linux/net/mac80211/sta_info.h

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/*
* Copyright 2002-2005, Devicescape Software, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef STA_INFO_H
#define STA_INFO_H
#include <linux/list.h>
#include <linux/types.h>
#include <linux/if_ether.h>
mac80211: async station powersave handling Some devices require that all frames to a station are flushed when that station goes into powersave mode before being able to send frames to that station again when it wakes up or polls -- all in order to avoid reordering and too many or too few frames being sent to the station when it polls. Normally, this is the case unless the station goes to sleep and wakes up very quickly again. But in that case, frames for it may be pending on the hardware queues, and thus races could happen in the case of multiple hardware queues used for QoS/WMM. Normally this isn't a problem, but with the iwlwifi mechanism we need to make sure the race doesn't happen. This makes mac80211 able to cope with the race with driver help by a new WLAN_STA_PS_DRIVER per-station flag that can be controlled by the driver and tells mac80211 whether it can transmit frames or not. This flag must be set according to very specific rules outlined in the documentation for the function that controls it. When we buffer new frames for the station, we normally set the TIM bit right away, but while the driver has blocked transmission to that sta we need to avoid that as well since we cannot respond to the station if it wakes up due to the TIM bit. Once the driver unblocks, we can set the TIM bit. Similarly, when the station just wakes up, we need to wait until all other frames are flushed before we can transmit frames to that station, so the same applies here, we need to wait for the driver to give the OK. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-06 18:35:50 +08:00
#include <linux/workqueue.h>
#include <linux/average.h>
#include <linux/etherdevice.h>
#include "key.h"
/**
* enum ieee80211_sta_info_flags - Stations flags
*
* These flags are used with &struct sta_info's @flags member, but
* only indirectly with set_sta_flag() and friends.
*
* @WLAN_STA_AUTH: Station is authenticated.
* @WLAN_STA_ASSOC: Station is associated.
mac80211: async station powersave handling Some devices require that all frames to a station are flushed when that station goes into powersave mode before being able to send frames to that station again when it wakes up or polls -- all in order to avoid reordering and too many or too few frames being sent to the station when it polls. Normally, this is the case unless the station goes to sleep and wakes up very quickly again. But in that case, frames for it may be pending on the hardware queues, and thus races could happen in the case of multiple hardware queues used for QoS/WMM. Normally this isn't a problem, but with the iwlwifi mechanism we need to make sure the race doesn't happen. This makes mac80211 able to cope with the race with driver help by a new WLAN_STA_PS_DRIVER per-station flag that can be controlled by the driver and tells mac80211 whether it can transmit frames or not. This flag must be set according to very specific rules outlined in the documentation for the function that controls it. When we buffer new frames for the station, we normally set the TIM bit right away, but while the driver has blocked transmission to that sta we need to avoid that as well since we cannot respond to the station if it wakes up due to the TIM bit. Once the driver unblocks, we can set the TIM bit. Similarly, when the station just wakes up, we need to wait until all other frames are flushed before we can transmit frames to that station, so the same applies here, we need to wait for the driver to give the OK. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-06 18:35:50 +08:00
* @WLAN_STA_PS_STA: Station is in power-save mode
* @WLAN_STA_AUTHORIZED: Station is authorized to send/receive traffic.
* This bit is always checked so needs to be enabled for all stations
* when virtual port control is not in use.
* @WLAN_STA_SHORT_PREAMBLE: Station is capable of receiving short-preamble
* frames.
* @WLAN_STA_WME: Station is a QoS-STA.
* @WLAN_STA_WDS: Station is one of our WDS peers.
* @WLAN_STA_CLEAR_PS_FILT: Clear PS filter in hardware (using the
* IEEE80211_TX_CTL_CLEAR_PS_FILT control flag) when the next
* frame to this station is transmitted.
* @WLAN_STA_MFP: Management frame protection is used with this STA.
* @WLAN_STA_BLOCK_BA: Used to deny ADDBA requests (both TX and RX)
* during suspend/resume and station removal.
mac80211: async station powersave handling Some devices require that all frames to a station are flushed when that station goes into powersave mode before being able to send frames to that station again when it wakes up or polls -- all in order to avoid reordering and too many or too few frames being sent to the station when it polls. Normally, this is the case unless the station goes to sleep and wakes up very quickly again. But in that case, frames for it may be pending on the hardware queues, and thus races could happen in the case of multiple hardware queues used for QoS/WMM. Normally this isn't a problem, but with the iwlwifi mechanism we need to make sure the race doesn't happen. This makes mac80211 able to cope with the race with driver help by a new WLAN_STA_PS_DRIVER per-station flag that can be controlled by the driver and tells mac80211 whether it can transmit frames or not. This flag must be set according to very specific rules outlined in the documentation for the function that controls it. When we buffer new frames for the station, we normally set the TIM bit right away, but while the driver has blocked transmission to that sta we need to avoid that as well since we cannot respond to the station if it wakes up due to the TIM bit. Once the driver unblocks, we can set the TIM bit. Similarly, when the station just wakes up, we need to wait until all other frames are flushed before we can transmit frames to that station, so the same applies here, we need to wait for the driver to give the OK. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-06 18:35:50 +08:00
* @WLAN_STA_PS_DRIVER: driver requires keeping this station in
* power-save mode logically to flush frames that might still
* be in the queues
* @WLAN_STA_PSPOLL: Station sent PS-poll while driver was keeping
* station in power-save mode, reply when the driver unblocks.
