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WireNix is a Nix Flake designed to make creation of Wireguard mesh networks easier. The simplist and most likely layout is a full mesh network, but Wirenix can also support arbitrary graph topologies.

Reading the README

Due to Nix's dynamic typing, I have opted to define configurations in psuedo-typescript to make options more legible. I have chosen typescript because it looks somewhat like JSON and is easy to understand. Examples will still be given in Nix EL.

You can start by reading the "ACL Configuration" section, then reading the "Quick Start" section for how to configure your machines. Other sections exist to provide helpful context and advanced usage, but should not be necessary for a working setup.

Wirenix assumes a flakes setup, that's what I use. Maybe it works without flakes, maybe not. I'm not familiar enough with the non-flakes landscape to provide support. I am open to making simple changes to make using this project work without flakes if anyone has suggestions or wants to submit a patch.

ACL Configuration

The ACL is a nix attrset designed to be represented in JSON for easy importing and potential use outside of the nix ecosystem. The vast majority of all your wirenix configuration will end up in here, with a few exceptions noted later.

top level acl

type ACL = {
  version?: str;
  subnets: subnet[];
  groups: group[];
  peers: peer[];
  connections: connection[];
  extraArgs?: attrset; // goes to intermediate config
};

Version is used to check to find the right parser and is required. Using an older. At the moment there is only "v1" builtin.

extraArgs is explained later, and can be ignored unless you are trying to make your own integrations.

subnet

type subnet = {
  name: str;
  endpoints?: endpoint[];
  presharedKeyFile?: str;
  extraArgs?: attrset; // goes to intermediate config subnet
};

! WARNING ! If your subnet name has a ".", the wireguard connection's name will be everything preceding the ".". This is because there is a hard limit of 15 characters for wireguard connection names. For example, if your subnet is named "myVPN.mydomain.com" (18 characters), the wireguard connection will be named "myVPN". This is useful because the longer name will still be used to generate a unique ip and in the hosts file, just not for the netdev name. This unfortunately means that you cannot share subdomains across different domain on the same machine. A workaround is to use dashes if your FQDN is under 15 characters.

Group

type group = {
  name: str;
  endpoints?: endpoint[];
  extraArgs?: attrset; // goes to intermediate config group
};

Peer:

type peer = {
  name: str;
  subnets: [subnetName: str]: {
    listenPort: int;
    ipAddresses?: str[];
    extraArgs?: attrset; // goes to intermediate config subnetConnection
  };
  publicKey: str;
  privateKeyFile: str; 
  groups?: str[];
  endpoints?: endpoint[];
  extraArgs?: attrset; // goes to intermediate config peer
};

"[subnetName: str]: {...}" means "subnets" is an attrset with string typed keys, and values that follow the typing of the nested object "...".

Connection

type connection = {
  a: filter;
  b: filter;
  subnets: str[];
  extraArgs?: attrset; // merged into intermediate config peerConnection
};

Connections connect all peers matching filter a to all peers matching filter b, and all peers matching filter b to all peers matching filter a subnets filters the connection to only be made over the subnets listed. It is recomended to use the subnets property iff the subnet filter is also used (the subnet filter on its own will connect all shared subnets of machines in a and b, even subnets not mentioned in the filters if they are shared).

Endpoint:

type endpoint = {
  match?: filter;
  ip?: str;
  port?: int;
  persistentKeepalive?: int;
  dynamicEndpointRefreshSeconds?: int;
  dynamicEndpointRefreshRestartSeconds?: int;
  extraArgs?: attrset; // merged to intermediate config peerConnection.endpoin
};

Endpoints are merged in this order: First lists of endpoints are merged top to bottom, with the bottom endpoints overriding the top ones. Then, lists are merged in this order: subnet -> group -> peer; with peer being the highest priority, overriding others. A good layout is to set ports in subnet, ip in peer, and leave group empty. group endpoints can be useful for specifying connection details across port forwarded NATs, however.
Note that dynamicEndpointRefreshSeconds and dynamicEndpointRefreshRestartSeconds are ignored for connecting networkd peers.

Filter

type filter = {
  type: ["peer" | "group" | "subnet"];
  rule: [ "is" | "not" ];
  value: str;
}[]; // <==== Important! It's a list

A filter is a list of filter rules. Each filter rule has the attributes type, rule and value. type selects what to match with, rule selects whether to invert the match ("not") or not ("is"). Value is the value to search for. Multiple filter rules in the filter list combine as the intersection. For example:

[
  {type="group"; rule="is"; value="desktops"}
  {type="peer"; rule="not"; value="joesdesktop"}
]

This will select all peers in the desktop group, except the peer named joesdesktop.

extraArgs

extraArgs is intentionally left alone. I promise I won't ever set extraArgs, but any value in it will be forwarded on to the corresponding section in the intermediate configuration. Because of this, it can be used to pass data into user defined Configuration Modules. Most users can ignore extraArgs.

Quick Start

1. Make your ACL according to the "ACL Configuration" section. You can look in the examples/acl folder for examples.

2. Include the module in your flake config:

   ...
   inputs.wirenix.url = "sourcehut:~msalerno/wirenix";
   outputs = { self, nixpkgs, wirenix }: {
   nixosConfigurations = {
       example = nixpkgs.lib.nixosSystem rec {
       system = "x86_64-linux";
       modules = [
           ./machines/example.nix
           wirenix.nixosModules.default
       ] 
       };
   };
   

3. Configure wirenix in your nixosConfiguration (./machines/example.nix in this case):

   wirenix = {
       enable = true;
       peerName = "example" # defaults to hostname otherwise
       configurer = "static" # defaults to "static", could also be "networkd"
       keyProviders = ["acl"]; # could also be ["agenix-rekey"] or ["acl" "agenix-rekey"]
       # secretsDir = ../../secrets; # only if you're using agenix-rekey
       aclConfig = import ../../acl.nix;
   };
   

4. Profit

Architecture

WireNix consists of 5 main components:

1. The shared ACL Configuration
2. Parser Modules
3. The intermediate Configuration
4. Configuration Modules
5. The Key Providers

The goal of splitting WireNix into modules is both for my own sanity when developing, and to make it hackable without requiring users to make their own fork. Users are able to specify their own Parser Modules, enabling them to use their own preferred ACL syntax if they desire. Users can also specify their own configuration modules, allowing them to add compatibility to for other network stacks or to enable their own modules. It is also possible to add new key providers. Using both custom Parser and Configuration modules enables essentially rewriting this flake however you see fit, all without making a fork (although at that point I may question why you don't write your own module from scratch).

ACL

The shared ACL configuration describes the full network topology. It does not need to consist only of NixOS peers The details of this file are documented in the "Top Level ACL" section. You can make your own ACL configuration format so long as you keep the "version" field and set it to some unique name.

Parser Modules

Parser Modules are responsible for taking an ACL and converting it to the intermediate configuration format. Parser modules are selected by matching the ACL version field. A parser module must take an ACL and return the corresponding Intermediate Configuration. A parser has the following interface:

type parser = (inputs: attrset, aclConfig: ACL) => intermediateConfiguration;

You can register your own parser module like so:

wirenix.additionalParsers = {
    myParser = import ./my-parser.nix;
}

And then, in your ACL, set the version:

...
version = "myParser";
...

Intermediate Configuration

The Intermediate Configuration is a recursive attrset that is more suited for being used in a NixOS configuration than the ACL Configuration. Unlike the ACL, the intermediate configuration is more verbose, easier to traverse, contains duplicate information, and is recursive. This allows cross version compatibility so long as the intermediate configuration doesn't change. Any changes will likely only be the addition of optional features that do not interfere with existing intermediate configuration use, though at this stage there are no guarentees.
Take note while reading that certain structures may be similar to the ACL, but they are not necessarily the same as their ACL counterparts.

