Re: [OPSAWG] draft-gharris-opsawg-pcap.txt --- FCS length description

Carsten Bormann <cabo@tzi.org> Tue, 22 December 2020 03:03 UTC

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From: Carsten Bormann <cabo@tzi.org>
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Date: Tue, 22 Dec 2020 04:03:44 +0100
Cc: Pcap-ng file format <pcap-ng-format@winpcap.org>, tcpdump-workers <tcpdump-workers@lists.tcpdump.org>, opsawg@ietf.org
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To: Michael Richardson <mcr+ietf@sandelman.ca>
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Subject: Re: [OPSAWG] draft-gharris-opsawg-pcap.txt --- FCS length description
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On 2020-12-22, at 01:31, Michael Richardson <mcr+ietf@sandelman.ca> wrote:
> 
> #define LT_FCS_LENGTH(x)		(((x) & 0xF0000000) >> 28)
> #define LT_FCS_DATALINK_EXT(x)		((((x) & 0xF) << 28) | 0x04000000)
> 
> this suggests that the FCS length is really only 3 bits

4 bits, really (assuming 32-bit unsigned integers).

Grüße, Carsten