by Vasanthakumar Thiagarajan

[permalink] [raw]

Subject: [RFC 2/3] 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 <[email protected]>
---
net/wireless/nl80211.c | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 63dfa60..c614af4 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -6506,6 +6506,17 @@ static int nl80211_parse_random_mac(struct nlattr **attrs,
return 0;
}

+static bool cfg80211_off_channel_oper_allowed(struct wireless_dev *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];
@@ -6631,6 +6642,21 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)

request->n_channels = i;

+ if (!cfg80211_off_channel_oper_allowed(wdev)) {
+ struct ieee80211_channel *chan;
+
+ if (request->n_channels != 1) {
+ err = -EBUSY;
+ goto out_free;
+ }
+
+ chan = request->channels[0];
+ if (chan->center_freq != wdev->chandef.chan->center_freq) {
+ err = -EBUSY;
+ goto out_free;
+ }
+ }
+
i = 0;
if (n_ssids) {
nla_for_each_nested(attr, info->attrs[NL80211_ATTR_SCAN_SSIDS], tmp) {
@@ -9053,6 +9079,7 @@ 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;
@@ -9081,6 +9108,14 @@ static int nl80211_remain_on_channel(struct sk_buff *skb,
if (err)
return err;

+ 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)
+ return -EBUSY;
+ }
+
msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
if (!msg)
return -ENOMEM;
@@ -9256,6 +9291,9 @@ static int nl80211_tx_mgmt(struct sk_buff *skb, struct genl_info *info)
if (!chandef.chan && params.offchan)
return -EINVAL;

+ if (params.offchan && !cfg80211_off_channel_oper_allowed(wdev))
+ return -EBUSY;
+
params.buf = nla_data(info->attrs[NL80211_ATTR_FRAME]);
params.len = nla_len(info->attrs[NL80211_ATTR_FRAME]);

--
1.9.1

2017-01-26 09:41:24

by Johannes Berg

[permalink] [raw]

Subject: Re: [RFC 3/3] cfg80211: Share Channel DFS state across wiphys of same DFS domain

On Wed, 2017-01-25 at 17:01 +0530, Vasanthakumar Thiagarajan wrote:
> Sharing DFS channel state across multiple wiphys (radios) could
> be useful with multiple radios on the system. When one radio
> completes CAC and marks the channel available another radio
> can use this information and start beaconing without really doing
> CAC.
>
> Whenever there is a state change in DFS channel associated to
> a particular wiphy the the same state change is propagated to
> other wiphys having the same DFS reg domain configuration.
> Also when a new wiphy is created the DFS channel state of
> other existing wiphys of same DFS domain is copied.
>
> Signed-off-by: Vasanthakumar Thiagarajan <[email protected]>
> ---
> net/wireless/chan.c |  24 +++++++++--
> net/wireless/core.c |  37 +++++++++++++++++
> net/wireless/core.h |   6 +++
> net/wireless/mlme.c |  11 +++++-
> net/wireless/reg.c  | 112
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
> net/wireless/reg.h  |  22 +++++++++++
> 6 files changed, 207 insertions(+), 5 deletions(-)
>
> diff --git a/net/wireless/chan.c b/net/wireless/chan.c
> index 090309a..40f1097 100644
> --- a/net/wireless/chan.c
> +++ b/net/wireless/chan.c
> @@ -532,21 +532,37 @@ bool cfg80211_beaconing_iface_active(struct
> wireless_dev *wdev)
> return active;
> }
>
> +static bool cfg80211_5ghz_is_wiphy_oper_chan(struct wiphy *wiphy,
> +      struct
> ieee80211_channel *chan)

again, nothing really 5 GHz specific here, afaict?

