#!/usr/sbin/nft -f
#
# /etc/nftables.conf - FFHO packet filter configuration
#
{%- set nodes = salt['pillar.get']('nodes', {}) %}
{%- set node_config = nodes.get (grains['id'], {}) %}
{%- set roles = node_config.get ('roles', []) %}

{%- set fw_config = salt['pillar.get']('firewall', {}) %}
{%- set admin_access = fw_config.get ('admin_access') %}
{%- set ssh = fw_config.get ('ssh') %}
{%- set monitoring_cfg = salt['pillar.get']('monitoring') %}
{%- set monitoring_rules = salt['ffho_netfilter.generate_monitoring_rules'](nodes, grains['id'], monitoring_cfg) %}
{%- set services = salt['ffho_netfilter.generate_service_rules'](fw_config, node_config) %}
{%- set forward = salt['ffho_netfilter.generate_forward_policy'](fw_config, node_config) %}
{%- set nat_policy = salt['ffho_netfilter.generate_nat_policy'](node_config) %}
{%- set mgmt_config = salt['ffho_netfilter.generate_mgmt_config'](fw_config, node_config) %}
{%- set urpf = salt['ffho_netfilter.generate_urpf_policy'](node_config) %}
{%- set ospf_ifaces = salt['ffho_netfilter.get_ospf_active_interface'](node_config) %}
{%- set vxlan_ifaces = salt['ffho_netfilter.get_vxlan_interfaces'](node_config['ifaces']) %}
{%- set bgp_peers = salt['ffho_netfilter.get_bgp_peers']() %}

flush ruleset

table ip filter {
{%- if bgp_peers[4]|length > 0 %}
	set ibgp-peers {
		type ipv4_addr
		elements = {
  {%- for ip, name in bgp_peers[4].items () %}
			{{ ip }},	# {{ name }}
  {%- endfor %}
		}
	}
{%- endif %}

	chain input {
		type filter hook input priority 0; policy drop;
		iifname "lo" counter accept
		udp dport 0 counter drop
		tcp dport 7 counter drop comment "Ignore echo protocol queries"
{%- if vxlan_ifaces %}
		udp dport 4789 jump vxlan
{%- endif %}
{%- if urpf %}
		jump urpf
{%- endif %}
		ip protocol icmp jump icmp_chain
		ct state invalid counter drop
		jump admin_access
		jump monitoring
		tcp dport 22 counter jump ssh
{%- if ospf_ifaces %}
		{#- ifname sets are introduced in nftables 2.11 #}
		meta l4proto ospf iifname { {{ ospf_ifaces|join(', ') }} } counter accept
{%- endif %}
{%- if bgp_peers[4]|length > 0  %}
		tcp dport 179 counter jump bgp
{%- endif %}
		ct state related,established counter accept
		jump services
		meta pkttype broadcast counter drop comment "Drop broadcasts before logging"
		limit rate 1/second burst 3 packets counter log prefix "nf input: "
		limit rate 1/second burst 3 packets counter reject with icmp type admin-prohibited
		counter drop
	}

	chain forward {
		type filter hook forward priority 0; policy {{ forward['policy'] }}; # {{ forward['policy_reason'] }}
{%- if urpf %}
		jump urpf
{%- endif %}
{%- if mgmt_config and mgmt_config['prefixes'][4] %}
		ip daddr { {{ mgmt_config['prefixes'][4]|join(', ') }} } oifname { {{ mgmt_config['ifaces']|join(', ') }} } jump mgmt
{%- endif %}
{%- for rule in forward['rules'].get ('4', []) %}
		{{ rule }}
{%- endfor %}

{%- if forward['policy'] == 'drop' %}
		limit rate 1/second burst 3 packets counter log prefix "nf forward: "
		limit rate 1/second burst 3 packets counter reject with icmp type admin-prohibited
{%- endif %}
	}

	chain icmp_chain {
		icmp type { echo-request, destination-unreachable, time-exceeded } counter accept
	}

	chain admin_access {
{%- for pfx in admin_access[4].keys()|sort %}
  {%- set comment = admin_access[4][pfx] %}
		ip saddr {{ pfx }} counter accept comment "{{ comment }}"
{%- endfor %}
	}

{%- if 'router' in roles %}
	chain bgp {
		ip saddr @ibgp-peers counter accept comment "iBGP peers"
		# TODO: Add external BGP peers, if any
	}
{%- endif %}

{%- if mgmt_config %}
	chain mgmt {
		ct state related,established counter accept
		jump admin_access
		jump icmp_chain
		jump monitoring
		jump log-reject
	}
{%- endif %}

	chain monitoring {
{%- for rule in monitoring_rules[4] %}
		{{ rule }}
{%- endfor %}
	}

	chain ssh {
{%- for pfx in ssh[4].keys()|sort %}
  {%- set comment = ssh[4][pfx] %}
		ip saddr {{ pfx }} counter accept comment "{{ comment }}"
{%- endfor %}
	}

	chain services {
{%- for rule in services[4] %}
		{{ rule }}
{%- endfor %}
	}

{%- if urpf %}
	chain urpf {
  {%- for iface_cfg in urpf  %}
    {%- for pfx in iface_cfg[4] %}
		iifname {{ iface_cfg['iface'] }} ip saddr {{ pfx }} return
    {%- endfor %}
		iifname {{ iface_cfg['iface'] }} counter drop
  {%- endfor %}
	}
{%- endif %}

