Codec.java

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/*
 * $Id: Codec.java 2 2006-11-14 22:37:20Z vingarzan $
 *
 * Copyright (C) 2004-2006 FhG Fokus
 *
 * This file is part of Open IMS Core - an open source IMS CSCFs & HSS
 * implementation
 *
 * Open IMS Core is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * For a license to use the Open IMS Core software under conditions
 * other than those described here, or to purchase support for this
 * software, please contact Fraunhofer FOKUS by e-mail at the following
 * addresses:
 *     info@open-ims.org
 *
 * Open IMS Core is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

package de.fhg.fokus.diameter.DiameterPeer.data;

import java.util.Arrays;
import java.util.Vector;



public class Codec {

    public static AVP decodeAVP(byte[] from,int start) throws AVPDecodeException
    {
        AVP to = new AVP();
        int i,j,len;
        
        if (from.length-start<8) throw new AVPDecodeException("Data is shorter than AVP Header");
        
        to.code =   ((int)from[start+0]&0xFF)<<24 |
                    ((int)from[start+1]&0xFF)<<16 |
                    ((int)from[start+2]&0xFF)<< 8 |
                    ((int)from[start+3]&0xFF);
        
        to.flag_vendor_specific =   (from[start+4] & 0x80)!=0;
        to.flag_mandatory =         (from[start+4] & 0x40)!=0;
        to.flag_protected =         (from[start+4] & 0x20)!=0;
        len =   ((int)from[start+5]&0xFF)<<16 |
                ((int)from[start+6]&0xFF)<< 8 |
                ((int)from[start+7]&0xFF);

        if (to.flag_vendor_specific){
            to.vendor_id =  ((int)from[start+ 8]&0xFF)<<24 |
                            ((int)from[start+ 9]&0xFF)<<16 |
                            ((int)from[start+10]&0xFF)<< 8 |
                            ((int)from[start+11]&0xFF);
            j = 12;
        } else {
            to.vendor_id = 0;
            j = 8;
        }

        if (len>from.length-start) len = from.length-start;
        to.data = new byte[len-j];
        System.arraycopy(from,start+j,to.data,0,len-j);
        
        if (len!=0)
        for(i=0;i<4&&i<len-j;i++)
            to.int_data = (to.int_data<<8)| ((byte) to.data[i]&0xFF);
        
        to.encoded_length = len;
        if (to.encoded_length%4!=0) 
            to.encoded_length = (to.encoded_length/4+1)*4; 
        
        return to;
    }

    public static byte[] encodeAVP(AVP from)
    {
        byte[] to = null;
        int total_len,send_len;
        int j;

        /* if it is ungrouped, we group it first */
        if (from.is_ungrouped)
            from.group();
        
        total_len=4+4+from.data.length;
        
        if (from.flag_vendor_specific) total_len+=4;
        send_len = total_len;
        if (total_len%4!=0) 
            total_len = (total_len/4+1)*4; 
        to = new byte[total_len];
        Arrays.fill(to,(byte)0);
        
        to[0] = (byte) ((from.code >> 24) & 0xFF);
        to[1] = (byte) ((from.code >> 16) & 0xFF);
        to[2] = (byte) ((from.code >>  8) & 0xFF);
        to[3] = (byte) ( from.code        & 0xFF);
        
        if (from.flag_vendor_specific) to[4] |= 0x80;
        if (from.flag_mandatory) to[4] |= 0x40;
        if (from.flag_protected) to[4] |= 0x20;
        to[5] = (byte) ((send_len >> 16) & 0xFF);
        to[6] = (byte) ((send_len >>  8) & 0xFF);
        to[7] = (byte) ( send_len        & 0xFF);
        
        if (from.flag_vendor_specific){
            to[ 8] = (byte) ((from.vendor_id >> 24) & 0xFF);
            to[ 9] = (byte) ((from.vendor_id >> 16) & 0xFF);
            to[10] = (byte) ((from.vendor_id >>  8) & 0xFF);
            to[11] = (byte) ( from.vendor_id        & 0xFF);
            j = 12;
        }
        else j = 8;
        
        if (from.data.length!=0)
            System.arraycopy(from.data,0,to,j,from.data.length);
    
        return to;
    }
    
    public static int getEncodedAVPSize(AVP avp)
    {
        AVP avp2;
        int datalen=0;
        int i;
        if (avp.is_ungrouped&&avp.childs!=null){
            for(i=0;i<avp.childs.size();i++){
                avp2 = (AVP) avp.childs.get(i);
                datalen += getEncodedAVPSize(avp2);
            }   
        }else{
            datalen += avp.data.length;
            if (datalen%4!=0) datalen = (datalen/4+1)*4;
        }
        if (avp.flag_vendor_specific) return 12+datalen;
        else return 8+datalen;
    }
    
