Re: Wireshark dissector does not match spec for IEEE P802.1AS-Rev/D8.0

[Alexis La Goutte <alexis.lagoutte () gmail com>]

Hi Ari,

Can you open an issue on gitlab wireshark ? with a pcap and link to spec ?

Cheers

On Wed, Jan 20, 2021 at 5:46 PM Ari Timonen <Ari.Timonen () synopsys com>
wrote:

> Hello,
>
> The time synchronization protocol IEEE P802.1AS dissector does not parse
> TLV flags correctly.
>
> The specification IEEE P802.1AS-Rev/D8.0 page 155 has the correct TLV
> flags.
>
> 1. The computeNeighbourRateRatio is first bit not second.
>
> 2. The computeMeanLink delay is the second bit
> 3. The oneStepReceiveCapable is the third bit.
> 4. The computeNeighborPropDelay flag does not exist.
>
> It could be because the packet is dissected as PTP2 packet.
>
> Precision Time Protocol (IEEE1588)
>
>     0001 .... = transportSpecific: 0x1
>
>         ...1 .... = 802.1as conform: True
>
>     .... 1100 = messageId: Signalling Message (0xc)
>
>     0001 .... = Reserved: 1
>
>     .... 0010 = versionPTP: 2
>
>     messageLength: 60
>
>     subdomainNumber: 0
>
>     Reserved: 0
>
>     flags: 0x0008
>
>         0... .... .... .... = PTP_SECURITY: False
>
>         .0.. .... .... .... = PTP profile Specific 2: False
>
>         ..0. .... .... .... = PTP profile Specific 1: False
>
>         .... .0.. .... .... = PTP_UNICAST: False
>
>         .... ..0. .... .... = PTP_TWO_STEP: False
>
>         .... ...0 .... .... = PTP_ALTERNATE_MASTER: False
>
>         .... .... ..0. .... = FREQUENCY_TRACEABLE: False
>
>         .... .... ...0 .... = TIME_TRACEABLE: False
>
>         .... .... .... 1... = PTP_TIMESCALE: True
>
>         .... .... .... .0.. = PTP_UTC_REASONABLE: False
>
>         .... .... .... ..0. = PTP_LI_59: False
>
>         .... .... .... ...0 = PTP_LI_61: False
>
>     correction: 0.000000 nanoseconds
>
>         correction: Ns: 0 nanoseconds
>
>         correctionSubNs: 0 nanoseconds
>
>     Reserved: 0
>
>     ClockIdentity: 0xacde48234567abcd
>
>     SourcePortID: 1
>
>     sequenceId: 1
>
>     control: Sync Message (0)
>
>     logMessagePeriod: 127
>
>     targetPortIdentity: 0xffffffffffffffff
>
>     targetPortId: 65535
>
>     Message Interval Request TLV
>
>         tlvType: Organization extension (3)
>
>         lengthField: 12
>
>         organizationId: IEEE 802 (0x0080c2)
>
>         OrganizationSubType: 2
>
>         linkDelayInterval: 13
>
>         timeSyncInterval: 14
>
>         announceInterval: 15
>
>         flags: 0x07
>
>             .... ..1. = computeNeighborRateRatio: True
>
>             .... .1.. = computeNeighborPropDelay: True
>
> Yours,
> Ari Timonen
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