puppet nftables

# manage a ipv4 dnat rule

define nftables::rules::dnat4 (

  Pattern[/^[12]?\d{1,2}\.[12]?\d{1,2}\.[12]?\d{1,2}\.[12]?\d{1,2}$/] $daddr,

  Variant[String,Stdlib::Port] $port,

  Pattern[/^[a-zA-Z0-9_]+$/] $rulename = $title,

  Pattern[/^\d\d$/] $order = '50',

  String[1] $chain = 'default_fwd',

  Optional[String[1]] $iif = undef,

  Enum['tcp','udp'] $proto = 'tcp',

  Optional[Variant[String,Stdlib::Port]] $dport = '',

  Enum['present','absent'] $ensure = 'present',

) {

  $iifname = $iif ? {

    undef   => '',

    default => "iifname ${iif} ",

  }

  $filter_port = $dport ? {

    ''      => $port,

    default => $dport,

  }

  $nat_port = $dport ? {

    ''      => '',

    default => ":${dport}",

  }

  nftables::rule {

    default:

      ensure => $ensure,

      order  => $order;

    "${chain}-${rulename}":

      content => "${iifname}ip daddr ${daddr} ${proto} dport ${filter_port} accept";

    "PREROUTING-${rulename}":

      table   => 'ip-nat',

      content => "${iifname}${proto} dport ${port} dnat to ${daddr}${nat_port}";

  }

}