    public static DiameterMessage decodeDiameterMessage(byte[] from,int start) throws DiameterMessageDecodeException
    {
        DiameterMessage to = new DiameterMessage();
        int i,len;
        AVP avp;
        
        if (from.length-start<20) throw new DiameterMessageDecodeException("Data is shorter than Diameter Message Header");
        
        to.version = ((int)from[start+0]&0xFF);
        if (to.version!=1) throw new DiameterMessageDecodeException("Unknown Diameter Message Version "+to.version);
        
        len =   ((int)from[start+ 1]&0xFF)<<16 |
                ((int)from[start+ 2]&0xFF)<< 8 |
                ((int)from[start+ 3]&0xFF);
        
        if (len>from.length-start) len=from.length-start;
        
        to.flagRequest =            (from[start+4] & 0x80)!=0;
        to.flagProxiable =      (from[start+4] & 0x40)!=0;
        to.flagError =          (from[start+4] & 0x20)!=0;
        to.flagRetransmission =     (from[start+4] & 0x10)!=0;

        to.commandCode =    ((int)from[start+ 5]&0xFF)<<16 |
                            ((int)from[start+ 6]&0xFF)<< 8 |
                            ((int)from[start+ 7]&0xFF);
        
        to.applicationID =  ((int)from[start+ 8]&0xFF)<<24 |
                            ((int)from[start+ 9]&0xFF)<<16 |
                            ((int)from[start+10]&0xFF)<< 8 |
                            ((int)from[start+11]&0xFF);

        to.hopByHopID = ((int)from[start+12]&0xFF)<<24 |
                            ((int)from[start+13]&0xFF)<<16 |
                            ((int)from[start+14]&0xFF)<< 8 |
                            ((int)from[start+15]&0xFF);

        to.endToEndID = ((int)from[start+16]&0xFF)<<24 |
                            ((int)from[start+17]&0xFF)<<16 |
                            ((int)from[start+18]&0xFF)<< 8 |
                            ((int)from[start+19]&0xFF);

        i = start+20;
        while (i<start+len){
            try {
                avp = Codec.decodeAVP(from,i);
            } catch (AVPDecodeException e) {
                e.printStackTrace();
                throw new DiameterMessageDecodeException(e.getMessage());
            }
            to.avps.add(avp);
            i+=avp.encoded_length;
        }       
        return to;
    }
    
    public static byte[] encodeDiameterMessage(DiameterMessage from)
    {
        byte[] to = null;
        int total_len;
        int i,len=0;
        Vector<byte[]> temp;
        byte[] t;
        
        temp = new Vector<byte[]>();
        for(i=0;i<from.avps.size();i++){
            t = Codec.encodeAVP((AVP)from.avps.get(i));
            temp.add(t);
            len += t.length;
        }
        total_len=20+len;
        
        to = new byte[total_len];
        Arrays.fill(to,(byte)0);

        to[0] = (byte) ( from.version     & 0xFF);
        to[1] = (byte) ((total_len >> 16) & 0xFF);
        to[2] = (byte) ((total_len >>  8) & 0xFF);
        to[3] = (byte) ( total_len        & 0xFF);
        
        if (from.flagRequest)           to[4] |= 0x80;
        if (from.flagProxiable)         to[4] |= 0x40;
        if (from.flagError)             to[4] |= 0x20;
        if (from.flagRetransmission)    to[4] |= 0x10;
        to[5] = (byte) ((from.commandCode >> 16) & 0xFF);
        to[6] = (byte) ((from.commandCode >>  8) & 0xFF);
        to[7] = (byte) ( from.commandCode        & 0xFF);
        
        to[ 8] = (byte) ((from.applicationID >> 24) & 0xFF);
        to[ 9] = (byte) ((from.applicationID >> 16) & 0xFF);
        to[10] = (byte) ((from.applicationID >>  8) & 0xFF);
        to[11] = (byte) ( from.applicationID        & 0xFF);        

        to[12] = (byte) ((from.hopByHopID >> 24) & 0xFF);
        to[13] = (byte) ((from.hopByHopID >> 16) & 0xFF);
        to[14] = (byte) ((from.hopByHopID >>  8) & 0xFF);
        to[15] = (byte) ( from.hopByHopID        & 0xFF);       

        to[16] = (byte) ((from.endToEndID >> 24) & 0xFF);
        to[17] = (byte) ((from.endToEndID >> 16) & 0xFF);
        to[18] = (byte) ((from.endToEndID >>  8) & 0xFF);
        to[19] = (byte) ( from.endToEndID        & 0xFF);       

        len = 20;
        for(i=0;i<temp.size();i++){
            t = temp.get(i);
            System.arraycopy(t,0,to,len,t.length);
            len += t.length;
        }       
    
        return to;
    }

}

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