Unified ping doesn't support IPv4-mapped IPv6 addresses

ping to a mapped address

ping ::ffff:216.58.213.68

sends an ICMPv6 packet out onto the Internet with the mapped address in the destination packet and the IPv6 address as the source. Mapped addresses shouldn't appear on the public internet according to the RFC.

I would have expected this to use the IPv6 API to send an ICMP packet over the v4 Internet on a dual stack machine in accordance with RFC4038.

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: iputils-ping 3:20150815-2ubuntu3
ProcVersionSignature: User Name 4.8.0-30.32-generic 4.8.6
Uname: Linux 4.8.0-30-generic x86_64
ApportVersion: 2.20.3-0ubuntu8
Architecture: amd64
Date: Mon Dec 12 14:27:34 2016
SourcePackage: iputils
UpgradeStatus: No upgrade log present (probably fresh install)