A STUDY ON FALSE CHANNEL CONDITION REPORTING ATTACKS IN WIRELESS NETWORKS
By
A
PROJECT REPORT
Submitted to the Department of Computer Science & Engineering in the FACULTY OF ENGINEERING & TECHNOLOGY
In partial fulfillment of the requirements for the award of the degree
Of
MASTER OF TECHNOLOGY
IN
COMPUTER SCIENCE & ENGINEERING
APRIL 2015
BONAFIDE CERTIFICATE
Certified that this project report titled “A STUDY ON FALSE CHANNEL CONDITION REPORTING ATTACKS IN WIRELESS NETWORKS” is the bonafide work of Mr. _____________Who carried out the research under my supervision Certified further, that to the best of my knowledge the work reported herein does not form part of any other project report or dissertation on the basis of which a degree or award was conferred on an earlier occasion on this or any other candidate.
Signature of the Guide Signature of the H.O.D
Name Name
CHAPTER 1
Wireless networking protocols are increasingly being designed to exploit a user’s measured channel condition; we call such protocols channel-aware. Each user reports the measured channel condition to a manager of wireless resources and a channel-aware protocol uses these reports to determine how resources are allocated to users. In a channel-aware protocol, each user’s reported channel condition affects the performance of every other user. The deployment of channel-aware protocols increases the risks posed by false channel-condition feedback.
We study
what happens in the presence of an attacker that falsely reports its channel
condition. We perform case studies on channel-aware network protocols to
understand how an attack can use false feedback and how much the attack can
affect network performance. The results of the case studies show that we need a
secure channel condition estimation algorithm to fundamentally defend against
the channel-condition misreporting attack. We design such an algorithm and evaluate
our algorithm through analysis and simulation. Our evaluation quantifies the
effect of our algorithm on system performance as well as the security and the
performance of our algorithm.
Many protocols in modern wireless networks treat a link’s channel condition information as a protocol input parameter; we call such protocols channel-aware. Examples include cooperative relaying network architectures, efficient ad hoc network routing metrics, and opportunistic schedulers. While work on channel-aware protocols has mainly focused on how channel condition information can be used to more efficiently utilize wireless resources, security aspects of channel-aware protocols have only recently been studied. These works on security of channel-aware protocols revealed new threats in specific network environments by simulation or measurement.
However, understanding the effect of
possible attacks across varied network environments is still an open area for
study. In particular, we consider the effect of a user equipment’s reporting
false channel condition. This issue is partially addressed in the work of Racic
et al. in a limited network setting.
They consider a particular scheduler in a cellular network with handover
process and propose a secure handover algorithm. In contrast, we reveal the
possible effects of false channel condition reporting in various channel-aware
network protocols and propose a primitive defense mechanism that provides
secure channel condition estimation.
Our contributions are:
• We analyze specific attack mechanisms and evaluate the effects of misreporting channel condition on various channel-aware wireless network protocols including cooperative relaying protocols, routing metrics in wireless ad-hoc network and opportunistic schedulers.
• We propose a secure channel condition estimation algorithm that can be used to construct a secure channel-aware protocol in single-hop settings.
• We analyze our algorithm in the respects of performance and security, and we perform a simulation study to understand the impact of our algorithm on system performance.
The false
channel condition reporting attack that we introduce in this paper is difficult
to identify by existing mechanisms, since our attack is mostly protocol
compliant; only the channel-condition measurement mechanism need to be
modified. Our attack can thus be performed using modified user equipment
legitimately registered to a network.
1.3 LITRATURE SURVEY
EXPLOITING AND DEFENDING OPPORTUNISTIC SCHEDULING IN CELLULAR DATA NETWORKS
PUBLICATION: R. Racic, D. Ma, H. Chen, and X. Liu, IEEE Trans. Mobile Comput., vol. 9, no. 5, pp. 609–620, May 2010.
Third Generation (3G)
cellular networks take advantage of time-varying and location-dependent channel
conditions of mobile users to provide broadband services. Under fairness and
QoS constraints, they use opportunistic scheduling to efficiently utilize the
available spectrum. Opportunistic scheduling algorithms rely on the
collaboration among all mobile users to achieve their design objectives.
However, we demonstrate that rogue cellular devices can exploit vulnerabilities
in popular opportunistic scheduling algorithms, such as Proportional Fair (PF)
and Temporal Fair (TF), to usurp the majority of time slots in 3G networks. Our
simulations show that under realistic conditions, only five rogue device per
50-user cell can capture up to 95 percent of the time slots, and can cause
2-second end-to-end interpacket transmission delay on VoIP applications for
every user in the same cell, rendering VoIP applications useless. To defend
against this attack, we propose strengthening the PF and TF schedulers and a
robust handoff scheme.
