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Diffstat (limited to 'sys/net80211/ieee80211_scan.c')
| -rw-r--r-- | sys/net80211/ieee80211_scan.c | 990 |
1 files changed, 990 insertions, 0 deletions
diff --git a/sys/net80211/ieee80211_scan.c b/sys/net80211/ieee80211_scan.c new file mode 100644 index 0000000..6099744 --- /dev/null +++ b/sys/net80211/ieee80211_scan.c @@ -0,0 +1,990 @@ +/*- + * 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 <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +/* + * IEEE 802.11 scanning support. + */ +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/kernel.h> + +#include <sys/socket.h> + +#include <net/if.h> +#include <net/if_media.h> +#include <net/ethernet.h> + +#include <net80211/ieee80211_var.h> + +#include <net/bpf.h> + +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). + */ +#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 */ + +static void scan_restart_pwrsav(void *); +static void scan_curchan(struct ieee80211com *, unsigned long); +static void scan_mindwell(struct ieee80211com *); +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; + + ic->ic_roaming = IEEE80211_ROAMING_AUTO; + + 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(&ss->ss_scan_timer, CALLOUT_MPSAFE); + ic->ic_scan = &ss->base; + + ic->ic_scan_curchan = scan_curchan; + ic->ic_scan_mindwell = scan_mindwell; + + ic->ic_bgscanidle = (IEEE80211_BGSCAN_IDLE_DEFAULT*1000)/hz; + ic->ic_bgscanintvl = IEEE80211_BGSCAN_INTVAL_DEFAULT*hz; + ic->ic_scanvalid = IEEE80211_SCAN_VALID_DEFAULT*hz; + ic->ic_roam.rssi11a = ROAM_RSSI_11A_DEFAULT; + ic->ic_roam.rssi11b = ROAM_RSSI_11B_DEFAULT; + ic->ic_roam.rssi11bOnly = ROAM_RSSI_11BONLY_DEFAULT; + ic->ic_roam.rate11a = ROAM_RATE_11A_DEFAULT; + ic->ic_roam.rate11b = ROAM_RATE_11B_DEFAULT; + ic->ic_roam.rate11bOnly = ROAM_RATE_11BONLY_DEFAULT; +} + +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); + } +} + +/* + * Simple-minded scanner module support. + */ +#define IEEE80211_SCANNER_MAX (IEEE80211_M_MONITOR+1) + +static const char *scan_modnames[IEEE80211_SCANNER_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_4", /* n/a */ + "wlan_scan_5", /* n/a */ + "wlan_scan_ap", /* IEEE80211_M_HOSTAP */ + "wlan_scan_7", /* n/a */ + "wlan_scan_monitor", /* IEEE80211_M_MONITOR */ +}; +static const struct ieee80211_scanner *scanners[IEEE80211_SCANNER_MAX]; + +const struct ieee80211_scanner * +ieee80211_scanner_get(enum ieee80211_opmode mode) +{ + if (mode >= IEEE80211_SCANNER_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_SCANNER_MAX) + return; + scanners[mode] = scan; +} + +void +ieee80211_scanner_unregister(enum ieee80211_opmode mode, + const struct ieee80211_scanner *scan) +{ + if (mode >= IEEE80211_SCANNER_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_SCANNER_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. + */ +int +ieee80211_scan_update(struct ieee80211com *ic) +{ + struct ieee80211_scan_state *ss = ic->ic_scan; + const struct ieee80211_scanner *scan; + + scan = ieee80211_scanner_get(ic->ic_opmode); + IEEE80211_LOCK(ic); + if (scan == NULL) { + IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN, + "%s: no scanner support for mode %u\n", + __func__, ic->ic_opmode); + /* XXX stat */ + } + ss->ss_ic = ic; + if (ss->ss_ops != scan) { + /* switch scanners; detach old, attach new */ + if (ss->ss_ops != NULL) + ss->ss_ops->scan_detach(ss); + if (scan != NULL && !scan->scan_attach(ss)) { + /* XXX attach failure */ + /* XXX stat+msg */ + ss->ss_ops = NULL; + } else + ss->ss_ops = scan; + } + IEEE80211_UNLOCK(ic); + + return (scan != NULL); +} + +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_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 = ", "; + } +} + +/* + * 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 ieee80211com *ic = ss->base.ss_ic; + int delay; + + ieee80211_sta_pwrsave(ic, 1); + /* + * Use an initial 1ms delay to insure the null + * data frame has a chance to go out. + * XXX 1ms is a lot, better to trigger scan + * on tx complete. + */ + delay = hz/1000; + if (delay < 1) + delay = 1; + ic->ic_scan_start(ic); /* notify driver */ + ss->ss_scanend = ticks + delay + ss->ss_duration; + ss->ss_iflags |= ISCAN_START; + callout_reset(&ss->ss_scan_timer, delay, 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 ieee80211com *ic = ss->base.ss_ic; + int defer = 0; + + if (ss->base.ss_next == ss->base.ss_last) { + IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN, + "%s: no channels to scan\n", __func__); + return 0; + } + if (ic->ic_opmode == IEEE80211_M_STA && + ic->ic_state == IEEE80211_S_RUN) { + if ((ic->ic_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 ieee80211com *ic, struct ieee80211_scan_state *ss, + int nssid, const struct ieee80211_scan_ssid ssids[]) +{ + if (nssid > IEEE80211_SCAN_MAX_SSID) { + /* XXX printf */ + IEEE80211_DPRINTF(ic, 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. + */ +int +ieee80211_start_scan(struct ieee80211com *ic, int flags, u_int duration, + u_int nssid, const struct ieee80211_scan_ssid ssids[]) +{ + const struct ieee80211_scanner *scan; + struct ieee80211_scan_state *ss = ic->ic_scan; + + scan = ieee80211_scanner_get(ic->ic_opmode); + if (scan == NULL) { + IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN, + "%s: no scanner support for mode %u\n", + __func__, ic->ic_opmode); + /* XXX stat */ + return 0; + } + + IEEE80211_LOCK(ic); + if ((ic->ic_flags & IEEE80211_F_SCAN) == 0) { + IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN, + "%s: %s scan, duration %u, desired mode %s, %s%s%s%s\n" + , __func__ + , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive" + , duration + , ieee80211_phymode_name[ic->ic_des_mode] + , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append" + , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : "" + , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : "" + , flags & IEEE80211_SCAN_ONCE ? ", once" : "" + ); + + ss->ss_ic = ic; + if (ss->ss_ops != scan) { + /* switch scanners; detach old, attach new */ + if (ss->ss_ops != NULL) + ss->ss_ops->scan_detach(ss); + if (!scan->scan_attach(ss)) { + /* XXX attach failure */ + /* XXX stat+msg */ + ss->ss_ops = NULL; + } else + ss->ss_ops = scan; + } + if (ss->ss_ops != NULL) { + if ((flags & IEEE80211_SCAN_NOSSID) == 0) + copy_ssid(ic, ss, nssid, ssids); + + /* NB: top 4 bits for internal use */ + ss->ss_flags = flags & 0xfff; + if (ss->ss_flags & IEEE80211_SCAN_ACTIVE) + ic->ic_stats.is_scan_active++; + else + ic->ic_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_ops->scan_start(ss, ic); + if (scan_restart(SCAN_PRIVATE(ss), duration)) + ic->ic_flags |= IEEE80211_F_SCAN; + } + } else { + IEEE80211_DPRINTF(ic, 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); +} + +/* + * Check the scan cache for an ap/channel to use; if that + * fails then kick off a new scan. + */ +int +ieee80211_check_scan(struct ieee80211com *ic, int flags, u_int duration, + u_int nssid, const struct ieee80211_scan_ssid ssids[]) +{ + struct ieee80211_scan_state *ss = ic->ic_scan; + int checkscanlist = 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(ic, IEEE80211_MSG_SCAN, + "%s: %s scan, duration %u, desired mode %s, %s%s%s%s\n" + , __func__ + , flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive" + , duration + , ieee80211_phymode_name[ic->ic_des_mode] + , flags & IEEE80211_SCAN_FLUSH ? "flush" : "append" + , flags & IEEE80211_SCAN_NOPICK ? ", nopick" : "" + , flags & IEEE80211_SCAN_PICK1ST ? ", pick1st" : "" + , flags & IEEE80211_SCAN_ONCE ? ", once" : "" + ); + + if (ss->ss_ops != NULL) { + /* XXX verify ss_ops matches ic->ic_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(ic, ss, nssid, ssids); + flags |= IEEE80211_SCAN_NOSSID; + } + if ((ic->ic_flags & IEEE80211_F_SCAN) == 0 && + time_before(ticks, ic->ic_lastscan + ic->ic_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; + checkscanlist = 1; + } + } + IEEE80211_UNLOCK(ic); + if (checkscanlist) { + const struct ieee80211_scanner *scan; + + scan = ieee80211_scanner_get(ic->ic_opmode); + if (scan == NULL) { + IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN, + "%s: no scanner support for mode %u\n", + __func__, ic->ic_opmode); + /* XXX stat */ + return 0; + } + if (scan == ss->ss_ops && ss->ss_ops->scan_end(ss, ic)) { + /* found an ap, just clear the flag */ + ic->ic_flags &= ~IEEE80211_F_SCAN; + return 1; + } + /* no ap, clear the flag before starting a scan */ + ic->ic_flags &= ~IEEE80211_F_SCAN; + } + return ieee80211_start_scan(ic, flags, duration, nssid, ssids); +} + +/* + * Restart a previous scan. If the previous scan completed + * then we start again using the existing channel list. + */ +int +ieee80211_bg_scan(struct ieee80211com *ic) +{ + struct ieee80211_scan_state *ss = ic->ic_scan; + + 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(ic, IEEE80211_MSG_SCAN, + "%s: %s scan, ticks %u duration %lu\n", __func__, + ss->ss_flags & IEEE80211_SCAN_ACTIVE ? "active" : "passive", + ticks, duration); + + if (ss->ss_ops != NULL) { + ss->ss_ic = ic; + /* + * 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; + /* if previous scan completed, restart */ + if (ss->ss_next >= ss->ss_last) { + ss->ss_next = 0; + if (ss->ss_flags & IEEE80211_SCAN_ACTIVE) + ic->ic_stats.is_scan_active++; + else + ic->ic_stats.is_scan_passive++; + ss->ss_ops->scan_restart(ss, ic); + } + /* 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(ic, 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. + */ +void +ieee80211_cancel_scan(struct ieee80211com *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(ic, 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 ieee80211com *ic) +{ + /* + * XXX: We might need/want to decouple context here by either: + * callout_reset(&SCAN_PRIVATE(ss)->ss_scan_timer, 0, scan_next, ss); + * or using a taskqueue. Let's see what kind of problems direct + * dispatch has for now. + */ + scan_next(ic->ic_scan); +} + +/* + * 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 ieee80211com *ic, unsigned long maxdwell) +{ + struct ieee80211_scan_state *ss = ic->ic_scan; + + if ((ss->ss_flags & IEEE80211_SCAN_ACTIVE) && + (ic->ic_curchan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0) { + struct ifnet *ifp = ic->ic_ifp; + int i; + + /* + * Send a broadcast probe request followed by + * any specified directed probe requests. + * XXX suppress broadcast probe req? + * XXX remove dependence on ic/ic->ic_bss + * XXX move to policy code? + */ + ieee80211_send_probereq(ic->ic_bss, + ic->ic_myaddr, ifp->if_broadcastaddr, + ifp->if_broadcastaddr, + "", 0, + ic->ic_opt_ie, ic->ic_opt_ie_len); + for (i = 0; i < ss->ss_nssid; i++) + ieee80211_send_probereq(ic->ic_bss, + ic->ic_myaddr, ifp->if_broadcastaddr, + ifp->if_broadcastaddr, + ss->ss_ssid[i].ssid, + ss->ss_ssid[i].len, + ic->ic_opt_ie, ic->ic_opt_ie_len); + } + 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 ieee80211com *ic) +{ + struct ieee80211_scan_state *ss = ic->ic_scan; + + 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 ieee80211com *ic = ss->ss_ic; + struct ieee80211_channel *chan; + unsigned long maxdwell, scanend; + int scanning, scandone; + + IEEE80211_LOCK(ic); + scanning = (ic->ic_flags & IEEE80211_F_SCAN) != 0; + IEEE80211_UNLOCK(ic); + if (!scanning) /* canceled */ + 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(ic, 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(ic, 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) + change_channel(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, ic) && + (ss->ss_flags & IEEE80211_SCAN_ONCE) == 0 && + time_before(ticks + ss->ss_mindwell, scanend)) { + IEEE80211_DPRINTF(ic, 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) + ic->ic_stats.is_scan_active++; + else + ic->ic_stats.is_scan_passive++; + + 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(ic, 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(ic, 0); + if (ss->ss_next >= ss->ss_last) { + ieee80211_notify_scan_done(ic); + 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_probe_beacon(uint8_t subtype, int isnew, + const uint8_t mac[IEEE80211_ADDR_LEN], + const struct ieee80211_scanparams *sp) +{ + + 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("\n"); + + 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) { +#ifdef __FreeBSD__ + printf(" country info %*D", + sp->country[1], sp->country+2, " "); +#else + int i; + printf(" country info"); + for (i = 0; i < sp->country[1]; i++) + printf(" %02x", sp->country[i+2]); +#endif + } + printf("\n"); + } +} +#endif /* IEEE80211_DEBUG */ + +/* + * Process a beacon or probe response frame. + */ +void +ieee80211_add_scan(struct ieee80211com *ic, + const struct ieee80211_scanparams *sp, + const struct ieee80211_frame *wh, + int subtype, int rssi, int noise, int rstamp) +{ + struct ieee80211_scan_state *ss = ic->ic_scan; + + /* + * 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 (we defer the channel change to the timer + * code to simplify locking on linux). + */ + if (SCAN_PRIVATE(ss)->ss_iflags & ISCAN_DISCARD) + return; +#ifdef IEEE80211_DEBUG + if (ieee80211_msg_scan(ic) && (ic->ic_flags & IEEE80211_F_SCAN)) + dump_probe_beacon(subtype, 1, wh->i_addr2, sp); +#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(ic, 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); + /* + * XXX + * We want to just kick the timer and still + * process frames until it fires but linux + * will livelock unless we discard frames. + */ +#if 0 + SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_MINDWELL; +#else + SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_DISCARD; +#endif + /* + * NB: trigger at next clock tick or wait for the + * hardware + */ + ic->ic_scan_mindwell(ic); + } + } +} + +/* + * 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 ieee80211com *ic, const uint8_t mac[]) +{ + struct ieee80211_scan_state *ss = ic->ic_scan; + + if (ss->ss_ops != NULL) { + IEEE80211_NOTE_MAC(ic, 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 ieee80211com *ic, + const uint8_t mac[], int reason) +{ + struct ieee80211_scan_state *ss = ic->ic_scan; + + if (ss->ss_ops != NULL) { + IEEE80211_NOTE_MAC(ic, 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 ieee80211com *ic, + ieee80211_scan_iter_func *f, void *arg) +{ + struct ieee80211_scan_state *ss = 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 ieee80211com *ic) +{ + struct ieee80211_scan_state *ss = ic->ic_scan; + + if (ss->ss_ops != NULL) { + IEEE80211_DPRINTF(ic, IEEE80211_MSG_SCAN, + "%s\n", __func__); + ss->ss_ops->scan_flush(ss); + } +} |
