cfg80211: add WMM traffic stream API

Add nl80211 and driver API to validate, add and delete traffic
streams with appropriate settings.

The API calls for userspace doing the action frame handshake
with the peer, and then allows only to set up the parameters
in the driver. To avoid setting up a session only to tear it
down again, the validate API is provided, but the real usage
later can still fail so userspace must be prepared for that.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/linux/ieee80211.h

@@ -166,8 +166,12 @@ static inline u16 ieee80211_sn_sub(u16 sn1, u16 sn2)
 
 #define IEEE80211_MAX_MESH_ID_LEN	32
 
+#define IEEE80211_FIRST_TSPEC_TSID	8
 #define IEEE80211_NUM_TIDS		16
 
+/* number of user priorities 802.11 uses */
+#define IEEE80211_NUM_UPS		8
+
 #define IEEE80211_QOS_CTL_LEN		2
 /* 1d tag mask */
 #define IEEE80211_QOS_CTL_TAG1D_MASK		0x0007

include/net/cfg80211.h

@@ -2318,6 +2318,17 @@ struct cfg80211_qos_map {
  * @set_ap_chanwidth: Set the AP (including P2P GO) mode channel width for the
  *	given interface This is used e.g. for dynamic HT 20/40 MHz channel width
  *	changes during the lifetime of the BSS.
+ *
+ * @add_tx_ts: validate (if admitted_time is 0) or add a TX TS to the device
+ *	with the given parameters; action frame exchange has been handled by
+ *	userspace so this just has to modify the TX path to take the TS into
+ *	account.
+ *	If the admitted time is 0 just validate the parameters to make sure
+ *	the session can be created at all; it is valid to just always return
+ *	success for that but that may result in inefficient behaviour (handshake
+ *	with the peer followed by immediate teardown when the addition is later
+ *	rejected)
+ * @del_tx_ts: remove an existing TX TS
  */
 struct cfg80211_ops {
 	int	(*suspend)(struct wiphy *wiphy, struct cfg80211_wowlan *wow);
@@ -2558,6 +2569,12 @@ struct cfg80211_ops {
 
 	int	(*set_ap_chanwidth)(struct wiphy *wiphy, struct net_device *dev,
 				    struct cfg80211_chan_def *chandef);
+
+	int	(*add_tx_ts)(struct wiphy *wiphy, struct net_device *dev,
+			     u8 tsid, const u8 *peer, u8 user_prio,
+			     u16 admitted_time);
+	int	(*del_tx_ts)(struct wiphy *wiphy, struct net_device *dev,
+			     u8 tsid, const u8 *peer);
 };
 
 /*
@@ -2604,9 +2621,13 @@ struct cfg80211_ops {
  * @WIPHY_FLAG_SUPPORTS_5_10_MHZ: Device supports 5 MHz and 10 MHz channels.
  * @WIPHY_FLAG_HAS_CHANNEL_SWITCH: Device supports channel switch in
  *	beaconing mode (AP, IBSS, Mesh, ...).
+ * @WIPHY_FLAG_SUPPORTS_WMM_ADMISSION: the device supports setting up WMM
+ *	TSPEC sessions (TID aka TSID 0-7) with the NL80211_CMD_ADD_TX_TS
+ *	command. Standard IEEE 802.11 TSPEC setup is not yet supported, it
+ *	needs to be able to handle Block-Ack agreements and other things.
  */
 enum wiphy_flags {
-	/* use hole at 0 */
+	WIPHY_FLAG_SUPPORTS_WMM_ADMISSION	= BIT(0),
 	/* use hole at 1 */
 	/* use hole at 2 */
 	WIPHY_FLAG_NETNS_OK			= BIT(3),

