamErr {
+		return ctx.Err()
 	}
 
 	return returnError

common/task/task_deprecated.go

@@ -2,6 +2,7 @@ package task
 
 import "context"
 
+// Deprecated: Use Group instead
 func Run(ctx context.Context, tasks ...func() error) error {
 	var group Group
 	for _, task := range tasks {
@@ -13,6 +14,7 @@ func Run(ctx context.Context, tasks ...func() error) error {
 	return group.Run(ctx)
 }
 
+// Deprecated: Use Group instead
 func Any(ctx context.Context, tasks ...func(ctx context.Context) error) error {
 	var group Group
 	for _, task := range tasks {

common/udpnat/conn_wait.go

@@ -2,6 +2,7 @@ package udpnat
 
 import (
 	"io"
+	"os"
 
 	"github.com/sagernet/sing/common/buf"
 	M "github.com/sagernet/sing/common/metadata"
@@ -34,5 +35,7 @@ func (c *conn) WaitReadPacket() (buffer *buf.Buffer, destination M.Socksaddr, er
 		return
 	case <-c.ctx.Done():
 		return nil, M.Socksaddr{}, io.ErrClosedPipe
+	case <-c.readDeadline.Wait():
+		return nil, M.Socksaddr{}, os.ErrDeadlineExceeded
 	}
 }

common/udpnat/service.go

@@ -13,20 +13,26 @@ import (
 	E "github.com/sagernet/sing/common/exceptions"
 	M "github.com/sagernet/sing/common/metadata"
 	N "github.com/sagernet/sing/common/network"
+	"github.com/sagernet/sing/common/pipe"
 )
 
+// Deprecated: Use N.UDPConnectionHandler instead.
+//
+//nolint:staticcheck
 type Handler interface {
 	N.UDPConnectionHandler
 	E.Handler
 }
 
 type Service[K comparable] struct {
-	nat     *cache.LruCache[K, *conn]
-	handler Handler
+	nat       *cache.LruCache[K, *conn]
+	handler   Handler
+	handlerEx N.UDPConnectionHandlerEx
 }
 
+// Deprecated: Use NewEx instead.
 func New[K comparable](maxAge int64, handler Handler) *Service[K] {
-	return &Service[K]{
+	service := &Service[K]{
 		nat: cache.New(
 			cache.WithAge[K, *conn](maxAge),
 			cache.WithUpdateAgeOnGet[K, *conn](),
@@ -36,11 +42,27 @@ func New[K comparable](maxAge int64, handler Handler) *Service[K] {
 		),
 		handler: handler,
 	}
+	return service
+}
+
+func NewEx[K comparable](maxAge int64, handler N.UDPConnectionHandlerEx) *Service[K] {
+	service := &Service[K]{
+		nat: cache.New(
+			cache.WithAge[K, *conn](maxAge),
+			cache.WithUpdateAgeOnGet[K, *conn](),
+			cache.WithEvict[K, *conn](func(key K, conn *conn) {
+				conn.Close()
+			}),
+		),
+		handlerEx: handler,
+	}
+	return service
 }
 
 func (s *Service[T]) WriteIsThreadUnsafe() {
 }
 
+// Deprecated: don't use
 func (s *Service[T]) NewPacketDirect(ctx context.Context, key T, conn N.PacketConn, buffer *buf.Buffer, metadata M.Metadata) {
 	s.NewContextPacket(ctx, key, buffer, metadata, func(natConn N.PacketConn) (context.Context, N.PacketWriter) {
 		return ctx, &DirectBackWriter{conn, natConn}
@@ -60,18 +82,31 @@ func (w *DirectBackWriter) Upstream() any {
 	return w.Source
 }
 
+// Deprecated: use NewPacketEx instead.
 func (s *Service[T]) NewPacket(ctx context.Context, key T, buffer *buf.Buffer, metadata M.Metadata, init func(natConn N.PacketConn) N.PacketWriter) {
 	s.NewContextPacket(ctx, key, buffer, metadata, func(natConn N.PacketConn) (context.Context, N.PacketWriter) {
 		return ctx, init(natConn)
 	})
 }
 
+func (s *Service[T]) NewPacketEx(ctx context.Context, key T, buffer *buf.Buffer, source M.Socksaddr, destination M.Socksaddr, init func(natConn N.PacketConn) N.PacketWriter) {
+	s.NewContextPacketEx(ctx, key, buffer, source, destination, func(natConn N.PacketConn) (context.Context, N.PacketWriter) {
+		return ctx, init(natConn)
+	})
+}
+
+// Deprecated: Use NewPacketConnectionEx instead.
 func (s *Service[T]) NewContextPacket(ctx context.Context, key T, buffer *buf.Buffer, metadata M.Metadata, init func(natConn N.PacketConn) (context.Context, N.PacketWriter)) {
+	s.NewContextPacketEx(ctx, key, buffer, metadata.Source, metadata.Destination, init)
+}
+
+func (s *Service[T]) NewContextPacketEx(ctx context.Context, key T, buffer *buf.Buffer, source M.Socksaddr, destination M.Socksaddr, init func(natConn N.PacketConn) (context.Context, N.PacketWriter)) {
 	c, loaded := s.nat.LoadOrStore(key, func() *conn {
 		c := &conn{
-			data:       make(chan packet, 64),
-			localAddr:  metadata.Source,
-			remoteAddr: metadata.Destination,
+			data:         make(chan packet, 64),
+			localAddr:    source,
+			remoteAddr:   destination,
+			readDeadline: pipe.MakeDeadline(),
 		}
 		c.ctx, c.cancel = common.ContextWithCancelCause(ctx)
 		return c
@@ -79,26 +114,34 @@ func (s *Service[T]) NewContextPacket(ctx context.Context, key T, buffer *buf.Bu
 	if !loaded {
 		ctx, c.source = init(c)
 		go func() {
-			err := s.handler.NewPacketConnection(ctx, c, metadata)
-			if err != nil {
-				s.handler.NewError(ctx, err)
+			if s.handlerEx != nil {
+				s.handlerEx.NewPacketConnectionEx(ctx, c, source, destination, func(err error) {
+					s.nat.Delete(key)
+				})
+			} else {
+				//nolint:staticcheck
+				err := s.handler.NewPacketConnection(ctx, c, M.Metadata{
+					Source:      source,
+					Destination: destination,
+				})
+				if err != nil {
+					s.handler.NewError(ctx, err)
+				}
+				c.Close()
+				s.nat.Delete(key)
 			}
-			c.Close()
-			s.nat.Delete(key)
 		}()
-	} else {
-		c.localAddr = metadata.Source
 	}
 	if common.Done(c.ctx) {
 		s.nat.Delete(key)
 		if !common.Done(ctx) {
-			s.NewContextPacket(ctx, key, buffer, metadata, init)
+			s.NewContextPacketEx(ctx, key, buffer, source, destination, init)
 		}
 		return
 	}
 	c.data <- packet{
 		data:        buffer,
-		destination: metadata.Destination,
+		destination: destination,
 	}
 }
 
@@ -116,6 +159,7 @@ type conn struct {
 	localAddr       M.Socksaddr
 	remoteAddr      M.Socksaddr
 	source          N.PacketWriter
+	readDeadline    pipe.Deadline
 	readWaitOptions N.ReadWaitOptions
 }
 
@@ -127,6 +171,8 @@ func (c *conn) ReadPacket(buffer *buf.Buffer) (addr M.Socksaddr, err error) {
 		return p.destination, err
 	case <-c.ctx.Done():
 		return M.Socksaddr{}, io.ErrClosedPipe
+	case <-c.readDeadline.Wait():
+		return M.Socksaddr{}, os.ErrDeadlineExceeded
 	}
 }
 
