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 <netproto/802_11/ieee80211_var.h>
49 #include <netproto/802_11/ieee80211_rssadapt.h>
50 #include <netproto/802_11/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
rssadapt_setinterval(const struct ieee80211vap * vap,int msecs)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
rssadapt_init(struct ieee80211vap * vap)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 #if defined(__DragonFly__)
136 vap->iv_rs = rs = kmalloc(sizeof(struct ieee80211_rssadapt),
137 M_80211_RATECTL, M_INTWAIT|M_ZERO);
138 #else
139 vap->iv_rs = rs = IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt),
140 M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
141 #endif
142 if (rs == NULL) {
143 if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
144 return;
145 }
146 rs->vap = vap;
147 rssadapt_setinterval(vap, 500 /* msecs */);
148 rssadapt_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
149 }
150
151 static void
rssadapt_deinit(struct ieee80211vap * vap)152 rssadapt_deinit(struct ieee80211vap *vap)
153 {
154 IEEE80211_FREE(vap->iv_rs, M_80211_RATECTL);
155 }
156
157 static void
rssadapt_updatestats(struct ieee80211_rssadapt_node * ra)158 rssadapt_updatestats(struct ieee80211_rssadapt_node *ra)
159 {
160 long interval;
161
162 ra->ra_pktrate = (ra->ra_pktrate + 10*(ra->ra_nfail + ra->ra_nok))/2;
163 ra->ra_nfail = ra->ra_nok = 0;
164
165 /*
166 * A node is eligible for its rate to be raised every 1/10 to 10
167 * seconds, more eligible in proportion to recent packet rates.
168 */
169 interval = MAX(10*1000, 10*1000 / MAX(1, 10 * ra->ra_pktrate));
170 ra->ra_raise_interval = msecs_to_ticks(interval);
171 }
172
173 static void
rssadapt_node_init(struct ieee80211_node * ni)174 rssadapt_node_init(struct ieee80211_node *ni)
175 {
176 struct ieee80211_rssadapt_node *ra;
177 struct ieee80211vap *vap = ni->ni_vap;
178 struct ieee80211_rssadapt *rsa = vap->iv_rs;
179 const struct ieee80211_rateset *rs = &ni->ni_rates;
180
181 if (ni->ni_rctls == NULL) {
182 ni->ni_rctls = ra =
183 #if defined(__DragonFly__)
184 kmalloc(sizeof(struct ieee80211_rssadapt_node),
185 M_80211_RATECTL, M_INTWAIT|M_ZERO);
186 #else
187 IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt_node),
188 M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
189 #endif
190 if (ra == NULL) {
191 if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
192 "structure\n");
193 return;
194 }
195 } else
196 ra = ni->ni_rctls;
197 ra->ra_rs = rsa;
198 ra->ra_rates = *rs;
199 rssadapt_updatestats(ra);
200
201 /* pick initial rate */
202 for (ra->ra_rix = rs->rs_nrates - 1;
203 ra->ra_rix > 0 && (rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL) > 72;
204 ra->ra_rix--)
205 ;
206 ni->ni_txrate = rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL;
207 ra->ra_ticks = ticks;
208
209 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
210 "RSSADAPT initial rate %d", ni->ni_txrate);
211 }
212
213 static void
rssadapt_node_deinit(struct ieee80211_node * ni)214 rssadapt_node_deinit(struct ieee80211_node *ni)
215 {
216
217 IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
218 }
219
220 static __inline int
bucket(int pktlen)221 bucket(int pktlen)
222 {
223 int i, top, thridx;
224
225 for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
226 i < IEEE80211_RSSADAPT_BKTS;
227 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
228 thridx = i;
229 if (pktlen <= top)
230 break;
231 }
232 return thridx;
233 }
234
235 static int
rssadapt_rate(struct ieee80211_node * ni,void * arg __unused,uint32_t iarg)236 rssadapt_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg)
237 {
238 struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
239 u_int pktlen = iarg;
240 const struct ieee80211_rateset *rs = &ra->ra_rates;
241 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
242 int rix, rssi;
243
244 if ((ticks - ra->ra_ticks) > ra->ra_rs->interval) {
245 rssadapt_updatestats(ra);
246 ra->ra_ticks = ticks;
247 }
248
249 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
250
251 /* XXX this is average rssi, should be using last value */
252 rssi = ni->ni_ic->ic_node_getrssi(ni);
253 for (rix = rs->rs_nrates-1; rix >= 0; rix--)
254 if ((*thrs)[rix] < (rssi << 8))
255 break;
256 if (rix != ra->ra_rix) {
257 /* update public rate */
258 ni->ni_txrate = ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
259 ra->ra_rix = rix;
260
261 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
262 "RSSADAPT new rate %d (pktlen %d rssi %d)",
263 ni->ni_txrate, pktlen, rssi);
264 }
265 return rix;
266 }
267
268 /*
269 * Adapt the data rate to suit the conditions. When a transmitted
270 * packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions,
271 * raise the RSS threshold for transmitting packets of similar length at
272 * the same data rate.
