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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 static void ip_vs_conn_expire(struct timer_list *t);
108 
109 /*
110  *      Returns hash value for IPVS connection entry
111  */
112 static unsigned int ip_vs_conn_hashkey(struct netns_ipvs *ipvs, int af, unsigned int proto,
113                                        const union nf_inet_addr *addr,
114                                        __be16 port)
115 {
116 #ifdef CONFIG_IP_VS_IPV6
117         if (af == AF_INET6)
118                 return (jhash_3words(jhash(addr, 16, ip_vs_conn_rnd),
119                                     (__force u32)port, proto, ip_vs_conn_rnd) ^
120                         ((size_t)ipvs>>8)) & ip_vs_conn_tab_mask;
121 #endif
122         return (jhash_3words((__force u32)addr->ip, (__force u32)port, proto,
123                             ip_vs_conn_rnd) ^
124                 ((size_t)ipvs>>8)) & ip_vs_conn_tab_mask;
125 }
126 
127 static unsigned int ip_vs_conn_hashkey_param(const struct ip_vs_conn_param *p,
128                                              bool inverse)
129 {
130         const union nf_inet_addr *addr;
131         __be16 port;
132 
133         if (p->pe_data && p->pe->hashkey_raw)
134                 return p->pe->hashkey_raw(p, ip_vs_conn_rnd, inverse) &
135                         ip_vs_conn_tab_mask;
136 
137         if (likely(!inverse)) {
138                 addr = p->caddr;
139                 port = p->cport;
140         } else {
141                 addr = p->vaddr;
142                 port = p->vport;
143         }
144 
145         return ip_vs_conn_hashkey(p->ipvs, p->af, p->protocol, addr, port);
146 }
147 
148 static unsigned int ip_vs_conn_hashkey_conn(const struct ip_vs_conn *cp)
149 {
150         struct ip_vs_conn_param p;
151 
152         ip_vs_conn_fill_param(cp->ipvs, cp->af, cp->protocol,
153                               &cp->caddr, cp->cport, NULL, 0, &p);
154 
155         if (cp->pe) {
156                 p.pe = cp->pe;
157                 p.pe_data = cp->pe_data;
158                 p.pe_data_len = cp->pe_data_len;
159         }
160 
161         return ip_vs_conn_hashkey_param(&p, false);
162 }
163 
164 /*
165  *      Hashes ip_vs_conn in ip_vs_conn_tab by netns,proto,addr,port.
166  *      returns bool success.
167  */
168 static inline int ip_vs_conn_hash(struct ip_vs_conn *cp)
169 {
170         unsigned int hash;
171         int ret;
172 
173         if (cp->flags & IP_VS_CONN_F_ONE_PACKET)
174                 return 0;
175 
176         /* Hash by protocol, client address and port */
177         hash = ip_vs_conn_hashkey_conn(cp);
178 
179         ct_write_lock_bh(hash);
180         spin_lock(&cp->lock);
181 
182         if (!(cp->flags & IP_VS_CONN_F_HASHED)) {
183                 cp->flags |= IP_VS_CONN_F_HASHED;
184                 refcount_inc(&cp->refcnt);
185                 hlist_add_head_rcu(&cp->c_list, &ip_vs_conn_tab[hash]);
186                 ret = 1;
187         } else {
188                 pr_err("%s(): request for already hashed, called from %pS\n",
189                        __func__, __builtin_return_address(0));
190                 ret = 0;
191         }
192 
193         spin_unlock(&cp->lock);
194         ct_write_unlock_bh(hash);
195 
196         return ret;
197 }
198 
199 
200 /*
201  *      UNhashes ip_vs_conn from ip_vs_conn_tab.
202  *      returns bool success. Caller should hold conn reference.
203  */
204 static inline int ip_vs_conn_unhash(struct ip_vs_conn *cp)
205 {
206         unsigned int hash;
207         int ret;
208 
209         /* unhash it and decrease its reference counter */
210         hash = ip_vs_conn_hashkey_conn(cp);
211 
212         ct_write_lock_bh(hash);
213         spin_lock(&cp->lock);
214 
215         if (cp->flags & IP_VS_CONN_F_HASHED) {
216                 hlist_del_rcu(&cp->c_list);
217                 cp->flags &= ~IP_VS_CONN_F_HASHED;
218                 refcount_dec(&cp->refcnt);
219                 ret = 1;
220         } else
221                 ret = 0;
222 
223         spin_unlock(&cp->lock);
224         ct_write_unlock_bh(hash);
225 
226         return ret;
227 }
228 
229 /* Try to unlink ip_vs_conn from ip_vs_conn_tab.
230  * returns bool success.
231  */
232 static inline bool ip_vs_conn_unlink(struct ip_vs_conn *cp)
233 {
234         unsigned int hash;
235         bool ret = false;
236 
237         if (cp->flags & IP_VS_CONN_F_ONE_PACKET)
238                 return refcount_dec_if_one(&cp->refcnt);
239 
240         hash = ip_vs_conn_hashkey_conn(cp);
241 
242         ct_write_lock_bh(hash);
243         spin_lock(&cp->lock);
244 
245         if (cp->flags & IP_VS_CONN_F_HASHED) {
246                 /* Decrease refcnt and unlink conn only if we are last user */
247                 if (refcount_dec_if_one(&cp->refcnt)) {
248                         hlist_del_rcu(&cp->c_list);
249                         cp->flags &= ~IP_VS_CONN_F_HASHED;
250                         ret = true;
251                 }
252         }
253 
254         spin_unlock(&cp->lock);
255         ct_write_unlock_bh(hash);
256 
257         return ret;
258 }
259 
260 
261 /*
262  *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
263  *  Called for pkts coming from OUTside-to-INside.
