The count field in CSA must be decremented with each beacon
transmitted. This patch implements the functionality for drivers
using ieee80211_beacon_get(). Other drivers must call back manually
after reaching count == 0.
This patch also contains the handling and finish worker for the channel
switch command.
Signed-off-by: Simon Wunderlich <siwu@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@xxxxxxxxxxxxxxxxxxx>
---
Changes to PATCHv3:
* forbid adding interfaces while CSA is running
* forbid calling CSA multiple times
* check for multiple channel contexts
* abort channel switch when going down while doing CSA
Changes to PATCHv2:
* fix documentation and style stuff
* update tracing
* change csa_active to bool
* check if csa_active when assigning beacons
* fix locking and access
* use new ieee80211_vif_change_channel to change the channel
Changes to PATCHv1:
* don't switch when CAC is active
* add hw to parameters for driver
Changes to RFCv1:
* use beacons as supplied from nl80211 without generating/parsing them
* update beacons using offsets
* report back by calling the channel switch event in cfg80211
squash mac80211: add channel switch command and beacon callbacks
Signed-off-by: Simon Wunderlich <siwu@xxxxxxxxxxxxxxxxxx>
---
include/net/mac80211.h | 34 ++++++++++++
net/mac80211/cfg.c | 132 +++++++++++++++++++++++++++++++++++++++++++-
net/mac80211/driver-ops.h | 13 +++++
net/mac80211/ieee80211_i.h | 13 +++++
net/mac80211/iface.c | 9 +++
net/mac80211/trace.h | 26 +++++++++
net/mac80211/tx.c | 80 +++++++++++++++++++++++++++
7 files changed, 305 insertions(+), 2 deletions(-)
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 2cc306c..1c1c18a 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1088,6 +1088,7 @@ enum ieee80211_vif_flags {
* @addr: address of this interface
* @p2p: indicates whether this AP or STA interface is a p2p
* interface, i.e. a GO or p2p-sta respectively
+ * @csa_active: marks whether a channel switch is going on
* @driver_flags: flags/capabilities the driver has for this interface,
* these need to be set (or cleared) when the interface is added
* or, if supported by the driver, the interface type is changed
@@ -1110,6 +1111,7 @@ struct ieee80211_vif {
struct ieee80211_bss_conf bss_conf;
u8 addr[ETH_ALEN];
bool p2p;
+ bool csa_active;
u8 cab_queue;
u8 hw_queue[IEEE80211_NUM_ACS];
@@ -2641,6 +2643,16 @@ enum ieee80211_roc_type {
* @ipv6_addr_change: IPv6 address assignment on the given interface changed.
* Currently, this is only called for managed or P2P client interfaces.
* This callback is optional; it must not sleep.
+ *
+ * @channel_switch_beacon: Starts a channel switch to a new channel.
+ * Beacons are modified to include CSA or ECSA IEs before calling this
+ * function. The corresponding count fields in these IEs must be
+ * decremented, and when they reach zero the driver must call
+ * ieee80211_csa_finish(). Drivers which use ieee80211_beacon_get()
+ * get the csa counter decremented by mac80211, but must check if it is
+ * zero using ieee80211_csa_is_complete() after the beacon has been
+ * transmitted and then call ieee80211_csa_finish().
+ *
*/
struct ieee80211_ops {
void (*tx)(struct ieee80211_hw *hw,
@@ -2828,6 +2840,9 @@ struct ieee80211_ops {
struct ieee80211_vif *vif,
struct inet6_dev *idev);
#endif
+ void (*channel_switch_beacon)(struct ieee80211_hw *hw,
+ struct ieee80211_vif *vif,
+ struct cfg80211_chan_def *chandef);
};
/**
@@ -3323,6 +3338,25 @@ static inline struct sk_buff *ieee80211_beacon_get(struct ieee80211_hw *hw,
}
/**
+ * ieee80211_csa_finish - notify mac80211 about channel switch
+ * @vif: &struct ieee80211_vif pointer from the add_interface callback.
+ *
+ * After a channel switch announcement was scheduled and the counter in this
+ * announcement hit zero, this function must be called by the driver to
+ * notify mac80211 that the channel can be changed.
+ */
+void ieee80211_csa_finish(struct ieee80211_vif *vif);
+
+/**
+ * ieee80211_csa_is_complete - find out if counters reached zero
+ * @vif: &struct ieee80211_vif pointer from the add_interface callback.
+ *
+ * This function returns whether the channel switch counters reached zero.
+ */
+bool ieee80211_csa_is_complete(struct ieee80211_vif *vif);
+
+
+/**
* ieee80211_proberesp_get - retrieve a Probe Response template
* @hw: pointer obtained from ieee80211_alloc_hw().
* @vif: &struct ieee80211_vif pointer from the add_interface callback.
