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From: Mathy Vanhoef <vanhoefm@gmail.com>
To: radiotap@netbsd.org
Subject: Proposed Tx flag: don't reorder frames
Date: Fri, 24 Jul 2020 09:58:35 +0400	[thread overview]
Message-ID: <CAFXAJYyqgCqhMB0sEY4t5K-PcCe4G1O6Ef1NYCpK=eZcuntVvw@mail.gmail.com> (raw)

Hello all,

I propose to add a DONT_REORDER bit to the existing TX flags field.
When this flag is set, injected frames shouldn't be reordered relative
to other frames that also have this flag set (even when these frames
have different QoS TID values).

This for example allows userspace to inject frames that have different
QoS TID fields while assuring that they are transmitted in the order
as they were injected. In practice this is useful to perform certain
experiments where the order of transmitted frames is important.

Concretely the proposal is to add the following Tx flag:

 |`0x0004` |Transmission used RTS/CTS handshake |
 |`0x0008` |Transmission shall not expect an ACK frame and not retry
when no ACK is received |
 |`0x0010` |Transmission includes a pre-configured sequence number
that should not be changed by the driver's TX handlers |
+|`0x0020` |Transmission should not be reordered relative to other
frames that have this flag set |

Proposed patches for Linux and some of its drivers can be found here:
https://lore.kernel.org/linux-wireless/20200724054724.105520-1-Mathy.Vanhoef@kuleuven.be/T/#t

Proposed change for wireshark which parses the Tx flags, including the
new don't order flag, is here:
https://code.wireshark.org/review/#/c/37944/

And a proposed update to scapy to recognize the don't order flag:
https://github.com/secdev/scapy/pull/2734

Note that on the radiotap website the TX flags field is still listed
under the "suggested fields" page, but I'm assuming that by now this
field is approved (since it's used in Linux)?

Best regards,
Mathy



             reply	other threads:[~2020-07-24  5:58 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-24  5:58 Mathy Vanhoef [this message]
2020-07-24 11:13 ` Proposed Tx flag: don't reorder frames Johannes Berg
2020-08-30  0:05   ` Mathy Vanhoef
2020-09-17  9:57     ` Johannes Berg
2020-10-01  5:59       ` Mathy Vanhoef

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