mac80211: mesh power save basics

Add routines to
- maintain a PS mode for each peer and a non-peer PS mode
- indicate own PS mode in transmitted frames
- track neighbor STAs power modes
- buffer frames when neighbors are in PS mode
- add TIM and Awake Window IE to beacons
- release frames in Mesh Peer Service Periods

Add local_pm to sta_info to represent the link-specific power
mode at this station towards the remote station. When a peer
link is established, use the default power mode stored in mesh
config. Update the PS status if the peering status of a neighbor
changes.
Maintain a mesh power mode for non-peer mesh STAs. Set the
non-peer power mode to active mode during peering. Authenticated
mesh peering is currently not working when either node is
configured to be in power save mode.

Indicate the current power mode in transmitted frames. Use QoS
Nulls to indicate mesh power mode transitions.
For performance reasons, calls to the function setting the frame
flags are placed in HWMP routing routines, as there the STA
pointer is already available.

Add peer_pm to sta_info to represent the peer's link-specific
power mode towards the local station. Add nonpeer_pm to
represent the peer's power mode towards all non-peer stations.
Track power modes based on received frames.

Add the ps_data structure to ieee80211_if_mesh (for TIM map, PS
neighbor counter and group-addressed frame buffer).

Set WLAN_STA_PS flag for STA in PS mode to use the unicast frame
buffering routines in the tx path. Update num_sta_ps to buffer
and release group-addressed frames after DTIM beacons.

Announce the awake window duration in beacons if in light or
deep sleep mode towards any peer or non-peer. Create a TIM IE
similarly to AP mode and add it to mesh beacons. Parse received
Awake Window IEs and check TIM IEs for buffered frames.

Release frames towards peers in mesh Peer Service Periods. Use
the corresponding trigger frames and monitor the MPSP status.
Append a QoS Null as trigger frame if neccessary to properly end
the MPSP. Currently, in HT channels MPSPs behave imperfectly and
show large delay spikes and frame losses.

Signed-off-by: Marco Porsch <marco@cozybit.com>
Signed-off-by: Ivan Bezyazychnyy <ivan.bezyazychnyy@gmail.com>
Signed-off-by: Mike Krinkin <krinkin.m.u@gmail.com>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c
index f920da1201a..35ac3887142 100644
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -261,6 +261,9 @@ mesh_add_meshconf_ie(struct sk_buff *skb, struct ieee80211_sub_if_data *sdata)
 	*pos = IEEE80211_MESHCONF_CAPAB_FORWARDING;
 	*pos |= ifmsh->accepting_plinks ?
 	    IEEE80211_MESHCONF_CAPAB_ACCEPT_PLINKS : 0x00;
+	/* Mesh PS mode. See IEEE802.11-2012 8.4.2.100.8 */
+	*pos |= ifmsh->ps_peers_deep_sleep ?
+	    IEEE80211_MESHCONF_CAPAB_POWER_SAVE_LEVEL : 0x00;
 	*pos++ |= ifmsh->adjusting_tbtt ?
 	    IEEE80211_MESHCONF_CAPAB_TBTT_ADJUSTING : 0x00;
 	*pos++ = 0x00;
@@ -286,6 +289,29 @@ mesh_add_meshid_ie(struct sk_buff *skb, struct ieee80211_sub_if_data *sdata)
 	return 0;
 }
 
+int mesh_add_awake_window_ie(struct sk_buff *skb,
+			     struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
+	u8 *pos;
+
+	/* see IEEE802.11-2012 13.14.6 */
+	if (ifmsh->ps_peers_light_sleep == 0 &&
+	    ifmsh->ps_peers_deep_sleep == 0 &&
+	    ifmsh->nonpeer_pm == NL80211_MESH_POWER_ACTIVE)
+		return 0;
+
+	if (skb_tailroom(skb) < 4)
+		return -ENOMEM;
+
+	pos = skb_put(skb, 2 + 2);
+	*pos++ = WLAN_EID_MESH_AWAKE_WINDOW;
+	*pos++ = 2;
+	put_unaligned_le16(ifmsh->mshcfg.dot11MeshAwakeWindowDuration, pos);
+
+	return 0;
+}
+
 int
 mesh_add_vendor_ies(struct sk_buff *skb, struct ieee80211_sub_if_data *sdata)
 {
@@ -629,6 +655,8 @@ void ieee80211_start_mesh(struct ieee80211_sub_if_data *sdata)
 	sdata->vif.bss_conf.basic_rates =
 		ieee80211_mandatory_rates(local, band);
 
+	ieee80211_mps_local_status_update(sdata);
+
 	ieee80211_bss_info_change_notify(sdata, changed);
 
 	netif_carrier_on(sdata->dev);
@@ -651,6 +679,10 @@ void ieee80211_stop_mesh(struct ieee80211_sub_if_data *sdata)
 	sta_info_flush(sdata);
 	mesh_path_flush_by_iface(sdata);
 
+	/* free all potentially still buffered group-addressed frames */
+	local->total_ps_buffered -= skb_queue_len(&ifmsh->ps.bc_buf);
+	skb_queue_purge(&ifmsh->ps.bc_buf);
+
 	del_timer_sync(&sdata->u.mesh.housekeeping_timer);
 	del_timer_sync(&sdata->u.mesh.mesh_path_root_timer);
 	del_timer_sync(&sdata->u.mesh.mesh_path_timer);
@@ -828,6 +860,7 @@ void ieee80211_mesh_init_sdata(struct ieee80211_sub_if_data *sdata)
 		    ieee80211_mesh_path_root_timer,
 		    (unsigned long) sdata);
 	INIT_LIST_HEAD(&ifmsh->preq_queue.list);
+	skb_queue_head_init(&ifmsh->ps.bc_buf);
 	spin_lock_init(&ifmsh->mesh_preq_queue_lock);
 	spin_lock_init(&ifmsh->sync_offset_lock);