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 8e6c935..33bfd26 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -860,8 +860,8 @@ static int ieee80211_set_probe_resp(struct ieee80211_sub_if_data *sdata,
return 0;
}
-static int ieee80211_assign_beacon(struct ieee80211_sub_if_data *sdata,
- struct cfg80211_beacon_data *params)
+int ieee80211_assign_beacon(struct ieee80211_sub_if_data *sdata,
+ struct cfg80211_beacon_data *params)
{
struct beacon_data *new, *old;
int new_head_len, new_tail_len;
@@ -1024,6 +1024,12 @@ static int ieee80211_change_beacon(struct wiphy *wiphy, struct net_device *dev,
sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+ /* don't allow changing the beacon while CSA is in place - offset
+ * of channel switch counter may change
+ */
+ if (sdata->vif.csa_active)
+ return -EBUSY;
+
old = rtnl_dereference(sdata->u.ap.beacon);
if (!old)
return -ENOENT;
@@ -1048,6 +1054,10 @@ static int ieee80211_stop_ap(struct wiphy *wiphy, struct net_device *dev)
return -ENOENT;
old_probe_resp = rtnl_dereference(sdata->u.ap.probe_resp);
+ /* abort any running channel switch */
+ sdata->vif.csa_active = false;
+ cancel_work_sync(&sdata->csa_finalize_work);
+
/* turn off carrier for this interface and dependent VLANs */
list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
netif_carrier_off(vlan->dev);
@@ -2831,6 +2841,123 @@ cfg80211_beacon_dup(struct cfg80211_beacon_data *beacon)
return new_beacon;
}
+void ieee80211_csa_finalize_work(struct work_struct *work)
+{
+ struct ieee80211_sub_if_data *sdata =
+ container_of(work, struct ieee80211_sub_if_data,
+ csa_finalize_work);
+ struct ieee80211_local *local = sdata->local;
+ int err, changed;
+
+ if (!ieee80211_sdata_running(sdata))
+ return;
+
+ if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP))
+ return;
+
+ sdata->radar_required = sdata->csa_radar_required;
+ err = ieee80211_vif_change_channel(sdata, &local->csa_chandef,
+ &changed);
+ if (WARN_ON(err < 0))
+ return;
+
+ err = ieee80211_assign_beacon(sdata, sdata->u.ap.next_beacon);
+ if (err < 0)
+ return;
+
+ changed |= err;
+ kfree(sdata->u.ap.next_beacon);
+ sdata->u.ap.next_beacon = NULL;
+
+ ieee80211_wake_queues_by_reason(&sdata->local->hw,
+ IEEE80211_MAX_QUEUE_MAP,
+ IEEE80211_QUEUE_STOP_REASON_CSA);
+
+ ieee80211_bss_info_change_notify(sdata, changed);
+
+ cfg80211_ch_switch_notify(sdata->dev, &local->csa_chandef);
+}
+
+static int ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
+ struct cfg80211_csa_settings *params)
+{
+ struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+ struct ieee80211_local *local = sdata->local;
+ struct ieee80211_chanctx_conf *chanctx_conf;
+ struct ieee80211_chanctx *chanctx;
+ int err, num_chanctx;
+
+ if (!list_empty(&local->roc_list) || local->scanning)
+ return -EBUSY;
+
+ if (sdata->wdev.cac_started)
+ return -EBUSY;
+
+ /* don't handle if chanctx is used */
+ if (local->use_chanctx)
+ return -EINVAL;
+
+ rcu_read_lock();
+ chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
+ if (!chanctx_conf) {
+ rcu_read_unlock();
+ return -EBUSY;
+ }
+
+ /* don't handle for multi-VIF cases */
+ chanctx = container_of(chanctx_conf, struct ieee80211_chanctx, conf);
+ if (chanctx->refcount > 1) {
+ rcu_read_unlock();
+ return -EBUSY;
+ }
+ num_chanctx = 0;
+ list_for_each_entry_rcu(chanctx, &local->chanctx_list, list)
+ num_chanctx++;
+
+ if (num_chanctx > 1) {
+ rcu_read_unlock();
+ return -EBUSY;
+ }
+ rcu_read_unlock();
+
+ /* don't allow another channel switch if one is already active. */
+ if (sdata->vif.csa_active)
+ return -EBUSY;
+
+ /* only handle AP for now. */
+ switch (sdata->vif.type) {
+ case NL80211_IFTYPE_AP:
