Re: "final" radiotap patch for tcpdump

[David Young <dyoung () pobox com>]

On Sun, Sep 19, 2004 at 02:02:05PM -0700, Guy Harris wrote:
> "pcap_is_swapped(p)" returns "true" if the capture file you've opened
> was captured on a machine with a different byte order, based on the byte
> order of the magic number - if that matches the byte order of the
> radiotap values, that'd be sufficient.
>
> (It always returns "false" for live captures.)

"Oh."  Have we got the stomach for radiotap v2?  If big-endian kernels
no longer have to convert fields to little-endian, I think that puts
the second-to-last performance issue to rest.

[The "last" performance issue is that libpcap & tcpdump don't grok
variable-length headers, so radiotap headers are padded to a whopping
64 bytes.  A roadmap: v2 pads to just 48 or 32 bytes (maybe not...);
v3 eliminates the need for padding.  Thoughts?]

I'm getting WAY ahead of myself.  First thing is to wrap up importing
tcpdump into NetBSD.  Next is to find more free time for 802.11 hacking.

Dave

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David Young             OJC Technologies
dyoung () ojctech com      Urbana, IL * (217) 278-3933
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