On a router with many routes, charon uses always 100% CPU. This results in packet loss, at least of tunneled packets.
Use case: A full table BGP router that is also endpoint for specific connections.
Route count on a router (which has this error):
vyos@rz2a-gw5# run show ip route summary Route Source Routes FIB (vrf default) connected 4 4 ospf 208 204 ebgp 0 0 ibgp 879186 879177 ------ Totals 879398 879385
While researching, i found out there appear many rt_netlink drops in the log, which i'd associate with the count of routes. And they change often as it's the nature of full BGP route tables. Charon itself logs nothing.