Merge /spare/repo/linux-2.6/
[linux-2.6] / net / ipv4 / ipvs / ip_vs_conn.c
1 /*
2  * IPVS         An implementation of the IP virtual server support for the
3  *              LINUX operating system.  IPVS is now implemented as a module
4  *              over the Netfilter framework. IPVS can be used to build a
5  *              high-performance and highly available server based on a
6  *              cluster of servers.
7  *
8  * Version:     $Id: ip_vs_conn.c,v 1.31 2003/04/18 09:03:16 wensong Exp $
9  *
10  * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
11  *              Peter Kese <peter.kese@ijs.si>
12  *              Julian Anastasov <ja@ssi.bg>
13  *
14  *              This program is free software; you can redistribute it and/or
15  *              modify it under the terms of the GNU General Public License
16  *              as published by the Free Software Foundation; either version
17  *              2 of the License, or (at your option) any later version.
18  *
19  * The IPVS code for kernel 2.2 was done by Wensong Zhang and Peter Kese,
20  * with changes/fixes from Julian Anastasov, Lars Marowsky-Bree, Horms
21  * and others. Many code here is taken from IP MASQ code of kernel 2.2.
22  *
23  * Changes:
24  *
25  */
26
27 #include <linux/kernel.h>
28 #include <linux/vmalloc.h>
29 #include <linux/proc_fs.h>              /* for proc_net_* */
30 #include <linux/seq_file.h>
31 #include <linux/jhash.h>
32 #include <linux/random.h>
33
34 #include <net/ip_vs.h>
35
36
37 /*
38  *  Connection hash table: for input and output packets lookups of IPVS
39  */
40 static struct list_head *ip_vs_conn_tab;
41
42 /*  SLAB cache for IPVS connections */
43 static kmem_cache_t *ip_vs_conn_cachep;
44
45 /*  counter for current IPVS connections */
46 static atomic_t ip_vs_conn_count = ATOMIC_INIT(0);
47
48 /*  counter for no client port connections */
49 static atomic_t ip_vs_conn_no_cport_cnt = ATOMIC_INIT(0);
50
51 /* random value for IPVS connection hash */
52 static unsigned int ip_vs_conn_rnd;
53
54 /*
55  *  Fine locking granularity for big connection hash table
56  */
57 #define CT_LOCKARRAY_BITS  4
58 #define CT_LOCKARRAY_SIZE  (1<<CT_LOCKARRAY_BITS)
59 #define CT_LOCKARRAY_MASK  (CT_LOCKARRAY_SIZE-1)
60
61 struct ip_vs_aligned_lock
62 {
63         rwlock_t        l;
64 } __attribute__((__aligned__(SMP_CACHE_BYTES)));
65
66 /* lock array for conn table */
67 static struct ip_vs_aligned_lock
68 __ip_vs_conntbl_lock_array[CT_LOCKARRAY_SIZE] __cacheline_aligned;
69
70 static inline void ct_read_lock(unsigned key)
71 {
72         read_lock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
73 }
74
75 static inline void ct_read_unlock(unsigned key)
76 {
77         read_unlock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
78 }
79
80 static inline void ct_write_lock(unsigned key)
81 {
82         write_lock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
83 }
84
85 static inline void ct_write_unlock(unsigned key)
86 {
87         write_unlock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
88 }
89
90 static inline void ct_read_lock_bh(unsigned key)
91 {
92         read_lock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
93 }
94
95 static inline void ct_read_unlock_bh(unsigned key)
96 {
97         read_unlock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
98 }
99
100 static inline void ct_write_lock_bh(unsigned key)
101 {
102         write_lock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
103 }
104
105 static inline void ct_write_unlock_bh(unsigned key)
106 {
107         write_unlock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
108 }
109
110
111 /*
112  *      Returns hash value for IPVS connection entry
113  */
114 static unsigned int ip_vs_conn_hashkey(unsigned proto, __u32 addr, __u16 port)
115 {
116         return jhash_3words(addr, port, proto, ip_vs_conn_rnd)
117                 & IP_VS_CONN_TAB_MASK;
118 }
119
120
121 /*
122  *      Hashes ip_vs_conn in ip_vs_conn_tab by proto,addr,port.