Root Structure

type intermediateConfiguration = {
    peers: {[peerName: str]: peer};
    subnets: {[subnetName: str]: subnet};
    groups: {[groupName: str]: group};
    extraArgs?: attrset;
}

Peer

type peer = {
    subnetConnections: {[subnetName: str]: subnetConnection};
    publicKey: str;
    privateKeyFile: str; 
    groups?: {[groupName: str]: group}    
    extraArgs?: attrset;
};

Subnet

type subnet = {
    peers: {[peerName: str]: peer};
    presharedKeyFile?: str;
    extraArgs?: attrset;
};

Group

type group = {
    peers: {[peerName: str]: peer};
    extraArgs?: attrset;
};

Subnet Connection

type subnetConnection = {
    subnet: subnet;
    ipAddresses: str[];
    listenPort: int;
    peerConnections: {[peerName: str]: peerConnection};
    extraArgs?: attrset;
};

Peer Connection

type peerConnection = {
    peer: peer;
    ipAddresses: str[];
    endpoint: endpoint;
    extraArgs?: attrset;
};

Endpoint

type endpoint = {
   ip: str;
   port: int;
   persistentKeepalive?: int;
   dynamicEndpointRefreshSeconds?: int;
   dynamicEndpointRefreshRestartSeconds?: int;
   extraArgs?: attrset;
};

Configuration Modules

Configuration Modules take the Key provider list and Intermediate Configuration to produce NixOS configurations. By default, there exist configuration modules for setting up wireguard with the static network configuration (default) or networkd configuration. A configurer has the following interface:

type configurer = (inputs: attrset, keyProviders: keyProvider[], intermediateConfig: intermediateConfiguration) => nixosConfiguration;

You can set which module is used (or use your own module) in your flake.nix file:

wirenix.configurer = "networkd"; 

or for your own module:

wirenix.additionalConfigurers.myConfigurer = import ./my-configurer.nix;
wirenix.configurer = "myConfigurer";

Key Providers

Configurers require a list of key providers to query for information about wireguard key pairs. The providers in the list are queried in order, moving on to the next provider if null is returned. This allows keeping key pairs in multiple places, but most likely the key provider list will be a singleton. Key Providers have the following stracture:

type keyProvider = {
    config: nixosConfig;
    getPeerPubKey: (otherPeerName: str) => str;
    getPrivKeyFile: str;
    getSubnetPSKFile: (subnetName: str) => str;
};

You can add your own key providers like so:

wirenix.additionalKeyProviders.myKeyProvider = import ./my-key-provider.nix;
wirenix.keyProviders = ["myKeyProvider"];

Integrations:

By default, WireNix supports setting wireguard keypairs with agenix-rekey. WireNix also supports using either networkd or the nixos static network configuration (default).

Using networkd:

systemd.network.enable = true;
wirenix = {
  enable = true;
  configurer = "networkd"
  aclConfig = import ./my-acl.nix;
};

Using static configuration:

wirenix = {
  enable = true;
  configurer = "static"
  aclConfig = import ./my-acl.nix;
};

Using agenix-rekey (assuming it's already set up properly)

wirenix = {
  enable = true;
  keyProviders = ["agenix-rekey"];
  secretsDir = ../../secrets;
  aclConfig = import ./my-acl.nix;
};

Using the ACL's keypairs if specified, otherwise using agenix-rekey (reverse order not possible)

wirenix = {
  enable = true;
  keyProviders = ["acl" "agenix-rekey"];
  secretsDir = ../../secrets;
  aclConfig = import ./my-acl.nix;
};

Troubleshooting

Wirenix tries to stay seperated from the inner working of your config for as long as possible. As a result, you can do most of your troubleshooting in the nix repl:

$ nix repl
$ nix-repl> :l <nixpkgs>
> Added 17766 variables.

