[NET]: Convert init_timer into setup_timer
[linux-2.6.git] / net / ipv4 / ipvs / ip_vs_lblcr.c
1 /*
2  * IPVS:        Locality-Based Least-Connection with Replication scheduler
3  *
4  * Version:     $Id: ip_vs_lblcr.c,v 1.11 2002/09/15 08:14:08 wensong Exp $
5  *
6  * Authors:     Wensong Zhang <wensong@gnuchina.org>
7  *
8  *              This program is free software; you can redistribute it and/or
9  *              modify it under the terms of the GNU General Public License
10  *              as published by the Free Software Foundation; either version
11  *              2 of the License, or (at your option) any later version.
12  *
13  * Changes:
14  *     Julian Anastasov        :    Added the missing (dest->weight>0)
15  *                                  condition in the ip_vs_dest_set_max.
16  *
17  */
18
19 /*
20  * The lblc/r algorithm is as follows (pseudo code):
21  *
22  *       if serverSet[dest_ip] is null then
23  *               n, serverSet[dest_ip] <- {weighted least-conn node};
24  *       else
25  *               n <- {least-conn (alive) node in serverSet[dest_ip]};
26  *               if (n is null) OR
27  *                  (n.conns>n.weight AND
28  *                   there is a node m with m.conns<m.weight/2) then
29  *                   n <- {weighted least-conn node};
30  *                   add n to serverSet[dest_ip];
31  *               if |serverSet[dest_ip]| > 1 AND
32  *                   now - serverSet[dest_ip].lastMod > T then
33  *                   m <- {most conn node in serverSet[dest_ip]};
34  *                   remove m from serverSet[dest_ip];
35  *       if serverSet[dest_ip] changed then
36  *               serverSet[dest_ip].lastMod <- now;
37  *
38  *       return n;
39  *
40  */
41
42 #include <linux/ip.h>
43 #include <linux/module.h>
44 #include <linux/kernel.h>
45 #include <linux/skbuff.h>
46 #include <linux/jiffies.h>
47
48 /* for sysctl */
49 #include <linux/fs.h>
50 #include <linux/sysctl.h>
51 #include <net/net_namespace.h>
52
53 #include <net/ip_vs.h>
54
55
56 /*
57  *    It is for garbage collection of stale IPVS lblcr entries,
58  *    when the table is full.
59  */
60 #define CHECK_EXPIRE_INTERVAL   (60*HZ)
61 #define ENTRY_TIMEOUT           (6*60*HZ)
62
63 /*
64  *    It is for full expiration check.
65  *    When there is no partial expiration check (garbage collection)
66  *    in a half hour, do a full expiration check to collect stale
67  *    entries that haven't been touched for a day.
68  */
69 #define COUNT_FOR_FULL_EXPIRATION   30
70 static int sysctl_ip_vs_lblcr_expiration = 24*60*60*HZ;
71
72
73 /*
74  *     for IPVS lblcr entry hash table
75  */
76 #ifndef CONFIG_IP_VS_LBLCR_TAB_BITS
77 #define CONFIG_IP_VS_LBLCR_TAB_BITS      10
78 #endif
79 #define IP_VS_LBLCR_TAB_BITS     CONFIG_IP_VS_LBLCR_TAB_BITS
80 #define IP_VS_LBLCR_TAB_SIZE     (1 << IP_VS_LBLCR_TAB_BITS)
81 #define IP_VS_LBLCR_TAB_MASK     (IP_VS_LBLCR_TAB_SIZE - 1)
82
83
84 /*
85  *      IPVS destination set structure and operations
86  */
87 struct ip_vs_dest_list {
88         struct ip_vs_dest_list  *next;          /* list link */
89         struct ip_vs_dest       *dest;          /* destination server */
90 };
91
92 struct ip_vs_dest_set {
93         atomic_t                size;           /* set size */
94         unsigned long           lastmod;        /* last modified time */
95         struct ip_vs_dest_list  *list;          /* destination list */
96         rwlock_t                lock;           /* lock for this list */
97 };
98
99
100 static struct ip_vs_dest_list *
101 ip_vs_dest_set_insert(struct ip_vs_dest_set *set, struct ip_vs_dest *dest)
102 {
103         struct ip_vs_dest_list *e;
104
105         for (e=set->list; e!=NULL; e=e->next) {
106                 if (e->dest == dest)
107                         /* already existed */
108                         return NULL;
109         }
110
111         e = kmalloc(sizeof(struct ip_vs_dest_list), GFP_ATOMIC);
112         if (e == NULL) {
113                 IP_VS_ERR("ip_vs_dest_set_insert(): no memory\n");
114                 return NULL;
115         }
116
117         atomic_inc(&dest->refcnt);
118         e->dest = dest;
119
