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authorAmar Takhar <verm@darkbeer.org>2016-01-16 18:26:00 -0500
committerAmar Takhar <verm@darkbeer.org>2016-05-02 20:51:23 -0400
commitca49bfd73be27cae4a7df00da22e9e7ca5bd8dfa (patch)
treec7a329992aee5b80126af44ff1e418c28424d429
parentd01deadf095d1c6acbd00674f742f6dbfc7bdd53 (diff)
downloadrtems-docs-ca49bfd73be27cae4a7df00da22e9e7ca5bd8dfa.tar.bz2
Split document.
-rw-r--r--networking/command.rst7
-rw-r--r--networking/dec_21140.rst246
-rw-r--r--networking/index.rst52
-rw-r--r--networking/network_servers.rst109
-rw-r--r--networking/network_task_structure.rst38
-rw-r--r--networking/networking_driver.rst325
-rw-r--r--networking/networking_old_reference_only.rst (renamed from networking/networking.rst)0
-rw-r--r--networking/preface.rst44
-rw-r--r--networking/testing_the_driver.rst316
-rw-r--r--networking/using_networking_rtems_app.rst856
10 files changed, 1992 insertions, 1 deletions
diff --git a/networking/command.rst b/networking/command.rst
new file mode 100644
index 0000000..3e23b5e
--- /dev/null
+++ b/networking/command.rst
@@ -0,0 +1,7 @@
+Command and Variable Index
+##########################
+
+There are currently no Command and Variable Index entries.
+
+.. COMMENT: @printindex fn
+
diff --git a/networking/dec_21140.rst b/networking/dec_21140.rst
new file mode 100644
index 0000000..8cc041c
--- /dev/null
+++ b/networking/dec_21140.rst
@@ -0,0 +1,246 @@
+DEC 21140 Driver
+################
+
+DEC 21240 Driver Introduction
+=============================
+
+.. COMMENT: XXX add back in cross reference to list of boards.
+
+One aim of our project is to port RTEMS on a standard PowerPC platform.
+To achieve it, we have chosen a Motorola MCP750 board. This board includes
+an Ethernet controller based on a DEC21140 chip. Because RTEMS has a
+TCP/IP stack, we will
+have to develop the DEC21140 related ethernet driver for the PowerPC port of
+RTEMS. As this controller is able to support 100Mbps network and as there is
+a lot of PCI card using this DEC chip, we have decided to first
+implement this driver on an Intel PC386 target to provide a solution for using
+RTEMS on PC with the 100Mbps network and then to port this code on PowerPC in
+a second phase.
+
+The aim of this document is to give some PCI board generalities and
+to explain the software architecture of the RTEMS driver. Finally, we will see
+what will be done for ChorusOs and Netboot environment .
+
+Document Revision History
+=========================
+
+*Current release*:
+
+- Current applicable release is 1.0.
+
+*Existing releases*:
+
+- 1.0 : Released the 10/02/98. First version of this document.
+
+- 0.1 : First draft of this document
+
+*Planned releases*:
+
+- None planned today.
+
+DEC21140 PCI Board Generalities
+===============================
+
+.. COMMENT: XXX add crossreference to PCI Register Figure
+
+This chapter describes rapidely the PCI interface of this Ethernet controller.
+The board we have chosen for our PC386 implementation is a D-Link DFE-500TX.
+This is a dual-speed 10/100Mbps Ethernet PCI adapter with a DEC21140AF chip.
+Like other PCI devices, this board has a PCI device’s header containing some
+required configuration registers, as shown in the PCI Register Figure.
+By reading
+or writing these registers, a driver can obtain information about the type of
+the board, the interrupt it uses, the mapping of the chip specific registers, ...
+
+On Intel target, the chip specific registers can be accessed via 2
+methods : I/O port access or PCI address mapped access. We have chosen to implement
+the PCI address access to obtain compatible source code to the port the driver
+on a PowerPC target.
+
+.. COMMENT: PCI Device's Configuration Header Space Format
+
+
+.. image:: images/PCIreg.jpg
+
+
+.. COMMENT: XXX add crossreference to PCI Register Figure
+
+On RTEMS, a PCI API exists. We have used it to configure the board. After initializing
+this PCI module via the ``pci_initialize()`` function, we try to detect
+the DEC21140 based ethernet board. This board is characterized by its Vendor
+ID (0x1011) and its Device ID (0x0009). We give these arguments to the``pcib_find_by_deviceid``
+function which returns , if the device is present, a pointer to the configuration
+header space (see PCI Registers Fgure). Once this operation performed,
+the driver
+is able to extract the information it needs to configure the board internal
+registers, like the interrupt line, the base address,... The board internal
+registers will not be detailled here. You can find them in *DIGITAL
+Semiconductor 21140A PCI Fast Ethernet LAN Controller
+- Hardware Reference Manual*.
+
+.. COMMENT: fix citation
+
+RTEMS Driver Software Architecture
+==================================
+
+In this chapter will see the initialization phase, how the controller uses the
+host memory and the 2 threads launched at the initialization time.
+
+Initialization phase
+--------------------
+
+The DEC21140 Ethernet driver keeps the same software architecture than the other
+RTEMS ethernet drivers. The only API the programmer can use is the ``rtems_dec21140_driver_attach````(struct rtems_bsdnet_ifconfig \*config)`` function which
+detects the board and initializes the associated data structure (with registers
+base address, entry points to low-level initialization function,...), if the
+board is found.
+
+Once the attach function executed, the driver initializes the DEC
+chip. Then the driver connects an interrupt handler to the interrupt line driven
+by the Ethernet controller (the only interrupt which will be treated is the
+receive interrupt) and launches 2 threads : a receiver thread and a transmitter
+thread. Then the driver waits for incoming frame to give to the protocol stack
+or outcoming frame to send on the physical link.
+
+Memory Buffer
+-------------
+
+.. COMMENT: XXX add cross reference to Problem
+
+This DEC chip uses the host memory to store the incoming Ethernet frames and
+the descriptor of these frames. We have chosen to use 7 receive buffers and
+1 transmit buffer to optimize memory allocation due to cache and paging problem
+that will be explained in the section *Encountered Problems*.
+
+To reference these buffers to the DEC chip we use a buffer descriptors
+ring. The descriptor structure is defined in the Buffer Descriptor Figure.
+Each descriptor
+can reference one or two memory buffers. We choose to use only one buffer of
+1520 bytes per descriptor.
+
+The difference between a receive and a transmit buffer descriptor
+is located in the status and control bits fields. We do not give details here,
+please refer to the \[DEC21140 Hardware Manual].
+
+.. COMMENT: Buffer Descriptor
+
+
+.. image:: images/recvbd.jpg
+
+
+Receiver Thread
+---------------
+
+This thread is event driven. Each time a DEC PCI board interrupt occurs, the
+handler checks if this is a receive interrupt and send an event “reception”
+to the receiver thread which looks into the entire buffer descriptors ring the
+ones that contain a valid incoming frame (bit OWN=0 means descriptor belongs
+to host processor). Each valid incoming ethernet frame is sent to the protocol
+stack and the buffer descriptor is given back to the DEC board (the host processor
+reset bit OWN, which means descriptor belongs to 21140).
+
+Transmitter Thread
+------------------
+
+This thread is also event driven. Each time an Ethernet frame is put in the
+transmit queue, an event is sent to the transmit thread, which empty the queue
+by sending each outcoming frame. Because we use only one transmit buffer, we
+are sure that the frame is well-sent before sending the next.
+
+Encountered Problems
+====================
+
+On Intel PC386 target, we were faced with a problem of memory cache management.
+Because the DEC chip uses the host memory to store the incoming frame and because
+the DEC21140 configuration registers are mapped into the PCI address space,
+we must ensure that the data read (or written) by the host processor are the
+ones written (or read) by the DEC21140 device in the host memory and not old
+data stored in the cache memory. Therefore, we had to provide a way to manage
+the cache. This module is described in the document *RTEMS
+Cache Management For Intel*. On Intel, the
+memory region cache management is available only if the paging unit is enabled.
+We have used this paging mechanism, with 4Kb page. All the buffers allocated
+to store the incoming or outcoming frames, buffer descriptor and also the PCI
+address space of the DEC board are located in a memory space with cache disable.
