class LTPex(Packet):
name = "LTP Extension"
fields_desc = [
ByteEnumField("ExTag", 0, _ltp_extension_tag),
SDNV2FieldLenField("ExLength", None, length_of="ExData"),
# SDNV2FieldLenField
StrLenField("ExData", "", length_from=lambda x: x.ExLength)
]
def default_payload_class(self, pay):
return conf.padding_layer
class BPBLOCK(Packet):
fields_desc = [ByteEnumField('Type', 1, {1: "Bundle payload block"}),
SDNV2('ProcFlags', 0),
SDNV2FieldLenField('BlockLen', None, length_of="load"),
StrLenField("load", "",
length_from=lambda pkt: pkt.BlockLen,
max_length=65535)
]
def mysummary(self):
return self.sprintf("BPBLOCK(%Type%) Flags: %ProcFlags% Len: %BlockLen%") # noqa: E501
class LTP(Packet):
name = "LTP"
fields_desc = [
BitField('version', 0, 4),
BitEnumField('flags', 0, 4, _ltp_flag_vals),
SDNV2("SessionOriginator", 0),
SDNV2("SessionNumber", 0),
BitFieldLenField("HeaderExtensionCount",
None,
4,
count_of="HeaderExtensions"), # noqa: E501
BitFieldLenField("TrailerExtensionCount",
None,
4,
count_of="TrailerExtensions"), # noqa: E501
PacketListField(
"HeaderExtensions", [],
LTPex,
count_from=lambda x: x.HeaderExtensionCount), # noqa: E501
#
# LTP segments containing data have a DATA header
#
ConditionalField(SDNV2("DATA_ClientServiceID", 0),
lambda x: x.flags in _ltp_data_segment),
ConditionalField(SDNV2("DATA_PayloadOffset", 0),
lambda x: x.flags in _ltp_data_segment),
ConditionalField(
SDNV2FieldLenField("DATA_PayloadLength",
None,
length_of="LTP_Payload"), # noqa: E501
lambda x: x.flags in _ltp_data_segment),
#
# LTP segments that are checkpoints will have a checkpoint serial number and report serial number. # noqa: E501
#
ConditionalField(SDNV2("CheckpointSerialNo", 0),
lambda x: x.flags in _ltp_checkpoint_segment),
ConditionalField(SDNV2("ReportSerialNo", 0),
lambda x: x.flags in _ltp_checkpoint_segment),
#
# Then comes the actual payload for data carrying segments.
#
ConditionalField(
PacketListField(
"LTP_Payload",
None,
next_cls_cb=_ltp_guess_payload, # noqa: E501
length_from=lambda x: x.DATA_PayloadLength), # noqa: E501
lambda x: x.flags in _ltp_data_segment),
#
# Report ACKS acknowledge a particular report serial number.
#
ConditionalField(SDNV2("RA_ReportSerialNo", 0),
lambda x: x.flags == 9),
#
# Reception reports have the following fields.
#
ConditionalField(SDNV2("ReportSerialNo", 0), lambda x: x.flags == 8),
ConditionalField(SDNV2("ReportCheckpointSerialNo", 0),
lambda x: x.flags == 8),
ConditionalField(SDNV2("ReportUpperBound", 0), lambda x: x.flags == 8),
ConditionalField(SDNV2("ReportLowerBound", 0), lambda x: x.flags == 8),
ConditionalField(
SDNV2FieldLenField("ReportReceptionClaimCount",
None,
count_of="ReportReceptionClaims"), # noqa: E501
lambda x: x.flags == 8),
ConditionalField(
PacketListField(
"ReportReceptionClaims",
[],
LTPReceptionClaim, # noqa: E501
count_from=lambda x: x.ReportReceptionClaimCount
), # noqa: E501
lambda x: x.flags == 8 and
(not x.ReportReceptionClaimCount or x.ReportReceptionClaimCount > 0
)), # noqa: E501
#
# Cancellation Requests
#
ConditionalField(
ByteEnumField("CancelFromSenderReason", 15, _ltp_cancel_reasons),
lambda x: x.flags == 12),
ConditionalField(
ByteEnumField("CancelFromReceiverReason", 15, _ltp_cancel_reasons),
lambda x: x.flags == 14),
#
# Cancellation Acknowldgements
#
ConditionalField(SDNV2("CancelAckToBlockSender", 0),
lambda x: x.flags == 13),
ConditionalField(SDNV2("CancelAckToBlockReceiver", 0),
lambda x: x.flags == 15),
#
# Finally, trailing extensions
#
PacketListField("TrailerExtensions", [],
LTPex,
count_from=lambda x: x.TrailerExtensionCount
) # noqa: E501
]
def mysummary(self):
return self.sprintf("LTP %SessionNumber%"), [UDP]