Bluetooth: Refactor service discovery filter logic

This patch refactor code responsible for filtering when service
discovery method is used. Previously this code was mixed with
mgmt_device found logic. Now when it's in one place whole logic can
be greatly simplified. That includes removing no longer necessary
length field and merging checks for eir and scan_rsp.

Signed-off-by: Jakub Pawlowski <jpawlowski@google.com>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index a41a5ef..bc09c5a 100644 (file)
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -7283,8 +7283,6 @@ static void restart_le_scan(struct hci_dev *hdev)
 static bool is_filter_match(struct hci_dev *hdev, s8 rssi, u8 *eir,
                            u16 eir_len, u8 *scan_rsp, u8 scan_rsp_len)
 {
-       bool match;
-
        /* If a RSSI threshold has been specified, and
         * HCI_QUIRK_STRICT_DUPLICATE_FILTER is not set, then all results with
         * a RSSI smaller than the RSSI threshold will be dropped. If the quirk
@@ -7300,78 +7298,29 @@ static bool is_filter_match(struct hci_dev *hdev, s8 rssi, u8 *eir,
             !test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER, &hdev->quirks))))
                return  false;
 
-
-       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 duplicate filtering does not report RSSI changes,
-                        * then restart scanning to ensure updated result with
-                        * updated RSSI values.
-                        */
-                       if (match && test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER,
-                                             &hdev->quirks))
-                               restart_le_scan(hdev);
-               } else {
-                       match = true;
-               }
-
-               if (!match && !scan_rsp_len)
-                       return  false;
-       } 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 && !scan_rsp_len)
-                       return  false;
-
-               match = false;
-       }
-
-       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  false;
-
-                       /* If duplicate filtering does not report RSSI changes,
-                        * then restart scanning to ensure updated result with
-                        * updated RSSI values.
-                        */
-                       if (test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER,
-                                    &hdev->quirks))
-                               restart_le_scan(hdev);
-               }
-       } 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) {
+               /* If a list of UUIDs is provided in filter, results with no
+                * matching UUID should be dropped.
                 */
-               if (hdev->discovery.uuid_count > 0 && !match)
-                       return  false;
+               if (!eir_has_uuids(eir, eir_len, hdev->discovery.uuid_count,
+                                  hdev->discovery.uuids) &&
+                   !eir_has_uuids(scan_rsp, scan_rsp_len,
+                                  hdev->discovery.uuid_count,
+                                  hdev->discovery.uuids))
+                       return false;
        }
 
-       /* Validate the reported RSSI value against the RSSI threshold once more
-        * incase HCI_QUIRK_STRICT_DUPLICATE_FILTER forced a restart of LE
-        * scanning.
+       /* If duplicate filtering does not report RSSI changes, then restart
+        * scanning to ensure updated result with updated RSSI values.
         */
-       if (hdev->discovery.rssi != HCI_RSSI_INVALID &&
-           rssi < hdev->discovery.rssi)
-               return  false;
+       if (test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER, &hdev->quirks)) {
+               restart_le_scan(hdev);
+
+               /* Validate RSSI value against the RSSI threshold once more. */
+               if (hdev->discovery.rssi != HCI_RSSI_INVALID &&
+                   rssi < hdev->discovery.rssi)
+                       return false;
+       }
 
        return true;
 }