120         /* link it to the list */
121         write_lock(&set->lock);
122         e->next = set->list;
123         set->list = e;
124         atomic_inc(&set->size);
125         write_unlock(&set->lock);
126
127         set->lastmod = jiffies;
128         return e;
129 }
130
131 static void
132 ip_vs_dest_set_erase(struct ip_vs_dest_set *set, struct ip_vs_dest *dest)
133 {
134         struct ip_vs_dest_list *e, **ep;
135
136         write_lock(&set->lock);
137         for (ep=&set->list, e=*ep; e!=NULL; e=*ep) {
138                 if (e->dest == dest) {
139                         /* HIT */
140                         *ep = e->next;
141                         atomic_dec(&set->size);
142                         set->lastmod = jiffies;
143                         atomic_dec(&e->dest->refcnt);
144                         kfree(e);
145                         break;
146                 }
147                 ep = &e->next;
148         }
149         write_unlock(&set->lock);
150 }
151
152 static void ip_vs_dest_set_eraseall(struct ip_vs_dest_set *set)
153 {
154         struct ip_vs_dest_list *e, **ep;
155
156         write_lock(&set->lock);
157         for (ep=&set->list, e=*ep; e!=NULL; e=*ep) {
158                 *ep = e->next;
159                 /*
160                  * We don't kfree dest because it is refered either
161                  * by its service or by the trash dest list.
162                  */
163                 atomic_dec(&e->dest->refcnt);
164                 kfree(e);
165         }
166         write_unlock(&set->lock);
167 }
168
169 /* get weighted least-connection node in the destination set */
170 static inline struct ip_vs_dest *ip_vs_dest_set_min(struct ip_vs_dest_set *set)
171 {
172         register struct ip_vs_dest_list *e;
173         struct ip_vs_dest *dest, *least;
174         int loh, doh;
175
176         if (set == NULL)
177                 return NULL;
178
179         read_lock(&set->lock);
180         /* select the first destination server, whose weight > 0 */
181         for (e=set->list; e!=NULL; e=e->next) {
182                 least = e->dest;
183                 if (least->flags & IP_VS_DEST_F_OVERLOAD)
184                         continue;
185
186                 if ((atomic_read(&least->weight) > 0)
187                     && (least->flags & IP_VS_DEST_F_AVAILABLE)) {
188                         loh = atomic_read(&least->activeconns) * 50
189                                 + atomic_read(&least->inactconns);
190                         goto nextstage;
191                 }
192         }
193         read_unlock(&set->lock);
194         return NULL;
195
196         /* find the destination with the weighted least load */
197   nextstage:
198         for (e=e->next; e!=NULL; e=e->next) {
199                 dest = e->dest;
200                 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
201                         continue;
202
203                 doh = atomic_read(&dest->activeconns) * 50
204                         + atomic_read(&dest->inactconns);
205                 if ((loh * atomic_read(&dest->weight) >
206                      doh * atomic_read(&least->weight))
207                     && (dest->flags & IP_VS_DEST_F_AVAILABLE)) {
208                         least = dest;
209                         loh = doh;
210                 }
211         }
212         read_unlock(&set->lock);
213
214         IP_VS_DBG(6, "ip_vs_dest_set_min: server %d.%d.%d.%d:%d "
215                   "activeconns %d refcnt %d weight %d overhead %d\n",
216                   NIPQUAD(least->addr), ntohs(least->port),
217                   atomic_read(&least->activeconns),
218                   atomic_read(&least->refcnt),
219                   atomic_read(&least->weight), loh);
220         return least;
221 }
222
223
224 /* get weighted most-connection node in the destination set */
225 static inline struct ip_vs_dest *ip_vs_dest_set_max(struct ip_vs_dest_set *set)
226 {
227         register struct ip_vs_dest_list *e;
228         struct ip_vs_dest *dest, *most;
229         int moh, doh;
230
231         if (set == NULL)
232                 return NULL;
233
234         read_lock(&set->lock);
