/*- * Copyright (c) 2002-2007 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("$FreeBSD$"); /* * IEEE 802.11 station scanning support. */ #include #include #include #include #include #include #include #include #include #include /* * Parameters for managing cache entries: * * o a station with STA_FAILS_MAX failures is not considered * when picking a candidate * o a station that hasn't had an update in STA_PURGE_SCANS * (background) scans is discarded * o after STA_FAILS_AGE seconds we clear the failure count */ #define STA_FAILS_MAX 2 /* assoc failures before ignored */ #define STA_FAILS_AGE (2*60) /* time before clearing fails (secs) */ #define STA_PURGE_SCANS 2 /* age for purging entries (scans) */ /* XXX tunable */ #define STA_RSSI_MIN 8 /* min acceptable rssi */ #define STA_RSSI_MAX 40 /* max rssi for comparison */ #define RSSI_LPF_LEN 10 #define RSSI_DUMMY_MARKER 0x127 #define RSSI_EP_MULTIPLIER (1<<7) /* pow2 to optimize out * and / */ #define RSSI_IN(x) ((x) * RSSI_EP_MULTIPLIER) #define LPF_RSSI(x, y, len) \ ((x != RSSI_DUMMY_MARKER) ? (((x) * ((len) - 1) + (y)) / (len)) : (y)) #define RSSI_LPF(x, y) do { \ if ((y) >= -20) \ x = LPF_RSSI((x), RSSI_IN((y)), RSSI_LPF_LEN); \ } while (0) #define EP_RND(x, mul) \ ((((x)%(mul)) >= ((mul)/2)) ? howmany(x, mul) : (x)/(mul)) #define RSSI_GET(x) EP_RND(x, RSSI_EP_MULTIPLIER) struct sta_entry { struct ieee80211_scan_entry base; TAILQ_ENTRY(sta_entry) se_list; LIST_ENTRY(sta_entry) se_hash; uint8_t se_fails; /* failure to associate count */ uint8_t se_seen; /* seen during current scan */ uint8_t se_notseen; /* not seen in previous scans */ uint8_t se_flags; uint32_t se_avgrssi; /* LPF rssi state */ unsigned long se_lastupdate; /* time of last update */ unsigned long se_lastfail; /* time of last failure */ unsigned long se_lastassoc; /* time of last association */ u_int se_scangen; /* iterator scan gen# */ }; #define STA_HASHSIZE 32 /* simple hash is enough for variation of macaddr */ #define STA_HASH(addr) \ (((const uint8_t *)(addr))[IEEE80211_ADDR_LEN - 1] % STA_HASHSIZE) struct sta_table { struct mtx st_lock; /* on scan table */ TAILQ_HEAD(, sta_entry) st_entry; /* all entries */ LIST_HEAD(, sta_entry) st_hash[STA_HASHSIZE]; struct mtx st_scanlock; /* on st_scangen */ u_int st_scangen; /* gen# for iterator */ int st_newscan; }; static void sta_flush_table(struct sta_table *); /* * match_bss returns a bitmask describing if an entry is suitable * for use. If non-zero the entry was deemed not suitable and it's * contents explains why. The following flags are or'd to to this * mask and can be used to figure out why the entry was rejected. */ #define MATCH_CHANNEL 0x001 /* channel mismatch */ #define MATCH_CAPINFO 0x002 /* capabilities mismatch, e.g. no ess */ #define MATCH_PRIVACY 0x004 /* privacy mismatch */ #define MATCH_RATE 0x008 /* rate set mismatch */ #define MATCH_SSID 0x010 /* ssid mismatch */ #define MATCH_BSSID 0x020 /* bssid mismatch */ #define MATCH_FAILS 0x040 /* too many failed auth attempts */ #define MATCH_NOTSEEN 0x080 /* not seen in recent scans */ #define MATCH_RSSI 0x100 /* rssi deemed too low to use */ static int match_bss(struct ieee80211com *, const struct ieee80211_scan_state *, struct sta_entry *, int); /* number of references from net80211 layer */ static int nrefs = 0; /* * Attach prior to any scanning work. */ static int sta_attach(struct ieee80211_scan_state *ss) { struct sta_table *st; MALLOC(st, struct sta_table *, sizeof(struct sta_table), M_80211_SCAN, M_NOWAIT | M_ZERO); if (st == NULL) return 0; mtx_init(&st->st_lock, "scantable", "802.11 scan table", MTX_DEF); mtx_init(&st->st_scanlock, "scangen", "802.11 scangen", MTX_DEF); TAILQ_INIT(&st->st_entry); ss->ss_priv = st; nrefs++; /* NB: we assume caller locking */ return 1; } /* * Cleanup any private state. */ static int sta_detach(struct ieee80211_scan_state *ss) { struct sta_table *st = ss->ss_priv; if (st != NULL) { sta_flush_table(st); mtx_destroy(&st->st_lock); mtx_destroy(&st->st_scanlock); FREE(st, M_80211_SCAN); KASSERT(nrefs > 0, ("imbalanced attach/detach")); nrefs--; /* NB: we assume caller locking */ } return 1; } /* * Flush all per-scan state. */ static int sta_flush(struct ieee80211_scan_state *ss) { struct sta_table *st = ss->ss_priv; mtx_lock(&st->st_lock); sta_flush_table(st); mtx_unlock(&st->st_lock); ss->ss_last = 0; return 0; } /* * Flush all entries in the scan cache. */ static void sta_flush_table(struct sta_table *st) { struct sta_entry *se, *next; TAILQ_FOREACH_SAFE(se, &st->st_entry, se_list, next) { TAILQ_REMOVE(&st->st_entry, se, se_list); LIST_REMOVE(se, se_hash); FREE(se, M_80211_SCAN); } } static void saveie(uint8_t **iep, const uint8_t *ie) { if (ie == NULL) *iep = NULL; else ieee80211_saveie(iep, ie); } /* * Process