monitor_util.c

mobile ip 在linux下的一种实现

/* $Id: monitor_util.c,v 1.13 2001/09/29 16:06:39 jm Exp $
 * Monitor utilities module
 *
 * Dynamic hierarchial IP tunnel
 * Copyright (C) 1998-2000, Dynamics group
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation. See README and COPYING for
 * more details.
 */

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <assert.h>
#include <string.h>
#include <stddef.h>
#include "monitor.h"
#include "debug.h"
#include "mn.h" /* MAX_INTERFACES */

#define DEBUG_FLAG 'm' /* same as in monitor.c */

extern struct monitor_global_data mon_conf;
extern struct monitor_interface mon_devs[MAX_INTERFACES];


int next(int p)
{
	assert(p >= 0);
	if (p == 9)
		return 0;
	return p + 1;

}


int prev(int p)
{
	assert(p >= 0);
	if (p == 0)
		return 9;
	return p - 1;
}


/* return:
 *   <0  worst happens to be the current FA :(
 *   >0  the released slot
 */
int drop_worst(struct timeval *tstamp, struct monitor_interface *dev)
{
	int worst_avg = 1000; /* theoretical max quality is below */
	int worst_index = -2, i;

	/* (POLICY) */
	/* Find old entries */
	for (i = 0; i < MAX_MONITOR; i++) {
		/* old ghost. If MAX_TIME has passed
		 * for this entry and it still doesn't
		 * have decent values, just drop it */
		if (dev->mon[i].added.tv_sec + 
		    mon_conf.worst_max_time < tstamp->tv_sec &&
		    dev->mon[i].avg == 0)
			return i;
	}

	/* No old entries found. Find the worst entry */
	for (i = 0; i < MAX_MONITOR; i++) {
		if ((dev->mon[i].added.tv_sec + 
		     mon_conf.worst_min_time) > tstamp->tv_sec)
			return -1; /* new entry. Don't update faster than
				    * in MIN_TIME interval */
		if (dev->mon[i].avg < worst_avg) {
			worst_avg = dev->mon[i].avg;
			worst_index = i;
		}
	}

	if (worst_index >= 0 && worst_index != mon_conf.current_fa)
		return worst_index;

	/* worst one is current FA :( */
	return -1;
}


int get_free_slot(struct timeval *tstamp, struct monitor_interface *dev)
{
	int i, ph;

	for (i = 0; i < MAX_MONITOR; i++) {
		if (dev->mon[i].active != 1)
			return i;
	}

	/* no non-active entries found */
	ph = drop_worst(tstamp, dev);
	if (ph < 0) {
		DEBUG(DEBUG_FLAG, "get_free_slot: Working set is full, "
		      "worst entry just changed. Not dropped.\n");
		return -1;
	}

	DEBUG(DEBUG_FLAG, "get_free_slot: Working set is full, "
	      "worst entry dropped (%s).\n",
	      inet_ntoa(dev->mon[ph].adv->addr));
	return ph;
}


struct monitor_interface *monitor_get_dev(char *ifname)
{
	int i;

	DEBUG(DEBUG_FLAG, "monitor_get_dev: %s (len %d), interfaces %d\n",
	      ifname, strlen(ifname), mon_conf.interfaces);
	if (ifname == NULL) {
		DEBUG(DEBUG_FLAG, "monitor_get_dev: ifname == NULL!\n");
		return NULL;
	}

	for(i = 0; i< MAX_INTERFACES; i++) {
		if (mon_devs[i].in_use && 
		    !strncmp(ifname, mon_devs[i].ifname, IFNAMSIZ)) {
			return &mon_devs[i];
		}
	}

	DEBUG(DEBUG_FLAG, "monitor_get_dev: interface %s not found\n",
	      ifname);
	return NULL;
}


void print_entries(void)
{
	int i, j;

	for (j = 0; j < MAX_INTERFACES; j++) {
		if (!mon_devs[j].in_use)
			continue;
		for (i = 0; i < MAX_MONITOR; i++) {
			if (mon_devs[j].mon[i].active == 1) {
				DEBUG(DEBUG_FLAG, "%-15s: prio %d\n",
				      inet_ntoa(mon_devs[j].mon[i].adv->addr),
				      mon_devs[j].mon[i].adv->priority);
			}
		}
	}
}