@@ -159,17 +205,14 @@ func (c *conn) SetDeadline(t time.Time) error {
 }
 
 func (c *conn) SetReadDeadline(t time.Time) error {
-	return os.ErrInvalid
+	c.readDeadline.Set(t)
+	return nil
 }
 
 func (c *conn) SetWriteDeadline(t time.Time) error {
 	return os.ErrInvalid
 }
 
-func (c *conn) NeedAdditionalReadDeadline() bool {
-	return true
-}
-
 func (c *conn) Upstream() any {
 	return c.source
 }

common/udpnat2/conn.go

@@ -0,0 +1,138 @@
+package udpnat
+
+import (
+	"io"
+	"net"
+	"net/netip"
+	"os"
+	"sync"
+	"time"
+
+	"github.com/sagernet/sing/common/buf"
+	"github.com/sagernet/sing/common/canceler"
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+	"github.com/sagernet/sing/common/pipe"
+	"github.com/sagernet/sing/contrab/freelru"
+)
+
+type Conn interface {
+	N.PacketConn
+	SetHandler(handler N.UDPHandlerEx)
+	canceler.PacketConn
+}
+
+var _ Conn = (*natConn)(nil)
+
+type natConn struct {
+	cache           freelru.Cache[netip.AddrPort, *natConn]
+	writer          N.PacketWriter
+	localAddr       M.Socksaddr
+	handlerAccess   sync.RWMutex
+	handler         N.UDPHandlerEx
+	packetChan      chan *N.PacketBuffer
+	closeOnce       sync.Once
+	doneChan        chan struct{}
+	readDeadline    pipe.Deadline
+	readWaitOptions N.ReadWaitOptions
+}
+
+func (c *natConn) ReadPacket(buffer *buf.Buffer) (addr M.Socksaddr, err error) {
+	select {
+	case p := <-c.packetChan:
+		_, err = buffer.ReadOnceFrom(p.Buffer)
+		destination := p.Destination
+		p.Buffer.Release()
+		N.PutPacketBuffer(p)
+		return destination, err
+	case <-c.doneChan:
+		return M.Socksaddr{}, io.ErrClosedPipe
+	case <-c.readDeadline.Wait():
+		return M.Socksaddr{}, os.ErrDeadlineExceeded
+	}
+}
+
+func (c *natConn) WritePacket(buffer *buf.Buffer, destination M.Socksaddr) error {
+	return c.writer.WritePacket(buffer, destination)
+}
+
+func (c *natConn) InitializeReadWaiter(options N.ReadWaitOptions) (needCopy bool) {
+	c.readWaitOptions = options
+	return false
+}
+
+func (c *natConn) WaitReadPacket() (buffer *buf.Buffer, destination M.Socksaddr, err error) {
+	select {
+	case packet := <-c.packetChan:
+		buffer = c.readWaitOptions.Copy(packet.Buffer)
+		destination = packet.Destination
+		N.PutPacketBuffer(packet)
+		return
+	case <-c.doneChan:
+		return nil, M.Socksaddr{}, io.ErrClosedPipe
+	case <-c.readDeadline.Wait():
+		return nil, M.Socksaddr{}, os.ErrDeadlineExceeded
+	}
+}
+
+func (c *natConn) SetHandler(handler N.UDPHandlerEx) {
+	c.handlerAccess.Lock()
+	c.handler = handler
+	c.readWaitOptions = N.NewReadWaitOptions(c.writer, handler)
+	c.handlerAccess.Unlock()
+fetch:
+	for {
+		select {
+		case packet := <-c.packetChan:
+			c.handler.NewPacketEx(packet.Buffer, packet.Destination)
+			N.PutPacketBuffer(packet)
+			continue fetch
+		default:
+			break fetch
+		}
+	}
+}
+
+func (c *natConn) Timeout() time.Duration {
+	rawConn, lifetime, loaded := c.cache.PeekWithLifetime(c.localAddr.AddrPort())
+	if !loaded || rawConn != c {
+		return 0
+	}
+	return time.Until(lifetime)
+}
+
+func (c *natConn) SetTimeout(timeout time.Duration) bool {
+	return c.cache.UpdateLifetime(c.localAddr.AddrPort(), c, timeout)
+}
+
+func (c *natConn) Close() error {
+	c.closeOnce.Do(func() {
+		close(c.doneChan)
+	})
+	return nil
+}
+
+func (c *natConn) LocalAddr() net.Addr {
+	return c.localAddr
+}
+
+func (c *natConn) RemoteAddr() net.Addr {
+	return M.Socksaddr{}
+}
+
+func (c *natConn) SetDeadline(t time.Time) error {
+	return os.ErrInvalid
+}
+
+func (c *natConn) SetReadDeadline(t time.Time) error {
+	c.readDeadline.Set(t)
+	return nil
+}
+
+func (c *natConn) SetWriteDeadline(t time.Time) error {
+	return os.ErrInvalid
+}
+
+func (c *natConn) Upstream() any {
+	return c.writer
+}

common/udpnat2/service.go

@@ -0,0 +1,103 @@
+package udpnat
+
+import (
+	"context"
+	"net/netip"
+	"time"
+
+	"github.com/sagernet/sing/common"
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+	"github.com/sagernet/sing/common/pipe"
+	"github.com/sagernet/sing/contrab/freelru"
+	"github.com/sagernet/sing/contrab/maphash"
+)
+
+type Service struct {
+	cache   freelru.Cache[netip.AddrPort, *natConn]
+	handler N.UDPConnectionHandlerEx
+	prepare PrepareFunc
+}
+
+type PrepareFunc func(source M.Socksaddr, destination M.Socksaddr, userData any) (bool, context.Context, N.PacketWriter, N.CloseHandlerFunc)
+
+func New(handler N.UDPConnectionHandlerEx, prepare PrepareFunc, timeout time.Duration, shared bool) *Service {
+	if timeout == 0 {
+		panic("invalid timeout")
+	}
+	var cache freelru.Cache[netip.AddrPort, *natConn]
+	if !shared {
+		cache = common.Must1(freelru.NewSynced[netip.AddrPort, *natConn](1024, maphash.NewHasher[netip.AddrPort]().Hash32))
+	} else {
+		cache = common.Must1(freelru.NewSharded[netip.AddrPort, *natConn](1024, maphash.NewHasher[netip.AddrPort]().Hash32))
+	}
+	cache.SetLifetime(timeout)
+	cache.SetHealthCheck(func(port netip.AddrPort, conn *natConn) bool {
+		select {
+		case <-conn.doneChan:
+			return false
+		default:
+			return true
+		}
+	})
+	cache.SetOnEvict(func(_ netip.AddrPort, conn *natConn) {
+		conn.Close()
+	})
+	return &Service{
+		cache:   cache,
+		handler: handler,
+		prepare: prepare,
+	}
+}
+
+func (s *Service) NewPacket(bufferSlices [][]byte, source M.Socksaddr, destination M.Socksaddr, userData any) {
+	conn, _, ok := s.cache.GetAndRefreshOrAdd(source.AddrPort(), func() (*natConn, bool) {
+		ok, ctx, writer, onClose := s.prepare(source, destination, userData)
+		if !ok {
+			return nil, false
+		}
+		newConn := &natConn{
+			cache:        s.cache,
+			writer:       writer,
+			localAddr:    source,
+			packetChan:   make(chan *N.PacketBuffer, 64),
+			doneChan:     make(chan struct{}),
+			readDeadline: pipe.MakeDeadline(),
+		}
+		go s.handler.NewPacketConnectionEx(ctx, newConn, source, destination, onClose)
+		return newConn, true
+	})
+	if !ok {
+		return
+	}
+	buffer := conn.readWaitOptions.NewPacketBuffer()
+	for _, bufferSlice := range bufferSlices {
+		buffer.Write(bufferSlice)
+	}
+	conn.handlerAccess.RLock()
+	handler := conn.handler
+	conn.handlerAccess.RUnlock()
+	if handler != nil {
+		handler.NewPacketEx(buffer, destination)
+		return
+	}
+	packet := N.NewPacketBuffer()
+	*packet = N.PacketBuffer{
+		Buffer:      buffer,
+		Destination: destination,
+	}
+	select {
+	case conn.packetChan <- packet:
+	default:
+		packet.Buffer.Release()
+		N.PutPacketBuffer(packet)
+	}
+}
+
+func (s *Service) Purge() {
+	s.cache.Purge()
+}
+
+func (s *Service) PurgeExpired() {
+	s.cache.PurgeExpired()
+}

