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diff --git a/legacy-networking/testing_the_driver.rst b/legacy-networking/testing_the_driver.rst new file mode 100644 index 0000000..dbd1163 --- /dev/null +++ b/legacy-networking/testing_the_driver.rst @@ -0,0 +1,299 @@ +.. SPDX-License-Identifier: CC-BY-SA-4.0 + +.. COMMENT: Text Written by Jake Janovetz +.. Copyright (C) 1988, 2002 On-Line Applications Research Corporation (OAR) + +Testing the Driver +################## + +Preliminary Setup +================= + +The network used to test the driver should include at least: + +- The hardware on which the driver is to run. It makes testing much easier if + you can run a debugger to control the operation of the target machine. + +- An Ethernet network analyzer or a workstation with an 'Ethernet snoop' + program such as ``ethersnoop`` or ``tcpdump``. + +- A workstation. + +During early debug, you should consider putting the target, workstation, and +snooper on a small network by themselves. This offers a few advantages: + +- There is less traffic to look at on the snooper and for the target to process + while bringing the driver up. + +- Any serious errors will impact only your small network not a building or + campus network. You want to avoid causing any unnecessary problems. + +- Test traffic is easier to repeatably generate. + +- Performance measurements are not impacted by other systems on the network. + +Debug Output +============ + +There are a number of sources of debug output that can be enabled to aid in +tracing the behavior of the network stack. The following is a list of them: + +- mbuf activity + There are commented out calls to ``printf`` in the file ``sys/mbuf.h`` in the + network stack code. Uncommenting these lines results in output when mbuf's + are allocated and freed. This is very useful for finding memory leaks. + +- TX and RX queuing + There are commented out calls to ``printf`` in the file ``net/if.h`` in the + network stack code. Uncommenting these lines results in output when packets + are placed on or removed from one of the transmit or receive packet queues. + These queues can be viewed as the boundary line between a device driver and + the network stack. If the network stack is enqueuing packets to be + transmitted that the device driver is not dequeuing, then that is indicative + of a problem in the transmit side of the device driver. Conversely, if the + device driver is enqueueing packets as it receives them (via a call to + ``ether_input``) and they are not being dequeued by the network stack, then + there is a problem. This situation would likely indicate that the network + server task is not running. + +- TCP state transitions + + In the unlikely event that one would actually want to see TCP state + transitions, the ``TCPDEBUG`` macro can be defined in the file + ``opt_tcpdebug.h``. This results in the routine ``tcp_trace()`` being called + by the network stack and the state transitions logged into the ``tcp_debug`` + data structure. If the variable ``tcpconsdebug`` in the file + ``netinet/tcp_debug.c`` is set to ``1``, then the state transitions will also + be printed to the console. + +Monitor Commands +================ + +There are a number of command available in the shell / monitor to aid in +tracing the behavior of the network stack. The following is a list of them: + +- ``inet`` + This command shows the current routing information for the TCP/IP + stack. Following is an example showing the output of this command. + + .. code-block:: shell + + Destination Gateway/Mask/Hw Flags Refs Use Expire Interface + 10.0.0.0 255.0.0.0 U 0 0 17 smc1 + 127.0.0.1 127.0.0.1 UH 0 0 0 lo0 + + In this example, there is only one network interface with an IP address of + 10.8.1.1. This link is currently not up. Two routes that are shown are the + default routes for the Ethernet interface (10.0.0.0) and the loopback + interface (127.0.0.1). Since the stack comes from BSD, this command is very + similar to the netstat command. For more details on the network routing + please look the following URL: + (http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/network-routing.html) + For a quick reference to the flags, see the table below: + + '``U``' + Up: The route is active. + + '``H``' + Host: The route destination is a single host. + + '``G``' + Gateway: Send anything for this destination on to this remote system, + which will figure out from there where to send it. + + '``S``' + Static: This route was configured manually, not automatically generated + by the system. + + '``C``' + Clone: Generates a new route based upon this route for machines we + connect to. This type of route is normally used for local networks. + + '``W``' + WasCloned: Indicated a route that was auto-configured based upon a local + area network (Clone) route. + + '``L``' + Link: Route involves references to Ethernet hardware. + +- ``mbuf`` + This command shows the current MBUF statistics. An example of the command is + shown below: + + .. code-block:: shell + + ************ MBUF STATISTICS ************ + mbufs:4096 clusters: 256 free: 241 + drops: 0 waits: 0 drains: 0 + free:4080 data:16 header:0 socket:0 + pcb:0 rtable:0 htable:0 atable:0 + soname:0 soopts:0 ftable:0 rights:0 + ifaddr:0 control:0 oobdata:0 + +- ``if`` + This command shows the current statistics for your Ethernet driver as long as + the ioctl hook ``SIO_RTEMS_SHOW_STATS`` has been implemented. Below is an + example: + + .. code-block:: shell + + ************ INTERFACE STATISTICS ************ + ***** smc1 ***** + Ethernet Address: 