/*
 * Licensed under the GNU General Public License version 2 with exceptions. See
 * LICENSE file in the project root for full license information
 */

#include <sys/ioctl.h>
#include <net/if.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "oshw.h"

/**
 * Host to Network byte order (i.e. to big endian).
 *
 * Note that Ethercat uses little endian byte order, except for the Ethernet
 * header which is big endian as usual.
 */
uint16 oshw_htons(uint16 host)
{
   uint16 network = htons (host);
   return network;
}

/**
 * Network (i.e. big endian) to Host byte order.
 *
 * Note that Ethercat uses little endian byte order, except for the Ethernet
 * header which is big endian as usual.
 */
uint16 oshw_ntohs(uint16 network)
{
   uint16 host = ntohs (network);
   return host;
}

/** Create list over available network adapters.
 * @return First element in linked list of adapters
 */
ec_adaptert * oshw_find_adapters(void)
{
   int i;
   int string_len;
   struct if_nameindex *ids;
   ec_adaptert * adapter;
   ec_adaptert * prev_adapter;
   ec_adaptert * ret_adapter = NULL;


   /* Iterate all devices and create a local copy holding the name and
    * decsription.
    */

   ids = if_nameindex ();
   for(i = 0; ids[i].if_index != 0; i++)
   {
      adapter = (ec_adaptert *)malloc(sizeof(ec_adaptert));
      /* If we got more than one adapter save link list pointer to previous
       * adapter.
       * Else save as pointer to return.
       */
      if (i)
      {
         prev_adapter->next = adapter;
      }
      else
      {
         ret_adapter = adapter;
      }

      /* fetch description and name, in linux we use the same on both */
      adapter->next = NULL;

      if (ids[i].if_name)
      {
          string_len = strlen(ids[i].if_name);
          if (string_len > (EC_MAXLEN_ADAPTERNAME - 1))
          {
             string_len = EC_MAXLEN_ADAPTERNAME - 1;
          }
          strncpy(adapter->name, ids[i].if_name,string_len);
          adapter->name[string_len] = '\0';
          strncpy(adapter->desc, ids[i].if_name,string_len);
          adapter->desc[string_len] = '\0';
      }
      else
      {
         adapter->name[0] = '\0';
         adapter->desc[0] = '\0';
      }

      prev_adapter = adapter;
   }

   if_freenameindex (ids);

   return ret_adapter;
}

/** Free memory allocated memory used by adapter collection.
 * @param[in] adapter = First element in linked list of adapters
 * EC_NOFRAME.
 */
void oshw_free_adapters(ec_adaptert * adapter)
{
   ec_adaptert * next_adapter;
   /* Iterate the linked list and free all elemnts holding
    * adapter information
    */
   if(adapter)
   {
      next_adapter = adapter->next;
      free (adapter);
      while (next_adapter)
      {
         adapter = next_adapter;
         next_adapter = adapter->next;
         free (adapter);
      }
   }
}