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authorDavid S. Miller <davem@sunset.davemloft.net>2007-06-10 20:22:39 -0400
committerDavid S. Miller <davem@sunset.davemloft.net>2007-07-11 01:05:57 -0400
commite06e7c615877026544ad7f8b309d1a3706410383 (patch)
treeeb087b49279e6db492039a5d684ca9acb13265a3 /net/ipv4/multipath_drr.c
parent4eb6bf6bfb580afaf1e1a1d30cba17a078530cf4 (diff)
[IPV4]: The scheduled removal of multipath cached routing support.
With help from Chris Wedgwood. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/multipath_drr.c')
-rw-r--r--net/ipv4/multipath_drr.c249
1 files changed, 0 insertions, 249 deletions
diff --git a/net/ipv4/multipath_drr.c b/net/ipv4/multipath_drr.c
deleted file mode 100644
index b03c5ca2c823..000000000000
--- a/net/ipv4/multipath_drr.c
+++ /dev/null
@@ -1,249 +0,0 @@
1/*
2 * Device round robin policy for multipath.
3 *
4 *
5 * Version: $Id: multipath_drr.c,v 1.1.2.1 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 <asm/system.h>
16#include <asm/uaccess.h>
17#include <linux/types.h>
18#include <linux/errno.h>
19#include <linux/timer.h>
20#include <linux/mm.h>
21#include <linux/kernel.h>
22#include <linux/fcntl.h>
23#include <linux/stat.h>
24#include <linux/socket.h>
25#include <linux/in.h>
26#include <linux/inet.h>
27#include <linux/netdevice.h>
28#include <linux/inetdevice.h>
29#include <linux/igmp.h>
30#include <linux/proc_fs.h>
31#include <linux/seq_file.h>
32#include <linux/module.h>
33#include <linux/mroute.h>
34#include <linux/init.h>
35#include <net/ip.h>
36#include <net/protocol.h>
37#include <linux/skbuff.h>
38#include <net/sock.h>
39#include <net/icmp.h>
40#include <net/udp.h>
41#include <net/raw.h>
42#include <linux/notifier.h>
43#include <linux/if_arp.h>
44#include <linux/netfilter_ipv4.h>
45#include <net/ipip.h>
46#include <net/checksum.h>
47#include <net/ip_mp_alg.h>
48
49struct multipath_device {
50 int ifi; /* interface index of device */
51 atomic_t usecount;
52 int allocated;
53};
54
55#define MULTIPATH_MAX_DEVICECANDIDATES 10
56
57static struct multipath_device state[MULTIPATH_MAX_DEVICECANDIDATES];
58static DEFINE_SPINLOCK(state_lock);
59
60static int inline __multipath_findslot(void)
61{
62 int i;
63
64 for (i = 0; i < MULTIPATH_MAX_DEVICECANDIDATES; i++) {
65 if (state[i].allocated == 0)
66 return i;
67 }
68 return -1;
69}
70
71static int inline __multipath_finddev(int ifindex)
72{
73 int i;
74
75 for (i = 0; i < MULTIPATH_MAX_DEVICECANDIDATES; i++) {
76 if (state[i].allocated != 0 &&
77 state[i].ifi == ifindex)
78 return i;
79 }
80 return -1;
81}
82
83static int drr_dev_event(struct notifier_block *this,
84 unsigned long event, void *ptr)
85{
86 struct net_device *dev = ptr;
87 int devidx;
88
89 switch (event) {
90 case NETDEV_UNREGISTER:
91 case NETDEV_DOWN:
92 spin_lock_bh(&state_lock);
93
94 devidx = __multipath_finddev(dev->ifindex);
95 if (devidx != -1) {
96 state[devidx].allocated = 0;
97 state[devidx].ifi = 0;
98 atomic_set(&state[devidx].usecount, 0);
99 }
100
101 spin_unlock_bh(&state_lock);
102 break;
103 }
104
105 return NOTIFY_DONE;
106}
107
108static struct notifier_block drr_dev_notifier = {
109 .notifier_call = drr_dev_event,
