A small tool that uses GNRC TCP of RIOT to listen on a specific port. It can handle a single connection at a time and simply prints all messages received.
You can use this tool for testing on native Linux and macOS. First, setup local networking for the test:
</path/to/riot>/dist/tools/tapsetup/tapsetup -c 1
Second, build and run the tcp_listen tool with RIOT on native.
Ensure that RIOTBASE is set or provide the path when calling make, like:
export RIOTBASE=</path/to/riot>
make && make term
Copy the lladdr of the RIOT node that is printed to the console and open another terminal where you run netcat, as follows with the given port (default: 24911):
nc -6 <lladdr-of-riot>%bridge0 <port>
Now you can send strings from your host via netcat to the RIOT node, which prints the messages.
You can use wireshark or tcpdump to sniff the network traffic, e.g.:
sudo tcpdump -i bridge0 tcp