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         ret = sm->start_scan(sm->dev);
  51         if (ret) {
  52                 spin_lock_irqsave(&sm->lock, flags);
  53                 sm->scanning = 0;
  54                 spin_unlock_irqrestore(&sm->lock, flags);
  55         }
  56         return ret;
  57 }
  58
  59 void
  60 ieee80211softmac_stop_scan(struct ieee80211softmac_device *sm)
  61 {
  62         unsigned long flags;
  63
  64         spin_lock_irqsave(&sm->lock, flags);
  65
  66         if (!sm->scanning) {
  67                 spin_unlock_irqrestore(&sm->lock, flags);
  68                 return;
  69         }
  70
  71         spin_unlock_irqrestore(&sm->lock, flags);
  72         sm->stop_scan(sm->dev);
  73 }
  74
  75 void
  76 ieee80211softmac_wait_for_scan(struct ieee80211softmac_device *sm)
  77 {
  78         unsigned long flags;
  79
  80         spin_lock_irqsave(&sm->lock, flags);
  81
  82         if (!sm->scanning) {
  83                 spin_unlock_irqrestore(&sm->lock, flags);
  84                 return;
  85         }
  86
  87         spin_unlock_irqrestore(&sm->lock, flags);
  88         sm->wait_for_scan(sm->dev);
  89 }
  90
  91
  92 /* internal scanning implementation follows */
  93 void ieee80211softmac_scan(void *d)
  94 {
  95         int invalid_channel;
  96         u8 current_channel_idx;
  97         struct ieee80211softmac_device *sm = (struct ieee80211softmac_device *)d;
  98         struct ieee80211softmac_scaninfo *si = sm->scaninfo;
  99         unsigned long flags;
 100
 101         while (!(si->stop) && (si->current_channel_idx < si->number_channels)) {
 102                 current_channel_idx = si->current_channel_idx;
 103                 si->current_channel_idx++; /* go to the next channel */
 104
 105                 invalid_channel = (si->skip_flags & si->channels[current_channel_idx].flags);
 106
 107                 if (!invalid_channel) {
 108                         sm->set_channel(sm->dev, si->channels[current_channel_idx].channel);
 109                         // FIXME make this user configurable (active/passive)
 110                         if(ieee80211softmac_send_mgt_frame(sm, NULL, IEEE80211_STYPE_PROBE_REQ, 0))
 111                                 printkl(KERN_DEBUG PFX "Sending Probe Request Failed\n");
 112
 113                         /* also send directed management frame for the network we're looking for */
 114                         // TODO: is this if correct, or should we do this only if scanning from assoc request?
 115                         if (sm->associnfo.req_essid.len)
 116                                 ieee80211softmac_send_mgt_frame(sm, &sm->associnfo.req_essid, IEEE80211_STYPE_PROBE_REQ, 0);
 117
 118                         spin_lock_irqsave(&sm->lock, flags);
 119                         if (unlikely(!sm->running)) {
 120                                 /* Prevent reschedule on workqueue flush */
 121                                 spin_unlock_irqrestore(&sm->lock, flags);
 122                                 break;
 123                         }
 124                         schedule_delayed_work(&si->softmac_scan, IEEE80211SOFTMAC_PROBE_DELAY);
 125                         spin_unlock_irqrestore(&sm->lock, flags);
 126                         return;
 127                 } else {
 128                         dprintk(PFX "Not probing Channel %d (not allowed here)\n", si->channels[current_channel_idx].channel);
 129                 }
 130         }
 131
 132         spin_lock_irqsave(&sm->lock, flags);
 133         cancel_delayed_work(&si->softmac_scan);
 134         si->started = 0;
 135         spin_unlock_irqrestore(&sm->lock, flags);
 136
 137         dprintk(PFX "Scanning finished\n");
 138         ieee80211softmac_scan_finished(sm);
 139         complete_all(&sm->scaninfo->finished);
 140 }
 141
 142 static inline struct ieee80211softmac_scaninfo *allocate_scaninfo(struct ieee80211softmac_device *mac)
 143 {
 144         /* ugh. can we call this without having the spinlock held? */
 145         struct ieee80211softmac_scaninfo *info = kmalloc(sizeof(struct ieee80211softmac_scaninfo), GFP_ATOMIC);
 146         if (unlikely(!info))
 147                 return NULL;
 148         INIT_WORK(&info->softmac_scan, ieee80211softmac_scan, mac);