110};
111
112
113static void drr_safe_inc(atomic_t *usecount)
114{
115 int n;
116
117 atomic_inc(usecount);
118
119 n = atomic_read(usecount);
120 if (n <= 0) {
121 int i;
122
123 spin_lock_bh(&state_lock);
124
125 for (i = 0; i < MULTIPATH_MAX_DEVICECANDIDATES; i++)
126 atomic_set(&state[i].usecount, 0);
127
128 spin_unlock_bh(&state_lock);
129 }
130}
131
132static void drr_select_route(const struct flowi *flp,
133 struct rtable *first, struct rtable **rp)
134{
135 struct rtable *nh, *result, *cur_min;
136 int min_usecount = -1;
137 int devidx = -1;
138 int cur_min_devidx = -1;
139
140 /* 1. make sure all alt. nexthops have the same GC related data */
141 /* 2. determine the new candidate to be returned */
142 result = NULL;
143 cur_min = NULL;
144 for (nh = rcu_dereference(first); nh;
145 nh = rcu_dereference(nh->u.dst.rt_next)) {
146 if ((nh->u.dst.flags & DST_BALANCED) != 0 &&
147 multipath_comparekeys(&nh->fl, flp)) {
148 int nh_ifidx = nh->u.dst.dev->ifindex;
149
150 nh->u.dst.lastuse = jiffies;
151 nh->u.dst.__use++;
152 if (result != NULL)
153 continue;
154
155 /* search for the output interface */
156
157 /* this is not SMP safe, only add/remove are
158 * SMP safe as wrong usecount updates have no big
159 * impact
160 */
161 devidx = __multipath_finddev(nh_ifidx);
162 if (devidx == -1) {
163 /* add the interface to the array
164 * SMP safe
165 */
166 spin_lock_bh(&state_lock);
167
168 /* due to SMP: search again */
169 devidx = __multipath_finddev(nh_ifidx);
170 if (devidx == -1) {
171 /* add entry for device */
172 devidx = __multipath_findslot();
173 if (devidx == -1) {
174 /* unlikely but possible */
175 continue;
176 }
177
178 state[devidx].allocated = 1;
179 state[devidx].ifi = nh_ifidx;
180 atomic_set(&state[devidx].usecount, 0);
181 min_usecount = 0;
182 }
183
184 spin_unlock_bh(&state_lock);
185 }
186
187 if (min_usecount == 0) {
188 /* if the device has not been used it is
189 * the primary target
190 */
191 drr_safe_inc(&state[devidx].usecount);
192 result = nh;
193 } else {
194 int count =
195 atomic_read(&state[devidx].usecount);
196
197 if (min_usecount == -1 ||
198 count < min_usecount) {
199 cur_min = nh;
200 cur_min_devidx = devidx;
201 min_usecount = count;
202 }
203 }
204 }
205 }
206
207 if (!result) {
208 if (cur_min) {
209 drr_safe_inc(&state[cur_min_devidx].usecount);
210 result = cur_min;
211 } else {
212 result = first;
213 }
214 }
215
216 *rp = result;
217}
218
219static struct ip_mp_alg_ops drr_ops = {
220 .mp_alg_select_route = drr_select_route,
221};
222
223static int __init drr_init(void)
224{
225 int err = register_netdevice_notifier(&drr_dev_notifier);
226
227 if (err)
228 return err;
229
230 err = multipath_alg_register(&drr_ops, IP_MP_ALG_DRR);
231 if (err)
232 goto fail;
233
234 return 0;
235
236fail:
237 unregister_netdevice_notifier(&drr_dev_notifier);
238 return err;
239}
240
241static void __exit drr_exit(void)
242{
243 unregister_netdevice_notifier(&drr_dev_notifier);
244 multipath_alg_unregister(&drr_ops, IP_MP_ALG_DRR);
245}
246
247module_init(drr_init);
248module_exit(drr_exit);
249MODULE_LICENSE("GPL");
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