# Allow connections to public ports on the host
@def &allow_local($proto, $port) = {
  domain (ip ip6) table filter chain INPUT protocol $proto dport $port ACCEPT;
}

# Defines a service residing in a given container
@def &def_service($service, $container, $proto, $port) = {
  # look up IP addresses of the container
  @def $ip4 = @resolve("$container.$search_domain", A);
  @def $ip6 = @resolve("ipv6.$container.$search_domain", AAAA);
  @def $ula = @resolve("ula.$container.$search_domain", AAAA);

  # chain to allow forwarding to the service
  domain (ip ip6) table filter chain @cat("allow_", $service) daddr @ipfilter(($ip4 $ip6 $ula)) protocol $proto dport $port ACCEPT;

  # chain to do the DNAT to change the address / port to the one of the container / service
  domain ip  table nat chain @cat("fwd_to_", $service) protocol $proto DNAT to "$ip4:$port";
  domain ip6 table nat chain @cat("fwd_to_", $service) protocol $proto DNAT to "[$ip6]:$port";
}


# Forwards a public port to the given service
@def &forward_to_service($service, $proto, $port) = {
  domain (ip ip6) {
    # allow forwarding to the service
    table filter chain FORWARD jump @cat("allow_", $service);

    table nat {
      # change destination address / port to the one of the container / service
      chain PREROUTING interface $internet protocol $proto dport $port jump @cat("fwd_to_", $service);
    }
  }
}

# Allows connection from the given container to the specified service (which resides in another container)
@def &allow_service_for($service, $container) = {
  @def $ip4 = @resolve("$container.$search_domain", A);
  @def $ip6 = @resolve("ipv6.$container.$search_domain", AAAA);
  @def $ula = @resolve("ula.$container.$search_domain", AAAA);
  domain (ip ip6) table filter chain FORWARD saddr @ipfilter(($ip4 $ip6 $ula)) jump @cat("allow_", $service);
}

# Allows connection a specific service to all containers
@def &allow_service_for_all($service) = {
  domain (ip ip6) table filter chain FORWARD interface $bridge jump @cat("allow_", $service);
}

# ----------------
# currently unused

@def &forward_to($container, $proto, $port) = {
  # look up IP addresses of the container
  @def $ip4 = @resolve($container.$search_domain, A);
  @def $ip6 = @resolve("ipv6.$container.$search_domain", AAAA);
  @def $ula = @resolve("ula.$container.$search_domain", AAAA);

  domain (ip ip6) {
    # allow forwarding to container
    table filter chain FORWARD daddr @ipfilter(($ip4 $ip6 $ula)) protocol $proto dport $port ACCEPT;

    # change destination address to the containers one
    table nat chain PREROUTING interface $internet protocol $proto dport $port DNAT to @ipfilter($ip4 $ip6 $ula);
  }
}