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 <net/cfg80211.h>
  10 #include "core.h"
  11
  12 struct ieee80211_channel *
  13 rdev_freq_to_chan(struct cfg80211_registered_device *rdev,
  14                   int freq, enum nl80211_channel_type channel_type)
  15 {
  16         struct ieee80211_channel *chan;
  17         struct ieee80211_sta_ht_cap *ht_cap;
  18
  19         chan = ieee80211_get_channel(&rdev->wiphy, freq);
  20
  21         /* Primary channel not allowed */
  22         if (!chan || chan->flags & IEEE80211_CHAN_DISABLED)
  23                 return NULL;
  24
  25         if (channel_type == NL80211_CHAN_HT40MINUS &&
  26             chan->flags & IEEE80211_CHAN_NO_HT40MINUS)
  27                 return NULL;
  28         else if (channel_type == NL80211_CHAN_HT40PLUS &&
  29                  chan->flags & IEEE80211_CHAN_NO_HT40PLUS)
  30                 return NULL;
  31
  32         ht_cap = &rdev->wiphy.bands[chan->band]->ht_cap;
  33
  34         if (channel_type != NL80211_CHAN_NO_HT) {
  35                 if (!ht_cap->ht_supported)
  36                         return NULL;
  37
  38                 if (channel_type != NL80211_CHAN_HT20 &&
  39                     (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
  40                     ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT))
  41                         return NULL;
  42         }
  43
  44         return chan;
  45 }
  46
  47 int cfg80211_set_freq(struct cfg80211_registered_device *rdev,
  48                       struct wireless_dev *wdev, int freq,
  49                       enum nl80211_channel_type channel_type)
  50 {
  51         struct ieee80211_channel *chan;
  52         int result;
  53
  54         if (wdev && wdev->iftype == NL80211_IFTYPE_MONITOR)
  55                 wdev = NULL;
  56
  57         if (wdev) {
  58                 ASSERT_WDEV_LOCK(wdev);
  59
  60                 if (!netif_running(wdev->netdev))
  61                         return -ENETDOWN;
  62         }
  63
  64         if (!rdev->ops->set_channel)
  65                 return -EOPNOTSUPP;
  66
  67         chan = rdev_freq_to_chan(rdev, freq, channel_type);
  68         if (!chan)
  69                 return -EINVAL;
  70
  71         result = rdev->ops->set_channel(&rdev->wiphy,
  72                                         wdev ? wdev->netdev : NULL,
  73                                         chan, channel_type);
  74         if (result)
  75                 return result;
  76
  77         if (wdev)
  78                 wdev->channel = chan;
  79
  80         return 0;
  81 }