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ sdata->u.ap.next_beacon = cfg80211_beacon_dup(¶ms->beacon_after);
+ if (!sdata->u.ap.next_beacon)
+ return -ENOMEM;
+
+ sdata->csa_counter_offset_beacon = params->counter_offset_beacon;
+ sdata->csa_counter_offset_presp = params->counter_offset_presp;
+ sdata->csa_radar_required = params->radar_required;
+
+ if (params->block_tx)
+ ieee80211_stop_queues_by_reason(&local->hw,
+ IEEE80211_MAX_QUEUE_MAP,
+ IEEE80211_QUEUE_STOP_REASON_CSA);
+
+ err = ieee80211_assign_beacon(sdata, ¶ms->beacon_csa);
+ if (err < 0)
+ return err;
+
+ local->csa_chandef = params->chandef;
+ sdata->vif.csa_active = true;
+
+ ieee80211_bss_info_change_notify(sdata, err);
+ drv_channel_switch_beacon(sdata, ¶ms->chandef);
+
+ return 0;
+}
+
static int ieee80211_mgmt_tx(struct wiphy *wiphy, struct wireless_dev *wdev,
struct ieee80211_channel *chan, bool offchan,
unsigned int wait, const u8 *buf, size_t len,
@@ -3548,4 +3675,5 @@ struct cfg80211_ops mac80211_config_ops = {
.get_et_strings = ieee80211_get_et_strings,
.get_channel = ieee80211_cfg_get_channel,
.start_radar_detection = ieee80211_start_radar_detection,
+ .channel_switch = ieee80211_channel_switch,
};
diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index b931c96..b3ea11f 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -1072,4 +1072,17 @@ static inline void drv_ipv6_addr_change(struct ieee80211_local *local,
}
#endif
+static inline void
+drv_channel_switch_beacon(struct ieee80211_sub_if_data *sdata,
+ struct cfg80211_chan_def *chandef)
+{
+ struct ieee80211_local *local = sdata->local;
+
+ if (local->ops->channel_switch_beacon) {
+ trace_drv_channel_switch_beacon(local, sdata, chandef);
+ local->ops->channel_switch_beacon(&local->hw, &sdata->vif,
+ chandef);
+ }
+}
+
#endif /* __MAC80211_DRIVER_OPS */
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 20dbc2d..73bcec3 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -259,6 +259,8 @@ struct ieee80211_if_ap {
struct beacon_data __rcu *beacon;
struct probe_resp __rcu *probe_resp;
+ /* to be used after channel switch. */
+ struct cfg80211_beacon_data *next_beacon;
struct list_head vlans;
struct ps_data ps;
@@ -716,6 +718,11 @@ struct ieee80211_sub_if_data {
struct ieee80211_tx_queue_params tx_conf[IEEE80211_NUM_ACS];
+ struct work_struct csa_finalize_work;
+ int csa_counter_offset_beacon;
+ int csa_counter_offset_presp;
+ bool csa_radar_required;
+
/* used to reconfigure hardware SM PS */
struct work_struct recalc_smps;
@@ -1373,6 +1380,9 @@ void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc, bool free);
void ieee80211_sw_roc_work(struct work_struct *work);
void ieee80211_handle_roc_started(struct ieee80211_roc_work *roc);
+/* channel switch handling */
+void ieee80211_csa_finalize_work(struct work_struct *work);
+
/* interface handling */
int ieee80211_iface_init(void);
void ieee80211_iface_exit(void);
@@ -1394,6 +1404,9 @@ void ieee80211_del_virtual_monitor(struct ieee80211_local *local);
bool __ieee80211_recalc_txpower(struct ieee80211_sub_if_data *sdata);
void ieee80211_recalc_txpower(struct ieee80211_sub_if_data *sdata);
+int ieee80211_assign_beacon(struct ieee80211_sub_if_data *sdata,
+ struct cfg80211_beacon_data *params);
+
static inline bool ieee80211_sdata_running(struct ieee80211_sub_if_data *sdata)
{
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 093c34a..187c161 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -274,6 +274,12 @@ static int ieee80211_check_concurrent_iface(struct ieee80211_sub_if_data *sdata,
if (iftype == NL80211_IFTYPE_ADHOC &&
nsdata->vif.type == NL80211_IFTYPE_ADHOC)
return -EBUSY;
+ /*
+ * will not add another interface while any channel
+ * switch is active.
