/protocols/ss7/mtp/mtp-impl/src/main/java/org/mobicents/protocols/ss7/mtp/Mtp3.java

/*

 * JBoss, Home of Professional Open Source

 * Copyright 2011, Red Hat, Inc. and individual contributors

 * by the @authors tag. See the copyright.txt in the distribution for a

 * full listing of individual contributors.

 *

 * This is free software; you can redistribute it and/or modify it

 * under the terms of the GNU Lesser General Public License as

 * published by the Free Software Foundation; either version 2.1 of

 * the License, or (at your option) any later version.

 *

 * This software 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this software; if not, write to the Free

 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA

 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.

 */



package org.mobicents.protocols.ss7.mtp;



import java.io.IOException;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;



import javolution.util.FastList;



import org.apache.log4j.Level;

import org.apache.log4j.Logger;

import org.mobicents.protocols.stream.api.SelectorKey;

import org.mobicents.protocols.stream.api.SelectorProvider;

import org.mobicents.protocols.stream.api.StreamSelector;



/**

 * 

 * @author kulikov

 * @author baranowb

 */

public class Mtp3 implements Runnable {



    public final static int TIMEOUT_T1_SLTM = 12;

    public final static int TIMEOUT_T2_SLTM = 90;

    private final static int LINK_MANAGEMENT = 0;

    private final static int LINK_TESTING = 1;

    public final static int _SI_SERVICE_SCCP = 3;

    public final static int _SI_SERVICE_ISUP = 5;

    

    private Mtp3Listener mtp3Listener;

    /**

     * Flag indicating if we should notify upper layer

     */

    private boolean l4IsUp = false;

    

    //FIXME: MOVE THIS TO LINKSET?

    protected volatile boolean started = false;

    /** defautl value of SSI */

    public static final int DEFAULT_NI = 2;//NATIONAL, as default.

    

    private int dpc;

    private int opc;

    private int ni=DEFAULT_NI << 2; // << cause its faster for checks.

    /**

     * Local byte[], in which we forge messages.

     */

    private byte[] localFrame = new byte[279]; 

    private byte[][] localBuffers;

    /** List of signaling channels wrapped with MTP2*/

    private List<Mtp2> links = new ArrayList();

    

    /** Active links */

    private Linkset linkset = new Linkset();    

    // ss7 has subservice as 1, q704 shows the same iirc

    //private int subservice = -1;

    //private int service;

  

    

    // //////////////////////////

    // SLTM pattern for inits //

    // //////////////////////////

    private final static byte[] SLTM_PATTERN = new byte[]{0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x0F};

    

    protected String name;

    private StreamSelector selector;

    

    private MTPScheduler executor = new MTPScheduler();



    private static final Logger logger = Logger.getLogger(Mtp3.class);

    

    //public Mtp3Impl(String name, Mtp1 layer1) {

    public Mtp3(String name) {

        this.name = name;

        try {

            selector = SelectorProvider.getSelector("org.mobicents.ss7.hardware.dahdi.Selector");

        } catch (Exception e) {

            e.printStackTrace();

        }

        this.localBuffers = new byte[300][];

        for(int i=0;i<300;i++)

        {

        	this.localBuffers[i] = new byte[i];

        }

    }



    /**

     * Assigns originated point code

     * 

     * @param opc the originated point code

     */

    public void setOpc(int opc) {

        this.opc = opc;

    }



    /**

     * Assigns destination point code.

     * 

     * @param dpc destination point code in decimal format.

     */

    public void setDpc(int dpc) {

        this.dpc = dpc;

    }



    /**

     * @return the dpc

     */

    public int getDpc() {

        return dpc;

    }



    /**

     * @return the opc

     */

    public int getOpc() {

        return opc;

    }



    

    /**

     * Sets network indicator to be used as part of SIO( actually SSI). It Accepts 2 bit integer.

