1 /* $NetBSD: ieee80211_rssadapt.c,v 1.9 2005/02/26 22:45:09 perry Exp $ */
2 /*-
3 * Copyright (c) 2003, 2004 David Young. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or
6 * without modification, are permitted provided that the following
7 * conditions are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following
12 * disclaimer in the documentation and/or other materials provided
13 * with the distribution.
14 * 3. The name of David Young may not be used to endorse or promote
15 * products derived from this software without specific prior
16 * written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY
19 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
20 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
21 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL David
22 * Young BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
23 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
24 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
26 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
27 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
29 * OF SUCH DAMAGE.
30 */
31
32 #include <sys/param.h>
33 #include <sys/types.h>
34 #include <sys/kernel.h> /* for hz */
35 #include <sys/sysctl.h>
36
37 #include <net/if.h>
38 #include <net/if_media.h>
39 #include <net/if_ether.h>
40
41 #include <net80211/ieee80211_var.h>
42 #include <net80211/ieee80211.h>
43 #include <net80211/ieee80211_compat.h>
44 #include <net80211/ieee80211_rssadapt.h>
45
46 #ifdef interpolate
47 #undef interpolate
48 #endif
49 #define interpolate(parm, old, new) ((parm##_old * (old) + \
50 (parm##_denom - parm##_old) * (new)) / \
51 parm##_denom)
52
53 #ifdef IEEE80211_DEBUG
54 static struct timeval lastrateadapt; /* time of last rate adaptation msg */
55 static int currssadaptps = 0; /* rate-adaptation msgs this second */
56 static int ieee80211_adaptrate = 4; /* rate-adaptation max msgs/sec */
57
58 #define RSSADAPT_DO_PRINT() \
59 ((ieee80211_rssadapt_debug > 0) && \
60 ppsratecheck(&lastrateadapt, &currssadaptps, ieee80211_adaptrate))
61 #define RSSADAPT_PRINTF(X) \
62 if (RSSADAPT_DO_PRINT()) \
63 printf X
64
65 int ieee80211_rssadapt_debug = 0;
66
67 #else
68 #define RSSADAPT_DO_PRINT() (0)
69 #define RSSADAPT_PRINTF(X)
70 #endif
71
72 static struct ieee80211_rssadapt_expavgctl master_expavgctl = {
73 rc_decay_denom : 16,
74 rc_decay_old : 15,
75 rc_thresh_denom : 8,
76 rc_thresh_old : 4,
77 rc_avgrssi_denom : 8,
78 rc_avgrssi_old : 4
79 };
80
81 #ifdef __NetBSD__
82 #ifdef IEEE80211_DEBUG
83 /* TBD factor with sysctl_ath_verify, sysctl_ieee80211_verify. */
84 static int
85 sysctl_ieee80211_rssadapt_debug(SYSCTLFN_ARGS)
86 {
87 int error, t;
88 struct sysctlnode node;
89
90 node = *rnode;
91 t = *(int*)rnode->sysctl_data;
92 node.sysctl_data = &t;
93 error = sysctl_lookup(SYSCTLFN_CALL(&node));
94 if (error || newp == NULL)
95 return (error);
