From f354cefff68bd8b3d66e077bd35a857f155d70dd Mon Sep 17 00:00:00 2001
From: Tim Keller <tjk@tjkeller.xyz>
Date: Tue, 19 Aug 2025 21:38:50 -0500
Subject: add net interface labeling feature

---
 modules/root/net-iface-labels.nix | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 modules/root/net-iface-labels.nix

(limited to 'modules/root/net-iface-labels.nix')

diff --git a/modules/root/net-iface-labels.nix b/modules/root/net-iface-labels.nix
new file mode 100644
index 0000000..4949659
--- /dev/null
+++ b/modules/root/net-iface-labels.nix
@@ -0,0 +1,27 @@
+{ config, lib, ... }: let
+	validMac = str: builtins.match ''^[0-9a-fA-F]{2}(:[0-9a-fA-F]{2}){5}$'' str != null;
+	macAddressType = lib.types.str // {
+		check = validMac;
+		description = "a mac address (xx:xx:xx:xx:xx:xx)";
+	};
+in {
+	options.networking.interfaceLabels = {
+		enable = lib.mkEnableOption "manually label network interfaces";
+		interfaces = lib.mkOption {
+			type = lib.types.attrsOf macAddressType;
+			default = {};
+			example = {
+				"lan0" = "00:11:22:33:44:55";
+				"lan1" = "66:77:88:99:AA:BB";
+			};
+			description = "label network interfaces by their mac address";
+		};
+	};
+
+	config = lib.mkIf config.networking.interfaceLabels.enable {
+		networking.usePredictableInterfaceNames = false;
+		services.udev.extraRules = lib.concatStringsSep "\n" (
+			lib.mapAttrsToList (name: mac: ''ACTION=="add", SUBSYSTEM=="net", ATTR{address}=="${mac}", NAME="${name}"'') config.networking.interfaceLabels.interfaces
+		);
+	};
+}
-- 
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