264  *      p->caddr, p->cport: pkt source address (foreign host)
265  *      p->vaddr, p->vport: pkt dest address (load balancer)
266  */
267 static inline struct ip_vs_conn *
268 __ip_vs_conn_in_get(const struct ip_vs_conn_param *p)
269 {
270         unsigned int hash;
271         struct ip_vs_conn *cp;
272 
273         hash = ip_vs_conn_hashkey_param(p, false);
274 
275         rcu_read_lock();
276 
277         hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[hash], c_list) {
278                 if (p->cport == cp->cport && p->vport == cp->vport &&
279                     cp->af == p->af &&
280                     ip_vs_addr_equal(p->af, p->caddr, &cp->caddr) &&
281                     ip_vs_addr_equal(p->af, p->vaddr, &cp->vaddr) &&
282                     ((!p->cport) ^ (!(cp->flags & IP_VS_CONN_F_NO_CPORT))) &&
283                     p->protocol == cp->protocol &&
284                     cp->ipvs == p->ipvs) {
285                         if (!__ip_vs_conn_get(cp))
286                                 continue;
287                         /* HIT */
288                         rcu_read_unlock();
289                         return cp;
290                 }
291         }
292 
293         rcu_read_unlock();
294 
295         return NULL;
296 }
297 
298 struct ip_vs_conn *ip_vs_conn_in_get(const struct ip_vs_conn_param *p)
299 {
300         struct ip_vs_conn *cp;
301 
302         cp = __ip_vs_conn_in_get(p);
303         if (!cp && atomic_read(&ip_vs_conn_no_cport_cnt)) {
304                 struct ip_vs_conn_param cport_zero_p = *p;
305                 cport_zero_p.cport = 0;
306                 cp = __ip_vs_conn_in_get(&cport_zero_p);
307         }
308 
309         IP_VS_DBG_BUF(9, "lookup/in %s %s:%d->%s:%d %s\n",
310                       ip_vs_proto_name(p->protocol),
311                       IP_VS_DBG_ADDR(p->af, p->caddr), ntohs(p->cport),
312                       IP_VS_DBG_ADDR(p->af, p->vaddr), ntohs(p->vport),
313                       cp ? "hit" : "not hit");
314 
315         return cp;
316 }
317 
318 static int
319 ip_vs_conn_fill_param_proto(struct netns_ipvs *ipvs,
320                             int af, const struct sk_buff *skb,
321                             const struct ip_vs_iphdr *iph,
322                             struct ip_vs_conn_param *p)
323 {
324         __be16 _ports[2], *pptr;
325 
326         pptr = frag_safe_skb_hp(skb, iph->len, sizeof(_ports), _ports);
327         if (pptr == NULL)
328                 return 1;
329 
330         if (likely(!ip_vs_iph_inverse(iph)))
331                 ip_vs_conn_fill_param(ipvs, af, iph->protocol, &iph->saddr,
332                                       pptr[0], &iph->daddr, pptr[1], p);
333         else
334                 ip_vs_conn_fill_param(ipvs, af, iph->protocol, &iph->daddr,
335                                       pptr[1], &iph->saddr, pptr[0], p);
336         return 0;
337 }
338 
339 struct ip_vs_conn *
340 ip_vs_conn_in_get_proto(struct netns_ipvs *ipvs, int af,
341                         const struct sk_buff *skb,
342                         const struct ip_vs_iphdr *iph)
343 {
344         struct ip_vs_conn_param p;
345 
346         if (ip_vs_conn_fill_param_proto(ipvs, af, skb, iph, &p))
347                 return NULL;
348 
349         return ip_vs_conn_in_get(&p);
350 }
351 EXPORT_SYMBOL_GPL(ip_vs_conn_in_get_proto);
352 
353 /* Get reference to connection template */
354 struct ip_vs_conn *ip_vs_ct_in_get(const struct ip_vs_conn_param *p)
355 {
356         unsigned int hash;
357         struct ip_vs_conn *cp;
358 
359         hash = ip_vs_conn_hashkey_param(p, false);
360 
361         rcu_read_lock();
362 
363         hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[hash], c_list) {
364                 if (unlikely(p->pe_data && p->pe->ct_match)) {
365                         if (cp->ipvs != p->ipvs)
366                                 continue;
367                         if (p->pe == cp->pe && p->pe->ct_match(p, cp)) {
368                                 if (__ip_vs_conn_get(cp))
369                                         goto out;
370                         }
371                         continue;
372                 }
373 
374                 if (cp->af == p->af &&
375                     ip_vs_addr_equal(p->af, p->caddr, &cp->caddr) &&
376                     /* protocol should only be IPPROTO_IP if
377                      * p->vaddr is a fwmark */
378                     ip_vs_addr_equal(p->protocol == IPPROTO_IP ? AF_UNSPEC :
379                                      p->af, p->vaddr, &cp->vaddr) &&
380                     p->vport == cp->vport && p->cport == cp->cport &&
381                     cp->flags & IP_VS_CONN_F_TEMPLATE &&
382                     p->protocol == cp->protocol &&
383                     cp->ipvs == p->ipvs) {
384                         if (__ip_vs_conn_get(cp))
385                                 goto out;
386                 }
387         }
388         cp = NULL;
389 
390   out:
391         rcu_read_unlock();
392 
393         IP_VS_DBG_BUF(9, "template lookup/in %s %s:%d->%s:%d %s\n",
394                       ip_vs_proto_name(p->protocol),
395                       IP_VS_DBG_ADDR(p->af, p->caddr), ntohs(p->cport),
396                       IP_VS_DBG_ADDR(p->af, p->vaddr), ntohs(p->vport),
397                       cp ? "hit" : "not hit");
398 
399         return cp;
400 }
401 
402 /* Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
403  * Called for pkts coming from inside-to-OUTside.
