wifi: use supplicant's CurrentBSS as the current AP

Instead of keeping track of it internally, and attempting to fuzzy-match
access points and stuff, just use the supplicant's information.  If the
supplicant doesn't know what AP it's talking to, then we've got more
problems than just NM code.

The theory here is that when starting activation, we'll use the given
access point from the scan list that the supplicant already knows about.
If there isn't one yet (adhoc, hidden, or AP mode) then we'll create
a fake AP and add it to the scan list.

Once the supplicant has associated to the AP, it'll notify about the
current BSS which we then look up in the scan list, and set
priv->current AP to that.  If for some reason the given AP isn't yet
in our scan list (which often happens for adhoc/AP) then we'll just
live with the fake AP until we get the scan result, which should happen
very soon.

We don't need to do any fuzzy-matching to find the current AP because
it will either always be one the supplicant knows about, or a fake one
that the supplicant doesn't know about that will be replaced soon anyway.

1 files changed, 96 insertions, 251 deletions

diff --git a/src/devices/wifi/nm-device-wifi.c b/src/devices/wifi/nm-device-wifi.c
index e46bcafa6e..c14749a8ab 100644
--- a/src/devices/wifi/nm-device-wifi.c
+++ b/src/devices/wifi/nm-device-wifi.c
@@ -42,6 +42,7 @@
 #include "nm-device-private.h"
 #include "nm-utils.h"
 #include "nm-logging.h"
+#include "gsystem-local-alloc.h"
 #include "NetworkManagerUtils.h"
 #include "nm-activation-request.h"
 #include "nm-supplicant-manager.h"
@@ -183,6 +184,10 @@ static void supplicant_iface_notify_scanning_cb (NMSupplicantInterface * iface,
                                                  GParamSpec * pspec,
                                                  NMDeviceWifi * self);
 
+static void supplicant_iface_notify_current_bss (NMSupplicantInterface *iface,
+                                                 GParamSpec *pspec,
+                                                 NMDeviceWifi *self);
+
 static void schedule_scanlist_cull (NMDeviceWifi *self);
 
 static gboolean request_wireless_scan (gpointer user_data);
@@ -274,6 +279,10 @@ supplicant_interface_acquire (NMDeviceWifi *self)
 	                  "notify::scanning",
 	                  G_CALLBACK (supplicant_iface_notify_scanning_cb),
 	                  self);
+	g_signal_connect (priv->sup_iface,
+	                  "notify::" NM_SUPPLICANT_INTERFACE_CURRENT_BSS,
+	                  G_CALLBACK (supplicant_iface_notify_current_bss),
+	                  self);
 
 	return TRUE;
 }
@@ -337,145 +346,6 @@ get_ap_by_supplicant_path (NMDeviceWifi *self, const char *path)
 	return NULL;
 }
 
