* sys/netinet6/icmp6.c: (netbsd only for now) try to prevent   DoS attack using path MTU messages.  validate ICMPv6 too big messages   using content of TCP/UDP connection table and/or IPsec SAs.   framework by thorpej@netbsd.org.  sync with netbsd-current.
* sys/netinet6/icmp6.c: (netbsd only for now) try to prevent
  DoS attack using path MTU messages.  validate ICMPv6 too big messages
  using content of TCP/UDP connection table and/or IPsec SAs.
  framework by thorpej@netbsd.org.  sync with netbsd-current.

MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame