event_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 "event_queue.h"
/****************************************************

   event_queue
----------------------------------------------------
This is a queue used to store events which have
to be dealt with. They are queued instead of
being acted on directly because a lot of the
events are recieved on interupts and you want
to limit the amount of work being done on
interupts!
****************************************************/

extern u_int32_t g_broadcast_ip;
struct event_queue_entry *event_queue;
struct event_queue_entry *end_event_queue;
spinlock_t event_lock = SPIN_LOCK_UNLOCKED;


void lock_event()
{
  spin_lock_bh(&event_lock);
}

void unlock_event()
{
  spin_unlock_bh(&event_lock);
}


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

   insert_event_queue_entry
----------------------------------------------------
Inserts an event into the event queue. dev is the
device the event was recieved on. data points
to the event itself.
****************************************************/

int insert_event_queue_entry(int type,struct sk_buff *packet)
{
  struct event_queue_entry *new_entry;
  struct interface_list_entry *tmp_interface;
  struct iphdr *ip;

  int start_point=sizeof(struct udphdr)+sizeof(struct iphdr);



  if ((new_entry = (struct event_queue_entry*)kmalloc(sizeof(struct event_queue_entry),GFP_ATOMIC)) == NULL)
    {
      printk(KERN_WARNING "AODV: Not enough memory to create Event Queue Entry\n");
      return -ENOMEM;
    }


  new_entry->time = getcurrtime();
  new_entry->type = type;
  new_entry->prev = NULL;

  if (type<100)
    {
      ip  = packet->nh.iph;
      new_entry->src_ip = ip->saddr;
      new_entry->dst_ip = ip->daddr;
      new_entry->ttl = ip->ttl;
      new_entry->dev = packet->dev;
      new_entry->size = packet->len-start_point;
      
      //create space for the data and copy it there
      if ((new_entry->data = kmalloc(new_entry->size,GFP_ATOMIC)) ==  NULL)
	{
	  kfree(new_entry);
	  printk(KERN_WARNING "AODV: Not enough memory to create Event Queue Data Entry\n");
	  return -ENOMEM;
	}

      memcpy(new_entry->data,packet->data+start_point,new_entry->size);
    }
  


  switch (type)
    {
      //RREP
    case EVENT_RREP:
      memcpy(&(new_entry->src_hw_addr),&(packet->mac.ethernet->h_source),sizeof(unsigned char)*ETH_ALEN);
      break;
      
    default:
      break;
    }

 /*lock table*/
    lock_event();
  
  //Set all the variables
  new_entry->next=event_queue;

  if (event_queue==NULL)
      end_event_queue=new_entry;
  else
      event_queue->prev=new_entry;

  
  event_queue=new_entry;
  
  
  /*unlock table*/
  unlock_event();

  //wake up the AODV thread
  kick_aodv();
  
  return 0;

}

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

   get_last_event_queue_entry
----------------------------------------------------
Gets the last entry from the event queue
****************************************************/

struct event_queue_entry *get_next_event_queue_entry( void )
{
  struct event_queue_entry *temp_entry=NULL;

  /*lock table*/
  lock_event();
  
  if (end_event_queue!=NULL)
    {
      temp_entry=end_event_queue;
      if (temp_entry->prev==NULL)
	{
	  end_event_queue=NULL;
	  event_queue=NULL;
	}
      else
	{
	  end_event_queue=temp_entry->prev;
	  end_event_queue->next=NULL;
	}
    }

  /*unlock table*/
  unlock_event();

  return temp_entry;
  
}

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

   init_event_queue
----------------------------------------------------
Initalizes the event queue
****************************************************/
int init_event_queue( void )
{
    event_queue = NULL;
    end_event_queue = NULL;
    return 0;
}


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

   cleanup_event_queue
----------------------------------------------------
Deletes eveything in the event queue!
****************************************************/
int cleanup_event_queue(void )
{
  struct event_queue_entry *temp_entry=NULL;

  while ((temp_entry=get_next_event_queue_entry())!=NULL)
    {
      kfree(temp_entry->data);
      kfree(temp_entry);
    }

 return 0;
}