From: Johannes Berg <johannes.berg@xxxxxxxxx>
If the hardware supports a disabled channel, it may in
some cases be possible to use monitor mode (without any
transmit) on it when it's otherwise disabled. Add a new
channel flag IEEE80211_CHAN_CAN_MONITOR that makes it
possible for a driver to indicate such a thing.
Make it per channel so drivers could have a choice with
it, perhaps it's only possible on some channels, perhaps
some channels are not supported at all, but still there
and marked disabled.
In _nl80211_parse_chandef() simplify the code and check
only for an unknown channel, _cfg80211_chandef_usable()
will later check for IEEE80211_CHAN_DISABLED anyway.
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@xxxxxxxxx>
---
include/net/cfg80211.h | 4 ++++
include/uapi/linux/nl80211.h | 4 ++++
net/wireless/chan.c | 26 +++++++++++++++++++-------
net/wireless/core.h | 5 ++++-
net/wireless/nl80211.c | 27 ++++++++++++++++++---------
5 files changed, 49 insertions(+), 17 deletions(-)
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index bac3d75ccded..69e50bc2aa43 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -122,6 +122,9 @@ struct wiphy;
* not permitted using this channel
* @IEEE80211_CHAN_NO_6GHZ_AFC_CLIENT: Client connection with AFC AP
* not permitted using this channel
+ * @IEEE80211_CHAN_CAN_MONITOR: This channel can be used for monitor
+ * mode even in the presence of other (regulatory) restrictions,
+ * even if it is otherwise disabled.
*/
enum ieee80211_channel_flags {
IEEE80211_CHAN_DISABLED = 1<<0,
@@ -148,6 +151,7 @@ enum ieee80211_channel_flags {
IEEE80211_CHAN_DFS_CONCURRENT = 1<<21,
IEEE80211_CHAN_NO_6GHZ_VLP_CLIENT = 1<<22,
IEEE80211_CHAN_NO_6GHZ_AFC_CLIENT = 1<<23,
+ IEEE80211_CHAN_CAN_MONITOR = 1<<24,
};
#define IEEE80211_CHAN_NO_HT40 \
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 2af018dfef39..0cac86d090c8 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -4272,6 +4272,9 @@ enum nl80211_wmm_rule {
* not allowed using this channel
* @NL80211_FREQUENCY_ATTR_NO_6GHZ_AFC_CLIENT: Client connection to AFC AP
* not allowed using this channel
+ * @NL80211_FREQUENCY_ATTR_CAN_MONITOR: This channel can be used in monitor
+ * mode despite other (regulatory) restrictions, even if the channel is
+ * otherwise completely disabled.
* @NL80211_FREQUENCY_ATTR_MAX: highest frequency attribute number
* currently defined
* @__NL80211_FREQUENCY_ATTR_AFTER_LAST: internal use
@@ -4314,6 +4317,7 @@ enum nl80211_frequency_attr {
NL80211_FREQUENCY_ATTR_DFS_CONCURRENT,
NL80211_FREQUENCY_ATTR_NO_6GHZ_VLP_CLIENT,
NL80211_FREQUENCY_ATTR_NO_6GHZ_AFC_CLIENT,
+ NL80211_FREQUENCY_ATTR_CAN_MONITOR,
/* keep last */
__NL80211_FREQUENCY_ATTR_AFTER_LAST,
diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index ceb9174c5c3d..1839a4827fce 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -1047,7 +1047,7 @@ EXPORT_SYMBOL(cfg80211_chandef_dfs_cac_time);
static bool cfg80211_secondary_chans_ok(struct wiphy *wiphy,
u32 center_freq, u32 bandwidth,
- u32 prohibited_flags)
+ u32 prohibited_flags, bool monitor)
{
struct ieee80211_channel *c;
u32 freq, start_freq, end_freq;
@@ -1057,7 +1057,11 @@ static bool cfg80211_secondary_chans_ok(struct wiphy *wiphy,
for (freq = start_freq; freq <= end_freq; freq += MHZ_TO_KHZ(20)) {
c = ieee80211_get_channel_khz(wiphy, freq);
- if (!c || c->flags & prohibited_flags)
+ if (!c)
+ return false;
+ if (monitor && c->flags & IEEE80211_CHAN_CAN_MONITOR)
+ continue;
+ if (c->flags & prohibited_flags)
return false;
}
@@ -1117,9 +1121,9 @@ static bool cfg80211_edmg_usable(struct wiphy *wiphy, u8 edmg_channels,
return true;
}
-bool cfg80211_chandef_usable(struct wiphy *wiphy,
- const struct cfg80211_chan_def *chandef,
- u32 prohibited_flags)
+bool _cfg80211_chandef_usable(struct wiphy *wiphy,
+ const struct cfg80211_chan_def *chandef,
+ u32 prohibited_flags, bool monitor)
{
struct ieee80211_sta_ht_cap *ht_cap;
struct ieee80211_sta_vht_cap *vht_cap;
@@ -1281,14 +1285,22 @@ bool cfg80211_chandef_usable(struct wiphy *wiphy,
if (!cfg80211_secondary_chans_ok(wiphy,
ieee80211_chandef_to_khz(chandef),
- width, prohibited_flags))
+ width, prohibited_flags, monitor))
return false;
if (!chandef->center_freq2)
return true;
return cfg80211_secondary_chans_ok(wiphy,
MHZ_TO_KHZ(chandef->center_freq2),
- width, prohibited_flags);
+ width, prohibited_flags, monitor);
+}
+
+bool cfg80211_chandef_usable(struct wiphy *wiphy,
+ const struct cfg80211_chan_def *chandef,
+ u32 prohibited_flags)
+{
+ return _cfg80211_chandef_usable(wiphy, chandef, prohibited_flags,
+ false);
}
EXPORT_SYMBOL(cfg80211_chandef_usable);
diff --git a/net/wireless/core.h b/net/wireless/core.h
index debf63e6c61f..118f2f619828 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -3,7 +3,7 @@
* Wireless configuration interface internals.
