On Thu, Mar 07, 2002 at 04:13:02PM -0500, Ebright, Don wrote:
> I tried some limited token-ring testing on AIX 5.1 and the results look good
> so far.

Have you run into the EFAULT problem yet?

> The timestamp conversion from nanoseconds to microseconds appears
> to be correct, and the linktype is reported as 1 for ethernet and 6
> (DLT_IEEE802 or LINKTYPE_TOKEN_RING) for token-ring.  This should allow
> platform transparency for those who need to move tcpdump capture files
> between different platforms.  Sadly, this is the very same value that the
> 'native' AIX tcpdump uses to indicate ethernet, which is sure to cause
> problems for the unwary.

Fortunately, it appears that AIX's libpcap uses a minor version number
of 2 in its capture files, rather than the minor version number of 4
that current libpcap uses.

The capture file reading library in Ethereal assumes that a libpcap
capture file with a minor version number of 2 and a link-layer type of 6
(Ethernet), 8 (a typo for 9 for Token Ring, which I'll fix now), or 15
(FDDI) is an AIX tcpdump capture file.

This leaves it vulnerable to misreading old libpcap capture files, but
libpcap has used a version of 4 going back at least as far as the last
LBL release, the 0.4 release, so I suspect a file with a version number
of 2 is more likely to be an AIX capture file than an old libpcap
capture file.

I don't know whether we'd want to put a similar hack into libpcap or
not.
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