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TOMOYO Linux Cross Reference
Linux/net/netfilter/ipvs/ip_vs_conn.c

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  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  * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
  9  *              Peter Kese <peter.kese@ijs.si>
 10  *              Julian Anastasov <ja@ssi.bg>
 11  *
 12  *              This program is free software; you can redistribute it and/or
 13  *              modify it under the terms of the GNU General Public License
 14  *              as published by the Free Software Foundation; either version
 15  *              2 of the License, or (at your option) any later version.
 16  *
 17  * The IPVS code for kernel 2.2 was done by Wensong Zhang and Peter Kese,
 18  * with changes/fixes from Julian Anastasov, Lars Marowsky-Bree, Horms
 19  * and others. Many code here is taken from IP MASQ code of kernel 2.2.
 20  *
 21  * Changes:
 22  *
 23  */
 24 
 25 #define KMSG_COMPONENT "IPVS"
 26 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 27 
 28 #include <linux/interrupt.h>
 29 #include <linux/in.h>
 30 #include <linux/inet.h>
 31 #include <linux/net.h>
 32 #include <linux/kernel.h>
 33 #include <linux/module.h>
 34 #include <linux/vmalloc.h>
 35 #include <linux/proc_fs.h>              /* for proc_net_* */
 36 #include <linux/slab.h>
 37 #include <linux/seq_file.h>
 38 #include <linux/jhash.h>
 39 #include <linux/random.h>
 40 
 41 #include <net/net_namespace.h>
 42 #include <net/ip_vs.h>
 43 
 44 
 45 #ifndef CONFIG_IP_VS_TAB_BITS
 46 #define CONFIG_IP_VS_TAB_BITS   12
 47 #endif
 48 
 49 /*
 50  * Connection hash size. Default is what was selected at compile time.
 51 */
 52 static int ip_vs_conn_tab_bits = CONFIG_IP_VS_TAB_BITS;
 53 module_param_named(conn_tab_bits, ip_vs_conn_tab_bits, int, 0444);
 54 MODULE_PARM_DESC(conn_tab_bits, "Set connections' hash size");
 55 
 56 /* size and mask values */
 57 int ip_vs_conn_tab_size __read_mostly;
 58 static int ip_vs_conn_tab_mask __read_mostly;
 59 
 60 /*
 61  *  Connection hash table: for input and output packets lookups of IPVS
 62  */
 63 static struct hlist_head *ip_vs_conn_tab __read_mostly;
 64 
 65 /*  SLAB cache for IPVS connections */
 66 static struct kmem_cache *ip_vs_conn_cachep __read_mostly;
 67 
 68 /*  counter for no client port connections */
 69 static atomic_t ip_vs_conn_no_cport_cnt = ATOMIC_INIT(0);
 70 
 71 /* random value for IPVS connection hash */
 72 static unsigned int ip_vs_conn_rnd __read_mostly;
 73 
 74 /*
 75  *  Fine locking granularity for big connection hash table
 76  */
 77 #define CT_LOCKARRAY_BITS  5
 78 #define CT_LOCKARRAY_SIZE  (1<<CT_LOCKARRAY_BITS)
 79 #define CT_LOCKARRAY_MASK  (CT_LOCKARRAY_SIZE-1)
 80 
 81 /* We need an addrstrlen that works with or without v6 */
 82 #ifdef CONFIG_IP_VS_IPV6
 83 #define IP_VS_ADDRSTRLEN INET6_ADDRSTRLEN
 84 #else
 85 #define IP_VS_ADDRSTRLEN (8+1)
 86 #endif
 87 
 88 struct ip_vs_aligned_lock
 89 {
 90         spinlock_t      l;
 91 } __attribute__((__aligned__(SMP_CACHE_BYTES)));
 92 
 93 /* lock array for conn table */
 94 static struct ip_vs_aligned_lock
 95 __ip_vs_conntbl_lock_array[CT_LOCKARRAY_SIZE] __cacheline_aligned;
 96 
 97 static inline void ct_write_lock_bh(unsigned int key)
 98 {
 99         spin_lock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
100 }
101 
102 static inline void ct_write_unlock_bh(unsigned int key)
103 {
104         spin_unlock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
105 }
106 
107 
108 /*
109  *      Returns hash value for IPVS connection entry
110  */
111 static unsigned int ip_vs_conn_hashkey(struct net *net, int af, unsigned int proto,
112                                        const union nf_inet_addr *addr,
113                                        __be16 port)
114 {
115 #ifdef CONFIG_IP_VS_IPV6
116         if (af == AF_INET6)
117                 return (jhash_3words(jhash(addr, 16, ip_vs_conn_rnd),
118                                     (__force u32)port, proto, ip_vs_conn_rnd) ^
119                         ((size_t)net>>8)) & ip_vs_conn_tab_mask;
120 #endif
121         return (jhash_3words((__force u32)addr->ip, (__force u32)port, proto,
122                             ip_vs_conn_rnd) ^
123                 ((size_t)net>>8)) & ip_vs_conn_tab_mask;
124 }
125 
126 static unsigned int ip_vs_conn_hashkey_param(const struct ip_vs_conn_param *p,
127                                              bool inverse)
128 {
129         const union nf_inet_addr *addr;
130         __be16 port;
131 
132         if (p->pe_data && p->pe->hashkey_raw)
133                 return p->pe->hashkey_raw(p, ip_vs_conn_rnd, inverse) &
134                         ip_vs_conn_tab_mask;
135 
136         if (likely(!inverse)) {
137                 addr = p->caddr;
138                 port = p->cport;
139         } else {
140                 addr = p->vaddr;
141                 port = p->vport;
142         }
143 
144         return ip_vs_conn_hashkey(p->net, p->af, p->protocol, addr, port);
145 }
146 
147 static unsigned int ip_vs_conn_hashkey_conn(const struct ip_vs_conn *cp)
148 {
149         struct ip_vs_conn_param p;
150 
151         ip_vs_conn_fill_param(ip_vs_conn_net(cp), cp->af, cp->protocol,
152                               &cp->caddr, cp->cport, NULL, 0, &p);
153 
154         if (cp->pe) {
155                 p.pe = cp->pe;
156                 p.pe_data = cp->pe_data;
157                 p.pe_data_len = cp->pe_data_len;
158         }
159 
160         return ip_vs_conn_hashkey_param(&p, false);
161 }
162 
163 /*
164  *      Hashes ip_vs_conn in ip_vs_conn_tab by netns,proto,addr,port.
165  *      returns bool success.
