Chapter 146. Tests and Demonstrations
Table of Contents
146.1. Loopback tests
By default, only tests which can execute on any target will be built. These therefore do not actually use external network interfaces (though they may configure and initialize them) but are limited to testing via the loopback interface.
ping_lo_test - ping test of the loopback address tcp_lo_select - simple test of select with TCP via loopback tcp_lo_test - trivial TCP test via loopback udp_lo_test - trivial UDP test via loopback multi_lo_select - test of multiple select() calls simultaneously
146.2. Building the Network Tests
To build further network tests, ensure that the configuration option CYGPKG_NET_BUILD_TESTS is set in your build and then make the tests in the usual way. Alternatively (with that option set) use the following command after building the eCos library, if you wish to build only the network tests:
make -C net/common/
This should give test executables in
socket_test - trivial test of socket creation API mbuf_test - trivial test of mbuf allocation API ftp_test - simple FTP test, connects to “server” ping_test - pings “server” and non-existent host to test timeout dhcp_test - ping test, but also relinquishes and reacquires DHCP leases periodically flood - a flood ping test; use with care tcp_echo - data forwarding program for performance test nc_test_master - network characterization master nc_test_slave - network characterization slave server_test - a very simple server example tftp_client_test - performs a tftp get and put from/to “server” tftp_server_test - runs a tftp server for a short while set_mac_address - set MAC address(es) of interfaces in NVRAM bridge - contributed network bridge code nc6_test_master - IPv4/IPv6 network characterization master nc6_test_slave - IPv4/IPv6 network characterization slave ga_server_test - a very simple IPv4/IPv6 server example
146.3. Standalone Tests
socket_test - trivial test of socket creation API mbuf_test - trivial test of mbuf allocation API
These two do not communicate over the net; they just perform simple API tests then exit.
ftp_test - simple FTP test, connects to “server”
This test initializes the interface(s) then connects to the FTP server on the “server” machine for for each active interface in turn, confirms that the connection was successful, disconnects and exits. This tests interworking with the server.
ping_test - pings “server” and non-existent host to test timeout
This test initializes the interface(s) then pings the server machine in the standard way, then pings address “32 up” from the server in the expectation that there is no machine there. This confirms that the successful ping is not a false positive, and tests the receive timeout. If there is such a machine, of course the 2nd set of pings succeeds, confirming that we can talk to a machine not previously mentioned by configuration or by bootp. It then does the same thing on the other interface, eth1.
If IPv6 is enabled, the program will also ping to the address it last received a router advertisement from. Also a ping will be made to that address plus 32, in a similar way the the IPv4 case.
dhcp_test - ping test, but also manipulates DHCP leases
This test is very similar to the ping test, but in addition, provided the network package is not configured to do this automatically, it manually relinquishes and reclaims DHCP leases for all available interfaces. This tests the external API to DHCP. See section below describing this.
flood - a flood ping test; use with care
This test performs pings on all interfaces as quickly as possible, and only prints status information periodically. Flood pinging is bad for network performance; so do not use this test on general purpose networks unless protected by a switch.
146.4. Performance Test
tcp_echo - data forwarding program for performance test
tcp_echo is one
part of the standard performance test we use. The other parts are
To make these (under your HOST system) cd to the tests source directory in
the eCos repository and type “
make -f make.host” -
this should build
The host program “
data to the target. On the target, “
it onwards to “
on your host. So the target must receive and send on all the data that
it; the time taken for this is measured and the data rate is calculated.
To invoke the test, first start
the target board and wait for it to become quiescent - it will report
work to calibrate a CPU load which can be used to simulate real
operating conditions for the stack.
Then on your host machine, in one terminal window, invoke
it the IP address (or hostname) of one interface of the target board.
For example “
tcp_echo on the target
will print something like “
from 10.130.39.13:1143” when
Next, in another host terminal window, invoke
giving it the IP address (or hostname) of an interface of the target
board, and optionally a background load to apply to the target while
the test runs. For example, “
220.127.116.11” to run the test with no
additional target CPU load, or “
18.104.22.168 85” to load it up to 85% used.
The target load must be a multiple of 5.
the target will print something like “
connection from 22.214.171.124:1144” when
tcp_source is correctly invoked.
