feat(internet): implement ICMP and ICMPv6, sharing a thin dispatch base

Closes #2436. ICMP (RFC 792) and ICMPv6 (RFC 4443) had no implementation at
all -- Internet.__proto__ had no entry for either protocol number, so a
packet carrying one fell back to Raw with only the protocol number as a
hint.

- Add ICMP_Family between Internet and ICMP/ICMPv6, following the IP/IPsec
  precedent: nothing but id(). The base's own name is "_Family"-suffixed
  (matching IPv6_Route, IPv6_Ext) because, unlike IP/IPsec, the family's
  generic name collides with one of its own members (ICMP).
- ICMP: Echo/Echo Reply, Destination Unreachable, Time Exceeded, Parameter
  Problem, plus a raw fallback for any other type. Own type registry
  (__type__, register_type), own schema. Both classes construct with no
  arguments (default body is the minimum valid length) and compute/verify
  their own checksum via a new shared pcapkit.utilities.checksum.inet_checksum
  (RFC 1071): ICMP sums the message alone, ICMPv6 additionally sums the IPv6
  pseudo-header (RFC 2460 Section 8.1) when the enclosing IPv6 addresses are
  known; a bad checksum warns rather than raises.
- ICMPv6: Destination Unreachable, Packet Too Big, Time Exceeded, Parameter
  Problem, Echo Request/Reply, plus the same raw fallback. Neighbor Discovery
  (RFC 4861) and MLD (RFC 9777, which obsoletes RFC 3810) are explicitly out
  of scope and not yet tracked by an issue of their own.
- New const/vendor registries: icmp.type and its three code registries, and
  the icmpv6 counterparts, as real IANA CSV crawlers (not hand-typed data),
  so a vendor-cron run picks up registry changes the way every other
  protocol's constants do.
- Wire ICMP/IPv6_ICMP into Internet.__proto__, and delete the two 0-byte
  NotImplemented stubs.
- docs/source/contributing/pep.rst: correct the ICMP/ICMPv6 follow-up prose
  (MLD's RFC citation, the Neighbor Discovery/NDP cross-reference, and a
  stale "wave 2 deliverable" claim about MLD elsewhere in the same file).
- Update every registry-shape test the new entries touch: the const enum
  sweep-size pins, the dispatch registry's case count and PINNED_TARGETS,
  the package re-export and public-API surface checks, the vendor
  reachability and missing-body sweeps, and the handful of runtime/
  integration tests whose protochain string literally said "IPv6_ICMP"
  where it now says "ICMPv6". Also moved an unrelated test fixture off
  IGMP's protocol number, which #2439 is about to register.
- Cross-review round: checksum verification used to warn on genuinely valid
  traffic -- a first IP/IPv6 fragment, a short-snaplen capture, and an IPv6
  Routing Header with Segments Left set -- by summing a slice of the message
  against a checksum computed over the whole thing; all three now skip
  verification instead of warning. ICMPv6 reached over IPv4 (protocol 58)
  used to crash the layer to Raw (IPv4Address fed to IPv6Address); it now
  skips verification the same way. inet_checksum's end-around-carry fold was
  hardcoded to two rounds, wrong for inputs around 131078+ octets; it now
  loops until no carry remains, per RFC 1071. Three docstrings claiming the
  checksum is never verified/computed are corrected, and icmpv6.py's MLD
  citation is brought in line with pep.rst's own RFC 9777 correction.
- Cross-review round 3: a Mobile IPv6 node (RFC 6275 Section 11.3.1)
  checksums against its home address, not the wire-visible care-of address
  in ipv6.src; IPv6._decode_next_layer now threads the Destination Options
  Home Address option through __packet__['home_address'] for ICMPv6.read to
  use in its place. A malformed Routing header (wrong Hdr Ext Len) falls
  back to the generic IPv6_Ext parser, whose info has no seg_left key;
  info.get('seg_left', 0) silently read that as zero instead of "unknown",
  letting a non-zero Segments Left through unflagged. Segments Left is now
  read from the header's raw 4th octet whenever the structured parse did
  not leave it behind.
- Cross-review round 6: two more instances of the same root cause, each
  found by a payload that reaches ICMP/ICMPv6 through a path the earlier
  flags never covered. (A) IP reassembly's Deferred(self.protocol.analyze,
  ...) threaded no packet context at all, so a reasm_strict=False datagram
  -- a zero-filled hole or a truncated prefix -- reached ICMP/ICMPv6 looking
  exactly like a complete message, including through a tunnel (4-in-4,
  6-in-6) whose inner layer's own fresh parse has no way to know the outer
  datagram might be incomplete. (B) A malformed sibling option (e.g. a
  wrong-length Tunnel Encapsulation Limit) knocks IPv6_Opts into its generic
  IPv6_Ext fallback, whose info carries no options at all, silently losing a
  genuine Home Address option the same way round 3's Routing header bug
  lost Segments Left.

