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Radiotap

Introduction | defined fields | suggested fields | rejected fields

TX flags

Bit Number
15
Structure
u16 flags
Required Alignment
2
Unit
bitmap

Properties of transmitted frames.

mask meaning
0x0001 Transmission failed due to excessive retries
0x0002 Transmission used CTS-to-self protection
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

Discussion

Used by NetBSD and Linux, clashes with ../hardware queue_ as used in OpenBSD.

The no-ack bit (0x0008) is used for uses of radiotap when frames are sent. Similarly, the no-seq bit (0x0010) is used to allow userspace to send frames with a specific sequence number (e.g. when transmitting fragments of a single frame one-by-one). When it is set, the frame should be transmitted with the sequence number included in the 802.11 MAC header of the frame as received from userspace, regardless of the state of the sequence counters in driver/hardware.