[Patch 3/3] Network steering feature

Jouni Malinen j at w1.fi
Sun Oct 16 07:16:15 PDT 2016

On Sun, Oct 16, 2016 at 04:53:42PM +0300, Jouni Malinen wrote:
> While getting a new Ethertype for hostapd purposes would be kind of
> convenient, I'm not exactly fond of the $3095 registration fee..
> Subtyping an existing Ethertype would likely be a more supportable
> approach.

It looks like there is already a standard defined mechanism for
assigning identifiers for prototyping and vendor-specific protocol
development needs. While this is couple of octets longer and does not
get the convenience of being able to filter frames simply based on
Ethertype in a socket, this may be the most convenient approach to use
here since I can define new values based on an OUI 00:13:74 that is
managed based on hostap.git commits.

IEEE Std 802-2014, Clause 9.2.4 defines an OUI Extended EtherType 88-B7.
I could use that design to assign the following identifier for
hostapd/wpa_supplicant uses:

EtherType: 88 B7 (OUI Extended EtherType)
Protocol identifier: 00 13 74 00 01 (OUI 00:13:74 followed by two octet
vendor-specific subtype 0x0001 that I'd assign to hostap.git purposes)

This would then be followed by a hostap.git specific subtype and we
could assign this as a single octet where 0x00 would be used to replace
the current FT pull/resp/push messages that misuse the IEEE 802.11r
defined Ethertype. Another subtype, say 0x01, could be assigned for the
network steering feature. Or alternatively, we can use the same subtype
for both if that is more convenient. In any case, there would be
sufficient flexibility to define whatever header needs we have for
AP-to-AP communication with hostapd.

As a more complete example, the FT R0KH-R1KH pull message could start
with this (showed with IEEE 802.3 MAC header):
Destination MAC Address (6 octets)
Source MAC Address (6 octets)
EtherType = 0x88 0xB7
   (end of IEEE 802.3 MAC header)
Protocol identifier = 0x00 0x13 0x74 0x00 0x01
hostap.git subtype = 0x00 (FT-AP-AP-protocol)
Jouni Malinen                                            PGP id EFC895FA

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