11 files changed, 570 insertions, 17 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 7e6569e1f16f..ee11a3db730b 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -114,6 +114,9 @@ enum ieee80211_channel_flags {
 #define IEEE80211_CHAN_NO_HT40 \
         (IEEE80211_CHAN_NO_HT40PLUS | IEEE80211_CHAN_NO_HT40MINUS)
 
+#define IEEE80211_DFS_MIN_CAC_TIME_MS           60000
+#define IEEE80211_DFS_MIN_NOP_TIME_MS           (30 * 60 * 1000)
+
 /**
  * struct ieee80211_channel - channel definition
  *
@@ -134,6 +137,9 @@ enum ieee80211_channel_flags {
  *      to enable this, this is useful only on 5 GHz band.
  * @orig_mag: internal use
  * @orig_mpwr: internal use
+ * @dfs_state: current state of this channel. Only relevant if radar is required
+ *      on this channel.
+ * @dfs_state_entered: timestamp (jiffies) when the dfs state was entered.
  */
 struct ieee80211_channel {
         enum ieee80211_band band;
@@ -146,6 +152,8 @@ struct ieee80211_channel {
         bool beacon_found;
         u32 orig_flags;
         int orig_mag, orig_mpwr;
+        enum nl80211_dfs_state dfs_state;
+        unsigned long dfs_state_entered;
 };
 
 /**
@@ -569,6 +577,7 @@ struct cfg80211_acl_data {
  * @p2p_opp_ps: P2P opportunistic PS
  * @acl: ACL configuration used by the drivers which has support for
  *      MAC address based access control
+ * @radar_required: set if radar detection is required
  */
 struct cfg80211_ap_settings {
         struct cfg80211_chan_def chandef;
@@ -586,6 +595,7 @@ struct cfg80211_ap_settings {
         u8 p2p_ctwindow;
         bool p2p_opp_ps;
         const struct cfg80211_acl_data *acl;
+        bool radar_required;
 };
 
 /**
@@ -1909,6 +1919,8 @@ struct cfg80211_gtk_rekey_data {
  *      this new list replaces the existing one. Driver has to clear its ACL
  *      when number of MAC addresses entries is passed as 0. Drivers which
  *      advertise the support for MAC based ACL have to implement this callback.
+ *
+ * @start_radar_detection: Start radar detection in the driver.
  */
 struct cfg80211_ops {
         int     (*suspend)(struct wiphy *wiphy, struct cfg80211_wowlan *wow);
@@ -2132,6 +2144,10 @@ struct cfg80211_ops {
 
         int     (*set_mac_acl)(struct wiphy *wiphy, struct net_device *dev,
                                const struct cfg80211_acl_data *params);
+
+        int     (*start_radar_detection)(struct wiphy *wiphy,
+                                         struct net_device *dev,
+                                         struct cfg80211_chan_def *chandef);
 };
 
 /*
@@ -2715,6 +2731,8 @@ struct cfg80211_cached_keys;
  *      beacons, 0 when not valid
  * @address: The address for this device, valid only if @netdev is %NULL
  * @p2p_started: true if this is a P2P Device that has been started
+ * @cac_started: true if DFS channel availability check has been started
+ * @cac_start_time: timestamp (jiffies) when the dfs state was entered.
  */
 struct wireless_dev {
         struct wiphy *wiphy;
@@ -2766,6 +2784,9 @@ struct wireless_dev {
 
         u32 ap_unexpected_nlportid;
 
+        bool cac_started;
+        unsigned long cac_start_time;
+
 #ifdef CONFIG_CFG80211_WEXT
         /* wext data */
         struct {
@@ -3755,6 +3776,31 @@ void cfg80211_cqm_rssi_notify(struct net_device *dev,
                               gfp_t gfp);
 
