v6 of these patches incorporate more changes based on of Johannes' comments.
Some parts of the code was refactored to improve extendability.
v6 also has fixes a problem in configuring the rssi threshold and hysteresis
to the driver. It's now only done when associated.
To implement good performance WLAN roaming, it is not sufficient to start
scanning for other available AP's only after the currently serving association
is lost.
The entity controlling the roaming will need to get indication of a
deteriorating WLAN connection in order to start preparing for roaming already
before the serving association is lost. This way, it can roam to a better AP
perhaps even before the serving association becomes too bad in quality.
These patches propose an implementation facilitating this using a simple RSSI
threshold and hysteresis approach.
These patches add a nl80211 interface for simply configuring a rssi threshold
and hysteresis value to facilitate very basic connection quality monitoring.
For the triggering, these patches currently rely on HW support, host based
triggering is not implemented, but could be added later if needed.
These patches have been tested with the wl1271 driver.
Thanks in advance for your comments and suggestions.
Juuso Oikarinen (2):
cfg80211: Add connection quality monitoring support to nl80211
mac80211: Add support for connection quality monitoring
include/linux/nl80211.h | 46 ++++++++++++++++
include/net/cfg80211.h | 19 +++++++
include/net/mac80211.h | 29 ++++++++++
net/mac80211/cfg.c | 27 ++++++++++
net/mac80211/mlme.c | 15 +++++
net/wireless/mlme.c | 13 +++++
net/wireless/nl80211.c | 131 +++++++++++++++++++++++++++++++++++++++++++++++
net/wireless/nl80211.h | 6 ++
8 files changed, 286 insertions(+), 0 deletions(-)
Add support for basic configuration of a connection quality monitoring to the
nl80211 interface, and basic support for notifying about triggered monitoring
events.
Via this interface a user-space connection manager may configure and receive
pre-warning events of deteriorating WLAN connection quality, and start
preparing for roaming in advance, before the connection is already lost.
An example usage of such a trigger is starting scanning for nearby AP's in
an attempt to find one with better connection quality, and associate to it
before the connection characteristics of the existing connection become too bad
or the association is even lost, leading in a prolonged delay in connectivity.
The interface currently supports only RSSI, but it could be later extended
to include other parameters, such as signal-to-noise ratio, if need for that
arises.
Signed-off-by: Juuso Oikarinen <[email protected]>
---
include/linux/nl80211.h | 46 ++++++++++++++++
include/net/cfg80211.h | 19 +++++++
net/wireless/mlme.c | 13 +++++
net/wireless/nl80211.c | 131 +++++++++++++++++++++++++++++++++++++++++++++++
net/wireless/nl80211.h | 6 ++
5 files changed, 215 insertions(+), 0 deletions(-)
diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index 28ba20f..8994759 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -323,6 +323,12 @@
* the TX command and %NL80211_ATTR_FRAME includes the contents of the
* frame. %NL80211_ATTR_ACK flag is included if the recipient acknowledged
* the frame.
+ * @NL80211_CMD_SET_CQM: Connection quality monitor configuration. This command
+ * is used to configure connection quality monitoring notification trigger
+ * levels.
+ * @NL80211_CMD_NOTIFY_CQM: Connection quality monitor notification. This
+ * command is used as an event to indicate the that a trigger level was
+ * reached.
*
* @NL80211_CMD_MAX: highest used command number
* @__NL80211_CMD_AFTER_LAST: internal use
@@ -419,6 +425,9 @@ enum nl80211_commands {
NL80211_CMD_SET_POWER_SAVE,
NL80211_CMD_GET_POWER_SAVE,
+ NL80211_CMD_SET_CQM,
+ NL80211_CMD_NOTIFY_CQM,
+
/* add new commands above here */
/* used to define NL80211_CMD_MAX below */
@@ -691,6 +700,9 @@ enum nl80211_commands {
* @NL80211_ATTR_ACK: Flag attribute indicating that the frame was
* acknowledged by the recipient.
