/*- * Copyright (c) 2002-2008 Sam Leffler, Errno Consulting * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include __FBSDID("$FreeBSD: head/sys/net80211/ieee80211_scan.c 178354 2008-04-20 20:35:46Z sam $"); /* * IEEE 802.11 scanning support. */ #include "opt_wlan.h" #include #include #include #include #include #include #include #include #include struct scan_state { struct ieee80211_scan_state base; /* public state */ u_int ss_iflags; /* flags used internally */ #define ISCAN_MINDWELL 0x0001 /* min dwell time reached */ #define ISCAN_DISCARD 0x0002 /* discard rx'd frames */ #define ISCAN_CANCEL 0x0004 /* cancel current scan */ #define ISCAN_START 0x0008 /* 1st time through next_scan */ unsigned long ss_chanmindwell; /* min dwell on curchan */ unsigned long ss_scanend; /* time scan must stop */ u_int ss_duration; /* duration for next scan */ struct callout ss_scan_timer; /* scan timer */ }; #define SCAN_PRIVATE(ss) ((struct scan_state *) ss) /* * Amount of time to go off-channel during a background * scan. This value should be large enough to catch most * ap's but short enough that we can return on-channel * before our listen interval expires. * * XXX tunable * XXX check against configured listen interval */ #define IEEE80211_SCAN_OFFCHANNEL msecs_to_ticks(150) /* * Roaming-related defaults. RSSI thresholds are as returned by the * driver (dBm). Transmit rate thresholds are IEEE rate codes (i.e * .5M units) or MCS. */ #define ROAM_RSSI_11A_DEFAULT 14 /* rssi threshold for 11a bss */ #define ROAM_RSSI_11B_DEFAULT 14 /* rssi threshold for 11b bss */ #define ROAM_RSSI_11BONLY_DEFAULT 14 /* rssi threshold for 11b-only bss */ #define ROAM_RATE_11A_DEFAULT 2*12 /* tx rate thresh for 11a bss */ #define ROAM_RATE_11B_DEFAULT 2*5 /* tx rate thresh for 11b bss */ #define ROAM_RATE_11BONLY_DEFAULT 2*1 /* tx rate thresh for 11b-only bss */ #define ROAM_MCS_11N_DEFAULT 1 /* tx MCS thresh for 11n bss*/ static void scan_restart_pwrsav(void *); static void scan_curchan(struct ieee80211_scan_state *, unsigned long); static void scan_mindwell(struct ieee80211_scan_state *); static void scan_next(void *); MALLOC_DEFINE(M_80211_SCAN, "80211scan", "802.11 scan state"); void ieee80211_scan_attach(struct ieee80211com *ic) { struct scan_state *ss; MALLOC(ss, struct scan_state *, sizeof(struct scan_state), M_80211_SCAN, M_NOWAIT | M_ZERO); if (ss == NULL) { ic->ic_scan = NULL; return; } callout_init_mtx(&ss->ss_scan_timer, &ic->ic_comlock, 0); ic->ic_scan = &ss->base; ic->ic_scan_curchan = scan_curchan; ic->ic_scan_mindwell = scan_mindwell; } void ieee80211_scan_detach(struct ieee80211com *ic) { struct ieee80211_scan_state *ss = ic->ic_scan; if (ss != NULL) { callout_drain(&SCAN_PRIVATE(ss)->ss_scan_timer); if (ss->ss_ops != NULL) { ss->ss_ops->scan_detach(ss); ss->ss_ops = NULL; } ic->ic_flags &= ~IEEE80211_F_SCAN; ic->ic_scan = NULL; FREE(SCAN_PRIVATE(ss), M_80211_SCAN); } } static __inline void setparams(struct ieee80211_roamparam *rp, int8_t rssi, uint8_t txrate) { rp->rssi = rssi; rp->rate = txrate; } void ieee80211_scan_vattach(struct ieee80211vap *vap) { struct ieee80211com *ic = vap->iv_ic; vap->iv_bgscanidle = (IEEE80211_BGSCAN_IDLE_DEFAULT*1000)/hz; vap->iv_bgscanintvl = IEEE80211_BGSCAN_INTVAL_DEFAULT*hz; vap->iv_scanvalid = IEEE80211_SCAN_VALID_DEFAULT*hz; vap->iv_roaming = IEEE80211_ROAMING_AUTO; /* NB: only set supported modes so user apps can identify */ if (isset(ic->ic_modecaps, IEEE80211_MODE_11A)) setparams(&vap->iv_roamparms[IEEE80211_MODE_11A], ROAM_RSSI_11A_DEFAULT, ROAM_RATE_11A_DEFAULT); if (isset(ic->ic_modecaps, IEEE80211_MODE_11G)) setparams(&vap->iv_roamparms[IEEE80211_MODE_11G], ROAM_RSSI_11B_DEFAULT, ROAM_RATE_11B_DEFAULT); if (isset(ic->ic_modecaps, IEEE80211_MODE_11B)) setparams(&vap->iv_roamparms[IEEE80211_MODE_11B], ROAM_RSSI_11BONLY_DEFAULT, ROAM_RATE_11BONLY_DEFAULT); /* NB: default turbo controls to be the same as !turbo */ if (isset(ic->ic_modecaps, IEEE80211_MODE_TURBO_A)) vap->iv_roamparms[IEEE80211_MODE_TURBO_A] = vap->iv_roamparms[IEEE80211_MODE_11A]; if (isset(ic->ic_modecaps, IEEE80211_MODE_TURBO_G)) vap->iv_roamparms[IEEE80211_MODE_TURBO_G] = vap->iv_roamparms[IEEE80211_MODE_11G]; if (isset(ic->ic_modecaps, IEEE80211_MODE_STURBO_A)) vap->iv_roamparms[IEEE80211_MODE_STURBO_A] = vap->iv_roamparms[IEEE80211_MODE_11A]; if (isset(ic->ic_modecaps, IEEE80211_MODE_11NA)) setparams(&vap->iv_roamparms[IEEE80211_MODE_11NA], ROAM_RSSI_11A_DEFAULT, ROAM_MCS_11N_DEFAULT | 0x80); if (isset(ic->ic_modecaps, IEEE80211_MODE_11NG)) setparams(&vap->iv_roamparms[IEEE80211_MODE_11NG], ROAM_RSSI_11B_DEFAULT, ROAM_MCS_11N_DEFAULT | 0x80); } void ieee80211_scan_vdetach(struct ieee80211vap *vap) { struct ieee80211com *ic = vap->iv_ic; struct ieee80211_scan_state *ss; IEEE80211_LOCK(ic); ss = ic->ic_scan; if (ss != NULL && ss->ss_vap == vap) { if (ic->ic_flags & IEEE80211_F_SCAN) { /* XXX callout_drain */ callout_stop(&SCAN_PRIVATE(ss)->ss_scan_timer); ic->ic_flags &= ~IEEE80211_F_SCAN; } if (ss->ss_ops != NULL) { ss->ss_ops->scan_detach(ss); ss->ss_ops = NULL; } ss->ss_vap = NULL; } IEEE80211_UNLOCK(ic); } /* * Simple-minded scanner module support. */ static const char *scan_modnames[IEEE80211_OPMODE_MAX] = { "wlan_scan_sta", /* IEEE80211_M_IBSS */ "wlan_scan_sta", /* IEEE80211_M_STA */ "wlan_scan_wds", /* IEEE80211_M_WDS */ "wlan_scan_sta", /* IEEE80211_M_AHDEMO */ "wlan_scan_ap", /* IEEE80211_M_HOSTAP */ "wlan_scan_monitor", /* IEEE80211_M_MONITOR */ }; static const struct ieee80211_scanner *scanners[IEEE80211_OPMODE_MAX]; const struct ieee80211_scanner * ieee80211_scanner_get(enum ieee80211_opmode mode) { if (mode >= IEEE80211_OPMODE_MAX) return NULL; if (scanners[mode] == NULL) ieee80211_load_module(scan_modnames[mode]); return scanners[mode]; } void ieee80211_scanner_register(enum ieee80211_opmode mode, const struct ieee80211_scanner *scan) { if (mode >= IEEE80211_OPMODE_MAX) return; scanners[mode] = scan; } void ieee80211_scanner_unregister(enum ieee80211_opmode mode, const struct ieee80211_scanner *scan) { if (mode >= IEEE80211_OPMODE_MAX) return; if (scanners[mode] == scan) scanners[mode] = NULL; } void ieee80211_scanner_unregister_all(const struct ieee80211_scanner *scan) { int m; for (m = 0; m < IEEE80211_OPMODE_MAX; m++) if (scanners[m] == scan) scanners[m] = NULL; } /* * Update common scanner state to reflect the current * operating mode. This is called when the state machine * is transitioned to RUN state w/o scanning--e.g. when * operating in monitor mode. The purpose of this is to * ensure later callbacks find ss_ops set to properly * reflect current operating mode. */ static void scan_update_locked(struct ieee80211vap *vap, const struct ieee80211_scanner *scan) { struct ieee80211com *ic = vap->iv_ic; struct ieee80211_scan_state *ss = ic->ic_scan; IEEE80211_LOCK_ASSERT(ic); #ifdef IEEE80211_DEBUG if (ss->ss_vap != vap || ss->ss_ops != scan) { IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: current scanner is <%s:%s>, switch to <%s:%s>\n", __func__, ss->ss_vap != NULL ? ss->ss_vap->iv_ifp->if_xname : "none", ss->ss_vap != NULL ? ieee80211_opmode_name[ss->ss_vap->iv_opmode] : "none", vap->iv_ifp->if_xname, ieee80211_opmode_name[vap->iv_opmode]); } #endif ss->ss_vap = vap; if (ss->ss_ops != scan) { /* * Switch scanners; detach old, attach new. Special * case where a single scan module implements multiple * policies by using different scan ops but a common * core. We assume if the old and new attach methods * are identical then it's ok to just change ss_ops * and not flush the internal state of the module. */ if (scan == NULL || ss->ss_ops == NULL || ss->ss_ops->scan_attach != scan->scan_attach) { if (ss->ss_ops != NULL) ss->ss_ops->scan_detach(ss); if (scan != NULL && !scan->scan_attach(ss)) { /* XXX attach failure */ /* XXX stat+msg */ scan = NULL; } } ss->ss_ops = scan; } } static void change_channel(struct ieee80211com *ic, struct ieee80211_channel *chan) { ic->ic_curchan = chan; ic->ic_set_channel(ic); } static char channel_type(const struct ieee80211_channel *c) { if (IEEE80211_IS_CHAN_ST(c)) return 'S'; if (IEEE80211_IS_CHAN_108A(c)) return 'T'; if (IEEE80211_IS_CHAN_108G(c)) return 'G'; if (IEEE80211_IS_CHAN_HT(c)) return 'n'; if (IEEE80211_IS_CHAN_A(c)) return 'a'; if (IEEE80211_IS_CHAN_ANYG(c)) return 'g'; if (IEEE80211_IS_CHAN_B(c)) return 'b'; return 'f'; } void