flood_id_queue.c

linux 下的aodv实现源代码

/*
               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: [e-mail]

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

*/

#include "flood_id_queue.h"
/****************************************************

   flood_id_queue
----------------------------------------------------
This is used to keep track of messages which
are flooded to prevent rebroadcast of messages
****************************************************/

extern struct flood_id_queue_entry *rreq_id_queue;
rwlock_t rreq_lock = RW_LOCK_UNLOCKED;


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

   init_flood_id_queue
----------------------------------------------------
Gets the ball rolling!
****************************************************/

int init_flood_id_queue( void )
{
    rreq_id_queue=NULL;

    return 0;
}

void flood_read_lock()
{
   write_lock_bh(&rreq_lock);
}

void flood_read_unlock()
{
  write_unlock_bh(&rreq_lock);
}

void flood_write_lock()
{
  write_lock_bh(&rreq_lock);
}

void flood_write_unlock()
{
  write_unlock_bh(&rreq_lock);
}


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

   find_flood_id_queue_entry
----------------------------------------------------
will search the queue for an entry with the
matching ID and src_ip
****************************************************/
struct flood_id_queue_entry *find_flood_id_queue_entry(u_int32_t src_ip, u_int32_t flood_id )
{
  struct flood_id_queue_entry  *tmp_entry;  /* Working entry in the RREQ list */

  
  u_int64_t curr=getcurrtime();
  

  /*lock table*/
  flood_read_lock();
  
  tmp_entry = rreq_id_queue; /* Start at the header */

  //go through the whole queue
  while (tmp_entry!=NULL)
    {
      
	if(tmp_entry->lifetime<curr)
	{
	  /*unlock table*/
	  flood_read_unlock();

	  return NULL;
	}
      
	//if there is a match and it is still valid
	if (src_ip == tmp_entry->src_ip && flood_id == tmp_entry->flood_id)
	  {
	    /*unlock table*/
	    flood_read_unlock();

	    return tmp_entry;
	  }
	


	//continue on to the next entry
	tmp_entry=tmp_entry->next;
	
	
	
    }
  /*unlock table*/
  flood_read_unlock();

  return NULL;
}


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

   read_flood_id_proc
----------------------------------------------------
prints out the flood id queue when the proc
file is read
****************************************************/
int read_rreq_id_proc(char *buffer, char **buffer_location, off_t offset, int buffer_length,int *eof,void *data)
{
  int len;
  static char *my_buffer;
  char temp_buffer[200];
  struct flood_id_queue_entry *tmp_entry;
  char tmp[16];
  u_int64_t tmp_time;


    /*lock table*/
    flood_read_lock();

  tmp_entry=rreq_id_queue;
  
  my_buffer=buffer;
  sprintf(my_buffer,"\nFlood Id Queue\n---------------------------------\n");
  
  while (tmp_entry!=NULL)
    {
      tmp_time=tmp_entry->lifetime-getcurrtime();
      strcpy(tmp,inet_ntoa(tmp_entry->dst_ip));
      sprintf(temp_buffer,"Src IP: %-16s  Dst IP: %-16s Flood ID: %-10u sec/msec: %lu/%lu \n", inet_ntoa(tmp_entry->src_ip),tmp,tmp_entry->flood_id,100,100);//,(unsigned long)(tmp_time) / 1000, (unsigned long)(tmp_time) % 1000);
      strcat(my_buffer,temp_buffer);
      tmp_entry=tmp_entry->next;
    }

    /*unlock table*/
    flood_read_unlock();

    sprintf(temp_buffer,"\n---------------------------------\n");
    strcat(my_buffer,temp_buffer);

    *buffer_location=my_buffer;
    len = strlen(my_buffer);
    if (len <= offset+buffer_length) *eof = 1;
    *buffer_location = my_buffer + offset;
    len -= offset;
    if (len>buffer_length) len = buffer_length;
    if (len<0) len = 0;
    return len;

}



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

   print_flood_id_queue
----------------------------------------------------
prints out the flood id queue onto the console
screen
****************************************************/
void print_flood_id_queue()
{
    struct flood_id_queue_entry *tmp_entry;
    char tmp[16];
    tmp_entry= rreq_id_queue;

    printk(KERN_INFO "Flood ID list:\n");
    while (tmp_entry!=NULL)
    {
        strcpy(tmp,inet_ntoa(tmp_entry->dst_ip));
        printk(KERN_INFO "Src IP: %-16s  Dst IP: %-16s Flood ID: %-10u  \n", inet_ntoa(tmp_entry->src_ip),tmp,tmp_entry->flood_id);
        tmp_entry=tmp_entry->next;
    }
}

