24 Nov
2010
24 Nov
'10
1:50 p.m.
On 23.11.2010 23:32, Erik Tews wrote:
Hi
I spotted two small problems with libpcap:
* Preables for received PP frames are missing, the dedected.org
tools used to include the preamble as well. This can easily be
fixed by adding a default preamble if the kernel doesn't report
the preamble to the userspace.
I guess the kernel should report it, at least with double simplex
bearers the sender can't be determined based on the slot number.
* The slottime wraps around at 2^12 and not at
2^11 as it used to
wrap around with the dedected.org tools. I am not sure about the
best solution here, one could also use the full 16 bits for the
time which are available in the header.
I'm not sure what you're referring to here. The slot numbers are in
the range of 0-23.
Generally I think the header format should be revamped:
- we don't need the fake ethernet addresses
- the preamble should use 5 bytes for the case of a prolonged
preamble
- the RSSI shouldn't use the raw COA values but defined units
- the multiframe number should be added
- the RF-band and/or specific frequency should be added. Using
the RF-band is probably the more flexible way.
- drift for received packets could be added
additionally we could optionally ignore S-field errors in the driver
and indicate them in the frame header.
The easiest way to make these changes is probably to add a new
link type for the new header and have wireshark etc. deal with
that.