[JarryShaw]

• Searched for similar pull requests
• Followed the coding style
• make test passes, and a test case covers the change
• Changelog entry: N/A — centralised in docs(changelog): shared 1.5.0 changelog — long-lived, merges last (#610, #616, #617, #618, #620) #657

What is the purpose of your pull request?

• docs — documentation only

---

Description

Part of #1103, round 7. A full read of pcapkit/protocols/link, transport and their models. Prose only: the AST guard is identical on all 7 .py files.

• L2TP: the tunnel ID is the Session ID's lower half, and L2TPv2.read documents its version check.
• ARP/Ethernet: make Raises name what the address makers raise (fix(ethernet,pcapng): reject a non-string MAC or EUI address (#2222) #2232, fix(arp): prefix the hardware-address messages and reject a bool with ProtocolError (#2256) #2257).
• SCTP:
  • The final-chunk padding clamp is for captures (RFC 9260 §3.2 says MUST pad).
  • INIT/HEARTBEAT/ABORT/ERROR fold their padding.
  • The SACK a_rwnd minimum applies to INIT only.
  • PPID member names are corrected.
• TCP: Flags has its own _missing_; FieldValueError added to the MPTCP Raises.
• Tests: tests/protocols/link 113 passed, tests/protocols/transport 245; docs and docstring-contract tests pass.

[JarryShaw]

Review: GOOD TO GO at 6dfb55d81 (Sonnet).

• Prose only: the AST guard with docstrings stripped is identical on all 7 .py files.
• Claims: each claim checked against the code or RFC holds:
  • L2TPv2's tunnel ID is the Session ID's lower half (run: 00025678… gives tunnelid=0x5678), and the version check raises ProtocolError;
  • the ARP.make and Ethernet.make Raises match runs of True, 5 and 'zz';
  • RFC 9260 §3.2 says MUST pad, and exactly six chunk schemas fold their padding;
  • the PPID 60/66 member names;
  • Flags._missing_ accepts 0–0xFFFF;
  • _make_mptcp_addaddr(addr=True) raises FieldValueError.
• Tests: link, transport, docstring-contract, docs and convention tests give 475 passed. No text pins.
• Follow-ups:
  • ngap.rst repeats the short PPID names; that goes with docs(protocols): seventh whole-repo pass over application, misc and the protocol bases (#1103) #2262.
  • The L2TP test docstring is in the tests PR.

[github-actions]

Coverage: 91.56% (unit tier, Python 3.15, 6dfb55d81, Unit Tests run success)

Package	Statements	Missed	Branches	Partial	Cover
pcapkit (top level)	104	4	20	2	95.16%
pcapkit/const	19599	881	2618	867	92.11%
pcapkit/corekit	2589	74	816	37	96.51%
pcapkit/dumpkit	282	3	102	3	98.44%
pcapkit/foundation	3023	23	1044	25	98.82%
pcapkit/interface	138	4	52	3	96.32%
pcapkit/protocols	17437	218	4586	185	98.15%
pcapkit/toolkit	869	36	298	10	95.20%
pcapkit/utilities	504	7	146	5	98.15%
pcapkit/vendor	4432	1988	1018	167	51.87%

Per-file detail: the coverage-html artifact of this run.

[JarryShaw]

Ready to merge at 6dfb55d81. Part of #1103, round 7: link and transport.

• Review: Sonnet GOOD TO GO.
• CI: all checks complete, Required checks passed SUCCESS, 0 failed. Sync Status is board sync, not CI.
• KTLO: 12 legs, no warnings (the 3.9 leg re-run after an artifact-upload ECONNRESET).
• Ordering: merged into main and run. protocols leg: 1942 tests, 0 failures.
• Conflicts: none against the current main (5fd197fad, whose vendor-doc commit touches no file in this PR).