allow the -p option take a special string "echo", which specifies to send ICMPv6 echo request instead of a UDP packet. this is for test row socket cases.
allow the -p option take a special string "echo", which specifies to
send ICMPv6 echo request instead of a UDP packet.
this is for test row socket cases.

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