+
+Concerning the buffers and their descriptors, we have tried to optimize
+the memory space in term of allocated page. One buffer has 1520 bytes, one descriptor
+has 16 bytes. We have 7 receive buffers and 1 transmit buffer, and for each,
+1 descriptor : (7+1)*(1520+16) = 12288 bytes = 12Kb = 3 entire pages. This
+allows not to lose too much memory or not to disable cache memory for a page
+which contains other data than buffer, which could decrease performance.
+
+ChorusOs DEC Driver
+===================
+
+Because ChorusOs is used in several Canon CRF projects, we must provide such
+a driver on this OS to ensure compatibility between the RTEMS and ChorusOs developments.
+On ChorusOs, a DEC driver source code already exists but only for a PowerPC
+target. We plan to port this code (which uses ChorusOs API) on Intel target.
+This will allow us to have homogeneous developments. Moreover, the port of the
+development performed with ChorusOs environment to RTEMS environment will be
+easier for the developers.
+
+Netboot DEC driver
+==================
+
+We use Netboot tool to load our development from a server to the target via
+an ethernet network. Currently, this tool does not support the DEC board. We
+plan to port the DEC driver for the Netboot tool.
+
+But concerning the port of the DEC driver into Netboot, we are faced
+with a problem : in RTEMS environment, the DEC driver is interrupt or event
+driven, in Netboot environment, it must be used in polling mode. It means that
+we will have to re-write some mechanisms of this driver.
+
+List of Ethernet cards using the DEC chip
+=========================================
+
+Many Ethernet adapter cards use the Tulip chip. Here is a non exhaustive list
+of adapters which support this driver :
+
+- Accton EtherDuo PCI.
+
+- Accton EN1207 All three media types supported.
+
+- Adaptec ANA6911/TX 21140-AC.
+
+- Cogent EM110 21140-A with DP83840 N-Way MII transceiver.
+
+- Cogent EM400 EM100 with 4 21140 100mbps-only ports + PCI Bridge.
+
+- Danpex EN-9400P3.
+
+- D-Link DFE500-Tx 21140-A with DP83840 transceiver.
+
+- Kingston EtherX KNE100TX 21140AE.
+
+- Netgear FX310 TX 10/100 21140AE.
+
+- SMC EtherPower10/100 With DEC21140 and 68836 SYM transceiver.
+
+- SMC EtherPower10/100 With DEC21140-AC and DP83840 MII transceiver.
+ Note: The EtherPower II uses the EPIC chip, which requires a different driver.
+
+- Surecom EP-320X DEC 21140.
+
+- Thomas Conrad TC5048.
+
+- Znyx ZX345 21140-A, usually with the DP83840 N-Way MII transciever. Some ZX345
+ cards made in 1996 have an ICS 1890 transciver instead.
+
+- ZNYX ZX348 Two 21140-A chips using ICS 1890 transcievers and either a 21052
+ or 21152 bridge. Early versions used National 83840 transcievers, but later
+ versions are depopulated ZX346 boards.
+
+- ZNYX ZX351 21140 chip with a Broadcom 100BaseT4 transciever.
+
+Our DEC driver has not been tested with all these cards, only with the D-Link
+DFE500-TX.
+
+- *[DEC21140 Hardware Manual] DIGITAL, *DIGITAL
+ Semiconductor 21140A PCI Fast Ethernet LAN Controller - Hardware
+ Reference Manual**.
+
+- *[99.TA.0021.M.ER]Emmanuel Raguet,*RTEMS Cache Management For Intel**.
+
diff --git a/networking/index.rst b/networking/index.rst
index 67ceead..0489422 100644
--- a/networking/index.rst
+++ b/networking/index.rst
@@ -1 +1,51 @@
-.. include:: networking.rst
+========================
+RTEMS Network Supplement
+========================
+COPYRIGHT © 1988 - 2015.
+
+On-Line Applications Research Corporation (OAR).
+
+The authors have used their best efforts in preparing
+this material. These efforts include the development, research,
+and testing of the theories and programs to determine their
+effectiveness. No warranty of any kind, expressed or implied,
+with regard to the software or the material contained in this
+document is provided. No liability arising out of the
+application or use of any product described in this document is
+assumed. The authors reserve the right to revise this material
+and to make changes from time to time in the content hereof
+without obligation to notify anyone of such revision or changes.
+
+The RTEMS Project is hosted at http://www.rtems.org. Any
+inquiries concerning RTEMS, its related support components, or its
+documentation should be directed to the Community Project hosted athttp://www.rtems.org.
+
+Any inquiries for commercial services including training, support, custom
+development, application development assistance should be directed tohttp://www.rtems.com.
+
+
+Table of Contents
+-----------------
+
+.. toctree::
+
+ preface
+
+
+.. toctree::
+ :maxdepth: 3
+ :numbered:
+
+ preface
+ network_task_structure
+ networking_driver
+ using_networking_rtems_app
+ testing_the_driver
+ network_servers
+ dec_21140
+ command
+
+
+* :ref:`genindex`
+* :ref:`search`
+
diff --git a/networking/network_servers.rst b/networking/network_servers.rst
new file mode 100644
index 0000000..be8a033
--- /dev/null
+++ b/networking/network_servers.rst
@@ -0,0 +1,109 @@
+Network Servers
+###############
+
+RTEMS FTP Daemon
+================
+
+The RTEMS FTPD is a complete file transfer protocol (FTP) daemon
+which can store, retrieve, and manipulate files on the local
+filesystem. In addition, the RTEMS FTPD provides “hooks”
+which are actions performed on received data. Hooks are useful
+in situations where a destination file is not necessarily
+appropriate or in cases when a formal device driver has not yet
+been implemented.
+
+This server was implemented and documented by Jake Janovetz
+(janovetz@tempest.ece.uiuc.edu).
+
+Configuration Parameters
+------------------------
+
+The configuration structure for FTPD is as follows:
+.. code:: c
+
+ struct rtems_ftpd_configuration
+ {
+ rtems_task_priority priority; /* FTPD task priority \*/
+ unsigned long max_hook_filesize; /* Maximum buffersize \*/
+ /* for hooks \*/
+ int port; /* Well-known port \*/
+ struct rtems_ftpd_hook \*hooks; /* List of hooks \*/
+ };
+
+The FTPD task priority is specified with ``priority``. Because
+hooks are not saved as files, the received data is placed in an
+allocated buffer. ``max_hook_filesize`` specifies the maximum
+size of this buffer. Finally, ``hooks`` is a pointer to the
+configured hooks structure.
+
+Initializing FTPD (Starting the daemon)
+---------------------------------------
+
+Starting FTPD is done with a call to ``rtems_initialize_ftpd()``.
+The configuration structure must be provided in the application
+source code. Example hooks structure and configuration structure
+folllow.
+.. code:: c
+
+ struct rtems_ftpd_hook ftp_hooks[] =
+ {
+ {"untar", Untar_FromMemory},
+ {NULL, NULL}
+ };
+ struct rtems_ftpd_configuration rtems_ftpd_configuration =
+ {
+ 40, /* FTPD task priority \*/
+ 512*1024, /* Maximum hook 'file' size \*/
+ 0, /* Use default port \*/
+ ftp_hooks /* Local ftp hooks \*/
+ };
+
+Specifying 0 for the well-known port causes FTPD to use the
+UNIX standard FTPD port (21).
+
+Using Hooks
+-----------
+
+In the example above, one hook was installed. The hook causes
+FTPD to call the function ``Untar_FromMemory`` when the
+user sends data to the file ``untar``. The prototype for
+the ``untar`` hook (and hooks, in general) is:
+.. code:: c
+
+ int Untar_FromMemory(unsigned char \*tar_buf, unsigned long size);
+
+An example FTP transcript which exercises this hook is:
+.. code:: c
+
+ 220 RTEMS FTP server (Version 1.0-JWJ) ready.
+ Name (dcomm0:janovetz): John Galt
+ 230 User logged in.
+ Remote system type is RTEMS.
+ ftp> bin
+ 200 Type set to I.
+ ftp> dir
+ 200 PORT command successful.
+ 150 ASCII data connection for LIST.
+ drwxrwx--x 0 0 268 dev
+ drwxrwx--x 0 0 0 TFTP
+ 226 Transfer complete.
