blob: 19991175fdeb4bca0f2e357ae7dfa5545dc72371 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* flow.c: Generic flow cache.
2 *
3 * Copyright (C) 2003 Alexey N. Kuznetsov (kuznet@ms2.inr.ac.ru)
4 * Copyright (C) 2003 David S. Miller (davem@redhat.com)
5 */
6
7#include <linux/kernel.h>
8#include <linux/module.h>
9#include <linux/list.h>
10#include <linux/jhash.h>
11#include <linux/interrupt.h>
12#include <linux/mm.h>
13#include <linux/random.h>
14#include <linux/init.h>
15#include <linux/slab.h>
16#include <linux/smp.h>
17#include <linux/completion.h>
18#include <linux/percpu.h>
19#include <linux/bitops.h>
20#include <linux/notifier.h>
21#include <linux/cpu.h>
22#include <linux/cpumask.h>
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -080023#include <linux/mutex.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024#include <net/flow.h>
25#include <asm/atomic.h>
Trent Jaegerdf718372005-12-13 23:12:27 -080026#include <linux/security.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027
28struct flow_cache_entry {
29 struct flow_cache_entry *next;
30 u16 family;
31 u8 dir;
Linus Torvalds1da177e2005-04-16 15:20:36 -070032 u32 genid;
Eric Dumazetdd5a1842008-02-07 23:30:42 -080033 struct flowi key;
Linus Torvalds1da177e2005-04-16 15:20:36 -070034 void *object;
35 atomic_t *object_ref;
36};
37
38atomic_t flow_cache_genid = ATOMIC_INIT(0);
39
40static u32 flow_hash_shift;
41#define flow_hash_size (1 << flow_hash_shift)
42static DEFINE_PER_CPU(struct flow_cache_entry **, flow_tables) = { NULL };
43
44#define flow_table(cpu) (per_cpu(flow_tables, cpu))
45
Christoph Lametere18b8902006-12-06 20:33:20 -080046static struct kmem_cache *flow_cachep __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -070047
48static int flow_lwm, flow_hwm;
49
50struct flow_percpu_info {
51 int hash_rnd_recalc;
52 u32 hash_rnd;
53 int count;
Eric Dumazet5f58a5c2008-02-07 18:03:18 -080054};
Linus Torvalds1da177e2005-04-16 15:20:36 -070055static DEFINE_PER_CPU(struct flow_percpu_info, flow_hash_info) = { 0 };
56
57#define flow_hash_rnd_recalc(cpu) \
58 (per_cpu(flow_hash_info, cpu).hash_rnd_recalc)
59#define flow_hash_rnd(cpu) \
60 (per_cpu(flow_hash_info, cpu).hash_rnd)
61#define flow_count(cpu) \
62 (per_cpu(flow_hash_info, cpu).count)
63
64static struct timer_list flow_hash_rnd_timer;
65
66#define FLOW_HASH_RND_PERIOD (10 * 60 * HZ)
67
68struct flow_flush_info {
69 atomic_t cpuleft;
70 struct completion completion;
71};
72static DEFINE_PER_CPU(struct tasklet_struct, flow_flush_tasklets) = { NULL };
73
74#define flow_flush_tasklet(cpu) (&per_cpu(flow_flush_tasklets, cpu))
75
76static void flow_cache_new_hashrnd(unsigned long arg)
77{
78 int i;
79
KAMEZAWA Hiroyuki6f912042006-04-10 22:52:50 -070080 for_each_possible_cpu(i)
Linus Torvalds1da177e2005-04-16 15:20:36 -070081 flow_hash_rnd_recalc(i) = 1;
82
83 flow_hash_rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
84 add_timer(&flow_hash_rnd_timer);
85}
86
James Morris134b0fc2006-10-05 15:42:27 -050087static void flow_entry_kill(int cpu, struct flow_cache_entry *fle)
88{
89 if (fle->object)
90 atomic_dec(fle->object_ref);
91 kmem_cache_free(flow_cachep, fle);
92 flow_count(cpu)--;
93}
94
Linus Torvalds1da177e2005-04-16 15:20:36 -070095static void __flow_cache_shrink(int cpu, int shrink_to)
96{
97 struct flow_cache_entry *fle, **flp;
98 int i;
99
100 for (i = 0; i < flow_hash_size; i++) {
101 int k = 0;
102
103 flp = &flow_table(cpu)[i];
104 while ((fle = *flp) != NULL && k < shrink_to) {
105 k++;
106 flp = &fle->next;
107 }
108 while ((fle = *flp) != NULL) {
109 *flp = fle->next;
James Morris134b0fc2006-10-05 15:42:27 -0500110 flow_entry_kill(cpu, fle);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 }
112 }
113}
114
115static void flow_cache_shrink(int cpu)
116{
117 int shrink_to = flow_lwm / flow_hash_size;
118
119 __flow_cache_shrink(cpu, shrink_to);
120}
121
122static void flow_new_hash_rnd(int cpu)
123{
124 get_random_bytes(&flow_hash_rnd(cpu), sizeof(u32));
125 flow_hash_rnd_recalc(cpu) = 0;
126
127 __flow_cache_shrink(cpu, 0);
128}
129
130static u32 flow_hash_code(struct flowi *key, int cpu)
131{
132 u32 *k = (u32 *) key;
133
134 return (jhash2(k, (sizeof(*key) / sizeof(u32)), flow_hash_rnd(cpu)) &
135 (flow_hash_size - 1));
136}
137
138#if (BITS_PER_LONG == 64)
139typedef u64 flow_compare_t;
140#else
141typedef u32 flow_compare_t;
142#endif
143
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144/* I hear what you're saying, use memcmp. But memcmp cannot make
145 * important assumptions that we can here, such as alignment and
146 * constant size.