* @WLAN_STA_TDLS_PEER: Station is a TDLS peer.
* @WLAN_STA_TDLS_PEER_AUTH: This TDLS peer is authorized to send direct
* packets. This means the link is enabled.
* @WLAN_STA_UAPSD: Station requested unscheduled SP while driver was
* keeping station in power-save mode, reply when the driver
* unblocks the station.
* @WLAN_STA_SP: Station is in a service period, so don't try to
* reply to other uAPSD trigger frames or PS-Poll.
* @WLAN_STA_4ADDR_EVENT: 4-addr event was already sent for this frame.
* @WLAN_STA_INSERTED: This station is inserted into the hash table.
* @WLAN_STA_RATE_CONTROL: rate control was initialized for this station.
* @WLAN_STA_TOFFSET_KNOWN: toffset calculated for this station is valid.
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>
2013-01-31 01:14:08 +08:00
* @WLAN_STA_MPSP_OWNER: local STA is owner of a mesh Peer Service Period.
* @WLAN_STA_MPSP_RECIPIENT: local STA is recipient of a MPSP.
*/
enum ieee80211_sta_info_flags {
WLAN_STA_AUTH,
WLAN_STA_ASSOC,
WLAN_STA_PS_STA,
WLAN_STA_AUTHORIZED,
WLAN_STA_SHORT_PREAMBLE,
WLAN_STA_WME,
WLAN_STA_WDS,
WLAN_STA_CLEAR_PS_FILT,
WLAN_STA_MFP,
WLAN_STA_BLOCK_BA,
WLAN_STA_PS_DRIVER,
WLAN_STA_PSPOLL,
WLAN_STA_TDLS_PEER,
WLAN_STA_TDLS_PEER_AUTH,
WLAN_STA_UAPSD,
WLAN_STA_SP,
WLAN_STA_4ADDR_EVENT,
WLAN_STA_INSERTED,
WLAN_STA_RATE_CONTROL,
WLAN_STA_TOFFSET_KNOWN,
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>
2013-01-31 01:14:08 +08:00
WLAN_STA_MPSP_OWNER,
WLAN_STA_MPSP_RECIPIENT,
};
#define ADDBA_RESP_INTERVAL HZ
#define HT_AGG_MAX_RETRIES 15
#define HT_AGG_BURST_RETRIES 3
#define HT_AGG_RETRIES_PERIOD (15 * HZ)
#define HT_AGG_STATE_DRV_READY 0
#define HT_AGG_STATE_RESPONSE_RECEIVED 1
#define HT_AGG_STATE_OPERATIONAL 2
#define HT_AGG_STATE_STOPPING 3
#define HT_AGG_STATE_WANT_START 4
#define HT_AGG_STATE_WANT_STOP 5
enum ieee80211_agg_stop_reason {
AGG_STOP_DECLINED,
AGG_STOP_LOCAL_REQUEST,
AGG_STOP_PEER_REQUEST,
AGG_STOP_DESTROY_STA,
};
/**
* struct tid_ampdu_tx - TID aggregation information (Tx).
*
* @rcu_head: rcu head for freeing structure
* @session_timer: check if we keep Tx-ing on the TID (by timeout value)
* @addba_resp_timer: timer for peer's response to addba request
* @pending: pending frames queue -- use sta's spinlock to protect
* @dialog_token: dialog token for aggregation session
* @timeout: session timeout value to be filled in ADDBA requests
* @state: session state (see above)
* @last_tx: jiffies of last tx activity
* @stop_initiator: initiator of a session stop
* @tx_stop: TX DelBA frame when stopping
* @buf_size: reorder buffer size at receiver
* @failed_bar_ssn: ssn of the last failed BAR tx attempt
* @bar_pending: BAR needs to be re-sent
*
* This structure's lifetime is managed by RCU, assignments to
* the array holding it must hold the aggregation mutex.
*
* The TX path can access it under RCU lock-free if, and
* only if, the state has the flag %HT_AGG_STATE_OPERATIONAL
* set. Otherwise, the TX path must also acquire the spinlock
* and re-check the state, see comments in the tx code
* touching it.
*/
struct tid_ampdu_tx {
struct rcu_head rcu_head;
struct timer_list session_timer;
struct timer_list addba_resp_timer;
struct sk_buff_head pending;
unsigned long state;
unsigned long last_tx;
u16 timeout;
u8 dialog_token;
u8 stop_initiator;
bool tx_stop;
u8 buf_size;
u16 failed_bar_ssn;
bool bar_pending;
};
/**
* struct tid_ampdu_rx - TID aggregation information (Rx).
*
* @reorder_buf: buffer to reorder incoming aggregated MPDUs
* @reorder_time: jiffies when skb was added
* @session_timer: check if peer keeps Tx-ing on the TID (by timeout value)
* @reorder_timer: releases expired frames from the reorder buffer.