+ ftp> put html.tar untar
+ local: html.tar remote: untar
+ 200 PORT command successful.
+ 150 BINARY data connection.
+ 210 File transferred successfully.
+ 471040 bytes sent in 0.48 secs (9.6e+02 Kbytes/sec)
+ ftp> dir
+ 200 PORT command successful.
+ 150 ASCII data connection for LIST.
+ drwxrwx--x 0 0 268 dev
+ drwxrwx--x 0 0 0 TFTP
+ drwxrwx--x 0 0 3484 public_html
+ 226 Transfer complete.
+ ftp> quit
+ 221 Goodbye.
+
+.. COMMENT: RTEMS Remote Debugger Server Specifications
+
+.. COMMENT: Written by: Emmanuel Raguet <raguet@crf.canon.fr>
+
diff --git a/networking/network_task_structure.rst b/networking/network_task_structure.rst
new file mode 100644
index 0000000..78609dd
--- /dev/null
+++ b/networking/network_task_structure.rst
@@ -0,0 +1,38 @@
+Network Task Structure and Data Flow
+####################################
+
+A schematic diagram of the tasks and message *mbuf* queues in a
+simple RTEMS networking application is shown in the following
+figure:
+
+.. image:: images/networkflow.jpg
+
+
+The transmit task for each network interface is normally blocked waiting
+for a packet to arrive in the transmit queue. Once a packet arrives, the
+transmit task may block waiting for an event from the transmit interrupt
+handler. The transmit interrupt handler sends an RTEMS event to the transmit
+task to indicate that transmit hardware resources have become available.
+
+The receive task for each network interface is normally blocked waiting
+for an event from the receive interrupt handler. When this event is received
+the receive task reads the packet and forwards it to the network stack
+for subsequent processing by the network task.
+
+The network task processes incoming packets and takes care of
+timed operations such as handling TCP timeouts and
+aging and removing routing table entries.
+
+The ‘Network code’ contains routines which may run in the context of
+the user application tasks, the interface receive task or the network task.
+A network semaphore ensures that
+the data structures manipulated by the network code remain consistent.
+
+.. COMMENT: Written by Eric Norum
+
+.. COMMENT: COPYRIGHT (c) 1988-2002.
+
+.. COMMENT: On-Line Applications Research Corporation (OAR).
+
+.. COMMENT: All rights reserved.
+
diff --git a/networking/networking_driver.rst b/networking/networking_driver.rst
new file mode 100644
index 0000000..0f7238b
--- /dev/null
+++ b/networking/networking_driver.rst
@@ -0,0 +1,325 @@
+Networking Driver
+#################
+
+Introduction
+============
+
+This chapter is intended to provide an introduction to the
+procedure for writing RTEMS network device drivers.
+The example code is taken from the ‘Generic 68360’ network device
+driver. The source code for this driver is located in the``c/src/lib/libbsp/m68k/gen68360/network`` directory in the RTEMS
+source code distribution. Having a copy of this driver at
+hand when reading the following notes will help significantly.
+
+Learn about the network device
+==============================
+
+Before starting to write the network driver become completely
+familiar with the programmer’s view of the device.
+The following points list some of the details of the
+device that must be understood before a driver can be written.
+
+- Does the device use DMA to transfer packets to and from
+ memory or does the processor have to
+ copy packets to and from memory on the device?
+
+- If the device uses DMA, is it capable of forming a single
+ outgoing packet from multiple fragments scattered in separate
+ memory buffers?
+
+- If the device uses DMA, is it capable of chaining multiple
+ outgoing packets, or does each outgoing packet require
+ intervention by the driver?
+
+- Does the device automatically pad short frames to the minimum
+ 64 bytes or does the driver have to supply the padding?
+
+- Does the device automatically retry a transmission on detection
+ of a collision?
+
+- If the device uses DMA, is it capable of buffering multiple
+ packets to memory, or does the receiver have to be restarted
+ after the arrival of each packet?
+
+- How are packets that are too short, too long, or received with
+ CRC errors handled? Does the device automatically continue
+ reception or does the driver have to intervene?
+
+- How is the device Ethernet address set? How is the device
+ programmed to accept or reject broadcast and multicast packets?
+
+- What interrupts does the device generate? Does it generate an
+ interrupt for each incoming packet, or only for packets received
+ without error? Does it generate an interrupt for each packet
+ transmitted, or only when the transmit queue is empty? What
+ happens when a transmit error is detected?
+
+In addition, some controllers have specific questions regarding
+board specific configuration. For example, the SONIC Ethernet
+controller has a very configurable data bus interface. It can
+even be configured for sixteen and thirty-two bit data buses. This
+type of information should be obtained from the board vendor.
+
+Understand the network scheduling conventions
+=============================================
+
+When writing code for the driver transmit and receive tasks,
+take care to follow the network scheduling conventions. All tasks
+which are associated with networking share various
+data structures and resources. To ensure the consistency
+of these structures the tasks
+execute only when they hold the network semaphore (``rtems_bsdnet_semaphore``).
+The transmit and receive tasks must abide by this protocol. Be very
+careful to avoid ‘deadly embraces’ with the other network tasks.
+A number of routines are provided to make it easier for the network
+driver code to conform to the network task scheduling conventions.
+
+- ``void rtems_bsdnet_semaphore_release(void)``
+ This function releases the network semaphore.
+ The network driver tasks must call this function immediately before
+ making any blocking RTEMS request.
+
+- ``void rtems_bsdnet_semaphore_obtain(void)``
+ This function obtains the network semaphore.
+ If a network driver task has released the network semaphore to allow other
+ network-related tasks to run while the task blocks, then this function must
+ be called to reobtain the semaphore immediately after the return from the
+ blocking RTEMS request.
+
+- ``rtems_bsdnet_event_receive(rtems_event_set, rtems_option, rtems_interval, rtems_event_set \*)``
+ The network driver task should call this function when it wishes to wait
+ for an event. This function releases the network semaphore,
+ calls ``rtems_event_receive`` to wait for the specified event
+ or events and reobtains the semaphore.
+ The value returned is the value returned by the ``rtems_event_receive``.
+
+Network Driver Makefile
+=======================
+
+Network drivers are considered part of the BSD network package and as such
+are to be compiled with the appropriate flags. This can be accomplished by
+adding ``-D__INSIDE_RTEMS_BSD_TCPIP_STACK__`` to the ``command line``.
+If the driver is inside the RTEMS source tree or is built using the
+RTEMS application Makefiles, then adding the following line accomplishes
+this:
+.. code:: c
+
+ DEFINES += -D__INSIDE_RTEMS_BSD_TCPIP_STACK__
+
+This is equivalent to the following list of definitions. Early versions
+of the RTEMS BSD network stack required that all of these be defined.
+
+.. code:: c
+
+ -D_COMPILING_BSD_KERNEL_ -DKERNEL -DINET -DNFS \\
+ -DDIAGNOSTIC -DBOOTP_COMPAT
+
+Defining these macros tells the network header files that the driver
+is to be compiled with extended visibility into the network stack. This
+is in sharp contrast to applications that simply use the network stack.
+Applications do not require this level of visibility and should stick
+to the portable application level API.
+
+As a direct result of being logically internal to the network stack,
+network drivers use the BSD memory allocation routines This means,
+for example, that malloc takes three arguments. See the SONIC
+device driver (``c/src/lib/libchip/network/sonic.c``) for an example
+of this. Because of this, network drivers should not include``<stdlib.h>``. Doing so will result in conflicting definitions
+of ``malloc()``.
+
+*Application level* code including network servers such as the FTP
+daemon are *not* part of the BSD kernel network code and should not be
+compiled with the BSD network flags. They should include``<stdlib.h>`` and not define the network stack visibility
+macros.
+
+Write the Driver Attach Function
+================================
+
+The driver attach function is responsible for configuring the driver
+and making the connection between the network stack
+and the driver.
+
+Driver attach functions take a pointer to an``rtems_bsdnet_ifconfig`` structure as their only argument.
+and set the driver parameters based on the
+values in this structure. If an entry in the configuration
+structure is zero the attach function chooses an
+appropriate default value for that parameter.
