1/*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2007-2008 Sam Leffler, Errno Consulting 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * 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 copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28/* 29 * IEEE 802.11 DFS/Radar support. 30 */ 31#include "opt_inet.h" 32#include "opt_wlan.h" 33 34#include <sys/param.h> 35#include <sys/systm.h> 36#include <sys/mbuf.h> 37#include <sys/malloc.h> 38#include <sys/kernel.h> 39 40#include <sys/socket.h> 41#include <sys/sockio.h> 42#include <sys/endian.h> 43#include <sys/errno.h> 44#include <sys/proc.h> 45#include <sys/sysctl.h> 46 47#include <net/if.h> 48#include <net/if_var.h> 49#include <net/if_media.h> 50#include <net/ethernet.h> 51 52#include <net80211/ieee80211_var.h> 53 54static MALLOC_DEFINE(M_80211_DFS, "80211dfs", "802.11 DFS state"); 55 56static int ieee80211_nol_timeout = 30*60; /* 30 minutes */ 57SYSCTL_INT(_net_wlan, OID_AUTO, nol_timeout, CTLFLAG_RW, 58 &ieee80211_nol_timeout, 0, "NOL timeout (secs)"); 59#define NOL_TIMEOUT msecs_to_ticks(ieee80211_nol_timeout*1000) 60 61static int ieee80211_cac_timeout = 60; /* 60 seconds */ 62SYSCTL_INT(_net_wlan, OID_AUTO, cac_timeout, CTLFLAG_RW, 63 &ieee80211_cac_timeout, 0, "CAC timeout (secs)"); 64#define CAC_TIMEOUT msecs_to_ticks(ieee80211_cac_timeout*1000) 65 66/* 67 DFS* In order to facilitate debugging, a couple of operating 68 * modes aside from the default are needed. 69 * 70 * 0 - default CAC/NOL behaviour - ie, start CAC, place 71 * channel on NOL list. 72 * 1 - send CAC, but don't change channel or add the channel 73 * to the NOL list. 74 * 2 - just match on radar, don't send CAC or place channel in 75 * the NOL list. 76 */ 77static int ieee80211_dfs_debug = DFS_DBG_NONE; 78 79/* 80 * This option must not be included in the default kernel 81 * as it allows users to plainly disable CAC/NOL handling. 82 */ 83#ifdef IEEE80211_DFS_DEBUG 84SYSCTL_INT(_net_wlan, OID_AUTO, dfs_debug, CTLFLAG_RW, 85 &ieee80211_dfs_debug, 0, "DFS debug behaviour"); 86#endif 87 88static int 89null_set_quiet(struct ieee80211_node *ni, u_int8_t *quiet_elm) 90{ 91 return ENOSYS; 92} 93 94void 95ieee80211_dfs_attach(struct ieee80211com *ic) 96{ 97 struct ieee80211_dfs_state *dfs = &ic->ic_dfs; 98 99 callout_init_mtx(&dfs->nol_timer, IEEE80211_LOCK_OBJ(ic), 0); 100 callout_init_mtx(&dfs->cac_timer, IEEE80211_LOCK_OBJ(ic), 0); 101 102 ic->ic_set_quiet = null_set_quiet; 103} 104 105void 106ieee80211_dfs_detach(struct ieee80211com *ic) 107{ 108 /* NB: we assume no locking is needed */ 109 ieee80211_dfs_reset(ic); 110} 111 112void 113ieee80211_dfs_reset(struct ieee80211com *ic) 114{ 115 struct ieee80211_dfs_state *dfs = &ic->ic_dfs; 116 int i; 117 118 /* NB: we assume no locking is needed */ 119 /* NB: cac_timer should be cleared by the state machine */ 120 callout_drain(&dfs->nol_timer); 121 for (i = 0; i < ic->ic_nchans; i++) 122 ic->ic_channels[i].ic_state = 0; 123 dfs->lastchan = NULL; 124} 125 126static void 127cac_timeout(void *arg) 128{ 129 struct ieee80211vap *vap = arg; 130 struct ieee80211com *ic = vap->iv_ic; 131 struct ieee80211_dfs_state *dfs = &ic->ic_dfs; 132 int i; 133 134 IEEE80211_LOCK_ASSERT(ic); 135 136 if (vap->iv_state != IEEE80211_S_CAC) /* NB: just in case */ 137 return; 138 /* 139 * When radar is detected during a CAC we are woken 140 * up prematurely to switch to a new channel. 