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