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fix(ipv6-opts): RPL option drops reserved flag bits on rebuild and rejects RFC 6553 sub-TLVs #1201

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Merged
JarryShaw merged 1 commit into from
Oct 7, 2026
Merged

fix(ipv6-opts): RPL option drops reserved flag bits on rebuild and rejects RFC 6553 sub-TLVs #1201

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8 changes: 6 additions & 2 deletions pcapkit/protocols/data/internet/hopopt.py
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Original file line number Diff line number Diff line change
Expand Up @@ -226,9 +226,11 @@ class RPLFlags(Data):
rank_err: 'bool'
#: Forwarding error flag.
fwd_err: 'bool'
#: Reserved flag bits, carried verbatim so that a rebuild reproduces them.
reserved: 'int'

if TYPE_CHECKING:
def __init__(self, down: 'bool', rank_err: 'bool', fwd_err: 'bool') -> 'None': ... # pylint: disable=super-init-not-called,unused-argument,redefined-builtin,multiple-statements,line-too-long
def __init__(self, down: 'bool', rank_err: 'bool', fwd_err: 'bool', reserved: 'int') -> 'None': ... # pylint: disable=super-init-not-called,unused-argument,redefined-builtin,multiple-statements,line-too-long


@info_final
Expand All @@ -241,9 +243,11 @@ class RPLOption(Option):
id: 'int'
#: Sender rank.
rank: 'int'
#: Sub-TLVs [:rfc:`6553#section-3`], kept as raw octets.
sub_tlvs: 'bytes'

if TYPE_CHECKING:
def __init__(self, type: 'Enum_Option', action: 'int', change: 'bool', length: 'int', flags: 'RPLFlags', id: 'int', rank: 'int') -> 'None': ... # pylint: disable=super-init-not-called,unused-argument,redefined-builtin,multiple-statements,line-too-long
def __init__(self, type: 'Enum_Option', action: 'int', change: 'bool', length: 'int', flags: 'RPLFlags', id: 'int', rank: 'int', sub_tlvs: 'bytes') -> 'None': ... # pylint: disable=super-init-not-called,unused-argument,redefined-builtin,multiple-statements,line-too-long


@info_final
Expand Down
8 changes: 6 additions & 2 deletions pcapkit/protocols/data/internet/ipv6_opts.py
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Original file line number Diff line number Diff line change
Expand Up @@ -236,10 +236,12 @@ class RPLFlags(Data):
rank_err: 'bool'
#: Forwarding error flag.
fwd_err: 'bool'
#: Reserved flag bits, carried verbatim so that a rebuild reproduces them.
reserved: 'int'

if TYPE_CHECKING:
def __init__(self, down: 'bool', rank_err: 'bool',
fwd_err: 'bool') -> 'None': ... # pylint: disable=super-init-not-called,unused-argument,redefined-builtin,multiple-statements,line-too-long
fwd_err: 'bool', reserved: 'int') -> 'None': ... # pylint: disable=super-init-not-called,unused-argument,redefined-builtin,multiple-statements,line-too-long


@info_final
Expand All @@ -252,10 +254,12 @@ class RPLOption(Option):
id: 'int'
#: Sender rank.
rank: 'int'
#: Sub-TLVs [:rfc:`6553#section-3`], kept as raw octets.
sub_tlvs: 'bytes'

if TYPE_CHECKING:
def __init__(self, type: 'Enum_Option', action: 'int', change: 'bool', length: 'int', flags: 'RPLFlags', id: 'int',
rank: 'int') -> 'None': ... # pylint: disable=super-init-not-called,unused-argument,redefined-builtin,multiple-statements,line-too-long
rank: 'int', sub_tlvs: 'bytes') -> 'None': ... # pylint: disable=super-init-not-called,unused-argument,redefined-builtin,multiple-statements,line-too-long


@info_final
Expand Down
28 changes: 25 additions & 3 deletions pcapkit/protocols/internet/hopopt.py
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Original file line number Diff line number Diff line change
Expand Up @@ -992,6 +992,9 @@ def _read_opt_rpl(self, schema: 'Schema_RPLOption', *, options: 'Option') -> 'Da
| (sub-TLVs) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

The sub-TLVs, which :rfc:`6553#section-3` says MUST be skipped when
unrecognised, are kept as raw octets in ``sub_tlvs``.

