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_after(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 u16 seqno;
126
127 if (!ieee80211_is_ctl(bar->frame_control))
128 return;
129
130 if (!ieee80211_is_back_req(bar->frame_control))
131 return;
132
133 status->tid = le16_to_cpu(bar->control) >> 12;
134 seqno = IEEE80211_SEQ_TO_SN(le16_to_cpu(bar->start_seq_num));
135 tid = rcu_dereference(wcid->aggr[status->tid]);
136 if (!tid)
137 return;
138
139 spin_lock_bh(&tid->lock);
140 if (!tid->stopped) {
141 mt76_rx_aggr_release_frames(tid, frames, seqno);
142 mt76_rx_aggr_release_head(tid, frames);
143 }
144 spin_unlock_bh(&tid->lock);
145 }
146
mt76_rx_aggr_reorder(struct sk_buff * skb,struct sk_buff_head * frames)147 void mt76_rx_aggr_reorder(struct sk_buff *skb, struct sk_buff_head *frames)
148 {
149 struct mt76_rx_status *status = (struct mt76_rx_status *)skb->cb;
150 struct ieee80211_hdr *hdr = mt76_skb_get_hdr(skb);
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 ackp;
157
158 __skb_queue_tail(frames, skb);
159
160 sta = wcid_to_sta(wcid);
161 if (!sta)
162 return;
163
164 if (!status->aggr) {
165 mt76_rx_aggr_check_ctl(skb, frames);
166 return;
167 }
168
169 /* not part of a BA session */
170 ackp = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_ACK_POLICY_MASK;
171 if (ackp != IEEE80211_QOS_CTL_ACK_POLICY_BLOCKACK &&
172 ackp != IEEE80211_QOS_CTL_ACK_POLICY_NORMAL)
173 return;
174
175 tid = rcu_dereference(wcid->aggr[status->tid]);
176 if (!tid)
177 return;
178
179 status->flag |= RX_FLAG_DUP_VALIDATED;
180 spin_lock_bh(&tid->lock);
181
182 if (tid->stopped)
183 goto out;
184
185 head = tid->head;
186 seqno = status->seqno;
187 size = tid->size;
188 sn_less = ieee80211_sn_less(seqno, head);
189
190 if (!tid->started) {
191 if (sn_less)
192 goto out;
193
194 tid->started = true;
195 }
196
197 if (sn_less) {
198 __skb_unlink(skb, frames);
199 dev_kfree_skb(skb);
200 goto out;
201 }
202
203 if (seqno == head) {
204 tid->head = ieee80211_sn_inc(head);
205 if (tid->nframes)
206 mt76_rx_aggr_release_head(tid, frames);
207 goto out;
208 }
209
210 __skb_unlink(skb, frames);
211
212 /*
213 * Frame sequence number exceeds buffering window, free up some space
214 * by releasing previous frames
215 */
216 if (!ieee80211_sn_less(seqno, head + size)) {
217 head = ieee80211_sn_inc(ieee80211_sn_sub(seqno, size));
218 mt76_rx_aggr_release_frames(tid, frames, head);
219 }
220
221 idx = seqno % size;
222
223 /* Discard if the current slot is already in use */
224 if (tid->reorder_buf[idx]) {
225 dev_kfree_skb(skb);
226 goto out;
227 }
228
229 status->reorder_time = jiffies;
230 tid->reorder_buf[idx] = skb;
231 tid->nframes++;
232 mt76_rx_aggr_release_head(tid, frames);
233
234 ieee80211_queue_delayed_work(tid->dev->hw, &tid->reorder_work,
235 mt76_aggr_tid_to_timeo(tid->num));
236
237 out:
238 spin_unlock_bh(&tid->lock);
239 }
240
mt76_rx_aggr_start(struct mt76_dev * dev,struct mt76_wcid * wcid,u8 tidno,u16 ssn,u16 size)241 int mt76_rx_aggr_start(struct mt76_dev *dev, struct mt76_wcid *wcid, u8 tidno,
242 u16 ssn, u16 size)
243 {
244 struct mt76_rx_tid *tid;
245
246 mt76_rx_aggr_stop(dev, wcid, tidno);
247
248 tid = kzalloc(struct_size(tid, reorder_buf, size), GFP_KERNEL);
249 if (!tid)
250 return -ENOMEM;
251
252 tid->dev = dev;
253 tid->head = ssn;
254 tid->size = size;
255 tid->num = tidno;
256 INIT_DELAYED_WORK(&tid->reorder_work, mt76_rx_aggr_reorder_work);
257 spin_lock_init(&tid->lock);
258
259 rcu_assign_pointer(wcid->aggr[tidno], tid);
260
261 return 0;
262 }
263 EXPORT_SYMBOL_GPL(mt76_rx_aggr_start);
264
mt76_rx_aggr_shutdown(struct mt76_dev * dev,struct mt76_rx_tid * tid)265 static void mt76_rx_aggr_shutdown(struct mt76_dev *dev, struct mt76_rx_tid *tid)
266 {
267 u16 size = tid->size;
268 int i;
269
270 spin_lock_bh(&tid->lock);
271
272 tid->stopped = true;
273 for (i = 0; tid->nframes && i < size; i++) {
274 struct sk_buff *skb = tid->reorder_buf[i];
275
276 if (!skb)
277 continue;
278
279 tid->reorder_buf[i] = NULL;
280 tid->nframes--;
281 dev_kfree_skb(skb);
282 }
283
284 spin_unlock_bh(&tid->lock);
285
286 cancel_delayed_work_sync(&tid->reorder_work);
287 }
288
mt76_rx_aggr_stop(struct mt76_dev * dev,struct mt76_wcid * wcid,u8 tidno)289 void mt76_rx_aggr_stop(struct mt76_dev *dev, struct mt76_wcid *wcid, u8 tidno)
290 {
291 struct mt76_rx_tid *tid = NULL;
292
293 tid = rcu_replace_pointer(wcid->aggr[tidno], tid,
294 lockdep_is_held(&dev->mutex));
295 if (tid) {
296 mt76_rx_aggr_shutdown(dev, tid);
297 kfree_rcu(tid, rcu_head);
298 }
299 }
300 EXPORT_SYMBOL_GPL(mt76_rx_aggr_stop);
301