common/varbin/value_slices_unsafe_test.go

@@ -9,6 +9,7 @@ import (
 )
 
 func TestSlicesValue(t *testing.T) {
+	t.Parallel()
 	int64Arr := make([]int64, 64)
 	for i := range int64Arr {
 		int64Arr[i] = rand.Int63()
@@ -18,6 +19,7 @@ func TestSlicesValue(t *testing.T) {
 }
 
 func TestSetSliceValue(t *testing.T) {
+	t.Parallel()
 	int64Arr := make([]int64, 64)
 	value := reflect.Indirect(reflect.ValueOf(&int64Arr))
 	newInt64Arr := make([]int64, 64)

common/windnsapi/dnsapi_stub.go

@@ -0,0 +1,9 @@
+//go:build !windows
+
+package windnsapi
+
+import "os"
+
+func FlushResolverCache() error {
+	return os.ErrInvalid
+}

common/windnsapi/dnsapi_test.go

@@ -0,0 +1,14 @@
+//go:build windows
+
+package windnsapi
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestDNSAPI(t *testing.T) {
+	t.Parallel()
+	require.NoError(t, FlushResolverCache())
+}

common/windnsapi/dnsapi_windows.go

@@ -1,21 +0,0 @@
-package windnsapi
-
-import (
-	"os"
-	"syscall"
-
-	"golang.org/x/sys/windows"
-)
-
-var (
-	moddnsapi                 = windows.NewLazySystemDLL("dnsapi.dll")
-	procDnsFlushResolverCache = moddnsapi.NewProc("DnsFlushResolverCache")
-)
-
-func FlushResolverCache() error {
-	r0, _, err := syscall.SyscallN(procDnsFlushResolverCache.Addr())
-	if r0 == 0 {
-		return os.NewSyscallError("DnsFlushResolverCache", err)
-	}
-	return nil
-}

common/windnsapi/syscall_windows.go

@@ -0,0 +1,6 @@
+package windnsapi
+
+//go:generate go run golang.org/x/sys/windows/mkwinsyscall -output zsyscall_windows.go syscall_windows.go
+
+// dnsapi.DnsFlushResolverCache is an undocumented function
+//sys FlushResolverCache() (err error) = dnsapi.DnsFlushResolverCache

common/windnsapi/zsyscall_windows.go

@@ -0,0 +1,52 @@
+// Code generated by 'go generate'; DO NOT EDIT.
+
+package windnsapi
+
+import (
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+var _ unsafe.Pointer
+
+// Do the interface allocations only once for common
+// Errno values.
+const (
+	errnoERROR_IO_PENDING = 997
+)
+
+var (
+	errERROR_IO_PENDING error = syscall.Errno(errnoERROR_IO_PENDING)
+	errERROR_EINVAL     error = syscall.EINVAL
+)
+
+// errnoErr returns common boxed Errno values, to prevent
+// allocations at runtime.
+func errnoErr(e syscall.Errno) error {
+	switch e {
+	case 0:
+		return errERROR_EINVAL
+	case errnoERROR_IO_PENDING:
+		return errERROR_IO_PENDING
+	}
+	// TODO: add more here, after collecting data on the common
+	// error values see on Windows. (perhaps when running
+	// all.bat?)
+	return e
+}
+
+var (
+	moddnsapi = windows.NewLazySystemDLL("dnsapi.dll")
+
+	procDnsFlushResolverCache = moddnsapi.NewProc("DnsFlushResolverCache")
+)
+
+func FlushResolverCache() (err error) {
+	r1, _, e1 := syscall.Syscall(procDnsFlushResolverCache.Addr(), 0, 0, 0, 0)
+	if r1 == 0 {
+		err = errnoErr(e1)
+	}
+	return
+}

common/winiphlpapi/helper.go

@@ -0,0 +1,217 @@
+//go:build windows
+
+package winiphlpapi
+
+import (
+	"context"
+	"encoding/binary"
+	"net"
+	"net/netip"
+	"os"
+	"time"
+	"unsafe"
+
+	E "github.com/sagernet/sing/common/exceptions"
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+)
+
+func LoadEStats() error {
+	err := modiphlpapi.Load()
+	if err != nil {
+		return err
+	}
+	err = procGetTcpTable.Find()
+	if err != nil {
+		return err
+	}
+	err = procGetTcp6Table.Find()
+	if err != nil {
+		return err
+	}
+	err = procGetPerTcp6ConnectionEStats.Find()
+	if err != nil {
+		return err
+	}
+	err = procGetPerTcp6ConnectionEStats.Find()
+	if err != nil {
+		return err
+	}
+	err = procSetPerTcpConnectionEStats.Find()
+	if err != nil {
+		return err
+	}
+	err = procSetPerTcp6ConnectionEStats.Find()
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func LoadExtendedTable() error {
+	err := modiphlpapi.Load()
+	if err != nil {
+		return err
+	}
+	err = procGetExtendedTcpTable.Find()
+	if err != nil {
+		return err
+	}
+	err = procGetExtendedUdpTable.Find()
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func FindPid(network string, source netip.AddrPort) (uint32, error) {
+	switch N.NetworkName(network) {
+	case N.NetworkTCP:
+		if source.Addr().Is4() {
+			tcpTable, err := GetExtendedTcpTable()
+			if err != nil {
+				return 0, err
+			}
+			for _, row := range tcpTable {
+				if source == netip.AddrPortFrom(DwordToAddr(row.DwLocalAddr), DwordToPort(row.DwLocalPort)) {
+					return row.DwOwningPid, nil
+				}
+			}
+		} else {
+			tcpTable, err := GetExtendedTcp6Table()
+			if err != nil {
+				return 0, err
+			}
+			for _, row := range tcpTable {
+				if source == netip.AddrPortFrom(netip.AddrFrom16(row.UcLocalAddr), DwordToPort(row.DwLocalPort)) {
+					return row.DwOwningPid, nil
+				}
+			}
+		}
+	case N.NetworkUDP:
+		if source.Addr().Is4() {
+			udpTable, err := GetExtendedUdpTable()
+			if err != nil {
+				return 0, err
+			}
+			for _, row := range udpTable {
+				if source == netip.AddrPortFrom(DwordToAddr(row.DwLocalAddr), DwordToPort(row.DwLocalPort)) {
+					return row.DwOwningPid, nil
+				}
+			}
+		} else {
+			udpTable, err := GetExtendedUdp6Table()
+			if err != nil {
+				return 0, err
+			}
+			for _, row := range udpTable {
+				if source == netip.AddrPortFrom(netip.AddrFrom16(row.UcLocalAddr), DwordToPort(row.DwLocalPort)) {
+					return row.DwOwningPid, nil
+				}
+			}
+		}
+	}
+	return 0, E.New("process not found for ", source)
+}
+
+func WriteAndWaitAck(ctx context.Context, conn net.Conn, payload []byte) error {
+	source := M.AddrPortFromNet(conn.LocalAddr())
+	destination := M.AddrPortFromNet(conn.RemoteAddr())
+	if source.Addr().Is4() {
+		tcpTable, err := GetTcpTable()
+		if err != nil {
+			return err
+		}
+		var tcpRow *MibTcpRow
+		for _, row := range tcpTable {
+			if source == netip.AddrPortFrom(DwordToAddr(row.DwLocalAddr), DwordToPort(row.DwLocalPort)) ||
+				destination == netip.AddrPortFrom(DwordToAddr(row.DwRemoteAddr), DwordToPort(row.DwRemotePort)) {
+				tcpRow = &row
+				break
+			}
+		}
+		if tcpRow == nil {
+			return E.New("row not found for: ", source)
+		}
+		err = SetPerTcpConnectionEStatsSendBuffer(tcpRow, &TcpEstatsSendBuffRwV0{
+			EnableCollection: true,
+		})
+		if err != nil {
+			return os.NewSyscallError("SetPerTcpConnectionEStatsSendBufferV0", err)
+		}
+		defer SetPerTcpConnectionEStatsSendBuffer(tcpRow, &TcpEstatsSendBuffRwV0{
+			EnableCollection: false,
+		})
+		_, err = conn.Write(payload)
+		if err != nil {
+			return err
+		}
+		for {
+			select {
+			case <-ctx.Done():
+				return ctx.Err()
+			default:
+			}
+			eStstsSendBuffer, err := GetPerTcpConnectionEStatsSendBuffer(tcpRow)
+			if err != nil {
+				return err
+			}
+			if eStstsSendBuffer.CurRetxQueue == 0 {
+				return nil
+			}
+			time.Sleep(10 * time.Millisecond)
+		}
+	} else {
+		tcpTable, err := GetTcp6Table()
+		if err != nil {
+			return err
+		}
+		var tcpRow *MibTcp6Row
+		for _, row := range tcpTable {
+			if source == netip.AddrPortFrom(netip.AddrFrom16(row.LocalAddr), DwordToPort(row.LocalPort)) ||
+				destination == netip.AddrPortFrom(netip.AddrFrom16(row.RemoteAddr), DwordToPort(row.RemotePort)) {
+				tcpRow = &row
+				break
+			}
+		}
+		if tcpRow == nil {
+			return E.New("row not found for: ", source)
+		}
+		err = SetPerTcp6ConnectionEStatsSendBuffer(tcpRow, &TcpEstatsSendBuffRwV0{
+			EnableCollection: true,
+		})
+		if err != nil {
+			return os.NewSyscallError("SetPerTcpConnectionEStatsSendBufferV0", err)
+		}
+		defer SetPerTcp6ConnectionEStatsSendBuffer(tcpRow, &TcpEstatsSendBuffRwV0{
+			EnableCollection: false,
+		})
+		_, err = conn.Write(payload)
+		if err != nil {
+			return err
+		}
+		for {
+			select {
+			case <-ctx.Done():
+				return ctx.Err()
+			default:
+			}
+			eStstsSendBuffer, err := GetPerTcp6ConnectionEStatsSendBuffer(tcpRow)
+			if err != nil {
+				return err
+			}
+			if eStstsSendBuffer.CurRetxQueue == 0 {
+				return nil
+			}
+			time.Sleep(10 * time.Millisecond)
+		}
+	}
+}
+
+func DwordToAddr(addr uint32) netip.Addr {
+	return netip.AddrFrom4(*(*[4]byte)(unsafe.Pointer(&addr)))
+}
+
+func DwordToPort(dword uint32) uint16 {
+	return binary.BigEndian.Uint16((*[4]byte)(unsafe.Pointer(&dword))[:])
+}