123  *      returns bool success.
124  */
125 static inline int ip_vs_conn_hash(struct ip_vs_conn *cp)
126 {
127         unsigned hash;
128         int ret;
129
130         /* Hash by protocol, client address and port */
131         hash = ip_vs_conn_hashkey(cp->protocol, cp->caddr, cp->cport);
132
133         ct_write_lock(hash);
134
135         if (!(cp->flags & IP_VS_CONN_F_HASHED)) {
136                 list_add(&cp->c_list, &ip_vs_conn_tab[hash]);
137                 cp->flags |= IP_VS_CONN_F_HASHED;
138                 atomic_inc(&cp->refcnt);
139                 ret = 1;
140         } else {
141                 IP_VS_ERR("ip_vs_conn_hash(): request for already hashed, "
142                           "called from %p\n", __builtin_return_address(0));
143                 ret = 0;
144         }
145
146         ct_write_unlock(hash);
147
148         return ret;
149 }
150
151
152 /*
153  *      UNhashes ip_vs_conn from ip_vs_conn_tab.
154  *      returns bool success.
155  */
156 static inline int ip_vs_conn_unhash(struct ip_vs_conn *cp)
157 {
158         unsigned hash;
159         int ret;
160
161         /* unhash it and decrease its reference counter */
162         hash = ip_vs_conn_hashkey(cp->protocol, cp->caddr, cp->cport);
163
164         ct_write_lock(hash);
165
166         if (cp->flags & IP_VS_CONN_F_HASHED) {
167                 list_del(&cp->c_list);
168                 cp->flags &= ~IP_VS_CONN_F_HASHED;
169                 atomic_dec(&cp->refcnt);
170                 ret = 1;
171         } else
172                 ret = 0;
173
174         ct_write_unlock(hash);
175
176         return ret;
177 }
178
179
180 /*
181  *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
182  *  Called for pkts coming from OUTside-to-INside.
183  *      s_addr, s_port: pkt source address (foreign host)
184  *      d_addr, d_port: pkt dest address (load balancer)
185  */
186 static inline struct ip_vs_conn *__ip_vs_conn_in_get
187 (int protocol, __u32 s_addr, __u16 s_port, __u32 d_addr, __u16 d_port)
188 {
189         unsigned hash;
190         struct ip_vs_conn *cp;
191
192         hash = ip_vs_conn_hashkey(protocol, s_addr, s_port);
193
194         ct_read_lock(hash);
195
196         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
197                 if (s_addr==cp->caddr && s_port==cp->cport &&
198                     d_port==cp->vport && d_addr==cp->vaddr &&
199                     protocol==cp->protocol) {
200                         /* HIT */
201                         atomic_inc(&cp->refcnt);
202                         ct_read_unlock(hash);
203                         return cp;
204                 }
205         }
206
207         ct_read_unlock(hash);
208
209         return NULL;
210 }
211
212 struct ip_vs_conn *ip_vs_conn_in_get
213 (int protocol, __u32 s_addr, __u16 s_port, __u32 d_addr, __u16 d_port)
214 {
215         struct ip_vs_conn *cp;
216
217         cp = __ip_vs_conn_in_get(protocol, s_addr, s_port, d_addr, d_port);
218         if (!cp && atomic_read(&ip_vs_conn_no_cport_cnt))
219                 cp = __ip_vs_conn_in_get(protocol, s_addr, 0, d_addr, d_port);
220
221         IP_VS_DBG(7, "lookup/in %s %u.%u.%u.%u:%d->%u.%u.%u.%u:%d %s\n",
222                   ip_vs_proto_name(protocol),
223                   NIPQUAD(s_addr), ntohs(s_port),
224                   NIPQUAD(d_addr), ntohs(d_port),
225                   cp?"hit":"not hit");
226
227         return cp;
228 }
229
230
231 /*
232  *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
233  *  Called for pkts coming from inside-to-OUTside.