include/uapi/linux/nl80211.h

@@ -722,6 +722,22 @@
  *	QoS mapping is relevant for IP packets, it is only valid during an
  *	association. This is cleared on disassociation and AP restart.
  *
+ * @NL80211_CMD_ADD_TX_TS: Ask the kernel to add a traffic stream for the given
+ *	%NL80211_ATTR_TSID and %NL80211_ATTR_MAC with %NL80211_ATTR_USER_PRIO
+ *	and %NL80211_ATTR_ADMITTED_TIME parameters.
+ *	Note that the action frame handshake with the AP shall be handled by
+ *	userspace via the normal management RX/TX framework, this only sets
+ *	up the TX TS in the driver/device.
+ *	If the admitted time attribute is not added then the request just checks
+ *	if a subsequent setup could be successful, the intent is to use this to
+ *	avoid setting up a session with the AP when local restrictions would
+ *	make that impossible. However, the subsequent "real" setup may still
+ *	fail even if the check was successful.
+ * @NL80211_CMD_DEL_TX_TS: Remove an existing TS with the %NL80211_ATTR_TSID
+ *	and %NL80211_ATTR_MAC parameters. It isn't necessary to call this
+ *	before removing a station entry entirely, or before disassociating
+ *	or similar, cleanup will happen in the driver/device in this case.
+ *
  * @NL80211_CMD_MAX: highest used command number
  * @__NL80211_CMD_AFTER_LAST: internal use
  */
@@ -893,6 +909,9 @@ enum nl80211_commands {
 
 	NL80211_CMD_SET_QOS_MAP,
 
+	NL80211_CMD_ADD_TX_TS,
+	NL80211_CMD_DEL_TX_TS,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */
@@ -1611,6 +1630,11 @@ enum nl80211_commands {
  *	drivers to indicate dynack capability. Dynack is automatically disabled
  *	setting valid value for coverage class.
  *
+ * @NL80211_ATTR_TSID: a TSID value (u8 attribute)
+ * @NL80211_ATTR_USER_PRIO: user priority value (u8 attribute)
+ * @NL80211_ATTR_ADMITTED_TIME: admitted time in units of 32 microseconds
+ *	(per second) (u16 attribute)
+ *
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
  */
@@ -1957,6 +1981,10 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_WIPHY_DYN_ACK,
 
+	NL80211_ATTR_TSID,
+	NL80211_ATTR_USER_PRIO,
+	NL80211_ATTR_ADMITTED_TIME,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,

net/wireless/nl80211.c

@@ -391,6 +391,9 @@ static const struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] = {
 	[NL80211_ATTR_IFACE_SOCKET_OWNER] = { .type = NLA_FLAG },
 	[NL80211_ATTR_CSA_C_OFFSETS_TX] = { .type = NLA_BINARY },
 	[NL80211_ATTR_USE_RRM] = { .type = NLA_FLAG },
+	[NL80211_ATTR_TSID] = { .type = NLA_U8 },
+	[NL80211_ATTR_USER_PRIO] = { .type = NLA_U8 },
+	[NL80211_ATTR_ADMITTED_TIME] = { .type = NLA_U16 },
 };
 
 /* policy for the key attributes */
@@ -1510,6 +1513,9 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 			if (rdev->wiphy.flags & WIPHY_FLAG_HAS_CHANNEL_SWITCH)
 				CMD(channel_switch, CHANNEL_SWITCH);
 			CMD(set_qos_map, SET_QOS_MAP);
+			if (rdev->wiphy.flags &
+					WIPHY_FLAG_SUPPORTS_WMM_ADMISSION)
+				CMD(add_tx_ts, ADD_TX_TS);
 		}
 		/* add into the if now */
 #undef CMD
@@ -9390,6 +9396,93 @@ static int nl80211_set_qos_map(struct sk_buff *skb,
 	return ret;
 }
 