 /**
+ * cfg80211_radar_event - radar detection event
+ * @wiphy: the wiphy
+ * @chandef: chandef for the current channel
+ * @gfp: context flags
+ *
+ * This function is called when a radar is detected on the current chanenl.
+ */
+void cfg80211_radar_event(struct wiphy *wiphy,
+                          struct cfg80211_chan_def *chandef, gfp_t gfp);
+
+/**
+ * cfg80211_cac_event - Channel availability check (CAC) event
+ * @netdev: network device
+ * @event: type of event
+ * @gfp: context flags
+ *
+ * This function is called when a Channel availability check (CAC) is finished
+ * or aborted. This must be called to notify the completion of a CAC process,
+ * also by full-MAC drivers.
+ */
+void cfg80211_cac_event(struct net_device *netdev,
+                        enum nl80211_radar_event event, gfp_t gfp);
+
+
+/**
  * cfg80211_cqm_pktloss_notify - notify userspace about packetloss to peer
  * @dev: network device
  * @peer: peer's MAC address
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 5309b34930ea..90b7af86f392 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -603,6 +603,14 @@
  *      command is used in AP/P2P GO mode. Driver has to make sure to clear its
  *      ACL list during %NL80211_CMD_STOP_AP.
  *
+ * @NL80211_CMD_RADAR_DETECT: Start a Channel availability check (CAC). Once
+ *      a radar is detected or the channel availability scan (CAC) has finished
+ *      or was aborted, or a radar was detected, usermode will be notified with
+ *      this event. This command is also used to notify userspace about radars
+ *      while operating on this channel.
+ *      %NL80211_ATTR_RADAR_EVENT is used to inform about the type of the
+ *      event.
+ *
  * @NL80211_CMD_MAX: highest used command number
  * @__NL80211_CMD_AFTER_LAST: internal use
  */
@@ -755,6 +763,8 @@ enum nl80211_commands {
 
         NL80211_CMD_SET_MAC_ACL,
 
+        NL80211_CMD_RADAR_DETECT,
+
         /* add new commands above here */
 
         /* used to define NL80211_CMD_MAX below */
@@ -1342,6 +1352,9 @@ enum nl80211_commands {
  *      number of MAC addresses that a device can support for MAC
  *      ACL.
  *
+ * @NL80211_ATTR_RADAR_EVENT: Type of radar event for notification to userspace,
+ *      contains a value of enum nl80211_radar_event (u32).
+ *
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
  */
@@ -1620,6 +1633,8 @@ enum nl80211_attrs {
 
         NL80211_ATTR_MAC_ACL_MAX,
 
+        NL80211_ATTR_RADAR_EVENT,
+
         /* add attributes here, update the policy in nl80211.c */
 
         __NL80211_ATTR_AFTER_LAST,
@@ -2022,6 +2037,10 @@ enum nl80211_band_attr {
  *      on this channel in current regulatory domain.
  * @NL80211_FREQUENCY_ATTR_MAX_TX_POWER: Maximum transmission power in mBm
  *      (100 * dBm).
+ * @NL80211_FREQUENCY_ATTR_DFS_STATE: current state for DFS
+ *      (enum nl80211_dfs_state)
+ * @NL80211_FREQUENCY_ATTR_DFS_TIME: time in miliseconds for how long
+ *      this channel is in this DFS state.
  * @NL80211_FREQUENCY_ATTR_MAX: highest frequency attribute number
  *      currently defined
  * @__NL80211_FREQUENCY_ATTR_AFTER_LAST: internal use
@@ -2034,6 +2053,8 @@ enum nl80211_frequency_attr {
         NL80211_FREQUENCY_ATTR_NO_IBSS,
         NL80211_FREQUENCY_ATTR_RADAR,
         NL80211_FREQUENCY_ATTR_MAX_TX_POWER,
+        NL80211_FREQUENCY_ATTR_DFS_STATE,
+        NL80211_FREQUENCY_ATTR_DFS_TIME,
 
         /* keep last */
         __NL80211_FREQUENCY_ATTR_AFTER_LAST,
@@ -3489,4 +3510,44 @@ enum nl80211_acl_policy {
         NL80211_ACL_POLICY_DENY_UNLESS_LISTED,
 };
 