+
+The driver should then set up several fields in the ifnet structure
+in the device-dependent data structure supplied and maintained by the driver:
+
+``ifp->if_softc``
+ Pointer to the device-dependent data. The first entry
+ in the device-dependent data structure must be an ``arpcom``
+ structure.
+
+``ifp->if_name``
+ The name of the device. The network stack uses this string
+ and the device number for device name lookups. The device name should
+ be obtained from the ``name`` entry in the configuration structure.
+
+``ifp->if_unit``
+ The device number. The network stack uses this number and the
+ device name for device name lookups. For example, if``ifp->if_name`` is ‘``scc``’ and ``ifp->if_unit`` is ‘``1``’,
+ the full device name would be ‘``scc1``’. The unit number should be
+ obtained from the ‘name’ entry in the configuration structure.
+
+``ifp->if_mtu``
+ The maximum transmission unit for the device. For Ethernet
+ devices this value should almost always be 1500.
+
+``ifp->if_flags``
+ The device flags. Ethernet devices should set the flags
+ to ``IFF_BROADCAST|IFF_SIMPLEX``, indicating that the
+ device can broadcast packets to multiple destinations
+ and does not receive and transmit at the same time.
+
+``ifp->if_snd.ifq_maxlen``
+ The maximum length of the queue of packets waiting to be
+ sent to the driver. This is normally set to ``ifqmaxlen``.
+
+``ifp->if_init``
+ The address of the driver initialization function.
+
+``ifp->if_start``
+ The address of the driver start function.
+
+``ifp->if_ioctl``
+ The address of the driver ioctl function.
+
+``ifp->if_output``
+ The address of the output function. Ethernet devices
+ should set this to ``ether_output``.
+
+RTEMS provides a function to parse the driver name in the
+configuration structure into a device name and unit number.
+.. code:: c
+
+ int rtems_bsdnet_parse_driver_name (
+ const struct rtems_bsdnet_ifconfig \*config,
+ char \**namep
+ );
+
+The function takes two arguments; a pointer to the configuration
+structure and a pointer to a pointer to a character. The function
+parses the configuration name entry, allocates memory for the driver
+name, places the driver name in this memory, sets the second argument
+to point to the name and returns the unit number.
+On error, a message is printed and -1 is returned.
+
+Once the attach function has set up the above entries it must link the
+driver data structure onto the list of devices by
+calling ``if_attach``. Ethernet devices should then
+call ``ether_ifattach``. Both functions take a pointer to the
+device’s ``ifnet`` structure as their only argument.
+
+The attach function should return a non-zero value to indicate that
+the driver has been successfully configured and attached.
+
+Write the Driver Start Function.
+================================
+
+This function is called each time the network stack wants to start the
+transmitter. This occures whenever the network stack adds a packet
+to a device’s send queue and the ``IFF_OACTIVE`` bit in the
+device’s ``if_flags`` is not set.
+
+For many devices this function need only set the ``IFF_OACTIVE`` bit in the``if_flags`` and send an event to the transmit task
+indicating that a packet is in the driver transmit queue.
+
+Write the Driver Initialization Function.
+=========================================
+
+This function should initialize the device, attach to interrupt handler,
+and start the driver transmit and receive tasks. The function
+.. code:: c
+
+ rtems_id
+ rtems_bsdnet_newproc (char \*name,
+ int stacksize,
+ void(\*entry)(void \*),
+ void \*arg);
+
+should be used to start the driver tasks.
+
+Note that the network stack may call the driver initialization function more
+than once.
+Make sure multiple versions of the receive and transmit tasks are not accidentally
+started.
+
+Write the Driver Transmit Task
+==============================
+
+This task is reponsible for removing packets from the driver send queue and sending them to the device. The task should block waiting for an event from the
+driver start function indicating that packets are waiting to be transmitted.
+When the transmit task has drained the driver send queue the task should clear
+the ``IFF_OACTIVE`` bit in ``if_flags`` and block until another outgoing
+packet is queued.
+
+Write the Driver Receive Task
+=============================
+
+This task should block until a packet arrives from the device. If the
+device is an Ethernet interface the function ``ether_input`` should be called
+to forward the packet to the network stack. The arguments to ``ether_input``
+are a pointer to the interface data structure, a pointer to the ethernet
+header and a pointer to an mbuf containing the packet itself.
+
+Write the Driver Interrupt Handler
+==================================
+
+A typical interrupt handler will do nothing more than the hardware
+manipulation required to acknowledge the interrupt and send an RTEMS event
+to wake up the driver receive or transmit task waiting for the event.
+Network interface interrupt handlers must not make any calls to other
+network routines.
+
+Write the Driver IOCTL Function
+===============================
+
+This function handles ioctl requests directed at the device. The ioctl
+commands which must be handled are:
+
+``SIOCGIFADDR``
+
+``SIOCSIFADDR``
+
+ If the device is an Ethernet interface these
+ commands should be passed on to ``ether_ioctl``.
+
+``SIOCSIFFLAGS``
+
+ This command should be used to start or stop the device,
+ depending on the state of the interface ``IFF_UP`` and``IFF_RUNNING`` bits in ``if_flags``:
+
+ ``IFF_RUNNING``
+
+ Stop the device.
+
+ ``IFF_UP``
+
+ Start the device.
+
+ ``IFF_UP|IFF_RUNNING``
+
+ Stop then start the device.
+
+ ``0``
+
+ Do nothing.
+
+Write the Driver Statistic-Printing Function
+============================================
+
+This function should print the values of any statistic/diagnostic
+counters the network driver may use. The driver ioctl function should call
+the statistic-printing function when the ioctl command is``SIO_RTEMS_SHOW_STATS``.
+
+.. COMMENT: Written by Eric Norum
+
+.. COMMENT: COPYRIGHT (c) 1988-2002.
+
+.. COMMENT: On-Line Applications Research Corporation (OAR).
+
+.. COMMENT: All rights reserved.
+
diff --git a/networking/networking.rst b/networking/networking_old_reference_only.rst
index 604f9a7..604f9a7 100644
--- a/networking/networking.rst
+++ b/networking/networking_old_reference_only.rst
diff --git a/networking/preface.rst b/networking/preface.rst
new file mode 100644
index 0000000..3445189
--- /dev/null
+++ b/networking/preface.rst
@@ -0,0 +1,44 @@
+Preface
+#######
+
+This document describes the RTEMS specific parts of the FreeBSD TCP/IP
+stack. Much of this documentation was written by Eric Norum
+(eric@skatter.usask.ca)
+of the Saskatchewan Accelerator Laboratory
+who also ported the FreeBSD TCP/IP stack to RTEMS.
+
+The following is a list of resources which should be useful in trying
+to understand Ethernet:
+
+- *Charles Spurgeon’s Ethernet Web Site*
+ "This site provides extensive information about Ethernet
+ (IEEE 802.3) local area network (LAN) technology. Including
+ the original 10 Megabit per second (Mbps) system, the 100 Mbps
+ Fast Ethernet system (802.3u), and the Gigabit Ethernet system (802.3z)."
+ The URL is:
+ (http://www.ethermanage.com/ethernet/ethernet.html)
+
+- *TCP/IP Illustrated, Volume 1 : The Protocols* by
+ by W. Richard Stevens (ISBN: 0201633469)
+ This book provides detailed introduction to TCP/IP and includes diagnostic
+ programs which are publicly available.
+
+- *TCP/IP Illustrated, Volume 2 : The Implementation* by W. Richard
+ Stevens and Gary Wright (ISBN: 020163354X)
+ This book focuses on implementation issues regarding TCP/IP. The
+ treat for RTEMS users is that the implementation covered is the BSD
+ stack with most of the source code described in detail.
+
+- *UNIX Network Programming, Volume 1 : 2nd Edition* by W. Richard
+ Stevens (ISBN: 0-13-490012-X)
+ This book describes how to write basic TCP/IP applications, again with primary
+ focus on the BSD stack.
+
+.. COMMENT: Written by Eric Norum
+
+.. COMMENT: COPYRIGHT (c) 1988-2002.
+
+.. COMMENT: On-Line Applications Research Corporation (OAR).
+
+.. COMMENT: All rights reserved.
+
diff --git a/networking/testing_the_driver.rst b/networking/testing_the_driver.rst
new file mode 100644
index 0000000..d71747f
--- /dev/null
+++ b/networking/testing_the_driver.rst
@@ -0,0 +1,316 @@
+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:: c
+
+ 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:: c
+
+ ************ 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:: c
+
+ ************ 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.
