203 lines
8.2 KiB
Python
203 lines
8.2 KiB
Python
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# This file is part of Scapy
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# Scapy is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 2 of the License, or
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# any later version.
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#
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# Scapy is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with Scapy. If not, see <http://www.gnu.org/licenses/>.
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"""
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Copyright 2012, The MITRE Corporation::
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NOTICE
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This software/technical data was produced for the U.S. Government
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under Prime Contract No. NASA-03001 and JPL Contract No. 1295026
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and is subject to FAR 52.227-14 (6/87) Rights in Data General,
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and Article GP-51, Rights in Data General, respectively.
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This software is publicly released under MITRE case #12-3054
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"""
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# scapy.contrib.description = Licklider Transmission Protocol (LTP)
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# scapy.contrib.status = loads
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import scapy.modules.six as six
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from scapy.packet import Packet, bind_layers, bind_top_down
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from scapy.fields import BitEnumField, BitField, BitFieldLenField, \
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ByteEnumField, ConditionalField, PacketListField, StrLenField
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from scapy.layers.inet import UDP
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from scapy.config import conf
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from scapy.contrib.sdnv import SDNV2, SDNV2FieldLenField
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# LTP https://tools.ietf.org/html/rfc5326
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_ltp_flag_vals = {
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0: '0x0 Red data, NOT (Checkpoint, EORP or EOB)',
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1: '0x1 Red data, Checkpoint, NOT (EORP or EOB)',
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2: '0x2 Red data, Checkpoint, EORP, NOT EOB',
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3: '0x3 Red data, Checkpoint, EORP, EOB',
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4: '0x4 Green data, NOT EOB',
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5: '0x5 Green data, undefined',
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6: '0x6 Green data, undefined',
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7: '0x7 Green data, EOB',
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8: '0x8 Report segment',
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9: '0x9 Report-acknowledgment segmen',
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10: '0xA Control segment, undefined',
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11: '0xB Control segment, undefined',
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12: '0xC Cancel segment from block sender',
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13: '0xD Cancel-acknowledgment segment to block sender',
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14: '0xE Cancel segment from block receiver',
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15: '0xF Cancel-acknowledgment segment to block receiver'}
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_ltp_cancel_reasons = {
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0: 'USR_CNCLD - Client service canceled session.',
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1: 'UNREACH - Unreachable client service.',
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2: 'RLEXC - Retransmission limit exceeded.',
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3: 'MISCOLORED - Received miscolored segment.',
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4: 'SYS_CNCLD - System error condition.',
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5: 'RXMTCYCEXC - Exceeded the retransmission cycles limit.',
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6: 'RESERVED'} # Reserved 0x06-0xFF
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# LTP Extensions https://tools.ietf.org/html/rfc5327
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_ltp_extension_tag = {
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0: 'LTP authentication extension',
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1: 'LTP cookie extension'
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}
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_ltp_data_segment = [0, 1, 2, 3, 4, 5, 6, 7]
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_ltp_checkpoint_segment = [1, 2, 3]
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_ltp_payload_conditions = {}
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def ltp_bind_payload(cls, lambd):
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"""Bind payload class to the LTP packets.
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:param cls: the class to bind
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:param lambd: lambda that will be called to check
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whether or not the cls should be used
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ex: lambda pkt: ...