> + struct wireless_dev *wdev;
> +
> + list_for_each_entry(wdev, &wiphy->wdev_list, list) {
> + if (!cfg80211_beaconing_iface_active(wdev))
> + continue;
> +
> + if (cfg80211_5ghz_sub_chan(&wdev->chandef, chan))
> + return true;
> + }
> +
> + return false;
> +}
> +
> bool cfg80211_5ghz_any_wiphy_oper_chan(struct wiphy *wiphy,
>        struct ieee80211_channel
> *chan)
> {
> - struct wireless_dev *wdev;
> + struct cfg80211_registered_device *rdev;
>
> ASSERT_RTNL();
>
> if (!(chan->flags & IEEE80211_CHAN_RADAR))
> return false;
>
> - list_for_each_entry(wdev, &wiphy->wdev_list, list) {
> - if (!cfg80211_beaconing_iface_active(wdev))
> + list_for_each_entry(rdev, &cfg80211_rdev_list, list) {
> + if (!reg_dfs_domain_same(wiphy, &rdev->wiphy))
> continue;
>
> - if (cfg80211_5ghz_sub_chan(&wdev->chandef, chan))
> + if (cfg80211_5ghz_is_wiphy_oper_chan(&rdev->wiphy,
> chan))
> return true;
> }
>
> diff --git a/net/wireless/core.c b/net/wireless/core.c
> index 903fc419..c3fe44b 100644
> --- a/net/wireless/core.c
> +++ b/net/wireless/core.c
> @@ -357,6 +357,38 @@ static void cfg80211_sched_scan_stop_wk(struct
> work_struct *work)
> rtnl_unlock();
> }
>
> +static void cfg80211_propagate_radar_detect_wk(struct work_struct
> *work)
> +{
> + struct cfg80211_registered_device *rdev;
> +
> + rdev = container_of(work, struct cfg80211_registered_device,
> +     porpagate_radar_detect_wk);
> +
> + rtnl_lock();
> +
> + regulatory_propagate_dfs_state(&rdev->wiphy, &rdev-
> >radar_chandef,
> +        NL80211_DFS_UNAVAILABLE,
> +        NL80211_RADAR_DETECTED);
> +
> + rtnl_unlock();
> +}
> +
> +static void cfg80211_propagate_cac_done_wk(struct work_struct *work)
> +{
> + struct cfg80211_registered_device *rdev;
> +
> + rdev = container_of(work, struct cfg80211_registered_device,
> +     propagate_cac_done_wk);
> +
> + rtnl_lock();
> +
> + regulatory_propagate_dfs_state(&rdev->wiphy, &rdev-
> >cac_done_chandef,
> +        NL80211_DFS_AVAILABLE,
> +        NL80211_RADAR_CAC_FINISHED);
> +
> + rtnl_unlock();
> +}
> +
> /* exported functions */
>
> struct wiphy *wiphy_new_nm(const struct cfg80211_ops *ops, int
> sizeof_priv,
> @@ -456,6 +488,9 @@ struct wiphy *wiphy_new_nm(const struct
> cfg80211_ops *ops, int sizeof_priv,
> 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);
> + INIT_WORK(&rdev->porpagate_radar_detect_wk,
> +   cfg80211_propagate_radar_detect_wk);
> + INIT_WORK(&rdev->propagate_cac_done_wk,
> cfg80211_propagate_cac_done_wk);
>
> #ifdef CONFIG_CFG80211_DEFAULT_PS
> rdev->wiphy.flags |= WIPHY_FLAG_PS_ON_BY_DEFAULT;
> @@ -914,6 +949,8 @@ void wiphy_unregister(struct wiphy *wiphy)
> flush_work(&rdev->destroy_work);
> flush_work(&rdev->sched_scan_stop_wk);
> flush_work(&rdev->mlme_unreg_wk);
> + flush_work(&rdev->porpagate_radar_detect_wk);

typo: propagate.

> + flush_work(&rdev->propagate_cac_done_wk);

You got it right here :)

> #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 327fe95..607c8be 100644
> --- a/net/wireless/core.h
> +++ b/net/wireless/core.h
> @@ -97,6 +97,12 @@ struct cfg80211_registered_device {
>
> struct work_struct sched_scan_stop_wk;
>
> + struct cfg80211_chan_def radar_chandef;
> + struct work_struct porpagate_radar_detect_wk;

Since it compiled, the typo exists everywhere this is referenced.

> +++ b/net/wireless/mlme.c
> @@ -18,7 +18,6 @@
> #include "nl80211.h"
> #include "rdev-ops.h"
>
> -
> void cfg80211_rx_assoc_resp(struct net_device *dev, struct
> cfg80211_bss *bss,

please don't make unrelated "cleanups".

> +bool reg_dfs_domain_same(struct wiphy *wiphy1, struct wiphy *wiphy2)
> +{
> + const struct ieee80211_regdomain *wiphy1_regd = NULL;
> + const struct ieee80211_regdomain *wiphy2_regd = NULL;
> + const struct ieee80211_regdomain *cfg80211_regd = NULL;
> + bool dfs_domain_same = false;

You can remove that initializer,

> + rcu_read_lock();
> +
> + cfg80211_regd = rcu_dereference(cfg80211_regdomain);
> + wiphy1_regd = rcu_dereference(wiphy1->regd);
> + if (!wiphy1_regd)
> + wiphy1_regd = cfg80211_regd;
> +
> + wiphy2_regd = rcu_dereference(wiphy2->regd);
> + if (!wiphy2_regd)
> + wiphy2_regd = cfg80211_regd;
> +
> + if (wiphy1_regd->dfs_region == wiphy2_regd->dfs_region)
> + dfs_domain_same = true;

and just assign
dfs_domain_same = wiphy1... == wiphy2...;

> +static void wiphy_share_dfs_chan_state(struct wiphy *dst_wiphy,
> +        struct wiphy *src_wiphy)
> +{
> + struct ieee80211_supported_band *src_sband, *dst_sband;
> + int i, j;
> +
> + dst_sband = dst_wiphy->bands[NL80211_BAND_5GHZ];
> + src_sband = src_wiphy->bands[NL80211_BAND_5GHZ];
> + if (!dst_sband || !src_sband)
> + return;

Why make this 5 GHz specific? Perhaps some kind of radar stuff will
exist in future bands too. It shouldn't really cost much to iterate all
the bands, I think?

johannes