cfg80211: Disallow moving out of operating DFS channel in non-ETSI

For non-ETSI regulatory domain, CAC result on DFS channel
may not be valid once moving out of that channel (as done
during remain-on-channel, scannning and off-channel tx).
Running CAC on an operating DFS channel after every off-channel
operation will only add complexity and disturb the current
link. Better do not allow any off-channel switch from a DFS
operating channel in non-ETSI domain.

Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qti.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index d516527fcb8eaf490d04f8f1fa4a82247c2d96cf..b15903b9c0ab1ecdbf958460d74e086ac96b2cee 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -6556,6 +6556,19 @@ static int nl80211_parse_random_mac(struct nlattr **attrs,
        return 0;
 }
 
+static bool cfg80211_off_channel_oper_allowed(struct wireless_dev *wdev)
+{
+       ASSERT_WDEV_LOCK(wdev);
+
+       if (!cfg80211_beaconing_iface_active(wdev))
+               return true;
+
+       if (!(wdev->chandef.chan->flags & IEEE80211_CHAN_RADAR))
+               return true;
+
+       return regulatory_pre_cac_allowed(wdev->wiphy);
+}
+
 static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
 {
        struct cfg80211_registered_device *rdev = info->user_ptr[0];
@@ -6681,6 +6694,25 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
 
        request->n_channels = i;
 
+       wdev_lock(wdev);
+       if (!cfg80211_off_channel_oper_allowed(wdev)) {
+               struct ieee80211_channel *chan;
+
+               if (request->n_channels != 1) {
+                       wdev_unlock(wdev);
+                       err = -EBUSY;
+                       goto out_free;
+               }
+
+               chan = request->channels[0];
+               if (chan->center_freq != wdev->chandef.chan->center_freq) {
+                       wdev_unlock(wdev);
+                       err = -EBUSY;
+                       goto out_free;
+               }
+       }
+       wdev_unlock(wdev);
+
        i = 0;
        if (n_ssids) {
                nla_for_each_nested(attr, info->attrs[NL80211_ATTR_SCAN_SSIDS], tmp) {
@@ -9103,6 +9135,7 @@ static int nl80211_remain_on_channel(struct sk_buff *skb,
        struct cfg80211_registered_device *rdev = info->user_ptr[0];
        struct wireless_dev *wdev = info->user_ptr[1];
        struct cfg80211_chan_def chandef;
+       const struct cfg80211_chan_def *compat_chandef;
        struct sk_buff *msg;
        void *hdr;
        u64 cookie;
@@ -9131,6 +9164,18 @@ static int nl80211_remain_on_channel(struct sk_buff *skb,
        if (err)
                return err;
 
+       wdev_lock(wdev);
+       if (!cfg80211_off_channel_oper_allowed(wdev) &&
+           !cfg80211_chandef_identical(&wdev->chandef, &chandef)) {
+               compat_chandef = cfg80211_chandef_compatible(&wdev->chandef,
+                                                            &chandef);
+               if (compat_chandef != &chandef) {
+                       wdev_unlock(wdev);
+                       return -EBUSY;
+               }
+       }
+       wdev_unlock(wdev);
+
        msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
        if (!msg)
                return -ENOMEM;
@@ -9306,6 +9351,13 @@ static int nl80211_tx_mgmt(struct sk_buff *skb, struct genl_info *info)
        if (!chandef.chan && params.offchan)
                return -EINVAL;
 
+       wdev_lock(wdev);
+       if (params.offchan && !cfg80211_off_channel_oper_allowed(wdev)) {
+               wdev_unlock(wdev);
+               return -EBUSY;
+       }
+       wdev_unlock(wdev);
+
        params.buf = nla_data(info->attrs[NL80211_ATTR_FRAME]);
        params.len = nla_len(info->attrs[NL80211_ATTR_FRAME]);