166  */
167 static inline int ip_vs_conn_hash(struct ip_vs_conn *cp)
168 {
169         unsigned int hash;
170         int ret;
171 
172         if (cp->flags & IP_VS_CONN_F_ONE_PACKET)
173                 return 0;
174 
175         /* Hash by protocol, client address and port */
176         hash = ip_vs_conn_hashkey_conn(cp);
177 
178         ct_write_lock_bh(hash);
179         spin_lock(&cp->lock);
180 
181         if (!(cp->flags & IP_VS_CONN_F_HASHED)) {
182                 cp->flags |= IP_VS_CONN_F_HASHED;
183                 atomic_inc(&cp->refcnt);
184                 hlist_add_head_rcu(&cp->c_list, &ip_vs_conn_tab[hash]);
185                 ret = 1;
186         } else {
187                 pr_err("%s(): request for already hashed, called from %pF\n",
188                        __func__, __builtin_return_address(0));
189                 ret = 0;
190         }
191 
192         spin_unlock(&cp->lock);
193         ct_write_unlock_bh(hash);
194 
195         return ret;
196 }
197 
198 
199 /*
200  *      UNhashes ip_vs_conn from ip_vs_conn_tab.
201  *      returns bool success. Caller should hold conn reference.
202  */
203 static inline int ip_vs_conn_unhash(struct ip_vs_conn *cp)
204 {
205         unsigned int hash;
206         int ret;
207 
208         /* unhash it and decrease its reference counter */
209         hash = ip_vs_conn_hashkey_conn(cp);
210 
211         ct_write_lock_bh(hash);
212         spin_lock(&cp->lock);
213 
214         if (cp->flags & IP_VS_CONN_F_HASHED) {
215                 hlist_del_rcu(&cp->c_list);
216                 cp->flags &= ~IP_VS_CONN_F_HASHED;
217                 atomic_dec(&cp->refcnt);
218                 ret = 1;
219         } else
220                 ret = 0;
221 
222         spin_unlock(&cp->lock);
223         ct_write_unlock_bh(hash);
224 
225         return ret;
226 }
227 
228 /* Try to unlink ip_vs_conn from ip_vs_conn_tab.
229  * returns bool success.
230  */
231 static inline bool ip_vs_conn_unlink(struct ip_vs_conn *cp)
232 {
233         unsigned int hash;
234         bool ret;
235 
236         hash = ip_vs_conn_hashkey_conn(cp);
237 
238         ct_write_lock_bh(hash);
239         spin_lock(&cp->lock);
240 
241         if (cp->flags & IP_VS_CONN_F_HASHED) {
242                 ret = false;
243                 /* Decrease refcnt and unlink conn only if we are last user */
244                 if (atomic_cmpxchg(&cp->refcnt, 1, 0) == 1) {
245                         hlist_del_rcu(&cp->c_list);
246                         cp->flags &= ~IP_VS_CONN_F_HASHED;
247                         ret = true;
248                 }
249         } else
250                 ret = atomic_read(&cp->refcnt) ? false : true;
251 
252         spin_unlock(&cp->lock);
253         ct_write_unlock_bh(hash);
254 
255         return ret;
256 }
257 
258 
259 /*
260  *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
261  *  Called for pkts coming from OUTside-to-INside.
262  *      p->caddr, p->cport: pkt source address (foreign host)
263  *      p->vaddr, p->vport: pkt dest address (load balancer)
264  */
265 static inline struct ip_vs_conn *
266 __ip_vs_conn_in_get(const struct ip_vs_conn_param *p)
267 {
268         unsigned int hash;
269         struct ip_vs_conn *cp;
270 
271         hash = ip_vs_conn_hashkey_param(p, false);
272 
273         rcu_read_lock();
274 
275         hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[hash], c_list) {
276                 if (p->cport == cp->cport && p->vport == cp->vport &&
277                     cp->af == p->af &&
278                     ip_vs_addr_equal(p->af, p->caddr, &cp->caddr) &&
279                     ip_vs_addr_equal(p->af, p->vaddr, &cp->vaddr) &&
280                     ((!p->cport) ^ (!(cp->flags & IP_VS_CONN_F_NO_CPORT))) &&
281                     p->protocol == cp->protocol &&
282                     ip_vs_conn_net_eq(cp, p->net)) {
283                         if (!__ip_vs_conn_get(cp))
284                                 continue;
285                         /* HIT */
286                         rcu_read_unlock();
287                         return cp;
288                 }
289         }
290 
291         rcu_read_unlock();
292 
293         return NULL;
294 }
295 
296 struct ip_vs_conn *ip_vs_conn_in_get(const struct ip_vs_conn_param *p)
297 {
298         struct ip_vs_conn *cp;
299 
300         cp = __ip_vs_conn_in_get(p);
301         if (!cp && atomic_read(&ip_vs_conn_no_cport_cnt)) {
302                 struct ip_vs_conn_param cport_zero_p = *p;
303                 cport_zero_p.cport = 0;
304                 cp = __ip_vs_conn_in_get(&cport_zero_p);
305         }
306 
307         IP_VS_DBG_BUF(9, "lookup/in %s %s:%d->%s:%d %s\n",
308                       ip_vs_proto_name(p->protocol),
309                       IP_VS_DBG_ADDR(p->af, p->caddr), ntohs(p->cport),
310                       IP_VS_DBG_ADDR(p->af, p->vaddr), ntohs(p->vport),
311                       cp ? "hit" : "not hit");
312 
313         return cp;
314 }
315 
316 static int
317 ip_vs_conn_fill_param_proto(int af, const struct sk_buff *skb,
318                             const struct ip_vs_iphdr *iph,
319                             int inverse, struct ip_vs_conn_param *p)
320 {
321         __be16 _ports[2], *pptr;
322         struct net *net = skb_net(skb);
323 
324         pptr = frag_safe_skb_hp(skb, iph->len, sizeof(_ports), _ports, iph);
325         if (pptr == NULL)
326                 return 1;
327 
328         if (likely(!inverse))
329                 ip_vs_conn_fill_param(net, af, iph->protocol, &iph->saddr,
330                                       pptr[0], &iph->daddr, pptr[1], p);
331         else
332                 ip_vs_conn_fill_param(net, af, iph->protocol, &iph->daddr,
333                                       pptr[1], &iph->saddr, pptr[0], p);
334         return 0;
335 }
336 
337 struct ip_vs_conn *
338 ip_vs_conn_in_get_proto(int af, const struct sk_buff *skb,
339                         const struct ip_vs_iphdr *iph, int inverse)
340 {
341         struct ip_vs_conn_param p;
342 
343         if (ip_vs_conn_fill_param_proto(af, skb, iph, inverse, &p))
344                 return NULL;
345 
346         return ip_vs_conn_in_get(&p);
347 }
348 EXPORT_SYMBOL_GPL(ip_vs_conn_in_get_proto);
349 
350 /* Get reference to connection template */
351 struct ip_vs_conn *ip_vs_ct_in_get(const struct ip_vs_conn_param *p)
352 {
353         unsigned int hash;
354         struct ip_vs_conn *cp;
355 
356         hash = ip_vs_conn_hashkey_param(p, false);
357 
358         rcu_read_lock();
359 
360         hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[hash], c_list) {
361                 if (unlikely(p->pe_data && p->pe->ct_match)) {
362                         if (!ip_vs_conn_net_eq(cp, p->net))
363                                 continue;
364                         if (p->pe == cp->pe && p->pe->ct_match(p, cp)) {
365                                 if (__ip_vs_conn_get(cp))
366                                         goto out;
367                         }
368                         continue;
369                 }
370 
371                 if (cp->af == p->af &&
372                     ip_vs_addr_equal(p->af, p->caddr, &cp->caddr) &&
373                     /* protocol should only be IPPROTO_IP if
374                      * p->vaddr is a fwmark */
375                     ip_vs_addr_equal(p->protocol == IPPROTO_IP ? AF_UNSPEC :
376                                      p->af, p->vaddr, &cp->vaddr) &&
377                     p->vport == cp->vport && p->cport == cp->cport &&
378                     cp->flags & IP_VS_CONN_F_TEMPLATE &&
379                     p->protocol == cp->protocol &&
380                     ip_vs_conn_net_eq(cp, p->net)) {
381                         if (__ip_vs_conn_get(cp))
382                                 goto out;
383                 }
384         }
385         cp = NULL;
386 
387   out:
388         rcu_read_unlock();
389 
390         IP_VS_DBG_BUF(9, "template lookup/in %s %s:%d->%s:%d %s\n",
391                       ip_vs_proto_name(p->protocol),
392                       IP_VS_DBG_ADDR(p->af, p->caddr), ntohs(p->cport),
393                       IP_VS_DBG_ADDR(p->af, p->vaddr), ntohs(p->vport),
394                       cp ? "hit" : "not hit");
395 
396         return cp;
397 }
398 
399 /* Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
400  * Called for pkts coming from inside-to-OUTside.
