Log Message:
Import dhcpcd-7.2.2 with the following changes:
  *  DHCP: Ensure dhcp is running on the interface received from
  *  BSD: Link handling has been simplified, however it is expected
     that if an interface supports SIOCGIFMEDIA then it reports
     the correct link status via route(4) for reliable operations
  *  BPF: ARP filter is more robust
  *  BSD and sun: Validate RTM message lengths

This security issue has been addressed
  *  DHCPv6: Fix a potential read overflow with D6_OPTION_PD_EXCLUDE

Many thanks to Maxime Villard <max@m00nbsd.net> for discovering this issue.