185 lines
4.6 KiB
ReStructuredText
185 lines
4.6 KiB
ReStructuredText
.. _dns-resolve-sample:
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DNS Resolve Application
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#######################
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Overview
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********
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The DNS resolver sample application implements a basic DNS resolver according
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to RFC 1035. Supported DNS answers are IPv4/IPv6 addresses and CNAME.
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If a CNAME is received, the DNS resolver will create another DNS query.
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The number of additional queries is controlled by the
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DNS_RESOLVER_ADDITIONAL_QUERIES Kconfig variable.
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The multicast DNS (mDNS) client resolver support can be enabled by setting
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CONFIG_MDNS_RESOLVER Kconfig variable.
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See https://tools.ietf.org/html/rfc6762 for more details about mDNS.
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For more information about DNS configuration variables, see:
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:file:`subsys/net/lib/dns/Kconfig`. The DNS resolver API can be found at
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:file:`include/net/dns_resolve.h`. The sample code can be found at:
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:file:`samples/net/dns_resolve`.
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Requirements
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************
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- :ref:`networking_with_qemu`
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- screen terminal emulator or equivalent.
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- For the Arduino 101 board, the ENC28J60 Ethernet module is required.
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- dnsmasq application. The dnsmasq version used in this sample is:
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.. code-block:: console
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dnsmasq -v
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Dnsmasq version 2.76 Copyright (c) 2000-2016 Simon Kelley
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Building and Running
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********************
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Network Configuration
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=====================
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Open the project configuration file for your platform, for example:
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:file:`prj_frdm_k64f.conf` is the configuration file for the
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:ref:`frdm_k64f` board.
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In this sample application, both static or DHCPv4 IP addresses are supported.
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Static IP addresses are specified in the project configuration file,
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for example:
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.. code-block:: console
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CONFIG_NET_APP_MY_IPV6_ADDR="2001:db8::1"
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CONFIG_NET_APP_PEER_IPV6_ADDR="2001:db8::2"
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are the IPv6 addresses for the DNS client running Zephyr and the DNS server,
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respectively.
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DNS server
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==========
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The dnsmasq tool may be used for testing purposes. Sample dnsmasq start
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script can be downloaded from the zephyrproject-rtos/net-tools project area:
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https://github.com/zephyrproject-rtos/net-tools
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Open a terminal window and type:
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.. code-block:: console
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$ cd net-tools
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$ sudo ./dnsmasq.sh
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The default project configurations settings for this sample uses the public
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Google DNS servers. In order to use the local dnsmasq server, please edit
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the appropriate 'prj.conf' file and update the DNS server addresses. For
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instance, if using the usual IP addresses assigned to testing, update them
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to the following values:
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.. code-block:: console
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CONFIG_DNS_SERVER1="192.0.2.2:5353"
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CONFIG_DNS_SERVER2="[2001:db8::2]:5353"
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.. note::
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DNS uses port 53 by default, but the dnsmasq.conf file provided by
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net-tools uses port 5353 to allow executing the daemon without
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superuser privileges.
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If dnsmasq fails to start with an error like this:
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.. code-block:: console
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dnsmasq: failed to create listening socket for port 5353: Address already in use
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Open a terminal window and type:
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.. code-block:: console
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$ killall -s KILL dnsmasq
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Try to launch the dnsmasq application again.
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For testing mDNS, use Avahi script in net-tools project:
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.. code-block:: console
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$ cd net-tools
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$ ./avahi-daemon.sh
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QEMU x86
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========
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To use QEMU for testing, follow the :ref:`networking_with_qemu` guide.
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FRDM K64F
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=========
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Open a terminal window and type:
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.. zephyr-app-commands::
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:zephyr-app: samples/net/dns_resolve
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:board: frdm_k64f
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:goals: build flash
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:compact:
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See :ref:`Freedom-K64F board documentation <frdm_k64f>` for more information
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about this board.
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Open a terminal window and type:
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.. code-block:: console
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$ screen /dev/ttyACM0 115200
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Use 'dmesg' to find the right USB device.
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Once the binary is loaded into the FRDM board, press the RESET button.
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Arduino 101
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===========
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Open a terminal window and type:
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.. zephyr-app-commands::
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:zephyr-app: samples/net/dns_resolve
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:board: arduino_101
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:goals: build
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:compact:
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To load the binary in the development board follow the steps
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in :ref:`arduino_101`.
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Open a terminal window and type:
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.. code-block:: console
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$ screen /dev/ttyUSB0 115200
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Use 'dmesg' to find the right USB device.
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Once the binary is loaded into the Arduino 101 board, press the RESET button.
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The ENC28J60 module is an Ethernet device with SPI interface.
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The following pins must be connected from the ENC28J60 device to the
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Arduino 101 board:
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=========== ===================================
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Arduino 101 ENC28J60 (pin numbers on the board)
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=========== ===================================
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D13 SCK (1)
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D12 SO (3)
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D11 SI (2)
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D10 CS (7)
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D04 INT (5)
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3.3V VCC (10)
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GDN GND (9)
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=========== ===================================
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