+/**
+ * enum nl80211_radar_event - type of radar event for DFS operation
+ *
+ * Type of event to be used with NL80211_ATTR_RADAR_EVENT to inform userspace
+ * about detected radars or success of the channel available check (CAC)
+ *
+ * @NL80211_RADAR_DETECTED: A radar pattern has been detected. The channel is
+ *      now unusable.
+ * @NL80211_RADAR_CAC_FINISHED: Channel Availability Check has been finished,
+ *      the channel is now available.
+ * @NL80211_RADAR_CAC_ABORTED: Channel Availability Check has been aborted, no
+ *      change to the channel status.
+ * @NL80211_RADAR_NOP_FINISHED: The Non-Occupancy Period for this channel is
+ *      over, channel becomes usable.
+ */
+enum nl80211_radar_event {
+        NL80211_RADAR_DETECTED,
+        NL80211_RADAR_CAC_FINISHED,
+        NL80211_RADAR_CAC_ABORTED,
+        NL80211_RADAR_NOP_FINISHED,
+};
+
+/**
+ * enum nl80211_dfs_state - DFS states for channels
+ *
+ * Channel states used by the DFS code.
+ *
+ * @IEEE80211_DFS_USABLE: The channel can be used, but channel availability
+ *      check (CAC) must be performed before using it for AP or IBSS.
+ * @IEEE80211_DFS_UNAVAILABLE: A radar has been detected on this channel, it
+ *      is therefore marked as not available.
+ * @IEEE80211_DFS_AVAILABLE: The channel has been CAC checked and is available.
+ */
+
+enum nl80211_dfs_state {
+        NL80211_DFS_USABLE,
+        NL80211_DFS_UNAVAILABLE,
+        NL80211_DFS_AVAILABLE,
+};
+
 #endif /* __LINUX_NL80211_H */
diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index 396373f3ec26..810c23cfb894 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -147,6 +147,32 @@ static void chandef_primary_freqs(const struct cfg80211_chan_def *c,
         }
 }
 
+static int cfg80211_chandef_get_width(const struct cfg80211_chan_def *c)
+{
+        int width;
+
+        switch (c->width) {
+        case NL80211_CHAN_WIDTH_20:
+        case NL80211_CHAN_WIDTH_20_NOHT:
+                width = 20;
+                break;
+        case NL80211_CHAN_WIDTH_40:
+                width = 40;
+                break;
+        case NL80211_CHAN_WIDTH_80P80:
+        case NL80211_CHAN_WIDTH_80:
+                width = 80;
+                break;
+        case NL80211_CHAN_WIDTH_160:
+                width = 160;
+                break;
+        default:
+                WARN_ON_ONCE(1);
+                return -1;
+        }
+        return width;
+}
+
 const struct cfg80211_chan_def *
 cfg80211_chandef_compatible(const struct cfg80211_chan_def *c1,
                             const struct cfg80211_chan_def *c2)
@@ -192,6 +218,93 @@ cfg80211_chandef_compatible(const struct cfg80211_chan_def *c1,
 }
 EXPORT_SYMBOL(cfg80211_chandef_compatible);
 
+static void cfg80211_set_chans_dfs_state(struct wiphy *wiphy, u32 center_freq,
+                                         u32 bandwidth,
+                                         enum nl80211_dfs_state dfs_state)
+{
+        struct ieee80211_channel *c;
+        u32 freq;
+
+        for (freq = center_freq - bandwidth/2 + 10;
+             freq <= center_freq + bandwidth/2 - 10;
+             freq += 20) {
+                c = ieee80211_get_channel(wiphy, freq);
+                if (!c || !(c->flags & IEEE80211_CHAN_RADAR))
+                        continue;
+
+                c->dfs_state = dfs_state;
+                c->dfs_state_entered = jiffies;
+        }
+}
+
+void cfg80211_set_dfs_state(struct wiphy *wiphy,
+                            const struct cfg80211_chan_def *chandef,
+                            enum nl80211_dfs_state dfs_state)
+{
+        int width;
+
+        if (WARN_ON(!cfg80211_chandef_valid(chandef)))
+                return;
+
+        width = cfg80211_chandef_get_width(chandef);
+        if (width < 0)
+                return;
+
+        cfg80211_set_chans_dfs_state(wiphy, chandef->center_freq1,
+                                     width, dfs_state);
+
+        if (!chandef->center_freq2)
+                return;
+        cfg80211_set_chans_dfs_state(wiphy, chandef->center_freq2,
+                                     width, dfs_state);
+}
+
+static int cfg80211_get_chans_dfs_required(struct wiphy *wiphy,
+                                            u32 center_freq,
+                                            u32 bandwidth)
+{
+        struct ieee80211_channel *c;
+        u32 freq;
+
+        for (freq = center_freq - bandwidth/2 + 10;
+             freq <= center_freq + bandwidth/2 - 10;
+             freq += 20) {
+                c = ieee80211_get_channel(wiphy, freq);
+                if (!c)
+                        return -EINVAL;
+
+                if (c->flags & IEEE80211_CHAN_RADAR)
+                        return 1;
+        }
+        return 0;
+}
+
+
+int cfg80211_chandef_dfs_required(struct wiphy *wiphy,
+                                  const struct cfg80211_chan_def *chandef)
+{
+        int width;
+        int r;
+
+        if (WARN_ON(!cfg80211_chandef_valid(chandef)))
+                return -EINVAL;
+
+        width = cfg80211_chandef_get_width(chandef);
+        if (width < 0)
+                return -EINVAL;
+
+        r = cfg80211_get_chans_dfs_required(wiphy, chandef->center_freq1,
+                                            width);
+        if (r)
+                return r;
+
+        if (!chandef->center_freq2)
+                return 0;
+
+        return cfg80211_get_chans_dfs_required(wiphy, chandef->center_freq2,
+                                               width);
+}
+
 static bool cfg80211_secondary_chans_ok(struct wiphy *wiphy,
                                         u32 center_freq, u32 bandwidth,
                                         u32 prohibited_flags)
@@ -203,7 +316,16 @@ static bool cfg80211_secondary_chans_ok(struct wiphy *wiphy,
              freq <= center_freq + bandwidth/2 - 10;
              freq += 20) {
                 c = ieee80211_get_channel(wiphy, freq);
-                if (!c || c->flags & prohibited_flags)
+                if (!c)
+                        return false;
+
+                /* check for radar flags */
+                if ((prohibited_flags & c->flags & IEEE80211_CHAN_RADAR) &&
+                    (c->dfs_state != NL80211_DFS_AVAILABLE))
+                        return false;
+
+                /* check for the other flags */
+                if (c->flags & prohibited_flags & ~IEEE80211_CHAN_RADAR)
                         return false;
         }
 
