Socket Echo Client¶
The echo-client sample application for Zephyr implements a UDP/TCP client that will send IPv4 or IPv6 packets, wait for the data to be sent back, and then verify it matches the data that was sent.
This sample is a port of the Echo Client. It has been rewritten to use socket API instead of native net-app API.
The source code for this sample application can be found at:
Building and Running¶
There are multiple ways to use this application. One of the most common usage scenario is to run echo-client application inside QEMU. This is described in Networking with QEMU.
Build echo-client sample application like this:
# On Linux/macOS cd $ZEPHYR_BASE/samples/net/sockets/echo_client mkdir build && cd build # On Windows cd %ZEPHYR_BASE%\samples\net\sockets\echo_client mkdir build & cd build cmake -GNinja -DBOARD=<board_to_use> .. ninja
board_to_use defaults to
qemu_x86. In this case, you can run the
application in QEMU using
make run. If you used another BOARD, you
will need to consult its documentation for application deployment
instructions. You can read about Zephyr support for specific boards in
the documentation at Supported Boards.
Enabling TLS support¶
Enable TLS support in the sample by building the project with the
overlay-tls.conf overlay file enabled, for example, using these commands:
# On Linux/macOS cd $ZEPHYR_BASE/samples/net/sockets/echo_client mkdir build && cd build # On Windows cd %ZEPHYR_BASE%\samples\net\sockets\echo_client mkdir build & cd build cmake -GNinja -DBOARD=qemu_x86 -DCONF_FILE="prj.conf overlay-tls.conf" .. ninja
An alternative way is to specify
The certificate and private key used by the sample can be found in the sample’s
src directory. The default certificates used by Socket Echo Client and
Socket Echo Server enable establishing a secure connection
between the samples.
Running echo-server in Linux Host¶
There is one useful testing scenario that can be used with Linux host. Here echo-client is run in QEMU and echo-server is run in Linux host.
To use QEMU for testing, follow the Networking with QEMU guide.
In a terminal window:
$ sudo ./echo-server -i tap0
Run echo-client application in QEMU:
cd $ZEPHYR_BASE/samples/net/sockets/echo_client mkdir build && cd build cmake -GNinja -DBOARD=qemu_x86 .. ninja run
Note that echo-server must be running in the Linux host terminal window before you start the echo-client application in QEMU.
You can verify TLS communication with a Linux host as well. See https://github.com/zephyrproject-rtos/net-tools documentation for information on how to test TLS with Linux host samples.
See the Socket Echo Server documentation for an alternate way of running, with the echo-client on the Linux host and the echo-server in QEMU.