mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-30 16:07:39 +00:00
6ab3d5624e
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
250 lines
5.3 KiB
C
250 lines
5.3 KiB
C
/*
|
|
* Device round robin policy for multipath.
|
|
*
|
|
*
|
|
* Version: $Id: multipath_drr.c,v 1.1.2.1 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>
|
|
|
|
struct multipath_device {
|
|
int ifi; /* interface index of device */
|
|
atomic_t usecount;
|
|
int allocated;
|
|
};
|
|
|
|
#define MULTIPATH_MAX_DEVICECANDIDATES 10
|
|
|
|
static struct multipath_device state[MULTIPATH_MAX_DEVICECANDIDATES];
|
|
static DEFINE_SPINLOCK(state_lock);
|
|
|
|
static int inline __multipath_findslot(void)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < MULTIPATH_MAX_DEVICECANDIDATES; i++) {
|
|
if (state[i].allocated == 0)
|
|
return i;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
static int inline __multipath_finddev(int ifindex)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < MULTIPATH_MAX_DEVICECANDIDATES; i++) {
|
|
if (state[i].allocated != 0 &&
|
|
state[i].ifi == ifindex)
|
|
return i;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
static int drr_dev_event(struct notifier_block *this,
|
|
unsigned long event, void *ptr)
|
|
{
|
|
struct net_device *dev = ptr;
|
|
int devidx;
|
|
|
|
switch (event) {
|
|
case NETDEV_UNREGISTER:
|
|
case NETDEV_DOWN:
|
|
spin_lock_bh(&state_lock);
|
|
|
|
devidx = __multipath_finddev(dev->ifindex);
|
|
if (devidx != -1) {
|
|
state[devidx].allocated = 0;
|
|
state[devidx].ifi = 0;
|
|
atomic_set(&state[devidx].usecount, 0);
|
|
}
|
|
|
|
spin_unlock_bh(&state_lock);
|
|
break;
|
|
};
|
|
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
static struct notifier_block drr_dev_notifier = {
|
|
.notifier_call = drr_dev_event,
|
|
};
|
|
|
|
|
|
static void drr_safe_inc(atomic_t *usecount)
|
|
{
|
|
int n;
|
|
|
|
atomic_inc(usecount);
|
|
|
|
n = atomic_read(usecount);
|
|
if (n <= 0) {
|
|
int i;
|
|
|
|
spin_lock_bh(&state_lock);
|
|
|
|
for (i = 0; i < MULTIPATH_MAX_DEVICECANDIDATES; i++)
|
|
atomic_set(&state[i].usecount, 0);
|
|
|
|
spin_unlock_bh(&state_lock);
|
|
}
|
|
}
|
|
|
|
static void drr_select_route(const struct flowi *flp,
|
|
struct rtable *first, struct rtable **rp)
|
|
{
|
|
struct rtable *nh, *result, *cur_min;
|
|
int min_usecount = -1;
|
|
int devidx = -1;
|
|
int cur_min_devidx = -1;
|
|
|
|
/* 1. make sure all alt. nexthops have the same GC related data */
|
|
/* 2. determine the new candidate to be returned */
|
|
result = NULL;
|
|
cur_min = 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)) {
|
|
int nh_ifidx = nh->u.dst.dev->ifindex;
|
|
|
|
nh->u.dst.lastuse = jiffies;
|
|
nh->u.dst.__use++;
|
|
if (result != NULL)
|
|
continue;
|
|
|
|
/* search for the output interface */
|
|
|
|
/* this is not SMP safe, only add/remove are
|
|
* SMP safe as wrong usecount updates have no big
|
|
* impact
|
|
*/
|
|
devidx = __multipath_finddev(nh_ifidx);
|
|
if (devidx == -1) {
|
|
/* add the interface to the array
|
|
* SMP safe
|
|
*/
|
|
spin_lock_bh(&state_lock);
|
|
|
|
/* due to SMP: search again */
|
|
devidx = __multipath_finddev(nh_ifidx);
|
|
if (devidx == -1) {
|
|
/* add entry for device */
|
|
devidx = __multipath_findslot();
|
|
if (devidx == -1) {
|
|
/* unlikely but possible */
|
|
continue;
|
|
}
|
|
|
|
state[devidx].allocated = 1;
|
|
state[devidx].ifi = nh_ifidx;
|
|
atomic_set(&state[devidx].usecount, 0);
|
|
min_usecount = 0;
|
|
}
|
|
|
|
spin_unlock_bh(&state_lock);
|
|
}
|
|
|
|
if (min_usecount == 0) {
|
|
/* if the device has not been used it is
|
|
* the primary target
|
|
*/
|
|
drr_safe_inc(&state[devidx].usecount);
|
|
result = nh;
|
|
} else {
|
|
int count =
|
|
atomic_read(&state[devidx].usecount);
|
|
|
|
if (min_usecount == -1 ||
|
|
count < min_usecount) {
|
|
cur_min = nh;
|
|
cur_min_devidx = devidx;
|
|
min_usecount = count;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (!result) {
|
|
if (cur_min) {
|
|
drr_safe_inc(&state[cur_min_devidx].usecount);
|
|
result = cur_min;
|
|
} else {
|
|
result = first;
|
|
}
|
|
}
|
|
|
|
*rp = result;
|
|
}
|
|
|
|
static struct ip_mp_alg_ops drr_ops = {
|
|
.mp_alg_select_route = drr_select_route,
|
|
};
|
|
|
|
static int __init drr_init(void)
|
|
{
|
|
int err = register_netdevice_notifier(&drr_dev_notifier);
|
|
|
|
if (err)
|
|
return err;
|
|
|
|
err = multipath_alg_register(&drr_ops, IP_MP_ALG_DRR);
|
|
if (err)
|
|
goto fail;
|
|
|
|
return 0;
|
|
|
|
fail:
|
|
unregister_netdevice_notifier(&drr_dev_notifier);
|
|
return err;
|
|
}
|
|
|
|
static void __exit drr_exit(void)
|
|
{
|
|
unregister_netdevice_notifier(&drr_dev_notifier);
|
|
multipath_alg_unregister(&drr_ops, IP_MP_ALG_DRR);
|
|
}
|
|
|
|
module_init(drr_init);
|
|
module_exit(drr_exit);
|
|
MODULE_LICENSE("GPL");
|