Jpcap
By Jon Hoffman, July 31, 2006
Have you ever tried to write a systems administration or network security application in Java? If so, you know that Java lacks the necessarily low-level network functionality needed for these types of applications. You cannot handcraft a TCP/IP packet, set the flags, or even ping a computer with the standard Java network classes. That is where jpcap comes in.
Listing 3 myIpaddress method
public byte[] myIPAddress(int networkInterfaceID)
{
/* Verify that we obtained a valid networkInterfaceID */
if (networkInterfaceID < 0 || devices.length <= networkInterfaceID)
return null;
/* Set device to the network interface specified by the
networkInterfaceID */
NetworkInterface device = devices[networkInterfaceID];
/* Get the array of IP addresses assigned to the network interface
specified by the networkInterfaceID */
NetworkInterfaceAddress[] addresses = devices[networkInterfaceID].addresses;
/* Network interfaces can have multiple IP addresses assigned to them
but in this example we are only grabbing the first address. */
InetAddress address = addresses[0].address;
/* Convert the IP address to an array of bytes and return it to
the method that called this function */
byte[] returnByte = address.getAddress();
return returnByte;
}
