net/mac80211/chan.c

   1 /*
   2  * mac80211 - channel management
   3  */
   4
   5 #include <linux/nl80211.h>
   6 #include <net/cfg80211.h>
   7 #include "ieee80211_i.h"
   8
   9 static enum ieee80211_chan_mode
  10 __ieee80211_get_channel_mode(struct ieee80211_local *local,
  11                              struct ieee80211_sub_if_data *ignore)
  12 {
  13         struct ieee80211_sub_if_data *sdata;
  14
  15         lockdep_assert_held(&local->iflist_mtx);
  16
  17         list_for_each_entry(sdata, &local->interfaces, list) {
  18                 if (sdata == ignore)
  19                         continue;
  20
  21                 if (!ieee80211_sdata_running(sdata))
  22                         continue;
  23
  24                 switch (sdata->vif.type) {
  25                 case NL80211_IFTYPE_MONITOR:
  26                         continue;
  27                 case NL80211_IFTYPE_STATION:
  28                         if (!sdata->u.mgd.associated)
  29                                 continue;
  30                         break;
  31                 case NL80211_IFTYPE_ADHOC:
  32                         if (!sdata->u.ibss.ssid_len)
  33                                 continue;
  34                         if (!sdata->u.ibss.fixed_channel)
  35                                 return CHAN_MODE_HOPPING;
  36                         break;
  37                 case NL80211_IFTYPE_AP_VLAN:
  38                         /* will also have _AP interface */
  39                         continue;
  40                 case NL80211_IFTYPE_AP:
  41                         if (!sdata->u.ap.beacon)
  42                                 continue;
  43                         break;
  44                 default:
  45                         break;
  46                 }
  47
  48                 return CHAN_MODE_FIXED;
  49         }
  50
  51         return CHAN_MODE_UNDEFINED;
  52 }
  53
  54 enum ieee80211_chan_mode
  55 ieee80211_get_channel_mode(struct ieee80211_local *local,
  56                            struct ieee80211_sub_if_data *ignore)
  57 {
  58         enum ieee80211_chan_mode mode;
  59
  60         mutex_lock(&local->iflist_mtx);
  61         mode = __ieee80211_get_channel_mode(local, ignore);
  62         mutex_unlock(&local->iflist_mtx);
  63
  64         return mode;
  65 }
  66
  67 bool ieee80211_set_channel_type(struct ieee80211_local *local,
  68                                 struct ieee80211_sub_if_data *sdata,
  69                                 enum nl80211_channel_type chantype)
  70 {
  71         struct ieee80211_sub_if_data *tmp;
  72         enum nl80211_channel_type superchan = NL80211_CHAN_NO_HT;
  73         bool result;
  74
  75         mutex_lock(&local->iflist_mtx);
  76
  77         list_for_each_entry(tmp, &local->interfaces, list) {
  78                 if (tmp == sdata)
  79                         continue;
  80
  81                 if (!ieee80211_sdata_running(tmp))
  82                         continue;
  83
  84                 switch (tmp->vif.bss_conf.channel_type) {
  85                 case NL80211_CHAN_NO_HT:
  86                 case NL80211_CHAN_HT20:
  87                         if (superchan > tmp->vif.bss_conf.channel_type)
  88                                 break;
  89
  90                         superchan = tmp->vif.bss_conf.channel_type;
  91                         break;
  92                 case NL80211_CHAN_HT40PLUS:
  93                         WARN_ON(superchan == NL80211_CHAN_HT40MINUS);
  94                         superchan = NL80211_CHAN_HT40PLUS;
  95                         break;
  96                 case NL80211_CHAN_HT40MINUS:
  97                         WARN_ON(superchan == NL80211_CHAN_HT40PLUS);
  98                         superchan = NL80211_CHAN_HT40MINUS;
  99                         break;
 100                 }
 101         }
 102
 103         switch (superchan) {
 104         case NL80211_CHAN_NO_HT:
 105         case NL80211_CHAN_HT20:
 106                 /*
 107                  * allow any change that doesn't go to no-HT
 108                  * (if it already is no-HT no change is needed)
 109                  */
 110                 if (chantype == NL80211_CHAN_NO_HT)
 111                         break;
 112                 superchan = chantype;
 113                 break;
 114         case NL80211_CHAN_HT40PLUS:
 115         case NL80211_CHAN_HT40MINUS:
 116                 /* allow smaller bandwidth and same */
 117                 if (chantype == NL80211_CHAN_NO_HT)
 118                         break;
 119                 if (chantype == NL80211_CHAN_HT20)
 120                         break;
 121                 if (superchan == chantype)
 122                         break;
 123                 result = false;
 124                 goto out;
 125         }
 126
 127         local->_oper_channel_type = superchan;
 128
 129         if (sdata)
 130                 sdata->vif.bss_conf.channel_type = chantype;
 131
 132         result = true;
 133  out:
 134         mutex_unlock(&local->iflist_mtx);
 135
 136         return result;
 137 }
 138
 139 /*
 140  * ieee80211_get_tx_channel_type returns the channel type we should
 141  * use for packet transmission, given the channel capability and
 142  * whatever regulatory flags we have been given.
 143  */
 144 enum nl80211_channel_type ieee80211_get_tx_channel_type(
 145                                 struct ieee80211_local *local,
 146                                 enum nl80211_channel_type channel_type)
 147 {
 148         switch (channel_type) {
 149         case NL80211_CHAN_HT40PLUS:
 150                 if (local->hw.conf.channel->flags &
 151                                 IEEE80211_CHAN_NO_HT40PLUS)
 152                         return NL80211_CHAN_HT20;
 153                 break;
 154         case NL80211_CHAN_HT40MINUS:
 155                 if (local->hw.conf.channel->flags &
 156                                 IEEE80211_CHAN_NO_HT40MINUS)
 157                         return NL80211_CHAN_HT20;
 158                 break;
 159         default:
 160                 break;
 161         }
 162         return channel_type;
 163 }