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 TCP/IP Adapter Migration Guide section in case existing applications
to be ported to use the esp-netif API instead.
ESP-NETIF architecture
| (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
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