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<PART id="tcpip-openbsd">
<TITLE>OpenBSD TCP/IP Stack port for eCos</TITLE>
<PARTINTRO>
<PARA>	  <productname>TCP/IP Networking for eCos</productname>
          now provides a complete
	  TCP/IP networking stack, which is derived from a
	  stable release of OpenBSD. The networking support is
	  fully featured and well tested within the eCos environment.
	</PARA>
</PARTINTRO>

<CHAPTER id="tcpip-openbsd-networking-stack-features">
<TITLE>Networking Stack Features</TITLE>
<SECT1 id="tcpip-openbsd-tcpip-features">
<TITLE>Introduction</TITLE>
<PARA>Since this networking package is based on BSD code, it is
very complete and robust.  The eCos implementation includes support
for the following protocols:   </PARA>
<itemizedlist>
<LISTITEM><PARA>IPv4</para></listitem>
<LISTITEM><PARA>UDP</para></listitem>
<LISTITEM><PARA>TCP</para></listitem>
<LISTITEM><PARA>ICMP</para></listitem>
<LISTITEM><PARA>raw packet interface</para></listitem>
</itemizedlist>
<PARA>Along with support for the above mentioned protocols, the OpenBSD
stack also supports ethernet bridging.
</PARA>
<PARA>The following additional features are also present in the package,
	but are not supported:</PARA>
<itemizedlist>
<LISTITEM><PARA>Berkeley Packet Filter   </PARA></LISTITEM>
<LISTITEM><PARA>Multi-cast and uni-cast support, including multi-cast
routing   </PARA></LISTITEM>
<LISTITEM><PARA>IPv6 </PARA></LISTITEM>
      </itemizedlist>
</SECT1>
</CHAPTER>
<CHAPTER id="tcpip-openbsd-stack-port">
<TITLE>OpenBSD TCP/IP stack port</TITLE>
<PARA>This document describes how to get started with the OpenBSD
TCP/IP network stack. </PARA>
<SECT1 id="tcpip-openbsd-tcpip-targets">
<TITLE>Targets</TITLE>
<PARA>A number of ethernet devices may be supported. The default configuration
supports two instances of the interface by default,
and you will need to write your own driver instantiation code,
and supplemental startup and initialization code,
if you should add additional ones.</PARA>
<PARA>The target for your board will normally be supplied with an
ethernet driver, in which case including the network stack and
generic ethernet driver package to your build will automatically
enable usage of the ethernet device driver.
If your target is not supplied with an ethernet
driver, you will need to use loopback (see
<xref linkend="net-common-loopback-tests">).</PARA>
</SECT1>
<SECT1 id="tcpip-openbsd-building-the-network-stack">
<TITLE><!--<conditionaltext>-->Building the Network Stack</TITLE>
<PARA>Using the <EMPHASIS>Build-&gt;Packages</EMPHASIS> dialog,
add the packages &ldquo;Networking&rdquo;,
&ldquo;OpenBSD TCP/IP Stack&rdquo;
and &ldquo;Common Ethernet Support&rdquo;
to your configuration.  Their package names
are CYGPKG_NET, CYGPKG_NET_OPENBSD_STACK and CYGPKG_NET_ETH_DRIVERS
respectively.</PARA>
<para>A short-cut way to do this is by
using the &ldquo;net&rdquo; <emphasis>template</emphasis>
if it is available for your platform.</para>
<PARA>The platform-specific ethernet device driver for your platform
will be added as part of the target selection (in the
<EMPHASIS>Build-&gt;Templates</EMPHASIS> &ldquo;Hardware&rdquo; item),
along with the 
PCI I/O subsystem (if relevent) and the appropriate serial device driver.
</para><para>
For example, the PowerPC MBX target selection adds the package
PKG_NET_QUICC_ETH_DRIVERS,
and the Cirrus Logic EDB7xxx target selection adds the package
CYGPKG_NET_EDB7XXX_ETH_DRIVERS.
After this, eCos and its tests can be built exactly as usual.</PARA>
<NOTE>
<PARA>By default, most of the network tests are not built.  This
is because some of them require manual intervention, i.e. they are
to be run &ldquo;by hand&rdquo;, and are not suitable for
automated testing.  To build the full set of network tests, set
the configuration option CYGPKG_NET_BUILD_TESTS &ldquo;Build
networking tests (demo programs)&rdquo; within &ldquo;Networking
support build options&rdquo;.</PARA>
</NOTE>
</SECT1>
<SECT1 id="tcpip-openbsd-building-the-bridge-code">
<TITLE>Inclusion of bridge code</TITLE>

