node: Remove permanent ARP entry when remote node is deleted
node: Remove permanent ARP entry when remote node is deleted

When IPsec or NodePort is enabled, we add a permanent ARP entry (remote
node IP => remote node MAC addr) upon receiving a NodeUpdate event.
The entry is needed to facilitate calls to fib_lookup() from the
datapath.

Up until now, the permanent entry was not removed when the remote node
was deleted. This could lead to a problem, when a packet destined to a
new node which reused the IP addr of the deleted node was dropped due to
the wrong MAC addr until NodeUpdate event for the new node had been
received.

This commit fixes the problem by removing obsolete ARP entries.

Signed-off-by: Martynas Pumputis <6b0d31c0d563223024da45691584643ac78c96e8@lambda.lt>

cilium-team/cilium,michi-covalent/cilium,tgraf/cilium,cilium/cilium,tklauser/cilium,cilium/cilium,cilium/cilium,tklauser/cilium,tgraf/cilium,tklauser/cilium,michi-covalent/cilium,michi-covalent/cilium,tklauser/cilium,tgraf/cilium,tgraf/cilium,michi-covalent/cilium,cilium-team/cilium,tklauser/cilium,tgraf/cilium,michi-covalent/cilium,tgraf/cilium,cilium/cilium,cilium/cilium