基于嵌入式Linux硬件防火墙的设计与实现

文章给出了利用Linux实现硬件防火墙的一种设计方案。介绍了基于Linux2．4内核的防火墙Netfilter框架原理，构建了该嵌入式防火墙系统的软硬件结构。然后讨论了如何在防火墙机和管理员机两端开发远程配置管理软件系统。最后给出了关键功能模块的实现方法。测试结果证明该方案是可行的。     

嵌入式Linux防火墙的设计与实现

针对嵌入武Linux防火墙进行设计并加以实现及测试.首先,提出了基于ARM处理器的嵌入式Linux防火墙的体系架构,给出了Linux一种内核裁剪定制的方案；接着,针对Netfilter/Iptables在大数量规则集下性能低下的问题,提出了Iptables结合NF-hipac、Ipset使用的解决方案,并成功实现了移植...     

基于Netfilter框架和IP Queue机制的轻量级网络防火墙实现

一般而言,要在Linux下开发防火墙的程序,需要对内核协议栈有深入的理解,并掌握内核协议栈代码的细节。这对普通开发者是非常有难度的。Netfilter是一个支持数据报过滤、数据报处理、NAT等功能的内核子系统框架。以Linux 2.6内核为基础。IP Queue机制是Linux内核在Netfilter框架的基础上提供的,是应用层上的机制,通过NetLink和内核进行交互,这使得开发一些用户态的防火墙应用成为可能。在此基础上,同时实现了一种基于Netfilter框架和IP Queue机制的轻量级防火墙。通过对比测试表明,由于设计清晰的模块架构、较强的可扩展性,本文实现的轻量级防火墙能够很好地达到实际要求,容易开发出更专业防火墙程序。     

网络风暴冲击下的流量调控平台设计与实现

网络风暴冲击下的网络结构存在较高的差异性,并且外部环境存在较高的波动性,使得传统采用异构网络协作的网络流量调控方法存在控制效率低和失衡的问题。因此,设计基于Linux防火墙的嵌入式网络流量控制系统,其是基于Linux内核Netfilter框架的流量控制系统。系统将μClinux当成操作系统的嵌入式系统,其塑造在Netfilter防火墙框架上,由内核功能模块、虚拟部件以及用户配置工具构成。内核功能模块在Netfilter框架的钩子挂载点处注册处理函数,完成网络数据包的控制,实现网络流量的调控。虚拟部件实现内核空间同用户空间配置数据的传递,确保用户采用配置工具对流量调控系统的行为进行管理。用户通过用户配置工具将待控制的主机/子网信息反馈到流量调控系统中。实验结果表明,所设计系统可实现网络风暴冲击下的网络流量的平稳控制,并且具有较高的控制效率和鲁棒性。     

基于Web管理的嵌入式防火墙设计

在简单的介绍了Linux下的netfilter/iptables防火墙机制的基础上,重点阐述了如何在PPC860开发板上实现一个独立的、可以通过Web方式管理的防火墙系统.在设计基于Web管理的嵌入式防火墙过程中,主要技术有:netfilter/iptables防火墙管理程序的移植;WBM的实现;嵌入式防火墙独立性设计等.测试结果证明:该嵌入式防火墙系统Web管理简单灵活.系统安全稳定.     

敏感网站过滤系统的研究与设计

针对Linux系统的Netfilter框架在IP包过滤和连接跟踪方面的不足,综合考虑家庭网关对含有敏感词的网站进行过滤时的特定需求,设计一款针对家庭用户的对含有敏感词的网站进行过滤的防火墙.同时对Linux的Netfilter框架进行简要的阐述,提出它在该款防火墙中存在的不足,针对不足提出一种有效的设计方案,并分析了新方案的改进内容.     

集成防火墙功能的VPN网关设计

论文应用Linux内核的Netfilter机制,针对网关的特点,对IPSec协议族进行了简化,设计实现了IPSec模块和防火墙模块,并将二者整合到Linux内核的网络部分。     

基于Netfilter和属性证书的网络设备身份认证

本文提出了一种基于Netfilter/Iptables和属性证书的网络设备身份认证系统,实现对访问安全域设备的身份认证。系统利用Linux的Netfilter防火墙和PMI体系及属性证书,实现网络设备的身份和权限的双项认证,并利用Netfilter的连接跟踪机制对已建立的网络连接进行实时的监测,从而进一步细化了数据访问的安全粒度,大大增强了网络的安全性。     

基于嵌入式Linux的3G无线视频终端的设计与实现

基于嵌入式系统开发以及3G相关技术,采用ARM+Linux作为软硬件开发平台,充分利用了ARM以及Linux系统丰富的软硬件资源,设计并实现了一个基于嵌入式Linux的3G无线视频终端。在软件设计上,采用了Linux的Netfilter架构与socket结合的方法,引入内核缓冲机制,达到了将数据包获取功能由用户态转入内核态,实现了数据包在Linux内核态的获取及高效转发,并且解决了3G模块因拨号延迟与视频服务器产生速率不匹配所造成的数据丢包问题,同时在嵌入式Linux下为3G模块开发了驱动。     

开源软件推动嵌入式实时系统

Linux是当前非常流行的操作系统,在嵌入式系统中占有重要的位置.虽然Linux采用了许多技术来提高系统的运行和反应速度,但它在本质上并不是一个实时操作系统,应用在嵌入式环境时必然会碰到内核不可抢占、进程调度、时钟等诸多问题.但是Linux本身的优势决定了Linux经过改造后仍然适合嵌入式环境,将Linux经过改造,使其能运行于嵌入式系统,是目前操作系统领域中的一个研究热点.RTLinux就是Linux实时改造非常成功的一例.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first