404  *      p->caddr, p->cport: pkt source address (inside host)
405  *      p->vaddr, p->vport: pkt dest address (foreign host) */
406 struct ip_vs_conn *ip_vs_conn_out_get(const struct ip_vs_conn_param *p)
407 {
408         unsigned int hash;
409         struct ip_vs_conn *cp, *ret=NULL;
410 
411         /*
412          *      Check for "full" addressed entries
413          */
414         hash = ip_vs_conn_hashkey_param(p, true);
415 
416         rcu_read_lock();
417 
418         hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[hash], c_list) {
419                 if (p->vport == cp->cport && p->cport == cp->dport &&
420                     cp->af == p->af &&
421                     ip_vs_addr_equal(p->af, p->vaddr, &cp->caddr) &&
422                     ip_vs_addr_equal(p->af, p->caddr, &cp->daddr) &&
423                     p->protocol == cp->protocol &&
424                     cp->ipvs == p->ipvs) {
425                         if (!__ip_vs_conn_get(cp))
426                                 continue;
427                         /* HIT */
428                         ret = cp;
429                         break;
430                 }
431         }
432 
433         rcu_read_unlock();
434 
435         IP_VS_DBG_BUF(9, "lookup/out %s %s:%d->%s:%d %s\n",
436                       ip_vs_proto_name(p->protocol),
437                       IP_VS_DBG_ADDR(p->af, p->caddr), ntohs(p->cport),
438                       IP_VS_DBG_ADDR(p->af, p->vaddr), ntohs(p->vport),
439                       ret ? "hit" : "not hit");
440 
441         return ret;
442 }
443 
444 struct ip_vs_conn *
445 ip_vs_conn_out_get_proto(struct netns_ipvs *ipvs, int af,
446                          const struct sk_buff *skb,
447                          const struct ip_vs_iphdr *iph)
448 {
449         struct ip_vs_conn_param p;
450 
451         if (ip_vs_conn_fill_param_proto(ipvs, af, skb, iph, &p))
452                 return NULL;
453 
454         return ip_vs_conn_out_get(&p);
455 }
456 EXPORT_SYMBOL_GPL(ip_vs_conn_out_get_proto);
457 
458 /*
459  *      Put back the conn and restart its timer with its timeout
460  */
461 static void __ip_vs_conn_put_timer(struct ip_vs_conn *cp)
462 {
463         unsigned long t = (cp->flags & IP_VS_CONN_F_ONE_PACKET) ?
464                 0 : cp->timeout;
465         mod_timer(&cp->timer, jiffies+t);
466 
467         __ip_vs_conn_put(cp);
468 }
469 
470 void ip_vs_conn_put(struct ip_vs_conn *cp)
471 {
472         if ((cp->flags & IP_VS_CONN_F_ONE_PACKET) &&
473             (refcount_read(&cp->refcnt) == 1) &&
474             !timer_pending(&cp->timer))
475                 /* expire connection immediately */
476                 ip_vs_conn_expire(&cp->timer);
477         else
478                 __ip_vs_conn_put_timer(cp);
479 }
480 
481 /*
482  *      Fill a no_client_port connection with a client port number
483  */
484 void ip_vs_conn_fill_cport(struct ip_vs_conn *cp, __be16 cport)
485 {
486         if (ip_vs_conn_unhash(cp)) {
487                 spin_lock_bh(&cp->lock);
488                 if (cp->flags & IP_VS_CONN_F_NO_CPORT) {
489                         atomic_dec(&ip_vs_conn_no_cport_cnt);
490                         cp->flags &= ~IP_VS_CONN_F_NO_CPORT;
491                         cp->cport = cport;
492                 }
493                 spin_unlock_bh(&cp->lock);
494 
495                 /* hash on new dport */
496                 ip_vs_conn_hash(cp);
497         }
498 }
499 
500 
501 /*
502  *      Bind a connection entry with the corresponding packet_xmit.
503  *      Called by ip_vs_conn_new.
