/*

* Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

*

*/

#include <sys/cdefs.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <sys/sockio.h>

#include <stdapis/net/if.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <errno.h>

/*

 * Return All Interface Names and Indexes

 *

 *    The if_nameindex structure holds the information about a single

 *    interface and is defined as a result of including the <net/if.h>

 *    header.

 *

 *       struct if_nameindex {

 *         unsigned int   if_index;

 *         char          *if_name;

 *       };

 *

 *    The final function returns an array of if_nameindex structures, one

 *    structure per interface.

 *

 *       struct if_nameindex  *if_nameindex(void);

 *

 *    The end of the array of structures is indicated by a structure with

 *    an if_index of 0 and an if_name of NULL.  The function returns a NULL

 *    pointer upon an error, and would set errno to the appropriate value.

 *

 *    The memory used for this array of structures along with the interface

 *    names pointed to by the if_name members is obtained dynamically.

 *    This memory is freed by the next function.

 *

 * Free Memory

 *

 *    The following function frees the dynamic memory that was allocated by

 *    if_nameindex().

 *

 *        #include <stdapis/net/if.h>

 *

 *        void  if_freenameindex(struct if_nameindex *ptr);

 *

 *    The argument to this function must be a pointer that was returned by

 *    if_nameindex().

 */

int getifinfo(struct if_nameindex **pif);

EXPORT_C struct if_nameindex *if_nameindex(void)

	{

	struct if_nameindex *ifni;

	// Memory allocation for ifni is in getifaddrs() function

	if (getifinfo(&ifni) < 0)

		{

		errno = ENXIO;

		return(NULL);

		}

	return ifni;

	}

EXPORT_C void if_freenameindex(struct if_nameindex *ptr)

	{	

	free(ptr);

	}

int getifinfo(struct if_nameindex **pif)

	{

	char *buf;

	struct ifconf ifc;

	struct ifreq *ifr;	

	int ret;

	int index;

	struct if_nameindex *data;

	char *names;

	int sock;

    int namelength = 0;

	int count = 0;//IAP count

	if(pif == NULL)	

		{

		return (-1);

		}

	*pif = NULL;

	if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)

		{

		return (-1);

		}

	//for calculating the number of access points

	ret =  ioctl(sock, SIOCGIFNUM, &count);

	if (ret < 0)

	    {

	    close(sock);

	    return (-1);

	    }

	//allocate only if ioctl()is successfull

	buf = (char *)malloc(count*sizeof(struct ifreq));

	if (buf == NULL)

		{

		close(sock);

		return (-1);

		}

	ifc.ifc_buf = buf;

	ifc.ifc_len = count*sizeof(struct ifreq);

	//this ioctl obtains the ifnet(access point) details

	ret =  ioctl(sock, SIOCGIFCONF, (char *)&ifc);

	close(sock);

	if (ret < 0)

		{

		free(buf);

		return (-1);

		}

	ifr = ifc.ifc_req;

	if (ifr == NULL || count == 0)

		{

		free(buf);

		return (-1);

		}

	// Calulate the memory requirement of interface names		

	for (index = 0; index < count; index++)

		{

		namelength += strlen(ifr->ifr_name);

		namelength++; // +1 for null character

		ifr++;

		}

    /*

     * Next, allocate a chunk of memory, use the first part

     * for the array of structures, and the last part for

     * the strings.

     */

	*pif = (struct if_nameindex*)malloc( ( (count + 1) * sizeof(struct if_nameindex) ) + namelength);

	if (*pif == NULL)

		{

		free(buf);

		return (-1);

		}

	data = *pif;

	names = (char*)(*pif + count + 1);

	// Traverse the ifc, copy index and name

	ifr = ifc.ifc_req;

	for (index = 0; index < count; index++)

		{

		data->if_index = ifr->ifr_index;

		data->if_name = names;

		strcpy(data->if_name, ifr->ifr_name);

		names = names + strlen(ifr->ifr_name) + 1; // +1 for null character

		ifr++;

		data++;

		}

	// Finally, don't forget to terminate the array.	

	data->if_index = 0;

	data->if_name = NULL;

	free(buf);

	return (0);

	}