[PATCH 0/3] AP mode channel setting simplification

[PATCH 0/3] AP mode channel setting simplification

[Johannes Berg]

Ath6kl stores the channel, while mac80211 tries to
immediately apply it. The latter isn't great for
multi-channel.

Change cfg80211 to store the channel, and give it
to the driver (mac80211, ath6kl, etc.) only in the
start_ap() function.

This simplifies ath6kl a lot, and while it doesn't
make a difference to mac80211 today I think it'll
make it simpler to implement multi-channel.

johannes

[PATCH 1/3] mac80211: move ieee80211_set_channel function

[Johannes Berg]

From: Johannes Berg <johannes.berg@intel.com>

Move the set_channel function up so it can be used
by other code in this file in the future.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 net/mac80211/cfg.c |   70 ++++++++++++++++++++++++++---------------------------
 1 file changed, 35 insertions(+), 35 deletions(-)

--- a/net/mac80211/cfg.c	2012-05-10 21:46:39.000000000 +0200
+++ b/net/mac80211/cfg.c	2012-05-10 21:47:10.000000000 +0200
@@ -674,6 +674,41 @@ static int ieee80211_get_station(struct
 	return ret;
 }
 
+static int ieee80211_set_channel(struct wiphy *wiphy,
+				 struct net_device *netdev,
+				 struct ieee80211_channel *chan,
+				 enum nl80211_channel_type channel_type)
+{
+	struct ieee80211_local *local = wiphy_priv(wiphy);
+	struct ieee80211_sub_if_data *sdata = NULL;
+
+	if (netdev)
+		sdata = IEEE80211_DEV_TO_SUB_IF(netdev);
+
+	switch (ieee80211_get_channel_mode(local, NULL)) {
+	case CHAN_MODE_HOPPING:
+		return -EBUSY;
+	case CHAN_MODE_FIXED:
+		if (local->oper_channel != chan)
+			return -EBUSY;
+		if (!sdata && local->_oper_channel_type == channel_type)
+			return 0;
+		break;
+	case CHAN_MODE_UNDEFINED:
+		break;
+	}
+
+	if (!ieee80211_set_channel_type(local, sdata, channel_type))
+		return -EBUSY;
+
+	local->oper_channel = chan;
+
+	/* auto-detects changes */
+	ieee80211_hw_config(local, 0);
+
+	return 0;
+}
+
 static int ieee80211_set_probe_resp(struct ieee80211_sub_if_data *sdata,
 				    const u8 *resp, size_t resp_len)
 {
@@ -1676,41 +1711,6 @@ static int ieee80211_set_txq_params(stru
 
 	return 0;
 }
-
-static int ieee80211_set_channel(struct wiphy *wiphy,
-				 struct net_device *netdev,
-				 struct ieee80211_channel *chan,
-				 enum nl80211_channel_type channel_type)
-{
-	struct ieee80211_local *local = wiphy_priv(wiphy);
-	struct ieee80211_sub_if_data *sdata = NULL;
-
-	if (netdev)
-		sdata = IEEE80211_DEV_TO_SUB_IF(netdev);
-
-	switch (ieee80211_get_channel_mode(local, NULL)) {
-	case CHAN_MODE_HOPPING:
-		return -EBUSY;
-	case CHAN_MODE_FIXED:
-		if (local->oper_channel != chan)
-			return -EBUSY;
-		if (!sdata && local->_oper_channel_type == channel_type)
-			return 0;
-		break;
-	case CHAN_MODE_UNDEFINED:
-		break;
-	}
-
-	if (!ieee80211_set_channel_type(local, sdata, channel_type))
-		return -EBUSY;
-
-	local->oper_channel = chan;
-
-	/* auto-detects changes */
-	ieee80211_hw_config(local, 0);
-
-	return 0;
-}
 
 #ifdef CONFIG_PM
 static int ieee80211_suspend(struct wiphy *wiphy,

[PATCH 2/3] cfg80211: simplify cfg80211_can_beacon_sec_chan API

[Johannes Berg]

From: Johannes Berg <johannes.berg@intel.com>

Change cfg80211_can_beacon_sec_chan() to return true
if there is no secondary channel to simplify all the
current users of it. They all check the channel type
before calling the function because it returns false
if there's no secondary channel.

Also actually document the return value.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 include/net/cfg80211.h |    5 ++++-
 net/mac80211/ibss.c    |    3 +--
 net/wireless/chan.c    |   22 ++++++----------------
 3 files changed, 11 insertions(+), 19 deletions(-)

--- a/include/net/cfg80211.h	2012-05-11 10:22:59.000000000 +0200
+++ b/include/net/cfg80211.h	2012-05-11 10:23:50.000000000 +0200
@@ -3359,11 +3359,14 @@ void cfg80211_report_obss_beacon(struct
 				 const u8 *frame, size_t len,
 				 int freq, int sig_dbm, gfp_t gfp);
 