@@ -344,7 +466,10 @@ cfg80211_get_chan_state(struct wireless_dev *wdev,
                 break;
         case NL80211_IFTYPE_AP:
         case NL80211_IFTYPE_P2P_GO:
-                if (wdev->beacon_interval) {
+                if (wdev->cac_started) {
+                        *chan = wdev->channel;
+                        *chanmode = CHAN_MODE_SHARED;
+                } else if (wdev->beacon_interval) {
                         *chan = wdev->channel;
                         *chanmode = CHAN_MODE_SHARED;
                 }
diff --git a/net/wireless/core.c b/net/wireless/core.c
index f0a1bbe95cff..922002105062 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -324,6 +324,8 @@ struct wiphy *wiphy_new(const struct cfg80211_ops *ops, int sizeof_priv)
         INIT_LIST_HEAD(&rdev->bss_list);
         INIT_WORK(&rdev->scan_done_wk, __cfg80211_scan_done);
         INIT_WORK(&rdev->sched_scan_results_wk, __cfg80211_sched_scan_results);
+        INIT_DELAYED_WORK(&rdev->dfs_update_channels_wk,
+                          cfg80211_dfs_channels_update_work);
 #ifdef CONFIG_CFG80211_WEXT
         rdev->wiphy.wext = &cfg80211_wext_handler;
 #endif
@@ -695,6 +697,7 @@ void wiphy_unregister(struct wiphy *wiphy)
         flush_work(&rdev->scan_done_wk);
         cancel_work_sync(&rdev->conn_work);
         flush_work(&rdev->event_work);
+        cancel_delayed_work_sync(&rdev->dfs_update_channels_wk);
 
         if (rdev->wowlan && rdev->ops->set_wakeup)
                 rdev_set_wakeup(rdev, false);
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 949c9573d8d7..3aec0e429d8a 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -86,6 +86,8 @@ struct cfg80211_registered_device {
 
         struct cfg80211_wowlan *wowlan;
 
+        struct delayed_work dfs_update_channels_wk;
+
         /* must be last because of the way we do wiphy_priv(),
          * and it should at least be aligned to NETDEV_ALIGN */
         struct wiphy wiphy __aligned(NETDEV_ALIGN);
@@ -431,6 +433,22 @@ int cfg80211_can_use_iftype_chan(struct cfg80211_registered_device *rdev,
                                  enum cfg80211_chan_mode chanmode,
                                  u8 radar_detect);
 
+/**
+ * cfg80211_chandef_dfs_required - checks if radar detection is required
+ * @wiphy: the wiphy to validate against
+ * @chandef: the channel definition to check
+ * Return: 1 if radar detection is required, 0 if it is not, < 0 on error
+ */
+int cfg80211_chandef_dfs_required(struct wiphy *wiphy,
+                                  const struct cfg80211_chan_def *c);
+
+void cfg80211_set_dfs_state(struct wiphy *wiphy,
+                            const struct cfg80211_chan_def *chandef,
+                            enum nl80211_dfs_state dfs_state);
+
+void cfg80211_dfs_channels_update_work(struct work_struct *work);
+
+
 static inline int
 cfg80211_can_change_interface(struct cfg80211_registered_device *rdev,
                               struct wireless_dev *wdev,
@@ -457,6 +475,16 @@ cfg80211_can_use_chan(struct cfg80211_registered_device *rdev,
                                             chan, chanmode, 0);
 }
 
