tcpdump mailing list archives
Re: decode MPLS-contained packets?
From: Francois-Xavier Le Bail via tcpdump-workers <tcpdump-workers () lists tcpdump org>
Date: Tue, 5 May 2020 16:01:19 -0400 (EDT)
--- Begin Message --- From: Francois-Xavier Le Bail <devel.fx.lebail () orange fr>
Date: Tue, 5 May 2020 22:03:00 +0200
On 05/05/2020 21:44, Gert Doering wrote:We should print "PW Ethernet Control Word" and the "Sequence Number", 2 last 2 octets of the 4. Like: PW Ethernet Control Word, Sequence Number xxxI think we should only print this if "-v" is given. Most of the time, both control word and sequence number are of little interest. I really like tcpdump's very compact "only the most relevant info" output format (by default).OK for "-v" only print. Other information from Francesco Fondelli: ----------------------------------------------------------------------- it is a bit more complicated than that, look for /* * No, there isn't, so use the 1st nibble logic (see BCP 4928, * RFC 4385 and 5586). */ in https://code.wireshark.org/review/gitweb?p=wireshark.git;a=blob;f=epan/dissectors/packet-mpls.c;h=4ecb10d1216077b92e6d4ca2520340cf053414f4;hb=HEAD and also the PW ETH heuristic in looks_like_plain_eth https://code.wireshark.org/review/gitweb?p=wireshark.git;a=blob;f=epan/dissectors/packet-pw-eth.c;h=aec7b662d38ddb36514ed3c213df47ad53ad610b;hb=HEAD Wireshark MPLS heuristic is not perfect and has been criticized but is still there :-) hopefully correctly parsing your data as well. For tcpdump maybe a -T based approach is better? -T mpls (+ 1st nibble logic for IPv4/IPv6) -T ethpw -T ethpwnocw ... ----------------------------------------------------------------------- Probably some more work to do... And probably linked to https://tools.ietf.org/html/rfc8469. -- Francois-Xavier
--- End Message ---
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- Re: decode MPLS-contained packets?, (continued)
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- Re: decode MPLS-contained packets? Francois-Xavier Le Bail via tcpdump-workers (May 05)
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- Re: decode MPLS-contained packets? Gert Doering via tcpdump-workers (May 05)
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- Re: decode MPLS-contained packets? Francois-Xavier Le Bail via tcpdump-workers (May 05)
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- Re: decode MPLS-contained packets? Gert Doering via tcpdump-workers (May 05)
- Re: decode MPLS-contained packets? Gert Doering via tcpdump-workers (May 05)
- Re: decode MPLS-contained packets? Guy Harris via tcpdump-workers (May 07)
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- Re: decode MPLS-contained packets? Francois-Xavier Le Bail via tcpdump-workers (May 05)
- Re: decode MPLS-contained packets? Francois-Xavier Le Bail via tcpdump-workers (May 05)
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- Re: decode MPLS-contained packets? Gert Doering via tcpdump-workers (May 05)
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- Re: decode MPLS-contained packets? Francois-Xavier Le Bail via tcpdump-workers (May 05)
- Re: decode MPLS-contained packets? Guy Harris via tcpdump-workers (May 07)
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- Re: decode MPLS-contained packets? Gert Doering via tcpdump-workers (May 07)
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- Re: decode MPLS-contained packets? Francois-Xavier Le Bail via tcpdump-workers (May 06)
- Re: decode MPLS-contained packets? Francois-Xavier Le Bail via tcpdump-workers (May 07)
- Re: decode MPLS-contained packets? Guy Harris via tcpdump-workers (May 07)
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- Re: decode MPLS-contained packets? Francois-Xavier Le Bail via tcpdump-workers (May 07)
- Re: decode MPLS-contained packets? Gert Doering via tcpdump-workers (May 07)
- Re: decode MPLS-contained packets? Francois-Xavier Le Bail via tcpdump-workers (May 07)
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- Re: decode MPLS-contained packets? Francois-Xavier Le Bail via tcpdump-workers (May 08)