[PATCH 2/2] cfg80211: Specify frame and reason code for NL80211_CMD_DEL_STATION

[Jouni Malinen]

The optional NL80211_ATTR_MGMT_SUBTYPE and NL80211_ATTR_REASON_CODE
attributes can now be included in NL80211_CMD_DEL_STATION to indicate to
the driver which frame (Deauthentication/Disassociation) and reason code
in that frame should be used to indicate removal to the specific
station. This is used by drivers that implement AP SME and generate
those frames internally.

Signed-off-by: Jouni Malinen <jouni-A+***@public.gmane.org>
---
include/net/cfg80211.h | 6 ++++++
include/uapi/linux/nl80211.h | 6 +++++-
net/wireless/nl80211.c | 15 +++++++++++++++
net/wireless/trace.h | 10 ++++++++--
4 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 777e191..592e2dc 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -804,9 +804,15 @@ struct station_parameters {
* Used to delete a station entry (or all stations).
*
* @mac: MAC address of the station to remove or NULL to remove all stations
+ * @subtype: Management frame subtype to use for indicating removal
+ * (0 = no guidance on whether to indicate the removal to the station is
+ * provided, 10 = Disassociation, 12 = Deauthentication)
+ * @reason_code: Reason code for the Disassociation/Deauthentication frame
*/
struct station_del_parameters {
const u8 *mac;
+ u8 subtype;
+ u16 reason_code;
};

/**
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 4b28dc0..07ef683 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -227,7 +227,11 @@
* the interface identified by %NL80211_ATTR_IFINDEX.
* @NL80211_CMD_DEL_STATION: Remove a station identified by %NL80211_ATTR_MAC
* or, if no MAC address given, all stations, on the interface identified
- * by %NL80211_ATTR_IFINDEX.
+ * by %NL80211_ATTR_IFINDEX. %NL80211_ATTR_MGMT_SUBTYPE and
+ * %NL80211_ATTR_REASON_CODE can optionally be used to specify which type
+ * of disconnection indication should be sent to the station
+ * (Deauthentication or Disassociation frame and reason code for that
+ * frame).
*
* @NL80211_CMD_GET_MPATH: Get mesh path attributes for mesh path to
* destination %NL80211_ATTR_MAC on the interface identified by
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 9333990..b88b239 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -4414,6 +4414,21 @@ static int nl80211_del_station(struct sk_buff *skb, struct genl_info *info)
if (!rdev->ops->del_station)
return -EOPNOTSUPP;

+ if (info->attrs[NL80211_ATTR_MGMT_SUBTYPE]) {
+ params.subtype =
+ nla_get_u8(info->attrs[NL80211_ATTR_MGMT_SUBTYPE]);
+ if (params.subtype != IEEE80211_STYPE_DISASSOC >> 4 &&
+ params.subtype != IEEE80211_STYPE_DEAUTH >> 4)
+ return -EINVAL;
+ }
+
+ if (info->attrs[NL80211_ATTR_REASON_CODE]) {
+ params.reason_code =
+ nla_get_u16(info->attrs[NL80211_ATTR_REASON_CODE]);
+ if (params.reason_code == 0)
+ return -EINVAL; /* 0 is reserved */
+ }
+
return rdev_del_station(rdev, dev, &params);
}

diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index 66bc3c9..fae55cd 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -688,14 +688,20 @@ DECLARE_EVENT_CLASS(station_del,
WIPHY_ENTRY
NETDEV_ENTRY
MAC_ENTRY(sta_mac)
+ __field(u8, subtype)
+ __field(u16, reason_code)
),
TP_fast_assign(
WIPHY_ASSIGN;
NETDEV_ASSIGN;
MAC_ASSIGN(sta_mac, params->mac);
+ __entry->subtype = params->subtype;
+ __entry->reason_code = params->reason_code;
),
- TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", station mac: " MAC_PR_FMT,
- WIPHY_PR_ARG, NETDEV_PR_ARG, MAC_PR_ARG(sta_mac))
+ TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", station mac: " MAC_PR_FMT
+ ", subtype: %u, reason_code: %u",
+ WIPHY_PR_ARG, NETDEV_PR_ARG, MAC_PR_ARG(sta_mac),
+ __entry->subtype, __entry->reason_code)
);

DEFINE_EVENT(station_del, rdev_del_station,
--
1.9.1

[Johannes Berg]

Post by Jouni Malinen
+ * (0 = no guidance on whether to indicate the removal to the station is
+ * provided, 10 = Disassociation, 12 = Deauthentication)
*/
struct station_del_parameters {
const u8 *mac;
+ u8 subtype;
+ u16 reason_code;

the reason_code could end up being zero right now, if userspace doesn't
specify the attribute.

