1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
115 lines
2.7 KiB
C
115 lines
2.7 KiB
C
/*
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* Round robin policy for multipath.
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*
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*
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* Version: $Id: multipath_rr.c,v 1.1.2.2 2004/09/16 07:42:34 elueck Exp $
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*
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* Authors: Einar Lueck <elueck@de.ibm.com><lkml@einar-lueck.de>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/config.h>
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#include <asm/system.h>
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#include <asm/uaccess.h>
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#include <linux/types.h>
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#include <linux/sched.h>
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#include <linux/errno.h>
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#include <linux/timer.h>
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#include <linux/mm.h>
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#include <linux/kernel.h>
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#include <linux/fcntl.h>
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#include <linux/stat.h>
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#include <linux/socket.h>
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#include <linux/in.h>
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#include <linux/inet.h>
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#include <linux/netdevice.h>
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#include <linux/inetdevice.h>
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#include <linux/igmp.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <linux/mroute.h>
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#include <linux/init.h>
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#include <net/ip.h>
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#include <net/protocol.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#include <net/icmp.h>
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#include <net/udp.h>
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#include <net/raw.h>
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#include <linux/notifier.h>
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#include <linux/if_arp.h>
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#include <linux/netfilter_ipv4.h>
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#include <net/ipip.h>
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#include <net/checksum.h>
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#include <net/ip_mp_alg.h>
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#define MULTIPATH_MAX_CANDIDATES 40
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static struct rtable* last_used = NULL;
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static void rr_remove(struct rtable *rt)
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{
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if (last_used == rt)
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last_used = NULL;
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}
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static void rr_select_route(const struct flowi *flp,
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struct rtable *first, struct rtable **rp)
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{
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struct rtable *nh, *result, *min_use_cand = NULL;
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int min_use = -1;
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/* if necessary and possible utilize the old alternative */
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if ((flp->flags & FLOWI_FLAG_MULTIPATHOLDROUTE) != 0 &&
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last_used != NULL) {
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result = last_used;
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goto out;
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}
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/* 1. make sure all alt. nexthops have the same GC related data
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* 2. determine the new candidate to be returned
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*/
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result = NULL;
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for (nh = rcu_dereference(first); nh;
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nh = rcu_dereference(nh->u.rt_next)) {
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if ((nh->u.dst.flags & DST_BALANCED) != 0 &&
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multipath_comparekeys(&nh->fl, flp)) {
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nh->u.dst.lastuse = jiffies;
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if (min_use == -1 || nh->u.dst.__use < min_use) {
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min_use = nh->u.dst.__use;
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min_use_cand = nh;
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}
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}
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}
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result = min_use_cand;
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if (!result)
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result = first;
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out:
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last_used = result;
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result->u.dst.__use++;
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*rp = result;
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}
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static struct ip_mp_alg_ops rr_ops = {
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.mp_alg_select_route = rr_select_route,
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.mp_alg_remove = rr_remove,
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};
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static int __init rr_init(void)
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{
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return multipath_alg_register(&rr_ops, IP_MP_ALG_RR);
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}
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static void __exit rr_exit(void)
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{
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multipath_alg_unregister(&rr_ops, IP_MP_ALG_RR);
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}
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module_init(rr_init);
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module_exit(rr_exit);
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