  Rather than add a sixth ad-hoc __packet__ key, the five this grew across
  five rounds (mf, route_seg_left, home_address, and two unnamed checks) are
  replaced by one ChecksumContext (pcapkit/protocols/internet/icmp_family.py):
  `incomplete` (sticky across tunnel nesting -- a fragment or a reassembly
  dispatch), `misrouted` (scoped to one layer -- a Routing header; keeping
  it separate from `incomplete` is what a regression caught mid-round --
  conflating the two let an outer Routing header silence a genuinely corrupt
  inner checksum), and `src`/`dst` (never inherited by a nested layer, and
  may name ADDRESS_UNKNOWN when an address override was due but could not
  be recovered, as opposed to "no override is due"). ICMP and ICMPv6 now
  call the same verifiable_for_icmp()/verifiable_for_icmpv6() rather than
  reading ad-hoc flags apiece; fail-closed by construction and documented in
  one docstring instead of five scattered ones.

  Deferred gained an optional packet= parameter, purely additive (every
  existing call site omits it and sees no change) and still picklable under
  every protocol (#2423/#2425/#2435), so IP.submit can seed every reassembly
  dispatch already `incomplete`, unconditionally: that second parse never
  verifies a checksum of its own, complete datagram or not, since whichever
  fragments needed checking were already checked, with real context, on
  their own first pass through the frame. IPv6._home_address recovers a
  Destination Options Home Address by walking the raw option TLVs directly
  when the dedicated parser's fallback info has none -- the same move round
  3 made for a Routing header's Segments Left -- and reports ADDRESS_UNKNOWN
  rather than guessing "no Home Address here" when the walk cannot complete
  cleanly.

- Cross-review round 7: round 6's own ChecksumContext fix had three further
  gaps, plus one unrelated pickling regression it introduced.
  (A) Eight extension-header parsers (AH, IPv6_Opts, IPv6_Route, HOPOPT,
  IPv6_Frag, MH, HIP, IPv6_Ext) dispatch to their own next layer with no
  packet= of their own whenever they are the outermost protocol rather than
  a header IPv6._decode_next_layer is itself walking, silently dropping
  ChecksumContext and leaving ICMP/ICMPv6 with a fresh, never-populated one
  -- reproduced by an AH-protected first IP fragment losing the fragment's
  own `incomplete` flag and warning on a checksum that only ever covered
  part of the message. Fixed structurally rather than at each of the eight
  sites: a new ambient `_checksum_context` contextvars.ContextVar (the same
  pattern `_frame_depth` already uses) is set by IPv4.read, IPv6.read and
  Deferred.__call__ around their own dispatch, and
  ChecksumContext.from_packet falls back to it whenever __packet__ carries
  no context of its own -- so any intervening layer, these eight or one
  written later with no knowledge of this feature at all, is covered
  without a fix of its own.
  (B) IP.submit seeded every reassembly dispatch's ChecksumContext as
  unconditionally `incomplete`, which went too far: a genuinely corrupt
  checksum spread across multiple fragments became unreachable everywhere,
  never checked on any non-first fragment's own pass (there isn't one) and
  no longer checked on the reassembled pass either, complete or not. It is
  now `incomplete` only while reassembly itself is still incomplete, or
  when at most one fragment contributed (already checked on its own direct
  first pass) -- a multi-fragment datagram that reassembled in whole is
  finally verified, on the only pass that was ever going to see the whole
  thing.
  (C) IPv6._home_address's raw-byte-scan fallback treated a Home Address
  option of any length other than 16 the same as no option at all, letting
  ICMPv6 verify against the wire source as if Mobile IPv6 were not in
  play; a present-but-wrong-length option now reports ADDRESS_UNKNOWN, same
  as the framing breaks it already handled.
  (D) Deferred.__call__ read self.packet directly, so a Deferred pickled
  before round 6's packet= parameter existed raised AttributeError on
  call despite that parameter's "purely additive" versionchanged note; it
  now reads packet through getattr with a None default.

