JAVA(Networking)

(Jpcap: Capturing and displaying packet traffic with

JpcapCapturePacket and receivePacket)JPCAP:

Jpcap is an open source network packet capture library based

on the libpcap and winpcap libraries that you can use with java to

capture and display network traffic on Linux, Windows and Macintosh

computers. Jpcap capture Ethernet, TCP, UDP, IPv4, IPv6, ARP/RARP,

and TCMPv4 packets and analyzes each packet’s header and data

payload.

USING JPCAP:

There are several dependencies and requirements you will need

to meet before being able to use Jpcap in your Java project. To write

Java application using Jpcap you will need to:

1. Download and install winpcap:

Link=http://www.winpcap.org/install/default.html

2. Download and install Jpcap: Link=

http://netresearch.ics.uci.edu.kfhjiii/jpcap/doc/index.html

The default install routine for Jpcap may not put things in the

right place for you particular development environment.

Therefore, after installing Jpcap to extract the files find “Jpcap.dll”

and “Jpcap.jar” on your system.

3. Copy “Jpcap.dll” into “[JRE directory]\bin or [JRE directory]\lib\ext\

x86”

4. Copy “Jpcap.jar” into “[JRE directory]\bin or [JRE directory]\lib\

ext”

5. Copy “Jpcap.jar” into “[JRE directory]\bin or [JRE directory]\jre\lib\

ext”

(Note: if you have the 64bit JDK an JRE and download the 32bit

version, you will need copy the files to that Platform’s and JDK

folder as well)

6. If are using the 64bit JDK and JRE, download and use the 32 bit

JDK and JRE. If you using Netbean you can add it as an additional

platform and select between 32 and 64 bit version when

necessary.

7. If you using Netbean, right-click on project “Property” and select

“Libraries”. Then select the 32-bit JDK from Java Platform

dropdown list.

8. Click the “JAR/Folder” button under project “Properties” and

“Libraries” and add the “jpacp.jar” file in to your project.

9. When running Applications that use Jpcap you need ROOT

privileges in Linux and Administrative privileges in Windows. You

will get run-time error if you attempt to you Jpcap without the

appropriate privileges. If you using Netbean in Window, rt-click

and choose “Run as Administrator”. In linux, you can hit ALT+F2

and type “gksudo Netbeans”.

10. All done! Now you can start coding project using Jpcap

Here are some Jpcap class we will be using:

1. Packet= a Jpcap class that is instantiabed for each packet

capture and used to access that packet’s field information and

data.

2. JpcapCaptor= a Jpcap class with many methods for capturing

and filtering packets.

Here are some method Jpcap functions we will be using:

1. getDeiviceList()= return an array of NetworkInterface objects

for each network interface on the specified.

2. openDevice()= opens the specified network interface. It’s

argument are: 1= network interface to open, 2= max # bytes

captured at once, 3= promiscuous node (true or false), 4= time

out for capture.

3. setFilter()= set port filter options. Take 2 argument: 1= String

of to filter, 2= optimize(true or false).

4. loopPacket()=captures packets for specified # of itearions.

Take 2 arguments: 1= # capture (-1=infinite), 2= new instance

of a class that implements the PacketReceiver interface.

IGNORES timeout and does NOT support “non-blocking” mode.

5. processPacket()= captures packets for specified # of iterations.

Take 2 arguments: 1= #capture(-1=infinite), 2= new instance of

a class that implement the PacketReceiver interface. ACCEPT

timeout and SUPPORT “non-blocking” mode(return immediately

when there’s nothing to capture).

6. getPacket()= capture a single packet.

7. breakLoop()= force loopPacket and processPacket to stop

looping and return.

8. setPacketReadTimeout()= set the timeout values.

9. getPacketReadTiomeout()= retrieves the timeout values.