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42#define KMSG_COMPONENT "IPVS"
43#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
44
45#include <linux/ip.h>
46#include <linux/module.h>
47#include <linux/kernel.h>
48#include <linux/skbuff.h>
49#include <linux/jiffies.h>
50
51
52#include <linux/fs.h>
53#include <linux/sysctl.h>
54
55#include <net/ip_vs.h>
56
57
58
59
60
61
62#define CHECK_EXPIRE_INTERVAL (60*HZ)
63#define ENTRY_TIMEOUT (6*60*HZ)
64
65
66
67
68
69
70
71#define COUNT_FOR_FULL_EXPIRATION 30
72static int sysctl_ip_vs_lblc_expiration = 24*60*60*HZ;
73
74
75
76
77
78#ifndef CONFIG_IP_VS_LBLC_TAB_BITS
79#define CONFIG_IP_VS_LBLC_TAB_BITS 10
80#endif
81#define IP_VS_LBLC_TAB_BITS CONFIG_IP_VS_LBLC_TAB_BITS
82#define IP_VS_LBLC_TAB_SIZE (1 << IP_VS_LBLC_TAB_BITS)
83#define IP_VS_LBLC_TAB_MASK (IP_VS_LBLC_TAB_SIZE - 1)
84
85
86
87
88
89
90struct ip_vs_lblc_entry {
91 struct list_head list;
92 int af;
93 union nf_inet_addr addr;
94 struct ip_vs_dest *dest;
95 unsigned long lastuse;
96};
97
98
99
100
101
102struct ip_vs_lblc_table {
103 struct list_head bucket[IP_VS_LBLC_TAB_SIZE];
104 atomic_t entries;
105 int max_size;
106 struct timer_list periodic_timer;
107 int rover;
108 int counter;
109};
110
111
112
113
114
115
116static ctl_table vs_vars_table[] = {
117 {
118 .procname = "lblc_expiration",
119 .data = &sysctl_ip_vs_lblc_expiration,
120 .maxlen = sizeof(int),
121 .mode = 0644,
122 .proc_handler = proc_dointvec_jiffies,
123 },
124 { .ctl_name = 0 }
125};
126
127static struct ctl_table_header * sysctl_header;
128
129static inline void ip_vs_lblc_free(struct ip_vs_lblc_entry *en)
130{
131 list_del(&en->list);
132
133
134
135
136 atomic_dec(&en->dest->refcnt);
137 kfree(en);
138}
139
140
141
142
143
144static inline unsigned
145ip_vs_lblc_hashkey(int af, const union nf_inet_addr *addr)
146{
147 __be32 addr_fold = addr->ip;
148
149#ifdef CONFIG_IP_VS_IPV6
150 if (af == AF_INET6)
151 addr_fold = addr->ip6[0]^addr->ip6[1]^
152 addr->ip6[2]^addr->ip6[3];
153#endif
154 return (ntohl(addr_fold)*2654435761UL) & IP_VS_LBLC_TAB_MASK;
155}
156
157
158
159
160
161
162static void
163ip_vs_lblc_hash(struct ip_vs_lblc_table *tbl, struct ip_vs_lblc_entry *en)
164{
165 unsigned hash = ip_vs_lblc_hashkey(en->af, &en->addr);
166
167 list_add(&en->list, &tbl->bucket[hash]);
168 atomic_inc(&tbl->entries);
169}
170
171
172
173
174
175
176static inline struct ip_vs_lblc_entry *
177ip_vs_lblc_get(int af, struct ip_vs_lblc_table *tbl,
178 const union nf_inet_addr *addr)
179{
180 unsigned hash = ip_vs_lblc_hashkey(af, addr);
181 struct ip_vs_lblc_entry *en;
182
183 list_for_each_entry(en, &tbl->bucket[hash], list)
184 if (ip_vs_addr_equal(af, &en->addr, addr))
185 return en;
186
187 return NULL;
188}
189
190
191
192
193
194
195static inline struct ip_vs_lblc_entry *
196ip_vs_lblc_new(struct ip_vs_lblc_table *tbl, const union nf_inet_addr *daddr,
197 struct ip_vs_dest *dest)
198{
199 struct ip_vs_lblc_entry *en;
200
201 en = ip_vs_lblc_get(dest->af, tbl, daddr);
202 if (!en) {
203 en = kmalloc(sizeof(*en), GFP_ATOMIC);
204 if (!en) {
205 pr_err("%s(): no memory\n", __func__);
206 return NULL;
207 }
208
209 en->af = dest->af;
210 ip_vs_addr_copy(dest->af, &en->addr, daddr);
211 en->lastuse = jiffies;
212
213 atomic_inc(&dest->refcnt);
214 en->dest = dest;
215
216 ip_vs_lblc_hash(tbl, en);
217 } else if (en->dest != dest) {
218 atomic_dec(&en->dest->refcnt);
219 atomic_inc(&dest->refcnt);
220 en->dest = dest;
221 }
222
223 return en;
224}
225
226
227
228
229
230static void ip_vs_lblc_flush(struct ip_vs_lblc_table *tbl)
