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                 if (sdata->vif.type == NL80211_IFTYPE_MONITOR)
  24                         continue;
  25
  26                 if (sdata->vif.type == NL80211_IFTYPE_STATION &&
  27                     !sdata->u.mgd.associated)
  28                         continue;
  29
  30                 if (sdata->vif.type == 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                 }
  36
  37                 if (sdata->vif.type == NL80211_IFTYPE_AP &&
  38                     !sdata->u.ap.beacon)
  39                         continue;
  40
  41                 return CHAN_MODE_FIXED;
  42         }
  43
  44         return CHAN_MODE_UNDEFINED;
  45 }
  46
  47 enum ieee80211_chan_mode
  48 ieee80211_get_channel_mode(struct ieee80211_local *local,
  49                            struct ieee80211_sub_if_data *ignore)
  50 {
  51         enum ieee80211_chan_mode mode;
  52
  53         mutex_lock(&local->iflist_mtx);
  54         mode = __ieee80211_get_channel_mode(local, ignore);
  55         mutex_unlock(&local->iflist_mtx);
  56
  57         return mode;
  58 }
  59
  60 bool ieee80211_set_channel_type(struct ieee80211_local *local,
  61                                 struct ieee80211_sub_if_data *sdata,
  62                                 enum nl80211_channel_type chantype)
  63 {
  64         struct ieee80211_sub_if_data *tmp;
  65         enum nl80211_channel_type superchan = NL80211_CHAN_NO_HT;
  66         bool result;
  67
  68         mutex_lock(&local->iflist_mtx);
  69
  70         list_for_each_entry(tmp, &local->interfaces, list) {
  71                 if (tmp == sdata)
  72                         continue;
  73
  74                 if (!ieee80211_sdata_running(tmp))
  75                         continue;
  76
  77                 switch (tmp->vif.bss_conf.channel_type) {
  78                 case NL80211_CHAN_NO_HT:
  79                 case NL80211_CHAN_HT20:
  80                         superchan = tmp->vif.bss_conf.channel_type;
  81                         break;
  82                 case NL80211_CHAN_HT40PLUS:
  83                         WARN_ON(superchan == NL80211_CHAN_HT40MINUS);
  84                         superchan = NL80211_CHAN_HT40PLUS;
  85                         break;
  86                 case NL80211_CHAN_HT40MINUS:
  87                         WARN_ON(superchan == NL80211_CHAN_HT40PLUS);
  88                         superchan = NL80211_CHAN_HT40MINUS;
  89                         break;
  90                 }
  91         }
  92
  93         switch (superchan) {
  94         case NL80211_CHAN_NO_HT:
  95         case NL80211_CHAN_HT20:
  96                 /*
  97                  * allow any change that doesn't go to no-HT
  98                  * (if it already is no-HT no change is needed)
  99                  */
 100                 if (chantype == NL80211_CHAN_NO_HT)
 101                         break;
 102                 superchan = chantype;
 103                 break;
 104         case NL80211_CHAN_HT40PLUS:
 105         case NL80211_CHAN_HT40MINUS:
 106                 /* allow smaller bandwidth and same */
 107                 if (chantype == NL80211_CHAN_NO_HT)
 108                         break;
 109                 if (chantype == NL80211_CHAN_HT20)
 110                         break;
 111                 if (superchan == chantype)
 112                         break;
 113                 result = false;
 114                 goto out;
 115         }
 116
 117         local->_oper_channel_type = superchan;
 118
 119         if (sdata)
 120                 sdata->vif.bss_conf.channel_type = chantype;
 121
 122         result = true;
 123  out:
 124         mutex_unlock(&local->iflist_mtx);
 125
 126         return result;
 127 }