linux/net/mac80211/agg-rx.c
Christian Lamparter 2bff8ebf32 mac80211: AMPDU rx reorder timeout timer
This patch introduces a new timer, which will release
queued-up MPDUs from the reorder buffer, whenever
they've waited for more than HT_RX_REORDER_BUF_TIMEOUT
(which is at around 100 ms).

The advantage of having a dedicated timer, instead of
relying on a constant stream of freshly arriving aMPDUs
to release the old ones, is particularly observable when
even a small fraction of MPDUs are forever lost at
low network speeds.

Previously under these circumstances frames would become
stuck in the reorder buffer and the network stack of both
HT peers throttled back, instead of revving up and
gunning the pipes.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-16 15:26:39 -04:00

333 lines
10 KiB
C

/*
* HT handling
*
* Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
* Copyright 2002-2005, Instant802 Networks, Inc.
* Copyright 2005-2006, Devicescape Software, Inc.
* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
* Copyright 2007, Michael Wu <flamingice@sourmilk.net>
* Copyright 2007-2010, Intel Corporation
*
* 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.
*/
/**
* DOC: RX A-MPDU aggregation
*
* Aggregation on the RX side requires only implementing the
* @ampdu_action callback that is invoked to start/stop any
* block-ack sessions for RX aggregation.
*
* When RX aggregation is started by the peer, the driver is
* notified via @ampdu_action function, with the
* %IEEE80211_AMPDU_RX_START action, and may reject the request
* in which case a negative response is sent to the peer, if it
* accepts it a positive response is sent.
*
* While the session is active, the device/driver are required
* to de-aggregate frames and pass them up one by one to mac80211,
* which will handle the reorder buffer.
*
* When the aggregation session is stopped again by the peer or
* ourselves, the driver's @ampdu_action function will be called
* with the action %IEEE80211_AMPDU_RX_STOP. In this case, the
* call must not fail.
*/
#include <linux/ieee80211.h>
#include <linux/slab.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "driver-ops.h"
static void ieee80211_free_tid_rx(struct rcu_head *h)
{
struct tid_ampdu_rx *tid_rx =
container_of(h, struct tid_ampdu_rx, rcu_head);
int i;
for (i = 0; i < tid_rx->buf_size; i++)
dev_kfree_skb(tid_rx->reorder_buf[i]);
kfree(tid_rx->reorder_buf);
kfree(tid_rx->reorder_time);
kfree(tid_rx);
}
void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
u16 initiator, u16 reason)
{
struct ieee80211_local *local = sta->local;
struct tid_ampdu_rx *tid_rx;
lockdep_assert_held(&sta->ampdu_mlme.mtx);
tid_rx = sta->ampdu_mlme.tid_rx[tid];
if (!tid_rx)
return;
rcu_assign_pointer(sta->ampdu_mlme.tid_rx[tid], NULL);
#ifdef CONFIG_MAC80211_HT_DEBUG
printk(KERN_DEBUG "Rx BA session stop requested for %pM tid %u\n",
sta->sta.addr, tid);
#endif /* CONFIG_MAC80211_HT_DEBUG */
if (drv_ampdu_action(local, sta->sdata, IEEE80211_AMPDU_RX_STOP,
&sta->sta, tid, NULL))
printk(KERN_DEBUG "HW problem - can not stop rx "
"aggregation for tid %d\n", tid);
/* check if this is a self generated aggregation halt */
if (initiator == WLAN_BACK_RECIPIENT)
ieee80211_send_delba(sta->sdata, sta->sta.addr,
tid, 0, reason);
del_timer_sync(&tid_rx->session_timer);
del_timer_sync(&tid_rx->reorder_timer);
call_rcu(&tid_rx->rcu_head, ieee80211_free_tid_rx);
}
void __ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
u16 initiator, u16 reason)
{
mutex_lock(&sta->ampdu_mlme.mtx);
___ieee80211_stop_rx_ba_session(sta, tid, initiator, reason);
mutex_unlock(&sta->ampdu_mlme.mtx);
}
/*
* After accepting the AddBA Request we activated a timer,
* resetting it after each frame that arrives from the originator.