+
+.. COMMENT: Text Written by Jake Janovetz
+
+.. COMMENT: COPYRIGHT (c) 1988-2002.
+
+.. COMMENT: On-Line Applications Research Corporation (OAR).
+
+.. COMMENT: All rights reserved.
+
diff --git a/networking/using_networking_rtems_app.rst b/networking/using_networking_rtems_app.rst
new file mode 100644
index 0000000..0778385
--- /dev/null
+++ b/networking/using_networking_rtems_app.rst
@@ -0,0 +1,856 @@
+Using Networking in an RTEMS Application
+########################################
+
+Makefile changes
+================
+
+Including the required managers
+-------------------------------
+
+The FreeBSD networking code requires several RTEMS managers
+in the application:
+.. code:: c
+
+ MANAGERS = io event semaphore
+
+Increasing the size of the heap
+-------------------------------
+
+The networking tasks allocate a lot of memory. For most applications
+the heap should be at least 256 kbytes.
+The amount of memory set aside for the heap can be adjusted by setting
+the ``CFLAGS_LD`` definition as shown below:
+.. code:: c
+
+ CFLAGS_LD += -Wl,--defsym -Wl,HeapSize=0x80000
+
+This sets aside 512 kbytes of memory for the heap.
+
+System Configuration
+====================
+
+The networking tasks allocate some RTEMS objects. These
+must be accounted for in the application configuration table. The following
+lists the requirements.
+
+*TASKS*
+ One network task plus a receive and transmit task for each device.
+
+*SEMAPHORES*
+ One network semaphore plus one syslog mutex semaphore if the application uses
+ openlog/syslog.
+
+*EVENTS*
+ The network stack uses ``RTEMS_EVENT_24`` and ``RTEMS_EVENT_25``.
+ This has no effect on the application configuration, but
+ application tasks which call the network functions should not
+ use these events for other purposes.
+
+Initialization
+==============
+
+Additional include files
+------------------------
+
+The source file which declares the network configuration
+structures and calls the network initialization function must include
+.. code:: c
+
+ #include <rtems/rtems_bsdnet.h>
+
+Network Configuration
+---------------------
+
+The network configuration is specified by declaring
+and initializing the ``rtems_bsdnet_config``
+structure.
+.. code:: c
+
+ struct rtems_bsdnet_config {
+ /*
+ * This entry points to the head of the ifconfig chain.
+ \*/
+ struct rtems_bsdnet_ifconfig \*ifconfig;
+ /*
+ * This entry should be rtems_bsdnet_do_bootp if BOOTP
+ * is being used to configure the network, and NULL
+ * if BOOTP is not being used.
+ \*/
+ void (\*bootp)(void);
+ /*
+ * The remaining items can be initialized to 0, in
+ * which case the default value will be used.
+ \*/
+ rtems_task_priority network_task_priority; /* 100 \*/
+ unsigned long mbuf_bytecount; /* 64 kbytes \*/
+ unsigned long mbuf_cluster_bytecount; /* 128 kbytes \*/
+ char \*hostname; /* BOOTP \*/
+ char \*domainname; /* BOOTP \*/
+ char \*gateway; /* BOOTP \*/
+ char \*log_host; /* BOOTP \*/
+ char \*name_server[3]; /* BOOTP \*/
+ char \*ntp_server[3]; /* BOOTP \*/
+ unsigned long sb_efficiency; /* 2 \*/
+ /* UDP TX: 9216 bytes \*/
+ unsigned long udp_tx_buf_size;
+ /* UDP RX: 40 * (1024 + sizeof(struct sockaddr_in)) \*/
+ unsigned long udp_rx_buf_size;
+ /* TCP TX: 16 * 1024 bytes \*/
+ unsigned long tcp_tx_buf_size;
+ /* TCP TX: 16 * 1024 bytes \*/
+ unsigned long tcp_rx_buf_size;
+ /* Default Network Tasks CPU Affinity \*/
+ #ifdef RTEMS_SMP
+ const cpu_set_t \*network_task_cpuset;
+ size_t network_task_cpuset_size;
+ #endif
+ };
+
+The structure entries are described in the following table.
+If your application uses BOOTP/DHCP to obtain network configuration
+information and if you are happy with the default values described
+below, you need to provide only the first two entries in this structure.
+
+``struct rtems_bsdnet_ifconfig \*ifconfig``
+
+ A pointer to the first configuration structure of the first network
+ device. This structure is described in the following section.
+ You must provide a value for this entry since there is no default value for it.
+
+``void (\*bootp)(void)``
+
+ This entry should be set to ``rtems_bsdnet_do_bootp`` if your
+ application by default uses the BOOTP/DHCP client protocol to obtain
+ network configuration information. It should be set to ``NULL`` if
+ your application does not use BOOTP/DHCP.
+ You can also use ``rtems_bsdnet_do_bootp_rootfs`` to have a set of
+ standard files created with the information return by the BOOTP/DHCP
+ protocol. The IP address is added to :file:`/etc/hosts` with the host
+ name and domain returned. If no host name or domain is returned``me.mydomain`` is used. The BOOTP/DHCP server’s address is also
+ added to :file:`/etc/hosts`. The domain name server listed in the
+ BOOTP/DHCP information are added to :file:`/etc/resolv.conf`. A``search`` record is also added if a domain is returned. The files
+ are created if they do not exist.
+ The default ``rtems_bsdnet_do_bootp`` and``rtems_bsdnet_do_bootp_rootfs`` handlers will loop for-ever
+ waiting for a BOOTP/DHCP server to respond. If an error is detected
+ such as not valid interface or valid hardware address the target will
+ reboot allowing any hardware reset to correct itself.
+ You can provide your own custom handler which allows you to perform
+ an initialization that meets your specific system requirements. For
+ example you could try BOOTP/DHCP then enter a configuration tool if no
+ server is found allowing the user to switch to a static configuration.
+
+``int network_task_priority``
+ The priority at which the network task and network device
+ receive and transmit tasks will run.
+ If a value of 0 is specified the tasks will run at priority 100.
+
+``unsigned long mbuf_bytecount``
+ The number of bytes to allocate from the heap for use as mbufs.
+ If a value of 0 is specified, 64 kbytes will be allocated.
+
+``unsigned long mbuf_cluster_bytecount``
+ The number of bytes to allocate from the heap for use as mbuf clusters.
+ If a value of 0 is specified, 128 kbytes will be allocated.
+
+``char \*hostname``
+ The host name of the system.
+ If this, or any of the following, entries are ``NULL`` the value
+ may be obtained from a BOOTP/DHCP server.
+
+``char \*domainname``
+ The name of the Internet domain to which the system belongs.
+
+``char \*gateway``
+ The Internet host number of the network gateway machine,
+ specified in ’dotted decimal’ (``129.128.4.1``) form.
+
+``char \*log_host``
+ The Internet host number of the machine to which ``syslog`` messages
+ will be sent.
+
+``char \*name_server[3]``
+ The Internet host numbers of up to three machines to be used as
+ Internet Domain Name Servers.
+
+``char \*ntp_server[3]``
+ The Internet host numbers of up to three machines to be used as
+ Network Time Protocol (NTP) Servers.
+
+``unsigned long sb_efficiency``
+ This is the first of five configuration parameters related to
+ the amount of memory each socket may consume for buffers. The
+ TCP/IP stack reserves buffers (e.g. mbufs) for each open socket. The
+ TCP/IP stack has different limits for the transmit and receive
+ buffers associated with each TCP and UDP socket. By tuning these
+ parameters, the application developer can make trade-offs between
+ memory consumption and performance. The default parameters favor
+ performance over memory consumption. Seehttp://www.rtems.org/ml/rtems-users/2004/february/msg00200.html
+ for more details but note that after the RTEMS 4.8 release series,
+ the sb_efficiency default was changed from ``8`` to ``2``.
+ The user should also be aware of the ``SO_SNDBUF`` and ``SO_RCVBUF``
+ IO control operations. These can be used to specify the
+ send and receive buffer sizes for a specific socket. There
+ is no standard IO control to change the ``sb_efficiency`` factor.