*
+ * @NL80211_ATTR_CQM: connection quality monitor configuration in a
+ * nested attribute with %NL80211_ATTR_CQM_* sub-attributes.
+ *
* @NL80211_ATTR_MAX: highest attribute number currently defined
* @__NL80211_ATTR_AFTER_LAST: internal use
*/
@@ -842,6 +854,8 @@ enum nl80211_attrs {
NL80211_ATTR_PS_STATE,
+ NL80211_ATTR_CQM,
+
/* add attributes here, update the policy in nl80211.c */
__NL80211_ATTR_AFTER_LAST,
@@ -1583,4 +1597,36 @@ enum nl80211_ps_state {
NL80211_PS_ENABLED,
};
+/**
+ * enum nl80211_attr_cqm - connection quality monitor attributes
+ * @__NL80211_ATTR_CQM_INVALID: invalid
+ * @NL80211_ATTR_CQM_RSSI_THOLD: RSSI threshold in dBm (zero to disable)
+ * @NL80211_ATTR_CQM_RSSI_HYST: RSSI hysteresis in dBm
+ * @NL80211_ATTR_CQM_RSSI_THRESHOLD_EVENT: RSSI threshold event
+ * @__NL80211_ATTR_CQM_AFTER_LAST: internal
+ * @NL80211_ATTR_CQM_MAX: highest key attribute
+ */
+enum nl80211_attr_cqm {
+ __NL80211_ATTR_CQM_INVALID,
+ NL80211_ATTR_CQM_RSSI_THOLD,
+ NL80211_ATTR_CQM_RSSI_HYST,
+ NL80211_ATTR_CQM_RSSI_THRESHOLD_EVENT,
+
+ /* keep last */
+ __NL80211_ATTR_CQM_AFTER_LAST,
+ NL80211_ATTR_CQM_MAX = __NL80211_ATTR_CQM_AFTER_LAST - 1
+};
+
+/**
+ * enum nl80211_cqm_rssi_threshold_event - RSSI threshold event
+ * @NL80211_CQM_RSSI_THRESHOLD_EVENT_LOW - The RSSI level is lower than the
+ * configured threshold
+ * @NL80211_CQM_RSSI_THRESHOLD_EVENT_HIGH - The RSSI is higher than the
+ * configured threshold
+ */
+enum nl80211_cqm_rssi_threshold_event {
+ NL80211_CQM_RSSI_THRESHOLD_EVENT_LOW,
+ NL80211_CQM_RSSI_THRESHOLD_EVENT_HIGH,
+};
+
#endif /* __LINUX_NL80211_H */
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 3d134a1..868cfd3 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1007,6 +1007,7 @@ struct cfg80211_pmksa {
* RSN IE. It allows for faster roaming between WPA2 BSSIDs.
* @del_pmksa: Delete a cached PMKID.
* @flush_pmksa: Flush all cached PMKIDs.
+ * @set_cqm_rssi_config: Configure connection quality monitor RSSI threshold.
*
*/
struct cfg80211_ops {
@@ -1152,6 +1153,10 @@ struct cfg80211_ops {
int (*set_power_mgmt)(struct wiphy *wiphy, struct net_device *dev,
bool enabled, int timeout);
+
+ int (*set_cqm_rssi_config)(struct wiphy *wiphy,
+ struct net_device *dev,
+ s32 rssi_thold, u32 rssi_hyst);
};
/*
@@ -2337,4 +2342,18 @@ bool cfg80211_rx_action(struct net_device *dev, int freq, const u8 *buf,
void cfg80211_action_tx_status(struct net_device *dev, u64 cookie,
const u8 *buf, size_t len, bool ack, gfp_t gfp);
+
+/**
+ * cfg80211_cqm_rssi_notify - connection quality monitoring rssi event
+ * @dev: network device
+ * @rssi_event: the triggered RSSI event
+ * @gfp: context flags
+ *
+ * This function is called when a configured connection quality monitoring
+ * rssi threshold reached event occurs.