147 */
148static int flow_key_compare(struct flowi *key1, struct flowi *key2)
149{
150 flow_compare_t *k1, *k1_lim, *k2;
151 const int n_elem = sizeof(struct flowi) / sizeof(flow_compare_t);
152
Pavel Emelyanovf0fe91d2007-10-23 21:15:21 -0700153 BUILD_BUG_ON(sizeof(struct flowi) % sizeof(flow_compare_t));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154
155 k1 = (flow_compare_t *) key1;
156 k1_lim = k1 + n_elem;
157
158 k2 = (flow_compare_t *) key2;
159
160 do {
161 if (*k1++ != *k2++)
162 return 1;
163 } while (k1 < k1_lim);
164
165 return 0;
166}
167
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700168void *flow_cache_lookup(struct flowi *key, u16 family, u8 dir,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 flow_resolve_t resolver)
170{
171 struct flow_cache_entry *fle, **head;
172 unsigned int hash;
173 int cpu;
174
175 local_bh_disable();
176 cpu = smp_processor_id();
177
178 fle = NULL;
179 /* Packet really early in init? Making flow_cache_init a
180 * pre-smp initcall would solve this. --RR */
181 if (!flow_table(cpu))
182 goto nocache;
183
184 if (flow_hash_rnd_recalc(cpu))
185 flow_new_hash_rnd(cpu);
186 hash = flow_hash_code(key, cpu);
187
188 head = &flow_table(cpu)[hash];
189 for (fle = *head; fle; fle = fle->next) {
190 if (fle->family == family &&
191 fle->dir == dir &&
192 flow_key_compare(key, &fle->key) == 0) {
193 if (fle->genid == atomic_read(&flow_cache_genid)) {
194 void *ret = fle->object;
195
196 if (ret)
197 atomic_inc(fle->object_ref);
198 local_bh_enable();
199
200 return ret;
201 }
202 break;
203 }
204 }
205
206 if (!fle) {
207 if (flow_count(cpu) > flow_hwm)
208 flow_cache_shrink(cpu);
209
Christoph Lameter54e6ecb2006-12-06 20:33:16 -0800210 fle = kmem_cache_alloc(flow_cachep, GFP_ATOMIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 if (fle) {
212 fle->next = *head;
213 *head = fle;
214 fle->family = family;
215 fle->dir = dir;
216 memcpy(&fle->key, key, sizeof(*key));
217 fle->object = NULL;
218 flow_count(cpu)++;
219 }
220 }
221
222nocache:
223 {
James Morris134b0fc2006-10-05 15:42:27 -0500224 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 void *obj;
226 atomic_t *obj_ref;
227
James Morris134b0fc2006-10-05 15:42:27 -0500228 err = resolver(key, family, dir, &obj, &obj_ref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229
Herbert Xue0e8f1c2007-01-10 22:06:32 -0800230 if (fle && !err) {
231 fle->genid = atomic_read(&flow_cache_genid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232
Herbert Xue0e8f1c2007-01-10 22:06:32 -0800233 if (fle->object)
234 atomic_dec(fle->object_ref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235
Herbert Xue0e8f1c2007-01-10 22:06:32 -0800236 fle->object = obj;
237 fle->object_ref = obj_ref;
238 if (obj)
239 atomic_inc(fle->object_ref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 }
241 local_bh_enable();
242
James Morris134b0fc2006-10-05 15:42:27 -0500243 if (err)
244 obj = ERR_PTR(err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 return obj;
246 }
247}
248
249static void flow_cache_flush_tasklet(unsigned long data)
250{
251 struct flow_flush_info *info = (void *)data;
252 int i;
253 int cpu;
254
255 cpu = smp_processor_id();
256 for (i = 0; i < flow_hash_size; i++) {
257 struct flow_cache_entry *fle;
258
259 fle = flow_table(cpu)[i];
260 for (; fle; fle = fle->next) {
261 unsigned genid = atomic_read(&flow_cache_genid);
262
263 if (!fle->object || fle->genid == genid)
264 continue;
265
266 fle->object = NULL;
267 atomic_dec(fle->object_ref);
268 }
269 }
270
271 if (atomic_dec_and_test(&info->cpuleft))
272 complete(&info->completion);
273}
274