401  *      p->caddr, p->cport: pkt source address (inside host)
402  *      p->vaddr, p->vport: pkt dest address (foreign host) */
403 struct ip_vs_conn *ip_vs_conn_out_get(const struct ip_vs_conn_param *p)
404 {
405         unsigned int hash;
406         struct ip_vs_conn *cp, *ret=NULL;
407 
408         /*
409          *      Check for "full" addressed entries
410          */
411         hash = ip_vs_conn_hashkey_param(p, true);
412 
413         rcu_read_lock();
414 
415         hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[hash], c_list) {
416                 if (p->vport == cp->cport && p->cport == cp->dport &&
417                     cp->af == p->af &&
418                     ip_vs_addr_equal(p->af, p->vaddr, &cp->caddr) &&
419                     ip_vs_addr_equal(p->af, p->caddr, &cp->daddr) &&
420                     p->protocol == cp->protocol &&
421                     ip_vs_conn_net_eq(cp, p->net)) {
422                         if (!__ip_vs_conn_get(cp))
423                                 continue;
424                         /* HIT */
425                         ret = cp;
426                         break;
427                 }
428         }
429 
430         rcu_read_unlock();
431 
432         IP_VS_DBG_BUF(9, "lookup/out %s %s:%d->%s:%d %s\n",
433                       ip_vs_proto_name(p->protocol),
434                       IP_VS_DBG_ADDR(p->af, p->caddr), ntohs(p->cport),
435                       IP_VS_DBG_ADDR(p->af, p->vaddr), ntohs(p->vport),
436                       ret ? "hit" : "not hit");
437 
438         return ret;
439 }
440 
441 struct ip_vs_conn *
442 ip_vs_conn_out_get_proto(int af, const struct sk_buff *skb,
443                          const struct ip_vs_iphdr *iph, int inverse)
444 {
445         struct ip_vs_conn_param p;
446 
447         if (ip_vs_conn_fill_param_proto(af, skb, iph, inverse, &p))
448                 return NULL;
449 
450         return ip_vs_conn_out_get(&p);
451 }
452 EXPORT_SYMBOL_GPL(ip_vs_conn_out_get_proto);
453 
454 /*
455  *      Put back the conn and restart its timer with its timeout
456  */
457 void ip_vs_conn_put(struct ip_vs_conn *cp)
458 {
459         unsigned long t = (cp->flags & IP_VS_CONN_F_ONE_PACKET) ?
460                 0 : cp->timeout;
461         mod_timer(&cp->timer, jiffies+t);
462 
463         __ip_vs_conn_put(cp);
464 }
465 
466 
467 /*
468  *      Fill a no_client_port connection with a client port number
469  */
470 void ip_vs_conn_fill_cport(struct ip_vs_conn *cp, __be16 cport)
471 {
472         if (ip_vs_conn_unhash(cp)) {
473                 spin_lock_bh(&cp->lock);
474                 if (cp->flags & IP_VS_CONN_F_NO_CPORT) {
475                         atomic_dec(&ip_vs_conn_no_cport_cnt);
476                         cp->flags &= ~IP_VS_CONN_F_NO_CPORT;
477                         cp->cport = cport;
478                 }
479                 spin_unlock_bh(&cp->lock);
480 
481                 /* hash on new dport */
482                 ip_vs_conn_hash(cp);
483         }
484 }
485 
486 
487 /*
488  *      Bind a connection entry with the corresponding packet_xmit.
489  *      Called by ip_vs_conn_new.
490  */
491 static inline void ip_vs_bind_xmit(struct ip_vs_conn *cp)
492 {
493         switch (IP_VS_FWD_METHOD(cp)) {
494         case IP_VS_CONN_F_MASQ:
495                 cp->packet_xmit = ip_vs_nat_xmit;
496                 break;
497 
498         case IP_VS_CONN_F_TUNNEL:
499 #ifdef CONFIG_IP_VS_IPV6
500                 if (cp->daf == AF_INET6)
501                         cp->packet_xmit = ip_vs_tunnel_xmit_v6;
502                 else
503 #endif
504                         cp->packet_xmit = ip_vs_tunnel_xmit;
505                 break;
506 
507         case IP_VS_CONN_F_DROUTE:
508                 cp->packet_xmit = ip_vs_dr_xmit;
509                 break;
510 
511         case IP_VS_CONN_F_LOCALNODE:
512                 cp->packet_xmit = ip_vs_null_xmit;
513                 break;
514 
515         case IP_VS_CONN_F_BYPASS:
516                 cp->packet_xmit = ip_vs_bypass_xmit;
517                 break;
518         }
519 }
520 
521 #ifdef CONFIG_IP_VS_IPV6
522 static inline void ip_vs_bind_xmit_v6(struct ip_vs_conn *cp)
523 {
524         switch (IP_VS_FWD_METHOD(cp)) {
525         case IP_VS_CONN_F_MASQ:
526                 cp->packet_xmit = ip_vs_nat_xmit_v6;
527                 break;
528 
529         case IP_VS_CONN_F_TUNNEL:
530                 if (cp->daf == AF_INET6)
531                         cp->packet_xmit = ip_vs_tunnel_xmit_v6;
532                 else
533                         cp->packet_xmit = ip_vs_tunnel_xmit;
534                 break;
535 
536         case IP_VS_CONN_F_DROUTE:
537                 cp->packet_xmit = ip_vs_dr_xmit_v6;
538                 break;
539 
540         case IP_VS_CONN_F_LOCALNODE:
541                 cp->packet_xmit = ip_vs_null_xmit;
542                 break;
543 
544         case IP_VS_CONN_F_BYPASS:
545                 cp->packet_xmit = ip_vs_bypass_xmit_v6;
546                 break;
547         }
548 }
549 #endif
550 
551 
552 static inline int ip_vs_dest_totalconns(struct ip_vs_dest *dest)
553 {
554         return atomic_read(&dest->activeconns)
555                 + atomic_read(&dest->inactconns);
556 }
557 
558 /*
559  *      Bind a connection entry with a virtual service destination
560  *      Called just after a new connection entry is created.
