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vcp-bula-nixfiles/modules/uplink-selector/default.nix
2022-07-15 01:16:51 +02:00

115 lines
2.6 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.clerie.uplink-selector;
startScript = pkgs.writeScriptBin "uplink-selector-start" ''
#! ${pkgs.runtimeShell} -e
ip46() {
ip "$@"
ip -6 "$@"
}
ip46 rule flush || true
# Route everything except default route first
ip46 rule add lookup main suppress_prefixlength 0 prio 10000
# Decide which uplink to use
${concatStrings (mapAttrsToList (iface: ifacecfg: ''
ip46 rule add iif ${iface} lookup ${cfg.uplinks.${ifacecfg.uplink}.table} prio 20000
'') cfg.interfaces)}
# Fallback to the main default table
ip46 rule add lookup main prio 32000
'';
stopScript = pkgs.writeScriptBin "uplink-selector-stop" ''
#! ${pkgs.runtimeShell} -e
ip rule flush || true
ip -6 rule flush || true
'';
in
{
options = {
clerie.uplink-selector = {
enable = mkOption {
type = types.bool;
default = false;
description =
''
Select a default gateway for each interface manually
'';
};
uplinks = mkOption {
default = { };
type = with types; attrsOf (submodule {
options = {
table = mkOption {
type = types.str;
example = "5001";
description = "Route table containing the gateway route of this uplink";
};
};
});
description =
''
Uplink interface name
'';
};
interfaces = mkOption {
default = { };
type = with types; attrsOf (submodule {
options = {
uplink = mkOption {
type = types.nullOr types.str;
example = "uplink-a";
description = "Name of the uplink that should used as a default gateway by this interface";
};
};
});
description =
''
Interface
'';
};
};
};
config = mkIf cfg.enable {
environment.systemPackages = [ pkgs.iproute2 ];
systemd.services.uplink-selector = {
description = "Uplink Selector";
before = [ "network.target" ];
wantedBy = [ "network.target" ];
after = [ "network-pre.target" ];
path = [ pkgs.iproute2 ];
unitConfig.ConditionCapability = "CAP_NET_ADMIN";
serviceConfig = {
Type = "oneshot";
RemainAfterExit = true;
ExecStart = "@${startScript}/bin/uplink-selector-start uplink-selector-start";
ExecStop = "@${stopScript}/bin/uplink-selector-stop uplink-selector-stop";
};
};
};
}