content: package dk.aau.netsec.hostage.protocol.utils.cifs.smbutils;
  
  import java.nio.ByteBuffer;
  
  import dk.aau.netsec.hostage.commons.HelperUtils;
  
  
  /**
   * NetBIOS Name Service.
   * @author Wulf Pfeiffer
   */
  public class NBNS {
  	
  	private byte[] transactID;
  	private byte[] flags;
  	private byte[] questions;
  	private byte[] answerRRs;
  	private byte[] authorityRRs;
  	private byte[] additionalRRs;
  	private byte[] payload;
  	private byte[] additional;
  	private byte[] addr;
  	private byte[] name;
  	private int type;
  	private int service;
  	
  	public NBNS(byte[] addr) {
  		this.addr = addr;
  	}
  	
  	/**
  	 * Prepares the content for the next packet regarding of the set type.
  	 */
  	private void preparePacket() {
  		transactID = NMB.getAndIncTransactID();
  		switch (type) {
  		case NBNSType.REGISTRATION_UNIQUE:
  			prepareRegistrationPacket();
  			break;
  		case NBNSType.REGISTRATION_GROUP:
  			prepareRegistrationPacket();
  			break;
  		case NBNSType.NAME_QUERY:
  			prepareNameQueryPacket();
  			break;
  		case NBNSType.REGISTRATION_MSBROWSE:
  			prepareRegistrationMsBrowse();
  			break;
  		default:
  		}
  	}
  	
  	/**
  	 * Prepares the content for the next registration packet.
  	 */
  	private void prepareRegistrationPacket() {
  		flags = new byte[]{0x29, 0x10};
  		questions = new byte[]{0x00, 0x01};
  		answerRRs = new byte[]{0x00, 0x00};
  		authorityRRs = new byte[]{0x00, 0x00};
  		additionalRRs = new byte[]{0x00, 0x01};
  		payload = getPayload();
  		additional = getAdditionalRecords();
  	}
  	
  	/**
  	 * Prepares the content for the next name query packet.
  	 */
  	private void prepareNameQueryPacket() {
  		flags = new byte[] {0x01, 0x10};
  		questions = new byte[]{0x00, 0x01};
  		answerRRs = new byte[]{0x00, 0x00};
  		authorityRRs = new byte[]{0x00, 0x00};
  		additionalRRs = new byte[]{0x00, 0x00};
  		payload = getPayload();
  	}
  	
  	/**
  	 * Prepares the content for the next MSBROWSE registration packet.
  	 */
  	private void prepareRegistrationMsBrowse() {
  		flags = new byte[]{0x29, 0x10};
  		questions = new byte[]{0x00, 0x01};
  		answerRRs = new byte[]{0x00, 0x00};
  		authorityRRs = new byte[]{0x00, 0x00};
  		additionalRRs = new byte[]{0x00, 0x01};
  		payload = HelperUtils.concat(new byte[]{0x20, 0x41, 0x42, 0x41, 0x43}, name,
  				new byte[]{0x41, 0x43, 0x41, 0x42, 0x00, 0x00, 0x20, 0x00, 0x01});
  		additional = getAdditionalRecords();
  	}
  	
  	/**
  	 * Prepares the content for the next response packet.
  	 */
  	public void prepareResponsePacket(byte[] packet, byte[] myAddr) {
  		this.transactID = new byte[]{packet[0], packet[1]};
  		flags = new byte[]{(byte) 0x85, (byte) 0x80};
  		questions = new byte[]{0x00, 0x00};
  		answerRRs = new byte[]{0x00, 0x01};
  		authorityRRs = new byte[]{0x00, 0x00};
  		additionalRRs = new byte[]{0x00, 0x00};
  		byte[] nameBytes = new byte[32]; 
  		System.arraycopy(packet, 13, nameBytes, 0, 32);
  		String name = NMBStringCoder.decodeNBNSName(nameBytes);
  		byte[] query = new byte[50];
  		System.arraycopy(packet, 12, query, 0, 38);
  		// time to live
  		query[38] = 0x00;
  		query[39] = 0x00;
  		query[40] = 0x02;
  		query[41] = 0x58;
  		// data length
  		query[42] = 0x00;
  		query[43] = 0x06;
  		// name flags
  		query[44] = (byte) 0x80;
  		query[45] = 0x00;
  		// addr
  		query[46] = myAddr[0];
  		query[47] = myAddr[1];
  		query[48] = myAddr[2];
  		query[49] = myAddr[3];
  		payload = query;
  	}
  	
  	/**
  	 * Builds the payload for the packet.
  	 * @return payload.
  	 */
  	private byte[] getPayload() {
  		byte[] payload = NMBStringCoder.wrapNBNSName(this.name, service);
  		byte[] type = {0x00, 0x20};
  		byte[] nbnsclass = {0x00, 0x01};
  		return HelperUtils.concat(payload, type, nbnsclass);
  	}
  
  	/**
  	 * Builds the additional records field.
  	 * @return additional records.
  	 */
  	private byte[] getAdditionalRecords() {
  		byte[] name = {(byte) 0xc0, 0x0c};
  		byte[] type = {0x00, 0x20};
  		byte[] nbnsclass = {0x00, 0x01};
  		byte[] timeToLive = {0x00, 0x00, 0x00, 0x00};
  		byte[] nameFlags = ((this.type == NBNSType.REGISTRATION_UNIQUE) ? new byte[]{0x00, 0x00} : new byte[]{(byte) 0x80, 0x00});
  		byte[] buffer = ByteBuffer.allocate(4).putInt(nameFlags.length + addr.length).array();
  		byte[] length = {buffer[2], buffer[3]};
  		return HelperUtils.concat(name, type, nbnsclass, timeToLive, length, nameFlags, addr);
  	}
  	
  	/**
  	 * Returns the next packet.
  	 * Use only after the name, type and service were set.
  	 * @return next packet.
  	 */
  	public byte[] getNextPacket() {
  		preparePacket();
  		return getBytes();
  	}
  	
  	/**
  	 * Returns the next response packet.
  	 * @param packet request packet.
  	 * @param myAddr your current ip in bytes.
  	 * @return next response packet.
  	 */
  	public byte[] getNextResponse(byte[] packet, byte[] myAddr) {
  		prepareResponsePacket(packet, myAddr);
  		return getBytes();
  	}
  
  	/**
  	 * Returns the content of the packet in bytes.
  	 * @return packet content.
  	 */
  	private byte[] getBytes() {
  		return HelperUtils.concat(transactID, flags, questions, answerRRs, authorityRRs, additionalRRs, payload, additional);
  	}
  
  	/**
  	 * Set the name for the payload.
  	 * @param name
  	 */
  	public void setName(String name) {
  		this.name = name.getBytes();
  		this.name = NMBStringCoder.encodeNBNSName(this.name);
  	}
  
  	/**
  	 * Set the NBNSType.
  	 * @param type NBNSType.
  	 */
  	public void setType(int type) {
  		this.type = type;
  	}
  
  	/**
  	 * Set the NBNSService.
  	 * @param service NBNSService.
  	 */
  	public void setService(int service) {
  		this.service = service;
  	}
  
  }
  