You can connect tcp_sink to one target interface
and tcp_source to another, or both to the same interface.
Similarly, you can run
the same host machine or different ones. TCP/IP and ARP
look after them finding one another, as intended.
nc_test_master - network characterization master nc_test_slave - network characterization slave
These tests talk to each other to measure network performance.
They can each run on either a test target or a host computer
given some customization to your local environment. As provided,
run on the test target, and
be run on a host computer, and be given the test target's
IP address or hostname.
The tests print network performance for various packet sizes over UDP and TCP, versus various additional CPU loads on the target.
The programs below are additional forms which support both IPv4 and IPv6 addressing:
146.5. Interactive Tests
server_test - a very simple server example
This test simply awaits a connection on port 7734 and after accepting a connection, gets a packet (with a timeout of a few seconds) and prints it.
The connection is then closed. We then loop to await the next connection, and so on. To use it, telnet to the target on port 7734 then type something (quickly!)
% telnet 172.16.19.171 7734 Hello target board
and the test program will print something like:
connection from 172.16.19.13:3369 buf = "Hello target board"
ga_server_test - another very simple server example
This is a variation on the ga_server_test test
with the difference being that it uses the
function to set up its addresses. On a system with IPv6 enabled, it will
listen on port 7734 for a TCP connection via either IPv4 or IPv6.
tftp_client_test - performs a tftp get and put from/to “server”
This is only partially interactive. You need to set things up on the “server” in order for this to work, and you will need to look at the server afterwards to confirm that all was well.
For each interface in turn, this test attempts to read by
tftp from the server, a file called
prints the status and contents it read (if any). It then writes
the same data to a file called
the same server.
In order for this to succeed, both files must already exist. The TFTP protocol does not require that a WRQ request _create_ a file, just that it can write it. The TFTP server on Linux certainly will only allow writes to an existing file, given the appropriate permission. Thus, you need to have these files in place, with proper permission, before running the test.
The conventional place for the tftp server to operate in LINUX
is /tftpboot/; you will likely need root privileges
to create files there. The data contents of
be anything you like, but anything very large will waste lots of
time printing it on the test‚s stdout, and anything above
32kB will cause a buffer overflow and unpredictable failure.
Creating an empty tftp_put file (eg. by copying /dev/null to it) is neatest. So before the test you should have something like:
-rw-rw-rw- 1 root 1076 May 1 11:39 tftp_get -rw-rw-rw- 1 root 0 May 1 15:52 tftp_put
note that both files have public permissions wide open. After
running the test,
be a copy of
-rw-rw-rw- 1 root 1076 May 1 11:39 tftp_get -rw-rw-rw- 1 root 1076 May 1 15:52 tftp_put
If the configuration contains IPv6 support, the test program will also use IPv6. It will attempt to put/get the files listed above from the address it last received a routers solicit from.
tftp_server_test - runs a tftp server for a short while
This test is truly interactive, in that you can use a standard tftp application to get and put files from the server, during the 5 minutes that it runs. The dummy filesystem which underlies the server initially contains one file, called “uu” which contains part of a familiar text and some padding. It also accommodates creation of 3 further files of up to 1Mb in size and names of up to 256 bytes. Exceeding these limits will cause a buffer overflow and unpredictable failure.
The dummy filesystem is an implementation of the generic API which allows a true filesystem to be attached to the tftp server in the network stack.
We have been testing the tftp server by running the test on the target board, then using two different host computers connecting to the different target interfaces, putting a file from each, getting the “uu” file, and getting the file from the other computer. This verifies that data is preserved during the transfer as well as interworking with standard tftp applications.
146.6. Maintenance Tools
set_mac_address - set MAC address(es) of interfaces in NVRAM
This program makes an example
“Socket IO Set InterFace HardWare ADDRess”
to set the MAC address on targets
where this is supported and enabled in the configuration. You must
edit the source to choose a MAC address and further edit it to allow
this very dangerous operation. Not all ethernet drivers support
this operation, because most ethernet hardware does not support
it — or it comes pre-set from the factory.
Do not use this program.
|2023-01-12||Open Publication License|