RADIUS

The system provides two Python objects alc.radius, instance of class alc.Radius, and alc.radius.attributes, instance if class alc.RadiusAttributes, to inspect and modify RADIUS packets.

Note

Only the pre-provided alc.radius/alc.radius.attributes object should be used in script, the class alc.Radius/alc.RadiusAttributes should not be used directly.

The `alc.Radius` class

Provides packet level operations.

header()

Returns a dictionary containing the value of the RADIUS header fields:

code (integer)

id (integer)

len (integer)

authenticator (bytes)

print(alc.radius.header())
# {'code': 1, 'id': 202, 'len': 133, 'authenticator': b'\xe5C\xabM\xa1\x82(\x95\xe2\x84\xfai\xe6|\xd8\x92'}

drop(): Drops the packet.

The `alc.RadiusAttributes` class

Provides attribute level operations.

isSet(type, /)

Checks if a specified attribute is present.

Parameters: type (int|tuple) – Attribute type. If the parameter is a tuple, it should be interpreted as an attribute identifier. See Attribute identifiers.
Return type: bool

get(type, /)

Retrieves the value of a specified attribute.

Parameters: type (int|tuple) – Attribute type. If the parameter is a tuple, it should be interpreted as an attribute identifier. See Attribute identifiers.
Returns: Value of the attribute, or None if not present.
Return type: bytes

getTuple(type, /)

Retrieves all values of a specified attribute.

Parameters: type (int|tuple) – Attribute type. If the parameter is a tuple, it should be interpreted as an attribute identifier. See Attribute identifiers.
Returns: All values collected in a tuple.
Return type: tuple

set(type, value, /)

Adds an attribute with the specified type and value. This overwrites previously existing values if present.

Parameters

type (int|tuple) – Attribute type. If the parameter is a tuple, it should be interpreted as an attribute identifier. See Attribute identifiers.
value (bytes|tuple) – Attribute value. If it is a tuple, multiple attributes with the same type are added, one for each item in the tuple.

clear(type, /)

Removes all attributes with the specified type.

Parameters: type (int|tuple) – Attribute type. If the parameter is a tuple, it should be interpreted as an attribute identifier. See Attribute identifiers.

Note

The following RADIUS attributes or VSAs are read-only:

Message-Authenticator (80)
Alc-LI-Action (26.6527.122)
Alc-LI-Destination (26.6527.123)
Alc-LI-FC (26.6527.124)
Alc-LI-Direction (26.6527.125)
Alc-LI-Intercept-Id (26.6527.138)
Alc-LI-Session-Id (26.6527.139)

Warning

All methods in alc.RadiusAttributes raise appropriate TypeError or ValueError messages in cases of invalid arguments.

Attribute iteration

The class alc.RadiusAttributes acts as an iterator over the attributes, yielding a tuple (identifier, value) for each attribute present.

import alc

print(list(alc.radius.attributes))
# [((8,), b'\xc0\xa8\x01\x14'), ((26, 6527, 9), b'\x08\x08\x08\x08'), ((26, 6527, 10), b'\x08\x08\x04\x04')]
for attr, value in alc.radius.attributes:
   dotted_number = ".".join(map(str, attr))
   print("{} = {}".format(dotted_number, value))
#8 = b'\xc0\xa8\x01\x14'
#26.6527.9 = b'\x08\x08\x08\x08'
#26.6527.10 = b\x08\x08\x04\x04'

Attribute access

Besides the methods defined for the alc.Radius class, the attributes can also be fetched, set, and cleared using the container syntax of Python. The keys by which the attributes can be reached are the identifier tuples as described in Attribute identifiers. The values are tuples of bytes.

print(alc.radius.attributes[(8,)])
#(b'\xc0\xa8\x01\x14',)
print(alc.radius.attributes[(241, 26, 6527, 4)])
#()

Checking if an attribute is present can be done via the in operator.

print((8,) in alc.radius.attributes)
#True
print((241, 26, 6527, 4) in alc.radius.attributes)
#False

Adding or overwriting an attribute can be done by assigning a value to the indexed attributes object. When setting multiple values for an attribute, the value should be a tuple of bytes. When setting a single value for an attribute, the value can be a 1-tuple of bytes or the individual bytes.

alc.radius.attributes[(8,)] = b'\xc0\xa8\x01\x14'
alc.radius.attributes[(8,)] = (b'\xc0\xa8\x01\x14',)
alc.radius.attributes[(25,)] = (b'red', b'green', b'blue')

Clearing an attribute can be performed with the del operator.

del alc.radius.attributes[(8,)]

Attribute identifiers

Attribute identifiers as described in RFC 6929#section-2.7 can be used to target a specific attribute. They are specified in Python as a tuple of integers, where each item in the tuple corresponds to a number in the “dotted number” format.

Type	Name	Identifier	Python object
Normal	NAS-IP-Address	4	(4, )
Extended	Frag-Status	241.1	(241, 1)
Vendor-Specific	Alc-Subsc-Prof-Str	26.6527.12	(26, 6527, 12)
Extended-Vendor-Specific	Alc-PPPoE-Client-Service	241.26.6527.1	(241, 26, 6527, 1)

RADIUS

The alc.Radius class

The alc.RadiusAttributes class

Attribute iteration

Attribute access

Attribute identifiers

The `alc.Radius` class

The `alc.RadiusAttributes` class