New component ESP-PPP-Link

[david-cermak]

ESP-PPP-Link (eppp_link)

Introducing a general purpose connectivity component to share network between two endpoints: PPP server and PPP client. This component implements both roles on ESP32 using UART and SPI transport.
Since the connection is standard PPPoS, the endpoints could be any other micro-controllers or a linux host running pppd

Typical use case

Bring WiFi connectivity to endpoints that do not support WiFi

             SLAVE micro                                  HOST micro
    \|/  +----------------+                           +----------------+
     |   |                |          serial line      |                |
     +---+ WiFi NAT PPPoS |======== UART / SPI =======| PPPoS client   |
         |        (server)|                           |                |
         +----------------+                           +----------------+

API

Client

• eppp_connect() -- Simplified API. Provides the initialization, starts the task and blocks until we're connected

Server

• eppp_listen() -- Simplified API. Provides the initialization, starts the task and blocks until the client connects

Manual actions

• eppp_init() -- Initializes one endpoint (client/server).
• eppp_deinit() -- Destroys the endpoint
• eppp_netif_start() -- Starts the network, could be called after startup or whenever a connection is lost
• eppp_netif_stop() -- Stops the network
• eppp_perform() -- Perform one iteration of the PPP task (need to be called regularly in task-less configuration)

Throughput

Tested with WiFi-NAPT example, no IRAM optimizations

UART @ 3Mbauds

• TCP - 2Mbits
• UDP - 2Mbits

SPI @ 20MHz

• TCP - 6Mbits
• UDP - 10Mbits

TODO

• Add support for PPP server (and header compression) to IDF
• Add CI jobs (wait for IDF changes) add label
• Use console_ping and console_iperf components in examples

[euripedesrocha]

I noticed that eppp_link_types.h is empty, should it be removed?

[david-cermak]

Thanks @euripedesrocha for taking a look!

I noticed that eppp_link_types.h is empty, should it be removed?

Thanks, removed!

[gabsuren]

No high level README.md description, in the first page of esp-protocols