* @last_rx: jiffies of last rx activity
* @head_seq_num: head sequence number in reordering buffer.
* @stored_mpdu_num: number of MPDUs in reordering buffer
* @ssn: Starting Sequence Number expected to be aggregated.
* @buf_size: buffer size for incoming A-MPDUs
* @timeout: reset timer value (in TUs).
* @dialog_token: dialog token for aggregation session
* @rcu_head: RCU head used for freeing this struct
* @reorder_lock: serializes access to reorder buffer, see below.
*
* This structure's lifetime is managed by RCU, assignments to
* the array holding it must hold the aggregation mutex.
*
* The @reorder_lock is used to protect the members of this
* struct, except for @timeout, @buf_size and @dialog_token,
* which are constant across the lifetime of the struct (the
* dialog token being used only for debugging).
*/
struct tid_ampdu_rx {
struct rcu_head rcu_head;
spinlock_t reorder_lock;
struct sk_buff **reorder_buf;
unsigned long *reorder_time;
struct timer_list session_timer;
struct timer_list reorder_timer;
unsigned long last_rx;
u16 head_seq_num;
u16 stored_mpdu_num;
u16 ssn;
u16 buf_size;
u16 timeout;
u8 dialog_token;
};
/**
* struct sta_ampdu_mlme - STA aggregation information.
*
* @tid_rx: aggregation info for Rx per TID -- RCU protected
* @tid_tx: aggregation info for Tx per TID
* @tid_start_tx: sessions where start was requested
* @addba_req_num: number of times addBA request has been sent.
* @last_addba_req_time: timestamp of the last addBA request.
* @dialog_token_allocator: dialog token enumerator for each new session;
* @work: work struct for starting/stopping aggregation
* @tid_rx_timer_expired: bitmap indicating on which TIDs the
* RX timer expired until the work for it runs
* @tid_rx_stop_requested: bitmap indicating which BA sessions per TID the
* driver requested to close until the work for it runs
* @mtx: mutex to protect all TX data (except non-NULL assignments
* to tid_tx[idx], which are protected by the sta spinlock)
* tid_start_tx is also protected by sta->lock.
*/
struct sta_ampdu_mlme {
struct mutex mtx;
/* rx */
struct tid_ampdu_rx __rcu *tid_rx[IEEE80211_NUM_TIDS];
unsigned long tid_rx_timer_expired[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];
unsigned long tid_rx_stop_requested[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];
/* tx */
struct work_struct work;
struct tid_ampdu_tx __rcu *tid_tx[IEEE80211_NUM_TIDS];
struct tid_ampdu_tx *tid_start_tx[IEEE80211_NUM_TIDS];
unsigned long last_addba_req_time[IEEE80211_NUM_TIDS];
u8 addba_req_num[IEEE80211_NUM_TIDS];
u8 dialog_token_allocator;
};
/*
* struct ieee80211_tx_latency_stat - Tx latency statistics
*
* Measures TX latency and jitter for a station per TID.
*
* @max: worst case latency
* @sum: sum of all latencies
* @counter: amount of Tx frames sent from interface
* @bins: each bin counts how many frames transmitted within a certain
* latency range. when disabled it is NULL.
* @bin_count: amount of bins.
*/
struct ieee80211_tx_latency_stat {
u32 max;
u32 sum;
u32 counter;
u32 *bins;
u32 bin_count;
};
/**
* struct sta_info - STA information
*
* This structure collects information about a station that
* mac80211 is communicating with.
*
* @list: global linked list entry
* @free_list: list entry for keeping track of stations to free
* @hnext: hash table linked list pointer
* @local: pointer to the global information
* @sdata: virtual interface this station belongs to
* @ptk: peer keys negotiated with this station, if any
* @ptk_idx: last installed peer key index
* @gtk: group keys negotiated with this station, if any
* @gtk_idx: last installed group key index
* @rate_ctrl: rate control algorithm reference
* @rate_ctrl_priv: rate control private per-STA pointer
* @last_tx_rate: rate used for last transmit, to report to userspace as
* "the" transmit rate
* @last_rx_rate_idx: rx status rate index of the last data packet
* @last_rx_rate_flag: rx status flag of the last data packet
* @last_rx_rate_vht_flag: rx status vht flag of the last data packet
* @last_rx_rate_vht_nss: rx status nss of last data packet
* @lock: used for locking all fields that require locking, see comments
* in the header file.