common/winiphlpapi/iphlpapi.go

@@ -0,0 +1,313 @@
+//go:build windows
+
+package winiphlpapi
+
+import (
+	"errors"
+	"os"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+const (
+	TcpTableBasicListener uint32 = iota
+	TcpTableBasicConnections
+	TcpTableBasicAll
+	TcpTableOwnerPidListener
+	TcpTableOwnerPidConnections
+	TcpTableOwnerPidAll
+	TcpTableOwnerModuleListener
+	TcpTableOwnerModuleConnections
+	TcpTableOwnerModuleAll
+)
+
+const (
+	UdpTableBasic uint32 = iota
+	UdpTableOwnerPid
+	UdpTableOwnerModule
+)
+
+const (
+	TcpConnectionEstatsSynOpts uint32 = iota
+	TcpConnectionEstatsData
+	TcpConnectionEstatsSndCong
+	TcpConnectionEstatsPath
+	TcpConnectionEstatsSendBuff
+	TcpConnectionEstatsRec
+	TcpConnectionEstatsObsRec
+	TcpConnectionEstatsBandwidth
+	TcpConnectionEstatsFineRtt
+	TcpConnectionEstatsMaximum
+)
+
+type MibTcpTable struct {
+	DwNumEntries uint32
+	Table        [1]MibTcpRow
+}
+
+type MibTcpRow struct {
+	DwState      uint32
+	DwLocalAddr  uint32
+	DwLocalPort  uint32
+	DwRemoteAddr uint32
+	DwRemotePort uint32
+}
+
+type MibTcp6Table struct {
+	DwNumEntries uint32
+	Table        [1]MibTcp6Row
+}
+
+type MibTcp6Row struct {
+	State         uint32
+	LocalAddr     [16]byte
+	LocalScopeId  uint32
+	LocalPort     uint32
+	RemoteAddr    [16]byte
+	RemoteScopeId uint32
+	RemotePort    uint32
+}
+
+type MibTcpTableOwnerPid struct {
+	DwNumEntries uint32
+	Table        [1]MibTcpRowOwnerPid
+}
+
+type MibTcpRowOwnerPid struct {
+	DwState      uint32
+	DwLocalAddr  uint32
+	DwLocalPort  uint32
+	DwRemoteAddr uint32
+	DwRemotePort uint32
+	DwOwningPid  uint32
+}
+
+type MibTcp6TableOwnerPid struct {
+	DwNumEntries uint32
+	Table        [1]MibTcp6RowOwnerPid
+}
+
+type MibTcp6RowOwnerPid struct {
+	UcLocalAddr     [16]byte
+	DwLocalScopeId  uint32
+	DwLocalPort     uint32
+	UcRemoteAddr    [16]byte
+	DwRemoteScopeId uint32
+	DwRemotePort    uint32
+	DwState         uint32
+	DwOwningPid     uint32
+}
+
+type MibUdpTableOwnerPid struct {
+	DwNumEntries uint32
+	Table        [1]MibUdpRowOwnerPid
+}
+
+type MibUdpRowOwnerPid struct {
+	DwLocalAddr uint32
+	DwLocalPort uint32
+	DwOwningPid uint32
+}
+
+type MibUdp6TableOwnerPid struct {
+	DwNumEntries uint32
+	Table        [1]MibUdp6RowOwnerPid
+}
+
+type MibUdp6RowOwnerPid struct {
+	UcLocalAddr    [16]byte
+	DwLocalScopeId uint32
+	DwLocalPort    uint32
+	DwOwningPid    uint32
+}
+
+type TcpEstatsSendBufferRodV0 struct {
+	CurRetxQueue uint64
+	MaxRetxQueue uint64
+	CurAppWQueue uint64
+	MaxAppWQueue uint64
+}
+
+type TcpEstatsSendBuffRwV0 struct {
+	EnableCollection bool
+}
+
+const (
+	offsetOfMibTcpTable            = unsafe.Offsetof(MibTcpTable{}.Table)
+	offsetOfMibTcp6Table           = unsafe.Offsetof(MibTcp6Table{}.Table)
+	offsetOfMibTcpTableOwnerPid    = unsafe.Offsetof(MibTcpTableOwnerPid{}.Table)
+	offsetOfMibTcp6TableOwnerPid   = unsafe.Offsetof(MibTcpTableOwnerPid{}.Table)
+	offsetOfMibUdpTableOwnerPid    = unsafe.Offsetof(MibUdpTableOwnerPid{}.Table)
+	offsetOfMibUdp6TableOwnerPid   = unsafe.Offsetof(MibUdp6TableOwnerPid{}.Table)
+	sizeOfTcpEstatsSendBuffRwV0    = unsafe.Sizeof(TcpEstatsSendBuffRwV0{})
+	sizeOfTcpEstatsSendBufferRodV0 = unsafe.Sizeof(TcpEstatsSendBufferRodV0{})
+)
+
+func GetTcpTable() ([]MibTcpRow, error) {
+	var size uint32
+	err := getTcpTable(nil, &size, false)
+	if !errors.Is(err, windows.ERROR_INSUFFICIENT_BUFFER) {
+		return nil, err
+	}
+	for {
+		table := make([]byte, size)
+		err = getTcpTable(&table[0], &size, false)
+		if err != nil {
+			if errors.Is(err, windows.ERROR_INSUFFICIENT_BUFFER) {
+				continue
+			}
+			return nil, err
+		}
+		dwNumEntries := int(*(*uint32)(unsafe.Pointer(&table[0])))
+		return unsafe.Slice((*MibTcpRow)(unsafe.Pointer(&table[offsetOfMibTcpTable])), dwNumEntries), nil
+	}
+}
+
+func GetTcp6Table() ([]MibTcp6Row, error) {
+	var size uint32
+	err := getTcp6Table(nil, &size, false)
+	if !errors.Is(err, windows.ERROR_INSUFFICIENT_BUFFER) {
+		return nil, err
+	}
+	for {
+		table := make([]byte, size)
+		err = getTcp6Table(&table[0], &size, false)
+		if err != nil {
+			if errors.Is(err, windows.ERROR_INSUFFICIENT_BUFFER) {
+				continue
+			}
+			return nil, err
+		}
+		dwNumEntries := int(*(*uint32)(unsafe.Pointer(&table[0])))
+		return unsafe.Slice((*MibTcp6Row)(unsafe.Pointer(&table[offsetOfMibTcp6Table])), dwNumEntries), nil
+	}
+}
+
+func GetExtendedTcpTable() ([]MibTcpRowOwnerPid, error) {
