[PATCH v2 0/2] Stop scheduled scan if netlink client disappears

[PATCH v2 0/2] Stop scheduled scan if netlink client disappears

[Jukka Rissanen]

Hi,

v2:

- split the patch
- In patch 1, use a generic NL80211_ATTR_SOCKET_OWNER attribute and
  convert the old code that uses NL80211_ATTR_IFACE_SOCKET_OWNER to
  use the new value. A define is provided for backward compatibility.
- Any pending schedule scan stop worker is cancelled when interface is
  taken down in patch 2

Cheers,
Jukka


Jukka Rissanen (2):
  nl80211: Replace interface socket owner attribute with more generic
    one
  nl80211: Stop scheduled scan if netlink client disappears

 include/net/cfg80211.h       |  2 ++
 include/uapi/linux/nl80211.h | 11 ++++++++---
 net/wireless/core.c          | 10 +++++++++-
 net/wireless/nl80211.c       | 38 ++++++++++++++++++++++++++++++++++++--
 4 files changed, 55 insertions(+), 6 deletions(-)

-- 
1.8.3.1

[PATCH v2 1/2] nl80211: Replace interface socket owner attribute with more generic one

[Jukka Rissanen]

Replace NL80211_ATTR_IFACE_SOCKET_OWNER attribute with more generic
NL80211_ATTR_SOCKET_OWNER that can be used with other commands
that interface creation.
---
 include/uapi/linux/nl80211.h | 8 +++++---
 net/wireless/nl80211.c       | 4 ++--
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 442369f..c410284 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -1637,9 +1637,9 @@ enum nl80211_commands {
  * @NL80211_ATTR_TDLS_PEER_CAPABILITY: flags for TDLS peer capabilities, u32.
  *	As specified in the &enum nl80211_tdls_peer_capability.
  *
- * @NL80211_ATTR_IFACE_SOCKET_OWNER: flag attribute, if set during interface
+ * @NL80211_ATTR_SOCKET_OWNER: Flag attribute, if set during interface
  *	creation then the new interface will be owned by the netlink socket
- *	that created it and will be destroyed when the socket is closed
+ *	that created it and will be destroyed when the socket is closed.
  *
  * @NL80211_ATTR_TDLS_INITIATOR: flag attribute indicating the current end is
  *	the TDLS link initiator.
@@ -2004,7 +2004,7 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_TDLS_PEER_CAPABILITY,
 
-	NL80211_ATTR_IFACE_SOCKET_OWNER,
+	NL80211_ATTR_SOCKET_OWNER,
 
 	NL80211_ATTR_CSA_C_OFFSETS_TX,
 	NL80211_ATTR_MAX_CSA_COUNTERS,
@@ -2056,6 +2056,8 @@ enum nl80211_attrs {
 #define NL80211_ATTR_KEY NL80211_ATTR_KEY
 #define NL80211_ATTR_KEYS NL80211_ATTR_KEYS
 #define NL80211_ATTR_FEATURE_FLAGS NL80211_ATTR_FEATURE_FLAGS
+#define NL80211_ATTR_IFACE_SOCKET_OWNER NL80211_ATTR_SOCKET_OWNER
+#define NL80211_ATTR_SOCKET_OWNER NL80211_ATTR_SOCKET_OWNER
 
 #define NL80211_MAX_SUPP_RATES			32
 #define NL80211_MAX_SUPP_HT_RATES		77
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index d0a8361..df447c0 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -388,7 +388,7 @@ static const struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] = {
 	[NL80211_ATTR_MAC_HINT] = { .len = ETH_ALEN },
 	[NL80211_ATTR_WIPHY_FREQ_HINT] = { .type = NLA_U32 },
 	[NL80211_ATTR_TDLS_PEER_CAPABILITY] = { .type = NLA_U32 },
-	[NL80211_ATTR_IFACE_SOCKET_OWNER] = { .type = NLA_FLAG },
+	[NL80211_ATTR_SOCKET_OWNER] = { .type = NLA_FLAG },
 	[NL80211_ATTR_CSA_C_OFFSETS_TX] = { .type = NLA_BINARY },
 	[NL80211_ATTR_USE_RRM] = { .type = NLA_FLAG },
 	[NL80211_ATTR_TSID] = { .type = NLA_U8 },
@@ -2646,7 +2646,7 @@ static int nl80211_new_interface(struct sk_buff *skb, struct genl_info *info)
 		return PTR_ERR(wdev);
 	}
 