* @drv_unblock_wk: used for driver PS unblocking
* @listen_interval: listen interval of this station, when we're acting as AP
* @_flags: STA flags, see &enum ieee80211_sta_info_flags, do not use directly
mac80211: fix AP powersave TX vs. wakeup race There is a race between the TX path and the STA wakeup: while a station is sleeping, mac80211 buffers frames until it wakes up, then the frames are transmitted. However, the RX and TX path are concurrent, so the packet indicating wakeup can be processed while a packet is being transmitted. This can lead to a situation where the buffered frames list is emptied on the one side, while a frame is being added on the other side, as the station is still seen as sleeping in the TX path. As a result, the newly added frame will not be send anytime soon. It might be sent much later (and out of order) when the station goes to sleep and wakes up the next time. Additionally, it can lead to the crash below. Fix all this by synchronising both paths with a new lock. Both path are not fastpath since they handle PS situations. In a later patch we'll remove the extra skb queue locks to reduce locking overhead. BUG: unable to handle kernel NULL pointer dereference at 000000b0 IP: [<ff6f1791>] ieee80211_report_used_skb+0x11/0x3e0 [mac80211] *pde = 00000000 Oops: 0000 [#1] SMP DEBUG_PAGEALLOC EIP: 0060:[<ff6f1791>] EFLAGS: 00210282 CPU: 1 EIP is at ieee80211_report_used_skb+0x11/0x3e0 [mac80211] EAX: e5900da0 EBX: 00000000 ECX: 00000001 EDX: 00000000 ESI: e41d00c0 EDI: e5900da0 EBP: ebe458e4 ESP: ebe458b0 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 CR0: 8005003b CR2: 000000b0 CR3: 25a78000 CR4: 000407d0 DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 DR6: ffff0ff0 DR7: 00000400 Process iperf (pid: 3934, ti=ebe44000 task=e757c0b0 task.ti=ebe44000) iwlwifi 0000:02:00.0: I iwl_pcie_enqueue_hcmd Sending command LQ_CMD (#4e), seq: 0x0903, 92 bytes at 3[3]:9 Stack: e403b32c ebe458c4 00200002 00200286 e403b338 ebe458cc c10960bb e5900da0 ff76a6ec ebe458d8 00000000 e41d00c0 e5900da0 ebe458f0 ff6f1b75 e403b210 ebe4598c ff723dc1 00000000 ff76a6ec e597c978 e403b758 00000002 00000002 Call Trace: [<ff6f1b75>] ieee80211_free_txskb+0x15/0x20 [mac80211] [<ff723dc1>] invoke_tx_handlers+0x1661/0x1780 [mac80211] [<ff7248a5>] ieee80211_tx+0x75/0x100 [mac80211] [<ff7249bf>] ieee80211_xmit+0x8f/0xc0 [mac80211] [<ff72550e>] ieee80211_subif_start_xmit+0x4fe/0xe20 [mac80211] [<c149ef70>] dev_hard_start_xmit+0x450/0x950 [<c14b9aa9>] sch_direct_xmit+0xa9/0x250 [<c14b9c9b>] __qdisc_run+0x4b/0x150 [<c149f732>] dev_queue_xmit+0x2c2/0xca0 Cc: stable@vger.kernel.org Reported-by: Yaara Rozenblum <yaara.rozenblum@intel.com> Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com> Reviewed-by: Stanislaw Gruszka <sgruszka@redhat.com> [reword commit log, use a separate lock] Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2014-02-20 15:22:11 +08:00
* @ps_lock: used for powersave (when mac80211 is the AP) related locking
* @ps_tx_buf: buffers (per AC) of frames to transmit to this station
* when it leaves power saving state or polls
* @tx_filtered: buffers (per AC) of frames we already tried to
* transmit but were filtered by hardware due to STA having
* entered power saving state, these are also delivered to
* the station when it leaves powersave or polls for frames
* @driver_buffered_tids: bitmap of TIDs the driver has data buffered on
* @rx_packets: Number of MSDUs received from this STA
* @rx_bytes: Number of bytes received from this STA
* @wep_weak_iv_count: number of weak WEP IVs received from this station
* @last_rx: time (in jiffies) when last frame was received from this STA
* @last_connected: time (in seconds) when a station got connected
* @num_duplicates: number of duplicate frames received from this STA
* @rx_fragments: number of received MPDUs
* @rx_dropped: number of dropped MPDUs from this STA
* @last_signal: signal of last received frame from this STA
* @avg_signal: moving average of signal of received frames from this STA
* @last_ack_signal: signal of last received Ack frame from this STA
* @last_seq_ctrl: last received seq/frag number from this STA (per RX queue)
* @tx_filtered_count: number of frames the hardware filtered for this STA
* @tx_retry_failed: number of frames that failed retry
* @tx_retry_count: total number of retries for frames to this STA
* @fail_avg: moving percentage of failed MSDUs
* @tx_packets: number of RX/TX MSDUs
* @tx_bytes: number of bytes transmitted to this STA
* @tx_fragments: number of transmitted MPDUs
* @tid_seq: per-TID sequence numbers for sending to this STA
* @ampdu_mlme: A-MPDU state machine state
* @timer_to_tid: identity mapping to ID timers
* @tx_lat: Tx latency statistics
* @llid: Local link ID
* @plid: Peer link ID
* @reason: Cancel reason on PLINK_HOLDING state
* @plink_retries: Retries in establishment
* @ignore_plink_timer: ignore the peer-link timer (used internally)
* @plink_state: peer link state
* @plink_timeout: timeout of peer link
* @plink_timer: peer link watch timer
* @t_offset: timing offset relative to this host
* @t_offset_setpoint: reference timing offset of this sta to be used when
* calculating clockdrift
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>
