1 // SPDX-License-Identifier: ISC
2 /*
3 * Copyright (C) 2018 Felix Fietkau <nbd@nbd.name>
4 */
5 #include "mt76.h"
6
mt76_aggr_tid_to_timeo(u8 tidno)7 static unsigned long mt76_aggr_tid_to_timeo(u8 tidno)
8 {
9 /* Currently voice traffic (AC_VO) always runs without aggregation,
10 * no special handling is needed. AC_BE/AC_BK use tids 0-3. Just check
11 * for non AC_BK/AC_BE and set smaller timeout for it. */
12 return HZ / (tidno >= 4 ? 25 : 10);
13 }
14
15 static void
mt76_aggr_release(struct mt76_rx_tid * tid,struct sk_buff_head * frames,int idx)16 mt76_aggr_release(struct mt76_rx_tid *tid, struct sk_buff_head *frames, int idx)
17 {
18 struct sk_buff *skb;
19
20 tid->head = ieee80211_sn_inc(tid->head);
21
22 skb = tid->reorder_buf[idx];
23 if (!skb)
24 return;
25
26 tid->reorder_buf[idx] = NULL;
27 tid->nframes--;
28 __skb_queue_tail(frames, skb);
29 }
30
31 static void
mt76_rx_aggr_release_frames(struct mt76_rx_tid * tid,struct sk_buff_head * frames,u16 head)32 mt76_rx_aggr_release_frames(struct mt76_rx_tid *tid,
33 struct sk_buff_head *frames,
34 u16 head)
35 {
36 int idx;
37
38 while (ieee80211_sn_less(tid->head, head)) {
39 idx = tid->head % tid->size;
40 mt76_aggr_release(tid, frames, idx);
41 }
42 }
43
44 static void
mt76_rx_aggr_release_head(struct mt76_rx_tid * tid,struct sk_buff_head * frames)45 mt76_rx_aggr_release_head(struct mt76_rx_tid *tid, struct sk_buff_head *frames)
46 {
47 int idx = tid->head % tid->size;
48
49 while (tid->reorder_buf[idx]) {
50 mt76_aggr_release(tid, frames, idx);
51 idx = tid->head % tid->size;
52 }
53 }
54
55 static void
mt76_rx_aggr_check_release(struct mt76_rx_tid * tid,struct sk_buff_head * frames)56 mt76_rx_aggr_check_release(struct mt76_rx_tid *tid, struct sk_buff_head *frames)
57 {
58 struct mt76_rx_status *status;
59 struct sk_buff *skb;
60 int start, idx, nframes;
61
62 if (!tid->nframes)
63 return;
64
65 mt76_rx_aggr_release_head(tid, frames);
66
67 start = tid->head % tid->size;
68 nframes = tid->nframes;
69
70 for (idx = (tid->head + 1) % tid->size;
71 idx != start && nframes;
72 idx = (idx + 1) % tid->size) {
73 skb = tid->reorder_buf[idx];
74 if (!skb)
75 continue;
76
77 nframes--;
78 status = (struct mt76_rx_status *)skb->cb;
79 if (!time_after32(jiffies,
80 status->reorder_time +
81 mt76_aggr_tid_to_timeo(tid->num)))
82 continue;
83
84 mt76_rx_aggr_release_frames(tid, frames, status->seqno);
85 }
86
87 mt76_rx_aggr_release_head(tid, frames);
88 }
89
90 static void
mt76_rx_aggr_reorder_work(struct work_struct * work)91 mt76_rx_aggr_reorder_work(struct work_struct *work)
92 {
93 struct mt76_rx_tid *tid = container_of(work, struct mt76_rx_tid,
94 reorder_work.work);
95 struct mt76_dev *dev = tid->dev;
96 struct sk_buff_head frames;
97 int nframes;
98
99 __skb_queue_head_init(&frames);
100
101 local_bh_disable();
102 rcu_read_lock();
103
104 spin_lock(&tid->lock);
105 mt76_rx_aggr_check_release(tid, &frames);
106 nframes = tid->nframes;
107 spin_unlock(&tid->lock);
108
109 if (nframes)
110 ieee80211_queue_delayed_work(tid->dev->hw, &tid->reorder_work,
111 mt76_aggr_tid_to_timeo(tid->num));
112 mt76_rx_complete(dev, &frames, NULL);
113
114 rcu_read_unlock();
115 local_bh_enable();
116 }
117
118 static void
mt76_rx_aggr_check_ctl(struct sk_buff * skb,struct sk_buff_head * frames)119 mt76_rx_aggr_check_ctl(struct sk_buff *skb, struct sk_buff_head *frames)
120 {
121 struct mt76_rx_status *status = (struct mt76_rx_status *)skb->cb;
122 struct ieee80211_bar *bar = mt76_skb_get_hdr(skb);
123 struct mt76_wcid *wcid = status->wcid;
124 struct mt76_rx_tid *tid;
125 u8 tidno = status->qos_ctl & IEEE80211_QOS_CTL_TID_MASK;
126 u16 seqno;
127
128 if (!ieee80211_is_ctl(bar->frame_control))
129 return;
130
131 if (!ieee80211_is_back_req(bar->frame_control))
132 return;
133
134 status->qos_ctl = tidno = le16_to_cpu(bar->control) >> 12;
135 seqno = IEEE80211_SEQ_TO_SN(le16_to_cpu(bar->start_seq_num));
136 tid = rcu_dereference(wcid->aggr[tidno]);
137 if (!tid)
138 return;
139
140 spin_lock_bh(&tid->lock);
141 if (!tid->stopped) {
142 mt76_rx_aggr_release_frames(tid, frames, seqno);
