Fix socks5 packet conn

common/bufio/nat.go

@@ -63,6 +63,10 @@ func (c *unidirectionalNATPacketConn) UpdateDestination(destinationAddress netip
 	c.destination = M.SocksaddrFrom(destinationAddress, c.destination.Port)
 }
 
+func (c *unidirectionalNATPacketConn) RemoteAddr() net.Addr {
+	return c.destination.UDPAddr()
+}
+
 func (c *unidirectionalNATPacketConn) Upstream() any {
 	return c.NetPacketConn
 }
@@ -136,6 +140,10 @@ func (c *bidirectionalNATPacketConn) Upstream() any {
 	return c.NetPacketConn
 }
 
+func (c *bidirectionalNATPacketConn) RemoteAddr() net.Addr {
+	return c.destination.UDPAddr()
+}
+
 func socksaddrWithoutPort(destination M.Socksaddr) M.Socksaddr {
 	destination.Port = 0
 	return destination

protocol/socks/client.go

@@ -7,7 +7,6 @@ import (
 	"os"
 	"strings"
 
-	"github.com/sagernet/sing/common/bufio"
 	E "github.com/sagernet/sing/common/exceptions"
 	M "github.com/sagernet/sing/common/metadata"
 	N "github.com/sagernet/sing/common/network"
@@ -148,7 +147,7 @@ func (c *Client) DialContext(ctx context.Context, network string, address M.Sock
 			tcpConn.Close()
 			return nil, err
 		}
-		return NewAssociatePacketConn(bufio.NewUnbindPacketConn(udpConn), address, tcpConn), nil
+		return NewAssociatePacketConn(udpConn, address, tcpConn), nil
 	}
 	return nil, os.ErrInvalid
 }

protocol/socks/packet.go

@@ -21,54 +21,41 @@ import (
 var ErrInvalidPacket = E.New("socks5: invalid packet")
 
 type AssociatePacketConn struct {
-	N.NetPacketConn
+	N.AbstractConn
+	conn       N.ExtendedConn
 	remoteAddr M.Socksaddr
 	underlying net.Conn
 }
 
-func NewAssociatePacketConn(conn net.PacketConn, remoteAddr M.Socksaddr, underlying net.Conn) *AssociatePacketConn {
+func NewAssociatePacketConn(conn net.Conn, remoteAddr M.Socksaddr, underlying net.Conn) *AssociatePacketConn {
 	return &AssociatePacketConn{
-		NetPacketConn: bufio.NewPacketConn(conn),
+		AbstractConn: conn,
+		conn:         bufio.NewExtendedConn(conn),
 		remoteAddr:   remoteAddr,
 		underlying:   underlying,
 	}
 }
 
-// Deprecated: NewAssociatePacketConn(bufio.NewUnbindPacketConn(conn), remoteAddr, underlying) instead.
-func NewAssociateConn(conn net.Conn, remoteAddr M.Socksaddr, underlying net.Conn) *AssociatePacketConn {
-	return &AssociatePacketConn{
-		NetPacketConn: bufio.NewUnbindPacketConn(conn),
-		remoteAddr:    remoteAddr,
-		underlying:    underlying,
-	}
-}
-
-func (c *AssociatePacketConn) RemoteAddr() net.Addr {
-	return c.remoteAddr.UDPAddr()
-}
-
-//warn:unsafe
 func (c *AssociatePacketConn) ReadFrom(p []byte) (n int, addr net.Addr, err error) {
-	n, addr, err = c.NetPacketConn.ReadFrom(p)
+	n, err = c.conn.Read(p)
 	if err != nil {
 		return
 	}
 	if n < 3 {
 		return 0, nil, ErrInvalidPacket
 	}
-	c.remoteAddr = M.SocksaddrFromNet(addr)
 	reader := bytes.NewReader(p[3:n])
 	destination, err := M.SocksaddrSerializer.ReadAddrPort(reader)
 	if err != nil {
 		return
 	}
+	c.remoteAddr = destination
 	addr = destination.UDPAddr()
 	index := 3 + int(reader.Size()) - reader.Len()
 	n = copy(p, p[index:n])
 	return
 }
 
-//warn:unsafe
 func (c *AssociatePacketConn) WriteTo(p []byte, addr net.Addr) (n int, err error) {
 	destination := M.SocksaddrFromNet(addr)
 	buffer := buf.NewSize(3 + M.SocksaddrSerializer.AddrPortLen(destination) + len(p))
@@ -82,7 +69,34 @@ func (c *AssociatePacketConn) WriteTo(p []byte, addr net.Addr) (n int, err error
 	if err != nil {
 		return
 	}
-	return bufio.WritePacketBuffer(c.NetPacketConn, buffer, c.remoteAddr)
+	return c.conn.Write(buffer.Bytes())
+}
+
+func (c *AssociatePacketConn) ReadPacket(buffer *buf.Buffer) (destination M.Socksaddr, err error) {
+	err = c.conn.ReadBuffer(buffer)
+	if err != nil {
+		return
+	}
+	if buffer.Len() < 3 {
+		return M.Socksaddr{}, ErrInvalidPacket
+	}
+	buffer.Advance(3)
+	destination, err = M.SocksaddrSerializer.ReadAddrPort(buffer)
+	if err != nil {
+		return
+	}
+	c.remoteAddr = destination
+	return destination.Unwrap(), nil
+}
+
+func (c *AssociatePacketConn) WritePacket(buffer *buf.Buffer, destination M.Socksaddr) error {
+	header := buf.With(buffer.ExtendHeader(3 + M.SocksaddrSerializer.AddrPortLen(destination)))
+	common.Must(header.WriteZeroN(3))
+	err := M.SocksaddrSerializer.WriteAddrPort(header, destination)
+	if err != nil {
+		return err
+	}
+	return c.conn.WriteBuffer(buffer)
 }
 
 func (c *AssociatePacketConn) Read(b []byte) (n int, err error) {
@@ -94,35 +108,12 @@ func (c *AssociatePacketConn) Write(b []byte) (n int, err error) {
 	return c.WriteTo(b, c.remoteAddr)
 }
 