235         /* select the first destination server, whose weight > 0 */
236         for (e=set->list; e!=NULL; e=e->next) {
237                 most = e->dest;
238                 if (atomic_read(&most->weight) > 0) {
239                         moh = atomic_read(&most->activeconns) * 50
240                                 + atomic_read(&most->inactconns);
241                         goto nextstage;
242                 }
243         }
244         read_unlock(&set->lock);
245         return NULL;
246
247         /* find the destination with the weighted most load */
248   nextstage:
249         for (e=e->next; e!=NULL; e=e->next) {
250                 dest = e->dest;
251                 doh = atomic_read(&dest->activeconns) * 50
252                         + atomic_read(&dest->inactconns);
253                 /* moh/mw < doh/dw ==> moh*dw < doh*mw, where mw,dw>0 */
254                 if ((moh * atomic_read(&dest->weight) <
255                      doh * atomic_read(&most->weight))
256                     && (atomic_read(&dest->weight) > 0)) {
257                         most = dest;
258                         moh = doh;
259                 }
260         }
261         read_unlock(&set->lock);
262
263         IP_VS_DBG(6, "ip_vs_dest_set_max: server %d.%d.%d.%d:%d "
264                   "activeconns %d refcnt %d weight %d overhead %d\n",
265                   NIPQUAD(most->addr), ntohs(most->port),
266                   atomic_read(&most->activeconns),
267                   atomic_read(&most->refcnt),
268                   atomic_read(&most->weight), moh);
269         return most;
270 }
271
272
273 /*
274  *      IPVS lblcr entry represents an association between destination
275  *      IP address and its destination server set
276  */
277 struct ip_vs_lblcr_entry {
278         struct list_head        list;
279         __be32                   addr;           /* destination IP address */
280         struct ip_vs_dest_set   set;            /* destination server set */
281         unsigned long           lastuse;        /* last used time */
282 };
283
284
285 /*
286  *      IPVS lblcr hash table
287  */
288 struct ip_vs_lblcr_table {
289         rwlock_t                lock;           /* lock for this table */
290         struct list_head        bucket[IP_VS_LBLCR_TAB_SIZE];  /* hash bucket */
291         atomic_t                entries;        /* number of entries */
292         int                     max_size;       /* maximum size of entries */
293         struct timer_list       periodic_timer; /* collect stale entries */
294         int                     rover;          /* rover for expire check */
295         int                     counter;        /* counter for no expire */
296 };
297
298
299 /*
300  *      IPVS LBLCR sysctl table
301  */
302
303 static ctl_table vs_vars_table[] = {
304         {
305                 .procname       = "lblcr_expiration",
306                 .data           = &sysctl_ip_vs_lblcr_expiration,
307                 .maxlen         = sizeof(int),
308                 .mode           = 0644,
309                 .proc_handler   = &proc_dointvec_jiffies,
310         },
311         { .ctl_name = 0 }
312 };
313
314 static ctl_table vs_table[] = {
315         {
316                 .procname       = "vs",
317                 .mode           = 0555,
318                 .child          = vs_vars_table
319         },
320         { .ctl_name = 0 }
321 };
322
323 static ctl_table ipvs_ipv4_table[] = {
324         {
325                 .ctl_name       = NET_IPV4,
326                 .procname       = "ipv4",
327                 .mode           = 0555,
328                 .child          = vs_table
329         },
330         { .ctl_name = 0 }
331 };
332
333 static ctl_table lblcr_root_table[] = {
334         {
335                 .ctl_name       = CTL_NET,
336                 .procname       = "net",
337                 .mode           = 0555,
338                 .child          = ipvs_ipv4_table
339         },
340         { .ctl_name = 0 }
341 };
342
343 static struct ctl_table_header * sysctl_header;
344
345 /*
346  *      new/free a ip_vs_lblcr_entry, which is a mapping of a destination
347  *      IP address to a server.