ieee80211_scan_dump_channels(const struct ieee80211_scan_state *ss) { struct ieee80211com *ic = ss->ss_vap->iv_ic; const char *sep; int i; sep = ""; for (i = ss->ss_next; i < ss->ss_last; i++) { const struct ieee80211_channel *c = ss->ss_chans[i]; printf("%s%u%c", sep, ieee80211_chan2ieee(ic, c), channel_type(c)); sep = ", "; } } #ifdef IEEE80211_DEBUG static void scan_dump(struct ieee80211_scan_state *ss) { struct ieee80211vap *vap = ss->ss_vap; if_printf(vap->iv_ifp, "scan set "); ieee80211_scan_dump_channels(ss); printf(" dwell min %lu max %lu\n", ss->ss_mindwell, ss->ss_maxdwell); } #endif /* IEEE80211_DEBUG */ /* * Enable station power save mode and start/restart the scanning thread. */ static void scan_restart_pwrsav(void *arg) { struct scan_state *ss = (struct scan_state *) arg; struct ieee80211vap *vap = ss->base.ss_vap; struct ieee80211com *ic = vap->iv_ic; int ticksdelay; ieee80211_sta_pwrsave(vap, 1); /* * Use an initial 1ms delay so the null * data frame has a chance to go out. * XXX 1ms is a lot, better to trigger scan * on tx complete. */ ticksdelay = msecs_to_ticks(1); if (ticksdelay < 1) ticksdelay = 1; ic->ic_scan_start(ic); /* notify driver */ ss->ss_scanend = ticks + ticksdelay + ss->ss_duration; ss->ss_iflags |= ISCAN_START; callout_reset(&ss->ss_scan_timer, ticksdelay, scan_next, ss); } /* * Start/restart scanning. If we're operating in station mode * and associated notify the ap we're going into power save mode * and schedule a callback to initiate the work (where there's a * better context for doing the work). Otherwise, start the scan * directly. */ static int scan_restart(struct scan_state *ss, u_int duration) { struct ieee80211vap *vap = ss->base.ss_vap; struct ieee80211com *ic = vap->iv_ic; int defer = 0; if (ss->base.ss_next == ss->base.ss_last) { IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: no channels to scan\n", __func__); return 0; } if (vap->iv_opmode == IEEE80211_M_STA && vap->iv_state == IEEE80211_S_RUN) { if ((vap->iv_bss->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) { /* * Initiate power save before going off-channel. * Note that we cannot do this directly because * of locking issues; instead we defer it to a * tasklet. */ ss->ss_duration = duration; defer = 1; } } if (!defer) { ic->ic_scan_start(ic); /* notify driver */ ss->ss_scanend = ticks + duration; ss->ss_iflags |= ISCAN_START; callout_reset(&ss->ss_scan_timer, 0, scan_next, ss); } else scan_restart_pwrsav(ss); return 1; } static void copy_ssid(struct ieee80211vap *vap, struct ieee80211_scan_state *ss, int nssid, const struct ieee80211_scan_ssid ssids[]) { if (nssid > IEEE80211_SCAN_MAX_SSID) { /* XXX printf */ IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: too many ssid %d, ignoring all of them\n", __func__, nssid); return; } memcpy(ss->ss_ssid, ssids, nssid * sizeof(ssids[0])); ss->ss_nssid = nssid; } /* * Start a scan unless one is already going. */ static int start_scan_locked(const struct ieee80211_scanner *scan, struct ieee80211vap *vap, int flags, u_int duration, u_int mindwell, u_int maxdwell, u_int nssid, const struct ieee80211_scan_ssid ssids[]) { struct ieee80211com *ic = vap->iv_ic; struct ieee80211_scan_state *ss = ic->ic_scan; IEEE80211_LOCK_ASSERT(ic); if (ic->ic_flags & IEEE80211_F_CSAPENDING) { IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: scan inhibited by pending channel change\n", __func__); } else if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) { IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: %s scan, duration %u mindwell %u maxdwell %u, desired mode %s, %s%s%s%s%s%s\n" , __func__ , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive" , duration, mindwell, maxdwell , ieee80211_phymode_name[vap->iv_des_mode] , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append" , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : "" , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : "" , flags & IEEE80211_SCAN_NOBCAST ? ", nobcast" : "" , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : "" , flags & IEEE80211_SCAN_ONCE ? ", once" : "" ); scan_update_locked(vap, scan); if (ss->ss_ops != NULL) { if ((flags & IEEE80211_SCAN_NOSSID) == 