141 * Check the channel to decide how to act. 142 */ 143 if (IEEE80211_IS_CHAN_RADAR(ic->ic_curchan)) { 144 ieee80211_notify_cac(ic, ic->ic_curchan, 145 IEEE80211_NOTIFY_CAC_RADAR); 146 147 if_printf(vap->iv_ifp, 148 "CAC timer on channel %u (%u MHz) stopped due to radar\n", 149 ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq); 150 151 /* XXX clobbers any existing desired channel */ 152 /* NB: dfs->newchan may be NULL, that's ok */ 153 vap->iv_des_chan = dfs->newchan; 154 ieee80211_new_state_locked(vap, IEEE80211_S_SCAN, 0); 155 } else { 156 if_printf(vap->iv_ifp, 157 "CAC timer on channel %u (%u MHz) expired; " 158 "no radar detected\n", 159 ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq); 160 /* 161 * Mark all channels with the current frequency 162 * as having completed CAC; this keeps us from 163 * doing it again until we change channels. 164 */ 165 for (i = 0; i < ic->ic_nchans; i++) { 166 struct ieee80211_channel *c = &ic->ic_channels[i]; 167 if (c->ic_freq == ic->ic_curchan->ic_freq) 168 c->ic_state |= IEEE80211_CHANSTATE_CACDONE; 169 } 170 ieee80211_notify_cac(ic, ic->ic_curchan, 171 IEEE80211_NOTIFY_CAC_EXPIRE); 172 ieee80211_cac_completeswitch(vap); 173 } 174} 175 176/* 177 * Initiate the CAC timer. The driver is responsible 178 * for setting up the hardware to scan for radar on the 179 * channnel, we just handle timing things out. 180 */ 181void 182ieee80211_dfs_cac_start(struct ieee80211vap *vap) 183{ 184 struct ieee80211com *ic = vap->iv_ic; 185 struct ieee80211_dfs_state *dfs = &ic->ic_dfs; 186 187 IEEE80211_LOCK_ASSERT(ic); 188 189 callout_reset(&dfs->cac_timer, CAC_TIMEOUT, cac_timeout, vap); 190 if_printf(vap->iv_ifp, "start %d second CAC timer on channel %u (%u MHz)\n", 191 ticks_to_secs(CAC_TIMEOUT), 192 ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq); 193 ieee80211_notify_cac(ic, ic->ic_curchan, IEEE80211_NOTIFY_CAC_START); 194} 195 196/* 197 * Clear the CAC timer. 198 */ 199void 200ieee80211_dfs_cac_stop(struct ieee80211vap *vap) 201{ 202 struct ieee80211com *ic = vap->iv_ic; 203 struct ieee80211_dfs_state *dfs = &ic->ic_dfs; 204 205 IEEE80211_LOCK_ASSERT(ic); 206 207 /* NB: racey but not important */ 208 if (callout_pending(&dfs->cac_timer)) { 209 if_printf(vap->iv_ifp, "stop CAC timer on channel %u (%u MHz)\n", 210 ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq); 211 ieee80211_notify_cac(ic, ic->ic_curchan, 212 IEEE80211_NOTIFY_CAC_STOP); 213 } 214 callout_stop(&dfs->cac_timer); 215} 216 217void 218ieee80211_dfs_cac_clear(struct ieee80211com *ic, 219 const struct ieee80211_channel *chan) 220{ 221 int i; 222 223 for (i = 0; i < ic->ic_nchans; i++) { 224 struct ieee80211_channel *c = &ic->ic_channels[i]; 225 if (c->ic_freq == chan->ic_freq) 226 c->ic_state &= ~IEEE80211_CHANSTATE_CACDONE; 227 } 228} 