a beacon or probe response frame; create an * entry in the scan cache or update any previous entry. */ static int sta_add(struct ieee80211_scan_state *ss, const struct ieee80211_scanparams *sp, const struct ieee80211_frame *wh, int subtype, int rssi, int noise, int rstamp) { #define ISPROBE(_st) ((_st) == IEEE80211_FC0_SUBTYPE_PROBE_RESP) #define PICK1ST(_ss) \ ((ss->ss_flags & (IEEE80211_SCAN_PICK1ST | IEEE80211_SCAN_GOTPICK)) == \ IEEE80211_SCAN_PICK1ST) struct sta_table *st = ss->ss_priv; const uint8_t *macaddr = wh->i_addr2; struct ieee80211com *ic = ss->ss_ic; struct sta_entry *se; struct ieee80211_scan_entry *ise; int hash, offchan; hash = STA_HASH(macaddr); mtx_lock(&st->st_lock); LIST_FOREACH(se, &st->st_hash[hash], se_hash) if (IEEE80211_ADDR_EQ(se->base.se_macaddr, macaddr)) goto found; MALLOC(se, struct sta_entry *, sizeof(struct sta_entry), M_80211_SCAN, M_NOWAIT | M_ZERO); if (se == NULL) { mtx_unlock(&st->st_lock); return 0; } se->se_scangen = st->st_scangen-1; se->se_avgrssi = RSSI_DUMMY_MARKER; IEEE80211_ADDR_COPY(se->base.se_macaddr, macaddr); TAILQ_INSERT_TAIL(&st->st_entry, se, se_list); LIST_INSERT_HEAD(&st->st_hash[hash], se, se_hash); found: ise = &se->base; /* XXX ap beaconing multiple ssid w/ same bssid */ if (sp->ssid[1] != 0 && (ISPROBE(subtype) || ise->se_ssid[1] == 0)) memcpy(ise->se_ssid, sp->ssid, 2+sp->ssid[1]); KASSERT(sp->rates[1] <= IEEE80211_RATE_MAXSIZE, ("rate set too large: %u", sp->rates[1])); memcpy(ise->se_rates, sp->rates, 2+sp->rates[1]); if (sp->xrates != NULL) { /* XXX validate xrates[1] */ KASSERT(sp->xrates[1] + sp->rates[1] <= IEEE80211_RATE_MAXSIZE, ("xrate set too large: %u", sp->xrates[1])); memcpy(ise->se_xrates, sp->xrates, 2+sp->xrates[1]); } else ise->se_xrates[1] = 0; IEEE80211_ADDR_COPY(ise->se_bssid, wh->i_addr3); offchan = (IEEE80211_CHAN2IEEE(sp->curchan) != sp->bchan && ic->ic_phytype != IEEE80211_T_FH); if (!offchan) { /* * Record rssi data using extended precision LPF filter. * * NB: use only on-channel data to insure we get a good * estimate of the signal we'll see when associated. */ RSSI_LPF(se->se_avgrssi, rssi); ise->se_rssi = RSSI_GET(se->se_avgrssi); ise->se_noise = noise; } ise->se_rstamp = rstamp; memcpy(ise->se_tstamp.data, sp->tstamp, sizeof(ise->se_tstamp)); ise->se_intval = sp->bintval; ise->se_capinfo = sp->capinfo; /* * Beware of overriding se_chan for frames seen * off-channel; this can cause us to attempt an * assocation on the wrong channel. */ if (offchan) { struct ieee80211_channel *c; /* * Off-channel, locate the home/bss channel for the sta * using the value broadcast in the DSPARMS ie. */ c = ieee80211_find_channel_byieee(ic, sp->bchan, sp->curchan->ic_flags); if (c != NULL) { ise->se_chan = c; } else if (ise->se_chan == NULL) { /* should not happen, pick something */ ise->se_chan = sp->curchan; } } else ise->se_chan = sp->curchan; ise->se_fhdwell = sp->fhdwell; ise->se_fhindex = sp->fhindex; ise->se_erp = sp->erp; ise->se_timoff = sp->timoff; if (sp->tim != NULL) { const struct ieee80211_tim_ie *tim = (const struct ieee80211_tim_ie *) sp->tim; ise->se_dtimperiod = tim->tim_period; } saveie(&ise->se_wme_ie, sp->wme); saveie(&ise->se_wpa_ie, sp->wpa); saveie(&ise->se_rsn_ie, sp->rsn); saveie(&ise->se_ath_ie, sp->ath); saveie(&ise->se_htcap_ie, sp->htcap); saveie(&ise->se_htinfo_ie, sp->htinfo); /* clear failure count after STA_FAIL_AGE passes */ if (se->se_fails && (ticks - se->se_lastfail) > STA_FAILS_AGE*hz) { se->se_fails = 0; IEEE80211_NOTE_MAC(ic, IEEE80211_MSG_SCAN, macaddr, "%s: fails %u", __func__, se->se_fails); } se->se_lastupdate = ticks; /* update time */ se->se_seen = 1; se->se_notseen = 0; mtx_unlock(&st->st_lock); /* * If looking for a quick choice and nothing's * been found check here. */ if (PICK1ST(ss) && match_bss(ic, ss, se, IEEE80211_MSG_SCAN) == 0) ss->ss_flags |= IEEE80211_SCAN_GOTPICK; return 1; #undef PICK1ST #undef ISPROBE } /* * Check if a channel is excluded by user request. */ static int isexcluded(struct ieee80211com *ic, const struct ieee80211_channel *c) { return (isclr(ic->ic_chan_active, c->ic_ieee) || (ic->ic_des_chan != IEEE80211_CHAN_ANYC && c->ic_freq != ic->ic_des_chan->ic_freq)); } static struct ieee80211_channel * find11gchannel(struct ieee80211com *ic, int i, int freq) { struct ieee80211_channel *c; int j; /* * The normal ordering in the channel list is b channel * immediately followed by g so optimize the search for * this. We'll still do a full search just in case. */ for (j = i+1; j < ic->ic_nchans; j++) { c = &ic->ic_channels[j]; if (c->ic_freq == freq && IEEE80211_IS_CHAN_ANYG(c)) return c; } for (j = 0; j < i; j++) { c = &ic->ic_channels[j]; if (c->ic_freq == freq && IEEE80211_IS_CHAN_ANYG(c)) return c; } return