234  *      s_addr, s_port: pkt source address (inside host)
235  *      d_addr, d_port: pkt dest address (foreign host)
236  */
237 struct ip_vs_conn *ip_vs_conn_out_get
238 (int protocol, __u32 s_addr, __u16 s_port, __u32 d_addr, __u16 d_port)
239 {
240         unsigned hash;
241         struct ip_vs_conn *cp, *ret=NULL;
242
243         /*
244          *      Check for "full" addressed entries
245          */
246         hash = ip_vs_conn_hashkey(protocol, d_addr, d_port);
247
248         ct_read_lock(hash);
249
250         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
251                 if (d_addr == cp->caddr && d_port == cp->cport &&
252                     s_port == cp->dport && s_addr == cp->daddr &&
253                     protocol == cp->protocol) {
254                         /* HIT */
255                         atomic_inc(&cp->refcnt);
256                         ret = cp;
257                         break;
258                 }
259         }
260
261         ct_read_unlock(hash);
262
263         IP_VS_DBG(7, "lookup/out %s %u.%u.%u.%u:%d->%u.%u.%u.%u:%d %s\n",
264                   ip_vs_proto_name(protocol),
265                   NIPQUAD(s_addr), ntohs(s_port),
266                   NIPQUAD(d_addr), ntohs(d_port),
267                   ret?"hit":"not hit");
268
269         return ret;
270 }
271
272
273 /*
274  *      Put back the conn and restart its timer with its timeout
275  */
276 void ip_vs_conn_put(struct ip_vs_conn *cp)
277 {
278         /* reset it expire in its timeout */
279         mod_timer(&cp->timer, jiffies+cp->timeout);
280
281         __ip_vs_conn_put(cp);
282 }
283
284
285 /*
286  *      Fill a no_client_port connection with a client port number
287  */
288 void ip_vs_conn_fill_cport(struct ip_vs_conn *cp, __u16 cport)
289 {
290         if (ip_vs_conn_unhash(cp)) {
291                 spin_lock(&cp->lock);
292                 if (cp->flags & IP_VS_CONN_F_NO_CPORT) {
293                         atomic_dec(&ip_vs_conn_no_cport_cnt);
294                         cp->flags &= ~IP_VS_CONN_F_NO_CPORT;
295                         cp->cport = cport;
296                 }
297                 spin_unlock(&cp->lock);
298
299                 /* hash on new dport */
300                 ip_vs_conn_hash(cp);
301         }
302 }
303
304
305 /*
306  *      Bind a connection entry with the corresponding packet_xmit.
307  *      Called by ip_vs_conn_new.
308  */
309 static inline void ip_vs_bind_xmit(struct ip_vs_conn *cp)
310 {
311         switch (IP_VS_FWD_METHOD(cp)) {
312         case IP_VS_CONN_F_MASQ:
313                 cp->packet_xmit = ip_vs_nat_xmit;
314                 break;
315
316         case IP_VS_CONN_F_TUNNEL:
317                 cp->packet_xmit = ip_vs_tunnel_xmit;
318                 break;
319
320         case IP_VS_CONN_F_DROUTE:
321                 cp->packet_xmit = ip_vs_dr_xmit;
322                 break;
323
324         case IP_VS_CONN_F_LOCALNODE:
325                 cp->packet_xmit = ip_vs_null_xmit;
326                 break;
327
328         case IP_VS_CONN_F_BYPASS:
329                 cp->packet_xmit = ip_vs_bypass_xmit;
330                 break;
331         }
332 }
333
334
335 static inline int ip_vs_dest_totalconns(struct ip_vs_dest *dest)
336 {
337         return atomic_read(&dest->activeconns)
338                 + atomic_read(&dest->inactconns);
339 }
340
341 /*
342  *      Bind a connection entry with a virtual service destination
343  *      Called just after a new connection entry is created.
