etherswitch.java

一个小型网络仿真器的实现

    }
  }

  private void sw_my_receive(SimEvent e) {
    EtherFrame frame=(EtherFrame)e.getParams();
    ForwardEntry fe;
    SimComponent src=(SimComponent)e.getSource();
    Port voport=null;
    long ticks;

    fe=(ForwardEntry)sw_forward_table.get(new Long(frame.dest_mac));
    if(fe==null) { //no forwarding info, must broadcast!
      sw_broadcast(frame,src);
    }
    else {
      voport=(Port)voports.get(fe.to_link);
      voport.spq.add(frame);
      voport.spq_size+= (frame.length()>>3);

      if(voport.spq.size()==1) { //must schedule a processing slot if spq previously empty
        ticks=SimClock.USec2Tick(frame.length() / (double)sw_speed.getValue());
        theSim.enqueue(new SimEvent(MY_SLOT_TIME,this,this,theSim.now()+ticks,voport));
      }
    }

  //test source mac
    fe=(ForwardEntry)sw_forward_table.get(new Long(frame.src_mac));
    if(fe==null) { //no entry yet, than add one
      fe=new ForwardEntry();
      fe.dest_mac=frame.src_mac;
      fe.to_link=src;
      sw_forward_table.put(new Long(fe.dest_mac),fe);
    }
  }

//////////////////// SimCommand services //////////////////////////

  private transient SimGUI theGUI=null;

  public SimCommand querySimCommand(int selectedCount) {
    if(selectedCount==1) return this; //only allow this when exactly one
                                      //  switch is selected
    else return null;
  }

  public void analyzerUp(Analyzer a) {
    analyzer=a;
  }

  public void analyzerDown(Analyzer a) {
    analyzer=null;
  }

  public java.util.List getCommand(Sim aSim,SimGUI aGUI) {
    java.util.List cmd=new java.util.ArrayList();

    JMenuItem menuItem=new JMenuItem("Set IP Subnet");
    menuItem.addActionListener(this);
    cmd.add(menuItem);

    //analyzer
    if(analyzer!=null) cmd.addAll(analyzer.getCommand(aSim,aGUI));
    else cmd.addAll((new Analyzer(this,this)).getCommand(aSim,aGUI));

    theGUI=aGUI;

    return cmd;
  }

  private boolean checkRunning() {
    if(theSim.isRunning()) {
      JOptionPane.showMessageDialog(theGUI.getMainFrame(),"Simulation is running!",
        "Command not allowed",JOptionPane.WARNING_MESSAGE);
      return false;
    }
    return true;
  }

  private class SubnetDialogListener implements ActionListener,FocusListener {
    JDialog dialog=null;
    JTextField txtIP=null, txtMask=null;
    JComboBox comps=null;
    JButton btnOK=null, btnCancel=null;
    java.util.List links=null;
    java.util.List routers=null;
    int newIP,newMask,subnet_size=0;

    private boolean ipOK() {
      String ip=txtIP.getText()+".";
      int thisIndex,lastIndex=0;
      int quad;
      newIP=0;
      for(int i=0;i<4;i++) {
        thisIndex=ip.indexOf('.',lastIndex);
        if(thisIndex==-1) return false;
        try {
          quad=Integer.parseInt(ip.substring(lastIndex,thisIndex));
          if(quad<0 || quad>255) return false;
        } catch(NumberFormatException ex) {
          return false;
        }
        newIP<<=8;
        newIP|=quad;
        lastIndex=thisIndex+1;
      }
      return true;
    }
    private boolean maskOK() {
      String mask=txtMask.getText()+".";
      int thisIndex,lastIndex=0;
      int quad;
      newMask=0;
      for(int i=0;i<4;i++) {
        thisIndex=mask.indexOf('.',lastIndex);
        if(thisIndex==-1) return false;
        try {
          quad=Integer.parseInt(mask.substring(lastIndex,thisIndex));
          if(quad<0 || quad>255) return false;
        } catch(NumberFormatException ex) {
          return false;
        }
        newMask<<=8;
        newMask|=quad;
        lastIndex=thisIndex+1;
      }
      //verify mask, is there a better way?
      if(newMask==0 || newMask==0xffffffff) return true;
      if(newMask>0) return false; //must have leading one!
      mask=Integer.toBinaryString(newMask);
      int lastOne=mask.lastIndexOf('1');
      int firstZero=mask.indexOf('0');
      if(lastOne != firstZero-1) return false;

      subnet_size=(1<<(31-lastOne)) - 2;

      return true;
    }
    public void focusGained(FocusEvent e) {
      if(!txtIP.getText().equals("") && txtMask.getText().equals("")) {
        if(ipOK()) {
          int quad=(newIP>>24)&0xff;
          if(quad<128) txtMask.setText("255.0.0.0");
          else if(quad<192) txtMask.setText("255.255.0.0");
          else txtMask.setText("255.255.255.0");
          txtMask.setCaretPosition(0);
          txtMask.moveCaretPosition(txtMask.getText().length());
        }
      }
    }
    public void focusLost(FocusEvent e) {
    }
    public void actionPerformed(ActionEvent e) {
      if(e.getSource() == btnOK) {
        if(!ipOK()) {
          JOptionPane.showMessageDialog(null,"Not a valid IP address!","Error",
            JOptionPane.INFORMATION_MESSAGE);
          txtIP.requestFocus();
          return;
        }
        if(!maskOK()) {
          JOptionPane.showMessageDialog(null,"Not a valid net mask!","Error",
            JOptionPane.INFORMATION_MESSAGE);
          txtMask.requestFocus();
          return;
        }
        //check ip/mask combo
        if((newIP & newMask) != newIP) {
          JOptionPane.showMessageDialog(null,"Subnet IP and mask do not match!","Error",
            JOptionPane.INFORMATION_MESSAGE);
          return;
        }
        //check subnet size
        if(subnet_size < routers.size()) {
          JOptionPane.showMessageDialog(null,"Subnet size too small!","Error",
            JOptionPane.INFORMATION_MESSAGE);
          return;
        }