+ */
+void cfg80211_cqm_rssi_notify(struct net_device *dev,
+ enum nl80211_cqm_rssi_threshold_event rssi_event,
+ gfp_t gfp);
+
#endif /* __NET_CFG80211_H */
diff --git a/net/wireless/mlme.c b/net/wireless/mlme.c
index 62bc885..0855f0d 100644
--- a/net/wireless/mlme.c
+++ b/net/wireless/mlme.c
@@ -894,3 +894,16 @@ void cfg80211_action_tx_status(struct net_device *dev, u64 cookie,
nl80211_send_action_tx_status(rdev, dev, cookie, buf, len, ack, gfp);
}
EXPORT_SYMBOL(cfg80211_action_tx_status);
+
+void cfg80211_cqm_rssi_notify(struct net_device *dev,
+ enum nl80211_cqm_rssi_threshold_event rssi_event,
+ gfp_t gfp)
+{
+ struct wireless_dev *wdev = dev->ieee80211_ptr;
+ struct wiphy *wiphy = wdev->wiphy;
+ struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);
+
+ /* Indicate roaming trigger event to user space */
+ nl80211_send_cqm_rssi_notify(rdev, dev, rssi_event, gfp);
+}
+EXPORT_SYMBOL(cfg80211_cqm_rssi_notify);
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index e447db0..a7fc3d8 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -149,6 +149,7 @@ static const struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] = {
.len = IEEE80211_MAX_DATA_LEN },
[NL80211_ATTR_FRAME_MATCH] = { .type = NLA_BINARY, },
[NL80211_ATTR_PS_STATE] = { .type = NLA_U32 },
+ [NL80211_ATTR_CQM] = { .type = NLA_NESTED, },
};
/* policy for the attributes */
@@ -4778,6 +4779,84 @@ unlock_rtnl:
return err;
}
+static struct nla_policy
+nl80211_attr_cqm_policy[NL80211_ATTR_CQM_MAX + 1] __read_mostly = {
+ [NL80211_ATTR_CQM_RSSI_THOLD] = { .type = NLA_U32 },
+ [NL80211_ATTR_CQM_RSSI_HYST] = { .type = NLA_U32 },
+ [NL80211_ATTR_CQM_RSSI_THRESHOLD_EVENT] = { .type = NLA_U32 },
+};
+
+static int nl80211_set_cqm_rssi(struct genl_info *info,
+ s32 threshold, u32 hysteresis)
+{
+ struct cfg80211_registered_device *rdev;
+ struct wireless_dev *wdev;
+ struct net_device *dev;
+ int err;
+
+ if (threshold > 0)
+ return -EINVAL;
+
+ rtnl_lock();
+
+ err = get_rdev_dev_by_info_ifindex(info, &rdev, &dev);
+ if (err)
+ goto unlock_rdev;
+
+ wdev = dev->ieee80211_ptr;
+
+ if (!rdev->ops->set_cqm_rssi_config) {
+ err = -EOPNOTSUPP;
+ goto unlock_rdev;
+ }
+
+ if (wdev->iftype != NL80211_IFTYPE_STATION) {
+ err = -EOPNOTSUPP;
+ goto unlock_rdev;
+ }
+
+ err = rdev->ops->set_cqm_rssi_config(wdev->wiphy, dev,
+ threshold, hysteresis);
+
+unlock_rdev:
+ cfg80211_unlock_rdev(rdev);
+ dev_put(dev);
+ rtnl_unlock();
+
+ return err;
+}
+
+static int nl80211_set_cqm(struct sk_buff *skb, struct genl_info *info)
+{
+ struct nlattr *attrs[NL80211_ATTR_CQM_MAX + 1];
+ struct nlattr *cqm;
+ int err;
+
+ cqm = info->attrs[NL80211_ATTR_CQM];
+ if (!cqm) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ err = nla_parse_nested(attrs, NL80211_ATTR_CQM_MAX, cqm,
+ nl80211_attr_cqm_policy);
+ if (err)
+ goto out;
+
+ if (attrs[NL80211_ATTR_CQM_RSSI_THOLD] &&
+ attrs[NL80211_ATTR_CQM_RSSI_HYST]) {
+ s32 threshold;
+ u32 hysteresis;
+ threshold = nla_get_u32(attrs[NL80211_ATTR_CQM_RSSI_THOLD]);
+ hysteresis = nla_get_u32(attrs[NL80211_ATTR_CQM_RSSI_HYST]);
+ err = nl80211_set_cqm_rssi(info, threshold, hysteresis);
+ } else
+ err = -EINVAL;
+
+out:
+ return err;
+}
+
static struct genl_ops nl80211_ops[] = {
{
.cmd = NL80211_CMD_GET_WIPHY,
@@ -5082,6 +5161,12 @@ static struct genl_ops nl80211_ops[] = {
.policy = nl80211_policy,
/* can be retrieved by unprivileged users */
},
+ {
+ .cmd = NL80211_CMD_SET_CQM,
+ .doit = nl80211_set_cqm,
+ .policy = nl80211_policy,
+ .flags = GENL_ADMIN_PERM,
+ },
};
static struct genl_multicast_group nl80211_mlme_mcgrp = {
@@ -5832,6 +5917,52 @@ void nl80211_send_action_tx_status(struct cfg80211_registered_device *rdev,
nlmsg_free(msg);
}
+void
+nl80211_send_cqm_rssi_notify(struct cfg80211_registered_device *rdev,
+ struct net_device *netdev,
+ enum nl80211_cqm_rssi_threshold_event rssi_event,
+ gfp_t gfp)
+{
+ struct sk_buff *msg;
+ struct nlattr *pinfoattr;
+ void *hdr;
+
+ msg = nlmsg_new(NLMSG_GOODSIZE, gfp);
+ if (!msg)
+ return;
+
+ hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_NOTIFY_CQM);
+ if (!hdr) {
+ nlmsg_free(msg);
+ return;
+ }
+
+ NLA_PUT_U32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx);
+ NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, netdev->ifindex);
+
+ pinfoattr = nla_nest_start(msg, NL80211_ATTR_CQM);
+ if (!pinfoattr)
+ goto nla_put_failure;
+
+ NLA_PUT_U32(msg, NL80211_ATTR_CQM_RSSI_THRESHOLD_EVENT,
+ rssi_event);
+
+ nla_nest_end(msg, pinfoattr);
+
+ if (genlmsg_end(msg, hdr) < 0) {
+ nlmsg_free(msg);
+ return;
+ }
+
+ genlmsg_multicast_netns(wiphy_net(&rdev->wiphy), msg, 0,
+ nl80211_mlme_mcgrp.id, gfp);
+ return;
+
+ nla_put_failure:
+ genlmsg_cancel(msg, hdr);
+ nlmsg_free(msg);
+}
+
static int nl80211_netlink_notify(struct notifier_block * nb,
unsigned long state,
void *_notify)
diff --git a/net/wireless/nl80211.h b/net/wireless/nl80211.h
index 4ca5111..2ad7fbc 100644
--- a/net/wireless/nl80211.h
+++ b/net/wireless/nl80211.h
@@ -82,4 +82,10 @@ void nl80211_send_action_tx_status(struct cfg80211_registered_device *rdev,
const u8 *buf, size_t len, bool ack,
gfp_t gfp);
+void
+nl80211_send_cqm_rssi_notify(struct cfg80211_registered_device *rdev,
+ struct net_device *netdev,
+ enum nl80211_cqm_rssi_threshold_event rssi_event,
+ gfp_t gfp);
+
#endif /* __NET_WIRELESS_NL80211_H */
--
1.6.3.3
On Mon, 2010-03-22 at 19:28 +0100, ext Johannes Berg wrote:
> On Mon, 2010-03-22 at 12:15 +0200, Juuso Oikarinen wrote:
> > v6 of these patches incorporate more changes based on of Johannes' comments.
> > Some parts of the code was refactored to improve extendability.
> >
> > v6 also has fixes a problem in configuring the rssi threshold and hysteresis
> > to the driver. It's now only done when associated.
>
> I like it now :)
>
> Reviewed-by: Johannes Berg <[email protected]>
Thanks a lot for your effort on this! I too believe it's way better than
what I started out with.
-Juuso
> johannes
>
Add support for the set_cqm_config op. This op function configures the
requested connection quality monitor rssi threshold and rssi hysteresis
values to the hardware if the hardware supports
IEEE80211_HW_SUPPORTS_CQM.
For unsupporting hardware, currently -EOPNOTSUPP is returned, so the mac80211
is currently not doing connection quality monitoring on the host. This could be
added later, if needed.
Signed-off-by: Juuso Oikarinen <[email protected]>
---
include/net/mac80211.h | 29 +++++++++++++++++++++++++++++
net/mac80211/cfg.c | 27 +++++++++++++++++++++++++++
net/mac80211/mlme.c | 15 +++++++++++++++
3 files changed, 71 insertions(+), 0 deletions(-)
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 936bc41..40e23f3 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -144,6 +144,7 @@ struct ieee80211_low_level_stats {
* new beacon (beaconing modes)
* @BSS_CHANGED_BEACON_ENABLED: Beaconing should be
* enabled/disabled (beaconing modes)
+ * @BSS_CHANGED_CQM: Connection quality monitor config changed
*/
enum ieee80211_bss_change {
BSS_CHANGED_ASSOC = 1<<0,
@@ -156,6 +157,7 @@ enum ieee80211_bss_change {
BSS_CHANGED_BSSID = 1<<7,
BSS_CHANGED_BEACON = 1<<8,
BSS_CHANGED_BEACON_ENABLED = 1<<9,
+ BSS_CHANGED_CQM = 1<<10,
};
/**
@@ -185,6 +187,9 @@ enum ieee80211_bss_change {
* @enable_beacon: whether beaconing should be enabled or not
* @ht_operation_mode: HT operation mode (like in &struct ieee80211_ht_info).
* This field is only valid when the channel type is one of the HT types.
+ * @cqm_rssi_thold: Connection quality monitor RSSI threshold, a zero value
+ * implies disabled
+ * @cqm_rssi_hyst: Connection quality monitor RSSI hysteresis
*/
struct ieee80211_bss_conf {
const u8 *bssid;
@@ -202,6 +207,8 @@ struct ieee80211_bss_conf {
u64 timestamp;
u32 basic_rates;
u16 ht_operation_mode;
+ s32 cqm_rssi_thold;
+ u32 cqm_rssi_hyst;
};
/**
@@ -954,6 +961,11 @@ enum ieee80211_tkip_key_type {
* Hardware can provide ack status reports of Tx frames to
* the stack.
*
+ * @IEEE80211_HW_SUPPORTS_CQM_RSSI:
+ * Hardware can do connection quality monitoring - i.e. it can monitor
+ * connection quality related parameters, such as the RSSI level and
+ * provide notifications if configured trigger levels are reached.
+ *
*/
enum ieee80211_hw_flags {
IEEE80211_HW_HAS_RATE_CONTROL = 1<<0,
@@ -975,6 +987,7 @@ enum ieee80211_hw_flags {
IEEE80211_HW_SUPPORTS_DYNAMIC_SMPS = 1<<16,
IEEE80211_HW_SUPPORTS_UAPSD = 1<<17,
IEEE80211_HW_REPORTS_TX_ACK_STATUS = 1<<18,
+ IEEE80211_HW_SUPPORTS_CQM_RSSI = 1<<19,
};
/**
@@ -2370,6 +2383,22 @@ void ieee80211_sta_block_awake(struct ieee80211_hw *hw,
*/
void ieee80211_beacon_loss(struct ieee80211_vif *vif);
+/**
+ * ieee80211_cqm_rssi_notify - inform a configured connection quality monitoring
+ * rssi threshold triggered
+ *
+ * @vif: &struct ieee80211_vif pointer from the add_interface callback.
+ * @rssi_event: the RSSI trigger event type
+ * @gfp: context flags
+ *
+ * When the %IEEE80211_HW_SUPPORTS_CQM_RSSI is set, and a connection quality
+ * monitoring is configured with an rssi threshold, the driver will inform
+ * whenever the rssi level reaches the threshold.
+ */
+void ieee80211_cqm_rssi_notify(struct ieee80211_vif *vif,
+ enum nl80211_cqm_rssi_threshold_event rssi_event,
+ gfp_t gfp);
+
/* Rate control API */
/**
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index b7116ef..c8f5205 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1402,6 +1402,32 @@ static int ieee80211_set_power_mgmt(struct wiphy *wiphy, struct net_device *dev,
return 0;
}
+static int ieee80211_set_cqm_rssi_config(struct wiphy *wiphy,
+ struct net_device *dev,
+ s32 rssi_thold, u32 rssi_hyst)
+{
+ struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+ struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
+ struct ieee80211_vif *vif = &sdata->vif;
+ struct ieee80211_bss_conf *bss_conf = &vif->bss_conf;
+
+ if (!(local->hw.flags & IEEE80211_HW_SUPPORTS_CQM_RSSI))
+ return -EOPNOTSUPP;
+
+ if (rssi_thold == bss_conf->cqm_rssi_thold &&
+ rssi_hyst == bss_conf->cqm_rssi_hyst)
+ return 0;
+
+ bss_conf->cqm_rssi_thold = rssi_thold;
+ bss_conf->cqm_rssi_hyst = rssi_hyst;
+
+ /* tell the driver upon association, unless already associated */
+ if (sdata->u.mgd.associated)
+ ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_CQM);
+
+ return 0;
+}
+
static int ieee80211_set_bitrate_mask(struct wiphy *wiphy,
struct net_device *dev,
const u8 *addr,
@@ -1506,4 +1532,5 @@ struct cfg80211_ops mac80211_config_ops = {
.remain_on_channel = ieee80211_remain_on_channel,
.cancel_remain_on_channel = ieee80211_cancel_remain_on_channel,
.action = ieee80211_action,
+ .set_cqm_rssi_config = ieee80211_set_cqm_rssi_config,
};
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index be5f723..5927077 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -753,6 +753,11 @@ static void ieee80211_set_associated(struct ieee80211_sub_if_data *sdata,
/* And the BSSID changed - we're associated now */
bss_info_changed |= BSS_CHANGED_BSSID;
+ /* Tell the driver to monitor connection quality (if supported) */
+ if ((local->hw.flags & IEEE80211_HW_SUPPORTS_CQM_RSSI) &&
+ sdata->vif.bss_conf.cqm_rssi_thold)
+ bss_info_changed |= BSS_CHANGED_CQM;
+
ieee80211_bss_info_change_notify(sdata, bss_info_changed);
mutex_lock(&local->iflist_mtx);
@@ -2135,3 +2140,13 @@ int ieee80211_mgd_action(struct ieee80211_sub_if_data *sdata,
*cookie = (unsigned long) skb;
return 0;
}
+
+void ieee80211_cqm_rssi_notify(struct ieee80211_vif *vif,
+ enum nl80211_cqm_rssi_threshold_event rssi_event,
+ gfp_t gfp)
+{
+ struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+
+ cfg80211_cqm_rssi_notify(sdata->dev, rssi_event, gfp);
+}
+EXPORT_SYMBOL(ieee80211_cqm_rssi_notify);
--
1.6.3.3
On Mon, 2010-03-22 at 12:15 +0200, Juuso Oikarinen wrote:
> v6 of these patches incorporate more changes based on of Johannes' comments.
> Some parts of the code was refactored to improve extendability.
>
> v6 also has fixes a problem in configuring the rssi threshold and hysteresis
> to the driver. It's now only done when associated.
I like it now :)
Reviewed-by: Johannes Berg <[email protected]>
johannes