-static NMAccessPoint *
-find_active_ap (NMDeviceWifi *self,
-                NMAccessPoint *ignore_ap,
-                gboolean match_hidden)
-{
-	NMDeviceWifiPrivate *priv = NM_DEVICE_WIFI_GET_PRIVATE (self);
-	int ifindex = nm_device_get_ifindex (NM_DEVICE (self));
-	guint8 bssid[ETH_ALEN];
-	GByteArray *ssid;
-	int i = 0;
-	NMAccessPoint *match_nofreq = NULL, *active_ap = NULL;
-	gboolean found_a_band = FALSE;
-	gboolean found_bg_band = FALSE;
-	NM80211Mode devmode;
-	guint32 devfreq;
-
-	nm_platform_wifi_get_bssid (ifindex, bssid);
-	_LOGT (LOGD_WIFI, "active BSSID: %02x:%02x:%02x:%02x:%02x:%02x",
-	       bssid[0], bssid[1], bssid[2], bssid[3], bssid[4], bssid[5]);
-
-	if (!nm_ethernet_address_is_valid (bssid, ETH_ALEN))
-		return NULL;
-
-	ssid = nm_platform_wifi_get_ssid (ifindex);
-	_LOGT (LOGD_WIFI, "active SSID: %s%s%s",
-	       ssid ? "'" : "",
-	       ssid ? nm_utils_escape_ssid (ssid->data, ssid->len) : "(none)",
-	       ssid ? "'" : "");
-
-	devmode = nm_platform_wifi_get_mode (ifindex);
-	devfreq = nm_platform_wifi_get_frequency (ifindex);
-
-	/* When matching hidden APs, do a second pass that ignores the SSID check,
-	 * because NM might not yet know the SSID of the hidden AP in the scan list
-	 * and therefore it won't get matched the first time around.
-	 */
-	while (i++ < (match_hidden ? 2 : 1)) {
-		GHashTableIter iter;
-		NMAccessPoint *ap;
-
-		_LOGT (LOGD_WIFI, "  Pass #%d %s", i, i > 1 ? "(ignoring SSID)" : "");
-
-		/* Find this SSID + BSSID in the device's AP list */
-		g_hash_table_iter_init (&iter, priv->aps);
-		while (g_hash_table_iter_next (&iter, NULL, (gpointer) &ap)) {
-			const char *ap_bssid = nm_ap_get_address (ap);
-			const GByteArray *ap_ssid = nm_ap_get_ssid (ap);
-			NM80211Mode apmode;
-			guint32 apfreq;
-
-			_LOGT (LOGD_WIFI, "    AP: %s%s%s  %s",
-			       ap_ssid ? "'" : "",
-			       ap_ssid ? nm_utils_escape_ssid (ap_ssid->data, ap_ssid->len) : "(none)",
-			       ap_ssid ? "'" : "",
-			       str_if_set (ap_bssid, "(none)"));
-
-			if (ap == ignore_ap) {
-				_LOGT (LOGD_WIFI, "      ignored");
-				continue;
-			}
-
-			if (!nm_utils_hwaddr_matches (bssid, ETH_ALEN, ap_bssid, -1)) {
-				_LOGT (LOGD_WIFI, "      BSSID mismatch");
-				continue;
-			}
-
-			if (i == 0) {
-				if (   (ssid && !ap_ssid)
-				    || (ap_ssid && !ssid)
-				    || (ssid && ap_ssid && !nm_utils_same_ssid (ssid->data, ssid->len,
-				                                                ap_ssid->data, ap_ssid->len,
-				                                                TRUE))) {
-					_LOGT (LOGD_WIFI, "      SSID mismatch");
-					continue;
-				}
-			}
-
-			apmode = nm_ap_get_mode (ap);
-			if (devmode != apmode) {
-				_LOGT (LOGD_WIFI, "      mode mismatch (device %d, ap %d)",
-				       devmode, apmode);
-				continue;
-			}
-
-			apfreq = nm_ap_get_freq (ap);
-			if (devfreq != apfreq) {
-				_LOGT (LOGD_WIFI, "      frequency mismatch (device %u, ap %u)",
-				       devfreq, apfreq);
-
-				if (match_nofreq == NULL)
-					match_nofreq = ap;
-
-				if (apfreq > 4000)
-					found_a_band = TRUE;
-				else if (apfreq > 2000)
-					found_bg_band = TRUE;
-				continue;
-			}
-
-			// FIXME: handle security settings here too
-			_LOGT (LOGD_WIFI, "      matched");
-			active_ap = ap;
-			goto done;
-		}
-	}
-
-	/* Some proprietary drivers (wl.o) report tuned frequency (like when
-	 * scanning) instead of the associated AP's frequency.  This is a great
-	 * example of how WEXT is underspecified.  We use frequency to find the
-	 * active AP in the scan list because some configurations use the same
-	 * SSID/BSSID on the 2GHz and 5GHz bands simultaneously, and we need to
-	 * make sure we get the right AP in the right band.  This configuration
-	 * is uncommon though, and the frequency check penalizes closed drivers we
-	 * can't fix.  Because we're not total dicks, ignore the frequency condition
-	 * if the associated BSSID/SSID exists only in one band since that's most
-	 * likely the AP we want.  Sometimes wl.o returns a frequency of 0, so if
-	 * we can't match the AP based on frequency at all, just give up.
-	 */
-	if (match_nofreq && ((found_a_band != found_bg_band) || (devfreq == 0))) {
-		const GByteArray *ap_ssid = nm_ap_get_ssid (match_nofreq);
-
-		_LOGT (LOGD_WIFI, "    matched %s%s%s  %s",
-		       ap_ssid ? "'" : "",
-		       ap_ssid ? nm_utils_escape_ssid (ap_ssid->data, ap_ssid->len) : "(none)",
-		       ap_ssid ? "'" : "",
-		       str_if_set (nm_ap_get_address (match_nofreq), "(none)"));
-
-		active_ap = match_nofreq;
-		goto done;
-	}
-
-	_LOGT (LOGD_WIFI, "  No matching AP found.");
-
-done:
-	if (ssid)
-		g_byte_array_free (ssid, TRUE);
-	return active_ap;
-}
-
 static void
 update_seen_bssids_cache (NMDeviceWifi *self, NMAccessPoint *ap)
 {
@@ -537,11 +407,10 @@ set_current_ap (NMDeviceWifi *self, NMAccessPoint *new_ap, gboolean recheck_avai
 }
 