348  */
349 static inline struct ip_vs_lblcr_entry *ip_vs_lblcr_new(__be32 daddr)
350 {
351         struct ip_vs_lblcr_entry *en;
352
353         en = kmalloc(sizeof(struct ip_vs_lblcr_entry), GFP_ATOMIC);
354         if (en == NULL) {
355                 IP_VS_ERR("ip_vs_lblcr_new(): no memory\n");
356                 return NULL;
357         }
358
359         INIT_LIST_HEAD(&en->list);
360         en->addr = daddr;
361
362         /* initilize its dest set */
363         atomic_set(&(en->set.size), 0);
364         en->set.list = NULL;
365         rwlock_init(&en->set.lock);
366
367         return en;
368 }
369
370
371 static inline void ip_vs_lblcr_free(struct ip_vs_lblcr_entry *en)
372 {
373         list_del(&en->list);
374         ip_vs_dest_set_eraseall(&en->set);
375         kfree(en);
376 }
377
378
379 /*
380  *      Returns hash value for IPVS LBLCR entry
381  */
382 static inline unsigned ip_vs_lblcr_hashkey(__be32 addr)
383 {
384         return (ntohl(addr)*2654435761UL) & IP_VS_LBLCR_TAB_MASK;
385 }
386
387
388 /*
389  *      Hash an entry in the ip_vs_lblcr_table.
390  *      returns bool success.
391  */
392 static int
393 ip_vs_lblcr_hash(struct ip_vs_lblcr_table *tbl, struct ip_vs_lblcr_entry *en)
394 {
395         unsigned hash;
396
397         if (!list_empty(&en->list)) {
398                 IP_VS_ERR("ip_vs_lblcr_hash(): request for already hashed, "
399                           "called from %p\n", __builtin_return_address(0));
400                 return 0;
401         }
402
403         /*
404          *      Hash by destination IP address
405          */
406         hash = ip_vs_lblcr_hashkey(en->addr);
407
408         write_lock(&tbl->lock);
409         list_add(&en->list, &tbl->bucket[hash]);
410         atomic_inc(&tbl->entries);
411         write_unlock(&tbl->lock);
412
413         return 1;
414 }
415
416
417 /*
418  *  Get ip_vs_lblcr_entry associated with supplied parameters.
419  */
420 static inline struct ip_vs_lblcr_entry *
421 ip_vs_lblcr_get(struct ip_vs_lblcr_table *tbl, __be32 addr)
422 {
423         unsigned hash;
424         struct ip_vs_lblcr_entry *en;
425
426         hash = ip_vs_lblcr_hashkey(addr);
427
428         read_lock(&tbl->lock);
429
430         list_for_each_entry(en, &tbl->bucket[hash], list) {
431                 if (en->addr == addr) {
432                         /* HIT */
433                         read_unlock(&tbl->lock);
434                         return en;
435                 }
436         }
437
438         read_unlock(&tbl->lock);
439
440         return NULL;
441 }
442
443
444 /*
445  *      Flush all the entries of the specified table.
