kaodv-expl.c

在ns2.28中实现的AODV的升级版本AODV－

/*****************************************************************************
 *
 * Copyright (C) 2001 Uppsala University and Ericsson AB.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Erik Nordström, <[e-mail]>
 *
 *****************************************************************************/
/* Expire list for aodv route information */

#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <linux/proc_fs.h>

#include "kaodv-expl.h"
#include "kaodv-netlink.h"
#include "kaodv-queue.h"

#define EXPL_MAX_LEN 1024

static unsigned int expl_len;
static rwlock_t expl_lock = RW_LOCK_UNLOCKED;
static LIST_HEAD(expl_head);

#define list_is_first(e) (&e->l == expl_head.next)

/* Timers and timeouts could potentially be handled in the kernel. However,
 * currently they are not, because it complicates things quite a bit. The code
 * for adding timers is still here though... - Erik */

#ifdef EXPL_TIMER
static struct timer_list expl_timer;

static void kaodv_expl_timeout(unsigned long data);

static inline void __kaodv_expl_set_next_timeout(void)
{
    struct expl_entry *ne;
    
    if (list_empty(&expl_head)) 
	return;

    /* Get first entry */
    ne = (struct expl_entry *)expl_head.next;

    if (timer_pending(&expl_timer)) {
	mod_timer(&expl_timer, ne->expires);
    } else {
	expl_timer.function = kaodv_expl_timeout;
	expl_timer.expires = ne->expires;
	expl_timer.data = 0;
	add_timer(&expl_timer);
    }
}

static void kaodv_expl_timeout(unsigned long data)
{
    struct list_head *pos, *tmp;
    int time = jiffies;
    
    write_lock_bh(&expl_lock);
    
    list_for_each_safe(pos, tmp, &expl_head) {
	struct expl_entry *e = (struct expl_entry *)pos;
	
	if (e->expires > time)
	    break;
	
	list_del(&e->l);
	expl_len--;

	/* Flush any queued packets for this dest */
	kaodv_queue_set_verdict(KAODV_QUEUE_DROP, e->daddr);

	/* printk("expl_timeout: sending timeout event!\n"); */
	kaodv_netlink_send_rt_msg(KAODVM_TIMEOUT, e->daddr); 
    }
    __kaodv_expl_set_next_timeout();
    write_unlock_bh(&expl_lock);
}
#endif  /* EXPL_TIMER */

char inline *print_ip(__u32 addr)
{
   static char buf[16];
   
   sprintf(buf, "%d.%d.%d.%d",
	   0x0ff & addr,
	   0x0ff & (addr >> 8),
	   0x0ff & (addr >> 16),
	   0x0ff & (addr >> 24));

   return buf;
}

static inline void __kaodv_expl_flush(void)
{
    struct list_head *pos, *tmp;
    
    list_for_each_safe(pos, tmp, &expl_head) {
	struct expl_entry *e = (struct expl_entry *)pos;
	list_del(&e->l);
	expl_len--;
	kfree(e);
    }
}

static inline int __kaodv_expl_add(struct expl_entry *e)
{
    
    if (expl_len >= EXPL_MAX_LEN) {
	printk(KERN_WARNING "kaodv_expl: Max list len reached\n");
	return -ENOSPC;
    }
    
    if (list_empty(&expl_head)) {
	list_add(&e->l, &expl_head);
    } else {
	struct list_head *pos;
	
	list_for_each(pos, &expl_head) {
	    struct expl_entry *curr = (struct expl_entry *)pos;
	    
	    if (curr->expires > e->expires) 
		break;
	}
	list_add(&e->l, pos->prev);
    }
    return 1;
}

static inline struct expl_entry *__kaodv_expl_find(__u32 daddr)
{
    struct list_head *pos;
    
    list_for_each(pos, &expl_head) {
	struct expl_entry *e = (struct expl_entry *)pos;
	
	if (e->daddr == daddr)
	    return e;
    }
    return NULL;
}

static inline int __kaodv_expl_del(struct expl_entry *e)
{
    if (e == NULL)
	return 0;
    
     if (list_is_first(e)) {
	 
	list_del(&e->l);
#ifdef EXPL_TIMER
	if (!list_empty(&expl_head)) {
	    /* Get the first entry */
	    struct expl_entry *f = (struct expl_entry *)expl_head.next;
	    
	    /* Update the timer */
	    mod_timer(&expl_timer, f->expires);
	}
#endif
    } else
	list_del(&e->l);
    
    return 1;
}

int kaodv_expl_del(__u32 daddr)
{
    int res;
    struct expl_entry *e;
  
    write_lock_bh(&expl_lock); 
    
    e = __kaodv_expl_find(daddr);

    if (e == NULL) {
	res = 0;
	goto unlock;
    }
    
    res = __kaodv_expl_del(e);
    
    if (res)
	kfree(e);
 unlock:
    write_unlock_bh(&expl_lock);
    
    return res;
}

int kaodv_expl_get(__u32 daddr, struct expl_entry *e_in)
{
    struct expl_entry *e;
    int res = 0;
    
