1 /* $FreeBSD: releng/8.1/sys/net80211/ieee80211_rssadapt.c 207912 2010-05-11 11:08:15Z rpaulo $ */
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 vap->iv_rs = rs = malloc(sizeof(struct ieee80211_rssadapt),
132 M_80211_RATECTL, M_NOWAIT|M_ZERO);
133 if (rs == NULL) {
134 if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
135 return;
136 }
137 rs->vap = vap;
138 rssadapt_setinterval(vap, 500 /* msecs */);
139 rssadapt_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
140 }
141
142 static void
143 rssadapt_deinit(struct ieee80211vap *vap)
144 {
145 free(vap->iv_rs, M_80211_RATECTL);
146 }
147
148 static void
149 rssadapt_updatestats(struct ieee80211_rssadapt_node *ra)
150 {
151 long interval;
152
153 ra->ra_pktrate = (ra->ra_pktrate + 10*(ra->ra_nfail + ra->ra_nok))/2;
154 ra->ra_nfail = ra->ra_nok = 0;
155
156 /*
157 * A node is eligible for its rate to be raised every 1/10 to 10
158 * seconds, more eligible in proportion to recent packet rates.
159 */
160 interval = MAX(10*1000, 10*1000 / MAX(1, 10 * ra->ra_pktrate));
161 ra->ra_raise_interval = msecs_to_ticks(interval);
162 }
163
164 static void
165 rssadapt_node_init(struct ieee80211_node *ni)
166 {
167 struct ieee80211_rssadapt_node *ra;
168 struct ieee80211vap *vap = ni->ni_vap;
169 struct ieee80211_rssadapt *rsa = vap->iv_rs;
170 const struct ieee80211_rateset *rs = &ni->ni_rates;
171
172 ni->ni_rctls = ra = malloc(sizeof(struct ieee80211_rssadapt_node),
173 M_80211_RATECTL, M_NOWAIT|M_ZERO);
174 if (ra == NULL) {
175 if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
176 "structure\n");
177 return;
178 }
179 ra->ra_rs = rsa;
180 ra->ra_rates = *rs;
181 rssadapt_updatestats(ra);
182
183 /* pick initial rate */
184 for (ra->ra_rix = rs->rs_nrates - 1;
185 ra->ra_rix > 0 && (rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL) > 72;
186 ra->ra_rix--)
187 ;
188 ni->ni_txrate = rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL;
189 ra->ra_ticks = ticks;
190
191 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
192 "RSSADAPT initial rate %d", ni->ni_txrate);
193 }
194
195 static void
196 rssadapt_node_deinit(struct ieee80211_node *ni)
197 {
198
199 free(ni->ni_rctls, M_80211_RATECTL);
200 }
201
202 static __inline int
203 bucket(int pktlen)
204 {
205 int i, top, thridx;
206
207 for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
208 i < IEEE80211_RSSADAPT_BKTS;
209 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
210 thridx = i;
211 if (pktlen <= top)
212 break;
213 }
214 return thridx;
215 }
216
217 static int
218 rssadapt_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg)
219 {
220 struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
221 u_int pktlen = iarg;
222 const struct ieee80211_rateset *rs = &ra->ra_rates;
223 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
224 int rix, rssi;
225
226 if ((ticks - ra->ra_ticks) > ra->ra_rs->interval) {
227 rssadapt_updatestats(ra);
228 ra->ra_ticks = ticks;
229 }
230
231 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
232
233 /* XXX this is average rssi, should be using last value */
234 rssi = ni->ni_ic->ic_node_getrssi(ni);
235 for (rix = rs->rs_nrates-1; rix >= 0; rix--)
236 if ((*thrs)[rix] < (rssi << 8))
237 break;
238 if (rix != ra->ra_rix) {
239 /* update public rate */
240 ni->ni_txrate = ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
241 ra->ra_rix = rix;
242
243 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
244 "RSSADAPT new rate %d (pktlen %d rssi %d)",
245 ni->ni_txrate, pktlen, rssi);
246 }
247 return rix;
248 }
249
250 /*
251 * Adapt the data rate to suit the conditions. When a transmitted
252 * packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions,
253 * raise the RSS threshold for transmitting packets of similar length at
254 * the same data rate.
255 */
256 static void
257 rssadapt_lower_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
258 {
259 uint16_t last_thr;
260 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
261 u_int rix;
262
263 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
264
265 rix = ra->ra_rix;
266 last_thr = (*thrs)[rix];
267 (*thrs)[rix] = interpolate(master_expavgctl.rc_thresh,
268 last_thr, (rssi << 8));
269
270 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
271 "RSSADAPT lower threshold for rate %d (last_thr %d new thr %d rssi %d)\n",
272 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
273 last_thr, (*thrs)[rix], rssi);
274 }
275
276 static void
277 rssadapt_raise_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
278 {
279 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
280 uint16_t newthr, oldthr;
281 int rix;
282
283 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
284
285 rix = ra->ra_rix;
286 if ((*thrs)[rix + 1] > (*thrs)[rix]) {
287 oldthr = (*thrs)[rix + 1];
288 if ((*thrs)[rix] == 0)
289 newthr = (rssi << 8);
290 else
291 newthr = (*thrs)[rix];
292 (*thrs)[rix + 1] = interpolate(master_expavgctl.rc_decay,
293 oldthr, newthr);
294
295 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
296 "RSSADAPT raise threshold for rate %d (oldthr %d newthr %d rssi %d)\n",
297 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
298 oldthr, newthr, rssi);
299
300 ra->ra_last_raise = ticks;
301 }
302 }
303
304 static void
305 rssadapt_tx_complete(const struct ieee80211vap *vap,
306 const struct ieee80211_node *ni, int success, void *arg1, void *arg2)
307 {
308 struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
309 int pktlen = *(int *)arg1, rssi = *(int *)arg2;
310
311 if (success) {
312 ra->ra_nok++;
313 if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates &&
314 (ticks - ra->ra_last_raise) >= ra->ra_raise_interval)
315 rssadapt_raise_rate(ra, pktlen, rssi);
316 } else {
317 ra->ra_nfail++;
318 rssadapt_lower_rate(ra, pktlen, rssi);
319 }
320 }
321
322 static int
323 rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS)
324 {
325 struct ieee80211vap *vap = arg1;
326 struct ieee80211_rssadapt *rs = vap->iv_rs;
327 int msecs = ticks_to_msecs(rs->interval);
328 int error;
329
330 error = sysctl_handle_int(oidp, &msecs, 0, req);
331 if (error || !req->newptr)
332 return error;
333 rssadapt_setinterval(vap, msecs);
334 return 0;
335 }
336
337 static void
338 rssadapt_sysctlattach(struct ieee80211vap *vap,
339 struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
340 {
341
342 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
343 "rssadapt_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
344 0, rssadapt_sysctl_interval, "I", "rssadapt operation interval (ms)");
345 }
Cache object: 224587a69f316de44a3d45c30b872f11
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