     * @param ni

     */

    public void setNetworkIndicator(int ni){

		this.ni = (0x03 & ni) << 2; 

	}

    

    public int getNetworkIndicator() {

		return this.ni >> 2;

	}



	/** (non-Javadoc)

     * @see org.mobicents.protocols.ss7.mtp.Mtp3#addMtp3Listener(org.mobicents.protocols.ss7.mtp.Mtp3Listener)

     */

    public void addMtp3Listener(Mtp3Listener lst) {

        if (this.mtp3Listener != null) {

            throw new IllegalStateException("Listener already present.");

        }

        this.mtp3Listener = lst;

        

    }



    /* (non-Javadoc)

     * @see org.mobicents.protocols.ss7.mtp.Mtp3#removeMtp3Listener(org.mobicents.protocols.ss7.mtp.Mtp3Listener)

     */

    public void removeMtp3Listener(Mtp3Listener lst) {

        if (lst != this.mtp3Listener) {

            throw new IllegalArgumentException("Wrong listener passed. Its not registered in this object!");

        }

        this.mtp3Listener = null;

        

    }



    /* (non-Javadoc)

     * @see org.mobicents.protocols.ss7.mtp.Mtp3#setLinks(java.util.List)

     */

    public void setLinks(List<Mtp2> channels) {

        for (Mtp2 link : channels) {

            if (link != null) {

                link.mtp3 = this;

                this.links.add(link);

            }

        }

        

    }

    

    public void addLink(Mtp2 mtp2){

    	mtp2.mtp3 = this;

    	this.links.add(mtp2);

    }

    

    public void clearLinks(){

    	this.links.clear();

    }



    /**

     * Starts linkset.

     * 

     * @throws java.io.IOException

     */

    public void start() throws IOException {

        //starting links

        for (Mtp2 link : links) {

            link.start();

        }        

    }



    public void stop() throws IOException {

        started = false;

        for (Mtp2 link : links) {

            //selector.unregister(link);

            link.stop();

        }        

    }



    public void run() {

        try {

            FastList<SelectorKey> selected = selector.selectNow(StreamSelector.OP_READ, 20);

            for (FastList.Node<SelectorKey> n = selected.head(), end = selected.tail(); (n = n.getNext()) != end;) {

                ((Mtp2)((Mtp1) n.getValue().getStream()).getLink()).doRead();

            }

                 

            selected = selector.selectNow(StreamSelector.OP_WRITE, 20);

            for (FastList.Node<SelectorKey> n = selected.head(), end = selected.tail(); (n = n.getNext()) != end;) {

                ((Mtp2)((Mtp1)  n.getValue().getStream()).getLink()).doWrite();

            }

                

            this.executor.tick();

                

            for (Mtp2 link : links) {

                link.scheduler.tick();

            }

        } catch (Exception e) {

                e.printStackTrace();

        }

    }



    /**

     * This method is called when new MSU is detected.

     * 

     * @param sio

     *            service information octet.

     * @param msg

     *            service information field;

     */

    

    public void onMessage(Mtp2Buffer rxFrame, Mtp2 mtp2)

    {   

    	//                   | ----------------------- TO L4 --------------------------- |

    	//                          | --------------------- SIF ------------------------ |

    	//FSN   BSN   LEN    SIO    DPC/OPC,SLS    HEADING     LEN

    	//b1    b0    0e     01     01 80 00 00    21          70    01 02 03 04 05 06 0f  CRC CRC

    	int sio = rxFrame.frame[3] & 0xFF;

    	int subserviceIndicator = (sio >> 4) & 0x0F;

        int serviceIndicator = sio & 0x0F;

        int ni = (subserviceIndicator  & 0x0C) ; //local NI(network Indicator) form msg., 0x0C, since we store it as shifted value.

        // int dpc = (sif[0] & 0xff | ((sif[1] & 0x3f) << 8));

        // int opc = ((sif[1] & 0xC0) >> 6) | ((sif[2] & 0xff) << 2) | ((sif[3]

        // & 0x0f) << 10);

        // int sls = (sif[3] & 0xf0) >>> 4;

        int dpc = dpc(rxFrame.frame, 4); //1 - cause sif contains sio, even though its also passed as arg.

        int opc = opc(rxFrame.frame, 4);

        int sls = sls(rxFrame.frame, 4);

        

        //check SSI, Q.704 Figure 25, seems like if its bad, we discard.

        if(this.ni!=ni)

        {

        	if (logger.isEnabledFor(Level.ERROR)) {

                logger.error(

                        String.format("(%s) Received MSSU with bad SSI, discarding! [si=" + serviceIndicator + ",ssi=" + subserviceIndicator + ", dpc=" + dpc + ", opc=" + opc + ", sls=" + sls + "] data: ", mtp2.getName()) + Arrays.toString(rxFrame.frame));

            }

        	return;

        }

        



        switch (serviceIndicator) {

            case LINK_MANAGEMENT:

                int h0 = rxFrame.frame[8] & 0x0f;

                int h1 = (rxFrame.frame[8] & 0xf0) >>> 4;