2013-01-31 01:14:08 +08:00
* @local_pm: local link-specific power save mode
* @peer_pm: peer-specific power save mode towards local STA
* @nonpeer_pm: STA power save mode towards non-peer neighbors
* @debugfs: debug filesystem info
mac80211: async station powersave handling Some devices require that all frames to a station are flushed when that station goes into powersave mode before being able to send frames to that station again when it wakes up or polls -- all in order to avoid reordering and too many or too few frames being sent to the station when it polls. Normally, this is the case unless the station goes to sleep and wakes up very quickly again. But in that case, frames for it may be pending on the hardware queues, and thus races could happen in the case of multiple hardware queues used for QoS/WMM. Normally this isn't a problem, but with the iwlwifi mechanism we need to make sure the race doesn't happen. This makes mac80211 able to cope with the race with driver help by a new WLAN_STA_PS_DRIVER per-station flag that can be controlled by the driver and tells mac80211 whether it can transmit frames or not. This flag must be set according to very specific rules outlined in the documentation for the function that controls it. When we buffer new frames for the station, we normally set the TIM bit right away, but while the driver has blocked transmission to that sta we need to avoid that as well since we cannot respond to the station if it wakes up due to the TIM bit. Once the driver unblocks, we can set the TIM bit. Similarly, when the station just wakes up, we need to wait until all other frames are flushed before we can transmit frames to that station, so the same applies here, we need to wait for the driver to give the OK. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-06 18:35:50 +08:00
* @dead: set to true when sta is unlinked
* @uploaded: set to true when sta is uploaded to the driver
* @lost_packets: number of consecutive lost packets
* @sta: station information we share with the driver
* @sta_state: duplicates information about station state (for debug)
* @beacon_loss_count: number of times beacon loss has triggered
* @rcu_head: RCU head used for freeing this station struct
* @cur_max_bandwidth: maximum bandwidth to use for TX to the station,
* taken from HT/VHT capabilities or VHT operating mode notification
* @chains: chains ever used for RX from this station
* @chain_signal_last: last signal (per chain)
* @chain_signal_avg: signal average (per chain)
* @known_smps_mode: the smps_mode the client thinks we are in. Relevant for
* AP only.
* @cipher_scheme: optional cipher scheme for this station
*/
struct sta_info {
/* General information, mostly static */
struct list_head list, free_list;
struct rcu_head rcu_head;
struct sta_info __rcu *hnext;
struct ieee80211_local *local;
struct ieee80211_sub_if_data *sdata;
struct ieee80211_key __rcu *gtk[NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS];
struct ieee80211_key __rcu *ptk[NUM_DEFAULT_KEYS];
u8 gtk_idx;
u8 ptk_idx;
struct rate_control_ref *rate_ctrl;
void *rate_ctrl_priv;
spinlock_t lock;
mac80211: async station powersave handling Some devices require that all frames to a station are flushed when that station goes into powersave mode before being able to send frames to that station again when it wakes up or polls -- all in order to avoid reordering and too many or too few frames being sent to the station when it polls. Normally, this is the case unless the station goes to sleep and wakes up very quickly again. But in that case, frames for it may be pending on the hardware queues, and thus races could happen in the case of multiple hardware queues used for QoS/WMM. Normally this isn't a problem, but with the iwlwifi mechanism we need to make sure the race doesn't happen. This makes mac80211 able to cope with the race with driver help by a new WLAN_STA_PS_DRIVER per-station flag that can be controlled by the driver and tells mac80211 whether it can transmit frames or not. This flag must be set according to very specific rules outlined in the documentation for the function that controls it. When we buffer new frames for the station, we normally set the TIM bit right away, but while the driver has blocked transmission to that sta we need to avoid that as well since we cannot respond to the station if it wakes up due to the TIM bit. Once the driver unblocks, we can set the TIM bit. Similarly, when the station just wakes up, we need to wait until all other frames are flushed before we can transmit frames to that station, so the same applies here, we need to wait for the driver to give the OK. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-06 18:35:50 +08:00
struct work_struct drv_unblock_wk;
u16 listen_interval;