Post by Jouni Malinen
+ if (info->attrs[NL80211_ATTR_MGMT_SUBTYPE]) {
+ params.subtype =
+ nla_get_u8(info->attrs[NL80211_ATTR_MGMT_SUBTYPE]);
+ if (params.subtype != IEEE80211_STYPE_DISASSOC >> 4 &&
+ params.subtype != IEEE80211_STYPE_DEAUTH >> 4)
+ return -EINVAL;
+ }
+
+ if (info->attrs[NL80211_ATTR_REASON_CODE]) {
+ params.reason_code =
+ nla_get_u16(info->attrs[NL80211_ATTR_REASON_CODE]);
+ if (params.reason_code == 0)
+ return -EINVAL; /* 0 is reserved */
+ }

I think you should probably force a reason code to be given when
specifying the subtype. And I'm thinking that defaulting to deauth/3
would be better than leaving it up to the driver(s)?

johannes

--
To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
the body of a message to majordomo-***@public.gmane.org
More majordomo info at http://vger.kernel.org/majordomo-info.html

[Malinen, Jouni]

Post by Johannes Berg

Post by Jouni Malinen
*/
struct station_del_parameters {
const u8 *mac;
+ u8 subtype;
+ u16 reason_code;

the reason_code could end up being zero right now, if userspace doesn't
specify the attribute.

That was more or less by design, but not really fully documented and not
really supposed to be used if the subtype is not provided.

Post by Johannes Berg
I think you should probably force a reason code to be given when
specifying the subtype. And I'm thinking that defaulting to deauth/3
would be better than leaving it up to the driver(s)?

I guess we could do that in cfg80211. I was trying to follow the current
behavior for this (i.e., not telling the driver what to do if user space
does not require something). As an example, ath6kl uses Deauthentication
with reason code 2. I don't think reason code 3 would be a good default,
though, since it has a special meaning for P2P groups (GO indicates group
is being terminated). That specific use case is one of the main reasons
for making sure that user space can specify that Deauthentication with a
specific reason code is used.

I think I would be fine with cfg80211 default being Deauthentication frame
with reason code 2, so if that is what you would like to see here (rather
than leaving this to the drivers), I can update the patch to behave in
that way.

- Jouni

--
To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
the body of a message to majordomo-***@public.gmane.org
More majordomo info at http://vger.kernel.org/majordomo-info.html

[Johannes Berg]

Post by Malinen, Jouni
I think I would be fine with cfg80211 default being Deauthentication frame
with reason code 2, so if that is what you would like to see here (rather
than leaving this to the drivers), I can update the patch to behave in
that way.

As discussed in Duesseldorf, please do so.

johannes

--
To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
the body of a message to majordomo-***@public.gmane.org
More majordomo info at http://vger.kernel.org/majordomo-info.html

[Jouni Malinen]

The optional NL80211_ATTR_MGMT_SUBTYPE and NL80211_ATTR_REASON_CODE
attributes can now be included in NL80211_CMD_DEL_STATION to indicate to
the driver which frame (Deauthentication/Disassociation) and reason code
in that frame should be used to indicate removal to the specific
station. This is used by drivers that implement AP SME and generate
those frames internally.

