define icmp_protos = {ipv6-icmp, icmp, igmp}

table arp filter {
  limit lim_arp {
    rate over 50 mbytes/second burst 50 mbytes
  }

  counter arp-rx {}
  counter arp-tx {}

  counter arp-ratelimit-rx {}
  counter arp-ratelimit-tx {}

  chain input {
    type filter hook input priority filter
    policy accept

    limit name lim_arp counter name arp-ratelimit-rx drop

    counter name arp-rx
  }

  chain output {
    type filter hook output priority filter
    policy accept

    limit name lim_arp counter name arp-ratelimit-tx drop

    counter name arp-tx
  }
}

table inet filter {
  limit lim_reject {
    rate over 1000/second burst 1000 packets
  }

  limit lim_icmp {
    rate over 50 mbytes/second burst 50 mbytes
  }

  counter invalid-fw {}
  counter fw-lo {}
  counter fw-printer {}
  counter fw-host {}

  counter icmp-ratelimit-fw {}

  counter reject-ratelimit-fw {}
  counter reject-fw {}
  counter reject-tcp-fw {}
  counter reject-icmp-fw {}

  counter drop-fw {}

  counter invalid-rx {}

  counter rx-lo {}
  counter invalid-local4-rx {}
  counter invalid-local6-rx {}

  counter icmp-ratelimit-rx {}
  counter icmp-rx {}

  counter cups-rx {}

  counter established-rx {}

  counter reject-ratelimit-rx {}
  counter reject-rx {}
  counter reject-tcp-rx {}
  counter reject-icmp-rx {}

  counter drop-rx {}

  counter tx-lo {}

  counter icmp-ratelimit-tx {}
  counter icmp-tx {}

  counter cups-tx {}

  counter tx {}

  chain forward {
    type filter hook forward priority filter
    policy drop


    ct state invalid log level debug prefix "drop invalid forward: " counter name invalid-fw drop


    iifname lo counter name fw-lo accept


    meta l4proto $icmp_protos limit name lim_icmp counter name icmp-ratelimit-fw drop
    meta l4proto $icmp_protos counter name icmp-fw accept


    iifname printer oifname eth0 ip daddr 10.141.4.0 meta l4proto . th dport { tcp . 53, udp . 53, udp . 123 } counter fw-printer accept
    iifname printer oifname eth0 ip6 daddr 2a03:4000:52:ada:4:: meta l4proto . th dport { tcp . 53, udp . 53, udp . 123 } counter fw-printer accept
    iifname eth0 oifname printer counter fw-host accept


    limit name lim_reject log level debug prefix "drop forward: " counter name reject-ratelimit-fw drop
    log level debug prefix "reject forward: " counter name reject-fw
    meta l4proto tcp ct state new counter name reject-tcp-fw reject with tcp reset
    ct state new counter name reject-icmp-fw reject


    counter name drop-fw
  }

  chain input {
    type filter hook input priority filter
    policy drop


    ct state invalid log level debug prefix "drop invalid input: " counter name invalid-rx drop


    iifname lo counter name rx-lo accept
    iif != lo ip daddr 127.0.0.1/8 counter name invalid-local4-rx reject
    iif != lo ip6 daddr ::1/128 counter name invalid-local6-rx reject

    meta l4proto $icmp_protos limit name lim_icmp counter name icmp-ratelimit-rx drop
    meta l4proto $icmp_protos counter name icmp-rx accept


    ip6 saddr 2a03:4000:52:ada:4:: tcp dport 631 counter name cups-rx accept
    ip saddr 10.141.4.0 tcp dport 631 counter name cups-rx accept

    ct state {established, related} counter name established-rx accept


    limit name lim_reject log level debug prefix "drop input: " counter name reject-ratelimit-rx drop
    log level debug prefix "reject input: " counter name reject-rx
    meta l4proto tcp ct state new counter name reject-tcp-rx reject with tcp reset
    ct state new counter name reject-icmp-rx reject


    counter name drop-rx
  }

  chain output {
    type filter hook output priority filter
    policy accept


    oifname lo counter name tx-lo accept

    meta l4proto $icmp_protos limit name lim_icmp counter name icmp-ratelimit-tx drop
    meta l4proto $icmp_protos counter name icmp-tx accept


    tcp sport 631 counter name cups-tx accept


    counter name tx
  }
}

table ip nat {
  counter host-nat {}

  chain postrouting {
    type nat hook postrouting priority srcnat
    policy accept


    oifname eth0 counter name host-nat masquerade
  }
}

table ip mss_clamp {
  counter host-mss-clamp {}

  chain postrouting {
    type filter hook postrouting priority mangle
    policy accept


    oifname eth0 tcp flags & (syn|rst) == syn counter name host-mss-clamp tcp option maxseg size set rt mtu
  }
}