1 /* $FreeBSD: stable/10/sys/net80211/ieee80211_rssadapt.c 343036 2019-01-15 02:26:03Z avos $ */
2 /* $NetBSD: ieee80211_rssadapt.c,v 1.9 2005/02/26 22:45:09 perry Exp $ */
3 /*-
4 * Copyright (c) 2010 Rui Paulo <rpaulo@FreeBSD.org>
5 * Copyright (c) 2003, 2004 David Young. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or
8 * without modification, are permitted provided that the following
9 * conditions are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above
13 * copyright notice, this list of conditions and the following
14 * disclaimer in the documentation and/or other materials provided
15 * with the distribution.
16 * 3. The name of David Young may not be used to endorse or promote
17 * products derived from this software without specific prior
18 * written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY
21 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
22 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
23 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL David
24 * Young BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
26 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
28 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
31 * OF SUCH DAMAGE.
32 */
33 #include "opt_wlan.h"
34
35 #include <sys/param.h>
36 #include <sys/kernel.h>
37 #include <sys/module.h>
38 #include <sys/socket.h>
39 #include <sys/sysctl.h>
40
41 #include <net/if.h>
42 #include <net/if_media.h>
43
44 #include <net80211/ieee80211_var.h>
45 #include <net80211/ieee80211_rssadapt.h>
46 #include <net80211/ieee80211_ratectl.h>
47
48 struct rssadapt_expavgctl {
49 /* RSS threshold decay. */
50 u_int rc_decay_denom;
51 u_int rc_decay_old;
52 /* RSS threshold update. */
53 u_int rc_thresh_denom;
54 u_int rc_thresh_old;
55 /* RSS average update. */
56 u_int rc_avgrssi_denom;
57 u_int rc_avgrssi_old;
58 };
59
60 static struct rssadapt_expavgctl master_expavgctl = {
61 .rc_decay_denom = 16,
62 .rc_decay_old = 15,
63 .rc_thresh_denom = 8,
64 .rc_thresh_old = 4,
65 .rc_avgrssi_denom = 8,
66 .rc_avgrssi_old = 4
67 };
68
69 #ifdef interpolate
70 #undef interpolate
71 #endif
72 #define interpolate(parm, old, new) ((parm##_old * (old) + \
73 (parm##_denom - parm##_old) * (new)) / \
74 parm##_denom)
75
76 static void rssadapt_setinterval(const struct ieee80211vap *, int);
77 static void rssadapt_init(struct ieee80211vap *);
78 static void rssadapt_deinit(struct ieee80211vap *);
79 static void rssadapt_updatestats(struct ieee80211_rssadapt_node *);
80 static void rssadapt_node_init(struct ieee80211_node *);
81 static void rssadapt_node_deinit(struct ieee80211_node *);
82 static int rssadapt_rate(struct ieee80211_node *, void *, uint32_t);
83 static void rssadapt_lower_rate(struct ieee80211_rssadapt_node *, int, int);
84 static void rssadapt_raise_rate(struct ieee80211_rssadapt_node *,
85 int, int);
86 static void rssadapt_tx_complete(const struct ieee80211vap *,
87 const struct ieee80211_node *, int,
88 void *, void *);
89 static void rssadapt_sysctlattach(struct ieee80211vap *,
90 struct sysctl_ctx_list *, struct sysctl_oid *);
91
92 /* number of references from net80211 layer */
93 static int nrefs = 0;
94
95 static const struct ieee80211_ratectl rssadapt = {
96 .ir_name = "rssadapt",
97 .ir_attach = NULL,
98 .ir_detach = NULL,
99 .ir_init = rssadapt_init,
100 .ir_deinit = rssadapt_deinit,
101 .ir_node_init = rssadapt_node_init,
102 .ir_node_deinit = rssadapt_node_deinit,
103 .ir_rate = rssadapt_rate,
104 .ir_tx_complete = rssadapt_tx_complete,
105 .ir_tx_update = NULL,
106 .ir_setinterval = rssadapt_setinterval,
107 };
108 IEEE80211_RATECTL_MODULE(rssadapt, 1);
109 IEEE80211_RATECTL_ALG(rssadapt, IEEE80211_RATECTL_RSSADAPT, rssadapt);
110
111 static void
rssadapt_setinterval(const struct ieee80211vap * vap,int msecs)112 rssadapt_setinterval(const struct ieee80211vap *vap, int msecs)
113 {
114 struct ieee80211_rssadapt *rs = vap->iv_rs;
115 int t;
116
117 if (!rs)
118 return;
119
120 if (msecs < 100)
121 msecs = 100;
122 t = msecs_to_ticks(msecs);
123 rs->interval = (t < 1) ? 1 : t;
124 }
125
126 static void
rssadapt_init(struct ieee80211vap * vap)127 rssadapt_init(struct ieee80211vap *vap)
128 {
129 struct ieee80211_rssadapt *rs;
130
131 KASSERT(vap->iv_rs == NULL, ("%s: iv_rs already initialized",
132 __func__));
133
134 nrefs++; /* XXX locking */
135 vap->iv_rs = rs = malloc(sizeof(struct ieee80211_rssadapt),