/*     printk("Checking activeness\n"); */
    read_lock_bh(&expl_lock);
    e = __kaodv_expl_find(daddr);
    
    if (e) {
	res = 1;
	if (e_in)
	    memcpy(e_in, e, sizeof(struct expl_entry));
    }
	
    read_unlock_bh(&expl_lock);
    return res;
}


int kaodv_expl_add(__u32 daddr, __u32 nhop, unsigned long time, 
		   unsigned short flags)
{
    struct expl_entry *e;
    int status = 0;
    
    if (kaodv_expl_get(daddr, NULL))
	return 0;
    
    e = kmalloc(sizeof(*e), GFP_ATOMIC);
    
    if (e == NULL) {
	printk(KERN_ERR "expl: OOM in expl_add\n");
	return -ENOMEM;
    }
    
    e->daddr = daddr;
    e->nhop = nhop;
    e->flags = flags;
    e->expires = jiffies + (time * HZ) / 1000;

    write_lock_bh(&expl_lock);
    
    status = __kaodv_expl_add(e);
    
    if (status)
	expl_len++;

#ifdef EXPL_TIMER
    /* If the added element was added first in the list we update the timer */
    if (status && list_is_first(e)) {
	
	if (timer_pending(&expl_timer))
	    mod_timer(&expl_timer, e->expires);
	else {
	    expl_timer.function = expl_timeout;
	    expl_timer.expires = e->expires;
	    expl_timer.data = 0;
	    add_timer(&expl_timer);
	}
    }
#endif
    write_unlock_bh(&expl_lock);
    
    if (status < 0)
	kfree(e);
    
    return status;
}

static int kaodv_expl_print(char *buf)
{
    struct list_head *pos;
    int len = 0;
    
    read_lock_bh(&expl_lock);
    
    len += sprintf(buf, "# %-15s %-15s %-5s Expires\n", "Addr", "Nhop", "Flags");

    list_for_each(pos, &expl_head) {
	char addr[16], nhop[16], flags[4];
	int num_flags = 0;
	struct expl_entry *e = (struct expl_entry *)pos;
		
	sprintf(addr, "%d.%d.%d.%d",
		0x0ff & e->daddr,
		0x0ff & (e->daddr >> 8),
		0x0ff & (e->daddr >> 16),
		0x0ff & (e->daddr >> 24));
	
	sprintf(nhop, "%d.%d.%d.%d",
		0x0ff & e->nhop,
		0x0ff & (e->nhop >> 8),
		0x0ff & (e->nhop >> 16),
		0x0ff & (e->nhop >> 24));
	
	if (e->flags & KAODV_RT_GW_ENCAP)
	    flags[num_flags++] = 'E';
	
	if (e->flags & KAODV_RT_REPAIR)
	    flags[num_flags++] = 'R';
	    
	flags[num_flags] = '\0';
	
	len += sprintf(buf+len, "  %-15s %-15s %-5s %lu\n", addr, nhop, flags, 
		       (e->expires - jiffies) * 1000 / HZ);
    }
    
    read_unlock_bh(&expl_lock);
    return len;
}
static int kaodv_expl_proc_info(char *buffer, char **start, off_t offset, int length)
{
    int len;

    len = kaodv_expl_print(buffer);
    
    *start = buffer + offset;
    len -= offset;
    if (len > length)
	len = length;
    else if (len < 0)
	len = 0;
    return len;    
}

void kaodv_expl_update(__u32 daddr, __u32 nhop, unsigned long time, 
		       unsigned short flags)
{
    struct expl_entry *e;

    write_lock_bh(&expl_lock); 
    
    e = __kaodv_expl_find(daddr);

    if (e == NULL) {
	/* printk("expl_update: No entry to update!\n"); */
	goto unlock;
    }
    e->nhop = nhop;
    e->flags = flags;
    /* Update expire time */
    e->expires = jiffies + (time * HZ) / 1000;

    /* Remove from list */    
    list_del(&e->l);
    __kaodv_expl_add(e);
#ifdef EXPL_TIMER
    __kaodv_expl_set_next_timeout();
#endif
    
 unlock:
    write_unlock_bh(&expl_lock); 
}

void kaodv_expl_flush(void)
{
#ifdef EXPL_TIMER
    if (timer_pending(&expl_timer))
	del_timer(&expl_timer);
#endif

    write_lock_bh(&expl_lock);

    __kaodv_expl_flush();

    write_unlock_bh(&expl_lock);
}

void kaodv_expl_init(void)
{
    proc_net_create("kaodv_expl", 0, kaodv_expl_proc_info);

#ifdef EXPL_TIMER
    init_timer(&expl_timer);
#endif
}
void kaodv_expl_fini(void)
{
    kaodv_expl_flush();
    proc_net_remove("kaodv_expl");
}