229 230static void 231dfs_timeout(void *arg) 232{ 233 struct ieee80211com *ic = arg; 234 struct ieee80211_dfs_state *dfs = &ic->ic_dfs; 235 struct ieee80211_channel *c; 236 int i, oldest, now; 237 238 IEEE80211_LOCK_ASSERT(ic); 239 240 now = oldest = ticks; 241 for (i = 0; i < ic->ic_nchans; i++) { 242 c = &ic->ic_channels[i]; 243 if (IEEE80211_IS_CHAN_RADAR(c)) { 244 if (ieee80211_time_after_eq(now, dfs->nol_event[i]+NOL_TIMEOUT)) { 245 c->ic_state &= ~IEEE80211_CHANSTATE_RADAR; 246 if (c->ic_state & IEEE80211_CHANSTATE_NORADAR) { 247 /* 248 * NB: do this here so we get only one 249 * msg instead of one for every channel 250 * table entry. 251 */ 252 ic_printf(ic, "radar on channel %u " 253 "(%u MHz) cleared after timeout\n", 254 c->ic_ieee, c->ic_freq); 255 /* notify user space */ 256 c->ic_state &= 257 ~IEEE80211_CHANSTATE_NORADAR; 258 ieee80211_notify_radar(ic, c); 259 } 260 } else if (dfs->nol_event[i] < oldest) 261 oldest = dfs->nol_event[i]; 262 } 263 } 264 if (oldest != now) { 265 /* arrange to process next channel up for a status change */ 266 callout_schedule(&dfs->nol_timer, oldest + NOL_TIMEOUT - now); 267 } 268} 269 270static void 271announce_radar(struct ieee80211com *ic, const struct ieee80211_channel *curchan, 272 const struct ieee80211_channel *newchan) 273{ 274 if (newchan == NULL) 275 ic_printf(ic, "radar detected on channel %u (%u MHz)\n", 276 curchan->ic_ieee, curchan->ic_freq); 277 else 278 ic_printf(ic, "radar detected on channel %u (%u MHz), " 279 "moving to channel %u (%u MHz)\n", 280 curchan->ic_ieee, curchan->ic_freq, 281 newchan->ic_ieee, newchan->ic_freq); 282} 283 284/* 285 * Handle a radar detection event on a channel. The channel is 286 * added to the NOL list and we record the time of the event. 287 * Entries are aged out after NOL_TIMEOUT. If radar was 288 * detected while doing CAC we force a state/channel change. 289 * Otherwise radar triggers a channel switch using the CSA 290 * mechanism (when the channel is the bss channel). 291 */ 292void 293ieee80211_dfs_notify_radar(struct ieee80211com *ic, struct ieee80211_channel *chan) 294{ 295 struct ieee80211_dfs_state *dfs = &ic->ic_dfs; 296 int i, now; 297 298 IEEE80211_LOCK_ASSERT(ic); 299 300 /* 301 * If doing DFS debugging (mode 2), don't bother 302 * running the rest of this function. 303 * 304 * Simply announce the presence of the radar and continue 305 * along merrily. 306 */ 307 if (ieee80211_dfs_debug == DFS_DBG_NOCSANOL) { 308 announce_radar(ic, chan, chan); 309 ieee80211_notify_radar(ic, chan); 310 return; 311 } 312 313 /* 314 * Don't mark the channel and don't put it into NOL 315 * if we're doing DFS debugging. 316 */ 317 if (ieee80211_dfs_debug == DFS_DBG_NONE) { 318 /* 319 * Mark all entries with this frequency. Notify user 320 * space and arrange for notification when the radar 321 * indication is cleared. Then kick the NOL processing 322 * thread if not already running. 