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.
Signed-off-by: Jukka Rissanen <[email protected]>
---
Hi,
v6:
- moved owner netlink port id from cfg80211_sched_scan_request to
rdev in order to avoid possible races
v5:
- discarded the locking changes in v4
- instead of trying to schedule sched_scan_stop worker from
struct cfg80211_sched_scan_request, move the worker to wiphy
as that makes it easier to manage the sched_scan_stop worker.
There are also one scheduled scan / wiphy so it is also logical
to do it like this.
v4:
- rtnl locking issues fixed in patch 2
v3:
- backward compatibility define tweaked in patch 1
- added missing signed-off-by:
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
include/uapi/linux/nl80211.h | 3 +++
net/wireless/core.c | 17 +++++++++++++++++
net/wireless/core.h | 2 ++
net/wireless/nl80211.c | 14 ++++++++++++++
4 files changed, 36 insertions(+)
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 185f9c7..5038240 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..6fffcb3 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -320,6 +320,21 @@ static void cfg80211_destroy_iface_wk(struct work_struct *work)
rtnl_unlock();
}
+static void cfg80211_sched_scan_stop_wk(struct work_struct *work)
+{
+ struct cfg80211_registered_device *rdev;
+
+ rdev = container_of(work, struct cfg80211_registered_device,
+ sched_scan_stop_wk);
+
+ rtnl_lock();
+
+ if (rdev->sched_scan_req)
+ __cfg80211_stop_sched_scan(rdev, false);
+
+ rtnl_unlock();
+}
+
/* exported functions */
struct wiphy *wiphy_new_nm(const struct cfg80211_ops *ops, int sizeof_priv,
@@ -406,6 +421,7 @@ use_default_name:
INIT_LIST_HEAD(&rdev->destroy_list);
spin_lock_init(&rdev->destroy_list_lock);
INIT_WORK(&rdev->destroy_work, cfg80211_destroy_iface_wk);
+ INIT_WORK(&rdev->sched_scan_stop_wk, cfg80211_sched_scan_stop_wk);
#ifdef CONFIG_CFG80211_DEFAULT_PS
rdev->wiphy.flags |= WIPHY_FLAG_PS_ON_BY_DEFAULT;
@@ -760,6 +776,7 @@ void wiphy_unregister(struct wiphy *wiphy)
flush_work(&rdev->event_work);
cancel_delayed_work_sync(&rdev->dfs_update_channels_wk);
flush_work(&rdev->destroy_work);
+ flush_work(&rdev->sched_scan_stop_wk);
#ifdef CONFIG_PM
if (rdev->wiphy.wowlan_config && rdev->ops->set_wakeup)
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 61ee664..c27615e 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -67,6 +67,8 @@ struct cfg80211_registered_device {
unsigned long suspend_at;
struct work_struct scan_done_wk;
struct work_struct sched_scan_results_wk;
+ struct work_struct sched_scan_stop_wk;
+ u32 sched_scan_owner_nlportid;
struct genl_info *cur_cmd_info;
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index df447c0..9ed6a34 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -5955,6 +5955,9 @@ 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])
+ rdev->sched_scan_owner_nlportid = info->snd_portid;
+
rdev->sched_scan_req = request;
nl80211_send_sched_scan(rdev, dev,
NL80211_CMD_START_SCHED_SCAN);
@@ -12127,6 +12130,11 @@ 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;
+
+ if (rdev->sched_scan_req && notify->portid &&
+ rdev->sched_scan_owner_nlportid == 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 +12165,12 @@ 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) {
+ rdev->sched_scan_owner_nlportid = 0;
+
+ if (rdev->ops->sched_scan_stop &&
+ rdev->wiphy.flags & WIPHY_FLAG_SUPPORTS_SCHED_SCAN)
+ schedule_work(&rdev->sched_scan_stop_wk);
}
}
--
1.8.3.1
Hi Johannes,
On to, 2014-11-20 at 16:14 +0100, Johannes Berg wrote:
> On Thu, 2014-11-20 at 13:32 +0200, Jukka Rissanen wrote:
>
> > - moved owner netlink port id from cfg80211_sched_scan_request to
> > rdev in order to avoid possible races
>
> How does that really help though? You're not really locking it anyway.
>
> I think you should consider keeping it inside the sched_scan_request,
> but maybe make that an __rcu pointer.
>
> Your patch also still has the problem I pointed out to you before - you
> can get the following sequence of events:
>
> start_sched_scan (owner=true)
> close socket - schedule worker
> start_sched_scan (from another socket, owner doesn't matter)
If I am reading the code correctly from
nl80211.c:nl80211_start_sched_scan() this socket will get -EINPROGRESS.
Only after the worker has finished and called
__cfg80211_stop_sched_scan() will the other socket able to start a new
scheduled scan. Or I might have just missed some important detail
here :)
> run worker - cancels the new sched_scan
>
> You need to make sure the worker is flushed in start_sched_scan or so,
> which might require RTNL work there or something.
>
> johannes
>
Cheers,
Jukka
On Fri, 2014-11-21 at 10:00 +0200, Jukka Rissanen wrote:
> > Your patch also still has the problem I pointed out to you before - you
> > can get the following sequence of events:
> >
> > start_sched_scan (owner=true)
> > close socket - schedule worker
> > start_sched_scan (from another socket, owner doesn't matter)
>
> If I am reading the code correctly from
> nl80211.c:nl80211_start_sched_scan() this socket will get -EINPROGRESS.
> Only after the worker has finished and called
> __cfg80211_stop_sched_scan() will the other socket able to start a new
> scheduled scan. Or I might have just missed some important detail
> here :)
Oh, you're right, my mistake.
johannes
On Thu, 2014-11-20 at 13:32 +0200, Jukka Rissanen wrote:
> - moved owner netlink port id from cfg80211_sched_scan_request to
> rdev in order to avoid possible races
How does that really help though? You're not really locking it anyway.
I think you should consider keeping it inside the sched_scan_request,
but maybe make that an __rcu pointer.
Your patch also still has the problem I pointed out to you before - you
can get the following sequence of events:
start_sched_scan (owner=true)
close socket - schedule worker
start_sched_scan (from another socket, owner doesn't matter)
run worker - cancels the new sched_scan
You need to make sure the worker is flushed in start_sched_scan or so,
which might require RTNL work there or something.
johannes