802.11s mesh powersaving for linux

Scope

Implement non-realtime powersaving features of 802.11s draft:

powersaving level indication;

traffic buffering for sleeping peers;

TIM/DTIM in beacons;

peer service period;

Provide powersaving level control on MSTA/peer link basis;

Provide peer link control;

Approach

Enhance current in-kernel 802.11s implementation:

powersaving scheme proposed by 802.11s draft closely resemble AP-based scheme (traffic buffering/TIM/DTIM), so this code may be reused;

powersaving level indication (both peer and non-peer)/mesh awake window attributes need to be added;

wakeup for peer beacon reception may be implemented later, now it's enough to stay awake continuously and just calculate whether station would actually hear the frames that it receives;

peer service period logic need to be added, it's a simple state machine;

Testing may be carried out with mac80211_hwsim driver.

What's to be done

MSTA power mode tracking (11C.13.3);

each peering power mode tracking (11C.13.4);

TIM/DTIM in beacons (11C.13.5-6) – ieee80211_beacon_get_tim;

mesh awake window (11C.13.7);

wake-up scheduling for peer beacons (optional);

ps-poll requests and responses (?);

service period tracking (11C.13.10);

frame buffering for doze peers – ieee80211_tx_h_multicast_ps_buf, ieee80211_tx_h_unicast_ps_buf;

user interface controls – like nl80211_set_power_save;