cfg80211: provide channel to start_ap function

Instead of setting the channel first and then
starting the AP, let cfg80211 store the channel
and provide it as one of the AP settings.

This means that now you have to set the channel
before you can start an AP interface, but since
hostapd/wpa_supplicant always do that we're OK
with this change.

Alternatively, it's now possible to give the
channel as an attribute to the start-ap nl80211
command, overriding any preset channel.

Cc: Kalle Valo <kvalo@qca.qualcomm.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath6kl/cfg80211.c

@@ -2585,35 +2585,6 @@ static int ath6kl_set_ies(struct ath6kl_vif *vif,
 	return 0;
 }
 
-static int ath6kl_set_channel(struct wiphy *wiphy, struct net_device *dev,
-			      struct ieee80211_channel *chan,
-			      enum nl80211_channel_type channel_type)
-{
-	struct ath6kl_vif *vif;
-
-	/*
-	 * 'dev' could be NULL if a channel change is required for the hardware
-	 * device itself, instead of a particular VIF.
-	 *
-	 * FIXME: To be handled properly when monitor mode is supported.
-	 */
-	if (!dev)
-		return -EBUSY;
-
-	vif = netdev_priv(dev);
-
-	if (!ath6kl_cfg80211_ready(vif))
-		return -EIO;
-
-	ath6kl_dbg(ATH6KL_DBG_WLAN_CFG, "%s: center_freq=%u hw_value=%u\n",
-		   __func__, chan->center_freq, chan->hw_value);
-	vif->next_chan = chan->center_freq;
-	vif->next_ch_type = channel_type;
-	vif->next_ch_band = chan->band;
-
-	return 0;
-}
-
 static int ath6kl_get_rsn_capab(struct cfg80211_beacon_data *beacon,
 				u8 *rsn_capab)
 {
@@ -2791,7 +2762,7 @@ static int ath6kl_start_ap(struct wiphy *wiphy, struct net_device *dev,
 	p.ssid_len = vif->ssid_len;
 	memcpy(p.ssid, vif->ssid, vif->ssid_len);
 	p.dot11_auth_mode = vif->dot11_auth_mode;
-	p.ch = cpu_to_le16(vif->next_chan);
+	p.ch = cpu_to_le16(info->channel->center_freq);
 
 	/* Enable uAPSD support by default */
 	res = ath6kl_wmi_ap_set_apsd(ar->wmi, vif->fw_vif_idx, true);
@@ -2815,8 +2786,8 @@ static int ath6kl_start_ap(struct wiphy *wiphy, struct net_device *dev,
 			return res;
 	}
 
-	if (ath6kl_set_htcap(vif, vif->next_ch_band,
-			     vif->next_ch_type != NL80211_CHAN_NO_HT))
+	if (ath6kl_set_htcap(vif, info->channel->band,
+			     info->channel_type != NL80211_CHAN_NO_HT))
 		return -EIO;
 
 	/*
@@ -3271,7 +3242,6 @@ static struct cfg80211_ops ath6kl_cfg80211_ops = {
 	.suspend = __ath6kl_cfg80211_suspend,
 	.resume = __ath6kl_cfg80211_resume,
 #endif
-	.set_channel = ath6kl_set_channel,
 	.start_ap = ath6kl_start_ap,
 	.change_beacon = ath6kl_change_beacon,
 	.stop_ap = ath6kl_stop_ap,

drivers/net/wireless/ath/ath6kl/core.h

@@ -553,9 +553,6 @@ struct ath6kl_vif {
 	u32 last_cancel_roc_id;
 	u32 send_action_id;
 	bool probe_req_report;
-	u16 next_chan;
-	enum nl80211_channel_type next_ch_type;
-	enum ieee80211_band next_ch_band;
 	u16 assoc_bss_beacon_int;
 	u16 listen_intvl_t;
 	u16 bmiss_time_t;

drivers/net/wireless/ath/ath6kl/main.c

@@ -598,7 +598,6 @@ static int ath6kl_commit_ch_switch(struct ath6kl_vif *vif, u16 channel)
 
 	struct ath6kl *ar = vif->ar;
 
-	vif->next_chan = channel;
 	vif->profile.ch = cpu_to_le16(channel);
 
 	switch (vif->nw_type) {

include/linux/nl80211.h

@@ -170,6 +170,8 @@
  *	%NL80211_ATTR_CIPHER_GROUP, %NL80211_ATTR_WPA_VERSIONS,
  *	%NL80211_ATTR_AKM_SUITES, %NL80211_ATTR_PRIVACY,
  *	%NL80211_ATTR_AUTH_TYPE and %NL80211_ATTR_INACTIVITY_TIMEOUT.
+ *	The channel to use can be set on the interface or be given using the
+ *	%NL80211_ATTR_WIPHY_FREQ and %NL80211_ATTR_WIPHY_CHANNEL_TYPE attrs.
  * @NL80211_CMD_NEW_BEACON: old alias for %NL80211_CMD_START_AP
  * @NL80211_CMD_STOP_AP: Stop AP operation on the given interface
  * @NL80211_CMD_DEL_BEACON: old alias for %NL80211_CMD_STOP_AP

include/net/cfg80211.h

@@ -404,6 +404,8 @@ struct cfg80211_beacon_data {
  *
  * Used to configure an AP interface.
  *
+ * @channel: the channel to start the AP on
+ * @channel_type: the channel type to use
  * @beacon: beacon data
  * @beacon_interval: beacon interval
  * @dtim_period: DTIM period
@@ -417,6 +419,9 @@ struct cfg80211_beacon_data {
  * @inactivity_timeout: time in seconds to determine station's inactivity.
  */
 struct cfg80211_ap_settings {
+	struct ieee80211_channel *channel;
+	enum nl80211_channel_type channel_type;
+
 	struct cfg80211_beacon_data beacon;
 
