I can see that icmp_echo_request, icmp_reply, flow_summary and
icmp_unreachable event handlers work. But icmp_sent doesn't work. I just put
print statement in each of these handlers, only icmp_sent didn't print
anything. Any idea about this problem? thanks
icmp_sent is a generic event, only generated for ICMPs for which there's
not a more specific analyzer. So you won't see it for echo request/reply,
time exceeded, or unreachables.