def __icmpCheck(self):
icmp = self.__packet[ICMP]
if icmp.type != 8 or len(self.__packet[Raw].load) not in (1, 64):
print 'ICMP check failed'
SNMP.incrementMIB(SNMP_IP_MIB_CODE)
return False
return True
def __checkFragmentedPacket(self, packet):
id = packet[IP].id
if id not in self.__fragmented_packets.keys():
SNMP.incrementMIB(SNMP_FRAG_MIB_CODE)
print 'fail at check frag'
return False
return True
def __checkDefragmentedPacket(self, packet):
offset_val = packet[IP].frag << 3
payload_length = packet[IP].len - 20
if payload_length != packet[UDP].len:
SNMP.incrementMIB(SNMP_IP_MIB_CODE)
print offset_val, payload_length, packet[UDP].len
print 'failed at checking defragmented packet'
return False
return True
def __ipCheck(self):
ip = self.__packet[IP]
# ip layer checks
if ip.version != 4 or ip.ihl != 5 or ip.proto not in (1, 17) or \
ip.chksum == 0:
print 'Ip check failed for packet with id', ip.id
SNMP.incrementMIB(SNMP_IP_MIB_CODE)
return False
return True
def __basicChecks(self, packet):
#fragmentation checks
if packet[IP].flags != 0:
if hasattr(packet.conf_vl, 'port_characteristic'):
if packet.conf_vl.port_characteristic == PORT_SAMPLING:
SNMP.incrementMIB(SNMP_FRAG_MIB_CODE)
return False
return True
if (packet[IP].dst != packet.conf_vl.ip_dst):
SNMP.incrementMIB(SNMP_FRAG_MIB_CODE)
return False
return True
def __udpCheck(self):
packet = self.__packet
port = packet.conf_vl
if packet[UDP].chksum != 0:
print 'packet has no udp checksum as 0'
SNMP.incrementMIB(SNMP_UDP_MIB_CODE)
return False
else:
if port.port_characteristic == PORT_SAMPLING:
if (packet[UDP].len - 8) != port.buffer_size:
print 'Data size != buffer size for packet with Id',\
packet[IP].id
SNMP.incrementMIB(SNMP_UDP_MIB_CODE)
return False
else:
if (packet[UDP].len - 8) > port.buffer_size:
print 'Data size > buffer size for packet with Id', \
packet[IP].id, packet[UDP].len, port.buffer_size
SNMP.incrementMIB(SNMP_UDP_MIB_CODE)
return False
return True