504  */
505 static inline void ip_vs_bind_xmit(struct ip_vs_conn *cp)
506 {
507         switch (IP_VS_FWD_METHOD(cp)) {
508         case IP_VS_CONN_F_MASQ:
509                 cp->packet_xmit = ip_vs_nat_xmit;
510                 break;
511 
512         case IP_VS_CONN_F_TUNNEL:
513 #ifdef CONFIG_IP_VS_IPV6
514                 if (cp->daf == AF_INET6)
515                         cp->packet_xmit = ip_vs_tunnel_xmit_v6;
516                 else
517 #endif
518                         cp->packet_xmit = ip_vs_tunnel_xmit;
519                 break;
520 
521         case IP_VS_CONN_F_DROUTE:
522                 cp->packet_xmit = ip_vs_dr_xmit;
523                 break;
524 
525         case IP_VS_CONN_F_LOCALNODE:
526                 cp->packet_xmit = ip_vs_null_xmit;
527                 break;
528 
529         case IP_VS_CONN_F_BYPASS:
530                 cp->packet_xmit = ip_vs_bypass_xmit;
531                 break;
532         }
533 }
534 
535 #ifdef CONFIG_IP_VS_IPV6
536 static inline void ip_vs_bind_xmit_v6(struct ip_vs_conn *cp)
537 {
538         switch (IP_VS_FWD_METHOD(cp)) {
539         case IP_VS_CONN_F_MASQ:
540                 cp->packet_xmit = ip_vs_nat_xmit_v6;
541                 break;
542 
543         case IP_VS_CONN_F_TUNNEL:
544                 if (cp->daf == AF_INET6)
545                         cp->packet_xmit = ip_vs_tunnel_xmit_v6;
546                 else
547                         cp->packet_xmit = ip_vs_tunnel_xmit;
548                 break;
549 
550         case IP_VS_CONN_F_DROUTE:
551                 cp->packet_xmit = ip_vs_dr_xmit_v6;
552                 break;
553 
554         case IP_VS_CONN_F_LOCALNODE:
555                 cp->packet_xmit = ip_vs_null_xmit;
556                 break;
557 
558         case IP_VS_CONN_F_BYPASS:
559                 cp->packet_xmit = ip_vs_bypass_xmit_v6;
560                 break;
561         }
562 }
563 #endif
564 
565 
566 static inline int ip_vs_dest_totalconns(struct ip_vs_dest *dest)
567 {
568         return atomic_read(&dest->activeconns)
569                 + atomic_read(&dest->inactconns);
570 }
571 
572 /*
573  *      Bind a connection entry with a virtual service destination
574  *      Called just after a new connection entry is created.
575  */
576 static inline void
577 ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest *dest)
578 {
579         unsigned int conn_flags;
580         __u32 flags;
581 
582         /* if dest is NULL, then return directly */
583         if (!dest)
584                 return;
585 
586         /* Increase the refcnt counter of the dest */
587         ip_vs_dest_hold(dest);
588 
589         conn_flags = atomic_read(&dest->conn_flags);
590         if (cp->protocol != IPPROTO_UDP)
591                 conn_flags &= ~IP_VS_CONN_F_ONE_PACKET;
592         flags = cp->flags;
593         /* Bind with the destination and its corresponding transmitter */
594         if (flags & IP_VS_CONN_F_SYNC) {
595                 /* if the connection is not template and is created
596                  * by sync, preserve the activity flag.
597                  */
598                 if (!(flags & IP_VS_CONN_F_TEMPLATE))
599                         conn_flags &= ~IP_VS_CONN_F_INACTIVE;
600                 /* connections inherit forwarding method from dest */
601                 flags &= ~(IP_VS_CONN_F_FWD_MASK | IP_VS_CONN_F_NOOUTPUT);
602         }
603         flags |= conn_flags;
604         cp->flags = flags;
605         cp->dest = dest;
606 
607         IP_VS_DBG_BUF(7, "Bind-dest %s c:%s:%d v:%s:%d "
608                       "d:%s:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
609                       "dest->refcnt:%d\n",
610                       ip_vs_proto_name(cp->protocol),
611                       IP_VS_DBG_ADDR(cp->af, &cp->caddr), ntohs(cp->cport),
612                       IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
613                       IP_VS_DBG_ADDR(cp->daf, &cp->daddr), ntohs(cp->dport),
614                       ip_vs_fwd_tag(cp), cp->state,
615                       cp->flags, refcount_read(&cp->refcnt),
616                       refcount_read(&dest->refcnt));
617 
618         /* Update the connection counters */
619         if (!(flags & IP_VS_CONN_F_TEMPLATE)) {
620                 /* It is a normal connection, so modify the counters
621                  * according to the flags, later the protocol can
622                  * update them on state change
623                  */
624                 if (!(flags & IP_VS_CONN_F_INACTIVE))
625                         atomic_inc(&dest->activeconns);
626                 else
627                         atomic_inc(&dest->inactconns);
628         } else {
629                 /* It is a persistent connection/template, so increase
630                    the persistent connection counter */
631                 atomic_inc(&dest->persistconns);
632         }
633 
634         if (dest->u_threshold != 0 &&
635             ip_vs_dest_totalconns(dest) >= dest->u_threshold)
636                 dest->flags |= IP_VS_DEST_F_OVERLOAD;
637 }
638 
639 
640 /*
641  * Check if there is a destination for the connection, if so
642  * bind the connection to the destination.
