class StatusReport(CborArray):
''' The Status Report of BPbis Section 6.1.1.
'''
@enum.unique
class ReasonCode(enum.IntEnum):
NO_INFO = 0 # "No additional information"
LIFETIME_EXP = 1 # "Lifetime expired"
FWD_UNI = 2 # "Forwarded over unidirectional link"
TX_CANCEL = 3 # "Transmission canceled"
DEPLETE_STORAGE = 4 # "Depleted storage"
DEST_EID_UNINTEL = 5 # "Destination endpoint ID unintelligible"
NO_ROUTE = 6 # "No known route to destination from here"
NO_NEXT_CONTACT = 7 # "No timely contact with next node on route"
BLOCK_UNINTEL = 8 # "Block unintelligible"
HOP_LIMIT_EXC = 9 # "Hop limit exceeded"
TRAFIC_PAIRED = 10 # "Traffic pared"
UNKNOWN_SEC = 13 # "Unknown Security Operation"
FAILED_SEC = 15 # "Failed Security Operation"
fields_desc = (
PacketField('status', default=StatusInfoArray(), cls=StatusInfoArray),
EnumField('reason_code', default=ReasonCode.NO_INFO, enum=ReasonCode),
EidField('subj_source'),
PacketField('subj_ts', default=Timestamp(), cls=Timestamp),
OptionalField(UintField('fragment_offset'), ),
OptionalField(UintField('payload_len'), ),
)
class AbstractSecurityBlock(CborSequence):
''' Block data from 'draft-ietf-dtn-bpsec-22' Section 3.6.
'''
@enum.unique
class Flag(enum.IntFlag):
''' Security flags.
Flags must be in LSbit-first order.
'''
NONE = 0
PARAMETERS_PRESENT = 2**0
fields_desc = (
ArrayWrapField(
FieldListField('targets', default=[], fld=UintField('block_num'))),
UintField('context_id'),
FlagsField('context_flags', default=Flag.NONE, flags=Flag),
EidField('source'),
ConditionalField(
ArrayWrapField(
PacketListField('parameters', default=None,
cls=TypeValuePair), ),
lambda block: block.getfieldval('context_flags') &
AbstractSecurityBlock.Flag.PARAMETERS_PRESENT),
ArrayWrapField(
PacketListField('results', default=[], cls=TargetResultList), ),
)
class HopCountBlock(CborArray):
''' Block data from BPbis Section 4.3.3.
'''
fields_desc = (
UintField('limit'),
UintField('count'),
)
class PrimaryBlock(AbstractBlock):
''' The primary block definition '''
@enum.unique
class Flag(enum.IntFlag):
''' Bundle flags.
'''
NONE = 0
#: bundle deletion status reports are requested.
REQ_DELETION_REPORT = 0x040000
#: bundle delivery status reports are requested.
REQ_DELIVERY_REPORT = 0x020000
#: bundle forwarding status reports are requested.
REQ_FORWARDING_REPORT = 0x010000
#: bundle reception status reports are requested.
REQ_RECEPTION_REPORT = 0x004000
#: status time is requested in all status reports.
REQ_STATUS_TIME = 0x000040
#: user application acknowledgement is requested.
USER_APP_ACK = 0x000020
#: bundle must not be fragmented.
NO_FRAGMENT = 0x000004
#: payload is an administrative record.
PAYLOAD_ADMIN = 0x000002
#: bundle is a fragment.
IS_FRAGMENT = 0x000001
fields_desc = (
UintField('bp_version', default=7),
FlagsField('bundle_flags', default=Flag.NONE, flags=Flag),
EnumField('crc_type', default=AbstractBlock.CrcType.NONE, enum=AbstractBlock.CrcType),
EidField('destination'),
EidField('source'),
EidField('report_to'),
PacketField('create_ts', default=Timestamp(), cls=Timestamp),
UintField('lifetime', default=0),
ConditionalField(
UintField('fragment_offset', default=0),
lambda block: block.getfieldval('bundle_flags') & PrimaryBlock.Flag.IS_FRAGMENT
),
ConditionalField(
UintField('total_app_data_len', default=0),
lambda block: block.getfieldval('bundle_flags') & PrimaryBlock.Flag.IS_FRAGMENT
),
ConditionalField(
BstrField('crc_value'),
lambda block: block.getfieldval('crc_type') != 0
),
)
def testAddfield(self):
fld = FieldListField('field', [], UintField('field'))
s_init = [0, 'hi']
val = [1, 2]
s_final = fld.addfield(None, s_init, val)
self.assertEqual(s_final, [0, 'hi', 1, 2])
def testGetfield(self):
fld = FieldListField('field', [], UintField('field'))
s_init = [1, 2]
(s_final, val) = fld.getfield(None, s_init)
self.assertEqual(s_final, [])
self.assertEqual(val, [1, 2])
class TypeValuePair(CborArray):
''' A pattern for an array encoding which contains exactly two values.
'''
fields_desc = (
UintField('type_code'),
CborField('value'),
)
class Timestamp(CborArray):
''' A structured representation of an DTN Timestamp.
The timestamp is a two-tuple of (time, sequence number)
The creation time portion is automatically converted from a
:py:cls:`datetime.datetime` object and text.
'''
fields_desc = (
DtnTimeField('dtntime', default=0),
UintField('seqno', default=0),
)
def testDecode(self):
fld = UintField('field')
self.assertEqual(fld.m2i(None, 0), 0)
self.assertEqual(fld.m2i(None, 10), 10)
with self.assertRaises(ValueError):
fld.m2i(None, 'hi')
def testAddfield(self):
fld = OptionalField(UintField('field'))
s_init = [0, 'hi']
val = 10
s_final = fld.addfield(None, s_init, val)
self.assertEqual(s_final, [0, 'hi', 10])
s_init = [0, 'hi']
val = False
s_final = fld.addfield(None, s_init, val)
self.assertEqual(s_final, [0, 'hi', False])
s_init = [0, 'hi']
val = None
s_final = fld.addfield(None, s_init, val)
self.assertEqual(s_final, [0, 'hi'])
def testGetfield(self):
fld = OptionalField(UintField('field'))
s_init = [10, 0, 'hi']
(s_final, val) = fld.getfield(None, s_init)
self.assertEqual(s_final, [0, 'hi'])
self.assertEqual(val, 10)
s_init = [None]
(s_final, val) = fld.getfield(None, s_init)
self.assertEqual(s_final, [])
self.assertEqual(val, None)
s_init = []
(s_final, val) = fld.getfield(None, s_init)
self.assertEqual(s_final, [])
self.assertEqual(val, None)
def testDecode(self):
fld = OptionalField(UintField('field'))
self.assertEqual(fld.m2i(None, 10), 10)
self.assertEqual(fld.m2i(None, False), 0)
def testDecode(self):
fld = FieldListField('field', [], UintField('field'))
self.assertEqual(fld.m2i(None, [0]), [0])
self.assertEqual(fld.m2i(None, [1, 2]), [1, 2])
class BundleAgeBlock(CborItem):
''' Block data from BPbis Section 4.3.2.
'''
fields_desc = (
UintField('age'),
)
class CanonicalBlock(AbstractBlock):
''' The canonical block definition with a type-specific payload.
Any payload of this block is encoded as the "data" field when building
and decoded from the "data" field when dissecting.
'''
@enum.unique
class Flag(enum.IntFlag):
''' Block flags.
Flags must be in LSbit-first order.
'''
NONE = 0
#: block must be removed from bundle if it can't be processed.
REMOVE_IF_NO_PROCESS = 0x10
#: bundle must be deleted if block can't be processed.
DELETE_IF_NO_PROCESS = 0x04
#: transmission of a status report is requested if block can't be processed.
STATUS_IF_NO_PROCESS = 0x02
#: block must be replicated in every fragment.
REPLICATE_IN_FRAGMENT = 0x01
fields_desc = (
UintField('type_code', default=None),
UintField('block_num', default=None),
FlagsField('block_flags', default=Flag.NONE, flags=Flag),
EnumField('crc_type', default=AbstractBlock.CrcType.NONE, enum=AbstractBlock.CrcType),
BstrField('btsd', default=None), # block-type-specific data here
ConditionalField(
BstrField('crc_value'),
lambda block: block.crc_type != 0
),
)
def ensure_block_type_specific_data(self):
''' Embed payload as field data if not already present.
'''
if isinstance(self.payload, scapy.packet.NoPayload):
return
if self.fields.get('btsd') is not None:
return
if isinstance(self.payload, AbstractCborStruct):
pay_data = bytes(self.payload)
else:
pay_data = self.payload.do_build()
self.fields['btsd'] = pay_data
def fill_fields(self):
self.ensure_block_type_specific_data()
super().fill_fields()
def self_build(self, *args, **kwargs):
self.ensure_block_type_specific_data()
return super().self_build(*args, **kwargs)
def do_build_payload(self):
# Payload is handled by self_build()
return b''
def post_dissect(self, s):
# Extract payload from fields
pay_type = self.fields.get('type_code')
pay_data = self.fields.get('btsd')
if (pay_data is not None and pay_type is not None):
try:
cls = self.guess_payload_class(None)
LOGGER.debug('CanonicalBlock.post_dissect with class %s from: %s', cls, encode_diagnostic(pay_data))
except KeyError:
cls = None
if cls is not None:
try:
pay = cls(pay_data)
self.add_payload(pay)
except Exception as err:
if conf.debug_dissector:
raise
LOGGER.warning('CanonicalBlock failed to dissect payload: %s', err)
return super().post_dissect(s)
def default_payload_class(self, payload):
return scapy.packet.Raw
@classmethod
def bind_type(cls, type_code):
''' Bind a block-type-specific packet-class handler.
:param int type_code: The type to bind to the payload class.
'''
def func(othercls):
scapy.packet.bind_layers(cls, othercls, type_code=type_code)
return othercls
return func