                

                if (logger.isDebugEnabled()) {

                    logger.debug(String.format("(%s) Signalling network management", mtp2.getName()));

                }

                

                if (h0 == 0) {

                    if (logger.isDebugEnabled()) {

                        logger.debug(String.format("(%s) Changeover management", mtp2.getName()));

                    }

                } else if (h0 == 7 && h1 == 1) {

                    if (logger.isDebugEnabled()) {

                        logger.debug(String.format("(%s) TRA received", mtp2.getName()));

                    }

                }

                //FIX ME

                break;

            case LINK_TESTING:

                h0 = rxFrame.frame[8] & 0x0f;

                h1 = (rxFrame.frame[8] & 0xf0) >>> 4;



                int len = (rxFrame.frame[9] & 0xf0) >>> 4;



                if (h0 == 1 && h1 == 1) {

                	if (logger.isDebugEnabled()) {

                        logger.debug(String.format("(%s) Received SLTM", mtp2.getName()));

                    }

                    // receive SLTM from remote end

                    // create response



                    //change order of opc/dpc in SLTA !

                    writeRoutingLabel(this.localFrame, sio, this.ni << 2, sls, opc, dpc);

                    //slta[0] = (byte) sio;

                    this.localFrame[5] = 0x021;

                    // +1 cause we copy LEN byte also.

                    System.arraycopy(rxFrame.frame, 9, this.localFrame, 6, len + 1);



                    if (logger.isDebugEnabled()) {

                        logger.debug(String.format("(%s) Responding with SLTA", mtp2.getName()));

                    }

                    mtp2.send( this.localFrame, len+9);

                } else if (h0 == 1 && h1 == 2) {

                    // receive SLTA from remote end

                	if (logger.isDebugEnabled()) {

                        logger.debug(String.format("(%s) Received SLTA", mtp2.getName()));

                    }



                    //checking pattern

                    if (checkPattern(rxFrame,len, SLTM_PATTERN)) {

                        //test message is acknowledged

                        mtp2.sltmTest.ack();



                        //notify top layer that link is up

                        if (!l4IsUp) {

                            l4IsUp = true;

                            linkUp(mtp2);

                        }

                    } else {

                    	if(logger.isEnabledFor(Level.WARN))

                    	{

                    		logger.warn("SLTA pattern does not match: \n"+Arrays.toString(rxFrame.frame)+"\n"+Arrays.toString(SLTM_PATTERN));

                    	}

                    }

                } else {

                	if(logger.isEnabledFor(Level.WARN))

                	{

                		logger.warn(String.format("(%s) Unexpected message type", mtp2.getName()));

                	}

                }

                break;

            case _SI_SERVICE_SCCP:

            	if (logger.isDebugEnabled()) {

                    logger.debug("Received SCCP MSU");

                }



                if (mtp3Listener != null) {

                    

                    //                   | ----------------------- TO L4 --------------------------- |

                	//                          | --------------------- SIF ------------------------ |

                	//FSN   BSN   LEN    SIO    DPC/OPC,SLS    HEADING     LEN

                	//b1    b0    0e     01     01 80 00 00    21          70    01 02 03 04 05 06 0f  CRC CRC

                	byte[] messageBuffer = fetchBuffer(rxFrame.len-5); //-5 = FSN(1) + BSN(1) + LEN(1) +2xCRC(1)

                    System.arraycopy(rxFrame.frame, 3, messageBuffer, 0, rxFrame.len-5);

                    //messageBuffer[0] = (byte) sio;

                    try {

                        mtp3Listener.receive(messageBuffer);

                    } catch (Exception e) {

                        e.printStackTrace();

                    }

                }

                break;

            case _SI_SERVICE_ISUP:

            	if (logger.isDebugEnabled()) {

                    logger.debug("Received ISUP MSU");

                    

                }

                if (mtp3Listener != null) {

                	byte[] messageBuffer = fetchBuffer(rxFrame.len-5);

                	 System.arraycopy(rxFrame.frame, 3, messageBuffer, 0, rxFrame.len-5);

                     //messageBuffer[0] = (byte) sio;

                    try {

                        mtp3Listener.receive(messageBuffer);

                    } catch (Exception e) {

                        e.printStackTrace();

                    }

                }

                break;

            default:

                if (logger.isEnabledFor(Level.WARN) ) {

                    logger.warn("Received MSU for UNKNOWN SERVICE!!!!!!!!!!!: " + Utils.dump(rxFrame.frame, rxFrame.len, false));

                }

                break;

        }

    }

 



	/**

     * Selects link for transmission using link selection indicator.