-	if (info->attrs[NL80211_ATTR_IFACE_SOCKET_OWNER])
+	if (info->attrs[NL80211_ATTR_SOCKET_OWNER])
 		wdev->owner_nlportid = info->snd_portid;
 
 	switch (type) {
-- 
1.8.3.1

[PATCH v2 2/2] nl80211: Stop scheduled scan if netlink client disappears

[Jukka Rissanen]

An attribute NL80211_ATTR_SOCKET_OWNER can be set by the scan initiator.
If present, the attribute will cause the scan to be stopped if the client
dies.
---
 include/net/cfg80211.h       |  2 ++
 include/uapi/linux/nl80211.h |  3 +++
 net/wireless/core.c          | 10 +++++++++-
 net/wireless/nl80211.c       | 34 ++++++++++++++++++++++++++++++++++
 4 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 220d5f5..84378bf 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1512,6 +1512,8 @@ struct cfg80211_sched_scan_request {
 	struct wiphy *wiphy;
 	struct net_device *dev;
 	unsigned long scan_start;
+	u32 owner_nlportid;
+	struct work_struct sched_scan_stop_wk;
 
 	/* keep last */
 	struct ieee80211_channel *channels[0];
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index c410284..310dc9b 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -1640,6 +1640,9 @@ enum nl80211_commands {
  * @NL80211_ATTR_SOCKET_OWNER: Flag attribute, if set during interface
  *	creation then the new interface will be owned by the netlink socket
  *	that created it and will be destroyed when the socket is closed.
+ *	If set during scheduled scan start then the new scan req will be
+ *	owned by the netlink socket that created it and the scheduled scan will
+ *	be stopped when the socket is closed.
  *
  * @NL80211_ATTR_TDLS_INITIATOR: flag attribute indicating the current end is
  *	the TDLS link initiator.
diff --git a/net/wireless/core.c b/net/wireless/core.c
index a4d2792..88898d9 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -840,6 +840,8 @@ void __cfg80211_leave(struct cfg80211_registered_device *rdev,
 		      struct wireless_dev *wdev)
 {
 	struct net_device *dev = wdev->netdev;
+	struct cfg80211_sched_scan_request *sched_scan_req =
+		rdev->sched_scan_req;
 
 	ASSERT_RTNL();
 	ASSERT_WDEV_LOCK(wdev);
@@ -850,8 +852,10 @@ void __cfg80211_leave(struct cfg80211_registered_device *rdev,
 		break;
 	case NL80211_IFTYPE_P2P_CLIENT:
 	case NL80211_IFTYPE_STATION:
-		if (rdev->sched_scan_req && dev == rdev->sched_scan_req->dev)
+		if (sched_scan_req && dev == sched_scan_req->dev) {
+			cancel_work_sync(&sched_scan_req->sched_scan_stop_wk);
 			__cfg80211_stop_sched_scan(rdev, false);
+		}
 
 #ifdef CONFIG_CFG80211_WEXT
 		kfree(wdev->wext.ie);
@@ -991,6 +995,10 @@ static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
 
 		if (WARN_ON(rdev->sched_scan_req &&
 			    rdev->sched_scan_req->dev == wdev->netdev)) {
+			struct cfg80211_sched_scan_request *sched_scan_req =
+				rdev->sched_scan_req;
+
+			cancel_work_sync(&sched_scan_req->sched_scan_stop_wk);
 			__cfg80211_stop_sched_scan(rdev, false);
 		}
 
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index df447c0..8fc500d 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -5681,6 +5681,21 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
 	return err;
 }
 
