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#!/usr/sbin/nft -f
# Start with clean NAT table
flush table nat
{% if helper_functions == '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 == '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 VYATTA_CT_HELPER
{{ base_command }} OUTPUT position {{ out_ct_ignore }} counter jump VYATTA_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 %}
{% macro nat_rule(rule, chain) %}
{% set src_addr = "ip saddr " + rule.source_address if rule.source_address %}
{% set dst_addr = "ip daddr " + rule.dest_address if rule.dest_address %}
{# negated port groups need special treatment, move != in front of { } group #}
{% if rule.source_port.startswith('!=') %}
{% set src_port = "sport != { " + rule.source_port.replace('!=','') +" }" if rule.source_port %}
{% else %}
{% set src_port = "sport { " + rule.source_port +" }" if rule.source_port %}
{% endif %}
{# negated port groups need special treatment, move != in front of { } group #}
{% if rule.dest_port.startswith('!=') %}
{% set dst_port = "dport != { " + rule.dest_port.replace('!=','') +" }" if rule.dest_port %}
{% else %}
{% set dst_port = "dport { " + rule.dest_port +" }" if rule.dest_port %}
{% endif %}
{% set comment = "DST-NAT-" + rule.number %}
{% if chain == "PREROUTING" %}
{% set interface = " iifname \"" + rule.interface_in + "\"" %}
{% set trns_addr = "dnat to " + rule.translation_address %}
{% elif chain == "POSTROUTING" %}
{% set interface = " oifname \"" + rule.interface_out + "\"" %}
{% if rule.translation_address == 'masquerade' %}
{% set trns_addr = rule.translation_address %}
{% if rule.translation_port %}
{% set trns_addr = trns_addr + " to " %}
{% endif %}
{% else %}
{% set trns_addr = "snat to " + rule.translation_address %}
{% endif %}
{% endif %}
{% set trns_port = ":" + rule.translation_port if rule.translation_port %}
{% if rule.protocol == "tcp_udp" %}
{% set protocol = "tcp" %}
{% set comment = comment + " tcp_udp" %}
{% else %}
{% set protocol = rule.protocol %}
{% endif %}
{% if rule.log %}
{% set base_log = "[NAT-DST-" + rule.number %}
{% if rule.exclude %}
{% set log = base_log + "-EXCL]" %}
{% elif rule.translation_address == 'masquerade' %}
{% set log = base_log + "-MASQ]" %}
{% else %}
{% set log = base_log + "]" %}
{% endif %}
{% endif %}
{% if rule.exclude %}
{# rule has been marked as "exclude" thus we simply return here #}
{% set trns_addr = "return" %}
{% set trns_port = "" %}
{% endif %}
{% set output = "add rule ip nat " + chain + interface %}
{% if protocol != "all" %}
{% set output = output + " ip protocol " + protocol %}
{% endif %}
{% if src_addr %}
{% set output = output + " " + src_addr %}
{% endif %}
{% if src_port %}
{% set output = output + " " + protocol + " " + src_port %}
{% endif %}
{% if dst_addr %}
{% set output = output + " " + dst_addr %}
{% endif %}
{% if dst_port %}
{% 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 %}
{% set log_output = output + " log prefix \"" + log + "\" comment \"" + comment + "\"" %}
{% endif %}
{% if trns_addr %}
{% set output = output + " " + trns_addr %}
{% endif %}
{% if trns_port %}
{# 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 comment %}
{% set output = output + " comment \"" + comment + "\"" %}
{% endif %}
{{ log_output if log_output }}
{{ output }}
{# Special handling if protocol is tcp_udp, we must repeat the entire rule with udp as protocol #}
{% if rule.protocol == "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 }}
{{ output | replace("tcp ", "udp ") }}
{% endif %}
{% endmacro %}
#
# Destination NAT rules build up here
#
{% for rule in destination if not rule.disabled -%}
{{ nat_rule(rule, 'PREROUTING') }}
{% endfor %}
#
# Source NAT rules build up here
#
{% for rule in source if not rule.disabled -%}
{{ nat_rule(rule, 'POSTROUTING') }}
{% endfor %}
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