+	var size uint32
+	err := getExtendedTcpTable(nil, &size, false, windows.AF_INET, TcpTableOwnerPidConnections, 0)
+	if !errors.Is(err, windows.ERROR_INSUFFICIENT_BUFFER) {
+		return nil, os.NewSyscallError("GetExtendedTcpTable", err)
+	}
+	for {
+		table := make([]byte, size)
+		err = getExtendedTcpTable(&table[0], &size, false, windows.AF_INET, TcpTableOwnerPidConnections, 0)
+		if err != nil {
+			if errors.Is(err, windows.ERROR_INSUFFICIENT_BUFFER) {
+				continue
+			}
+			return nil, os.NewSyscallError("GetExtendedTcpTable", err)
+		}
+		dwNumEntries := int(*(*uint32)(unsafe.Pointer(&table[0])))
+		return unsafe.Slice((*MibTcpRowOwnerPid)(unsafe.Pointer(&table[offsetOfMibTcpTableOwnerPid])), dwNumEntries), nil
+	}
+}
+
+func GetExtendedTcp6Table() ([]MibTcp6RowOwnerPid, error) {
+	var size uint32
+	err := getExtendedTcpTable(nil, &size, false, windows.AF_INET6, TcpTableOwnerPidConnections, 0)
+	if !errors.Is(err, windows.ERROR_INSUFFICIENT_BUFFER) {
+		return nil, os.NewSyscallError("GetExtendedTcpTable", err)
+	}
+	for {
+		table := make([]byte, size)
+		err = getExtendedTcpTable(&table[0], &size, false, windows.AF_INET6, TcpTableOwnerPidConnections, 0)
+		if err != nil {
+			if errors.Is(err, windows.ERROR_INSUFFICIENT_BUFFER) {
+				continue
+			}
+			return nil, os.NewSyscallError("GetExtendedTcpTable", err)
+		}
+		dwNumEntries := int(*(*uint32)(unsafe.Pointer(&table[0])))
+		return unsafe.Slice((*MibTcp6RowOwnerPid)(unsafe.Pointer(&table[offsetOfMibTcp6TableOwnerPid])), dwNumEntries), nil
+	}
+}
+
+func GetExtendedUdpTable() ([]MibUdpRowOwnerPid, error) {
+	var size uint32
+	err := getExtendedUdpTable(nil, &size, false, windows.AF_INET, UdpTableOwnerPid, 0)
+	if !errors.Is(err, windows.ERROR_INSUFFICIENT_BUFFER) {
+		return nil, os.NewSyscallError("GetExtendedUdpTable", err)
+	}
+	for {
+		table := make([]byte, size)
+		err = getExtendedUdpTable(&table[0], &size, false, windows.AF_INET, UdpTableOwnerPid, 0)
+		if err != nil {
+			if errors.Is(err, windows.ERROR_INSUFFICIENT_BUFFER) {
+				continue
+			}
+			return nil, os.NewSyscallError("GetExtendedUdpTable", err)
+		}
+		dwNumEntries := int(*(*uint32)(unsafe.Pointer(&table[0])))
+		return unsafe.Slice((*MibUdpRowOwnerPid)(unsafe.Pointer(&table[offsetOfMibUdpTableOwnerPid])), dwNumEntries), nil
+	}
+}
+
+func GetExtendedUdp6Table() ([]MibUdp6RowOwnerPid, error) {
+	var size uint32
+	err := getExtendedUdpTable(nil, &size, false, windows.AF_INET6, UdpTableOwnerPid, 0)
+	if !errors.Is(err, windows.ERROR_INSUFFICIENT_BUFFER) {
+		return nil, os.NewSyscallError("GetExtendedUdpTable", err)
+	}
+	for {
+		table := make([]byte, size)
+		err = getExtendedUdpTable(&table[0], &size, false, windows.AF_INET6, UdpTableOwnerPid, 0)
+		if err != nil {
+			if errors.Is(err, windows.ERROR_INSUFFICIENT_BUFFER) {
+				continue
+			}
+			return nil, os.NewSyscallError("GetExtendedUdpTable", err)
+		}
+		dwNumEntries := int(*(*uint32)(unsafe.Pointer(&table[0])))
+		return unsafe.Slice((*MibUdp6RowOwnerPid)(unsafe.Pointer(&table[offsetOfMibUdp6TableOwnerPid])), dwNumEntries), nil
+	}
+}
+
+func GetPerTcpConnectionEStatsSendBuffer(row *MibTcpRow) (*TcpEstatsSendBufferRodV0, error) {
+	var rod TcpEstatsSendBufferRodV0
+	err := getPerTcpConnectionEStats(row,
+		TcpConnectionEstatsSendBuff,
+		0,
+		0,
+		0,
+		0,
+		0,
+		0,
+		uintptr(unsafe.Pointer(&rod)),
+		0,
+		uint64(sizeOfTcpEstatsSendBufferRodV0),
+	)
+	if err != nil {
+		return nil, err
+	}
+	return &rod, nil
+}
+
+func GetPerTcp6ConnectionEStatsSendBuffer(row *MibTcp6Row) (*TcpEstatsSendBufferRodV0, error) {
+	var rod TcpEstatsSendBufferRodV0
+	err := getPerTcp6ConnectionEStats(row,
+		TcpConnectionEstatsSendBuff,
+		0,
+		0,
+		0,
+		0,
+		0,
+		0,
+		uintptr(unsafe.Pointer(&rod)),
+		0,
+		uint64(sizeOfTcpEstatsSendBufferRodV0),
+	)
+	if err != nil {
+		return nil, err
+	}
+	return &rod, nil
+}
+
+func SetPerTcpConnectionEStatsSendBuffer(row *MibTcpRow, rw *TcpEstatsSendBuffRwV0) error {
+	return setPerTcpConnectionEStats(row, TcpConnectionEstatsSendBuff, uintptr(unsafe.Pointer(&rw)), 0, uint64(sizeOfTcpEstatsSendBuffRwV0), 0)
+}
+
+func SetPerTcp6ConnectionEStatsSendBuffer(row *MibTcp6Row, rw *TcpEstatsSendBuffRwV0) error {
+	return setPerTcp6ConnectionEStats(row, TcpConnectionEstatsSendBuff, uintptr(unsafe.Pointer(&rw)), 0, uint64(sizeOfTcpEstatsSendBuffRwV0), 0)
+}

