*** ICMPHDR - IP (Internet Protocol) Header
*
* +------+------+-------------+---------------------------+
* 0 |:PTYPE|:PCODE| ICMPCHKS | ICMPSPEC |
* +------+------+-------------+---------------------------+
* 8 | |
* = ICMPDATA =
* | +---------------------------+
* | | 1FC
* +---------------------------+
*
*** ICMPHDR - IP (Internet Protocol) Header
*** Overlay for ICMPSPEC in ICMPHDR
*
* +-------------+-------------+
* 0 ... 4 | ICMPIDNO | ICMPSQNO |
* +-------------+-------------+
* 8
*
*** Overlay for ICMPSPEC in ICMPHDR
*** Overlay for ICMPSPEC in ICMPHDR
*
* +------+------+-------------+
* 0 ... 4 |:PV4NU|:PV4LN| ICMP4MTU |
* +------+------+-------------+
* 8
*
*** Overlay for ICMPSPEC in ICMPHDR
*** Overlay for ICMPSPEC in ICMPHDR
*
* +------+------+-------------+
* 0 ... 4 |:PV6LN|//////| ICMP6MTU |
* +------+------+-------------+
* 8
*
*** Overlay for ICMPSPEC in ICMPHDR
|