+ def assert_packet_checksums_valid(self, packet,
+ ignore_zero_udp_checksums=True):
+ udp_layers = ['UDP', 'UDPerror']
+ checksum_fields = ['cksum', 'chksum']
+ checksums = []
+ counter = 0
+ temp = packet.__class__(str(packet))
+ while True:
+ layer = temp.getlayer(counter)
+ if layer:
+ for cf in checksum_fields:
+ if hasattr(layer, cf):
+ if ignore_zero_udp_checksums and \
+ 0 == getattr(layer, cf) and \
+ layer.name in udp_layers:
+ continue
+ delattr(layer, cf)
+ checksums.append((counter, cf))
+ else:
+ break
+ counter = counter + 1
+ temp = temp.__class__(str(temp))
+ for layer, cf in checksums:
+ self.assert_equal(getattr(packet[layer], cf),
+ getattr(temp[layer], cf),
+ "packet checksum on layer #%d: %s" % (
+ layer, temp[layer].name))
+
+ def assert_checksum_valid(self, received_packet, layer,
+ field_name='chksum',
+ ignore_zero_checksum=False):
+ """ Check checksum of received packet on given layer """
+ received_packet_checksum = getattr(received_packet[layer], field_name)
+ if ignore_zero_checksum and 0 == received_packet_checksum:
+ return
+ recalculated = received_packet.__class__(str(received_packet))
+ delattr(recalculated[layer], field_name)
+ recalculated = recalculated.__class__(str(recalculated))
+ self.assert_equal(received_packet_checksum,
+ getattr(recalculated[layer], field_name),
+ "packet checksum on layer: %s" % layer)
+
+ def assert_ip_checksum_valid(self, received_packet,
+ ignore_zero_checksum=False):
+ self.assert_checksum_valid(received_packet, 'IP',
+ ignore_zero_checksum=ignore_zero_checksum)
+
+ def assert_tcp_checksum_valid(self, received_packet,
+ ignore_zero_checksum=False):
+ self.assert_checksum_valid(received_packet, 'TCP',
+ ignore_zero_checksum=ignore_zero_checksum)
+
+ def assert_udp_checksum_valid(self, received_packet,
+ ignore_zero_checksum=True):
+ self.assert_checksum_valid(received_packet, 'UDP',
+ ignore_zero_checksum=ignore_zero_checksum)
+
+ def assert_embedded_icmp_checksum_valid(self, received_packet):
+ if received_packet.haslayer(IPerror):
+ self.assert_checksum_valid(received_packet, 'IPerror')
+ if received_packet.haslayer(TCPerror):
+ self.assert_checksum_valid(received_packet, 'TCPerror')
+ if received_packet.haslayer(UDPerror):
+ self.assert_checksum_valid(received_packet, 'UDPerror',
+ ignore_zero_checksum=True)
+ if received_packet.haslayer(ICMPerror):
+ self.assert_checksum_valid(received_packet, 'ICMPerror')
+
+ def assert_icmp_checksum_valid(self, received_packet):
+ self.assert_checksum_valid(received_packet, 'ICMP')
+ self.assert_embedded_icmp_checksum_valid(received_packet)
+
+ def assert_icmpv6_checksum_valid(self, pkt):
+ if pkt.haslayer(ICMPv6DestUnreach):
+ self.assert_checksum_valid(pkt, 'ICMPv6DestUnreach', 'cksum')
+ self.assert_embedded_icmp_checksum_valid(pkt)
+ if pkt.haslayer(ICMPv6EchoRequest):
+ self.assert_checksum_valid(pkt, 'ICMPv6EchoRequest', 'cksum')
+ if pkt.haslayer(ICMPv6EchoReply):
+ self.assert_checksum_valid(pkt, 'ICMPv6EchoReply', 'cksum')
+