344  */
345 static inline void
346 ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest *dest)
347 {
348         /* if dest is NULL, then return directly */
349         if (!dest)
350                 return;
351
352         /* Increase the refcnt counter of the dest */
353         atomic_inc(&dest->refcnt);
354
355         /* Bind with the destination and its corresponding transmitter */
356         cp->flags |= atomic_read(&dest->conn_flags);
357         cp->dest = dest;
358
359         IP_VS_DBG(9, "Bind-dest %s c:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
360                   "d:%u.%u.%u.%u:%d fwd:%c s:%u flg:%X cnt:%d destcnt:%d\n",
361                   ip_vs_proto_name(cp->protocol),
362                   NIPQUAD(cp->caddr), ntohs(cp->cport),
363                   NIPQUAD(cp->vaddr), ntohs(cp->vport),
364                   NIPQUAD(cp->daddr), ntohs(cp->dport),
365                   ip_vs_fwd_tag(cp), cp->state,
366                   cp->flags, atomic_read(&cp->refcnt),
367                   atomic_read(&dest->refcnt));
368
369         /* Update the connection counters */
370         if (cp->cport || (cp->flags & IP_VS_CONN_F_NO_CPORT)) {
371                 /* It is a normal connection, so increase the inactive
372                    connection counter because it is in TCP SYNRECV
373                    state (inactive) or other protocol inacive state */
374                 atomic_inc(&dest->inactconns);
375         } else {
376                 /* It is a persistent connection/template, so increase
377                    the peristent connection counter */
378                 atomic_inc(&dest->persistconns);
379         }
380
381         if (dest->u_threshold != 0 &&
382             ip_vs_dest_totalconns(dest) >= dest->u_threshold)
383                 dest->flags |= IP_VS_DEST_F_OVERLOAD;
384 }
385
386
387 /*
388  *      Unbind a connection entry with its VS destination
389  *      Called by the ip_vs_conn_expire function.
390  */
391 static inline void ip_vs_unbind_dest(struct ip_vs_conn *cp)
392 {
393         struct ip_vs_dest *dest = cp->dest;
394
395         if (!dest)
396                 return;
397
398         IP_VS_DBG(9, "Unbind-dest %s c:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
399                   "d:%u.%u.%u.%u:%d fwd:%c s:%u flg:%X cnt:%d destcnt:%d\n",
400                   ip_vs_proto_name(cp->protocol),
401                   NIPQUAD(cp->caddr), ntohs(cp->cport),
402                   NIPQUAD(cp->vaddr), ntohs(cp->vport),
403                   NIPQUAD(cp->daddr), ntohs(cp->dport),
404                   ip_vs_fwd_tag(cp), cp->state,
405                   cp->flags, atomic_read(&cp->refcnt),
406                   atomic_read(&dest->refcnt));
407
408         /* Update the connection counters */
409         if (cp->cport || (cp->flags & IP_VS_CONN_F_NO_CPORT)) {
410                 /* It is a normal connection, so decrease the inactconns
411                    or activeconns counter */
412                 if (cp->flags & IP_VS_CONN_F_INACTIVE) {
413                         atomic_dec(&dest->inactconns);
414                 } else {
415                         atomic_dec(&dest->activeconns);
416                 }
417         } else {
418                 /* It is a persistent connection/template, so decrease
419                    the peristent connection counter */
420                 atomic_dec(&dest->persistconns);
421         }
422
423         if (dest->l_threshold != 0) {
424                 if (ip_vs_dest_totalconns(dest) < dest->l_threshold)
425                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
426         } else if (dest->u_threshold != 0) {
427                 if (ip_vs_dest_totalconns(dest) * 4 < dest->u_threshold * 3)
428                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
429         } else {
430                 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
431                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
432         }
433
434         /*
435          * Simply decrease the refcnt of the dest, because the
436          * dest will be either in service's destination list
437          * or in the trash.
438          */
439         atomic_dec(&dest->refcnt);
440 }
441
442
443 /*
444  *      Checking if the destination of a connection template is available.
445  *      If available, return 1, otherwise invalidate this connection
446  *      template and return 0.
447  */
448 int ip_vs_check_template(struct ip_vs_conn *ct)
449 {
450         struct ip_vs_dest *dest = ct->dest;
451
452         /*
453          * Checking the dest server status.
