Overview
========
The lwip_ipv4_ipv6_echo application demonstrates a TCP and UDP echo on the lwIP TCP/IP stack with FreeRTOS.
The demo can use both TCP or UDP protocol over IPv4 or IPv6 and acts as an echo server. The application sends back
the packets received from the PC, which can be used to test whether a TCP or UDP connection is available.
A few notes about IPv6
The demo generates a link-local address after the start. To send something to this (demo) address
from your computer you need to specify the interface over which the demo is reachable by appending % followed by zone index.
- On Windows, the zone index is a number. You can get it from the output of the ipconfig command.
- On Linux, the zone index is an interface name.
To connect to board with address FE80::12:13FF:FE10:1511
- over interface 21 on your Windows machine specify address as FE80::12:13FF:FE10:1511%21
- over interface eth on your Linux or Mac machine specify address as FE80::12:13FF:FE10:1511%eth0
But the demo has only a single interface, so do not append zone ID to any address typed to the demo terminal.
The LwIP stack is trying to get an IPv6 address automatically by neighbor discovery in the background.
This takes some time. You can print all addresses using the command print_ip_cfg any time.
Tools
It is necessary to have installed tools capable of sending and receiving data over TCP or UDP to interact with the demo.
- ncat - Recommended tool. Supports both IPv4 and IPv6. It is part of nmap tools. It can be found at https://nmap.org/download.html.
- nc (netcat) - Basically, the same as ncat, but a lot of antiviruses consider this a virus.
- echotool - Supports only IPv4 and only for Windows. It can be obtained from https://github.com/PavelBansky/EchoTool
Toolchain supported
===================
- IAR embedded Workbench 9.30.1
- Keil MDK 5.37
- GCC ARM Embedded 10.3.1
- MCUXpresso 11.6.0
Hardware requirements
=====================
- Mini/micro USB cable
- Network cable RJ45 standard
- EVK-MIMXRT1020 board
- Personal Computer
Board settings
==============
No special settings are required.
Note:
To debug in qspiflash, following steps are needed:
1. Select the flash target and compile.
2. Set the SW8: 1 off 2 off 3 on 4 off, then power on the board and connect USB cable to J23.
3. Start debugging in IDE.
- Keil: Click "Download (F8)" to program the image to qspiflash first then clicking "Start/Stop Debug Session (Ctrl+F5)" to start debugging.
Prepare the Demo
================
1. Connect a USB cable between the PC host and the OpenSDA(or USB to Serial) USB port on the target board.
2. Open a serial terminal on PC for OpenSDA serial(or USB to Serial) device with these settings:
- 115200 baud rate
- 8 data bits
- No parity
- One stop bit
- No flow control
3. Insert the Ethernet Cable into the target board's RJ45 port and connect it to your PC network adapter.
4. Configure the host PC IP address to 192.168.0.100.
5. Download the program to the target board.
7. Either press the reset button on your board or launch the debugger in your IDE to begin running the demo.
Running the demo
================
1. When the demo runs, the log would be seen on the terminal like:
Initializing PHY...
Copyright 2020 NXP
SHELL>>
2. There are several options what can you do. Type help command to see them all:
"help": List all the registered commands
"exit": Exit program
"echo_tcp_client ip_addr port":
Connects to specified server and sends back every received data.
Usage:
ip_addr: IPv6 or IPv4 server address
port: TCP port number
"echo_tcp_server port":
Listens for incoming connection and sends back every received data.
Usage:
port: TCP port number
"echo_udp port":
Waits for datagrams and sends them back.
Usage:
port: UDP port number
"end": Ends echo_* command.
"print_ip_cfg": Prints IP configuration.
3. TCP client echo
a) Launch ncat -v -l -p 10001 on your computer.
b) Run command echo_tcp_client 192.168.0.100 10001 in demo shell.
c) You should see on your PC "Ncat: Connection from 192.168.0.102."
d) Type some text into ncat (not demo shell) and the demo will send your line back
when you hit enter.
e) You can terminate connection by pressing ctrl+c in ncat or typing end to demo shell.
For IPv6 just replace 192.168.0.100 with IPv6 address of your PC.
4. TCP server echo
a) Run command echo_tcp_server 10001 in demo shell.
b) Launch ncat -v 192.168.0.102 10001 on your computer.
c) You should see on your PC "Ncat: Connected to 192.168.0.102:10001."
d) Type some text into ncat (not demo shell) and the demo will send your line back
when you hit enter.
e) You can terminate connection by pressing ctrl+c in ncat or typing end to demo shell.
For IPv6 just replace 192.168.0.102 with IPv6 address of demo FE80::12:13FF:FE10:1511%<zone ID>.
5. UDP echo
a) Run command echo_udp 10001 in demo shell.
b) On your computer launch ncat -v -u 192.168.0.102 10001
c) You should see on your PC "Ncat: Connected to 192.168.0.102:10001."
d) Type some text into ncat (not demo shell) and the demo will send your line back
when you hit enter.
e) To terminate is necessary by doing both, pressing ctrl+c in ncat and typing end to demo shell.
For IPv6 just replace 192.168.0.102 with IPv6 address of demo FE80::12:13FF:FE10:1511%<zone ID>.