96
97 if (t < 0 || t > 2)
98 return (EINVAL);
99 *(int*)rnode->sysctl_data = t;
100
101 return (0);
102 }
103 #endif /* IEEE80211_DEBUG */
104
105 /* TBD factor with sysctl_ath_verify, sysctl_ieee80211_verify. */
106 static int
107 sysctl_ieee80211_rssadapt_expavgctl(SYSCTLFN_ARGS)
108 {
109 struct ieee80211_rssadapt_expavgctl rc;
110 int error;
111 struct sysctlnode node;
112
113 node = *rnode;
114 rc = *(struct ieee80211_rssadapt_expavgctl *)rnode->sysctl_data;
115 node.sysctl_data = &rc;
116 error = sysctl_lookup(SYSCTLFN_CALL(&node));
117 if (error || newp == NULL)
118 return (error);
119
120 if (rc.rc_decay_old < 0 ||
121 rc.rc_decay_denom < rc.rc_decay_old)
122 return (EINVAL);
123
124 if (rc.rc_thresh_old < 0 ||
125 rc.rc_thresh_denom < rc.rc_thresh_old)
126 return (EINVAL);
127
128 if (rc.rc_avgrssi_old < 0 ||
129 rc.rc_avgrssi_denom < rc.rc_avgrssi_old)
130 return (EINVAL);
131
132 *(struct ieee80211_rssadapt_expavgctl *)rnode->sysctl_data = rc;
133
134 return (0);
135 }
136
137 /*
138 * Setup sysctl(3) MIB, net.ieee80211.*
139 *
140 * TBD condition CTLFLAG_PERMANENT on being an LKM or not
141 */
142 SYSCTL_SETUP(sysctl_ieee80211_rssadapt,
143 "sysctl ieee80211 rssadapt subtree setup")
144 {
145 int rc;
146 struct sysctlnode *node;
147
148 if ((rc = sysctl_createv(clog, 0, NULL, &node,
149 CTLFLAG_PERMANENT, CTLTYPE_NODE, "net", NULL,
150 NULL, 0, NULL, 0, CTL_NET, CTL_EOL)) != 0)
151 goto err;
152
153 if ((rc = sysctl_createv(clog, 0, &node, &node,
154 CTLFLAG_PERMANENT, CTLTYPE_NODE, "link", NULL,
155 NULL, 0, NULL, 0, PF_LINK, CTL_EOL)) != 0)
156 goto err;
157
158 if ((rc = sysctl_createv(clog, 0, &node, &node,
159 CTLFLAG_PERMANENT, CTLTYPE_NODE, "ieee80211", NULL,
160 NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL)) != 0)
161 goto err;
162
163 if ((rc = sysctl_createv(clog, 0, &node, &node,
164 CTLFLAG_PERMANENT, CTLTYPE_NODE, "rssadapt",
165 SYSCTL_DESCR("Received Signal Strength adaptation controls"),
166 NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL)) != 0)
167 goto err;
168
169 #ifdef IEEE80211_DEBUG
170 /* control debugging printfs */
171 if ((rc = sysctl_createv(clog, 0, &node, NULL,
172 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "debug",
173 SYSCTL_DESCR("Enable RSS adaptation debugging output"),
174 sysctl_ieee80211_rssadapt_debug, 0, &ieee80211_rssadapt_debug, 0,
175 CTL_CREATE, CTL_EOL)) != 0)
176 goto err;
177 #endif /* IEEE80211_DEBUG */
178
179 /* control rate of decay for exponential averages */
180 if ((rc = sysctl_createv(clog, 0, &node, NULL,
181 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_STRUCT,
182 "expavgctl", SYSCTL_DESCR("RSS exponential averaging control"),
183 sysctl_ieee80211_rssadapt_expavgctl, 0,
184 &master_expavgctl, sizeof(master_expavgctl), CTL_CREATE,
185 CTL_EOL)) != 0)
186 goto err;
187
188 return;
189 err:
190 printf("%s: sysctl_createv failed (rc = %d)\n", __func__, rc);
