1a012b7ad2
added migration guide link to the esp-netif page and network page added redirects from tcpip_adapter to new esp_netif
149 lines
7 KiB
ReStructuredText
149 lines
7 KiB
ReStructuredText
ESP-NETIF
|
|
=========
|
|
|
|
The purpose of ESP-NETIF library is twofold:
|
|
|
|
- It provides an abstraction layer for the application on top of the TCP/IP stack. This will allow applications to choose between IP stacks in the future.
|
|
- The APIs it provides are thread safe, even if the underlying TCP/IP stack APIs are not.
|
|
|
|
ESP-IDF currently implements ESP-NETIF for the lwIP TCP/IP stack only. However, the adapter itself is TCP/IP implementation agnostic and different implementations are possible.
|
|
|
|
Some ESP-NETIF API functions are intended to be called by application code, for example to get/set interface IP addresses, configure DHCP. Other functions are intended for internal ESP-IDF use by the network driver layer.
|
|
|
|
In many cases, applications do not need to call ESP-NETIF APIs directly as they are called from the default network event handlers.
|
|
|
|
ESP-NETIF component is a successor of the tcpip_adapter, former network interface abstraction, which has become deprecated since IDF v4.1.
|
|
Please refer to the :doc:`/api-reference/network/tcpip_adapter_migration` section in case existing applications to be ported to use the esp-netif API instead.
|
|
|
|
ESP-NETIF architecture
|
|
----------------------
|
|
|
|
.. code-block:: text
|
|
|
|
| (A) USER CODE |
|
|
| |
|
|
.............| init settings events |
|
|
. +----------------------------------------+
|
|
. . | *
|
|
. . | *
|
|
--------+ +===========================+ * +-----------------------+
|
|
| | new/config get/set | * | |
|
|
| | |...*.....| init |
|
|
| |---------------------------| * | |
|
|
init | | |**** | |
|
|
start |********| event handler |*********| DHCP |
|
|
stop | | | | |
|
|
| |---------------------------| | |
|
|
| | | | NETIF |
|
|
+-----| | | +-----------------+ |
|
|
| glue|----<---| esp_netif_transmit |--<------| netif_output | |
|
|
| | | | | | |
|
|
| |---->---| esp_netif_receive |-->------| netif_input | |
|
|
| | | | + ----------------+ |
|
|
| |....<...| esp_netif_free_rx_buffer |...<.....| packet buffer |
|
|
+-----| | | | |
|
|
| | | | (D) |
|
|
(B) | | (C) | +-----------------------+
|
|
--------+ +===========================+
|
|
communication NETWORK STACK
|
|
DRIVER ESP-NETIF
|
|
|
|
|
|
Data and event flow in the diagram
|
|
----------------------------------
|
|
|
|
* ``........`` Initialization line from user code to ESP-NETIF and communication driver
|
|
|
|
* ``--<--->--`` Data packets going from communication media to TCP/IP stack and back
|
|
|
|
* ``********`` Events aggregated in ESP-NETIF propagates to driver, user code and network stack
|
|
|
|
* ``|`` User settings and runtime configuration
|
|
|
|
ESP-NETIF interaction
|
|
---------------------
|
|
|
|
A) User code, boiler plate
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
Overall application interaction with a specific IO driver for communication media and configured TCP/IP network stack
|
|
is abstracted using ESP-NETIF APIs and outlined as below:
|
|
|
|
A) Initialization code
|
|
|
|
1) Initializes IO driver
|
|
2) Creates a new instance of ESP-NETIF and configure with
|
|
|
|
* ESP-NETIF specific options (flags, behaviour, name)
|
|
* Network stack options (netif init and input functions, not publicly available)
|
|
* IO driver specific options (transmit, free rx buffer functions, IO driver handle)
|
|
|
|
3) Attaches the IO driver handle to the ESP-NETIF instance created in the above steps
|
|
4) Configures event handlers
|
|
|
|
* use default handlers for common interfaces defined in IO drivers; or define a specific handlers for customised behaviour/new interfaces
|
|
* register handlers for app related events (such as IP lost/acquired)
|
|
|
|
B) Interaction with network interfaces using ESP-NETIF API
|
|
|
|
* Getting and setting TCP/IP related parameters (DHCP, IP, etc)
|
|
* Receiving IP events (connect/disconnect)
|
|
* Controlling application lifecycle (set interface up/down)
|
|
|
|
Please note that the initialization code as well as registering event handlers for default interfaces,
|
|
such as WiFi softAP and WiFi station, are provided as a separate APIs (for example ``esp_netif_create_default_wifi_ap()`` and
|
|
``esp_netif_create_default_wifi_sta()``) to facilitate simple startup code for most applications.
|
|
|
|
|
|
B) Communication driver, IO driver, media driver
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
Communication driver plays these two important roles in relation with ESP-NETIF:
|
|
|
|
1) Event handlers: Define behaviour patterns of interaction with ESP-NETIF (for example: ethernet link-up -> turn netif on)
|
|
|
|
2) Glue IO layer: Adapts the input/output functions to use ESP-NETIF transmit, receive and free receive buffer
|
|
|
|
* Installs driver_transmit to appropriate ESP-NETIF object, so that outgoing packets from network stack are passed to the IO driver
|
|
* Calls ``esp_netif_receive()`` to pass incoming data to network stack
|
|
|
|
|
|
C) ESP-NETIF, former tcpip_adapter
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
ESP-NETIF is an intermediary between an IO driver and a network stack, connecting packet data path between these two.
|
|
As that it provides a set of interfaces for attaching a driver to ESP-NETIF object (runtime) and
|
|
configuring a network stack (compile time). In addition to that a set of API is provided to control network interface lifecycle
|
|
and its TCP/IP properties. As an overview, the ESP-NETIF public interface could be divided into these 6 groups:
|
|
|
|
1) Initialization APIs (to create and configure ESP-NETIF instance)
|
|
2) Input/Output API (for passing data between IO driver and network stack)
|
|
3) Event or Action API
|
|
|
|
* Used for network interface lifecycle management
|
|
* ESP-NETIF provides building blocks for designing event handlers
|
|
|
|
4) Setters and Getters for basic network interface properties
|
|
5) Network stack abstraction: enabling user interaction with TCP/IP stack
|
|
|
|
* Set interface up or down
|
|
* DHCP server and client API
|
|
* DNS API
|
|
|
|
6) Driver conversion utilities
|
|
|
|
|
|
D) Network stack
|
|
^^^^^^^^^^^^^^^^
|
|
|
|
Network stack has no public interaction with application code with regard to public interfaces and shall be fully abstracted by
|
|
ESP-NETIF API.
|
|
|
|
|
|
|
|
API Reference
|
|
-------------
|
|
|
|
.. include:: /_build/inc/esp_netif.inc
|
|
|