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/*
* Copyright (C) 2018 Felix Fietkau <nbd@nbd.name>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "mt76.h"
#define REORDER_TIMEOUT (HZ / 10)
static void
mt76_aggr_release(struct mt76_rx_tid *tid, struct sk_buff_head *frames, int idx)
{
struct sk_buff *skb;
tid->head = ieee80211_sn_inc(tid->head);
skb = tid->reorder_buf[idx];
if (!skb)
return;
tid->reorder_buf[idx] = NULL;
tid->nframes--;
__skb_queue_tail(frames, skb);
}
static void
mt76_rx_aggr_release_frames(struct mt76_rx_tid *tid, struct sk_buff_head *frames,
u16 head)
{
int idx;
while (ieee80211_sn_less(tid->head, head)) {
idx = tid->head % tid->size;
mt76_aggr_release(tid, frames, idx);
}
}
static void
mt76_rx_aggr_release_head(struct mt76_rx_tid *tid, struct sk_buff_head *frames)
{
int idx = tid->head % tid->size;
while (tid->reorder_buf[idx]) {
mt76_aggr_release(tid, frames, idx);
idx = tid->head % tid->size;
}
}
static void
mt76_rx_aggr_check_release(struct mt76_rx_tid *tid, struct sk_buff_head *frames)
{
struct mt76_rx_status *status;
struct sk_buff *skb;
int start, idx, nframes;
if (!tid->nframes)
return;
mt76_rx_aggr_release_head(tid, frames);
start = tid->head % tid->size;
nframes = tid->nframes;
for (idx = (tid->head + 1) % tid->size;
idx != start && nframes;
idx = (idx + 1) % tid->size) {
skb = tid->reorder_buf[idx];
if (!skb)
continue;
nframes--;
status = (struct mt76_rx_status *) skb->cb;
if (!time_after(jiffies, status->reorder_time +
REORDER_TIMEOUT))
continue;
mt76_rx_aggr_release_frames(tid, frames, status->seqno);
}
mt76_rx_aggr_release_head(tid, frames);
}
static void
mt76_rx_aggr_reorder_work(struct work_struct *work)
{
struct mt76_rx_tid *tid = container_of(work, struct mt76_rx_tid,
reorder_work.work);
struct mt76_dev *dev = tid->dev;
struct sk_buff_head frames;
int nframes;
__skb_queue_head_init(&frames);
local_bh_disable();
rcu_read_lock();
spin_lock(&tid->lock);
mt76_rx_aggr_check_release(tid, &frames);
nframes = tid->nframes;
spin_unlock(&tid->lock);
if (nframes)
ieee80211_queue_delayed_work(tid->dev->hw, &tid->reorder_work,
REORDER_TIMEOUT);
mt76_rx_complete(dev, &frames, NULL);
rcu_read_unlock();
local_bh_enable();
}
static void
mt76_rx_aggr_check_ctl(struct sk_buff *skb, struct sk_buff_head *frames)
{
struct mt76_rx_status *status = (struct mt76_rx_status *) skb->cb;
struct ieee80211_bar *bar = (struct ieee80211_bar *) skb->data;
struct mt76_wcid *wcid = status->wcid;
struct mt76_rx_tid *tid;
u16 seqno;
if (!ieee80211_is_ctl(bar->frame_control))
return;
if (!ieee80211_is_back_req(bar->frame_control))
return;
status->tid = le16_to_cpu(bar->control) >> 12;
seqno = le16_to_cpu(bar->start_seq_num) >> 4;
tid = rcu_dereference(wcid->aggr[status->tid]);
if (!tid)
return;
spin_lock_bh(&tid->lock);
mt76_rx_aggr_release_frames(tid, frames, seqno);
mt76_rx_aggr_release_head(tid, frames);
spin_unlock_bh(&tid->lock);
}
void mt76_rx_aggr_reorder(struct sk_buff *skb, struct sk_buff_head *frames)
{