+static int nl80211_add_tx_ts(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];
+	struct wireless_dev *wdev = dev->ieee80211_ptr;
+	const u8 *peer;
+	u8 tsid, up;
+	u16 admitted_time = 0;
+	int err;
+
+	if (!(rdev->wiphy.flags & WIPHY_FLAG_SUPPORTS_WMM_ADMISSION))
+		return -EOPNOTSUPP;
+
+	if (!info->attrs[NL80211_ATTR_TSID] || !info->attrs[NL80211_ATTR_MAC] ||
+	    !info->attrs[NL80211_ATTR_USER_PRIO])
+		return -EINVAL;
+
+	tsid = nla_get_u8(info->attrs[NL80211_ATTR_TSID]);
+	if (tsid >= IEEE80211_NUM_TIDS)
+		return -EINVAL;
+
+	up = nla_get_u8(info->attrs[NL80211_ATTR_USER_PRIO]);
+	if (up >= IEEE80211_NUM_UPS)
+		return -EINVAL;
+
+	/* WMM uses TIDs 0-7 even for TSPEC */
+	if (tsid < IEEE80211_FIRST_TSPEC_TSID) {
+		if (!(rdev->wiphy.flags & WIPHY_FLAG_SUPPORTS_WMM_ADMISSION))
+			return -EINVAL;
+	} else {
+		/* TODO: handle 802.11 TSPEC/admission control
+		 * need more attributes for that (e.g. BA session requirement)
+		 */
+		return -EINVAL;
+	}
+
+	peer = nla_data(info->attrs[NL80211_ATTR_MAC]);
+
+	if (info->attrs[NL80211_ATTR_ADMITTED_TIME]) {
+		admitted_time =
+			nla_get_u16(info->attrs[NL80211_ATTR_ADMITTED_TIME]);
+		if (!admitted_time)
+			return -EINVAL;
+	}
+
+	wdev_lock(wdev);
+	switch (wdev->iftype) {
+	case NL80211_IFTYPE_STATION:
+	case NL80211_IFTYPE_P2P_CLIENT:
+		if (wdev->current_bss)
+			break;
+		err = -ENOTCONN;
+		goto out;
+	default:
+		err = -EOPNOTSUPP;
+		goto out;
+	}
+
+	err = rdev_add_tx_ts(rdev, dev, tsid, peer, up, admitted_time);
+
+ out:
+	wdev_unlock(wdev);
+	return err;
+}
+
+static int nl80211_del_tx_ts(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];
+	struct wireless_dev *wdev = dev->ieee80211_ptr;
+	const u8 *peer;
+	u8 tsid;
+	int err;
+
+	if (!info->attrs[NL80211_ATTR_TSID] || !info->attrs[NL80211_ATTR_MAC])
+		return -EINVAL;
+
+	tsid = nla_get_u8(info->attrs[NL80211_ATTR_TSID]);
+	peer = nla_data(info->attrs[NL80211_ATTR_MAC]);
+
+	wdev_lock(wdev);
+	err = rdev_del_tx_ts(rdev, dev, tsid, peer);
+	wdev_unlock(wdev);
+
+	return err;
+}
+
 #define NL80211_FLAG_NEED_WIPHY		0x01
 #define NL80211_FLAG_NEED_NETDEV	0x02
 #define NL80211_FLAG_NEED_RTNL		0x04
@@ -10147,6 +10240,22 @@ static const struct genl_ops nl80211_ops[] = {
 		.internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
 				  NL80211_FLAG_NEED_RTNL,
 	},
+	{
+		.cmd = NL80211_CMD_ADD_TX_TS,
+		.doit = nl80211_add_tx_ts,
+		.policy = nl80211_policy,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+				  NL80211_FLAG_NEED_RTNL,
+	},
+	{
+		.cmd = NL80211_CMD_DEL_TX_TS,
+		.doit = nl80211_del_tx_ts,
+		.policy = nl80211_policy,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+				  NL80211_FLAG_NEED_RTNL,
+	},
 };
 