        //Good, now everyone is assigned an IP for this link
        int i;
        int gateway_index=comps.getSelectedIndex();
        int curIP=1;

        for(i=0;i<routers.size();i++) {
          SimComponent thiscomp=(SimComponent)routers.get(i);
          SimComponent thelink=(SimComponent)links.get(i);
          Object [] paramlist=new Object[3];
          if(i==gateway_index)
            paramlist[0]=new Integer(newIP | subnet_size);
          else
            paramlist[0]=new Integer(newIP | curIP++);
          paramlist[1]=new Integer(newMask);
          paramlist[2]=thelink;
          thiscomp.compInfo(IPRouter.SET_PORT_IP,null,paramlist);
        }

        //now add route entry to this subnet
        for(i=0;i<routers.size();i++) {
          SimComponent thiscomp=(SimComponent)routers.get(i);
          SimComponent thelink=(SimComponent)links.get(i);
          Object [] paramlist=new Object[5];
          paramlist[0]=new Integer(newIP);
          paramlist[1]=new Integer(newMask);
          paramlist[2]=new Integer(0);
          paramlist[3]=thelink;
          paramlist[4]="Static";
          thiscomp.compInfo(IPRouter.ADD_ROUTE_ENTRY,null,paramlist);
        }

        //if a gateway is selected, add the default route for everyone
        //  except the gateway itself
        if(gateway_index<routers.size()) {
          for(i=0;i<routers.size();i++) {
            if(i==gateway_index) continue; //skip the gateway itself

            SimComponent thiscomp=(SimComponent)routers.get(i);
            SimComponent thelink=(SimComponent)links.get(i);
            Object [] paramlist=new Object[5];
            paramlist[0]=new Integer(0);
            paramlist[1]=new Integer(0);
            paramlist[2]=new Integer(newIP | subnet_size);
            paramlist[3]=thelink;
            paramlist[4]="Static";
            thiscomp.compInfo(IPRouter.ADD_ROUTE_ENTRY,null,paramlist);
          }
        }

        //Done!

        dialog.dispose();
        return;
      }
      else  {
        dialog.dispose();
        return;
      }
    }
  }

  private void getConnectedRouters(java.util.List links,java.util.List comps) {
    java.util.Iterator i=voports.values().iterator();
    while(i.hasNext()) {
      Port voport=(Port)i.next();
      SimComponent otherend=(SimComponent)voport.to_link.compInfo(GenericLink.GET_OTHER_END,this,this);
      if(otherend==null) continue;
      if(!otherend.getCompClass().equals("Router")) continue;
      links.add(voport.to_link);
      comps.add(otherend);
    }
  }

  private String [] getRouterNames(java.util.List routers) {
    String [] names=new String[routers.size()+1];
    int i;
    for(i=0;i<routers.size();i++) {
      names[i]=((SimComponent)routers.get(i)).getName();
    }
    names[i]="None";
    return names;
  }

  public void actionPerformed(ActionEvent e) {
    if(e.getActionCommand().equals("Set IP Subnet")) {
      if(!checkRunning()) return;

      SubnetDialogListener listener=new SubnetDialogListener();
      listener.links=new java.util.ArrayList();
      listener.routers=new java.util.ArrayList();
      getConnectedRouters(listener.links,listener.routers);

      if(listener.links.size()<2) {
        JOptionPane.showMessageDialog(theGUI.getMainFrame(),"Subnet must have at least two hosts/routers.",
          "Error",JOptionPane.INFORMATION_MESSAGE);
        return;
      }

      JDialog dialog=new JDialog(theGUI.getMainFrame(),"Set IP Subnet",true);
      dialog.getContentPane().setLayout(new GridLayout(4,1));

      JPanel aPanel=new JPanel();
      aPanel.add(new JLabel("Subnet IP:"));
      aPanel.add(listener.txtIP=new JTextField(10));
      dialog.getContentPane().add(aPanel);

      aPanel=new JPanel();
      aPanel.add(new JLabel("Subnet Mask:"));
      aPanel.add(listener.txtMask=new JTextField(10));
      dialog.getContentPane().add(aPanel);

      aPanel=new JPanel();
      aPanel.add(new JLabel("Gateway:"));
      JComboBox comps=new JComboBox(getRouterNames(listener.routers));
      comps.setSelectedIndex(listener.routers.size()); //select last item "None" by default
      aPanel.add(listener.comps=comps);
      dialog.getContentPane().add(aPanel);

      aPanel=new JPanel();
      aPanel.add(listener.btnOK=new JButton("OK"));
      aPanel.add(listener.btnCancel=new JButton("Cancel"));
      dialog.getContentPane().add(aPanel);
      dialog.getRootPane().setDefaultButton(listener.btnOK);
      listener.btnOK.addActionListener(listener);
      listener.btnCancel.addActionListener(listener);
      listener.txtMask.addFocusListener(listener);
      listener.dialog=dialog;

      dialog.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);

      dialog.pack();
      Dimension ddim=dialog.getPreferredSize();
      Dimension sdim=Toolkit.getDefaultToolkit().getScreenSize();
      dialog.setLocation((sdim.width-ddim.width)/2,(sdim.height-ddim.height)/2);
      dialog.show();
    }
  }
}