cfg80211: allow registering to beacons

Add the ability to register to received beacon frames
to allow implementing OLBC logic in userspace. The
registration is per wiphy since there's no point in
receiving the same frame multiple times.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 71 insertions, 1 deletions

diff --git a/net/wireless/core.h b/net/wireless/core.h
index a570ff9214ec..a020d38ea039 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -54,6 +54,8 @@ struct cfg80211_registered_device {
 	int opencount; /* also protected by devlist_mtx */
 	wait_queue_head_t dev_wait;
 
+	u32 ap_beacons_nlpid;
+
 	/* BSSes/scanning */
 	spinlock_t bss_lock;
 	struct list_head bss_list;
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index f0a03b62dca9..752d5425adca 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -885,6 +885,10 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
 	if (dev->wiphy.flags & WIPHY_FLAG_SUPPORTS_SCHED_SCAN)
 		CMD(sched_scan_start, START_SCHED_SCAN);
 	CMD(probe_client, PROBE_CLIENT);
+	if (dev->wiphy.flags & WIPHY_FLAG_REPORTS_OBSS) {
+		i++;
+		NLA_PUT_U32(msg, i, NL80211_CMD_REGISTER_BEACONS);
+	}
 
 #undef CMD
 
@@ -5651,6 +5655,21 @@ static int nl80211_probe_client(struct sk_buff *skb,
 	return err;
 }
 
+static int nl80211_register_beacons(struct sk_buff *skb, struct genl_info *info)
+{
+	struct cfg80211_registered_device *rdev = info->user_ptr[0];
+
+	if (!(rdev->wiphy.flags & WIPHY_FLAG_REPORTS_OBSS))
+		return -EOPNOTSUPP;
+
+	if (rdev->ap_beacons_nlpid)
+		return -EBUSY;
+
+	rdev->ap_beacons_nlpid = info->snd_pid;
+
+	return 0;
+}
+
 #define NL80211_FLAG_NEED_WIPHY		0x01
 #define NL80211_FLAG_NEED_NETDEV	0x02
 #define NL80211_FLAG_NEED_RTNL		0x04
@@ -6221,6 +6240,14 @@ static struct genl_ops nl80211_ops[] = {
 		.internal_flags = NL80211_FLAG_NEED_NETDEV |
 				  NL80211_FLAG_NEED_RTNL,
 	},
+	{
+		.cmd = NL80211_CMD_REGISTER_BEACONS,
+		.doit = nl80211_register_beacons,
+		.policy = nl80211_policy,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = NL80211_FLAG_NEED_WIPHY |
+				  NL80211_FLAG_NEED_RTNL,
+	},
 };
 
 static struct genl_multicast_group nl80211_mlme_mcgrp = {
@@ -7384,6 +7411,44 @@ void cfg80211_probe_status(struct net_device *dev, const u8 *addr,
 }
 EXPORT_SYMBOL(cfg80211_probe_status);
 
+void cfg80211_report_obss_beacon(struct wiphy *wiphy,
+				 const u8 *frame, size_t len,
+				 int freq, gfp_t gfp)
+{
+	struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);
+	struct sk_buff *msg;
+	void *hdr;
+	u32 nlpid = ACCESS_ONCE(rdev->ap_beacons_nlpid);
+
+	if (!nlpid)
+		return;
+
+	msg = nlmsg_new(len + 100, gfp);
+	if (!msg)
+		return;
+
+	hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_FRAME);
+	if (!hdr) {
+		nlmsg_free(msg);
+		return;
+	}
+
+	NLA_PUT_U32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx);
+	if (freq)
+		NLA_PUT_U32(msg, NL80211_ATTR_WIPHY_FREQ, freq);
+	NLA_PUT(msg, NL80211_ATTR_FRAME, len, frame);
+
+	genlmsg_end(msg, hdr);
+
+	genlmsg_unicast(wiphy_net(&rdev->wiphy), msg, nlpid);
+	return;
+
+ nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	nlmsg_free(msg);
+}
+EXPORT_SYMBOL(cfg80211_report_obss_beacon);
+
 static int nl80211_netlink_notify(struct notifier_block * nb,
 				  unsigned long state,
 				  void *_notify)
@@ -7397,9 +7462,12 @@ static int nl80211_netlink_notify(struct notifier_block * nb,
 
 	rcu_read_lock();
 
-	list_for_each_entry_rcu(rdev, &cfg80211_rdev_list, list)
+	list_for_each_entry_rcu(rdev, &cfg80211_rdev_list, list) {
 		list_for_each_entry_rcu(wdev, &rdev->netdev_list, list)
 			cfg80211_mlme_unregister_socket(wdev, notify->pid);
+		if (rdev->ap_beacons_nlpid == notify->pid)
+			rdev->ap_beacons_nlpid = 0;
+	}
 
 	rcu_read_unlock();