[RFC PATCH v1] cfg80211/nl80211: add support for AID assignment by driver

[RFC PATCH v1] cfg80211/nl80211: add support for AID assignment by driver

[Sarada Prasanna Garnayak]

Add support for getting and free association ID if the station
association ID management handled by the WLAN driver/firmware.

Add cfg80211 driver ops and nl80211 API and CMD to request
the WLAN driver to assign an AID for a station during association
and release the AID of the station from the WLAN driver/firmware
station database on disassociation from the AP.

Signed-off-by: Sarada Prasanna Garnayak <sarada.prasanna.garnayak@intel.com>
---
 include/net/cfg80211.h       | 12 +++++++
 include/uapi/linux/nl80211.h | 11 +++++++
 net/wireless/nl80211.c       | 74 ++++++++++++++++++++++++++++++++++++++++++++
 net/wireless/rdev-ops.h      | 22 +++++++++++++
 net/wireless/trace.h         | 36 +++++++++++++++++++++
 5 files changed, 155 insertions(+)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 1fa41b7a1be3..b80080a32e4a 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -3183,6 +3183,13 @@ struct cfg80211_ftm_responder_stats {
  *
  * @get_ftm_responder_stats: Retrieve FTM responder statistics, if available.
  *	Statistics should be cumulative, currently no way to reset is provided.
+ *
+ * @get_sta_aid: Get an AID for the station from the driver if AID assignment
+ *	is managed by the WLAN driver/hardware/firmware.
+ *
+ * @free_sta_aid: Release the AID of the station from the station database
+ *	on disassociation from the AP if AID assignment is managed by
+ *	the WLAN driver/hardware/firmware.
  */
 struct cfg80211_ops {
 	int	(*suspend)(struct wiphy *wiphy, struct cfg80211_wowlan *wow);
@@ -3492,6 +3499,11 @@ struct cfg80211_ops {
 	int	(*get_ftm_responder_stats)(struct wiphy *wiphy,
 				struct net_device *dev,
 				struct cfg80211_ftm_responder_stats *ftm_stats);
+
+	int (*get_sta_aid)(struct wiphy *wiphy, struct net_device *dev,
+			   u16 *sta_aid, const u8 *mac_addr);
+	int (*free_sta_aid)(struct wiphy *wiphy, struct net_device *dev,
+			    u16 sta_aid);
 };
 
 /*
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 6d610bae30a9..ea194ccc7888 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -1036,6 +1036,14 @@
  * @NL80211_CMD_GET_FTM_RESPONDER_STATS: Retrieve FTM responder statistics, in
  *	the %NL80211_ATTR_FTM_RESPONDER_STATS attribute.
  *
+ * @NL80211_CMD_GET_STA_AID: Request association ID for a station if the station
+ *	association ID management handled by the driver/firmware/hardware
+ *	specified by %NL80211_ATTR_MAC and %NL80211_ATTR_STA_AID.
+ *
+ * @NL80211_CMD_FREE_STA_AID: Free association ID of a station if the station
+ *	association ID management handled by the driver/firmware/hardware
+ *	with specified by %NL80211_ATTR_STA_AID.
+ *
  * @NL80211_CMD_MAX: highest used command number
  * @__NL80211_CMD_AFTER_LAST: internal use
  */
@@ -1250,6 +1258,9 @@ enum nl80211_commands {
 
 	NL80211_CMD_GET_FTM_RESPONDER_STATS,
 
+	NL80211_CMD_GET_STA_AID,
+	NL80211_CMD_FREE_STA_AID,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 8d763725498c..662309d2c577 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -3391,6 +3391,66 @@ static void get_key_callback(void *c, struct key_params *params)
 	cookie->error = 1;
 }
 