454          */
455         if ((dest == NULL) ||
456             !(dest->flags & IP_VS_DEST_F_AVAILABLE) || 
457             (sysctl_ip_vs_expire_quiescent_template && 
458              (atomic_read(&dest->weight) == 0))) {
459                 IP_VS_DBG(9, "check_template: dest not available for "
460                           "protocol %s s:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
461                           "-> d:%u.%u.%u.%u:%d\n",
462                           ip_vs_proto_name(ct->protocol),
463                           NIPQUAD(ct->caddr), ntohs(ct->cport),
464                           NIPQUAD(ct->vaddr), ntohs(ct->vport),
465                           NIPQUAD(ct->daddr), ntohs(ct->dport));
466
467                 /*
468                  * Invalidate the connection template
469                  */
470                 if (ct->cport) {
471                         if (ip_vs_conn_unhash(ct)) {
472                                 ct->dport = 65535;
473                                 ct->vport = 65535;
474                                 ct->cport = 0;
475                                 ip_vs_conn_hash(ct);
476                         }
477                 }
478
479                 /*
480                  * Simply decrease the refcnt of the template,
481                  * don't restart its timer.
482                  */
483                 atomic_dec(&ct->refcnt);
484                 return 0;
485         }
486         return 1;
487 }
488
489 static void ip_vs_conn_expire(unsigned long data)
490 {
491         struct ip_vs_conn *cp = (struct ip_vs_conn *)data;
492
493         cp->timeout = 60*HZ;
494
495         /*
496          *      hey, I'm using it
497          */
498         atomic_inc(&cp->refcnt);
499
500         /*
501          *      do I control anybody?
502          */
503         if (atomic_read(&cp->n_control))
504                 goto expire_later;
505
506         /*
507          *      unhash it if it is hashed in the conn table
508          */
509         if (!ip_vs_conn_unhash(cp))
510                 goto expire_later;
511
512         /*
513          *      refcnt==1 implies I'm the only one referrer
514          */
515         if (likely(atomic_read(&cp->refcnt) == 1)) {
516                 /* delete the timer if it is activated by other users */
517                 if (timer_pending(&cp->timer))
518                         del_timer(&cp->timer);
519
520                 /* does anybody control me? */
521                 if (cp->control)
522                         ip_vs_control_del(cp);
523
524                 if (unlikely(cp->app != NULL))
525                         ip_vs_unbind_app(cp);
526                 ip_vs_unbind_dest(cp);
527                 if (cp->flags & IP_VS_CONN_F_NO_CPORT)
528                         atomic_dec(&ip_vs_conn_no_cport_cnt);
529                 atomic_dec(&ip_vs_conn_count);
530
531                 kmem_cache_free(ip_vs_conn_cachep, cp);
532                 return;
533         }
534
535         /* hash it back to the table */
536         ip_vs_conn_hash(cp);
537
538   expire_later:
539         IP_VS_DBG(7, "delayed: refcnt-1=%d conn.n_control=%d\n",
540                   atomic_read(&cp->refcnt)-1,
541                   atomic_read(&cp->n_control));
542
543         ip_vs_conn_put(cp);
544 }
545
546
547 void ip_vs_conn_expire_now(struct ip_vs_conn *cp)
548 {
549         if (del_timer(&cp->timer))
550                 mod_timer(&cp->timer, jiffies);
551         __ip_vs_conn_put(cp);
552 }
553
554
555 /*
556  *      Create a new connection entry and hash it into the ip_vs_conn_tab
557  */
558 struct ip_vs_conn *
559 ip_vs_conn_new(int proto, __u32 caddr, __u16 cport, __u32 vaddr, __u16 vport,
560                __u32 daddr, __u16 dport, unsigned flags,
561                struct ip_vs_dest *dest)
562 {
563         struct ip_vs_conn *cp;
564         struct ip_vs_protocol *pp = ip_vs_proto_get(proto);
565
566         cp = kmem_cache_alloc(ip_vs_conn_cachep, GFP_ATOMIC);
567         if (cp == NULL) {
568                 IP_VS_ERR_RL("ip_vs_conn_new: no memory available.\n");
569                 return NULL;
570         }
571
572         memset(cp, 0, sizeof(*cp));
573         INIT_LIST_HEAD(&cp->c_list);
574         init_timer(&cp->timer);
575         cp->timer.data     = (unsigned long)cp;
576         cp->timer.function = ip_vs_conn_expire;
577         cp->protocol       = proto;
578         cp->caddr          = caddr;
579         cp->cport          = cport;
580         cp->vaddr          = vaddr;
581         cp->vport          = vport;
582         cp->daddr          = daddr;
583         cp->dport          = dport;
584         cp->flags          = flags;
585         spin_lock_init(&cp->lock);
586
587         /*
588          * Set the entry is referenced by the current thread before hashing
589          * it in the table, so that other thread run ip_vs_random_dropentry
590          * but cannot drop this entry.