NULL; } static const u_int chanflags[IEEE80211_MODE_MAX] = { IEEE80211_CHAN_B, /* IEEE80211_MODE_AUTO */ IEEE80211_CHAN_A, /* IEEE80211_MODE_11A */ IEEE80211_CHAN_B, /* IEEE80211_MODE_11B */ IEEE80211_CHAN_G, /* IEEE80211_MODE_11G */ IEEE80211_CHAN_FHSS, /* IEEE80211_MODE_FH */ IEEE80211_CHAN_A, /* IEEE80211_MODE_TURBO_A (check base channel)*/ IEEE80211_CHAN_G, /* IEEE80211_MODE_TURBO_G */ IEEE80211_CHAN_ST, /* IEEE80211_MODE_STURBO_A */ IEEE80211_CHAN_A, /* IEEE80211_MODE_11NA (check legacy) */ IEEE80211_CHAN_G, /* IEEE80211_MODE_11NG (check legacy) */ }; static void add_channels(struct ieee80211com *ic, struct ieee80211_scan_state *ss, enum ieee80211_phymode mode, const uint16_t freq[], int nfreq) { #define N(a) (sizeof(a) / sizeof(a[0])) struct ieee80211_channel *c, *cg; u_int modeflags; int i; KASSERT(mode < N(chanflags), ("Unexpected mode %u", mode)); modeflags = chanflags[mode]; for (i = 0; i < nfreq; i++) { if (ss->ss_last >= IEEE80211_SCAN_MAX) break; c = ieee80211_find_channel(ic, freq[i], modeflags); if (c != NULL && isexcluded(ic, c)) continue; if (mode == IEEE80211_MODE_AUTO) { /* * XXX special-case 11b/g channels so we select * the g channel if both are present or there * are only g channels. */ if (c == NULL || IEEE80211_IS_CHAN_B(c)) { cg = find11gchannel(ic, i, freq[i]); if (cg != NULL) c = cg; } } if (c == NULL) continue; ss->ss_chans[ss->ss_last++] = c; } #undef N } static const uint16_t rcl1[] = /* 8 FCC channel: 52, 56, 60, 64, 36, 40, 44, 48 */ { 5260, 5280, 5300, 5320, 5180, 5200, 5220, 5240 }; static const uint16_t rcl2[] = /* 4 MKK channels: 34, 38, 42, 46 */ { 5170, 5190, 5210, 5230 }; static const uint16_t rcl3[] = /* 2.4Ghz ch: 1,6,11,7,13 */ { 2412, 2437, 2462, 2442, 2472 }; static const uint16_t rcl4[] = /* 5 FCC channel: 149, 153, 161, 165 */ { 5745, 5765, 5785, 5805, 5825 }; static const uint16_t rcl7[] = /* 11 ETSI channel: 100,104,108,112,116,120,124,128,132,136,140 */ { 5500, 5520, 5540, 5560, 5580, 5600, 5620, 5640, 5660, 5680, 5700 }; static const uint16_t rcl8[] = /* 2.4Ghz ch: 2,3,4,5,8,9,10,12 */ { 2417, 2422, 2427, 2432, 2447, 2452, 2457, 2467 }; static const uint16_t rcl9[] = /* 2.4Ghz ch: 14 */ { 2484 }; static const uint16_t rcl10[] = /* Added Korean channels 2312-2372 */ { 2312, 2317, 2322, 2327, 2332, 2337, 2342, 2347, 2352, 2357, 2362, 2367, 2372 }; static const uint16_t rcl11[] = /* Added Japan channels in 4.9/5.0 spectrum */ { 5040, 5060, 5080, 4920, 4940, 4960, 4980 }; #ifdef ATH_TURBO_SCAN static const uint16_t rcl5[] = /* 3 static turbo channels */ { 5210, 5250, 5290 }; static const uint16_t rcl6[] = /* 2 static turbo channels */ { 5760, 5800 }; static const uint16_t rcl6x[] = /* 4 FCC3 turbo channels */ { 5540, 5580, 5620, 5660 }; static const uint16_t rcl12[] = /* 2.4Ghz Turbo channel 6 */ { 2437 }; static const uint16_t rcl13[] = /* dynamic Turbo channels */ { 5200, 5240, 5280, 5765, 5805 }; #endif /* ATH_TURBO_SCAN */ struct scanlist { uint16_t mode; uint16_t count; const uint16_t *list; }; #define X(a) .count = sizeof(a)/sizeof(a[0]), .list = a static const struct scanlist staScanTable[] = { { IEEE80211_MODE_11B, X(rcl3) }, { IEEE80211_MODE_11A, X(rcl1) }, { IEEE80211_MODE_11A, X(rcl2) }, { IEEE80211_MODE_11B, X(rcl8) }, { IEEE80211_MODE_11B, X(rcl9) }, { IEEE80211_MODE_11A, X(rcl4) }, #ifdef ATH_TURBO_SCAN { IEEE80211_MODE_STURBO_A, X(rcl5) }, { IEEE80211_MODE_STURBO_A, X(rcl6) }, { IEEE80211_MODE_TURBO_A, X(rcl6x) }, { IEEE80211_MODE_TURBO_A, X(rcl13) }, #endif /* ATH_TURBO_SCAN */ { IEEE80211_MODE_11A, X(rcl7) }, { IEEE80211_MODE_11B, X(rcl10) }, { IEEE80211_MODE_11A, X(rcl11) }, #ifdef ATH_TURBO_SCAN { IEEE80211_MODE_TURBO_G, X(rcl12) }, #endif /* ATH_TURBO_SCAN */ { .list = NULL } }; static int checktable(const struct scanlist *scan, const struct ieee80211_channel *c) { int i; for (; scan->list != NULL; scan++) { for (i = 0; i < scan->count; i++) if (scan->list[i] == c->ic_freq) return 1; } return 0; } static void sweepchannels(struct ieee80211_scan_state *ss, struct ieee80211com *ic, const struct scanlist table[]) { struct ieee80211_channel *c; int i; /* * Add the channels from the ic (from HAL) that are not present * in the staScanTable. */ for (i = 0; i < ic->ic_nchans; i++) { if (ss->ss_last >= IEEE80211_SCAN_MAX) break; c = &ic->ic_channels[i]; /* * Ignore dynamic turbo channels; we scan them * in normal mode (i.e. not boosted). Likewise * for HT channels, they get scanned using * legacy rates. */ if (IEEE80211_IS_CHAN_DTURBO(c) || IEEE80211_IS_CHAN_HT(c)) continue; /* * If a desired mode was specified, scan only * channels that satisfy that constraint. */ if (ic->ic_des_mode != IEEE80211_MODE_AUTO && ic->ic_des_mode != ieee80211_chan2mode(c)) continue; /* * Skip channels excluded by user request. */ if (isexcluded(ic, c)) continue; /* * Add the channel unless it is listed in the * fixed scan order tables. This insures we * don't sweep back in channels we filtered out * above. */ if (checktable(table, c)) continue; /* Add channel to scanning list. */ ss->ss_chans[ss->ss_last++] = c; } } /* * Start a station-mode scan by populating the channel list. */ static int sta_start(struct ieee80211_scan_state *ss, struct ieee80211com *ic) { #define N(a) (sizeof(a)/sizeof(a[0])) struct sta_table *st = ss->ss_priv; const struct scanlist *scan; enum ieee80211_phymode mode; ss->ss_last = 0; /* * Use the table of ordered channels to construct the list * of channels for scanning. Any channels in the ordered * list not in the master list will be discarded. */ for (scan = staScanTable; scan->list != NULL; scan++) { mode = scan->mode; if (ic->ic_des_mode != IEEE80211_MODE_AUTO) { /* * If a desired mode was specified, scan only * channels that satisfy that constraint. */ if (ic->ic_des_mode != mode) { /* * The scan table marks 2.4Ghz channels as b * so if the desired mode is 11g, then use * the 11b channel list but upgrade the mode. */ if (ic->ic_des_mode != IEEE80211_MODE_11G || mode != IEEE80211_MODE_11B) continue; mode = IEEE80211_MODE_11G; /* upgrade */ } } else { /* * This lets add_channels upgrade an 11b channel * to 11g if available. */ if (mode == IEEE80211_MODE_11B) mode = IEEE80211_MODE_AUTO; } #ifdef IEEE80211_F_XR /* XR does not operate on turbo channels */ if ((ic->ic_flags & IEEE80211_F_XR) && (mode == IEEE80211_MODE_TURBO_A || mode == IEEE80211_MODE_TURBO_G || mode == IEEE80211_MODE_STURBO_A)) continue; #endif /* * Add the list of the channels; any that are not * in the master channel list will be discarded. */ add_channels(ic, ss, mode, scan->list, scan->count); } /* * Add the channels from the ic (from HAL) that are not present * in the staScanTable. */ sweepchannels(ss, ic, staScanTable); ss->ss_next = 0; /* XXX tunables */ ss->ss_mindwell = msecs_to_ticks(20); /* 20ms */ ss->ss_maxdwell = msecs_to_ticks(200); /* 200ms */ #ifdef IEEE80211_DEBUG if (ieee80211_msg_scan(ic)) { if_printf(ic->ic_ifp, "scan set "); ieee80211_scan_dump_channels(ss); printf(" dwell min %ld max %ld\n", ss->ss_mindwell, ss->ss_maxdwell); } #endif /* IEEE80211_DEBUG */ st->st_newscan = 1; return 0; #undef N } /* * Restart a bg scan. */ static int sta_restart(struct ieee80211_scan_state *ss, struct ieee80211com *ic) { struct sta_table *st = ss->ss_priv; st->st_newscan = 1; return 0; } /* * Cancel an ongoing scan. */ static int sta_cancel(struct ieee80211_scan_state *ss, struct ieee80211com *ic) { return 0; } static uint8_t maxrate(const struct ieee80211_scan_entry *se) { uint8_t rmax, r; int i; rmax = 0; for (i = 0; i < se->se_rates[1]; i++) { r = se->se_rates[2+i] & IEEE80211_RATE_VAL; if (r > rmax) rmax = r; } for (i = 0; i < se->se_xrates[1]; i++) { r = se->se_xrates[2+i] & IEEE80211_RATE_VAL; if (r > rmax) rmax = r; } return rmax; } /* * Compare the capabilities of two entries and decide which is * more desirable (return >0 if a is considered better). Note * that we assume compatibility/usability has already been checked * so we don't need to (e.g. validate whether privacy is supported). * Used to select the best scan candidate for association in a BSS. */ static int sta_compare(const struct sta_entry *a, const struct sta_entry *b) { #define PREFER(_a,_b,_what) do { \ if (((_a) ^ (_b)) & (_what)) \ return ((_a) & (_what)) ? 1 : -1; \ } while (0) uint8_t maxa, maxb; int8_t rssia, rssib; int weight; /* privacy support */ PREFER(a->base.se_capinfo, b->base.se_capinfo, IEEE80211_CAPINFO_PRIVACY); /* compare count of previous failures */ weight = b->se_fails - a->se_fails; if (abs(weight) > 1) return weight; /* * Compare rssi. If the two are considered equivalent * then fallback to other criteria. We threshold the * comparisons to avoid selecting an ap purely by rssi * when both values may be good but one ap is otherwise * more desirable (e.g. an 11b-only ap with stronger * signal than an 11g ap). */ rssia = MIN(a->base.se_rssi, STA_RSSI_MAX); rssib = MIN(b->base.se_rssi, STA_RSSI_MAX); if (abs(rssib - rssia) < 5) { /* best/max rate preferred if signal level close enough XXX */ maxa = maxrate(&a->base); maxb = maxrate(&b->base); if (maxa != maxb) return maxa - maxb; /* XXX use freq for channel preference */ /* for now just prefer 5Ghz band to all other bands */ if (IEEE80211_IS_CHAN_5GHZ(a->base.se_chan) && !IEEE80211_IS_CHAN_5GHZ(b->base.se_chan)) return 1; if (!IEEE80211_IS_CHAN_5GHZ(a->base.se_chan) && IEEE80211_IS_CHAN_5GHZ(b->base.se_chan)) return -1; } /* all things being equal, use signal level */ return a->base.se_rssi - b->base.se_rssi; #undef PREFER } /* * Check rate set suitability and return