+static int nl80211_get_sta_aid(struct sk_buff *skb, struct genl_info *info)
+{
+	struct cfg80211_registered_device *rdev = info->user_ptr[0];
+	int err;
+	struct net_device *dev = info->user_ptr[1];
+	const u8 *mac_addr = NULL;
+	u16 *sta_aid = NULL;
+	void *hdr;
+	struct sk_buff *msg;
+
+	if (info->attrs[NL80211_ATTR_STA_AID])
+		sta_aid = nla_data(info->attrs[NL80211_ATTR_STA_AID]);
+
+	if (info->attrs[NL80211_ATTR_MAC])
+		mac_addr = nla_data(info->attrs[NL80211_ATTR_MAC]);
+
+	if (!rdev->ops->get_sta_aid)
+		return -EOPNOTSUPP;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	hdr = nl80211hdr_put(msg, info->snd_portid, info->snd_seq, 0,
+			     NL80211_CMD_GET_STA_AID);
+	if (!hdr)
+		goto get_sta_aid_err;
+
+	err = rdev_get_sta_aid(rdev, dev, sta_aid, mac_addr);
+	if (err)
+		goto get_sta_aid_err;
+
+	if (nla_put(msg, NL80211_ATTR_STA_AID, sizeof(*sta_aid), sta_aid) ||
+	    nla_put(msg, NL80211_ATTR_MAC, ETH_ALEN, mac_addr))
+		goto get_sta_aid_err;
+
+	genlmsg_end(msg, hdr);
+	return genlmsg_reply(msg, info);
+
+get_sta_aid_err:
+	err = -ENOBUFS;
+	nlmsg_free(msg);
+	return err;
+}
+
+static int nl80211_free_sta_aid(struct sk_buff *skb, struct genl_info *info)
+{
+	struct cfg80211_registered_device *rdev = info->user_ptr[0];
+	struct net_device *dev = info->user_ptr[1];
+	u16 sta_aid = 0;
+
+	if (info->attrs[NL80211_ATTR_STA_AID])
+		sta_aid = nla_get_u16(info->attrs[NL80211_ATTR_STA_AID]);
+
+	if (!rdev->ops->free_sta_aid)
+		return -EOPNOTSUPP;
+
+	return rdev_free_sta_aid(rdev, dev, sta_aid);
+}
+
 static int nl80211_get_key(struct sk_buff *skb, struct genl_info *info)
 {
 	struct cfg80211_registered_device *rdev = info->user_ptr[0];
@@ -13899,6 +13959,20 @@ static const struct genl_ops nl80211_ops[] = {
 		.internal_flags = NL80211_FLAG_NEED_NETDEV |
 				  NL80211_FLAG_NEED_RTNL,
 	},
+	{
+		.cmd = NL80211_CMD_GET_STA_AID,
+		.doit = nl80211_get_sta_aid,
+		.policy = nl80211_policy,
+		.internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+				  NL80211_FLAG_NEED_RTNL,
+	},
+	{
+		.cmd = NL80211_CMD_FREE_STA_AID,
+		.doit = nl80211_free_sta_aid,
+		.policy = nl80211_policy,
+		.internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+				  NL80211_FLAG_NEED_RTNL,
+	},
 };
 
 static struct genl_family nl80211_fam __ro_after_init = {
diff --git a/net/wireless/rdev-ops.h b/net/wireless/rdev-ops.h
index 51380b5c32f2..44e9cc489ec3 100644
--- a/net/wireless/rdev-ops.h
+++ b/net/wireless/rdev-ops.h
@@ -71,6 +71,28 @@ rdev_change_virtual_intf(struct cfg80211_registered_device *rdev,
 	return ret;
 }
 
+static inline int
+rdev_get_sta_aid(struct cfg80211_registered_device *rdev,
+		 struct net_device *netdev, u16 *sta_aid, const u8 *mac_addr)
+{
+	int ret;
+	trace_rdev_get_sta_aid(&rdev->wiphy, netdev, sta_aid, mac_addr);
+	ret = rdev->ops->get_sta_aid(&rdev->wiphy, netdev, sta_aid, mac_addr);
+	trace_rdev_return_int(&rdev->wiphy, ret);
+	return ret;
+}
+
+static inline int
+rdev_free_sta_aid(struct cfg80211_registered_device *rdev,
+		  struct net_device *netdev, u16 sta_aid)
+{
+	int ret;
+	trace_rdev_free_sta_aid(&rdev->wiphy, netdev, sta_aid);
+	ret = rdev->ops->free_sta_aid(&rdev->wiphy, netdev, sta_aid);
+	trace_rdev_return_int(&rdev->wiphy, ret);
+	return ret;
+}
+
 static inline int rdev_add_key(struct cfg80211_registered_device *rdev,
 			       struct net_device *netdev, u8 key_index,
 			       bool pairwise, const u8 *mac_addr,
diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index c6a9446b4e6b..646bd937ebea 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -389,6 +389,42 @@ TRACE_EVENT(rdev_change_virtual_intf,
 		  WIPHY_PR_ARG, NETDEV_PR_ARG, __entry->type)
 );
 
