Is lwIP Socket API available for IoT app in nRF5 IoT SDK?

[danielkelly]

There are an example which based on Nordic's implementation of BSD Socket API (the client-side).

Also, I have seen the lwIP Socket API in nRF5 IoT SDK, but, there no app examples show how to use them. So, Is lwIP Socket API available to directly use in app? If so, how to use? If not, how to modify to support?

Thanks!

[tesc]

Hi,

The lwIP library in the IoT SDK is there to showcase the ability to run third-party stacks.

For instance the MQTT example uses lwIP based MQTT client applications on the nRF52, for both the Publisher and the Subscriber examples.

You will find three files using lwIP for libraries in the SDK:

• (iot sdk folder)/components/iot/coap/coap_transport_lwip.c
• (iot sdk folder)/components/iot/mqtt/mqtt_transport.c
• (iot sdk folder)/components/iot/socket/lwip/transport_handler.c

The last one looks promising for sockets.

Regards, Terje

[danielkelly]

Hi, Thanks for your answer. The function: transport_handler_init() is just called by socket_init in file :(iot sdk folder)/ iot/components/iot/socket/common/socket.c (That is nordic's socket) .

But, it is not used by lwip_socket. so, Is lwIP Socket API available?

[tesc]

Ah, I see. the lwIP library in (sdk folder)/external/lwip is a clone of version 1.4 of the gnu project (http://git.savannah.gnu.org/cgit/lwip.git/tree/?id=974f6982a124460de2c98c28186862a059e4682c). This means you can use the lwip socket api, provided that LWIP_SOCKET is true (i.e. defined to be 1).