net: openthread: rpc: network interface changes

1. Enable implementation of RPC commands for sending and
   receiving IPv6 packets only if OPENTHREAD_RPC_NET_IF
   Kconfig option is set. This is to enable using OT RPC
   without the Zephyr networking stack.
2. Autostart OpenThread network interface on the RPC server
   even if the network interface is not present or enabled
   on the RPC client side. This is because when the
   interface is disabled on the server side, the received
   frames are not even delivered to the OpenThread stack.
3. Other minor cleanup.

Signed-off-by: Damian Krolik <[email protected]>

samples/nrf_rpc/protocols_serialization/server/snippets/openthread/openthread.conf

@@ -14,7 +14,6 @@ CONFIG_NET_SOCKETS=y
 CONFIG_NET_SOCKETS_PACKET=y
 CONFIG_OPENTHREAD_RPC=y
 CONFIG_OPENTHREAD_RPC_SERVER=y
-CONFIG_IEEE802154_NET_IF_NO_AUTO_START=y # Let RPC client start the interface on demand
 CONFIG_OPENTHREAD_MANUAL_START=y
 CONFIG_NET_BUF_RX_COUNT=80
 CONFIG_NET_BUF_TX_COUNT=80

subsys/net/openthread/rpc/Kconfig

@@ -24,7 +24,6 @@ choice OPENTHREAD_RPC_ROLE_CHOICE
 
 config OPENTHREAD_RPC_CLIENT
  bool "OpenThread over RPC client"
- depends on NETWORKING
  help
  Enables OpenThread over RPC client role that uses nRF RPC library to
  invoke OpenThread functions on the remote core.
@@ -39,6 +38,15 @@ config OPENTHREAD_RPC_SERVER
 
 endchoice
 
+config OPENTHREAD_RPC_NET_IF
+ bool "OpenThread over RPC network interface"
+ default y
+ depends on NETWORKING
+ help
+ Enables OpenThread RPC commands for sending and receiving IPv6 packets
+ to/from the OpenThread stack. For the RPC client role, it additionally
+ creates a Zephyr network interface that employs these commands.
+
 menu "OpenThread over RPC client configuration"
  depends on OPENTHREAD_RPC_CLIENT
 

subsys/net/openthread/rpc/client/CMakeLists.txt

@@ -11,7 +11,6 @@ zephyr_library_sources(
  ot_rpc_coap.c
  ot_rpc_diag.c
  ot_rpc_dataset.c
- ot_rpc_if.c
  ot_rpc_instance.c
  ot_rpc_ip6.c
  ot_rpc_link.c
@@ -22,6 +21,8 @@ zephyr_library_sources(
  ot_rpc_udp.c
 )
 
+zephyr_library_sources_ifdef(CONFIG_OPENTHREAD_RPC_NET_IF ot_rpc_if.c)
+
 zephyr_library_include_directories(
  ${CMAKE_CURRENT_SOURCE_DIR}/../common
 )

subsys/net/openthread/rpc/client/ot_rpc_if.c

@@ -159,26 +159,23 @@ static int ot_rpc_l2_enable(struct net_if *iface, bool state)
 {
  const size_t cbor_buffer_size = 1;
  struct nrf_rpc_cbor_ctx ctx;
- int error = 0;
-
- const otExtAddress *mac = otLinkGetExtendedAddress(0);
 
  if (!state) {
  otRemoveStateChangeCallback(NULL, ot_state_changed_handler, iface);
  }
 
- net_if_set_link_addr(iface, (uint8_t *)mac->m8, 8, NET_LINK_IEEE802154);
-
  NRF_RPC_CBOR_ALLOC(&ot_group, ctx, cbor_buffer_size);
  zcbor_bool_put(ctx.zs, state);
  nrf_rpc_cbor_cmd_no_err(&ot_group, OT_RPC_CMD_IF_ENABLE, &ctx, ot_rpc_decode_void, NULL);
 
  if (state) {
+ net_if_set_link_addr(iface, (uint8_t *)otLinkGetExtendedAddress(NULL)->m8,
+ OT_EXT_ADDRESS_SIZE, NET_LINK_IEEE802154);
  update_netif_addrs(iface);
  otSetStateChangedCallback(NULL, ot_state_changed_handler, iface);
  }
 
- return error;
+ return 0;
 }
 
 static enum net_l2_flags ot_rpc_l2_flags(struct net_if *iface)
@@ -195,7 +192,6 @@ static int ot_rpc_dev_init(const struct device *dev)
 
 static void ot_rpc_if_init(struct net_if *iface)
 {
- /* TODO: auto-start the interface when nRF RPC transport is ready? */
  net_if_flag_set(iface, NET_IF_NO_AUTO_START);
  net_if_flag_set(iface, NET_IF_IPV6_NO_ND);
  net_if_flag_set(iface, NET_IF_IPV6_NO_MLD);

subsys/net/openthread/rpc/server/CMakeLists.txt

@@ -19,11 +19,12 @@ zephyr_library_sources(
 )
 
 zephyr_library_sources_ifdef(CONFIG_NET_L2_OPENTHREAD
- ot_rpc_if.c
  ot_rpc_diag.c
  ot_rpc_udp.c
 )
 
+zephyr_library_sources_ifdef(CONFIG_OPENTHREAD_RPC_NET_IF ot_rpc_if.c)
+
 zephyr_library_include_directories(
  ${CMAKE_CURRENT_SOURCE_DIR}/../common
 )