138 lines
3.2 KiB
C
138 lines
3.2 KiB
C
/*
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* This file contains helper code to handle channel
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* settings and keeping track of what is possible at
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* any point in time.
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*
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* Copyright 2009 Johannes Berg <johannes@sipsolutions.net>
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*/
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#include <linux/export.h>
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#include <net/cfg80211.h>
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#include "core.h"
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struct ieee80211_channel *
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rdev_freq_to_chan(struct cfg80211_registered_device *rdev,
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int freq, enum nl80211_channel_type channel_type)
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{
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struct ieee80211_channel *chan;
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struct ieee80211_sta_ht_cap *ht_cap;
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chan = ieee80211_get_channel(&rdev->wiphy, freq);
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/* Primary channel not allowed */
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if (!chan || chan->flags & IEEE80211_CHAN_DISABLED)
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return NULL;
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if (channel_type == NL80211_CHAN_HT40MINUS &&
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chan->flags & IEEE80211_CHAN_NO_HT40MINUS)
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return NULL;
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else if (channel_type == NL80211_CHAN_HT40PLUS &&
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chan->flags & IEEE80211_CHAN_NO_HT40PLUS)
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return NULL;
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ht_cap = &rdev->wiphy.bands[chan->band]->ht_cap;
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if (channel_type != NL80211_CHAN_NO_HT) {
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if (!ht_cap->ht_supported)
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return NULL;
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if (channel_type != NL80211_CHAN_HT20 &&
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(!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
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ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT))
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return NULL;
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}
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return chan;
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}
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bool cfg80211_can_beacon_sec_chan(struct wiphy *wiphy,
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struct ieee80211_channel *chan,
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enum nl80211_channel_type channel_type)
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{
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struct ieee80211_channel *sec_chan;
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int diff;
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switch (channel_type) {
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case NL80211_CHAN_HT40PLUS:
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diff = 20;
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break;
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case NL80211_CHAN_HT40MINUS:
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diff = -20;
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break;
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default:
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return false;
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}
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sec_chan = ieee80211_get_channel(wiphy, chan->center_freq + diff);
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if (!sec_chan)
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return false;
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/* we'll need a DFS capability later */
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if (sec_chan->flags & (IEEE80211_CHAN_DISABLED |
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IEEE80211_CHAN_PASSIVE_SCAN |
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IEEE80211_CHAN_NO_IBSS |
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IEEE80211_CHAN_RADAR))
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return false;
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return true;
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}
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EXPORT_SYMBOL(cfg80211_can_beacon_sec_chan);
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int cfg80211_set_freq(struct cfg80211_registered_device *rdev,
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struct wireless_dev *wdev, int freq,
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enum nl80211_channel_type channel_type)
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{
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struct ieee80211_channel *chan;
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int result;
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if (wdev && wdev->iftype == NL80211_IFTYPE_MONITOR)
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wdev = NULL;
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if (wdev) {
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ASSERT_WDEV_LOCK(wdev);
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if (!netif_running(wdev->netdev))
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return -ENETDOWN;
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}
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if (!rdev->ops->set_channel)
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return -EOPNOTSUPP;
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chan = rdev_freq_to_chan(rdev, freq, channel_type);
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if (!chan)
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return -EINVAL;
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/* Both channels should be able to initiate communication */
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if (wdev && (wdev->iftype == NL80211_IFTYPE_ADHOC ||
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wdev->iftype == NL80211_IFTYPE_AP ||
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wdev->iftype == NL80211_IFTYPE_AP_VLAN ||
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wdev->iftype == NL80211_IFTYPE_MESH_POINT ||
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wdev->iftype == NL80211_IFTYPE_P2P_GO)) {
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switch (channel_type) {
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case NL80211_CHAN_HT40PLUS:
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case NL80211_CHAN_HT40MINUS:
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if (!cfg80211_can_beacon_sec_chan(&rdev->wiphy, chan,
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channel_type)) {
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printk(KERN_DEBUG
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"cfg80211: Secondary channel not "
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"allowed to initiate communication\n");
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return -EINVAL;
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}
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break;
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default:
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break;
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}
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}
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result = rdev->ops->set_channel(&rdev->wiphy,
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wdev ? wdev->netdev : NULL,
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chan, channel_type);
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if (result)
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return result;
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if (wdev)
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wdev->channel = chan;
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return 0;
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}
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