<PARA>The OpenBSD stack does not by default result in the inclusion of
the bridge code. To include bridging functionality the CDL option
CYGPKG_NET_BRIDGE must be enable . It is also possible to enable more
than one concurrent bridge. The number of bridges active in a device
is configured by the CDL option CYGNUM_NET_BRIDGES, which has a
default value of 1.</PARA>

<PARA>The default behavior of a bridge is to operate without the
spanning tree protocol. When devices are operated in this default mode
it must be ensured the network topology is loop-free. Any loops will
cause broadcast storms and general mayhem on the network.  Including
spanning tree code during the build process will allow the bridge to
communicate with other bridges. They can then detect such loops and by
disabling selected interfaces break the loop. To enable spanning tree enable
the CDL option CYGPKG_NET_BRIDGE_STP_CODE.</PARA>
</SECT1>
</CHAPTER>
<CHAPTER id="tcpip-openbsd-tcpip-apis">
<TITLE>APIs</TITLE>
<SECT1 id="tcpip-openbsd-standard-networking-api">
<TITLE>Standard networking</TITLE>
<PARA>The APIs for the standard networking calls such as
<FUNCTION>socket()</FUNCTION>, <FUNCTION>recv()</FUNCTION> and so on, are
in header files relative to the top-level
include directory, within the standard subdirectories as conventionally
found in <FILENAME>/usr/include</FILENAME>.  For example:
<PROGRAMLISTING>
 install/include/arpa/tftp.h
 install/include/netinet/tcpip.h
 install/include/sys/socket.h
 install/include/sys/socketvar.h
 install/include/sys/sockio.h
</PROGRAMLISTING>
</PARA><PARA>
<filename>network.h</filename> at the top level
defines various extensions, for example the API
<function>init_all_network_interfaces(void)</function>
described
above.  We advise including <filename>network.h</filename> whether
you use these features or not.</PARA>
<PARA>In general, using the networking code may require definition
of two symbols: _KERNEL and __ECOS.  _KERNEL
is not normally required; __ECOS is normally required.
So add this to your compile lines for files which use the network
stack:</PARA>
<PROGRAMLISTING>	-D__ECOS</PROGRAMLISTING>
<PARA>To expand a little, it&rsquo;s like this because this is
a port of a standard distribution external to Red Hat.  One goal
is to perturb the sources as little as possible, so that upgrading
and maintenance from the external distribution is simplified.  The __ECOS
symbol marks out Red Hat&rsquo;s additions in making the port.
The _KERNEL symbol is traditional UNIX practice: it distinguishes
a compilation which is to be linked into the kernel from one which
is part of an application.  eCos applications are fully linked,
so this distinction does not apply.  _KERNEL can however
be used to control the visibility of the internals of the stack,
so depending on what features your application uses, it may or may
not be necessary.</PARA>
<PARA>The include file <filename>network.h</filename> undefines _KERNEL
unconditionally, to provide an application-like compilation environment.
If you were writing code which, for example,
enumerates the stack&rsquo;s internal
structures, that is a kernel-like compilation environment, so you
would need to define _KERNEL (in addition to __ECOS)
and avoid including <filename>network.h</filename>.</PARA>
</SECT1>
<SECT1 id="tcpip-openbsd-enhanced-select">
<TITLE>Enhanced Select()</TITLE>
<PARA>The network stack supports an extension to the standard select
semantics which allows all threads that are waiting to be restarted
even if the select conditions are not satisfied.</PARA>
<PARA>The standard select() API:  </PARA>
<PROGRAMLISTING>int  
<function>select</function>(int nfd,
       fd_set &ast;in, fd_set &ast;out, fd_set &ast;ex,
       struct timeval &ast;tv); </PROGRAMLISTING>
<PARA>does not support the restart.</PARA>
<PARA>The additional API:  </PARA>
<PROGRAMLISTING>int  
<function>cyg_select_with_abort</function>(int nfd,
       fd_set &ast;in, fd_set &ast;out, fd_set &ast;ex,
       struct timeval &ast;tv)
</PROGRAMLISTING>
<PARA>behaves exactly as select() with the additional feature that
a call to</PARA>
<PROGRAMLISTING>
void <function>cyg_select_abort</function>(void)
</PROGRAMLISTING>
<PARA>will cause all threads waiting in any
<function>cyg_select_with_abort()</function> call
to cease waiting and continue execution.</PARA>
</SECT1>
&net-tcpip-openbsd-manpages-netintro-sgml
&net-tcpip-openbsd-manpages-bridge-sgml
&net-tcpip-openbsd-manpages-stp-sgml
</CHAPTER>
</PART>