mac80211: async station powersave handling Some devices require that all frames to a station are flushed when that station goes into powersave mode before being able to send frames to that station again when it wakes up or polls -- all in order to avoid reordering and too many or too few frames being sent to the station when it polls. Normally, this is the case unless the station goes to sleep and wakes up very quickly again. But in that case, frames for it may be pending on the hardware queues, and thus races could happen in the case of multiple hardware queues used for QoS/WMM. Normally this isn't a problem, but with the iwlwifi mechanism we need to make sure the race doesn't happen. This makes mac80211 able to cope with the race with driver help by a new WLAN_STA_PS_DRIVER per-station flag that can be controlled by the driver and tells mac80211 whether it can transmit frames or not. This flag must be set according to very specific rules outlined in the documentation for the function that controls it. When we buffer new frames for the station, we normally set the TIM bit right away, but while the driver has blocked transmission to that sta we need to avoid that as well since we cannot respond to the station if it wakes up due to the TIM bit. Once the driver unblocks, we can set the TIM bit. Similarly, when the station just wakes up, we need to wait until all other frames are flushed before we can transmit frames to that station, so the same applies here, we need to wait for the driver to give the OK. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-06 18:35:50 +08:00
bool dead;
bool uploaded;
enum ieee80211_sta_state sta_state;
/* use the accessors defined below */
unsigned long _flags;
mac80211: fix AP powersave TX vs. wakeup race There is a race between the TX path and the STA wakeup: while a station is sleeping, mac80211 buffers frames until it wakes up, then the frames are transmitted. However, the RX and TX path are concurrent, so the packet indicating wakeup can be processed while a packet is being transmitted. This can lead to a situation where the buffered frames list is emptied on the one side, while a frame is being added on the other side, as the station is still seen as sleeping in the TX path. As a result, the newly added frame will not be send anytime soon. It might be sent much later (and out of order) when the station goes to sleep and wakes up the next time. Additionally, it can lead to the crash below. Fix all this by synchronising both paths with a new lock. Both path are not fastpath since they handle PS situations. In a later patch we'll remove the extra skb queue locks to reduce locking overhead. BUG: unable to handle kernel NULL pointer dereference at 000000b0 IP: [<ff6f1791>] ieee80211_report_used_skb+0x11/0x3e0 [mac80211] *pde = 00000000 Oops: 0000 [#1] SMP DEBUG_PAGEALLOC EIP: 0060:[<ff6f1791>] EFLAGS: 00210282 CPU: 1 EIP is at ieee80211_report_used_skb+0x11/0x3e0 [mac80211] EAX: e5900da0 EBX: 00000000 ECX: 00000001 EDX: 00000000 ESI: e41d00c0 EDI: e5900da0 EBP: ebe458e4 ESP: ebe458b0 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 CR0: 8005003b CR2: 000000b0 CR3: 25a78000 CR4: 000407d0 DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 DR6: ffff0ff0 DR7: 00000400 Process iperf (pid: 3934, ti=ebe44000 task=e757c0b0 task.ti=ebe44000) iwlwifi 0000:02:00.0: I iwl_pcie_enqueue_hcmd Sending command LQ_CMD (#4e), seq: 0x0903, 92 bytes at 3[3]:9 Stack: e403b32c ebe458c4 00200002 00200286 e403b338 ebe458cc c10960bb e5900da0 ff76a6ec ebe458d8 00000000 e41d00c0 e5900da0 ebe458f0 ff6f1b75 e403b210 ebe4598c ff723dc1 00000000 ff76a6ec e597c978 e403b758 00000002 00000002 Call Trace: [<ff6f1b75>] ieee80211_free_txskb+0x15/0x20 [mac80211] [<ff723dc1>] invoke_tx_handlers+0x1661/0x1780 [mac80211] [<ff7248a5>] ieee80211_tx+0x75/0x100 [mac80211] [<ff7249bf>] ieee80211_xmit+0x8f/0xc0 [mac80211] [<ff72550e>] ieee80211_subif_start_xmit+0x4fe/0xe20 [mac80211] [<c149ef70>] dev_hard_start_xmit+0x450/0x950 [<c14b9aa9>] sch_direct_xmit+0xa9/0x250 [<c14b9c9b>] __qdisc_run+0x4b/0x150 [<c149f732>] dev_queue_xmit+0x2c2/0xca0 Cc: stable@vger.kernel.org Reported-by: Yaara Rozenblum <yaara.rozenblum@intel.com> Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com> Reviewed-by: Stanislaw Gruszka <sgruszka@redhat.com> [reword commit log, use a separate lock] Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2014-02-20 15:22:11 +08:00
/* STA powersave lock and frame queues */
spinlock_t ps_lock;
struct sk_buff_head ps_tx_buf[IEEE80211_NUM_ACS];
struct sk_buff_head tx_filtered[IEEE80211_NUM_ACS];
unsigned long driver_buffered_tids;
/* Updated from RX path only, no locking requirements */
unsigned long rx_packets;
u64 rx_bytes;
unsigned long wep_weak_iv_count;
unsigned long last_rx;
long last_connected;
unsigned long num_duplicates;
unsigned long rx_fragments;
unsigned long rx_dropped;
int last_signal;
struct ewma avg_signal;
int last_ack_signal;
u8 chains;
s8 chain_signal_last[IEEE80211_MAX_CHAINS];
struct ewma chain_signal_avg[IEEE80211_MAX_CHAINS];
/* Plus 1 for non-QoS frames */
__le16 last_seq_ctrl[IEEE80211_NUM_TIDS + 1];
/* Updated from TX status path only, no locking requirements */
unsigned long tx_filtered_count;
unsigned long tx_retry_failed, tx_retry_count;
/* moving percentage of failed MSDUs */
unsigned int fail_avg;
/* Updated from TX path only, no locking requirements */
u32 tx_fragments;
u64 tx_packets[IEEE80211_NUM_ACS];
u64 tx_bytes[IEEE80211_NUM_ACS];
struct ieee80211_tx_rate last_tx_rate;
int last_rx_rate_idx;
u32 last_rx_rate_flag;
u32 last_rx_rate_vht_flag;
u8 last_rx_rate_vht_nss;
u16 tid_seq[IEEE80211_QOS_CTL_TID_MASK + 1];
/*
* Aggregation information, locked with lock.
*/
struct sta_ampdu_mlme ampdu_mlme;
u8 timer_to_tid[IEEE80211_NUM_TIDS];
struct ieee80211_tx_latency_stat *tx_lat;
#ifdef CONFIG_MAC80211_MESH
/*
* Mesh peer link attributes
* TODO: move to a sub-structure that is referenced with pointer?
*/
u16 llid;
u16 plid;
u16 reason;
u8 plink_retries;
bool ignore_plink_timer;
enum nl80211_plink_state plink_state;
u32 plink_timeout;
struct timer_list plink_timer;
s64 t_offset;
s64 t_offset_setpoint;
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>
2013-01-31 01:14:08 +08:00
/* mesh power save */
enum nl80211_mesh_power_mode local_pm;
enum nl80211_mesh_power_mode peer_pm;
enum nl80211_mesh_power_mode nonpeer_pm;
#endif
#ifdef CONFIG_MAC80211_DEBUGFS
struct sta_info_debugfsdentries {
struct dentry *dir;
bool add_has_run;
} debugfs;
#endif
enum ieee80211_sta_rx_bandwidth cur_max_bandwidth;
unsigned int lost_packets;
unsigned int beacon_loss_count;
enum ieee80211_smps_mode known_smps_mode;
const struct ieee80211_cipher_scheme *cipher_scheme;
/* keep last! */
struct ieee80211_sta sta;
};
static inline enum nl80211_plink_state sta_plink_state(struct sta_info *sta)
{
#ifdef CONFIG_MAC80211_MESH
return sta->plink_state;
#endif
return NL80211_PLINK_LISTEN;
}
static inline void set_sta_flag(struct sta_info *sta,
enum ieee80211_sta_info_flags flag)
{
WARN_ON(flag == WLAN_STA_AUTH ||
flag == WLAN_STA_ASSOC ||
flag == WLAN_STA_AUTHORIZED);
set_bit(flag, &sta->_flags);
}
static inline void clear_sta_flag(struct sta_info *sta,
enum ieee80211_sta_info_flags flag)
{
WARN_ON(flag == WLAN_STA_AUTH ||
flag == WLAN_STA_ASSOC ||
flag == WLAN_STA_AUTHORIZED);
clear_bit(flag, &sta->_flags);
}
static inline int test_sta_flag(struct sta_info *sta,
enum ieee80211_sta_info_flags flag)
{
return test_bit(flag, &sta->_flags);
}
static inline int test_and_clear_sta_flag(struct sta_info *sta,
enum ieee80211_sta_info_flags flag)
{
WARN_ON(flag == WLAN_STA_AUTH ||
flag == WLAN_STA_ASSOC ||
flag == WLAN_STA_AUTHORIZED);
return test_and_clear_bit(flag, &sta->_flags);
}
static inline int test_and_set_sta_flag(struct sta_info *sta,
enum ieee80211_sta_info_flags flag)
{
WARN_ON(flag == WLAN_STA_AUTH ||
flag == WLAN_STA_ASSOC ||
flag == WLAN_STA_AUTHORIZED);
return test_and_set_bit(flag, &sta->_flags);
}
int sta_info_move_state(struct sta_info *sta,
enum ieee80211_sta_state new_state);
static inline void sta_info_pre_move_state(struct sta_info *sta,
enum ieee80211_sta_state new_state)
{
int ret;
WARN_ON_ONCE(test_sta_flag(sta, WLAN_STA_INSERTED));
ret = sta_info_move_state(sta, new_state);
WARN_ON_ONCE(ret);
}
void ieee80211_assign_tid_tx(struct sta_info *sta, int tid,
struct tid_ampdu_tx *tid_tx);
static inline struct tid_ampdu_tx *
rcu_dereference_protected_tid_tx(struct sta_info *sta, int tid)
{
return rcu_dereference_protected(sta->ampdu_mlme.tid_tx[tid],
lockdep_is_held(&sta->lock) ||
lockdep_is_held(&sta->ampdu_mlme.mtx));
}
#define STA_HASH_SIZE 256
#define STA_HASH(sta) (sta[5])
/* Maximum number of frames to buffer per power saving station per AC */
#define STA_MAX_TX_BUFFER 64
/* Minimum buffered frame expiry time. If STA uses listen interval that is
* smaller than this value, the minimum value here is used instead. */
#define STA_TX_BUFFER_EXPIRE (10 * HZ)
/* How often station data is cleaned up (e.g., expiration of buffered frames)
*/
#define STA_INFO_CLEANUP_INTERVAL (10 * HZ)
/*
* Get a STA info, must be under RCU read lock.
*/
struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
const u8 *addr);
struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
const u8 *addr);
static inline
void for_each_sta_info_type_check(struct ieee80211_local *local,
const u8 *addr,
struct sta_info *sta,
struct sta_info *nxt)
{
}
#define for_each_sta_info(local, _addr, _sta, nxt) \
for ( /* initialise loop */ \
_sta = rcu_dereference(local->sta_hash[STA_HASH(_addr)]),\
nxt = _sta ? rcu_dereference(_sta->hnext) : NULL; \
/* typecheck */ \
for_each_sta_info_type_check(local, (_addr), _sta, nxt),\
/* continue condition */ \
_sta; \
/* advance loop */ \
_sta = nxt, \
nxt = _sta ? rcu_dereference(_sta->hnext) : NULL \
) \
/* compare address and run code only if it matches */ \
if (ether_addr_equal(_sta->sta.addr, (_addr)))
/*
* Get STA info by index, BROKEN!
