Ip Network Layer - Espressif ESP32-S2 Programming Manual

Chapter 2. API Reference

2.1.4 IP Network Layer

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
to be ported to use the esp-netif API instead.
ESP-NETIF architecture
|
|
.............| init
. +----------------------------------------+
.
.
--------+ +===========================+
| | new/config
| |
| |---------------------------|
init | |
start |********|
stop | |
| |---------------------------|
| |
+-----| |
| glue|----<---|
| | |
| |---->---|
| | |
| |....<...|
+-----| |
| |
(B) | |
--------+ +===========================+
communication
DRIVER
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
Espressif Systems
TCP/IP Adapter Migration Guide
(A) USER CODE
settings
. |
. |
get/set
event handler
esp_netif_transmit
esp_netif_receive
esp_netif_free_rx_buffer |...<.....| packet buffer
(C)
ESP-NETIF
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section in case existing applications
|
|
events |
*
*
* +-----------------------+
| * |
|...*.....| init
* |
|**** |
|*********| DHCP
| |
|
| |
| +-----------------+
|--<------| netif_output
| |
|-->------| netif_input
| + ----------------+
| |
| |
| +-----------------------+
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NETIF |
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(D) |
NETWORK STACK
Release v4.4