+static inline unsigned int elapsed_jiffies_msecs(unsigned long start)
+{
+        unsigned long end = jiffies;
+
+        if (end >= start)
+                return jiffies_to_msecs(end - start);
+
+        return jiffies_to_msecs(end + (MAX_JIFFY_OFFSET - start) + 1);
+}
+
 void
 cfg80211_get_chan_state(struct wireless_dev *wdev,
                         struct ieee80211_channel **chan,
diff --git a/net/wireless/mlme.c b/net/wireless/mlme.c
index 8e6920728c43..caddca35d686 100644
--- a/net/wireless/mlme.c
+++ b/net/wireless/mlme.c
@@ -987,3 +987,123 @@ void cfg80211_pmksa_candidate_notify(struct net_device *dev, int index,
         nl80211_pmksa_candidate_notify(rdev, dev, index, bssid, preauth, gfp);
 }
 EXPORT_SYMBOL(cfg80211_pmksa_candidate_notify);
+
+void cfg80211_dfs_channels_update_work(struct work_struct *work)
+{
+        struct delayed_work *delayed_work;
+        struct cfg80211_registered_device *rdev;
+        struct cfg80211_chan_def chandef;
+        struct ieee80211_supported_band *sband;
+        struct ieee80211_channel *c;
+        struct wiphy *wiphy;
+        bool check_again = false;
+        unsigned long timeout, next_time = 0;
+        int bandid, i;
+
+        delayed_work = container_of(work, struct delayed_work, work);
+        rdev = container_of(delayed_work, struct cfg80211_registered_device,
+                            dfs_update_channels_wk);
+        wiphy = &rdev->wiphy;
+
+        mutex_lock(&cfg80211_mutex);
+        for (bandid = 0; bandid < IEEE80211_NUM_BANDS; bandid++) {
+                sband = wiphy->bands[bandid];
+                if (!sband)
+                        continue;
+
+                for (i = 0; i < sband->n_channels; i++) {
+                        c = &sband->channels[i];
+
+                        if (c->dfs_state != NL80211_DFS_UNAVAILABLE)
+                                continue;
+
+                        timeout = c->dfs_state_entered +
+                                  IEEE80211_DFS_MIN_NOP_TIME_MS;
+
+                        if (time_after_eq(jiffies, timeout)) {
+                                c->dfs_state = NL80211_DFS_USABLE;
+                                cfg80211_chandef_create(&chandef, c,
+                                                        NL80211_CHAN_NO_HT);
+
+                                nl80211_radar_notify(rdev, &chandef,
+                                                     NL80211_RADAR_NOP_FINISHED,
+                                                     NULL, GFP_ATOMIC);
+                                continue;
+                        }
+
+                        if (!check_again)
+                                next_time = timeout - jiffies;
+                        else
+                                next_time = min(next_time, timeout - jiffies);
+                        check_again = true;
+                }
+        }
+        mutex_unlock(&cfg80211_mutex);
+
+        /* reschedule if there are other channels waiting to be cleared again */
+        if (check_again)
+                queue_delayed_work(cfg80211_wq, &rdev->dfs_update_channels_wk,
+                                   next_time);
+}
+
+
+void cfg80211_radar_event(struct wiphy *wiphy,
+                          struct cfg80211_chan_def *chandef,
+                          gfp_t gfp)
+{
+        struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);
+        unsigned long timeout;
+
+        trace_cfg80211_radar_event(wiphy, chandef);
+
+        /* only set the chandef supplied channel to unavailable, in
+         * case the radar is detected on only one of multiple channels
+         * spanned by the chandef.
+         */
+        cfg80211_set_dfs_state(wiphy, chandef, NL80211_DFS_UNAVAILABLE);
+
+        timeout = msecs_to_jiffies(IEEE80211_DFS_MIN_NOP_TIME_MS);
+        queue_delayed_work(cfg80211_wq, &rdev->dfs_update_channels_wk,
+                           timeout);
+
+        nl80211_radar_notify(rdev, chandef, NL80211_RADAR_DETECTED, NULL, gfp);
+}
+EXPORT_SYMBOL(cfg80211_radar_event);
+
+void cfg80211_cac_event(struct net_device *netdev,
+                        enum nl80211_radar_event event, gfp_t gfp)
+{
+        struct wireless_dev *wdev = netdev->ieee80211_ptr;
+        struct wiphy *wiphy = wdev->wiphy;
+        struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);
+        struct cfg80211_chan_def chandef;
+        unsigned long timeout;
+
+        trace_cfg80211_cac_event(netdev, event);
+
+        if (WARN_ON(!wdev->cac_started))
+                return;
+
+        if (WARN_ON(!wdev->channel))
+                return;
+
+        cfg80211_chandef_create(&chandef, wdev->channel, NL80211_CHAN_NO_HT);
+
+        switch (event) {
+        case NL80211_RADAR_CAC_FINISHED:
+                timeout = wdev->cac_start_time +
+                          msecs_to_jiffies(IEEE80211_DFS_MIN_CAC_TIME_MS);
+                WARN_ON(!time_after_eq(jiffies, timeout));
+                cfg80211_set_dfs_state(wiphy, &chandef, NL80211_DFS_AVAILABLE);
+                break;
+        case NL80211_RADAR_CAC_ABORTED:
+                break;
+        default:
+                WARN_ON(1);
+                return;
+        }
+        wdev->cac_started = false;
+
+        nl80211_radar_notify(rdev, &chandef, event, netdev, gfp);
+}
+EXPORT_SYMBOL(cfg80211_cac_event);
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index d29a461b4981..c1e18ccf4049 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -552,9 +552,16 @@ static int nl80211_msg_put_channel(struct sk_buff *msg,
         if ((chan->flags & IEEE80211_CHAN_NO_IBSS) &&
             nla_put_flag(msg, NL80211_FREQUENCY_ATTR_NO_IBSS))
                 goto nla_put_failure;
-        if ((chan->flags & IEEE80211_CHAN_RADAR) &&
-            nla_put_flag(msg, NL80211_FREQUENCY_ATTR_RADAR))
-                goto nla_put_failure;
+        if (chan->flags & IEEE80211_CHAN_RADAR) {
+                u32 time = elapsed_jiffies_msecs(chan->dfs_state_entered);
+                if (nla_put_flag(msg, NL80211_FREQUENCY_ATTR_RADAR))
+                        goto nla_put_failure;
+                if (nla_put_u32(msg, NL80211_FREQUENCY_ATTR_DFS_STATE,
+                                chan->dfs_state))
+                        goto nla_put_failure;
+                if (nla_put_u32(msg, NL80211_FREQUENCY_ATTR_DFS_TIME, time))
+                        goto nla_put_failure;
+        }
 
