120 lines
3.4 KiB
Nix
120 lines
3.4 KiB
Nix
{ cfg, lib, pkgs, ... }:
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let
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inherit (pkgs) writeScript writeText;
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inherit (lib) concatMapStringsSep concatStringsSep attrNames unique fold any attrValues catAttrs filter flatten length hasAttr;
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#===== new api v4
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#buildTable :: iptablesAttrSet` -> str
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#todo: differentiate by iptables-version
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buildTables = iptv: ts:
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let
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declareChain = t: cn:
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#TODO: find out what to do whit these count numbers
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":${cn} ${t."${cn}".policy} [0:0]";
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buildChain = tn: cn:
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#"${concatStringsSep " " ((attrNames t."${cn}") ++ [cn])}";
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#TODO: sort by precedence
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#TODO: double check should be unneccessary, refactor!
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if (hasAttr "rules" ts."${tn}"."${cn}") then
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if (ts."${tn}"."${cn}".rules == null) then
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""
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else
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concatMapStringsSep "\n" (rule: "\n-A ${cn} ${rule}") ([]
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++ map buildRule ts."${tn}"."${cn}".rules
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)
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else
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""
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;
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buildRule = rule:
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#TODO implement rule validation-test here
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#
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#target:
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#target needs to be an existing chain (in the same table) or ACCEPT, REJECT, DROP, LOG, QUEUE, RETURN
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#predicate:
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#maybe use iptables-test
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#TODO: howto exit with evaluation error by shellscript?
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#apperantly not possible from nix because evalatution wouldn't be deterministic.
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"${rule.predicate} -j ${rule.target}";
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buildTable = tn:
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"*${tn}\n" +
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concatStringsSep "\n" ([]
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++ map (declareChain ts."${tn}") (attrNames ts."${tn}")
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) +
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#this looks dirty, find a better way to do this (maybe optionalString)
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concatStringsSep "" ([]
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++ map (buildChain tn) (attrNames ts."${tn}")
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) +
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"\nCOMMIT";
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in
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concatStringsSep "\n" ([]
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++ map buildTable (attrNames ts)
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);
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#=====
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rules4 = iptables-version:
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let
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#TODO: find out good defaults.
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tables-defaults = {
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nat.PREROUTING.policy = "ACCEPT";
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nat.INPUT.policy = "ACCEPT";
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nat.OUTPUT.policy = "ACCEPT";
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nat.POSTROUTING.policy = "ACCEPT";
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filter.INPUT.policy = "ACCEPT";
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filter.FORWARD.policy = "ACCEPT";
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filter.OUTPUT.policy = "ACCEPT";
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#if someone specifies any other rules on this chain, the default rules get lost.
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#is this wanted beahiviour or a bug?
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#TODO: implement abstraction of rules
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filter.INPUT.rules = [
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{ predicate = "-m conntrack --ctstate RELATED,ESTABLISHED"; target = "ACCEPT"; }
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];
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};
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tables = tables-defaults // cfg.tables;
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in
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writeText "lass-iptables-rules${toString iptables-version}" ''
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${buildTables iptables-version tables}
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'';
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startScript = writeScript "lass-iptables_start" ''
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#! /bin/sh
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set -euf
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iptables-restore < ${rules4 4}
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ip6tables-restore < ${rules4 6}
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'';
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in
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{
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networking.firewall.enable = false;
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systemd.services.lass-iptables = {
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description = "lass-iptables";
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wantedBy = [ "network-pre.target" ];
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before = [ "network-pre.target" ];
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after = [ "systemd-modules-load.service" ];
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path = with pkgs; [
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iptables
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];
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restartIfChanged = true;
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serviceConfig = {
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Type = "simple";
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RemainAfterExit = true;
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Restart = "always";
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ExecStart = "@${startScript} lass-iptables_start";
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};
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};
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}
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