191 }
192 #endif /* __NetBSD__ */
193
194 int
195 ieee80211_rssadapt_choose(struct ieee80211_rssadapt *ra,
196 struct ieee80211_rateset *rs, struct ieee80211_frame *wh, u_int len,
197 int fixed_rate, const char *dvname, int do_not_adapt)
198 {
199 u_int16_t (*thrs)[IEEE80211_RATE_SIZE];
200 int flags = 0, i, rateidx = 0, thridx, top;
201
202 if ((wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK) == IEEE80211_FC0_TYPE_CTL)
203 flags |= IEEE80211_RATE_BASIC;
204
205 for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
206 i < IEEE80211_RSSADAPT_BKTS;
207 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
208 thridx = i;
209 if (len <= top)
210 break;
211 }
212
213 thrs = &ra->ra_rate_thresh[thridx];
214
215 if (fixed_rate != -1) {
216 if ((rs->rs_rates[fixed_rate] & flags) == flags) {
217 rateidx = fixed_rate;
218 goto out;
219 }
220 flags |= IEEE80211_RATE_BASIC;
221 i = fixed_rate;
222 } else
223 i = rs->rs_nrates;
224
225 while (--i >= 0) {
226 rateidx = i;
227 if ((rs->rs_rates[i] & flags) != flags)
228 continue;
229 if (do_not_adapt)
230 break;
231 if ((*thrs)[i] < ra->ra_avg_rssi)
232 break;
233 }
234
235 out:
236 #ifdef IEEE80211_DEBUG
237 if (ieee80211_rssadapt_debug && dvname != NULL) {
238 printf("%s: dst %s threshold[%d, %d.%d] %d < %d\n",
239 dvname, ether_sprintf(wh->i_addr1), len,
240 (rs->rs_rates[rateidx] & IEEE80211_RATE_VAL) / 2,
241 (rs->rs_rates[rateidx] & IEEE80211_RATE_VAL) * 5 % 10,
242 (*thrs)[rateidx], ra->ra_avg_rssi);
243 }
244 #endif /* IEEE80211_DEBUG */
245 return rateidx;
246 }
247
248 void
249 ieee80211_rssadapt_updatestats(struct ieee80211_rssadapt *ra)
250 {
251 long interval;
252
253 ra->ra_pktrate =
254 (ra->ra_pktrate + 10 * (ra->ra_nfail + ra->ra_nok)) / 2;
255 ra->ra_nfail = ra->ra_nok = 0;
256
257 /* a node is eligible for its rate to be raised every 1/10 to 10
258 * seconds, more eligible in proportion to recent packet rates.
259 */
260 interval = MAX(100000, 10000000 / MAX(1, 10 * ra->ra_pktrate));
261 ra->ra_raise_interval.tv_sec = interval / (1000 * 1000);
262 ra->ra_raise_interval.tv_usec = interval % (1000 * 1000);
263 }
264
265 void
266 ieee80211_rssadapt_input(struct ieee80211com *ic, struct ieee80211_node *ni,
267 struct ieee80211_rssadapt *ra, int rssi)
268 {
269 #ifdef IEEE80211_DEBUG
270 int last_avg_rssi = ra->ra_avg_rssi;
271 #endif
272
273 ra->ra_avg_rssi = interpolate(master_expavgctl.rc_avgrssi,
274 ra->ra_avg_rssi, (rssi << 8));
275
276 RSSADAPT_PRINTF(("%s: src %s rssi %d avg %d -> %d\n",
277 ic->ic_if.if_xname, ether_sprintf(ni->ni_macaddr),
278 rssi, last_avg_rssi, ra->ra_avg_rssi));
279 }
280
281 /*
282 * Adapt the data rate to suit the conditions. When a transmitted
283 * packet is dropped after IEEE80211_RSSADAPT_RETRY_LIMIT retransmissions,
284 * raise the RSS threshold for transmitting packets of similar length at
285 * the same data rate.