561  */
562 static inline void
563 ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest *dest)
564 {
565         unsigned int conn_flags;
566         __u32 flags;
567 
568         /* if dest is NULL, then return directly */
569         if (!dest)
570                 return;
571 
572         /* Increase the refcnt counter of the dest */
573         ip_vs_dest_hold(dest);
574 
575         conn_flags = atomic_read(&dest->conn_flags);
576         if (cp->protocol != IPPROTO_UDP)
577                 conn_flags &= ~IP_VS_CONN_F_ONE_PACKET;
578         flags = cp->flags;
579         /* Bind with the destination and its corresponding transmitter */
580         if (flags & IP_VS_CONN_F_SYNC) {
581                 /* if the connection is not template and is created
582                  * by sync, preserve the activity flag.
583                  */
584                 if (!(flags & IP_VS_CONN_F_TEMPLATE))
585                         conn_flags &= ~IP_VS_CONN_F_INACTIVE;
586                 /* connections inherit forwarding method from dest */
587                 flags &= ~(IP_VS_CONN_F_FWD_MASK | IP_VS_CONN_F_NOOUTPUT);
588         }
589         flags |= conn_flags;
590         cp->flags = flags;
591         cp->dest = dest;
592 
593         IP_VS_DBG_BUF(7, "Bind-dest %s c:%s:%d v:%s:%d "
594                       "d:%s:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
595                       "dest->refcnt:%d\n",
596                       ip_vs_proto_name(cp->protocol),
597                       IP_VS_DBG_ADDR(cp->af, &cp->caddr), ntohs(cp->cport),
598                       IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
599                       IP_VS_DBG_ADDR(cp->daf, &cp->daddr), ntohs(cp->dport),
600                       ip_vs_fwd_tag(cp), cp->state,
601                       cp->flags, atomic_read(&cp->refcnt),
602                       atomic_read(&dest->refcnt));
603 
604         /* Update the connection counters */
605         if (!(flags & IP_VS_CONN_F_TEMPLATE)) {
606                 /* It is a normal connection, so modify the counters
607                  * according to the flags, later the protocol can
608                  * update them on state change
609                  */
610                 if (!(flags & IP_VS_CONN_F_INACTIVE))
611                         atomic_inc(&dest->activeconns);
612                 else
613                         atomic_inc(&dest->inactconns);
614         } else {
615                 /* It is a persistent connection/template, so increase
616                    the persistent connection counter */
617                 atomic_inc(&dest->persistconns);
618         }
619 
620         if (dest->u_threshold != 0 &&
621             ip_vs_dest_totalconns(dest) >= dest->u_threshold)
622                 dest->flags |= IP_VS_DEST_F_OVERLOAD;
623 }
624 
625 
626 /*
627  * Check if there is a destination for the connection, if so
628  * bind the connection to the destination.
629  */
630 void ip_vs_try_bind_dest(struct ip_vs_conn *cp)
631 {
632         struct ip_vs_dest *dest;
633 
634         rcu_read_lock();
635 
636         /* This function is only invoked by the synchronization code. We do
637          * not currently support heterogeneous pools with synchronization,
638          * so we can make the assumption that the svc_af is the same as the
639          * dest_af
640          */
641         dest = ip_vs_find_dest(ip_vs_conn_net(cp), cp->af, cp->af, &cp->daddr,
642                                cp->dport, &cp->vaddr, cp->vport,
643                                cp->protocol, cp->fwmark, cp->flags);
644         if (dest) {
645                 struct ip_vs_proto_data *pd;
646 
647                 spin_lock_bh(&cp->lock);
648                 if (cp->dest) {
649                         spin_unlock_bh(&cp->lock);
650                         rcu_read_unlock();
651                         return;
652                 }
653 
654                 /* Applications work depending on the forwarding method
655                  * but better to reassign them always when binding dest */
656                 if (cp->app)
657                         ip_vs_unbind_app(cp);
658 
659                 ip_vs_bind_dest(cp, dest);
660                 spin_unlock_bh(&cp->lock);
661 
662                 /* Update its packet transmitter */
663                 cp->packet_xmit = NULL;
664 #ifdef CONFIG_IP_VS_IPV6
665                 if (cp->af == AF_INET6)
666                         ip_vs_bind_xmit_v6(cp);
667                 else
668 #endif
669                         ip_vs_bind_xmit(cp);
670 
671                 pd = ip_vs_proto_data_get(ip_vs_conn_net(cp), cp->protocol);
672                 if (pd && atomic_read(&pd->appcnt))
673                         ip_vs_bind_app(cp, pd->pp);
674         }
675         rcu_read_unlock();
676 }
677 
678 
679 /*
680  *      Unbind a connection entry with its VS destination
681  *      Called by the ip_vs_conn_expire function.
682  */
683 static inline void ip_vs_unbind_dest(struct ip_vs_conn *cp)
684 {
685         struct ip_vs_dest *dest = cp->dest;
686 
687         if (!dest)
688                 return;
689 
690         IP_VS_DBG_BUF(7, "Unbind-dest %s c:%s:%d v:%s:%d "
691                       "d:%s:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
692                       "dest->refcnt:%d\n",
693                       ip_vs_proto_name(cp->protocol),
694                       IP_VS_DBG_ADDR(cp->af, &cp->caddr), ntohs(cp->cport),
695                       IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
696                       IP_VS_DBG_ADDR(cp->daf, &cp->daddr), ntohs(cp->dport),
697                       ip_vs_fwd_tag(cp), cp->state,
698                       cp->flags, atomic_read(&cp->refcnt),
699                       atomic_read(&dest->refcnt));
700 
701         /* Update the connection counters */
702         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
703                 /* It is a normal connection, so decrease the inactconns
704                    or activeconns counter */
705                 if (cp->flags & IP_VS_CONN_F_INACTIVE) {
706                         atomic_dec(&dest->inactconns);
707                 } else {
708                         atomic_dec(&dest->activeconns);
709                 }
710         } else {
711                 /* It is a persistent connection/template, so decrease
712                    the persistent connection counter */
713                 atomic_dec(&dest->persistconns);
714         }
715 
716         if (dest->l_threshold != 0) {
717                 if (ip_vs_dest_totalconns(dest) < dest->l_threshold)
718                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
719         } else if (dest->u_threshold != 0) {
720                 if (ip_vs_dest_totalconns(dest) * 4 < dest->u_threshold * 3)
721                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
722         } else {
723                 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
724                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
725         }
726 
727         ip_vs_dest_put(dest);
728 }
729 
730 static int expire_quiescent_template(struct netns_ipvs *ipvs,
731                                      struct ip_vs_dest *dest)
732 {
733 #ifdef CONFIG_SYSCTL
734         return ipvs->sysctl_expire_quiescent_template &&
735                 (atomic_read(&dest->weight) == 0);
736 #else
737         return 0;
738 #endif
739 }
740 
741 /*
742  *      Checking if the destination of a connection template is available.
