fix(internet)!: refuse or rebuild exactly an MH mobility option changed in one octet (#2684) (#2700)

- Option fields were read at their own widths whatever the length said, so a
  length they overran or fell short of read octets that were not the option's
  and rebuilt another. A mobility option, FID, ANI or LCMP sub-option, QoS
  attribute or CGA extension whose fields do not take its declared length is
  refused, and so is a target care-of address neither IPv4 nor IPv6, as BID's is.
- A CGA public key takes the long form of a DER length, and a CGA parameter
  whose fixed fields or key run past its option is refused in the schema.
- The IPv4 Address Acknowledgement, IPv4 Home Address Request and Reply, and
  Delegated MNP makers check a prefix length against its field width alone, so
  one past the address that the reader keeps no longer refuses to rebuild.
- The Service Selection and MN-ID NAI makers count the octets the identifier
  packs as, rather than its text re-encoded or its characters.
- The QoS option keeps the two reserved traffic-class bits as tc_reserved, a
  new required field of its data model, which a direct construction now has to
  pass: the breaking change.
- Adds a one-octet mutation sweep over every registered mobility option.

New tests fail on be83061 without the pcapkit/ change; MH and guard modules pass.

Author: JarryShaw

docs/source/pcapkit/protocols/internet/mh.rst

@@ -987,6 +987,7 @@ Auxiliary Functions
 .. autofunction:: pcapkit.protocols.schema.internet.mh.pad_opt_data_len
 .. autofunction:: pcapkit.protocols.schema.internet.mh.bid_address_selector
 .. autofunction:: pcapkit.protocols.schema.internet.mh.br_code_selector
+.. autofunction:: pcapkit.protocols.schema.internet.mh.cga_public_key_length
 .. autofunction:: pcapkit.protocols.schema.internet.mh.dmnp_prefix_selector
 .. autofunction:: pcapkit.protocols.schema.internet.mh.fb_code_selector
 .. autofunction:: pcapkit.protocols.schema.internet.mh.lma_address_selector

pcapkit/protocols/data/internet/mh.py

@@ -2168,13 +2168,22 @@ def __init__(self, type: 'Enum_QoSAttribute', length: 'int', reserved: 'bytes',
 
 @info_final
 class QualityOfServiceOption(Option):
-    """Data model for MH Quality-of-Service option."""
+    """Data model for MH Quality-of-Service option.
+
+    .. versionchanged:: 1.6.0
+
+       New required field ``tc_reserved`` (:issue:`2684`).
+
+    """
 
     #: Service request identifier.
     sr_id: 'int'
     #: Differentiated services code point, the significant 6 bits of the traffic
     #: class octet.
     dscp: 'int'
+    #: The 2 reserved bits of the traffic class octet, after the code point, as
+    #: captured [:rfc:`7222#section-4.1`].
+    tc_reserved: 'int'
     #: Operational code -- ``0`` response, ``1`` allocate, ``2`` de-allocate,
     #: ``3`` modify, ``4`` query, ``5`` negotiate.
     oc: 'int'
@@ -2185,7 +2194,7 @@ class QualityOfServiceOption(Option):
 
     if TYPE_CHECKING:
         def __init__(self, type: 'Enum_Option', length: 'int', sr_id: 'int', dscp: 'int',
-                     oc: 'int',
+                     tc_reserved: 'int', oc: 'int',
                      reserved: 'bytes', attributes: 'OrderedMultiDict[Enum_QoSAttribute, QoSAttribute]') -> 'None': ...