net/ieee80211/softmac/ieee80211softmac_scan.c

   1 /*
   2  * Scanning routines.
   3  *
   4  * These are not exported because they're assigned to the function pointers.
   5  *
   6  * Copyright (c) 2005, 2006 Johannes Berg <johannes@sipsolutions.net>
   7  *                          Joseph Jezak <josejx@gentoo.org>
   8  *                          Larry Finger <Larry.Finger@lwfinger.net>
   9  *                          Danny van Dyk <kugelfang@gentoo.org>
  10  *                          Michael Buesch <mbuesch@freenet.de>
  11  *
  12  * This program is free software; you can redistribute it and/or modify it
  13  * under the terms of version 2 of the GNU General Public License as
  14  * published by the Free Software Foundation.
  15  *
  16  * This program is distributed in the hope that it will be useful, but WITHOUT
  17  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  18  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  19  * more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  24  *
  25  * The full GNU General Public License is included in this distribution in the
  26  * file called COPYING.
  27  */
  28
  29 #include <linux/completion.h>
  30 #include "ieee80211softmac_priv.h"
  31
  32 /* internal, use to trigger scanning if needed.
  33  * Returns -EBUSY if already scanning,
  34  * result of start_scan otherwise */
  35 int
  36 ieee80211softmac_start_scan(struct ieee80211softmac_device *sm)
  37 {
  38         unsigned long flags;
  39         int ret;
  40
  41         spin_lock_irqsave(&sm->lock, flags);
  42         if (sm->scanning)
  43         {
  44                 spin_unlock_irqrestore(&sm->lock, flags);
  45                 return -EINPROGRESS;
  46         }
  47         sm->scanning = 1;
  48         spin_unlock_irqrestore(&sm->lock, flags);
  49
  50         netif_tx_disable(sm->ieee->dev);
  51         ret = sm->start_scan(sm->dev);
  52         if (ret) {
  53                 spin_lock_irqsave(&sm->lock, flags);
  54                 sm->scanning = 0;
  55                 spin_unlock_irqrestore(&sm->lock, flags);
  56         }
  57         return ret;
  58 }
  59
  60 void
  61 ieee80211softmac_stop_scan(struct ieee80211softmac_device *sm)
  62 {
  63         unsigned long flags;
  64
  65         spin_lock_irqsave(&sm->lock, flags);
  66
  67         if (!sm->scanning) {
  68                 spin_unlock_irqrestore(&sm->lock, flags);
  69                 return;
  70         }
  71
  72         spin_unlock_irqrestore(&sm->lock, flags);
  73         sm->stop_scan(sm->dev);
  74 }
  75
  76 void
  77 ieee80211softmac_wait_for_scan(struct ieee80211softmac_device *sm)
  78 {
  79         unsigned long flags;
  80
  81         spin_lock_irqsave(&sm->lock, flags);
  82
  83         if (!sm->scanning) {
  84                 spin_unlock_irqrestore(&sm->lock, flags);
  85                 return;
  86         }
  87
  88         spin_unlock_irqrestore(&sm->lock, flags);
  89         sm->wait_for_scan(sm->dev);
  90 }
  91
  92
  93 /* internal scanning implementation follows */
  94 void ieee80211softmac_scan(void *d)
  95 {
  96         int invalid_channel;
  97         u8 current_channel_idx;
  98         struct ieee80211softmac_device *sm = (struct ieee80211softmac_device *)d;
  99         struct ieee80211softmac_scaninfo *si = sm->scaninfo;
 100         unsigned long flags;
 101
 102         while (!(si->stop) && (si->current_channel_idx < si->number_channels)) {
 103                 current_channel_idx = si->current_channel_idx;
 104                 si->current_channel_idx++; /* go to the next channel */
 105
 106                 invalid_channel = (si->skip_flags & si->channels[current_channel_idx].flags);
 107
 108                 if (!invalid_channel) {
 109                         sm->set_channel(sm->dev, si->channels[current_channel_idx].channel);
 110                         // FIXME make this user configurable (active/passive)
 111                         if(ieee80211softmac_send_mgt_frame(sm, NULL, IEEE80211_STYPE_PROBE_REQ, 0))
 112                                 printkl(KERN_DEBUG PFX "Sending Probe Request Failed\n");
 113
 114                         /* also send directed management frame for the network we're looking for */
 115                         // TODO: is this if correct, or should we do this only if scanning from assoc request?