ON THE VULNERABILITY OF THE PROPORTIONAL FAIRNESS SCHEDULER TO RETRANSMISSION ATTACKS
PUBLICATION: U. Ben-Porat, A. Bremler-Barr, H. Levy, and B. Plattner, in Proc. IEEE INFOCOM, Shanghai, China, Apr. 2011, pp. 1431–1439.
Channel aware schedulers of modern
wireless networks – such as the popular Proportional Fairness Scheduler (PFS) –
improve throughput performance by exploiting channel fluctuations while
maintaining fairness among the users. In order to simplify the analysis, PFS
was introduced and vastly investigated in a model where frame losses do not
occur, which is of course not the case in practical wireless networks. Recent
studies focused on the efficiency of various implementations of PFS in a
realistic model where frame losses can occur. In this work we show that the
common straight forward adaptation of PFS to frame losses exposes the system to
a malicious attack (which can alternatively be caused by malfunctioning user
equipment) that can drastically degrade the performance of innocent users. We
analyze the factors behind the vulnerability of the system and propose a
modification of PFS designed for the frame loss model which is resilient to
such malicious attack while maintaining the fairness properties of original
PFS.
A MEASUREMENT STUDY OF SCHEDULER-BASED ATTACKS IN 3G WIRELESS NETWORKS
PUBLICATION: S. Bali, S. Machiraju, H. Zang, and V. Frost, in Proc. PAM, Berlin, Germany, 2007.
Though high-speed (3G) wide-area wireless networks
have been rapidly proliferating, little is known about the robustness and
security properties of these networks. In this paper, we make initial steps
towards understanding these properties by studying Proportional Fair (PF), the
scheduling algorithm used on the downlinks of these networks. We find that the
fairness-ensuring mechanism of PF can be easily corrupted by a malicious user
to monopolize the wireless channel thereby starving other users. Using
extensive experiments on commercial and laboratory-based CDMA networks, we
demonstrate this vulnerability and quantify the resulting performance impact.
We find that delay jitter can be increased by up to 1 second and TCP throughput
can be reduced by as much as 25−30 % by a single malicious user. Based on our
results, we argue for the need to use a more robust scheduling algorithm and
outline one such algorithm. 1
CHAPTER 2
2.0 SYSTEM ANALYSIS
2.1 EXISTING SYSTEM:
Many protocols
in modern wireless networks treat a link’s channel condition information as a
protocol input parameter; we call such protocols channel-aware. Examples
include cooperative relaying network architectures, efficient ad hoc network
routing metrics, and opportunistic schedulers. While work on channel-aware
protocols has mainly focused on how channel condition information can be used
to more efficiently utilize wireless resources, security aspects of
channel-aware protocols have only recently been studied. These works on
security of channel-aware protocols revealed new threats in specific network
environments by simulation or measurement. However, under-standing the effect
of possible attacks across varied network environments is still an open area
for study.
2.1.1 DISADVANTAGES:
2.2 PROPOSED SYSTEM:
We introduce our attack concept and perform case studies to quantize the attack effects on specific channel-aware network protocols. Depending on deployed PHY-layer technologies (e.g. OFDM), a system can utilize conditions for subchannels to perform more efficient frequency-selective scheduling. Our work can apply for this case by handling each subchannel condition information separately. However, for clarity of presentation, we consider a single channel between network participants in this paper.
We can easily implement false channel
condition reporting attack by modifying only a subcomponent to report channel
condition. This subcomponent of user equipment can be implemented in hardware
or software. One recent trend of user equipment implementation is to
increasingly move hardware part to software part for adaptable configuration of
a general hardware. The increasing software control of user equipment makes
false channel condition reporting attack an increasingly practical attack.
2.2.1 ADVANTAGES:
2.3.1 HARDWARE REQUIREMENT:
CHAPTER 3
3.0 SYSTEM DESIGN:
Data Flow Diagram / Use Case Diagram / Flow Diagram:
NOTATION:
External sources or destinations, which may be people or organizations or other entities
Here the data referenced by a process is stored and retrieved.
People, procedures or devices that produce data. The physical component is not identified.
Data moves in a specific direction from an origin to a destination. The data flow is a “packet” of data.
There are several common modeling rules when creating DFDs:
3.1 ARCHITECTURE DIAGRAM:
3.2 DATAFLOW DIAGRAM:
UML DIAGRAMS:
3.2 USE CASE DIAGRAM:
3.3 CLASS DIAGRAM:
3.4 SEQUENCE DIAGRAM:
3.5 ACTIVITY DIAGRAM:
CHAPTER 4
4.0 IMPLEMENTATION:
We performed a simulation study to evaluate the overclaiming attack’s effect on the normal users’ performance in a cooperative relaying environment. We quantifyWe use the ns-2 simulator patched with EURANE UMTS system simulator. Our simulated network consists of one base station serving four users. The base station sends 11Mbps of Constant Bit Rate (CBR) traffic to each user. There is one attacker who may falsely report its channel condition to the base station. We represent channel condition using the Channel Quality Indicator (CQI) defined in the 3GPP standard.