*/
static void sta_rx_agg_session_timer_expired(unsigned long data)
{
/* not an elegant detour, but there is no choice as the timer passes
* only one argument, and various sta_info are needed here, so init
* flow in sta_info_create gives the TID as data, while the timer_to_id
* array gives the sta through container_of */
u8 *ptid = (u8 *)data;
u8 *timer_to_id = ptid - *ptid;
struct sta_info *sta = container_of(timer_to_id, struct sta_info,
timer_to_tid[0]);
#ifdef CONFIG_MAC80211_HT_DEBUG
printk(KERN_DEBUG "rx session timer expired on tid %d\n", (u16)*ptid);
#endif
set_bit(*ptid, sta->ampdu_mlme.tid_rx_timer_expired);
ieee80211_queue_work(&sta->local->hw, &sta->ampdu_mlme.work);
}
static void sta_rx_agg_reorder_timer_expired(unsigned long data)
{
u8 *ptid = (u8 *)data;
u8 *timer_to_id = ptid - *ptid;
struct sta_info *sta = container_of(timer_to_id, struct sta_info,
timer_to_tid[0]);
rcu_read_lock();
spin_lock(&sta->lock);
ieee80211_release_reorder_timeout(sta, *ptid);
spin_unlock(&sta->lock);
rcu_read_unlock();
}
static void ieee80211_send_addba_resp(struct ieee80211_sub_if_data *sdata, u8 *da, u16 tid,
u8 dialog_token, u16 status, u16 policy,
u16 buf_size, u16 timeout)
{
struct ieee80211_local *local = sdata->local;
struct sk_buff *skb;
struct ieee80211_mgmt *mgmt;
u16 capab;
skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
if (!skb) {
printk(KERN_DEBUG "%s: failed to allocate buffer "
"for addba resp frame\n", sdata->name);
return;
}
skb_reserve(skb, local->hw.extra_tx_headroom);
mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
memset(mgmt, 0, 24);
memcpy(mgmt->da, da, ETH_ALEN);
memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
if (sdata->vif.type == NL80211_IFTYPE_AP ||
sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
else if (sdata->vif.type == NL80211_IFTYPE_STATION)
memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
IEEE80211_STYPE_ACTION);
skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_resp));
mgmt->u.action.category = WLAN_CATEGORY_BACK;
mgmt->u.action.u.addba_resp.action_code = WLAN_ACTION_ADDBA_RESP;
mgmt->u.action.u.addba_resp.dialog_token = dialog_token;
capab = (u16)(policy << 1); /* bit 1 aggregation policy */
capab |= (u16)(tid << 2); /* bit 5:2 TID number */
capab |= (u16)(buf_size << 6); /* bit 15:6 max size of aggregation */
mgmt->u.action.u.addba_resp.capab = cpu_to_le16(capab);
mgmt->u.action.u.addba_resp.timeout = cpu_to_le16(timeout);
mgmt->u.action.u.addba_resp.status = cpu_to_le16(status);
ieee80211_tx_skb(sdata, skb);
}
void ieee80211_process_addba_request(struct ieee80211_local *local,
struct sta_info *sta,
struct ieee80211_mgmt *mgmt,
size_t len)
{
struct ieee80211_hw *hw = &local->hw;
struct ieee80211_conf *conf = &hw->conf;
struct tid_ampdu_rx *tid_agg_rx;
u16 capab, tid, timeout, ba_policy, buf_size, start_seq_num, status;
u8 dialog_token;
int ret = -EOPNOTSUPP;
/* extract session parameters from addba request frame */
dialog_token = mgmt->u.action.u.addba_req.dialog_token;
timeout = le16_to_cpu(mgmt->u.action.u.addba_req.timeout);
start_seq_num =
le16_to_cpu(mgmt->u.action.u.addba_req.start_seq_num) >> 4;
capab = le16_to_cpu(mgmt->u.action.u.addba_req.capab);
ba_policy = (capab & IEEE80211_ADDBA_PARAM_POLICY_MASK) >> 1;
tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
status = WLAN_STATUS_REQUEST_DECLINED;
if (test_sta_flags(sta, WLAN_STA_BLOCK_BA)) {
