802.11 adhoc / IBSS support

There's IBSS / Adhoc support in net80211 and a variety of drivers.

Overview

TBD

Examples

TBD

Encryption

WPA-NONE encryption works at the moment:

ap_scan=2

network={
ssid="CACHEBOY_IBSS_ENCRYPT"
psk="xxxxxxxxxxxxxxxx"
# set ibss
mode=1
proto=WPA
key_mgmt=WPA-NONE
pairwise=NONE
group=CCMP
}

WPA-RSN encryption is not yet implemented.

Capabilities negotiation / 802.11n support

One of the pesky corner cases in 802.11 IBSS is negotiating capabilities between IBSS nodes. Traditionally it wasn't done - you just expected that the remote node supported mostly the same capabilities as you. This is a problem when things like 802.11b versus 802.11bg support - the 802.11bg node may just default / expect that 802.11bg rates are available for all nodes, even the 802.11b node.

How this is supposed to happen is:

Nodes discover each other through hearing beacons, broadcast traffic, and such
Nodes exchange probe request/responses to negotiate a subset of full 802.11 functionality
Nodes then use OPEN authentication frames to reset each others' state (eg encryption IV state, sequence number state, etc) so reassociation is reliable.

FreeBSD doesn't do all of this (it only learns through beacons, broadcast traffic, and receiving probe requests.) This makes various kinds of negotiation difficult.

There's also interoperability with other devices - for example, it looks like the broadcom firmware only treats an IBSS node as 11n enabled if the probe request received by it contains 802.11n IEs.