743  *      If available, return 1, otherwise invalidate this connection
744  *      template and return 0.
745  */
746 int ip_vs_check_template(struct ip_vs_conn *ct)
747 {
748         struct ip_vs_dest *dest = ct->dest;
749         struct netns_ipvs *ipvs = net_ipvs(ip_vs_conn_net(ct));
750 
751         /*
752          * Checking the dest server status.
753          */
754         if ((dest == NULL) ||
755             !(dest->flags & IP_VS_DEST_F_AVAILABLE) ||
756             expire_quiescent_template(ipvs, dest)) {
757                 IP_VS_DBG_BUF(9, "check_template: dest not available for "
758                               "protocol %s s:%s:%d v:%s:%d "
759                               "-> d:%s:%d\n",
760                               ip_vs_proto_name(ct->protocol),
761                               IP_VS_DBG_ADDR(ct->af, &ct->caddr),
762                               ntohs(ct->cport),
763                               IP_VS_DBG_ADDR(ct->af, &ct->vaddr),
764                               ntohs(ct->vport),
765                               IP_VS_DBG_ADDR(ct->daf, &ct->daddr),
766                               ntohs(ct->dport));
767 
768                 /*
769                  * Invalidate the connection template
770                  */
771                 if (ct->vport != htons(0xffff)) {
772                         if (ip_vs_conn_unhash(ct)) {
773                                 ct->dport = htons(0xffff);
774                                 ct->vport = htons(0xffff);
775                                 ct->cport = 0;
776                                 ip_vs_conn_hash(ct);
777                         }
778                 }
779 
780                 /*
781                  * Simply decrease the refcnt of the template,
782                  * don't restart its timer.
783                  */
784                 __ip_vs_conn_put(ct);
785                 return 0;
786         }
787         return 1;
788 }
789 
790 static void ip_vs_conn_rcu_free(struct rcu_head *head)
791 {
792         struct ip_vs_conn *cp = container_of(head, struct ip_vs_conn,
793                                              rcu_head);
794 
795         ip_vs_pe_put(cp->pe);
796         kfree(cp->pe_data);
797         kmem_cache_free(ip_vs_conn_cachep, cp);
798 }
799 
800 static void ip_vs_conn_expire(unsigned long data)
801 {
802         struct ip_vs_conn *cp = (struct ip_vs_conn *)data;
803         struct net *net = ip_vs_conn_net(cp);
804         struct netns_ipvs *ipvs = net_ipvs(net);
805 
806         /*
807          *      do I control anybody?
808          */
809         if (atomic_read(&cp->n_control))
810                 goto expire_later;
811 
812         /* Unlink conn if not referenced anymore */
813         if (likely(ip_vs_conn_unlink(cp))) {
814                 /* delete the timer if it is activated by other users */
815                 del_timer(&cp->timer);
816 
817                 /* does anybody control me? */
818                 if (cp->control)
819                         ip_vs_control_del(cp);
820 
821                 if (cp->flags & IP_VS_CONN_F_NFCT) {
822                         /* Do not access conntracks during subsys cleanup
823                          * because nf_conntrack_find_get can not be used after
824                          * conntrack cleanup for the net.
825                          */
826                         smp_rmb();
827                         if (ipvs->enable)
828                                 ip_vs_conn_drop_conntrack(cp);
829                 }
830 
831                 if (unlikely(cp->app != NULL))
832                         ip_vs_unbind_app(cp);
833                 ip_vs_unbind_dest(cp);
834                 if (cp->flags & IP_VS_CONN_F_NO_CPORT)
835                         atomic_dec(&ip_vs_conn_no_cport_cnt);
836                 call_rcu(&cp->rcu_head, ip_vs_conn_rcu_free);
837                 atomic_dec(&ipvs->conn_count);
838                 return;
839         }
840 
841   expire_later:
842         IP_VS_DBG(7, "delayed: conn->refcnt=%d conn->n_control=%d\n",
843                   atomic_read(&cp->refcnt),
844                   atomic_read(&cp->n_control));
845 
846         atomic_inc(&cp->refcnt);
847         cp->timeout = 60*HZ;
848 
849         if (ipvs->sync_state & IP_VS_STATE_MASTER)
850                 ip_vs_sync_conn(net, cp, sysctl_sync_threshold(ipvs));
851 
852         ip_vs_conn_put(cp);
853 }
854 
855 /* Modify timer, so that it expires as soon as possible.
856  * Can be called without reference only if under RCU lock.
857  */
858 void ip_vs_conn_expire_now(struct ip_vs_conn *cp)
859 {
860         /* Using mod_timer_pending will ensure the timer is not
861          * modified after the final del_timer in ip_vs_conn_expire.
862          */
863         if (timer_pending(&cp->timer) &&
864             time_after(cp->timer.expires, jiffies))
865                 mod_timer_pending(&cp->timer, jiffies);
866 }
867 
868 
869 /*
870  *      Create a new connection entry and hash it into the ip_vs_conn_tab
871  */
872 struct ip_vs_conn *
873 ip_vs_conn_new(const struct ip_vs_conn_param *p, int dest_af,
874                const union nf_inet_addr *daddr, __be16 dport, unsigned int flags,
875                struct ip_vs_dest *dest, __u32 fwmark)
876 {
877         struct ip_vs_conn *cp;
878         struct netns_ipvs *ipvs = net_ipvs(p->net);
879         struct ip_vs_proto_data *pd = ip_vs_proto_data_get(p->net,
880                                                            p->protocol);
881 
882         cp = kmem_cache_alloc(ip_vs_conn_cachep, GFP_ATOMIC);
883         if (cp == NULL) {
884                 IP_VS_ERR_RL("%s(): no memory\n", __func__);
885                 return NULL;
886         }
887 
888         INIT_HLIST_NODE(&cp->c_list);
889         setup_timer(&cp->timer, ip_vs_conn_expire, (unsigned long)cp);
890         ip_vs_conn_net_set(cp, p->net);
891         cp->af             = p->af;
892         cp->daf            = dest_af;
893         cp->protocol       = p->protocol;
894         ip_vs_addr_set(p->af, &cp->caddr, p->caddr);
895         cp->cport          = p->cport;
896         /* proto should only be IPPROTO_IP if p->vaddr is a fwmark */
897         ip_vs_addr_set(p->protocol == IPPROTO_IP ? AF_UNSPEC : p->af,
898                        &cp->vaddr, p->vaddr);
899         cp->vport          = p->vport;
900         ip_vs_addr_set(cp->daf, &cp->daddr, daddr);
901         cp->dport          = dport;
902         cp->flags          = flags;
903         cp->fwmark         = fwmark;
904         if (flags & IP_VS_CONN_F_TEMPLATE && p->pe) {
905                 ip_vs_pe_get(p->pe);
906                 cp->pe = p->pe;
907                 cp->pe_data = p->pe_data;
908                 cp->pe_data_len = p->pe_data_len;
909         } else {
910                 cp->pe = NULL;
911                 cp->pe_data = NULL;
912                 cp->pe_data_len = 0;
913         }
914         spin_lock_init(&cp->lock);
915 
916         /*
917          * Set the entry is referenced by the current thread before hashing
918          * it in the table, so that other thread run ip_vs_random_dropentry
919          * but cannot drop this entry.