+TRACE_EVENT(rdev_get_sta_aid,
+	TP_PROTO(struct wiphy *wiphy, struct net_device *netdev,
+		 u16 *sta_aid, const u8 *mac_addr),
+	TP_ARGS(wiphy, netdev, sta_aid, mac_addr),
+	TP_STRUCT__entry(
+		WIPHY_ENTRY
+		NETDEV_ENTRY
+		MAC_ENTRY(mac_addr)
+	),
+	TP_fast_assign(
+	WIPHY_ASSIGN;
+	NETDEV_ASSIGN;
+	MAC_ASSIGN(mac_addr, mac_addr);
+	),
+	TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", mac addr: " MAC_PR_FMT,
+		WIPHY_PR_ARG, NETDEV_PR_ARG, MAC_PR_ARG(mac_addr))
+);
+
+TRACE_EVENT(rdev_free_sta_aid,
+	TP_PROTO(struct wiphy *wiphy, struct net_device *netdev,
+		 u16 sta_aid),
+	TP_ARGS(wiphy, netdev, sta_aid),
+	TP_STRUCT__entry(
+	WIPHY_ENTRY
+	NETDEV_ENTRY
+	__field(u16, sta_aid)
+	),
+	TP_fast_assign(
+	WIPHY_ASSIGN;
+	NETDEV_ASSIGN;
+	__entry->sta_aid = sta_aid;
+	),
+	TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", station aid : %hu",
+		WIPHY_PR_ARG, NETDEV_PR_ARG, __entry->sta_aid)
+);
+
 DECLARE_EVENT_CLASS(key_handle,
 	TP_PROTO(struct wiphy *wiphy, struct net_device *netdev, u8 key_index,
 		 bool pairwise, const u8 *mac_addr),
-- 
2.11.0

Re: [RFC PATCH v1] cfg80211/nl80211: add support for AID assignment by driver

[Sergey Matyukevich]

Hi,

> Add support for getting and free association ID if the station
> association ID management handled by the WLAN driver/firmware.
> 
> Add cfg80211 driver ops and nl80211 API and CMD to request
> the WLAN driver to assign an AID for a station during association
> and release the AID of the station from the WLAN driver/firmware
> station database on disassociation from the AP.
> 
> Signed-off-by: Sarada Prasanna Garnayak <sarada.prasanna.garnayak@intel.com>
> ---
>  include/net/cfg80211.h       | 12 +++++++
>  include/uapi/linux/nl80211.h | 11 +++++++
>  net/wireless/nl80211.c       | 74 ++++++++++++++++++++++++++++++++++++++++++++
>  net/wireless/rdev-ops.h      | 22 +++++++++++++
>  net/wireless/trace.h         | 36 +++++++++++++++++++++
>  5 files changed, 155 insertions(+)

Could you please clarify the use-cases for this feature and its potential
users ? Besides, why existing nl80211_set_station can't be used ? It turns
out that there exists station AID field among numerous
'struct station_parameters' fields.

Regards,
Sergey

[RFC PATCH v1] cfg80211/nl80211: add support for AID assignment by driver

[Sarada Prasanna Garnayak]

Add support for getting and free association ID if the station
association ID management handled by the WLAN driver/firmware.

Add cfg80211 driver ops and nl80211 API and CMD to request
the WLAN driver to assign an AID for a station during association
and release the AID of the station from the WLAN driver/firmware
station database on disassociation from the AP.

Signed-off-by: Sarada Prasanna Garnayak <sarada.prasanna.garnayak@intel.com>
---
 include/net/cfg80211.h       | 11 +++++++
 include/uapi/linux/nl80211.h | 11 +++++++
 net/wireless/nl80211.c       | 74 ++++++++++++++++++++++++++++++++++++++++++++
 net/wireless/rdev-ops.h      | 22 +++++++++++++
 net/wireless/trace.h         | 36 +++++++++++++++++++++
 5 files changed, 154 insertions(+)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 1fa41b7a1be3..27d7c6605055 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -3183,6 +3183,12 @@ struct cfg80211_ftm_responder_stats {
  *
  * @get_ftm_responder_stats: Retrieve FTM responder statistics, if available.
  *	Statistics should be cumulative, currently no way to reset is provided.
+ * @get_sta_aid: Get an AID for the station from the driver if AID assignment
+ *	is managed by the WLAN driver/hardware/firmware.
+ *
+ * @free_sta_aid: Release the AID of the station from the station database
+ *	on disassociation from the AP if AID assignment is managed by
+ *	the WLAN driver/hardware/firmware.
  */
 struct cfg80211_ops {
 	int	(*suspend)(struct wiphy *wiphy, struct cfg80211_wowlan *wow);
@@ -3492,6 +3498,11 @@ struct cfg80211_ops {
 	int	(*get_ftm_responder_stats)(struct wiphy *wiphy,
 				struct net_device *dev,
 				struct cfg80211_ftm_responder_stats *ftm_stats);
+
+	int (*get_sta_aid)(struct wiphy *wiphy, struct net_device *dev,
+			   u16 *sta_aid, const u8 *mac_addr);
+	int (*free_sta_aid)(struct wiphy *wiphy, struct net_device *dev,
+			    u16 sta_aid);
 };
 
