mt76: implement A-MPDU rx reordering in the driver code

This is required for performing CCMP PN validation in software

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

1 files changed, 264 insertions, 0 deletions

diff --git a/drivers/net/wireless/mediatek/mt76/agg-rx.c b/drivers/net/wireless/mediatek/mt76/agg-rx.c
new file mode 100644
index 000000000000..ecd0bcd149e5
--- /dev/null
+++ b/drivers/net/wireless/mediatek/mt76/agg-rx.c
@@ -0,0 +1,264 @@
+/*
+ * 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 ieee80211_sta *sta;
+	struct sk_buff_head frames;
+	struct sk_buff *skb;
+
+	__skb_queue_head_init(&frames);
+
+	local_bh_disable();
+
+	spin_lock(&tid->lock);
+	mt76_rx_aggr_check_release(tid, &frames);
+	spin_unlock(&tid->lock);
+
+	ieee80211_queue_delayed_work(tid->dev->hw, &tid->reorder_work, REORDER_TIMEOUT);
+
+	while ((skb = __skb_dequeue(&frames)) != NULL) {
+		sta = mt76_rx_convert(skb);
+		ieee80211_rx_napi(dev->hw, sta, skb, NULL);
+	}
+
+	local_bh_enable();
+}
+
+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 mt76_wcid *wcid = status->wcid;
+	struct ieee80211_sta *sta;
+	struct mt76_rx_tid *tid;
+	bool sn_less;
+	u16 seqno, head, size;
+	u8 idx;
+
+	__skb_queue_tail(frames, skb);
+
+	sta = wcid_to_sta(wcid);
+	if (!sta || !status->aggr)
+		return;
+
+	tid = rcu_dereference(wcid->aggr[status->tid]);
+	if (!tid)
+		return;
+
+	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(sizeof(*tid) + size * sizeof(tid->reorder_buf[0]),
+		      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;
+
+	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);
+
+	cancel_delayed_work_sync(&tid->reorder_work);
+}
+
+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);