-func (c *AssociatePacketConn) ReadPacket(buffer *buf.Buffer) (destination M.Socksaddr, err error) {
+func (c *AssociatePacketConn) RemoteAddr() net.Addr {
-	destination, err = c.NetPacketConn.ReadPacket(buffer)
+	return c.remoteAddr.UDPAddr()
-	if err != nil {
-		return M.Socksaddr{}, err
-	}
-	if buffer.Len() < 3 {
-		return M.Socksaddr{}, ErrInvalidPacket
-	}
-	c.remoteAddr = destination
-	buffer.Advance(3)
-	destination, err = M.SocksaddrSerializer.ReadAddrPort(buffer)
-	if err != nil {
-		return
-	}
-	return destination.Unwrap(), nil
-}
-
-func (c *AssociatePacketConn) WritePacket(buffer *buf.Buffer, destination M.Socksaddr) error {
-	header := buf.With(buffer.ExtendHeader(3 + M.SocksaddrSerializer.AddrPortLen(destination)))
-	common.Must(header.WriteZeroN(3))
-	err := M.SocksaddrSerializer.WriteAddrPort(header, destination)
-	if err != nil {
-		return err
-	}
-	return common.Error(bufio.WritePacketBuffer(c.NetPacketConn, buffer, c.remoteAddr))
 }
 
 func (c *AssociatePacketConn) Upstream() any {
-	return c.NetPacketConn
+	return c.conn
 }
 
 func (c *AssociatePacketConn) FrontHeadroom() int {
@@ -131,7 +122,7 @@ func (c *AssociatePacketConn) FrontHeadroom() int {
 
 func (c *AssociatePacketConn) Close() error {
 	return common.Close(
-		c.NetPacketConn,
+		c.conn,
 		c.underlying,
 	)
 }

protocol/socks/packet_vectorised.go

@@ -17,21 +17,11 @@ type VectorisedAssociatePacketConn struct {
 	N.VectorisedPacketWriter
 }
 
-func NewVectorisedAssociatePacketConn(conn net.PacketConn, writer N.VectorisedPacketWriter, remoteAddr M.Socksaddr, underlying net.Conn) *VectorisedAssociatePacketConn {
-	return &VectorisedAssociatePacketConn{
-		AssociatePacketConn{
-			NetPacketConn: bufio.NewPacketConn(conn),
-			remoteAddr:    remoteAddr,
-			underlying:    underlying,
-		},
-		writer,
-	}
-}
-
 func NewVectorisedAssociateConn(conn net.Conn, writer N.VectorisedWriter, remoteAddr M.Socksaddr, underlying net.Conn) *VectorisedAssociatePacketConn {
 	return &VectorisedAssociatePacketConn{
 		AssociatePacketConn{
-			NetPacketConn: bufio.NewUnbindPacketConn(conn),
+			AbstractConn: conn,
+			conn:         bufio.NewExtendedConn(conn),
 			remoteAddr:   remoteAddr,
 			underlying:   underlying,
 		},

protocol/socks/packet_wait.go

@@ -10,7 +10,7 @@ import (
 var _ N.PacketReadWaitCreator = (*AssociatePacketConn)(nil)
 
 func (c *AssociatePacketConn) CreateReadWaiter() (N.PacketReadWaiter, bool) {
-	readWaiter, isReadWaiter := bufio.CreatePacketReadWaiter(c.NetPacketConn)
+	readWaiter, isReadWaiter := bufio.CreateReadWaiter(c.conn)
 	if !isReadWaiter {
 		return nil, false
 	}
@@ -21,7 +21,7 @@ var _ N.PacketReadWaiter = (*AssociatePacketReadWaiter)(nil)
 
 type AssociatePacketReadWaiter struct {
 	conn       *AssociatePacketConn
-	readWaiter N.PacketReadWaiter
+	readWaiter N.ReadWaiter
 }
 
 func (w *AssociatePacketReadWaiter) InitializeReadWaiter(options N.ReadWaitOptions) (needCopy bool) {
@@ -29,7 +29,7 @@ func (w *AssociatePacketReadWaiter) InitializeReadWaiter(options N.ReadWaitOptio
 }
 
 func (w *AssociatePacketReadWaiter) WaitReadPacket() (buffer *buf.Buffer, destination M.Socksaddr, err error) {
-	buffer, destination, err = w.readWaiter.WaitReadPacket()
+	buffer, err = w.readWaiter.WaitReadBuffer()
 	if err != nil {
 		return
 	}
@@ -37,12 +37,12 @@ func (w *AssociatePacketReadWaiter) WaitReadPacket() (buffer *buf.Buffer, destin
 		buffer.Release()
 		return nil, M.Socksaddr{}, ErrInvalidPacket
 	}
-	w.conn.remoteAddr = destination
 	buffer.Advance(3)
 	destination, err = M.SocksaddrSerializer.ReadAddrPort(buffer)
 	if err != nil {
 		buffer.Release()
-		return nil, M.Socksaddr{}, err
+		return
 	}
+	w.conn.remoteAddr = destination
 	return
 }