chore: better packet deadline

common/net/deadline/packet_enhance.go

@@ -0,0 +1,73 @@
+package deadline
+
+import (
+	"net"
+	"os"
+
+	"github.com/Dreamacro/clash/common/net/packet"
+)
+
+type EnhancePacketConn struct {
+	*NetPacketConn
+	enhancePacketConn
+}
+
+var _ packet.EnhancePacketConn = (*EnhancePacketConn)(nil)
+
+func NewEnhancePacketConn(pc packet.EnhancePacketConn) packet.EnhancePacketConn {
+	return NewNetPacketConn(pc).(packet.EnhancePacketConn)
+}
+
+type enhanceReadResult struct {
+	put func()
+}
+
+type enhancePacketConn struct {
+	netPacketConn     *NetPacketConn
+	enhancePacketConn packet.EnhancePacketConn
+}
+
+func (c *enhancePacketConn) WaitReadFrom() (data []byte, put func(), addr net.Addr, err error) {
+	select {
+	case result := <-c.netPacketConn.resultCh:
+		if result != nil {
+			data = result.data
+			put = result.put
+			addr = result.addr
+			err = result.err
+			c.netPacketConn.resultCh <- nil // finish cache read
+			return
+		} else {
+			c.netPacketConn.resultCh <- nil
+			break
+		}
+	case <-c.netPacketConn.pipeDeadline.wait():
+		return nil, nil, nil, os.ErrDeadlineExceeded
+	}
+
+	if c.netPacketConn.disablePipe.Load() {
+		return c.enhancePacketConn.WaitReadFrom()
+	} else if c.netPacketConn.deadline.Load().IsZero() {
+		c.netPacketConn.inRead.Store(true)
+		defer c.netPacketConn.inRead.Store(false)
+		data, put, addr, err = c.enhancePacketConn.WaitReadFrom()
+		return
+	}
+
+	<-c.netPacketConn.resultCh
+	go c.pipeWaitReadFrom()
+
+	return c.WaitReadFrom()
+}
+
+func (c *enhancePacketConn) pipeWaitReadFrom() {
+	data, put, addr, err := c.enhancePacketConn.WaitReadFrom()
+	c.netPacketConn.resultCh <- &readResult{
+		data: data,
+		enhanceReadResult: enhanceReadResult{
+			put: put,
+		},
+		addr: addr,
+		err:  err,
+	}
+}