 116                         if (sm->associnfo.req_essid.len)
 117                                 ieee80211softmac_send_mgt_frame(sm, &sm->associnfo.req_essid, IEEE80211_STYPE_PROBE_REQ, 0);
 118
 119                         spin_lock_irqsave(&sm->lock, flags);
 120                         if (unlikely(!sm->running)) {
 121                                 /* Prevent reschedule on workqueue flush */
 122                                 spin_unlock_irqrestore(&sm->lock, flags);
 123                                 break;
 124                         }
 125                         schedule_delayed_work(&si->softmac_scan, IEEE80211SOFTMAC_PROBE_DELAY);
 126                         spin_unlock_irqrestore(&sm->lock, flags);
 127                         return;
 128                 } else {
 129                         dprintk(PFX "Not probing Channel %d (not allowed here)\n", si->channels[current_channel_idx].channel);
 130                 }
 131         }
 132
 133         spin_lock_irqsave(&sm->lock, flags);
 134         cancel_delayed_work(&si->softmac_scan);
 135         si->started = 0;
 136         spin_unlock_irqrestore(&sm->lock, flags);
 137
 138         dprintk(PFX "Scanning finished\n");
 139         ieee80211softmac_scan_finished(sm);
 140         complete_all(&sm->scaninfo->finished);
 141 }
 142
 143 static inline struct ieee80211softmac_scaninfo *allocate_scaninfo(struct ieee80211softmac_device *mac)
 144 {
 145         /* ugh. can we call this without having the spinlock held? */
 146         struct ieee80211softmac_scaninfo *info = kmalloc(sizeof(struct ieee80211softmac_scaninfo), GFP_ATOMIC);
 147         if (unlikely(!info))
 148                 return NULL;
 149         INIT_WORK(&info->softmac_scan, ieee80211softmac_scan, mac);
 150         init_completion(&info->finished);
 151         return info;
 152 }
 153
 154 int ieee80211softmac_start_scan_implementation(struct net_device *dev)
 155 {
 156         struct ieee80211softmac_device *sm = ieee80211_priv(dev);
 157         unsigned long flags;
 158
 159         if (!(dev->flags & IFF_UP))
 160                 return -ENODEV;
 161
 162         assert(ieee80211softmac_scan_handlers_check_self(sm));
 163         if (!ieee80211softmac_scan_handlers_check_self(sm))
 164                 return -EINVAL;
 165
 166         spin_lock_irqsave(&sm->lock, flags);
 167         /* it looks like we need to hold the lock here
 168          * to make sure we don't allocate two of these... */
 169         if (unlikely(!sm->scaninfo))
 170                 sm->scaninfo = allocate_scaninfo(sm);
 171         if (unlikely(!sm->scaninfo)) {
 172                 spin_unlock_irqrestore(&sm->lock, flags);
 173                 return -ENOMEM;
 174         }
 175
 176         sm->scaninfo->skip_flags = IEEE80211_CH_INVALID;
 177         if (0 /* not scanning in IEEE802.11b */)//TODO
 178                 sm->scaninfo->skip_flags |= IEEE80211_CH_B_ONLY;
 179         if (0 /* IEEE802.11a */) {//TODO
 180                 sm->scaninfo->channels = sm->ieee->geo.a;
 181                 sm->scaninfo->number_channels = sm->ieee->geo.a_channels;
 182         } else {
 183                 sm->scaninfo->channels = sm->ieee->geo.bg;
 184                 sm->scaninfo->number_channels = sm->ieee->geo.bg_channels;
 185         }
 186         dprintk(PFX "Start scanning with channel: %d\n", sm->scaninfo->channels[0].channel);
 187         dprintk(PFX "Scanning %d channels\n", sm->scaninfo->number_channels);
 188         sm->scaninfo->current_channel_idx = 0;
 189         sm->scaninfo->started = 1;
 190         sm->scaninfo->stop = 0;
 191         INIT_COMPLETION(sm->scaninfo->finished);
 192         schedule_work(&sm->scaninfo->softmac_scan);
 193         spin_unlock_irqrestore(&sm->lock, flags);
 194         return 0;
 195 }
 196
 197 void ieee80211softmac_stop_scan_implementation(struct net_device *dev)
 198 {
 199         struct ieee80211softmac_device *sm = ieee80211_priv(dev);
 200         unsigned long flags;
 201
 202         assert(ieee80211softmac_scan_handlers_check_self(sm));
 203         if (!ieee80211softmac_scan_handlers_check_self(sm))
 204                 return;
 205
 206         spin_lock_irqsave(&sm->lock, flags);
 207         assert(sm->scaninfo != NULL);
 208         if (sm->scaninfo) {
 209                 if (sm->scaninfo->started)
 210                         sm->scaninfo->stop = 1;
 211                 else
 212                         complete_all(&sm->scaninfo->finished);
 213         }
 214         spin_unlock_irqrestore(&sm->lock, flags);
 215 }
 216
 217 void ieee80211softmac_wait_for_scan_implementation(struct net_device *dev)
 218 {
 219         struct ieee80211softmac_device *sm = ieee80211_priv(dev);
 220         unsigned long flags;
 221
 222         assert(ieee80211softmac_scan_handlers_check_self(sm));
 223         if (!ieee80211softmac_scan_handlers_check_self(sm))
 224                 return;
 225
 226         spin_lock_irqsave(&sm->lock, flags);
 227         if (!sm->scaninfo->started) {
 228                 spin_unlock_irqrestore(&sm->lock, flags);
 229                 return;
 230         }
 231         spin_unlock_irqrestore(&sm->lock, flags);
 232         wait_for_completion(&sm->scaninfo->finished);
 233 }
 234
 235 /* this is what drivers (that do scanning) call when they're done */
 236 void ieee80211softmac_scan_finished(struct ieee80211softmac_device *sm)
 237 {
 238         unsigned long flags;
 239
 240         spin_lock_irqsave(&sm->lock, flags);
 241         sm->scanning = 0;
 242         spin_unlock_irqrestore(&sm->lock, flags);
 243
 244         if (sm->associnfo.bssvalid) {
 245                 struct ieee80211softmac_network *net;
 246
 247                 net = ieee80211softmac_get_network_by_bssid(sm, sm->associnfo.bssid);
 248                 if (net)
 249                         sm->set_channel(sm->dev, net->channel);
 250         }
 251         netif_wake_queue(sm->ieee->dev);
 252         ieee80211softmac_call_events(sm, IEEE80211SOFTMAC_EVENT_SCAN_FINISHED, NULL);
 253 }
 254 EXPORT_SYMBOL_GPL(ieee80211softmac_scan_finished);