安全存储系统中TCP流还原加速策略研究

Research on TCP stream reassembly acceleration strategy in secure storage system

在TCP状态中,当连接两端非正常关闭时,出现的CLOSING状态会增加许多不必要的等待时间.为了提高安全存储系统中TCP流还原的效率,结合Snort中Splay树排序算法从TCP状态机、定时器和流还原算法3个方面对TCP流还原加以改进.提出约去CLOSING状态的同时删去时间等待定时器,并在流还原中采用Hash表对大量TCP流进行管理,采用Splay树对属于同一条流的分段进行排序.实验表明,改进后TCP流还原的效率有了明显提升.

In the TCP states,when the connection is closed abnormally,the CLOSING state will cause much unnecessary waiting time.In order to improve the efficiency of TCP stream reassembly in the secure storage system,combining with the Splay tree sorting algorithm in Snort,the TCP stream reassembly is improved from three aspects of TCP state machine,TCP timer and stream reassembly algorithm.It is proposed that reducing CLOSING state as well as deleting the time-waiting timer,Hash table is used in the stream reassembly algorithm to manage a large number of TCP flows,and Splay tree is used to sort the TCP segments which belong to the same flow.The experimental results prove that the efficiency of TCP stream reassembly is significantly improved.