[PATCH 3/6] netdev: add critical signal threshold level

[James Prestwood <prestwoj@gmail.com>]

This adds a secondary set of signal thresholds. The purpose of these
are to provide more flexibility in how IWD roams. The critical
threshold is intended to be temporary and is automatically reset
upon any connection changes: disconnects, roams, or new connections.
---
 src/netdev.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 src/netdev.h |  2 ++
 2 files changed, 53 insertions(+)

diff --git a/src/netdev.c b/src/netdev.c
index db1ad380..852ad569 100644
--- a/src/netdev.c
+++ b/src/netdev.c
@@ -212,6 +212,8 @@ static bool mac_per_ssid;
 /* Threshold RSSI for roaming to trigger, configurable in main.conf */
 static int LOW_SIGNAL_THRESHOLD;
 static int LOW_SIGNAL_THRESHOLD_5GHZ;
+static int CRITICAL_SIGNAL_THRESHOLD;
+static int CRITICAL_SIGNAL_THRESHOLD_5GHZ;
 
 static unsigned int iov_ie_append(struct iovec *iov,
 					unsigned int n_iov, unsigned int c,
@@ -841,6 +843,10 @@ static void netdev_connect_free(struct netdev *netdev)
 		l_genl_family_cancel(nl80211, netdev->get_oci_cmd_id);
 		netdev->get_oci_cmd_id = 0;
 	}
+
+	/* Reset thresholds back to default */
+	netdev->low_signal_threshold = LOW_SIGNAL_THRESHOLD;
+	netdev->low_signal_threshold_5ghz = LOW_SIGNAL_THRESHOLD_5GHZ;
 }
 
 static void netdev_connect_failed(struct netdev *netdev,
@@ -3674,6 +3680,39 @@ static int netdev_cqm_rssi_update(struct netdev *netdev)
 	return 0;
 }
 
+static int netdev_set_signal_thresholds(struct netdev *netdev, int threshold,
+					int threshold_5ghz)
+{
+	int current = netdev->frequency > 4000 ?
+					netdev->low_signal_threshold_5ghz :
+					netdev->low_signal_threshold;
+	int new = netdev->frequency > 4000 ? threshold_5ghz : threshold;
+
+	if (current == new)
+		return -EALREADY;
+
+	l_debug("changing low signal threshold to %d", new);
+
+	netdev->low_signal_threshold = threshold;
+	netdev->low_signal_threshold_5ghz = threshold_5ghz;
+
+	netdev_cqm_rssi_update(netdev);
+
+	return 0;
+}
+
+int netdev_lower_signal_threshold(struct netdev *netdev)
+{
+	return netdev_set_signal_thresholds(netdev, CRITICAL_SIGNAL_THRESHOLD,
+						CRITICAL_SIGNAL_THRESHOLD_5GHZ);
+}
+
+int netdev_raise_signal_threshold(struct netdev *netdev)
+{
+	return netdev_set_signal_thresholds(netdev, LOW_SIGNAL_THRESHOLD,
+						LOW_SIGNAL_THRESHOLD_5GHZ);
+}
+
 static bool netdev_connection_work_ready(struct wiphy_radio_work_item *item)
 {
 	struct netdev *netdev = l_container_of(item, struct netdev, work);
@@ -3884,6 +3923,8 @@ build_cmd_connect:
 	netdev->handshake = hs;
 	netdev->sm = sm;
 	netdev->cur_rssi = bss->signal_strength / 100;
+	netdev->low_signal_threshold = LOW_SIGNAL_THRESHOLD;
+	netdev->low_signal_threshold_5ghz = LOW_SIGNAL_THRESHOLD_5GHZ;
 
 	if (netdev->rssi_levels_num)
 		netdev_set_rssi_level_idx(netdev);
@@ -4257,6 +4298,8 @@ int netdev_ft_reassociate(struct netdev *netdev,
 	netdev->event_filter = event_filter;
 	netdev->connect_cb = cb;
 	netdev->user_data = user_data;
+	netdev->low_signal_threshold = LOW_SIGNAL_THRESHOLD;
+	netdev->low_signal_threshold_5ghz = LOW_SIGNAL_THRESHOLD_5GHZ;
 
 	/*
 	 * Cancel commands that could be running because of EAPoL activity
@@ -6279,6 +6322,14 @@ static int netdev_init(void)
 					&LOW_SIGNAL_THRESHOLD_5GHZ))
 		LOW_SIGNAL_THRESHOLD_5GHZ = -76;
 
+	if (!l_settings_get_int(settings, "General", "CriticalRoamThreshold",
+					&CRITICAL_SIGNAL_THRESHOLD))
+		CRITICAL_SIGNAL_THRESHOLD = -80;
+
+	if (!l_settings_get_int(settings, "General", "CriticalRoamThreshold5G",
+					&CRITICAL_SIGNAL_THRESHOLD_5GHZ))
+		CRITICAL_SIGNAL_THRESHOLD_5GHZ = -82;
+
 	rand_addr_str = l_settings_get_value(settings, "General",
 						"AddressRandomization");
 	if (rand_addr_str && !strcmp(rand_addr_str, "network"))
diff --git a/src/netdev.h b/src/netdev.h
index db0440d0..3a772256 100644
--- a/src/netdev.h
+++ b/src/netdev.h
@@ -197,6 +197,8 @@ int netdev_neighbor_report_req(struct netdev *netdev,
 
 int netdev_set_rssi_report_levels(struct netdev *netdev, const int8_t *levels,
 					size_t levels_num);
+int netdev_lower_signal_threshold(struct netdev *netdev);
+int netdev_raise_signal_threshold(struct netdev *netdev);
 
 int netdev_get_station(struct netdev *netdev, const uint8_t *mac,
 			netdev_get_station_cb_t cb, void *user_data,
-- 
2.34.1