paulbsd-salt/states/nftables/templates/rules.nft.j2

## {{ salt['pillar.get']('salt_managed', default='Salt Managed') }}

{%- from "nftables/map.jinja" import nftables with context %}
{%- from "nftables/map.jinja" import net with context %}

## IPv4 filtering
add table ip filter
add chain ip filter INPUT { type filter hook input priority 0; policy drop; }
add chain ip filter FORWARD { type filter hook forward priority 0; policy accept; }
add chain ip filter OUTPUT { type filter hook output priority 0; policy accept; }
add chain ip filter DOCKER
add rule ip filter INPUT iifname lo counter accept
add rule ip filter INPUT iifname tun* counter accept
add rule ip filter INPUT iifname br* counter accept
add rule ip filter INPUT iifname veth* counter accept
add rule ip filter INPUT ct state related,established counter accept
add rule ip filter INPUT ip protocol icmp counter accept
{%- for network in net.ip_networks+net.optional_ip_networks %}
{%- if '.' in network %}
add rule ip filter INPUT ip saddr {{ network }} ct state established,new counter accept
{%- endif %}
{%- endfor %}
{%- for port in net.public_ports %}
add rule ip filter INPUT {{ port.split('/')[0] }} dport {{ port.split('/')[1] }} ct state established,new counter accept
{%- endfor %}
{%- if nftables.log %}
add rule ip filter INPUT counter log
{%- endif %}


## IPv4 NAT
add table ip nat
add chain ip nat PREROUTING { type nat hook prerouting priority dstnat; policy accept; }
add chain ip nat INPUT { type nat hook input priority 1; policy accept; }
add chain ip nat OUTPUT { type nat hook output priority -100; policy accept; }
add chain ip nat POSTROUTING { type nat hook postrouting priority srcnat; policy accept; }
add chain ip nat DOCKER

### Main NAT rules
{%- for network in net.nats %}
add rule ip nat POSTROUTING ip saddr {{ network }} counter masquerade
{%- endfor %}

### Docker related rules
add rule ip nat POSTROUTING oifname != "docker0" ip saddr 172.17.0.0/24 counter masquerade
add rule ip nat PREROUTING fib daddr type local counter jump DOCKER
add rule ip nat OUTPUT ip daddr != 127.0.0.0/8 fib daddr type local counter jump DOCKER
add rule ip nat POSTROUTING iifname br-* counter masquerade
add rule ip nat POSTROUTING iifname veth-* counter masquerade

add rule ip nat DOCKER iifname "docker0" counter return

## IPv6 filtering
add table ip6 filter6
add chain ip6 filter6 INPUT { type filter hook input priority 0; policy drop; }
add chain ip6 filter6 FORWARD { type filter hook forward priority 0; policy accept; }
add chain ip6 filter6 OUTPUT { type filter hook output priority 0; policy accept; }
add rule ip6 filter6 INPUT iifname lo counter accept
add rule ip6 filter6 INPUT iifname tun* counter accept
add rule ip6 filter6 INPUT ct state related,established counter accept
add rule ip6 filter6 INPUT icmpv6 type {destination-unreachable, packet-too-big, time-exceeded, echo-request, echo-reply, mld-listener-query, mld-listener-report, mld-listener-reduction, nd-router-solicit, nd-router-advert, nd-neighbor-solicit, nd-neighbor-advert, nd-redirect, parameter-problem, router-renumbering} accept
{%- for network in net.ip_networks %}
{%- if ':' in network %}
add rule ip6 filter6 INPUT ip6 saddr {{ network }} ct state established,new counter accept
{%- endif %}
{%- endfor %}
{%- for port in net.public_ports %}
add rule ip6 filter6 INPUT {{ port.split('/')[0] }} dport {{ port.split('/')[1] }} ct state established,new counter accept
{%- endfor %}
{%- if nftables.log %}
add rule ip6 filter6 INPUT counter log
{%- endif %}

## Endline is mandatory