wifi: libertas: add support for WPS enrollee IE in probe requests

Add compatibility with WPS by passing on WPS enrollee information in
probe requests. Ignore other IEs supplied in the scan request. This also
has the added benefit of restoring compatibility with newer
wpa_supplicant versions that always add scan IEs. Previously, with
max_scan_ie_len set to 0, scans would always fail.
Suggested-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: Doug Brown <doug@schmorgal.com>
Reviewed-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230123053132.30710-5-doug@schmorgal.com

drivers/net/wireless/marvell/libertas/cfg.c

@@ -446,6 +446,41 @@ static int lbs_add_wpa_tlv(u8 *tlv, const u8 *ie, u8 ie_len)
 	return sizeof(struct mrvl_ie_header) + wpaie->datalen;
 }
 
+/* Add WPS enrollee TLV
+ */
+#define LBS_MAX_WPS_ENROLLEE_TLV_SIZE		\
+	(sizeof(struct mrvl_ie_header)		\
+	 + 256)
+
+static int lbs_add_wps_enrollee_tlv(u8 *tlv, const u8 *ie, size_t ie_len)
+{
+	struct mrvl_ie_data *wpstlv = (struct mrvl_ie_data *)tlv;
+	const struct element *wpsie;
+
+	/* Look for a WPS IE and add it to the probe request */
+	wpsie = cfg80211_find_vendor_elem(WLAN_OUI_MICROSOFT,
+					  WLAN_OUI_TYPE_MICROSOFT_WPS,
+					  ie, ie_len);
+	if (!wpsie)
+		return 0;
+
+	/* Convert the WPS IE to a TLV. The IE looks like this:
+	 *   u8      type (WLAN_EID_VENDOR_SPECIFIC)
+	 *   u8      len
+	 *   u8[]    data
+	 * but the TLV will look like this instead:
+	 *   __le16  type (TLV_TYPE_WPS_ENROLLEE)
+	 *   __le16  len
+	 *   u8[]    data
+	 */
+	wpstlv->header.type = cpu_to_le16(TLV_TYPE_WPS_ENROLLEE);
+	wpstlv->header.len = cpu_to_le16(wpsie->datalen);
+	memcpy(wpstlv->data, wpsie->data, wpsie->datalen);
+
+	/* Return the total number of bytes added to the TLV buffer */
+	return sizeof(struct mrvl_ie_header) + wpsie->datalen;
+}
+
 /*
  * Set Channel
  */
@@ -672,14 +707,15 @@ static int lbs_ret_scan(struct lbs_private *priv, unsigned long dummy,
 
 
 /*
- * Our scan command contains a TLV, consting of a SSID TLV, a channel list
- * TLV and a rates TLV. Determine the maximum size of them:
+ * Our scan command contains a TLV, consisting of a SSID TLV, a channel list
+ * TLV, a rates TLV, and an optional WPS IE. Determine the maximum size of them:
  */
 #define LBS_SCAN_MAX_CMD_SIZE			\
 	(sizeof(struct cmd_ds_802_11_scan)	\
 	 + LBS_MAX_SSID_TLV_SIZE		\
 	 + LBS_MAX_CHANNEL_LIST_TLV_SIZE	\
-	 + LBS_MAX_RATES_TLV_SIZE)
+	 + LBS_MAX_RATES_TLV_SIZE		\
+	 + LBS_MAX_WPS_ENROLLEE_TLV_SIZE)
 
 /*
  * Assumes priv->scan_req is initialized and valid
@@ -728,6 +764,11 @@ static void lbs_scan_worker(struct work_struct *work)
 	/* add rates TLV */
 	tlv += lbs_add_supported_rates_tlv(tlv);
 
+	/* add optional WPS enrollee TLV */
+	if (priv->scan_req->ie && priv->scan_req->ie_len)
+		tlv += lbs_add_wps_enrollee_tlv(tlv, priv->scan_req->ie,
+						priv->scan_req->ie_len);
+
 	if (priv->scan_channel < priv->scan_req->n_channels) {
 		cancel_delayed_work(&priv->scan_work);
 		if (netif_running(priv->dev))
@@ -2114,6 +2155,7 @@ int lbs_cfg_register(struct lbs_private *priv)
 	int ret;
 
 	wdev->wiphy->max_scan_ssids = 1;
+	wdev->wiphy->max_scan_ie_len = 256;
 	wdev->wiphy->signal_type = CFG80211_SIGNAL_TYPE_MBM;
 
 	wdev->wiphy->interface_modes =