prefer modules/dhcp4c over system.services.network.dhcp.client

modules/dhcp4c/client.nix

@@ -0,0 +1,47 @@
+{
+  liminix,
+  writeAshScript,
+  serviceFns,
+  lib,
+}:
+{ interface }:
+let
+  inherit (liminix.services) longrun;
+  name = "${interface.name}.dhcpc";
+  script = writeAshScript "dhcp-notify" { } ''
+    . ${serviceFns}
+    exec 2>&1
+    action=$1
+
+    set_address() {
+        ip address replace $ip/$mask dev $interface
+        (in_outputs ${name}
+         for i in lease mask ip router siaddr dns serverid subnet opt53 interface ; do
+            (printenv $i || true) > $i
+         done
+         touch state)
+    }
+    case $action in
+      deconfig)
+        ip address flush $interface
+        ip link set up dev $interface
+        ;;
+      bound)
+        # this doesn't actually replace, it adds a new address.
+        set_address
+        # echo  >/proc/self/fd/10
+        ;;
+      renew)
+        set_address
+        ;;
+      nak)
+        echo "received NAK on $interface"
+        ;;
+    esac
+  '';
+in
+longrun {
+  inherit name;
+  run = "exec /bin/udhcpc -n -A 15 -f -i $(output ${interface} ifname) -x hostname:$(cat /proc/sys/kernel/hostname) -s ${script}";
+  dependencies = [ interface ];
+}

modules/dhcp4c/default.nix

@@ -0,0 +1,38 @@
+## DHCP6 client module
+## ===================
+##
+##  This is for use if you have an IPv6-capable upstream that provides
+##  address information and/or prefix delegation using DHCP6. It
+##  provides a service to request address information in the form of a
+##  DHCP lease, and two dependent services that listen for updates
+##  to the DHCP address information and can be used to update
+##  addresses of network interfaces that you want to assign those
+##  prefixes to
+
+{
+  lib,
+  pkgs,
+  config,
+  ...
+}:
+let
+  inherit (lib) mkOption types;
+  inherit (pkgs) liminix;
+in
+{
+  options = {
+    system.service.dhcp4c = {
+      client = mkOption { type = liminix.lib.types.serviceDefn; };
+    };
+  };
+  config.system.service.dhcp4c = {
+    client = config.system.callService ./client.nix {
+      interface = mkOption {
+        type = liminix.lib.types.interface;
+        description = "interface to query for DHCP";
+      };
+    };
+  };
+  # this is already configured in modules/busybox.nix
+  config.programs.busybox.applets = [ "udhcpc" ];
+}

modules/network/default.nix

@@ -146,11 +146,16 @@ in
         };
       };
 
-      dhcp.client = config.system.callService ./dhcpc.nix {
-        interface = mkOption {
-          type = liminix.lib.types.service;
+      dhcp.client =
+        lib.warn ''
+          system.services.network.dhcp.client is deprecated and will
+          be removed in 2026.  Use system.service.dhcp4c instead
+        ''
+        config.system.callService ./dhcpc.nix {
+          interface = mkOption {
+            type = liminix.lib.types.service;
+          };
         };
-      };
 
     };
   };