Re: Two small problems with libpcap

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.