275static void flow_cache_flush_per_cpu(void *) __attribute__((__unused__));
276static void flow_cache_flush_per_cpu(void *data)
277{
278 struct flow_flush_info *info = data;
279 int cpu;
280 struct tasklet_struct *tasklet;
281
282 cpu = smp_processor_id();
283
284 tasklet = flow_flush_tasklet(cpu);
285 tasklet->data = (unsigned long)info;
286 tasklet_schedule(tasklet);
287}
288
289void flow_cache_flush(void)
290{
291 struct flow_flush_info info;
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800292 static DEFINE_MUTEX(flow_flush_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293
294 /* Don't want cpus going down or up during this. */
Gautham R Shenoy86ef5c92008-01-25 21:08:02 +0100295 get_online_cpus();
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800296 mutex_lock(&flow_flush_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 atomic_set(&info.cpuleft, num_online_cpus());
298 init_completion(&info.completion);
299
300 local_bh_disable();
301 smp_call_function(flow_cache_flush_per_cpu, &info, 1, 0);
302 flow_cache_flush_tasklet((unsigned long)&info);
303 local_bh_enable();
304
305 wait_for_completion(&info.completion);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800306 mutex_unlock(&flow_flush_sem);
Gautham R Shenoy86ef5c92008-01-25 21:08:02 +0100307 put_online_cpus();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308}
309
310static void __devinit flow_cache_cpu_prepare(int cpu)
311{
312 struct tasklet_struct *tasklet;
313 unsigned long order;
314
315 for (order = 0;
316 (PAGE_SIZE << order) <
317 (sizeof(struct flow_cache_entry *)*flow_hash_size);
318 order++)
319 /* NOTHING */;
320
321 flow_table(cpu) = (struct flow_cache_entry **)
Andrew Morton77d04bd2006-04-07 14:52:59 -0700322 __get_free_pages(GFP_KERNEL|__GFP_ZERO, order);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 if (!flow_table(cpu))
324 panic("NET: failed to allocate flow cache order %lu\n", order);
325
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 flow_hash_rnd_recalc(cpu) = 1;
327 flow_count(cpu) = 0;
328
329 tasklet = flow_flush_tasklet(cpu);
330 tasklet_init(tasklet, flow_cache_flush_tasklet, 0);
331}
332
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333static int flow_cache_cpu(struct notifier_block *nfb,
334 unsigned long action,
335 void *hcpu)
336{
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -0700337 if (action == CPU_DEAD || action == CPU_DEAD_FROZEN)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 __flow_cache_shrink((unsigned long)hcpu, 0);
339 return NOTIFY_OK;
340}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341
342static int __init flow_cache_init(void)
343{
344 int i;
345
346 flow_cachep = kmem_cache_create("flow_cache",
347 sizeof(struct flow_cache_entry),
Eric Dumazetdd5a1842008-02-07 23:30:42 -0800348 0, SLAB_PANIC,
Paul Mundt20c2df82007-07-20 10:11:58 +0900349 NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 flow_hash_shift = 10;
351 flow_lwm = 2 * flow_hash_size;
352 flow_hwm = 4 * flow_hash_size;
353
Pavel Emelyanovb24b8a22008-01-23 21:20:07 -0800354 setup_timer(&flow_hash_rnd_timer, flow_cache_new_hashrnd, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 flow_hash_rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
356 add_timer(&flow_hash_rnd_timer);
357
KAMEZAWA Hiroyuki6f912042006-04-10 22:52:50 -0700358 for_each_possible_cpu(i)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 flow_cache_cpu_prepare(i);
360
361 hotcpu_notifier(flow_cache_cpu, 0);
362 return 0;
363}
364
365module_init(flow_cache_init);
366
367EXPORT_SYMBOL(flow_cache_genid);
368EXPORT_SYMBOL(flow_cache_lookup);