URL
https://opencores.org/ocsvn/openrisc_me/openrisc_me/trunk
Subversion Repositories openrisc_me
[/] [openrisc/] [trunk/] [rtos/] [ecos-2.0/] [doc/] [html/] [ref/] [fileio-sockets.html] - Rev 441
Go to most recent revision | Compare with Previous | Blame | View Log
<!-- Copyright (C) 2003 Red Hat, Inc. -->
<!-- This material may be distributed only subject to the terms -->
<!-- and conditions set forth in the Open Publication License, v1.0 -->
<!-- or later (the latest version is presently available at -->
<!-- http://www.opencontent.org/openpub/). -->
<!-- Distribution of the work or derivative of the work in any -->
<!-- standard (paper) book form is prohibited unless prior -->
<!-- permission is obtained from the copyright holder. -->
<HTML
><HEAD
><TITLE
>Sockets</TITLE
><meta name="MSSmartTagsPreventParsing" content="TRUE">
<META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+
"><LINK
REL="HOME"
TITLE="eCos Reference Manual"
HREF="ecos-ref.html"><LINK
REL="UP"
TITLE="File System Support Infrastructure"
HREF="fileio.html"><LINK
REL="PREVIOUS"
TITLE="Initialization and Mounting"
HREF="fileio-mounting.html"><LINK
REL="NEXT"
TITLE="Select"
HREF="fileio-select.html"></HEAD
><BODY
CLASS="CHAPTER"
BGCOLOR="#FFFFFF"
TEXT="#000000"
LINK="#0000FF"
VLINK="#840084"
ALINK="#0000FF"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
>eCos Reference Manual</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="bottom"
><A
HREF="fileio-mounting.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="fileio-select.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="CHAPTER"
><H1
><A
NAME="FILEIO-SOCKETS">Chapter 26. Sockets</H1
><P
>If a network stack is present, then the FILEIO infrastructure also
provides access to the standard BSD socket calls.</P
><P
>The netstack table contains entries which describe the network
protocol stacks that are in the system image. Each resident stack
should export an entry to this table using the
<TT
CLASS="LITERAL"
>NSTAB_ENTRY()</TT
> macro.</P
><P
>Each table entry has the following structure:</P
><TABLE
BORDER="5"
BGCOLOR="#E0E0F0"
WIDTH="70%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>struct cyg_nstab_entry
{
cyg_bool valid; // true if stack initialized
cyg_uint32 syncmode; // synchronization protocol
char *name; // stack name
char *devname; // hardware device name
CYG_ADDRWORD data; // private data value
int (*init)( cyg_nstab_entry *nste );
int (*socket)( cyg_nstab_entry *nste, int domain, int type,
int protocol, cyg_file *file );
};</PRE
></TD
></TR
></TABLE
><P
>This table is analogous to a combination of the filesystem and mount
tables.</P
><P
>The <TT
CLASS="STRUCTFIELD"
><I
>valid</I
></TT
> field is set
<TT
CLASS="LITERAL"
>true</TT
> if the stack's <TT
CLASS="FUNCTION"
>init()</TT
>
function returned successfully and the
<TT
CLASS="STRUCTFIELD"
><I
>syncmode</I
></TT
> field contains the
<TT
CLASS="LITERAL"
>CYG_SYNCMODE_SOCK_*</TT
> bits described above.</P
><P
>The <TT
CLASS="STRUCTFIELD"
><I
>name</I
></TT
> field contains the name of the
protocol stack.</P
><P
>The <TT
CLASS="STRUCTFIELD"
><I
>devname</I
></TT
> field names the device that the stack is using. This may
reference a device under "/dev", or may be a name that is only
meaningful to the stack itself.</P
><P
>The <TT
CLASS="FUNCTION"
>init()</TT
> function pointer is called during
system initialization to start the protocol stack running. If it
returns non-zero the <TT
CLASS="STRUCTFIELD"
><I
>valid</I
></TT
> field is set
false and the stack will be ignored subsequently.</P
><P
>The <TT
CLASS="FUNCTION"
>socket()</TT
> function is called to attempt to create a socket in the
stack. When the <TT
CLASS="FUNCTION"
>socket()</TT
> API function is called the netstack table is
scanned and for each valid entry the <TT
CLASS="FUNCTION"
>socket()</TT
>
function pointer is called. If
this returns non-zero then the scan continues to the next valid stack,
or terminates with an error if the end of the table is reached.</P
><P
>The result of a successful socket call is an initialized file object
with the <TT
CLASS="STRUCTFIELD"
><I
>f_xops</I
></TT
> field pointing to the
following structure:</P
><TABLE
BORDER="5"
BGCOLOR="#E0E0F0"
WIDTH="70%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>struct cyg_sock_ops
{
int (*bind) ( cyg_file *fp, const sockaddr *sa, socklen_t len );
int (*connect) ( cyg_file *fp, const sockaddr *sa, socklen_t len );
int (*accept) ( cyg_file *fp, cyg_file *new_fp,
struct sockaddr *name, socklen_t *anamelen );
int (*listen) ( cyg_file *fp, int len );
int (*getname) ( cyg_file *fp, sockaddr *sa, socklen_t *len, int peer );
int (*shutdown) ( cyg_file *fp, int flags );
int (*getsockopt)( cyg_file *fp, int level, int optname,
void *optval, socklen_t *optlen);
int (*setsockopt)( cyg_file *fp, int level, int optname,
const void *optval, socklen_t optlen);
int (*sendmsg) ( cyg_file *fp, const struct msghdr *m,
int flags, ssize_t *retsize );
int (*recvmsg) ( cyg_file *fp, struct msghdr *m,
socklen_t *namelen, ssize_t *retsize );
};</PRE
></TD
></TR
></TABLE
><P
>It should be obvious from the names of these functions which API calls
they provide support for. The <TT
CLASS="FUNCTION"
>getname()</TT
> function
pointer provides support for both <TT
CLASS="FUNCTION"
>getsockname()</TT
>
and <TT
CLASS="FUNCTION"
>getpeername()</TT
> while the
<TT
CLASS="FUNCTION"
>sendmsg()</TT
> and <TT
CLASS="FUNCTION"
>recvmsg()</TT
>
function pointers provide support for <TT
CLASS="FUNCTION"
>send()</TT
>,
<TT
CLASS="FUNCTION"
>sendto()</TT
>, <TT
CLASS="FUNCTION"
>sendmsg()</TT
>,
<TT
CLASS="FUNCTION"
>recv()</TT
>, <TT
CLASS="FUNCTION"
>recvfrom()</TT
> and
<TT
CLASS="FUNCTION"
>recvmsg()</TT
> as appropriate.</P
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="fileio-mounting.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="ecos-ref.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="fileio-select.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>Initialization and Mounting</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="fileio.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Select</TD
></TR
></TABLE
></DIV
></BODY
></HTML
> Go to most recent revision | Compare with Previous | Blame | View Log