cfg80211: Dynamic channel bandwidth changes in AP mode

This extends NL80211_CMD_SET_CHANNEL to allow dynamic channel bandwidth
changes in AP mode (including P2P GO) during a lifetime of the BSS. This
can be used to implement, e.g., HT 20/40 MHz co-existence rules on the
2.4 GHz band.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index c98cf08..7eae46c 100644 (file)
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -2290,6 +2290,10 @@ struct cfg80211_qos_map {
  * @channel_switch: initiate channel-switch procedure (with CSA)
  *
  * @set_qos_map: Set QoS mapping information to the driver
+ *
+ * @set_ap_chanwidth: Set the AP (including P2P GO) mode channel width for the
+ *     given interface This is used e.g. for dynamic HT 20/40 MHz channel width
+ *     changes during the lifetime of the BSS.
  */
 struct cfg80211_ops {
        int     (*suspend)(struct wiphy *wiphy, struct cfg80211_wowlan *wow);
@@ -2533,9 +2537,13 @@ struct cfg80211_ops {
        int     (*channel_switch)(struct wiphy *wiphy,
                                  struct net_device *dev,
                                  struct cfg80211_csa_settings *params);
+
        int     (*set_qos_map)(struct wiphy *wiphy,
                               struct net_device *dev,
                               struct cfg80211_qos_map *qos_map);
+
+       int     (*set_ap_chanwidth)(struct wiphy *wiphy, struct net_device *dev,
+                                   struct cfg80211_chan_def *chandef);
 };
 
 /*

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 0592032..406010d 100644 (file)
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -3929,6 +3929,9 @@ enum nl80211_ap_sme_features {
  *     interface. An active monitor interface behaves like a normal monitor
  *     interface, but gets added to the driver. It ensures that incoming
  *     unicast packets directed at the configured interface address get ACKed.
+ * @NL80211_FEATURE_AP_MODE_CHAN_WIDTH_CHANGE: This driver supports dynamic
+ *     channel bandwidth change (e.g., HT 20 <-> 40 MHz channel) during the
+ *     lifetime of a BSS.
  */
 enum nl80211_feature_flags {
        NL80211_FEATURE_SK_TX_STATUS                    = 1 << 0,
@@ -3949,6 +3952,7 @@ enum nl80211_feature_flags {
        NL80211_FEATURE_FULL_AP_CLIENT_STATE            = 1 << 15,
        NL80211_FEATURE_USERSPACE_MPM                   = 1 << 16,
        NL80211_FEATURE_ACTIVE_MONITOR                  = 1 << 17,
+       NL80211_FEATURE_AP_MODE_CHAN_WIDTH_CHANGE       = 1 << 18,
 };
 
 /**

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index ca75f60..0f1b18f 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -1928,18 +1928,20 @@ static int nl80211_parse_chandef(struct cfg80211_registered_device *rdev,
 }
 
 static int __nl80211_set_channel(struct cfg80211_registered_device *rdev,
-                                struct wireless_dev *wdev,
+                                struct net_device *dev,
                                 struct genl_info *info)
 {
        struct cfg80211_chan_def chandef;
        int result;
        enum nl80211_iftype iftype = NL80211_IFTYPE_MONITOR;
+       struct wireless_dev *wdev = NULL;
 
-       if (wdev)
-               iftype = wdev->iftype;
-
+       if (dev)
+               wdev = dev->ieee80211_ptr;
        if (!nl80211_can_set_dev_channel(wdev))
                return -EOPNOTSUPP;
+       if (wdev)
+               iftype = wdev->iftype;
 
