Set up tinc VPN

configuration/data/nodes.nix

@@ -0,0 +1,12 @@
{
	"machine-haless-03.cryto.net" = {
		ipv4 = "31.7.187.145";
		internalIpv4 = "10.217.0.5";
		tincPublicKey = builtins.readFile ./tinc-keys/machine-haless-03.cryto.net.pub;
	};
	"machine-borg2-01.cryto.net" = {
		ipv4 = "205.185.121.93";
		internalIpv4 = "10.217.0.6";
		tincPublicKey = builtins.readFile ./tinc-keys/machine-borg2-01.cryto.net.pub;
	};
}

configuration/data/tinc-keys/machine-borg2-01.cryto.net.pub

@@ -0,0 +1 @@
FZNH5Z50Tr/Ep0VpbnIBasUxekLteUphr5Vzi6ONrNH

configuration/data/tinc-keys/machine-haless-03.cryto.net.pub

@@ -0,0 +1 @@
P4MOft3fYOHYpG0I58lYxdZm40u9CXhTH0jvuyIbKZP

configuration/default.nix

@@ -24,6 +24,8 @@ let
		reverseProxy = (import ./presets/nginx/reverse-proxy.nix);
		letsEncrypt = (import ./presets/nginx/lets-encrypt.nix);
	};
	nodes = (import ./data/nodes.nix);
	tincConfiguration = (import ./lib/tinc-configuration.nix);
in {
	network = {
		inherit pkgs;
@@ -33,10 +35,14 @@ in {
	"machine-borg2-01.cryto.net" = { pkgs, lib, ... }: {
		system.stateVersion = "18.09";
		# FIXME: Why is this needed?
		nixpkgs.overlays = [];
		imports = [
			presets.base
			presets.kvm
			./hardware-configurations/machine-borg2-01.nix
			(tincConfiguration { hostname = "machine-borg2-01.cryto.net"; nodes = nodes; })
		];
		boot.loader.grub.device = lib.mkForce "/dev/vda";
@@ -77,6 +83,7 @@ in {
			presets.base
			presets.kvm
			./hardware-configurations/machine-haless-03.nix
			(tincConfiguration { hostname = "machine-haless-03.cryto.net"; nodes = nodes; })
		];
		deployment.healthChecks.http = let

configuration/lib/tinc-configuration.nix

@@ -0,0 +1,62 @@
/* TODO: Translate this to a service/module at some point? Something like 'cryto.network' that handles all the internal-networking stuff. */
{ hostname, nodes, pingInterval ? 10 }:
	{ lib, ... }: let
		/* NOTE: We cannot just use simple string interpolation, because tinc's configuration format is not indentation-tolerant. Therefore, we do some programmatic concatenation magic to ensure that everything is indentation-free, without turning this file into a mess of wrong indentation. */
		generateConfiguration = options:
			let
				keys = builtins.attrNames options;
				toPairs = map (key: {key = key; value = options.${key};});
				createConfigEntries = map (item: "${item.key} = ${toString item.value}");
			in
				builtins.concatStringsSep "\n" (createConfigEntries (toPairs keys));
	in {
		deployment.secrets = {
			"tinc-key" = {
				source = "../private/${hostname}/tinc-key.priv";
				destination = "/etc/tinc/cryto/ed25519_key.priv";
				owner = { user = "tinc.cryto"; };
				action = [ "systemctl" "restart" "tinc.cryto.service" ]; 
			};
		};
		services.tinc.networks.cryto = {
			debugLevel = 3;
			extraConfig = generateConfiguration {
				AutoConnect = "yes";
				PingInterval = pingInterval;
			};
			hosts = let
				mapper = nodeName: nodeConfiguration:
					lib.nameValuePair
						/* NOTE: The below is because for a machine named `foo.bar-baz.net`, tinc expects a configuration file named `foo_bar_baz_net`. */
						( builtins.replaceStrings [ "." "-" ] [ "_" "_" ] nodeName )
						( generateConfiguration {
							# Address = nodeName;
							/* TODO: Figure out why a DNS name doesn't work here ("Error looking up machine-borg2-01.cryto.net port 655: Device or resource busy") */
							Address = nodeConfiguration.ipv4;
							Subnet = "${nodeConfiguration.internalIpv4}/32";
							Ed25519PublicKey = nodeConfiguration.tincPublicKey;
						} );
			in lib.mapAttrs' mapper nodes;
		};
		networking.interfaces."tinc.cryto".ipv4.addresses = [{
			address = nodes.${hostname}.internalIpv4;
			prefixLength = 24;
		}];
		networking.firewall = {
			allowedTCPPorts = [
				655
			];
			allowedUDPPorts = [
				655
			];
			trustedInterfaces = [
				"tinc.cryto"
			];
		};
	}

deploy-secrets

@@ -0,0 +1 @@
SSH_USER=root morph --keep-result upload-secrets "$@" configuration/default.nix

notes/tinc-key-setup.txt

@@ -0,0 +1,5 @@
# From the machine's `private` folder:
nix-shell --command 'tinc --batch --config ./ -n cryto generate-ed25519-keys' --packages tinc_pre
# NOTE: Change the machine name!
mv ed25519_key.priv tinc-key.priv && sed -i -r 's/^Ed25519PublicKey = //' ed25519_key.pub && mv ed25519_key.pub ../../configuration/data/tinc-keys/machine-haless-03.cryto.net.pub