1 /* $NetBSD: ieee80211_rssadapt.c,v 1.9 2005/02/26 22:45:09 perry Exp $ */
2 /*-
3 * SPDX-License-Identifier: BSD-3-Clause
4 *
5 * Copyright (c) 2010 Rui Paulo <rpaulo@FreeBSD.org>
6 * Copyright (c) 2003, 2004 David Young. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or
9 * without modification, are permitted provided that the following
10 * conditions are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above
14 * copyright notice, this list of conditions and the following
15 * disclaimer in the documentation and/or other materials provided
16 * with the distribution.
17 * 3. The name of David Young may not be used to endorse or promote
18 * products derived from this software without specific prior
19 * written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY
22 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
23 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
24 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL David
25 * Young BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
26 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
27 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
29 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
32 * OF SUCH DAMAGE.
33 */
34 #include "opt_wlan.h"
35
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/kernel.h>
39 #include <sys/malloc.h>
40 #include <sys/module.h>
41 #include <sys/socket.h>
42 #include <sys/sysctl.h>
43
44 #include <net/if.h>
45 #include <net/if_var.h>
46 #include <net/if_media.h>
47 #include <net/ethernet.h>
48
49 #include <net80211/ieee80211_var.h>
50 #include <net80211/ieee80211_rssadapt.h>
51 #include <net80211/ieee80211_ratectl.h>
52
53 struct rssadapt_expavgctl {
54 /* RSS threshold decay. */
55 u_int rc_decay_denom;
56 u_int rc_decay_old;
57 /* RSS threshold update. */
58 u_int rc_thresh_denom;
59 u_int rc_thresh_old;
60 /* RSS average update. */
61 u_int rc_avgrssi_denom;
62 u_int rc_avgrssi_old;
63 };
64
65 static struct rssadapt_expavgctl master_expavgctl = {
66 .rc_decay_denom = 16,
67 .rc_decay_old = 15,
68 .rc_thresh_denom = 8,
69 .rc_thresh_old = 4,
70 .rc_avgrssi_denom = 8,
71 .rc_avgrssi_old = 4
72 };
73
74 #ifdef interpolate
75 #undef interpolate
76 #endif
77 #define interpolate(parm, old, new) ((parm##_old * (old) + \
78 (parm##_denom - parm##_old) * (new)) / \
79 parm##_denom)
80
81 static void rssadapt_setinterval(const struct ieee80211vap *, int);
82 static void rssadapt_init(struct ieee80211vap *);
83 static void rssadapt_deinit(struct ieee80211vap *);
84 static void rssadapt_updatestats(struct ieee80211_rssadapt_node *);
85 static void rssadapt_node_init(struct ieee80211_node *);
86 static void rssadapt_node_deinit(struct ieee80211_node *);
87 static int rssadapt_rate(struct ieee80211_node *, void *, uint32_t);
88 static void rssadapt_lower_rate(struct ieee80211_rssadapt_node *, int, int);
89 static void rssadapt_raise_rate(struct ieee80211_rssadapt_node *,
90 int, int);
91 static void rssadapt_tx_complete(const struct ieee80211_node *,
92 const struct ieee80211_ratectl_tx_status *);
93 static void rssadapt_sysctlattach(struct ieee80211vap *,
94 struct sysctl_ctx_list *, struct sysctl_oid *);
95
96 /* number of references from net80211 layer */
97 static int nrefs = 0;
98
99 static const struct ieee80211_ratectl rssadapt = {
100 .ir_name = "rssadapt",
101 .ir_attach = NULL,
102 .ir_detach = NULL,
103 .ir_init = rssadapt_init,
104 .ir_deinit = rssadapt_deinit,
105 .ir_node_init = rssadapt_node_init,
106 .ir_node_deinit = rssadapt_node_deinit,
107 .ir_rate = rssadapt_rate,
108 .ir_tx_complete = rssadapt_tx_complete,
109 .ir_tx_update = NULL,
110 .ir_setinterval = rssadapt_setinterval,
111 };
112 IEEE80211_RATECTL_MODULE(rssadapt, 1);
113 IEEE80211_RATECTL_ALG(rssadapt, IEEE80211_RATECTL_RSSADAPT, rssadapt);
114
115 static void
rssadapt_setinterval(const struct ieee80211vap * vap,int msecs)116 rssadapt_setinterval(const struct ieee80211vap *vap, int msecs)
117 {
118 struct ieee80211_rssadapt *rs = vap->iv_rs;
119
120 if (!rs)
121 return;
122
123 if (msecs < 100)
124 msecs = 100;
125 rs->interval = msecs_to_ticks(msecs);
126 }
127
128 static void
rssadapt_init(struct ieee80211vap * vap)129 rssadapt_init(struct ieee80211vap *vap)
130 {
131 struct ieee80211_rssadapt *rs;
132
133 KASSERT(vap->iv_rs == NULL, ("%s: iv_rs already initialized",
134 __func__));
135
136 nrefs++; /* XXX locking */
137 vap->iv_rs = rs = IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt),
138 M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
139 if (rs == NULL) {
