So now I need to hack my traceroute to send ICMP_ECHO_REQUESTS instead
of high-port udp packets?
You'll also need to pursuade your router vendor to violate the ICMP spec,
which says that ICMP error messages (i.e. TTL exceeded) are never sent in
response to ICMP messages...
I suspect that this restriction is precisely the reason that "traceroute" uses
high-port UDP packets.