+ The ``sb_efficiency`` parameter is a buffering factor used
+ in the implementation of the TCP/IP stack. The default is ``2``
+ which indicates double buffering. When allocating memory for each
+ socket, this number is multiplied by the buffer sizes for that socket.
+
+``unsigned long udp_tx_buf_size``
+
+ This configuration parameter specifies the maximum amount of
+ buffer memory which may be used for UDP sockets to transmit
+ with. The default size is 9216 bytes which corresponds to
+ the maximum datagram size.
+
+``unsigned long udp_rx_buf_size``
+
+ This configuration parameter specifies the maximum amount of
+ buffer memory which may be used for UDP sockets to receive
+ into. The default size is the following length in bytes:
+
+ .. code:: c
+
+ 40 * (1024 + sizeof(struct sockaddr_in)
+
+``unsigned long tcp_tx_buf_size``
+
+ This configuration parameter specifies the maximum amount of
+ buffer memory which may be used for TCP sockets to transmit
+ with. The default size is sixteen kilobytes.
+
+``unsigned long tcp_rx_buf_size``
+
+ This configuration parameter specifies the maximum amount of
+ buffer memory which may be used for TCP sockets to receive
+ into. The default size is sixteen kilobytes.
+
+``const cpu_set_t \*network_task_cpuset``
+
+ This configuration parameter specifies the CPU affinity of the
+ network task. If set to ``0`` the network task can be scheduled on
+ any CPU. Only available in SMP configurations.
+
+``size_t network_task_cpuset_size``
+
+ This configuration parameter specifies the size of the``network_task_cpuset`` used. Only available in SMP configurations.
+
+In addition, the following fields in the ``rtems_bsdnet_ifconfig``
+are of interest.
+
+*int port*
+ The I/O port number (ex: 0x240) on which the external Ethernet
+ can be accessed.
+
+*int irno*
+ The interrupt number of the external Ethernet controller.
+
+*int bpar*
+ The address of the shared memory on the external Ethernet controller.
+
+Network device configuration
+----------------------------
+
+Network devices are specified and configured by declaring and initializing a``struct rtems_bsdnet_ifconfig`` structure for each network device.
+
+The structure entries are described in the following table. An application
+which uses a single network interface, gets network configuration information
+from a BOOTP/DHCP server, and uses the default values for all driver
+parameters needs to initialize only the first two entries in the
+structure.
+
+``char \*name``
+ The full name of the network device. This name consists of the
+ driver name and the unit number (e.g. ``"scc1"``).
+ The ``bsp.h`` include file usually defines RTEMS_BSP_NETWORK_DRIVER_NAME as
+ the name of the primary (or only) network driver.
+
+``int (\*attach)(struct rtems_bsdnet_ifconfig \*conf)``
+ The address of the driver ``attach`` function. The network
+ initialization function calls this function to configure the driver and
+ attach it to the network stack.
+ The ``bsp.h`` include file usually defines RTEMS_BSP_NETWORK_DRIVER_ATTACH as
+ the name of the attach function of the primary (or only) network driver.
+
+``struct rtems_bsdnet_ifconfig \*next``
+ A pointer to the network device configuration structure for the next network
+ interface, or ``NULL`` if this is the configuration structure of the
+ last network interface.
+
+``char \*ip_address``
+ The Internet address of the device,
+ specified in ‘dotted decimal’ (``129.128.4.2``) form, or ``NULL``
+ if the device configuration information is being obtained from a
+ BOOTP/DHCP server.
+
+``char \*ip_netmask``
+ The Internet inetwork mask of the device,
+ specified in ‘dotted decimal’ (``255.255.255.0``) form, or ``NULL``
+ if the device configuration information is being obtained from a
+ BOOTP/DHCP server.
+
+``void \*hardware_address``
+ The hardware address of the device, or ``NULL`` if the driver is
+ to obtain the hardware address in some other way (usually by reading
+ it from the device or from the bootstrap ROM).
+
+``int ignore_broadcast``
+ Zero if the device is to accept broadcast packets, non-zero if the device
+ is to ignore broadcast packets.
+
+``int mtu``
+ The maximum transmission unit of the device, or zero if the driver
+ is to choose a default value (typically 1500 for Ethernet devices).
+
+``int rbuf_count``
+ The number of receive buffers to use, or zero if the driver is to
+ choose a default value
+
+``int xbuf_count``
+ The number of transmit buffers to use, or zero if the driver is to
+ choose a default value
+ Keep in mind that some network devices may use 4 or more
+ transmit descriptors for a single transmit buffer.
+
+A complete network configuration specification can be as simple as the one
+shown in the following example.
+This configuration uses a single network interface, gets
+network configuration information
+from a BOOTP/DHCP server, and uses the default values for all driver
+parameters.
+.. code:: c
+
+ static struct rtems_bsdnet_ifconfig netdriver_config = {
+ RTEMS_BSP_NETWORK_DRIVER_NAME,
+ RTEMS_BSP_NETWORK_DRIVER_ATTACH
+ };
+ struct rtems_bsdnet_config rtems_bsdnet_config = {
+ &netdriver_config,
+ rtems_bsdnet_do_bootp,
+ };
+
+Network initialization
+----------------------
+
+The networking tasks must be started before any network I/O operations
+can be performed. This is done by calling:
+
+.. code:: c
+
+ rtems_bsdnet_initialize_network ();
+
+This function is declared in ``rtems/rtems_bsdnet.h``.
+t returns 0 on success and -1 on failure with an error code
+in ``errno``. It is not possible to undo the effects of
+a partial initialization, though, so the function can be
+called only once irregardless of the return code. Consequently,
+if the condition for the failure can be corrected, the
+system must be reset to permit another network initialization
+attempt.
+
+Application Programming Interface
+=================================
+
+The RTEMS network package provides almost a complete set of BSD network
+services. The network functions work like their BSD counterparts
+with the following exceptions:
+
+- A given socket can be read or written by only one task at a time.
+
+- The ``select`` function only works for file descriptors associated
+ with sockets.
+
+- You must call ``openlog`` before calling any of the ``syslog`` functions.
+
+- *Some of the network functions are not thread-safe.*
+ For example the following functions return a pointer to a static
+ buffer which remains valid only until the next call:
+
+ ``gethostbyaddr``
+
+ ``gethostbyname``
+
+ ``inet_ntoa``
+
+ (``inet_ntop`` is thread-safe, though).
+
+- The RTEMS network package gathers statistics.
+
+- Addition of a mechanism to "tap onto" an interface
+ and monitor every packet received and transmitted.
+
+- Addition of ``SO_SNDWAKEUP`` and ``SO_RCVWAKEUP`` socket options.
+
+Some of the new features are discussed in more detail in the following
+sections.
+
+Network Statistics
+------------------
+
+There are a number of functions to print statistics gathered by
+the network stack.
+These function are declared in ``rtems/rtems_bsdnet.h``.
+
+``rtems_bsdnet_show_if_stats``
+ Display statistics gathered by network interfaces.
+
+``rtems_bsdnet_show_ip_stats``
+ Display IP packet statistics.
+
+``rtems_bsdnet_show_icmp_stats``
+ Display ICMP packet statistics.
+
+``rtems_bsdnet_show_tcp_stats``
+ Display TCP packet statistics.
+
+``rtems_bsdnet_show_udp_stats``
+ Display UDP packet statistics.
+
+``rtems_bsdnet_show_mbuf_stats``
+ Display mbuf statistics.
+
+``rtems_bsdnet_show_inet_routes``
+ Display the routing table.
+
+Tapping Into an Interface
+-------------------------
+
+RTEMS add two new ioctls to the BSD networking code:
+SIOCSIFTAP and SIOCGIFTAP. These may be used to set and get a*tap function*. The tap function will be called for every
+Ethernet packet received by the interface.
+
+These are called like other interface ioctls, such as SIOCSIFADDR.
+When setting the tap function with SIOCSIFTAP, set the ifr_tap field
+of the ifreq struct to the tap function. When retrieving the tap
+function with SIOCGIFTAP, the current tap function will be returned in
+the ifr_tap field. To stop tapping packets, call SIOCSIFTAP with a
+ifr_tap field of 0.
