From ce2317563647e4654da436631ec17981362b9df8 Mon Sep 17 00:00:00 2001
From: Ember 'n0emis' Keske <git@n0emis.eu>
Date: Fri, 11 Mar 2022 22:54:07 +0100
Subject: [PATCH] configure kea

---
 default.nix         | 16 +++++++++++++---
 modules/default.nix | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/default.nix b/default.nix
index 4388e13..9dbc68e 100644
--- a/default.nix
+++ b/default.nix
@@ -47,6 +47,10 @@ in
           };
           addresses = mkOption {
             type = types.listOf types.str;
+            description = ''
+              Addresses to be configured on the bridge interface.
+              WARNING: the primary-ipv4-address to be send as a gateway address via DHCP has to be the first one.
+            '';
           };
           routingTable = mkOption {
             type = types.int;
@@ -73,9 +77,15 @@ in
             default = "";
             type = types.str;
           };
-          searchDomains = mkOption {
-            default = [];
-            type = types.listOf types.str;
+          searchDomain = mkOption {
+            type = types.str;
+          };
+          dhcpExtraConfig = mkOption {
+            description = ''
+              Additional config that will me merged with the kea-subnet4 config
+            '';
+            default = {};
+            type = (pkgs.formats.json {}).type;
           };
           batmanAlgorithm = mkOption {
             default = "batman-iv";
diff --git a/modules/default.nix b/modules/default.nix
index 77ed7db..567fa90 100644
--- a/modules/default.nix
+++ b/modules/default.nix
@@ -116,6 +116,31 @@ let
           RemainAfterExit = true;
         };
       };
+
+      #### KEA / DHCPv4 ####
+      keaInterfaces = if (domCfg.dhcpRange == "") then [] else [ "${mkIfName "bridge"}" ];
+      keaSubnet4 = mkIf (domCfg.dhcpRange != "") ([ ({
+        subnet = domCfg.ipv4Prefix;
+        pools = [
+          {
+            pool = domCfg.dhcpRange;
+          }
+        ];
+        option-data = [
+          {
+            name = "routers";
+            data = head domCfg.addresses;
+          }
+          {
+            name = "domain-name-servers";
+            data = head domCfg.addresses;
+          }
+          {
+            name = "domain-name";
+            data = domCfg.searchDomain;
+          }
+        ];
+      } // domCfg.dhcpExtraConfig) ]);
     };
 
     domConfigs = map (key: getAttr key (mapAttrs mkDomain activeDomains)) (attrNames activeDomains);
@@ -128,7 +153,19 @@ in
     systemd.network.netdevs = mergedConfigs.netdevs;
     systemd.network.networks = mergedConfigs.networks;
     systemd.network.links = mergedConfigs.links;
+
     systemd.services = mergedConfigs.services;
+
     ffnix.fastd.instances = mergedConfigs.fdInstances;
+
+    services.kea.dhcp4 = mkIf (concatLists mergedConfigs.keaInterfaces.contents != []) {
+      enable = true;
+      settings = {
+        interfaces-config = {
+          interfaces = mergedConfigs.keaInterfaces;
+        };
+        subnet4 = mergedConfigs.keaSubnet4;
+      };
+    };
   };
 }