Re: [tcpdump-workers] Link type FlexRay
2016-01-15 21:35 GMT+01:00 Guy Harris : > > On Jan 15, 2016, at 10:44 AM, Guenter Ebermann > wrote: > > I don't know whether Hannes still works at X2E. You might want to try > sending an e-mail to him asking whether a format for DLT_FLEXRAY was ever > defined - and, if it has, asking him to send me a copy so that I can add it > to the link-layer header types page: > > http://www.tcpdump.org/linktypes.html > > (and, if any of the *others* were defined, to send those to me as well). > > If mail to him bounces, you could try contacting X2E to see if that > information is available, or if they ever supporting writing out files in > pcap or pcapng format. > > If they never wrote files out with a link-layer header type of 210 for > DLT_FLEXRAY/LINKTYPE_FLEXRAY, then you can use it for your own purposes - > send us the spec and I'll add it to the link-layer header types page. > > If they did, but they don't tell you what format they use, we can create a > new LINKTYPE_/DLT_ value for your format, and provide a public specification > for that one. I asked Hannes about DLT_FLEXRAY. He told me that they currently dont use pcap for FlexRay and have only used it in a limited scenario and that we are free to change the layout. The format represented the bitsream from the bus 1:1 without an additional header. The only deviation was the padding: the data was padded to align to 4 byte boundaries. This is my suggestion for an extension: I want to extend the frame by a "measurement-header": This header is added by the measurement device. It contains one bit for the FlexRay channel (A or B), a "data-type" enumeration and error-flags. Error-flags will be all kind of decoding errors which may be detected during capture of a FlexRay frame. That is: TSS, FSS, BSS, or FES violations. Header CRC or Frame CRC errors and all kind of "short-item-counts" that is, if not all bytes of the frame-bitstream could be captured. One enum-value of the "data-type" will be for a "data-frame", whereas a data frame would have exactly the same coding as on the FlexRay bus. The second enum-value of the "data-type" will be a "flexray-symbol", which contains the bitlength information of the captured FlexRay symbol (used for CAS and Wakeup). BR Günter ___ tcpdump-workers mailing list tcpdump-workers@lists.tcpdump.org https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers
Re: [tcpdump-workers] Link type FlexRay
On Jan 19, 2016, at 9:35 AM, Guenter Ebermann wrote: > I asked Hannes about DLT_FLEXRAY. > He told me that they currently dont use pcap for FlexRay and have only > used it in a limited scenario and that we are free to change the > layout. > The format represented the bitsream from the bus 1:1 without an > additional header. > The only deviation was the padding: the data was padded to align to 4 > byte boundaries. > > This is my suggestion for an extension: > > I want to extend the frame by a "measurement-header": This header is > added by the measurement device. It contains one bit for the FlexRay > channel (A or B), a "data-type" enumeration and error-flags. OK, so the new format is that the frame begins with a measurement header, which is followed by the bitstream from the bus? Is the bitstream from the bus padded in that fashion? >From the Wikipedia article on FlexRay (the first of the ISO standards the >article mentions costs CHF 118, so I'm not going to buy them immediately): https://en.wikipedia.org/wiki/FlexRay a frame consists of some framing bits at each end of the frame, with each octet in the frame containing 2 bits of per-byte framing followed by the 8 bits of the octet. Would LINKTYPE_FLEXRAY/DLT_FLEXRAY frames include all of those bits? If so, where does the padding appear? ___ tcpdump-workers mailing list tcpdump-workers@lists.tcpdump.org https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers
Re: [tcpdump-workers] Link type FlexRay
On Jan 19, 2016, at 5:50 PM, Guy Harris wrote: > OK, so the new format is that the frame begins with a measurement header, > which is followed by the bitstream from the bus? > > Is the bitstream from the bus padded in that fashion? > > From the Wikipedia article on FlexRay (the first of the ISO standards the > article mentions costs CHF 118, so I'm not going to buy them immediately): > > https://en.wikipedia.org/wiki/FlexRay > > a frame consists of some framing bits at each end of the frame, with each > octet in the frame containing 2 bits of per-byte framing followed by the 8 > bits of the octet. Would LINKTYPE_FLEXRAY/DLT_FLEXRAY frames include all of > those bits? If so, where does the padding appear? (I'm assuming here that one packet in a pcap or pcapng file with type LINKTYPE_FLEXRAY corresponds to a FlexRay frame, of the sort described at http://www.ni.com/white-paper/3352/en/#toc4 under "Frame Format".) ___ tcpdump-workers mailing list tcpdump-workers@lists.tcpdump.org https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers
Re: [tcpdump-workers] Link type FlexRay
> Am 20.01.2016 um 03:00 schrieb Guy Harris : > > On Jan 19, 2016, at 5:50 PM, Guy Harris wrote: > >> OK, so the new format is that the frame begins with a measurement header, >> which is followed by the bitstream from the bus? Yes. It only contains additional information. The idea is that the simplest measurement device (i.e. a device using a normal FlexRay controller), which only receives valid frames will also be able to generate the format. In this case no error flag will be set and only valid frames will be contained in the pcap(ng) file. >> Is the bitstream from the bus padded in that fashion? No. >> From the Wikipedia article on FlexRay (the first of the ISO standards the >> article mentions costs CHF 118, so I'm not going to buy them immediately): >> >> https://en.wikipedia.org/wiki/FlexRay >> >> a frame consists of some framing bits at each end of the frame, with each >> octet in the frame containing 2 bits of per-byte framing followed by the 8 >> bits of the octet. Would LINKTYPE_FLEXRAY/DLT_FLEXRAY frames include all of >> those bits? If so, where does the padding appear? > > (I'm assuming here that one packet in a pcap or pcapng file with type > LINKTYPE_FLEXRAY corresponds to a FlexRay frame, of the sort described at > > http://www.ni.com/white-paper/3352/en/#toc4 > > > under "Frame Format".) Yes, I will provide you with a PDF with a detailed description of the packet for further discussion. ___ tcpdump-workers mailing list tcpdump-workers@lists.tcpdump.org https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers
