To use DFS in IBSS mode, userspace is required to react to radar events.
It can inform nl80211 that it is capable of doing so by adding a
NL80211_ATTR_CONTROL_PORT_DFS attribute when joining the IBSS.
If this attribute is supplied, DFS channels may be used if the driver
supports it. Support will be checked even if a channel without DFS will
be joined, as the channel might change later due to scan activity or
channel switch announcements.
Signed-off-by: Simon Wunderlich <siwu@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@xxxxxxxxxxxxxxxxxxx>
---
include/net/cfg80211.h | 6 ++++++
include/uapi/linux/nl80211.h | 7 +++++++
net/wireless/chan.c | 3 ++-
net/wireless/ibss.c | 24 ++++++++++++++++++++----
net/wireless/nl80211.c | 8 ++++++--
net/wireless/util.c | 11 +++++++++--
6 files changed, 50 insertions(+), 9 deletions(-)
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 0a2aafe..b20e8ca 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1656,6 +1656,9 @@ struct cfg80211_disassoc_request {
* sets/clears %NL80211_STA_FLAG_AUTHORIZED. If true, the driver is
* required to assume that the port is unauthorized until authorized by
* user space. Otherwise, port is marked authorized by default.
+ * @control_port_dfs: whether user space controls DFS operation, i.e.
+ * changes the channel when a radar is detected. This is required
+ * to operate on DFS channels.
* @basic_rates: bitmap of basic rates to use when creating the IBSS
* @mcast_rate: per-band multicast rate index + 1 (0: disabled)
* @ht_capa: HT Capabilities over-rides. Values set in ht_capa_mask
@@ -1673,6 +1676,7 @@ struct cfg80211_ibss_params {
bool channel_fixed;
bool privacy;
bool control_port;
+ bool control_port_dfs;
int mcast_rate[IEEE80211_NUM_BANDS];
struct ieee80211_ht_cap ht_capa;
struct ieee80211_ht_cap ht_capa_mask;
@@ -3053,6 +3057,7 @@ struct cfg80211_cached_keys;
* @conn: (private) cfg80211 software SME connection state machine data
* @connect_keys: (private) keys to set after connection is established
* @ibss_fixed: (private) IBSS is using fixed BSSID
+ * @ibss_dfs_possible: (private) IBSS may change to a DFS channel
* @event_list: (private) list for internal event processing
* @event_lock: (private) lock for event list
*/
@@ -3091,6 +3096,7 @@ struct wireless_dev {
struct ieee80211_channel *channel;
bool ibss_fixed;
+ bool ibss_dfs_possible;
bool ps;
int ps_timeout;
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index fde2c02..80e68e0 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -1496,6 +1496,11 @@ enum nl80211_commands {
* @NL80211_ATTR_RXMGMT_FLAGS: flags for nl80211_send_mgmt(), u32.
* As specified in the &enum nl80211_rxmgmt_flags.
*
+ * @NL80211_ATTR_CONTROL_PORT_DFS: A flag indicating whether user space
+ * controls DFS operation in IBSS mode. If the flag is included in
+ * %NL80211_CMD_JOIN_IBSS request, the driver will allow use of DFS
+ * channels and reports radar events to userspace.
+ *
* @NL80211_ATTR_MAX: highest attribute number currently defined
* @__NL80211_ATTR_AFTER_LAST: internal use
*/
@@ -1806,6 +1811,8 @@ enum nl80211_attrs {
NL80211_ATTR_RXMGMT_FLAGS,
+ NL80211_ATTR_CONTROL_PORT_DFS,
+
/* add attributes here, update the policy in nl80211.c */
__NL80211_ATTR_AFTER_LAST,
diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index 80504e6..92cf75f 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -504,7 +504,8 @@ cfg80211_get_chan_state(struct wireless_dev *wdev,
case NL80211_IFTYPE_ADHOC:
if (wdev->current_bss) {
*chan = wdev->current_bss->pub.channel;
- *chanmode = wdev->ibss_fixed
+ *chanmode = (wdev->ibss_fixed &&
+ !wdev->ibss_dfs_possible)
? CHAN_MODE_SHARED
: CHAN_MODE_EXCLUSIVE;
return;
diff --git a/net/wireless/ibss.c b/net/wireless/ibss.c
index 39bff7d..5edd69e 100644
--- a/net/wireless/ibss.c
+++ b/net/wireless/ibss.c
@@ -83,6 +83,8 @@ int __cfg80211_join_ibss(struct cfg80211_registered_device *rdev,
struct cfg80211_cached_keys *connkeys)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
+ struct ieee80211_channel *check_chan;
+ u8 radar_detect_width = 0;
int err;
ASSERT_WDEV_LOCK(wdev);
@@ -114,14 +116,28 @@ int __cfg80211_join_ibss(struct cfg80211_registered_device *rdev,
wdev->connect_keys = connkeys;
wdev->ibss_fixed = params->channel_fixed;
+ wdev->ibss_dfs_possible = params->control_port_dfs;
#ifdef CONFIG_CFG80211_WEXT
wdev->wext.ibss.chandef = params->chandef;
#endif
+ check_chan = params->chandef.chan;
+ if (params->control_port_dfs) {
+ /* use channel NULL to check for radar even if the current
+ * channel is not a radar channel - it might decide to change
+ * to DFS channel later.
+ */
+ radar_detect_width = BIT(params->chandef.width);
+ check_chan = NULL;
+ }
+
+ err = cfg80211_can_use_iftype_chan(rdev, wdev, wdev->iftype,
+ check_chan,
+ (params->channel_fixed &&
+ !radar_detect_width)
+ ? CHAN_MODE_SHARED
+ : CHAN_MODE_EXCLUSIVE,
+ radar_detect_width);
- err = cfg80211_can_use_chan(rdev, wdev, params->chandef.chan,
- params->channel_fixed
- ? CHAN_MODE_SHARED
- : CHAN_MODE_EXCLUSIVE);
if (err) {
wdev->connect_keys = NULL;
return err;
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index cbbef88..d10410a 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -354,6 +354,7 @@ static const struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] = {
[NL80211_ATTR_CSA_IES] = { .type = NLA_NESTED },
[NL80211_ATTR_CSA_C_OFF_BEACON] = { .type = NLA_U16 },
[NL80211_ATTR_CSA_C_OFF_PRESP] = { .type = NLA_U16 },
+ [NL80211_ATTR_CONTROL_PORT_DFS] = { .type = NLA_FLAG },
};
/* policy for the key attributes */
@@ -5722,9 +5723,9 @@ skip_beacons:
if (!cfg80211_reg_can_beacon(&rdev->wiphy, ¶ms.chandef))
return -EINVAL;
- /* DFS channels are only supported for AP/P2P GO ... for now. */
if (dev->ieee80211_ptr->iftype == NL80211_IFTYPE_AP ||
- dev->ieee80211_ptr->iftype == NL80211_IFTYPE_P2P_GO) {
+ dev->ieee80211_ptr->iftype == NL80211_IFTYPE_P2P_GO ||
+ dev->ieee80211_ptr->iftype == NL80211_IFTYPE_ADHOC) {
err = cfg80211_chandef_dfs_required(wdev->wiphy,
¶ms.chandef);
if (err < 0) {
@@ -6556,6 +6557,9 @@ static int nl80211_join_ibss(struct sk_buff *skb, struct genl_info *info)
ibss.control_port =
nla_get_flag(info->attrs[NL80211_ATTR_CONTROL_PORT]);
+ ibss.control_port_dfs =
+ nla_get_flag(info->attrs[NL80211_ATTR_CONTROL_PORT_DFS]);
+
err = cfg80211_join_ibss(rdev, dev, &ibss, connkeys);
if (err)
kfree(connkeys);
diff --git a/net/wireless/util.c b/net/wireless/util.c
index ce090c1..beee988 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -1255,8 +1255,15 @@ int cfg80211_can_use_iftype_chan(struct cfg80211_registered_device *rdev,
case NL80211_IFTYPE_MESH_POINT:
case NL80211_IFTYPE_P2P_GO:
case NL80211_IFTYPE_WDS:
- radar_required = !!(chan &&
- (chan->flags & IEEE80211_CHAN_RADAR));
+ /* if the interface could potentially choose a DFS channel,
+ * then mark DFS as required.
+ */
+ if (!chan) {
+ if (chanmode != CHAN_MODE_UNDEFINED && radar_detect)
+ radar_required = true;
+ break;
+ }
+ radar_required = !!(chan->flags & IEEE80211_CHAN_RADAR);
break;
case NL80211_IFTYPE_P2P_CLIENT:
case NL80211_IFTYPE_STATION:
--
1.7.10.4
--
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