446  */
447 static void ip_vs_lblcr_flush(struct ip_vs_lblcr_table *tbl)
448 {
449         int i;
450         struct ip_vs_lblcr_entry *en, *nxt;
451
452         for (i=0; i<IP_VS_LBLCR_TAB_SIZE; i++) {
453                 write_lock(&tbl->lock);
454                 list_for_each_entry_safe(en, nxt, &tbl->bucket[i], list) {
455                         ip_vs_lblcr_free(en);
456                         atomic_dec(&tbl->entries);
457                 }
458                 write_unlock(&tbl->lock);
459         }
460 }
461
462
463 static inline void ip_vs_lblcr_full_check(struct ip_vs_lblcr_table *tbl)
464 {
465         unsigned long now = jiffies;
466         int i, j;
467         struct ip_vs_lblcr_entry *en, *nxt;
468
469         for (i=0, j=tbl->rover; i<IP_VS_LBLCR_TAB_SIZE; i++) {
470                 j = (j + 1) & IP_VS_LBLCR_TAB_MASK;
471
472                 write_lock(&tbl->lock);
473                 list_for_each_entry_safe(en, nxt, &tbl->bucket[j], list) {
474                         if (time_after(en->lastuse+sysctl_ip_vs_lblcr_expiration,
475                                        now))
476                                 continue;
477
478                         ip_vs_lblcr_free(en);
479                         atomic_dec(&tbl->entries);
480                 }
481                 write_unlock(&tbl->lock);
482         }
483         tbl->rover = j;
484 }
485
486
487 /*
488  *      Periodical timer handler for IPVS lblcr table
489  *      It is used to collect stale entries when the number of entries
490  *      exceeds the maximum size of the table.
491  *
492  *      Fixme: we probably need more complicated algorithm to collect
493  *             entries that have not been used for a long time even
494  *             if the number of entries doesn't exceed the maximum size
495  *             of the table.
496  *      The full expiration check is for this purpose now.
497  */
498 static void ip_vs_lblcr_check_expire(unsigned long data)
499 {
500         struct ip_vs_lblcr_table *tbl;
501         unsigned long now = jiffies;
502         int goal;
503         int i, j;
504         struct ip_vs_lblcr_entry *en, *nxt;
505
506         tbl = (struct ip_vs_lblcr_table *)data;
507
508         if ((tbl->counter % COUNT_FOR_FULL_EXPIRATION) == 0) {
509                 /* do full expiration check */
510                 ip_vs_lblcr_full_check(tbl);
511                 tbl->counter = 1;
512                 goto out;
513         }
514
515         if (atomic_read(&tbl->entries) <= tbl->max_size) {
516                 tbl->counter++;
517                 goto out;
518         }
519
520         goal = (atomic_read(&tbl->entries) - tbl->max_size)*4/3;
521         if (goal > tbl->max_size/2)
522                 goal = tbl->max_size/2;
523
524         for (i=0, j=tbl->rover; i<IP_VS_LBLCR_TAB_SIZE; i++) {
525                 j = (j + 1) & IP_VS_LBLCR_TAB_MASK;
526
527                 write_lock(&tbl->lock);
528                 list_for_each_entry_safe(en, nxt, &tbl->bucket[j], list) {
529                         if (time_before(now, en->lastuse+ENTRY_TIMEOUT))
530                                 continue;
531
532                         ip_vs_lblcr_free(en);
533                         atomic_dec(&tbl->entries);
534                         goal--;
535                 }
536                 write_unlock(&tbl->lock);
537                 if (goal <= 0)
538                         break;
539         }
540         tbl->rover = j;
541
542   out:
543         mod_timer(&tbl->periodic_timer, jiffies+CHECK_EXPIRE_INTERVAL);
544 }
545
546 static int ip_vs_lblcr_init_svc(struct ip_vs_service *svc)
547 {
548         int i;
549         struct ip_vs_lblcr_table *tbl;
550
551         /*
552          *    Allocate the ip_vs_lblcr_table for this service
553          */
554         tbl = kmalloc(sizeof(struct ip_vs_lblcr_table), GFP_ATOMIC);
555         if (tbl == NULL) {
556                 IP_VS_ERR("ip_vs_lblcr_init_svc(): no memory\n");
557                 return -ENOMEM;
558         }
559         svc->sched_data = tbl;
560         IP_VS_DBG(6, "LBLCR hash table (memory=%Zdbytes) allocated for "
561                   "current service\n",
