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TLV fields in radiotap

Bit Number:
list of TLVs detailed below
Required alignment

If this bit is set higher bits may not be set (as they cannot be parsed, given the variable length of this field) and the data of this field fills the remaining radiotap data (as indicated by the length field in the header); the data is understood as a type-length-value item list with the following item structure:

The type is taken from the regular radiotap type (bit) allocation, but the special values 29 and 31 are not valid.

The vendor namespace type (30) may be used as a TLV field, but has the following modified format as a TLV:

If field alignment is necessary beyond the 4-byte alignment, type 28 (i.e. this field value) shall be used as padding with an appropriate length (which would likely often be 0 for 8-byte alignment). This ensures parser simplicity, it doesn’t need to be aware of alignment rules.

Generators should generate data in fields with type < 28 in regular non- TLV fields, this ensures backward compatibility.

Generators shall use TLV fields for all fields with type >= 32.

Parsers shall be able to parse TLV fields with partial data present as indicated by the length of the data, i.e. producers can omit bytes they don’t fill at the end of the data. Such bytes are assumed to be 0.