dhcpslib.html

Vxworks API操作系统和驱动程序设计API。压缩的HTML文件

The storage routine is installed by a call to the <b><a href="./dhcpsLib.html#dhcpsLeaseHookAdd">dhcpsLeaseHookAdd</a>(&nbsp;)</b> routine
The manual pages for <b><a href="./dhcpsLib.html#dhcpsLeaseHookAdd">dhcpsLeaseHookAdd</a>(&nbsp;)</b> describe the parameters and required 
operation of the storage routine.
<p>
</blockquote><h4>SECONDARY INTERFACE</h4><blockquote><p>
In addition to the hard-coded entries, address entries may be added after the 
server has started by calling the following routine:
<pre>    STATUS dhcpsLeaseEntryAdd (char *name, char *start, char *end, char *config);
</pre>
The parameters specify an entry name, starting and ending values for a block 
of IP addresses, and additional configuration information in the same format 
as shown above for the hard-coded entries.  Each parameter must be formatted 
as a NULL-terminated string. 
<p>
The <b>DHCPS_ADDRESS_HOOK</b> constant specifies the name of a storage routine, used 
to preserve address entries added after startup, which has the following 
prototype:
<pre>    STATUS dhcpsAddressStorageHook (int op,
                                    char *name, char *start, char *end, 
                                    char *params);
</pre>
The storage routine is installed with the <b><a href="./dhcpsLib.html#dhcpsAddressHookAdd">dhcpsAddressHookAdd</a>(&nbsp;)</b> routine, and 
is fully described in the manual pages for that function.
<p>
</blockquote><h4>OPTIONAL INTERFACE</h4><blockquote><p>
The DHCP server can also receive messages forwarded from different subnets
by a relay agent.  To provide addresses to clients on different subnets, the
appropriate relay agents must be listed in the provided table in <b>usrNetwork.c</b>. 
A sample configuration is:
<pre>    DHCPS_RELAY_DESC dhcpsRelayTbl [] =
        {
        {"90.11.46.75", "90.11.46.0"}
        };
</pre>
Each entry in the table specifies the address of a relay agent that will 
transmit the request and the corresponding subnet number.  To issue leases
successfully, the address pool must also contain IP addresses for the 
monitored subnets.
<p>
The following table allows a DHCP server to act as a relay agent in 
addition to its default function of processing messages.  It consists of 
a list of IP addresses.
<pre>    DHCP_TARGET_DESC dhcpTargetTbl [] =
         {
         {"90.11.43.2"},
         {"90.11.44.1"}
         };
</pre>
Each IP address in this list receives a copy of any client messages
generated on the subnets monitored by the server.
<p>
</blockquote><h4>INCLUDE FILES</h4><blockquote><p>
<b>dhcpsLib.h</b>
<p>
</blockquote><h4>SEE ALSO</h4><blockquote><p>
RFC 1541, RFC 1533

<hr>
<a name="dhcpsInit"></a>
<p align=right>
<a href="rtnIndex.htm"><i>OS Libraries :  Routines</i></a></p>

</blockquote><h1>dhcpsInit(&nbsp;)</h1> <blockquote></a></blockquote><h4>NAME</h4><blockquote>  
<p><strong>dhcpsInit(&nbsp;)</strong> - set up the DHCP server parameters and data structures</p>

</blockquote><h4>SYNOPSIS</h4><blockquote><p>
<pre>STATUS dhcpsInit
    (
    DHCPS_CFG_PARAMS * pDhcpsCfg /* configuration parameters */
    )
</pre>

</blockquote><h4>DESCRIPTION</h4><blockquote><p>
This routine creates the necessary data structures, builds the
server address pool, retrieves any lease or address information from 
permanent storage through the user-provided hooks, and initializes the 
network interfaces for monitoring.  It is called at system startup if 
<b>INCLUDE_DHCPS</b> is defined at the time the VxWorks image is built.
<p>
The <i>maxSize</i> parameter specifies the maximum length supported for any
DHCP message, including the UDP and IP headers and the largest link
level header for all supported devices. The smallest valid value is
576 bytes, corresponding to the minimum IP datagram a host must accept.
Larger values will allow the server to handle longer DHCP messages.
<p>
</blockquote><h4>RETURNS</h4><blockquote><p>
OK, or ERROR if could not initialize.
</blockquote><h4>SEE ALSO</h4><blockquote><p>
<b><a href="./dhcpsLib.html#top">dhcpsLib</a></b>

