We were having a problem with our wifi scanning, where the list of wifi available would become empty and would not be repopulated until after a long delay. Researching the problem it seemed that it was related to BSS expiration age. There were already some people who had faced the same issue, so inspired by this we developed the following patch which allows us to set the BSS expiration age to match ConnMan long scanning interval to avoid the loss of networks during a long interval between two scans. diff --git a/gsupplicant/gsupplicant.h b/gsupplicant/gsupplicant.h index bfb52db..08d6b9e 100644 --- a/gsupplicant/gsupplicant.h +++ b/gsupplicant/gsupplicant.h @@ -267,7 +267,8 @@ int g_supplicant_interface_connect(GSupplicantInterface *interface, int g_supplicant_interface_disconnect(GSupplicantInterface *interface, GSupplicantInterfaceCallback callback, void *user_data); - +int g_supplicant_interface_set_bss_expiration_age(GSupplicantInterface *interface, + unsigned int bss_expiration_age); int g_supplicant_interface_set_apscan(GSupplicantInterface *interface, unsigned int ap_scan); diff --git a/gsupplicant/supplicant.c b/gsupplicant/supplicant.c index 6052f7b..fe6ad48 100644 --- a/gsupplicant/supplicant.c +++ b/gsupplicant/supplicant.c @@ -981,6 +981,46 @@ static void interface_capability(const char *key, DBusMessageIter *iter, key, dbus_message_iter_get_arg_type(iter)); } +struct g_supplicant_bss_expiration_age +{ + GSupplicantInterface *interface; + unsigned int bss_expiration_age; +}; + +static void set_bss_expiration_age(DBusMessageIter *iter, void *user_data) +{ + struct g_supplicant_bss_expiration_age *data = user_data; + unsigned int bss_expiration_age = data->bss_expiration_age; + + dbus_free(data); + dbus_message_iter_append_basic(iter, DBUS_TYPE_UINT32, &bss_expiration_age); +} + +int g_supplicant_interface_set_bss_expiration_age(GSupplicantInterface *interface, + unsigned int bss_expiration_age) +{ + struct g_supplicant_bss_expiration_age *data; + int ret; + + data = dbus_malloc0(sizeof(*data)); + + if (!data) + return -ENOMEM; + + data->bss_expiration_age = bss_expiration_age; + data->interface = interface; + + ret = supplicant_dbus_property_set(interface->path, + SUPPLICANT_INTERFACE ".Interface", + "BSSExpireAge", DBUS_TYPE_UINT32_AS_STRING, + set_bss_expiration_age, NULL, data, NULL); + if (ret < 0) + dbus_free(data); + + return ret; +} + + struct set_apscan_data { unsigned int ap_scan; diff --git a/plugins/wifi.c b/plugins/wifi.c index 910b739..57b63e2 100644 --- a/plugins/wifi.c +++ b/plugins/wifi.c @@ -1522,6 +1522,7 @@ static void interface_create_callback(int result, void *user_data) { struct wifi_data *wifi = user_data; + char * bgscan_range_max; DBG("result %d ifname %s, wifi %p", result, g_supplicant_interface_get_ifname(interface), @@ -1537,6 +1538,13 @@ static void interface_create_callback(int result, wifi->interface_ready = true; finalize_interface_creation(wifi); } + /* Force the BSS expiration age to match ConnMan long scanning interval to avoid the loss of networks during a long interval between two scannings. */ + if ((bgscan_range_max = strrchr(BGSCAN_DEFAULT,':')) != NULL && + g_supplicant_interface_set_bss_expiration_age(interface, strtol(bgscan_range_max + 1, (char**)NULL, 10) + 10) >= 0) { + DBG("bss expiration age successfully updated"); + } else { + DBG("bss expiration age update has failed"); + } } static int wifi_enable(struct connman_device *device)