Bluetooth: Mesh: add API to set chunk send interval

This commit adds a KConfig option and an API to set the interval in
which chunks get send, in milliseconds.

Signed-off-by: Kyra Lengfeld <[email protected]>

Author: KyraLengfeld

include/zephyr/bluetooth/mesh/blob_cli.h

@@ -282,6 +282,10 @@ struct blob_cli_broadcast_ctx {
 	 *  and broadcast_complete calls.
 	 */
 	bool is_inited;
+	/* Defines a time in ms by which the broadcast API postpones sending the message to a next
+	 * target or completing the broadcast.
+	 */
+	uint32_t post_send_delay_ms;
 };
 /** INTERNAL_HIDDEN @endcond */
 
@@ -299,7 +303,7 @@ struct bt_mesh_blob_cli {
 		struct k_work_delayable retry;
 		/* Represents Client Timeout timer in a timestamp. Used in Pull mode only. */
 		int64_t cli_timestamp;
-		struct k_work complete;
+		struct k_work_delayable complete;
 		uint16_t pending;
 		uint8_t retries;
 		uint8_t sending : 1,
@@ -309,6 +313,7 @@ struct bt_mesh_blob_cli {
 	const struct bt_mesh_blob_io *io;
 	const struct bt_mesh_blob_cli_inputs *inputs;
 	const struct bt_mesh_blob_xfer *xfer;
+	uint32_t chunk_interval_ms;
 	uint16_t block_count;
 	uint16_t chunk_idx;
 	uint16_t mtu_size;
@@ -419,6 +424,22 @@ uint8_t bt_mesh_blob_cli_xfer_progress_active_get(struct bt_mesh_blob_cli *cli);
  */
 bool bt_mesh_blob_cli_is_busy(struct bt_mesh_blob_cli *cli);
 
+/** @brief Set chunk sending interval in ms
+ *
+ *  This function is optional, and can be used to define how fast chunks are sent in the BLOB Client
+ *  Model.
+ *  Without an added delay, for example a Bluetooth Mesh DFU can cause network blockage by
+ *  constantly sending the next chunks, especially if the chunks are sent to group addresses or
+ *  multiple unicast addresses.
+ *
+ *  @note: Big intervals may cause timeouts. Increasing the @c timeout_base accordingly can
+ *  circumvent this.
+ *
+ *  @param cli BLOB Transfer Client instance.
+ *  @param interval_ms the delay before each chunk is sent out in ms.
+ */
+void bt_mesh_blob_cli_set_chunk_interval_ms(struct bt_mesh_blob_cli *cli, uint32_t interval_ms);
+
 /** @cond INTERNAL_HIDDEN */
 extern const struct bt_mesh_model_op _bt_mesh_blob_cli_op[];
 extern const struct bt_mesh_model_cb _bt_mesh_blob_cli_cb;

subsys/bluetooth/mesh/Kconfig

@@ -935,6 +935,18 @@ config BT_MESH_TX_BLOB_CHUNK_SIZE
 	  see also: BT_MESH_TX_SEG_MAX,
 	  and the maximum SDU a node can receive.
 
+config BT_MESH_TX_BLOB_CHUNK_SEND_INTERVAL
+	int "BLOB Client chunk send interval"
+	default 0
+	range 0 2147483647
+	help
+	  Set the interval in milliseconds in which chunks are sent during the BLOB transfer.
+	  Note: Without a delay between each sent chunk, the network might become too busy with the
+	  BLOB transfer for other communications to succeed.
+	  Note: Timing restrictions, like the timeout base, should be considered or changed
+	  accordingly when setting this interval. Otherwise, the interval might be too big for the
+	  timeout settings and cause timeouts.
+
 endif # BT_MESH_BLOB_CLI
 
 menu "BLOB models common configuration"

subsys/bluetooth/mesh/blob_cli.c

@@ -407,8 +407,8 @@ static void broadcast_complete(struct bt_mesh_blob_cli *cli)
 
 static void tx_complete(struct k_work *work)
 {
-	struct bt_mesh_blob_cli *cli =
-		CONTAINER_OF(work, struct bt_mesh_blob_cli, tx.complete);
+	struct k_work_delayable *dwork = k_work_delayable_from_work(work);
+	struct bt_mesh_blob_cli *cli = CONTAINER_OF(dwork, struct bt_mesh_blob_cli, tx.complete);
 
 	if (!cli->tx.ctx.is_inited || !cli->tx.sending) {
 		return;
@@ -540,7 +540,7 @@ void blob_cli_broadcast(struct bt_mesh_blob_cli *cli,
 
 void blob_cli_broadcast_tx_complete(struct bt_mesh_blob_cli *cli)
 {
-	k_work_submit(&cli->tx.complete);
+	k_work_schedule(&cli->tx.complete, K_MSEC(cli->tx.ctx.post_send_delay_ms));
 }
 
 void blob_cli_broadcast_rsp(struct bt_mesh_blob_cli *cli,
@@ -932,6 +932,7 @@ static void chunk_send(struct bt_mesh_blob_cli *cli)
 		.send = chunk_tx,
 		.next = chunk_send_end,
 		.acked = false,
+		.post_send_delay_ms = cli->chunk_interval_ms,
 	};
 
 	if (cli->xfer->mode == BT_MESH_BLOB_XFER_MODE_PULL) {
@@ -1462,9 +1463,10 @@ static int blob_cli_init(const struct bt_mesh_model *mod)
 
 	cli->mod = mod;
 
+	bt_mesh_blob_cli_set_chunk_interval_ms(cli, CONFIG_BT_MESH_TX_BLOB_CHUNK_SEND_INTERVAL);
 	cli->tx.cli_timestamp = 0ll;
 	k_work_init_delayable(&cli->tx.retry, retry_timeout);
-	k_work_init(&cli->tx.complete, tx_complete);
+	k_work_init_delayable(&cli->tx.complete, tx_complete);
 
 	return 0;
 }
@@ -1649,3 +1651,8 @@ bool bt_mesh_blob_cli_is_busy(struct bt_mesh_blob_cli *cli)
 {
 	return cli->state != BT_MESH_BLOB_CLI_STATE_NONE;
 }
+
+void bt_mesh_blob_cli_set_chunk_interval_ms(struct bt_mesh_blob_cli *cli, uint32_t interval_ms)
+{
+	cli->chunk_interval_ms = interval_ms;
+}