- Cross-review round 10: round 9 confirmed the design closes every
  reachable path; mutation testing found Deferred.__call__'s own
  _checksum_context.set() -- unlike the equivalent set() in IPv4.read and
  IPv6.read -- had no regression test. Pinned with a new extract()-driven
  case: AH riding directly on IPv4 (no IPv6) wrapping a corrupt-checksum
  ICMP, reassembled as a single fragment -- the one reachable shape where
  AH's own _decode_next_layer drops packet= on its way to ICMP, making
  the Deferred's ambient-context seed the ICMP layer's only source of
  context. Confirmed to actually depend on the fix: temporarily removing
  the .set() call makes the new test catch the corrupt checksum twice
  instead of once.

Build: the round's own command -- coverage run -m pytest over the ICMP/
ICMPv6/checksum unit tests, tests/foundation/reassembly, tests/const,
tests/vendor and tests/integration -- passes clean (915 passed, 27918
subtests, zero "invalid checksum" warnings on genuinely valid traffic, and a
genuinely corrupt reassembled checksum now warns). The full
tests/protocols/internet (623 passed, 12530 subtests) and tests/foundation
(580 passed, 17 skipped, 1858 subtests) directories, covering every prior
round's own regression test by name, pass clean as well. Round 10's own
command -- coverage run -m pytest over tests/foundation/reassembly, the
ICMP/ICMPv6 roundtrip suites and the checksum unit tests -- passes clean
as well (244 passed, 910 subtests).

Author: JarryShaw

Pipfile

@@ -9,6 +9,7 @@ chardet = "*"
 dictdumper = ">=0.8.5"
 emoji = "*"
 tbtrim = "~=0.3.1"
+requests = "*"
 
 [dev-packages]
 pypcapkit = {editable = true,path = "."}

docs/source/contributing/conventions/sentinel-convention.rst

@@ -35,6 +35,9 @@ derives from it mechanically -- title-case each underscore-separated word and ap
    * - ``ABSENT``
      - :class:`~pcapkit.corekit.sentinels.AbsentType`
      - :mod:`pcapkit.corekit.sentinels`
+   * - ``ADDRESS_UNKNOWN``
+     - :class:`~pcapkit.corekit.sentinels.AddressUnknownType`
+     - :mod:`pcapkit.corekit.sentinels`
 
 GitHub issue :issue:`911`'s housing ruling -- one module for all of them -- is why the table
 names a single defining module, and it is the only import path. The modules that *use* a

docs/source/contributing/pep.rst

@@ -41,16 +41,27 @@ one. Grouped by each TCP/IP layer and ordered by protocol name alphabetically,
 the ones outstanding are,
 
 * Link Layer: DSL, EAPOL, FDDI, ISDN, LINUX_SLL, LINUX_SLL2, NDP, PPP
-* Internet Layer: ECN, ICMP, ICMPv6, IGMP, Shim6
+* Internet Layer: ECN, IGMP, Shim6
 * Transport Layer: DCCP, RSVP
 * Application Layer: BGP, DHCP, DHCPv6, DNS, DTLS, IMAP, LDAP, MQTT, NNTP,
   NTP, ONC/RPC, POP, QUIC, RIP, RTP, SIP, SMTP, SNMP, SSH, Telnet, TLS/SSL,
   XMPP
 
