| /* |
| * 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 <linux/config.h> |
| #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/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> |
| |
| #define MULTIPATH_MAX_CANDIDATES 40 |
| |
| static struct rtable* last_used = NULL; |
| |
| static void rr_remove(struct rtable *rt) |
| { |
| if (last_used == rt) |
| last_used = NULL; |
| } |
| |
| 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; |
| |
| /* if necessary and possible utilize the old alternative */ |
| if ((flp->flags & FLOWI_FLAG_MULTIPATHOLDROUTE) != 0 && |
| last_used != NULL) { |
| result = last_used; |
| goto out; |
| } |
| |
| /* 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; |
| |
| out: |
| last_used = result; |
| result->u.dst.__use++; |
| *rp = result; |
| } |
| |
| static struct ip_mp_alg_ops rr_ops = { |
| .mp_alg_select_route = rr_select_route, |
| .mp_alg_remove = rr_remove, |
| }; |
| |
| 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); |