bird.conf.j2

#jinja2: trim_blocks: "true", lstrip_blocks: "true"
{% set V6_SADR_DEFAULT_ROUTE = '::/0 from ' ~ freifunk_global_prefix %}
log syslog all;
debug protocols {states};

# Include additional bird config files for runtime extendability
include "/dev/shm/bird_*.conf";

protocol device { };

##
## Kernel <-> Babel tables
##

ipv6 sadr table v6_main;
ipv4 table v4_main;
ipv4 table v4_babel_ff;
ipv4 table v4_babel_default;


protocol kernel kernel_v6_main {
	ipv6 sadr {
		table v6_main;
		import all;
		export all;
	};
	learn all; # Allow learning loopback route
}

# Currently not in use due to OLSRD->Babel migration
# For now babel IPv4 routes land in the subsequent KRTs
protocol kernel kernel_v4_main {
	ipv4 {
		table v4_main;
		import none;
		export none;
	};
}

protocol kernel kernel_v4_babel_ff {
	kernel table 10;
	ipv4 {
		table v4_babel_ff;
		import none;
		export all;
	};
}

protocol pipe pipe_v4_main_to_babel_ff {
	table v4_main;
	peer table v4_babel_ff;
	export where net != 0.0.0.0/0;
	import none;
}

protocol kernel kernel_v4_babel_default {
	kernel table 11;
	ipv4 {
		table v4_babel_default;
		import none;
		export all;
	};
}

protocol pipe pipe_v4_main_to_babel_default {
	table v4_main;
	peer table v4_babel_default;
	export where net = 0.0.0.0/0;
	import none;
}

##
## Uplink static IPv4 route
##
{% if uplink['ipv4'] | ansible.utils.ipaddr('prefix') >= 30 %}
  {% set v4_nexthop =  uplink['ipv4'] | ansible.utils.ipaddr('peer') %}
{% else %}
  {% set v4_nexthop =  uplink['ipv4'] | ansible.utils.ipaddr('1') | ansible.utils.ipaddr('address') %}
{%- endif %}

protocol static static_uplink {
	ipv4 { table v4_main; };
	check link;
	route 0.0.0.0/0 via {{ v4_nexthop }} dev "{{ uplink['ifname'] }}";
}

##
## Babel Section
##

protocol babel babel_mesh {
	randomize router id yes;
	ipv6 sadr {
		table v6_main;
		# Import only /56 location aggregates and default routes
		import filter {
			if ! (net.len = 56 || net = {{ V6_SADR_DEFAULT_ROUTE }}) then reject;
{% for interface in mesh_links %}
			if ifname = "{{ interface['ifname'] }}" then {
			  babel_metric = babel_metric + {{ interface.get('mesh_metric', mesh_metric_default_in) }};
			  accept;
			}
{% endfor %}
			if ifname ~ "wg_*" then {
			  babel_metric = babel_metric + {{ mesh_metric_tunnel_in }};
			  accept;
			}
			accept;
		};
		export where source = RTS_BABEL || net = {{ ipv6_prefix }} from ::/0 || net = {{ V6_SADR_DEFAULT_ROUTE }};
	};
	ipv4 {
		table v4_main;
		import filter {
			if ifname ~ "gre4-*" then reject;
{% for interface in mesh_links %}
			if ifname = "{{ interface['ifname'] }}" then {
			  babel_metric = babel_metric + {{ interface.get('mesh_metric', mesh_metric_default_in) }};
			  accept;
			}
{% endfor %}
			if ifname ~ "wg_*" then {
			  babel_metric = babel_metric + {{ mesh_metric_tunnel_in }};
			  accept;
			}
			accept;
		};
		export where source = RTS_BABEL || net = 0.0.0.0/0; # Readvertise Babel routes and advertise default route
	};

	# Mesh interfaces
{% for interface in mesh_links %}
	interface "{{ interface['ifname'] }}" {
		type wireless;
	};
{% endfor %}

	# GRE Tunnels
{% for gateway in groups['role_gateway'] | difference([inventory_hostname]) | sort %}
	interface "gre4-{{ hostvars[gateway]['gre_tunnel_alias'] }}" {
		type wireless;
		rxcost {{ gre_metric }}; # Keep for now, could be implemented as export filter later
	};
{% endfor %}

    # Wireguard tunnel links which are dynamically established
	interface "wg_*" {
		type wireless;
		rxcost {{ mesh_metric_tunnel_in }}; # Keep for now, could be implemented as export filter later
	};
}


{% if 'ipv6' in uplink %}
##
## BGP Section
##
ipv6 table v6_bgp_upstream;

# Define local attribute as yet another safetynet to ensure that we dont announce the bgpdisco
# routes to our upstream which will likely make the internet explode.
# While that sounds funny that aint a joke - Take it very serious or risk our trust!!
attribute int really_announce_to_upstream;


# Attention. Following rules are redundant for good reasons.
# 1. Let only pass routes which carry the really_announce_to_upstream route attribute being true
# 2. Filter for networks we explicitly would like to advertise, configurable through group_vars.
# Please do not remove those and pay attention, because we are abusing BGP for really funky stuff
# in our Backbone. Those routes must never reach the internet, otherwise it might break. Not kidding!
filter bgp_export_aggregates {
	# See 1.
	if ! ( defined( really_announce_to_upstream ) && really_announce_to_upstream = 1312 ) then reject;

	# See 2.
	if net !~ [ {{ freifunk_global_prefix }}{{ '{' }}{{ freifunk_wahlkreis_announcement_prefix }},{{ freifunk_wahlkreis_announcement_prefix}}{{ '}' }} ] then reject;

	# Allow Traffic Engineering on routes which made it until here.
	include "/dev/shm/announcement*.bird.conf";

	accept;
}

protocol static static_v6_bgp_upstream {
	ipv6 { table v6_bgp_upstream; };
{% for wahlkreis in freifunk_wahlkreis_prefixes %}
  {% for no in range(0, wahlkreis | ansible.utils.ipsubnet(freifunk_wahlkreis_announcement_prefix) | int) %}
	route {{ wahlkreis | ansible.utils.ipsubnet(freifunk_wahlkreis_announcement_prefix, no) }} unreachable {
		really_announce_to_upstream = 1312;
	};
  {% endfor %}
{% endfor %}
}

protocol bgp bgp_upstream {
	local {{ uplink['ipv6'] | ansible.utils.ipaddr('address') }} as {{ local_asn }};
	neighbor {{ uplink['ipv6'] | ansible.utils.ipaddr('peer') }} as {{ peer_asn }};
	ipv6 {
		table v6_bgp_upstream;
		import where net = ::/0;
		export filter bgp_export_aggregates;
	};
}

##
## Hack to announce create a source specifc default route pointing to BGP Next Hop
## Details: https://github.com/freifunk-berlin/bbb-configs/issues/1062#issuecomment-2466541315
##
ipv6 sadr table v6_default_via_bgp;

protocol static static_v6_default_via_bgp {
	ipv6 sadr { table v6_default_via_bgp; };
	igp table v6_bgp_upstream; # Where to lookup recursive resolved next-hop
	route {{ V6_SADR_DEFAULT_ROUTE }} recursive ::;
}

protocol pipe pipe_v6_default_via_bgp_to_main {
	table v6_default_via_bgp;
	peer table v6_main;
	export where dest != RTD_UNREACHABLE;
	import none;
}
{% endif %}