packet_queue.cc

在ns2.28中实现的AODV的升级版本AODV－

/*****************************************************************************
 *
 * Copyright (C) 2001 Uppsala University & 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
 *
 * Authors: Erik Nordstr鰉, <[e-mail]>
 *
 *****************************************************************************/

#include "aodv-uu.h"

#define GARBAGE_COLLECT

void NS_CLASS packet_queue_init(void)
{
    INIT_LIST_HEAD(&PQ.head);
    PQ.len = 0;

#ifdef GARBAGE_COLLECT
    /* Set up garbage collector */
    timer_init(&PQ.garbage_collect_timer, &NS_CLASS packet_queue_timeout, &PQ);

    timer_set_timeout(&PQ.garbage_collect_timer, GARBAGE_COLLECT_TIME);
#endif
}


void NS_CLASS packet_queue_destroy(void)
{
    int count = 0;
    list_t *pos, *tmp;
    
    list_foreach_safe(pos, tmp, &PQ.head) {
	struct q_pkt *qp = (struct q_pkt *)pos;
	list_detach(pos);

	drop(qp->p, DROP_END_OF_SIMULATION);

	free(qp);
	count++;
	PQ.len--;
    }

    DEBUG(LOG_INFO, 0, "Destroyed %d buffered packets!", count);
}

/* Garbage collect packets which have been queued for too long... */
int NS_CLASS packet_queue_garbage_collect(void)
{
    int count = 0;
    list_t *pos, *tmp;
    struct timeval now;
    
    gettimeofday(&now, NULL);
    
    list_foreach_safe(pos, tmp, &PQ.head) {
	struct q_pkt *qp = (struct q_pkt *)pos;
	if (timeval_diff(&now, &qp->q_time) > MAX_QUEUE_TIME) {
	   
	    list_detach(pos);

	    drop(qp->p, DROP_RTR_QTIMEOUT); 
	    
	    free(qp);
	    count++;
	    PQ.len--;
	}
    }
    
    if (count) {
        DEBUG(LOG_DEBUG, 0, "Removed %d packet(s)!", count);
    }
    
    return count;
}
/* Buffer a packet in a FIFO queue. Implemented as a linked list,
   where we add elements at the end and remove at the beginning.... */

void NS_CLASS packet_queue_add(Packet * p, struct in_addr dest_addr)
{
    struct q_pkt *qp;
    struct hdr_ip *ih;
    struct hdr_cmn *ch = HDR_CMN(p);
    
    ih = HDR_IP(p);
    
    assert(ih->daddr() == dest_addr.s_addr);

    if (PQ.len >= MAX_QUEUE_LENGTH) {
	DEBUG(LOG_DEBUG, 0, "MAX Queue length! Removing first packet.");
	if (!list_empty(&PQ.head)) {
	    qp = (struct q_pkt *)PQ.head.next;
	    
	    list_detach(PQ.head.next);

	    drop(qp->p, DROP_RTR_QFULL);
	    free(qp);
	    PQ.len--;
	}
    }

    qp = (struct q_pkt *) malloc(sizeof(struct q_pkt));
    
    if (qp == NULL) {
	fprintf(stderr, "Malloc failed!\n");
	exit(-1);
    }

    qp->p = p;

    qp->dest_addr = dest_addr;
    
    gettimeofday(&qp->q_time, NULL);
    
    list_add_tail(&PQ.head, &qp->l);

    PQ.len++;

    DEBUG(LOG_INFO, 0, "buffered pkt to %s uid=%d qlen=%u",
	  ip_to_str(dest_addr), ch->uid(), PQ.len);
}

int NS_CLASS packet_queue_set_verdict(struct in_addr dest_addr, int verdict)
{
    int count = 0;
    rt_table_t *rt, *next_hop_rt, *inet_rt = NULL;
    list_t *pos, *tmp;

    double delay = 0;
#define ARP_DELAY 0.005
    
    if (verdict == PQ_ENC_SEND) {
	inet_rt = rt_table_find(dest_addr);
	
	if (!inet_rt)
	    return -1;
	rt = rt_table_find(inet_rt->next_hop);
    } else {
	rt = rt_table_find(dest_addr);
    }
    
    list_foreach_safe(pos, tmp, &PQ.head) {
	 struct q_pkt *qp = (struct q_pkt *)pos;

	if (qp->dest_addr.s_addr == dest_addr.s_addr) {
	    
	    list_detach(pos);
	    
	    switch (verdict) {
	    case PQ_SEND:
		
		if (!rt)
		    return -1;

		/* Apparently, the link layer implementation can't handle
		 * a burst of packets. So to keep ARP happy, buffered
		 * packets are sent with ARP_DELAY seconds between
		 * sends. */
		sendPacket(qp->p, rt->next_hop, delay);
		delay += ARP_DELAY;
		break;
	    case PQ_DROP:

		drop(qp->p, DROP_RTR_NO_ROUTE);
		break;
#ifdef CONFIG_GATEWAY
	    case PQ_ENC_SEND:
		
		if (!rt)
		    return -1;

		DEBUG(LOG_DEBUG, 0, "Encap. PQ_ENC_SEND");

		qp->p = pkt_encapsulate(qp->p, inet_rt->next_hop);
		
		if (!qp->p) {
		    DEBUG(LOG_ERR, 0, "Encapsulation failed...");
		}	
		
		sendPacket(qp->p, rt->next_hop, delay);
		delay += ARP_DELAY;
		break;
#endif /* CONFIG_GATEWAY */
	    }
	    free(qp);
	    count++;
	    PQ.len--;
	}
    }

    /* Update rt timeouts */
    if (rt && rt->state == VALID && 
	(verdict == PQ_SEND || verdict == PQ_ENC_SEND)) {
	if (dest_addr.s_addr != DEV_IFINDEX(rt->ifindex).ipaddr.s_addr) {
	    if (verdict == PQ_ENC_SEND && inet_rt)
		rt_table_update_timeout(inet_rt, ACTIVE_ROUTE_TIMEOUT);
	    
	    rt_table_update_timeout(rt, ACTIVE_ROUTE_TIMEOUT);
	    
	    next_hop_rt = rt_table_find(rt->next_hop);
	    
	    if (next_hop_rt && next_hop_rt->state == VALID && 
		next_hop_rt->dest_addr.s_addr != rt->dest_addr.s_addr)
		rt_table_update_timeout(next_hop_rt, ACTIVE_ROUTE_TIMEOUT);
	}
	
	DEBUG(LOG_INFO, 0, "SENT %d packets to %s qlen=%u",
	      count, ip_to_str(dest_addr), PQ.len);
    } else if (verdict == PQ_DROP) {
	DEBUG(LOG_INFO, 0, "DROPPED %d packets for %s!",
	      count, ip_to_str(dest_addr));
    }

    return count;
}