+static void nl80211_sched_scan_stop_wk(struct work_struct *work)
+{
+	struct cfg80211_sched_scan_request *req;
+	struct cfg80211_registered_device *rdev;
+
+	req = container_of(work, struct cfg80211_sched_scan_request,
+			   sched_scan_stop_wk);
+
+	rdev = wiphy_to_rdev(req->wiphy);
+
+	rtnl_lock();
+	__cfg80211_stop_sched_scan(rdev, false);
+	rtnl_unlock();
+}
+
 static int nl80211_start_sched_scan(struct sk_buff *skb,
 				    struct genl_info *info)
 {
@@ -5955,6 +5970,13 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
 
 	err = rdev_sched_scan_start(rdev, dev, request);
 	if (!err) {
+		if (info->attrs[NL80211_ATTR_SOCKET_OWNER]) {
+			INIT_WORK(&request->sched_scan_stop_wk,
+				  nl80211_sched_scan_stop_wk);
+
+			request->owner_nlportid = info->snd_portid;
+		}
+
 		rdev->sched_scan_req = request;
 		nl80211_send_sched_scan(rdev, dev,
 					NL80211_CMD_START_SCHED_SCAN);
@@ -12127,6 +12149,12 @@ static int nl80211_netlink_notify(struct notifier_block * nb,
 
 	list_for_each_entry_rcu(rdev, &cfg80211_rdev_list, list) {
 		bool schedule_destroy_work = false;
+		bool schedule_scan_stop = false;
+		struct cfg80211_sched_scan_request *req = rdev->sched_scan_req;
+
+		if (req && req->owner_nlportid == notify->portid &&
+		    notify->portid)
+			schedule_scan_stop = true;
 
 		list_for_each_entry_rcu(wdev, &rdev->wdev_list, list) {
 			cfg80211_mlme_unregister_socket(wdev, notify->portid);
@@ -12157,6 +12185,12 @@ static int nl80211_netlink_notify(struct notifier_block * nb,
 				spin_unlock(&rdev->destroy_list_lock);
 				schedule_work(&rdev->destroy_work);
 			}
+		} else if (schedule_scan_stop) {
+			req->owner_nlportid = 0;
+
+			if (rdev->ops->sched_scan_stop &&
+			    rdev->wiphy.flags & WIPHY_FLAG_SUPPORTS_SCHED_SCAN)
+				schedule_work(&req->sched_scan_stop_wk);
 		}
 	}
 
-- 
1.8.3.1

Re: [PATCH v2 1/2] nl80211: Replace interface socket owner attribute with more generic one

[Luca Coelho]

On Wed, 2014-11-12 at 13:36 +0200, Jukka Rissanen wrote:
> @@ -2056,6 +2056,8 @@ enum nl80211_attrs {
>  #define NL80211_ATTR_KEY NL80211_ATTR_KEY
>  #define NL80211_ATTR_KEYS NL80211_ATTR_KEYS
>  #define NL80211_ATTR_FEATURE_FLAGS NL80211_ATTR_FEATURE_FLAGS
> +#define NL80211_ATTR_IFACE_SOCKET_OWNER NL80211_ATTR_SOCKET_OWNER
> +#define NL80211_ATTR_SOCKET_OWNER NL80211_ATTR_SOCKET_OWNER

The second define seems to be a mistake?

--
Luca.

Re: [PATCH v2 1/2] nl80211: Replace interface socket owner attribute with more generic one

[Johannes Berg]

On Wed, 2014-11-12 at 13:47 +0200, Luca Coelho wrote:
> On Wed, 2014-11-12 at 13:36 +0200, Jukka Rissanen wrote:
> > @@ -2056,6 +2056,8 @@ enum nl80211_attrs {
> >  #define NL80211_ATTR_KEY NL80211_ATTR_KEY
> >  #define NL80211_ATTR_KEYS NL80211_ATTR_KEYS
> >  #define NL80211_ATTR_FEATURE_FLAGS NL80211_ATTR_FEATURE_FLAGS
> > +#define NL80211_ATTR_IFACE_SOCKET_OWNER NL80211_ATTR_SOCKET_OWNER
> > +#define NL80211_ATTR_SOCKET_OWNER NL80211_ATTR_SOCKET_OWNER
> 
> The second define seems to be a mistake?

Yes, both are wrong here. We played with defining some attributes to
themselves to allow #ifdef feature detection, but that didn't really
work out well and now we just copy nl80211.h to the userspace tools
needing a recent version. I think that's no longer needed now.

There should already be a second block of #ifdefs though that has
renamed ones, so you should add this one there.

Your patch is also missing signed-off-by.

johannes