+ */
+ if (nsdata->vif.csa_active)
+ return -EBUSY;
/*
* The remaining checks are only performed for interfaces
@@ -804,6 +810,8 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
cancel_work_sync(&local->dynamic_ps_enable_work);
cancel_work_sync(&sdata->recalc_smps);
+ sdata->vif.csa_active = false;
+ cancel_work_sync(&sdata->csa_finalize_work);
cancel_delayed_work_sync(&sdata->dfs_cac_timer_work);
@@ -1267,6 +1275,7 @@ static void ieee80211_setup_sdata(struct ieee80211_sub_if_data *sdata,
skb_queue_head_init(&sdata->skb_queue);
INIT_WORK(&sdata->work, ieee80211_iface_work);
INIT_WORK(&sdata->recalc_smps, ieee80211_recalc_smps_work);
+ INIT_WORK(&sdata->csa_finalize_work, ieee80211_csa_finalize_work);
switch (type) {
case NL80211_IFTYPE_P2P_GO:
diff --git a/net/mac80211/trace.h b/net/mac80211/trace.h
index c215fafd7..1aba645 100644
--- a/net/mac80211/trace.h
+++ b/net/mac80211/trace.h
@@ -1906,6 +1906,32 @@ TRACE_EVENT(api_radar_detected,
)
);
+TRACE_EVENT(drv_channel_switch_beacon,
+ TP_PROTO(struct ieee80211_local *local,
+ struct ieee80211_sub_if_data *sdata,
+ struct cfg80211_chan_def *chandef),
+
+ TP_ARGS(local, sdata, chandef),
+
+ TP_STRUCT__entry(
+ LOCAL_ENTRY
+ VIF_ENTRY
+ CHANDEF_ENTRY
+ ),
+
+ TP_fast_assign(
+ LOCAL_ASSIGN;
+ VIF_ASSIGN;
+ CHANDEF_ASSIGN(chandef);
+ ),
+
+ TP_printk(
+ LOCAL_PR_FMT VIF_PR_FMT " channel switch to " CHANDEF_PR_FMT,
+ LOCAL_PR_ARG, VIF_PR_ARG, CHANDEF_PR_ARG
+ )
+);
+
+
#ifdef CONFIG_MAC80211_MESSAGE_TRACING
#undef TRACE_SYSTEM
#define TRACE_SYSTEM mac80211_msg
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index f82301b..1da252a 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -2335,6 +2335,83 @@ static int ieee80211_beacon_add_tim(struct ieee80211_sub_if_data *sdata,
return 0;
}
+void ieee80211_csa_finish(struct ieee80211_vif *vif)
+{
+ struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+
+ vif->csa_active = false;
+ ieee80211_queue_work(&sdata->local->hw,
+ &sdata->csa_finalize_work);
+}
+EXPORT_SYMBOL(ieee80211_csa_finish);
+
+static void ieee80211_update_csa(struct ieee80211_sub_if_data *sdata,
+ struct beacon_data *beacon)
+{
+ struct probe_resp *resp;
+ int counter_offset_beacon = sdata->csa_counter_offset_beacon;
+ int counter_offset_presp = sdata->csa_counter_offset_presp;
+
+ /* warn if the driver did not check for/react to csa completeness */
+ if (WARN_ON(((u8 *)beacon->tail)[counter_offset_beacon] == 0))
+ return;
+
+ ((u8 *)beacon->tail)[counter_offset_beacon]--;
+
+ if (!counter_offset_presp)
+ return;
+
+ if (sdata->vif.type == NL80211_IFTYPE_AP) {
+ rcu_read_lock();
+ resp = rcu_dereference(sdata->u.ap.probe_resp);
+
+ /* if nl80211 accepted the offset, this should not happen. */
+ if (WARN_ON(!resp)) {
+ rcu_read_unlock();
+ return;
+ }
+ resp->data[counter_offset_presp]--;
+ }
+}
+
+bool ieee80211_csa_is_complete(struct ieee80211_vif *vif)
+{
+ struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+ struct beacon_data *beacon = NULL;
+ u8 *beacon_data;
+ size_t beacon_data_len;
+ int counter_beacon = sdata->csa_counter_offset_beacon;
+ int ret = false;
+
+ if (!ieee80211_sdata_running(sdata))
+ return false;
+
+ rcu_read_lock();
+ if (vif->type == NL80211_IFTYPE_AP) {
+ struct ieee80211_if_ap *ap = &sdata->u.ap;
+
+ beacon = rcu_dereference(ap->beacon);
+ if (WARN_ON(!beacon || !beacon->tail))
+ goto out;
+ beacon_data = beacon->tail;
+ beacon_data_len = beacon->tail_len;
+ } else {
+ WARN_ON(1);
+ goto out;
+ }
+
+ if (WARN_ON(counter_beacon > beacon_data_len))
+ goto out;
+
+ if (beacon_data[counter_beacon] == 0)
+ ret = true;
+ out:
+ rcu_read_unlock();
+
+ return ret;
+}
+EXPORT_SYMBOL(ieee80211_csa_is_complete);
+
struct sk_buff *ieee80211_beacon_get_tim(struct ieee80211_hw *hw,
struct ieee80211_vif *vif,
u16 *tim_offset, u16 *tim_length)
@@ -2365,6 +2442,9 @@ struct sk_buff *ieee80211_beacon_get_tim(struct ieee80211_hw *hw,
struct beacon_data *beacon = rcu_dereference(ap->beacon);
if (beacon) {
+ if (sdata->vif.csa_active)
+ ieee80211_update_csa(sdata, beacon);
+
/*
* headroom, head length,
* tail length and maximum TIM length
--
1.7.10.4
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