the best supported rate. */ static int check_rate(struct ieee80211com *ic, const struct ieee80211_scan_entry *se) { #define RV(v) ((v) & IEEE80211_RATE_VAL) const struct ieee80211_rateset *srs; int i, j, nrs, r, okrate, badrate, fixedrate; const uint8_t *rs; okrate = badrate = fixedrate = 0; srs = ieee80211_get_suprates(ic, se->se_chan); nrs = se->se_rates[1]; rs = se->se_rates+2; fixedrate = IEEE80211_FIXED_RATE_NONE; again: for (i = 0; i < nrs; i++) { r = RV(rs[i]); badrate = r; /* * Check any fixed rate is included. */ if (r == ic->ic_fixed_rate) fixedrate = r; /* * Check against our supported rates. */ for (j = 0; j < srs->rs_nrates; j++) if (r == RV(srs->rs_rates[j])) { if (r > okrate) /* NB: track max */ okrate = r; break; } if (j == srs->rs_nrates && (rs[i] & IEEE80211_RATE_BASIC)) { /* * Don't try joining a BSS, if we don't support * one of its basic rates. */ okrate = 0; goto back; } } if (rs == se->se_rates+2) { /* scan xrates too; sort of an algol68-style for loop */ nrs = se->se_xrates[1]; rs = se->se_xrates+2; goto again; } back: if (okrate == 0 || ic->ic_fixed_rate != fixedrate) return badrate | IEEE80211_RATE_BASIC; else return RV(okrate); #undef RV } static int match_ssid(const uint8_t *ie, int nssid, const struct ieee80211_scan_ssid ssids[]) { int i; for (i = 0; i < nssid; i++) { if (ie[1] == ssids[i].len && memcmp(ie+2, ssids[i].ssid, ie[1]) == 0) return 1; } return 0; } /* * Test a scan candidate for suitability/compatibility. */ static int match_bss(struct ieee80211com *ic, const struct ieee80211_scan_state *ss, struct sta_entry *se0, int debug) { struct ieee80211_scan_entry *se = &se0->base; uint8_t rate; int fail; fail = 0; if (isclr(ic->ic_chan_active, ieee80211_chan2ieee(ic, se->se_chan))) fail |= MATCH_CHANNEL; /* * NB: normally the desired mode is used to construct * the channel list, but it's possible for the scan * cache to include entries for stations outside this * list so we check the desired mode here to weed them * out. */ if (ic->ic_des_mode != IEEE80211_MODE_AUTO && (se->se_chan->ic_flags & IEEE80211_CHAN_ALLTURBO) != chanflags[ic->ic_des_mode]) fail |= MATCH_CHANNEL; if (ic->ic_opmode == IEEE80211_M_IBSS) { if ((se->se_capinfo & IEEE80211_CAPINFO_IBSS) == 0) fail |= MATCH_CAPINFO; } else { if ((se->se_capinfo & IEEE80211_CAPINFO_ESS) == 0) fail |= MATCH_CAPINFO; } if (ic->ic_flags & IEEE80211_F_PRIVACY) { if ((se->se_capinfo & IEEE80211_CAPINFO_PRIVACY) == 0) fail |= MATCH_PRIVACY; } else { /* XXX does this mean privacy is supported or required? */ if (se->se_capinfo & IEEE80211_CAPINFO_PRIVACY) fail |= MATCH_PRIVACY; } rate = check_rate(ic, se); if (rate & IEEE80211_RATE_BASIC) fail |= MATCH_RATE; if (ss->ss_nssid != 0 && !match_ssid(se->se_ssid, ss->ss_nssid, ss->ss_ssid)) fail |= MATCH_SSID; if ((ic->ic_flags & IEEE80211_F_DESBSSID) && !IEEE80211_ADDR_EQ(ic->ic_des_bssid, se->se_bssid)) fail |= MATCH_BSSID; if (se0->se_fails >= STA_FAILS_MAX) fail |= MATCH_FAILS; /* NB: entries may be present awaiting purge, skip */ if (se0->se_notseen >= STA_PURGE_SCANS) fail |= MATCH_NOTSEEN; if (se->se_rssi < STA_RSSI_MIN) fail |= MATCH_RSSI; #ifdef IEEE80211_DEBUG if (ieee80211_msg(ic, debug)) { printf(" %c %s", fail & MATCH_FAILS ? '=' : fail & MATCH_NOTSEEN ? '^' : fail ? '-' : '+', ether_sprintf(se->se_macaddr)); printf(" %s%c", ether_sprintf(se->se_bssid), fail & MATCH_BSSID ? '!' : ' '); printf(" %3d%c", ieee80211_chan2ieee(ic, se->se_chan), fail & MATCH_CHANNEL ? '!' : ' '); printf(" %+4d%c", se->se_rssi, fail & MATCH_RSSI ? '!' : ' '); printf(" %2dM%c", (rate & IEEE80211_RATE_VAL) / 2, fail & MATCH_RATE ? '!' : ' '); printf(" %4s%c", (se->se_capinfo & IEEE80211_CAPINFO_ESS) ? "ess" : (se->se_capinfo & IEEE80211_CAPINFO_IBSS) ? "ibss" : "????", fail & MATCH_CAPINFO ? '!' : ' '); printf(" %3s%c ", (se->se_capinfo & IEEE80211_CAPINFO_PRIVACY) ? "wep" : "no", fail & MATCH_PRIVACY ? '!' : ' '); ieee80211_print_essid(se->se_ssid+2, se->se_ssid[1]); printf("%s\n", fail & MATCH_SSID ? "!" : ""); } #endif return fail; } static void sta_update_notseen(struct sta_table *st) { struct sta_entry *se; mtx_lock(&st->st_lock); TAILQ_FOREACH(se, &st->st_entry, se_list) { /* * If seen the reset and don't bump the count; * otherwise bump the ``not seen'' count. Note * that this insures that stations for which we * see frames while not scanning but not during * this scan will not be penalized. */ if (se->se_seen) se->se_seen = 0; else se->se_notseen++; } mtx_unlock(&st->st_lock); } static void sta_dec_fails(struct sta_table *st) { struct sta_entry *se; mtx_lock(&st->st_lock); TAILQ_FOREACH(se, &st->st_entry, se_list) if (se->se_fails) se->se_fails--; mtx_unlock(&st->st_lock); } static struct sta_entry * select_bss(struct ieee80211_scan_state *ss, struct