Merge pull request #263762 from linyinfeng/rttables

nixos/iproute2: use rt_tables.d to avoid IFD

nixos/doc/manual/release-notes/rl-2405.section.md

@@ -35,6 +35,12 @@ The pre-existing [services.ankisyncd](#opt-services.ankisyncd.enable) has been m
 - `services.avahi.nssmdns` got split into `services.avahi.nssmdns4` and `services.avahi.nssmdns6` which enable the mDNS NSS switch for IPv4 and IPv6 respectively.
   Since most mDNS responders only register IPv4 addresses, most users want to keep the IPv6 support disabled to avoid long timeouts.
 
+- `networking.iproute2.enable` now does not set `environment.etc."iproute2/rt_tables".text`.
+
+  Setting `environment.etc."iproute2/{CONFIG_FILE_NAME}".text` will override the whole configuration file instead of appending it to the upstream configuration file.
+
+  `CONFIG_FILE_NAME` includes `bpf_pinning`, `ematch_map`, `group`, `nl_protos`, `rt_dsfield`, `rt_protos`, `rt_realms`, `rt_scopes`, and `rt_tables`.
+
 ## Other Notable Changes {#sec-release-24.05-notable-changes}
 
 <!-- To avoid merge conflicts, consider adding your item at an arbitrary place in the list instead. -->

nixos/modules/config/iproute2.nix

@@ -18,10 +18,9 @@ in
   };
 
   config = mkIf cfg.enable {
-    environment.etc."iproute2/rt_tables" = {
+    environment.etc."iproute2/rt_tables.d/nixos.conf" = {
       mode = "0644";
-      text = (fileContents "${pkgs.iproute2}/lib/iproute2/rt_tables")
-        + (optionalString (cfg.rttablesExtraConfig != "") "\n\n${cfg.rttablesExtraConfig}");
+      text = cfg.rttablesExtraConfig;
     };
   };
 }