common/winiphlpapi/iphlpapi_test.go

@@ -0,0 +1,90 @@
+//go:build windows
+
+package winiphlpapi_test
+
+import (
+	"context"
+	"net"
+	"syscall"
+	"testing"
+
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+	"github.com/sagernet/sing/common/winiphlpapi"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestFindPidTcp4(t *testing.T) {
+	t.Parallel()
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	require.NoError(t, err)
+	defer listener.Close()
+	go listener.Accept()
+	conn, err := net.Dial("tcp", listener.Addr().String())
+	require.NoError(t, err)
+	defer conn.Close()
+	pid, err := winiphlpapi.FindPid(N.NetworkTCP, M.AddrPortFromNet(conn.LocalAddr()))
+	require.NoError(t, err)
+	require.Equal(t, uint32(syscall.Getpid()), pid)
+}
+
+func TestFindPidTcp6(t *testing.T) {
+	t.Parallel()
+	listener, err := net.Listen("tcp", "[::1]:0")
+	require.NoError(t, err)
+	defer listener.Close()
+	go listener.Accept()
+	conn, err := net.Dial("tcp", listener.Addr().String())
+	require.NoError(t, err)
+	defer conn.Close()
+	pid, err := winiphlpapi.FindPid(N.NetworkTCP, M.AddrPortFromNet(conn.LocalAddr()))
+	require.NoError(t, err)
+	require.Equal(t, uint32(syscall.Getpid()), pid)
+}
+
+func TestFindPidUdp4(t *testing.T) {
+	t.Parallel()
+	conn, err := net.ListenPacket("udp", "127.0.0.1:0")
+	require.NoError(t, err)
+	defer conn.Close()
+	pid, err := winiphlpapi.FindPid(N.NetworkUDP, M.AddrPortFromNet(conn.LocalAddr()))
+	require.NoError(t, err)
+	require.Equal(t, uint32(syscall.Getpid()), pid)
+}
+
+func TestFindPidUdp6(t *testing.T) {
+	t.Parallel()
+	conn, err := net.ListenPacket("udp", "[::1]:0")
+	require.NoError(t, err)
+	defer conn.Close()
+	pid, err := winiphlpapi.FindPid(N.NetworkUDP, M.AddrPortFromNet(conn.LocalAddr()))
+	require.NoError(t, err)
+	require.Equal(t, uint32(syscall.Getpid()), pid)
+}
+
+func TestWaitAck4(t *testing.T) {
+	t.Parallel()
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	require.NoError(t, err)
+	defer listener.Close()
+	go listener.Accept()
+	conn, err := net.Dial("tcp", listener.Addr().String())
+	require.NoError(t, err)
+	defer conn.Close()
+	err = winiphlpapi.WriteAndWaitAck(context.Background(), conn, []byte("hello"))
+	require.NoError(t, err)
+}
+
+func TestWaitAck6(t *testing.T) {
+	t.Parallel()
+	listener, err := net.Listen("tcp", "[::1]:0")
+	require.NoError(t, err)
+	defer listener.Close()
+	go listener.Accept()
+	conn, err := net.Dial("tcp", listener.Addr().String())
+	require.NoError(t, err)
+	defer conn.Close()
+	err = winiphlpapi.WriteAndWaitAck(context.Background(), conn, []byte("hello"))
+	require.NoError(t, err)
+}

common/winiphlpapi/syscall_windows.go

@@ -0,0 +1,27 @@
+package winiphlpapi
+
+//go:generate go run golang.org/x/sys/windows/mkwinsyscall -output zsyscall_windows.go syscall_windows.go
+
+// https://learn.microsoft.com/en-us/windows/win32/api/iphlpapi/nf-iphlpapi-gettcptable
+//sys getTcpTable(tcpTable *byte, sizePointer *uint32, order bool) (errcode error) = iphlpapi.GetTcpTable
+
+// https://learn.microsoft.com/en-us/windows/win32/api/iphlpapi/nf-iphlpapi-gettcp6table
+//sys getTcp6Table(tcpTable *byte, sizePointer *uint32, order bool) (errcode error) = iphlpapi.GetTcp6Table
+
+// https://learn.microsoft.com/en-us/windows/win32/api/iphlpapi/nf-iphlpapi-getpertcpconnectionestats
+//sys getPerTcpConnectionEStats(row *MibTcpRow, estatsType uint32, rw uintptr, rwVersion uint64, rwSize uint64, ros uintptr, rosVersion uint64, rosSize uint64, rod uintptr, rodVersion uint64, rodSize uint64) (errcode error) = iphlpapi.GetPerTcpConnectionEStats
+
+// https://learn.microsoft.com/en-us/windows/win32/api/iphlpapi/nf-iphlpapi-getpertcp6connectionestats
+//sys getPerTcp6ConnectionEStats(row *MibTcp6Row, estatsType uint32, rw uintptr, rwVersion uint64, rwSize uint64, ros uintptr, rosVersion uint64, rosSize uint64, rod uintptr, rodVersion uint64, rodSize uint64) (errcode error) = iphlpapi.GetPerTcp6ConnectionEStats
+
+// https://learn.microsoft.com/en-us/windows/win32/api/iphlpapi/nf-iphlpapi-setpertcpconnectionestats
+//sys setPerTcpConnectionEStats(row *MibTcpRow, estatsType uint32, rw uintptr, rwVersion uint64, rwSize uint64, offset uint64) (errcode error) = iphlpapi.SetPerTcpConnectionEStats
+
+// https://learn.microsoft.com/en-us/windows/win32/api/iphlpapi/nf-iphlpapi-setpertcp6connectionestats
+//sys setPerTcp6ConnectionEStats(row *MibTcp6Row, estatsType uint32, rw uintptr, rwVersion uint64, rwSize uint64, offset uint64) (errcode error) = iphlpapi.SetPerTcp6ConnectionEStats
+
+// https://learn.microsoft.com/en-us/windows/win32/api/iphlpapi/nf-iphlpapi-getextendedtcptable
+//sys getExtendedTcpTable(pTcpTable *byte, pdwSize *uint32, bOrder bool, ulAf uint64, tableClass uint32, reserved uint64) = (errcode error) = iphlpapi.GetExtendedTcpTable
+
+// https://learn.microsoft.com/en-us/windows/win32/api/iphlpapi/nf-iphlpapi-getextendedudptable
+//sys getExtendedUdpTable(pUdpTable *byte, pdwSize *uint32, bOrder bool, ulAf uint64, tableClass uint32, reserved uint64) = (errcode error) = iphlpapi.GetExtendedUdpTable

