基于透明Web Cache的访问控制系统设计与实现

【作者】 许艳美；

【导师】 肖宗水；

【作者基本信息】 山东大学 ， 计算机应用技术， 2005， 硕士

【摘要】 本文主要介绍了以缓存服务器为基础,结合相关路由器的WCCP技术,建构透明Web Cache的系统设计方案,以及在透明Web Cache基础上实现基于URL的访问控制的方法。该设计方案一方面提供Web数据的缓存功能,有效降低网络流量,提高网络使用效率;更重要的是,这样的系统架构,可通过对用户访问的URL进行控制,实现灵活高效的访问控制策略,以期达到对互联网上不良内容的访问控制。 该设计遵循了不改变网络拓扑结构、不改变用户的网络使用模式等透明性原则;充分利用了互联网开放源码的优越性,在Linux系统环境下对WCCP协议、GRE协议、Squid缓存引擎及其插件接口技术进行了应用研究,并以Squid缓存服务器作为访问控制的基础设施,研究了其工作机理和存在的不足,根据Squid的plugin接口标准,实现了自己的高效重定向器插件,提高了在大容量、高负载下的URL匹配效率。所以本文所介绍的基于透明Web Cache的用户访问控制系统的设计与实现具有很高的研究和应用价值。 文章中首先介绍了关于网络缓存(Web Cache)的一些基本概念和原理,并简单介绍了一下其发展过程。然后主要介绍了透明Web Cache的网络架构设计,以及在此基础上基于黑名单的用户访问控制的设计与实现。本设计和实现主要包括以下几个主要部分:1、透明Web Cache基础网络架构的设计与实现;2、Squid缓存引擎的工作机理及其插件接口标准研究;3、基于黑名单的用户访问控制重定向器插件的设计与实现。其中透明Web Cache基础网络架构采用Linux操作系统和著名的Squid缓存引擎,配合支持Wccp协议的路由器,实现缓存流量的透明重定向;Squid是Linux下一个高性能的代理缓存服务器软件,除了支持HTTP、FTP、gopher、WAIS通讯协议的代理高速缓存之外,本身还做网域名称的高速缓存用以加快网址及其IP地址的转换。它由一个主要的服务程序Squid,一个DNS查询程序dnsserver,几个重写请求和执行认证的程序,以及几个管理工具组成;基于黑名单的用户访问控制功能的实现,则采用接插件技术,做成Squid缓存引擎的一个插件,对Squid进行功能扩充和加强。它主要包括用户管理、黑名单访问控制、日志管理、黑名单数据更新和Cache挖掘等功能。 最后,总结了当前该种网络架构技术中所面临的主要发展障碍,探讨了解决更多还原

【Abstract】 This article mainly introduces the project based on cache server and WCCP technology of constructing the transparent Web Cache system architecture and depend on which implementing access control based on cache server and WCCP technology using URL. One side, this project provides the caching function of Web data, which efficiently reduces network flow and improves effiency. What is more important, owe to this kind of system architecture, the URL users access can be controlled so that the content on the Internet which is not good can be controlled depend on the flexible and efficient access control policy.This design follows the transparent principle that not to change the network topological and the network using mode of users, makes good use of the advantage of the open source technology, researches the protocol such as WCCP , GRE and Squid cache engine with its plugin technology on linux environment. Also, using Squid cache server as the access control infrastructure, on the base of understanding its working theory and disadvantage this research implements the efficient redirect plugin of its own depends on the standard of Squid plugin interface to improve the URL matching efficiency on the condition of high capacity and load. So that, the design and implement of URL access control system based on transparent Web Cache this article introduces is of high value to be research and applicated.This article first introduces several basic concepts and principles on Web Cache and its developing course, then mainly about the network architecture design of transparent Web Cache, and based on which the design and implement of user access control. This project basically includes several parts below: 1. the design and implement of transparent Web Cache network architecture ;2. the working principle of Squid cache engine and the research to its plugin interface standard; 3. the design and implementof user access control redirect plugin. In which the transparent Web Cache basic network architecture is working on linux operating system and Squid cache engine, with router which sustain WCCP protocol to implement the transparent redirect of cache flow; Squid is a efficient proxy cache server software on linux, besides working as a proxy cache which supports HTTP FTP gopher WAIS communication protocol, it can be used as the DNS cache to quicken the transform between network address and its IP address. Its consists of a main service program Squid a DNS query program dnsserver several rewriting request and certificating programs and some manage tools. The implement of user access control based on blacklist works as a plugin to Squid cache engine to extend and enhance the function of Squid, which is mainly about user management blacklist access control log record and alert system blacklist maintenance and cache digging and so on.Finally , this article summarizes the developing obstacles on this network architecture, discusses the ways to solving this problems, points out the research aspect and develop trend to guide the research in the future.更多还原