Improve udp timeout

common/canceler/packet.go

@@ -0,0 +1,41 @@
+package canceler
+
+import (
+	"context"
+	"time"
+
+	"github.com/sagernet/sing/common/buf"
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+)
+
+type PacketConn struct {
+	N.PacketConn
+	instance *Instance
+}
+
+func NewPacketConn(ctx context.Context, conn N.PacketConn, timeout time.Duration) (context.Context, N.PacketConn) {
+	ctx, cancel := context.WithCancel(ctx)
+	instance := New(ctx, cancel, timeout)
+	return ctx, &PacketConn{conn, instance}
+}
+
+func (c *PacketConn) ReadPacket(buffer *buf.Buffer) (destination M.Socksaddr, err error) {
+	destination, err = c.PacketConn.ReadPacket(buffer)
+	if err == nil {
+		c.instance.Update()
+	}
+	return
+}
+
+func (c *PacketConn) WritePacket(buffer *buf.Buffer, destination M.Socksaddr) error {
+	err := c.PacketConn.WritePacket(buffer, destination)
+	if err == nil {
+		c.instance.Update()
+	}
+	return err
+}
+
+func (c *PacketConn) Upstream() any {
+	return c.PacketConn
+}