#!/usr/sbin/nft -f

{% macro nat_rule(rule, config, chain) %}
{%   set comment  = '' %}
{%   set base_log = '' %}
{%   set src_addr  = 'ip saddr ' ~ config.source.address.replace('!','!= ') if config.source.address is vyos_defined %}
{%   set dst_addr  = 'ip daddr ' ~ config.destination.address.replace('!','!= ') if config.destination.address is vyos_defined %}
{#   negated port groups need special treatment, move != in front of { } group #}
{%   if config.source.port is vyos_defined and config.source.port.startswith('!=') %}
{%     set src_port  = 'sport != { ' ~ config.source.port.replace('!=','') ~ ' }' %}
{%   else %}
{%     set src_port  = 'sport { ' ~ config.source.port ~ ' }' if config.source.port is vyos_defined %}
{%   endif %}
{#   negated port groups need special treatment, move != in front of { } group #}
{%   if config.destination.port is vyos_defined and config.destination.port.startswith('!=') %}
{%     set dst_port  = 'dport != { ' ~ config.destination.port.replace('!=','') ~ ' }' %}
{%   else %}
{%     set dst_port  = 'dport { ' ~ config.destination.port ~ ' }' if config.destination.port is vyos_defined %}
{%   endif %}
{%   if chain is vyos_defined('PREROUTING') %}
{%     set comment   = 'DST-NAT-' ~ rule %}
{%     set base_log  = '[NAT-DST-' ~ rule %}
{%     set interface = ' iifname "' ~ config.inbound_interface ~ '"' if config.inbound_interface is vyos_defined and config.inbound_interface is not vyos_defined('any') else '' %}
{%     if config.translation.address is vyos_defined %}
{#       support 1:1 network translation #}
{%       if config.translation.address | is_ip_network %}
{%         set trns_addr = 'dnat ip prefix to ip daddr map { ' ~ config.destination.address ~ ' : ' ~ config.translation.address ~ ' }' %}
{#         we can now clear out the dst_addr part as it's already covered in aboves map #}
{%         set dst_addr  = '' %}
{%       else %}
{%         set trns_addr = 'dnat to ' ~ config.translation.address %}
{%       endif %}
{%     endif %}
{%   elif chain is vyos_defined('POSTROUTING') %}
{%     set comment   = 'SRC-NAT-' ~ rule %}
{%     set base_log  = '[NAT-SRC-' ~ rule %}
{%     set interface = ' oifname "' ~ config.outbound_interface ~ '"' if config.outbound_interface is vyos_defined and config.outbound_interface is not vyos_defined('any') else '' %}
{%     if config.translation.address is vyos_defined %}
{%       if config.translation.address is vyos_defined('masquerade') %}
{%         set trns_addr = config.translation.address %}
{%         if config.translation.port is vyos_defined %}
{%           set trns_addr = trns_addr ~ ' to ' %}
{%         endif %}
{#       support 1:1 network translation #}
{%       elif config.translation.address | is_ip_network %}
{%         set trns_addr = 'snat ip prefix to ip saddr map { ' ~ config.source.address ~ ' : ' ~ config.translation.address ~ ' }' %}
{#         we can now clear out the src_addr part as it's already covered in aboves map #}
{%         set src_addr  = '' %}
{%       else %}
{%         set trns_addr = 'snat to ' ~ config.translation.address %}
{%       endif %}
{%     endif %}
{%   endif %}
{%   set trns_port = ':' ~ config.translation.port if config.translation.port is vyos_defined %}
{#   protocol has a default value thus it is always present #}
{%   if config.protocol is vyos_defined('tcp_udp') %}
{%     set protocol  = 'tcp' %}
{%     set comment   = comment ~ ' tcp_udp' %}
{%   else %}
{%     set protocol  = config.protocol %}
{%   endif %}
{%   if config.log is vyos_defined %}
{%     if config.exclude is vyos_defined %}
{%       set log = base_log ~ '-EXCL]' %}
{%     elif config.translation.address is vyos_defined('masquerade') %}
{%       set log = base_log +'-MASQ]' %}
{%     else %}
{%       set log = base_log ~ ']' %}
{%     endif %}
{%   endif %}
{%   if config.exclude is vyos_defined %}
{#     rule has been marked as 'exclude' thus we simply return here #}
{%     set trns_addr = 'return' %}
{%     set trns_port = '' %}
{%   endif %}
{#   T1083: NAT address and port translation options #}
{%   if config.translation.options is vyos_defined %}
{%     if config.translation.options.address_mapping is vyos_defined('persistent') %}
{%         set trns_opts_addr  = 'persistent' %}
{%     endif %}
{%     if config.translation.options.port_mapping is vyos_defined('random') %}
{%       set trns_opts_port  = 'random' %}
{%     elif config.translation.options.port_mapping is vyos_defined('fully-random') %}
{%       set trns_opts_port  = 'fully-random' %}
{%     endif %}
{%   endif %}
{%   if trns_opts_addr is vyos_defined and trns_opts_port is vyos_defined %}
{%     set trns_opts  = trns_opts_addr ~ ',' ~ trns_opts_port %}
{%   elif trns_opts_addr is vyos_defined %}
{%     set trns_opts  = trns_opts_addr %}
{%   elif trns_opts_port is vyos_defined %}
{%     set trns_opts  = trns_opts_port %}
{%   endif %}
{%   set output = 'add rule ip nat ' ~ chain ~ interface %}
{%   if protocol is not vyos_defined('all') %}
{%     set output = output ~ ' ip protocol ' ~ protocol %}
{%   endif %}
{%   if src_addr is vyos_defined %}
{%     set output = output ~ ' ' ~ src_addr %}
{%   endif %}
{%   if src_port is vyos_defined %}
{%     set output = output ~ ' ' ~ protocol ~ ' ' ~ src_port %}
{%   endif %}
{%   if dst_addr is vyos_defined %}
{%     set output = output ~ ' ' ~ dst_addr %}
{%   endif %}
{%   if dst_port is vyos_defined %}
{%     set output = output ~ ' ' ~ protocol ~ ' ' ~ dst_port %}
{%   endif %}
{#   Count packets #}
{%   set output = output ~ ' counter' %}
{#   Special handling of log option, we must repeat the entire rule before the #}
{#   NAT translation options are added, this is essential                      #}
{%   if log is vyos_defined %}
{%     set log_output = output ~ ' log prefix "' ~ log ~ '" comment "' ~ comment ~ '"' %}
{%   endif %}
{%   if trns_addr is vyos_defined %}
{%     set output = output ~ ' ' ~ trns_addr %}
{%   endif %}
{%   if trns_port is vyos_defined %}
{#     Do not add a whitespace here, translation port must be directly added after IP address #}
{#     e.g. 192.0.2.10:3389                                                                   #}
{%     set output = output ~ trns_port %}
{%   endif %}
{%   if trns_opts is vyos_defined %}
{%     set output = output ~ ' ' ~ trns_opts %}
{%   endif %}
{%   if comment is vyos_defined %}
{%     set output = output ~ ' comment "' ~ comment ~ '"' %}
{%   endif %}
{{ log_output if log_output is vyos_defined}}
{{ output }}
{#   Special handling if protocol is tcp_udp, we must repeat the entire rule with udp as protocol #}
{%   if config.protocol is vyos_defined('tcp_udp') %}
{#     Beware of trailing whitespace, without it the comment tcp_udp will be changed to udp_udp #}
{{ log_output | replace('tcp ', 'udp ') if log_output is vyos_defined }}
{{ output | replace('tcp ', 'udp ') }}
{%   endif %}
{% endmacro %}