 static void
-periodic_update (NMDeviceWifi *self, NMAccessPoint *ignore_ap)
+periodic_update (NMDeviceWifi *self)
 {
 	NMDeviceWifiPrivate *priv = NM_DEVICE_WIFI_GET_PRIVATE (self);
 	int ifindex = nm_device_get_ifindex (NM_DEVICE (self));
-	NMAccessPoint *new_ap;
 	guint32 new_rate;
 	int percent;
 	NMDeviceState state;
@@ -568,65 +437,15 @@ periodic_update (NMDeviceWifi *self, NMAccessPoint *ignore_ap)
 	if (priv->mode == NM_802_11_MODE_AP)
 		return;
 
-	/* In IBSS mode, most newer firmware/drivers do "BSS coalescing" where
-	 * multiple IBSS stations using the same SSID will eventually switch to
-	 * using the same BSSID to avoid network segmentation.  When this happens,
-	 * the card's reported BSSID will change, but the new BSS may not
-	 * be in the scan list, since scanning isn't done in ad-hoc mode for
-	 * various reasons.  So pull the BSSID from the card and update the
-	 * current AP with it, if the current AP is adhoc.
-	 */
-	if (priv->current_ap && (nm_ap_get_mode (priv->current_ap) == NM_802_11_MODE_ADHOC)) {
-		guint8 bssid[ETH_ALEN] = { 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 };
-
-		nm_platform_wifi_get_bssid (ifindex, bssid);
-		/* 0x02 means "locally administered" and should be OR-ed into
-		 * the first byte of IBSS BSSIDs.
-		 */
-		if ((bssid[0] & 0x02) && nm_ethernet_address_is_valid (bssid, ETH_ALEN)) {
-			char *bssid_str = nm_utils_hwaddr_ntoa (bssid, ETH_ALEN);
-			nm_ap_set_address (priv->current_ap, bssid_str);
-			g_free (bssid_str);
-		}
-	}
-
-	new_ap = find_active_ap (self, ignore_ap, FALSE);
-	if (new_ap) {
-		/* Try to smooth out the strength.  Atmel cards, for example, will give no strength
-		 * one second and normal strength the next.
-		 */
+	if (priv->current_ap) {
+		/* Smooth out the strength to work around crappy drivers */
 		percent = nm_platform_wifi_get_quality (ifindex);
 		if (percent >= 0 || ++priv->invalid_strength_counter > 3) {
-			nm_ap_set_strength (new_ap, (gint8) percent);
+			nm_ap_set_strength (priv->current_ap, (gint8) percent);
 			priv->invalid_strength_counter = 0;
 		}
 	}
 
-	if (new_ap != priv->current_ap) {
-		const char *new_bssid = NULL;
-		const GByteArray *new_ssid = NULL;
-		const char *old_bssid = NULL;
-		const GByteArray *old_ssid = NULL;
-
-		if (new_ap) {
-			new_bssid = nm_ap_get_address (new_ap);
-			new_ssid = nm_ap_get_ssid (new_ap);
-		}
-
-		if (priv->current_ap) {
-			old_bssid = nm_ap_get_address (priv->current_ap);
-			old_ssid = nm_ap_get_ssid (priv->current_ap);
-		}
-
-		_LOGI (LOGD_WIFI, "roamed from BSSID %s (%s) to %s (%s)",
-		       old_bssid ? old_bssid : "(none)",
-		       old_ssid ? nm_utils_escape_ssid (old_ssid->data, old_ssid->len) : "(none)",
-		       new_bssid ? new_bssid : "(none)",
-		       new_ssid ? nm_utils_escape_ssid (new_ssid->data, new_ssid->len) : "(none)");
-
-		set_current_ap (self, new_ap, TRUE, FALSE);
-	}
-
 	new_rate = nm_platform_wifi_get_rate (ifindex);
 	if (new_rate != priv->rate) {
 		priv->rate = new_rate;
@@ -637,7 +456,7 @@ periodic_update (NMDeviceWifi *self, NMAccessPoint *ignore_ap)
 static gboolean
 periodic_update_cb (gpointer user_data)
 {
-	periodic_update (NM_DEVICE_WIFI (user_data), NULL);
+	periodic_update (NM_DEVICE_WIFI (user_data));
 	return TRUE;
 }
 
