RADIUS Dictionaries Library for .Net Core

Working with RADIUS attributes requires closely following the RFCs as well as vendor-defined rules for encoding the content of AAA packets. Typically, software is written to use the so-called "RADIUS Dictionaries" as generic dictionary data structures. This library provides a different approach, with each attribute being a type that can be easily used with the pattern matching capabilities of C# 8 (switch expressions, for example). Perhaps not for everyone, but perhaps prefered by some.

Usage

This library is distributed as a Nuget package hosted here at github. I may clone it to nuget.org as well at a later date, but for now follow github's instructions to setup a new source.

Now, just add the package to your existing project:

dotnet add package RadiusDictionariesLib

Next, some code. Let's say you are a vendor and want to make sure that your code only makes use of your own VSA's. Well, you can do that:

public void DoTheThing(IArubaAttribute attr) {
    // attr is strongly-typed to be one of the attributes defined in Aruba's dictionary.
    // ...
}

Or, if you want to vary control-flow based on attribute types with C# 8 pattern matching:

string GetTheThing(IRadiusAttribute attr) {
    return attr switch {
        IVendorSpecificAttribute vsa => vsa switch {
            IArubaAttribute => "Aruba calling...",
            {} => "I'm a VSA"
        },
        UserName u => $"It's {u.Value}",
        UserPassword => "Shhh.",
    };
}

To make it easy to do the right thing, where attribute values are defined in a dictionary this library will include them as an attribute-specific enumeration that makes it more difficult to "do the wrong thing" by assigning invalid values to or misinterpreting them. For example:

void BeSafe(Hp.ManagementProtocol attr) {
    // is "HTTP" represented by a 5 or 6? I can never remember...
    if (attr.Value == Hp.ManagementProtocolValue.Http) throw new SecurityException("Nope.");
}

Likewise, where a type is specified for attribute values (e.g. octets, string, integer, etc.) the Value field of the attribute will match:

void TypeSafeValues() {
	var user = new UserName() { Value = "lee" }; // works fine
	var chap = new ChapPassword() { Value = "Password1!" }; // won't compile (requires ArraySegment<byte>)
	var bandwith = new SessionTimeout() { Value = -10 }; // won't compile (value must be unsigned)
	var framedip = new FramedAddress() { Value = IPAddress.Any }; // works fine
}

Building

This project builds like a straight-forward .Net Core project. First, clone the code:

git clone https://github.com/mlhpdx/RadiusDictionariesLib.git radiusdictionarieslib && cd radiusdictionarieslib

Then build, which will automatically run code-generation (T4) on the dictionary files and produce the library:

dotnet build

Run tests, if you'd like:

dotnet test

Versions and Continuous Builds

This library is auto-generated from the FreeRADIUS project's dictionaries (see their repo) text files. Once CI/CD is fully figured-out new commits to the master branch over there will cause this project to automatically build, test and publish a new "preview" package version.

The versioning of preview packages will make use of the FreeRADIUS commit ID as part of the suffix, so the two can be correllated. When a new release of FreeRADIUS is tagged, a "production" version of the RadiusDictionariesLib nuget will be produced with a matching version. If this versioning strategy causes you problems, please file an issue so we can work it out.

Roadmap

I'll add more to this library, perhaps including:

• Cardinality (from the various specifications, not provided in dictionaries)
• Parsing (just attributes, mapping byte buffers to attribute instances)
• Rules checks (content, format, cardinality, etc. for sets of attributes)

This library isn't the right place for things that relate to the RADIUS protocol itself (servers, clients, etc.).

Enjoy!