esp-protocols/components/esp_modem/examples/linux_modem/README.md

Linux modem example

This is an experimental port of the esp_modem to linux. It mocks some IDF functionality with port/linux layers (used for modem host test suite) and implements esp_netif, which supports tun interface and uses lwIP ppp implementation to parse or wrap IP packets to be send/receive over PPPoS, i.e. over the modem serial line.

Configuration

• Set path to the lwip and lwip_contrib repositories as environmental variables:
  • LWIP_PATH: path to the lwip repository
  • LWIP_CONTRIB_PATH: path to the lwip_contrib repository
• Create a tun interface using make_tun_netif script.
• Set SIO dev name directly in the code: This is the serial port which is the modem connected to
• (Set the tun device na interface name in the code: Not needed if the device was created using the script above.)
• Build and run the example (no elevated privileges needed)
• Experiment with the network, after getting the IP from the modem device
  • directly in the code
  • in the system (need to set tun interface IP, dns servers, and routing the desired traffic over the tun interface)

Supported IDF versions

This example (using the default CMake IDF build system) is only supported from v4.4, since is uses idf.py's linux target.