accesspacket.java

j2me radius soket radius client

package org.radiusClient.com;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.DigestException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Random;

import javax.microedition.io.UDPDatagramConnection;


public class AccessPacket {
    public static final int MIN_PACKET_LENGTH       = 20;
    public static final int MAX_PACKET_LENGTH       = 4096;

    public static final short RADIUS_HEADER_LENGTH  = 20;
    public static final String EMPTYSTRING = "";

    String encoding = new String("ISO-8859-1");

    private int packet_size;
    public byte request[]=new byte[MAX_PACKET_LENGTH];
    byte buf[] = new byte[5001];
    private static int start=0;
    String local_host_IP;
    
    
    public AccessPacket(int id) 
    {
    	request[0]=(byte)1;
    	request[1]=(byte)id;
    	start = 20;
    }
    
    public synchronized byte[] composepacket(String username,String userpass,String secret,UDPDatagramConnection udpdc)
    {
    	byte RA[] = new byte[16];
    	byte[] requestbuffer;
    	Random rand = new Random();
    	
		for (int i = 0; i < 16; i++) {
			RA[i] = (byte) (rand.nextInt() % 256);
			request[4 + i] = RA[i];
		}

		int start = 20; // attribute start byte
		request[start] = (byte) 1; // attribute type for username
		request[start + 1] = (byte) (username.length() + 2);

		byte username_arr[] = null;

		try {
			username_arr = username.getBytes(encoding);
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

		int username_len = username.length();

		System.arraycopy(username_arr, 0, request, start + 2, username_len);

		start = start + 2 + username.length();

		// b_hash = MD5(S+RA)

		int sec_len = secret.length();

		byte[] S = new byte[sec_len];
		try {
			S = secret.getBytes(encoding);
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

		byte[] b = new byte[sec_len + 16];

		System.arraycopy(S, 0, b, 0, sec_len);

		System.arraycopy(RA, 0, b, sec_len, 16);

		byte[] b_hash = getKeyedDigest(b);

		// c = p XOR b_hash

		int userpass_len = userpass.length();
		byte[] p = new byte[16];

		byte[] p_temp = new byte[userpass_len];
		try {
			p_temp = userpass.getBytes(encoding);
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

		System.arraycopy(p_temp, 0, p, 0, userpass_len);

		for (int i = userpass_len; i < 16; i++) {
			p[i] = 0;

		}
		byte[] c1 = new byte[16];

		for (int i = 0; i < 16; i++) {
			c1[i] = (byte) ((int) p[i] ^ (int) b_hash[i]);

		}
		request[start] = (byte) 2; // attribute type for password
		request[start + 1] = (byte) 18;

		System.arraycopy(c1, 0, request, start + 2, 16);

		start = start + 18;
		
		request[start] = (byte) 4;
		request[start + 1] = (byte) 6;

		// local_host_IP = InetAddress.getLocalHost().toString();
		try {
			local_host_IP = udpdc.getLocalAddress();
		} catch (IOException e1) {
			// TODO Auto-generated catch block
			e1.printStackTrace();
		}
		int pos_slash = local_host_IP.indexOf("/");
		local_host_IP = local_host_IP.substring(pos_slash + 1, local_host_IP
				.length());

		byte[] byte_IP_Address = new byte[4];
		byte_IP_Address = String_to_ipaddr(local_host_IP);

		System.arraycopy(byte_IP_Address, 0, request, start + 2, 4);

		start = start + 6;

		packet_size = start; // packet length

		if (packet_size < 256) {
			request[2] = (byte) 0;
		}
		request[3] = (byte) start;
		requestbuffer = new byte[packet_size];
		for (int i = 0; i < packet_size; i++) {
			requestbuffer[i] = request[i];
		}
		return requestbuffer;
    }
    
	public byte[] getKeyedDigest(byte[] buffer) {
		int i;
		byte[] md5buf = null;
		try {
			MessageDigest md5 = MessageDigest.getInstance("MD5");
			md5.update(buffer, 0, buffer.length);

			try {
				i = md5.digest(buf, 0, 5000);
				md5buf = new byte[i];
				for (int j = 0; j < i; j++) {
					md5buf[j] = buf[j];
				}
			} catch (DigestException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		} catch (NoSuchAlgorithmException e) {
		}
		return md5buf;
	}
    
	public synchronized int String_to_int(String str) {
		int x = Integer.parseInt(str);
		return x;
	}

	public synchronized byte[] String_to_ipaddr(String IP_Address) { 																																			
		byte[] byte_IP_Address = new byte[4];
		String dot = new String(".");
		int pos_dot1 = 0, pos_dot2 = 0, pos_dot3 = 0; 
														

		pos_dot1 = IP_Address.indexOf(dot, 0);
		pos_dot2 = IP_Address.indexOf(dot, pos_dot1 + 1);
		pos_dot3 = IP_Address.indexOf(dot, pos_dot2 + 1);

		if (pos_dot1 != -1 && pos_dot2 != -1 && pos_dot3 != -1) {
			byte_IP_Address[0] = (byte) String_to_int(IP_Address.substring(0,
					pos_dot1));
			byte_IP_Address[1] = (byte) String_to_int(IP_Address.substring(
					pos_dot1 + 1, pos_dot2));
			byte_IP_Address[2] = (byte) String_to_int(IP_Address.substring(
					pos_dot2 + 1, pos_dot3));
			byte_IP_Address[3] = (byte) String_to_int(IP_Address.substring(
					pos_dot3 + 1, IP_Address.length()));
		}
		return byte_IP_Address;
	}

	public synchronized int byte_int0255(byte x_byte) {
		int x_int = x_byte & 0xFF;

		return x_int;
	}
	
    public void setAttribute(int type,String str)
    {
		request[start] = (byte) type; // attribute type for username
		request[start + 1] = (byte) (str.length() + 2);

		byte str_arr[] = null;

		try {
			str_arr = str.getBytes(encoding);
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

		int str_len = str.length();

		System.arraycopy(str_arr, 0, request, start + 2, str_len);

		start = start + 2 + str.length();
    }
    

}