PTPv2 announce messages malformed

edit

Thanks for the capture. Simply looking at the first packet, it shows:

Precision Time Protocol (IEEE1588)
    0000 .... = transportSpecific: 0x0
    .... 1011 = messageId: Announce Message (0xb)
    0000 .... = Reserved: 0
    .... 0010 = versionPTP: 2
    messageLength: 110
....
    TimeSource: INTERNAL_OSCILLATOR (0xa0)
    Organization extension TLV
        tlvType: Organization extension (3)
        lengthField: 18
        organizationId: 00:00:0c (Cisco Systems, Inc)
        organizationSubType: Unknown (0x010000)
        dataField: 030000000000000000000000
[Malformed Packet: PTP]
    [Expert Info (Error/Malformed): Malformed Packet (Exception occurred)]
        [Malformed Packet (Exception occurred)]
        [Severity level: Error]
        [Group: Malformed]

0000  01 1b 19 00 00 00 00 b1 e3 74 13 01 88 f7 0b 02   .........t......
0010  00 6e 00 00 02 00 00 00 00 00 00 00 00 00 00 00   .n..............
0020  00 00 00 b1 e3 ff fe 74 13 00 00 01 5d 98 05 00   .......t....]...
0030  00 00 00 00 00 00 00 00 00 00 00 00 00 80 f8 fe   ................
0040  ff ff 80 00 b1 e3 ff fe 74 13 00 00 00 a0 00 03   ........t.......
0050  00 12 00 00 0c 01 00 00 03 00 00 00 00 00 00 00   ................
0060  00 00 00 00*00 09*00 38*00 00 00 00 00 00 00 00   .......8........
0070  00 00 00 00 00 00 00 03 55 54 43 00               ........UTC.

I've marked the next tag (0x0009) and length (0x0038) in the packet data. This tells there's a Alternate time offset indicator TLV with length 56. Clearly there are no 56 bytes left in the packet from that point. So the TLV seems malformed, as Wireshark reports.

Changing this length to 0x0014 (matching the actual amount of data left) results in:

TimeSource: INTERNAL_OSCILLATOR (0xa0)
Organization extension TLV
    tlvType: Organization extension (3)
    lengthField: 18
    organizationId: 00:00:0c (Cisco Systems, Inc)
    organizationSubType: Unknown (0x010000)
    dataField: 030000000000000000000000
Alternate time offset indicator TLV
    tlvType: Alternate time offset indicator (9)
    lengthField: 20
    keyField: 0
    currentOffset: 0
    jumpSeconds: 0
    timeOfNextJump: 000000000000
    displayName: UTC
        length: 3
        displayName: UTC

So this seems to indicate a bug in the software that created these PTP packets.