The same equation and block size are
used for a case study of opportunistic scheduler presented in Section 2.2.3. We
assume that one victim is close to the attacker so that when the victim
experiences poor channel condition, the victim can use the attacker as a
relaying node. The other two normal users get packets directly from the base
station and do not participate in the cooperative relaying protocol. The victim
and the two normal users honestly report their channel condition. The channel
for the attacker and two normal users uses a shadowing plus Rayleigh model of a
moving node 100m away from the base station with velocity of 3km/h. We vary the
victim’s distance to the base station from 100m to 500m to see the effect of
the victim’s channel condition on the performance degradation.
The attacker’s goal in this simulation is to reduce the victim’s throughput. The attacker can adopt two approaches. In the conservative approach, the attacker does not forward packets for the victim without falsely reporting its channel condition. In the aggressive approach, the attacker overclaims its channel condition so that the attacker can increase its probability of relaying packets for the victim.
Our simulations do not consider the overhead that an actual relaying protocol might incur in finding a new relaying node due to channel condition variation since such overhead is not related to the effect of attack. We assume that each transmission uses an orthogonal carrier so that transmissions do not interfere with each other.
Our simulations do not implement a relay
discovery protocol; rather, we compare the attacker and victim CQI, and use the
link with better CQI value to transmit to the victim. This relaying scheme is
an example; a system operator may choose a different scheme. However, the
scheme that we chose is good for exploiting increased diversity to optimize
throughput. We ran each of our simulations for 100 simulated seconds.
4.1 ALGORITHM
In this section, we evaluate the performance and the security of our algorithm. Firstly, we analyze the performance of our algorithm according to algorithm parameters. This analysis can be used for parameter design guidelines. This analysis result is compared to simulation results. Secondly, we analyze the security of our algorithm. In this analysis, we show how much a brute-force attacker can be successful in guessing the value included in a challenge according to algorithm parameters. This analysis can be used for understanding tradeoff between security and system overhead. Thirdly, we integrate our algorithm into a network simulator and evaluate the effect of our algorithm on the system performance. We show that our algorithm securely and effectively estimates channel condition through most of its parameter space.
We used identical parameters, except we replaced the static channel with various variable channel models. We measure the throughput of normal users under scheduling policies of MAX-SINR, PF and MAX-SINR with our algorithm. In MAX-SINR with our algorithm, a base station does not use reported CQI-level to determine a user with the best channel condition in a give time slot. Instead, the base station uses CQI-level estimated by our algorithm. In the case study of opportunistic scheduler, our observation was that PF scheduler prevented attackers from stealing throughput. Hence, we concluded that PF was a good candidate for defending against false channel condition reporting attack. However, our simulation results for the system performance show that MAX-SINR with our algorithm can achieve higher throughput than PF scheduler in most cases. The fact that the performance of our algorithm depends on channel characteristic affects the throughput of normal users in case of MAX-SINR with our algorithm.
4.2 MODULE DESCRIPTION:
SERVER CLIENT MODULE:
NETWORK SECURITY:
COOPERATIVE RELAYING:
EFFICIENT ROUTING METRICS:
PERFORMANCE ANALYSIS
4.3 MODULES DESCRIPTION:
SERVER CLIENT MODULE:
Client-server computing or networking is a distributed application architecture that partitions tasks or workloads between service providers (servers) and service requesters, called clients. Often clients and servers operate over a computer network on separate hardware. A server machine is a high-performance host that is running one or more server programs which share its resources with clients. A client also shares any of its resources; Clients therefore initiate communication sessions with servers which await (listen to) incoming requests.
NETWORK SECURITY:
Network-accessible
resources may be deployed in a network as surveillance and early-warning tools,
as the detection of attackers are not normally accessed for legitimate
purposes. Techniques used by the attackers that attempt to compromise these
decoy resources are studied during and after an attack to keep an eye on new exploitation techniques. Such analysis may be used
to further tighten security of the actual network being protected by the data’s.
Data forwarding can also direct an attacker’s attention away from legitimate
servers. A user encourages attackers to spend their time and energy on the
decoy server while distracting their attention from the data on the real
server. Similar to a server, a user is a network set up with intentional
vulnerabilities. Its purpose is also to invite attacks so that the attacker’s
methods can be studied and that information can be used to increase network
security.
