nrf_rpc: detect reboot of the remote

Raise an error when the remote sends an init packet with
unknown destination group ID after the group has been bound,
which indicates a reboot of the peer.

Signed-off-by: Damian Krolik <damian.krolik@nordicsemi.no>

nrf_rpc/include/nrf_rpc.h

@@ -66,6 +66,7 @@ enum nrf_rpc_err_src {
 	NRF_RPC_ERR_SRC_RECV,   /**< @brief Error during receiving */
 	NRF_RPC_ERR_SRC_SEND,   /**< @brief Error during sending */
 	NRF_RPC_ERR_SRC_REMOTE, /**< @brief Error reported be the remote */
+	NRF_RPC_ERR_SRC_REBOOT, /**< @brief Error due to reboot of the remote */
 };
 
 /* Helper nRF group structure declaration needed for callback definition. */

nrf_rpc/nrf_rpc.c

@@ -98,6 +98,7 @@ struct internal_task {
 			const struct nrf_rpc_group *group;
 			bool send_reply;
 			bool signal_groups_init_event;
+			bool signal_reboot;
 		} group_init;
 
 		struct {
@@ -379,6 +380,11 @@ static void internal_tx_handler(void)
 	case NRF_RPC_TASK_GROUP_INIT: {
 		const struct nrf_rpc_group *group = task.group_init.group;
 
+		if (task.group_init.signal_reboot) {
+			nrf_rpc_err(-NRF_ECONNRESET, NRF_RPC_ERR_SRC_REBOOT, group,
+				    NRF_RPC_ID_UNKNOWN, NRF_RPC_PACKET_TYPE_INIT);
+		}
+
 		if (task.group_init.send_reply && group_init_send(group)) {
 			NRF_RPC_ERR("Failed to send group init packet for group id: %d strid: %s",
 				    group->data->src_group_id, group->strid);
@@ -710,6 +716,7 @@ static int init_packet_handle(struct header *hdr, const struct nrf_rpc_group **g
 		internal_task.group_init.group = *group;
 		internal_task.group_init.send_reply = send_reply;
 		internal_task.group_init.signal_groups_init_event = signal_groups_init_event;
+		internal_task.group_init.signal_reboot = send_reply && !first_init;
 		nrf_rpc_os_thread_pool_send((const uint8_t *)&internal_task, sizeof(internal_task));
 		nrf_rpc_os_event_wait(&internal_task_consumed, NRF_RPC_OS_WAIT_FOREVER);
 	}