562                   sizeof(struct ip_vs_lblcr_table));
563
564         /*
565          *    Initialize the hash buckets
566          */
567         for (i=0; i<IP_VS_LBLCR_TAB_SIZE; i++) {
568                 INIT_LIST_HEAD(&tbl->bucket[i]);
569         }
570         rwlock_init(&tbl->lock);
571         tbl->max_size = IP_VS_LBLCR_TAB_SIZE*16;
572         tbl->rover = 0;
573         tbl->counter = 1;
574
575         /*
576          *    Hook periodic timer for garbage collection
577          */
578         setup_timer(&tbl->periodic_timer, ip_vs_lblcr_check_expire,
579                         (unsigned long)tbl);
580         tbl->periodic_timer.expires = jiffies+CHECK_EXPIRE_INTERVAL;
581         add_timer(&tbl->periodic_timer);
582
583         return 0;
584 }
585
586
587 static int ip_vs_lblcr_done_svc(struct ip_vs_service *svc)
588 {
589         struct ip_vs_lblcr_table *tbl = svc->sched_data;
590
591         /* remove periodic timer */
592         del_timer_sync(&tbl->periodic_timer);
593
594         /* got to clean up table entries here */
595         ip_vs_lblcr_flush(tbl);
596
597         /* release the table itself */
598         kfree(svc->sched_data);
599         IP_VS_DBG(6, "LBLCR hash table (memory=%Zdbytes) released\n",
600                   sizeof(struct ip_vs_lblcr_table));
601
602         return 0;
603 }
604
605
606 static int ip_vs_lblcr_update_svc(struct ip_vs_service *svc)
607 {
608         return 0;
609 }
610
611
612 static inline struct ip_vs_dest *
613 __ip_vs_wlc_schedule(struct ip_vs_service *svc, struct iphdr *iph)
614 {
615         struct ip_vs_dest *dest, *least;
616         int loh, doh;
617
618         /*
619          * We think the overhead of processing active connections is fifty
620          * times higher than that of inactive connections in average. (This
621          * fifty times might not be accurate, we will change it later.) We
622          * use the following formula to estimate the overhead:
623          *                dest->activeconns*50 + dest->inactconns
624          * and the load:
625          *                (dest overhead) / dest->weight
626          *
627          * Remember -- no floats in kernel mode!!!
628          * The comparison of h1*w2 > h2*w1 is equivalent to that of
629          *                h1/w1 > h2/w2
630          * if every weight is larger than zero.
631          *
632          * The server with weight=0 is quiesced and will not receive any
633          * new connection.
634          */
635         list_for_each_entry(dest, &svc->destinations, n_list) {
636                 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
637                         continue;
638
639                 if (atomic_read(&dest->weight) > 0) {
640                         least = dest;
641                         loh = atomic_read(&least->activeconns) * 50
642                                 + atomic_read(&least->inactconns);
643                         goto nextstage;
644                 }
645         }
646         return NULL;
647
648         /*
649          *    Find the destination with the least load.
650          */
651   nextstage:
652         list_for_each_entry_continue(dest, &svc->destinations, n_list) {
653                 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
654                         continue;
655
656                 doh = atomic_read(&dest->activeconns) * 50
657                         + atomic_read(&dest->inactconns);
658                 if (loh * atomic_read(&dest->weight) >
659                     doh * atomic_read(&least->weight)) {
660                         least = dest;
661                         loh = doh;
662                 }
663         }
664
665         IP_VS_DBG(6, "LBLCR: server %d.%d.%d.%d:%d "
666                   "activeconns %d refcnt %d weight %d overhead %d\n",
667                   NIPQUAD(least->addr), ntohs(least->port),
668                   atomic_read(&least->activeconns),
669                   atomic_read(&least->refcnt),
670                   atomic_read(&least->weight), loh);
671
672         return least;
673 }
674
675
676 /*
677  *   If this destination server is overloaded and there is a less loaded
678  *   server, then return true.