     * 

     * @param sls signaling link selection indicator.

     * @return selected link.

     */

    private Mtp2 selectLink(byte sls) {

        

        return linkset.select(sls);

    }

    

    public boolean send(byte[] msg, int len) {

        //method expects proper message, lets pray its ok :/ - this is a way to be aligned with dialogic cards.

        //selecting link using sls

        //get sls;

        byte sls = (byte) sls(msg, 1);

        Mtp2 link = this.selectLink(sls);

        

        if (link == null) {

            return false;

        }

        

        return link.send(msg, len);

    }



    public void linkInService(Mtp2 link) {

        //restart traffic 

        if (logger.isDebugEnabled()) {

            logger.debug(String.format("(%s) Sending TRA(Traffic Restart Allowed) message", link.getName()));

        }

        

        if(link.mtp2Listener != null){

            link.mtp2Listener.linkInService();

        }

        

        restartTraffic(link);



        //create and assign Tester;

        if (link.sltmTest == null) {

            SLTMTest tester = new SLTMTest(link);

            link.sltmTest =(tester);



            //start tester

            if (logger.isDebugEnabled()) {

                logger.debug(String.format("(%s) Starting link test procedure(SLTM/SLTA)", link.getName()));

            }

            tester.start();

        } else {

            link.sltmTest.start();

        }

    }



    /**

     * Notify that link is up.

     * @param link

     */

    private void linkUp(Mtp2 link) {

        

        if(link.mtp2Listener != null){

            link.mtp2Listener.linkUp();

        }

        

        linkset.add(link);

        if (linkset.isActive() && this.mtp3Listener != null) {

            try {

                mtp3Listener.linkUp();

            } catch (Exception e) {

                e.printStackTrace();

            }

        }

        if (logger.isInfoEnabled()) {

            logger.info(String.format("(%s) Link now IN_SERVICE", link.getName()));

        }

    }

    

    public void linkFailed(Mtp2 link) {

        

        //Call Listener

        if(link.mtp2Listener != null){

            link.mtp2Listener.linkFailed();

        }

        

    	//FIXME: add debug or trace?

        //remove this link from list of active links

        linkset.remove(link);



        //restart initial alignment after T17 expires

        link.fail();



        //notify mtp user part

        if (!linkset.isActive()) {

            l4IsUp = false;

            if (mtp3Listener != null) {

                try {

                    mtp3Listener.linkDown();

                } catch (Exception e) {

                    e.printStackTrace();

                }

            }

        }

    }



    /* (non-Javadoc)

     * @see org.mobicents.protocols.ss7.mtp.Mtp2Listener#registerLink(org.mobicents.protocols.ss7.mtp.Mtp2)

     */

    public void registerLink(Mtp2 mtp2) {

        try {

            mtp2.getLayer1().register(selector);

        } catch (IOException ex) {

            ex.printStackTrace();

        }

    }



    /* (non-Javadoc)

     * @see org.mobicents.protocols.ss7.mtp.Mtp2Listener#unregisterLink(org.mobicents.protocols.ss7.mtp.Mtp2)

     */

    public void unregisterLink(Mtp2 mtp2) {

    }



    private void restartTraffic(Mtp2 link) {



        writeRoutingLabel(this.localFrame, 0, this.ni, 0, dpc, opc);



        // H0 and H1, see Q.704 section 15.11.2+

        this.localFrame[5] = 0x17;

        link.send(this.localFrame, 6);

    }   

    

    private final static int PATTERN_OFFSET = 10;

    private final static int PATTERN_LEN_OFFSET = PATTERN_OFFSET+2; //+2 becuase frame.len contains 2B for CRC



    private boolean checkPattern(Mtp2Buffer frame,int sltmLen, byte[] pattern) {

        if (frame.len - PATTERN_LEN_OFFSET != pattern.length) {

            return false;

        }

        for (int i = 0; i < pattern.length; i++) {

            if (frame.frame[ i + PATTERN_OFFSET ] != pattern[i]) {     	

                return false;

            }

        }

        return true;

    }

    

    /**

	 * @param i

	 * @return

	 */

	private byte[] fetchBuffer(int size) {

		return this.localBuffers[size];