@@ -1834,6 +1653,7 @@ supplicant_iface_new_bss_cb (NMSupplicantInterface *iface,
                              GVariant *properties,
                              NMDeviceWifi *self)
 {
+	NMDeviceWifiPrivate *priv = NM_DEVICE_WIFI_GET_PRIVATE (self);
 	NMDeviceState state;
 	NMAccessPoint *ap;
 
@@ -1855,6 +1675,12 @@ supplicant_iface_new_bss_cb (NMSupplicantInterface *iface,
 		/* Add the AP to the device's AP list */
 		merge_scanned_ap (self, ap);
 		g_object_unref (ap);
+
+		/* Update the current AP if the supplicant notified a current BSS change
+		 * before it sent the current BSS's scan result.
+		 */
+		if (g_strcmp0 (nm_supplicant_interface_get_current_bss (iface), object_path) == 0)
+			supplicant_iface_notify_current_bss (priv->sup_iface, NULL, self);
 	} else
 		_LOGW (LOGD_WIFI_SCAN, "invalid AP properties received");
 
@@ -2215,7 +2041,7 @@ supplicant_iface_state_cb (NMSupplicantInterface *iface,
 			                                    g_bytes_get_size (ssid)) : "(none)");
 			nm_device_activate_schedule_stage3_ip_config_start (device);
 		} else if (devstate == NM_DEVICE_STATE_ACTIVATED)
-			periodic_update (self, NULL);
+			periodic_update (self);
 		break;
 	case NM_SUPPLICANT_INTERFACE_STATE_DISCONNECTED:
 		if ((devstate == NM_DEVICE_STATE_ACTIVATED) || nm_device_is_activating (device)) {
@@ -2315,7 +2141,53 @@ supplicant_iface_notify_scanning_cb (NMSupplicantInterface *iface,
 	/* Run a quick update of current AP when coming out of a scan */
 	state = nm_device_get_state (NM_DEVICE (self));
 	if (!scanning && state == NM_DEVICE_STATE_ACTIVATED)
-		periodic_update (self, NULL);
+		periodic_update (self);
+}
+
+static void
+supplicant_iface_notify_current_bss (NMSupplicantInterface *iface,
+                                     GParamSpec *pspec,
+                                     NMDeviceWifi *self)
+{
+	NMDeviceWifiPrivate *priv = NM_DEVICE_WIFI_GET_PRIVATE (self);
+	const char *current_bss;
+	NMAccessPoint *new_ap = NULL;
+
+	current_bss = nm_supplicant_interface_get_current_bss (iface);
+	if (current_bss)
+		new_ap = get_ap_by_supplicant_path (self, current_bss);
+
+	if (new_ap != priv->current_ap) {
+		const char *new_bssid = NULL;
+		const GByteArray *new_ssid = NULL;
+		const char *old_bssid = NULL;
+		const GByteArray *old_ssid = NULL;
+
+		/* Don't ever replace a "fake" current AP if we don't know about the
+		 * supplicant's current BSS yet.  It'll get replaced when we receive
+		 * the current BSS's scan result.
+		 */
+		if (new_ap == NULL && nm_ap_get_fake (priv->current_ap))
+			return;
+
+		if (new_ap) {
+			new_bssid = nm_ap_get_address (new_ap);
+			new_ssid = nm_ap_get_ssid (new_ap);
+		}
+
+		if (priv->current_ap) {
+			old_bssid = nm_ap_get_address (priv->current_ap);
+			old_ssid = nm_ap_get_ssid (priv->current_ap);
+		}
+
+		_LOGD (LOGD_WIFI, "roamed from BSSID %s (%s) to %s (%s)",
+		       old_bssid ? old_bssid : "(none)",
+		       old_ssid ? nm_utils_escape_ssid (old_ssid->data, old_ssid->len) : "(none)",
+		       new_bssid ? new_bssid : "(none)",
+		       new_ssid ? nm_utils_escape_ssid (new_ssid->data, new_ssid->len) : "(none)");
+
+		set_current_ap (self, new_ap, TRUE, FALSE);
+	}
 }
 
 static NMActStageReturn
@@ -2979,9 +2851,6 @@ activation_success_handler (NMDevice *device)
 	NMDeviceWifi *self = NM_DEVICE_WIFI (device);
 	NMDeviceWifiPrivate *priv = NM_DEVICE_WIFI_GET_PRIVATE (self);
 	int ifindex = nm_device_get_ifindex (device);
-	NMAccessPoint *ap;
-	guint8 bssid[ETH_ALEN] = { 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 };
-	NMAccessPoint *tmp_ap = NULL;
 	NMActRequest *req;
 	NMConnection *connection;
 
