[PATCH 01/41] rxrpc: Fix RTT determination to use PING ACKs as a source
Jeffrey E Altman
jaltman at auristor.com
Fri Nov 10 13:54:46 PST 2023
On 11/10/2023 12:25 PM, David Howells wrote:
> Jeffrey E Altman<jaltman at auristor.com> wrote:
>
>>> I do ignore ack.serial == 0 for this purpose.
>> Zero has the special meaning - this ACK is not explicitly in response to a
>> received packet.
>>
>> However, as mentioned, the serial number counter wraps frequently and most
>> RxRPC implementations
>> do not transition from serial 0xffffffff -> 0x00000001 when wrapping.
> I don't skip zero serial numbers either. I'm not sure whether it would be
> better to do so.
If a DATA packet is sent with serial number zero and an ACK packet is
sent in response to it
with the ack.serial field set to the DATA packet serial number (zero),
then the receiver of the
ACK will be unable to compute an RTT from that DATA packet. It will
happen rarely but it
will happen.
Jeffrey
-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 4039 bytes
Desc: S/MIME Cryptographic Signature
URL: <http://lists.infradead.org/pipermail/linux-afs/attachments/20231110/8d2521c4/attachment.p7s>
More information about the linux-afs
mailing list