$ nix-repl> :lf "sourcehut:~msalerno/wirenix"
> Added 11 variables.
# named the wirenix lib 'wnlib' to prevent issues with nixpkgs.lib in the repl
$ nix-repl> parse = wnlib.defaultParsers.v1 {inherit lib;}

$ nix-repl> keyProviders = [wnlib.defaultKeyProviders.acl]

$ nix-repl> configure = wnlib.defaultConfigurers.static {inherit lib;} keyProviders

$ nix-repl> acl = import ./examples/fullMesh/acl.nix # replace with your acl

# get intermediate config
$ nix-repl> intConfig = parse acl
# you can explore the structure
$ nix-repl> intConfig
> { groups = { ... }; peers = { ... }; subnets = { ... }; }
# we can also see what the generated network config would be
$ nix-repl> genPeerConfig = configure intConfig
# `configure` is only partially applied, and genPeerConfig still needs a peer name
$ nix-repl> genPeerConfig
> «lambda @ /nix/store/h8gyjv62yddarvr533vi8f2rh5w0wh1p-source/configurers/static.nix:1:33»

# we can then inspect the result
$ nix-repl> :p genPeerConfig "peer1"
> { networking = { wireguard = { interfaces = { ... }; }; }

# printing the intermediate config with :p will cause a stack overflow
# but we have a helper function for this
$ nix-repl> :p wnlib.breakIntermediateRecursion intConfig
> { a bunch of hard to read data }
# you can get a string and paste it into echo -e for pretty printing
$ nix-repl> lib.generators.toPretty {} (wnlib.breakIntermediateRecursion intConfig)
> "even uglier result but it copy pastes well"

In your terminal:

$ echo -e "paste the big text result from nix repl in here"
> a nice result

Current Issues / Drawbacks

• WireNix does not do NAT traversal, routing, DNS (although it will add to the hosts file), or anything like that. It's up to you to forward the correct ports, set the right firewall rules, make routing rules, do NAT traversal, etc.
• WireNix does not allow for dynamic addition of peers. If you need something more dynamic, look into Tailscale/Headscale.
• Peers cannot have multiple keys. If this is a desirable feature I may think of adding it, but I cannot think of a good reason for it.
• There's no testing infrastructure in place right now, and plenty of untested scenarios.
• Currently this will create empty sops and age top level attributes in your config if you don't already have them. It has to do with some terrible hackery I did in wire.nix to prevent infinite recursion. If any Nix wizards out there want to send in a patch it would be mutch appreciated!

Other Bits

• The netdev, network, and interfaces options for a subnet on a client will have the same key as your subnet name, except in the case where the name contains a '.', in which case it will be truncated to the first stretch of text before the '.'. Networkd files have a priority of 50.
• It's not unexpected to add your own configuration to these options. If something breaks, reach out.
• Sourcehut is weird, if you don't know, you can submit issues on my wirenix tracker and read the git email guide for info on submitting patches. You can also email issues to ~msalerno/wirenix@todo.sr.ht And they'll end up on the same issue tracker.

License

This project is licensed under the MPL 2.0

Glosary

ACL

Access Control List: This is your shared configuration for the network.

Subnet

In Wirenix, the word subnet represents any network of connected peers. In the implementation, subnets are keyed by their name property. Subnet names define the initial 32 bits after fd in of an the IPv6 addresses peers connecting to the subnet will use. Generally speaking, one subnet = one wireguard interface for each client on the subnet.

Peer

In Wirenix, peer is any machine with a unique public key In the implementation, peer names define last 80 bits of their IPv6 address.

Group

In Wirenix, a group is just a tag that peers can have. These are used for matching peers and can contain arbitrary names.

Endpoint

In wirenix, an endpoint specifies external IP of a peer that other peers should connect to.
In the ACL configuration, endpoints can exist on subnets, groups, and peers, but these are just for convenience. Think of adding an endpoint to a subnet or group as being the same as adding the endpoint to all peers in the subnet or group.
Endpoints have filters, which can specify for which connecting clients the endpoint will apply to.

Filter

In Wirenix, a filter is used to select peers by their subnets, groups, and names. A filter is made up of filter rules, specifying multiple rules will yield the intersection of those rules.
Note that selecting by peer name will always return a list of 1 or 0 entries, on account of names needing to be unique.