ATTACK MODEL:
We introduce our attack concept and perform case studies to quantize the attack effects on specific channel-aware network protocols. We evaluate the effect of falsely reported channel condition under three types of channel-aware protocols: cooperative relaying protocols in hybrid networks, efficient routing metrics in wireless ad hoc networks, and opportunistic schedulers in high-speed wireless networks. For each protocol, we suggest possible attack mechanisms and quantify the effectiveness of the attack. We show that we can defend against some attacks using existing algorithms, and that other attacks require new security mechanisms. Each following case study has the same presentation format. First, we briefly explain the protocols. Then, we discuss effective attack scenarios for each protocol. Finally, we use simulations to evaluate the effect of each attack scenario.
COOPERATIVE RELAYING:
In a mobile wireless network, mobile nodes can experience different channel conditions depending on their different locations. When a node experiences a channel condition that is too poor to receive packets from a source node, a third node may have a good channel condition to both the source and the intended destination. Cooperative relaying network architectures help a node that has poor channel condition to route its packet through a node with a good channel condition, thus improving system throughput.
A cooperative relaying protocol must
distribute channel condition information for each candidate path, find the most
appropriate relay path, and provide incentives to motivate nodes to forward
packets for other nodes. Specifically, in UCAN user equipment has two wireless
adaptors, one High Data Rate (HDR) cellular interface and one IEEE 802.11
interface. The HDR interface is used for communication with a base station and
the IEEE 802.11 interface is used for peer-to-peer communication with other
user equipment in a network.
EFFICIENT ROUTING METRICS:
Routing Protocols in Ad Hoc Networks a wireless ad hoc network supports communication between nodes without need for centralized infrastructure such as base stations or access points. To deliver packets to destinations out of a source node’s transmission range, the source employs the help of intermediate nodes to forward each packet to its destination. Routing protocols in wireless ad hoc network discover routes between nodes. When there are multiple valid routes from a source to a destination, a routing protocol needs to choose among valid routes. A routing metric is a value associated to a route and represents the desirability of a route. A typical metric in the seminal routing protocols is minimum hop count. The rationale behind the metric of minimum hop count is that a route with fewer hops allows a packet to be delivered with the smaller number of transmissions.
PERFORMANCE ANALYSIS:
Our analysis assumes that the channel
condition does not change. Though this assumption does not hold in a mobile
environment, the purpose of our analysis is not to capture every detail of real
world but to verify our simulator. For the evaluation in a realistic
environment, we perform simulations with channel models considering variable
channel conditions, as described in that the challenge size and Psref (i) are
the same for different challenges for easy comparison of performance. The
equations in our analysis do not assume the same values of challenge size and Psref
(i). However, with different values of challenge size and Psref (i),
it is not easy to understand the parameters’ effect on the performance. In this
analysis, we assume that the challenges are authenticated.
CHAPTER 5
5.0 SYSTEM STUDY:
5.1 FEASIBILITY STUDY:
The feasibility of the project is analyzed in this phase and business proposal is put forth with a very general plan for the project and some cost estimates. During system analysis the feasibility study of the proposed system is to be carried out. This is to ensure that the proposed system is not a burden to the company. For feasibility analysis, some understanding of the major requirements for the system is essential.
Three key considerations involved in the feasibility analysis are
5.1.1 ECONOMICAL FEASIBILITY:
This study is carried out to check the economic impact that the system will have on the organization. The amount of fund that the company can pour into the research and development of the system is limited. The expenditures must be justified. Thus the developed system as well within the budget and this was achieved because most of the technologies used are freely available. Only the customized products had to be purchased.
This study is carried out to check the technical feasibility, that is, the technical requirements of the system. Any system developed must not have a high demand on the available technical resources. This will lead to high demands on the available technical resources. This will lead to high demands being placed on the client. The developed system must have a modest requirement, as only minimal or null changes are required for implementing this system.
5.1.3 SOCIAL FEASIBILITY:
The aspect of study is to check the level of acceptance of the system by the user. This includes the process of training the user to use the system efficiently. The user must not feel threatened by the system, instead must accept it as a necessity. The level of acceptance by the users solely depends on the methods that are employed to educate the user about the system and to make him familiar with it. His level of confidence must be raised so that he is also able to make some constructive criticism, which is welcomed, as he is the final user of the system.
5.2 SYSTEM TESTING:
Testing is a process of checking whether the developed system is working according to the original objectives and requirements. It is a set of activities that can be planned in advance and conducted systematically. Testing is vital to the success of the system. System testing makes a logical assumption that if all the parts of the system are correct, the global will be successfully achieved. In adequate testing if not testing leads to errors that may not appear even many months.
This creates two problems, the time lag
between the cause and the appearance of the problem and the effect of the
system errors on the files and records within the system. A small system error
can conceivably explode into a much larger Problem. Effective testing early in
the purpose translates directly into long term cost savings from a reduced
number of errors. Another reason for system testing is its utility, as a
user-oriented vehicle before implementation. The best programs are worthless if
it produces the correct outputs.
