87 lines
2.6 KiB
ReStructuredText
87 lines
2.6 KiB
ReStructuredText
.. zephyr:code-sample:: async-sockets-echo
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:name: Asynchronous echo server using poll()
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:relevant-api: bsd_sockets
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Implement an asynchronous IPv4/IPv6 TCP echo server using BSD sockets and poll()
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Overview
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********
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The sockets/echo-async sample application for Zephyr implements an
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asynchronous IPv4/IPv6 TCP echo server using a BSD Sockets compatible API
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with non-blocking sockets and a ``poll()`` call. This is an extension of
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the :zephyr:code-sample:`sockets-echo` sample. It's a more involved application,
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supporting both IPv4 and IPv6 with concurrent connections, limiting
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maximum number of simultaneous connections, and basic error handling.
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The source code for this sample application can be found at:
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:zephyr_file:`samples/net/sockets/echo_async`.
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Requirements
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************
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- :ref:`networking_with_host`
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- or, a board with hardware networking (including 6LoWPAN)
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Building and Running
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********************
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Build the Zephyr version of the sockets/echo_async application like this:
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.. zephyr-app-commands::
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:zephyr-app: samples/net/sockets/echo_async
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:board: <board_to_use>
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:goals: build
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:compact:
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After the sample starts, it expects connections at 192.0.2.1 (IPv4), or
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2001:db8::1 (IPv6), port 4242. The easiest way to connect is:
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.. code-block:: console
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$ telnet 192.0.2.1 4242 # use this for IPv4
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$ telnet 2001:db8::1 4242 # or this for IPv6
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After a connection is made, the application will echo back any line sent to
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it. Unlike the above-mentioned :zephyr:code-sample:`sockets-echo` sample, this application
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supports multiple concurrent client connections. You can open
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another terminal window and run the same telnet command as above.
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The sample supports up to three connected clients, but this can be adjusted
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by changing ``NUM_FDS`` defined in the source code.
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Wi-Fi
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=====
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The IPv4 Wi-Fi support can be enabled in the sample with
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:ref:`Wi-Fi snippet <snippet-wifi-ipv4>`.
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Running application on POSIX Host
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=================================
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The same application source code can be built for a POSIX system, e.g.
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Linux. (Note: if you look at the source, you will see that the code is
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the same except the header files are different for Zephyr vs POSIX, and
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there's an additional option to set for Linux to make a socket IPv6-only).
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To build:
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.. code-block:: console
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$ make -f Makefile.host
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To run:
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.. code-block:: console
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$ ./socket_echo
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To test:
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.. code-block:: console
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$ telnet 127.0.0.1 4242 # use this for IPv4
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$ telnet ::1 4242 # or this for IPv6
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As can be seen, the behavior of the application is the same as the Zephyr
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version.
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