Some statements in the configuration files need to use the actual values of the attributes supplied with the request. These are:
Exec-Program and Exec-Program-Wait assignments in ‘users’ database
In these statements the following macros are replaced by the value of corresponding attributes:
%Cnum(num is a decimal number). This variable is replaced by the value of attribute number `num'. The attribute is looked up in the incoming request pairlist.
%C{attr-name}This is replaced by the value of attribute named `attr-name'. The attribute is looked up in the incoming request pairlist.
%Rnum(num is a decimal number). This variable is replaced by the value of attribute number `num'. The attribute is looked up in the reply pairlist.
%R{attr-name}This is replaced by the value of attribute named `attr-name'. The attribute is looked up in the reply pairlist.
%DThis is replaced by current date/time (localtime).
%GThis is replaced by current date/time in GMT.
The exact substitution procedure varies depending on the type
of the attribute referenced by macro. If the attribute is of
string or date type, radiusd first checks if the resulting
substitution should be quoted. It does so by looking at the character
immediately preceeding ‘%’. If it is a single or double quote,
then radiusd assumes the macro must be quoted and replaces it
by an appropriately modified attribute value. The purpose of the
modification is to ensure that no characters within the expanded
string would conflict with the quoting characters. In particular,
radiusd searches the attribute value for any of the
characters ‘\’, ‘'’, ‘"’ and prepends
a ‘\’ to any occurrence of these. For example, suppose that
attribute NAS-Identifier has the value ‘A "new" host’.
Then:
nasid=%C{NAS-Identifier} → nasid=A "new" host
nasid="%C{NAS-Identifier}" → nasid="A \"new\" host"
nasid=%\C{NAS-Identifier} → nasid=A \"new\" host
The last example illustrates the use of backslash character to force string quoting in the absense of explicit quotation marks.
If an integer attribute reference is quoted, radiusd looks
up the string translation of its value in the dictionary
(see section VALUE Statement) and uses this string as a replacement. If no
translation is found, the numeric value is used. The following
example assumes that the value of Acct-Terminate-Cause
attribute is 10:
reason=%C{Acct-Terminate-Cause} → reason=10
reason='%C{Acct-Terminate-Cause}' → reason='NAS-Request'
reason=%\C{Acct-Terminate-Cause} → reason=NAS-Request
Again, a backslash after percent sign can be used to force dictionary lookup.
The “‘{}’ form” allows to specify default value for the substitution. The default value will be used when no such attribute is encountered in the pairlist. The syntax for specifying the default value resembles that of shell environment variables.
The substitution %C{attr-name:-defval} is expanded
to the value of attr-name attribute, if it is present in the
request pairlist, and to defval otherwise. For example:
%C{Acct-Session-Time:-0}
will return the value of Acct-Session-Time attribute or 0 if it doesn't exist in the request pairlist.
The substitution %C{attr-name:=defval} is expanded
to the value of attr-name attribute. If this attribute is not
present in the request pairlist, it will be created and assigned the
value defval. E.g.:
%C{Acct-Session-Time:=0}
The substitution %C{attr-name:?message} is expanded
to the value of attr-name attribute, if it is present. Otherwise
the diagnostic message “attr-name: message” is issued to
the log error channel, and string “message” is returned.
The substitution %C{attr-name:+retval} is expanded
to empty string if the attribute attr-name is present in the
referenced pairlist. Otherwise it is expanded to retval.
You can also use the following shortcuts:
%pPort number
%nNAS IP address
%fFramed IP address
%uUser name
%cCallback-Number
%iCalling-Station-Id
%tMTU
%aProtocol (SLIP/PPP)
%sSpeed (Connect-Info attribute)
This document was generated by Sergey Poznyakoff on December, 6 2008 using texi2html 1.78.