java_arp.rar_ARP java_java arp

import java.net.Inet4Address; import java.net.InetAddress; import java.util.Arrays; import jpcap.*; import jpcap.packet.*; public class ARP { public static byte[] arp(InetAddress ip) throws java.io.IOException{ //find network interface NetworkInterface[] devices=JpcapCaptor.getDeviceList(); NetworkInterface device=null; loop: for(NetworkInterface d:devices){ for(NetworkInterfaceAddress addr:d.addresses){ if(!(addr.address instanceof Inet4Address)) continue; byte[] bip=ip.getAddress(); byte[] subnet=addr.subnet.getAddress(); byte[] bif=addr.address.getAddress(); for(int i=0;i<4;i++){ bip[i]=(byte)(bip[i]&subnet[i]); bif[i]=(byte)(bif[i]&subnet[i]); } if(Arrays.equals(bip,bif)){ device=d; break loop; } } } if(device==null) throw new IllegalArgumentException(ip+" is not a local address"); //open Jpcap JpcapCaptor captor=JpcapCaptor.openDevice(device,2000,false,3000); captor.setFilter("arp",true); JpcapSender sender=captor.getJpcapSenderInstance(); InetAddress srcip=null; for(NetworkInterfaceAddress addr:device.addresses) if(addr.address instanceof Inet4Address){ srcip=addr.address; break; } byte[] broadcast=new byte[]{(byte)255,(byte)255,(byte)255,(byte)255,(byte)255,(byte)255}; ARPPacket arp=new ARPPacket(); arp.hardtype=ARPPacket.HARDTYPE_ETHER; arp.prototype=ARPPacket.PROTOTYPE_IP; arp.operation=ARPPacket.ARP_REQUEST; arp.hlen=6; arp.plen=4; arp.sender_hardaddr=device.mac_address; arp.sender_protoaddr=srcip.getAddress(); arp.target_hardaddr=broadcast; arp.target_protoaddr=ip.getAddress(); EthernetPacket ether=new EthernetPacket(); ether.frametype=EthernetPacket.ETHERTYPE_ARP; ether.src_mac=device.mac_address; ether.dst_mac=broadcast; arp.datalink=ether; sender.sendPacket(arp); while(true){ ARPPacket p=(ARPPacket)captor.getPacket(); if(p==null){ throw new IllegalArgumentException(ip+" is not a local address"); } if(Arrays.equals(p.target_protoaddr,srcip.getAddress())){ return p.sender_hardaddr; } } } public static void main(String[] args) throws Exception{ if(args.length<1){ System.out.println("Usage: java ARP <ip address>"); }else{ byte[] mac=ARP.arp(InetAddress.getByName(args[0])); for (byte b : mac) System.out.print(Integer.toHexString(b&0xff) + ":"); System.out.println(); System.exit(0); } } }