-/*
+/**
  * cfg80211_can_beacon_sec_chan - test if ht40 on extension channel can be used
  * @wiphy: the wiphy
  * @chan: main channel
  * @channel_type: HT mode
+ *
+ * This function returns true if there is no secondary channel or the secondary
+ * channel can be used for beaconing (i.e. is not a radar channel etc.)
  */
 bool cfg80211_can_beacon_sec_chan(struct wiphy *wiphy,
 				  struct ieee80211_channel *chan,
--- a/net/mac80211/ibss.c	2012-05-10 08:54:21.000000000 +0200
+++ b/net/mac80211/ibss.c	2012-05-11 10:24:13.000000000 +0200
@@ -82,8 +82,7 @@ static void __ieee80211_sta_join_ibss(st
 
 	local->oper_channel = chan;
 	channel_type = ifibss->channel_type;
-	if (channel_type > NL80211_CHAN_HT20 &&
-	    !cfg80211_can_beacon_sec_chan(local->hw.wiphy, chan, channel_type))
+	if (!cfg80211_can_beacon_sec_chan(local->hw.wiphy, chan, channel_type))
 		channel_type = NL80211_CHAN_HT20;
 	if (!ieee80211_set_channel_type(local, sdata, channel_type)) {
 		/* can only fail due to HT40+/- mismatch */
--- a/net/wireless/chan.c	2012-05-11 10:22:59.000000000 +0200
+++ b/net/wireless/chan.c	2012-05-11 10:25:12.000000000 +0200
@@ -60,7 +60,7 @@ bool cfg80211_can_beacon_sec_chan(struct
 		diff = -20;
 		break;
 	default:
-		return false;
+		return true;
 	}
 
 	sec_chan = ieee80211_get_channel(wiphy, chan->center_freq + diff);
@@ -107,21 +107,11 @@ int cfg80211_set_freq(struct cfg80211_re
 		     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 (!cfg80211_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;
-		}
+		     wdev->iftype == NL80211_IFTYPE_P2P_GO) &&
+	    !cfg80211_can_beacon_sec_chan(&rdev->wiphy, chan, channel_type)) {
+		printk(KERN_DEBUG
+		       "cfg80211: Secondary channel not allowed to beacon\n");
+		return -EINVAL;
 	}
 
 	result = rdev->ops->set_channel(&rdev->wiphy,

[PATCH 3/3] cfg80211: provide channel to start_ap function

[Johannes Berg]

From: Johannes Berg <johannes.berg@intel.com>

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: Johannes Berg <johannes.berg@intel.com>
---
 drivers/net/wireless/ath/ath6kl/cfg80211.c |   36 +---------------------
 drivers/net/wireless/ath/ath6kl/core.h     |    3 -
 include/linux/nl80211.h                    |    2 +
 include/net/cfg80211.h                     |   12 ++++++-
 net/mac80211/cfg.c                         |    5 +++
 net/wireless/nl80211.c                     |   47 ++++++++++++++++++++++++++++-
 6 files changed, 67 insertions(+), 38 deletions(-)

--- a/include/net/cfg80211.h	2012-05-11 10:23:50.000000000 +0200
+++ b/include/net/cfg80211.h	2012-05-11 10:30:14.000000000 +0200
@@ -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;
--- a/net/wireless/nl80211.c	2012-05-11 10:22:59.000000000 +0200
+++ b/net/wireless/nl80211.c	2012-05-11 10:30:14.000000000 +0200
@@ -1132,6 +1132,9 @@ static bool nl80211_can_set_dev_channel(
 	 * 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 ||
@@ -1166,6 +1169,7 @@ static int __nl80211_set_channel(struct
 				 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;
@@ -1183,7 +1187,25 @@ static int __nl80211_set_channel(struct
 	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);
@@ -2259,6 +2281,29 @@ static int nl80211_start_ap(struct sk_bu
 			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;
--- a/include/linux/nl80211.h	2012-05-11 10:22:59.000000000 +0200
+++ b/include/linux/nl80211.h	2012-05-11 10:30:04.000000000 +0200
@@ -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
--- a/drivers/net/wireless/ath/ath6kl/cfg80211.c	2012-05-11 10:21:59.000000000 +0200
+++ b/drivers/net/wireless/ath/ath6kl/cfg80211.c	2012-05-11 10:30:04.000000000 +0200
@@ -2521,35 +2521,6 @@ static int ath6kl_set_ies(struct ath6kl_
 	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)
 {
@@ -2721,7 +2692,7 @@ static int ath6kl_start_ap(struct wiphy
 	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);
@@ -2745,8 +2716,8 @@ static int ath6kl_start_ap(struct wiphy
 			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;
 
 	/*
@@ -3213,7 +3184,6 @@ static struct cfg80211_ops ath6kl_cfg802
 	.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,
--- a/drivers/net/wireless/ath/ath6kl/core.h	2012-05-11 10:21:59.000000000 +0200
+++ b/drivers/net/wireless/ath/ath6kl/core.h	2012-05-11 10:30:04.000000000 +0200
@@ -543,9 +543,6 @@ 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;
--- a/net/mac80211/cfg.c	2012-05-11 10:22:59.000000000 +0200
+++ b/net/mac80211/cfg.c	2012-05-11 10:30:14.000000000 +0200
@@ -823,6 +823,11 @@ static int ieee80211_start_ap(struct wip
 	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.

Re: [PATCH 3/3] cfg80211: provide channel to start_ap function

[Kalle Valo]

On 05/11/2012 11:34 AM, Johannes Berg wrote:
> From: Johannes Berg <johannes.berg@intel.com>
> 
> 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: Johannes Berg <johannes.berg@intel.com>

For the ath6kl part:

Acked-by: Kalle Valo <kvalo@qca.qualcomm.com>

Kalle

Re: [PATCH 0/3] AP mode channel setting simplification

[John W. Linville]

On Fri, May 11, 2012 at 10:34:13AM +0200, Johannes Berg wrote:
> Ath6kl stores the channel, while mac80211 tries to
> immediately apply it. The latter isn't great for
> multi-channel.
> 
> Change cfg80211 to store the channel, and give it
> to the driver (mac80211, ath6kl, etc.) only in the
> start_ap() function.
> 
> This simplifies ath6kl a lot, and while it doesn't
> make a difference to mac80211 today I think it'll
> make it simpler to implement multi-channel.
> 
> johannes

I had some trouble with applying at least 1/3, so I skipped this
batch as well.

John
-- 
John W. Linville		Someday the world will need a hero, and you
linville@tuxdriver.com			might be all we have.  Be ready.