234 lines
6.7 KiB
ReStructuredText
234 lines
6.7 KiB
ReStructuredText
.. include:: /substitutions.rst
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.. _simulator:
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Simulator
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=========
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Apache NuttX has a simulator that can run as a regular program on Linux, Mac, and Windows computers.
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It's useful for debugging operating system features that aren't associated with particular
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device drivers— for instance the TCP/IP stack itself, a web interface or API for your
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application, or other communication protocols. It's also handy for trying out Apache NuttX without
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having a piece of embedded hardware.
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This guide assumes you're on Linux. It works on Windows and Mac too— if you know how,
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submit a PR to improve this guide!
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.. todo:: Add Mac and Windows instructions
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Compiling
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---------
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#. Configure the Simulator
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There are a lot of simulator configurations available that set you up to test various
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operating system features.
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Here we'll use the ``sim:nsh`` basic NuttX Shell configuration.
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.. code-block:: console
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$ cd nuttx
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$ ./tools/configure.sh sim:nsh
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#. Compile
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.. code-block:: console
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$ make
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#. Run the simulator:
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.. code-block:: console
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$ ./nuttx
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login: admin
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password: Administrator
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User Logged-in!
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NuttShell (NSH) NuttX-9.1.0
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MOTD: username=admin password=Administrator
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nsh> help
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help usage: help [-v] [<cmd>]
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[ cp exit losetup mv rmdir true
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? cmp false ls mw set uname
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basename dirname free mb poweroff sh unset
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break dd help mkdir ps sleep usleep
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cat echo hexdump mkfatfs pwd test xd
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cd exec kill mh rm time
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Builtin Apps:
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hello nsh
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nsh>
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#. Stop the simulator:
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.. code-block:: console
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nsh> poweroff
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$
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$ # we're back at the Linux prompt.
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Accessing the Network
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---------------------
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#. Here we'll use the ``sim:tcpblaster`` configuration because it comes with networking
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that is ready to use.
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.. code-block:: console
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$ make distclean
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$ ./tools/configure.sh sim:tcpblaster
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$ make
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#. Give the Simulator Privileges
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On recent Linux distributions, you need to give the ``nuttx`` program the capabilities
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(similar to permissions) to access the network:
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.. code-block:: console
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$ sudo setcap cap_net_admin+ep ./nuttx
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#. Run the simulator:
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.. code-block:: console
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$ ./nuttx
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#. Bring Up the Network Interfaces
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On Apache NuttX:
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.. code-block:: console
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nsh> ifup eth0
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On Linux, first you need to find your main network interface— this will usually either
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be an ethernet or wireless network adapter. Do this:
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.. code-block:: console
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$ ifconfig
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lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
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inet 127.0.0.1 netmask 255.0.0.0
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inet6 ::1 prefixlen 128 scopeid 0x10<host>
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loop txqueuelen 1000 (Local Loopback)
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RX packets 5846 bytes 614351 (614.3 KB)
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RX errors 0 dropped 0 overruns 0 frame 0
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TX packets 5846 bytes 614351 (614.3 KB)
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TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
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wlp0s20f3: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
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inet 192.168.1.209 netmask 255.255.255.0 broadcast 192.168.1.255
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inet6 fe80::1161:c26b:af05:d784 prefixlen 64 scopeid 0x20<link>
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ether 24:41:8c:a8:30:d1 txqueuelen 1000 (Ethernet)
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RX packets 219369 bytes 176416490 (176.4 MB)
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RX errors 0 dropped 0 overruns 0 frame 0
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TX packets 108399 bytes 27213617 (27.2 MB)
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TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
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``lo0`` is the Loopback Interface, so ``wlp0s20f3`` is the wireless interface. Note
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that it has an IP address on the local net. There may be other interfaces listed, you'll
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need to pick the one that's right for your system.
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Then, on Linux do this to set up the tap network interface and route that will let
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the Apache NuttX simulator access the network:
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.. code-block:: console
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$ sudo ./tools/simhostroute.sh wlp0s20f3 on
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$ ping -c 1 10.0.1.2 # nuttx system
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PING 10.0.1.2 (10.0.1.2) 56(84) bytes of data.
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64 bytes from 10.0.1.2: icmp_seq=1 ttl=64 time=7.52 ms
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--- 10.0.1.2 ping statistics ---
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1 packets transmitted, 1 received, 0% packet loss, time 0ms
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rtt min/avg/max/mdev = 7.529/7.529/7.529/0.000 m
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#. Test that Apache NuttX can access the Internet
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First let's ping the network interface of our Linux host to prove we can see the
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gateway to the Internet:
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.. code-block:: console
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nsh> ping -c 1 10.0.1.1
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nsh> ping -c 1 10.0.1.1
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PING 10.0.1.1 56 bytes of data
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56 bytes from 10.0.1.1: icmp_seq=0 time=0 ms
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1 packets transmitted, 1 received, 0% packet loss, time 1010 ms
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Now let's ping one of Google's DNS servers to prove we can access the rest of the
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Internet:
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.. code-block:: console
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nsh> ping -c 1 8.8.8.8
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PING 8.8.8.8 56 bytes of data
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56 bytes from 8.8.8.8: icmp_seq=0 time=10 ms
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1 packets transmitted, 1 received, 0% packet loss, time 1010 ms
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Success!
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Testing / capturing TCP network traffic
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---------------------------------------
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#. Start Wireshark (or tcpdump) on Linux and capture the appeared tap0 interface.
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#. Optionally activate emulating packet loss on Linux:
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.. code-block:: console
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$ sudo iptables -A INPUT -p tcp --dport 31337 -m statistic --mode random --probability 0.01 -j DROP
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#. Run netcat server on Linux:
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.. code-block:: console
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$ netcat -l -p 31337
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#. Run netcat client on Apache NuttX:
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.. code-block:: console
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nsh> dd if=/dev/zero of=/tmp/test.bin count=1000
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nsh> netcat LINUX_HOST_IP_ADDRESS 31337 /tmp/test.bin
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#. Observe TCP network traffic in Wireshark / tcpdump on Linux.
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Stopping
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--------
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#. The normal way to stop:
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.. code-block:: console
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nsh> poweroff
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$
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$ # we're back at the Linux prompt.
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If you don't have an nsh prompt, the only effective way to stop the simulator is kill it from another terminal:
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.. code-block:: console
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$ pkill nuttx
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#. Optionally deactivate emulating packet loss on Linux:
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.. code-block:: console
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$ sudo iptables -D INPUT -p tcp --dport 31337 -m statistic --mode random --probability 0.01 -j DROP
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#. If you do not need tap0 interface anymore, it can be disabled on Linux as follows:
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.. code-block:: console
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$ sudo ./tools/simhostroute.sh wlan0 off
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Debugging
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---------
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You can debug the simulator like any regular Linux program.
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