 /*
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 6d610bae30a9..ea194ccc7888 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -1036,6 +1036,14 @@
  * @NL80211_CMD_GET_FTM_RESPONDER_STATS: Retrieve FTM responder statistics, in
  *	the %NL80211_ATTR_FTM_RESPONDER_STATS attribute.
  *
+ * @NL80211_CMD_GET_STA_AID: Request association ID for a station if the station
+ *	association ID management handled by the driver/firmware/hardware
+ *	specified by %NL80211_ATTR_MAC and %NL80211_ATTR_STA_AID.
+ *
+ * @NL80211_CMD_FREE_STA_AID: Free association ID of a station if the station
+ *	association ID management handled by the driver/firmware/hardware
+ *	with specified by %NL80211_ATTR_STA_AID.
+ *
  * @NL80211_CMD_MAX: highest used command number
  * @__NL80211_CMD_AFTER_LAST: internal use
  */
@@ -1250,6 +1258,9 @@ enum nl80211_commands {
 
 	NL80211_CMD_GET_FTM_RESPONDER_STATS,
 
+	NL80211_CMD_GET_STA_AID,
+	NL80211_CMD_FREE_STA_AID,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 8d763725498c..662309d2c577 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -3391,6 +3391,66 @@ static void get_key_callback(void *c, struct key_params *params)
 	cookie->error = 1;
 }
 
+static int nl80211_get_sta_aid(struct sk_buff *skb, struct genl_info *info)
+{
+	struct cfg80211_registered_device *rdev = info->user_ptr[0];
+	int err;
+	struct net_device *dev = info->user_ptr[1];
+	const u8 *mac_addr = NULL;
+	u16 *sta_aid = NULL;
+	void *hdr;
+	struct sk_buff *msg;
+
+	if (info->attrs[NL80211_ATTR_STA_AID])
+		sta_aid = nla_data(info->attrs[NL80211_ATTR_STA_AID]);
+
+	if (info->attrs[NL80211_ATTR_MAC])
+		mac_addr = nla_data(info->attrs[NL80211_ATTR_MAC]);
+
+	if (!rdev->ops->get_sta_aid)
+		return -EOPNOTSUPP;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	hdr = nl80211hdr_put(msg, info->snd_portid, info->snd_seq, 0,
+			     NL80211_CMD_GET_STA_AID);
+	if (!hdr)
+		goto get_sta_aid_err;
+
+	err = rdev_get_sta_aid(rdev, dev, sta_aid, mac_addr);
+	if (err)
+		goto get_sta_aid_err;
+
+	if (nla_put(msg, NL80211_ATTR_STA_AID, sizeof(*sta_aid), sta_aid) ||
+	    nla_put(msg, NL80211_ATTR_MAC, ETH_ALEN, mac_addr))
+		goto get_sta_aid_err;
+
+	genlmsg_end(msg, hdr);
+	return genlmsg_reply(msg, info);
+
+get_sta_aid_err:
+	err = -ENOBUFS;
+	nlmsg_free(msg);
+	return err;
+}
+
+static int nl80211_free_sta_aid(struct sk_buff *skb, struct genl_info *info)
+{
+	struct cfg80211_registered_device *rdev = info->user_ptr[0];
+	struct net_device *dev = info->user_ptr[1];
+	u16 sta_aid = 0;
+
+	if (info->attrs[NL80211_ATTR_STA_AID])
+		sta_aid = nla_get_u16(info->attrs[NL80211_ATTR_STA_AID]);
+
+	if (!rdev->ops->free_sta_aid)
+		return -EOPNOTSUPP;
+
+	return rdev_free_sta_aid(rdev, dev, sta_aid);
+}
+
 static int nl80211_get_key(struct sk_buff *skb, struct genl_info *info)
 {
 	struct cfg80211_registered_device *rdev = info->user_ptr[0];
@@ -13899,6 +13959,20 @@ static const struct genl_ops nl80211_ops[] = {
 		.internal_flags = NL80211_FLAG_NEED_NETDEV |
 				  NL80211_FLAG_NEED_RTNL,
 	},
+	{
+		.cmd = NL80211_CMD_GET_STA_AID,
+		.doit = nl80211_get_sta_aid,
+		.policy = nl80211_policy,
+		.internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+				  NL80211_FLAG_NEED_RTNL,
+	},
+	{
+		.cmd = NL80211_CMD_FREE_STA_AID,
+		.doit = nl80211_free_sta_aid,
+		.policy = nl80211_policy,
+		.internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+				  NL80211_FLAG_NEED_RTNL,
+	},
 };
 
