1 files changed, 135 insertions, 0 deletions
diff --git a/net/wireless/chan.c b/net/wireless/chan.c
new file mode 100644
index 00000000..17cd0c04
--- /dev/null
+++ b/net/wireless/chan.c
@@ -0,0 +1,135 @@
+/*
+ * 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_freq_to_chan(struct cfg80211_registered_device *rdev,
+		  int freq, enum nl80211_channel_type channel_type)
+{
+	struct ieee80211_channel *chan;
+	struct ieee80211_sta_ht_cap *ht_cap;
+
+	chan = ieee80211_get_channel(&rdev->wiphy, freq);
+
+	/* Primary channel not allowed */
+	if (!chan || chan->flags & IEEE80211_CHAN_DISABLED)
+		return NULL;
+
+	if (channel_type == NL80211_CHAN_HT40MINUS &&
+	    chan->flags & IEEE80211_CHAN_NO_HT40MINUS)
+		return NULL;
+	else if (channel_type == NL80211_CHAN_HT40PLUS &&
+		 chan->flags & IEEE80211_CHAN_NO_HT40PLUS)
+		return NULL;
+
+	ht_cap = &rdev->wiphy.bands[chan->band]->ht_cap;
+
+	if (channel_type != NL80211_CHAN_NO_HT) {
+		if (!ht_cap->ht_supported)
+			return NULL;
+
+		if (channel_type != NL80211_CHAN_HT20 &&
+		    (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
+		    ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT))
+			return NULL;
+	}
+
+	return chan;
+}
+
+static bool can_beacon_sec_chan(struct wiphy *wiphy,
+				struct ieee80211_channel *chan,
+				enum nl80211_channel_type channel_type)
+{
+	struct ieee80211_channel *sec_chan;
+	int diff;
+
+	switch (channel_type) {
+	case NL80211_CHAN_HT40PLUS:
+		diff = 20;
+		break;
+	case NL80211_CHAN_HT40MINUS:
+		diff = -20;
+		break;
+	default:
+		return false;
+	}
+
+	sec_chan = ieee80211_get_channel(wiphy, chan->center_freq + diff);
+	if (!sec_chan)
+		return false;
+
+	/* we'll need a DFS capability later */
+	if (sec_chan->flags & (IEEE80211_CHAN_DISABLED |
+			       IEEE80211_CHAN_PASSIVE_SCAN |
+			       IEEE80211_CHAN_NO_IBSS |
+			       IEEE80211_CHAN_RADAR))
+		return false;
+
+	return true;
+}
+
+int cfg80211_set_freq(struct cfg80211_registered_device *rdev,
+		      struct wireless_dev *wdev, int freq,
+		      enum nl80211_channel_type channel_type)
+{
+	struct ieee80211_channel *chan;
+	int result;
+
+	if (wdev && wdev->iftype == NL80211_IFTYPE_MONITOR)
+		wdev = NULL;
+
+	if (wdev) {
+		ASSERT_WDEV_LOCK(wdev);
+
+		if (!netif_running(wdev->netdev))
+			return -ENETDOWN;
+	}
+
+	if (!rdev->ops->set_channel)
+		return -EOPNOTSUPP;
+
+	chan = rdev_freq_to_chan(rdev, freq, channel_type);
+	if (!chan)
+		return -EINVAL;
+
+	/* Both channels should be able to initiate communication */
+	if (wdev && (wdev->iftype == NL80211_IFTYPE_ADHOC ||
+		     wdev->iftype == NL80211_IFTYPE_AP ||
+		     wdev->iftype == NL80211_IFTYPE_AP_VLAN ||
+		     wdev->iftype == NL80211_IFTYPE_MESH_POINT ||
+		     wdev->iftype == NL80211_IFTYPE_P2P_GO)) {
+		switch (channel_type) {
+		case NL80211_CHAN_HT40PLUS:
+		case NL80211_CHAN_HT40MINUS:
+			if (!can_beacon_sec_chan(&rdev->wiphy, chan,
+						 channel_type)) {
+				printk(KERN_DEBUG
+				       "cfg80211: Secondary channel not "
+				       "allowed to initiate communication\n");
+				return -EINVAL;
+			}
+			break;
+		default:
+			break;
+		}
+	}
+
+	result = rdev->ops->set_channel(&rdev->wiphy,
+					wdev ? wdev->netdev : NULL,
+					chan, channel_type);
+	if (result)
+		return result;
+
+	if (wdev)
+		wdev->channel = chan;
+
+	return 0;
+}