 149         init_completion(&info->finished);
 150         return info;
 151 }
 152
 153 int ieee80211softmac_start_scan_implementation(struct net_device *dev)
 154 {
 155         struct ieee80211softmac_device *sm = ieee80211_priv(dev);
 156         unsigned long flags;
 157
 158         if (!(dev->flags & IFF_UP))
 159                 return -ENODEV;
 160
 161         assert(ieee80211softmac_scan_handlers_check_self(sm));
 162         if (!ieee80211softmac_scan_handlers_check_self(sm))
 163                 return -EINVAL;
 164
 165         spin_lock_irqsave(&sm->lock, flags);
 166         /* it looks like we need to hold the lock here
 167          * to make sure we don't allocate two of these... */
 168         if (unlikely(!sm->scaninfo))
 169                 sm->scaninfo = allocate_scaninfo(sm);
 170         if (unlikely(!sm->scaninfo)) {
 171                 spin_unlock_irqrestore(&sm->lock, flags);
 172                 return -ENOMEM;
 173         }
 174
 175         sm->scaninfo->skip_flags = IEEE80211_CH_INVALID;
 176         if (0 /* not scanning in IEEE802.11b */)//TODO
 177                 sm->scaninfo->skip_flags |= IEEE80211_CH_B_ONLY;
 178         if (0 /* IEEE802.11a */) {//TODO
 179                 sm->scaninfo->channels = sm->ieee->geo.a;
 180                 sm->scaninfo->number_channels = sm->ieee->geo.a_channels;
 181         } else {
 182                 sm->scaninfo->channels = sm->ieee->geo.bg;
 183                 sm->scaninfo->number_channels = sm->ieee->geo.bg_channels;
 184         }
 185         dprintk(PFX "Start scanning with channel: %d\n", sm->scaninfo->channels[0].channel);
 186         dprintk(PFX "Scanning %d channels\n", sm->scaninfo->number_channels);
 187         sm->scaninfo->current_channel_idx = 0;
 188         sm->scaninfo->started = 1;
 189         sm->scaninfo->stop = 0;
 190         INIT_COMPLETION(sm->scaninfo->finished);
 191         schedule_work(&sm->scaninfo->softmac_scan);
 192         spin_unlock_irqrestore(&sm->lock, flags);
 193         return 0;
 194 }
 195
 196 void ieee80211softmac_stop_scan_implementation(struct net_device *dev)
 197 {
 198         struct ieee80211softmac_device *sm = ieee80211_priv(dev);
 199         unsigned long flags;
 200
 201         assert(ieee80211softmac_scan_handlers_check_self(sm));
 202         if (!ieee80211softmac_scan_handlers_check_self(sm))
 203                 return;
 204
 205         spin_lock_irqsave(&sm->lock, flags);
 206         assert(sm->scaninfo != NULL);
 207         if (sm->scaninfo) {
 208                 if (sm->scaninfo->started)
 209                         sm->scaninfo->stop = 1;
 210                 else
 211                         complete_all(&sm->scaninfo->finished);
 212         }
 213         spin_unlock_irqrestore(&sm->lock, flags);
 214 }
 215
 216 void ieee80211softmac_wait_for_scan_implementation(struct net_device *dev)
 217 {
 218         struct ieee80211softmac_device *sm = ieee80211_priv(dev);
 219         unsigned long flags;
 220
 221         assert(ieee80211softmac_scan_handlers_check_self(sm));
 222         if (!ieee80211softmac_scan_handlers_check_self(sm))
 223                 return;
 224
 225         spin_lock_irqsave(&sm->lock, flags);
 226         if (!sm->scaninfo->started) {
 227                 spin_unlock_irqrestore(&sm->lock, flags);
 228                 return;
 229         }
 230         spin_unlock_irqrestore(&sm->lock, flags);
 231         wait_for_completion(&sm->scaninfo->finished);
 232 }
 233
 234 /* this is what drivers (that do scanning) call when they're done */
 235 void ieee80211softmac_scan_finished(struct ieee80211softmac_device *sm)
 236 {
 237         unsigned long flags;
 238
 239         spin_lock_irqsave(&sm->lock, flags);
 240         sm->scanning = 0;
 241         spin_unlock_irqrestore(&sm->lock, flags);
 242
 243         if (sm->associnfo.bssvalid) {
 244                 struct ieee80211softmac_network *net;
 245
 246                 net = ieee80211softmac_get_network_by_bssid(sm, sm->associnfo.bssid);
 247                 if (net)
 248                         sm->set_channel(sm->dev, net->channel);
 249         }
 250         ieee80211softmac_call_events(sm, IEEE80211SOFTMAC_EVENT_SCAN_FINISHED, NULL);
 251 }
 252 EXPORT_SYMBOL_GPL(ieee80211softmac_scan_finished);