{%- if vxlan_ifaces %}
	chain vxlan {
  {%- for iface in vxlan_ifaces %}
		iifname {{ iface }} accept
  {%- endfor %}
		counter drop
	}
{%- endif %}

	chain log-drop {
		limit rate 1/second burst 3 packets counter log prefix "netfilter: "
		counter drop
	}

	chain log-reject {
		limit rate 1/second burst 3 packets counter log prefix "netfilter: "
		limit rate 1/second burst 3 packets counter reject with icmp type admin-prohibited
		counter drop
	}
}

table ip6 filter {
{%- if bgp_peers[6]|length > 0 %}
	set ibgp-peers {
		type ipv6_addr
		elements = {
  {%- for ip, name in bgp_peers[6].items () %}
			{{ ip }},	# {{ name }}
  {%- endfor %}
		}
	}
{%- endif %}

	chain input {
		type filter hook input priority 0; policy drop;
		iifname "lo" counter accept
		tcp dport 7 counter drop comment "Ignore echo protocol queries"
{%- if vxlan_ifaces %}
		udp dport 4789 jump vxlan
{%- endif %}
{%- if urpf %}
		jump urpf
{%- endif %}
		meta l4proto icmpv6 jump icmp_chain
		ct state invalid counter drop
		jump admin_access
		jump monitoring
		tcp dport 22 counter jump ssh
{%- if ospf_ifaces %}
		{#- ifname sets are introduced in nftables 2.11 #}
		meta l4proto ospf iifname { {{ ospf_ifaces|join(', ') }} } counter accept
{%- endif %}
{%- if bgp_peers[6]|length > 0  %}
		tcp dport 179 counter jump bgp
{%- endif %}
		ct state related,established counter accept
		counter jump services
		limit rate 1/second burst 3 packets counter log prefix "netfilter: "
		limit rate 1/second burst 3 packets counter reject with icmpv6 type admin-prohibited
		counter drop
	}

	chain forward {
		type filter hook forward priority 0; policy {{ forward['policy'] }}; # {{ forward['policy_reason'] }}
{%- if urpf %}
		jump urpf
{%- endif %}
{%- for rule in forward['rules'].get ('6', []) %}
		{{ rule }}
{%- endfor %}

{%- if forward['policy'] == 'drop' %}
		limit rate 1/second burst 3 packets counter log prefix "nf forward: "
		limit rate 1/second burst 3 packets counter reject with icmpv6 type admin-prohibited
{%- endif %}
	}

	chain icmp_chain {
		icmpv6 type { destination-unreachable, packet-too-big, time-exceeded, parameter-problem, echo-request, echo-reply } counter accept
		icmpv6 type { nd-router-solicit, nd-router-advert, nd-neighbor-solicit, nd-neighbor-advert, ind-neighbor-solicit, ind-neighbor-advert } ip6 hoplimit 255 counter accept
		icmpv6 type { mld-listener-query, mld-listener-report, mld-listener-reduction } ip6 saddr fe80::/64 counter accept
	}

	chain admin_access {
{%- for pfx in admin_access[6].keys()|sort %}
  {%- set comment = admin_access[6][pfx] %}
		ip6 saddr {{ pfx }} counter accept comment "{{ comment }}"
{%- endfor %}
	}

{%- if 'router' in roles %}
	chain bgp {
		ip6 saddr @ibgp-peers counter accept comment "iBGP peers"
		# TODO: Add external BGP peers, if any
	}
{%- endif %}

	chain monitoring {
{%- for rule in monitoring_rules[6] %}
		{{ rule }}
{%- endfor %}
	}

	chain ssh {
{%- for pfx in ssh[6].keys()|sort %}
  {%- set comment = ssh[6][pfx] %}
		ip6 saddr {{ pfx }} counter accept comment "{{ comment }}"
{%- endfor %}
	}

	chain services {
{%- for rule in services[6] %}
		{{ rule }}
{%- endfor %}
	}

{%- if urpf %}
	chain urpf {
		ip6 saddr fe80::/64 return
  {%- for iface_cfg in urpf  %}
    {%- for pfx in iface_cfg[6] %}
		iifname {{ iface_cfg['iface'] }} ip6 saddr {{ pfx }} return
    {%- endfor %}
		iifname {{ iface_cfg['iface'] }} counter drop
  {%- endfor %}
	}
{%- endif %}

{%- if vxlan_ifaces %}
	chain vxlan {
  {%- for iface in vxlan_ifaces %}
		iifname {{ iface }} accept
  {%- endfor %}
		counter drop
	}
{%- endif %}

	chain log-drop {
		limit rate 1/second burst 3 packets counter log prefix "netfilter: "
		counter drop
	}

	chain log-reject {
		limit rate 1/second burst 3 packets counter log prefix "netfilter: "
		limit rate 1/second burst 3 packets counter reject with icmpv6 type admin-prohibited
		counter drop
	}
}

{#-
 # NAT
 #}
{%- for af in [ 4, 6 ] %}
  {%- if nat_policy[af] %}
    {%- set af_name = "ip" if af == 4 else "ip6" %}
table {{ af_name }} nat {
    {%- for chain in ['output', 'prerouting', 'postrouting'] if chain in nat_policy[af] %}
	chain {{ chain }} {
		type nat hook {{ chain }} priority 0; policy accept;
      {%- for rule in nat_policy[af][chain] %}
		{{ rule }}
      {%- endfor %}
	}
    {%- endfor %}
}
  {%- endif %}
{%- endfor %}