323 */ 324 now = ticks; 325 for (i = 0; i < ic->ic_nchans; i++) { 326 struct ieee80211_channel *c = &ic->ic_channels[i]; 327 if (c->ic_freq == chan->ic_freq) { 328 c->ic_state &= ~IEEE80211_CHANSTATE_CACDONE; 329 c->ic_state |= IEEE80211_CHANSTATE_RADAR; 330 dfs->nol_event[i] = now; 331 } 332 } 333 ieee80211_notify_radar(ic, chan); 334 chan->ic_state |= IEEE80211_CHANSTATE_NORADAR; 335 if (!callout_pending(&dfs->nol_timer)) 336 callout_reset(&dfs->nol_timer, NOL_TIMEOUT, 337 dfs_timeout, ic); 338 } 339 340 /* 341 * If radar is detected on the bss channel while 342 * doing CAC; force a state change by scheduling the 343 * callout to be dispatched asap. Otherwise, if this 344 * event is for the bss channel then we must quiet 345 * traffic and schedule a channel switch. 346 * 347 * Note this allows us to receive notification about 348 * channels other than the bss channel; not sure 349 * that can/will happen but it's simple to support. 350 */ 351 if (chan == ic->ic_bsschan) { 352 /* XXX need a way to defer to user app */ 353 354 /* 355 * Don't flip over to a new channel if 356 * we are currently doing DFS debugging. 357 */ 358 if (ieee80211_dfs_debug == DFS_DBG_NONE) 359 dfs->newchan = ieee80211_dfs_pickchannel(ic); 360 else 361 dfs->newchan = chan; 362 363 announce_radar(ic, chan, dfs->newchan); 364 365 if (callout_pending(&dfs->cac_timer)) 366 callout_schedule(&dfs->cac_timer, 0); 367 else if (dfs->newchan != NULL) { 368 /* XXX mode 1, switch count 2 */ 369 /* XXX calculate switch count based on max 370 switch time and beacon interval? */ 371 ieee80211_csa_startswitch(ic, dfs->newchan, 1, 2); 372 } else { 373 /* 374 * Spec says to stop all transmissions and 375 * wait on the current channel for an entry 376 * on the NOL to expire. 377 */ 378 /*XXX*/ 379 ic_printf(ic, "%s: No free channels; waiting for entry " 380 "on NOL to expire\n", __func__); 381 } 382 } else { 383 /* 384 * Issue rate-limited console msgs. 385 */ 386 if (dfs->lastchan != chan) { 387 dfs->lastchan = chan; 388 dfs->cureps = 0; 389 announce_radar(ic, chan, NULL); 390 } else if (ppsratecheck(&dfs->lastevent, &dfs->cureps, 1)) { 391 announce_radar(ic, chan, NULL); 392 } 393 } 394} 395 396struct ieee80211_channel * 397ieee80211_dfs_pickchannel(struct ieee80211com *ic) 398{ 399 struct ieee80211_channel *c; 400 int i, flags; 401 uint16_t v; 402 403 /* 404 * Consult the scan cache first. 405 */ 406 flags = ic->ic_curchan->ic_flags & IEEE80211_CHAN_ALL; 407 /* 408 * XXX if curchan is HT this will never find a channel 409 * XXX 'cuz we scan only legacy channels 410 */ 411 c = ieee80211_scan_pickchannel(ic, flags); 412 if (c != NULL) 413 return c; 414 /* 415 * No channel found in scan cache; select a compatible 416 * one at random (skipping channels where radar has 417 * been detected). 418 */ 419 net80211_get_random_bytes(&v, sizeof(v)); 420 v %= ic->ic_nchans; 421 for (i = v; i < ic->ic_nchans; i++) { 422 c = &ic->ic_channels[i]; 423 if (!IEEE80211_IS_CHAN_RADAR(c) && 424 (c->ic_flags & flags) == flags) 425 return c; 426 } 427 for (i = 0; i < v; i++) { 428 c = &ic->ic_channels[i]; 429 if (!IEEE80211_IS_CHAN_RADAR(c) && 430 (c->ic_flags & flags) == flags) 431 return c; 432 } 433 ic_printf(ic, "HELP, no channel located to switch to!\n"); 434 return NULL; 435} 436