sendPacket.py cannot send the correct icmp package

[MidCheck]

issue

The checksum is not calculated before sendto, and the activation package is discarded when used across network segments in docker.

patch

import array
packet = header + data
words = array.array('h', pakcet)
pkt_checksum = 0
for word in words:
    pkt_checksum += (word & 0xffff)
pkt_checksum = (pkt_checksum >> 16) + (pkt_checksum & 0xffff)
pkt_checksum += (pkt_checksum >> 16)
pkt_checksum = (~pkt_checksum) & 0xffff

header = struct.pack("bbHHh", ICMP_ECHO_REQUEST, 0, pkt_checksum, pkt_id, 1)

Insert these codes into line 54 of sendPacket.py