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>

1 files changed, 19 insertions, 70 deletions

diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index a41a5efa4391..bc09c5a37032 100644
--- 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;
 }