+
+The tap function is called like this:
+.. code:: c
+
+ int tap (struct ifnet \*, struct ether_header \*, struct mbuf \*)
+
+The tap function should return 1 if the packet was fully handled, in
+which case the caller will simply discard the mbuf. The tap function
+should return 0 if the packet should be passed up to the higher
+networking layers.
+
+The tap function is called with the network semaphore locked. It must
+not make any calls on the application levels of the networking level
+itself. It is safe to call other non-networking RTEMS functions.
+
+Socket Options
+--------------
+
+RTEMS adds two new ``SOL_SOCKET`` level options for ``setsockopt`` and``getsockopt``: ``SO_SNDWAKEUP`` and ``SO_RCVWAKEUP``. For both, the
+option value should point to a sockwakeup structure. The sockwakeup
+structure has the following fields:
+.. code:: c
+
+ void (\*sw_pfn) (struct socket \*, caddr_t);
+ caddr_t sw_arg;
+
+These options are used to set a callback function to be called when, for
+example, there is
+data available from the socket (``SO_RCVWAKEUP``) and when there is space
+available to accept data written to the socket (``SO_SNDWAKEUP``).
+
+If ``setsockopt`` is called with the ``SO_RCVWAKEUP`` option, and the``sw_pfn`` field is not zero, then when there is data
+available to be read from
+the socket, the function pointed to by the ``sw_pfn`` field will be
+called. A pointer to the socket structure will be passed as the first
+argument to the function. The ``sw_arg`` field set by the``SO_RCVWAKEUP`` call will be passed as the second argument to the function.
+
+If ``setsockopt`` is called with the ``SO_SNDWAKEUP``
+function, and the ``sw_pfn`` field is not zero, then when
+there is space available to accept data written to the socket,
+the function pointed to by the ``sw_pfn`` field
+will be called. The arguments passed to the function will be as with``SO_SNDWAKEUP``.
+
+When the function is called, the network semaphore will be locked and
+the callback function runs in the context of the networking task.
+The function must be careful not to call any networking functions. It
+is OK to call an RTEMS function; for example, it is OK to send an
+RTEMS event.
+
+The purpose of these callback functions is to permit a more efficient
+alternative to the select call when dealing with a large number of
+sockets.
+
+The callbacks are called by the same criteria that the select
+function uses for indicating "ready" sockets. In Stevens *Unix
+Network Programming* on page 153-154 in the section "Under what Conditions
+Is a Descriptor Ready?" you will find the definitive list of conditions
+for readable and writable that also determine when the functions are
+called.
+
+When the number of received bytes equals or exceeds the socket receive
+buffer "low water mark" (default 1 byte) you get a readable callback. If
+there are 100 bytes in the receive buffer and you only read 1, you will
+not immediately get another callback. However, you will get another
+callback after you read the remaining 99 bytes and at least 1 more byte
+arrives. Using a non-blocking socket you should probably read until it
+produces error EWOULDBLOCK and then allow the readable callback to tell
+you when more data has arrived. (Condition 1.a.)
+
+For sending, when the socket is connected and the free space becomes at
+or above the "low water mark" for the send buffer (default 4096 bytes)
+you will receive a writable callback. You don’t get continuous callbacks
+if you don’t write anything. Using a non-blocking write socket, you can
+then call write until it returns a value less than the amount of data
+requested to be sent or it produces error EWOULDBLOCK (indicating buffer
+full and no longer writable). When this happens you can
+try the write again, but it is often better to go do other things and
+let the writable callback tell you when space is available to send
+again. You only get a writable callback when the free space transitions
+to above the "low water mark" and not every time you
+write to a non-full send buffer. (Condition 2.a.)
+
+The remaining conditions enumerated by Stevens handle the fact that
+sockets become readable and/or writable when connects, disconnects and
+errors occur, not just when data is received or sent. For example, when
+a server "listening" socket becomes readable it indicates that a client
+has connected and accept can be called without blocking, not that
+network data was received (Condition 1.c).
+
+Adding an IP Alias
+------------------
+
+The following code snippet adds an IP alias:
+.. code:: c
+
+ void addAlias(const char \*pName, const char \*pAddr, const char \*pMask)
+ {
+ struct ifaliasreq aliasreq;
+ struct sockaddr_in \*in;
+ /* initialize alias request \*/
+ memset(&aliasreq, 0, sizeof(aliasreq));
+ sprintf(aliasreq.ifra_name, pName);
+ /* initialize alias address \*/
+ in = (struct sockaddr_in \*)&aliasreq.ifra_addr;
+ in->sin_family = AF_INET;
+ in->sin_len = sizeof(aliasreq.ifra_addr);
+ in->sin_addr.s_addr = inet_addr(pAddr);
+ /* initialize alias mask \*/
+ in = (struct sockaddr_in \*)&aliasreq.ifra_mask;
+ in->sin_family = AF_INET;
+ in->sin_len = sizeof(aliasreq.ifra_mask);
+ in->sin_addr.s_addr = inet_addr(pMask);
+ /* call to setup the alias \*/
+ rtems_bsdnet_ifconfig(pName, SIOCAIFADDR, &aliasreq);
+ }
+
+Thanks to `Mike Seirs <mailto:mikes@poliac.com>`_ for this example
+code.
+
+Adding a Default Route
+----------------------
+
+The function provided in this section is functionally equivalent to
+the command ``route add default gw yyy.yyy.yyy.yyy``:
+.. code:: c
+
+ void mon_ifconfig(int argc, char \*argv[], unsigned32 command_arg,
+ bool verbose)
+ {
+ struct sockaddr_in ipaddr;
+ struct sockaddr_in dstaddr;
+ struct sockaddr_in netmask;
+ struct sockaddr_in broadcast;
+ char \*iface;
+ int f_ip = 0;
+ int f_ptp = 0;
+ int f_netmask = 0;
+ int f_up = 0;
+ int f_down = 0;
+ int f_bcast = 0;
+ int cur_idx;
+ int rc;
+ int flags;
+ bzero((void*) &ipaddr, sizeof(ipaddr));
+ bzero((void*) &dstaddr, sizeof(dstaddr));
+ bzero((void*) &netmask, sizeof(netmask));
+ bzero((void*) &broadcast, sizeof(broadcast));
+ ipaddr.sin_len = sizeof(ipaddr);
+ ipaddr.sin_family = AF_INET;
+ dstaddr.sin_len = sizeof(dstaddr);
+ dstaddr.sin_family = AF_INET;
+ netmask.sin_len = sizeof(netmask);
+ netmask.sin_family = AF_INET;
+ broadcast.sin_len = sizeof(broadcast);
+ broadcast.sin_family = AF_INET;
+ cur_idx = 0;
+ if (argc <= 1) {
+ /* display all interfaces \*/
+ iface = NULL;
+ cur_idx += 1;
+ } else {
+ iface = argv[1];
+ if (isdigit(\*argv[2])) {
+ if (inet_pton(AF_INET, argv[2], &ipaddr.sin_addr) < 0) {
+ printf("bad ip address: %s\\n", argv[2]);
