wifi: only try adding supplicant interface 5 times on errors (bgo #753971)

When wpa_supplicant keeps returning an error, NetworkManager was trying over
and over again. Which resulted in endless messages:
<error> [1448462154.584916] [supplicant-manager/nm-supplicant-interface.c:879] interface_add_cb(): (AAA): error adding interface: wpa_supplicant couldn't grab this interface.
NetworkManager[17073]: <info>  (AAA): supplicant interface state: starting -> down

Testcase:
$ iw list | grep -A 3 "interface combinations"
	interface combinations are not supported
	HT Capability overrides:
		 * MCS: ff ff ff ff ff ff ff ff ff ff
		 * maximum A-MSDU length
$ sudo iw wlan0 interface add AAA type managed
...
$ sudo iw dev AAA del

Fixes: 3a2e6de0d30217753c825ba1f20e589c1f647780

https://bugzilla.gnome.org/show_bug.cgi?id=753971

(cherry picked from commit 7e93ceb6408cd9345222066ade3f76cc38ad7db3)

1 files changed, 36 insertions, 1 deletions

diff --git a/src/devices/wifi/nm-device-wifi.c b/src/devices/wifi/nm-device-wifi.c
index 15d41206a1..db78fb4c57 100644
--- a/src/devices/wifi/nm-device-wifi.c
+++ b/src/devices/wifi/nm-device-wifi.c
@@ -136,6 +136,8 @@ struct _NMDeviceWifiPrivate {
 	guint32           failed_link_count;
 	guint             periodic_source_id;
 	guint             link_timeout_id;
+	guint32           failed_iface_count;
+	guint             reacquire_iface_id;
 
 	NMDeviceWifiCapabilities capabilities;
 };
@@ -1959,6 +1961,15 @@ cleanup_association_attempt (NMDeviceWifi *self, gboolean disconnect)
 }
 
 static void
+cleanup_supplicant_failures (NMDeviceWifi *self)
+{
+	NMDeviceWifiPrivate *priv = NM_DEVICE_WIFI_GET_PRIVATE (self);
+
+	nm_clear_g_source (&priv->reacquire_iface_id);
+	priv->failed_iface_count = 0;
+}
+
+static void
 wifi_secrets_cb (NMActRequest *req,
                  guint32 call_id,
                  NMConnection *connection,
@@ -2158,6 +2169,24 @@ handle_8021x_or_psk_auth_fail (NMDeviceWifi *self,
 	return handled;
 }
 
+static gboolean
+reacquire_interface_cb (gpointer user_data)
+{
+	NMDevice *device = NM_DEVICE (user_data);
+	NMDeviceWifi *self = NM_DEVICE_WIFI (device);
+	NMDeviceWifiPrivate *priv = NM_DEVICE_WIFI_GET_PRIVATE (self);
+
+	priv->reacquire_iface_id = 0;
+	priv->failed_iface_count++;
+
+	_LOGW (LOGD_WIFI, "re-acquiring supplicant interface (#%d).", priv->failed_iface_count);
+
+	if (!priv->sup_iface)
+		supplicant_interface_acquire (self);
+
+	return G_SOURCE_REMOVE;
+}
+
 static void
 supplicant_iface_state_cb (NMSupplicantInterface *iface,
                            guint32 new_state,
@@ -2264,7 +2293,10 @@ supplicant_iface_state_cb (NMSupplicantInterface *iface,
 		 * ready if the supplicant comes back.
 		 */
 		supplicant_interface_release (self);
-		supplicant_interface_acquire (self);
+		if (priv->failed_iface_count < 5)
+			priv->reacquire_iface_id = g_timeout_add_seconds (10, reacquire_interface_cb, self);
+		else
+			_LOGI (LOGD_DEVICE | LOGD_WIFI, "supplicant interface keeps failing, giving up");
 		break;
 	default:
 		break;
@@ -3061,6 +3093,7 @@ device_state_changed (NMDevice *device,
 		}
 
 		cleanup_association_attempt (self, TRUE);
+		cleanup_supplicant_failures (self);
 		remove_all_aps (self);
 	}
 
@@ -3147,6 +3180,7 @@ set_enabled (NMDevice *device, gboolean enabled)
 		}
 
 		/* Re-initialize the supplicant interface and wait for it to be ready */
+		cleanup_supplicant_failures (self);
 		if (priv->sup_iface)
 			supplicant_interface_release (self);
 		supplicant_interface_acquire (self);
@@ -3201,6 +3235,7 @@ dispose (GObject *object)
 
 	cleanup_association_attempt (self, TRUE);
 	supplicant_interface_release (self);
+	cleanup_supplicant_failures (self);
 
 	g_clear_object (&priv->sup_mgr);