[RADIATOR] FarmChildHook to rotate AuthPort, AcctPort and DBSource

[Christian Kratzer]

Hi,

I would like to contribute following snippet I use for FarmChildHook EAP environments where I have a backend radius behind HASHBALANCE or similar.

The hook shows how to accomplish following:

1. Add farminstance to Acctport and Authport of the base config and reopen ports.

This is nice for setting up a backend with multiple ports where to point HASHBALANCE at.

2. Walk over all authby in the config and hash the list of db credentials.

This way you can configure multiple databases in the main config and the hook picks a differnt database for each child.

The code could easily be modified to rotate the list of databases by the child number for a similar effect whilst keeping failover capability to the other databases.

3. Also note the rather high number fo MaxFailedRequests in HASHBALANCE.  I saw the backends get marked bad instantly when activating this in a high load enviroment with a low number fo MaxFailedRequests.  I never quite found out why but assume this was due to interfering with in progress EAP transactions.  A value of 10 keeps the hashbalance happy until the backend really dies.  YMMW of course.

Feel free to add this to the radiator goodies directory.

Greetings and have fun
Christian Kratzer
CK Software GmbH


How to use in the fronend:
--------------------------

     <Handler>
 	<AuthBy HASHBALANCE>
 	    FailureBackoffTime 60
 	    Secret mysecret
 	    MaxFailedRequests 10
 	    Retries 0

 	    <Host ::1>
 		AuthPort 10001
 		AcctPort 20001
 	    </Host>
 	    <Host ::1>
 		AuthPort 10002
 		AcctPort 20002
 	    </Host>
 	    <Host ::1>
 		AuthPort 10003
 		AcctPort 20003
 	    </Host>
 	    ...
 	</AuthBy>
     </Handler>

How to use in the backend:
--------------------------

     AuthPort      10000
     AcctPort	  20000
     FarmSize      4
     FarmChildHook file:"%D/hooks/farmchild.hook"

     <AuthBy SQL>
 	Identifier	SQLauth

 	DBSource        db1
 	DBUsername      user
 	DBAuth          pass

 	DBSource        db2
 	DBUsername      user
 	DBAuth          pass

 	...
     </AuthBy>

     <Handler>
 	AuthBy 		SQLauth
     </Handler>


hooks/farmchild.hook:
---------------------


# ------------------------------------------------------------------------
# FarmChildHook
# close and reopen AuthPort and AcctPort in farmchilds and adds
# farmInstance to the port number
# this also works correctly when farmInstance is >=10 when AuthPort
# 100%O fails.
#
# AuthPort      10000
# AcctPort
# FarmSize      4
# FarmChildHook file:"%D/hooks/farmchild.hook"
#
sub
{
     my $radius_server = $main::config->{radius_server};

     # add farmInstance to AuthPort
     my $authport = Radius::Util::format_special($main::config->{AuthPort});
     if($authport) {
         $authport=$authport + $main::farmInstance;
         &main::log($main::LOG_INFO, "farmchild.hook: AuthPort: $authport");
         $radius_server->{'AuthPort'} = $authport;
     }

     # add farmInstance to AcctPort
     my $acctport = Radius::Util::format_special($main::config->{AcctPort});
     if($acctport) {
         $acctport=$acctport + $main::farmInstance;
         &main::log($main::LOG_INFO, "farmchild.hook: AcctPort: $acctport");
         $radius_server->{'AcctPort'} = $acctport;
     }

     # repoen auth and acct ports if needed
     if($authport || $acctport) {
         &main::log($main::LOG_INFO, "farmchild.hook: repoen ports");
         $radius_server->close_sockets();
         $radius_server->create_ports();
     }

     # walk over all AuthBy and Hash database credentials by farmInstance
     foreach my $auth (@{$main::config->{AuthBy}}) {
        my $id = $auth->{Identifier};
        foreach my $key (qw(DBSource DBUsername DBAuth)) {
            if ($auth->{$key}) {
                my $database_count = @{$auth->{$key}};
                $auth->{$key} = [ $auth->{$key}[ ($main::farmInstance-1)%$database_count ] ];
                &main::log($main::LOG_INFO, "farmchild.hook: AuthBy: $id, $key: ".$auth->{$key}[0] );
            }
        }
     }

     return;
}


-- 
Christian Kratzer                   CK Software GmbH
Email:   ck at cksoft.de               Wildberger Weg 24/2
Phone:   +49 7032 893 997 - 0       D-71126 Gaeufelden
Fax:     +49 7032 893 997 - 9       HRB 245288, Amtsgericht Stuttgart
Mobile:  +49 171 1947 843           Geschaeftsfuehrer: Christian Kratzer
Web:     http://www.cksoft.de/