Hi,Sorry for the delay, I wanted to check the code first. See my answer inline.
Le 2013-03-05 21:20, Alan Ott a écrit :
Actually, the patch I have for fragmentation (not integrated in net-next yet) does not cover this particular issue. The current code leaves the first fragment empty (i.e. with no payload), this is what it fixed in my patch. Ralph is right when he says that the datagram_size field (as per RFC 4944 Section 5.3) is not correctly set (it is currently computed over the compressed 6LoWPAN header).On 03/05/2013 02:38 PM, Ralph Droms (rdroms) wrote:On Mar 5, 2013, at 10:59 AM 3/5/13, Wolf-Bastian Pöttner <poett...@ibr.cs.tu-bs.de> wrote:The most recent version of 6lowpan.c that I pulled will interoperate with other instances of that same code, but not with different codebases.Hi!Am 20.02.2013 um 03:00 schrieb Ralph Droms (rdroms) <rdr...@cisco.com>:What I want to do is update the header compression and fragmentation code so it interoperates using header compression. I think I have code for header compression and send-side fragmentation. I still need to work on the receive-side fragmentation.Am I right in assuming, that fragmentation between two linux devices is not supposed to work at the moment?6lowpan.c inserts a fragment offset based on the compressed header, while as I read the relevant RFCs, the offset should be based on the uncompressed header.Yes, it should be based on the uncompressed header. That's one of thethings Tony Cheneau fixed. I'm not sure whether that's in his patch setthat's not upstream yet.
I attached a capture of a fragmentation when using my current patches. Reported datagram size is 227, while it should be 248 (I believe).
Because both the fragment generation and fragment reassembly code use the offset in the same way, 6lowpan.c will interoperate with itself but not, e.g., Contiki or XINU code.I'm sure we fixed that (at least in some case). Tony can confirm.
I wonder why it works, but it might be just out of pure luck.
As I wrote, I have a fix for fragment generation that has been tested with Contiki (but has not been committed). I haven't had time to get back to the code to fix the fragment reassembly code.
Regards, Tony
6lowpan-wrong-datagram-size.pcap
Description: application/vnd.tcpdump.pcap
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