Args:
schema: parsed parameter schema
options: extracted HOPOPT options
Expand All @@ -1000,10 +1003,10 @@ def _read_opt_rpl(self, schema: 'Schema_RPLOption', *, options: 'Option') -> 'Da
Parsed option data.

Raises:
ProtocolError: If ``schema.len`` is **NOT** ``4``.
ProtocolError: If ``schema.len`` is less than ``4``.

"""
if schema.len != 4:
if schema.len < 4:
raise ProtocolError(f'{self.alias}: [OptNo {schema.type}] invalid format')

opt = Data_RPLOption(
Expand All @@ -1015,9 +1018,11 @@ def _read_opt_rpl(self, schema: 'Schema_RPLOption', *, options: 'Option') -> 'Da
down=bool(schema.flags['down']),
rank_err=bool(schema.flags['rank_err']),
fwd_err=bool(schema.flags['fwd_err']),
reserved=schema.flags['reserved'],
),
id=schema.id,
rank=schema.rank,
sub_tlvs=schema.sub_tlvs,
)
return opt

Expand Down Expand Up @@ -1815,6 +1820,8 @@ def _make_opt_rpl(self, code: 'Enum_Option', opt: 'Optional[Data_RPLOption]' = N
fwd_err: 'bool' = False,
id: 'int' = 0,
rank: 'int' = 0,
reserved: 'int' = 0,
sub_tlvs: 'bytes' = b'',
**kwargs: 'Any') -> 'Schema_RPLOption':
"""Make HOPOPT RPL option.

Expand All @@ -1826,29 +1833,44 @@ def _make_opt_rpl(self, code: 'Enum_Option', opt: 'Optional[Data_RPLOption]' = N
fwd_err: forwarding error flag
id: RPL instance ID
rank: sender rank
reserved: reserved flag bits, i.e. the low five bits of the flags octet
sub_tlvs: sub-TLVs, as raw octets
**kwargs: arbitrary keyword arguments

Returns:
Constructed option schema.

Raises:
ProtocolError: If ``reserved`` does not fit in five bits, or
``sub_tlvs`` does not fit in the option.

"""
if opt is not None:
down = opt.flags.down
rank_err = opt.flags.rank_err
fwd_err = opt.flags.fwd_err
reserved = opt.flags.reserved
id = opt.id
rank = opt.rank
sub_tlvs = opt.sub_tlvs

if not 0 <= reserved < 32:
raise ProtocolError(f'{self.alias}: [OptNo {code}] invalid RPL reserved flags: {reserved}')
if len(sub_tlvs) > 251:
raise ProtocolError(f'{self.alias}: [OptNo {code}] too long RPL sub-TLVs: {len(sub_tlvs)}')

return Schema_RPLOption(
type=code,
len=4,
len=4 + len(sub_tlvs),
flags={
'down': down,
'rank_err': rank_err,
'fwd_err': fwd_err,
'reserved': reserved,
},
id=id,
rank=rank,
sub_tlvs=sub_tlvs,
)

def _make_opt_mpl(self, code: 'Enum_Option', opt: 'Optional[Data_MPLOption]' = None, *,
Expand Down
28 changes: 25 additions & 3 deletions pcapkit/protocols/internet/ipv6_opts.py
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Original file line number Diff line number Diff line change
Expand Up @@ -981,6 +981,9 @@ def _read_opt_rpl(self, schema: 'Schema_RPLOption', *, options: 'Option') -> 'Da
| (sub-TLVs) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

The sub-TLVs, which :rfc:`6553#section-3` says MUST be skipped when
unrecognised, are kept as raw octets in ``sub_tlvs``.

Args:
schema: parsed parameter schema
options: extracted IPv6-Opts options
Expand All @@ -989,10 +992,10 @@ def _read_opt_rpl(self, schema: 'Schema_RPLOption', *, options: 'Option') -> 'Da
Parsed option data.

Raises:
ProtocolError: If ``schema.len`` is **NOT** ``4``.
ProtocolError: If ``schema.len`` is less than ``4``.

"""
if schema.len != 4:
if schema.len < 4:
raise ProtocolError(f'{self.alias}: [OptNo {schema.type}] invalid format')

opt = Data_RPLOption(
Expand All @@ -1004,9 +1007,11 @@ def _read_opt_rpl(self, schema: 'Schema_RPLOption', *, options: 'Option') -> 'Da
down=bool(schema.flags['down']),
rank_err=bool(schema.flags['rank_err']),
fwd_err=bool(schema.flags['fwd_err']),
reserved=schema.flags['reserved'],
),
id=schema.id,
rank=schema.rank,
sub_tlvs=schema.sub_tlvs,
)
return opt

Expand Down Expand Up @@ -1804,6 +1809,8 @@ def _make_opt_rpl(self, code: 'Enum_Option', opt: 'Optional[Data_RPLOption]' = N
fwd_err: 'bool' = False,
id: 'int' = 0,
rank: 'int' = 0,
reserved: 'int' = 0,
sub_tlvs: 'bytes' = b'',
**kwargs: 'Any') -> 'Schema_RPLOption':
"""Make IPv6-Opts RPL option.

Expand All @@ -1815,29 +1822,44 @@ def _make_opt_rpl(self, code: 'Enum_Option', opt: 'Optional[Data_RPLOption]' = N
fwd_err: forwarding error flag
id: RPL instance ID
rank: sender rank
reserved: reserved flag bits, i.e. the low five bits of the flags octet
sub_tlvs: sub-TLVs, as raw octets
**kwargs: arbitrary keyword arguments

Returns:
Constructed option schema.

Raises:
ProtocolError: If ``reserved`` does not fit in five bits, or
``sub_tlvs`` does not fit in the option.

"""
if opt is not None:
down = opt.flags.down
rank_err = opt.flags.rank_err
fwd_err = opt.flags.fwd_err
reserved = opt.flags.reserved
id = opt.id
rank = opt.rank
sub_tlvs = opt.sub_tlvs

if not 0 <= reserved < 32:
raise ProtocolError(f'{self.alias}: [OptNo {code}] invalid RPL reserved flags: {reserved}')
if len(sub_tlvs) > 251:
raise ProtocolError(f'{self.alias}: [OptNo {code}] too long RPL sub-TLVs: {len(sub_tlvs)}')

return Schema_RPLOption(
type=code,
len=4,
len=4 + len(sub_tlvs),
flags={
'down': down,
'rank_err': rank_err,
'fwd_err': fwd_err,
'reserved': reserved,
},
id=id,
rank=rank,
sub_tlvs=sub_tlvs,
)

def _make_opt_mpl(self, code: 'Enum_Option', opt: 'Optional[Data_MPLOption]' = None, *,
Expand Down
22 changes: 21 additions & 1 deletion pcapkit/protocols/schema/internet/hopopt.py
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Original file line number Diff line number Diff line change
Expand Up @@ -73,6 +73,8 @@ class RPLFlags(TypedDict):
rank_err: int
#: Forwarding error flag.
fwd_err: int
#: Reserved flag bits.
reserved: int

class MPLFlags(TypedDict):
"""MPL flags."""
Expand Down Expand Up @@ -119,6 +121,21 @@ class QSNonce(TypedDict):
nonce: int


def rpl_opt_sub_tlv_len(pkt: 'dict[str, Any]') -> 'int':
"""Return RPL option sub-TLV length.

Args:
pkt: RPL option unpacked schema.

Returns:
RPL option sub-TLV length, i.e. ``Opt Data Len`` less the four octets
of the fixed fields. An ``Opt Data Len`` below ``4`` gives ``0``, and
the reader then rejects the option.

"""
return max(pkt['len'] - 4, 0)


def mpl_opt_seed_id_len(pkt: 'dict[str, Any]') -> 'int':
"""Return MPL Seed-ID length.