231{
232 struct ip_vs_lblc_entry *en, *nxt;
233 int i;
234
235 for (i=0; i<IP_VS_LBLC_TAB_SIZE; i++) {
236 list_for_each_entry_safe(en, nxt, &tbl->bucket[i], list) {
237 ip_vs_lblc_free(en);
238 atomic_dec(&tbl->entries);
239 }
240 }
241}
242
243
244static inline void ip_vs_lblc_full_check(struct ip_vs_service *svc)
245{
246 struct ip_vs_lblc_table *tbl = svc->sched_data;
247 struct ip_vs_lblc_entry *en, *nxt;
248 unsigned long now = jiffies;
249 int i, j;
250
251 for (i=0, j=tbl->rover; i<IP_VS_LBLC_TAB_SIZE; i++) {
252 j = (j + 1) & IP_VS_LBLC_TAB_MASK;
253
254 write_lock(&svc->sched_lock);
255 list_for_each_entry_safe(en, nxt, &tbl->bucket[j], list) {
256 if (time_before(now,
257 en->lastuse + sysctl_ip_vs_lblc_expiration))
258 continue;
259
260 ip_vs_lblc_free(en);
261 atomic_dec(&tbl->entries);
262 }
263 write_unlock(&svc->sched_lock);
264 }
265 tbl->rover = j;
266}
267
268
269
270
271
272
273
274
275
276
277
278
279
280static void ip_vs_lblc_check_expire(unsigned long data)
281{
282 struct ip_vs_service *svc = (struct ip_vs_service *) data;
283 struct ip_vs_lblc_table *tbl = svc->sched_data;
284 unsigned long now = jiffies;
285 int goal;
286 int i, j;
287 struct ip_vs_lblc_entry *en, *nxt;
288
289 if ((tbl->counter % COUNT_FOR_FULL_EXPIRATION) == 0) {
290
291 ip_vs_lblc_full_check(svc);
292 tbl->counter = 1;
293 goto out;
294 }
295
296 if (atomic_read(&tbl->entries) <= tbl->max_size) {
297 tbl->counter++;
298 goto out;
299 }
300
301 goal = (atomic_read(&tbl->entries) - tbl->max_size)*4/3;
302 if (goal > tbl->max_size/2)
303 goal = tbl->max_size/2;
304
305 for (i=0, j=tbl->rover; i<IP_VS_LBLC_TAB_SIZE; i++) {
306 j = (j + 1) & IP_VS_LBLC_TAB_MASK;
307
308 write_lock(&svc->sched_lock);
309 list_for_each_entry_safe(en, nxt, &tbl->bucket[j], list) {
310 if (time_before(now, en->lastuse + ENTRY_TIMEOUT))
311 continue;
312
313 ip_vs_lblc_free(en);
314 atomic_dec(&tbl->entries);
315 goal--;
316 }
317 write_unlock(&svc->sched_lock);
318 if (goal <= 0)
319 break;
320 }
321 tbl->rover = j;
322
323 out:
324 mod_timer(&tbl->periodic_timer, jiffies+CHECK_EXPIRE_INTERVAL);
325}
326
327
328static int ip_vs_lblc_init_svc(struct ip_vs_service *svc)
329{
330 int i;
331 struct ip_vs_lblc_table *tbl;
332
333
334
335
336 tbl = kmalloc(sizeof(*tbl), GFP_ATOMIC);
337 if (tbl == NULL) {
338 pr_err("%s(): no memory\n", __func__);
339 return -ENOMEM;
340 }
341 svc->sched_data = tbl;
342 IP_VS_DBG(6, "LBLC hash table (memory=%Zdbytes) allocated for "
343 "current service\n", sizeof(*tbl));
344
345
346
347
348 for (i=0; i<IP_VS_LBLC_TAB_SIZE; i++) {
349 INIT_LIST_HEAD(&tbl->bucket[i]);
350 }
351 tbl->max_size = IP_VS_LBLC_TAB_SIZE*16;
352 tbl->rover = 0;
353 tbl->counter = 1;
354
355
356
357
358 setup_timer(&tbl->periodic_timer, ip_vs_lblc_check_expire,
359 (unsigned long)svc);
360 mod_timer(&tbl->periodic_timer, jiffies + CHECK_EXPIRE_INTERVAL);
361
362 return 0;
363}
364
365
366static int ip_vs_lblc_done_svc(struct ip_vs_service *svc)
367{
368 struct ip_vs_lblc_table *tbl = svc->sched_data;
369
370
371 del_timer_sync(&tbl->periodic_timer);
372
373
374 ip_vs_lblc_flush(tbl);
375
376
377 kfree(tbl);
378 IP_VS_DBG(6, "LBLC hash table (memory=%Zdbytes) released\n",
379 sizeof(*tbl));
380
381 return 0;
382}
383
384
385static inline struct ip_vs_dest *
386__ip_vs_lblc_schedule(struct ip_vs_service *svc)
387{
388 struct ip_vs_dest *dest, *least;
389 int loh, doh;
390
391
392
393
394
395
396
397
398
399
400
401
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403
404
405
406
407