<hr>
<a name="dhcpsLeaseEntryAdd"></a>
<p align=right>
<a href="rtnIndex.htm"><i>OS Libraries :  Routines</i></a></p>

</blockquote><h1>dhcpsLeaseEntryAdd(&nbsp;)</h1> <blockquote></a></blockquote><h4>NAME</h4><blockquote>  
<p><strong>dhcpsLeaseEntryAdd(&nbsp;)</strong> - add another entry to the address pool</p>

</blockquote><h4>SYNOPSIS</h4><blockquote><p>
<pre>STATUS dhcpsLeaseEntryAdd
    (
    char * pName,             /* name of lease entry */
    char * pStartIp,          /* first IP address to assign */
    char * pEndIp,            /* last IP address in assignment range */
    char * pParams            /* formatted string of lease parameters */
    )
</pre>

</blockquote><h4>DESCRIPTION</h4><blockquote><p>
This routine allows the user to add new entries to the address pool without
rebuilding the VxWorks image.  The routine requires a unique entry name of up
to eight characters, starting and ending IP addresses, and a colon-separated 
list of parameters.  Possible values for the parameters are listed in the 
reference entry for <b><a href="./dhcpsLib.html#top">dhcpsLib</a></b>.  The parameters also determine the type of 
lease, which the server uses to determine priority when assigning lease 
addresses.  For examples of the possible lease types, see the reference 
entry for <b><a href="./dhcpsLib.html#top">dhcpsLib</a></b>.
<p>
</blockquote><h4>RETURNS</h4><blockquote><p>
OK if entry read successfully, or ERROR otherwise.
<p>
</blockquote><h4>ERRNO</h4><blockquote><p>
N/A
</blockquote><h4>SEE ALSO</h4><blockquote><p>
<b><a href="./dhcpsLib.html#top">dhcpsLib</a></b>

<hr>
<a name="dhcpsLeaseHookAdd"></a>
<p align=right>
<a href="rtnIndex.htm"><i>OS Libraries :  Routines</i></a></p>

</blockquote><h1>dhcpsLeaseHookAdd(&nbsp;)</h1> <blockquote></a></blockquote><h4>NAME</h4><blockquote>  
<p><strong>dhcpsLeaseHookAdd(&nbsp;)</strong> - assign a permanent lease storage hook for the server</p>

</blockquote><h4>SYNOPSIS</h4><blockquote><p>
<pre>STATUS dhcpsLeaseHookAdd
    (
    FUNCPTR pCacheHookRtn     /* routine to store/retrieve lease records */
    )
</pre>

</blockquote><h4>DESCRIPTION</h4><blockquote><p>
This routine allows the server to access some form of permanent storage
that it can use to store current lease information across restarts.  The 
only argument to <b><a href="./dhcpsLib.html#dhcpsLeaseHookAdd">dhcpsLeaseHookAdd</a>(&nbsp;)</b> is a pointer to a storage routine 
with the following interface: 
<pre>    STATUS dhcpsStorageHook (int op, char *buffer, int datalen);
</pre>
The first parameter of the storage routine specifies one of the following 
operations: 
<p>
&nbsp;&nbsp;&nbsp;&nbsp;<b>DHCPS_STORAGE_START</b><br>
&nbsp;&nbsp;&nbsp;&nbsp;<b>DHCPS_STORAGE_READ</b><br>
&nbsp;&nbsp;&nbsp;&nbsp;<b>DHCPS_STORAGE_WRITE</b><br>
&nbsp;&nbsp;&nbsp;&nbsp;<b>DHCPS_STORAGE_STOP</b><br>
&nbsp;&nbsp;&nbsp;&nbsp;<b>DHCPS_STORAGE_CLEAR</b>
<p>
In response to START, the storage routine should prepare to return data or 
overwrite data provided by earlier WRITEs.  For a WRITE the storage routine 
must save the contents of the buffer to permanent storage.  For a READ, the 
storage routine should copy data previously stored into the provided buffer 
as a NULL-terminated string in FIFO order.  For a CLEAR, the storage routine 
should discard currently stored data.  After a CLEAR, the READ operation
must return ERROR until additional data is stored.  For a STOP, the storage 
routine must handle cleanup.  After a STOP, READ and WRITE operations must
return error until a START is received.  Each of these operations must 
return OK if successful, or ERROR otherwise.
<p>
Before the server is initialized, VxWorks automatically calls 
<b><a href="./dhcpsLib.html#dhcpsLeaseHookAdd">dhcpsLeaseHookAdd</a>(&nbsp;)</b>, passing in the routine name defined by <b>DHCPS_LEASE_HOOK</b>.
<p>
</blockquote><h4>RETURNS</h4><blockquote><p>
OK, or ERROR if routine is NULL.
<p>
</blockquote><h4>ERRNO</h4><blockquote><p>
N/A
</blockquote><h4>SEE ALSO</h4><blockquote><p>
<b><a href="./dhcpsLib.html#top">dhcpsLib</a></b>