         if (nla_put_u32(msg, NL80211_FREQUENCY_ATTR_MAX_TX_POWER,
                         DBM_TO_MBM(chan->max_power)))
@@ -2775,6 +2782,7 @@ static int nl80211_start_ap(struct sk_buff *skb, struct genl_info *info)
         struct wireless_dev *wdev = dev->ieee80211_ptr;
         struct cfg80211_ap_settings params;
         int err;
+        u8 radar_detect_width = 0;
 
         if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_AP &&
             dev->ieee80211_ptr->iftype != NL80211_IFTYPE_P2P_GO)
@@ -2893,9 +2901,19 @@ static int nl80211_start_ap(struct sk_buff *skb, struct genl_info *info)
         if (!cfg80211_reg_can_beacon(&rdev->wiphy, &params.chandef))
                 return -EINVAL;
 
+        err = cfg80211_chandef_dfs_required(wdev->wiphy, &params.chandef);
+        if (err < 0)
+                return err;
+        if (err) {
+                radar_detect_width = BIT(params.chandef.width);
+                params.radar_required = true;
+        }
+
         mutex_lock(&rdev->devlist_mtx);
-        err = cfg80211_can_use_chan(rdev, wdev, params.chandef.chan,
-                                    CHAN_MODE_SHARED);
+        err = cfg80211_can_use_iftype_chan(rdev, wdev, wdev->iftype,
+                                           params.chandef.chan,
+                                           CHAN_MODE_SHARED,
+                                           radar_detect_width);
         mutex_unlock(&rdev->devlist_mtx);
 
         if (err)
@@ -5055,6 +5073,54 @@ static int nl80211_stop_sched_scan(struct sk_buff *skb,
         return err;
 }
 