5.2.1 UNIT TESTING:
| Description | Expected result |
| Test for application window properties. | All the properties of the windows are to be properly aligned and displayed. |
| Test for mouse operations. | All the mouse operations like click, drag, etc. must perform the necessary operations without any exceptions. |
A program
represents the logical elements of a system. For a program to run
satisfactorily, it must compile and test data correctly and tie in properly
with other programs. Achieving an error free program is the responsibility of
the programmer. Program testing checks
for two types
of errors: syntax
and logical. Syntax error is a
program statement that violates one or more rules of the language in which it
is written. An improperly defined field dimension or omitted keywords are
common syntax errors. These errors are shown through error message generated by
the computer. For Logic errors the programmer must examine the output
carefully.
5.1.2 FUNCTIONAL TESTING:
Functional testing of an application is used to prove the application delivers correct results, using enough inputs to give an adequate level of confidence that will work correctly for all sets of inputs. The functional testing will need to prove that the application works for each client type and that personalization function work correctly.When a program is tested, the actual output is compared with the expected output. When there is a discrepancy the sequence of instructions must be traced to determine the problem. The process is facilitated by breaking the program into self-contained portions, each of which can be checked at certain key points. The idea is to compare program values against desk-calculated values to isolate the problems.
| Description | Expected result |
| Test for all modules. | All peers should communicate in the group. |
| Test for various peer in a distributed network framework as it display all users available in the group. | The result after execution should give the accurate result. |
5.1. 3 NON-FUNCTIONAL TESTING:
The Non Functional software testing encompasses a rich spectrum of testing strategies, describing the expected results for every test case. It uses symbolic analysis techniques. This testing used to check that an application will work in the operational environment. Non-functional testing includes:
5.1.4 LOAD TESTING:
An important tool for implementing system tests is a Load generator. A Load generator is essential for testing quality requirements such as performance and stress. A load can be a real load, that is, the system can be put under test to real usage by having actual telephone users connected to it. They will generate test input data for system test.
| Description | Expected result |
| It is necessary to ascertain that the application behaves correctly under loads when ‘Server busy’ response is received. | Should designate another active node as a Server. |
5.1.5 PERFORMANCE TESTING:
Performance tests are utilized in order to determine the widely defined performance of the software system such as execution time associated with various parts of the code, response time and device utilization. The intent of this testing is to identify weak points of the software system and quantify its shortcomings.
| Description | Expected result |
| This is required to assure that an application perforce adequately, having the capability to handle many peers, delivering its results in expected time and using an acceptable level of resource and it is an aspect of operational management. | Should handle large input values, and produce accurate result in a expected time. |
5.1.6 RELIABILITY TESTING:
The software reliability is the ability of a system or component to perform its required functions under stated conditions for a specified period of time and it is being ensured in this testing. Reliability can be expressed as the ability of the software to reveal defects under testing conditions, according to the specified requirements. It the portability that a software system will operate without failure under given conditions for a given time interval and it focuses on the behavior of the software element. It forms a part of the software quality control team.
| Description | Expected result |
| This is to check that the server is rugged and reliable and can handle the failure of any of the components involved in provide the application. | In case of failure of the server an alternate server should take over the job. |
5.1.7 SECURITY TESTING:
Security testing evaluates system characteristics that relate to the availability, integrity and confidentiality of the system data and services. Users/Clients should be encouraged to make sure their security needs are very clearly known at requirements time, so that the security issues can be addressed by the designers and testers.
| Description | Expected result |
| Checking that the user identification is authenticated. | In case failure it should not be connected in the framework. |
| Check whether group keys in a tree are shared by all peers. | The peers should know group key in the same group. |
5.1.8 WHITE BOX TESTING:
White box testing, sometimes called glass-box testing is a test case design method that uses the control structure of the procedural design to derive test cases. Using white box testing method, the software engineer can derive test cases. The White box testing focuses on the inner structure of the software structure to be tested.
| Description | Expected result |
| Exercise all logical decisions on their true and false sides. | All the logical decisions must be valid. |
| Execute all loops at their boundaries and within their operational bounds. | All the loops must be finite. |
| Exercise internal data structures to ensure their validity. | All the data structures must be valid. |
5.1.9 BLACK BOX TESTING:
Black box testing, also called behavioral testing, focuses on the functional requirements of the software. That is, black testing enables the software engineer to derive sets of input conditions that will fully exercise all functional requirements for a program. Black box testing is not alternative to white box techniques. Rather it is a complementary approach that is likely to uncover a different class of errors than white box methods. Black box testing attempts to find errors which focuses on inputs, outputs, and principle function of a software module. The starting point of the black box testing is either a specification or code. The contents of the box are hidden and the stimulated software should produce the desired results.
| Description | Expected result |
| To check for incorrect or missing functions. | All the functions must be valid. |
| To check for interface errors. | The entire interface must function normally. |
| To check for errors in a data structures or external data base access. | The database updation and retrieval must be done. |
| To check for initialization and termination errors. | All the functions and data structures must be initialized properly and terminated normally. |
All
the above system testing strategies are carried out in as the development,
documentation and institutionalization of the proposed goals and related
policies is essential.