273 */
274 static void
rssadapt_lower_rate(struct ieee80211_rssadapt_node * ra,int pktlen,int rssi)275 rssadapt_lower_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
276 {
277 uint16_t last_thr;
278 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
279 u_int rix;
280
281 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
282
283 rix = ra->ra_rix;
284 last_thr = (*thrs)[rix];
285 (*thrs)[rix] = interpolate(master_expavgctl.rc_thresh,
286 last_thr, (rssi << 8));
287
288 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
289 "RSSADAPT lower threshold for rate %d (last_thr %d new thr %d rssi %d)\n",
290 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
291 last_thr, (*thrs)[rix], rssi);
292 }
293
294 static void
rssadapt_raise_rate(struct ieee80211_rssadapt_node * ra,int pktlen,int rssi)295 rssadapt_raise_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
296 {
297 uint16_t (*thrs)[IEEE80211_RATE_SIZE];
298 uint16_t newthr, oldthr;
299 int rix;
300
301 thrs = &ra->ra_rate_thresh[bucket(pktlen)];
302
303 rix = ra->ra_rix;
304 if ((*thrs)[rix + 1] > (*thrs)[rix]) {
305 oldthr = (*thrs)[rix + 1];
306 if ((*thrs)[rix] == 0)
307 newthr = (rssi << 8);
308 else
309 newthr = (*thrs)[rix];
310 (*thrs)[rix + 1] = interpolate(master_expavgctl.rc_decay,
311 oldthr, newthr);
312
313 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
314 "RSSADAPT raise threshold for rate %d (oldthr %d newthr %d rssi %d)\n",
315 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
316 oldthr, newthr, rssi);
317
318 ra->ra_last_raise = ticks;
319 }
320 }
321
322 static void
rssadapt_tx_complete(const struct ieee80211vap * vap,const struct ieee80211_node * ni,int success,void * arg1,void * arg2)323 rssadapt_tx_complete(const struct ieee80211vap *vap,
324 const struct ieee80211_node *ni, int success, void *arg1, void *arg2)
325 {
326 struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
327 int pktlen = *(int *)arg1, rssi = *(int *)arg2;
328
329 if (success) {
330 ra->ra_nok++;
331 if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates &&
332 (ticks - ra->ra_last_raise) >= ra->ra_raise_interval)
333 rssadapt_raise_rate(ra, pktlen, rssi);
334 } else {
335 ra->ra_nfail++;
336 rssadapt_lower_rate(ra, pktlen, rssi);
337 }
338 }
339
340 static int
rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS)341 rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS)
342 {
343 struct ieee80211vap *vap = arg1;
344 struct ieee80211_rssadapt *rs = vap->iv_rs;
345 int msecs = ticks_to_msecs(rs->interval);
346 int error;
347
348 error = sysctl_handle_int(oidp, &msecs, 0, req);
349 if (error || !req->newptr)
350 return error;
351 rssadapt_setinterval(vap, msecs);
352 return 0;
353 }
354
355 static void
rssadapt_sysctlattach(struct ieee80211vap * vap,struct sysctl_ctx_list * ctx,struct sysctl_oid * tree)356 rssadapt_sysctlattach(struct ieee80211vap *vap,
357 struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
358 {
359
360 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
361 "rssadapt_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
362 0, rssadapt_sysctl_interval, "I", "rssadapt operation interval (ms)");
363 }
364