projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* |
| 2 | * Round robin policy for multipath. | |
| 3 | * | |
| 4 | * | |
| 5 | * Version: $Id: multipath_rr.c,v 1.1.2.2 2004/09/16 07:42:34 elueck Exp $ | |
| 6 | * | |
| 7 | * Authors: Einar Lueck <elueck@de.ibm.com><lkml@einar-lueck.de> | |
| 8 | * | |
| 9 | * This program is free software; you can redistribute it and/or | |
| 10 | * modify it under the terms of the GNU General Public License | |
| 11 | * as published by the Free Software Foundation; either version | |
| 12 | * 2 of the License, or (at your option) any later version. | |
| 13 | */ | |
| 14 | ||
| 15 | #include <linux/config.h> | |
| 16 | #include <asm/system.h> | |
| 17 | #include <asm/uaccess.h> | |
| 18 | #include <linux/types.h> | |
| 19 | #include <linux/sched.h> | |
| 20 | #include <linux/errno.h> | |
| 21 | #include <linux/timer.h> | |
| 22 | #include <linux/mm.h> | |
| 23 | #include <linux/kernel.h> | |
| 24 | #include <linux/fcntl.h> | |
| 25 | #include <linux/stat.h> | |
| 26 | #include <linux/socket.h> | |
| 27 | #include <linux/in.h> | |
| 28 | #include <linux/inet.h> | |
| 29 | #include <linux/netdevice.h> | |
| 30 | #include <linux/inetdevice.h> | |
| 31 | #include <linux/igmp.h> | |
| 32 | #include <linux/proc_fs.h> | |
| 33 | #include <linux/seq_file.h> | |
| 34 | #include <linux/mroute.h> | |
| 35 | #include <linux/init.h> | |
| 36 | #include <net/ip.h> | |
| 37 | #include <net/protocol.h> | |
| 38 | #include <linux/skbuff.h> | |
| 39 | #include <net/sock.h> | |
| 40 | #include <net/icmp.h> | |
| 41 | #include <net/udp.h> | |
| 42 | #include <net/raw.h> | |
| 43 | #include <linux/notifier.h> | |
| 44 | #include <linux/if_arp.h> | |
| 45 | #include <linux/netfilter_ipv4.h> | |
| 46 | #include <net/ipip.h> | |
| 47 | #include <net/checksum.h> | |
| 48 | #include <net/ip_mp_alg.h> | |
| 49 | ||
| 50 | #define MULTIPATH_MAX_CANDIDATES 40 | |
| 51 | ||
| 52 | static struct rtable* last_used = NULL; | |
| 53 | ||
| 54 | static void rr_remove(struct rtable *rt) | |
| 55 | { | |
| 56 | if (last_used == rt) | |
| 57 | last_used = NULL; | |
| 58 | } | |
| 59 | ||
| 60 | static void rr_select_route(const struct flowi *flp, | |
| 61 | struct rtable *first, struct rtable **rp) | |
| 62 | { | |
| 63 | struct rtable *nh, *result, *min_use_cand = NULL; | |
| 64 | int min_use = -1; | |
| 65 | ||
| 66 | /* if necessary and possible utilize the old alternative */ | |
| 67 | if ((flp->flags & FLOWI_FLAG_MULTIPATHOLDROUTE) != 0 && | |
| 68 | last_used != NULL) { | |
| 69 | result = last_used; | |
| 70 | goto out; | |
| 71 | } | |
| 72 | ||
| 73 | /* 1. make sure all alt. nexthops have the same GC related data | |
| 74 | * 2. determine the new candidate to be returned | |
| 75 | */ | |
| 76 | result = NULL; | |
| 77 | for (nh = rcu_dereference(first); nh; | |
| 78 | nh = rcu_dereference(nh->u.rt_next)) { | |
| 79 | if ((nh->u.dst.flags & DST_BALANCED) != 0 && | |
| 80 | multipath_comparekeys(&nh->fl, flp)) { | |
| 81 | nh->u.dst.lastuse = jiffies; | |
| 82 | ||
| 83 | if (min_use == -1 || nh->u.dst.__use < min_use) { | |
| 84 | min_use = nh->u.dst.__use; | |
| 85 | min_use_cand = nh; | |
| 86 | } | |
| 87 | } | |
| 88 | } | |
| 89 | result = min_use_cand; | |
| 90 | if (!result) | |
| 91 | result = first; | |
| 92 | ||
| 93 | out: | |
| 94 | last_used = result; | |
| 95 | result->u.dst.__use++; | |
| 96 | *rp = result; | |
| 97 | } | |
| 98 | ||
| 99 | static struct ip_mp_alg_ops rr_ops = { | |
| 100 | .mp_alg_select_route = rr_select_route, | |
| 101 | .mp_alg_remove = rr_remove, | |
| 102 | }; | |
| 103 | ||
| 104 | static int __init rr_init(void) | |
| 105 | { | |
| 106 | return multipath_alg_register(&rr_ops, IP_MP_ALG_RR); | |
| 107 | } | |
| 108 | ||
| 109 | static void __exit rr_exit(void) | |
| 110 | { | |
| 111 | multipath_alg_unregister(&rr_ops, IP_MP_ALG_RR); | |
| 112 | } | |
| 113 | ||
| 114 | module_init(rr_init); | |
| 115 | module_exit(rr_exit); |