920          */
921         atomic_set(&cp->refcnt, 1);
922 
923         cp->control = NULL;
924         atomic_set(&cp->n_control, 0);
925         atomic_set(&cp->in_pkts, 0);
926 
927         cp->packet_xmit = NULL;
928         cp->app = NULL;
929         cp->app_data = NULL;
930         /* reset struct ip_vs_seq */
931         cp->in_seq.delta = 0;
932         cp->out_seq.delta = 0;
933 
934         atomic_inc(&ipvs->conn_count);
935         if (flags & IP_VS_CONN_F_NO_CPORT)
936                 atomic_inc(&ip_vs_conn_no_cport_cnt);
937 
938         /* Bind the connection with a destination server */
939         cp->dest = NULL;
940         ip_vs_bind_dest(cp, dest);
941 
942         /* Set its state and timeout */
943         cp->state = 0;
944         cp->old_state = 0;
945         cp->timeout = 3*HZ;
946         cp->sync_endtime = jiffies & ~3UL;
947 
948         /* Bind its packet transmitter */
949 #ifdef CONFIG_IP_VS_IPV6
950         if (p->af == AF_INET6)
951                 ip_vs_bind_xmit_v6(cp);
952         else
953 #endif
954                 ip_vs_bind_xmit(cp);
955 
956         if (unlikely(pd && atomic_read(&pd->appcnt)))
957                 ip_vs_bind_app(cp, pd->pp);
958 
959         /*
960          * Allow conntrack to be preserved. By default, conntrack
961          * is created and destroyed for every packet.
962          * Sometimes keeping conntrack can be useful for
963          * IP_VS_CONN_F_ONE_PACKET too.
964          */
965 
966         if (ip_vs_conntrack_enabled(ipvs))
967                 cp->flags |= IP_VS_CONN_F_NFCT;
968 
969         /* Hash it in the ip_vs_conn_tab finally */
970         ip_vs_conn_hash(cp);
971 
972         return cp;
973 }
974 
975 /*
976  *      /proc/net/ip_vs_conn entries
977  */
978 #ifdef CONFIG_PROC_FS
979 struct ip_vs_iter_state {
980         struct seq_net_private  p;
981         struct hlist_head       *l;
982 };
983 
984 static void *ip_vs_conn_array(struct seq_file *seq, loff_t pos)
985 {
986         int idx;
987         struct ip_vs_conn *cp;
988         struct ip_vs_iter_state *iter = seq->private;
989 
990         for (idx = 0; idx < ip_vs_conn_tab_size; idx++) {
991                 hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[idx], c_list) {
992                         /* __ip_vs_conn_get() is not needed by
993                          * ip_vs_conn_seq_show and ip_vs_conn_sync_seq_show
994                          */
995                         if (pos-- == 0) {
996                                 iter->l = &ip_vs_conn_tab[idx];
997                                 return cp;
998                         }
999                 }
1000                 cond_resched_rcu();
1001         }
1002 
1003         return NULL;
1004 }
1005 
1006 static void *ip_vs_conn_seq_start(struct seq_file *seq, loff_t *pos)
1007         __acquires(RCU)
1008 {
1009         struct ip_vs_iter_state *iter = seq->private;
1010 
1011         iter->l = NULL;
1012         rcu_read_lock();
1013         return *pos ? ip_vs_conn_array(seq, *pos - 1) :SEQ_START_TOKEN;
1014 }
1015 
1016 static void *ip_vs_conn_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1017 {
1018         struct ip_vs_conn *cp = v;
1019         struct ip_vs_iter_state *iter = seq->private;
1020         struct hlist_node *e;
1021         struct hlist_head *l = iter->l;
1022         int idx;
1023 
1024         ++*pos;
1025         if (v == SEQ_START_TOKEN)
1026                 return ip_vs_conn_array(seq, 0);
1027 
1028         /* more on same hash chain? */
1029         e = rcu_dereference(hlist_next_rcu(&cp->c_list));
1030         if (e)
1031                 return hlist_entry(e, struct ip_vs_conn, c_list);
1032 
1033         idx = l - ip_vs_conn_tab;
1034         while (++idx < ip_vs_conn_tab_size) {
1035                 hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[idx], c_list) {
1036                         iter->l = &ip_vs_conn_tab[idx];
1037                         return cp;
1038                 }
1039                 cond_resched_rcu();
1040         }
1041         iter->l = NULL;
1042         return NULL;
1043 }
1044 
1045 static void ip_vs_conn_seq_stop(struct seq_file *seq, void *v)
1046         __releases(RCU)
1047 {
1048         rcu_read_unlock();
1049 }
1050 
1051 static int ip_vs_conn_seq_show(struct seq_file *seq, void *v)
1052 {
1053 
1054         if (v == SEQ_START_TOKEN)
1055                 seq_puts(seq,
1056    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Expires PEName PEData\n");
1057         else {
1058                 const struct ip_vs_conn *cp = v;
1059                 struct net *net = seq_file_net(seq);
1060                 char pe_data[IP_VS_PENAME_MAXLEN + IP_VS_PEDATA_MAXLEN + 3];
1061                 size_t len = 0;
1062                 char dbuf[IP_VS_ADDRSTRLEN];
1063 
1064                 if (!ip_vs_conn_net_eq(cp, net))
1065                         return 0;
1066                 if (cp->pe_data) {
1067                         pe_data[0] = ' ';
1068                         len = strlen(cp->pe->name);
1069                         memcpy(pe_data + 1, cp->pe->name, len);
1070                         pe_data[len + 1] = ' ';
1071                         len += 2;
1072                         len += cp->pe->show_pe_data(cp, pe_data + len);
1073                 }
1074                 pe_data[len] = '\0';
1075 
1076 #ifdef CONFIG_IP_VS_IPV6
1077                 if (cp->daf == AF_INET6)
1078                         snprintf(dbuf, sizeof(dbuf), "%pI6", &cp->daddr.in6);
1079                 else
1080 #endif
1081                         snprintf(dbuf, sizeof(dbuf), "%08X",
1082                                  ntohl(cp->daddr.ip));
1083 
1084 #ifdef CONFIG_IP_VS_IPV6
1085                 if (cp->af == AF_INET6)
1086                         seq_printf(seq, "%-3s %pI6 %04X %pI6 %04X "
