1 /*- 2 * Copyright (c) 2007-2008 Sam Leffler, Errno Consulting 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * 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 copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #include <sys/cdefs.h> 27 #ifdef __FreeBSD__ 28 __FBSDID("$FreeBSD$"); 29 #endif 30 31 /* 32 * IEEE 802.11 DFS/Radar support. 33 */ 34 #include "opt_inet.h" 35 #include "opt_wlan.h" 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/mbuf.h> 40 #include <sys/malloc.h> 41 #include <sys/kernel.h> 42 43 #include <sys/socket.h> 44 #include <sys/sockio.h> 45 #include <sys/endian.h> 46 #include <sys/errno.h> 47 #include <sys/proc.h> 48 #include <sys/sysctl.h> 49 50 #include <net/if.h> 51 #include <net/if_media.h> 52 53 #include <net80211/ieee80211_var.h> 54 55 static MALLOC_DEFINE(M_80211_DFS, "80211dfs", "802.11 DFS state"); 56 57 static int ieee80211_nol_timeout = 30*60; /* 30 minutes */ 58 SYSCTL_INT(_net_wlan, OID_AUTO, nol_timeout, CTLFLAG_RW, 59 &ieee80211_nol_timeout, 0, "NOL timeout (secs)"); 60 #define NOL_TIMEOUT msecs_to_ticks(ieee80211_nol_timeout*1000) 61 62 static int ieee80211_cac_timeout = 60; /* 60 seconds */ 63 SYSCTL_INT(_net_wlan, OID_AUTO, cac_timeout, CTLFLAG_RW, 64 &ieee80211_cac_timeout, 0, "CAC timeout (secs)"); 65 #define CAC_TIMEOUT msecs_to_ticks(ieee80211_cac_timeout*1000) 66 67 static int 68 null_set_quiet(struct ieee80211_node *ni, u_int8_t *quiet_elm) 69 { 70 return ENOSYS; 71 } 72 73 void 74 ieee80211_dfs_attach(struct ieee80211com *ic) 75 { 76 struct ieee80211_dfs_state *dfs = &ic->ic_dfs; 77 78 callout_init_mtx(&dfs->nol_timer, IEEE80211_LOCK_OBJ(ic), 0); 79 callout_init_mtx(&dfs->cac_timer, IEEE80211_LOCK_OBJ(ic), 0); 80 81 ic->ic_set_quiet = null_set_quiet; 82 } 83 84 void 85 ieee80211_dfs_detach(struct ieee80211com *ic) 86 { 87 /* NB: we assume no locking is needed */ 88 ieee80211_dfs_reset(ic); 89 } 90 91 void 92 ieee80211_dfs_reset(struct ieee80211com *ic) 93 { 94 struct ieee80211_dfs_state *dfs = &ic->ic_dfs; 95 int i; 96 97 /* NB: we assume no locking is needed */ 98 /* NB: cac_timer should be cleared by the state machine */ 99 callout_drain(&dfs->nol_timer); 100 for (i = 0; i < ic->ic_nchans; i++) 101 ic->ic_channels[i].ic_state = 0; 102 dfs->lastchan = NULL; 103 } 104 105 static void 106 cac_timeout(void *arg) 107 { 108 struct ieee80211vap *vap = arg; 109 struct ieee80211com *ic = vap->iv_ic; 110 struct ieee80211_dfs_state *dfs = &ic->ic_dfs; 111 int i; 112 113 IEEE80211_LOCK_ASSERT(ic); 114 115 if (vap->iv_state != IEEE80211_S_CAC) /* NB: just in case */ 116 return; 117 /* 118 * When radar is detected during a CAC we are woken 119 * up prematurely to switch to a new channel. 120 * Check the channel to decide how to act. 121 */ 122 if (IEEE80211_IS_CHAN_RADAR(ic->ic_curchan)) { 123 ieee80211_notify_cac(ic, ic->ic_curchan, 124 IEEE80211_NOTIFY_CAC_RADAR); 125 126 if_printf(vap->iv_ifp, 127 "CAC timer on channel %u (%u MHz) stopped due to radar\n", 128 ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq); 129 130 /* XXX clobbers any existing desired channel */ 131 /* NB: dfs->newchan may be NULL, that's ok */ 132 vap->iv_des_chan = dfs->newchan; 133 /* XXX recursive lock need ieee80211_new_state_locked */ 134 ieee80211_new_state(vap, IEEE80211_S_SCAN, 0); 135 } else { 136 if_printf(vap->iv_ifp, 137 "CAC timer on channel %u (%u MHz) expired; " 138 "no radar detected\n", 139 ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq); 140 /* 141 * Mark all channels with the current frequency 142 * as having completed CAC; this keeps us from 143 * doing it again until we change channels. 