Files
nixos/hosts/nas/modules/cyberghost.nix

122 lines
3.8 KiB
Nix

{ config, pkgs, ... }:
let
localNetwork = "10.42.96.0/20";
vpnServer = "87-1-hu.cg-dialup.net";
in
{
# SOPS secrets for CyberGhost credentials
sops.secrets.cyberghost-auth = {
mode = "0400";
owner = "root";
};
sops.secrets.cyberghost-ca = {
mode = "0400";
owner = "root";
};
sops.secrets.cyberghost-cert = {
mode = "0400";
owner = "root";
};
sops.secrets.cyberghost-key = {
mode = "0400";
owner = "root";
};
environment.systemPackages = [ pkgs.openvpn ];
# Enable iproute2 for routing tables
networking.iproute2.enable = true;
networking.iproute2.rttablesExtraConfig = ''
100 vpn
'';
# OpenVPN client service - only establishes tunnel, no routing
services.openvpn.servers.cyberghost = {
autoStart = true;
updateResolvConf = false;
config = ''
client
dev tun
proto udp
remote 87-1-hu.cg-dialup.net 443
resolv-retry infinite
nobind
persist-key
persist-tun
# Authentication
auth-user-pass ${config.sops.secrets.cyberghost-auth.path}
ca ${config.sops.secrets.cyberghost-ca.path}
cert ${config.sops.secrets.cyberghost-cert.path}
key ${config.sops.secrets.cyberghost-key.path}
# Security
data-ciphers AES-256-GCM:AES-128-GCM:AES-256-CBC
data-ciphers-fallback AES-256-CBC
auth SHA256
remote-cert-tls server
script-security 2
# Connection
ping 5
explicit-exit-notify 2
# Don't pull any routes - we manage routing ourselves
route-nopull
verb 4
'';
};
# Systemd service to set up VPN routing after tunnel is up
systemd.services.cyberghost-routing = {
description = "CyberGhost VPN routing rules";
after = [ "openvpn-cyberghost.service" ];
requires = [ "openvpn-cyberghost.service" ];
wantedBy = [ "multi-user.target" ];
serviceConfig = {
Type = "oneshot";
RemainAfterExit = true;
ExecStart = pkgs.writeShellScript "vpn-routing-up" ''
# Wait for tun0 to be available
for i in $(seq 1 30); do
if ${pkgs.iproute2}/bin/ip link show tun0 &>/dev/null; then
break
fi
sleep 1
done
# Add default route via VPN tunnel to table vpn
${pkgs.iproute2}/bin/ip route add default dev tun0 table vpn 2>/dev/null || true
# Policy rules (lower number = higher priority)
# VPN server traffic must use main table to avoid routing loop
# Resolve all IPs (hostname has multiple A records for load balancing)
for VPN_SERVER_IP in $(${pkgs.dig}/bin/dig +short ${vpnServer} A); do
${pkgs.iproute2}/bin/ip rule add to $VPN_SERVER_IP table main priority 50 2>/dev/null || true
done
# Local network always uses main routing table
${pkgs.iproute2}/bin/ip rule add to ${localNetwork} table main priority 100 2>/dev/null || true
${pkgs.iproute2}/bin/ip rule add from ${localNetwork} table main priority 100 2>/dev/null || true
# Everything else goes through VPN
${pkgs.iproute2}/bin/ip rule add table vpn priority 200 2>/dev/null || true
'';
ExecStop = pkgs.writeShellScript "vpn-routing-down" ''
${pkgs.iproute2}/bin/ip rule del table vpn priority 200 2>/dev/null || true
${pkgs.iproute2}/bin/ip rule del from ${localNetwork} table main priority 100 2>/dev/null || true
${pkgs.iproute2}/bin/ip rule del to ${localNetwork} table main priority 100 2>/dev/null || true
# Clean up all VPN server IP rules
for VPN_SERVER_IP in $(${pkgs.dig}/bin/dig +short ${vpnServer} A); do
${pkgs.iproute2}/bin/ip rule del to $VPN_SERVER_IP table main priority 50 2>/dev/null || true
done
${pkgs.iproute2}/bin/ip route del default table vpn 2>/dev/null || true
'';
};
};
}