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-rw-r--r--3modules/lass/iptables.nix166
1 files changed, 166 insertions, 0 deletions
diff --git a/3modules/lass/iptables.nix b/3modules/lass/iptables.nix
new file mode 100644
index 000000000..6d567ca23
--- /dev/null
+++ b/3modules/lass/iptables.nix
@@ -0,0 +1,166 @@
+arg@{ config, lib, pkgs, ... }:
+
+let
+ inherit (pkgs) writeScript writeText;
+ inherit (lib) concatMapStringsSep concatStringsSep attrNames unique fold any attrValues catAttrs filter flatten length hasAttr mkEnableOption mkOption mkIf types;
+
+ cfg = config.lass.iptables;
+
+ out = {
+ options.lass.iptables = api;
+ config = mkIf cfg.enable imp;
+ };
+
+ api = {
+ enable = mkEnableOption "iptables";
+
+ #tables.filter.INPUT = {
+ # policy = "DROP";
+ # rules = [
+ # { predicate = "-i retiolum"; target = "ACCEPT"; priority = -10; }
+ # ];
+ #};
+ #new api
+ tables = mkOption {
+ type = with types; attrsOf (attrsOf (submodule ({
+ options = {
+ policy = mkOption {
+ type = str;
+ default = "-";
+ };
+ rules = mkOption {
+ type = nullOr (listOf (submodule ({
+ options = {
+ predicate = mkOption {
+ type = str;
+ };
+ target = mkOption {
+ type = str;
+ };
+ precedence = mkOption {
+ type = int;
+ default = 0;
+ };
+ };
+ })));
+ default = null;
+ };
+ };
+ })));
+ };
+ };
+
+ imp = {
+ networking.firewall.enable = false;
+
+ systemd.services.lass-iptables = {
+ description = "lass-iptables";
+ wantedBy = [ "network-pre.target" ];
+ before = [ "network-pre.target" ];
+ after = [ "systemd-modules-load.service" ];
+
+ path = with pkgs; [
+ iptables
+ ];
+
+ restartIfChanged = true;
+
+ serviceConfig = {
+ Type = "simple";
+ RemainAfterExit = true;
+ Restart = "always";
+ ExecStart = "@${startScript} lass-iptables_start";
+ };
+ };
+ };
+
+ #buildTable :: iptablesAttrSet` -> str
+ #todo: differentiate by iptables-version
+ buildTables = iptv: ts:
+ let
+ declareChain = t: cn:
+ #TODO: find out what to do whit these count numbers
+ ":${cn} ${t."${cn}".policy} [0:0]";
+
+ buildChain = tn: cn:
+ #"${concatStringsSep " " ((attrNames t."${cn}") ++ [cn])}";
+
+ #TODO: sort by precedence
+ #TODO: double check should be unneccessary, refactor!
+ if (hasAttr "rules" ts."${tn}"."${cn}") then
+ if (ts."${tn}"."${cn}".rules == null) then
+ ""
+ else
+ concatMapStringsSep "\n" (rule: "\n-A ${cn} ${rule}") ([]
+ ++ map buildRule ts."${tn}"."${cn}".rules
+ )
+ else
+ ""
+ ;
+
+
+ buildRule = rule:
+ #TODO implement rule validation-test here
+ #
+ #target:
+ #target needs to be an existing chain (in the same table) or ACCEPT, REJECT, DROP, LOG, QUEUE, RETURN
+
+ #predicate:
+ #maybe use iptables-test
+ #TODO: howto exit with evaluation error by shellscript?
+ #apperantly not possible from nix because evalatution wouldn't be deterministic.
+ "${rule.predicate} -j ${rule.target}";
+
+ buildTable = tn:
+ "*${tn}\n" +
+ concatStringsSep "\n" ([]
+ ++ map (declareChain ts."${tn}") (attrNames ts."${tn}")
+ ) +
+ #this looks dirty, find a better way to do this (maybe optionalString)
+ concatStringsSep "" ([]
+ ++ map (buildChain tn) (attrNames ts."${tn}")
+ ) +
+ "\nCOMMIT";
+ in
+ concatStringsSep "\n" ([]
+ ++ map buildTable (attrNames ts)
+ );
+
+#=====
+
+ rules4 = iptables-version:
+ let
+ #TODO: find out good defaults.
+ tables-defaults = {
+ nat.PREROUTING.policy = "ACCEPT";
+ nat.INPUT.policy = "ACCEPT";
+ nat.OUTPUT.policy = "ACCEPT";
+ nat.POSTROUTING.policy = "ACCEPT";
+ filter.INPUT.policy = "ACCEPT";
+ filter.FORWARD.policy = "ACCEPT";
+ filter.OUTPUT.policy = "ACCEPT";
+
+ #if someone specifies any other rules on this chain, the default rules get lost.
+ #is this wanted beahiviour or a bug?
+ #TODO: implement abstraction of rules
+ filter.INPUT.rules = [
+ { predicate = "-m conntrack --ctstate RELATED,ESTABLISHED"; target = "ACCEPT"; }
+ ];
+ };
+ tables = tables-defaults // cfg.tables;
+
+ in
+ writeText "lass-iptables-rules${toString iptables-version}" ''
+ ${buildTables iptables-version tables}
+ '';
+
+ startScript = writeScript "lass-iptables_start" ''
+ #! /bin/sh
+ set -euf
+ iptables-restore < ${rules4 4}
+ ip6tables-restore < ${rules4 6}
+ '';
+
+in
+out
+