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ChargePoint / wireshark-v2g

Dissector for the V2G Protocols
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HomePlug AV broadcasts missing data #72

Open Andgun98 opened 3 months ago

Andgun98 commented 3 months ago

Hi,

I was troubleshooting some low level issues in an ISO session which turned out to be caused by a frequency offset problem. This made me notice that this V2G plugin does not decode all of the HomePlug AV broadcast data. I'll add screenshots of the same pcap decoded with a different plugin in comparison to this one.

image image

Just an idea for improving the capabilities of this plugin

JeremyWhaling commented 2 months ago

As far as I know, this dissector doesn't handle HomePlug AV packets, these are handled by a dissector bundled with Wireshark. Can you state what other plug in you used? Also, a PCAP would help (truncated to just SLAC phase would be fine).

ghost commented 2 months ago

@JeremyWhaling is correct, this plugin doesn't have any code to dissect HomePlug AV packets and uses the built-in Wireshark dissector. As always, if a better implementation is provided or a better library is available, we accept patches.

barsnick commented 2 months ago

Which Wireshark version and which plugins are you using?

My Qualcomm docs say this is a "VS_LNK_STATS_CNF", and there exists no "VS_GET_STATUS_CNF", but perhaps this packet is from a different vendor.

From looking at the code, Wireshark upstream supports this MME as HOMEPLUG_AV_MMTYPE_QUALCOMM_LNK_STATS_CNF ("LNK_STATS.CNF (Link Statistics Confirmation)") since v2.9.0:

https://gitlab.com/wireshark/wireshark/-/blob/master/epan/dissectors/packet-homeplug-av.c?ref_type=heads#L1007

That does look different from what both of your Wireshark screenshots show.