Comparisons
lhs OP rhsThe most common use-case for conditions is to perform comparisons.
The lhs and rhs of a conditional comparison can be
&Attribute-Name or data. The
the OP is an operator, commonly == or <=. It is used to
control how the two other portions of the condition are compared.
The Comparison Operators
The comparison operators are given below.
| Operator | Description |
|---|---|
< |
less than |
<= |
less than or equals |
== |
equals, with automatic type casting |
!= |
not equals, with automatic type casting |
=== |
equals, but both operands have to be of the same type |
!== |
not equals, or they are not of the same type |
>= |
greater than or equals |
> |
greater than |
regular expression matches |
|
regular expression does not match |
The comparison operators perform type-specific comparisons. The
only exceptions are the regular expression operators,
which interpret the lhs as a printable string, and the rhs as a
regular expression.
Comparisons can be done across differing data types. Comparng a uint8 value to an uint16 value will "just work", as the data types will be automatically converted before any comparison is done.
IP Address Comparisons
The type-specific comparisons operate as expected for most data types. The only exception is data types that are IP addresses or IP address prefixes. For those data types, the comparisons are done via the following rules:
-
Any unqualified IP address is assumed to have a /32 prefix (IPv4) or a /128 prefix (IPv6).
-
If the prefixes of the left and right sides are equal, then the comparisons are performed on the IP address portion.
-
If the prefixes of the left and right sides are not equal, then the comparisons are performed as set membership checks.
The syntax allows conditions such as 192.0.2.1 < 192.0.2/24. This
condition will return true, as the IP address 192.0.2.1' is within
the network `192.0.2/24.
Casting
In some situations, it is useful to force the left side to be interpreted as a particular data type.
The data types used by the cast must be a type taken from the RADIUS
dictionaries, e.g., ipaddr, integer, etc. These types are not the
same as the data types used in the
configuration files.
|
(cast)lhs OP rhsThe cast text can be any one of the supported data
types, as with the following example:
(ipaddr)&Class == 127.0.0.1In this example, the Class attribute is treated as if it was an IPv4
address and is compared to the address 127.0.0.1
Casting is most useful when the left side of a comparison is a dynamically expanded string. The cast ensures that the comparison is done in a type-safe manner, instead of performing a string comparison.
(integer)`/bin/echo 00` == 0In this example, the string output of the echo program is interpreted as an
integer. It is then compared to the right side via integer
comparisons. Since the integer 00 is equivalent to the integer 0,
the comparison will match. If the comparison had been performed via
string equality checks, then the comparison would fail, because the
strings 00 and 0 are different.