add docs

docs/src/topics/firewalling.md

@@ -112,10 +112,12 @@ spec:
       ports: "1-65535"
       protocol: "TCP"
       addressSetRefs:  # Can be used together with .addresses if desired.
-        - name: example-addrset
+        - name: vpc-addrset
           kind: AddressSet
   inboundRuleRefs:  # Can be used together with .inboundRules if desired
-    - name: example-fwrule
+    - name: example-fwrule-udp
+      kind: FirewallRule
+    - name: example-fwrule-icmp
       kind: FirewallRule
   # outboundRules: []
   # outboundRuleRefs: []
@@ -132,7 +134,7 @@ spec:
 apiVersion: infrastructure.cluster.x-k8s.io/v1alpha2
 kind: FirewallRule
 metadata:
-  name: example-fwrule
+  name: example-fwrule-udp
 spec:
   action: ACCEPT
   label: intra-cluster-udp
@@ -141,6 +143,18 @@ spec:
   addresses:
     ipv4:
       - "10.0.0.0/8"
+---
+apiVersion: infrastructure.cluster.x-k8s.io/v1alpha2
+kind: FirewallRule
+metadata:
+  name: example-fwrule-icmp
+spec:
+  action: ACCEPT
+  label: intra-cluster-icmp
+  protocol: "ICMP"
+  addressSetRefs:  # Can be used together with .addresses if desired.
+    - name: vpc-addrset
+      kind: AddressSet
 ```
 
 ### Cloud Firewall Machine Integration