1 /* $FreeBSD$ */
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 (!rs)
122 return;
123
124 if (msecs < 100)
125 msecs = 100;
126 t = msecs_to_ticks(msecs);
127 rs->interval = (t < 1) ? 1 : t;
128 }
129
130 static void
131 rssadapt_init(struct ieee80211vap *vap)
132 {
133 struct ieee80211_rssadapt *rs;
134
135 KASSERT(vap->iv_rs == NULL, ("%s: iv_rs already initialized",
136 __func__));
137
138 nrefs++; /* XXX locking */
139 vap->iv_rs = rs = IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt),
140 M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
141 if (rs == NULL) {
142 if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
143 return;
144 }
145 rs->vap = vap;
146 rssadapt_setinterval(vap, 500 /* msecs */);
147 rssadapt_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
148 }
149
150 static void
151 rssadapt_deinit(struct ieee80211vap *vap)
152 {
153 IEEE80211_FREE(vap->iv_rs, M_80211_RATECTL);
154 KASSERT(nrefs > 0, ("imbalanced attach/detach"));
155 nrefs--; /* XXX locking */
156 }
157
158 static void
159 rssadapt_updatestats(struct ieee80211_rssadapt_node *ra)
160 {
161 long interval;
162
163 ra->ra_pktrate = (ra->ra_pktrate + 10*(ra->ra_nfail + ra->ra_nok))/2;
164 ra->ra_nfail = ra->ra_nok = 0;
165
166 /*
167 * A node is eligible for its rate to be raised every 1/10 to 10
168 * seconds, more eligible in proportion to recent packet rates.
169 */
170 interval = MAX(10*1000, 10*1000 / MAX(1, 10 * ra->ra_pktrate));
171 ra->ra_raise_interval = msecs_to_ticks(interval);
172 }
173
174 static void
175 rssadapt_node_init(struct ieee80211_node *ni)
176 {
177 struct ieee80211_rssadapt_node *ra;
178 struct ieee80211vap *vap = ni->ni_vap;
179 struct ieee80211_rssadapt *rsa = vap->iv_rs;
180 const struct ieee80211_rateset *rs = &ni->ni_rates;
181
182 if (!rsa) {
183 if_printf(vap->iv_ifp, "ratectl structure was not allocated, "
184 "per-node structure allocation skipped\n");
185 return;
186 }
187
188 if (ni->ni_rctls == NULL) {
189 ni->ni_rctls = ra =
190 IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt_node),
191 M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
192 if (ra == NULL) {
193 if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
194 "structure\n");
195 return;
196 }
197 } else
198 ra = ni->ni_rctls;
199 ra->ra_rs = rsa;
200 ra->ra_rates = *rs;
201 rssadapt_updatestats(ra);
202
203 /* pick initial rate */
204 for (ra->ra_rix = rs->rs_nrates - 1;
205 ra->ra_rix > 0 && (rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL) > 72;
206 ra->ra_rix--)
207 ;
208 ni->ni_txrate = 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", ni->ni_txrate);
213 }
214
215 static void
216 rssadapt_node_deinit(struct ieee80211_node *ni)
217 {
218
219 IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
220 }
221
222 static __inline int
223 bucket(int pktlen)
224 {
225 int i, top, thridx;
226
227 for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
228 i < IEEE80211_RSSADAPT_BKTS;
229 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
230 thridx = i;
231 if (pktlen <= top)
232 break;
233 }
234 return thridx;
235 }
236
237 static int
238 rssadapt_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg)
239 {
240 struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
241 u_int pktlen = iarg;
242 const struct ieee80211_rateset *rs;
243 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
244 int rix, rssi;
245
246 /* XXX should return -1 here, but drivers may not expect this... */
247 if (!ra)
248 {
249 ni->ni_txrate = ni->ni_rates.rs_rates[0];
250 return 0;
251 }
252
253 rs = &ra->ra_rates;
254 if ((ticks - ra->ra_ticks) > ra->ra_rs->interval) {
255 rssadapt_updatestats(ra);
256 ra->ra_ticks = ticks;
257 }
258
259 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
260
261 /* XXX this is average rssi, should be using last value */
262 rssi = ni->ni_ic->ic_node_getrssi(ni);
263 for (rix = rs->rs_nrates-1; rix >= 0; rix--)
264 if ((*thrs)[rix] < (rssi << 8))
265 break;
266 if (rix != ra->ra_rix) {
267 /* update public rate */
268 ni->ni_txrate = ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
269 ra->ra_rix = rix;
270
271 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
272 "RSSADAPT new rate %d (pktlen %d rssi %d)",
273 ni->ni_txrate, pktlen, rssi);
274 }
275 return rix;
276 }
277
278 /*
279 * Adapt the data rate to suit the conditions. When a transmitted
280 * packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions,
281 * raise the RSS threshold for transmitting packets of similar length at
282 * the same data rate.
283 */
284 static void
285 rssadapt_lower_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
286 {
287 uint16_t last_thr;
288 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
289 u_int rix;
290
291 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
292
293 rix = ra->ra_rix;
294 last_thr = (*thrs)[rix];
295 (*thrs)[rix] = interpolate(master_expavgctl.rc_thresh,
296 last_thr, (rssi << 8));
297
298 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
299 "RSSADAPT lower threshold for rate %d (last_thr %d new thr %d rssi %d)\n",
300 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
301 last_thr, (*thrs)[rix], rssi);
302 }
303
304 static void
305 rssadapt_raise_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
306 {
307 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
308 uint16_t newthr, oldthr;
309 int rix;
310
311 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
312
313 rix = ra->ra_rix;
314 if ((*thrs)[rix + 1] > (*thrs)[rix]) {
315 oldthr = (*thrs)[rix + 1];
316 if ((*thrs)[rix] == 0)
317 newthr = (rssi << 8);
318 else
319 newthr = (*thrs)[rix];
320 (*thrs)[rix + 1] = interpolate(master_expavgctl.rc_decay,
321 oldthr, newthr);
322
323 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
324 "RSSADAPT raise threshold for rate %d (oldthr %d newthr %d rssi %d)\n",
325 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
326 oldthr, newthr, rssi);
327
328 ra->ra_last_raise = ticks;
329 }
330 }
331
332 static void
333 rssadapt_tx_complete(const struct ieee80211vap *vap,
334 const struct ieee80211_node *ni, int success, void *arg1, void *arg2)
335 {
336 struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
337 int pktlen = *(int *)arg1, rssi = *(int *)arg2;
338
339 if (!ra)
340 return;
341
342 if (success) {
343 ra->ra_nok++;
344 if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates &&
345 (ticks - ra->ra_last_raise) >= ra->ra_raise_interval)
346 rssadapt_raise_rate(ra, pktlen, rssi);
347 } else {
348 ra->ra_nfail++;
349 rssadapt_lower_rate(ra, pktlen, rssi);
350 }
351 }
352
353 static int
354 rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS)
355 {
356 struct ieee80211vap *vap = arg1;
357 struct ieee80211_rssadapt *rs = vap->iv_rs;
358 int msecs, error;
359
360 if (!rs)
361 return ENOMEM;
362
363 msecs = ticks_to_msecs(rs->interval);
364 error = sysctl_handle_int(oidp, &msecs, 0, req);
365 if (error || !req->newptr)
366 return error;
367 rssadapt_setinterval(vap, msecs);
368 return 0;
369 }
370
371 static void
372 rssadapt_sysctlattach(struct ieee80211vap *vap,
373 struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
374 {
375
376 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
377 "rssadapt_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
378 0, rssadapt_sysctl_interval, "I", "rssadapt operation interval (ms)");
379 }
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