CHAPTER 6
6.0 SOFTWARE DESCRIPTION:
Java technology is both a programming language and a platform.
With most programming languages, you either compile or interpret a program so that you can run it on your computer. The Java programming language is unusual in that a program is both compiled and interpreted. With the compiler, first you translate a program into an intermediate language called Java byte codes —the platform-independent codes interpreted by the interpreter on the Java platform. The interpreter parses and runs each Java byte code instruction on the computer. Compilation happens just once; interpretation occurs each time the program is executed. The following figure illustrates how this works.
You can think of Java byte codes as the machine code instructions for the Java Virtual Machine (Java VM). Every Java interpreter, whether it’s a development tool or a Web browser that can run applets, is an implementation of the Java VM. Java byte codes help make “write once, run anywhere” possible. You can compile your program into byte codes on any platform that has a Java compiler. The byte codes can then be run on any implementation of the Java VM. That means that as long as a computer has a Java VM, the same program written in the Java programming language can run on Windows 2000, a Solaris workstation, or on an iMac.
A platform is the hardware or software environment in which a program runs. We’ve already mentioned some of the most popular platforms like Windows 2000, Linux, Solaris, and MacOS. Most platforms can be described as a combination of the operating system and hardware. The Java platform differs from most other platforms in that it’s a software-only platform that runs on top of other hardware-based platforms.
The Java platform has two components:
You’ve already been introduced to the Java VM. It’s the base for the Java platform and is ported onto various hardware-based platforms.
The Java API is a large collection of ready-made software components that provide many useful capabilities, such as graphical user interface (GUI) widgets. The Java API is grouped into libraries of related classes and interfaces; these libraries are known as packages. The next section, What Can Java Technology Do? Highlights what functionality some of the packages in the Java API provide.
The following figure depicts a program that’s running on the Java platform. As the figure shows, the Java API and the virtual machine insulate the program from the hardware.
Native code is code that after you compile it, the compiled code runs on a specific hardware platform. As a platform-independent environment, the Java platform can be a bit slower than native code. However, smart compilers, well-tuned interpreters, and just-in-time byte code compilers can bring performance close to that of native code without threatening portability.
The most common types of programs written in the Java programming language are applets and applications. If you’ve surfed the Web, you’re probably already familiar with applets. An applet is a program that adheres to certain conventions that allow it to run within a Java-enabled browser.
However, the Java programming language is not just for writing cute, entertaining applets for the Web. The general-purpose, high-level Java programming language is also a powerful software platform. Using the generous API, you can write many types of programs.
An application is a standalone program that runs directly on the Java platform. A special kind of application known as a server serves and supports clients on a network. Examples of servers are Web servers, proxy servers, mail servers, and print servers. Another specialized program is a servlet.
A servlet can almost be thought of as an applet that runs on the server side. Java Servlets are a popular choice for building interactive web applications, replacing the use of CGI scripts. Servlets are similar to applets in that they are runtime extensions of applications. Instead of working in browsers, though, servlets run within Java Web servers, configuring or tailoring the server.
How does the API support all these kinds of programs? It does so with packages of software components that provides a wide range of functionality. Every full implementation of the Java platform gives you the following features:
The Java platform also has APIs for 2D and 3D graphics, accessibility, servers, collaboration, telephony, speech, animation, and more. The following figure depicts what is included in the Java 2 SDK.
We can’t promise you fame, fortune, or even a job if you learn the Java programming language. Still, it is likely to make your programs better and requires less effort than other languages. We believe that Java technology will help you do the following:
Microsoft Open Database Connectivity (ODBC) is a standard programming interface for application developers and database systems providers. Before ODBC became a de facto standard for Windows programs to interface with database systems, programmers had to use proprietary languages for each database they wanted to connect to. Now, ODBC has made the choice of the database system almost irrelevant from a coding perspective, which is as it should be. Application developers have much more important things to worry about than the syntax that is needed to port their program from one database to another when business needs suddenly change.
Through the ODBC Administrator in Control Panel, you can specify the particular database that is associated with a data source that an ODBC application program is written to use. Think of an ODBC data source as a door with a name on it. Each door will lead you to a particular database. For example, the data source named Sales Figures might be a SQL Server database, whereas the Accounts Payable data source could refer to an Access database. The physical database referred to by a data source can reside anywhere on the LAN.