679  */
680 static inline int
681 is_overloaded(struct ip_vs_dest *dest, struct ip_vs_service *svc)
682 {
683         if (atomic_read(&dest->activeconns) > atomic_read(&dest->weight)) {
684                 struct ip_vs_dest *d;
685
686                 list_for_each_entry(d, &svc->destinations, n_list) {
687                         if (atomic_read(&d->activeconns)*2
688                             < atomic_read(&d->weight)) {
689                                 return 1;
690                         }
691                 }
692         }
693         return 0;
694 }
695
696
697 /*
698  *    Locality-Based (weighted) Least-Connection scheduling
699  */
700 static struct ip_vs_dest *
701 ip_vs_lblcr_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
702 {
703         struct ip_vs_dest *dest;
704         struct ip_vs_lblcr_table *tbl;
705         struct ip_vs_lblcr_entry *en;
706         struct iphdr *iph = ip_hdr(skb);
707
708         IP_VS_DBG(6, "ip_vs_lblcr_schedule(): Scheduling...\n");
709
710         tbl = (struct ip_vs_lblcr_table *)svc->sched_data;
711         en = ip_vs_lblcr_get(tbl, iph->daddr);
712         if (en == NULL) {
713                 dest = __ip_vs_wlc_schedule(svc, iph);
714                 if (dest == NULL) {
715                         IP_VS_DBG(1, "no destination available\n");
716                         return NULL;
717                 }
718                 en = ip_vs_lblcr_new(iph->daddr);
719                 if (en == NULL) {
720                         return NULL;
721                 }
722                 ip_vs_dest_set_insert(&en->set, dest);
723                 ip_vs_lblcr_hash(tbl, en);
724         } else {
725                 dest = ip_vs_dest_set_min(&en->set);
726                 if (!dest || is_overloaded(dest, svc)) {
727                         dest = __ip_vs_wlc_schedule(svc, iph);
728                         if (dest == NULL) {
729                                 IP_VS_DBG(1, "no destination available\n");
730                                 return NULL;
731                         }
732                         ip_vs_dest_set_insert(&en->set, dest);
733                 }
734                 if (atomic_read(&en->set.size) > 1 &&
735                     jiffies-en->set.lastmod > sysctl_ip_vs_lblcr_expiration) {
736                         struct ip_vs_dest *m;
737                         m = ip_vs_dest_set_max(&en->set);
738                         if (m)
739                                 ip_vs_dest_set_erase(&en->set, m);
740                 }
741         }
742         en->lastuse = jiffies;
743
744         IP_VS_DBG(6, "LBLCR: destination IP address %u.%u.%u.%u "
745                   "--> server %u.%u.%u.%u:%d\n",
746                   NIPQUAD(en->addr),
747                   NIPQUAD(dest->addr),
748                   ntohs(dest->port));
749
750         return dest;
751 }
752
753
754 /*
755  *      IPVS LBLCR Scheduler structure
756  */
757 static struct ip_vs_scheduler ip_vs_lblcr_scheduler =
758 {
759         .name =                 "lblcr",
760         .refcnt =               ATOMIC_INIT(0),
761         .module =               THIS_MODULE,
762         .init_service =         ip_vs_lblcr_init_svc,
763         .done_service =         ip_vs_lblcr_done_svc,
764         .update_service =       ip_vs_lblcr_update_svc,
765         .schedule =             ip_vs_lblcr_schedule,
766 };
767
768
769 static int __init ip_vs_lblcr_init(void)
770 {
771         int ret;
772
773         INIT_LIST_HEAD(&ip_vs_lblcr_scheduler.n_list);
774         sysctl_header = register_sysctl_table(lblcr_root_table);
775         ret = register_ip_vs_scheduler(&ip_vs_lblcr_scheduler);
776         if (ret)
777                 unregister_sysctl_table(sysctl_header);
778         return ret;
779 }
780
781
782 static void __exit ip_vs_lblcr_cleanup(void)
783 {
784         unregister_sysctl_table(sysctl_header);
785         unregister_ip_vs_scheduler(&ip_vs_lblcr_scheduler);
786 }
787
788
789 module_init(ip_vs_lblcr_init);
790 module_exit(ip_vs_lblcr_cleanup);
791 MODULE_LICENSE("GPL");