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_BLOCKACK &&
174 ackp != IEEE80211_QOS_CTL_ACK_POLICY_NORMAL)
175 return;
176
177 tid = rcu_dereference(wcid->aggr[tidno]);
178 if (!tid)
179 return;
180
181 status->flag |= RX_FLAG_DUP_VALIDATED;
182 spin_lock_bh(&tid->lock);
183
184 if (tid->stopped)
185 goto out;
186
187 head = tid->head;
188 seqno = status->seqno;
189 size = tid->size;
190 sn_less = ieee80211_sn_less(seqno, head);
191
192 if (!tid->started) {
193 if (sn_less)
194 goto out;
195
196 tid->started = true;
197 }
198
199 if (sn_less) {
200 __skb_unlink(skb, frames);
201 dev_kfree_skb(skb);
202 goto out;
203 }
204
205 if (seqno == head) {
206 tid->head = ieee80211_sn_inc(head);
207 if (tid->nframes)
208 mt76_rx_aggr_release_head(tid, frames);
209 goto out;
210 }
211
212 __skb_unlink(skb, frames);
213
214 /*
215 * Frame sequence number exceeds buffering window, free up some space
216 * by releasing previous frames
217 */
218 if (!ieee80211_sn_less(seqno, head + size)) {
219 head = ieee80211_sn_inc(ieee80211_sn_sub(seqno, size));
220 mt76_rx_aggr_release_frames(tid, frames, head);
221 }
222
223 idx = seqno % size;
224
225 /* Discard if the current slot is already in use */
226 if (tid->reorder_buf[idx]) {
227 dev_kfree_skb(skb);
228 goto out;
229 }
230
231 status->reorder_time = jiffies;
232 tid->reorder_buf[idx] = skb;
233 tid->nframes++;
234 mt76_rx_aggr_release_head(tid, frames);
235
236 ieee80211_queue_delayed_work(tid->dev->hw, &tid->reorder_work,
237 mt76_aggr_tid_to_timeo(tid->num));
238
239 out:
240 spin_unlock_bh(&tid->lock);
241 }
242
mt76_rx_aggr_start(struct mt76_dev * dev,struct mt76_wcid * wcid,u8 tidno,u16 ssn,u16 size)243 int mt76_rx_aggr_start(struct mt76_dev *dev, struct mt76_wcid *wcid, u8 tidno,
244 u16 ssn, u16 size)
245 {
246 struct mt76_rx_tid *tid;
247
248 mt76_rx_aggr_stop(dev, wcid, tidno);
249
250 tid = kzalloc(struct_size(tid, reorder_buf, size), GFP_KERNEL);
251 if (!tid)
252 return -ENOMEM;
253
254 tid->dev = dev;
255 tid->head = ssn;
256 tid->size = size;
257 tid->num = tidno;
258 INIT_DELAYED_WORK(&tid->reorder_work, mt76_rx_aggr_reorder_work);
259 spin_lock_init(&tid->lock);
260
261 rcu_assign_pointer(wcid->aggr[tidno], tid);
262
263 return 0;
264 }
265 EXPORT_SYMBOL_GPL(mt76_rx_aggr_start);
266
mt76_rx_aggr_shutdown(struct mt76_dev * dev,struct mt76_rx_tid * tid)267 static void mt76_rx_aggr_shutdown(struct mt76_dev *dev, struct mt76_rx_tid *tid)
268 {
269 u16 size = tid->size;
270 int i;
271
272 spin_lock_bh(&tid->lock);
273
274 tid->stopped = true;
275 for (i = 0; tid->nframes && i < size; i++) {
276 struct sk_buff *skb = tid->reorder_buf[i];
277
278 if (!skb)
279 continue;
280
281 tid->reorder_buf[i] = NULL;
282 tid->nframes--;
283 dev_kfree_skb(skb);
284 }
285
286 spin_unlock_bh(&tid->lock);
287
288 cancel_delayed_work_sync(&tid->reorder_work);
289 }
290
mt76_rx_aggr_stop(struct mt76_dev * dev,struct mt76_wcid * wcid,u8 tidno)291 void mt76_rx_aggr_stop(struct mt76_dev *dev, struct mt76_wcid *wcid, u8 tidno)
292 {
293 struct mt76_rx_tid *tid = NULL;
294
295 tid = rcu_replace_pointer(wcid->aggr[tidno], tid,
296 lockdep_is_held(&dev->mutex));
297 if (tid) {
298 mt76_rx_aggr_shutdown(dev, tid);
299 kfree_rcu(tid, rcu_head);
300 }
301 }
302 EXPORT_SYMBOL_GPL(mt76_rx_aggr_stop);
303