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

   clean_up_flood_id_queue
----------------------------------------------------
Deletes everything in the flood id queue
****************************************************/
void cleanup_flood_id_queue()
{
    struct flood_id_queue_entry *tmp_entry,*dead_entry;
    int count=0;

    tmp_entry=rreq_id_queue;

    print_flood_id_queue();

    while (tmp_entry!=NULL)
    {
        dead_entry=tmp_entry;
        tmp_entry=tmp_entry->next;
        kfree(dead_entry);
        count++;
    }
    rreq_id_queue=NULL;

    printk(KERN_INFO "Removed %d Flood ID entries! \n",count);
    printk(KERN_INFO "---------------------------------------------\n");

}

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

   insert_flood_id_queue_entry
----------------------------------------------------
Inserts an entry into the flood ID queue
****************************************************/
int insert_flood_id_queue_entry(u_int32_t ip, u_int32_t dst_ip,u_int32_t id, u_int64_t lt)
{
    struct flood_id_queue_entry  *new_entry; /* Pointer to the working entry */


    /* Allocate memory for the new entry */
    if ((new_entry = (struct flood_id_queue_entry*)kmalloc(sizeof(struct flood_id_queue_entry),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;
    }
    
    /* Fill in the information in the new entry */
    new_entry->src_ip = ip;
    new_entry->dst_ip = dst_ip;
    new_entry->flood_id = id;
    new_entry->lifetime = lt;


    /*lock table*/
    flood_write_lock();


    new_entry->next = rreq_id_queue;
    /* Put the new entry in the list */
    rreq_id_queue=new_entry;

    /*unlock table*/
    flood_write_unlock();

    return 0;
}

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

   check_flood_id_queue_entry_lifetime
----------------------------------------------------
Checks the lifetime of a flood ID queue entry.
Returns 0 if it is valid and 1 if it is not!
****************************************************/
int check_flood_id_queue_entry_lifetime(struct flood_id_queue_entry *tmp_entry)
{
    u_int64_t  curr_time = getcurrtime(); /* Current time */

    /* Check if the entry is valid */
    if ((tmp_entry!=NULL )&&(curr_time > tmp_entry->lifetime))
    {
        return 1;
    }

    if (tmp_entry==NULL)
      {
        printk(KERN_WARNING "AODV: check_flood_id_queue_lifetime passed a NULL\n");
      }

    return 0;
}

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

   delete_old_flood_id_queue_entries
----------------------------------------------------
Goes through the flood ID queue and deletes
all of the old entries
****************************************************/
int delete_old_flood_id_queue_entries( ) 
{
    struct flood_id_queue_entry *tmp_entry,*prev_entry,*dead_entry;

    u_int64_t  curr_time = getcurrtime(); /* Current time */
    int c=0;


    /*lock table*/
    flood_write_lock( );


    tmp_entry= rreq_id_queue;
    prev_entry=NULL;

    //go through the entire queue
    while(tmp_entry!=NULL)
    {
      c++;
        //if the entry has expired
      if (curr_time > tmp_entry->lifetime)
        {

	  
	  //if it is the first entry
	  if(prev_entry==NULL)
	    rreq_id_queue=tmp_entry->next;
	  else
	    prev_entry->next=tmp_entry->next;
	  
	  //kill it!
	  dead_entry=tmp_entry;
	  tmp_entry=tmp_entry->next;
	  kfree(dead_entry);

        }
      else
        {

	  
	  //next entry
	  prev_entry=tmp_entry;
	  tmp_entry=tmp_entry->next;
	  

        }
    }

    /*unlock table*/
    flood_write_unlock( );

    return c;
}

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

   delete_flood_id_queue_entry
----------------------------------------------------
Deletes a flood id queue entry
****************************************************/
int delete_flood_id_queue_entry(struct flood_id_queue_entry *dead_entry )
{
    struct flood_id_queue_entry *tmp_entry, *prev_entry;

    tmp_entry= rreq_id_queue;
    prev_entry=NULL;

    //since we don't know the previous entry we have to go
    //through entire list to find it!
    while (tmp_entry!=NULL)
    {
        //if we find the entry we wish to delete
        if(tmp_entry==dead_entry)
        {
            if (prev_entry==NULL)
               rreq_id_queue=tmp_entry->next;
            else
                prev_entry->next=tmp_entry->next;
            kfree(tmp_entry);
            return 0;
        }
        tmp_entry=tmp_entry->next;
    }
    return 1;
}