-Several of these come in pairs that want a shared abstract base rather than two
-independent implementations, in the way
-:class:`~pcapkit.protocols.internet.ip.IP` already covers its family: ICMP with
-ICMPv6, TLS/SSL with DTLS, and ``LINUX_SLL`` with ``LINUX_SLL2``.
+ICMP and ICMPv6 landed following the same shared-base pattern
+:class:`~pcapkit.protocols.internet.ip.IP` already set for IPv4/IPv6 and
+:class:`~pcapkit.protocols.internet.ipsec.IPsec` for AH/ESP (GitHub issue
+:issue:`2436`):
+:class:`~pcapkit.protocols.internet.icmp_family.ICMP_Family` between
+:class:`~pcapkit.protocols.internet.internet.Internet` and
+:class:`~pcapkit.protocols.internet.icmp.ICMP` /
+:class:`~pcapkit.protocols.internet.icmpv6.ICMPv6`. Neighbor Discovery
+(:rfc:`4861`) and Multicast Listener Discovery (:rfc:`9777`, which obsoletes
+:rfc:`3810`; :rfc:`2710` for MLDv1), both of which ride in ICMPv6, are not
+part of this issue. Neighbor Discovery is the ``NDP`` already listed under
+Link Layer above, with a stub waiting at
+``pcapkit/protocols/link/NotImplemented/ndp.py``; MLD has neither a stub nor
+an open issue of its own yet. TLS/SSL with DTLS and ``LINUX_SLL`` with
+``LINUX_SLL2`` still want the shared-base treatment.
 :class:`~pcapkit.protocols.link.vlan.VLAN` is the closer precedent for a pair
 whose *layout* is identical -- it holds the whole of the tag, and
 :class:`~pcapkit.protocols.link.c_tag.C_Tag` and
@@ -349,10 +360,10 @@ Follow-ups to the bindings above:
   port number. That depends on the proxy identifying the version positively
   instead of guessing, since a guess path is wrong on non-HTTP input.
 
-Beyond those, the gaps most likely to be met in a real capture are ICMP (1),
-ICMPv6 (58) and IGMP (2) on the internet layer, each of which has a stub;
-and ``LINUX_SLL`` and ``LINUX_SLL2`` at the link layer, which every
-``tcpdump -i any`` capture uses and which have no stub.
+Beyond those, with ICMP (1) and ICMPv6 (58) now implemented, the gap most
+likely to be met in a real capture is IGMP (2) on the internet layer, which
+still has a stub; and ``LINUX_SLL`` and ``LINUX_SLL2`` at the link layer,
+which every ``tcpdump -i any`` capture uses and which have no stub.
 
 PCAPNG Support
 --------------
@@ -1071,12 +1082,12 @@ post-wave-1 consistency sweep described under `Release Plan — 1.5.0 in Two
 Steps`_ above.
 
 **Wave 2 — the protocol pairs that want a shared abstract base**, per `More
-Protocols, More!!!`_ above: **ICMP with ICMPv6**, **TLS/SSL with DTLS**, and
-``LINUX_SLL`` with ``LINUX_SLL2``, plus **IGMP** on its own. These are grouped
-because the shared-base question is the design work and doing either half of a
-pair alone would answer it twice. ``LINUX_SLL`` matters out of proportion to its
-size: every ``tcpdump -i any`` capture uses it, and neither variant has even a
-stub.
+Protocols, More!!!`_ above: **ICMP with ICMPv6** (done, :issue:`2436`),
+**TLS/SSL with DTLS**, and ``LINUX_SLL`` with ``LINUX_SLL2``, plus **IGMP**
+on its own. These are grouped because the shared-base question is the design
+work and doing either half of a pair alone would answer it twice.
+``LINUX_SLL`` matters out of proportion to its size: every ``tcpdump -i any``
+capture uses it, and neither variant has even a stub.
 
 **Done ahead of wave 2 — handlers for the** ``DLT_NULL`` **and** ``DLT_RAW``
 **link types.** Both are genuine DLTs that a capture can legitimately be rooted
@@ -1104,8 +1115,11 @@ above, which describes the payloads in question and why a registry of their own
 is wanted instead of
 :meth:`~pcapkit.protocols.protocol.Protocol._decode_next_layer`. It is
 sequenced *after* wave 2 rather than by preference: the multicast options embed
-:rfc:`3810` MLD, which rides in **ICMPv6**, and :rfc:`3376` **IGMP** records —
-both wave 2 deliverables. Landing the registry first would give a dispatch table
+:rfc:`9777` MLD (which obsoletes :rfc:`3810`; :rfc:`2710` for MLDv1), which
+rides in **ICMPv6**, and :rfc:`3376` **IGMP** records. Only the IGMP side is a
+wave 2 deliverable -- MLD itself is a follow-up to ICMPv6 (see `More
+Protocols, More!!!`_ above), not part of wave 2's own scope. Landing the
+registry first would give a dispatch table
 with nothing but :class:`~pcapkit.protocols.misc.raw.Raw` to register. The
 counter-argument is real though, and worth weighing rather than dismissing: changing the
 parsed shape from :obj:`bytes` to :class:`~pcapkit.protocols.misc.raw.Raw` is the

docs/source/pcapkit/const/icmp.rst

@@ -0,0 +1,82 @@
+=====================================================================
+:class:`~pcapkit.protocols.internet.icmp.ICMP` Constant Enumerations
+=====================================================================
+
+.. module:: pcapkit.const.icmp
+
+This module contains all constant enumerations of
+:class:`~pcapkit.protocols.internet.icmp.ICMP` implementations. Available
+enumerations include:
+
+.. list-table::
+
+   * - :class:`ICMP_Type <pcapkit.const.icmp.type.Type>`
+     - ICMP Type Numbers [*]_
+   * - :class:`ICMP_DestinationUnreachableCode <pcapkit.const.icmp.destination_unreachable_code.DestinationUnreachableCode>`
+     - ICMP Destination Unreachable Codes [*]_
+   * - :class:`ICMP_TimeExceededCode <pcapkit.const.icmp.time_exceeded_code.TimeExceededCode>`
+     - ICMP Time Exceeded Codes [*]_
+   * - :class:`ICMP_ParameterProblemCode <pcapkit.const.icmp.parameter_problem_code.ParameterProblemCode>`
+     - ICMP Parameter Problem Codes [*]_
+
+ICMP Type Numbers
+=================
+
+.. module:: pcapkit.const.icmp.type
+
+This module contains the constant enumeration for **ICMP Type Numbers**,
+which is automatically generated from :class:`pcapkit.vendor.icmp.type.Type`.
+
+.. autoclass:: pcapkit.const.icmp.type.Type
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+ICMP Destination Unreachable Codes
+===================================
+
+.. module:: pcapkit.const.icmp.destination_unreachable_code
+
+This module contains the constant enumeration for **ICMP Destination
+Unreachable Codes**, which is automatically generated from
+:class:`pcapkit.vendor.icmp.destination_unreachable_code.DestinationUnreachableCode`.
+
+.. autoclass:: pcapkit.const.icmp.destination_unreachable_code.DestinationUnreachableCode
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+ICMP Time Exceeded Codes
+=========================
+
+.. module:: pcapkit.const.icmp.time_exceeded_code
+
+This module contains the constant enumeration for **ICMP Time Exceeded
+Codes**, which is automatically generated from
+:class:`pcapkit.vendor.icmp.time_exceeded_code.TimeExceededCode`.
+
+.. autoclass:: pcapkit.const.icmp.time_exceeded_code.TimeExceededCode
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+ICMP Parameter Problem Codes
+==============================
+
+.. module:: pcapkit.const.icmp.parameter_problem_code
+
+This module contains the constant enumeration for **ICMP Parameter Problem
+Codes**, which is automatically generated from
+:class:`pcapkit.vendor.icmp.parameter_problem_code.ParameterProblemCode`.
+
+.. autoclass:: pcapkit.const.icmp.parameter_problem_code.ParameterProblemCode
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+.. rubric:: Footnotes
+
+.. [*] https://www.iana.org/assignments/icmp-parameters/icmp-parameters.xhtml#icmp-parameters-types
+.. [*] https://www.iana.org/assignments/icmp-parameters/icmp-parameters.xhtml#icmp-parameters-codes
+.. [*] https://www.iana.org/assignments/icmp-parameters/icmp-parameters.xhtml#icmp-parameters-codes
+.. [*] https://www.iana.org/assignments/icmp-parameters/icmp-parameters.xhtml#icmp-parameters-codes

