#!/usr/sbin/nft -f

<%- unless @interfaces.empty? %>
define external-interfaces = { <%= @interfaces.sort.uniq.join(", ") %> }
<%- end %>

define ip-private-addresses = { 0.0.0.0, 10.0.0.0/8, 127.0.0.0/8, 169.254.0.0/16, 172.16.0.0/12, 192.0.2.0/24, 192.168.0.0/16, 224.0.0.0/4 }
define ip6-private-addresses = { 2001:db8::/32, fc00::/7, ff00::/8 }

table inet chef-filter {
  set ip-osm-addresses {
    type ipv4_addr
<%- unless Array(@hosts["inet"]).empty? %>
    elements = { <%= Array(@hosts["inet"]).sort.join(", ") %> }
<%- end %>
  }

  set ip6-osm-addresses {
    type ipv6_addr
<%- unless Array(@hosts["inet"]).empty? %>
    elements = { <%= Array(@hosts["inet6"]).sort.join(", ") %> }
<%- end %>
  }

  set ip-blocklist {
    type ipv4_addr
    flags interval
  }

  set ip6-blocklist {
    type ipv6_addr
    flags interval
  }

  set ratelimit-icmp-echo-ip {
    type ipv4_addr
    flags dynamic
    timeout 120s
  }

  set ratelimit-icmp-echo-ip6 {
    type ipv6_addr
    flags dynamic
    timeout 120s
  }

<%- node[:networking][:firewall][:sets].each do |set| %>
  set <%= set %> {
<%- if set.end_with?("-ip") %>
    type ipv4_addr
<%- elsif set.end_with?("-ip6") %>
    type ipv6_addr
<%- end %>
    flags dynamic
<%- unless set.start_with?("connlimit-") %>
    timeout 120s
<%- end %>
  }

<%- end %>
  chain log-and-drop {
    limit rate 1/second log
    drop
  }

  chain log-and-reject {
    limit rate 1/second log
    reject
  }

  chain incoming {
<%- if node[:networking][:firewall][:allowlist].empty? %>
    ip saddr { $ip-private-addresses } jump log-and-drop
<%- else %>
    ip saddr { $ip-private-addresses } ip saddr != { <%= node[:networking][:firewall][:allowlist].sort.join(", ") %> } jump log-and-drop
<%- end %>
    ip6 saddr { $ip6-private-addresses } jump log-and-drop

    ip saddr @ip-blocklist jump log-and-drop
    ip6 saddr @ip6-blocklist jump log-and-drop

    ct state { established, related } accept

    icmp type { destination-unreachable } accept
    icmp type { echo-request } update @ratelimit-icmp-echo-ip { ip saddr limit rate 1/second } accept
    icmp type { echo-request } drop

    icmpv6 type { nd-neighbor-solicit, nd-neighbor-advert, nd-router-solicit, nd-router-advert } accept
    icmpv6 type { echo-request } update @ratelimit-icmp-echo-ip6 { ip6 saddr limit rate 1/second } accept
    icmpv6 type { echo-request } drop

    meta l4proto { icmp, icmpv6 } jump log-and-drop

    tcp flags & (fin|syn|rst|psh|ack|urg) == fin|psh|urg jump log-and-drop
    tcp flags & (fin|syn|rst|psh|ack|urg) == 0x0 jump log-and-drop
    tcp flags & (syn|rst) == syn|rst jump log-and-drop
    tcp flags & (fin|rst) == fin|rst jump log-and-drop
    tcp flags & (fin|syn) == fin|syn jump log-and-drop
    tcp flags & (fin|psh|ack) == fin|psh jump log-and-drop
    tcp sport 0 tcp flags & (fin|syn|rst|ack) == syn jump log-and-drop

<%- node[:networking][:firewall][:incoming].uniq.each do |rule| %>
    <%= rule %>
<%- end %>

    jump log-and-drop
  }

  chain outgoing {
<%- if node[:networking][:firewall][:allowlist].empty? %>
    ip daddr { $ip-private-addresses } jump log-and-drop
<%- else %>
    ip daddr { $ip-private-addresses } ip daddr != { <%= node[:networking][:firewall][:allowlist].sort.join(", ") %> } jump log-and-drop
<%- end %>
    ip6 daddr { $ip6-private-addresses } jump log-and-drop

<%- node[:networking][:firewall][:outgoing].each do |rule| %>
    <%= rule %>
<%- end %>

    accept
  }

  chain input {
    type filter hook input priority filter;

<%- unless @interfaces.empty? %>
    iifname { $external-interfaces } jump incoming
<%- end %>

    accept
  }

  chain forward {
    type filter hook forward priority filter;

<%- unless @interfaces.empty? %>
    iifname { $external-interfaces } jump incoming
    oifname { $external-interfaces } jump outgoing
<%- end %>

    accept
  }

  chain output {
    type filter hook output priority filter;

<%- unless @interfaces.empty? %>
    oifname { $external-interfaces } jump outgoing
<%- end %>

    accept
  }
}
<%- if node[:roles].include?("gateway") %>

table ip chef-nat {
  chain postrouting {
    type nat hook postrouting priority srcnat;

<%- node.interfaces(:role => :external, :family => :inet).each do |external| %>
<%- node.interfaces(:role => :internal, :family => :inet).each do |internal| %>
    oifname { <%= external[:interface] %> } ip saddr { <%= internal[:network] %>/<%= internal[:prefix] %> } snat <%= external[:address] %>
<%- end %>
<%- end %>
  }
}
<%- end %>