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From: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
To: linux-bluetooth@vger.kernel.org
Subject: [RFC v5] Bluetooth: MGMT: Make MGMT_OP_LOAD_CONN_PARAM update existing connection
Date: Tue, 14 May 2024 13:51:49 -0400
Message-ID: <20240514175149.752522-1-luiz.dentz@gmail.com>
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From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This makes MGMT_OP_LOAD_CONN_PARAM update existing connection by
dectecting the request is just for one connection, parameters already
exists and there is a connection.

Since this is a new behavior the revision is also updated to enable
userspace to detect it.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
 include/net/bluetooth/hci_sync.h |  3 ++
 net/bluetooth/hci_sync.c         | 18 ++++++++++++
 net/bluetooth/mgmt.c             | 50 ++++++++++++++++++++++++++++++--
 3 files changed, 69 insertions(+), 2 deletions(-)

diff --git a/include/net/bluetooth/hci_sync.h b/include/net/bluetooth/hci_sync.h
index 6a9d063e9f47..b49057bbdf23 100644
--- a/include/net/bluetooth/hci_sync.h
+++ b/include/net/bluetooth/hci_sync.h
@@ -136,6 +136,7 @@ int hci_suspend_sync(struct hci_dev *hdev);
 int hci_resume_sync(struct hci_dev *hdev);
 
 struct hci_conn;
+struct hci_conn_params;
 
 int hci_abort_conn_sync(struct hci_dev *hdev, struct hci_conn *conn, u8 reason);
 
@@ -154,3 +155,5 @@ int hci_connect_acl_sync(struct hci_dev *hdev, struct hci_conn *conn);
 int hci_connect_le_sync(struct hci_dev *hdev, struct hci_conn *conn);
 
 int hci_cancel_connect_sync(struct hci_dev *hdev, struct hci_conn *conn);
+int hci_le_conn_update_sync(struct hci_dev *hdev, struct hci_conn *conn,
+			    struct hci_conn_params *params);
diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index 16daa79b7981..353de476a5cd 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -6711,3 +6711,21 @@ int hci_cancel_connect_sync(struct hci_dev *hdev, struct hci_conn *conn)
 
 	return -ENOENT;
 }
+
+int hci_le_conn_update_sync(struct hci_dev *hdev, struct hci_conn *conn,
+			    struct hci_conn_params *params)
+{
+	struct hci_cp_le_conn_update cp;
+
+	memset(&cp, 0, sizeof(cp));
+	cp.handle		= cpu_to_le16(conn->handle);
+	cp.conn_interval_min	= cpu_to_le16(params->conn_min_interval);
+	cp.conn_interval_max	= cpu_to_le16(params->conn_max_interval);
+	cp.conn_latency		= cpu_to_le16(params->conn_latency);
+	cp.supervision_timeout	= cpu_to_le16(params->supervision_timeout);
+	cp.min_ce_len		= cpu_to_le16(0x0000);
+	cp.max_ce_len		= cpu_to_le16(0x0000);
+
+	return __hci_cmd_sync_status(hdev, HCI_OP_LE_CONN_UPDATE,
+				     sizeof(cp), &cp, HCI_CMD_TIMEOUT);
+}
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 80f220b7e19d..20eca8a9c681 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -42,7 +42,7 @@
 #include "aosp.h"
 
 #define MGMT_VERSION	1
-#define MGMT_REVISION	22
+#define MGMT_REVISION	23
 
 static const u16 mgmt_commands[] = {
 	MGMT_OP_READ_INDEX_LIST,
@@ -7813,6 +7813,18 @@ static int remove_device(struct sock *sk, struct hci_dev *hdev,
 	return err;
 }
 
+static int conn_update_sync(struct hci_dev *hdev, void *data)
+{
+	struct hci_conn_params *params = data;
+	struct hci_conn *conn;
+
+	conn = hci_conn_hash_lookup_le(hdev, &params->addr, params->addr_type);
+	if (!conn)
+		return -ECANCELED;
+
+	return hci_le_conn_update_sync(hdev, conn, params);
+}
+
 static int load_conn_param(struct sock *sk, struct hci_dev *hdev, void *data,
 			   u16 len)
 {
@@ -7846,13 +7858,15 @@ static int load_conn_param(struct sock *sk, struct hci_dev *hdev, void *data,
 
 	hci_dev_lock(hdev);
 
-	hci_conn_params_clear_disabled(hdev);
+	if (param_count > 1)
+		hci_conn_params_clear_disabled(hdev);
 
 	for (i = 0; i < param_count; i++) {
 		struct mgmt_conn_param *param = &cp->params[i];
 		struct hci_conn_params *hci_param;
 		u16 min, max, latency, timeout;
 		u8 addr_type;
+		bool update;
 
 		bt_dev_dbg(hdev, "Adding %pMR (type %u)", &param->addr.bdaddr,
 			   param->addr.type);
@@ -7879,6 +7893,19 @@ static int load_conn_param(struct sock *sk, struct hci_dev *hdev, void *data,
 			continue;
 		}
 
+		/* Detect when the loading is for an existing parameter then
+		 * attempt to trigger the connection update procedure.
+		 */
+		if (!i && param_count == 1) {
+			hci_param = hci_conn_params_lookup(hdev,
+							   &param->addr.bdaddr,
+							   addr_type);
+			if (hci_param)
+				update = true;
+			else
+				hci_conn_params_clear_disabled(hdev);
+		}
+
 		hci_param = hci_conn_params_add(hdev, &param->addr.bdaddr,
 						addr_type);
 		if (!hci_param) {
@@ -7890,6 +7917,25 @@ static int load_conn_param(struct sock *sk, struct hci_dev *hdev, void *data,
 		hci_param->conn_max_interval = max;
 		hci_param->conn_latency = latency;
 		hci_param->supervision_timeout = timeout;
+
+		/* Check if we need to trigger a connection update */
+		if (update) {
+			struct hci_conn *conn;
+
+			/* Lookup for existing connection as central and check
+			 * if parameters match and if they don't then trigger
+			 * a connection update.
+			 */
+			conn = hci_conn_hash_lookup_le(hdev, &hci_param->addr,
+						       addr_type);
+			if (conn && conn->role == HCI_ROLE_MASTER &&
+			    (conn->le_conn_min_interval != min ||
+			     conn->le_conn_max_interval != max ||
+			     conn->le_conn_latency != latency ||
+			     conn->le_supv_timeout != timeout))
+				hci_cmd_sync_queue(hdev, conn_update_sync,
+						   hci_param, NULL);
+		}
 	}
 
 	hci_dev_unlock(hdev);
-- 
2.45.0