286 */
287 void
288 ieee80211_rssadapt_lower_rate(struct ieee80211com *ic,
289 struct ieee80211_node *ni, struct ieee80211_rssadapt *ra,
290 struct ieee80211_rssdesc *id)
291 {
292 struct ieee80211_rateset *rs = &ni->ni_rates;
293 u_int16_t last_thr;
294 u_int i, thridx, top;
295
296 ra->ra_nfail++;
297
298 if (id->id_rateidx >= rs->rs_nrates) {
299 RSSADAPT_PRINTF(("ieee80211_rssadapt_lower_rate: "
300 "%s rate #%d > #%d out of bounds\n",
301 ether_sprintf(ni->ni_macaddr), id->id_rateidx,
302 rs->rs_nrates - 1));
303 return;
304 }
305
306 for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
307 i < IEEE80211_RSSADAPT_BKTS;
308 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
309 thridx = i;
310 if (id->id_len <= top)
311 break;
312 }
313
314 last_thr = ra->ra_rate_thresh[thridx][id->id_rateidx];
315 ra->ra_rate_thresh[thridx][id->id_rateidx] =
316 interpolate(master_expavgctl.rc_thresh, last_thr,
317 (id->id_rssi << 8));
318
319 RSSADAPT_PRINTF(("%s: dst %s rssi %d threshold[%d, %d.%d] %d -> %d\n",
320 ic->ic_if.if_xname, ether_sprintf(ni->ni_macaddr),
321 id->id_rssi, id->id_len,
322 (rs->rs_rates[id->id_rateidx] & IEEE80211_RATE_VAL) / 2,
323 (rs->rs_rates[id->id_rateidx] & IEEE80211_RATE_VAL) * 5 % 10,
324 last_thr, ra->ra_rate_thresh[thridx][id->id_rateidx]));
325 }
326
327 void
328 ieee80211_rssadapt_raise_rate(struct ieee80211com *ic,
329 struct ieee80211_rssadapt *ra, struct ieee80211_rssdesc *id)
330 {
331 u_int16_t (*thrs)[IEEE80211_RATE_SIZE], newthr, oldthr;
332 struct ieee80211_node *ni = id->id_node;
333 struct ieee80211_rateset *rs = &ni->ni_rates;
334 int i, rate, top;
335 #ifdef IEEE80211_DEBUG
336 int j;
337 #endif
338
339 ra->ra_nok++;
340
341 if (!ratecheck(&ra->ra_last_raise, &ra->ra_raise_interval))
342 return;
343
344 for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
345 i < IEEE80211_RSSADAPT_BKTS;
346 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
347 thrs = &ra->ra_rate_thresh[i];
348 if (id->id_len <= top)
349 break;
350 }
351
352 if (id->id_rateidx + 1 < rs->rs_nrates &&
353 (*thrs)[id->id_rateidx + 1] > (*thrs)[id->id_rateidx]) {
354 rate = (rs->rs_rates[id->id_rateidx + 1] & IEEE80211_RATE_VAL);
355
356 RSSADAPT_PRINTF(("%s: threshold[%d, %d.%d] decay %d ",
357 ic->ic_if.if_xname,
358 IEEE80211_RSSADAPT_BKT0 << (IEEE80211_RSSADAPT_BKTPOWER* i),
359 rate / 2, rate * 5 % 10, (*thrs)[id->id_rateidx + 1]));
360 oldthr = (*thrs)[id->id_rateidx + 1];
361 if ((*thrs)[id->id_rateidx] == 0)
362 newthr = ra->ra_avg_rssi;
363 else
364 newthr = (*thrs)[id->id_rateidx];
365 (*thrs)[id->id_rateidx + 1] =
366 interpolate(master_expavgctl.rc_decay, oldthr, newthr);
367
368 RSSADAPT_PRINTF(("-> %d\n", (*thrs)[id->id_rateidx + 1]));
369 }
370
371 #ifdef IEEE80211_DEBUG
372 if (RSSADAPT_DO_PRINT()) {
373 printf("%s: dst %s thresholds\n", ic->ic_if.if_xname,
374 ether_sprintf(ni->ni_macaddr));
375 for (i = 0; i < IEEE80211_RSSADAPT_BKTS; i++) {
376 printf("%d-byte", IEEE80211_RSSADAPT_BKT0 << (IEEE80211_RSSADAPT_BKTPOWER * i));
377 for (j = 0; j < rs->rs_nrates; j++) {
378 rate = (rs->rs_rates[j] & IEEE80211_RATE_VAL);
379 printf(", T[%d.%d] = %d", rate / 2,
380 rate * 5 % 10, ra->ra_rate_thresh[i][j]);
381 }
382 printf("\n");
383 }
384 }
385 #endif /* IEEE80211_DEBUG */
386 }
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