 /* notification functions */

net/wireless/rdev-ops.h

@@ -915,4 +915,35 @@ rdev_set_ap_chanwidth(struct cfg80211_registered_device *rdev,
 	return ret;
 }
 
+static inline int
+rdev_add_tx_ts(struct cfg80211_registered_device *rdev,
+	       struct net_device *dev, u8 tsid, const u8 *peer,
+	       u8 user_prio, u16 admitted_time)
+{
+	int ret = -EOPNOTSUPP;
+
+	trace_rdev_add_tx_ts(&rdev->wiphy, dev, tsid, peer,
+			     user_prio, admitted_time);
+	if (rdev->ops->add_tx_ts)
+		ret = rdev->ops->add_tx_ts(&rdev->wiphy, dev, tsid, peer,
+					   user_prio, admitted_time);
+	trace_rdev_return_int(&rdev->wiphy, ret);
+
+	return ret;
+}
+
+static inline int
+rdev_del_tx_ts(struct cfg80211_registered_device *rdev,
+	       struct net_device *dev, u8 tsid, const u8 *peer)
+{
+	int ret = -EOPNOTSUPP;
+
+	trace_rdev_del_tx_ts(&rdev->wiphy, dev, tsid, peer);
+	if (rdev->ops->del_tx_ts)
+		ret = rdev->ops->del_tx_ts(&rdev->wiphy, dev, tsid, peer);
+	trace_rdev_return_int(&rdev->wiphy, ret);
+
+	return ret;
+}
+
 #endif /* __CFG80211_RDEV_OPS */

net/wireless/trace.h

@@ -1896,6 +1896,51 @@ TRACE_EVENT(rdev_set_ap_chanwidth,
 		  WIPHY_PR_ARG, NETDEV_PR_ARG, CHAN_DEF_PR_ARG)
 );
 
+TRACE_EVENT(rdev_add_tx_ts,
+	TP_PROTO(struct wiphy *wiphy, struct net_device *netdev,
+		 u8 tsid, const u8 *peer, u8 user_prio, u16 admitted_time),
+	TP_ARGS(wiphy, netdev, tsid, peer, user_prio, admitted_time),
+	TP_STRUCT__entry(
+		WIPHY_ENTRY
+		NETDEV_ENTRY
+		MAC_ENTRY(peer)
+		__field(u8, tsid)
+		__field(u8, user_prio)
+		__field(u16, admitted_time)
+	),
+	TP_fast_assign(
+		WIPHY_ASSIGN;
+		NETDEV_ASSIGN;
+		MAC_ASSIGN(peer, peer);
+		__entry->tsid = tsid;
+		__entry->user_prio = user_prio;
+		__entry->admitted_time = admitted_time;
+	),
+	TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", " MAC_PR_FMT ", TSID %d, UP %d, time %d",
+		  WIPHY_PR_ARG, NETDEV_PR_ARG, MAC_PR_ARG(peer),
+		  __entry->tsid, __entry->user_prio, __entry->admitted_time)
+);
+
+TRACE_EVENT(rdev_del_tx_ts,
+	TP_PROTO(struct wiphy *wiphy, struct net_device *netdev,
+		 u8 tsid, const u8 *peer),
+	TP_ARGS(wiphy, netdev, tsid, peer),
+	TP_STRUCT__entry(
+		WIPHY_ENTRY
+		NETDEV_ENTRY
+		MAC_ENTRY(peer)
+		__field(u8, tsid)
+	),
+	TP_fast_assign(
+		WIPHY_ASSIGN;
+		NETDEV_ASSIGN;
+		MAC_ASSIGN(peer, peer);
+		__entry->tsid = tsid;
+	),
+	TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", " MAC_PR_FMT ", TSID %d",
+		  WIPHY_PR_ARG, NETDEV_PR_ARG, MAC_PR_ARG(peer), __entry->tsid)
+);
+
 /*************************************************************
  *	     cfg80211 exported functions traces		     *
  *************************************************************/