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automotive, j1939: scanning for CAs - #5164

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BenGardiner wants to merge 5 commits into
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BenGardiner:j1939-soft-sockets-again
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BenGardiner wants to merge 5 commits into
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BenGardiner:j1939-soft-sockets-again

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@BenGardiner

@BenGardiner BenGardiner commented Sep 10, 2026 •

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Description

This adds j1939 scanning for Controller Applications on-top-of the soft socket support.

The changes aim to introduce only those J1939 value enumeration definitions which can be sourced from freely available locations on the internet. As such, there is not a complete list of the values.

I don't intend any impacts on other parts of the libraries.

fixes missing sr1() functionality in J1939 soft socket on master

LLM coding tools were used in the development of this PR: copilot and gemini, various models.

@BenGardiner

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@polybassa

Comment thread scapy/contrib/automotive/j1939/__init__.py Outdated
Comment thread scapy/contrib/automotive/j1939/__init__.py Outdated
Comment thread scapy/contrib/automotive/j1939/j1939_dm.py Outdated
Comment thread scapy/contrib/automotive/j1939/j1939_dm.py Outdated
Comment thread scapy/contrib/automotive/j1939/j1939_dm.py Outdated
Comment thread scapy/contrib/automotive/j1939/j1939_dm.py Outdated
Comment thread scapy/contrib/automotive/j1939/j1939_dm.py Outdated
Comment thread scapy/contrib/automotive/j1939/j1939_dm.py Outdated
Comment thread scapy/contrib/automotive/j1939/j1939_dm.py Outdated
Comment thread scapy/contrib/automotive/j1939/j1939_dm.py Outdated
Comment thread scapy/contrib/automotive/j1939/j1939_dm.py Outdated
Comment thread scapy/contrib/automotive/j1939/j1939_dm_scanner.py Outdated
Comment thread scapy/contrib/automotive/j1939/j1939_name.py Outdated
Comment thread scapy/contrib/automotive/j1939/j1939_name.py Outdated
Comment thread scapy/contrib/automotive/j1939/j1939_scanner.py
Comment thread scapy/contrib/automotive/j1939/j1939_scanner.py Outdated
Comment thread scapy/contrib/automotive/j1939/j1939_scanner.py Outdated
Comment thread scapy/contrib/automotive/j1939/j1939_scanner.py Outdated
Comment thread scapy/contrib/automotive/j1939/j1939_scanner.py Outdated
Comment thread scapy/contrib/automotive/j1939/j1939_scanner.py Outdated
@BenGardiner

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thanks @polybassa for the review. I can do almost all of that right now. There's a couple things that are either answering your questions or require me to ask you questions first.

@BenGardiner
BenGardiner force-pushed the j1939-soft-sockets-again branch from fbcb5a9 to 4757249 Compare September 14, 2026 13:12
@BenGardiner

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I noticed that in the rebase of the scanner code to your replacement soft socket the scanners were no longer cleanly relying on sr() / sr1() via answers() logic. I'll work on bringing that back, fixing the things above I didn't have questions about and then refactoring the scanners to use the answers() logic...

@BenGardiner
BenGardiner force-pushed the j1939-soft-sockets-again branch 3 times, most recently from 97acab8 to f664c8a Compare September 17, 2026 09:58
@BenGardiner

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Hi @polybassa while I think this is ready for your next review, it might not be merged in this form. There are 'Feature' commits and then 'fixes' on them. e.g. FFfffFffFfffffFfff. To merge you would probably want the fixes squashed into the features. You may even want one squashed commit -- in which case you might consider merging the first commit separately since it is implementing missing sr1() functionality in the current J1939SoftSocket on master.

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codecov Bot commented Sep 17, 2026 •

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Codecov Report

❌ Patch coverage is 92.49049% with 79 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.33%. Comparing base (5376fcc) to head (21dd012).

