1 /* $FreeBSD: releng/11.2/sys/net80211/ieee80211_rssadapt.c 321724 2017-07-30 18:29:28Z 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/systm.h>
37 #include <sys/kernel.h>
38 #include <sys/malloc.h>
39 #include <sys/module.h>
40 #include <sys/socket.h>
41 #include <sys/sysctl.h>
42
43 #include <net/if.h>
44 #include <net/if_var.h>
45 #include <net/if_media.h>
46 #include <net/ethernet.h>
47
48 #include <net80211/ieee80211_var.h>
49 #include <net80211/ieee80211_rssadapt.h>
50 #include <net80211/ieee80211_ratectl.h>
51
52 struct rssadapt_expavgctl {
53 /* RSS threshold decay. */
54 u_int rc_decay_denom;
55 u_int rc_decay_old;
56 /* RSS threshold update. */
57 u_int rc_thresh_denom;
58 u_int rc_thresh_old;
59 /* RSS average update. */
60 u_int rc_avgrssi_denom;
61 u_int rc_avgrssi_old;
62 };
63
64 static struct rssadapt_expavgctl master_expavgctl = {
65 .rc_decay_denom = 16,
66 .rc_decay_old = 15,
67 .rc_thresh_denom = 8,
68 .rc_thresh_old = 4,
69 .rc_avgrssi_denom = 8,
70 .rc_avgrssi_old = 4
71 };
72
73 #ifdef interpolate
74 #undef interpolate
75 #endif
76 #define interpolate(parm, old, new) ((parm##_old * (old) + \
77 (parm##_denom - parm##_old) * (new)) / \
78 parm##_denom)
79
80 static void rssadapt_setinterval(const struct ieee80211vap *, int);
81 static void rssadapt_init(struct ieee80211vap *);
82 static void rssadapt_deinit(struct ieee80211vap *);
83 static void rssadapt_updatestats(struct ieee80211_rssadapt_node *);
84 static void rssadapt_node_init(struct ieee80211_node *);
85 static void rssadapt_node_deinit(struct ieee80211_node *);
86 static int rssadapt_rate(struct ieee80211_node *, void *, uint32_t);
87 static void rssadapt_lower_rate(struct ieee80211_rssadapt_node *, int, int);
88 static void rssadapt_raise_rate(struct ieee80211_rssadapt_node *,
89 int, int);
90 static void rssadapt_tx_complete(const struct ieee80211vap *,
91 const struct ieee80211_node *, int,
92 void *, void *);
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
116 rssadapt_setinterval(const struct ieee80211vap *vap, int msecs)
117 {
118 struct ieee80211_rssadapt *rs = vap->iv_rs;
119 int t;
120
121 if (msecs < 100)
122 msecs = 100;
123 t = msecs_to_ticks(msecs);
124 rs->interval = (t < 1) ? 1 : t;
125 }
126
127 static void
128 rssadapt_init(struct ieee80211vap *vap)
129 {
130 struct ieee80211_rssadapt *rs;
131
132 KASSERT(vap->iv_rs == NULL, ("%s: iv_rs already initialized",
133 __func__));
134
135 nrefs++; /* XXX locking */
136 vap->iv_rs = rs = IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt),
137 M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
138 if (rs == NULL) {
139 if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
140 return;
141 }
142 rs->vap = vap;
143 rssadapt_setinterval(vap, 500 /* msecs */);
144 rssadapt_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
145 }
146
147 static void
148 rssadapt_deinit(struct ieee80211vap *vap)
149 {
150 IEEE80211_FREE(vap->iv_rs, M_80211_RATECTL);
151 KASSERT(nrefs > 0, ("imbalanced attach/detach"));
152 nrefs--; /* XXX locking */
153 }
154
155 static void
156 rssadapt_updatestats(struct ieee80211_rssadapt_node *ra)
157 {
158 long interval;
159
160 ra->ra_pktrate = (ra->ra_pktrate + 10*(ra->ra_nfail + ra->ra_nok))/2;
161 ra->ra_nfail = ra->ra_nok = 0;
162
163 /*
164 * A node is eligible for its rate to be raised every 1/10 to 10
165 * seconds, more eligible in proportion to recent packet rates.
