cfg80211: add channel switch started notification

Add a new NL80211_CH_SWITCH_STARTED_NOTIFY message that can be sent to
the userspace when a channel switch process has started.  This allows
userspace to take action, for instance, by requesting other interfaces
to switch channel as necessary.

This patch introduces a function that allows the drivers to send this
notification.  It should be used when the driver starts processing a
channel switch initiated by a remote device (eg. when a STA receives a
CSA from the AP) and when it successfully starts a userspace-triggered
channel switch (eg. when hostapd triggers a channel swith in the AP).

Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 5c3acd07acd982be8b38097d91e1908003aea66c..220d5f5f1aca694c48ec33299ef628eee328eb74 100644 (file)
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -4719,6 +4719,20 @@ bool cfg80211_reg_can_beacon(struct wiphy *wiphy,
 void cfg80211_ch_switch_notify(struct net_device *dev,
                               struct cfg80211_chan_def *chandef);
 
+/*
+ * cfg80211_ch_switch_started_notify - notify channel switch start
+ * @dev: the device on which the channel switch started
+ * @chandef: the future channel definition
+ * @count: the number of TBTTs until the channel switch happens
+ *
+ * Inform the userspace about the channel switch that has just
+ * started, so that it can take appropriate actions (eg. starting
+ * channel switch on other vifs), if necessary.
+ */
+void cfg80211_ch_switch_started_notify(struct net_device *dev,
+                                      struct cfg80211_chan_def *chandef,
+                                      u8 count);
+
 /**
  * ieee80211_operating_class_to_band - convert operating class to band
  *

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 9b3025e4377a6e1ab9663341ee433afbd2f1d1c6..3541634333522f1b0312deab634c33e1ea570923 100644 (file)
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -645,6 +645,15 @@
  *     %NL80211_ATTR_IFINDEX is now on %NL80211_ATTR_WIPHY_FREQ and the
  *     attributes determining channel width.
  *
+ * @NL80211_CMD_CH_SWITCH_STARTED_NOTIFY: Notify that a channel switch
+ *     has been started on an interface, regardless of the initiator
+ *     (ie. whether it was requested from a remote device or
+ *     initiated on our own).  It indicates that
+ *     %NL80211_ATTR_IFINDEX will be on %NL80211_ATTR_WIPHY_FREQ
+ *     after %NL80211_ATTR_CH_SWITCH_COUNT TBTT's.  The userspace may
+ *     decide to react to this indication by requesting other
+ *     interfaces to change channel as well.
+ *
  * @NL80211_CMD_START_P2P_DEVICE: Start the given P2P Device, identified by
  *     its %NL80211_ATTR_WDEV identifier. It must have been created with
  *     %NL80211_CMD_NEW_INTERFACE previously. After it has been started, the
@@ -930,6 +939,8 @@ enum nl80211_commands {
        NL80211_CMD_JOIN_OCB,
        NL80211_CMD_LEAVE_OCB,
 
+       NL80211_CMD_CH_SWITCH_STARTED_NOTIFY,
+
        /* add new commands above here */
 
        /* used to define NL80211_CMD_MAX below */

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 24549cbe0b54edb38255b0beb058692de0acf837..24fd2925b2814aec91b0bd2531d88d2b88b7fd19 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -11653,7 +11653,9 @@ EXPORT_SYMBOL(cfg80211_pmksa_candidate_notify);
 static void nl80211_ch_switch_notify(struct cfg80211_registered_device *rdev,
                                     struct net_device *netdev,
                                     struct cfg80211_chan_def *chandef,
-                                    gfp_t gfp)
+                                    gfp_t gfp,
+                                    enum nl80211_commands notif,
+                                    u8 count)
 {
        struct sk_buff *msg;
        void *hdr;
@@ -11662,7 +11664,7 @@ static void nl80211_ch_switch_notify(struct cfg80211_registered_device *rdev,
        if (!msg)
                return;
 
-       hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_CH_SWITCH_NOTIFY);
+       hdr = nl80211hdr_put(msg, 0, 0, 0, notif);
        if (!hdr) {
                nlmsg_free(msg);
                return;
@@ -11674,6 +11676,10 @@ static void nl80211_ch_switch_notify(struct cfg80211_registered_device *rdev,
        if (nl80211_send_chandef(msg, chandef))
                goto nla_put_failure;
 
+       if ((notif == NL80211_CMD_CH_SWITCH_STARTED_NOTIFY) &&
+           (nla_put_u32(msg, NL80211_ATTR_CH_SWITCH_COUNT, count)))
+                       goto nla_put_failure;
+
        genlmsg_end(msg, hdr);
 
        genlmsg_multicast_netns(&nl80211_fam, wiphy_net(&rdev->wiphy), msg, 0,
@@ -11704,10 +11710,26 @@ void cfg80211_ch_switch_notify(struct net_device *dev,
 
        wdev->chandef = *chandef;
        wdev->preset_chandef = *chandef;
-       nl80211_ch_switch_notify(rdev, dev, chandef, GFP_KERNEL);
+       nl80211_ch_switch_notify(rdev, dev, chandef, GFP_KERNEL,
+                                NL80211_CMD_CH_SWITCH_NOTIFY, 0);
 }
 EXPORT_SYMBOL(cfg80211_ch_switch_notify);
 
+void cfg80211_ch_switch_started_notify(struct net_device *dev,
+                                      struct cfg80211_chan_def *chandef,
+                                      u8 count)
+{
+       struct wireless_dev *wdev = dev->ieee80211_ptr;
+       struct wiphy *wiphy = wdev->wiphy;
+       struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
+
+       trace_cfg80211_ch_switch_started_notify(dev, chandef);
+
+       nl80211_ch_switch_notify(rdev, dev, chandef, GFP_KERNEL,
+                                NL80211_CMD_CH_SWITCH_STARTED_NOTIFY, count);
+}
+EXPORT_SYMBOL(cfg80211_ch_switch_started_notify);
+
 void cfg80211_cqm_txe_notify(struct net_device *dev,
                             const u8 *peer, u32 num_packets,
                             u32 rate, u32 intvl, gfp_t gfp)

diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index 277a85df910eef03fe9c0354addf28fe3f2e4adc..6e25370d3ce7974a9e9f1bcc7cc7125829ecc172 100644 (file)
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -2355,6 +2355,22 @@ TRACE_EVENT(cfg80211_ch_switch_notify,
                  NETDEV_PR_ARG, CHAN_DEF_PR_ARG)
 );
 
+TRACE_EVENT(cfg80211_ch_switch_started_notify,
+       TP_PROTO(struct net_device *netdev,
+                struct cfg80211_chan_def *chandef),
+       TP_ARGS(netdev, chandef),
+       TP_STRUCT__entry(
+               NETDEV_ENTRY
+               CHAN_DEF_ENTRY
+       ),
+       TP_fast_assign(
+               NETDEV_ASSIGN;
+               CHAN_DEF_ASSIGN(chandef);
+       ),
+       TP_printk(NETDEV_PR_FMT ", " CHAN_DEF_PR_FMT,
+                 NETDEV_PR_ARG, CHAN_DEF_PR_ARG)
+);
+
 TRACE_EVENT(cfg80211_radar_event,
        TP_PROTO(struct wiphy *wiphy, struct cfg80211_chan_def *chandef),
        TP_ARGS(wiphy, chandef),