linux/net/ipv4/multipath_rr.c

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/*
* Round robin policy for multipath.
*
*
* Version: $Id: multipath_rr.c,v 1.1.2.2 2004/09/16 07:42:34 elueck Exp $
*
* Authors: Einar Lueck <elueck@de.ibm.com><lkml@einar-lueck.de>
*
* 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.
*/
#include <asm/system.h>
#include <asm/uaccess.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/fcntl.h>
#include <linux/stat.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/igmp.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/module.h>
#include <linux/mroute.h>
#include <linux/init.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/icmp.h>
#include <net/udp.h>
#include <net/raw.h>
#include <linux/notifier.h>
#include <linux/if_arp.h>
#include <linux/netfilter_ipv4.h>
#include <net/ipip.h>
#include <net/checksum.h>
#include <net/ip_mp_alg.h>
static void rr_select_route(const struct flowi *flp,
struct rtable *first, struct rtable **rp)
{
struct rtable *nh, *result, *min_use_cand = NULL;
int min_use = -1;
/* 1. make sure all alt. nexthops have the same GC related data
* 2. determine the new candidate to be returned
*/
result = NULL;
for (nh = rcu_dereference(first); nh;
nh = rcu_dereference(nh->u.rt_next)) {
if ((nh->u.dst.flags & DST_BALANCED) != 0 &&
multipath_comparekeys(&nh->fl, flp)) {
nh->u.dst.lastuse = jiffies;
if (min_use == -1 || nh->u.dst.__use < min_use) {
min_use = nh->u.dst.__use;
min_use_cand = nh;
}
}
}
result = min_use_cand;
if (!result)
result = first;
result->u.dst.__use++;
*rp = result;
}
static struct ip_mp_alg_ops rr_ops = {
.mp_alg_select_route = rr_select_route,
};
static int __init rr_init(void)
{
return multipath_alg_register(&rr_ops, IP_MP_ALG_RR);
}
static void __exit rr_exit(void)
{
multipath_alg_unregister(&rr_ops, IP_MP_ALG_RR);
}
module_init(rr_init);
module_exit(rr_exit);
MODULE_LICENSE("GPL");