fix dtls connection

internal/util/dtls/conn.go

@@ -0,0 +1,73 @@
+package dtls
+
+import (
+	"bytes"
+	"net"
+
+	"github.com/go-gost/core/common/bufpool"
+)
+
+type dtlsConn struct {
+	net.Conn
+	rbuf       bytes.Buffer
+	bufferSize int
+}
+
+func Conn(c net.Conn, bufferSize int) net.Conn {
+	return &dtlsConn{
+		Conn:       c,
+		bufferSize: bufferSize,
+	}
+}
+
+func (c *dtlsConn) Read(p []byte) (n int, err error) {
+	/*
+		defer func() {
+			logger.Default().Debugf("dtls: read data %d/%d, %v", n, len(p), err)
+		}()
+	*/
+
+	if c.rbuf.Len() > 0 {
+		return c.rbuf.Read(p)
+	}
+
+	bufferSize := c.bufferSize
+	if len(p) >= bufferSize {
+		return c.Conn.Read(p)
+	}
+
+	buf := bufpool.Get(bufferSize)
+	defer bufpool.Put(buf)
+
+	nn, err := c.Conn.Read(*buf)
+	if err != nil {
+		return 0, err
+	}
+
+	n = copy(p, (*buf)[:nn])
+	c.rbuf.Write((*buf)[n:nn])
+
+	return
+}
+
+func (c *dtlsConn) Write(p []byte) (n int, err error) {
+	/*
+		defer func() {
+			logger.Default().Debugf("dtls: write data %d, %v", n, err)
+		}()
+	*/
+
+	for len(p) > 0 {
+		nn := c.bufferSize
+		if nn > len(p) {
+			nn = len(p)
+		}
+		nn, err = c.Conn.Write(p[:nn])
+		n += nn
+		if err != nil {
+			return
+		}
+		p = p[nn:]
+	}
+	return
+}