        result = nl80211_parse_chandef(rdev, info, &chandef);
        if (result)
@@ -1948,14 +1950,27 @@ static int __nl80211_set_channel(struct cfg80211_registered_device *rdev,
        switch (iftype) {
        case NL80211_IFTYPE_AP:
        case NL80211_IFTYPE_P2P_GO:
-               if (wdev->beacon_interval) {
-                       result = -EBUSY;
-                       break;
-               }
                if (!cfg80211_reg_can_beacon(&rdev->wiphy, &chandef, iftype)) {
                        result = -EINVAL;
                        break;
                }
+               if (wdev->beacon_interval) {
+                       if (!dev || !rdev->ops->set_ap_chanwidth ||
+                           !(rdev->wiphy.features &
+                             NL80211_FEATURE_AP_MODE_CHAN_WIDTH_CHANGE)) {
+                               result = -EBUSY;
+                               break;
+                       }
+
+                       /* Only allow dynamic channel width changes */
+                       if (chandef.chan != wdev->preset_chandef.chan) {
+                               result = -EBUSY;
+                               break;
+                       }
+                       result = rdev_set_ap_chanwidth(rdev, dev, &chandef);
+                       if (result)
+                               break;
+               }
                wdev->preset_chandef = chandef;
                result = 0;
                break;
@@ -1977,7 +1992,7 @@ static int nl80211_set_channel(struct sk_buff *skb, struct genl_info *info)
        struct cfg80211_registered_device *rdev = info->user_ptr[0];
        struct net_device *netdev = info->user_ptr[1];
 
-       return __nl80211_set_channel(rdev, netdev->ieee80211_ptr, info);
+       return __nl80211_set_channel(rdev, netdev, info);
 }
 
 static int nl80211_set_wds_peer(struct sk_buff *skb, struct genl_info *info)
@@ -2099,9 +2114,10 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
        }
 
        if (info->attrs[NL80211_ATTR_WIPHY_FREQ]) {
-               result = __nl80211_set_channel(rdev,
-                               nl80211_can_set_dev_channel(wdev) ? wdev : NULL,
-                               info);
+               result = __nl80211_set_channel(
+                       rdev,
+                       nl80211_can_set_dev_channel(wdev) ? netdev : NULL,
+                       info);
                if (result)
                        return result;
        }

diff --git a/net/wireless/rdev-ops.h b/net/wireless/rdev-ops.h
index 74d97d3..00cdf73 100644 (file)
--- a/net/wireless/rdev-ops.h
+++ b/net/wireless/rdev-ops.h
@@ -950,4 +950,17 @@ static inline int rdev_set_qos_map(struct cfg80211_registered_device *rdev,
        return ret;
 }
 
+static inline int
+rdev_set_ap_chanwidth(struct cfg80211_registered_device *rdev,
+                     struct net_device *dev, struct cfg80211_chan_def *chandef)
+{
+       int ret;
+
+       trace_rdev_set_ap_chanwidth(&rdev->wiphy, dev, chandef);
+       ret = rdev->ops->set_ap_chanwidth(&rdev->wiphy, dev, chandef);
+       trace_rdev_return_int(&rdev->wiphy, ret);
+
+       return ret;
+}
+
 #endif /* __CFG80211_RDEV_OPS */

diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index 47b499f..f3c13ff 100644 (file)
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -1919,6 +1919,24 @@ TRACE_EVENT(rdev_set_qos_map,
                  WIPHY_PR_ARG, NETDEV_PR_ARG, __entry->num_des)
 );
 
+TRACE_EVENT(rdev_set_ap_chanwidth,
+       TP_PROTO(struct wiphy *wiphy, struct net_device *netdev,
+                struct cfg80211_chan_def *chandef),
+       TP_ARGS(wiphy, netdev, chandef),
+       TP_STRUCT__entry(
+               WIPHY_ENTRY
+               NETDEV_ENTRY
+               CHAN_DEF_ENTRY
+       ),
+       TP_fast_assign(
+               WIPHY_ASSIGN;
+               NETDEV_ASSIGN;
+               CHAN_DEF_ASSIGN(chandef);
+       ),
+       TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", " CHAN_DEF_PR_FMT,
+                 WIPHY_PR_ARG, NETDEV_PR_ARG, CHAN_DEF_PR_ARG)
+);
+
 /*************************************************************
  *          cfg80211 exported functions traces              *
  *************************************************************/