  Run-time variables
  ------------------

  The run-time variables defined by the server are:

     %{Attribute-Name}               The value of the given Attribute-Name
                                     in the request packet

     %{request:Attribute-Name}       The value of value the given
                                     Attribute-Name in the request packet
     %{reply:Attribute-Name}         The value of the given Attribute-Name
                                     in the reply packet
     %{proxy-request:Attribute-Name} The value of the given Attribute-Name
                                     in the proxy request packet (if it exists)
     %{proxy-reply:Attribute-Name}   The value of the given Attribute-Name
                                     in the proxy reply packet (if it exists)

  The above variable expansions also support the meta-attribute
Packet-Type as well. See the RADIUS dictionary for details on its
values.
 
     %{check:Attribute-Name}         Corresponding value for Attribute-Name
                                     in check items for request
	

     %{config:section.subsection.item} Corresponding value in 'radiusd.conf'
                                       for the string value of that item.

  The %{config:...} variables should be used VERY carefully, as they
may leak secret information from your RADIUS server, if you use them
in reply attributes to the NAS!

  If your system supports regular expressions, then regular expression
matching defines other special variables, just like in Perl.

     %{0}	What the regular expression matched
     %{1}	The first group which matched
     %{2}	The second group which matched
     ...
     %{8}	The eight group which matched.

  These variables are defined during a regular expression match =~,
and only when the expression matches.  They are NOT defined for the
operator !~, or when =~ doesn't match.  Any use of =~ destroys all
previous values of %{0}..%{8}, but the variables.

  Some examples.

  %{User-Name}			 The string value of the User-Name attribute.
  %{proxy-reply:Framed-Protocol} The string value of the Framed-Protocol
				 attribute, from the proxy reply.
  %{config:modules.unix.passwd}  The string value of the 'passwd' configuration
				 item in the 'unix' module, in the 'modules'
				 section of radiusd.conf.

DEFAULT  User-Name =~ "^([^@]+)@(.*)"
	 All-That-Matched = `%{0}`
	 Just-The-User-Name = `%{1}`
	 Just-The-Realm-Name = `%{2}`


  The variables are used in dynamically translated strings.  Most of
the configuration entries in radiusd.conf (and related files) will do
dynamic string translation.  To do the same dynamic translation in a
RADIUS attribute (when pulling it from a database, or "users" file),
you must put the string into an back-quoted string:

       Session-Timeout = `%{expr: 2 + 3}`

  To do the dynamic translation in the 'radiusd.conf' (or some other
configuration files), just use the variable as-is.  See 'radiusd.conf'
for examples.


  Conditional syntax
  --------------------

  Additionally, you can use conditional syntax similar to ${foo:-bar} as
defined in 'sh'.  For example:

  1.  %{Foo:-bar}
    When attribute Foo is set:    returns value of Foo
    When attribute Foo is unset:  returns literal string 'bar'

  2.  %{Foo:-%{Bar}}
    When attribute Foo is set:    returns value of attribute Foo
    When attribute Foo is unset:  returns value of attribute Bar (if any)

  3.  %{Foo:-%{Bar:-baz}}
    When attribute Foo is set:    returns value of attribute Foo
    When attribute Foo is unset:  returns value of attribute Bar (if any)
    When attribute Bar is unset:  returns literal string 'baz'


  Multiple-valued attributes
  --------------------------

     %{Attribute-Name[index]}
	Reference the N'th occurance of the given attribute.  The
	indexes start at zero.  This feature is NOT available for
	non-attribute dynamic translations, like %{sql:...}.

 	e.g. %{User-Name[0]} is the same as %{User-Name}
	e.g. %{Cisco-AVPair[2]} references the value of the *third*
	     Cisco-AVPair attribute (if it exists) in the request
	     packet,


  Attributes as environment variables in executed programs
  --------------------------------------------------------

  When calling an external program (e.g. from 'rlm_exec' module),
these variables can be passed on the command line to the program.
In addition, the server places all of the attributes in the RADIUS
request into environment variables for the external program. The
variables are renamed under the following rules:

  1.  All letters are made upper-case.

  2.  All hyphens '-' are turned into underscores '_'

so the attribute User-Name can be passed on the command line to the
program as %{User-Name}, or used inside the program as the environment
variable USER_NAME (or $USER_NAME for shell scripts).

  If you want to see the list of all of the variables, try adding a
line 'printenv > /tmp/exec-program-wait' to the script.  Then look in
the file for a complete list of variables.


  One-character variables
  -----------------------

  The following one-character variables are also defined.  However, they
are duplicates of the previous general cases, and are only provided
for backwards compatibility.  They WILL BE removed in a future
release.  They also do NOT permit the use of conditional syntax
(':-'), as described above.


    Variable  Description		  Proper Equivalent
    --------  -----------		  ----------------
     %a       Protocol (SLIP/PPP)	  %{Framed-Protocol}
     %c       Callback-Number		  %{Callback-Number}
     %d       request day (DD)
     %f       Framed IP address		  %{Framed-IP-Address}
     %i       Calling Station ID	  %{Calling-Station-Id}
     %l       request timestamp
     %m       request month (MM)
     %n       NAS IP address		  %{NAS-IP-Address}
     %p       Port number		  %{NAS-Port}
     %s       Speed (PW_CONNECT_INFO)	  %{Connect-Info}
     %t       request in ctime format
     %u       User name			  %{User-Name}
     %A       radacct_dir		  %{config:radacctdir}
     %C       clientname
     %D       request date (YYYYMMDD)
     %H	      request hour
     %L       radlog_dir		  %{config:logdir}
     %M       MTU			  %{Framed-MTU}
     %R       radius_dir		  %{config:raddbdir}
     %S       request timestamp
                in SQL format
     %T       request timestamp
                in database format
     %U       Stripped User name	  %{Stripped-User-Name}
     %V       Request-Authenticator
                (Verified/None)
     %Y       request year (YYYY)
     %Z       All request attributes
               except password
               (must have a big buffer)

 $Id$
