[deliverable/linux.git] / net / netfilter / ipvs / ip_vs_ovf.c

/*
 * IPVS:        Overflow-Connection Scheduling module
 *
 * Authors:     Raducu Deaconu <rhadoo_io@yahoo.com>
 *
 *              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.
 *
 * Scheduler implements "overflow" loadbalancing according to number of active
 * connections , will keep all conections to the node with the highest weight
 * and overflow to the next node if the number of connections exceeds the node's
 * weight.
 * Note that this scheduler might not be suitable for UDP because it only uses
 * active connections
 *
 */

#define KMSG_COMPONENT "IPVS"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>

#include <net/ip_vs.h>

/* OVF Connection scheduling  */
static struct ip_vs_dest *
ip_vs_ovf_schedule(struct ip_vs_service *svc, const struct sk_buff *skb,
		   struct ip_vs_iphdr *iph)
{
	struct ip_vs_dest *dest, *h = NULL;
	int hw = 0, w;

	IP_VS_DBG(6, "ip_vs_ovf_schedule(): Scheduling...\n");
	/* select the node with highest weight, go to next in line if active
	* connections exceed weight
	*/
	list_for_each_entry_rcu(dest, &svc->destinations, n_list) {
		w = atomic_read(&dest->weight);
		if ((dest->flags & IP_VS_DEST_F_OVERLOAD) ||
		    atomic_read(&dest->activeconns) > w ||
		    w == 0)
			continue;
		if (!h || w > hw) {
			h = dest;
			hw = w;
		}
	}

	if (h) {
		IP_VS_DBG_BUF(6, "OVF: server %s:%u active %d w %d\n",
			      IP_VS_DBG_ADDR(h->af, &h->addr),
			      ntohs(h->port),
			      atomic_read(&h->activeconns),
			      atomic_read(&h->weight));
		return h;
	}

	ip_vs_scheduler_err(svc, "no destination available");
	return NULL;
}

static struct ip_vs_scheduler ip_vs_ovf_scheduler = {
	.name =			"ovf",
	.refcnt =		ATOMIC_INIT(0),
	.module =		THIS_MODULE,
	.n_list =		LIST_HEAD_INIT(ip_vs_ovf_scheduler.n_list),
	.schedule =		ip_vs_ovf_schedule,
};

static int __init ip_vs_ovf_init(void)
{
	return register_ip_vs_scheduler(&ip_vs_ovf_scheduler);
}

static void __exit ip_vs_ovf_cleanup(void)
{
	unregister_ip_vs_scheduler(&ip_vs_ovf_scheduler);
	synchronize_rcu();
}

module_init(ip_vs_ovf_init);
module_exit(ip_vs_ovf_cleanup);
MODULE_LICENSE("GPL");
Commit	Line	Data
eefa32d3 RD	1	/*
	2	* IPVS: Overflow-Connection Scheduling module
	3	*
	4	* Authors: Raducu Deaconu <rhadoo_io@yahoo.com>
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*
	11	* Scheduler implements "overflow" loadbalancing according to number of active
	12	* connections , will keep all conections to the node with the highest weight
	13	* and overflow to the next node if the number of connections exceeds the node's
	14	* weight.
	15	* Note that this scheduler might not be suitable for UDP because it only uses
	16	* active connections
	17	*
	18	*/
	19
	20	#define KMSG_COMPONENT "IPVS"
	21	#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
	22
	23	#include <linux/module.h>
	24	#include <linux/kernel.h>
	25
	26	#include <net/ip_vs.h>
	27
	28	/* OVF Connection scheduling */
	29	static struct ip_vs_dest *
	30	ip_vs_ovf_schedule(struct ip_vs_service svc, const struct sk_buff skb,
	31	struct ip_vs_iphdr *iph)
	32	{
	33	struct ip_vs_dest dest, h = NULL;
	34	int hw = 0, w;
	35
	36	IP_VS_DBG(6, "ip_vs_ovf_schedule(): Scheduling...\n");
	37	/* select the node with highest weight, go to next in line if active
	38	* connections exceed weight
	39	*/
	40	list_for_each_entry_rcu(dest, &svc->destinations, n_list) {
	41	w = atomic_read(&dest->weight);
	42	if ((dest->flags & IP_VS_DEST_F_OVERLOAD) \|\|
	43	atomic_read(&dest->activeconns) > w \|\|
	44	w == 0)
	45	continue;
	46	if (!h \|\| w > hw) {
	47	h = dest;
	48	hw = w;
	49	}
	50	}
	51
	52	if (h) {
	53	IP_VS_DBG_BUF(6, "OVF: server %s:%u active %d w %d\n",
	54	IP_VS_DBG_ADDR(h->af, &h->addr),
	55	ntohs(h->port),
	56	atomic_read(&h->activeconns),
	57	atomic_read(&h->weight));
	58	return h;
	59	}
	60
	61	ip_vs_scheduler_err(svc, "no destination available");
	62	return NULL;
	63	}
	64
65	static struct ip_vs_scheduler ip_vs_ovf_scheduler = {
66	.name = "ovf",
67	.refcnt = ATOMIC_INIT(0),
68	.module = THIS_MODULE,
69	.n_list = LIST_HEAD_INIT(ip_vs_ovf_scheduler.n_list),
70	.schedule = ip_vs_ovf_schedule,
71	};
72
73	static int __init ip_vs_ovf_init(void)
74	{
75	return register_ip_vs_scheduler(&ip_vs_ovf_scheduler);
76	}
77
78	static void __exit ip_vs_ovf_cleanup(void)
79	{
80	unregister_ip_vs_scheduler(&ip_vs_ovf_scheduler);
81	synchronize_rcu();
82	}
83
84	module_init(ip_vs_ovf_init);
85	module_exit(ip_vs_ovf_cleanup);
86	MODULE_LICENSE("GPL");