<hr>
<a name="dhcpsAddressHookAdd"></a>
<p align=right>
<a href="rtnIndex.htm"><i>OS Libraries :  Routines</i></a></p>

</blockquote><h1>dhcpsAddressHookAdd(&nbsp;)</h1> <blockquote></a></blockquote><h4>NAME</h4><blockquote>  
<p><strong>dhcpsAddressHookAdd(&nbsp;)</strong> - assign a permanent address storage hook for the server</p>

</blockquote><h4>SYNOPSIS</h4><blockquote><p>
<pre>STATUS dhcpsAddressHookAdd
    (
    FUNCPTR pCacheHookRtn     /* routine to store/retrieve lease entries */
    )
</pre>

</blockquote><h4>DESCRIPTION</h4><blockquote><p>
This routine allows the server to access some form of permanent storage
to preserve additional address entries across restarts.  This routine is
not required, but leases using unsaved addresses are not renewed.  The 
only argument provided is the name of a function with the following interface:
<pre>    STATUS dhcpsAddressStorageHook (int op,
                                    char *name, char *start, char *end, 
                                    char *params);
</pre>
The first parameter of this storage routine specifies one of the following 
operations: 
<p>
&nbsp;&nbsp;&nbsp;&nbsp;<b>DHCPS_STORAGE_START</b><br>
&nbsp;&nbsp;&nbsp;&nbsp;<b>DHCPS_STORAGE_READ</b><br>
&nbsp;&nbsp;&nbsp;&nbsp;<b>DHCPS_STORAGE_WRITE</b><br>
&nbsp;&nbsp;&nbsp;&nbsp;<b>DHCPS_STORAGE_STOP</b>&nbsp;
<p>
In response to a START, the storage routine should prepare to return
data or overwrite data provided by earlier WRITE operations.  For a 
WRITE, the storage routine must save the contents of the four buffers 
to permanent storage.  Those buffers contain the NULL-terminated 
strings received by the <b><a href="./dhcpsLib.html#dhcpsLeaseEntryAdd">dhcpsLeaseEntryAdd</a>(&nbsp;)</b> routine.  For a READ, the
storage routine should copy previously stored data (as NULL-terminated 
strings) into the provided buffers in the order received by earlier WRITE
operations.  For a STOP, the storage routine should do any necessary cleanup. 
After a STOP, the storage routine should return an ERROR for all operations 
except START.  However, the STOP operation does not normally occur since
the server only deliberately exits following an unrecoverable error.  This
storage routine must not rely on that operation to handle READ, WRITE, or
new START attempts.
<p>
The storage routine should return OK if successful, ERROR otherwise.
<p>
Note that, unlike the lease storage routine, there is no CLEAR operation.
<p>
Before the server is initialized, VxWorks calls this routine automatically 
passing in the function named in <b>DHCPS_ADDRESS_HOOK</b>.
<p>
</blockquote><h4>RETURNS</h4><blockquote><p>
OK, or ERROR if function pointer is NULL.
<p>
</blockquote><h4>ERRNO</h4><blockquote><p>
N/A
</blockquote><h4>SEE ALSO</h4><blockquote><p>
<b><a href="./dhcpsLib.html#top">dhcpsLib</a></b>

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