ieee80211com *ic, int debug) { struct sta_table *st = ss->ss_priv; struct sta_entry *se, *selbs = NULL; IEEE80211_DPRINTF(ic, debug, " %s\n", "macaddr bssid chan rssi rate flag wep essid"); mtx_lock(&st->st_lock); TAILQ_FOREACH(se, &st->st_entry, se_list) { if (match_bss(ic, ss, se, debug) == 0) { if (selbs == NULL) selbs = se; else if (sta_compare(se, selbs) > 0) selbs = se; } } mtx_unlock(&st->st_lock); return selbs; } /* * Pick an ap or ibss network to join or find a channel * to use to start an ibss network. */ static int sta_pick_bss(struct ieee80211_scan_state *ss, struct ieee80211com *ic) { struct sta_table *st = ss->ss_priv; struct sta_entry *selbs; KASSERT(ic->ic_opmode == IEEE80211_M_STA, ("wrong mode %u", ic->ic_opmode)); if (st->st_newscan) { sta_update_notseen(st); st->st_newscan = 0; } if (ss->ss_flags & IEEE80211_SCAN_NOPICK) { /* * Manual/background scan, don't select+join the * bss, just return. The scanning framework will * handle notification that this has completed. */ ss->ss_flags &= ~IEEE80211_SCAN_NOPICK; return 1; } /* * Automatic sequencing; look for a candidate and * if found join the network. */ /* NB: unlocked read should be ok */ if (TAILQ_FIRST(&st->st_entry) == NULL) { IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN, "%s: no scan candidate\n", __func__); notfound: /* * If nothing suitable was found decrement * the failure counts so entries will be * reconsidered the next time around. We * really want to do this only for sta's * where we've previously had some success. */ sta_dec_fails(st); st->st_newscan = 1; return 0; /* restart scan */ } selbs = select_bss(ss, ic, IEEE80211_MSG_SCAN); if (selbs == NULL || !ieee80211_sta_join(ic, &selbs->base)) goto notfound; return 1; /* terminate scan */ } /* * Lookup an entry in the scan cache. We assume we're * called from the bottom half or such that we don't need * to block the bottom half so that it's safe to return * a reference to an entry w/o holding the lock on the table. */ static struct sta_entry * sta_lookup(struct sta_table *st, const uint8_t macaddr[IEEE80211_ADDR_LEN]) { struct sta_entry *se; int hash = STA_HASH(macaddr); mtx_lock(&st->st_lock); LIST_FOREACH(se, &st->st_hash[hash], se_hash) if (IEEE80211_ADDR_EQ(se->base.se_macaddr, macaddr)) break; mtx_unlock(&st->st_lock); return se; /* NB: unlocked */ } static void sta_roam_check(struct ieee80211_scan_state *ss, struct ieee80211com *ic) { struct ieee80211_node *ni = ic->ic_bss; struct sta_table *st = ss->ss_priv; struct sta_entry *se, *selbs; uint8_t roamRate, curRate; int8_t roamRssi, curRssi; se = sta_lookup(st, ni->ni_macaddr); if (se == NULL) { /* XXX something is wrong */ return; } /* XXX do we need 11g too? */ if (IEEE80211_IS_CHAN_ANYG(ic->ic_bsschan)) { roamRate = ic->ic_roam.rate11b; roamRssi = ic->ic_roam.rssi11b; } else if (IEEE80211_IS_CHAN_B(ic->ic_bsschan)) { roamRate = ic->ic_roam.rate11bOnly; roamRssi = ic->ic_roam.rssi11bOnly; } else { roamRate = ic->ic_roam.rate11a; roamRssi = ic->ic_roam.rssi11a; } /* NB: the most up to date rssi is in the node, not the scan cache */ curRssi = ic->ic_node_getrssi(ni); if (ic->ic_fixed_rate == IEEE80211_FIXED_RATE_NONE) { curRate = ni->ni_rates.rs_rates[ni->ni_txrate] & IEEE80211_RATE_VAL; IEEE80211_DPRINTF(ic, IEEE80211_MSG_ROAM, "%s: currssi %d currate %u roamrssi %d roamrate %u\n", __func__, curRssi, curRate, roamRssi, roamRate); } else { curRate = roamRate; /* NB: insure compare below fails */ IEEE80211_DPRINTF(ic, IEEE80211_MSG_ROAM, "%s: currssi %d roamrssi %d\n", __func__, curRssi, roamRssi); } /* * Check if a new ap should be used and switch. * XXX deauth current ap */ if (curRate < roamRate || curRssi < roamRssi) { if (time_after(ticks, ic->ic_lastscan + ic->ic_scanvalid)) { /* * Scan cache contents are too old; force a scan now * if possible so we have current state to make a * decision with. We don't kick off a bg scan if * we're using dynamic turbo and boosted or if the * channel is busy. * XXX force immediate switch on scan complete */ if (!IEEE80211_IS_CHAN_DTURBO(ic->ic_curchan) && time_after(ticks, ic->ic_lastdata + ic->ic_bgscanidle)) ieee80211_bg_scan(ic); return; } se->base.se_rssi = curRssi; selbs = select_bss(ss, ic, IEEE80211_MSG_ROAM); if (selbs != NULL && selbs != se) { IEEE80211_DPRINTF(ic, IEEE80211_MSG_ROAM | IEEE80211_MSG_DEBUG, "%s: ROAM: curRate %u, roamRate %u, " "curRssi %d, roamRssi %d\n", __func__, curRate, roamRate, curRssi, roamRssi); ieee80211_sta_join(ic, &selbs->base); } } } /* * Age entries in the scan cache. * XXX also do roaming since it's convenient */ static void sta_age(struct ieee80211_scan_state *ss) { struct ieee80211com *ic = ss->ss_ic; struct sta_table *st = ss->ss_priv; struct sta_entry *se, *next; mtx_lock(&st->st_lock); TAILQ_FOREACH_SAFE(se, &st->st_entry, se_list, next) { if (se->se_notseen > STA_PURGE_SCANS) { TAILQ_REMOVE(&st->st_entry, se, se_list); LIST_REMOVE(se, se_hash); FREE(se, M_80211_SCAN); } } mtx_unlock(&st->st_lock); /* * If rate control is enabled check periodically to see if * we should roam from our current connection to one that * might be better. This only applies when we're operating * in sta mode and automatic roaming is set. * XXX defer if busy * XXX repeater station * XXX do when !bgscan? */ KASSERT(ic->ic_opmode == IEEE80211_M_STA, ("wrong mode %u", ic->ic_opmode)); if (ic->ic_roaming == IEEE80211_ROAMING_AUTO && (ic->ic_flags & IEEE80211_F_BGSCAN) && ic->ic_state >= IEEE80211_S_RUN) /* XXX vap is implicit */ sta_roam_check(ss, ic); } /* * Iterate over the entries in the scan cache, invoking * the callback function on each one. */ static void sta_iterate(struct ieee80211_scan_state *ss, ieee80211_scan_iter_func *f, void *arg) { struct sta_table *st = ss->ss_priv; struct sta_entry *se; u_int gen; mtx_lock(&st->st_scanlock); gen = st->st_scangen++; restart: mtx_lock(&st->st_lock); TAILQ_FOREACH(se, &st->st_entry, se_list) { if (se->se_scangen != gen) { se->se_scangen = gen; /* update public state */ se->base.se_age = ticks - se->se_lastupdate; mtx_unlock(&st->st_lock); (*f)(arg, &se->base); goto restart; } } mtx_unlock(&st->st_lock); mtx_unlock(&st->st_scanlock); } static void sta_assoc_fail(struct ieee80211_scan_state *ss, const uint8_t macaddr[IEEE80211_ADDR_LEN], int reason) { struct sta_table *st = ss->ss_priv; struct sta_entry *se; se = sta_lookup(st, macaddr); if (se != NULL) { se->se_fails++; se->se_lastfail = ticks; IEEE80211_NOTE_MAC(ss->ss_ic, IEEE80211_MSG_SCAN, macaddr, "%s: reason %u fails %u", __func__, reason, se->se_fails); } } static void sta_assoc_success(struct ieee80211_scan_state *ss, const uint8_t macaddr[IEEE80211_ADDR_LEN]) { struct sta_table *st = ss->ss_priv; struct sta_entry *se; se = sta_lookup(st, macaddr); if (se != NULL) { #if 0 se->se_fails = 0; IEEE80211_NOTE_MAC(ss->ss_ic, IEEE80211_MSG_SCAN, macaddr, "%s: fails %u", __func__, se->se_fails); #endif se->se_lastassoc = ticks; } } static const struct ieee80211_scanner sta_default = { .scan_name = "default", .scan_attach = sta_attach, .scan_detach = sta_detach, .scan_start = sta_start, .scan_restart = sta_restart, .scan_cancel = sta_cancel, .scan_end = sta_pick_bss, .scan_flush = sta_flush, .scan_add = sta_add, .scan_age = sta_age, .scan_iterate = sta_iterate, .scan_assoc_fail = sta_assoc_fail, .scan_assoc_success = sta_assoc_success, }; /* * Adhoc mode-specific support. */ static const uint16_t adhocWorld[] = /* 36, 40, 44, 48 */ { 5180, 5200, 5220, 5240 }; static const uint16_t adhocFcc3[] = /* 36, 40, 44, 48 145, 149, 153, 157, 161, 165 */ { 5180, 5200, 5220, 5240, 5725, 5745, 5765, 5785, 5805, 5825 }; static const uint16_t adhocMkk[] = /* 34, 38, 42, 46 */ { 5170, 5190, 5210, 5230 }; static const uint16_t adhoc11b[] = /* 10, 11 */ { 2457, 2462 }; static const struct scanlist adhocScanTable[] = { { IEEE80211_MODE_11B, X(adhoc11b) }, { IEEE80211_MODE_11A, X(adhocWorld) }, { IEEE80211_MODE_11A, X(adhocFcc3) }, { IEEE80211_MODE_11B, X(adhocMkk) }, { .list = NULL } }; #undef X /* * Start an adhoc-mode scan by populating the channel list. */ static int adhoc_start(struct ieee80211_scan_state *ss, struct ieee80211com *ic) { #define N(a) (sizeof(a)/sizeof(a[0])) struct sta_table *st = ss->ss_priv; const struct scanlist *scan; enum ieee80211_phymode mode; ss->ss_last = 0; /* * Use the table of ordered channels to construct the list * of channels for scanning. Any channels in the ordered * list not in the master list will be discarded. */ for (scan = adhocScanTable; scan->list != NULL; scan++) { mode = scan->mode; if (ic->ic_des_mode != IEEE80211_MODE_AUTO) { /* * If a desired mode was specified, scan only * channels that satisfy that constraint. */ if (ic->ic_des_mode != mode) { /* * The scan table marks 2.4Ghz channels as b * so if the desired mode is 11g, then use * the 11b channel list but upgrade the mode. */ if (ic->ic_des_mode != IEEE80211_MODE_11G || mode != IEEE80211_MODE_11B) continue; mode = IEEE80211_MODE_11G; /* upgrade */ } } else { /* * This lets add_channels upgrade an 11b channel * to 11g if available. */ if (mode == IEEE80211_MODE_11B) mode = IEEE80211_MODE_AUTO; } #ifdef IEEE80211_F_XR /* XR does not operate on turbo channels */ if ((ic->ic_flags & IEEE80211_F_XR) && (mode == IEEE80211_MODE_TURBO_A || mode == IEEE80211_MODE_TURBO_G)) continue; #endif /* * Add the list of the channels; any that are not * in the master channel list will be discarded. */ add_channels(ic, ss, mode, scan->list, scan->count); } /* * Add the channels from the ic (from HAL) that are not