cfg80211: allow registering more than one beacon listener

The commit:

commit 5e760230e42cf759bd923457ca2753aacf2e656e
Author: Johannes Berg <johannes.berg@intel.com>
Date:   Fri Nov 4 11:18:17 2011 +0100

    cfg80211: allow registering to beacons

allowed only a single process to register for beacon events
per wiphy.  This breaks cases where a user may want two or
more VIFs on a wiphy and run a seperate hostapd process on
each vif.

This patch allows multiple beacon listeners, fixing the
regression.

Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 60 insertions, 28 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 9b0a3b8fd20a..ba44f98c56d9 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -6934,16 +6934,35 @@ static int nl80211_probe_client(struct sk_buff *skb,
 static int nl80211_register_beacons(struct sk_buff *skb, struct genl_info *info)
 {
         struct cfg80211_registered_device *rdev = info->user_ptr[0];
+        struct cfg80211_beacon_registration *reg, *nreg;
+        int rv;
 
         if (!(rdev->wiphy.flags & WIPHY_FLAG_REPORTS_OBSS))
                 return -EOPNOTSUPP;
 
-        if (rdev->ap_beacons_nlportid)
-                return -EBUSY;
+        nreg = kzalloc(sizeof(*nreg), GFP_KERNEL);
+        if (!nreg)
+                return -ENOMEM;
+
+        /* First, check if already registered. */
+        spin_lock_bh(&rdev->beacon_registrations_lock);
+        list_for_each_entry(reg, &rdev->beacon_registrations, list) {
+                if (reg->nlportid == info->snd_portid) {
+                        rv = -EALREADY;
+                        goto out_err;
+                }
+        }
+        /* Add it to the list */
+        nreg->nlportid = info->snd_portid;
+        list_add(&nreg->list, &rdev->beacon_registrations);
 
-        rdev->ap_beacons_nlportid = info->snd_portid;
+        spin_unlock_bh(&rdev->beacon_registrations_lock);
 
         return 0;
+out_err:
+        spin_unlock_bh(&rdev->beacon_registrations_lock);
+        kfree(nreg);
+        return rv;
 }
 
 static int nl80211_start_p2p_device(struct sk_buff *skb, struct genl_info *info)
@@ -8957,43 +8976,46 @@ EXPORT_SYMBOL(cfg80211_probe_status);
 
 void cfg80211_report_obss_beacon(struct wiphy *wiphy,
                                  const u8 *frame, size_t len,
-                                 int freq, int sig_dbm, gfp_t gfp)
+                                 int freq, int sig_dbm)
 {
         struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);
         struct sk_buff *msg;
         void *hdr;
-        u32 nlportid = ACCESS_ONCE(rdev->ap_beacons_nlportid);
+        struct cfg80211_beacon_registration *reg;
 
         trace_cfg80211_report_obss_beacon(wiphy, frame, len, freq, sig_dbm);
 
-        if (!nlportid)
-                return;
-
-        msg = nlmsg_new(len + 100, gfp);
-        if (!msg)
-                return;
+        spin_lock_bh(&rdev->beacon_registrations_lock);
+        list_for_each_entry(reg, &rdev->beacon_registrations, list) {
+                msg = nlmsg_new(len + 100, GFP_ATOMIC);
+                if (!msg) {
+                        spin_unlock_bh(&rdev->beacon_registrations_lock);
+                        return;
+                }
 
-        hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_FRAME);
-        if (!hdr) {
-                nlmsg_free(msg);
-                return;
-        }
+                hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_FRAME);
+                if (!hdr)
+                        goto nla_put_failure;
 
-        if (nla_put_u32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx) ||
-            (freq &&
-             nla_put_u32(msg, NL80211_ATTR_WIPHY_FREQ, freq)) ||
-            (sig_dbm &&
-             nla_put_u32(msg, NL80211_ATTR_RX_SIGNAL_DBM, sig_dbm)) ||
-            nla_put(msg, NL80211_ATTR_FRAME, len, frame))
-                goto nla_put_failure;
+                if (nla_put_u32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx) ||
+                    (freq &&
+                     nla_put_u32(msg, NL80211_ATTR_WIPHY_FREQ, freq)) ||
+                    (sig_dbm &&
+                     nla_put_u32(msg, NL80211_ATTR_RX_SIGNAL_DBM, sig_dbm)) ||
+                    nla_put(msg, NL80211_ATTR_FRAME, len, frame))
+                        goto nla_put_failure;
 
-        genlmsg_end(msg, hdr);
+                genlmsg_end(msg, hdr);
 
-        genlmsg_unicast(wiphy_net(&rdev->wiphy), msg, nlportid);
+                genlmsg_unicast(wiphy_net(&rdev->wiphy), msg, reg->nlportid);
+        }
+        spin_unlock_bh(&rdev->beacon_registrations_lock);
         return;
 
  nla_put_failure:
-        genlmsg_cancel(msg, hdr);
+        spin_unlock_bh(&rdev->beacon_registrations_lock);
+        if (hdr)
+                genlmsg_cancel(msg, hdr);
         nlmsg_free(msg);
 }
 EXPORT_SYMBOL(cfg80211_report_obss_beacon);
@@ -9005,6 +9027,7 @@ static int nl80211_netlink_notify(struct notifier_block * nb,
         struct netlink_notify *notify = _notify;
         struct cfg80211_registered_device *rdev;
         struct wireless_dev *wdev;
+        struct cfg80211_beacon_registration *reg, *tmp;
 
         if (state != NETLINK_URELEASE)
                 return NOTIFY_DONE;
@@ -9014,8 +9037,17 @@ static int nl80211_netlink_notify(struct notifier_block * nb,
         list_for_each_entry_rcu(rdev, &cfg80211_rdev_list, list) {
                 list_for_each_entry_rcu(wdev, &rdev->wdev_list, list)
                         cfg80211_mlme_unregister_socket(wdev, notify->portid);
-                if (rdev->ap_beacons_nlportid == notify->portid)
-                        rdev->ap_beacons_nlportid = 0;
+
+                spin_lock_bh(&rdev->beacon_registrations_lock);
+                list_for_each_entry_safe(reg, tmp, &rdev->beacon_registrations,
+                                         list) {
+                        if (reg->nlportid == notify->portid) {
+                                list_del(&reg->list);
+                                kfree(reg);
+                                break;
+                        }
+                }
+                spin_unlock_bh(&rdev->beacon_registrations_lock);
         }
 
         rcu_read_unlock();