/* * This file contains helper code to handle channel * settings and keeping track of what is possible at * any point in time. * * Copyright 2009 Johannes Berg <johannes@sipsolutions.net> */ #include <net/cfg80211.h> #include "core.h" struct ieee80211_channel * rdev_fixed_channel(struct cfg80211_registered_device *rdev, struct wireless_dev *for_wdev) { struct wireless_dev *wdev; struct ieee80211_channel *result = NULL; WARN_ON(!mutex_is_locked(&rdev->devlist_mtx)); list_for_each_entry(wdev, &rdev->netdev_list, list) { if (wdev == for_wdev) continue; /* * Lock manually to tell lockdep about allowed * nesting here if for_wdev->mtx is held already. * This is ok as it's all under the rdev devlist * mutex and as such can only be done once at any * given time. */ mutex_lock_nested(&wdev->mtx, SINGLE_DEPTH_NESTING); if (wdev->current_bss) result = wdev->current_bss->pub.channel; wdev_unlock(wdev); if (result) break; } return result; } int rdev_set_freq(struct cfg80211_registered_device *rdev, struct wireless_dev *for_wdev, int freq, enum nl80211_channel_type channel_type) { struct ieee80211_channel *chan; struct ieee80211_sta_ht_cap *ht_cap; int result; if (rdev_fixed_channel(rdev, for_wdev)) return -EBUSY; if (!rdev->ops->set_channel) return -EOPNOTSUPP; chan = ieee80211_get_channel(&rdev->wiphy, freq); /* Primary channel not allowed */ if (!chan || chan->flags & IEEE80211_CHAN_DISABLED) return -EINVAL; if (channel_type == NL80211_CHAN_HT40MINUS && chan->flags & IEEE80211_CHAN_NO_HT40MINUS) return -EINVAL; else if (channel_type == NL80211_CHAN_HT40PLUS && chan->flags & IEEE80211_CHAN_NO_HT40PLUS) return -EINVAL; ht_cap = &rdev->wiphy.bands[chan->band]->ht_cap; if (channel_type != NL80211_CHAN_NO_HT) { if (!ht_cap->ht_supported) return -EINVAL; if (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) || ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT) return -EINVAL; } result = rdev->ops->set_channel(&rdev->wiphy, chan, channel_type); if (result) return result; rdev->channel = chan; return 0; }