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|
{
config,
lib,
...
}:
let
inherit (lib)
mkEnableOption
mkOption
types
mkIf
attrValues
replaceString
;
cfg = config.foundation.vpn;
inherit (import ../../assets/vpn.nix) users;
interface = "vpn0";
port = 51820;
# while the tunnel uses the lower subnets for the paths,
# the vpn always uses subnet number 10.
subnetIndex = 10;
addressFromTemplate =
template: prefix: "${replaceString "X" (toString subnetIndex) template}/${toString prefix}";
in
{
options.foundation.vpn = {
enable = mkEnableOption "WireGuard VPN server";
externalInterface = mkOption {
type = types.str;
description = "External network interface";
};
};
config = mkIf cfg.enable {
age.secrets.wg-private-key = {
file = ../../secrets/wg-private-key.age;
owner = "systemd-network";
};
networking.firewall.allowedUDPPorts = [ port ];
systemd.network = {
netdevs."30-${interface}" = {
netdevConfig = {
Kind = "wireguard";
Name = interface;
};
wireguardConfig = {
PrivateKeyFile = config.age.secrets.wg-private-key.path;
ListenPort = port;
};
wireguardPeers = map (user: {
PublicKey = user.key;
AllowedIPs = [ (addressFromTemplate user.ip 32) ];
}) (attrValues users);
};
networks."30-${interface}" = {
name = interface;
address = [ (addressFromTemplate "10.123.X.1" 24) ];
linkConfig = {
RequiredForOnline = "no";
};
};
};
networking.nftables.tables.vpn-nat = {
family = "ip";
content = ''
chain postrouting {
type nat hook postrouting priority srcnat; policy accept;
iifname "${interface}" oifname "${cfg.externalInterface}" masquerade
}
chain forward {
type filter hook forward priority 0; policy accept;
iifname "${interface}" oifname "${cfg.externalInterface}" accept
iifname "${cfg.externalInterface}" oifname "${interface}" ct state established,related accept
# drop vpn-sourced traffic headed anywhere but external
iifname "${interface}" drop
}
'';
};
};
}
|
