VPLS_Loop_Snapshot

version 1.0;

/*
- MAC Location Aware - VPLS Loop Detection
- Current Junos Release does have loop dection mechanisim.
- Which generates Syslog and capture the move in Mac-move-buffer
- But NO action mechansim is avaiable that could shutdown the
- Looped Logical Interface.
-
- This is work around script that use snapshot of VPLS Mac table 
- and then during the loop event uses this snapshot to coreleate the MAC 
- original location and shutdown only the looped interface unit.
-
- Script by : 
- Neeraj Shetty , System Engineer.
- E-mail : nshetty@juniper.net
- Copyright (c) 2005, Juniper Networks, Inc.
- All rights reserved.
-
 */
 
ns junos = "http://xml.juniper.net/junos/*/junos";
ns xnm = "http://xml.juniper.net/xnm/1.1/xnm";
ns jcs = "http://xml.juniper.net/junos/commit-scripts/1.0";
ns date = "http://exslt.org/dates-and-times";

import "../import/junos.xsl";

match / {
    <op-script-output> {
    
    /* Dampens the Script to Run Once every Minute */    
    if (jcs:dampen ("VPLS_Loop",1,1)){
        var $file = document ("/var/tmp/mac/vpls_mac_snapshot.xml");
    
        /* Check for Empty Mac-table Condition */    
        if (jcs:empty( $file//*[local-name() == "l2ald-mac-entry"] )){
            var $emt = "empty";
            var $mac = "empty";
            call syslog ($mac,$emt);
        }
        for-each ($file//*[local-name() == "l2ald-mac-entry"]) {
           var $db = ./*[local-name() == "l2-mac-bridging-domain"];
           var $mac = ./*[local-name() == "l2-mac-address"];
           var $intf = ./*[local-name() == "l2-mac-logical-interface"];
           if(starts-with($intf,"lsi")) {
                var $emt = "full";
               call syslog ($mac,$emt);
           }
        }
      }
    }
}

template syslog ($mac,$emt) {

    var $mac-move-rpc = {
      <get-l2-learning-mac-move-buffer-information> {
        <extensive>;
      }
    }
    var $res = jcs:invoke($mac-move-rpc);
    for-each ($res/l2ald-mac-move-entry){
                var $from = l2ald-mac-move-from-ifl;
                var $to = l2ald-mac-move-to-ifl;
                var $add = l2ald-mac-address;
        
                /* Compares the Last Entry in L2-Learning mac-move-buffer */
        
                if ( position() == last() ) {
                    if (not (starts-with($to,"lsi"))){
            
               /* Match the Mac in Mac-move-buffer and Snapshot */
               /* Disabled the Physical Interface incase of Empty Mac Table (Newly Provisioned Instance) */
                      
                        if ($mac == $add || $emt == "empty")  {
            
                          /* Split the TO interface into Physical (IFD) and Unit (IFL) */
              
                          var $pattern = "[.]";
                          var $substrings = jcs:split($pattern, $to);
                          var $physical = $substrings[1];
                          var $unit = $substrings[2];
              
                          /* Generates Syslog to Notify Loop Condition */
                
                          expr jcs:syslog("daemon.debug"," [VPLS-LOOP-DETECTED]: Interface ", $physical, ".", $unit, " shutdown due to loop.");

                          /* Clear l2-learning mac-move-buffer - Reducdes Number of lookup on Spawned Instance of Script */
              
                          var $clm-rpc = <command> "clear l2-learning mac-move-buffer";
                          var $clm = jcs:invoke( $clm-rpc );
              
                          /* Configuration to be Disable */
                            
                           var $config-change = <configuration> {
                                 <interfaces>  {
                                     <interface>  {
                                      <name> $physical;
                                            <unit> {
                                                <name> $unit;
                                                call jcs:emit-comment();
                                                <disable>;
                                            }
                                      }
                                }
                            }
                
                            /* Disable the Looped Unit (IFL) - Edit Private Mode is used */
                
                            var $connection = jcs:open();
                            var $config-private =   <open-configuration> {
                                  <private>;
                             }
                            var $private-results = jcs:execute( $connection, $config-private );
                            var $load-configuration =   <load-configuration> {
                                   copy-of $config-change;
                            }
                            var $load-results = jcs:execute( $connection, $load-configuration );
                            var $commit-configuration = <commit-configuration>;
                            var $commit-results = jcs:execute( $connection, $commit-configuration );
                            var $close-private = <close-configuration>;
                            var $close-configuration-results = jcs:execute( $connection, $close-private );
                            var $close-results = jcs:close( $connection );

                        }
                    }
             }
    }

/* Sleep for 30 Second */

expr jcs:sleep(30);

/* Clear l2-learning mac-move-buffer */

var $clm-rpc1 = <command> "clear l2-learning mac-move-buffer";
var $clm1 = jcs:invoke( $clm-rpc1 );

/* Generates Syslog on ALL the nodes that the script Runs */

expr jcs:syslog("daemon.debug","VPLS Loop Script Cleared l2-mac-move-buffer.");

}