Wireshark · Wireshark-dev: Re: [Wireshark-dev] MPLS Echo Packet containing FEC stack change Sub-TLV in DDMAP TLV is not decoded

[Jaap Keuter <jaap.keuter@xxxxxxxxx>]

Hi,

Thanks for the illustrative capture files. There's nothing better then to have that, so that we can look straight at the problem.

I've used them to open an issue here: https://gitlab.com/wireshark/wireshark/-/issues/17868 which I can use to resolve the problem.

Thanks,

Jaap

Op 10-01-2022 17:13 schreef max payne.. <pankaj.knitcs1@xxxxxxxxx>:

Hi Jaap,

Thanks for your response.

Please find the attached wireshark capture for "multiple FEC stack change TLV" and "FEC stack change with Target FEC TLV" not decoded properly.

Also the bytes sent in mail below are complete encapsulation with all headers and those bytes can be directly copied to online hex-decoder for a quick look.

On Fri, Jan 7, 2022 at 12:31 PM Jaap Keuter <jaap.keuter@xxxxxxxxx> wrote:

Hi,

The immediate response by Alexis was to open an issue on the Wireshark issue tracker.

My response would be to attach a small sample capture file with the packets, instead of some bytes or screenshot to the email.

Can you do either of those?

Jaap

On 6 Jan 2022, at 06:31, max payne.. <pankaj.knitcs1@xxxxxxxxx> wrote:

Hi Team,

I have not got the resolution for the issue below.

This was the link provided to me.

https://www.wireshark.org/mailman/confirm/wireshark-dev/d4b89dd02f824a954e2e3ffa37151bf0f7ebacbc

On Fri, Dec 3, 2021 at 12:27 AM max payne.. <pankaj.knitcs1@xxxxxxxxx> wrote:

Hi,

This is to inform you that we are supporting FEC Stack Change Sub-TLV in DDMAP TLV. I have Hex Dump, which is correct as per my understanding but it is not getting decoded on Wireshark or Online Decoder.

Please let me know if the latest Wireshark  "Version 3.6.0 (v3.6.0-0-g3a34e44d02c9)" supports the following (RFC 8029  3.4.1.3. FEC Stack Change Sub-TLV) :-

1) Multiple FEC stack change sub-TLV in DDMap TLV, whereas single FEC stack change TLV is decoded properly. Please find the HEX dump below.

2) FEC stack change sub-TLV along with FEC stack sub-TLV in DDMap TLV is not decoded properly. Please find the HEX dump below.

I am having following HEX Dump, which is not getting decoded properly on wireshark or online decoder "https://hpd.gasmi.net/"

Two  FEC stack Sub-TLV in DDMAP TLV not decoded properly on wireshark or on https://hpd.gasmi.net/
Ethernet:   18 92 a4 55 71 04 00 23 8a fb c2 04 81 00 00 d4
08 00

IP: 45 00
IP Len: 00 68
71 a5 00 00 ff 11 29 a4 07 07
07 07 09 09 09 09

UDP: 0d af 0d af
UPD Len: 00 54
a8 b1

ECHO: 00 01
00 00 02 02 08 02 00 00 00 16 00 00 00 03 e4 ae
50 eb 6f c5 47 9d e4 ae 50 eb 70 2a dc 4c

DDMAP: 00 14 00 28
05 dc 01 02 d2 01 01 01 d2 01 01 01 00 00
SUB-Len: 00 18
             
Stack-chg Type: 00 03 00 08
Value : 02 01 00 00
06 06 06 06

Stack-chg Type: 00 03 00 08
Value : 02 01 00 00
07 07 07 07

FEC stack change sub-TLV with FEC sub-TLV (IGP IPV4 Prefix Segment TLV) not decoded properly on wireshark or on https://hpd.gasmi.net/.

Ethernet:   18 92 a4 55 71 04 00 23 8a fb c2 04 81 00 00 d4
08 00

IP: 45 00
IP Len: 00 68
71 a5 00 00 ff 11 29 a4 07 07
07 07 09 09 09 09

UDP: 0d af 0d af
UPD Len: 00 54
a8 b1

ECHO: 00 01
00 00 02 02 08 02 00 00 00 16 00 00 00 03 e4 ae
50 eb 6f c5 47 9d e4 ae 50 eb 70 2a dc 4c

DDMAP: 00 14 00 28
05 dc 01 02 d2 01 01 01 d2 01 01 01 00 00
SUB-Len: 00 18
             
Stack-chg Type: 00 03 00 08
Value : 02 01 0c 00
06 06 06 06

FEC TLV Type: 00 0e 00 08
Value : 01 01 01 01
 20 00 00 00

Whereas multiple Label-Stack sub-TLV in DDMap TLV is getting properly decoded on https://hpd.gasmi.net/

Ethernet: 18 92 a4 55 71 04 00 23 8a fb c2 04 81 00 00 d4
08 00

IP: 45 00
IP Len: 00 60
71 a5 00 00 ff 11 29 a4 07 07
07 07 09 09 09 09

UDP: 0d af 0d af
UPD Len: 00 4C
a8 b1

MPLS Echo: 00 01
00 00 02 02 08 02 00 00 00 16 00 00 00 03 e4 ae
50 eb 6f c5 47 9d e4 ae 50 eb 70 2a dc 4c

DDMAP: 00 14 00 20
05 dc 01 02 d2 01 01 01 d2 01 01 01 00 00
SUB-Len: 00 10
               
Label-S: 00 02 00 04
00 00 30 06

Label-S: 00 02 00 04
00 00 30 06

--

Pankaj Verma

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Pankaj Verma

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Pankaj Verma