mac80211_hwsim: add PMSR abort support via virtio

PMSR (a.k.a. peer measurement) is generalized measurement between two
devices with Wi-Fi support. And currently FTM (a.k.a. fine time
measurement or flight time measurement) is the one and only measurement.

Add necessary functionalities for mac80211_hwsim to abort previous PMSR
request. The abortion request is sent to the wmedium where the PMSR request
is actually handled.

In detail, add new mac80211_hwsim command HWSIM_CMD_ABORT_PMSR. When
mac80211_hwsim receives the PMSR abortion request via
ieee80211_ops.abort_pmsr, the received cfg80211_pmsr_request is resent to
the wmediumd with command HWSIM_CMD_ABORT_PMSR and attribute
HWSIM_ATTR_PMSR_REQUEST. The attribute is formatted as the same way as
nl80211_pmsr_start() expects.

Signed-off-by: Jaewan Kim <jaewan@google.com>
Link: https://lore.kernel.org/r/20230322131637.2633968-5-jaewan@google.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/virtual/mac80211_hwsim.c

@@ -3377,6 +3377,67 @@ static int mac80211_hwsim_start_pmsr(struct ieee80211_hw *hw,
 	return err;
 }
 
+static void mac80211_hwsim_abort_pmsr(struct ieee80211_hw *hw,
+				      struct ieee80211_vif *vif,
+				      struct cfg80211_pmsr_request *request)
+{
+	struct mac80211_hwsim_data *data;
+	struct sk_buff *skb = NULL;
+	struct nlattr *pmsr;
+	void *msg_head;
+	u32 _portid;
+	int err = 0;
+
+	data = hw->priv;
+	_portid = READ_ONCE(data->wmediumd);
+	if (!_portid && !hwsim_virtio_enabled)
+		return;
+
+	mutex_lock(&data->mutex);
+
+	if (data->pmsr_request != request) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!skb) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	msg_head = genlmsg_put(skb, 0, 0, &hwsim_genl_family, 0, HWSIM_CMD_ABORT_PMSR);
+
+	if (nla_put(skb, HWSIM_ATTR_ADDR_TRANSMITTER, ETH_ALEN, data->addresses[1].addr))
+		goto out;
+
+	pmsr = nla_nest_start(skb, HWSIM_ATTR_PMSR_REQUEST);
+	if (!pmsr) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	err = mac80211_hwsim_send_pmsr_request(skb, request);
+	if (err)
+		goto out;
+
+	err = nla_nest_end(skb, pmsr);
+	if (err)
+		goto out;
+
+	genlmsg_end(skb, msg_head);
+	if (hwsim_virtio_enabled)
+		hwsim_tx_virtio(data, skb);
+	else
+		hwsim_unicast_netgroup(data, skb, _portid);
+
+out:
+	if (err && skb)
+		nlmsg_free(skb);
+
+	mutex_unlock(&data->mutex);
+}
+
 #define HWSIM_COMMON_OPS					\
 	.tx = mac80211_hwsim_tx,				\
 	.wake_tx_queue = ieee80211_handle_wake_tx_queue,	\
@@ -3401,6 +3462,7 @@ static int mac80211_hwsim_start_pmsr(struct ieee80211_hw *hw,
 	.get_et_stats = mac80211_hwsim_get_et_stats,		\
 	.get_et_strings = mac80211_hwsim_get_et_strings,	\
 	.start_pmsr = mac80211_hwsim_start_pmsr,		\
+	.abort_pmsr = mac80211_hwsim_abort_pmsr,
 
 #define HWSIM_NON_MLO_OPS					\
 	.sta_add = mac80211_hwsim_sta_add,			\

drivers/net/wireless/virtual/mac80211_hwsim.h

@@ -83,6 +83,7 @@ enum hwsim_tx_control_flags {
  *	are the same as to @HWSIM_CMD_ADD_MAC_ADDR.
  * @HWSIM_CMD_START_PMSR: request to start peer measurement with the
  *	%HWSIM_ATTR_PMSR_REQUEST.
+ * @HWSIM_CMD_ABORT_PMSR: abort previously sent peer measurement
  * @__HWSIM_CMD_MAX: enum limit
  */
 enum {
@@ -96,6 +97,7 @@ enum {
 	HWSIM_CMD_ADD_MAC_ADDR,
 	HWSIM_CMD_DEL_MAC_ADDR,
 	HWSIM_CMD_START_PMSR,
+	HWSIM_CMD_ABORT_PMSR,
 	__HWSIM_CMD_MAX,
 };
 #define HWSIM_CMD_MAX (_HWSIM_CMD_MAX - 1)