00:12:76:43:34:25 + Address:10.8.1.1 Broadcast Address:10.255.255.255 Net mask:255.0.0.0 + Flags: Up Broadcast Running Simplex + Send queue limit:50 length:0 Dropped:0 + SMC91C111 RTEMS driver A0.01 11/03/2002 Ian Caddy (ianc@microsol.iinet.net.au) + Rx Interrupts:0 Not First:0 Not Last:0 + Giant:0 Runt:0 Non-octet:0 + Bad CRC:0 Overrun:0 Collision:0 + Tx Interrupts:2 Deferred:0 Missed Hearbeat:0 + No Carrier:0 Retransmit Limit:0 Late Collision:0 + Underrun:0 Raw output wait:0 Coalesced:0 + Coalesce failed:0 Retries:0 + ***** lo0 ***** + Address:127.0.0.1 Net mask:255.0.0.0 + Flags: Up Loopback Running Multicast + Send queue limit:50 length:0 Dropped:0 + +- ``ip`` + This command show the IP statistics for the currently configured interfaces. + +- ``icmp`` + This command show the ICMP statistics for the currently configured interfaces. + +- ``tcp`` + This command show the TCP statistics for the currently configured interfaces. + +- ``udp`` + This command show the UDP statistics for the currently configured interfaces. + +Driver basic operation +====================== + +The network demonstration program ``netdemo`` may be used for these tests. + +- Edit ``networkconfig.h`` to reflect the values for your network. + +- Start with ``RTEMS_USE_BOOTP`` not defined. + +- Edit ``networkconfig.h`` to configure the driver with an explicit Ethernet + and Internet address and with reception of broadcast packets disabled: Verify + that the program continues to run once the driver has been attached. + +- Issue a '``u``' command to send UDP packets to the 'discard' port. Verify + that the packets appear on the network. + +- Issue a '``s``' command to print the network and driver statistics. + +- On a workstation, add a static route to the target system. + +- On that same workstation try to 'ping' the target system. + Verify that the ICMP echo request and reply packets appear on the net. + +- Remove the static route to the target system. Modify ``networkconfig.h`` to + attach the driver with reception of broadcast packets enabled. Try to 'ping' + the target system again. Verify that ARP request/reply and ICMP echo + request/reply packets appear on the net. + +- Issue a '``t``' command to send TCP packets to the 'discard' port. Verify + that the packets appear on the network. + +- Issue a '``s``' command to print the network and driver statistics. + +- Verify that you can telnet to ports 24742 and 24743 on the target system from + one or more workstations on your network. + +BOOTP/DHCP operation +==================== + +Set up a BOOTP/DHCP server on the network. Set define ``RTEMS USE_BOOT`` in +``networkconfig.h``. Run the ``netdemo`` test program. Verify that the target +system configures itself from the BOOTP/DHCP server and that all the above +tests succeed. + +Stress Tests +============ + +Once the driver passes the tests described in the previous section it should be +subjected to conditions which exercise it more thoroughly and which test its +error handling routines. + +Giant packets +------------- + +- Recompile the driver with ``MAXIMUM_FRAME_SIZE`` set to a smaller value, + say 514. + +- 'Ping' the driver from another workstation and verify that frames larger than + 514 bytes are correctly rejected. + +- Recompile the driver with ``MAXIMUM_FRAME_SIZE`` restored to 1518. + +Resource Exhaustion +------------------- + +- Edit ``networkconfig.h`` so that the driver is configured with just two + receive and transmit descriptors. + +- Compile and run the ``netdemo`` program. + +- Verify that the program operates properly and that you can still telnet to + both the ports. + +- Display the driver statistics (Console '``s``' command or telnet 'control-G' + character) and verify that: + + #. The number of transmit interrupts is non-zero. This indicates that all + transmit descriptors have been in use at some time. + + #. The number of missed packets is non-zero. This indicates that all receive + descriptors have been in use at some time. + +Cable Faults +------------ + +- Run the ``netdemo`` program. + +- Issue a '``u``' console command to make the target machine transmit a bunch + of UDP packets. + +- While the packets are being transmitted, disconnect and reconnect the network + cable. + +- Display the network statistics and verify that the driver has detected the + loss of carrier. + +- Verify that you can still telnet to both ports on the target machine. + +Throughput +---------- + +Run the ``ttcp`` network benchmark program. Transfer large amounts of data +(100's of megabytes) to and from the target system. + +The procedure for testing throughput from a host to an RTEMS target is as +follows: + + #. Download and start the ttcp program on the Target. + + #. In response to the ``ttcp`` prompt, enter ``-s -r``. The meaning of these + flags is described in the ``ttcp.1`` manual page found in the ``ttcp_orig`` + subdirectory. + + #. On the host run ``ttcp -s -t <<insert the hostname or IP address of the Target here>>`` + +The procedure for testing throughput from an RTEMS target to a Host is as +follows: + + #. On the host run ``ttcp -s -r``. + + #. Download and start the ttcp program on the Target. + + #. In response to the ``ttcp`` prompt, enter ``-s -t <<insert the hostname or + IP address of the Target here>>``. You need to type the IP address of the + host unless your Target is talking to your Domain Name Server. + +To change the number of buffers, the buffer size, etc. you just add the extra +flags to the ``-t`` machine as specified in the ``ttcp.1`` manual page found in +the ``ttcp_orig`` subdirectory. |