1 /* $FreeBSD: releng/10.4/sys/net80211/ieee80211_rssadapt.c 321725 2017-07-30 18:38:05Z 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
112 rssadapt_setinterval(const struct ieee80211vap *vap, int msecs)
113 {
114 struct ieee80211_rssadapt *rs = vap->iv_rs;
115 int t;
116
117 if (msecs < 100)
118 msecs = 100;
119 t = msecs_to_ticks(msecs);
120 rs->interval = (t < 1) ? 1 : t;
121 }
122
123 static void
124 rssadapt_init(struct ieee80211vap *vap)
125 {
126 struct ieee80211_rssadapt *rs;
127
128 KASSERT(vap->iv_rs == NULL, ("%s: iv_rs already initialized",
129 __func__));
130
131 nrefs++; /* XXX locking */
132 vap->iv_rs = rs = malloc(sizeof(struct ieee80211_rssadapt),
133 M_80211_RATECTL, M_NOWAIT|M_ZERO);
134 if (rs == NULL) {
135 if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
136 return;
137 }
138 rs->vap = vap;
139 rssadapt_setinterval(vap, 500 /* msecs */);
140 rssadapt_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
141 }
142
143 static void
144 rssadapt_deinit(struct ieee80211vap *vap)
145 {
146 free(vap->iv_rs, M_80211_RATECTL);
147 KASSERT(nrefs > 0, ("imbalanced attach/detach"));
148 nrefs--; /* XXX locking */
149 }
150
151 static void
152 rssadapt_updatestats(struct ieee80211_rssadapt_node *ra)
153 {
154 long interval;
155
156 ra->ra_pktrate = (ra->ra_pktrate + 10*(ra->ra_nfail + ra->ra_nok))/2;
157 ra->ra_nfail = ra->ra_nok = 0;
158
159 /*
160 * A node is eligible for its rate to be raised every 1/10 to 10
161 * seconds, more eligible in proportion to recent packet rates.
162 */
163 interval = MAX(10*1000, 10*1000 / MAX(1, 10 * ra->ra_pktrate));
164 ra->ra_raise_interval = msecs_to_ticks(interval);
165 }
166
167 static void
168 rssadapt_node_init(struct ieee80211_node *ni)
169 {
170 struct ieee80211_rssadapt_node *ra;
171 struct ieee80211vap *vap = ni->ni_vap;
172 struct ieee80211_rssadapt *rsa = vap->iv_rs;
173 const struct ieee80211_rateset *rs = &ni->ni_rates;
174
175 if (ni->ni_rctls == NULL) {
176 ni->ni_rctls = ra =
177 malloc(sizeof(struct ieee80211_rssadapt_node),
178 M_80211_RATECTL, M_NOWAIT|M_ZERO);
179 if (ra == NULL) {
180 if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
181 "structure\n");
182 return;
183 }
184 } else
185 ra = ni->ni_rctls;
186 ra->ra_rs = rsa;
187 ra->ra_rates = *rs;
188 rssadapt_updatestats(ra);
189
190 /* pick initial rate */
191 for (ra->ra_rix = rs->rs_nrates - 1;
192 ra->ra_rix > 0 && (rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL) > 72;
193 ra->ra_rix--)
194 ;
195 ni->ni_txrate = rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL;
196 ra->ra_ticks = ticks;
197
198 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
199 "RSSADAPT initial rate %d", ni->ni_txrate);
200 }
201
202 static void
203 rssadapt_node_deinit(struct ieee80211_node *ni)
204 {
205
206 free(ni->ni_rctls, M_80211_RATECTL);
207 }
208
209 static __inline int
210 bucket(int pktlen)
211 {
212 int i, top, thridx;
213
214 for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
215 i < IEEE80211_RSSADAPT_BKTS;
216 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
217 thridx = i;
218 if (pktlen <= top)
219 break;
220 }
221 return thridx;
222 }
223
224 static int
225 rssadapt_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg)
226 {
227 struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
228 u_int pktlen = iarg;
229 const struct ieee80211_rateset *rs = &ra->ra_rates;
230 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
231 int rix, rssi;
232
233 if ((ticks - ra->ra_ticks) > ra->ra_rs->interval) {
234 rssadapt_updatestats(ra);
235 ra->ra_ticks = ticks;
236 }
237
238 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
