On Thu, Jan 07, 2010 at 03:26:32AM -0800, Guy Harris wrote: > > On Jan 7, 2010, at 1:48 AM, p...@wsh.sbrk.co.uk wrote: > > > TCP has a tcp_dissect_pdus() function that higher protocols can use > > to eliminate their dependency on the TCP framing. Is there anything > > generic for other layers? I'm writing a USB dissector which is really > > a serial protocol being transported over USB. > > That's > > http://www.nordicsemi.com/files/Product/data_sheet/User_guide_ANT.pdf > > right?
Correct. I've dissected most of the ANT commands and ANT+ device profiles and am now doing the device to PC data transfers which are mainly over burst transfers. That's for dissecting Garmin Forerunner 50, 310XT etc. > If so, and if you're reassembling the packets in a burst transfer, this > isn't a byte stream, so you can ignore the TCP dissector, and look instead > at the IP dissector for an example. It's not *quite* the same as IP, as Well, I am reassembling the packets in a burst transfer, but first of all I have to reassemble the bytes in the USB transfer which is just a byte stream. i.e. the stream is a sequence of [A4,len,cmd,[len bytes],chksum] with occasional trailing null(s) and there maybe be more than one ANT packet in a USB packet. Potentially, the ANT packets could also span multiple USB packets. So that's the problem I'm trying to solve at the moment. > 1) you have sequence numbers rather than byte offsets, so you'd > use fragment_add_seq_check() rather than fragment_add_check(); I am doing that for the burst transfers. > 2) the sequence number wraps around, so you'd have to keep > some state and provide a "synthesized" sequence number that doesn't > wrap around. I'm doing that too. My code so far is here: git://e2c3.com/nant.git in packet-ant.c Cheers, Paul ___________________________________________________________________________ Sent via: Wireshark-dev mailing list <wireshark-dev@wireshark.org> Archives: http://www.wireshark.org/lists/wireshark-dev Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev mailto:wireshark-dev-requ...@wireshark.org?subject=unsubscribe
