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feat(link): decode radiotap's optional fields #2576

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#2657
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feat(link): decode radiotap's optional fields#2576
#2657
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featPull requests that add a new capability (feat: subject prefix)
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PyPCAPKit v1.6

Description

@JarryShaw
JarryShaw
opened on Nov 1, 2026

Follow-up from #2502: Radiotap (#2509) records every present-flags word but keeps the optional fields it selects as raw fields. Decode them per the radiotap.org field specification: each field's alignment rule and size, the vendor namespace, and extended presence words. Keep unknown and vendor fields raw, with byte-exact round trips.

Blocked: #2575 also edits radiotap.py, its payload dispatch. This unblocks when #2575's PR merges.

Activity

  1. JarryShaw
    added
    featPull requests that add a new capability (feat: subject prefix)
    blockedDeferred pending another issue or decision; see the last comment for what unblocks it
    on Nov 1, 2026
  2. JarryShaw
    added this to PyPCAPKiton Nov 1, 2026
  3. JarryShaw
    moved this to Blocked in PyPCAPKiton Nov 1, 2026
  4. github-actions
    added this to the PyPCAPKit v1.6 milestone on Nov 2, 2026

  5. JarryShaw commented on Nov 2, 2026

    @JarryShaw
    JarryShaw
    on Nov 2, 2026
    OwnerAuthor

    #2607 has merged, so radiotap.py is free. Unblocked. A worker is on it. Optional fields are decoded per the radiotap.org specification and cross-checked against Wireshark or the kernel. Unknown and vendor fields stay raw, with byte-exact round trips.

  6. JarryShaw
    added
    wipWork in flight - a covering PR is open or an agent is actively on it
    and removed
    blockedDeferred pending another issue or decision; see the last comment for what unblocks it
    on Nov 2, 2026
  7. JarryShaw
    added a commit that references this issue on Nov 2, 2026

    docs(pep): correct stale status lines and drop the redundant release …

    83f05f5
  8. JarryShaw
    moved this from Blocked to WIP in PyPCAPKiton Nov 2, 2026

  9. JarryShaw commented on Nov 2, 2026

    @JarryShaw
    JarryShaw
    on Nov 2, 2026
    OwnerAuthor

    Optional-field decoding is done locally, and a Sonnet review is running.

    • Each defined field is decoded per radiotap.org, with its alignment counted from the header start. Extended presence words, the radiotap/vendor namespace switches and TLV mode are all handled.
    • Unknown and vendor fields stay raw. Captured octets round-trip exactly. Output for existing captures is unchanged.
    • The field types are a new pcapkit.const.radiotap.FieldType, generated by a crawler of radiotap.org.

    Needs deciding. The branch implements both recommendations unless you choose otherwise.

    1. Bits 16 and 17 (RTS retries, data retries). radiotap.org lists them only as unofficial, but Linux mac80211 writes bit 17 on TX-status frames. Decoding currently stops at them.
      • (a) Leave them undecoded.
      • (b) Decode both.
      • (c) Decode only bit 17, since OpenBSD writes RSSI in bit 16.
      • Recommend (c), as a follow-up.
    2. Bitmap fields stay plain integers. This covers Flags, the Channel flags, RX/TX flags and the MCS/VHT/HE known bits.
      • (a) Keep them as integers.
      • (b) Decode them into named flags. Each flag table then needs its own crawler.
      • Recommend (a). A follow-up could use the Flags FCS (0x10) and data-pad (0x20) bits to let IEEE802_11 split off the FCS and padding.
  10. JarryShaw
    added
    needs: decisionWaiting on the maintainer to decide — not blocked by other work
    on Nov 2, 2026

  11. JarryShaw commented on Nov 2, 2026

    @JarryShaw
    JarryShaw
    on Nov 2, 2026
    OwnerAuthor

    Take (b) on both questions

  12. JarryShaw commented on Nov 2, 2026

    @JarryShaw
    JarryShaw
    on Nov 2, 2026
    OwnerAuthor

    The owner chose (b) on both, paraphrased.

    1. Bits 16 and 17 are decoded. They are RTS retries and data retries, one octet each, and both are added to FieldType from radiotap.org's unofficial-fields table. The docstring notes that OpenBSD uses bit 16 differently.
    2. Bitmap fields decode into named flags rather than integers. This covers Flags, the Channel flags, RX/TX flags, and the MCS/VHT/HE/EHT/U-SIG known and flag bitmaps. Each flag table is a const registry with its own radiotap.org crawler. Undefined bits still round-trip.

    The branch is being reworked to match.

  13. JarryShaw
    removed
    needs: decisionWaiting on the maintainer to decide — not blocked by other work
    on Nov 2, 2026

  14. 3 remaining items

  15. JarryShaw commented on Nov 2, 2026

    @JarryShaw
    JarryShaw
    on Nov 2, 2026
    OwnerAuthor
    1. A for now. B is wanted
    2. Add them
    3. B
    4. Leaving it as is

  16. JarryShaw commented on Nov 2, 2026

    @JarryShaw
    JarryShaw
    on Nov 2, 2026
    OwnerAuthor

    The owner answered all four, paraphrased:

    1. Mixed bitmaps stay integers here. Splitting them into value subfields plus known-bit flags is wanted, and is filed as feat(link): split radiotap's mixed bitmaps into value subfields and known-bit flags #2647.
    2. The six other bit-by-bit bitmaps are added: A-MPDU flags, timestamp flags, L-SIG data1, S1G known, HE-MU-other-user per_user_known and VHT coding. Each gets a crawler.
    3. Member names get a name map in each crawler, using Linux's short names, as vendor/tcp/flags.py does.
    4. The "[Currently unspecified but used]" caption stays verbatim.

    This settles everything open here, so needs: decision comes off. The branch is being reworked for 2 and 3, then gets a cross-review before its PR opens.

  17. JarryShaw
    removed
    needs: decisionWaiting on the maintainer to decide — not blocked by other work
    on Nov 2, 2026
  18. JarryShaw
    moved this from Needs decision to WIP in PyPCAPKiton Nov 2, 2026

  19. JarryShaw commented on Nov 2, 2026

    @JarryShaw
    JarryShaw
    on Nov 2, 2026
    OwnerAuthor

    The PR is #2657.

  20. JarryShaw
    added 3 commits that reference this issue on Nov 2, 2026

    feat(link): decode radiotap's optional fields (#2576)

    2392363

    feat(link): decode radiotap's optional fields (#2576)

    53e71b4

    feat(link): decode radiotap's optional fields (#2576) (#2657)

    0c66303
  21. JarryShaw
    closed this as completedin #2657on Nov 2, 2026
  22. github-project-automation
    moved this from WIP to Done in PyPCAPKiton Nov 2, 2026
  23. JarryShaw
    removed
    wipWork in flight - a covering PR is open or an agent is actively on it
    on Nov 2, 2026
  24. JarryShaw
    added 4 commits that reference this issue on Nov 2, 2026

    feat(link): decode radiotap TLV items a producer cut short (#2655)

    c3fc0d3

    feat(link): decode radiotap TLV items a producer cut short (#2655) (#…

    342fe7e

    feat(link): split radiotap's mixed bitmaps into value subfields (#2647)

    ddf28f9

    feat(link): split radiotap's mixed bitmaps into value subfields (#2647)…

    6253a87
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