struct mt76_rx_status *status = (struct mt76_rx_status *) skb->cb;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
struct mt76_wcid *wcid = status->wcid;
struct ieee80211_sta *sta;
struct mt76_rx_tid *tid;
bool sn_less;
u16 seqno, head, size;
u8 ackp, idx;
__skb_queue_tail(frames, skb);
sta = wcid_to_sta(wcid);
if (!sta)
return;
if (!status->aggr) {
mt76_rx_aggr_check_ctl(skb, frames);
return;
}
/* not part of a BA session */
ackp = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_ACK_POLICY_MASK;
if (ackp != IEEE80211_QOS_CTL_ACK_POLICY_BLOCKACK &&
ackp != IEEE80211_QOS_CTL_ACK_POLICY_NORMAL)
return;
tid = rcu_dereference(wcid->aggr[status->tid]);
if (!tid)
return;
status->flag |= RX_FLAG_DUP_VALIDATED;
spin_lock_bh(&tid->lock);
if (tid->stopped)
goto out;
head = tid->head;
seqno = status->seqno;
size = tid->size;
sn_less = ieee80211_sn_less(seqno, head);
if (!tid->started) {
if (sn_less)
goto out;
tid->started = true;
}
if (sn_less) {
__skb_unlink(skb, frames);
dev_kfree_skb(skb);
goto out;
}
if (seqno == head) {
tid->head = ieee80211_sn_inc(head);
if (tid->nframes)
mt76_rx_aggr_release_head(tid, frames);
goto out;
}
__skb_unlink(skb, frames);
/*
* Frame sequence number exceeds buffering window, free up some space
* by releasing previous frames
*/
if (!ieee80211_sn_less(seqno, head + size)) {
head = ieee80211_sn_inc(ieee80211_sn_sub(seqno, size));
mt76_rx_aggr_release_frames(tid, frames, head);
}
idx = seqno % size;
/* Discard if the current slot is already in use */
if (tid->reorder_buf[idx]) {
dev_kfree_skb(skb);
goto out;
}
status->reorder_time = jiffies;
tid->reorder_buf[idx] = skb;
tid->nframes++;
mt76_rx_aggr_release_head(tid, frames);
ieee80211_queue_delayed_work(tid->dev->hw, &tid->reorder_work, REORDER_TIMEOUT);
out:
spin_unlock_bh(&tid->lock);
}
int mt76_rx_aggr_start(struct mt76_dev *dev, struct mt76_wcid *wcid, u8 tidno,
u16 ssn, u8 size)
{
struct mt76_rx_tid *tid;
mt76_rx_aggr_stop(dev, wcid, tidno);
tid = kzalloc(struct_size(tid, reorder_buf, size), GFP_KERNEL);
if (!tid)
return -ENOMEM;
tid->dev = dev;
tid->head = ssn;
tid->size = size;
INIT_DELAYED_WORK(&tid->reorder_work, mt76_rx_aggr_reorder_work);
spin_lock_init(&tid->lock);
rcu_assign_pointer(wcid->aggr[tidno], tid);
return 0;
}
EXPORT_SYMBOL_GPL(mt76_rx_aggr_start);
static void mt76_rx_aggr_shutdown(struct mt76_dev *dev, struct mt76_rx_tid *tid)
{
u8 size = tid->size;
int i;
cancel_delayed_work(&tid->reorder_work);
spin_lock_bh(&tid->lock);
tid->stopped = true;
for (i = 0; tid->nframes && i < size; i++) {
struct sk_buff *skb = tid->reorder_buf[i];
if (!skb)
continue;
tid->nframes--;
dev_kfree_skb(skb);
}
spin_unlock_bh(&tid->lock);
}
void mt76_rx_aggr_stop(struct mt76_dev *dev, struct mt76_wcid *wcid, u8 tidno)
{
struct mt76_rx_tid *tid;
rcu_read_lock();
tid = rcu_dereference(wcid->aggr[tidno]);
if (tid) {
rcu_assign_pointer(wcid->aggr[tidno], NULL);
mt76_rx_aggr_shutdown(dev, tid);
kfree_rcu(tid, rcu_head);
}
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(mt76_rx_aggr_stop);
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