591          */
592         atomic_set(&cp->refcnt, 1);
593
594         atomic_set(&cp->n_control, 0);
595         atomic_set(&cp->in_pkts, 0);
596
597         atomic_inc(&ip_vs_conn_count);
598         if (flags & IP_VS_CONN_F_NO_CPORT)
599                 atomic_inc(&ip_vs_conn_no_cport_cnt);
600
601         /* Bind the connection with a destination server */
602         ip_vs_bind_dest(cp, dest);
603
604         /* Set its state and timeout */
605         cp->state = 0;
606         cp->timeout = 3*HZ;
607
608         /* Bind its packet transmitter */
609         ip_vs_bind_xmit(cp);
610
611         if (unlikely(pp && atomic_read(&pp->appcnt)))
612                 ip_vs_bind_app(cp, pp);
613
614         /* Hash it in the ip_vs_conn_tab finally */
615         ip_vs_conn_hash(cp);
616
617         return cp;
618 }
619
620
621 /*
622  *      /proc/net/ip_vs_conn entries
623  */
624 #ifdef CONFIG_PROC_FS
625
626 static void *ip_vs_conn_array(struct seq_file *seq, loff_t pos)
627 {
628         int idx;
629         struct ip_vs_conn *cp;
630         
631         for(idx = 0; idx < IP_VS_CONN_TAB_SIZE; idx++) {
632                 ct_read_lock_bh(idx);
633                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
634                         if (pos-- == 0) {
635                                 seq->private = &ip_vs_conn_tab[idx];
636                                 return cp;
637                         }
638                 }
639                 ct_read_unlock_bh(idx);
640         }
641
642         return NULL;
643 }
644
645 static void *ip_vs_conn_seq_start(struct seq_file *seq, loff_t *pos)
646 {
647         seq->private = NULL;
648         return *pos ? ip_vs_conn_array(seq, *pos - 1) :SEQ_START_TOKEN;
649 }
650
651 static void *ip_vs_conn_seq_next(struct seq_file *seq, void *v, loff_t *pos)
652 {
653         struct ip_vs_conn *cp = v;
654         struct list_head *e, *l = seq->private;
655         int idx;
656
657         ++*pos;
658         if (v == SEQ_START_TOKEN) 
659                 return ip_vs_conn_array(seq, 0);
660
661         /* more on same hash chain? */
662         if ((e = cp->c_list.next) != l)
663                 return list_entry(e, struct ip_vs_conn, c_list);
664
665         idx = l - ip_vs_conn_tab;
666         ct_read_unlock_bh(idx);
667
668         while (++idx < IP_VS_CONN_TAB_SIZE) {
669                 ct_read_lock_bh(idx);
670                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
671                         seq->private = &ip_vs_conn_tab[idx];
672                         return cp;
673                 }       
674                 ct_read_unlock_bh(idx);
675         }
676         seq->private = NULL;
677         return NULL;
678 }
679
680 static void ip_vs_conn_seq_stop(struct seq_file *seq, void *v)
681 {
682         struct list_head *l = seq->private;
683
684         if (l)
685                 ct_read_unlock_bh(l - ip_vs_conn_tab);
686 }
687
688 static int ip_vs_conn_seq_show(struct seq_file *seq, void *v)
689 {
690
691         if (v == SEQ_START_TOKEN)
692                 seq_puts(seq,
693    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Expires\n");
694         else {
695                 const struct ip_vs_conn *cp = v;
696
697                 seq_printf(seq,
698                         "%-3s %08X %04X %08X %04X %08X %04X %-11s %7lu\n",
699                                 ip_vs_proto_name(cp->protocol),
700                                 ntohl(cp->caddr), ntohs(cp->cport),
701                                 ntohl(cp->vaddr), ntohs(cp->vport),
702                                 ntohl(cp->daddr), ntohs(cp->dport),
703                                 ip_vs_state_name(cp->protocol, cp->state),
704                                 (cp->timer.expires-jiffies)/HZ);
705         }
706         return 0;
707 }
708
709 static struct seq_operations ip_vs_conn_seq_ops = {
710         .start = ip_vs_conn_seq_start,
711         .next  = ip_vs_conn_seq_next,
712         .stop  = ip_vs_conn_seq_stop,
713         .show  = ip_vs_conn_seq_show,
714 };
715
716 static int ip_vs_conn_open(struct inode *inode, struct file *file)
717 {
718         return seq_open(file, &ip_vs_conn_seq_ops);
719 }
720
721 static struct file_operations ip_vs_conn_fops = {