@@ -2997,62 +2866,38 @@ activation_success_handler (NMDevice *device)
 	/* Clear wireless secrets tries on success */
 	g_object_set_data (G_OBJECT (connection), WIRELESS_SECRETS_TRIES, NULL);
 
-	ap = priv->current_ap;
-
-	/* If the AP isn't fake, it was found in the scan list and all its
-	 * details are known.
-	 */
-	if (!ap || !nm_ap_get_fake (ap)){
-		ap = NULL;
-		goto done;
-	}
-
-	/* If the activate AP was fake, it probably won't have a BSSID at all.
-	 * But if activation was successful, the card will know the BSSID.  Grab
-	 * the BSSID off the card and fill in the BSSID of the activation AP.
+	/* There should always be a current AP, either a fake one because we haven't
+	 * seen a scan result for the activated AP yet, or a real one from the
+	 * supplicant's scan list.
 	 */
-	nm_platform_wifi_get_bssid (ifindex, bssid);
-	if (!nm_ap_get_address (ap)) {
-		char *bssid_str = nm_utils_hwaddr_ntoa (bssid, ETH_ALEN);
-		nm_ap_set_address (ap, bssid_str);
-		g_free (bssid_str);
-	}
-	if (!nm_ap_get_freq (ap))
-		nm_ap_set_freq (ap, nm_platform_wifi_get_frequency (ifindex));
-	if (!nm_ap_get_max_bitrate (ap))
-		nm_ap_set_max_bitrate (ap, nm_platform_wifi_get_rate (ifindex));
-
-	tmp_ap = find_active_ap (self, ap, TRUE);
-	if (tmp_ap) {
-		const GByteArray *ssid = nm_ap_get_ssid (tmp_ap);
-
-		/* Found a better match in the scan list than the fake AP.  Use it
-		 * instead.
-		 */
-
-		/* If the better match was a hidden AP, update its SSID */
-		if (!ssid || nm_utils_is_empty_ssid (ssid->data, ssid->len)) {
-			ssid = nm_ap_get_ssid (ap);
-			nm_ap_set_ssid (tmp_ap, ssid->data, ssid->len);
+	g_warn_if_fail (priv->current_ap);
+	if (priv->current_ap) {
+		if (nm_ap_get_fake (priv->current_ap)) {
+			/* If the activation AP hasn't been seen by the supplicant in a scan
+			 * yet, it will be "fake".  This usually happens for Ad-Hoc and
+			 * AP-mode connections.  Fill in the details from the device itself
+			 * until the supplicant sends the scan result.
+			 */
+			if (!nm_ap_get_address (priv->current_ap)) {
+				guint8 bssid[ETH_ALEN] = { 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 };
+				gs_free char *bssid_str = NULL;
+
+				if (   nm_platform_wifi_get_bssid (ifindex, bssid)
+				    && nm_ethernet_address_is_valid (bssid, ETH_ALEN)) {
+					bssid_str = nm_utils_hwaddr_ntoa (bssid, ETH_ALEN);
+					nm_ap_set_address (priv->current_ap, bssid_str);
+				}
+			}
+			if (!nm_ap_get_freq (priv->current_ap))
+				nm_ap_set_freq (priv->current_ap, nm_platform_wifi_get_frequency (ifindex));
+			if (!nm_ap_get_max_bitrate (priv->current_ap))
+				nm_ap_set_max_bitrate (priv->current_ap, nm_platform_wifi_get_rate (ifindex));
 		}
 
-		nm_active_connection_set_specific_object (NM_ACTIVE_CONNECTION (req),
-		                                          nm_ap_get_dbus_path (tmp_ap));
-	}
-
-done:
-	periodic_update (self, ap);
-
-	/* ap might be already unrefed, because it was a fake_ap. But we don't touch it... */
-	if (tmp_ap && ap == priv->current_ap) {
-		/* Strange, we would expect periodic_update() to find a better AP
-		 * then the fake one and reset it. Reset the fake current_ap to NULL
-		 * now, which will remove the fake ap.
-		 **/
-		set_current_ap (self, NULL, TRUE, FALSE);
+		nm_active_connection_set_specific_object (NM_ACTIVE_CONNECTION (req), nm_ap_get_dbus_path (priv->current_ap));
 	}
 
-	/* No need to update seen BSSIDs cache, that is done by set_current_ap() already */
+	periodic_update (self);
 
 	/* Reset scan interval to something reasonable */
 	priv->scan_interval = SCAN_INTERVAL_MIN + (SCAN_INTERVAL_STEP * 2);