643  */
644 void ip_vs_try_bind_dest(struct ip_vs_conn *cp)
645 {
646         struct ip_vs_dest *dest;
647 
648         rcu_read_lock();
649 
650         /* This function is only invoked by the synchronization code. We do
651          * not currently support heterogeneous pools with synchronization,
652          * so we can make the assumption that the svc_af is the same as the
653          * dest_af
654          */
655         dest = ip_vs_find_dest(cp->ipvs, cp->af, cp->af, &cp->daddr,
656                                cp->dport, &cp->vaddr, cp->vport,
657                                cp->protocol, cp->fwmark, cp->flags);
658         if (dest) {
659                 struct ip_vs_proto_data *pd;
660 
661                 spin_lock_bh(&cp->lock);
662                 if (cp->dest) {
663                         spin_unlock_bh(&cp->lock);
664                         rcu_read_unlock();
665                         return;
666                 }
667 
668                 /* Applications work depending on the forwarding method
669                  * but better to reassign them always when binding dest */
670                 if (cp->app)
671                         ip_vs_unbind_app(cp);
672 
673                 ip_vs_bind_dest(cp, dest);
674                 spin_unlock_bh(&cp->lock);
675 
676                 /* Update its packet transmitter */
677                 cp->packet_xmit = NULL;
678 #ifdef CONFIG_IP_VS_IPV6
679                 if (cp->af == AF_INET6)
680                         ip_vs_bind_xmit_v6(cp);
681                 else
682 #endif
683                         ip_vs_bind_xmit(cp);
684 
685                 pd = ip_vs_proto_data_get(cp->ipvs, cp->protocol);
686                 if (pd && atomic_read(&pd->appcnt))
687                         ip_vs_bind_app(cp, pd->pp);
688         }
689         rcu_read_unlock();
690 }
691 
692 
693 /*
694  *      Unbind a connection entry with its VS destination
695  *      Called by the ip_vs_conn_expire function.
696  */
697 static inline void ip_vs_unbind_dest(struct ip_vs_conn *cp)
698 {
699         struct ip_vs_dest *dest = cp->dest;
700 
701         if (!dest)
702                 return;
703 
704         IP_VS_DBG_BUF(7, "Unbind-dest %s c:%s:%d v:%s:%d "
705                       "d:%s:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
706                       "dest->refcnt:%d\n",
707                       ip_vs_proto_name(cp->protocol),
708                       IP_VS_DBG_ADDR(cp->af, &cp->caddr), ntohs(cp->cport),
709                       IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
710                       IP_VS_DBG_ADDR(cp->daf, &cp->daddr), ntohs(cp->dport),
711                       ip_vs_fwd_tag(cp), cp->state,
712                       cp->flags, refcount_read(&cp->refcnt),
713                       refcount_read(&dest->refcnt));
714 
715         /* Update the connection counters */
716         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
717                 /* It is a normal connection, so decrease the inactconns
718                    or activeconns counter */
719                 if (cp->flags & IP_VS_CONN_F_INACTIVE) {
720                         atomic_dec(&dest->inactconns);
721                 } else {
722                         atomic_dec(&dest->activeconns);
723                 }
724         } else {
725                 /* It is a persistent connection/template, so decrease
726                    the persistent connection counter */
727                 atomic_dec(&dest->persistconns);
728         }
729 
730         if (dest->l_threshold != 0) {
731                 if (ip_vs_dest_totalconns(dest) < dest->l_threshold)
732                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
733         } else if (dest->u_threshold != 0) {
734                 if (ip_vs_dest_totalconns(dest) * 4 < dest->u_threshold * 3)
735                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
736         } else {
737                 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
738                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
739         }
740 
741         ip_vs_dest_put(dest);
742 }
743 
744 static int expire_quiescent_template(struct netns_ipvs *ipvs,
745                                      struct ip_vs_dest *dest)
746 {
747 #ifdef CONFIG_SYSCTL
748         return ipvs->sysctl_expire_quiescent_template &&
749                 (atomic_read(&dest->weight) == 0);
750 #else
751         return 0;
752 #endif
753 }
754 
755 /*
756  *      Checking if the destination of a connection template is available.
757  *      If available, return 1, otherwise invalidate this connection
758  *      template and return 0.
759  */
760 int ip_vs_check_template(struct ip_vs_conn *ct, struct ip_vs_dest *cdest)
761 {
762         struct ip_vs_dest *dest = ct->dest;
763         struct netns_ipvs *ipvs = ct->ipvs;
764 
765         /*
766          * Checking the dest server status.
767          */
768         if ((dest == NULL) ||
769             !(dest->flags & IP_VS_DEST_F_AVAILABLE) ||
770             expire_quiescent_template(ipvs, dest) ||
771             (cdest && (dest != cdest))) {
772                 IP_VS_DBG_BUF(9, "check_template: dest not available for "
773                               "protocol %s s:%s:%d v:%s:%d "
774                               "-> d:%s:%d\n",
775                               ip_vs_proto_name(ct->protocol),
776                               IP_VS_DBG_ADDR(ct->af, &ct->caddr),
777                               ntohs(ct->cport),
778                               IP_VS_DBG_ADDR(ct->af, &ct->vaddr),
779                               ntohs(ct->vport),
780                               IP_VS_DBG_ADDR(ct->daf, &ct->daddr),
781                               ntohs(ct->dport));
782 
783                 /*
784                  * Invalidate the connection template
785                  */
786                 if (ct->vport != htons(0xffff)) {
787                         if (ip_vs_conn_unhash(ct)) {
788                                 ct->dport = htons(0xffff);
789                                 ct->vport = htons(0xffff);
790                                 ct->cport = 0;
791                                 ip_vs_conn_hash(ct);
792                         }
793                 }
794 
795                 /*
796                  * Simply decrease the refcnt of the template,
797                  * don't restart its timer.