722         .owner   = THIS_MODULE,
723         .open    = ip_vs_conn_open,
724         .read    = seq_read,
725         .llseek  = seq_lseek,
726         .release = seq_release,
727 };
728 #endif
729
730
731 /*
732  *      Randomly drop connection entries before running out of memory
733  */
734 static inline int todrop_entry(struct ip_vs_conn *cp)
735 {
736         /*
737          * The drop rate array needs tuning for real environments.
738          * Called from timer bh only => no locking
739          */
740         static char todrop_rate[9] = {0, 1, 2, 3, 4, 5, 6, 7, 8};
741         static char todrop_counter[9] = {0};
742         int i;
743
744         /* if the conn entry hasn't lasted for 60 seconds, don't drop it.
745            This will leave enough time for normal connection to get
746            through. */
747         if (time_before(cp->timeout + jiffies, cp->timer.expires + 60*HZ))
748                 return 0;
749
750         /* Don't drop the entry if its number of incoming packets is not
751            located in [0, 8] */
752         i = atomic_read(&cp->in_pkts);
753         if (i > 8 || i < 0) return 0;
754
755         if (!todrop_rate[i]) return 0;
756         if (--todrop_counter[i] > 0) return 0;
757
758         todrop_counter[i] = todrop_rate[i];
759         return 1;
760 }
761
762
763 void ip_vs_random_dropentry(void)
764 {
765         int idx;
766         struct ip_vs_conn *cp;
767         struct ip_vs_conn *ct;
768
769         /*
770          * Randomly scan 1/32 of the whole table every second
771          */
772         for (idx = 0; idx < (IP_VS_CONN_TAB_SIZE>>5); idx++) {
773                 unsigned hash = net_random() & IP_VS_CONN_TAB_MASK;
774
775                 /*
776                  *  Lock is actually needed in this loop.
777                  */
778                 ct_write_lock(hash);
779
780                 list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
781                         if (!cp->cport && !(cp->flags & IP_VS_CONN_F_NO_CPORT))
782                                 /* connection template */
783                                 continue;
784
785                         if (cp->protocol == IPPROTO_TCP) {
786                                 switch(cp->state) {
787                                 case IP_VS_TCP_S_SYN_RECV:
788                                 case IP_VS_TCP_S_SYNACK:
789                                         break;
790
791                                 case IP_VS_TCP_S_ESTABLISHED:
792                                         if (todrop_entry(cp))
793                                                 break;
794                                         continue;
795
796                                 default:
797                                         continue;
798                                 }
799                         } else {
800                                 if (!todrop_entry(cp))
801                                         continue;
802                         }
803
804                         /*
805                          * Drop the entry, and drop its ct if not referenced
806                          */
807                         atomic_inc(&cp->refcnt);
808                         ct_write_unlock(hash);
809
810                         if ((ct = cp->control))
811                                 atomic_inc(&ct->refcnt);
812                         IP_VS_DBG(4, "del connection\n");
813                         ip_vs_conn_expire_now(cp);
814                         if (ct) {
815                                 IP_VS_DBG(4, "del conn template\n");
816                                 ip_vs_conn_expire_now(ct);
817                         }
818                         ct_write_lock(hash);
819                 }
820                 ct_write_unlock(hash);
821         }
822 }
823
824
825 /*
826  *      Flush all the connection entries in the ip_vs_conn_tab
827  */
828 static void ip_vs_conn_flush(void)
829 {
830         int idx;
831         struct ip_vs_conn *cp;
832         struct ip_vs_conn *ct;
833
834   flush_again:
835         for (idx=0; idx<IP_VS_CONN_TAB_SIZE; idx++) {
836                 /*
837                  *  Lock is actually needed in this loop.