*
* Copyright 2006-2010 Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
- * Copyright (C) 2018-2023 Intel Corporation
+ * Copyright (C) 2018-2024 Intel Corporation
*/
#ifndef __NET_WIRELESS_CORE_H
#define __NET_WIRELESS_CORE_H
@@ -492,6 +492,9 @@ bool cfg80211_is_sub_chan(struct cfg80211_chan_def *chandef,
bool cfg80211_wdev_on_sub_chan(struct wireless_dev *wdev,
struct ieee80211_channel *chan,
bool primary_only);
+bool _cfg80211_chandef_usable(struct wiphy *wiphy,
+ const struct cfg80211_chan_def *chandef,
+ u32 prohibited_flags, bool monitor);
static inline unsigned int elapsed_jiffies_msecs(unsigned long start)
{
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 24d3b01cd000..40b4405d15bd 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -3233,9 +3233,9 @@ static int nl80211_parse_punct_bitmap(struct cfg80211_registered_device *rdev,
return 0;
}
-int nl80211_parse_chandef(struct cfg80211_registered_device *rdev,
- struct genl_info *info,
- struct cfg80211_chan_def *chandef)
+static int _nl80211_parse_chandef(struct cfg80211_registered_device *rdev,
+ struct genl_info *info, bool monitor,
+ struct cfg80211_chan_def *chandef)
{
struct netlink_ext_ack *extack = info->extack;
struct nlattr **attrs = info->attrs;
@@ -3260,10 +3260,9 @@ int nl80211_parse_chandef(struct cfg80211_registered_device *rdev,
chandef->freq1_offset = control_freq % 1000;
chandef->center_freq2 = 0;
- /* Primary channel not allowed */
- if (!chandef->chan || chandef->chan->flags & IEEE80211_CHAN_DISABLED) {
+ if (!chandef->chan) {
NL_SET_ERR_MSG_ATTR(extack, attrs[NL80211_ATTR_WIPHY_FREQ],
- "Channel is disabled");
+ "Unknown channel");
return -EINVAL;
}
@@ -3345,8 +3344,9 @@ int nl80211_parse_chandef(struct cfg80211_registered_device *rdev,
return -EINVAL;
}
- if (!cfg80211_chandef_usable(&rdev->wiphy, chandef,
- IEEE80211_CHAN_DISABLED)) {
+ if (!_cfg80211_chandef_usable(&rdev->wiphy, chandef,
+ IEEE80211_CHAN_DISABLED,
+ monitor)) {
NL_SET_ERR_MSG(extack, "(extension) channel is disabled");
return -EINVAL;
}
@@ -3361,6 +3361,13 @@ int nl80211_parse_chandef(struct cfg80211_registered_device *rdev,
return 0;
}
+int nl80211_parse_chandef(struct cfg80211_registered_device *rdev,
+ struct genl_info *info,
+ struct cfg80211_chan_def *chandef)
+{
+ return _nl80211_parse_chandef(rdev, info, false, chandef);
+}
+
static int __nl80211_set_channel(struct cfg80211_registered_device *rdev,
struct net_device *dev,
struct genl_info *info,
@@ -3385,7 +3392,9 @@ static int __nl80211_set_channel(struct cfg80211_registered_device *rdev,
link_id = 0;
}
- result = nl80211_parse_chandef(rdev, info, &chandef);
+ result = _nl80211_parse_chandef(rdev, info,
+ iftype == NL80211_IFTYPE_MONITOR,
+ &chandef);
if (result)
return result;
--
2.34.1