143 mt76_rx_aggr_release_head(tid, frames);
144 }
145 spin_unlock_bh(&tid->lock);
146 }
147
mt76_rx_aggr_reorder(struct sk_buff * skb,struct sk_buff_head * frames)148 void mt76_rx_aggr_reorder(struct sk_buff *skb, struct sk_buff_head *frames)
149 {
150 struct mt76_rx_status *status = (struct mt76_rx_status *)skb->cb;
151 struct mt76_wcid *wcid = status->wcid;
152 struct ieee80211_sta *sta;
153 struct mt76_rx_tid *tid;
154 bool sn_less;
155 u16 seqno, head, size, idx;
156 u8 tidno = status->qos_ctl & IEEE80211_QOS_CTL_TID_MASK;
157 u8 ackp;
158
159 __skb_queue_tail(frames, skb);
160
161 sta = wcid_to_sta(wcid);
162 if (!sta)
163 return;
164
165 if (!status->aggr) {
166 if (!(status->flag & RX_FLAG_8023))
167 mt76_rx_aggr_check_ctl(skb, frames);
168 return;
169 }
170
171 /* not part of a BA session */
172 ackp = status->qos_ctl & IEEE80211_QOS_CTL_ACK_POLICY_MASK;
173 if (ackp == IEEE80211_QOS_CTL_ACK_POLICY_NOACK)
174 return;
175
176 tid = rcu_dereference(wcid->aggr[tidno]);
177 if (!tid)
178 return;
179
180 status->flag |= RX_FLAG_DUP_VALIDATED;
181 spin_lock_bh(&tid->lock);
182
183 if (tid->stopped)
184 goto out;
185
186 head = tid->head;
187 seqno = status->seqno;
188 size = tid->size;
189 sn_less = ieee80211_sn_less(seqno, head);
190
191 if (!tid->started) {
192 if (sn_less)
193 goto out;
194
195 tid->started = true;
196 }
197
198 if (sn_less) {
199 __skb_unlink(skb, frames);
200 dev_kfree_skb(skb);
201 goto out;
202 }
203
204 if (seqno == head) {
205 tid->head = ieee80211_sn_inc(head);
206 if (tid->nframes)
207 mt76_rx_aggr_release_head(tid, frames);
208 goto out;
209 }
210
211 __skb_unlink(skb, frames);
212
213 /*
214 * Frame sequence number exceeds buffering window, free up some space
215 * by releasing previous frames
216 */
217 if (!ieee80211_sn_less(seqno, head + size)) {
218 head = ieee80211_sn_inc(ieee80211_sn_sub(seqno, size));
219 mt76_rx_aggr_release_frames(tid, frames, head);
220 }
221
222 idx = seqno % size;
223
224 /* Discard if the current slot is already in use */
225 if (tid->reorder_buf[idx]) {
226 dev_kfree_skb(skb);
227 goto out;
228 }
229
230 status->reorder_time = jiffies;
231 tid->reorder_buf[idx] = skb;
232 tid->nframes++;
233 mt76_rx_aggr_release_head(tid, frames);
234
235 ieee80211_queue_delayed_work(tid->dev->hw, &tid->reorder_work,
236 mt76_aggr_tid_to_timeo(tid->num));
237
238 out:
239 spin_unlock_bh(&tid->lock);
240 }
241
mt76_rx_aggr_start(struct mt76_dev * dev,struct mt76_wcid * wcid,u8 tidno,u16 ssn,u16 size)242 int mt76_rx_aggr_start(struct mt76_dev *dev, struct mt76_wcid *wcid, u8 tidno,
243 u16 ssn, u16 size)
244 {
245 struct mt76_rx_tid *tid;
246
247 mt76_rx_aggr_stop(dev, wcid, tidno);
248
249 tid = kzalloc(struct_size(tid, reorder_buf, size), GFP_KERNEL);
250 if (!tid)
251 return -ENOMEM;
252
253 tid->dev = dev;
254 tid->head = ssn;
255 tid->size = size;
256 tid->num = tidno;
257 INIT_DELAYED_WORK(&tid->reorder_work, mt76_rx_aggr_reorder_work);
258 spin_lock_init(&tid->lock);
259
260 rcu_assign_pointer(wcid->aggr[tidno], tid);
261
262 return 0;
263 }
264 EXPORT_SYMBOL_GPL(mt76_rx_aggr_start);
265
mt76_rx_aggr_shutdown(struct mt76_dev * dev,struct mt76_rx_tid * tid)266 static void mt76_rx_aggr_shutdown(struct mt76_dev *dev, struct mt76_rx_tid *tid)
267 {
268 u16 size = tid->size;
269 int i;
270
271 spin_lock_bh(&tid->lock);
272
273 tid->stopped = true;
274 for (i = 0; tid->nframes && i < size; i++) {
275 struct sk_buff *skb = tid->reorder_buf[i];
276
277 if (!skb)
278 continue;
279
280 tid->reorder_buf[i] = NULL;
281 tid->nframes--;
282 dev_kfree_skb(skb);
283 }
284
285 spin_unlock_bh(&tid->lock);
286
287 cancel_delayed_work_sync(&tid->reorder_work);
288 }
289
mt76_rx_aggr_stop(struct mt76_dev * dev,struct mt76_wcid * wcid,u8 tidno)290 void mt76_rx_aggr_stop(struct mt76_dev *dev, struct mt76_wcid *wcid, u8 tidno)
291 {
292 struct mt76_rx_tid *tid = NULL;
293
294 tid = rcu_replace_pointer(wcid->aggr[tidno], tid,
295 lockdep_is_held(&dev->mutex));
296 if (tid) {
297 mt76_rx_aggr_shutdown(dev, tid);
298 kfree_rcu(tid, rcu_head);
299 }
300 }
301 EXPORT_SYMBOL_GPL(mt76_rx_aggr_stop);
302