# Start with clean SNAT and DNAT chains
flush chain ip nat PREROUTING
flush chain ip nat POSTROUTING
{% if helper_functions is vyos_defined('remove') %}
{# NAT if going to be disabled - remove rules and targets from nftables #}
{%   set base_command = 'delete rule ip raw' %}
{{ base_command }} PREROUTING handle {{ pre_ct_ignore }}
{{ base_command }} OUTPUT     handle {{ out_ct_ignore }}
{{ base_command }} PREROUTING handle {{ pre_ct_conntrack }}
{{ base_command }} OUTPUT     handle {{ out_ct_conntrack }}

delete chain ip raw NAT_CONNTRACK

{% elif helper_functions is vyos_defined('add') %}
{# NAT if enabled - add targets to nftables #}
add chain ip raw NAT_CONNTRACK
add rule ip raw NAT_CONNTRACK counter accept
{%   set base_command = 'add rule ip raw' %}
{{ base_command }} PREROUTING position {{ pre_ct_ignore }}    counter jump VYOS_CT_HELPER
{{ base_command }} OUTPUT     position {{ out_ct_ignore }}    counter jump VYOS_CT_HELPER
{{ base_command }} PREROUTING position {{ pre_ct_conntrack }} counter jump NAT_CONNTRACK
{{ base_command }} OUTPUT     position {{ out_ct_conntrack }} counter jump NAT_CONNTRACK
{% endif %}

#
# Destination NAT rules build up here
#
add rule ip nat PREROUTING counter jump VYOS_PRE_DNAT_HOOK
{% if destination.rule is vyos_defined %}
{%   for rule, config in destination.rule.items() if config.disable is not vyos_defined %}
{{ nat_rule(rule, config, 'PREROUTING') }}
{%   endfor %}
{% endif %}
#
# Source NAT rules build up here
#
add rule ip nat POSTROUTING counter jump VYOS_PRE_SNAT_HOOK
{% if source.rule is vyos_defined %}
{%   for rule, config in source.rule.items() if config.disable is not vyos_defined %}
{{ nat_rule(rule, config, 'POSTROUTING') }}
{%   endfor %}
{% endif %}