make sure we always check dstoptlen < IP6OPT_MINLEN. "options MIP6" was vulnerable.
make sure we always check dstoptlen < IP6OPT_MINLEN.
"options MIP6" was vulnerable.

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