#ifdef CONFIG_MAC80211_HT_DEBUG
printk(KERN_DEBUG "Suspend in progress. "
"Denying ADDBA request\n");
#endif
goto end_no_lock;
}
/* sanity check for incoming parameters:
* check if configuration can support the BA policy
* and if buffer size does not exceeds max value */
/* XXX: check own ht delayed BA capability?? */
if (((ba_policy != 1) &&
(!(sta->sta.ht_cap.cap & IEEE80211_HT_CAP_DELAY_BA))) ||
(buf_size > IEEE80211_MAX_AMPDU_BUF)) {
status = WLAN_STATUS_INVALID_QOS_PARAM;
#ifdef CONFIG_MAC80211_HT_DEBUG
if (net_ratelimit())
printk(KERN_DEBUG "AddBA Req with bad params from "
"%pM on tid %u. policy %d, buffer size %d\n",
mgmt->sa, tid, ba_policy,
buf_size);
#endif /* CONFIG_MAC80211_HT_DEBUG */
goto end_no_lock;
}
/* determine default buffer size */
if (buf_size == 0) {
struct ieee80211_supported_band *sband;
sband = local->hw.wiphy->bands[conf->channel->band];
buf_size = IEEE80211_MIN_AMPDU_BUF;
buf_size = buf_size << sband->ht_cap.ampdu_factor;
}
/* examine state machine */
mutex_lock(&sta->ampdu_mlme.mtx);
if (sta->ampdu_mlme.tid_rx[tid]) {
#ifdef CONFIG_MAC80211_HT_DEBUG
if (net_ratelimit())
printk(KERN_DEBUG "unexpected AddBA Req from "
"%pM on tid %u\n",
mgmt->sa, tid);
#endif /* CONFIG_MAC80211_HT_DEBUG */
goto end;
}
/* prepare A-MPDU MLME for Rx aggregation */
tid_agg_rx = kmalloc(sizeof(struct tid_ampdu_rx), GFP_ATOMIC);
if (!tid_agg_rx) {
#ifdef CONFIG_MAC80211_HT_DEBUG
if (net_ratelimit())
printk(KERN_ERR "allocate rx mlme to tid %d failed\n",
tid);
#endif
goto end;
}
spin_lock_init(&tid_agg_rx->reorder_lock);
/* rx timer */
tid_agg_rx->session_timer.function = sta_rx_agg_session_timer_expired;
tid_agg_rx->session_timer.data = (unsigned long)&sta->timer_to_tid[tid];
init_timer(&tid_agg_rx->session_timer);
/* rx reorder timer */
tid_agg_rx->reorder_timer.function = sta_rx_agg_reorder_timer_expired;
tid_agg_rx->reorder_timer.data = (unsigned long)&sta->timer_to_tid[tid];
init_timer(&tid_agg_rx->reorder_timer);
/* prepare reordering buffer */
tid_agg_rx->reorder_buf =
kcalloc(buf_size, sizeof(struct sk_buff *), GFP_ATOMIC);
tid_agg_rx->reorder_time =
kcalloc(buf_size, sizeof(unsigned long), GFP_ATOMIC);
if (!tid_agg_rx->reorder_buf || !tid_agg_rx->reorder_time) {
#ifdef CONFIG_MAC80211_HT_DEBUG
if (net_ratelimit())
printk(KERN_ERR "can not allocate reordering buffer "
"to tid %d\n", tid);
#endif
kfree(tid_agg_rx->reorder_buf);
kfree(tid_agg_rx->reorder_time);
kfree(tid_agg_rx);
goto end;
}
ret = drv_ampdu_action(local, sta->sdata, IEEE80211_AMPDU_RX_START,
&sta->sta, tid, &start_seq_num);
#ifdef CONFIG_MAC80211_HT_DEBUG
printk(KERN_DEBUG "Rx A-MPDU request on tid %d result %d\n", tid, ret);
#endif /* CONFIG_MAC80211_HT_DEBUG */
if (ret) {
kfree(tid_agg_rx->reorder_buf);
kfree(tid_agg_rx->reorder_time);
kfree(tid_agg_rx);
goto end;
}
/* update data */
tid_agg_rx->dialog_token = dialog_token;
tid_agg_rx->ssn = start_seq_num;
tid_agg_rx->head_seq_num = start_seq_num;
tid_agg_rx->buf_size = buf_size;
tid_agg_rx->timeout = timeout;
tid_agg_rx->stored_mpdu_num = 0;
status = WLAN_STATUS_SUCCESS;
/* activate it for RX */
rcu_assign_pointer(sta->ampdu_mlme.tid_rx[tid], tid_agg_rx);
if (timeout)
mod_timer(&tid_agg_rx->session_timer, TU_TO_EXP_TIME(timeout));
end:
mutex_unlock(&sta->ampdu_mlme.mtx);
end_no_lock:
ieee80211_send_addba_resp(sta->sdata, sta->sta.addr, tid,
dialog_token, status, 1, buf_size, timeout);
}