host_firewall: pass LAPI client flows from wt0 to the pod port with their own address

host_firewall/defaults/main.yml

@@ -34,6 +34,11 @@ firewall:
     ifaces: {}
     v4: {}
     v6: {}
+    # Hosts outside the ring that reach a NodePort service (CrowdSec LAPI) over wt0, and the port of its pods: Cilium
+    # translates the NodePort before netfilter, so the flows arrive as client -> pod:port.
+    lapi:
+      port: null
+      clients: {}
   # IPv4 port forwards: name -> {daddr, to, tcp: ports, udp: ports}, ports as in
   # the maps above. Forwarded traffic passes the forward hook, not input.
   dnat: {}

host_firewall/templates/host.nft.j2

@@ -30,6 +30,8 @@ set {{ name }} {
 {% set guest_match = 'iifname { "' ~ (guest_ifaces | join('", "')) ~ '" }' %}
 {% set dnat = firewall.dnat | default({}, true) | dict2items | rejectattr('value', 'none') | map(attribute='value') | list %}
 {% set masquerade = firewall.masquerade | default({}, true) | dict2items | rejectattr('value', 'none') | map(attribute='value') | unique | list %}
+{% set lapi = cluster.lapi | default({}, true) %}
+{% set lapi_rule = list(lapi.clients) and lapi.port %}
 {% set scrapers = firewall.scrapers | default({}, true) %}
 {% set forward_guard = firewall.forward_guard | default({}, true) | dict2items | rejectattr('value', 'none') | list %}
 {% set blocklists = firewall.spamhaus or firewall.firehol %}
@@ -91,6 +93,9 @@ table inet host {
 	{{ addr_set('admin_v6', 'ipv6_addr', firewall.admin.v6) }}
 	{{ addr_set('cluster_v4', 'ipv4_addr', cluster.v4) }}
 	{{ addr_set('cluster_v6', 'ipv6_addr', cluster.v6) }}
+{% if lapi_rule %}
+	{{ addr_set('lapi_clients_v4', 'ipv4_addr', lapi.clients) }}
+{% endif %}
 	{{ addr_set('scrapers_v4', 'ipv4_addr', scrapers.v4) }}
 	{{ addr_set('scrapers_v6', 'ipv6_addr', scrapers.v6) }}
 	{{ addr_list_set('rl_exempt_v4', 'ipv4_addr', exempt_v4) }}
@@ -132,10 +137,15 @@ table inet host {
 	# the host stack (veth with legacy host routing). This chain runs right after. Flows from the cluster ring (pods,
 	# node NetBird addresses) into the pod CIDR arriving on wt0 get mark 0x1bd20: not masqueraded, and accepted by the
 	# NetBird forward filter, which drops forwarded wt0 traffic that no route group allows. Other pod to pod flows
-	# lose their marks.
+	# lose their marks. The same mark lets the LAPI clients (@lapi_clients_v4) reach the pod port of the NodePort service
+	# with their own address: Cilium has translated the NodePort before this point, so NetBird would masquerade the flow
+	# to the cilium_host address and the network policy would see world.
 	chain pod_identity {
 		type filter hook prerouting priority -140; policy accept;
 		iifname "wt0" ct state new ip saddr @cluster_v4 ip daddr {{ cluster.v4.pods }} meta mark set 0x0001bd20
+{% if lapi_rule %}
+		iifname "wt0" ct state new ip saddr @lapi_clients_v4 ip daddr {{ cluster.v4.pods }} tcp dport {{ lapi.port }} meta mark set 0x0001bd20
+{% endif %}
 		ct state new ip saddr {{ cluster.v4.pods }} ip daddr {{ cluster.v4.pods }} meta mark 0x0001bd21 meta mark set 0
 		ct state new ip saddr {{ cluster.v4.pods }} ip daddr {{ cluster.v4.pods }} meta mark 0x0001bd22 meta mark set 0
 	}