+ return;
+ }
+ f_ip = 1;
+ cur_idx += 3;
+ } else {
+ cur_idx += 2;
+ }
+ }
+ if ((f_down !=0) && (f_ip != 0)) {
+ f_up = 1;
+ }
+ while(argc > cur_idx) {
+ if (strcmp(argv[cur_idx], "up") == 0) {
+ f_up = 1;
+ if (f_down != 0) {
+ printf("Can't make interface up and down\\n");
+ }
+ } else if(strcmp(argv[cur_idx], "down") == 0) {
+ f_down = 1;
+ if (f_up != 0) {
+ printf("Can't make interface up and down\\n");
+ }
+ } else if(strcmp(argv[cur_idx], "netmask") == 0) {
+ if ((cur_idx + 1) >= argc) {
+ printf("No netmask address\\n");
+ return;
+ }
+ if (inet_pton(AF_INET, argv[cur_idx+1], &netmask.sin_addr) < 0) {
+ printf("bad netmask: %s\\n", argv[cur_idx]);
+ return;
+ }
+ f_netmask = 1;
+ cur_idx += 1;
+ } else if(strcmp(argv[cur_idx], "broadcast") == 0) {
+ if ((cur_idx + 1) >= argc) {
+ printf("No broadcast address\\n");
+ return;
+ }
+ if (inet_pton(AF_INET, argv[cur_idx+1], &broadcast.sin_addr) < 0) {
+ printf("bad broadcast: %s\\n", argv[cur_idx]);
+ return;
+ }
+ f_bcast = 1;
+ cur_idx += 1;
+ } else if(strcmp(argv[cur_idx], "pointopoint") == 0) {
+ if ((cur_idx + 1) >= argc) {
+ printf("No pointopoint address\\n");
+ return;
+ }
+ if (inet_pton(AF_INET, argv[cur_idx+1], &dstaddr.sin_addr) < 0) {
+ printf("bad pointopoint: %s\\n", argv[cur_idx]);
+ return;
+ }
+ f_ptp = 1;
+ cur_idx += 1;
+ } else {
+ printf("Bad parameter: %s\\n", argv[cur_idx]);
+ return;
+ }
+ cur_idx += 1;
+ }
+ printf("ifconfig ");
+ if (iface != NULL) {
+ printf("%s ", iface);
+ if (f_ip != 0) {
+ char str[256];
+ inet_ntop(AF_INET, &ipaddr.sin_addr, str, 256);
+ printf("%s ", str);
+ }
+ if (f_netmask != 0) {
+ char str[256];
+ inet_ntop(AF_INET, &netmask.sin_addr, str, 256);
+ printf("netmask %s ", str);
+ }
+ if (f_bcast != 0) {
+ char str[256];
+ inet_ntop(AF_INET, &broadcast.sin_addr, str, 256);
+ printf("broadcast %s ", str);
+ }
+ if (f_ptp != 0) {
+ char str[256];
+ inet_ntop(AF_INET, &dstaddr.sin_addr, str, 256);
+ printf("pointopoint %s ", str);
+ }
+ if (f_up != 0) {
+ printf("up\\n");
+ } else if (f_down != 0) {
+ printf("down\\n");
+ } else {
+ printf("\\n");
+ }
+ }
+ if ((iface == NULL) \|| ((f_ip == 0) && (f_down == 0) && (f_up == 0))) {
+ rtems_bsdnet_show_if_stats();
+ return;
+ }
+ flags = 0;
+ if (f_netmask) {
+ rc = rtems_bsdnet_ifconfig(iface, SIOCSIFNETMASK, &netmask);
+ if (rc < 0) {
+ printf("Could not set netmask: %s\\n", strerror(errno));
+ return;
+ }
+ }
+ if (f_bcast) {
+ rc = rtems_bsdnet_ifconfig(iface, SIOCSIFBRDADDR, &broadcast);
+ if (rc < 0) {
+ printf("Could not set broadcast: %s\\n", strerror(errno));
+ return;
+ }
+ }
+ if (f_ptp) {
+ rc = rtems_bsdnet_ifconfig(iface, SIOCSIFDSTADDR, &dstaddr);
+ if (rc < 0) {
+ printf("Could not set destination address: %s\\n", strerror(errno));
+ return;
+ }
+ flags \|= IFF_POINTOPOINT;
+ }
+ /* This must come _after_ setting the netmask, broadcast addresses \*/
+ if (f_ip) {
+ rc = rtems_bsdnet_ifconfig(iface, SIOCSIFADDR, &ipaddr);
+ if (rc < 0) {
+ printf("Could not set IP address: %s\\n", strerror(errno));
+ return;
+ }
+ }
+ if (f_up != 0) {
+ flags \|= IFF_UP;
+ }
+ if (f_down != 0) {
+ printf("Warning: taking interfaces down is not supported\\n");
+ }
+ rc = rtems_bsdnet_ifconfig(iface, SIOCSIFFLAGS, &flags);
+ if (rc < 0) {
+ printf("Could not set interface flags: %s\\n", strerror(errno));
+ return;
+ }
+ }
+ void mon_route(int argc, char \*argv[], unsigned32 command_arg,
+ bool verbose)
+ {
+ int cmd;
+ struct sockaddr_in dst;
+ struct sockaddr_in gw;
+ struct sockaddr_in netmask;
+ int f_host;
+ int f_gw = 0;
+ int cur_idx;
+ int flags;
+ int rc;
+ memset(&dst, 0, sizeof(dst));
+ memset(&gw, 0, sizeof(gw));
+ memset(&netmask, 0, sizeof(netmask));
+ dst.sin_len = sizeof(dst);
+ dst.sin_family = AF_INET;
+ dst.sin_addr.s_addr = inet_addr("0.0.0.0");
+ gw.sin_len = sizeof(gw);
+ gw.sin_family = AF_INET;
+ gw.sin_addr.s_addr = inet_addr("0.0.0.0");
+ netmask.sin_len = sizeof(netmask);
+ netmask.sin_family = AF_INET;
+ netmask.sin_addr.s_addr = inet_addr("255.255.255.0");
+ if (argc < 2) {
+ rtems_bsdnet_show_inet_routes();
+ return;
+ }
+ if (strcmp(argv[1], "add") == 0) {
+ cmd = RTM_ADD;
+ } else if (strcmp(argv[1], "del") == 0) {
+ cmd = RTM_DELETE;
+ } else {
+ printf("invalid command: %s\\n", argv[1]);
+ printf("\\tit should be 'add' or 'del'\\n");
+ return;
+ }
+ if (argc < 3) {
+ printf("not enough arguments\\n");
+ return;
+ }
+ if (strcmp(argv[2], "-host") == 0) {
+ f_host = 1;
+ } else if (strcmp(argv[2], "-net") == 0) {
+ f_host = 0;
+ } else {
+ printf("Invalid type: %s\\n", argv[1]);
+ printf("\\tit should be '-host' or '-net'\\n");
+ return;
+ }
+ if (argc < 4) {
+ printf("not enough arguments\\n");
+ return;
+ }
+ inet_pton(AF_INET, argv[3], &dst.sin_addr);
+ cur_idx = 4;
+ while(cur_idx < argc) {
+ if (strcmp(argv[cur_idx], "gw") == 0) {
+ if ((cur_idx +1) >= argc) {
+ printf("no gateway address\\n");
+ return;
+ }
+ f_gw = 1;
+ inet_pton(AF_INET, argv[cur_idx + 1], &gw.sin_addr);
+ cur_idx += 1;
+ } else if(strcmp(argv[cur_idx], "netmask") == 0) {
+ if ((cur_idx +1) >= argc) {
+ printf("no netmask address\\n");
+ return;
+ }
+ f_gw = 1;
+ inet_pton(AF_INET, argv[cur_idx + 1], &netmask.sin_addr);
+ cur_idx += 1;
+ } else {
+ printf("Unknown argument\\n");
+ return;
+ }
+ cur_idx += 1;
+ }
+ flags = RTF_STATIC;
+ if (f_gw != 0) {
+ flags \|= RTF_GATEWAY;
+ }
+ if (f_host != 0) {
+ flags \|= RTF_HOST;
+ }
+ rc = rtems_bsdnet_rtrequest(cmd, &dst, &gw, &netmask, flags, NULL);
+ if (rc < 0) {
+ printf("Error adding route\\n");
+ }
+ }
+
+Thanks to `Jay Monkman <mailto:jtm@smoothmsmoothie.com>`_ for this example
+code.
+
+Time Synchronization Using NTP
+------------------------------
+
+.. code:: c
+
+ int rtems_bsdnet_synchronize_ntp (int interval, rtems_task_priority priority);
+
+If the interval argument is 0 the routine synchronizes the RTEMS time-of-day
+clock with the first NTP server in the rtems_bsdnet_ntpserve array and
+returns. The priority argument is ignored.
+
+If the interval argument is greater than 0, the routine also starts an
+RTEMS task at the specified priority and polls the NTP server every
+‘interval’ seconds. NOTE: This mode of operation has not yet been
+implemented.
+
+On successful synchronization of the RTEMS time-of-day clock the routine
+returns 0. If an error occurs a message is printed and the routine returns -1
+with an error code in errno.
+There is no timeout – if there is no response from an NTP server the
+routine will wait forever.
+
+.. COMMENT: Written by Eric Norum
+
+.. COMMENT: COPYRIGHT (c) 1988-2002.
+
+.. COMMENT: On-Line Applications Research Corporation (OAR).
+
+.. COMMENT: All rights reserved.
+