144 */ 145 for (i = 0; i < ic->ic_nchans; i++) { 146 struct ieee80211_channel *c = &ic->ic_channels[i]; 147 if (c->ic_freq == ic->ic_curchan->ic_freq) 148 c->ic_state |= IEEE80211_CHANSTATE_CACDONE; 149 } 150 ieee80211_notify_cac(ic, ic->ic_curchan, 151 IEEE80211_NOTIFY_CAC_EXPIRE); 152 ieee80211_cac_completeswitch(vap); 153 } 154 } 155 156 /* 157 * Initiate the CAC timer. The driver is responsible 158 * for setting up the hardware to scan for radar on the 159 * channnel, we just handle timing things out. 160 */ 161 void 162 ieee80211_dfs_cac_start(struct ieee80211vap *vap) 163 { 164 struct ieee80211com *ic = vap->iv_ic; 165 struct ieee80211_dfs_state *dfs = &ic->ic_dfs; 166 167 IEEE80211_LOCK_ASSERT(ic); 168 169 callout_reset(&dfs->cac_timer, CAC_TIMEOUT, cac_timeout, vap); 170 if_printf(vap->iv_ifp, "start %d second CAC timer on channel %u (%u MHz)\n", 171 ticks_to_secs(CAC_TIMEOUT), 172 ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq); 173 ieee80211_notify_cac(ic, ic->ic_curchan, IEEE80211_NOTIFY_CAC_START); 174 } 175 176 /* 177 * Clear the CAC timer. 178 */ 179 void 180 ieee80211_dfs_cac_stop(struct ieee80211vap *vap) 181 { 182 struct ieee80211com *ic = vap->iv_ic; 183 struct ieee80211_dfs_state *dfs = &ic->ic_dfs; 184 185 IEEE80211_LOCK_ASSERT(ic); 186 187 /* NB: racey but not important */ 188 if (callout_pending(&dfs->cac_timer)) { 189 if_printf(vap->iv_ifp, "stop CAC timer on channel %u (%u MHz)\n", 190 ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq); 191 ieee80211_notify_cac(ic, ic->ic_curchan, 192 IEEE80211_NOTIFY_CAC_STOP); 193 } 194 callout_stop(&dfs->cac_timer); 195 } 196 197 void 198 ieee80211_dfs_cac_clear(struct ieee80211com *ic, 199 const struct ieee80211_channel *chan) 200 { 201 int i; 202 203 for (i = 0; i < ic->ic_nchans; i++) { 204 struct ieee80211_channel *c = &ic->ic_channels[i]; 205 if (c->ic_freq == chan->ic_freq) 206 c->ic_state &= ~IEEE80211_CHANSTATE_CACDONE; 207 } 208 } 209 210 static void 211 dfs_timeout(void *arg) 212 { 213 struct ieee80211com *ic = arg; 214 struct ieee80211_dfs_state *dfs = &ic->ic_dfs; 215 struct ieee80211_channel *c; 216 int i, oldest, now; 217 218 IEEE80211_LOCK_ASSERT(ic); 219 220 now = oldest = ticks; 221 for (i = 0; i < ic->ic_nchans; i++) { 222 c = &ic->ic_channels[i]; 223 if (IEEE80211_IS_CHAN_RADAR(c)) { 224 if (time_after_eq(now, dfs->nol_event[i]+NOL_TIMEOUT)) { 225 c->ic_state &= ~IEEE80211_CHANSTATE_RADAR; 226 if (c->ic_state & IEEE80211_CHANSTATE_NORADAR) { 227 /* 228 * NB: do this here so we get only one 229 * msg instead of one for every channel 230 * table entry. 231 */ 232 if_printf(ic->ic_ifp, "radar on channel" 233 " %u (%u MHz) cleared after timeout\n", 234 c->ic_ieee, c->ic_freq); 235 /* notify user space */ 236 c->ic_state &= 237 ~IEEE80211_CHANSTATE_NORADAR; 238 ieee80211_notify_radar(ic, c); 239 } 240 } else if (dfs->nol_event[i] < oldest) 241 oldest = dfs->nol_event[i]; 242 } 243 } 244 if (oldest != now) { 245 /* arrange to process next channel up for a status change */ 246 callout_schedule(&dfs->nol_timer, oldest + NOL_TIMEOUT - now); 247 } 248 } 249 250 static void 251 announce_radar(struct ifnet *ifp, const struct ieee80211_channel *curchan, 252 const struct ieee80211_channel *newchan) 253 { 254 if (newchan == NULL) 255 if_printf(ifp, "radar detected on channel %u (%u MHz)\n", 256 curchan->ic_ieee, curchan->ic_freq); 257 else 258 if_printf(ifp, "radar detected on channel %u (%u MHz), " 259 "moving to channel %u (%u MHz)\n", 260 curchan->ic_ieee, curchan->ic_freq, 261 newchan->ic_ieee, newchan->ic_freq); 262 } 263 264 /* 265 * Handle a radar detection event on a channel. The channel is 266 * added to the NOL list and we record the time of the event. 267 * Entries are aged out after NOL_TIMEOUT. If radar was 268 * detected while doing CAC we force a state/channel change. 