diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /net/ipv4/multipath_drr.c |
Linux-2.6.12-rc2v2.6.12-rc2
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!
Diffstat (limited to 'net/ipv4/multipath_drr.c')
-rw-r--r-- | net/ipv4/multipath_drr.c | 265 |
1 files changed, 265 insertions, 0 deletions
diff --git a/net/ipv4/multipath_drr.c b/net/ipv4/multipath_drr.c new file mode 100644 index 000000000000..9349686131fc --- /dev/null +++ b/net/ipv4/multipath_drr.c | |||
@@ -0,0 +1,265 @@ | |||
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 <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 | struct multipath_device { | ||
51 | int ifi; /* interface index of device */ | ||
52 | atomic_t usecount; | ||
53 | int allocated; | ||
54 | }; | ||
55 | |||
56 | #define MULTIPATH_MAX_DEVICECANDIDATES 10 | ||
57 | |||
58 | static struct multipath_device state[MULTIPATH_MAX_DEVICECANDIDATES]; | ||
59 | static DEFINE_SPINLOCK(state_lock); | ||
60 | static struct rtable *last_selection = NULL; | ||
61 | |||
62 | static int inline __multipath_findslot(void) | ||
63 | { | ||
64 | int i; | ||
65 | |||
66 | for (i = 0; i < MULTIPATH_MAX_DEVICECANDIDATES; i++) { | ||
67 | if (state[i].allocated == 0) | ||
68 | return i; | ||
69 | } | ||
70 | return -1; | ||
71 | } | ||
72 | |||
73 | static int inline __multipath_finddev(int ifindex) | ||
74 | { | ||
75 | int i; | ||
76 | |||
77 | for (i = 0; i < MULTIPATH_MAX_DEVICECANDIDATES; i++) { | ||
78 | if (state[i].allocated != 0 && | ||
79 | state[i].ifi == ifindex) | ||
80 | return i; | ||
81 | } | ||
82 | return -1; | ||
83 | } | ||
84 | |||
85 | static int drr_dev_event(struct notifier_block *this, | ||
86 | unsigned long event, void *ptr) | ||
87 | { | ||
88 | struct net_device *dev = ptr; | ||
89 | int devidx; | ||
90 | |||
91 | switch (event) { | ||
92 | case NETDEV_UNREGISTER: | ||
93 | case NETDEV_DOWN: | ||
94 | spin_lock_bh(&state_lock); | ||
95 | |||
96 | devidx = __multipath_finddev(dev->ifindex); | ||
97 | if (devidx != -1) { | ||
98 | state[devidx].allocated = 0; | ||
99 | state[devidx].ifi = 0; | ||
100 | atomic_set(&state[devidx].usecount, 0); | ||
101 | } | ||
102 | |||
103 | spin_unlock_bh(&state_lock); | ||
104 | break; | ||
105 | }; | ||
106 | |||
107 | return NOTIFY_DONE; | ||
108 | } | ||
109 | |||
110 | struct notifier_block drr_dev_notifier = { | ||
111 | .notifier_call = drr_dev_event, | ||
112 | }; | ||
113 | |||
114 | static void drr_remove(struct rtable *rt) | ||
115 | { | ||
116 | if (last_selection == rt) | ||
117 | last_selection = NULL; | ||
118 | } | ||
119 | |||
120 | static void drr_safe_inc(atomic_t *usecount) | ||
121 | { | ||
122 | int n; | ||
123 | |||
124 | atomic_inc(usecount); | ||
125 | |||
126 | n = atomic_read(usecount); | ||
127 | if (n <= 0) { | ||
128 | int i; | ||
129 | |||
130 | spin_lock_bh(&state_lock); | ||
131 | |||
132 | for (i = 0; i < MULTIPATH_MAX_DEVICECANDIDATES; i++) | ||
133 | atomic_set(&state[i].usecount, 0); | ||
134 | |||
135 | spin_unlock_bh(&state_lock); | ||
136 | } | ||
137 | } | ||
138 | |||
139 | static void drr_select_route(const struct flowi *flp, | ||
140 | struct rtable *first, struct rtable **rp) | ||
141 | { | ||
142 | struct rtable *nh, *result, *cur_min; | ||
143 | int min_usecount = -1; | ||
144 | int devidx = -1; | ||
145 | int cur_min_devidx = -1; | ||
146 | |||
147 | /* if necessary and possible utilize the old alternative */ | ||
148 | if ((flp->flags & FLOWI_FLAG_MULTIPATHOLDROUTE) != 0 && | ||