 static struct genl_family nl80211_fam __ro_after_init = {
diff --git a/net/wireless/rdev-ops.h b/net/wireless/rdev-ops.h
index 51380b5c32f2..44e9cc489ec3 100644
--- a/net/wireless/rdev-ops.h
+++ b/net/wireless/rdev-ops.h
@@ -71,6 +71,28 @@ rdev_change_virtual_intf(struct cfg80211_registered_device *rdev,
 	return ret;
 }
 
+static inline int
+rdev_get_sta_aid(struct cfg80211_registered_device *rdev,
+		 struct net_device *netdev, u16 *sta_aid, const u8 *mac_addr)
+{
+	int ret;
+	trace_rdev_get_sta_aid(&rdev->wiphy, netdev, sta_aid, mac_addr);
+	ret = rdev->ops->get_sta_aid(&rdev->wiphy, netdev, sta_aid, mac_addr);
+	trace_rdev_return_int(&rdev->wiphy, ret);
+	return ret;
+}
+
+static inline int
+rdev_free_sta_aid(struct cfg80211_registered_device *rdev,
+		  struct net_device *netdev, u16 sta_aid)
+{
+	int ret;
+	trace_rdev_free_sta_aid(&rdev->wiphy, netdev, sta_aid);
+	ret = rdev->ops->free_sta_aid(&rdev->wiphy, netdev, sta_aid);
+	trace_rdev_return_int(&rdev->wiphy, ret);
+	return ret;
+}
+
 static inline int rdev_add_key(struct cfg80211_registered_device *rdev,
 			       struct net_device *netdev, u8 key_index,
 			       bool pairwise, const u8 *mac_addr,
diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index c6a9446b4e6b..646bd937ebea 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -389,6 +389,42 @@ TRACE_EVENT(rdev_change_virtual_intf,
 		  WIPHY_PR_ARG, NETDEV_PR_ARG, __entry->type)
 );
 
+TRACE_EVENT(rdev_get_sta_aid,
+	TP_PROTO(struct wiphy *wiphy, struct net_device *netdev,
+		 u16 *sta_aid, const u8 *mac_addr),
+	TP_ARGS(wiphy, netdev, sta_aid, mac_addr),
+	TP_STRUCT__entry(
+		WIPHY_ENTRY
+		NETDEV_ENTRY
+		MAC_ENTRY(mac_addr)
+	),
+	TP_fast_assign(
+	WIPHY_ASSIGN;
+	NETDEV_ASSIGN;
+	MAC_ASSIGN(mac_addr, mac_addr);
+	),
+	TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", mac addr: " MAC_PR_FMT,
+		WIPHY_PR_ARG, NETDEV_PR_ARG, MAC_PR_ARG(mac_addr))
+);
+
+TRACE_EVENT(rdev_free_sta_aid,
+	TP_PROTO(struct wiphy *wiphy, struct net_device *netdev,
+		 u16 sta_aid),
+	TP_ARGS(wiphy, netdev, sta_aid),
+	TP_STRUCT__entry(
+	WIPHY_ENTRY
+	NETDEV_ENTRY
+	__field(u16, sta_aid)
+	),
+	TP_fast_assign(
+	WIPHY_ASSIGN;
+	NETDEV_ASSIGN;
+	__entry->sta_aid = sta_aid;
+	),
+	TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", station aid : %hu",
+		WIPHY_PR_ARG, NETDEV_PR_ARG, __entry->sta_aid)
+);
+
 DECLARE_EVENT_CLASS(key_handle,
 	TP_PROTO(struct wiphy *wiphy, struct net_device *netdev, u8 key_index,
 		 bool pairwise, const u8 *mac_addr),
-- 
2.11.0

Re: [RFC PATCH v1] cfg80211/nl80211: add support for AID assignment by driver

[Kalle Valo]

Sarada Prasanna Garnayak <sarada.prasanna.garnayak@intel.com> writes:

> Add support for getting and free association ID if the station
> association ID management handled by the WLAN driver/firmware.
>
> Add cfg80211 driver ops and nl80211 API and CMD to request
> the WLAN driver to assign an AID for a station during association
> and release the AID of the station from the WLAN driver/firmware
> station database on disassociation from the AP.
>
> Signed-off-by: Sarada Prasanna Garnayak <sarada.prasanna.garnayak@intel.com>

[...]