269 * Otherwise radar triggers a channel switch using the CSA 270 * mechanism (when the channel is the bss channel). 271 */ 272 void 273 ieee80211_dfs_notify_radar(struct ieee80211com *ic, struct ieee80211_channel *chan) 274 { 275 struct ieee80211_dfs_state *dfs = &ic->ic_dfs; 276 int i, now; 277 278 IEEE80211_LOCK_ASSERT(ic); 279 280 /* 281 * Mark all entries with this frequency. Notify user 282 * space and arrange for notification when the radar 283 * indication is cleared. Then kick the NOL processing 284 * thread if not already running. 285 */ 286 now = ticks; 287 for (i = 0; i < ic->ic_nchans; i++) { 288 struct ieee80211_channel *c = &ic->ic_channels[i]; 289 if (c->ic_freq == chan->ic_freq) { 290 c->ic_state &= ~IEEE80211_CHANSTATE_CACDONE; 291 c->ic_state |= IEEE80211_CHANSTATE_RADAR; 292 dfs->nol_event[i] = now; 293 } 294 } 295 ieee80211_notify_radar(ic, chan); 296 chan->ic_state |= IEEE80211_CHANSTATE_NORADAR; 297 if (!callout_pending(&dfs->nol_timer)) 298 callout_reset(&dfs->nol_timer, NOL_TIMEOUT, dfs_timeout, ic); 299 300 /* 301 * If radar is detected on the bss channel while 302 * doing CAC; force a state change by scheduling the 303 * callout to be dispatched asap. Otherwise, if this 304 * event is for the bss channel then we must quiet 305 * traffic and schedule a channel switch. 306 * 307 * Note this allows us to receive notification about 308 * channels other than the bss channel; not sure 309 * that can/will happen but it's simple to support. 310 */ 311 if (chan == ic->ic_bsschan) { 312 /* XXX need a way to defer to user app */ 313 dfs->newchan = ieee80211_dfs_pickchannel(ic); 314 315 announce_radar(ic->ic_ifp, chan, dfs->newchan); 316 317 if (callout_pending(&dfs->cac_timer)) 318 callout_schedule(&dfs->cac_timer, 0); 319 else if (dfs->newchan != NULL) { 320 /* XXX mode 1, switch count 2 */ 321 /* XXX calculate switch count based on max 322 switch time and beacon interval? */ 323 ieee80211_csa_startswitch(ic, dfs->newchan, 1, 2); 324 } else { 325 /* 326 * Spec says to stop all transmissions and 327 * wait on the current channel for an entry 328 * on the NOL to expire. 329 */ 330 /*XXX*/ 331 if_printf(ic->ic_ifp, "%s: No free channels; waiting for entry " 332 "on NOL to expire\n", __func__); 333 } 334 } else { 335 /* 336 * Issue rate-limited console msgs. 337 */ 338 if (dfs->lastchan != chan) { 339 dfs->lastchan = chan; 340 dfs->cureps = 0; 341 announce_radar(ic->ic_ifp, chan, NULL); 342 } else if (ppsratecheck(&dfs->lastevent, &dfs->cureps, 1)) { 343 announce_radar(ic->ic_ifp, chan, NULL); 344 } 345 } 346 } 347 348 struct ieee80211_channel * 349 ieee80211_dfs_pickchannel(struct ieee80211com *ic) 350 { 351 struct ieee80211_channel *c; 352 int i, flags; 353 uint16_t v; 354 355 /* 356 * Consult the scan cache first. 357 */ 358 flags = ic->ic_curchan->ic_flags & IEEE80211_CHAN_ALL; 359 /* 360 * XXX if curchan is HT this will never find a channel 361 * XXX 'cuz we scan only legacy channels 362 */ 363 c = ieee80211_scan_pickchannel(ic, flags); 364 if (c != NULL) 365 return c; 366 /* 367 * No channel found in scan cache; select a compatible 368 * one at random (skipping channels where radar has 369 * been detected). 370 */ 371 get_random_bytes(&v, sizeof(v)); 372 v %= ic->ic_nchans; 373 for (i = v; i < ic->ic_nchans; i++) { 374 c = &ic->ic_channels[i]; 375 if (!IEEE80211_IS_CHAN_RADAR(c) && 376 (c->ic_flags & flags) == flags) 377 return c; 378 } 379 for (i = 0; i < v; i++) { 380 c = &ic->ic_channels[i]; 381 if (!IEEE80211_IS_CHAN_RADAR(c) && 382 (c->ic_flags & flags) == flags) 383 return c; 384 } 385 if_printf(ic->ic_ifp, "HELP, no channel located to switch to!\n"); 386 return NULL; 387 } 388