0) copy_ssid(vap, ss, nssid, ssids); /* NB: top 4 bits for internal use */ ss->ss_flags = flags & 0xfff; if (ss->ss_flags & IEEE80211_SCAN_ACTIVE) vap->iv_stats.is_scan_active++; else vap->iv_stats.is_scan_passive++; if (flags & IEEE80211_SCAN_FLUSH) ss->ss_ops->scan_flush(ss); /* NB: flush frames rx'd before 1st channel change */ SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD; ss->ss_next = 0; ss->ss_mindwell = mindwell; ss->ss_maxdwell = maxdwell; ss->ss_ops->scan_start(ss, vap); #ifdef IEEE80211_DEBUG if (ieee80211_msg_scan(vap)) scan_dump(ss); #endif /* IEEE80211_DEBUG */ if (scan_restart(SCAN_PRIVATE(ss), duration)) ic->ic_flags |= IEEE80211_F_SCAN; } } else { IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: %s scan already in progress\n", __func__, ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"); } return (ic->ic_flags & IEEE80211_F_SCAN); } /* * Start a scan unless one is already going. */ int ieee80211_start_scan(struct ieee80211vap *vap, int flags, u_int duration, u_int mindwell, u_int maxdwell, u_int nssid, const struct ieee80211_scan_ssid ssids[]) { struct ieee80211com *ic = vap->iv_ic; const struct ieee80211_scanner *scan; int result; scan = ieee80211_scanner_get(vap->iv_opmode); if (scan == NULL) { IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: no scanner support for %s mode\n", __func__, ieee80211_opmode_name[vap->iv_opmode]); /* XXX stat */ return 0; } IEEE80211_LOCK(ic); result = start_scan_locked(scan, vap, flags, duration, mindwell, maxdwell, nssid, ssids); IEEE80211_UNLOCK(ic); return result; } /* * Check the scan cache for an ap/channel to use; if that * fails then kick off a new scan. */ int ieee80211_check_scan(struct ieee80211vap *vap, int flags, u_int duration, u_int mindwell, u_int maxdwell, u_int nssid, const struct ieee80211_scan_ssid ssids[]) { struct ieee80211com *ic = vap->iv_ic; struct ieee80211_scan_state *ss = ic->ic_scan; const struct ieee80211_scanner *scan; int checkscanlist = 0, result; scan = ieee80211_scanner_get(vap->iv_opmode); if (scan == NULL) { IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: no scanner support for %s mode\n", __func__, vap->iv_opmode); /* XXX stat */ return 0; } /* * Check if there's a list of scan candidates already. * XXX want more than the ap we're currently associated with */ IEEE80211_LOCK(ic); IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: %s scan, %s%s%s%s%s\n" , __func__ , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive" , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append" , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : "" , flags & IEEE80211_SCAN_NOJOIN ? ", nojoin" : "" , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : "" , flags & IEEE80211_SCAN_ONCE ? ", once" : "" ); if (ss->ss_ops != scan) { /* XXX re-use cache contents? e.g. adhoc<->sta */ flags |= IEEE80211_SCAN_FLUSH; } scan_update_locked(vap, scan); if (ss->ss_ops != NULL) { /* XXX verify ss_ops matches vap->iv_opmode */ if ((flags & IEEE80211_SCAN_NOSSID) == 0) { /* * Update the ssid list and mark flags so if * we call start_scan it doesn't duplicate work. */ copy_ssid(vap, ss, nssid, ssids); flags |= IEEE80211_SCAN_NOSSID; } if ((ic->ic_flags & IEEE80211_F_SCAN) == 0 && (flags & IEEE80211_SCAN_FLUSH) == 0 && time_before(ticks, ic->ic_lastscan + vap->iv_scanvalid)) { /* * We're not currently scanning and the cache is * deemed hot enough to consult. Lock out others * by marking IEEE80211_F_SCAN while we decide if * something is already in the scan cache we can * use. Also discard any frames that might come * in while temporarily marked as scanning. */ SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD; ic->ic_flags |= IEEE80211_F_SCAN; /* NB: need to use supplied flags in check below */ ss->ss_flags = flags & 0xff; checkscanlist = 1; } } if (checkscanlist) { if (ss->ss_ops->scan_end(ss, vap)) { /* found an ap, just clear the flag */ ic->ic_flags &= ~IEEE80211_F_SCAN; ieee80211_notify_scan_done(vap); IEEE80211_UNLOCK(ic); return 1; } /* no ap, clear the flag before starting a scan */ ic->ic_flags &= ~IEEE80211_F_SCAN; } result = start_scan_locked(scan, vap, flags, duration, mindwell, maxdwell, nssid, ssids); IEEE80211_UNLOCK(ic); return result; } /* * Check the scan cache for an ap/channel to use; if that fails * then kick off a scan using the current settings. */ int ieee80211_check_scan_current(struct ieee80211vap *vap) { return ieee80211_check_scan(vap, IEEE80211_SCAN_ACTIVE, IEEE80211_SCAN_FOREVER, 0, 0, vap->iv_des_nssid, vap->iv_des_ssid); } /* * Restart a previous scan. If the previous scan completed * then we start again using the existing channel list. */ int ieee80211_bg_scan(struct ieee80211vap *vap, int flags) { struct ieee80211com *ic = vap->iv_ic; struct ieee80211_scan_state *ss = ic->ic_scan; const struct ieee80211_scanner *scan; scan = ieee80211_scanner_get(vap->iv_opmode); if (scan == NULL) { IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: no scanner support for %s mode\n", __func__, vap->iv_opmode); /* XXX stat */ return 0; } IEEE80211_LOCK(ic); if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) { u_int duration; /* * Go off-channel for a fixed interval that is large * enough to catch most ap's but short enough that * we can return on-channel before our listen interval * expires. */ duration = IEEE80211_SCAN_OFFCHANNEL; IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: %s scan, ticks %u duration %lu\n", __func__, ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive", ticks, duration); scan_update_locked(vap, scan); if (ss->ss_ops != NULL) { ss->ss_vap = vap; /* * A background scan does not select a new sta; it * just refreshes the scan cache. Also, indicate * the scan logic should follow the beacon schedule: * we go off-channel and scan for a while, then * return to the bss channel to receive a beacon, * then go off-channel again. All during this time * we notify the ap we're in power save mode. When * the scan is complete we leave power save mode. * If any beacon indicates there are frames pending * for us then we drop out of power save mode * (and background scan) automatically by way of the * usual sta power save logic. */ ss->ss_flags |= IEEE80211_SCAN_NOPICK | IEEE80211_SCAN_BGSCAN | flags ; /* if previous scan completed, restart */ if (ss->ss_next >= ss->ss_last) { if (ss->ss_flags & IEEE80211_SCAN_ACTIVE) vap->iv_stats.is_scan_active++; else vap->iv_stats.is_scan_passive++; /* * NB: beware of the scan cache being flushed; * if the channel list is empty use the * scan_start method to populate it. */ ss->ss_next = 0; if (ss->ss_last != 0) ss->ss_ops->scan_restart(ss, vap); else { ss->ss_ops->scan_start(ss, vap); #ifdef IEEE80211_DEBUG if (ieee80211_msg_scan(vap)) scan_dump(ss); #endif /* IEEE80211_DEBUG */ } } /* NB: flush frames rx'd before 1st channel change */ SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD; ss->ss_maxdwell = duration; if (scan_restart(SCAN_PRIVATE(ss), duration)) { ic->ic_flags |= IEEE80211_F_SCAN; ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN; } } else { /* XXX msg+stat */ } } else { IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: %s scan already in progress\n", __func__, ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"); } IEEE80211_UNLOCK(ic); /* NB: racey, does it matter? */ return (ic->ic_flags & IEEE80211_F_SCAN); } /* * Cancel any scan currently going on for the specified vap. */ void ieee80211_cancel_scan(struct ieee80211vap *vap) { struct ieee80211com *ic = vap->iv_ic; struct ieee80211_scan_state *ss = ic->ic_scan; IEEE80211_LOCK(ic); if ((ic->ic_flags & IEEE80211_F_SCAN) && ss->ss_vap == vap && (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) { IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: cancel %s scan\n", __func__, ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"); /* clear bg scan NOPICK and mark cancel request */ ss->ss_flags &= ~IEEE80211_SCAN_NOPICK; SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL; /* force it to fire asap */ callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer, 0, scan_next, ss); } IEEE80211_UNLOCK(ic); } /* * Cancel any scan currently going on. */ void ieee80211_cancel_anyscan(struct ieee80211vap *vap) { struct ieee80211com *ic = vap->iv_ic; struct ieee80211_scan_state *ss = ic->ic_scan; IEEE80211_LOCK(ic); if ((ic->ic_flags & IEEE80211_F_SCAN) && (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0) { IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: cancel %s scan\n", __func__, ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive"); /* clear bg scan NOPICK and mark cancel request */ ss->ss_flags &= ~IEEE80211_SCAN_NOPICK; SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL; /* force it to fire asap */ callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer, 0, scan_next, ss); } IEEE80211_UNLOCK(ic); } /* * Public access to scan_next for drivers that manage * scanning themselves (e.g. for firmware-based devices). */ void ieee80211_scan_next(struct ieee80211vap *vap) { struct ieee80211com *ic = vap->iv_ic; struct ieee80211_scan_state *ss = ic->ic_scan; callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer, 0, scan_next, ss); } /* * Public access to scan_next for drivers that are not able to scan single * channels (e.g. for firmware-based devices). */ void ieee80211_scan_done(struct ieee80211vap *vap) { struct ieee80211com *ic = vap->iv_ic; struct ieee80211_scan_state *ss; IEEE80211_LOCK(ic); ss = ic->ic_scan; ss->ss_next = ss->ss_last; /* all channels are complete */ scan_next(ss); IEEE80211_UNLOCK(ic); } /* * Probe the curent channel, if allowed, while scanning. * If the channel is not marked passive-only then send * a probe request immediately. Otherwise mark state and * listen for beacons on the channel; if we receive something * then we'll transmit a probe request. */ void ieee80211_probe_curchan(struct ieee80211vap *vap, int force) { struct ieee80211com *ic = vap->iv_ic; struct ieee80211_scan_state *ss = ic->ic_scan; struct ifnet *ifp = vap->iv_ifp; int i; if ((ic->ic_curchan->ic_flags & IEEE80211_CHAN_PASSIVE) && !force) { ic->ic_flags_ext |= IEEE80211_FEXT_PROBECHAN; return; } /* * Send directed probe requests followed by any * broadcast probe request. * XXX remove dependence on ic/vap->iv_bss */ for (i = 0; i < ss->ss_nssid; i++) ieee80211_send_probereq(vap->iv_bss, vap->iv_myaddr, ifp->if_broadcastaddr, ifp->if_broadcastaddr, ss->ss_ssid[i].ssid, ss->ss_ssid[i].len); if ((ss->ss_flags & IEEE80211_SCAN_NOBCAST) == 0) ieee80211_send_probereq(vap->iv_bss, vap->iv_myaddr, ifp->if_broadcastaddr, ifp->if_broadcastaddr, "", 0); } /* * Scan curchan. If this is an active scan and the channel * is not marked passive then send probe request frame(s). * Arrange for the channel change after maxdwell ticks. */ static void scan_curchan(struct ieee80211_scan_state *ss, unsigned long maxdwell) { struct ieee80211vap *vap = ss->ss_vap; IEEE80211_LOCK_ASSERT(vap->iv_ic); if (ss->ss_flags & IEEE80211_SCAN_ACTIVE) ieee80211_probe_curchan(vap, 0); callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer, maxdwell, scan_next, ss); } /* * Handle mindwell requirements completed; initiate a channel * change to the next channel asap. */ static void scan_mindwell(struct ieee80211_scan_state *ss) { callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer, 0, scan_next, ss); } /* * Switch to the next channel marked for scanning. */ static void scan_next(void *arg) { #define ISCAN_REP (ISCAN_MINDWELL | ISCAN_START | ISCAN_DISCARD) struct ieee80211_scan_state *ss = (struct ieee80211_scan_state *) arg; struct ieee80211vap *vap = ss->ss_vap; struct ieee80211com *ic = vap->iv_ic; struct ieee80211_channel *chan; unsigned long maxdwell, scanend; int scandone; IEEE80211_LOCK_ASSERT(ic); if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) return; again: scandone = (ss->ss_next >= ss->ss_last) || (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) != 0; scanend = SCAN_PRIVATE(ss)->ss_scanend; if (!scandone && (ss->ss_flags & IEEE80211_SCAN_GOTPICK) == 0 && ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_START) || time_before(ticks + ss->ss_mindwell, scanend))) { chan = ss->ss_chans[ss->ss_next++]; /* * Watch for truncation due to the scan end time. */ if (time_after(ticks + ss->ss_maxdwell, scanend)) maxdwell = scanend - ticks; else maxdwell = ss->ss_maxdwell; IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: chan %3d%c -> %3d%c [%s, dwell min %lu max %lu]\n", __func__, ieee80211_chan2ieee(ic, ic->ic_curchan), channel_type(ic->ic_curchan), ieee80211_chan2ieee(ic, chan), channel_type(chan), (ss->ss_flags & IEEE80211_SCAN_ACTIVE) && (chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0 ? "active" : "passive", ss->ss_mindwell, maxdwell); /* * Potentially change channel and phy mode. */ change_channel(ic, chan); /* * Scan curchan. Drivers for "intelligent hardware" * override ic_scan_curchan to tell the device to do * the work. Otherwise we manage the work outselves; * sending a probe request (as needed), and arming the * timeout to switch channels after maxdwell ticks. */ ic->ic_scan_curchan(ss, maxdwell); SCAN_PRIVATE(ss)->ss_chanmindwell = ticks + ss->ss_mindwell; /* clear mindwell lock and initial channel change flush */ SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP; } else { ic->ic_scan_end(ic); /* notify driver */ /* * Record scan complete time. Note that we also do * this when canceled so any background scan will * not be restarted for a while. */ if (scandone) ic->ic_lastscan = ticks; /* return to the bss channel */ if (ic->ic_bsschan != IEEE80211_CHAN_ANYC && ic->ic_curchan != ic->ic_bsschan) ieee80211_setcurchan(ic, ic->ic_bsschan); /* clear internal flags and any indication of a pick */ SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_REP; ss->ss_flags &= ~IEEE80211_SCAN_GOTPICK; /* * If not canceled and scan completed, do post-processing. * If the callback function returns 0, then it wants to * continue/restart scanning. Unfortunately we needed to * notify the driver to end the scan above to avoid having * rx frames alter the scan candidate list. */ if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_CANCEL) == 0 && !ss->ss_ops->scan_end(ss, vap) && (ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 && time_before(ticks + ss->ss_mindwell, scanend)) { IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: done, restart " "[ticks %u, dwell min %lu scanend %lu]\n", __func__, ticks, ss->ss_mindwell, scanend); ss->ss_next = 0; /* reset to begining */ if (ss->ss_flags & IEEE80211_SCAN_ACTIVE) vap->iv_stats.is_scan_active++; else vap->iv_stats.is_scan_passive++; ss->ss_ops->scan_restart(ss, vap); /* XXX? */ ic->ic_scan_start(ic); /* notify driver */ goto again; } else { /* past here, scandone is ``true'' if not in bg mode */ if ((ss->ss_flags & IEEE80211_SCAN_BGSCAN) == 0) scandone = 1; IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: %s, " "[ticks %u, dwell min %lu scanend %lu]\n", __func__, scandone ? "done" : "stopped", ticks, ss->ss_mindwell, scanend); /* * Clear the SCAN bit first in case frames are * pending on the station power save queue. If * we defer this then the dispatch of the frames * may generate a request to cancel scanning. */ ic->ic_flags &= ~IEEE80211_F_SCAN; /* * Drop out of power save mode when a scan has * completed. If this scan was prematurely terminated * because it is a background scan then don't notify * the ap; we'll either return to scanning after we * receive the beacon frame or we'll drop out of power * save mode because the beacon indicates we have frames * waiting for us. */ if (scandone) { ieee80211_sta_pwrsave(vap, 0); if (ss->ss_next >= ss->ss_last) { ieee80211_notify_scan_done(vap); ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN; } } SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_CANCEL; ss->ss_flags &= ~(IEEE80211_SCAN_ONCE | IEEE80211_SCAN_PICK1ST); } } #undef ISCAN_REP } #ifdef IEEE80211_DEBUG static void dump_country(const uint8_t *ie) { const struct ieee80211_country_ie *cie = (const struct ieee80211_country_ie *) ie; int i, nbands, schan, nchan; if (cie->len < 3) { printf(" ", cie->len); return; } printf(" country [%c%c%c", cie->cc[0], cie->cc[1], cie->cc[2]); nbands = (cie->len - 3) / sizeof(cie->band[0]); for (i = 0; i < nbands; i++) { schan = cie->band[i].schan; nchan = cie->band[i].nchan; if (nchan != 1) printf(" %u-%u,%u", schan, schan + nchan-1, cie->band[i].maxtxpwr); else printf(" %u,%u", schan, cie->band[i].maxtxpwr); } printf("]"); } static void dump_probe_beacon(uint8_t subtype, int isnew, const uint8_t mac[IEEE80211_ADDR_LEN], const struct ieee80211_scanparams *sp, int rssi) { printf("[%s] %s%s on chan %u (bss chan %u) ", ether_sprintf(mac), isnew ? "new " : "", ieee80211_mgt_subtype_name[subtype >> IEEE80211_FC0_SUBTYPE_SHIFT], sp->chan, sp->bchan); ieee80211_print_essid(sp->ssid + 2, sp->ssid[1]); printf(" rssi %d\n", rssi); if (isnew) { printf("[%s] caps 0x%x bintval %u erp 0x%x", ether_sprintf(mac), sp->capinfo, sp->bintval, sp->erp); if (sp->country != NULL) dump_country(sp->country); printf("\n"); } } #endif /* IEEE80211_DEBUG */ /* * Process a beacon or probe response frame. */ void ieee80211_add_scan(struct ieee80211vap *vap, const struct ieee80211_scanparams *sp, const struct ieee80211_frame *wh, int subtype, int rssi, int noise, int rstamp) { struct ieee80211com *ic = vap->iv_ic; struct ieee80211_scan_state *ss = ic->ic_scan; /* XXX locking */ /* * Frames received during startup are discarded to avoid * using scan state setup on the initial entry to the timer * callback. This can occur because the device may enable * rx prior to our doing the initial channel change in the * timer routine. */ if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD) return; #ifdef IEEE80211_DEBUG if (ieee80211_msg_scan(vap) && (ic->ic_flags & IEEE80211_F_SCAN)) dump_probe_beacon(subtype, 1, wh->i_addr2, sp, rssi); #endif if (ss->ss_ops != NULL && ss->ss_ops->scan_add(ss, sp, wh, subtype, rssi, noise, rstamp)) { /* * If we've reached the min dwell time terminate * the timer so we'll switch to the next channel. */ if ((SCAN_PRIVATE(ss)->ss_iflags & ISCAN_MINDWELL) == 0 && time_after_eq(ticks, SCAN_PRIVATE(ss)->ss_chanmindwell)) { IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s: chan %3d%c min dwell met (%u > %lu)\n", __func__, ieee80211_chan2ieee(ic, ic->ic_curchan), channel_type(ic->ic_curchan), ticks, SCAN_PRIVATE(ss)->ss_chanmindwell); SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL; /* * NB: trigger at next clock tick or wait for the * hardware. */ ic->ic_scan_mindwell(ss); } } } /* * Timeout/age scan cache entries; called from sta timeout * timer (XXX should be self-contained). */ void ieee80211_scan_timeout(struct ieee80211com *ic) { struct ieee80211_scan_state *ss = ic->ic_scan; if (ss->ss_ops != NULL) ss->ss_ops->scan_age(ss); } /* * Mark a scan cache entry after a successful associate. */ void ieee80211_scan_assoc_success(struct ieee80211vap *vap, const uint8_t mac[]) { struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan; if (ss->ss_ops != NULL) { IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN, mac, "%s", __func__); ss->ss_ops->scan_assoc_success(ss, mac); } } /* * Demerit a scan cache entry after failing to associate. */ void ieee80211_scan_assoc_fail(struct ieee80211vap *vap, const uint8_t mac[], int reason) { struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan; if (ss->ss_ops != NULL) { IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_SCAN, mac, "%s: reason %u", __func__, reason); ss->ss_ops->scan_assoc_fail(ss, mac, reason); } } /* * Iterate over the contents of the scan cache. */ void ieee80211_scan_iterate(struct ieee80211vap *vap, ieee80211_scan_iter_func *f, void *arg) { struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan; if (ss->ss_ops != NULL) ss->ss_ops->scan_iterate(ss, f, arg); } /* * Flush the contents of the scan cache. */ void ieee80211_scan_flush(struct ieee80211vap *vap) { struct ieee80211_scan_state *ss = vap->iv_ic->ic_scan; if (ss->ss_ops != NULL && ss->ss_vap == vap) { IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN, "%s\n", __func__); ss->ss_ops->scan_flush(ss); } } /* * Check the scan cache for an ap/channel to use; if that * fails then kick off a new scan. */ struct ieee80211_channel * ieee80211_scan_pickchannel(struct ieee80211com *ic, int flags) { struct ieee80211_scan_state *ss = ic->ic_scan; IEEE80211_LOCK_ASSERT(ic); if (ss == NULL || ss->ss_ops == NULL || ss->ss_vap == NULL) { /* XXX printf? */ return NULL; } if (ss->ss_ops->scan_pickchan == NULL) { IEEE80211_DPRINTF(ss->ss_vap, IEEE80211_MSG_SCAN, "%s: scan module does not support picking a channel, " "opmode %s\n", __func__, ss->ss_vap->iv_opmode); return NULL; } return ss->ss_ops->scan_pickchan(ss, flags); }