This patch introduces the LE auto connection infrastructure.
This infrastructure will be used to implement the LE auto connection
options which will be introduced in a few patches ahead.
In summary, the auto connection mechanism works as follows: Once the
first pending LE connection is created, the background scanning is
started. When the target device is found in range, the kernel
autonomously starts the connection attempt. If connection is
established successfully, that pending LE connection is deleted and
the background is stopped.
To achieve that, this patch introduces the hci_update_background_scan()
which controls the background scanning state. This function starts or
stops the background scanning based on the hdev->pend_le_conns list. If
there is no pending LE connection, the background scanning is stopped.
Otherwise, we start the background scanning.
Then, every time a pending LE connection is added we call hci_update_
background_scan() so the background scanning is started (in case it is
not already running). Likewise, every time a pending LE connection is
deleted we call hci_update_background_scan() so the background scanning
is stopped (in case this was the last pending LE connection) or it is
started again (in case we have more pending LE connections). This way
the background scanning keeps running until all pending LE connection
are established.
When a device with pending connection is in range, we establish the
connection and delete the pending connection.
Signed-off-by: Andre Guedes <andre.guedes@xxxxxxxxxxxxx>
---
include/net/bluetooth/hci_core.h | 2 +
net/bluetooth/hci_core.c | 86 +++++++++++++++++++++++++++++++++++++++-
net/bluetooth/hci_event.c | 41 +++++++++++++++++++
3 files changed, 127 insertions(+), 2 deletions(-)
diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 97f758a..4591b8f 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -776,6 +776,8 @@ void hci_pend_le_conn_add(struct hci_dev *hdev, bdaddr_t *addr, u8 addr_type);
void hci_pend_le_conn_del(struct hci_dev *hdev, bdaddr_t *addr, u8 addr_type);
void hci_pend_le_conns_clear(struct hci_dev *hdev);
+void hci_update_background_scan(struct hci_dev *hdev);
+
int hci_uuids_clear(struct hci_dev *hdev);
int hci_link_keys_clear(struct hci_dev *hdev);
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index f353a71..388a453 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -3021,7 +3021,7 @@ void hci_pend_le_conn_add(struct hci_dev *hdev, bdaddr_t *addr, u8 addr_type)
entry = hci_pend_le_conn_lookup(hdev, addr, addr_type);
if (entry)
- return;
+ goto done;
entry = kzalloc(sizeof(*entry), GFP_KERNEL);
if (!entry) {
@@ -3035,6 +3035,9 @@ void hci_pend_le_conn_add(struct hci_dev *hdev, bdaddr_t *addr, u8 addr_type)
list_add(&entry->list, &hdev->pend_le_conns);
BT_DBG("addr %pMR (type %u)", addr, addr_type);
+
+done:
+ hci_update_background_scan(hdev);
}
/* This function requires the caller holds hdev->lock */
@@ -3044,12 +3047,15 @@ void hci_pend_le_conn_del(struct hci_dev *hdev, bdaddr_t *addr, u8 addr_type)
entry = hci_pend_le_conn_lookup(hdev, addr, addr_type);
if (!entry)
- return;
+ goto done;
list_del(&entry->list);
kfree(entry);
BT_DBG("addr %pMR (type %u)", addr, addr_type);
+
+done:
+ hci_update_background_scan(hdev);
}
/* This function requires the caller holds hdev->lock */
@@ -4591,3 +4597,79 @@ static void hci_cmd_work(struct work_struct *work)
}
}
}
+
+static void update_background_scan_complete(struct hci_dev *hdev, u8 status)
+{
+ if (status)
+ BT_DBG("HCI request failed to update background scanning: "
+ "status 0x%2.2x", status);
+}
+
+/* This function controls the background scanning based on hdev->pend_le_conns
+ * list. If there are pending LE connection we start the background scanning,
+ * otherwise we stop it.
+ *
+ * This function requires the caller holds hdev->lock.
+ */
+void hci_update_background_scan(struct hci_dev *hdev)
+{
+ struct hci_cp_le_set_scan_param param_cp;
+ struct hci_cp_le_set_scan_enable enable_cp;
+ struct hci_request req;
+ struct hci_conn *conn;
+ int err;
+
+ hci_req_init(&req, hdev);
+
+ if (list_empty(&hdev->pend_le_conns)) {
+ /* If there is no pending LE connections, we should stop
+ * the background scanning.