+static int nl80211_start_radar_detection(struct sk_buff *skb,
+                                         struct genl_info *info)
+{
+        struct cfg80211_registered_device *rdev = info->user_ptr[0];
+        struct net_device *dev = info->user_ptr[1];
+        struct wireless_dev *wdev = dev->ieee80211_ptr;
+        struct cfg80211_chan_def chandef;
+        int err;
+
+        err = nl80211_parse_chandef(rdev, info, &chandef);
+        if (err)
+                return err;
+
+        if (wdev->cac_started)
+                return -EBUSY;
+
+        err = cfg80211_chandef_dfs_required(wdev->wiphy, &chandef);
+        if (err < 0)
+                return err;
+
+        if (err == 0)
+                return -EINVAL;
+
+        if (chandef.chan->dfs_state != NL80211_DFS_USABLE)
+                return -EINVAL;
+
+        if (!rdev->ops->start_radar_detection)
+                return -EOPNOTSUPP;
+
+        mutex_lock(&rdev->devlist_mtx);
+        err = cfg80211_can_use_iftype_chan(rdev, wdev, wdev->iftype,
+                                           chandef.chan, CHAN_MODE_SHARED,
+                                           BIT(chandef.width));
+        if (err)
+                goto err_locked;
+
+        err = rdev->ops->start_radar_detection(&rdev->wiphy, dev, &chandef);
+        if (!err) {
+                wdev->channel = chandef.chan;
+                wdev->cac_started = true;
+                wdev->cac_start_time = jiffies;
+        }
+err_locked:
+        mutex_unlock(&rdev->devlist_mtx);
+
+        return err;
+}
+
 static int nl80211_send_bss(struct sk_buff *msg, struct netlink_callback *cb,
                             u32 seq, int flags,
                             struct cfg80211_registered_device *rdev,
@@ -8305,6 +8371,14 @@ static struct genl_ops nl80211_ops[] = {
                 .internal_flags = NL80211_FLAG_NEED_NETDEV |
                                   NL80211_FLAG_NEED_RTNL,
         },
+        {
+                .cmd = NL80211_CMD_RADAR_DETECT,
+                .doit = nl80211_start_radar_detection,
+                .policy = nl80211_policy,
+                .flags = GENL_ADMIN_PERM,
+                .internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+                                  NL80211_FLAG_NEED_RTNL,
+        },
 };
 
 static struct genl_multicast_group nl80211_mlme_mcgrp = {
@@ -9502,6 +9576,57 @@ nl80211_send_cqm_txe_notify(struct cfg80211_registered_device *rdev,
 }
 
 void
+nl80211_radar_notify(struct cfg80211_registered_device *rdev,
+                     struct cfg80211_chan_def *chandef,
+                     enum nl80211_radar_event event,
+                     struct net_device *netdev, gfp_t gfp)
+{
+        struct sk_buff *msg;
+        void *hdr;
+
+        msg = nlmsg_new(NLMSG_DEFAULT_SIZE, gfp);
+        if (!msg)
+                return;
+
+        hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_RADAR_DETECT);
+        if (!hdr) {
+                nlmsg_free(msg);
+                return;
+        }
+
+        if (nla_put_u32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx))
+                goto nla_put_failure;
+
+        /* NOP and radar events don't need a netdev parameter */
+        if (netdev) {
+                struct wireless_dev *wdev = netdev->ieee80211_ptr;
+
+                if (nla_put_u32(msg, NL80211_ATTR_IFINDEX, netdev->ifindex) ||
+                    nla_put_u64(msg, NL80211_ATTR_WDEV, wdev_id(wdev)))
+                        goto nla_put_failure;
+        }
+
+        if (nla_put_u32(msg, NL80211_ATTR_RADAR_EVENT, event))
+                goto nla_put_failure;
+
+        if (nl80211_send_chandef(msg, chandef))
+                goto nla_put_failure;
+
+        if (genlmsg_end(msg, hdr) < 0) {
+                nlmsg_free(msg);
+                return;
+        }
+
+        genlmsg_multicast_netns(wiphy_net(&rdev->wiphy), msg, 0,
+                                nl80211_mlme_mcgrp.id, gfp);
+        return;
+
+ nla_put_failure:
+        genlmsg_cancel(msg, hdr);
+        nlmsg_free(msg);
+}
+
+void
 nl80211_send_cqm_pktloss_notify(struct cfg80211_registered_device *rdev,
                                 struct net_device *netdev, const u8 *peer,
                                 u32 num_packets, gfp_t gfp)
diff --git a/net/wireless/nl80211.h b/net/wireless/nl80211.h
index 2acba8477e9d..b061da4919e1 100644
--- a/net/wireless/nl80211.h
+++ b/net/wireless/nl80211.h
@@ -108,6 +108,13 @@ nl80211_send_cqm_rssi_notify(struct cfg80211_registered_device *rdev,
                              struct net_device *netdev,
                              enum nl80211_cqm_rssi_threshold_event rssi_event,
                              gfp_t gfp);
+
+void
+nl80211_radar_notify(struct cfg80211_registered_device *rdev,
+                     struct cfg80211_chan_def *chandef,
+                     enum nl80211_radar_event event,
+                     struct net_device *netdev, gfp_t gfp);
+
 void
 nl80211_send_cqm_pktloss_notify(struct cfg80211_registered_device *rdev,
                                 struct net_device *netdev, const u8 *peer,
diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 08d3da2c70ab..e97d5b071ab6 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -884,6 +884,9 @@ static void handle_channel(struct wiphy *wiphy,
                 return;
         }
 
