def encode(self):
data = struct.pack('!BBHHH', self.type, self.code, 0, self.id, self.sequence_number)
data += self.data
checksum = struct.pack('H', internet_checksum(data))
data = data[:2] + checksum + data[4:]
return data
from pynetstack.utils import internet_checksum
from pynetstack.tests.data import icmp_packet
from binascii import hexlify, unhexlify
import struct
icmp_packet = unhexlify(icmp_packet)
checksum = icmp_packet[2:4]
print 'excepted checksum: %s' % hexlify(checksum)
data = icmp_packet[:2] + '\0' * 2 + icmp_packet[4:]
res = internet_checksum(data)
if res == checksum:
print 'checksum ok'
else:
print 'checksum wrong'
if internet_checksum(icmp_packet) == struct.pack('!H', 0x0000):
print 'checksum ok'
else:
print 'checksum wrong'