Expand Down Expand Up @@ -667,15 +684,18 @@ class RPLOption(Option, code=[Enum_Option.RPL_Option_0x23,
'down': (0, 1),
'rank_err': (1, 1),
'fwd_err': (2, 1),
'reserved': (3, 5),
})
#: RPL instance ID.
id: 'int' = UInt8Field()
#: Sender rank.
rank: 'int' = UInt16Field()
#: Sub-TLVs, kept as raw octets.
sub_tlvs: 'bytes' = BytesField(length=rpl_opt_sub_tlv_len)

if TYPE_CHECKING:
def __init__(self, type: 'Enum_Option', len: 'int', flags: 'RPLFlags', id: 'int',
rank: 'int') -> 'None': ...
rank: 'int', sub_tlvs: 'bytes') -> 'None': ...


@schema_final
Expand Down
22 changes: 21 additions & 1 deletion pcapkit/protocols/schema/internet/ipv6_opts.py
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Original file line number Diff line number Diff line change
Expand Up @@ -73,6 +73,8 @@ class RPLFlags(TypedDict):
rank_err: int
#: Forwarding error flag.
fwd_err: int
#: Reserved flag bits.
reserved: int

class MPLFlags(TypedDict):
"""MPL flags."""
Expand Down Expand Up @@ -119,6 +121,21 @@ class QSNonce(TypedDict):
nonce: int


def rpl_opt_sub_tlv_len(pkt: 'dict[str, Any]') -> 'int':
"""Return RPL option sub-TLV length.

Args:
pkt: RPL option unpacked schema.

Returns:
RPL option sub-TLV length, i.e. ``Opt Data Len`` less the four octets
of the fixed fields. An ``Opt Data Len`` below ``4`` gives ``0``, and
the reader then rejects the option.

"""
return max(pkt['len'] - 4, 0)


def mpl_opt_seed_id_len(pkt: 'dict[str, Any]') -> 'int':
"""Return MPL Seed-ID length.

Expand Down Expand Up @@ -672,15 +689,18 @@ class RPLOption(Option, code=[Enum_Option.RPL_Option_0x23,
'down': (0, 1),
'rank_err': (1, 1),
'fwd_err': (2, 1),
'reserved': (3, 5),
})
#: RPL instance ID.
id: 'int' = UInt8Field()
#: Sender rank.
rank: 'int' = UInt16Field()
#: Sub-TLVs, kept as raw octets.
sub_tlvs: 'bytes' = BytesField(length=rpl_opt_sub_tlv_len)

if TYPE_CHECKING:
def __init__(self, type: 'Enum_Option', len: 'int', flags: 'RPLFlags', id: 'int',
rank: 'int') -> 'None': ...
rank: 'int', sub_tlvs: 'bytes') -> 'None': ...


@schema_final
Expand Down
9 changes: 5 additions & 4 deletions tests/protocols/internet/test_ipv6_extension_unit.py
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Original file line number Diff line number Diff line change
Expand Up @@ -854,8 +854,9 @@ def _assert_option_data_model_constructor_edges(self, protocol_cls: type) -> Non
rpl = proto._make_opt_rpl(
Option.RPL_Option_0x63,
data.RPLOption(type=Option.RPL_Option_0x63, length=6,
flags=data.RPLFlags(down=True, rank_err=True, fwd_err=False),
id=5, rank=6, **base),
flags=data.RPLFlags(down=True, rank_err=True, fwd_err=False,
reserved=0),
id=5, rank=6, sub_tlvs=b'', **base),
)
self.assertTrue(rpl.flags['down'])
mpl = proto._make_opt_mpl(
Expand Down Expand Up @@ -1222,8 +1223,8 @@ def assert_bad(reader, option_schema) -> None:

rpl = proto._read_opt_rpl(
schema.RPLOption(type=Option.RPL_Option_0x63, len=4,
flags={'down': 1, 'rank_err': 0, 'fwd_err': 1},
id=9, rank=10),
flags={'down': 1, 'rank_err': 0, 'fwd_err': 1, 'reserved': 0},
id=9, rank=10, sub_tlvs=b''),
options=options,
)
self.assertTrue(rpl.flags.down)
Expand Down
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