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 13 struct ieee80211_channel * 14 rdev_freq_to_chan(struct cfg80211_registered_device *rdev, 15 int freq, enum nl80211_channel_type channel_type) 16 { 17 struct ieee80211_channel *chan; 18 struct ieee80211_sta_ht_cap *ht_cap; 19 20 chan = ieee80211_get_channel(&rdev->wiphy, freq); 21 22 /* Primary channel not allowed */ 23 if (!chan || chan->flags & IEEE80211_CHAN_DISABLED) 24 return NULL; 25 26 if (channel_type == NL80211_CHAN_HT40MINUS && 27 chan->flags & IEEE80211_CHAN_NO_HT40MINUS) 28 return NULL; 29 else if (channel_type == NL80211_CHAN_HT40PLUS && 30 chan->flags & IEEE80211_CHAN_NO_HT40PLUS) 31 return NULL; 32 33 ht_cap = &rdev->wiphy.bands[chan->band]->ht_cap; 34 35 if (channel_type != NL80211_CHAN_NO_HT) { 36 if (!ht_cap->ht_supported) 37 return NULL; 38 39 if (channel_type != NL80211_CHAN_HT20 && 40 (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) || 41 ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT)) 42 return NULL; 43 } 44 45 return chan; 46 } 47 48 int cfg80211_can_beacon_sec_chan(struct wiphy *wiphy, 49 struct ieee80211_channel *chan, 50 enum nl80211_channel_type channel_type) 51 { 52 struct ieee80211_channel *sec_chan; 53 int diff; 54 55 switch (channel_type) { 56 case NL80211_CHAN_HT40PLUS: 57 diff = 20; 58 break; 59 case NL80211_CHAN_HT40MINUS: 60 diff = -20; 61 break; 62 default: 63 return false; 64 } 65 66 sec_chan = ieee80211_get_channel(wiphy, chan->center_freq + diff); 67 if (!sec_chan) 68 return false; 69 70 /* we'll need a DFS capability later */ 71 if (sec_chan->flags & (IEEE80211_CHAN_DISABLED | 72 IEEE80211_CHAN_PASSIVE_SCAN | 73 IEEE80211_CHAN_NO_IBSS | 74 IEEE80211_CHAN_RADAR)) 75 return false; 76 77 return true; 78 } 79 EXPORT_SYMBOL(cfg80211_can_beacon_sec_chan); 80 81 int cfg80211_set_freq(struct cfg80211_registered_device *rdev, 82 struct wireless_dev *wdev, int freq, 83 enum nl80211_channel_type channel_type) 84 { 85 struct ieee80211_channel *chan; 86 int result; 87 88 if (wdev && wdev->iftype == NL80211_IFTYPE_MONITOR) 89 wdev = NULL; 90 91 if (wdev) { 92 ASSERT_WDEV_LOCK(wdev); 93 94 if (!netif_running(wdev->netdev)) 95 return -ENETDOWN; 96 } 97 98 if (!rdev->ops->set_channel) 99 return -EOPNOTSUPP; 100 101 chan = rdev_freq_to_chan(rdev, freq, channel_type); 102 if (!chan) 103 return -EINVAL; 104 105 /* Both channels should be able to initiate communication */ 106 if (wdev && (wdev->iftype == NL80211_IFTYPE_ADHOC || 107 wdev->iftype == NL80211_IFTYPE_AP || 108 wdev->iftype == NL80211_IFTYPE_AP_VLAN || 109 wdev->iftype == NL80211_IFTYPE_MESH_POINT || 110 wdev->iftype == NL80211_IFTYPE_P2P_GO)) { 111 switch (channel_type) { 112 case NL80211_CHAN_HT40PLUS: 113 case NL80211_CHAN_HT40MINUS: 114 if (!cfg80211_can_beacon_sec_chan(&rdev->wiphy, chan, 115 channel_type)) { 116 printk(KERN_DEBUG 117 "cfg80211: Secondary channel not " 118 "allowed to initiate communication\n"); 119 return -EINVAL; 120 } 121 break; 122 default: 123 break; 124 } 125 } 126 127 result = rdev->ops->set_channel(&rdev->wiphy, 128 wdev ? wdev->netdev : NULL, 129 chan, channel_type); 130 if (result) 131 return result; 132 133 if (wdev) 134 wdev->channel = chan; 135 136 return 0; 137 } 138