1087                                 "%s %04X %-11s %7lu%s\n",
1088                                 ip_vs_proto_name(cp->protocol),
1089                                 &cp->caddr.in6, ntohs(cp->cport),
1090                                 &cp->vaddr.in6, ntohs(cp->vport),
1091                                 dbuf, ntohs(cp->dport),
1092                                 ip_vs_state_name(cp->protocol, cp->state),
1093                                 (cp->timer.expires-jiffies)/HZ, pe_data);
1094                 else
1095 #endif
1096                         seq_printf(seq,
1097                                 "%-3s %08X %04X %08X %04X"
1098                                 " %s %04X %-11s %7lu%s\n",
1099                                 ip_vs_proto_name(cp->protocol),
1100                                 ntohl(cp->caddr.ip), ntohs(cp->cport),
1101                                 ntohl(cp->vaddr.ip), ntohs(cp->vport),
1102                                 dbuf, ntohs(cp->dport),
1103                                 ip_vs_state_name(cp->protocol, cp->state),
1104                                 (cp->timer.expires-jiffies)/HZ, pe_data);
1105         }
1106         return 0;
1107 }
1108 
1109 static const struct seq_operations ip_vs_conn_seq_ops = {
1110         .start = ip_vs_conn_seq_start,
1111         .next  = ip_vs_conn_seq_next,
1112         .stop  = ip_vs_conn_seq_stop,
1113         .show  = ip_vs_conn_seq_show,
1114 };
1115 
1116 static int ip_vs_conn_open(struct inode *inode, struct file *file)
1117 {
1118         return seq_open_net(inode, file, &ip_vs_conn_seq_ops,
1119                             sizeof(struct ip_vs_iter_state));
1120 }
1121 
1122 static const struct file_operations ip_vs_conn_fops = {
1123         .owner   = THIS_MODULE,
1124         .open    = ip_vs_conn_open,
1125         .read    = seq_read,
1126         .llseek  = seq_lseek,
1127         .release = seq_release_net,
1128 };
1129 
1130 static const char *ip_vs_origin_name(unsigned int flags)
1131 {
1132         if (flags & IP_VS_CONN_F_SYNC)
1133                 return "SYNC";
1134         else
1135                 return "LOCAL";
1136 }
1137 
1138 static int ip_vs_conn_sync_seq_show(struct seq_file *seq, void *v)
1139 {
1140         char dbuf[IP_VS_ADDRSTRLEN];
1141 
1142         if (v == SEQ_START_TOKEN)
1143                 seq_puts(seq,
1144    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Origin Expires\n");
1145         else {
1146                 const struct ip_vs_conn *cp = v;
1147                 struct net *net = seq_file_net(seq);
1148 
1149                 if (!ip_vs_conn_net_eq(cp, net))
1150                         return 0;
1151 
1152 #ifdef CONFIG_IP_VS_IPV6
1153                 if (cp->daf == AF_INET6)
1154                         snprintf(dbuf, sizeof(dbuf), "%pI6", &cp->daddr.in6);
1155                 else
1156 #endif
1157                         snprintf(dbuf, sizeof(dbuf), "%08X",
1158                                  ntohl(cp->daddr.ip));
1159 
1160 #ifdef CONFIG_IP_VS_IPV6
1161                 if (cp->af == AF_INET6)
1162                         seq_printf(seq, "%-3s %pI6 %04X %pI6 %04X "
1163                                 "%s %04X %-11s %-6s %7lu\n",
1164                                 ip_vs_proto_name(cp->protocol),
1165                                 &cp->caddr.in6, ntohs(cp->cport),
1166                                 &cp->vaddr.in6, ntohs(cp->vport),
1167                                 dbuf, ntohs(cp->dport),
1168                                 ip_vs_state_name(cp->protocol, cp->state),
1169                                 ip_vs_origin_name(cp->flags),
1170                                 (cp->timer.expires-jiffies)/HZ);
1171                 else
1172 #endif
1173                         seq_printf(seq,
1174                                 "%-3s %08X %04X %08X %04X "
1175                                 "%s %04X %-11s %-6s %7lu\n",
1176                                 ip_vs_proto_name(cp->protocol),
1177                                 ntohl(cp->caddr.ip), ntohs(cp->cport),
1178                                 ntohl(cp->vaddr.ip), ntohs(cp->vport),
1179                                 dbuf, ntohs(cp->dport),
1180                                 ip_vs_state_name(cp->protocol, cp->state),
1181                                 ip_vs_origin_name(cp->flags),
1182                                 (cp->timer.expires-jiffies)/HZ);
1183         }
1184         return 0;
1185 }
1186 
1187 static const struct seq_operations ip_vs_conn_sync_seq_ops = {
1188         .start = ip_vs_conn_seq_start,
1189         .next  = ip_vs_conn_seq_next,
1190         .stop  = ip_vs_conn_seq_stop,
1191         .show  = ip_vs_conn_sync_seq_show,
1192 };
1193 
1194 static int ip_vs_conn_sync_open(struct inode *inode, struct file *file)
1195 {
1196         return seq_open_net(inode, file, &ip_vs_conn_sync_seq_ops,
1197                             sizeof(struct ip_vs_iter_state));
1198 }
1199 
1200 static const struct file_operations ip_vs_conn_sync_fops = {
1201         .owner   = THIS_MODULE,
1202         .open    = ip_vs_conn_sync_open,
1203         .read    = seq_read,
1204         .llseek  = seq_lseek,
1205         .release = seq_release_net,
1206 };
1207 
1208 #endif
1209 
1210 
1211 /*
1212  *      Randomly drop connection entries before running out of memory
1213  */
1214 static inline int todrop_entry(struct ip_vs_conn *cp)
1215 {
1216         /*
1217          * The drop rate array needs tuning for real environments.
1218          * Called from timer bh only => no locking
1219          */
1220         static const char todrop_rate[9] = {0, 1, 2, 3, 4, 5, 6, 7, 8};
1221         static char todrop_counter[9] = {0};
1222         int i;
1223 
1224         /* if the conn entry hasn't lasted for 60 seconds, don't drop it.
