net/wireless/chan.c

   1 /*
   2  * This file contains helper code to handle channel
   3  * settings and keeping track of what is possible at
   4  * any point in time.
   5  *
   6  * Copyright 2009       Johannes Berg <johannes@sipsolutions.net>
   7  */
   8
   9 #include <linux/export.h>
  10 #include <net/cfg80211.h>
  11 #include "core.h"
  12
  13 struct ieee80211_channel *
  14 rdev_freq_to_chan(struct cfg80211_registered_device *rdev,
  15                   int freq, enum nl80211_channel_type channel_type)
  16 {
  17         struct ieee80211_channel *chan;
  18         struct ieee80211_sta_ht_cap *ht_cap;
  19
  20         chan = ieee80211_get_channel(&rdev->wiphy, freq);
  21
  22         /* Primary channel not allowed */
  23         if (!chan || chan->flags & IEEE80211_CHAN_DISABLED)
  24                 return NULL;
  25
  26         if (channel_type == NL80211_CHAN_HT40MINUS &&
  27             chan->flags & IEEE80211_CHAN_NO_HT40MINUS)
  28                 return NULL;
  29         else if (channel_type == NL80211_CHAN_HT40PLUS &&
  30                  chan->flags & IEEE80211_CHAN_NO_HT40PLUS)
  31                 return NULL;
  32
  33         ht_cap = &rdev->wiphy.bands[chan->band]->ht_cap;
  34
  35         if (channel_type != NL80211_CHAN_NO_HT) {
  36                 if (!ht_cap->ht_supported)
  37                         return NULL;
  38
  39                 if (channel_type != NL80211_CHAN_HT20 &&
  40                     (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
  41                     ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT))
  42                         return NULL;
  43         }
  44
  45         return chan;
  46 }
  47
  48 bool cfg80211_can_beacon_sec_chan(struct wiphy *wiphy,
  49                                   struct ieee80211_channel *chan,
  50                                   enum nl80211_channel_type channel_type)
  51 {
  52         struct ieee80211_channel *sec_chan;
  53         int diff;
  54
  55         switch (channel_type) {
  56         case NL80211_CHAN_HT40PLUS:
  57                 diff = 20;
  58                 break;
  59         case NL80211_CHAN_HT40MINUS:
  60                 diff = -20;
  61                 break;
  62         default:
  63                 return true;
  64         }
  65
  66         sec_chan = ieee80211_get_channel(wiphy, chan->center_freq + diff);
  67         if (!sec_chan)
  68                 return false;
  69
  70         /* we'll need a DFS capability later */
  71         if (sec_chan->flags & (IEEE80211_CHAN_DISABLED |
  72                                IEEE80211_CHAN_PASSIVE_SCAN |
  73                                IEEE80211_CHAN_NO_IBSS |
  74                                IEEE80211_CHAN_RADAR))
  75                 return false;
  76
  77         return true;
  78 }
  79 EXPORT_SYMBOL(cfg80211_can_beacon_sec_chan);
  80
  81 int cfg80211_set_monitor_channel(struct cfg80211_registered_device *rdev,
  82                                  int freq, enum nl80211_channel_type chantype)
  83 {
  84         struct ieee80211_channel *chan;
  85
  86         if (!rdev->ops->set_monitor_channel)
  87                 return -EOPNOTSUPP;
  88         if (!cfg80211_has_monitors_only(rdev))
  89                 return -EBUSY;
  90
  91         chan = rdev_freq_to_chan(rdev, freq, chantype);
  92         if (!chan)
  93                 return -EINVAL;
  94
  95         return rdev->ops->set_monitor_channel(&rdev->wiphy, chan, chantype);
  96 }
  97
  98 void
  99 cfg80211_get_chan_state(struct wireless_dev *wdev,
 100                         struct ieee80211_channel **chan,
 101                         enum cfg80211_chan_mode *chanmode)
 102 {
 103         *chan = NULL;
 104         *chanmode = CHAN_MODE_UNDEFINED;
 105
 106         ASSERT_WDEV_LOCK(wdev);
 107
 108         if (!netif_running(wdev->netdev))
 109                 return;
 110
 111         switch (wdev->iftype) {
 112         case NL80211_IFTYPE_ADHOC:
 113                 if (wdev->current_bss) {
 114                         *chan = wdev->current_bss->pub.channel;
 115                         *chanmode = wdev->ibss_fixed
 116                                   ? CHAN_MODE_SHARED
 117                                   : CHAN_MODE_EXCLUSIVE;
 118                         return;
 119                 }
 120         case NL80211_IFTYPE_STATION:
 121         case NL80211_IFTYPE_P2P_CLIENT:
 122                 if (wdev->current_bss) {
 123                         *chan = wdev->current_bss->pub.channel;
 124                         *chanmode = CHAN_MODE_SHARED;
 125                         return;
 126                 }
 127                 break;
 128         case NL80211_IFTYPE_AP:
 129         case NL80211_IFTYPE_P2P_GO:
 130                 if (wdev->beacon_interval) {
 131                         *chan = wdev->channel;
 132                         *chanmode = CHAN_MODE_SHARED;
 133                 }
 134                 return;
 135         case NL80211_IFTYPE_MESH_POINT:
 136                 if (wdev->mesh_id_len) {
 137                         *chan = wdev->channel;
 138                         *chanmode = CHAN_MODE_SHARED;
 139                 }
 140                 return;
 141         case NL80211_IFTYPE_MONITOR:
 142         case NL80211_IFTYPE_AP_VLAN:
 143         case NL80211_IFTYPE_WDS:
 144                 /* these interface types don't really have a channel */
 145                 return;
 146         case NL80211_IFTYPE_UNSPECIFIED:
 147         case NUM_NL80211_IFTYPES:
 148                 WARN_ON(1);
 149         }
 150
 151         return;
 152 }