rlm_expr

Synopsis

The expr module implements math expressions in dynamically expanded strings. It also implements a number of other useful expansions.

Default configuration

Processing Sections

None.

Expansions

The expr module implements a number of expansions.

expr

Syntax: %{expr: …}
Contents: The contents of the expansion are a series of mathematical expressions. The output of the expansion is the result of evaluating the mathematical expression.
: Normal math operators are supported as shown in the table below.

Table 1. Mathematical operators
Operator	Meaning
+	Addition
-	Subtraction
/	Division
*	Multiplication
%%	Remainder
<<	Left shift
>>	Right shift
&	Bitwise "and"
\|	Bitwise "or"
^	Power
(	Open bracket, start sub-expression
)	Close bracket, end sub-expression

: All calculations are done via unsigned 64-bit integers. Floating point is not supported. All integers are assumed to be base 10. Hexadecimal numbers can be used by preceding them with 0x, such as with 0xabcdef.
: .Example

%{expr: 1 ` 2 ` (2^3) + 0xad}

escape

Syntax: %{escape: …}
Contents: The contents of the expansion are a string. The output of the expansion is the input string with the safe_characters escaped as =HH, where HH is the hex value of the character.

rand

Syntax: %{rand: …}
Contents: The contents of the expansion are an integer that is the limit for the random number generation. The output of the expansion is a random number that is between 0 and that limit.
: The limit must be greater than zero and less than 2^30 (about one billion).

randstr

Syntax: %{randstr: …}
Contents: The contents of the expansion are a pattern describing the random string to generate. The output of the expansion is the random string.
: The input pattern is described by the following table. Each modifier can take a numeric prefix, to create more than one character of output. e.g. %{randstr:5n} will create 5 numbers. The repetition is limited to 100. Any more than that is ignored.

Table 2. Patterns
Character	Meaning
!	Punctuation. One of !"#$%&'()*+,-./:;<⇒?@[\\]^_`{\|}~
.	Alphanumeric plus punctuation
a	Alphanumeric [a-zA-Z0-9]
c	Latin lowercase character [a-z]
C	Latin uppercase character [A-Z]
h	two hex digits [0-f][0-f]
n	Numbers [0-9]
s	Salt [a-zA-Z0-9./]

tolower

Syntax: %{tolower: …}
Contents: The contents of the expansion are a string. The output of the expansion is the input string, converted to lowercase.

toupper

Syntax: %{toupper: …}
Contents: The contents of the expansion are a string. The output of the expansion is the input string, converted to uppercase.

urlquote

Syntax: %{urlquote: …}
Contents: The contents of the expansion are a string. The output of the expansion is the input string with the safe_characters escaped as %HH, where HH is the hex value of the character.

md5

Syntax: %{md5: …}
Contents: The contents of the expansion are either a string or a reference to an attribute. The output of the expansion is the MD5 hash of the input string, printed as 32 hexadecimal digits.

Example

%{md5:Hi, Mom}
%{md5:&User-Name}

: The attribute reference syntax allows the expansion to take the MD5 hash of binary data. If attribute references were not allowed, then the MD5 expansion would be required to hash the printable form of the binary data, which is not the same as hashing the binary data.

sha1

Syntax: %{sha1: …}
Contents: The contents of the expansion are a string. The output of the expansion is the sha1 hash of the string. This expansion otherwise operates the same as the md5 one.

sha256

Syntax: %{sha256: …}
Contents: The contents of the expansion are a string. The output of the expansion is the sha256 hash of the string. This expansion otherwise operates the same as the md5 one.

sha512

Syntax: %{sha512: …}
Contents: The contents of the expansion are a string. The output of the expansion is the sha512 hash of the string. This expansion otherwise operates the same as the md5 one.

base64

Syntax: %{base64: …}
Contents: The contents of the expansion are a string. The output of the expansion is the string converted to base64. This expansion supports attribute references, just like the md5 expansion.

base64tohex

Syntax: %{base64tohex: …}
Contents: The contents of the expansion are a base64 string. The output of the expansion is the string converted to hex digits. The digits are not preceded by any 0x characters.

lpad

Syntax: %{lpad:&Attribute-Reference length pad}
Contents: The contents of the expansion are 3 fields, with the third field being optional. The first field is an attribute references, e.g. &User-Name. The second is an integer specifying the size of the fixed-width field to produce, e.g. 7. The third field is a padding character, e.g. 0. If the the third field is omitted, then a space is used as the fill character.

Example

%{lpad:&User-Name 7}
%{lpad:&User-Name 7 x}
%{lpad:&reply:Filter-Id 7}

: The output of the expansion is a fixed-width string, composed of "length" characters, with the attribute printed to a string. If "length" is smaller than the length of the attribute string, the output is truncated to "length" characters. If "length" is equal to the length of the attribute string, the output is exactly the attribute string. If "length" is larger than the length of the attribute string, the output is filled to the left with the "pad" character.

Table 3. Example for User-Name = "test"
Input	Output
%{lpad:&User-Name 7}	`" test"`
%{lpad:&User-Name 2}	`"te"`
%{lpad:&User-Name 6 0}	`"00test"`

rpad

Syntax: %{rpad:&Attribute-Reference length pad}
Contents: The contents of the expansion are 3 fields, with the third field being optional. The first field is an attribute references, e.g. &User-Name. The second is an integer specifying the size of the fixed-width field to produce, e.g. 7. The third field is a padding character, e.g. 0. If the the third field is omitted, then a space is used as the fill character.

Example

%{rpad:&User-Name 7}
%{rpad:&User-Name 7 x}
%{rpad:&reply:Filter-Id 7}

: The output of the expansion is a fixed-width string, composed of "length" characters, with the attribute printed to a string. If "length" is smaller than the length of the attribute string, the output is truncated to "length" characters. If "length" is equal to the length of the attribute string, the output is exactly the attribute string. If "length" is larger than the length of the attribute string, the output is filled to the right with the "pad" character.

Table 4. Example for User-Name = "test"
Input	Output
%{rpad:&User-Name 7}	`"test "`
%{rpad:&User-Name 2}	`"te"`
%{rpad:&User-Name 6 0}	`"test00"`

Directives

safe-characters

Syntax: safe-characters = string
Default: @abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.-: /_
Description: Characters that will not be encoded by the %\{encode:…} expansion.