1225            This will leave enough time for normal connection to get
1226            through. */
1227         if (time_before(cp->timeout + jiffies, cp->timer.expires + 60*HZ))
1228                 return 0;
1229 
1230         /* Don't drop the entry if its number of incoming packets is not
1231            located in [0, 8] */
1232         i = atomic_read(&cp->in_pkts);
1233         if (i > 8 || i < 0) return 0;
1234 
1235         if (!todrop_rate[i]) return 0;
1236         if (--todrop_counter[i] > 0) return 0;
1237 
1238         todrop_counter[i] = todrop_rate[i];
1239         return 1;
1240 }
1241 
1242 /* Called from keventd and must protect itself from softirqs */
1243 void ip_vs_random_dropentry(struct net *net)
1244 {
1245         int idx;
1246         struct ip_vs_conn *cp, *cp_c;
1247 
1248         rcu_read_lock();
1249         /*
1250          * Randomly scan 1/32 of the whole table every second
1251          */
1252         for (idx = 0; idx < (ip_vs_conn_tab_size>>5); idx++) {
1253                 unsigned int hash = prandom_u32() & ip_vs_conn_tab_mask;
1254 
1255                 hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[hash], c_list) {
1256                         if (cp->flags & IP_VS_CONN_F_TEMPLATE)
1257                                 /* connection template */
1258                                 continue;
1259                         if (!ip_vs_conn_net_eq(cp, net))
1260                                 continue;
1261                         if (cp->protocol == IPPROTO_TCP) {
1262                                 switch(cp->state) {
1263                                 case IP_VS_TCP_S_SYN_RECV:
1264                                 case IP_VS_TCP_S_SYNACK:
1265                                         break;
1266 
1267                                 case IP_VS_TCP_S_ESTABLISHED:
1268                                         if (todrop_entry(cp))
1269                                                 break;
1270                                         continue;
1271 
1272                                 default:
1273                                         continue;
1274                                 }
1275                         } else if (cp->protocol == IPPROTO_SCTP) {
1276                                 switch (cp->state) {
1277                                 case IP_VS_SCTP_S_INIT1:
1278                                 case IP_VS_SCTP_S_INIT:
1279                                         break;
1280                                 case IP_VS_SCTP_S_ESTABLISHED:
1281                                         if (todrop_entry(cp))
1282                                                 break;
1283                                         continue;
1284                                 default:
1285                                         continue;
1286                                 }
1287                         } else {
1288                                 if (!todrop_entry(cp))
1289                                         continue;
1290                         }
1291 
1292                         IP_VS_DBG(4, "del connection\n");
1293                         ip_vs_conn_expire_now(cp);
1294                         cp_c = cp->control;
1295                         /* cp->control is valid only with reference to cp */
1296                         if (cp_c && __ip_vs_conn_get(cp)) {
1297                                 IP_VS_DBG(4, "del conn template\n");
1298                                 ip_vs_conn_expire_now(cp_c);
1299                                 __ip_vs_conn_put(cp);
1300                         }
1301                 }
1302                 cond_resched_rcu();
1303         }
1304         rcu_read_unlock();
1305 }
1306 
1307 
1308 /*
1309  *      Flush all the connection entries in the ip_vs_conn_tab
1310  */
1311 static void ip_vs_conn_flush(struct net *net)
1312 {
1313         int idx;
1314         struct ip_vs_conn *cp, *cp_c;
1315         struct netns_ipvs *ipvs = net_ipvs(net);
1316 
1317 flush_again:
1318         rcu_read_lock();
1319         for (idx = 0; idx < ip_vs_conn_tab_size; idx++) {
1320 
1321                 hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[idx], c_list) {
1322                         if (!ip_vs_conn_net_eq(cp, net))
1323                                 continue;
1324                         IP_VS_DBG(4, "del connection\n");
1325                         ip_vs_conn_expire_now(cp);
1326                         cp_c = cp->control;
1327                         /* cp->control is valid only with reference to cp */
1328                         if (cp_c && __ip_vs_conn_get(cp)) {
1329                                 IP_VS_DBG(4, "del conn template\n");
1330                                 ip_vs_conn_expire_now(cp_c);
1331                                 __ip_vs_conn_put(cp);
1332                         }
1333                 }
1334                 cond_resched_rcu();
1335         }
1336         rcu_read_unlock();
1337 
1338         /* the counter may be not NULL, because maybe some conn entries
1339            are run by slow timer handler or unhashed but still referred */
1340         if (atomic_read(&ipvs->conn_count) != 0) {
1341                 schedule();
1342                 goto flush_again;
1343         }
1344 }
1345 /*
1346  * per netns init and exit
1347  */
1348 int __net_init ip_vs_conn_net_init(struct net *net)
1349 {
1350         struct netns_ipvs *ipvs = net_ipvs(net);
1351 
1352         atomic_set(&ipvs->conn_count, 0);
1353 
1354         proc_create("ip_vs_conn", 0, net->proc_net, &ip_vs_conn_fops);
1355         proc_create("ip_vs_conn_sync", 0, net->proc_net, &ip_vs_conn_sync_fops);
1356         return 0;
1357 }
1358 
1359 void __net_exit ip_vs_conn_net_cleanup(struct net *net)
1360 {
1361         /* flush all the connection entries first */
1362         ip_vs_conn_flush(net);
1363         remove_proc_entry("ip_vs_conn", net->proc_net);
1364         remove_proc_entry("ip_vs_conn_sync", net->proc_net);
1365 }
1366 
1367 int __init ip_vs_conn_init(void)
1368 {
1369         int idx;
1370 
1371         /* Compute size and mask */
1372         ip_vs_conn_tab_size = 1 << ip_vs_conn_tab_bits;
1373         ip_vs_conn_tab_mask = ip_vs_conn_tab_size - 1;
1374 
1375         /*
1376          * Allocate the connection hash table and initialize its list heads
1377          */
1378         ip_vs_conn_tab = vmalloc(ip_vs_conn_tab_size * sizeof(*ip_vs_conn_tab));
1379         if (!ip_vs_conn_tab)
1380                 return -ENOMEM;
1381 
1382         /* Allocate ip_vs_conn slab cache */
1383         ip_vs_conn_cachep = kmem_cache_create("ip_vs_conn",
1384                                               sizeof(struct ip_vs_conn), 0,
1385                                               SLAB_HWCACHE_ALIGN, NULL);
1386         if (!ip_vs_conn_cachep) {
1387                 vfree(ip_vs_conn_tab);
1388                 return -ENOMEM;
1389         }
1390 
1391         pr_info("Connection hash table configured "
1392                 "(size=%d, memory=%ldKbytes)\n",
1393                 ip_vs_conn_tab_size,
1394                 (long)(ip_vs_conn_tab_size*sizeof(struct list_head))/1024);
1395         IP_VS_DBG(0, "Each connection entry needs %Zd bytes at least\n",
1396                   sizeof(struct ip_vs_conn));
1397 
1398         for (idx = 0; idx < ip_vs_conn_tab_size; idx++)
1399                 INIT_HLIST_HEAD(&ip_vs_conn_tab[idx]);
1400 
1401         for (idx = 0; idx < CT_LOCKARRAY_SIZE; idx++)  {
1402                 spin_lock_init(&__ip_vs_conntbl_lock_array[idx].l);
1403         }
1404 
1405         /* calculate the random value for connection hash */
1406         get_random_bytes(&ip_vs_conn_rnd, sizeof(ip_vs_conn_rnd));
1407 
1408         return 0;
1409 }
1410 
1411 void ip_vs_conn_cleanup(void)
1412 {
1413         /* Wait all ip_vs_conn_rcu_free() callbacks to complete */
1414         rcu_barrier();
1415         /* Release the empty cache */
1416         kmem_cache_destroy(ip_vs_conn_cachep);
1417         vfree(ip_vs_conn_tab);
1418 }
1419 

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