rebroadcast_list.c

説明を見る。

/*
               Kernel AODV  v2.1
National Institute of Standards and Technology
               Luke Klein-Berndt
-----------------------------------------------------
  Version 2.1 new features:
     * Much more stable!
     * Added locks around important areas
     * Multihop Internet gatewaying now works
     * Multicast hack added
     * Many bug fixes!
-----------------------------------------------------

Originally based upon MadHoc code. I am not
sure how much of it is left anymore, but MadHoc
proved to be a great starting point.

MadHoc was written by - Fredrik Lilieblad,
Oskar Mattsson, Petra Nylund, Dan Ouchterlony
and Anders Roxenhag Mail: mad-hoc@flyinglinux.net

This software is Open Source under the GNU General Public Licence.

*/


/****************************************************

   rebroadcast_list
----------------------------------------------------
Rebroadcast List keeps track of the packets which
have been rebroadcasted. It makes sure that a packet
does not get reboradcasted twice... duplicate packets
are bad! It does this by keep a list of the past N
sequence numbers. There is a seperate list for each
neighboring node. If a packet's seq num is below
the lower bounds of the list then it is assumed that
the packet is too old. If it falls in range of the
list, it is checked to see if it has been recieved
prior, if not it is rebroadcast.
****************************************************/


#include "rebroadcast_list.h"

#ifdef AODV_MULTICAST

struct ticket *ticket_roll[256];


void init_check()
{
  int i;
  for (i=0;i<ROLL_SIZE;i++)
    {
      ticket_roll[i]=NULL;
    }
}



int check_check(u_int32_t ip, u_int16_t id)
{
  u_int8_t target;
  int32_t amount;
  int point;
  int i;

  unsigned char *ucp = (unsigned char *)&ip;
  target=(ucp[3] & 0xff);

  if (ticket_roll[target]==NULL)
    {
      if ((ticket_roll[target] = (struct ticket*)kmalloc(sizeof(struct ticket),GFP_ATOMIC)) == NULL)
        {
          printk(KERN_WARNING "AODV: Not enough memory to create Flood ID queue\n");

          /* Failed to allocate memory for new Flood ID queue */
          return -ENOMEM;
        }




      memset(ticket_roll[target]->check,0,sizeof(u_int8_t)*LIST_SIZE);
      ticket_roll[target]->last_checked=0;
      ticket_roll[target]->current_check=0;
      ticket_roll[target]->check_amount=0;
     }



  amount=id-ticket_roll[target]->check_amount;

  if (amount < -LIST_SIZE)
    {
      if (getcurrtime()-ticket_roll[target]->last_checked>10000)
        {
          memset(ticket_roll[target]->check,0,sizeof(u_int8_t)*LIST_SIZE);
          ticket_roll[target]->last_checked=getcurrtime();
          ticket_roll[target]->current_check=0;
          ticket_roll[target]->check_amount=id;
          printk("IP: %s ID: %u RESTARTED!!!!!!!!!!!!\n",inet_ntoa(ip),id);
          return 1;
        }
      
      printk(" %d ID: %u Amount %d Current %d been forever!\n",target,id,amount,ticket_roll[target]->check_amount);
      return 0;
    }

  //new_position=(LIST_SIZE+amount)%LIST_SIZE;
  


  if (amount>0)
    {
      amount=amount % LIST_SIZE;
      for (i=0;i<=amount;i++)
        {
          point=(i+ticket_roll[target]->current_check) % LIST_SIZE;
          ticket_roll[target]->check[point]=0;
        }
      ticket_roll[target]->last_checked=getcurrtime();
      ticket_roll[target]->current_check=point;//(amount+ticket_roll[target]->current_check+LIST_SIZE) % LIST_SIZE;
      ticket_roll[target]->check_amount=id;
      //        printk("IP: %s ID: %u New!\n",inet_ntoa(ip),id);
        ticket_roll[target]->check[point]=1;
        return 1;
    }
    point=(amount+ticket_roll[target]->current_check+LIST_SIZE) % LIST_SIZE;
    if (ticket_roll[target]->check[point])
      {
        //printk("IP: %s ID: %u already recieved!\n",inet_ntoa(ip),id);

        return 0;
      }
    else
      {
        //printk("IP: %s ID: %u New!\n",inet_ntoa(ip),id);
        ticket_roll[target]->check[point]=1;
        return 1;
      }
}
#endif

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