(RADIATOR) Proposal for new config keywords

[Frederic Olivie]

Some users might want to lighten up the load on their sessions SQL
table. On a typical ADSL setup, the following scenario occurs :
- One auth ticket sent by the TELCO for it's local BAS -> DELETE
- One auth ticket sent by our own BAS -> DELETE
- One session start ticket sent by the TELCO's BAS -> DELETE / INSERT
- One session stop ticket sent by our BAS -> DELETE / INSERT

- Then, the normal Stop tickets mechanism which we don't touch.

This makes a total of 4 DELETEs + 2 INSERTs.

I propose the following mechanism :

1) As the Auth ticket will be followed by a Start ticket, the first
delete is made optional. The only case where this would be a problem
in the current behavior of radiator would be the following one :
- You use the simultaneous sessions limit (MaxSessions) feature
- User foo is disconnected the hard way and no Stop ticket is received.
- Use foo reconnects on exactly the same NAS/NASPORT and nobody has
  reconnected on it before him.

This is most unlikely to happen, and even if I did not do it, it would
be pretty simple to add a test to SessSQL's exceeded function to test
for same NAS/NASPORT before incrementing $count.

2) As some databases can do it easily (MySQL is one), the DELETE/INSERT
mechanism can be replaced by a single REPLACE INTO which replaces the
entry identified by the table's primary key (fine if your accounting
table has a primary key on the NAS/NASPORT pair), and inserts it if
it does not exist.

I added two flags to the SessSQL handler :

- DontDeleteOnAuth
- DontDeleteBeforeAdd

The first one is pretty straightforward, but the second one implies
that the user configures his instance of radiator to make a "replace
into" instead of an insert. e.g :

<SessionDatabase SQL>
	[... cut some stuff ...]
	DontDeleteBeforeAdd

        AddQuery        replace into RADONLINE (USERNAME, NASIDENTIFIER,
NASPORT, ACCTSESSIONID, TIME_STAMP, FRAMEDIPADDRESS, NASPORTTYPE,
SERVICETYPE) values ('%u', '%N', 0%{NAS-Port}, '%{Acct-Session-Id}',
%{Timestamp}, '%{Framed-IP-Address}', '%{NAS-Port-Type}',
'%{Service-Type}')

</SessionDatabase>

This also means that the primary key on the table is based on :
NASIDENTIFIER/NASPORT.

As a result of using those two flags, and in the case we are
talking about above, we go from :

4 DELETEs + 2 INSERTs.

to :

2 "REPLACE INTO"

Which is much, much faster because radiator only has 2 queries to
run (and wait a return for), and because the database backend has
very limited locking involved.

Modem sessions handling meet the same situation but we only loose
one DELETE.

The patch is pretty simple and involves only two files :
(The bug correction I sent earlier is not included in this diff.
It's based on pure 3.1 code).

*** Handler.pm	Tue Aug 27 21:54:28 2002
--- Handler.pm.patched	Wed Aug 28 15:37:10 2002
***************
*** 188,195 ****
      if ($p->code eq 'Access-Request')
      {
  	# If we lost a Stop for this port, clean up the session database
  	$sessdb->delete($original_username, $nas_id, $nas_port, $p, 
! 			$session_id, $framed_ip_address);
  
  	# Issue a denial and bomb out
  	return $self->handlerResult($p, $main::REJECT, 'MaxSessions
exceeded')
--- 188,196 ----
      if ($p->code eq 'Access-Request')
      {
  	# If we lost a Stop for this port, clean up the session database
+ 	# if flag "DontDeleteOnAUth" is not present.
  	$sessdb->delete($original_username, $nas_id, $nas_port, $p, 
! 			$session_id, $framed_ip_address) if (!defined
$sessdb->{DontDeleteOnAuth}) ;
  
  	# Issue a denial and bomb out
  	return $self->handlerResult($p, $main::REJECT, 'MaxSessions
exceeded')


*** SessSQL.pm	Tue Aug 27 22:03:57 2002
--- SessSQL.pm.patched	Wed Aug 28 16:19:41 2002
***************
*** 21,27 ****
       'DeleteQuery'           => 'string',
       'ClearNasQuery'         => 'string',
       'CountQuery'            => 'string',
!      'CountNasSessionsQuery' => 'string'
       );
  
  #####################################################################
--- 21,29 ----
       'DeleteQuery'           => 'string',
       'ClearNasQuery'         => 'string',
       'CountQuery'            => 'string',
!      'CountNasSessionsQuery' => 'string',
!      'DontDeleteBeforeAdd'   => 'flag',
!      'DontDeleteOnAuth'      => 'flag'
       );
  
  #####################################################################
***************
*** 61,69 ****
  
      $self->log($main::LOG_DEBUG, 
  	       "$self->{Identifier} Adding session for $name, $nas_id,
$nas_port", $p);
!     if ($self->{DeleteQuery})
      {
  	# Delete any existing session on this port first: its clearly defunct
  	$self->do(&Radius::Util::format_special
  		  ($self->{DeleteQuery}, $p, undef, 
  		   $name, $nas_id, $nas_port));
--- 63,72 ----
  
      $self->log($main::LOG_DEBUG, 
  	       "$self->{Identifier} Adding session for $name, $nas_id,
$nas_port", $p);
!     if (!defined $self->{DontDeleteBeforeAdd} && $self->{DeleteQuery})
      {
  	# Delete any existing session on this port first: its clearly defunct
+ 	# Don't do it if "DontDeleteBeforeAdd" flag is on.
  	$self->do(&Radius::Util::format_special
  		  ($self->{DeleteQuery}, $p, undef, 
  		   $name, $nas_id, $nas_port));

--
Frédéric Olivié (Alf)
Mailto: alf at club-internet.fr
Phoneto: +33 603 03 33 50

Very funny Scotty... Now beam down my clothes (Capt. James T. Kirk.
Starship Enterprise).
===
Archive at http://www.open.com.au/archives/radiator/
Announcements on radiator-announce at open.com.au
To unsubscribe, email 'majordomo at open.com.au' with
'unsubscribe radiator' in the body of the message.