/* * IPVS:        Round-Robin Scheduling module * * Version:     $Id: ip_vs_rr.c,v 1.9 2002/09/15 08:14:08 wensong Exp $ * * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org> *              Peter Kese <peter.kese@ijs.si> * *              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. * * Fixes/Changes: *     Wensong Zhang            :     changed the ip_vs_rr_schedule to return dest *     Julian Anastasov         :     fixed the NULL pointer access bug in debugging *     Wensong Zhang            :     changed some comestics things for debugging *     Wensong Zhang            :     changed for the d-linked destination list *     Wensong Zhang            :     added the ip_vs_rr_update_svc *     Wensong Zhang            :     added any dest with weight=0 is quiesced * */#include <linux/module.h>#include <linux/kernel.h>#include <net/ip_vs.h>static int ip_vs_rr_init_svc(struct ip_vs_service *svc){	svc->sched_data = &svc->destinations;	return 0;}static int ip_vs_rr_done_svc(struct ip_vs_service *svc){	return 0;}static int ip_vs_rr_update_svc(struct ip_vs_service *svc){	svc->sched_data = &svc->destinations;	return 0;}/* * Round-Robin Scheduling */static struct ip_vs_dest *ip_vs_rr_schedule(struct ip_vs_service *svc, const struct sk_buff *skb){	struct list_head *p, *q;	struct ip_vs_dest *dest;	IP_VS_DBG(6, "ip_vs_rr_schedule(): Scheduling...\n");	write_lock(&svc->sched_lock);	p = (struct list_head *)svc->sched_data;	p = p->next;	q = p;	do {		/* skip list head */		if (q == &svc->destinations) {			q = q->next;			continue;		}				dest = list_entry(q, struct ip_vs_dest, n_list);		if (!(dest->flags & IP_VS_DEST_F_OVERLOAD) &&		    atomic_read(&dest->weight) > 0)			/* HIT */			goto out;		q = q->next;	} while (q != p);	write_unlock(&svc->sched_lock);	return NULL;  out:	svc->sched_data = q;	write_unlock(&svc->sched_lock);	IP_VS_DBG(6, "RR: server %u.%u.%u.%u:%u "		  "activeconns %d refcnt %d weight %d\n",		  NIPQUAD(dest->addr), ntohs(dest->port),		  atomic_read(&dest->activeconns),		  atomic_read(&dest->refcnt), atomic_read(&dest->weight));	return dest;}static struct ip_vs_scheduler ip_vs_rr_scheduler = {	.name =			"rr",			/* name */	.refcnt =		ATOMIC_INIT(0),	.module =		THIS_MODULE,	.init_service =		ip_vs_rr_init_svc,	.done_service =		ip_vs_rr_done_svc,	.update_service =	ip_vs_rr_update_svc,	.schedule =		ip_vs_rr_schedule,};static int __init ip_vs_rr_init(void){	INIT_LIST_HEAD(&ip_vs_rr_scheduler.n_list);	return register_ip_vs_scheduler(&ip_vs_rr_scheduler);}static void __exit ip_vs_rr_cleanup(void){	unregister_ip_vs_scheduler(&ip_vs_rr_scheduler);}module_init(ip_vs_rr_init);module_exit(ip_vs_rr_cleanup);MODULE_LICENSE("GPL");