On Mon, Jun 03, 2002 at 05:26:25PM +0200, [EMAIL PROTECTED] wrote:
> I'd like to monitor MAC frame CRC Errors rate in order to display
> stats saying which adapters are the sources of errors.
> 
> To do this, I need that ethereal say something like in Ethernet section :
> MAC Checksum: 0x????? (incorrect)
> 
> What do you suggest me to do ?

I suggest you find some way of doing this that doesn't involve capturing
frames with CRC errors and, with those frames, supplying either an
indication of whether the CRC was good or supplying the CRC itself,
because, in order to do that, you're going to have to modify the
*network interface drivers* to provide those frames to the underlying OS
mechanism used by libpcap (BPF on BSD, sockets on Linux, NDIS on
Windows, etc.) *and* to supply the "CRC bad" indication or supply the
CRC.

Most drivers do not, I suspect, ever supply frames with bad CRC values
to the mechanism in question.  I think the FreeBSD Intel Ethernet
Express 100PRO driver (the "fxp" driver) will do so in promiscuous mode
- *BUT* I don't think it'll indicate whether the CRC was bad or supply
the CRC as part of the packet data (and don't have time to look at the
driver, and the Intel documentation, to see whether it does).

If all you want are per-interface statistics showing the packet rate and
the bad-CRC-error packet rate, it may be that there are ways of getting
those statistics from the OS.  I suggest you look at trying to get those
statistics from the OS somehow.
-
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