Occasional incorrect inferred target when probing using ICMP6 echo

[robertbeverly]

As reported by Dave Plonka plonka@akamai.com:

"What I've found is that some [IPv6] routers will respond with an echo reply to an echo request destined for a host on their LAN."

ICMP6 echo responses only quote the ECHO probe payload (not the full IPv6 packet). Thus, yarrp assumes that ICMP6 echo responses originate from the target that was probed. In the above case (when a different IPv6 source is sending responses), yarrp incorrect outputs the probed target as the responding proxy.