The ODBC system files are not installed on your system by Windows 95. Rather, they are installed when you setup a separate database application, such as SQL Server Client or Visual Basic 4.0. When the ODBC icon is installed in Control Panel, it uses a file called ODBCINST.DLL. It is also possible to administer your ODBC data sources through a stand-alone program called ODBCADM.EXE. There is a 16-bit and a 32-bit version of this program and each maintains a separate list of ODBC data sources.
From a programming perspective, the beauty of ODBC is that the application can be written to use the same set of function calls to interface with any data source, regardless of the database vendor. The source code of the application doesn’t change whether it talks to Oracle or SQL Server. We only mention these two as an example. There are ODBC drivers available for several dozen popular database systems. Even Excel spreadsheets and plain text files can be turned into data sources. The operating system uses the Registry information written by ODBC Administrator to determine which low-level ODBC drivers are needed to talk to the data source (such as the interface to Oracle or SQL Server). The loading of the ODBC drivers is transparent to the ODBC application program. In a client/server environment, the ODBC API even handles many of the network issues for the application programmer.
The advantages
of this scheme are so numerous that you are probably thinking there must be
some catch. The only disadvantage of ODBC is that it isn’t as efficient as
talking directly to the native database interface. ODBC has had many detractors
make the charge that it is too slow. Microsoft has always claimed that the
critical factor in performance is the quality of the driver software that is
used. In our humble opinion, this is true. The availability of good ODBC
drivers has improved a great deal recently. And anyway, the criticism about
performance is somewhat analogous to those who said that compilers would never
match the speed of pure assembly language. Maybe not, but the compiler (or
ODBC) gives you the opportunity to write cleaner programs, which means you
finish sooner. Meanwhile, computers get faster every year.
6.6 JDBC:
In an effort to set an independent database standard API for Java; Sun Microsystems developed Java Database Connectivity, or JDBC. JDBC offers a generic SQL database access mechanism that provides a consistent interface to a variety of RDBMSs. This consistent interface is achieved through the use of “plug-in” database connectivity modules, or drivers. If a database vendor wishes to have JDBC support, he or she must provide the driver for each platform that the database and Java run on.
To gain a wider acceptance of JDBC, Sun based JDBC’s framework on ODBC. As you discovered earlier in this chapter, ODBC has widespread support on a variety of platforms. Basing JDBC on ODBC will allow vendors to bring JDBC drivers to market much faster than developing a completely new connectivity solution.
JDBC was announced in March of 1996. It was released for a 90 day public review that ended June 8, 1996. Because of user input, the final JDBC v1.0 specification was released soon after.
The remainder of this section will cover enough information about JDBC for you to know what it is about and how to use it effectively. This is by no means a complete overview of JDBC. That would fill an entire book.
Few software packages are designed without goals in mind. JDBC is one that, because of its many goals, drove the development of the API. These goals, in conjunction with early reviewer feedback, have finalized the JDBC class library into a solid framework for building database applications in Java.
The goals that were set for JDBC are important. They will give you some insight as to why certain classes and functionalities behave the way they do. The eight design goals for JDBC are as follows:
SQL Level API
The designers felt that their main goal was to define a SQL interface for Java. Although not the lowest database interface level possible, it is at a low enough level for higher-level tools and APIs to be created. Conversely, it is at a high enough level for application programmers to use it confidently. Attaining this goal allows for future tool vendors to “generate” JDBC code and to hide many of JDBC’s complexities from the end user.
SQL Conformance
SQL syntax varies as you move from database vendor to database vendor. In an effort to support a wide variety of vendors, JDBC will allow any query statement to be passed through it to the underlying database driver. This allows the connectivity module to handle non-standard functionality in a manner that is suitable for its users.
JDBC must be implemental on top of common database interfaces
The JDBC SQL API must “sit” on top of other common SQL level APIs. This goal allows JDBC to use existing ODBC level drivers by the use of a software interface. This interface would translate JDBC calls to ODBC and vice versa.
Because of Java’s acceptance in the user community thus far, the designers feel that they should not stray from the current design of the core Java system.
This goal probably appears in all software design goal listings. JDBC is no exception. Sun felt that the design of JDBC should be very simple, allowing for only one method of completing a task per mechanism. Allowing duplicate functionality only serves to confuse the users of the API.
Strong typing allows for more error checking to be done at compile time; also, less error appear at runtime.
Because more often than not, the usual SQL calls
used by the programmer are simple SELECT’s,
INSERT’s,
DELETE’s
and UPDATE’s,
these queries should be simple to perform with JDBC. However, more complex SQL
statements should also be possible.
Finally we decided to precede the implementation using Java Networking.
And for dynamically updating the cache table we go for MS Access database.
Java ha two things: a programming language and a platform.
Java is a high-level programming language that is all of the following
Simple Architecture-neutral
Object-oriented Portable
Distributed High-performance
Interpreted Multithreaded
Robust Dynamic Secure
Java is also unusual in that each Java program is both compiled and interpreted. With a compile you translate a Java program into an intermediate language called Java byte codes the platform-independent code instruction is passed and run on the computer.