+ */
+
+ /* If controller is not scanning we are done. */
+ if (!test_bit(HCI_LE_SCAN, &hdev->dev_flags))
+ return;
+
+ memset(&enable_cp, 0, sizeof(enable_cp));
+ enable_cp.enable = LE_SCAN_DISABLE;
+ hci_req_add(&req, HCI_OP_LE_SET_SCAN_ENABLE, sizeof(enable_cp),
+ &enable_cp);
+
+ BT_DBG("%s stopping background scanning", hdev->name);
+ } else {
+ /* If there is at least one pending LE connection, we should
+ * keep the background scan running.
+ */
+
+ /* If controller is already scanning we are done. */
+ if (test_bit(HCI_LE_SCAN, &hdev->dev_flags))
+ return;
+
+ /* If controller is connecting, we should not start scanning
+ * since some controllers are not able to scan and connect at
+ * the same time.
+ */
+ conn = hci_conn_hash_lookup_state(hdev, LE_LINK, BT_CONNECT);
+ if (conn)
+ return;
+
+ memset(¶m_cp, 0, sizeof(param_cp));
+ param_cp.type = LE_SCAN_PASSIVE;
+ param_cp.interval = cpu_to_le16(hdev->le_scan_interval);
+ param_cp.window = cpu_to_le16(hdev->le_scan_window);
+ hci_req_add(&req, HCI_OP_LE_SET_SCAN_PARAM, sizeof(param_cp),
+ ¶m_cp);
+
+ memset(&enable_cp, 0, sizeof(enable_cp));
+ enable_cp.enable = LE_SCAN_ENABLE;
+ enable_cp.filter_dup = LE_SCAN_FILTER_DUP_DISABLE;
+ hci_req_add(&req, HCI_OP_LE_SET_SCAN_ENABLE, sizeof(enable_cp),
+ &enable_cp);
+
+ BT_DBG("%s starting background scanning", hdev->name);
+ }
+
+ err = hci_req_run(&req, update_background_scan_complete);
+ if (err)
+ BT_ERR("Failed to run HCI request: err %d", err);
+}
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index d2c6878..ef95030 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -3624,25 +3624,66 @@ static void hci_le_conn_complete_evt(struct hci_dev *hdev, struct sk_buff *skb)
hci_proto_connect_cfm(conn, ev->status);
+ hci_pend_le_conn_del(hdev, &ev->bdaddr, ev->bdaddr_type);
+
unlock:
hci_dev_unlock(hdev);
}
+/* This function requires the caller holds hdev->lock */
+static void check_pending_le_conn(struct hci_dev *hdev, bdaddr_t *addr,
+ u8 addr_type)
+{
+ struct hci_conn *conn;
+ u8 bdaddr_type;
+
+ if (!hci_pend_le_conn_lookup(hdev, addr, addr_type))
+ return;
+
+ if (addr_type == ADDR_LE_DEV_PUBLIC)
+ bdaddr_type = BDADDR_LE_PUBLIC;
+ else
+ bdaddr_type = BDADDR_LE_RANDOM;
+
+ conn = hci_connect(hdev, LE_LINK, addr, bdaddr_type, BT_SECURITY_LOW,
+ HCI_AT_NO_BONDING);
+ if (!IS_ERR(conn))
+ return;
+
+ switch (PTR_ERR(conn)) {
+ case -EBUSY:
+ /* If hci_connect() returns -EBUSY it means there is already
+ * an LE connection attempt going on. Since controllers don't
+ * support more than one connection attempt at the time, we
+ * don't consider this an error case.
+ */
+ break;
+ default:
+ BT_ERR("Failed to connect: err %ld", PTR_ERR(conn));
+ }
+}
+
static void hci_le_adv_report_evt(struct hci_dev *hdev, struct sk_buff *skb)
{
u8 num_reports = skb->data[0];
void *ptr = &skb->data[1];
s8 rssi;
+ hci_dev_lock(hdev);
+
while (num_reports--) {
struct hci_ev_le_advertising_info *ev = ptr;
+ check_pending_le_conn(hdev, &ev->bdaddr, ev->bdaddr_type);
+
rssi = ev->data[ev->length];
mgmt_device_found(hdev, &ev->bdaddr, LE_LINK, ev->bdaddr_type,
NULL, rssi, 0, 1, ev->data, ev->length);
ptr += sizeof(*ev) + ev->length + 1;
}
+
+ hci_dev_unlock(hdev);
}
static void hci_le_ltk_request_evt(struct hci_dev *hdev, struct sk_buff *skb)
--
1.8.5.3
--
To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