136 M_80211_RATECTL, M_NOWAIT|M_ZERO);
137 if (rs == NULL) {
138 if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
139 return;
140 }
141 rs->vap = vap;
142 rssadapt_setinterval(vap, 500 /* msecs */);
143 rssadapt_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
144 }
145
146 static void
rssadapt_deinit(struct ieee80211vap * vap)147 rssadapt_deinit(struct ieee80211vap *vap)
148 {
149 free(vap->iv_rs, M_80211_RATECTL);
150 KASSERT(nrefs > 0, ("imbalanced attach/detach"));
151 nrefs--; /* XXX locking */
152 }
153
154 static void
rssadapt_updatestats(struct ieee80211_rssadapt_node * ra)155 rssadapt_updatestats(struct ieee80211_rssadapt_node *ra)
156 {
157 long interval;
158
159 ra->ra_pktrate = (ra->ra_pktrate + 10*(ra->ra_nfail + ra->ra_nok))/2;
160 ra->ra_nfail = ra->ra_nok = 0;
161
162 /*
163 * A node is eligible for its rate to be raised every 1/10 to 10
164 * seconds, more eligible in proportion to recent packet rates.
165 */
166 interval = MAX(10*1000, 10*1000 / MAX(1, 10 * ra->ra_pktrate));
167 ra->ra_raise_interval = msecs_to_ticks(interval);
168 }
169
170 static void
rssadapt_node_init(struct ieee80211_node * ni)171 rssadapt_node_init(struct ieee80211_node *ni)
172 {
173 struct ieee80211_rssadapt_node *ra;
174 struct ieee80211vap *vap = ni->ni_vap;
175 struct ieee80211_rssadapt *rsa = vap->iv_rs;
176 const struct ieee80211_rateset *rs = &ni->ni_rates;
177
178 if (!rsa) {
179 if_printf(vap->iv_ifp, "ratectl structure was not allocated, "
180 "per-node structure allocation skipped\n");
181 return;
182 }
183
184 if (ni->ni_rctls == NULL) {
185 ni->ni_rctls = ra =
186 malloc(sizeof(struct ieee80211_rssadapt_node),
187 M_80211_RATECTL, M_NOWAIT|M_ZERO);
188 if (ra == NULL) {
189 if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
190 "structure\n");
191 return;
192 }
193 } else
194 ra = ni->ni_rctls;
195 ra->ra_rs = rsa;
196 ra->ra_rates = *rs;
197 rssadapt_updatestats(ra);
198
199 /* pick initial rate */
200 for (ra->ra_rix = rs->rs_nrates - 1;
201 ra->ra_rix > 0 && (rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL) > 72;
202 ra->ra_rix--)
203 ;
204 ni->ni_txrate = rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL;
205 ra->ra_ticks = ticks;
206
207 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
208 "RSSADAPT initial rate %d", ni->ni_txrate);
209 }
210
211 static void
rssadapt_node_deinit(struct ieee80211_node * ni)212 rssadapt_node_deinit(struct ieee80211_node *ni)
213 {
214
215 free(ni->ni_rctls, M_80211_RATECTL);
216 }
217
218 static __inline int
bucket(int pktlen)219 bucket(int pktlen)
220 {
221 int i, top, thridx;
222
223 for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
224 i < IEEE80211_RSSADAPT_BKTS;
225 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
226 thridx = i;
227 if (pktlen <= top)
228 break;
229 }
230 return thridx;
231 }
232
233 static int
rssadapt_rate(struct ieee80211_node * ni,void * arg __unused,uint32_t iarg)234 rssadapt_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg)
235 {
236 struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
237 u_int pktlen = iarg;
238 const struct ieee80211_rateset *rs;
239 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
240 int rix, rssi;
241
242 /* XXX should return -1 here, but drivers may not expect this... */
243 if (!ra)
244 {
245 ni->ni_txrate = ni->ni_rates.rs_rates[0];
246 return 0;
247 }
248
249 rs = &ra->ra_rates;
250 if ((ticks - ra->ra_ticks) > ra->ra_rs->interval) {
251 rssadapt_updatestats(ra);
252 ra->ra_ticks = ticks;
253 }
254
255 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
256
257 /* XXX this is average rssi, should be using last value */
258 rssi = ni->ni_ic->ic_node_getrssi(ni);
259 for (rix = rs->rs_nrates-1; rix >= 0; rix--)
260 if ((*thrs)[rix] < (rssi << 8))
261 break;
262 if (rix != ra->ra_rix) {
263 /* update public rate */
264 ni->ni_txrate = ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
265 ra->ra_rix = rix;
266
267 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
268 "RSSADAPT new rate %d (pktlen %d rssi %d)",
269 ni->ni_txrate, pktlen, rssi);
270 }
271 return rix;
272 }
273
274 /*
275 * Adapt the data rate to suit the conditions. When a transmitted
276 * packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions,
277 * raise the RSS threshold for transmitting packets of similar length at
278 * the same data rate.
279 */
280 static void
rssadapt_lower_rate(struct ieee80211_rssadapt_node * ra,int pktlen,int rssi)281 rssadapt_lower_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
282 {
283 uint16_t last_thr;
284 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
285 u_int rix;
286
287 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
288
289 rix = ra->ra_rix;
290 last_thr = (*thrs)[rix];
291 (*thrs)[rix] = interpolate(master_expavgctl.rc_thresh,
292 last_thr, (rssi << 8));
293
294 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
295 "RSSADAPT lower threshold for rate %d (last_thr %d new thr %d rssi %d)\n",
296 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
297 last_thr, (*thrs)[rix], rssi);
298 }
299
300 static void
rssadapt_raise_rate(struct ieee80211_rssadapt_node * ra,int pktlen,int rssi)301 rssadapt_raise_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
302 {
303 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
304 uint16_t newthr, oldthr;
305 int rix;
306
307 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
308
309 rix = ra->ra_rix;
310 if ((*thrs)[rix + 1] > (*thrs)[rix]) {
311 oldthr = (*thrs)[rix + 1];
312 if ((*thrs)[rix] == 0)
313 newthr = (rssi << 8);
314 else
315 newthr = (*thrs)[rix];
316 (*thrs)[rix + 1] = interpolate(master_expavgctl.rc_decay,
317 oldthr, newthr);
318
319 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
320 "RSSADAPT raise threshold for rate %d (oldthr %d newthr %d rssi %d)\n",
321 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
322 oldthr, newthr, rssi);
323
324 ra->ra_last_raise = ticks;
325 }
326 }
327
328 static void
rssadapt_tx_complete(const struct ieee80211vap * vap,const struct ieee80211_node * ni,int success,void * arg1,void * arg2)329 rssadapt_tx_complete(const struct ieee80211vap *vap,
330 const struct ieee80211_node *ni, int success, void *arg1, void *arg2)
331 {
332 struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
333 int pktlen = *(int *)arg1, rssi = *(int *)arg2;
334
335 if (!ra)
336 return;
337
338 if (success) {
339 ra->ra_nok++;
340 if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates &&
341 (ticks - ra->ra_last_raise) >= ra->ra_raise_interval)
342 rssadapt_raise_rate(ra, pktlen, rssi);
343 } else {
344 ra->ra_nfail++;
345 rssadapt_lower_rate(ra, pktlen, rssi);
346 }
347 }
348
349 static int
rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS)350 rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS)
351 {
352 struct ieee80211vap *vap = arg1;
353 struct ieee80211_rssadapt *rs = vap->iv_rs;
354 int msecs, error;
355
356 if (!rs)
357 return ENOMEM;
358
359 msecs = ticks_to_msecs(rs->interval);
360 error = sysctl_handle_int(oidp, &msecs, 0, req);
361 if (error || !req->newptr)
362 return error;
363 rssadapt_setinterval(vap, msecs);
364 return 0;
365 }
366
367 static void
rssadapt_sysctlattach(struct ieee80211vap * vap,struct sysctl_ctx_list * ctx,struct sysctl_oid * tree)368 rssadapt_sysctlattach(struct ieee80211vap *vap,
369 struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
370 {
371
372 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
373 "rssadapt_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
374 0, rssadapt_sysctl_interval, "I", "rssadapt operation interval (ms)");
375 }
376