Set WiFi signal strength based on the reported ranges

The semantics of the scan results level and quality change with kernel
versions and/or drivers. We now fetch the wireless extensions ranges
first and compute our signal strength based on that.

diff --git a/plugins/supplicant.c b/plugins/supplicant.c
index 5a68231..86108c9 100644 (file)
--- a/plugins/supplicant.c
+++ b/plugins/supplicant.c
@@ -24,9 +24,14 @@
 #endif
 
 #include <stdio.h>
+#include <unistd.h>
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <linux/if_arp.h>
+#include <linux/wireless.h>
 #include <net/ethernet.h>
 
 #include <gdbus.h>
@@ -178,6 +183,7 @@ struct supplicant_task {
        enum supplicant_state state;
        gboolean noscan;
        GSList *scan_results;
+       struct iw_range *range;
 };
 
 static GSList *task_list = NULL;
@@ -1016,9 +1022,10 @@ static void extract_capabilites(DBusMessageIter *value,
                result->has_wep = TRUE;
 }
 
-static unsigned char calculate_strength(struct supplicant_result *result)
+static unsigned char calculate_strength(struct supplicant_task *task,
+                                       struct supplicant_result *result)
 {
-       if (result->quality < 0) {
+       if (task->range->max_qual.qual == 0) {
                unsigned char strength;
 
                if (result->level > 0)
@@ -1032,7 +1039,7 @@ static unsigned char calculate_strength(struct supplicant_result *result)
                return strength;
        }
 
-       return result->quality;
+       return (result->quality * 100) / task->range->max_qual.qual;
 }
 
 static unsigned short calculate_channel(struct supplicant_result *result)
@@ -1146,7 +1153,7 @@ static void properties_reply(DBusPendingCall *call, void *user_data)
        else if (result.frequency == 14)
                result.frequency = 2484;
 
-       strength = calculate_strength(&result);
+       strength = calculate_strength(task, &result);
        channel  = calculate_channel(&result);
 
        frequency = (result.frequency < 0) ? 0 : result.frequency;
@@ -1486,9 +1493,31 @@ static DBusHandlerResult supplicant_filter(DBusConnection *conn,
        return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 }
 
+static int supplicant_get_range(struct supplicant_task *task)
+{
+       int fd, ret;
+       struct iwreq wrq;
+
+       fd = socket(PF_INET, SOCK_DGRAM, 0);
+       if (fd < 0)
+               return -errno;
+
+       memset(&wrq, 0, sizeof(struct iwreq));
+       strncpy(wrq.ifr_name, task->ifname, IFNAMSIZ);
+       wrq.u.data.pointer = task->range;
+       wrq.u.data.length = sizeof(struct iw_range);
+
+       ret = ioctl(fd, SIOCGIWRANGE, &wrq);
+
+       close(fd);
+
+       return ret;
+}
+
 int supplicant_start(struct connman_device *device)
 {
        struct supplicant_task *task;
+       int err;
 
        DBG("device %p", device);
 
@@ -1500,10 +1529,20 @@ int supplicant_start(struct connman_device *device)
        task->ifname = connman_inet_ifname(task->ifindex);
 
        if (task->ifname == NULL) {
-               g_free(task);
-               return -ENOMEM;
+               err = -ENOMEM;
+               goto err_ifname;
        }
 
+       task->range = g_try_malloc0(sizeof(struct iw_range));
+       if (task->range == NULL) {
+               err = -ENOMEM;
+               goto err_range;
+       }
+
+       err = supplicant_get_range(task);
+       if (err)
+               goto err_get_range;
+
        task->device = connman_device_ref(device);
 
        task->created = FALSE;
@@ -1513,6 +1552,17 @@ int supplicant_start(struct connman_device *device)
        task_list = g_slist_append(task_list, task);
 
        return create_interface(task);
+
+err_get_range:
+       g_free(task->range);
+
+err_range:
+       g_free(task->ifname);
+
+err_ifname:
+       g_free(task);
+
+       return err;
 }
 
 int supplicant_stop(struct connman_device *device)
@@ -1526,6 +1576,8 @@ int supplicant_stop(struct connman_device *device)
        if (task == NULL)
                return -ENODEV;
 
+       g_free(task->range);
+
        task_list = g_slist_remove(task_list, task);
 
        disable_network(task);