在流量转发模块中增加DEFER数据的识别功能，避免DEFER的数据重复镜像。

* 原实现没有其他插件DEFER数据的情况，导致其他插件执行DEFER动作时重复镜像被DEFER的数据；
* 现修正，在数据入口处读取本次回调的流OFFSET值，当数据被DEFER时，仅发送本次调用增加的数据。

plugin/business/traffic-mirror/src/entry.cpp

@@ -11,6 +11,11 @@ struct traffic_mirror_me
 {
     struct profile_table_ex_data * profile_ex_data;
     struct traffic_mirror_rebuild * rebuild_ctx;
+
+    /* Make the DEFER data not to mirror twice
+     * TODO: the size of (size_t) is enough for a tcp stream offset ? */
+	size_t downstream_rx_offset_mirrored;
+	size_t upstream_tx_offset_mirrored;
 };
 
 struct traffic_mirror_instance __g_traffic_mirror_instance;
@@ -635,8 +640,60 @@ enum tfe_stream_action traffic_mirror_on_data_cb(const struct tfe_stream * strea
     enum tfe_conn_dir dir, const unsigned char * data, size_t len, void ** pme)
 {
     struct traffic_mirror_me * me = (struct traffic_mirror_me *)(*pme);
-    traffic_mirror_rebuild_data(me->rebuild_ctx, thread_id, (const char *) data, (size_t) len, dir);
+
+    /* Rx offset of this callback */
+    size_t rx_offset_this_time;
+    size_t rx_offset_mirrored;
+	enum tfe_stream_info rx_offset_type;
+
+	/* Need to mirrored data */
+	const unsigned char * ptr_data_need_to_mirrored;
+	size_t sz_data_need_to_mirrored = 0;
+
+	if (dir == CONN_DIR_DOWNSTREAM)
+	{
+		rx_offset_type = INFO_FROM_DOWNSTREAM_RX_OFFSET;
+		rx_offset_mirrored = me->downstream_rx_offset_mirrored;
+	}
+	else
+	{
+		rx_offset_type = INFO_FROM_UPSTREAM_RX_OFFSET;
+		rx_offset_mirrored = me->upstream_tx_offset_mirrored;
+	}
+
+	/* Get the offset of this callback */
+    int ret = tfe_stream_info_get(stream, rx_offset_type, &rx_offset_this_time, sizeof(rx_offset_this_time));
+    if (unlikely(ret < 0))
+	{
+		TFE_STREAM_LOG_ERROR(stream, "Failed at fetch rx offset, detached.");
+		goto errout;
+	}
+
+	/* Mirrored offset must be larger than rx_offset,
+	 * Otherwise, there is a hole in data stream */
+	assert(rx_offset_mirrored >= rx_offset_this_time);
+	assert(rx_offset_this_time + len >= rx_offset_mirrored);
+
+	sz_data_need_to_mirrored = len - (rx_offset_mirrored - rx_offset_this_time);
+	ptr_data_need_to_mirrored = data + (len - sz_data_need_to_mirrored);
+
+	/* Don't need to mirrored, the data has been mirrored in DEFER state */
+	if (sz_data_need_to_mirrored == 0)
+		goto out;
+
+	/* Update the mirrored offset */
+	if (dir == CONN_DIR_DOWNSTREAM)	me->downstream_rx_offset_mirrored += sz_data_need_to_mirrored;
+	else me->upstream_tx_offset_mirrored += sz_data_need_to_mirrored;
+
+    traffic_mirror_rebuild_data(me->rebuild_ctx, thread_id, (const char *) ptr_data_need_to_mirrored,
+    	(size_t) sz_data_need_to_mirrored, dir);
+
+out:
     return ACTION_FORWARD_DATA;
+
+errout:
+	tfe_stream_detach(stream);
+	return ACTION_FORWARD_DATA;
 }
 
 void traffic_mirror_on_close_cb(const struct tfe_stream * stream, unsigned int thread_id,