798                  */
799                 __ip_vs_conn_put(ct);
800                 return 0;
801         }
802         return 1;
803 }
804 
805 static void ip_vs_conn_rcu_free(struct rcu_head *head)
806 {
807         struct ip_vs_conn *cp = container_of(head, struct ip_vs_conn,
808                                              rcu_head);
809 
810         ip_vs_pe_put(cp->pe);
811         kfree(cp->pe_data);
812         kmem_cache_free(ip_vs_conn_cachep, cp);
813 }
814 
815 static void ip_vs_conn_expire(struct timer_list *t)
816 {
817         struct ip_vs_conn *cp = from_timer(cp, t, timer);
818         struct netns_ipvs *ipvs = cp->ipvs;
819 
820         /*
821          *      do I control anybody?
822          */
823         if (atomic_read(&cp->n_control))
824                 goto expire_later;
825 
826         /* Unlink conn if not referenced anymore */
827         if (likely(ip_vs_conn_unlink(cp))) {
828                 /* delete the timer if it is activated by other users */
829                 del_timer(&cp->timer);
830 
831                 /* does anybody control me? */
832                 if (cp->control)
833                         ip_vs_control_del(cp);
834 
835                 if ((cp->flags & IP_VS_CONN_F_NFCT) &&
836                     !(cp->flags & IP_VS_CONN_F_ONE_PACKET)) {
837                         /* Do not access conntracks during subsys cleanup
838                          * because nf_conntrack_find_get can not be used after
839                          * conntrack cleanup for the net.
840                          */
841                         smp_rmb();
842                         if (ipvs->enable)
843                                 ip_vs_conn_drop_conntrack(cp);
844                 }
845 
846                 if (unlikely(cp->app != NULL))
847                         ip_vs_unbind_app(cp);
848                 ip_vs_unbind_dest(cp);
849                 if (cp->flags & IP_VS_CONN_F_NO_CPORT)
850                         atomic_dec(&ip_vs_conn_no_cport_cnt);
851                 if (cp->flags & IP_VS_CONN_F_ONE_PACKET)
852                         ip_vs_conn_rcu_free(&cp->rcu_head);
853                 else
854                         call_rcu(&cp->rcu_head, ip_vs_conn_rcu_free);
855                 atomic_dec(&ipvs->conn_count);
856                 return;
857         }
858 
859   expire_later:
860         IP_VS_DBG(7, "delayed: conn->refcnt=%d conn->n_control=%d\n",
861                   refcount_read(&cp->refcnt),
862                   atomic_read(&cp->n_control));
863 
864         refcount_inc(&cp->refcnt);
865         cp->timeout = 60*HZ;
866 
867         if (ipvs->sync_state & IP_VS_STATE_MASTER)
868                 ip_vs_sync_conn(ipvs, cp, sysctl_sync_threshold(ipvs));
869 
870         __ip_vs_conn_put_timer(cp);
871 }
872 
873 /* Modify timer, so that it expires as soon as possible.
874  * Can be called without reference only if under RCU lock.
875  */
876 void ip_vs_conn_expire_now(struct ip_vs_conn *cp)
877 {
878         /* Using mod_timer_pending will ensure the timer is not
879          * modified after the final del_timer in ip_vs_conn_expire.
880          */
881         if (timer_pending(&cp->timer) &&
882             time_after(cp->timer.expires, jiffies))
883                 mod_timer_pending(&cp->timer, jiffies);
884 }
885 
886 
887 /*
888  *      Create a new connection entry and hash it into the ip_vs_conn_tab
889  */
890 struct ip_vs_conn *
891 ip_vs_conn_new(const struct ip_vs_conn_param *p, int dest_af,
892                const union nf_inet_addr *daddr, __be16 dport, unsigned int flags,
893                struct ip_vs_dest *dest, __u32 fwmark)
894 {
895         struct ip_vs_conn *cp;
896         struct netns_ipvs *ipvs = p->ipvs;
897         struct ip_vs_proto_data *pd = ip_vs_proto_data_get(p->ipvs,
898                                                            p->protocol);
899 
900         cp = kmem_cache_alloc(ip_vs_conn_cachep, GFP_ATOMIC);
901         if (cp == NULL) {
902                 IP_VS_ERR_RL("%s(): no memory\n", __func__);
903                 return NULL;
904         }
905 
906         INIT_HLIST_NODE(&cp->c_list);
907         timer_setup(&cp->timer, ip_vs_conn_expire, 0);
908         cp->ipvs           = ipvs;
909         cp->af             = p->af;
910         cp->daf            = dest_af;
911         cp->protocol       = p->protocol;
912         ip_vs_addr_set(p->af, &cp->caddr, p->caddr);
913         cp->cport          = p->cport;
914         /* proto should only be IPPROTO_IP if p->vaddr is a fwmark */
915         ip_vs_addr_set(p->protocol == IPPROTO_IP ? AF_UNSPEC : p->af,
916                        &cp->vaddr, p->vaddr);
917         cp->vport          = p->vport;
918         ip_vs_addr_set(cp->daf, &cp->daddr, daddr);
919         cp->dport          = dport;
920         cp->flags          = flags;
921         cp->fwmark         = fwmark;
922         if (flags & IP_VS_CONN_F_TEMPLATE && p->pe) {
923                 ip_vs_pe_get(p->pe);
924                 cp->pe = p->pe;
925                 cp->pe_data = p->pe_data;
926                 cp->pe_data_len = p->pe_data_len;
927         } else {
928                 cp->pe = NULL;
929                 cp->pe_data = NULL;
930                 cp->pe_data_len = 0;
931         }
932         spin_lock_init(&cp->lock);
933 
934         /*
935          * Set the entry is referenced by the current thread before hashing
936          * it in the table, so that other thread run ip_vs_random_dropentry
937          * but cannot drop this entry.