166 */
167 interval = MAX(10*1000, 10*1000 / MAX(1, 10 * ra->ra_pktrate));
168 ra->ra_raise_interval = msecs_to_ticks(interval);
169 }
170
171 static void
172 rssadapt_node_init(struct ieee80211_node *ni)
173 {
174 struct ieee80211_rssadapt_node *ra;
175 struct ieee80211vap *vap = ni->ni_vap;
176 struct ieee80211_rssadapt *rsa = vap->iv_rs;
177 const struct ieee80211_rateset *rs = &ni->ni_rates;
178
179 if (ni->ni_rctls == NULL) {
180 ni->ni_rctls = ra =
181 IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt_node),
182 M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
183 if (ra == NULL) {
184 if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
185 "structure\n");
186 return;
187 }
188 } else
189 ra = ni->ni_rctls;
190 ra->ra_rs = rsa;
191 ra->ra_rates = *rs;
192 rssadapt_updatestats(ra);
193
194 /* pick initial rate */
195 for (ra->ra_rix = rs->rs_nrates - 1;
196 ra->ra_rix > 0 && (rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL) > 72;
197 ra->ra_rix--)
198 ;
199 ni->ni_txrate = rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL;
200 ra->ra_ticks = ticks;
201
202 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
203 "RSSADAPT initial rate %d", ni->ni_txrate);
204 }
205
206 static void
207 rssadapt_node_deinit(struct ieee80211_node *ni)
208 {
209
210 IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
211 }
212
213 static __inline int
214 bucket(int pktlen)
215 {
216 int i, top, thridx;
217
218 for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
219 i < IEEE80211_RSSADAPT_BKTS;
220 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
221 thridx = i;
222 if (pktlen <= top)
223 break;
224 }
225 return thridx;
226 }
227
228 static int
229 rssadapt_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg)
230 {
231 struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
232 u_int pktlen = iarg;
233 const struct ieee80211_rateset *rs = &ra->ra_rates;
234 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
235 int rix, rssi;
236
237 if ((ticks - ra->ra_ticks) > ra->ra_rs->interval) {
238 rssadapt_updatestats(ra);
239 ra->ra_ticks = ticks;
240 }
241
242 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
243
244 /* XXX this is average rssi, should be using last value */
245 rssi = ni->ni_ic->ic_node_getrssi(ni);
246 for (rix = rs->rs_nrates-1; rix >= 0; rix--)
247 if ((*thrs)[rix] < (rssi << 8))
248 break;
249 if (rix != ra->ra_rix) {
250 /* update public rate */
251 ni->ni_txrate = ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
252 ra->ra_rix = rix;
253
254 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
255 "RSSADAPT new rate %d (pktlen %d rssi %d)",
256 ni->ni_txrate, pktlen, rssi);
257 }
258 return rix;
259 }
260
261 /*
262 * Adapt the data rate to suit the conditions. When a transmitted
263 * packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions,
264 * raise the RSS threshold for transmitting packets of similar length at
265 * the same data rate.
266 */
267 static void
268 rssadapt_lower_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
269 {
270 uint16_t last_thr;
271 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
272 u_int rix;
273
274 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
275
276 rix = ra->ra_rix;
277 last_thr = (*thrs)[rix];
278 (*thrs)[rix] = interpolate(master_expavgctl.rc_thresh,
279 last_thr, (rssi << 8));
280
281 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
282 "RSSADAPT lower threshold for rate %d (last_thr %d new thr %d rssi %d)\n",
283 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
284 last_thr, (*thrs)[rix], rssi);
285 }
286
287 static void
288 rssadapt_raise_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
289 {
290 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
291 uint16_t newthr, oldthr;
292 int rix;
293
294 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
295
296 rix = ra->ra_rix;
297 if ((*thrs)[rix + 1] > (*thrs)[rix]) {
298 oldthr = (*thrs)[rix + 1];
299 if ((*thrs)[rix] == 0)
300 newthr = (rssi << 8);
301 else
302 newthr = (*thrs)[rix];
303 (*thrs)[rix + 1] = interpolate(master_expavgctl.rc_decay,
304 oldthr, newthr);
305
306 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
307 "RSSADAPT raise threshold for rate %d (oldthr %d newthr %d rssi %d)\n",
308 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
309 oldthr, newthr, rssi);
310
311 ra->ra_last_raise = ticks;
312 }
313 }
314
315 static void
316 rssadapt_tx_complete(const struct ieee80211vap *vap,
317 const struct ieee80211_node *ni, int success, void *arg1, void *arg2)
318 {
319 struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
320 int pktlen = *(int *)arg1, rssi = *(int *)arg2;
321
322 if (success) {
323 ra->ra_nok++;
324 if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates &&
325 (ticks - ra->ra_last_raise) >= ra->ra_raise_interval)
326 rssadapt_raise_rate(ra, pktlen, rssi);
327 } else {
328 ra->ra_nfail++;
329 rssadapt_lower_rate(ra, pktlen, rssi);
330 }
331 }
332
333 static int
334 rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS)
335 {
336 struct ieee80211vap *vap = arg1;
337 struct ieee80211_rssadapt *rs = vap->iv_rs;
338 int msecs = ticks_to_msecs(rs->interval);
339 int error;
340
341 error = sysctl_handle_int(oidp, &msecs, 0, req);
342 if (error || !req->newptr)
343 return error;
344 rssadapt_setinterval(vap, msecs);
345 return 0;
346 }
347
348 static void
349 rssadapt_sysctlattach(struct ieee80211vap *vap,
350 struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
351 {
352
353 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
354 "rssadapt_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
355 0, rssadapt_sysctl_interval, "I", "rssadapt operation interval (ms)");
356 }
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