common/winiphlpapi/zsyscall_windows.go

@@ -0,0 +1,131 @@
+// Code generated by 'go generate'; DO NOT EDIT.
+
+package winiphlpapi
+
+import (
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+var _ unsafe.Pointer
+
+// Do the interface allocations only once for common
+// Errno values.
+const (
+	errnoERROR_IO_PENDING = 997
+)
+
+var (
+	errERROR_IO_PENDING error = syscall.Errno(errnoERROR_IO_PENDING)
+	errERROR_EINVAL     error = syscall.EINVAL
+)
+
+// errnoErr returns common boxed Errno values, to prevent
+// allocations at runtime.
+func errnoErr(e syscall.Errno) error {
+	switch e {
+	case 0:
+		return errERROR_EINVAL
+	case errnoERROR_IO_PENDING:
+		return errERROR_IO_PENDING
+	}
+	// TODO: add more here, after collecting data on the common
+	// error values see on Windows. (perhaps when running
+	// all.bat?)
+	return e
+}
+
+var (
+	modiphlpapi = windows.NewLazySystemDLL("iphlpapi.dll")
+
+	procGetExtendedTcpTable        = modiphlpapi.NewProc("GetExtendedTcpTable")
+	procGetExtendedUdpTable        = modiphlpapi.NewProc("GetExtendedUdpTable")
+	procGetPerTcp6ConnectionEStats = modiphlpapi.NewProc("GetPerTcp6ConnectionEStats")
+	procGetPerTcpConnectionEStats  = modiphlpapi.NewProc("GetPerTcpConnectionEStats")
+	procGetTcp6Table               = modiphlpapi.NewProc("GetTcp6Table")
+	procGetTcpTable                = modiphlpapi.NewProc("GetTcpTable")
+	procSetPerTcp6ConnectionEStats = modiphlpapi.NewProc("SetPerTcp6ConnectionEStats")
+	procSetPerTcpConnectionEStats  = modiphlpapi.NewProc("SetPerTcpConnectionEStats")
+)
+
+func getExtendedTcpTable(pTcpTable *byte, pdwSize *uint32, bOrder bool, ulAf uint64, tableClass uint32, reserved uint64) (errcode error) {
+	var _p0 uint32
+	if bOrder {
+		_p0 = 1
+	}
+	r0, _, _ := syscall.Syscall6(procGetExtendedTcpTable.Addr(), 6, uintptr(unsafe.Pointer(pTcpTable)), uintptr(unsafe.Pointer(pdwSize)), uintptr(_p0), uintptr(ulAf), uintptr(tableClass), uintptr(reserved))
+	if r0 != 0 {
+		errcode = syscall.Errno(r0)
+	}
+	return
+}
+
+func getExtendedUdpTable(pUdpTable *byte, pdwSize *uint32, bOrder bool, ulAf uint64, tableClass uint32, reserved uint64) (errcode error) {
+	var _p0 uint32
+	if bOrder {
+		_p0 = 1
+	}
+	r0, _, _ := syscall.Syscall6(procGetExtendedUdpTable.Addr(), 6, uintptr(unsafe.Pointer(pUdpTable)), uintptr(unsafe.Pointer(pdwSize)), uintptr(_p0), uintptr(ulAf), uintptr(tableClass), uintptr(reserved))
+	if r0 != 0 {
+		errcode = syscall.Errno(r0)
+	}
+	return
+}
+
+func getPerTcp6ConnectionEStats(row *MibTcp6Row, estatsType uint32, rw uintptr, rwVersion uint64, rwSize uint64, ros uintptr, rosVersion uint64, rosSize uint64, rod uintptr, rodVersion uint64, rodSize uint64) (errcode error) {
+	r0, _, _ := syscall.Syscall12(procGetPerTcp6ConnectionEStats.Addr(), 11, uintptr(unsafe.Pointer(row)), uintptr(estatsType), uintptr(rw), uintptr(rwVersion), uintptr(rwSize), uintptr(ros), uintptr(rosVersion), uintptr(rosSize), uintptr(rod), uintptr(rodVersion), uintptr(rodSize), 0)
+	if r0 != 0 {
+		errcode = syscall.Errno(r0)
+	}
+	return
+}
+
+func getPerTcpConnectionEStats(row *MibTcpRow, estatsType uint32, rw uintptr, rwVersion uint64, rwSize uint64, ros uintptr, rosVersion uint64, rosSize uint64, rod uintptr, rodVersion uint64, rodSize uint64) (errcode error) {
+	r0, _, _ := syscall.Syscall12(procGetPerTcpConnectionEStats.Addr(), 11, uintptr(unsafe.Pointer(row)), uintptr(estatsType), uintptr(rw), uintptr(rwVersion), uintptr(rwSize), uintptr(ros), uintptr(rosVersion), uintptr(rosSize), uintptr(rod), uintptr(rodVersion), uintptr(rodSize), 0)
+	if r0 != 0 {
+		errcode = syscall.Errno(r0)
+	}
+	return
+}
+
+func getTcp6Table(tcpTable *byte, sizePointer *uint32, order bool) (errcode error) {
+	var _p0 uint32
+	if order {
+		_p0 = 1
+	}
+	r0, _, _ := syscall.Syscall(procGetTcp6Table.Addr(), 3, uintptr(unsafe.Pointer(tcpTable)), uintptr(unsafe.Pointer(sizePointer)), uintptr(_p0))
+	if r0 != 0 {
+		errcode = syscall.Errno(r0)
+	}
+	return
+}
+
+func getTcpTable(tcpTable *byte, sizePointer *uint32, order bool) (errcode error) {
+	var _p0 uint32
+	if order {
+		_p0 = 1
+	}
+	r0, _, _ := syscall.Syscall(procGetTcpTable.Addr(), 3, uintptr(unsafe.Pointer(tcpTable)), uintptr(unsafe.Pointer(sizePointer)), uintptr(_p0))
+	if r0 != 0 {
+		errcode = syscall.Errno(r0)
+	}
+	return
+}
+
+func setPerTcp6ConnectionEStats(row *MibTcp6Row, estatsType uint32, rw uintptr, rwVersion uint64, rwSize uint64, offset uint64) (errcode error) {
+	r0, _, _ := syscall.Syscall6(procSetPerTcp6ConnectionEStats.Addr(), 6, uintptr(unsafe.Pointer(row)), uintptr(estatsType), uintptr(rw), uintptr(rwVersion), uintptr(rwSize), uintptr(offset))
+	if r0 != 0 {
+		errcode = syscall.Errno(r0)
+	}
+	return
+}
+
+func setPerTcpConnectionEStats(row *MibTcpRow, estatsType uint32, rw uintptr, rwVersion uint64, rwSize uint64, offset uint64) (errcode error) {
+	r0, _, _ := syscall.Syscall6(procSetPerTcpConnectionEStats.Addr(), 6, uintptr(unsafe.Pointer(row)), uintptr(estatsType), uintptr(rw), uintptr(rwVersion), uintptr(rwSize), uintptr(offset))
+	if r0 != 0 {
+		errcode = syscall.Errno(r0)
+	}
+	return
+}

common/winpowrprof/event.go

@@ -6,6 +6,8 @@ const (
 	EVENT_RESUME_AUTOMATIC // Because the user is not present, most applications should do nothing.
 )
 
+type EventCallback = func(event int)
+
 type EventListener interface {
 	Start() error
 	Close() error

common/winpowrprof/event_stub.go

@@ -6,6 +6,6 @@ import (
 	"os"
 )
 
-func NewEventListener(callback func(event int)) (EventListener, error) {
+func NewEventListener(callback EventCallback) (EventListener, error) {
 	return nil, os.ErrInvalid
 }

common/winpowrprof/event_test.go

@@ -11,6 +11,7 @@ func TestPowerEvents(t *testing.T) {
 	if runtime.GOOS != "windows" {
 		t.SkipNow()
 	}
+	t.Parallel()
 	listener, err := NewEventListener(func(event int) {})
 	require.NoError(t, err)
 	require.NotNil(t, listener)

common/winpowrprof/event_windows.go

@@ -3,81 +3,75 @@ package winpowrprof
 // modify from https://github.com/golang/go/blob/b634f6fdcbebee23b7da709a243f3db217b64776/src/runtime/os_windows.go#L257
 
 import (
-	"syscall"
 	"unsafe"
 
 	"golang.org/x/sys/windows"
 )
 
-var (
-	modpowerprof                                 = windows.NewLazySystemDLL("powrprof.dll")
-	procPowerRegisterSuspendResumeNotification   = modpowerprof.NewProc("PowerRegisterSuspendResumeNotification")
-	procPowerUnregisterSuspendResumeNotification = modpowerprof.NewProc("PowerUnregisterSuspendResumeNotification")
-)
-
-const (
-	PBT_APMSUSPEND         uint32 = 4
-	PBT_APMRESUMESUSPEND   uint32 = 7
-	PBT_APMRESUMEAUTOMATIC uint32 = 18
-)
-
-const (
-	_DEVICE_NOTIFY_CALLBACK = 2
-)
-
-type _DEVICE_NOTIFY_SUBSCRIBE_PARAMETERS struct {
-	callback uintptr
-	context  uintptr
+type powerEventListener struct {
+	pinner   myPinner
+	callback EventCallback
+	handle   uintptr
 }
 