239
240 /* XXX this is average rssi, should be using last value */
241 rssi = ni->ni_ic->ic_node_getrssi(ni);
242 for (rix = rs->rs_nrates-1; rix >= 0; rix--)
243 if ((*thrs)[rix] < (rssi << 8))
244 break;
245 if (rix != ra->ra_rix) {
246 /* update public rate */
247 ni->ni_txrate = ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
248 ra->ra_rix = rix;
249
250 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
251 "RSSADAPT new rate %d (pktlen %d rssi %d)",
252 ni->ni_txrate, pktlen, rssi);
253 }
254 return rix;
255 }
256
257 /*
258 * Adapt the data rate to suit the conditions. When a transmitted
259 * packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions,
260 * raise the RSS threshold for transmitting packets of similar length at
261 * the same data rate.
262 */
263 static void
264 rssadapt_lower_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
265 {
266 uint16_t last_thr;
267 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
268 u_int rix;
269
270 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
271
272 rix = ra->ra_rix;
273 last_thr = (*thrs)[rix];
274 (*thrs)[rix] = interpolate(master_expavgctl.rc_thresh,
275 last_thr, (rssi << 8));
276
277 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
278 "RSSADAPT lower threshold for rate %d (last_thr %d new thr %d rssi %d)\n",
279 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
280 last_thr, (*thrs)[rix], rssi);
281 }
282
283 static void
284 rssadapt_raise_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
285 {
286 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
287 uint16_t newthr, oldthr;
288 int rix;
289
290 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
291
292 rix = ra->ra_rix;
293 if ((*thrs)[rix + 1] > (*thrs)[rix]) {
294 oldthr = (*thrs)[rix + 1];
295 if ((*thrs)[rix] == 0)
296 newthr = (rssi << 8);
297 else
298 newthr = (*thrs)[rix];
299 (*thrs)[rix + 1] = interpolate(master_expavgctl.rc_decay,
300 oldthr, newthr);
301
302 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
303 "RSSADAPT raise threshold for rate %d (oldthr %d newthr %d rssi %d)\n",
304 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
305 oldthr, newthr, rssi);
306
307 ra->ra_last_raise = ticks;
308 }
309 }
310
311 static void
312 rssadapt_tx_complete(const struct ieee80211vap *vap,
313 const struct ieee80211_node *ni, int success, void *arg1, void *arg2)
314 {
315 struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
316 int pktlen = *(int *)arg1, rssi = *(int *)arg2;
317
318 if (success) {
319 ra->ra_nok++;
320 if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates &&
321 (ticks - ra->ra_last_raise) >= ra->ra_raise_interval)
322 rssadapt_raise_rate(ra, pktlen, rssi);
323 } else {
324 ra->ra_nfail++;
325 rssadapt_lower_rate(ra, pktlen, rssi);
326 }
327 }
328
329 static int
330 rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS)
331 {
332 struct ieee80211vap *vap = arg1;
333 struct ieee80211_rssadapt *rs = vap->iv_rs;
334 int msecs = ticks_to_msecs(rs->interval);
335 int error;
336
337 error = sysctl_handle_int(oidp, &msecs, 0, req);
338 if (error || !req->newptr)
339 return error;
340 rssadapt_setinterval(vap, msecs);
341 return 0;
342 }
343
344 static void
345 rssadapt_sysctlattach(struct ieee80211vap *vap,
346 struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
347 {
348
349 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
350 "rssadapt_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
351 0, rssadapt_sysctl_interval, "I", "rssadapt operation interval (ms)");
352 }
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