Hello.
On 14/12/16 17:49, Alexander Aring wrote:
Hi,
On 12/14/2016 08:20 AM, Xue Wenqian wrote:
Hi,
Recently I find a wpan-ping problem: wpan-ping process is always
running, when there is another process runing on wpan interface, which
will also transmit packets via wpan, the non-wpanping packets will also
be received by recv() of wpan-ping, leading to the "Sequence number did
not match" problem. It seems that the recv() function can not filter out
non-wpanping packets.
That is correct. Especially on the server side we do no filtering at all
and just send back the (hopefully) wpan-ping frame.
Please go ahead and send your patch with the filtering you suggest and
we can discuss what we can take and what not.
In my opinion:
So the currently known other upper layer protocol is 6LoWPAN. According
to 6LoWPAN dispatches [0]:
00 xxxxxx 0 NALP
so the wpan-ping dataframe should start with the bit pattern 00.
That is already done. The wpan-ping packet send out from the client
already has this set.
Then for extra stuff the payload should do some checksum stuff, e.g.
ICMPv6 at tail -> if it doesn't match drop it.
Then most frames will be filtered, the rest is the usual header parsing,
if it doesn't match there -> drop it.
As written above nothing is checked or filtered on the server side yet.
If there are good suggestions I happily take them in. Let's wait for the
patch from Xue to see what he had in mind.
Stefan Schmidt
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