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"""
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_ltp_payload_conditions[cls] = lambd
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class LTPex(Packet):
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name = "LTP Extension"
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fields_desc = [
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ByteEnumField("ExTag", 0, _ltp_extension_tag),
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SDNV2FieldLenField("ExLength", None, length_of="ExData"),
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# SDNV2FieldLenField
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StrLenField("ExData", "", length_from=lambda x: x.ExLength)
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]
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def default_payload_class(self, pay):
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return conf.padding_layer
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class LTPReceptionClaim(Packet):
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name = "LTP Reception Claim"
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fields_desc = [SDNV2("ReceptionClaimOffset", 0),
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SDNV2("ReceptionClaimLength", 0)]
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def default_payload_class(self, pay):
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return conf.padding_layer
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def _ltp_guess_payload(pkt, *args):
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for k, v in six.iteritems(_ltp_payload_conditions):
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if v(pkt):
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return k
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return conf.raw_layer
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class LTP(Packet):
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name = "LTP"
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fields_desc = [
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BitField('version', 0, 4),
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BitEnumField('flags', 0, 4, _ltp_flag_vals),
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SDNV2("SessionOriginator", 0),
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SDNV2("SessionNumber", 0),
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BitFieldLenField("HeaderExtensionCount", None, 4, count_of="HeaderExtensions"), # noqa: E501
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BitFieldLenField("TrailerExtensionCount", None, 4, count_of="TrailerExtensions"), # noqa: E501
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PacketListField("HeaderExtensions", [], LTPex, count_from=lambda x: x.HeaderExtensionCount), # noqa: E501
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#
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# LTP segments containing data have a DATA header
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#
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ConditionalField(SDNV2("DATA_ClientServiceID", 0),
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lambda x: x.flags in _ltp_data_segment),
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ConditionalField(SDNV2("DATA_PayloadOffset", 0),
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lambda x: x.flags in _ltp_data_segment),
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ConditionalField(SDNV2FieldLenField("DATA_PayloadLength", None, length_of="LTP_Payload"), # noqa: E501
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lambda x: x.flags in _ltp_data_segment),
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#
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# LTP segments that are checkpoints will have a checkpoint serial number and report serial number. # noqa: E501
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#
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ConditionalField(SDNV2("CheckpointSerialNo", 0),
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lambda x: x.flags in _ltp_checkpoint_segment),
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ConditionalField(SDNV2("ReportSerialNo", 0),
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lambda x: x.flags in _ltp_checkpoint_segment),
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#
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# Then comes the actual payload for data carrying segments.
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#
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ConditionalField(PacketListField("LTP_Payload", None, next_cls_cb=_ltp_guess_payload, # noqa: E501
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length_from=lambda x: x.DATA_PayloadLength), # noqa: E501
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lambda x: x.flags in _ltp_data_segment),
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#
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# Report ACKS acknowledge a particular report serial number.
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#
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ConditionalField(SDNV2("RA_ReportSerialNo", 0),
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lambda x: x.flags == 9),
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#
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# Reception reports have the following fields.
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#
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ConditionalField(SDNV2("ReportSerialNo", 0),
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lambda x: x.flags == 8),
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ConditionalField(SDNV2("ReportCheckpointSerialNo", 0),
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lambda x: x.flags == 8),
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ConditionalField(SDNV2("ReportUpperBound", 0),
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lambda x: x.flags == 8),
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ConditionalField(SDNV2("ReportLowerBound", 0),
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lambda x: x.flags == 8),
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ConditionalField(SDNV2FieldLenField("ReportReceptionClaimCount", None, count_of="ReportReceptionClaims"), # noqa: E501
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lambda x: x.flags == 8),
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ConditionalField(PacketListField("ReportReceptionClaims", [], LTPReceptionClaim, # noqa: E501
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count_from=lambda x: x.ReportReceptionClaimCount), # noqa: E501
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lambda x: x.flags == 8 and (not x.ReportReceptionClaimCount or x.ReportReceptionClaimCount > 0)), # noqa: E501
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#
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# Cancellation Requests
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#
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ConditionalField(ByteEnumField("CancelFromSenderReason",
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15, _ltp_cancel_reasons),
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lambda x: x.flags == 12),
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ConditionalField(ByteEnumField("CancelFromReceiverReason",
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15, _ltp_cancel_reasons),
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lambda x: x.flags == 14),
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#
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# Cancellation Acknowldgements
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#
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ConditionalField(SDNV2("CancelAckToBlockSender", 0),
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lambda x: x.flags == 13),
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ConditionalField(SDNV2("CancelAckToBlockReceiver", 0),
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lambda x: x.flags == 15),
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#
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# Finally, trailing extensions
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#
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PacketListField("TrailerExtensions", [], LTPex, count_from=lambda x: x.TrailerExtensionCount) # noqa: E501
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]
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def mysummary(self):
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return self.sprintf("LTP %SessionNumber%"), [UDP]
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bind_top_down(UDP, LTP, sport=1113)
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bind_top_down(UDP, LTP, dport=1113)
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bind_top_down(UDP, LTP, sport=2113)
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bind_top_down(UDP, LTP, dport=2113)
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bind_layers(UDP, LTP, sport=1113, dport=1113)
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