408 list_for_each_entry(dest, &svc->destinations, n_list) {
409 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
410 continue;
411 if (atomic_read(&dest->weight) > 0) {
412 least = dest;
413 loh = atomic_read(&least->activeconns) * 50
414 + atomic_read(&least->inactconns);
415 goto nextstage;
416 }
417 }
418 return NULL;
419
420
421
422
423 nextstage:
424 list_for_each_entry_continue(dest, &svc->destinations, n_list) {
425 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
426 continue;
427
428 doh = atomic_read(&dest->activeconns) * 50
429 + atomic_read(&dest->inactconns);
430 if (loh * atomic_read(&dest->weight) >
431 doh * atomic_read(&least->weight)) {
432 least = dest;
433 loh = doh;
434 }
435 }
436
437 IP_VS_DBG_BUF(6, "LBLC: server %s:%d "
438 "activeconns %d refcnt %d weight %d overhead %d\n",
439 IP_VS_DBG_ADDR(least->af, &least->addr),
440 ntohs(least->port),
441 atomic_read(&least->activeconns),
442 atomic_read(&least->refcnt),
443 atomic_read(&least->weight), loh);
444
445 return least;
446}
447
448
449
450
451
452
453static inline int
454is_overloaded(struct ip_vs_dest *dest, struct ip_vs_service *svc)
455{
456 if (atomic_read(&dest->activeconns) > atomic_read(&dest->weight)) {
457 struct ip_vs_dest *d;
458
459 list_for_each_entry(d, &svc->destinations, n_list) {
460 if (atomic_read(&d->activeconns)*2
461 < atomic_read(&d->weight)) {
462 return 1;
463 }
464 }
465 }
466 return 0;
467}
468
469
470
471
472
473static struct ip_vs_dest *
474ip_vs_lblc_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
475{
476 struct ip_vs_lblc_table *tbl = svc->sched_data;
477 struct ip_vs_iphdr iph;
478 struct ip_vs_dest *dest = NULL;
479 struct ip_vs_lblc_entry *en;
480
481 ip_vs_fill_iphdr(svc->af, skb_network_header(skb), &iph);
482
483 IP_VS_DBG(6, "%s(): Scheduling...\n", __func__);
484
485
486 read_lock(&svc->sched_lock);
487 en = ip_vs_lblc_get(svc->af, tbl, &iph.daddr);
488 if (en) {
489
490 en->lastuse = jiffies;
491
492
493
494
495
496
497
498
499
500
501 if (en->dest->flags & IP_VS_DEST_F_AVAILABLE)
502 dest = en->dest;
503 }
504 read_unlock(&svc->sched_lock);
505
506
507 if (dest && atomic_read(&dest->weight) > 0 && !is_overloaded(dest, svc))
508 goto out;
509
510
511 dest = __ip_vs_lblc_schedule(svc);
512 if (!dest) {
513 IP_VS_ERR_RL("LBLC: no destination available\n");
514 return NULL;
515 }
516
517
518 write_lock(&svc->sched_lock);
519 ip_vs_lblc_new(tbl, &iph.daddr, dest);
520 write_unlock(&svc->sched_lock);
521
522out:
523 IP_VS_DBG_BUF(6, "LBLC: destination IP address %s --> server %s:%d\n",
524 IP_VS_DBG_ADDR(svc->af, &iph.daddr),
525 IP_VS_DBG_ADDR(svc->af, &dest->addr), ntohs(dest->port));
526
527 return dest;
528}
529
530
531
532
533
534static struct ip_vs_scheduler ip_vs_lblc_scheduler =
535{
536 .name = "lblc",
537 .refcnt = ATOMIC_INIT(0),
538 .module = THIS_MODULE,
539 .n_list = LIST_HEAD_INIT(ip_vs_lblc_scheduler.n_list),
540 .init_service = ip_vs_lblc_init_svc,
541 .done_service = ip_vs_lblc_done_svc,
542 .schedule = ip_vs_lblc_schedule,
543};
544
545
546static int __init ip_vs_lblc_init(void)
547{
548 int ret;
549
550 sysctl_header = register_sysctl_paths(net_vs_ctl_path, vs_vars_table);
551 ret = register_ip_vs_scheduler(&ip_vs_lblc_scheduler);
552 if (ret)
553 unregister_sysctl_table(sysctl_header);
554 return ret;
555}
556
557
558static void __exit ip_vs_lblc_cleanup(void)
559{
560 unregister_sysctl_table(sysctl_header);
561 unregister_ip_vs_scheduler(&ip_vs_lblc_scheduler);
562}
563
564
565module_init(ip_vs_lblc_init);
566module_exit(ip_vs_lblc_cleanup);
567MODULE_LICENSE("GPL");
568