Compilation happens just once; interpretation occurs each time the program is executed. The figure illustrates how this works.
The TCP/IP stack is shorter than the OSI one:
TCP is a connection-oriented protocol; UDP (User Datagram Protocol) is a connectionless protocol.
The IP layer provides a connectionless and unreliable delivery system. It considers each datagram independently of the others. Any association between datagram must be supplied by the higher layers. The IP layer supplies a checksum that includes its own header. The header includes the source and destination addresses. The IP layer handles routing through an Internet. It is also responsible for breaking up large datagram into smaller ones for transmission and reassembling them at the other end.
UDP is also connectionless and unreliable. What it adds to IP is a checksum for the contents of the datagram and port numbers. These are used to give a client/server model – see later.
TCP supplies logic to give a reliable connection-oriented protocol above IP. It provides a virtual circuit that two processes can use to communicate.
In order to use a service, you must be able to find it. The Internet uses an address scheme for machines so that they can be located. The address is a 32 bit integer which gives the IP address.
Class A uses 8 bits for the network address with 24 bits left over for other addressing. Class B uses 16 bit network addressing. Class C uses 24 bit network addressing and class D uses all 32.
Internally, the UNIX network is divided into sub networks. Building 11 is currently on one sub network and uses 10-bit addressing, allowing 1024 different hosts.
8 bits are finally used for host addresses within our subnet. This places a limit of 256 machines that can be on the subnet.
The 32 bit address is usually written as 4 integers separated by dots.
A service exists on a host, and is identified by its port. This is a 16 bit number. To send a message to a server, you send it to the port for that service of the host that it is running on. This is not location transparency! Certain of these ports are “well known”.
A socket is a data structure maintained by the system
to handle network connections. A socket is created using the call socket. It returns an integer that is like a file descriptor.
In fact, under Windows, this handle can be used with Read File and Write File functions.
#include <sys/types.h>
#include <sys/socket.h>
int socket(int family, int type, int protocol);
Here “family” will be AF_INET for IP communications, protocol will be zero, and type will depend on whether TCP or UDP is used. Two
processes wishing to communicate over a network create a socket each. These are
similar to two ends of a pipe – but the actual pipe does not yet exist.
6.8 JFREE CHART:
JFreeChart is a free 100% Java chart library that makes it easy for developers to display professional quality charts in their applications. JFreeChart’s extensive feature set includes:
A consistent and well-documented API, supporting a wide range of chart types;
A flexible design that is easy to extend, and targets both server-side and client-side applications;
Support for many output types, including Swing components, image files (including PNG and JPEG), and vector graphics file formats (including PDF, EPS and SVG);
JFreeChart is “open source” or, more specifically, free software. It is distributed under the terms of the GNU Lesser General Public Licence (LGPL), which permits use in proprietary applications.
Charts showing values that relate to geographical areas. Some examples include: (a) population density in each state of the United States, (b) income per capita for each country in Europe, (c) life expectancy in each country of the world. The tasks in this project include: Sourcing freely redistributable vector outlines for the countries of the world, states/provinces in particular countries (USA in particular, but also other areas);
Creating an appropriate dataset interface (plus
default implementation), a rendered, and integrating this with the existing
XYPlot class in JFreeChart; Testing, documenting, testing some more,
documenting some more.
Implement a new (to JFreeChart) feature for interactive time series charts — to display a separate control that shows a small version of ALL the time series data, with a sliding “view” rectangle that allows you to select the subset of the time series data to display in the main chart.
There is currently a lot of interest in dashboard displays. Create a flexible dashboard mechanism that supports a subset of JFreeChart chart types (dials, pies, thermometers, bars, and lines/time series) that can be delivered easily via both Java Web Start and an applet.
The property editor mechanism in JFreeChart only
handles a small subset of the properties that can be set for charts. Extend (or
reimplement) this mechanism to provide greater end-user control over the
appearance of the charts.
CHAPTER 7
APPENDIX
7.1 SAMPLE SOURCE CODE
7.2
SAMPLE OUTPUT
CHAPTER 8
8.1 CONCLUSION
In this paper, we have studied the
threat imposed by falsely reporting users’ channel condition. Through case
studies for three different types of wireless network protocols, we show that
in a cooperative relaying network and a network using ETX, a false reporting
attack can significantly reduce the performance of other users. Our false
channel-feedback attack can arise in any channel-aware protocol where a user reports
its own channel condition. To counter such attacks, we propose a secure channel
condition estimation algorithm to prevent the overclaiming attack. Through analysis
and simulations, we show that with proper parameters, we can prevent the over claiming
attack.
CHAPTER 9
9.1 REFERENCES