docs/source/pcapkit/const/icmpv6.rst

@@ -0,0 +1,82 @@
+=========================================================================
+:class:`~pcapkit.protocols.internet.icmpv6.ICMPv6` Constant Enumerations
+=========================================================================
+
+.. module:: pcapkit.const.icmpv6
+
+This module contains all constant enumerations of
+:class:`~pcapkit.protocols.internet.icmpv6.ICMPv6` implementations. Available
+enumerations include:
+
+.. list-table::
+
+   * - :class:`ICMPv6_Type <pcapkit.const.icmpv6.type.Type>`
+     - ICMPv6 Type Numbers [*]_
+   * - :class:`ICMPv6_DestinationUnreachableCode <pcapkit.const.icmpv6.destination_unreachable_code.DestinationUnreachableCode>`
+     - ICMPv6 Destination Unreachable Codes [*]_
+   * - :class:`ICMPv6_TimeExceededCode <pcapkit.const.icmpv6.time_exceeded_code.TimeExceededCode>`
+     - ICMPv6 Time Exceeded Codes [*]_
+   * - :class:`ICMPv6_ParameterProblemCode <pcapkit.const.icmpv6.parameter_problem_code.ParameterProblemCode>`
+     - ICMPv6 Parameter Problem Codes [*]_
+
+ICMPv6 Type Numbers
+====================
+
+.. module:: pcapkit.const.icmpv6.type
+
+This module contains the constant enumeration for **ICMPv6 Type Numbers**,
+which is automatically generated from :class:`pcapkit.vendor.icmpv6.type.Type`.
+
+.. autoclass:: pcapkit.const.icmpv6.type.Type
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+ICMPv6 Destination Unreachable Codes
+======================================
+
+.. module:: pcapkit.const.icmpv6.destination_unreachable_code
+
+This module contains the constant enumeration for **ICMPv6 Destination
+Unreachable Codes**, which is automatically generated from
+:class:`pcapkit.vendor.icmpv6.destination_unreachable_code.DestinationUnreachableCode`.
+
+.. autoclass:: pcapkit.const.icmpv6.destination_unreachable_code.DestinationUnreachableCode
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+ICMPv6 Time Exceeded Codes
+============================
+
+.. module:: pcapkit.const.icmpv6.time_exceeded_code
+
+This module contains the constant enumeration for **ICMPv6 Time Exceeded
+Codes**, which is automatically generated from
+:class:`pcapkit.vendor.icmpv6.time_exceeded_code.TimeExceededCode`.
+
+.. autoclass:: pcapkit.const.icmpv6.time_exceeded_code.TimeExceededCode
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+ICMPv6 Parameter Problem Codes
+================================
+
+.. module:: pcapkit.const.icmpv6.parameter_problem_code
+
+This module contains the constant enumeration for **ICMPv6 Parameter
+Problem Codes**, which is automatically generated from
+:class:`pcapkit.vendor.icmpv6.parameter_problem_code.ParameterProblemCode`.
+
+.. autoclass:: pcapkit.const.icmpv6.parameter_problem_code.ParameterProblemCode
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+.. rubric:: Footnotes
+
+.. [*] https://www.iana.org/assignments/icmpv6-parameters/icmpv6-parameters.xhtml#icmpv6-parameters-types
+.. [*] https://www.iana.org/assignments/icmpv6-parameters/icmpv6-parameters.xhtml#icmpv6-parameters-type-1
+.. [*] https://www.iana.org/assignments/icmpv6-parameters/icmpv6-parameters.xhtml#icmpv6-parameters-type-3
+.. [*] https://www.iana.org/assignments/icmpv6-parameters/icmpv6-parameters.xhtml#icmpv6-parameters-type-4

