[tcpdump-workers] Link-layer header type request for DisplayPort AUX channel
From: Dirk Eibach I need a link-layer header type value for DisplayPort AUX channel. Description: DisplayPort AUX channel monitoring data as specified by VESA DisplayPort(DP) Standard preceeded by a pseudo-header. LINKTYPE_DPAUX Packet structure (all fields are 8 Bit wide) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Packet Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Payload | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Packet Type DATA +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Type DATA(0x00)| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | From Sink(0x00)/Source(0x01) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |AUX channel data | This is the actual Data as specified by the DisplayPort standard. It is preceded by the information if the Data was sent from the Sink(e.g. a display) or from the Source(e.g. a graphics card). Packet Type EVENT +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Type EVENT(0x02) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Input Status | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ One of the monitored input signals has changed its value. Input status encoding: Bit 0: HPD (Hot Plug Detect) Bit 1-7: Application specific Packet Type START +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Type START(0x03) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Input Status | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ A monitor session was started. Inputs status encoding as specified in EVENT packet description. Packet Type STOP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Type STOP(0x04)| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ A monitor session was stopped. ___ tcpdump-workers mailing list tcpdump-workers@lists.tcpdump.org https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers
Re: [tcpdump-workers] Link-layer header type request for DisplayPort AUX channel
2018-04-23 18:41 GMT+02:00 Michael Richardson : > > What kind of capture system/software can read data from this channel and save > as pcap? For capturing I use the Unigraf DPA-400 DisplayPort AUX channel monitor. There is only proprietary Windows driver and application available. I did some reverse enigineering and wrote a wireshark extcap driver for the device. I also added a dissector and a wiretap for the logfiles from the original application. All this shall be posted soon, that's what I need the header type value for. > Is the VESA specification publically available? Sadly the VESA specification is only available to (paying) members :( > > Would you like to put your Packet Structure on a web site so we can point to > it? > If you don't have a site handy, please send a pull request against > https://github.com/the-tcpdump-group/tcpdump-htdocs > with your description in a new file. I've changed the name, because > putting "LINKTYPE" in the name is kinda redundant. I did a pull request as suggested. Cheers Dirk ___ tcpdump-workers mailing list tcpdump-workers@lists.tcpdump.org https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers
