linux/net/mac80211/agg-rx.c
Jouni Malinen 4d050f1dae mac80211: Add a timeout for frames in the RX reorder buffer
This patch allows skbs to be released from the RX reorder buffer in
case they have been there for an unexpectedly long time without us
having received the missing frames before them. Previously, these
frames were only released when the reorder window moved and that could
take very long time unless new frames were received constantly (e.g.,
TCP connections could be killed more or less indefinitely).

This situation should not happen very frequently, but it looks like
there are some scenarious that trigger it for some reason. As such,
this should be considered mostly a workaround to speed up recovery
from unexpected siutation that could result in connections hanging for
long periods of time.

The changes here will only check for timeout situation when adding new
RX frames to the reorder buffer. It does not handle all possible
cases, but seems to help for most cases that could result from common
network usage (e.g., TCP retrying at least couple of times). For more
completely coverage, a timer could be used to periodically check
whether there are any frames remaining in the reorder buffer if no new
frames are received.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-05-06 15:15:04 -04:00

316 lines
9.8 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 2007-2008, 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.
*/
#include <linux/ieee80211.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "driver-ops.h"
void __ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
u16 initiator, u16 reason)
{
struct ieee80211_local *local = sta->local;
int i;
/* check if TID is in operational state */
spin_lock_bh(&sta->lock);
if (sta->ampdu_mlme.tid_state_rx[tid] != HT_AGG_STATE_OPERATIONAL) {
spin_unlock_bh(&sta->lock);
return;
}
sta->ampdu_mlme.tid_state_rx[tid] =
HT_AGG_STATE_REQ_STOP_BA_MSK |
(initiator << HT_AGG_STATE_INITIATOR_SHIFT);
spin_unlock_bh(&sta->lock);
#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, IEEE80211_AMPDU_RX_STOP,
&sta->sta, tid, NULL))
printk(KERN_DEBUG "HW problem - can not stop rx "
"aggregation for tid %d\n", tid);
/* shutdown timer has not expired */
if (initiator != WLAN_BACK_TIMER)
del_timer_sync(&sta->ampdu_mlme.tid_rx[tid]->session_timer);
/* check if this is a self generated aggregation halt */
if (initiator == WLAN_BACK_RECIPIENT || initiator == WLAN_BACK_TIMER)
ieee80211_send_delba(sta->sdata, sta->sta.addr,
tid, 0, reason);
/* free the reordering buffer */
for (i = 0; i < sta->ampdu_mlme.tid_rx[tid]->buf_size; i++) {
if (sta->ampdu_mlme.tid_rx[tid]->reorder_buf[i]) {
/* release the reordered frames */
dev_kfree_skb(sta->ampdu_mlme.tid_rx[tid]->reorder_buf[i]);
sta->ampdu_mlme.tid_rx[tid]->stored_mpdu_num--;
sta->ampdu_mlme.tid_rx[tid]->reorder_buf[i] = NULL;
}
}
spin_lock_bh(&sta->lock);
/* free resources */
kfree(sta->ampdu_mlme.tid_rx[tid]->reorder_buf);
kfree(sta->ampdu_mlme.tid_rx[tid]->reorder_time);
if (!sta->ampdu_mlme.tid_rx[tid]->shutdown) {
kfree(sta->ampdu_mlme.tid_rx[tid]);
sta->ampdu_mlme.tid_rx[tid] = NULL;
}
sta->ampdu_mlme.tid_state_rx[tid] = HT_AGG_STATE_IDLE;
spin_unlock_bh(&sta->lock);
}
void ieee80211_sta_stop_rx_ba_session(struct ieee80211_sub_if_data *sdata, u8 *ra, u16 tid,
u16 initiator, u16 reason)
{
struct ieee80211_local *local = sdata->local;
struct sta_info *sta;
/* stop HW Rx aggregation. ampdu_action existence
* already verified in session init so we add the BUG_ON */
BUG_ON(!local->ops->ampdu_action);
rcu_read_lock();
sta = sta_info_get(local, ra);
if (!sta) {
rcu_read_unlock();
return;
}
__ieee80211_stop_rx_ba_session(sta, tid, initiator, reason);
rcu_read_unlock();
}
/*
* After accepting the AddBA Request we activated a timer,
* resetting it after each frame that arrives from the originator.
* if this timer expires ieee80211_sta_stop_rx_ba_session will be executed.
*/
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
ieee80211_sta_stop_rx_ba_session(sta->sdata, sta->sta.addr,
(u16)*ptid, WLAN_BACK_TIMER,
WLAN_REASON_QSTA_TIMEOUT);
}
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->dev->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->dev->dev_addr, ETH_ALEN);
if (sdata->vif.type == NL80211_IFTYPE_AP ||
sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
memcpy(mgmt->bssid, sdata->dev->dev_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, 1);
}
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_SUSPEND)) {
#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 */
spin_lock_bh(&sta->lock);
if (sta->ampdu_mlme.tid_state_rx[tid] != HT_AGG_STATE_IDLE) {
#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 */
sta->ampdu_mlme.tid_rx[tid] =
kmalloc(sizeof(struct tid_ampdu_rx), GFP_ATOMIC);
if (!sta->ampdu_mlme.tid_rx[tid]) {
#ifdef CONFIG_MAC80211_HT_DEBUG
if (net_ratelimit())
printk(KERN_ERR "allocate rx mlme to tid %d failed\n",
tid);
#endif
goto end;
}
/* rx timer */
sta->ampdu_mlme.tid_rx[tid]->session_timer.function =
sta_rx_agg_session_timer_expired;
sta->ampdu_mlme.tid_rx[tid]->session_timer.data =
(unsigned long)&sta->timer_to_tid[tid];
init_timer(&sta->ampdu_mlme.tid_rx[tid]->session_timer);
tid_agg_rx = sta->ampdu_mlme.tid_rx[tid];
/* 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(sta->ampdu_mlme.tid_rx[tid]);
sta->ampdu_mlme.tid_rx[tid] = NULL;
goto end;
}
ret = drv_ampdu_action(local, 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);
sta->ampdu_mlme.tid_rx[tid] = NULL;
goto end;
}
/* change state and send addba resp */
sta->ampdu_mlme.tid_state_rx[tid] = HT_AGG_STATE_OPERATIONAL;
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;
end:
spin_unlock_bh(&sta->lock);
end_no_lock:
ieee80211_send_addba_resp(sta->sdata, sta->sta.addr, tid,
dialog_token, status, 1, buf_size, timeout);
}