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

[Ari Timonen <Ari.Timonen () synopsys com>]

Hello,

The specification I linked is newer by several years. The one I linked is
802.1AS-REV, Draft 8.0 (Sponsor Ballot)<http://www.ieee802.org/1/files/private/as-rev-drafts/d8/802-1AS-rev-d8-0.pdf>

But latest is a bit newer.

Link here: https://1.ieee802.org/tsn/802-1as-rev/

Yours, Ari


Date: Wednesday, 20. January 2021 at 12.46
To: wireshark-dev () wireshark org <wireshark-dev () wireshark org>
Subject: Wireshark dissector does not match spec for IEEE P802.1AS-Rev/D8.0
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

___________________________________________________________________________
Sent via:    Wireshark-dev mailing list <wireshark-dev () wireshark org>
Archives:    https://www.wireshark.org/lists/wireshark-dev
Unsubscribe: https://www.wireshark.org/mailman/options/wireshark-dev
             mailto:wireshark-dev-request () wireshark org?subject=unsubscribe