This patch fixes service discovery behaviour, when provided uuid filter
is empty and HCI_QUIRK_STRICT_DUPLICATE_FILTER is set. Before this
patch, empty uuid filter was unable to trigger scan restart, and that
caused inconsistent behaviour in applications.
Example: two DBus clients call BlueZ, one to find all devices with
service abcd, second to find all devices with rssi smaller than -90.
Sum of those filters, that is passed to mgmt_service_scan is empty
filter, with no rssi or uuids set.
That caused kernel not to restart scan when quirk was set.
That was inconsistent with what happen when there's only one of those
two filters set (scan is restarted and reports devices).
To fix that, new variable hdev->discovery.service_discovery was
introduced. It can indicate that filtered scan is running, no matter
what uuid or rssi filter is set.
This patch also closes all code responsible for filtered discovery in
one if statement. That makes whole code shorter, much more readable,
and easier to backport to older kernels, especially pre 3.10.
Signed-off-by: Jakub Pawlowski <jpawlowski@xxxxxxxxxx>
---
include/net/bluetooth/hci_core.h | 2 +
net/bluetooth/mgmt.c | 140 +++++++++++++++------------------------
2 files changed, 55 insertions(+), 87 deletions(-)
diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 52863c3..0b9315f 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -76,6 +76,7 @@ struct discovery_state {
u8 last_adv_data[HCI_MAX_AD_LENGTH];
u8 last_adv_data_len;
bool report_invalid_rssi;
+ bool service_discovery;
s8 rssi;
u16 uuid_count;
u8 (*uuids)[16];
@@ -529,6 +530,7 @@ static inline void discovery_init(struct hci_dev *hdev)
static inline void hci_discovery_filter_clear(struct hci_dev *hdev)
{
+ hdev->discovery.service_discovery = false;
hdev->discovery.report_invalid_rssi = true;
hdev->discovery.rssi = HCI_RSSI_INVALID;
hdev->discovery.uuid_count = 0;
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 1b528de..f3b2da6 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -3927,8 +3927,7 @@ static void start_discovery_complete(struct hci_dev *hdev, u8 status,
*/
if (test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER,
&hdev->quirks) &&
- (hdev->discovery.uuid_count > 0 ||
- hdev->discovery.rssi != HCI_RSSI_INVALID)) {
+ hdev->discovery.service_discovery) {
hdev->discovery.scan_start = jiffies;
hdev->discovery.scan_duration = timeout;
}
@@ -4081,6 +4080,7 @@ static int start_service_discovery(struct sock *sk, struct hci_dev *hdev,
*/
hci_discovery_filter_clear(hdev);
+ hdev->discovery.service_scan = true;
hdev->discovery.type = cp->type;
hdev->discovery.rssi = cp->rssi;
hdev->discovery.uuid_count = uuid_count;
@@ -7294,21 +7294,57 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
return;
}
- /* When using service discovery with a RSSI threshold, then check
- * if such a RSSI threshold is specified. 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 is set, let it through for further processing,
- * as we might need to restart the scan.
- *
- * For BR/EDR devices (pre 1.2) providing no RSSI during inquiry,
- * the results are also dropped.
- */
- if (hdev->discovery.rssi != HCI_RSSI_INVALID &&
- (rssi == HCI_RSSI_INVALID ||
- (rssi < hdev->discovery.rssi &&
- !test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER, &hdev->quirks))))
- return;
+ if (hdev->discovery.service_discovery) {
+ /* We are using service discovery */
+
+ /* 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 is set, let it through for further
+ * processing, as we might need to restart the scan.
+ *
+ * For BR/EDR devices (pre 1.2) providing no RSSI during
+ * inquiry, the results are also dropped.
+ */
+ if (hdev->discovery.rssi != HCI_RSSI_INVALID &&
+ (rssi == HCI_RSSI_INVALID ||
+ (rssi < hdev->discovery.rssi &&
+ !test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER,
+ &hdev->quirks))))
+ return;
+
+ /* If a list of UUID is provided, results with no matching UUID
+ * should be dropped. If list of UUID is not provided, treat
+ * all devices as matches.
+ * Empty UUID filter might be a result of merging filters
+ * somewhere in highter layer, and should behave same as when
+ * we have UUID match.
+ */
+ if (hdev->discovery.uuid_count != 0 &&
+ (eir_len == 0 || !eir_has_uuids(eir, eir_len,
+ hdev->discovery.uuid_count,
+ hdev->discovery.uuids)) &&
+ (scan_rsp_len == 0 || !eir_has_uuids(scan_rsp, scan_rsp_len,
+ hdev->discovery.uuid_count,
+ hdev->discovery.uuids)))
+ return;
+
+ /* 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);
+
+ /* Validate the reported RSSI value against the
+ * RSSI threshold once more.
+ */
+ if (hdev->discovery.rssi != HCI_RSSI_INVALID &&
+ rssi < hdev->discovery.rssi)
+ return;
+ }
+ }
/* Make sure that the buffer is big enough. The 5 extra bytes
* are for the potential CoD field.
@@ -7336,86 +7372,16 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
ev->flags = cpu_to_le32(flags);
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;
-
/* 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 && !scan_rsp_len)
- return;
-
- match = false;
- }
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) {
- /* 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;
-
- /* 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);
- }
-
/* 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;
- }
-
- /* Validate the reported RSSI value against the RSSI threshold once more
- * incase HCI_QUIRK_STRICT_DUPLICATE_FILTER forced a restart of LE
- * scanning.
- */
- if (hdev->discovery.rssi != HCI_RSSI_INVALID &&
- rssi < hdev->discovery.rssi)
- return;
ev->eir_len = cpu_to_le16(eir_len + scan_rsp_len);
ev_size = sizeof(*ev) + eir_len + scan_rsp_len;
--
2.2.0.rc0.207.ga3a616c
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