140 net80211_vap_printf(vap, "couldn't alloc ratectl structure\n");
141 return;
142 }
143 rs->vap = vap;
144 rssadapt_setinterval(vap, 500 /* msecs */);
145 rssadapt_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
146 }
147
148 static void
rssadapt_deinit(struct ieee80211vap * vap)149 rssadapt_deinit(struct ieee80211vap *vap)
150 {
151 IEEE80211_FREE(vap->iv_rs, M_80211_RATECTL);
152 KASSERT(nrefs > 0, ("imbalanced attach/detach"));
153 nrefs--; /* XXX locking */
154 }
155
156 static void
rssadapt_updatestats(struct ieee80211_rssadapt_node * ra)157 rssadapt_updatestats(struct ieee80211_rssadapt_node *ra)
158 {
159 long interval;
160
161 ra->ra_pktrate = (ra->ra_pktrate + 10*(ra->ra_nfail + ra->ra_nok))/2;
162 ra->ra_nfail = ra->ra_nok = 0;
163
164 /*
165 * A node is eligible for its rate to be raised every 1/10 to 10
166 * seconds, more eligible in proportion to recent packet rates.
167 */
168 interval = MAX(10*1000, 10*1000 / MAX(1, 10 * ra->ra_pktrate));
169 ra->ra_raise_interval = msecs_to_ticks(interval);
170 }
171
172 static void
rssadapt_node_init(struct ieee80211_node * ni)173 rssadapt_node_init(struct ieee80211_node *ni)
174 {
175 struct ieee80211_rssadapt_node *ra;
176 struct ieee80211vap *vap = ni->ni_vap;
177 struct ieee80211_rssadapt *rsa = vap->iv_rs;
178 const struct ieee80211_rateset *rs = &ni->ni_rates;
179
180 if (!rsa) {
181 net80211_vap_printf(vap,
182 "ratectl structure was not allocated, "
183 "per-node structure allocation skipped\n");
184 return;
185 }
186
187 if (ni->ni_rctls == NULL) {
188 ni->ni_rctls = ra =
189 IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt_node),
190 M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
191 if (ra == NULL) {
192 net80211_vap_printf(vap,
193 "couldn't alloc per-node ratectl structure\n");
194 return;
195 }
196 } else
197 ra = ni->ni_rctls;
198 ra->ra_rs = rsa;
199 ra->ra_rates = *rs;
200 rssadapt_updatestats(ra);
201
202 /* pick initial rate */
203 for (ra->ra_rix = rs->rs_nrates - 1;
204 ra->ra_rix > 0 && (rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL) > 72;
205 ra->ra_rix--)
206 ;
207 ieee80211_node_set_txrate_dot11rate(ni,
208 rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL);
209 ra->ra_ticks = ticks;
210
211 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
212 "RSSADAPT initial rate %d Mbit/s",
213 ieee80211_node_get_txrate_kbit(ni) / 1000);
214 }
215
216 static void
rssadapt_node_deinit(struct ieee80211_node * ni)217 rssadapt_node_deinit(struct ieee80211_node *ni)
218 {
219
220 IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
221 }
222
223 static __inline int
bucket(int pktlen)224 bucket(int pktlen)
225 {
226 int i, top, thridx;
227
228 for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
229 i < IEEE80211_RSSADAPT_BKTS;
230 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
231 thridx = i;
232 if (pktlen <= top)
233 break;
234 }
235 return thridx;
236 }
237
238 static int
rssadapt_rate(struct ieee80211_node * ni,void * arg __unused,uint32_t iarg)239 rssadapt_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg)
240 {
241 struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
242 u_int pktlen = iarg;
243 const struct ieee80211_rateset *rs;
244 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
245 int rix, rssi;
246
247 /* XXX should return -1 here, but drivers may not expect this... */
248 if (!ra)
249 {
250 ieee80211_node_set_txrate_dot11rate(ni,
251 ni->ni_rates.rs_rates[0]);
252 return 0;
253 }
254
255 rs = &ra->ra_rates;
256 if ((ticks - ra->ra_ticks) > ra->ra_rs->interval) {
257 rssadapt_updatestats(ra);
258 ra->ra_ticks = ticks;
259 }
260
261 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
262
263 /* XXX this is average rssi, should be using last value */
264 rssi = ni->ni_ic->ic_node_getrssi(ni);
265 for (rix = rs->rs_nrates-1; rix >= 0; rix--)
266 if ((*thrs)[rix] < (rssi << 8))
267 break;
268 if (rix != ra->ra_rix) {
269 /* update public rate */
270 ieee80211_node_set_txrate_dot11rate(ni,
271 ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL);
272 ra->ra_rix = rix;
273
274 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
275 "RSSADAPT new rate %d Mbit/s (pktlen %d rssi %d)",
276 ieee80211_node_get_txrate_kbit(ni) / 1000, pktlen, rssi);
277 }
278 return rix;
279 }
280
281 /*
282 * Adapt the data rate to suit the conditions. When a transmitted
283 * packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions,
284 * raise the RSS threshold for transmitting packets of similar length at
285 * the same data rate.
286 */
287 static void
rssadapt_lower_rate(struct ieee80211_rssadapt_node * ra,int pktlen,int rssi)288 rssadapt_lower_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
289 {
290 uint16_t last_thr;
291 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
292 u_int rix;
293
294 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
295
296 rix = ra->ra_rix;
297 last_thr = (*thrs)[rix];
298 (*thrs)[rix] = interpolate(master_expavgctl.rc_thresh,
299 last_thr, (rssi << 8));
300
301 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
302 "RSSADAPT lower threshold for rate %d (last_thr %d new thr %d rssi %d)\n",
303 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
304 last_thr, (*thrs)[rix], rssi);
305 }
306
307 static void
rssadapt_raise_rate(struct ieee80211_rssadapt_node * ra,int pktlen,int rssi)308 rssadapt_raise_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
309 {
310 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
311 uint16_t newthr, oldthr;
312 int rix;
313
314 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
315
316 rix = ra->ra_rix;
317 if ((*thrs)[rix + 1] > (*thrs)[rix]) {
318 oldthr = (*thrs)[rix + 1];
319 if ((*thrs)[rix] == 0)
320 newthr = (rssi << 8);
321 else
322 newthr = (*thrs)[rix];
323 (*thrs)[rix + 1] = interpolate(master_expavgctl.rc_decay,
324 oldthr, newthr);
325
326 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
327 "RSSADAPT raise threshold for rate %d (oldthr %d newthr %d rssi %d)\n",
328 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
329 oldthr, newthr, rssi);
330
331 ra->ra_last_raise = ticks;
332 }
333 }
334
335 static void
rssadapt_tx_complete(const struct ieee80211_node * ni,const struct ieee80211_ratectl_tx_status * status)336 rssadapt_tx_complete(const struct ieee80211_node *ni,
337 const struct ieee80211_ratectl_tx_status *status)
338 {
339 struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
340 int pktlen, rssi;
341
342 if (!ra)
343 return;
344
345 if ((status->flags &
346 (IEEE80211_RATECTL_STATUS_PKTLEN|IEEE80211_RATECTL_STATUS_RSSI)) !=
347 (IEEE80211_RATECTL_STATUS_PKTLEN|IEEE80211_RATECTL_STATUS_RSSI))
348 return;
349
350 pktlen = status->pktlen;
351 rssi = status->rssi;
352
353 if (status->status == IEEE80211_RATECTL_TX_SUCCESS) {
354 ra->ra_nok++;
355 if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates &&
356 (ticks - ra->ra_last_raise) >= ra->ra_raise_interval)
357 rssadapt_raise_rate(ra, pktlen, rssi);
358 } else {
359 ra->ra_nfail++;
360 rssadapt_lower_rate(ra, pktlen, rssi);
361 }
362 }
363
364 static int
rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS)365 rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS)
366 {
367 struct ieee80211vap *vap = arg1;
368 struct ieee80211_rssadapt *rs = vap->iv_rs;
369 int msecs, error;
370
371 if (!rs)
372 return ENOMEM;
373
374 msecs = ticks_to_msecs(rs->interval);
375 error = sysctl_handle_int(oidp, &msecs, 0, req);
376 if (error || !req->newptr)
377 return error;
378 rssadapt_setinterval(vap, msecs);
379 return 0;
380 }
381
382 static void
rssadapt_sysctlattach(struct ieee80211vap * vap,struct sysctl_ctx_list * ctx,struct sysctl_oid * tree)383 rssadapt_sysctlattach(struct ieee80211vap *vap,
384 struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
385 {
386
387 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
388 "rssadapt_rate_interval",
389 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, vap, 0,
390 rssadapt_sysctl_interval, "I", "rssadapt operation interval (ms)");
391 }
392