docs/source/pcapkit/const/index.rst

@@ -80,6 +80,8 @@ Internet Layer
 
    esp
    hip
+   icmp
+   icmpv6
    ipv4
    ipv6
    ipx

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

@@ -0,0 +1,124 @@
+ICMP - Internet Control Message Protocol
+===========================================
+
+.. module:: pcapkit.protocols.internet.icmp
+
+:mod:`pcapkit.protocols.internet.icmp` contains
+:class:`~pcapkit.protocols.internet.icmp.ICMP` only,
+which implements extractor for Internet Control
+Message Protocol (ICMP) [*]_, whose structure is
+described as below:
+
+======= ========= ======================= ===================================
+Octets      Bits        Name                    Description
+======= ========= ======================= ===================================
+  0           0   ``icmp.type``             Type
+  1           8   ``icmp.code``             Code
+  2          16   ``icmp.checksum``         Checksum
+  4          32   ``icmp.data``             Message Body
+======= ========= ======================= ===================================
+
+.. autoclass:: pcapkit.protocols.internet.icmp.ICMP
+   :no-members:
+   :show-inheritance:
+
+   .. autoproperty:: name
+   .. autoproperty:: alias
+   .. autoproperty:: length
+
+   .. automethod:: id
+   .. automethod:: register_type
+
+   .. automethod:: read
+   .. automethod:: make
+
+   .. automethod:: _make_data
+
+   .. automethod:: _read_data_type_none
+   .. automethod:: _read_data_type_echo
+   .. automethod:: _read_data_type_destination_unreachable
+   .. automethod:: _read_data_type_time_exceeded
+   .. automethod:: _read_data_type_parameter_problem
+
+   .. automethod:: _make_data_type_none
+   .. automethod:: _make_data_type_echo
+   .. automethod:: _make_data_type_destination_unreachable
+   .. automethod:: _make_data_type_time_exceeded
+   .. automethod:: _make_data_type_parameter_problem
+
+   .. autoattribute:: __type__
+      :no-value:
+
+   .. automethod:: __length_hint__
+   .. automethod:: __index__
+
+Header Schemas
+--------------
+
+.. module:: pcapkit.protocols.schema.internet.icmp
+
+.. autoclass:: pcapkit.protocols.schema.internet.icmp.ICMP
+   :members:
+   :show-inheritance:
+
+.. autoclass:: pcapkit.protocols.schema.internet.icmp.ICMPType
+   :members:
+   :show-inheritance:
+
+.. autoclass:: pcapkit.protocols.schema.internet.icmp.Unknown
+   :members:
+   :show-inheritance:
+
+.. autoclass:: pcapkit.protocols.schema.internet.icmp.Echo
+   :members:
+   :show-inheritance:
+
+.. autoclass:: pcapkit.protocols.schema.internet.icmp.DestinationUnreachable
+   :members:
+   :show-inheritance:
+
+.. autoclass:: pcapkit.protocols.schema.internet.icmp.TimeExceeded
+   :members:
+   :show-inheritance:
+
+.. autoclass:: pcapkit.protocols.schema.internet.icmp.ParameterProblem
+   :members:
+   :show-inheritance:
+
+Auxiliary Functions
+~~~~~~~~~~~~~~~~~~~~
+
+.. autofunction:: pcapkit.protocols.schema.internet.icmp.icmp_data_selector
+
+Data Models
+-----------
+
+.. module:: pcapkit.protocols.data.internet.icmp
+
+.. autoclass:: pcapkit.protocols.data.internet.icmp.ICMP
+   :members:
+   :show-inheritance:
+
+.. autoclass:: pcapkit.protocols.data.internet.icmp.Unknown
+   :members:
+   :show-inheritance:
+
+.. autoclass:: pcapkit.protocols.data.internet.icmp.Echo
+   :members:
+   :show-inheritance:
+
+.. autoclass:: pcapkit.protocols.data.internet.icmp.DestinationUnreachable
+   :members:
+   :show-inheritance:
+
+.. autoclass:: pcapkit.protocols.data.internet.icmp.TimeExceeded
+   :members:
+   :show-inheritance:
+
+.. autoclass:: pcapkit.protocols.data.internet.icmp.ParameterProblem
+   :members:
+   :show-inheritance:
+
+.. rubric:: Footnotes
+
+.. [*] https://en.wikipedia.org/wiki/Internet_Control_Message_Protocol