> --- a/include/net/cfg80211.h
> +++ b/include/net/cfg80211.h
> @@ -3183,6 +3183,12 @@ struct cfg80211_ftm_responder_stats {
>   *
>   * @get_ftm_responder_stats: Retrieve FTM responder statistics, if available.
>   *	Statistics should be cumulative, currently no way to reset is provided.
> + * @get_sta_aid: Get an AID for the station from the driver if AID assignment
> + *	is managed by the WLAN driver/hardware/firmware.
> + *
> + * @free_sta_aid: Release the AID of the station from the station database
> + *	on disassociation from the AP if AID assignment is managed by
> + *	the WLAN driver/hardware/firmware.
>   */
>  struct cfg80211_ops {
>  	int	(*suspend)(struct wiphy *wiphy, struct cfg80211_wowlan *wow);
> @@ -3492,6 +3498,11 @@ struct cfg80211_ops {
>  	int	(*get_ftm_responder_stats)(struct wiphy *wiphy,
>  				struct net_device *dev,
>  				struct cfg80211_ftm_responder_stats *ftm_stats);
> +
> +	int (*get_sta_aid)(struct wiphy *wiphy, struct net_device *dev,
> +			   u16 *sta_aid, const u8 *mac_addr);

If I'm reading this patch correctly it looks like sta_aid or mac_addr
(or even both?) can be NULL? How should the driver handle that? I didn't
see any mentions of this in the document.

-- 
Kalle Valo

Re: [RFC PATCH v1] cfg80211/nl80211: add support for AID assignment by driver

[Johannes Berg]

Hi,

On Wed, 2018-12-12 at 23:39 +0530, Sarada Prasanna Garnayak wrote:
> Add support for getting and free association ID if the station
> association ID management handled by the WLAN driver/firmware.
> 
> Add cfg80211 driver ops and nl80211 API and CMD to request
> the WLAN driver to assign an AID for a station during association
> and release the AID of the station from the WLAN driver/firmware
> station database on disassociation from the AP.

I think this should state why it's needed - i.e. why the implied "use
lowest possible AID" assignment scheme isn't sufficient for some/your
driver(s). That scheme has advantages in the TIM Element for example, so
deviating from it might cause other issues.

> + * @get_sta_aid: Get an AID for the station from the driver if AID assignment
> + *	is managed by the WLAN driver/hardware/firmware.

This seems reasonable, but let me think about it more below.

> + * @free_sta_aid: Release the AID of the station from the station database
> + *	on disassociation from the AP if AID assignment is managed by
> + *	the WLAN driver/hardware/firmware.

I'm not convinced this makes sense. The station entry will be freed by
hostapd anyway, and in that case the AID is freed implicitly. I see no
reason to split these operations.

In fact, I'm not sure we need an allocation operation either, since we
should be able to assign one when the station entry is added.

> +	int (*get_sta_aid)(struct wiphy *wiphy, struct net_device *dev,
> +			   u16 *sta_aid, const u8 *mac_addr);

If we do this, we should probably *return* the AID, that doesn't overlap
with error return values since AIDs are positive and error codes
negative.

> + * @NL80211_CMD_GET_STA_AID: Request association ID for a station if the station
> + *	association ID management handled by the driver/firmware/hardware
> + *	specified by %NL80211_ATTR_MAC and %NL80211_ATTR_STA_AID.
> + *
> + * @NL80211_CMD_FREE_STA_AID: Free association ID of a station if the station
> + *	association ID management handled by the driver/firmware/hardware
> + *	with specified by %NL80211_ATTR_STA_AID.

Same comments as above of course apply to the nl80211 API.

However, in any case, I don't really see why we need this at all.

Normally, the flow (nowadays) is to add a station when it authenticates,
and so at that point the AID could be assigned by the driver in the
station entry. We need to think about the capabilities for this, and how
to force hostapd to actually do this flow (or have the driver accept
AIDs from hostapd if it's an old version?)

johannes