present * in the staScanTable. */ sweepchannels(ss, ic, adhocScanTable); ss->ss_next = 0; /* XXX tunables */ ss->ss_mindwell = msecs_to_ticks(200); /* 200ms */ ss->ss_maxdwell = msecs_to_ticks(200); /* 200ms */ #ifdef IEEE80211_DEBUG if (ieee80211_msg_scan(ic)) { if_printf(ic->ic_ifp, "scan set "); ieee80211_scan_dump_channels(ss); printf(" dwell min %ld max %ld\n", ss->ss_mindwell, ss->ss_maxdwell); } #endif /* IEEE80211_DEBUG */ st->st_newscan = 1; return 0; #undef N } /* * Select a channel to start an adhoc network on. * The channel list was populated with appropriate * channels so select one that looks least occupied. * XXX need regulatory domain constraints */ static struct ieee80211_channel * adhoc_pick_channel(struct ieee80211_scan_state *ss) { struct sta_table *st = ss->ss_priv; struct sta_entry *se; struct ieee80211_channel *c, *bestchan; int i, bestrssi, maxrssi; bestchan = NULL; bestrssi = -1; mtx_lock(&st->st_lock); for (i = 0; i < ss->ss_last; i++) { c = ss->ss_chans[i]; if (!checktable(adhocScanTable, c)) continue; maxrssi = 0; TAILQ_FOREACH(se, &st->st_entry, se_list) { if (se->base.se_chan != c) continue; if (se->base.se_rssi > maxrssi) maxrssi = se->base.se_rssi; } if (bestchan == NULL || maxrssi < bestrssi) bestchan = c; } mtx_unlock(&st->st_lock); return bestchan; } /* * Pick an ibss network to join or find a channel * to use to start an ibss network. */ static int adhoc_pick_bss(struct ieee80211_scan_state *ss, struct ieee80211com *ic) { struct sta_table *st = ss->ss_priv; struct sta_entry *selbs; struct ieee80211_channel *chan; KASSERT(ic->ic_opmode == IEEE80211_M_IBSS || ic->ic_opmode == IEEE80211_M_AHDEMO, ("wrong opmode %u", ic->ic_opmode)); if (st->st_newscan) { sta_update_notseen(st); st->st_newscan = 0; } if (ss->ss_flags & IEEE80211_SCAN_NOPICK) { /* * Manual/background scan, don't select+join the * bss, just return. The scanning framework will * handle notification that this has completed. */ ss->ss_flags &= ~IEEE80211_SCAN_NOPICK; return 1; } /* * Automatic sequencing; look for a candidate and * if found join the network. */ /* NB: unlocked read should be ok */ if (TAILQ_FIRST(&st->st_entry) == NULL) { IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN, "%s: no scan candidate\n", __func__); notfound: if (ic->ic_des_nssid) { /* * No existing adhoc network to join and we have * an ssid; start one up. If no channel was * specified, try to select a channel. */ if (ic->ic_des_chan == IEEE80211_CHAN_ANYC) chan = ieee80211_ht_adjust_channel(ic, adhoc_pick_channel(ss), ic->ic_flags_ext); else chan = ic->ic_des_chan; if (chan != NULL) { ieee80211_create_ibss(ic, chan); return 1; } } /* * If nothing suitable was found decrement * the failure counts so entries will be * reconsidered the next time around. We * really want to do this only for sta's * where we've previously had some success. */ sta_dec_fails(st); st->st_newscan = 1; return 0; /* restart scan */ } selbs = select_bss(ss, ic, IEEE80211_MSG_SCAN); if (selbs == NULL || !ieee80211_sta_join(ic, &selbs->base)) goto notfound; return 1; /* terminate scan */ } /* * Age entries in the scan cache. */ static void adhoc_age(struct ieee80211_scan_state *ss) { struct sta_table *st = ss->ss_priv; struct sta_entry *se, *next; mtx_lock(&st->st_lock); TAILQ_FOREACH_SAFE(se, &st->st_entry, se_list, next) { if (se->se_notseen > STA_PURGE_SCANS) { TAILQ_REMOVE(&st->st_entry, se, se_list); LIST_REMOVE(se, se_hash); FREE(se, M_80211_SCAN); } } mtx_unlock(&st->st_lock); } static const struct ieee80211_scanner adhoc_default = { .scan_name = "default", .scan_attach = sta_attach, .scan_detach = sta_detach, .scan_start = adhoc_start, .scan_restart = sta_restart, .scan_cancel = sta_cancel, .scan_end = adhoc_pick_bss, .scan_flush = sta_flush, .scan_add = sta_add, .scan_age = adhoc_age, .scan_iterate = sta_iterate, .scan_assoc_fail = sta_assoc_fail, .scan_assoc_success = sta_assoc_success, }; /* * Module glue. */ static int wlan_modevent(module_t mod, int type, void *unused) { switch (type) { case MOD_LOAD: ieee80211_scanner_register(IEEE80211_M_STA, &sta_default); ieee80211_scanner_register(IEEE80211_M_IBSS, &adhoc_default); ieee80211_scanner_register(IEEE80211_M_AHDEMO, &adhoc_default); return 0; case MOD_UNLOAD: case MOD_QUIESCE: if (nrefs) { printf("wlan_scan_sta: still in use (%u dynamic refs)\n", nrefs); return EBUSY; } if (type == MOD_UNLOAD) { ieee80211_scanner_unregister_all(&sta_default); ieee80211_scanner_unregister_all(&adhoc_default); } return 0; } return EINVAL; } static moduledata_t wlan_mod = { "wlan_scan_sta", wlan_modevent, 0 }; DECLARE_MODULE(wlan_scan_sta, wlan_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST); MODULE_VERSION(wlan_scan_sta, 1); MODULE_DEPEND(wlan_scan_sta, wlan, 1, 1, 1);