net/mac80211/chan.c

   1 /*
   2  * mac80211 - channel management
   3  */
   4
   5 #include <linux/nl80211.h>
   6 #include "ieee80211_i.h"
   7
   8 static enum ieee80211_chan_mode
   9 __ieee80211_get_channel_mode(struct ieee80211_local *local,
  10                              struct ieee80211_sub_if_data *ignore)
  11 {
  12         struct ieee80211_sub_if_data *sdata;
  13
  14         lockdep_assert_held(&local->iflist_mtx);
  15
  16         list_for_each_entry(sdata, &local->interfaces, list) {
  17                 if (sdata == ignore)
  18                         continue;
  19
  20                 if (!ieee80211_sdata_running(sdata))
  21                         continue;
  22
  23                 switch (sdata->vif.type) {
  24                 case NL80211_IFTYPE_MONITOR:
  25                         continue;
  26                 case NL80211_IFTYPE_STATION:
  27                         if (!sdata->u.mgd.associated)
  28                                 continue;
  29                         break;
  30                 case NL80211_IFTYPE_ADHOC:
  31                         if (!sdata->u.ibss.ssid_len)
  32                                 continue;
  33                         if (!sdata->u.ibss.fixed_channel)
  34                                 return CHAN_MODE_HOPPING;
  35                         break;
  36                 case NL80211_IFTYPE_AP_VLAN:
  37                         /* will also have _AP interface */
  38                         continue;
  39                 case NL80211_IFTYPE_AP:
  40                         if (!sdata->u.ap.beacon)
  41                                 continue;
  42                         break;
  43                 default:
  44                         break;
  45                 }
  46
  47                 return CHAN_MODE_FIXED;
  48         }
  49
  50         return CHAN_MODE_UNDEFINED;
  51 }
  52
  53 enum ieee80211_chan_mode
  54 ieee80211_get_channel_mode(struct ieee80211_local *local,
  55                            struct ieee80211_sub_if_data *ignore)
  56 {
  57         enum ieee80211_chan_mode mode;
  58
  59         mutex_lock(&local->iflist_mtx);
  60         mode = __ieee80211_get_channel_mode(local, ignore);
  61         mutex_unlock(&local->iflist_mtx);
  62
  63         return mode;
  64 }
  65
  66 bool ieee80211_set_channel_type(struct ieee80211_local *local,
  67                                 struct ieee80211_sub_if_data *sdata,
  68                                 enum nl80211_channel_type chantype)
  69 {
  70         struct ieee80211_sub_if_data *tmp;
  71         enum nl80211_channel_type superchan = NL80211_CHAN_NO_HT;
  72         bool result;
  73
  74         mutex_lock(&local->iflist_mtx);
  75
  76         list_for_each_entry(tmp, &local->interfaces, list) {
  77                 if (tmp == sdata)
  78                         continue;
  79
  80                 if (!ieee80211_sdata_running(tmp))
  81                         continue;
  82
  83                 switch (tmp->vif.bss_conf.channel_type) {
  84                 case NL80211_CHAN_NO_HT:
  85                 case NL80211_CHAN_HT20:
  86                         if (superchan > tmp->vif.bss_conf.channel_type)
  87                                 break;
  88
  89                         superchan = tmp->vif.bss_conf.channel_type;
  90                         break;
  91                 case NL80211_CHAN_HT40PLUS:
  92                         WARN_ON(superchan == NL80211_CHAN_HT40MINUS);
  93                         superchan = NL80211_CHAN_HT40PLUS;
  94                         break;
  95                 case NL80211_CHAN_HT40MINUS:
  96                         WARN_ON(superchan == NL80211_CHAN_HT40PLUS);
  97                         superchan = NL80211_CHAN_HT40MINUS;
  98                         break;
  99                 }
 100         }
 101
 102         switch (superchan) {
 103         case NL80211_CHAN_NO_HT:
 104         case NL80211_CHAN_HT20:
 105                 /*
 106                  * allow any change that doesn't go to no-HT
 107                  * (if it already is no-HT no change is needed)
 108                  */
 109                 if (chantype == NL80211_CHAN_NO_HT)
 110                         break;
 111                 superchan = chantype;
 112                 break;
 113         case NL80211_CHAN_HT40PLUS:
 114         case NL80211_CHAN_HT40MINUS:
 115                 /* allow smaller bandwidth and same */
 116                 if (chantype == NL80211_CHAN_NO_HT)
 117                         break;
 118                 if (chantype == NL80211_CHAN_HT20)
 119                         break;
 120                 if (superchan == chantype)
 121                         break;
 122                 result = false;
 123                 goto out;
 124         }
 125
 126         local->_oper_channel_type = superchan;
 127
 128         if (sdata)
 129                 sdata->vif.bss_conf.channel_type = chantype;
 130
 131         result = true;
 132  out:
 133         mutex_unlock(&local->iflist_mtx);
 134
 135         return result;
 136 }