+        chan->dfs_state = NL80211_DFS_USABLE;
+        chan->dfs_state_entered = jiffies;
+
         chan->beacon_found = false;
         chan->flags = flags | bw_flags | map_regdom_flags(reg_rule->flags);
         chan->max_antenna_gain =
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index d0fc6da2d097..f0d9b5154bab 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -1210,16 +1210,6 @@ static void ieee80211_scan_add_ies(struct iw_request_info *info,
         }
 }
 
-static inline unsigned int elapsed_jiffies_msecs(unsigned long start)
-{
-        unsigned long end = jiffies;
-
-        if (end >= start)
-                return jiffies_to_msecs(end - start);
-
-        return jiffies_to_msecs(end + (MAX_JIFFY_OFFSET - start) + 1);
-}
-
 static char *
 ieee80211_bss(struct wiphy *wiphy, struct iw_request_info *info,
               struct cfg80211_internal_bss *bss, char *current_ev,
diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index c9cafb0ea95f..b7a531380e19 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -2051,6 +2051,21 @@ TRACE_EVENT(cfg80211_reg_can_beacon,
                   WIPHY_PR_ARG, CHAN_DEF_PR_ARG)
 );
 
+TRACE_EVENT(cfg80211_chandef_dfs_required,
+        TP_PROTO(struct wiphy *wiphy, struct cfg80211_chan_def *chandef),
+        TP_ARGS(wiphy, chandef),
+        TP_STRUCT__entry(
+                WIPHY_ENTRY
+                CHAN_DEF_ENTRY
+        ),
+        TP_fast_assign(
+                WIPHY_ASSIGN;
+                CHAN_DEF_ASSIGN(chandef);
+        ),
+        TP_printk(WIPHY_PR_FMT ", " CHAN_DEF_PR_FMT,
+                  WIPHY_PR_ARG, CHAN_DEF_PR_ARG)
+);
+
 TRACE_EVENT(cfg80211_ch_switch_notify,
         TP_PROTO(struct net_device *netdev,
                  struct cfg80211_chan_def *chandef),
@@ -2067,6 +2082,36 @@ TRACE_EVENT(cfg80211_ch_switch_notify,
                   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),
+        TP_STRUCT__entry(
+                WIPHY_ENTRY
+                CHAN_DEF_ENTRY
+        ),
+        TP_fast_assign(
+                WIPHY_ASSIGN;
+                CHAN_DEF_ASSIGN(chandef);
+        ),
+        TP_printk(WIPHY_PR_FMT ", " CHAN_DEF_PR_FMT,
+                  WIPHY_PR_ARG, CHAN_DEF_PR_ARG)
+);
+
+TRACE_EVENT(cfg80211_cac_event,
+        TP_PROTO(struct net_device *netdev, enum nl80211_radar_event evt),
+        TP_ARGS(netdev, evt),
+        TP_STRUCT__entry(
+                NETDEV_ENTRY
+                __field(enum nl80211_radar_event, evt)
+        ),
+        TP_fast_assign(
+                NETDEV_ASSIGN;
+                __entry->evt = evt;
+        ),
+        TP_printk(NETDEV_PR_FMT ",  event: %d",
+                  NETDEV_PR_ARG, __entry->evt)
+);
+
 DECLARE_EVENT_CLASS(cfg80211_rx_evt,
         TP_PROTO(struct net_device *netdev, const u8 *addr),
         TP_ARGS(netdev, addr),