отправить ICMP ECHO_REQUEST на сетевые узлы (send ICMP ECHO_REQUEST to network hosts)
ICMP PACKET DETAILS
An IP header without options is 20 bytes. An ICMP ECHO_REQUEST
packet contains an additional 8 bytes worth of ICMP header
followed by an arbitrary amount of data. When a packetsize is
given, this indicates the size of this extra piece of data (the
default is 56). Thus the amount of data received inside of an IP
packet of type ICMP ECHO_REPLY will always be 8 bytes more than
the requested data space (the ICMP header).
If the data space is at least of size of struct timeval ping uses
the beginning bytes of this space to include a timestamp which it
uses in the computation of round trip times. If the data space is
shorter, no round trip times are given.