149 | last_selection != NULL) { | ||
150 | result = last_selection; | ||
151 | *rp = result; | ||
152 | return; | ||
153 | } | ||
154 | |||
155 | /* 1. make sure all alt. nexthops have the same GC related data */ | ||
156 | /* 2. determine the new candidate to be returned */ | ||
157 | result = NULL; | ||
158 | cur_min = NULL; | ||
159 | for (nh = rcu_dereference(first); nh; | ||
160 | nh = rcu_dereference(nh->u.rt_next)) { | ||
161 | if ((nh->u.dst.flags & DST_BALANCED) != 0 && | ||
162 | multipath_comparekeys(&nh->fl, flp)) { | ||
163 | int nh_ifidx = nh->u.dst.dev->ifindex; | ||
164 | |||
165 | nh->u.dst.lastuse = jiffies; | ||
166 | nh->u.dst.__use++; | ||
167 | if (result != NULL) | ||
168 | continue; | ||
169 | |||
170 | /* search for the output interface */ | ||
171 | |||
172 | /* this is not SMP safe, only add/remove are | ||
173 | * SMP safe as wrong usecount updates have no big | ||
174 | * impact | ||
175 | */ | ||
176 | devidx = __multipath_finddev(nh_ifidx); | ||
177 | if (devidx == -1) { | ||
178 | /* add the interface to the array | ||
179 | * SMP safe | ||
180 | */ | ||
181 | spin_lock_bh(&state_lock); | ||
182 | |||
183 | /* due to SMP: search again */ | ||
184 | devidx = __multipath_finddev(nh_ifidx); | ||
185 | if (devidx == -1) { | ||
186 | /* add entry for device */ | ||
187 | devidx = __multipath_findslot(); | ||
188 | if (devidx == -1) { | ||
189 | /* unlikely but possible */ | ||
190 | continue; | ||
191 | } | ||
192 | |||
193 | state[devidx].allocated = 1; | ||
194 | state[devidx].ifi = nh_ifidx; | ||
195 | atomic_set(&state[devidx].usecount, 0); | ||
196 | min_usecount = 0; | ||
197 | } | ||
198 | |||
199 | spin_unlock_bh(&state_lock); | ||
200 | } | ||
201 | |||
202 | if (min_usecount == 0) { | ||
203 | /* if the device has not been used it is | ||
204 | * the primary target | ||
205 | */ | ||
206 | drr_safe_inc(&state[devidx].usecount); | ||
207 | result = nh; | ||
208 | } else { | ||
209 | int count = | ||
210 | atomic_read(&state[devidx].usecount); | ||
211 | |||
212 | if (min_usecount == -1 || | ||
213 | count < min_usecount) { | ||
214 | cur_min = nh; | ||
215 | cur_min_devidx = devidx; | ||
216 | min_usecount = count; | ||
217 | } | ||
218 | } | ||
219 | } | ||
220 | } | ||
221 | |||
222 | if (!result) { | ||
223 | if (cur_min) { | ||
224 | drr_safe_inc(&state[cur_min_devidx].usecount); | ||
225 | result = cur_min; | ||
226 | } else { | ||
227 | result = first; | ||
228 | } | ||
229 | } | ||
230 | |||
231 | *rp = result; | ||
232 | last_selection = result; | ||
233 | } | ||
234 | |||
235 | static struct ip_mp_alg_ops drr_ops = { | ||
236 | .mp_alg_select_route = drr_select_route, | ||
237 | .mp_alg_remove = drr_remove, | ||
238 | }; | ||
239 | |||
240 | static int __init drr_init(void) | ||
241 | { | ||
242 | int err = register_netdevice_notifier(&drr_dev_notifier); | ||
243 | |||
244 | if (err) | ||
245 | return err; | ||
246 | |||
247 | err = multipath_alg_register(&drr_ops, IP_MP_ALG_RR); | ||
248 | if (err) | ||
249 | goto fail; | ||
250 | |||
251 | return 0; | ||
252 | |||
253 | fail: | ||
254 | unregister_netdevice_notifier(&drr_dev_notifier); | ||
255 | return err; | ||
256 | } | ||
257 | |||
258 | static void __exit drr_exit(void) | ||
259 | { | ||
260 | unregister_netdevice_notifier(&drr_dev_notifier); | ||
261 | multipath_alg_unregister(&drr_ops, IP_MP_ALG_DRR); | ||
262 | } | ||
263 | |||
264 | module_init(drr_init); | ||
265 | module_exit(drr_exit); | ||