838                  */
839                 ct_write_lock_bh(idx);
840
841                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
842                         atomic_inc(&cp->refcnt);
843                         ct_write_unlock(idx);
844
845                         if ((ct = cp->control))
846                                 atomic_inc(&ct->refcnt);
847                         IP_VS_DBG(4, "del connection\n");
848                         ip_vs_conn_expire_now(cp);
849                         if (ct) {
850                                 IP_VS_DBG(4, "del conn template\n");
851                                 ip_vs_conn_expire_now(ct);
852                         }
853                         ct_write_lock(idx);
854                 }
855                 ct_write_unlock_bh(idx);
856         }
857
858         /* the counter may be not NULL, because maybe some conn entries
859            are run by slow timer handler or unhashed but still referred */
860         if (atomic_read(&ip_vs_conn_count) != 0) {
861                 schedule();
862                 goto flush_again;
863         }
864 }
865
866
867 int ip_vs_conn_init(void)
868 {
869         int idx;
870
871         /*
872          * Allocate the connection hash table and initialize its list heads
873          */
874         ip_vs_conn_tab = vmalloc(IP_VS_CONN_TAB_SIZE*sizeof(struct list_head));
875         if (!ip_vs_conn_tab)
876                 return -ENOMEM;
877
878         /* Allocate ip_vs_conn slab cache */
879         ip_vs_conn_cachep = kmem_cache_create("ip_vs_conn",
880                                               sizeof(struct ip_vs_conn), 0,
881                                               SLAB_HWCACHE_ALIGN, NULL, NULL);
882         if (!ip_vs_conn_cachep) {
883                 vfree(ip_vs_conn_tab);
884                 return -ENOMEM;
885         }
886
887         IP_VS_INFO("Connection hash table configured "
888                    "(size=%d, memory=%ldKbytes)\n",
889                    IP_VS_CONN_TAB_SIZE,
890                    (long)(IP_VS_CONN_TAB_SIZE*sizeof(struct list_head))/1024);
891         IP_VS_DBG(0, "Each connection entry needs %Zd bytes at least\n",
892                   sizeof(struct ip_vs_conn));
893
894         for (idx = 0; idx < IP_VS_CONN_TAB_SIZE; idx++) {
895                 INIT_LIST_HEAD(&ip_vs_conn_tab[idx]);
896         }
897
898         for (idx = 0; idx < CT_LOCKARRAY_SIZE; idx++)  {
899                 rwlock_init(&__ip_vs_conntbl_lock_array[idx].l);
900         }
901
902         proc_net_fops_create("ip_vs_conn", 0, &ip_vs_conn_fops);
903
904         /* calculate the random value for connection hash */
905         get_random_bytes(&ip_vs_conn_rnd, sizeof(ip_vs_conn_rnd));
906
907         return 0;
908 }
909
910
911 void ip_vs_conn_cleanup(void)
912 {
913         /* flush all the connection entries first */
914         ip_vs_conn_flush();
915
916         /* Release the empty cache */
917         kmem_cache_destroy(ip_vs_conn_cachep);
918         proc_net_remove("ip_vs_conn");
919         vfree(ip_vs_conn_tab);
920 }