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<task id="GUID-45E1953A-DEFB-5E48-AC96-443A3234F913" xml:lang="en"><title>Retrieving

an IP Network Parameters Tutorial</title><shortdesc>How to retrieve IP network parameters from a DHCP server configured

network connection. </shortdesc><prolog><metadata><keywords/></metadata></prolog><taskbody>

<context id="GUID-C919A1D1-FE46-4D60-B20B-75D919404AB6"><p> The high level steps to retrieve an IP network parameters are

as  follows: </p></context>

<steps id="GUID-A25ECF43-E64D-5DB2-B783-924BFA48F4A0">

<step id="GUID-5851EFBA-6976-55A6-A736-2480750951B6"><cmd>Open a socket using <codeph>RSocketServer</codeph> object. </cmd>

</step>

<step id="GUID-0E0A1640-7A99-587F-B70A-2057C6E3C201"><cmd>Create a connection

using <xref href="GUID-BED8A733-2ED7-31AD-A911-C1F4707C67FD.dita"><apiname>RConnection</apiname></xref> function. </cmd>

</step>

<step id="GUID-A248BB53-9180-5777-93C4-2B964C15FFC3"><cmd>Start the connection

using <xref href="GUID-BED8A733-2ED7-31AD-A911-C1F4707C67FD.dita"><apiname>RConnection</apiname></xref> with necessary preferences. </cmd>

<info>For example, enable DHCP server. The active connection is configured

by the DHCP server. </info>

</step>

<step id="GUID-796FB8CD-D4CD-54CE-93E0-90E8AD2F1B10"><cmd>To retrieve the

active network connection parameters, Call the <xref href="GUID-BED8A733-2ED7-31AD-A911-C1F4707C67FD.dita#GUID-BED8A733-2ED7-31AD-A911-C1F4707C67FD/GUID-9F820CF9-1D4F-3452-983B-E0C694D6783A"><apiname>RConnection::Ioctl()</apiname></xref> function

by passing the relevant arguments. </cmd>

</step>

<step id="GUID-926BD804-72F9-55F3-8569-4385FAB28989"><cmd>The <xref href="GUID-BED8A733-2ED7-31AD-A911-C1F4707C67FD.dita#GUID-BED8A733-2ED7-31AD-A911-C1F4707C67FD/GUID-9F820CF9-1D4F-3452-983B-E0C694D6783A"><apiname>RConnection::Ioctl()</apiname></xref> function

returns the necessary parameters. </cmd>

<info><p><note> Multiple option codes can be queried to a DHCP server using

the &lt;api-item&gt;TDhcpRawOptionMultipleDataPckg&lt;/api-item&gt; object.</note></p><p> The

advantages of retrieving multiple parameters are: </p><ul>

<li><p>It reduces IPC calls between application and the DHCP daemon. </p></li>

<li><p>It reduces the messages exchanged between the DHCP daemon and the DHCP

server. </p></li>

</ul></info>

</step>

</steps>

<example><title> Retrieve IP Network Parameters example</title> <p>The following

is an example code for how to retrieve IP network parameters: </p> <codeblock id="GUID-39A702E4-A746-5BFA-A00E-AD34DBE2AD97" xml:space="preserve">

//create a socket connection  

RSocketServ esock; 

TInt err = eSock.Connect();

...

//handle the error

...

RConnection aConnection;   //create a RConnection 

err = aConnection.Open(esock);

...

//start the connection with necessary preferences

...

err = aConnection.Start(iConnPrefs);

//Retrieve the TFTP server address

TRequestStatus status1;

TTftpServerAddrBuf tftpserveraddr; // Buffer to store TFTP server address

tftpserveraddr().index = 0;

aConnection.Ioctl(KCOLConfiguration, KConnGetTftpServerAddr, status1, &tftpserveraddress);

User::WaitForRequest(status1);

...

//Retrieve the host name of the TFTP server

TRequestStatus status2;

TBuf<256> tftpname; //buffer to store TFTP server name

aConnection.Ioctl(KCOLConfiguration, KConnGetTftpServerName, status2, &tftpname);

User::WaitForRequest(status2);

...

//Retrieve SiAddr field from a DHCP header

TRequestStatus status3;

TConnectionAddrBuf addr;

addr().iAddressFamily = IpAddressFamily();

aConnection.Ioctl(KCOLConfiguration, KConnGetDhcpHdrSiaddr, status3, &addr);

...

//Retrieve SName field from a DHCP header

TRequestStatus status4;

TBuf<64> snamebuf;

aConnection.Ioctl(KCOLConfiguration, KConnGetDhcpHdrSname, status4, &snamebuf);

...

//Retrieve the active IP address

TRequestStatus status5;

TConnectionAddress actaddr;

actaddr().iAddressFamily = IpAddressFamily();

aConnection.Ioctl(KCOLConfiguration, KConnGetCurrentAddr, status5, &actaddr); 

...

//Retrieve multiple parameters

Multiple opcodes can be queried to a DHCP server using the 

TDhcpRawOptionMultipleDataPckg object. 

TBuf8<300> rawbuf;

rawbuf.FillZ(300);   //buffer must be large enough for all returned options values

TDhcpRawOptionMultipleDataPckg pckg1(rawbuf);

pckg1.AddRawOptionCodeL(KTFtpServerAddress);    //option 150 

pckg1.AddRawOptionCodeL(KGeoConfCivicOption);   //option 99

pckg1.AddRawOptionCodeL(KTFtpServerName);  // option 66

TRequestStatus status6;    

// Get raw option data for ip4

aConnection.Ioctl(KCOLConfiguration, KConnDhcpGetMultipleParams, status6, &rawbuf);

User::WaitForRequest(status);

...

</codeblock> </example>

</taskbody><related-links>

<link href="GUID-69B46D92-8D07-5B42-B603-3F725977AA4A.dita"><linktext>DHCP</linktext>

</link>