938          */
939         refcount_set(&cp->refcnt, 1);
940 
941         cp->control = NULL;
942         atomic_set(&cp->n_control, 0);
943         atomic_set(&cp->in_pkts, 0);
944 
945         cp->packet_xmit = NULL;
946         cp->app = NULL;
947         cp->app_data = NULL;
948         /* reset struct ip_vs_seq */
949         cp->in_seq.delta = 0;
950         cp->out_seq.delta = 0;
951 
952         atomic_inc(&ipvs->conn_count);
953         if (flags & IP_VS_CONN_F_NO_CPORT)
954                 atomic_inc(&ip_vs_conn_no_cport_cnt);
955 
956         /* Bind the connection with a destination server */
957         cp->dest = NULL;
958         ip_vs_bind_dest(cp, dest);
959 
960         /* Set its state and timeout */
961         cp->state = 0;
962         cp->old_state = 0;
963         cp->timeout = 3*HZ;
964         cp->sync_endtime = jiffies & ~3UL;
965 
966         /* Bind its packet transmitter */
967 #ifdef CONFIG_IP_VS_IPV6
968         if (p->af == AF_INET6)
969                 ip_vs_bind_xmit_v6(cp);
970         else
971 #endif
972                 ip_vs_bind_xmit(cp);
973 
974         if (unlikely(pd && atomic_read(&pd->appcnt)))
975                 ip_vs_bind_app(cp, pd->pp);
976 
977         /*
978          * Allow conntrack to be preserved. By default, conntrack
979          * is created and destroyed for every packet.
980          * Sometimes keeping conntrack can be useful for
981          * IP_VS_CONN_F_ONE_PACKET too.
982          */
983 
984         if (ip_vs_conntrack_enabled(ipvs))
985                 cp->flags |= IP_VS_CONN_F_NFCT;
986 
987         /* Hash it in the ip_vs_conn_tab finally */
988         ip_vs_conn_hash(cp);
989 
990         return cp;
991 }
992 
993 /*
994  *      /proc/net/ip_vs_conn entries
995  */
996 #ifdef CONFIG_PROC_FS
997 struct ip_vs_iter_state {
998         struct seq_net_private  p;
999         struct hlist_head       *l;
1000 };
1001 
1002 static void *ip_vs_conn_array(struct seq_file *seq, loff_t pos)
1003 {
1004         int idx;
1005         struct ip_vs_conn *cp;
1006         struct ip_vs_iter_state *iter = seq->private;
1007 
1008         for (idx = 0; idx < ip_vs_conn_tab_size; idx++) {
1009                 hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[idx], c_list) {
1010                         /* __ip_vs_conn_get() is not needed by
1011                          * ip_vs_conn_seq_show and ip_vs_conn_sync_seq_show
1012                          */
1013                         if (pos-- == 0) {
1014                                 iter->l = &ip_vs_conn_tab[idx];
1015                                 return cp;
1016                         }
1017                 }
1018                 cond_resched_rcu();
1019         }
1020 
1021         return NULL;
1022 }
1023 
1024 static void *ip_vs_conn_seq_start(struct seq_file *seq, loff_t *pos)
1025         __acquires(RCU)
1026 {
1027         struct ip_vs_iter_state *iter = seq->private;
1028 
1029         iter->l = NULL;
1030         rcu_read_lock();
1031         return *pos ? ip_vs_conn_array(seq, *pos - 1) :SEQ_START_TOKEN;
1032 }
1033 
1034 static void *ip_vs_conn_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1035 {
1036         struct ip_vs_conn *cp = v;
1037         struct ip_vs_iter_state *iter = seq->private;
1038         struct hlist_node *e;
1039         struct hlist_head *l = iter->l;
1040         int idx;
1041 
1042         ++*pos;
1043         if (v == SEQ_START_TOKEN)
1044                 return ip_vs_conn_array(seq, 0);
1045 
1046         /* more on same hash chain? */
1047         e = rcu_dereference(hlist_next_rcu(&cp->c_list));
1048         if (e)
1049                 return hlist_entry(e, struct ip_vs_conn, c_list);
1050 
1051         idx = l - ip_vs_conn_tab;
1052         while (++idx < ip_vs_conn_tab_size) {
1053                 hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[idx], c_list) {
1054                         iter->l = &ip_vs_conn_tab[idx];
1055                         return cp;
1056                 }
1057                 cond_resched_rcu();
1058         }
1059         iter->l = NULL;
1060         return NULL;
1061 }
1062 
1063 static void ip_vs_conn_seq_stop(struct seq_file *seq, void *v)
1064         __releases(RCU)
1065 {
1066         rcu_read_unlock();
1067 }
1068 
1069 static int ip_vs_conn_seq_show(struct seq_file *seq, void *v)
1070 {
1071 
1072         if (v == SEQ_START_TOKEN)
1073                 seq_puts(seq,
1074    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Expires PEName PEData\n");
1075         else {
