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 #include "rdev-ops.h"
  13
  14 struct ieee80211_channel *
  15 rdev_freq_to_chan(struct cfg80211_registered_device *rdev,
  16                   int freq, enum nl80211_channel_type channel_type)
  17 {
  18         struct ieee80211_channel *chan;
  19         struct ieee80211_sta_ht_cap *ht_cap;
  20
  21         chan = ieee80211_get_channel(&rdev->wiphy, freq);
  22
  23         /* Primary channel not allowed */
  24         if (!chan || chan->flags & IEEE80211_CHAN_DISABLED)
  25                 return NULL;
  26
  27         if (channel_type == NL80211_CHAN_HT40MINUS &&
  28             chan->flags & IEEE80211_CHAN_NO_HT40MINUS)
  29                 return NULL;
  30         else if (channel_type == NL80211_CHAN_HT40PLUS &&
  31                  chan->flags & IEEE80211_CHAN_NO_HT40PLUS)
  32                 return NULL;
  33
  34         ht_cap = &rdev->wiphy.bands[chan->band]->ht_cap;
  35
  36         if (channel_type != NL80211_CHAN_NO_HT) {
  37                 if (!ht_cap->ht_supported)
  38                         return NULL;
  39
  40                 if (channel_type != NL80211_CHAN_HT20 &&
  41                     (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
  42                     ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT))
  43                         return NULL;
  44         }
  45
  46         return chan;
  47 }
  48
  49 bool cfg80211_can_beacon_sec_chan(struct wiphy *wiphy,
  50                                   struct ieee80211_channel *chan,
  51                                   enum nl80211_channel_type channel_type)
  52 {
  53         struct ieee80211_channel *sec_chan;
  54         int diff;
  55
  56         trace_cfg80211_can_beacon_sec_chan(wiphy, chan, channel_type);
  57
  58         switch (channel_type) {
  59         case NL80211_CHAN_HT40PLUS:
  60                 diff = 20;
  61                 break;
  62         case NL80211_CHAN_HT40MINUS:
  63                 diff = -20;
  64                 break;
  65         default:
  66                 trace_cfg80211_return_bool(true);
  67                 return true;
  68         }
  69
  70         sec_chan = ieee80211_get_channel(wiphy, chan->center_freq + diff);
  71         if (!sec_chan) {
  72                 trace_cfg80211_return_bool(false);
  73                 return false;
  74         }
  75
  76         /* we'll need a DFS capability later */
  77         if (sec_chan->flags & (IEEE80211_CHAN_DISABLED |
  78                                IEEE80211_CHAN_PASSIVE_SCAN |
  79                                IEEE80211_CHAN_NO_IBSS |
  80                                IEEE80211_CHAN_RADAR)) {
  81                 trace_cfg80211_return_bool(false);
  82                 return false;
  83         }
  84         trace_cfg80211_return_bool(true);
  85         return true;
  86 }
  87 EXPORT_SYMBOL(cfg80211_can_beacon_sec_chan);
  88
  89 int cfg80211_set_monitor_channel(struct cfg80211_registered_device *rdev,
  90                                  int freq, enum nl80211_channel_type chantype)
  91 {
  92         struct ieee80211_channel *chan;
  93
  94         if (!rdev->ops->set_monitor_channel)
  95                 return -EOPNOTSUPP;
  96         if (!cfg80211_has_monitors_only(rdev))
  97                 return -EBUSY;
  98
  99         chan = rdev_freq_to_chan(rdev, freq, chantype);
 100         if (!chan)
 101                 return -EINVAL;
 102
 103         return rdev_set_monitor_channel(rdev, chan, chantype);
 104 }
 105
 106 void
 107 cfg80211_get_chan_state(struct wireless_dev *wdev,
 108                         struct ieee80211_channel **chan,
 109                         enum cfg80211_chan_mode *chanmode)
 110 {
 111         *chan = NULL;
 112         *chanmode = CHAN_MODE_UNDEFINED;
 113
 114         ASSERT_WDEV_LOCK(wdev);
 115
 116         if (wdev->netdev && !netif_running(wdev->netdev))
 117                 return;
 118
 119         switch (wdev->iftype) {
 120         case NL80211_IFTYPE_ADHOC:
 121                 if (wdev->current_bss) {
 122                         *chan = wdev->current_bss->pub.channel;
 123                         *chanmode = wdev->ibss_fixed
 124                                   ? CHAN_MODE_SHARED
 125                                   : CHAN_MODE_EXCLUSIVE;
 126                         return;
 127                 }
 128         case NL80211_IFTYPE_STATION:
 129         case NL80211_IFTYPE_P2P_CLIENT:
 130                 if (wdev->current_bss) {
 131                         *chan = wdev->current_bss->pub.channel;
 132                         *chanmode = CHAN_MODE_SHARED;
 133                         return;
 134                 }
 135                 break;
 136         case NL80211_IFTYPE_AP:
 137         case NL80211_IFTYPE_P2P_GO:
 138                 if (wdev->beacon_interval) {
 139                         *chan = wdev->channel;
 140                         *chanmode = CHAN_MODE_SHARED;
 141                 }
 142                 return;
 143         case NL80211_IFTYPE_MESH_POINT:
 144                 if (wdev->mesh_id_len) {
 145                         *chan = wdev->channel;
 146                         *chanmode = CHAN_MODE_SHARED;
 147                 }
 148                 return;
 149         case NL80211_IFTYPE_MONITOR:
 150         case NL80211_IFTYPE_AP_VLAN:
 151         case NL80211_IFTYPE_WDS:
 152                 /* these interface types don't really have a channel */
 153                 return;
 154         case NL80211_IFTYPE_P2P_DEVICE:
 155                 if (wdev->wiphy->features &
 156                                 NL80211_FEATURE_P2P_DEVICE_NEEDS_CHANNEL)
 157                         *chanmode = CHAN_MODE_EXCLUSIVE;
 158                 return;
 159         case NL80211_IFTYPE_UNSPECIFIED:
 160         case NUM_NL80211_IFTYPES:
 161                 WARN_ON(1);
 162         }
 163
 164         return;
 165 }