Bluetooth: Add framework for device found filtering based on UUID

Using Start Service Discovery provides the option to specifiy a list
of UUID that are used to filter out device found events. This patch
provides the framework for hooking up the UUID filter.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

1 files changed, 52 insertions, 2 deletions

diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 1715c91dfa28..e39190a51590 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -6802,6 +6802,11 @@ void mgmt_read_local_oob_data_complete(struct hci_dev *hdev, u8 *hash192,
         mgmt_pending_remove(cmd);
 }
 
+static bool eir_has_uuids(u8 *eir, u16 eir_len, u16 uuid_count, u8 (*uuids)[16])
+{
+        return false;
+}
+
 void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
                        u8 addr_type, u8 *dev_class, s8 rssi, u32 flags,
                        u8 *eir, u16 eir_len, u8 *scan_rsp, u8 scan_rsp_len)
@@ -6809,6 +6814,7 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
         char buf[512];
         struct mgmt_ev_device_found *ev = (void *) buf;
         size_t ev_size;
+        bool match;
 
         /* Don't send events for a non-kernel initiated discovery. With
          * LE one exception is if we have pend_le_reports > 0 in which
@@ -6843,15 +6849,59 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
         ev->rssi = rssi;
         ev->flags = cpu_to_le32(flags);
 
-        if (eir_len > 0)
+        if (eir_len > 0) {
+                /* When using service discovery and a list of UUID is
+                 * provided, results with no matching UUID should be
+                 * dropped. In case there is a match the result is
+                 * kept and checking possible scan response data
+                 * will be skipped.
+                 */
+                if (hdev->discovery.uuid_count > 0) {
+                        match = eir_has_uuids(eir, eir_len,
+                                              hdev->discovery.uuid_count,
+                                              hdev->discovery.uuids);
+                        if (!match)
+                                return;
+                }
+
+                /* Copy EIR or advertising data into event */
                 memcpy(ev->eir, eir, eir_len);
+        } else {
+                /* When using service discovery and a list of UUID is
+                 * provided, results with empty EIR or advertising data
+                 * should be dropped since they do not match any UUID.
+                 */
+                if (hdev->discovery.uuid_count > 0)
+                        return;
+        }
 
         if (dev_class && !eir_has_data_type(ev->eir, eir_len, EIR_CLASS_OF_DEV))
                 eir_len = eir_append_data(ev->eir, eir_len, EIR_CLASS_OF_DEV,
                                           dev_class, 3);
 
-        if (scan_rsp_len > 0)
+        if (scan_rsp_len > 0) {
+                /* When using service discovery and a list of UUID is
+                 * provided, results with no matching UUID should be
+                 * dropped if there is no previous match from the
+                 * advertising data.
+                 */
+                if (hdev->discovery.uuid_count > 0) {
+                        if (!match && !eir_has_uuids(scan_rsp, scan_rsp_len,
+                                                     hdev->discovery.uuid_count,
+                                                     hdev->discovery.uuids))
+                                return;
+                }
+
+                /* Append scan response data to event */
                 memcpy(ev->eir + eir_len, scan_rsp, scan_rsp_len);
+        } else {
+                /* When using service discovery and a list of UUID is
+                 * provided, results with empty scan response and no
+                 * previous matched advertising data should be dropped.
+                 */
+                if (hdev->discovery.uuid_count > 0 && !match)
+                        return;
+        }
 
         ev->eir_len = cpu_to_le16(eir_len + scan_rsp_len);
         ev_size = sizeof(*ev) + eir_len + scan_rsp_len;