Files with missing lines Patch % Lines
scapy/contrib/automotive/j1939/j1939_scanner.py 93.16% 35 Missing ⚠️
scapy/contrib/j1939.py 92.47% 21 Missing ⚠️
scapy/contrib/automotive/j1939/j1939_dm.py 83.56% 12 Missing ⚠️
scapy/contrib/automotive/j1939/j1939_dm_scanner.py 92.74% 9 Missing ⚠️
scapy/contrib/automotive/j1939/__init__.py 92.30% 1 Missing ⚠️
scapy/contrib/automotive/j1939/j1939_name.py 97.95% 1 Missing ⚠️
Additional details and impacted files
@@            Coverage Diff             @@
##           master    #5164      +/-   ##
==========================================
+ Coverage   80.89%   81.33%   +0.43%     
==========================================
  Files         394      399       +5     
  Lines       98710    99715    +1005     
==========================================
+ Hits        79853    81101    +1248     
+ Misses      18857    18614     -243     
Files with missing lines Coverage Δ
scapy/layers/can.py 93.07% <100.00%> (+0.03%) ⬆️
scapy/contrib/automotive/j1939/__init__.py 92.30% <92.30%> (ø)
scapy/contrib/automotive/j1939/j1939_name.py 97.95% <97.95%> (ø)
scapy/contrib/automotive/j1939/j1939_dm_scanner.py 92.74% <92.74%> (ø)
scapy/contrib/automotive/j1939/j1939_dm.py 83.56% <83.56%> (ø)
scapy/contrib/j1939.py 92.40% <92.47%> (+2.67%) ⬆️
scapy/contrib/automotive/j1939/j1939_scanner.py 93.16% <93.16%> (ø)

... and 20 files with indirect coverage changes

🚀 New features to boost your workflow:
  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

@BenGardiner
BenGardiner force-pushed the j1939-soft-sockets-again branch 3 times, most recently from 3b5967c to 4d7cb29 Compare September 17, 2026 12:41
@BenGardiner

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I'm going to look closer at https://github.com/secdev/scapy/actions/runs/35222531093/job/105206012569?pr=5164 -- that seems like there could be something wrong with the soft socket...

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I'm going to look closer at https://github.com/secdev/scapy/actions/runs/35222531093/job/105206012569?pr=5164 -- that seems like there could be something wrong with the soft socket...

yep that was a race in close() of the soft socket -- just like we had in isotp soft socket.

I have a fix

@BenGardiner
BenGardiner force-pushed the j1939-soft-sockets-again branch 5 times, most recently from 35d5188 to 625c334 Compare September 17, 2026 21:30
@BenGardiner

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sorry the checks may be skipped now due to a rate limit...

I think I resolved them but pretty hard to tell locally without waiting for the github runners

@BenGardiner
BenGardiner force-pushed the j1939-soft-sockets-again branch from 625c334 to 58adda4 Compare September 17, 2026 21:42
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no sorry. skipped due to a typo.

@BenGardiner
BenGardiner force-pushed the j1939-soft-sockets-again branch from 58adda4 to 811dfd9 Compare September 17, 2026 23:28
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ok... ok well that was a journey... over to you then @polybassa

@BenGardiner
BenGardiner force-pushed the j1939-soft-sockets-again branch 9 times, most recently from 026d8b3 to 8a5d63a Compare October 7, 2026 18:07
@polybassa

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Thanks for the updates. Please let me know when your are finished so that I can do another detailed review.

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Thanks for the updates. Please let me know when your are finished so that I can do another detailed review.

yep will do -- we're not there yet

@BenGardiner
BenGardiner force-pushed the j1939-soft-sockets-again branch from 8a5d63a to 3a9af4d Compare October 7, 2026 23:14


@dataclass
class DmScanResult:

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Is it necessary to have two almost identical result containers?

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No.

I was going to remove these I think



@dataclass
class J1939ScanResult:

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And another one

@BenGardiner
BenGardiner force-pushed the j1939-soft-sockets-again branch 8 times, most recently from b5a0b46 to 2b54cd6 Compare October 11, 2026 17:49
AI-Assisted: Yes Kimi 2.7 / GPT 5.4 codex / Copilot
@BenGardiner
BenGardiner force-pushed the j1939-soft-sockets-again branch 2 times, most recently from 43a73f0 to e73a064 Compare October 11, 2026 19:16
…allback (heuristic)

Implement answers(), clone_with(), and copy() on J1939 to support sr1()
for directed and broadcast requests with session tracking and fallback
heuristics.

Add identifier property and setter to J1939_CAN to satisfy the CAN
interface for python-can backends, and add a defensive fallback in
_can_send() converting to CAN on AttributeError.

AI-Assisted: yes (Gemini 3.8 Flash)
@BenGardiner
BenGardiner force-pushed the j1939-soft-sockets-again branch from e73a064 to c11ef08 Compare October 11, 2026 19:48
Adds a scanner to identify Controller Applications in a J1939 network,
various scanning techniques are provided including both broadcast and
unicast.

AI-Assisted: yes (Gemini 3.8 Flash)
@BenGardiner
BenGardiner force-pushed the j1939-soft-sockets-again branch from c11ef08 to 21dd012 Compare October 12, 2026 02:56
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4 participants