*/
struct sta_info *sta_info_get_by_idx(struct ieee80211_sub_if_data *sdata,
int idx);
/*
* Create a new STA info, caller owns returned structure
* until sta_info_insert().
*/
struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
const u8 *addr, gfp_t gfp);
void sta_info_free(struct ieee80211_local *local, struct sta_info *sta);
/*
* Insert STA info into hash table/list, returns zero or a
* -EEXIST if (if the same MAC address is already present).
*
* Calling the non-rcu version makes the caller relinquish,
* the _rcu version calls read_lock_rcu() and must be called
* without it held.
*/
int sta_info_insert(struct sta_info *sta);
int sta_info_insert_rcu(struct sta_info *sta) __acquires(RCU);
int __must_check __sta_info_destroy(struct sta_info *sta);
int sta_info_destroy_addr(struct ieee80211_sub_if_data *sdata,
const u8 *addr);
int sta_info_destroy_addr_bss(struct ieee80211_sub_if_data *sdata,
const u8 *addr);
void sta_info_recalc_tim(struct sta_info *sta);
void sta_info_init(struct ieee80211_local *local);
void sta_info_stop(struct ieee80211_local *local);
/**
* sta_info_flush - flush matching STA entries from the STA table
*
* Returns the number of removed STA entries.
*
* @sdata: sdata to remove all stations from
* @vlans: if the given interface is an AP interface, also flush VLANs
*/
int __sta_info_flush(struct ieee80211_sub_if_data *sdata, bool vlans);
static inline int sta_info_flush(struct ieee80211_sub_if_data *sdata)
{
return __sta_info_flush(sdata, false);
}
void sta_set_rate_info_tx(struct sta_info *sta,
const struct ieee80211_tx_rate *rate,
struct rate_info *rinfo);
void sta_set_rate_info_rx(struct sta_info *sta,
struct rate_info *rinfo);
void ieee80211_sta_expire(struct ieee80211_sub_if_data *sdata,
unsigned long exp_time);
u8 sta_info_tx_streams(struct sta_info *sta);
mac80211: async station powersave handling Some devices require that all frames to a station are flushed when that station goes into powersave mode before being able to send frames to that station again when it wakes up or polls -- all in order to avoid reordering and too many or too few frames being sent to the station when it polls. Normally, this is the case unless the station goes to sleep and wakes up very quickly again. But in that case, frames for it may be pending on the hardware queues, and thus races could happen in the case of multiple hardware queues used for QoS/WMM. Normally this isn't a problem, but with the iwlwifi mechanism we need to make sure the race doesn't happen. This makes mac80211 able to cope with the race with driver help by a new WLAN_STA_PS_DRIVER per-station flag that can be controlled by the driver and tells mac80211 whether it can transmit frames or not. This flag must be set according to very specific rules outlined in the documentation for the function that controls it. When we buffer new frames for the station, we normally set the TIM bit right away, but while the driver has blocked transmission to that sta we need to avoid that as well since we cannot respond to the station if it wakes up due to the TIM bit. Once the driver unblocks, we can set the TIM bit. Similarly, when the station just wakes up, we need to wait until all other frames are flushed before we can transmit frames to that station, so the same applies here, we need to wait for the driver to give the OK. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-06 18:35:50 +08:00
void ieee80211_sta_ps_deliver_wakeup(struct sta_info *sta);
void ieee80211_sta_ps_deliver_poll_response(struct sta_info *sta);
void ieee80211_sta_ps_deliver_uapsd(struct sta_info *sta);
mac80211: async station powersave handling Some devices require that all frames to a station are flushed when that station goes into powersave mode before being able to send frames to that station again when it wakes up or polls -- all in order to avoid reordering and too many or too few frames being sent to the station when it polls. Normally, this is the case unless the station goes to sleep and wakes up very quickly again. But in that case, frames for it may be pending on the hardware queues, and thus races could happen in the case of multiple hardware queues used for QoS/WMM. Normally this isn't a problem, but with the iwlwifi mechanism we need to make sure the race doesn't happen. This makes mac80211 able to cope with the race with driver help by a new WLAN_STA_PS_DRIVER per-station flag that can be controlled by the driver and tells mac80211 whether it can transmit frames or not. This flag must be set according to very specific rules outlined in the documentation for the function that controls it. When we buffer new frames for the station, we normally set the TIM bit right away, but while the driver has blocked transmission to that sta we need to avoid that as well since we cannot respond to the station if it wakes up due to the TIM bit. Once the driver unblocks, we can set the TIM bit. Similarly, when the station just wakes up, we need to wait until all other frames are flushed before we can transmit frames to that station, so the same applies here, we need to wait for the driver to give the OK. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-06 18:35:50 +08:00
#endif /* STA_INFO_H */