Signed-off-by: Jouni Malinen <jouni-A+***@public.gmane.org>
---
include/net/cfg80211.h | 5 +++++
include/uapi/linux/nl80211.h | 6 +++++-
net/wireless/nl80211.c | 21 +++++++++++++++++++++
net/wireless/trace.h | 10 ++++++++--
4 files changed, 39 insertions(+), 3 deletions(-)

v2: Move default behavior selection to cfg80211 so that drivers will
always get an indication of subtype and reason_code.


diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 777e191..23308fb 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -804,9 +804,14 @@ struct station_parameters {
* Used to delete a station entry (or all stations).
*
* @mac: MAC address of the station to remove or NULL to remove all stations
+ * @subtype: Management frame subtype to use for indicating removal
+ * (10 = Disassociation, 12 = Deauthentication)
+ * @reason_code: Reason code for the Disassociation/Deauthentication frame
*/
struct station_del_parameters {
const u8 *mac;
+ u8 subtype;
+ u16 reason_code;
};

/**
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 4b28dc0..07ef683 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -227,7 +227,11 @@
* the interface identified by %NL80211_ATTR_IFINDEX.
* @NL80211_CMD_DEL_STATION: Remove a station identified by %NL80211_ATTR_MAC
* or, if no MAC address given, all stations, on the interface identified
- * by %NL80211_ATTR_IFINDEX.
+ * by %NL80211_ATTR_IFINDEX. %NL80211_ATTR_MGMT_SUBTYPE and
+ * %NL80211_ATTR_REASON_CODE can optionally be used to specify which type
+ * of disconnection indication should be sent to the station
+ * (Deauthentication or Disassociation frame and reason code for that
+ * frame).
*
* @NL80211_CMD_GET_MPATH: Get mesh path attributes for mesh path to
* destination %NL80211_ATTR_MAC on the interface identified by
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 9333990..f6902ce 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -4414,6 +4414,27 @@ static int nl80211_del_station(struct sk_buff *skb, struct genl_info *info)
if (!rdev->ops->del_station)
return -EOPNOTSUPP;

+ if (info->attrs[NL80211_ATTR_MGMT_SUBTYPE]) {
+ params.subtype =
+ nla_get_u8(info->attrs[NL80211_ATTR_MGMT_SUBTYPE]);
+ if (params.subtype != IEEE80211_STYPE_DISASSOC >> 4 &&
+ params.subtype != IEEE80211_STYPE_DEAUTH >> 4)
+ return -EINVAL;
+ } else {
+ /* Default to Deauthentication frame */
+ params.subtype = IEEE80211_STYPE_DEAUTH >> 4;
+ }
+
+ if (info->attrs[NL80211_ATTR_REASON_CODE]) {
+ params.reason_code =
+ nla_get_u16(info->attrs[NL80211_ATTR_REASON_CODE]);
+ if (params.reason_code == 0)
+ return -EINVAL; /* 0 is reserved */
+ } else {
+ /* Default to reason code 2 */
+ params.reason_code = WLAN_REASON_PREV_AUTH_NOT_VALID;
+ }
+
return rdev_del_station(rdev, dev, &params);
}

diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index 66bc3c9..fae55cd 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -688,14 +688,20 @@ DECLARE_EVENT_CLASS(station_del,
WIPHY_ENTRY
NETDEV_ENTRY
MAC_ENTRY(sta_mac)
+ __field(u8, subtype)
+ __field(u16, reason_code)
),
TP_fast_assign(
WIPHY_ASSIGN;
NETDEV_ASSIGN;
MAC_ASSIGN(sta_mac, params->mac);
+ __entry->subtype = params->subtype;
+ __entry->reason_code = params->reason_code;
),
- TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", station mac: " MAC_PR_FMT,
- WIPHY_PR_ARG, NETDEV_PR_ARG, MAC_PR_ARG(sta_mac))
+ TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", station mac: " MAC_PR_FMT
+ ", subtype: %u, reason_code: %u",
+ WIPHY_PR_ARG, NETDEV_PR_ARG, MAC_PR_ARG(sta_mac),
+ __entry->subtype, __entry->reason_code)
);

DEFINE_EVENT(station_del, rdev_del_station,

[Johannes Berg]

Post by Jouni Malinen
The optional NL80211_ATTR_MGMT_SUBTYPE and NL80211_ATTR_REASON_CODE
attributes can now be included in NL80211_CMD_DEL_STATION to indicate to
the driver which frame (Deauthentication/Disassociation) and reason code
in that frame should be used to indicate removal to the specific
station. This is used by drivers that implement AP SME and generate
those frames internally.

Applied.

johannes

--
To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
the body of a message to majordomo-***@public.gmane.org
More majordomo info at http://vger.kernel.org/majordomo-info.html