	}

    protected class SLTMTest extends MTPTask {



        private Mtp2 link;

        private int tryCount;        //SLTM message buffer;

        private byte[] sltm = new byte[7 + SLTM_PATTERN.length]; //this has to be separate, cause its async to Mtp3.send

        

        private SLTMTest(Mtp2 link) {

            this.link = link;

        }



        /**

         * 

         */

        public void start() {

            //reset count of tries

            tryCount = 0;



            //sending test message to the remote terminal

            run();

        }

        

        public void stop() {

            //disable handler

            cancel();

        }



        /**

         * This methods should be called to acknowledge that current tests is passed.

         * 

         */

        public void ack() {

            //disable current awaiting handler

            cancel();

            //reset number of tryies;

            tryCount = 0;

            //shcedule next ping

            executor.schedule(this, Mtp3.TIMEOUT_T2_SLTM * 1000);

            if (logger.isDebugEnabled()) {

                logger.debug(String.format("(%s) SLTM acknowledged, Link test passed", link.getName()));

            }

        }



        /**

         * Sends SLTM message using this link.

         * 

         * @param timeout  the amount of time in millesecond for awaiting response.

         */

        public void ping(long timeout) {

            //prepearing test message

            

            writeRoutingLabel(sltm, 0x01, ni, link.getSls(), dpc, opc);

            //sltm[0] = (byte) 0x01; 

            sltm[5] = 0x11;

            sltm[6] = (byte) (SLTM_PATTERN.length << 4);

            System.arraycopy(SLTM_PATTERN, 0, sltm, 7, SLTM_PATTERN.length);



            //sending test message

            link.send(sltm, sltm.length);



            //incremeting number of tries.

            tryCount++;



            //scheduling timeout

            executor.schedule(this, (int)(timeout * 1000));

            if (logger.isDebugEnabled()) {

                logger.debug(String.format("(%s) SLTM sent, try number = %d", link.getName(), tryCount));

            }

        }

        

        public void perform() {

            switch (tryCount) {

                case 0:

                    //sending first test message

                    ping(Mtp3.TIMEOUT_T1_SLTM);

                    break;

                case 1:

                    //first message was not answered, sending second

                    ping(Mtp3.TIMEOUT_T1_SLTM);

                    break;

                case 2:

                    if (logger.isDebugEnabled()) {

                        logger.debug(String.format("(%s) SLTM message was not acknowledged, Link failed", link.getName()));

                    }

                    //second message was not answered, report failure

                    linkFailed(link);

            }

        }

    }



    // //////////////////

    // Helper methods //

    // //////////////////

    public static final int dpc(byte[] sif, int shift) {

        int dpc = (sif[0 + shift] & 0xff | ((sif[1 + shift] & 0x3f) << 8));

        return dpc;

    }



    public static final int opc(byte[] sif, int shift) {

        int opc = ((sif[1 + shift] & 0xC0) >> 6) | ((sif[2 + shift] & 0xff) << 2) | ((sif[3 + shift] & 0x0f) << 10);

        return opc;

    }



    public static final int sls(byte[] sif, int shift) {

        int sls = (sif[3 + shift] & 0xf0) >>> 4;

        return sls;

    }    



    public static final int si(byte[] data) {

        

        int serviceIndicator = data[0] & 0x0f;

        return serviceIndicator;

    }

    

    public static final int ssi(byte[] data) {

        //see Q.704.14.2 

        int subserviceIndicator = (data[0] >> 4) & 0x0F;

        return subserviceIndicator;

    }

    

    public static void writeRoutingLabel(byte[] data, int si, int ssi, int sls, int dpc, int opc) {

        //see Q.704.14.2 

        writeRoutingLabel(0,data, si, ssi, sls, dpc, opc);

        

    }   

    public static void writeRoutingLabel(int shift, byte[] data, int si, int ssi, int sls, int dpc, int opc) {

        //see Q.704.14.2 

        data[0+shift] = (byte) (((ssi & 0x0F) << 4) | (si & 0x0F));

        data[1+shift] = (byte) dpc;

        data[2+shift] = (byte) (((dpc >> 8) & 0x3F) | ((opc & 0x03) << 6));

        data[3+shift] = (byte) (opc >> 2);

        data[4+shift] = (byte) (((opc >> 10) & 0x0F) | ((sls & 0x0F) << 4));

        

    } 

}