-type eventListener struct {
-	params _DEVICE_NOTIFY_SUBSCRIBE_PARAMETERS
-	handle uintptr
-}
-
-func NewEventListener(callback func(event int)) (EventListener, error) {
-	if err := procPowerRegisterSuspendResumeNotification.Find(); err != nil {
+func NewEventListener(callback EventCallback) (EventListener, error) {
+	err := procPowerRegisterSuspendResumeNotification.Find()
+	if err != nil {
 		return nil, err // Running on Windows 7, where we don't need it anyway.
 	}
-	if err := procPowerUnregisterSuspendResumeNotification.Find(); err != nil {
+	err = procPowerUnregisterSuspendResumeNotification.Find()
+	if err != nil {
 		return nil, err // Running on Windows 7, where we don't need it anyway.
 	}
-
-	var fn interface{} = func(context uintptr, changeType uint32, setting uintptr) uintptr {
-		switch changeType {
-		case PBT_APMSUSPEND:
-			callback(EVENT_SUSPEND)
-		case PBT_APMRESUMESUSPEND:
-			callback(EVENT_RESUME)
-		case PBT_APMRESUMEAUTOMATIC:
-			callback(EVENT_RESUME_AUTOMATIC)
-		}
-		return 0
-	}
-	return &eventListener{
-		params: _DEVICE_NOTIFY_SUBSCRIBE_PARAMETERS{
-			callback: windows.NewCallback(fn),
-		},
+	return &powerEventListener{
+		callback: callback,
 	}, nil
 }
 
-func (l *eventListener) Start() error {
-	_, _, errno := syscall.SyscallN(
-		procPowerRegisterSuspendResumeNotification.Addr(),
-		_DEVICE_NOTIFY_CALLBACK,
-		uintptr(unsafe.Pointer(&l.params)),
-		uintptr(unsafe.Pointer(&l.handle)),
+func (l *powerEventListener) Start() error {
+	l.pinner.Pin(&l.callback)
+	params := DEVICE_NOTIFY_SUBSCRIBE_PARAMETERS{
+		callback: windows.NewCallback(suspendResumeNotificationCallback),
+		context:  unsafe.Pointer(&l.callback),
+	}
+	err := PowerRegisterSuspendResumeNotification(
+		DEVICE_NOTIFY_CALLBACK,
+		&params,
+		&l.handle,
 	)
-	if errno != 0 {
-		return errno
+	if err != nil {
+		l.pinner.Unpin()
+		return err
 	}
 	return nil
 }
 
-func (l *eventListener) Close() error {
-	_, _, errno := syscall.SyscallN(procPowerUnregisterSuspendResumeNotification.Addr(), uintptr(unsafe.Pointer(&l.handle)))
-	if errno != 0 {
-		return errno
+func (l *powerEventListener) Close() error {
+	if l.handle == 0 {
+		return nil
 	}
+	defer l.pinner.Unpin()
+	err := PowerUnregisterSuspendResumeNotification(l.handle)
+	if err != nil {
+		return err
+	}
+	l.handle = 0
 	return nil
 }
+
+func suspendResumeNotificationCallback(context *EventCallback, changeType uint32, setting uintptr) uintptr {
+	callback := *context
+	var event int
+	switch changeType {
+	case PBT_APMSUSPEND:
+		event = EVENT_SUSPEND
+	case PBT_APMRESUMESUSPEND:
+		event = EVENT_RESUME
+	case PBT_APMRESUMEAUTOMATIC:
+		event = EVENT_RESUME_AUTOMATIC
+	default:
+		return 0
+	}
+	callback(event)
+	return 0
+}

common/winpowrprof/pinner.go

@@ -0,0 +1,7 @@
+//go:build go1.21
+
+package winpowrprof
+
+import "runtime"
+
+type myPinner = runtime.Pinner

common/winpowrprof/pinner_compat.go

@@ -0,0 +1,11 @@
+//go:build !go1.21
+
+package winpowrprof
+
+type myPinner struct{}
+
+func (p *myPinner) Pin(pointer any) {
+}
+
+func (p *myPinner) Unpin() {
+}

common/winpowrprof/syscall_windows.go

@@ -0,0 +1,24 @@
+package winpowrprof
+
+import "unsafe"
+
+//go:generate go run golang.org/x/sys/windows/mkwinsyscall -output zsyscall_windows.go syscall_windows.go
+
+const DEVICE_NOTIFY_CALLBACK = 2
+
+type DEVICE_NOTIFY_SUBSCRIBE_PARAMETERS struct {
+	callback uintptr
+	context  unsafe.Pointer
+}
+
+// https://learn.microsoft.com/en-us/windows/win32/api/powerbase/nf-powerbase-powerregistersuspendresumenotification
+//sys PowerRegisterSuspendResumeNotification(flags uint32, recipient *DEVICE_NOTIFY_SUBSCRIBE_PARAMETERS, registrationHandle *uintptr) (ret error) = powrprof.PowerRegisterSuspendResumeNotification
+
+// https://learn.microsoft.com/en-us/windows/win32/api/powerbase/nf-powerbase-powerunregistersuspendresumenotification
+//sys PowerUnregisterSuspendResumeNotification(handle uintptr) (ret error) = powrprof.PowerUnregisterSuspendResumeNotification
+
+const (
+	PBT_APMSUSPEND         uint32 = 4
+	PBT_APMRESUMESUSPEND   uint32 = 7
+	PBT_APMRESUMEAUTOMATIC uint32 = 18
+)

common/winpowrprof/zsyscall_windows.go

@@ -0,0 +1,61 @@
+// Code generated by 'go generate'; DO NOT EDIT.
+
+package winpowrprof
+
+import (
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+var _ unsafe.Pointer
+
+// Do the interface allocations only once for common
+// Errno values.
+const (
+	errnoERROR_IO_PENDING = 997
+)
+
+var (
+	errERROR_IO_PENDING error = syscall.Errno(errnoERROR_IO_PENDING)
+	errERROR_EINVAL     error = syscall.EINVAL
+)
+
+// errnoErr returns common boxed Errno values, to prevent
+// allocations at runtime.
+func errnoErr(e syscall.Errno) error {
+	switch e {
+	case 0:
+		return errERROR_EINVAL
+	case errnoERROR_IO_PENDING:
+		return errERROR_IO_PENDING
+	}
+	// TODO: add more here, after collecting data on the common
+	// error values see on Windows. (perhaps when running
+	// all.bat?)
+	return e
+}
+
+var (
+	modpowrprof = windows.NewLazySystemDLL("powrprof.dll")
+
+	procPowerRegisterSuspendResumeNotification   = modpowrprof.NewProc("PowerRegisterSuspendResumeNotification")
+	procPowerUnregisterSuspendResumeNotification = modpowrprof.NewProc("PowerUnregisterSuspendResumeNotification")
+)
+
+func PowerRegisterSuspendResumeNotification(flags uint32, recipient *DEVICE_NOTIFY_SUBSCRIBE_PARAMETERS, registrationHandle *uintptr) (ret error) {
+	r0, _, _ := syscall.Syscall(procPowerRegisterSuspendResumeNotification.Addr(), 3, uintptr(flags), uintptr(unsafe.Pointer(recipient)), uintptr(unsafe.Pointer(registrationHandle)))
+	if r0 != 0 {
+		ret = syscall.Errno(r0)
+	}
+	return
+}
+
+func PowerUnregisterSuspendResumeNotification(handle uintptr) (ret error) {
+	r0, _, _ := syscall.Syscall(procPowerUnregisterSuspendResumeNotification.Addr(), 1, uintptr(handle), 0, 0)
+	if r0 != 0 {
+		ret = syscall.Errno(r0)
+	}
+	return
+}