 	int beacon_interval, dtim_period;
@@ -2263,7 +2268,10 @@ struct cfg80211_cached_keys;
  * @netdev: (private) Used to reference back to the netdev
  * @current_bss: (private) Used by the internal configuration code
  * @channel: (private) Used by the internal configuration code to track
- *	user-set AP, monitor and WDS channels for wireless extensions
+ *	the user-set AP, monitor and WDS channel
+ * @preset_chan: (private) Used by the internal configuration code to
+ *	track the channel to be used for AP later
+ * @preset_chantype: (private) the corresponding channel type
  * @bssid: (private) Used by the internal configuration code
  * @ssid: (private) Used by the internal configuration code
  * @ssid_len: (private) Used by the internal configuration code
@@ -2314,6 +2322,8 @@ struct wireless_dev {
 
 	struct cfg80211_internal_bss *current_bss; /* associated / joined */
 	struct ieee80211_channel *channel;
+	struct ieee80211_channel *preset_chan;
+	enum nl80211_channel_type preset_chantype;
 
 	bool ps;
 	int ps_timeout;

net/mac80211/cfg.c

@@ -823,6 +823,11 @@ static int ieee80211_start_ap(struct wiphy *wiphy, struct net_device *dev,
 	if (old)
 		return -EALREADY;
 
+	err = ieee80211_set_channel(wiphy, dev, params->channel,
+				    params->channel_type);
+	if (err)
+		return err;
+
 	/*
 	 * Apply control port protocol, this allows us to
 	 * not encrypt dynamic WEP control frames.

net/wireless/nl80211.c

@@ -921,7 +921,11 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
 		if (nla_put_u32(msg, i, NL80211_CMD_SET_WIPHY_NETNS))
 			goto nla_put_failure;
 	}
-	CMD(set_channel, SET_CHANNEL);
+	if (dev->ops->set_channel || dev->ops->start_ap) {
+		i++;
+		if (nla_put_u32(msg, i, NL80211_CMD_SET_CHANNEL))
+			goto nla_put_failure;
+	}
 	CMD(set_wds_peer, SET_WDS_PEER);
 	if (dev->wiphy.flags & WIPHY_FLAG_SUPPORTS_TDLS) {
 		CMD(tdls_mgmt, TDLS_MGMT);
@@ -1170,6 +1174,9 @@ static bool nl80211_can_set_dev_channel(struct wireless_dev *wdev)
 	 * Monitors are special as they are normally slaved to
 	 * whatever else is going on, so they behave as though
 	 * you tried setting the wiphy channel itself.
+	 *
+	 * For AP/GO modes, it's only for compatibility, you can
+	 * also give the channel to the start-AP command.
 	 */
 	return !wdev ||
 		wdev->iftype == NL80211_IFTYPE_AP ||
@@ -1204,6 +1211,7 @@ static int __nl80211_set_channel(struct cfg80211_registered_device *rdev,
 				 struct wireless_dev *wdev,
 				 struct genl_info *info)
 {
+	struct ieee80211_channel *channel;
 	enum nl80211_channel_type channel_type = NL80211_CHAN_NO_HT;
 	u32 freq;
 	int result;
@@ -1221,7 +1229,25 @@ static int __nl80211_set_channel(struct cfg80211_registered_device *rdev,
 	freq = nla_get_u32(info->attrs[NL80211_ATTR_WIPHY_FREQ]);
 
 	mutex_lock(&rdev->devlist_mtx);
-	if (wdev) {
+	if (wdev) switch (wdev->iftype) {
+	case NL80211_IFTYPE_AP:
+	case NL80211_IFTYPE_P2P_GO:
+		if (wdev->beacon_interval) {
+			result = -EBUSY;
+			break;
+		}
+		channel = rdev_freq_to_chan(rdev, freq, channel_type);
+		if (!channel || !cfg80211_can_beacon_sec_chan(&rdev->wiphy,
+							      channel,
+							      channel_type)) {
+			result = -EINVAL;
+			break;
+		}
+		wdev->preset_chan = channel;
+		wdev->preset_chantype = channel_type;
+		result = 0;
+		break;
+	default:
 		wdev_lock(wdev);
 		result = cfg80211_set_freq(rdev, wdev, freq, channel_type);
 		wdev_unlock(wdev);
@@ -2299,6 +2325,29 @@ static int nl80211_start_ap(struct sk_buff *skb, struct genl_info *info)
 			info->attrs[NL80211_ATTR_INACTIVITY_TIMEOUT]);
 	}
 
+	if (info->attrs[NL80211_ATTR_WIPHY_FREQ]) {
+		enum nl80211_channel_type channel_type = NL80211_CHAN_NO_HT;
+
+		if (info->attrs[NL80211_ATTR_WIPHY_CHANNEL_TYPE] &&
+		    !nl80211_valid_channel_type(info, &channel_type))
+			return -EINVAL;
+
+		params.channel = rdev_freq_to_chan(rdev,
+			nla_get_u32(info->attrs[NL80211_ATTR_WIPHY_FREQ]),
+			channel_type);
+		if (!params.channel)
+			return -EINVAL;
+		params.channel_type = channel_type;
+	} else if (wdev->preset_chan) {
+		params.channel = wdev->preset_chan;
+		params.channel_type = wdev->preset_chantype;
+	} else
+		return -EINVAL;
+
+	if (!cfg80211_can_beacon_sec_chan(&rdev->wiphy, params.channel,
+					  params.channel_type))
+		return -EINVAL;
+
 	err = rdev->ops->start_ap(&rdev->wiphy, dev, &params);
 	if (!err)
 		wdev->beacon_interval = params.beacon_interval;