1076                 const struct ip_vs_conn *cp = v;
1077                 struct net *net = seq_file_net(seq);
1078                 char pe_data[IP_VS_PENAME_MAXLEN + IP_VS_PEDATA_MAXLEN + 3];
1079                 size_t len = 0;
1080                 char dbuf[IP_VS_ADDRSTRLEN];
1081 
1082                 if (!net_eq(cp->ipvs->net, net))
1083                         return 0;
1084                 if (cp->pe_data) {
1085                         pe_data[0] = ' ';
1086                         len = strlen(cp->pe->name);
1087                         memcpy(pe_data + 1, cp->pe->name, len);
1088                         pe_data[len + 1] = ' ';
1089                         len += 2;
1090                         len += cp->pe->show_pe_data(cp, pe_data + len);
1091                 }
1092                 pe_data[len] = '\0';
1093 
1094 #ifdef CONFIG_IP_VS_IPV6
1095                 if (cp->daf == AF_INET6)
1096                         snprintf(dbuf, sizeof(dbuf), "%pI6", &cp->daddr.in6);
1097                 else
1098 #endif
1099                         snprintf(dbuf, sizeof(dbuf), "%08X",
1100                                  ntohl(cp->daddr.ip));
1101 
1102 #ifdef CONFIG_IP_VS_IPV6
1103                 if (cp->af == AF_INET6)
1104                         seq_printf(seq, "%-3s %pI6 %04X %pI6 %04X "
1105                                 "%s %04X %-11s %7lu%s\n",
1106                                 ip_vs_proto_name(cp->protocol),
1107                                 &cp->caddr.in6, ntohs(cp->cport),
1108                                 &cp->vaddr.in6, ntohs(cp->vport),
1109                                 dbuf, ntohs(cp->dport),
1110                                 ip_vs_state_name(cp->protocol, cp->state),
1111                                 (cp->timer.expires-jiffies)/HZ, pe_data);
1112                 else
1113 #endif
1114                         seq_printf(seq,
1115                                 "%-3s %08X %04X %08X %04X"
1116                                 " %s %04X %-11s %7lu%s\n",
1117                                 ip_vs_proto_name(cp->protocol),
1118                                 ntohl(cp->caddr.ip), ntohs(cp->cport),
1119                                 ntohl(cp->vaddr.ip), ntohs(cp->vport),
1120                                 dbuf, ntohs(cp->dport),
1121                                 ip_vs_state_name(cp->protocol, cp->state),
1122                                 (cp->timer.expires-jiffies)/HZ, pe_data);
1123         }
1124         return 0;
1125 }
1126 
1127 static const struct seq_operations ip_vs_conn_seq_ops = {
1128         .start = ip_vs_conn_seq_start,
1129         .next  = ip_vs_conn_seq_next,
1130         .stop  = ip_vs_conn_seq_stop,
1131         .show  = ip_vs_conn_seq_show,
1132 };
1133 
1134 static int ip_vs_conn_open(struct inode *inode, struct file *file)
1135 {
1136         return seq_open_net(inode, file, &ip_vs_conn_seq_ops,
1137                             sizeof(struct ip_vs_iter_state));
1138 }
1139 
1140 static const struct file_operations ip_vs_conn_fops = {
1141         .open    = ip_vs_conn_open,
1142         .read    = seq_read,
1143         .llseek  = seq_lseek,
1144         .release = seq_release_net,
1145 };
1146 
1147 static const char *ip_vs_origin_name(unsigned int flags)
1148 {
1149         if (flags & IP_VS_CONN_F_SYNC)
1150                 return "SYNC";
1151         else
1152                 return "LOCAL";
1153 }
1154 
1155 static int ip_vs_conn_sync_seq_show(struct seq_file *seq, void *v)
1156 {
1157         char dbuf[IP_VS_ADDRSTRLEN];
1158 
1159         if (v == SEQ_START_TOKEN)
1160                 seq_puts(seq,
1161    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Origin Expires\n");
1162         else {
1163                 const struct ip_vs_conn *cp = v;
1164                 struct net *net = seq_file_net(seq);
1165 
1166                 if (!net_eq(cp->ipvs->net, net))
1167                         return 0;
1168 
1169 #ifdef CONFIG_IP_VS_IPV6
1170                 if (cp->daf == AF_INET6)
1171                         snprintf(dbuf, sizeof(dbuf), "%pI6", &cp->daddr.in6);
1172                 else
1173 #endif
1174                         snprintf(dbuf, sizeof(dbuf), "%08X",
1175                                  ntohl(cp->daddr.ip));
1176 
1177 #ifdef CONFIG_IP_VS_IPV6
1178                 if (cp->af == AF_INET6)
1179                         seq_printf(seq, "%-3s %pI6 %04X %pI6 %04X "
1180                                 "%s %04X %-11s %-6s %7lu\n",
1181                                 ip_vs_proto_name(cp->protocol),
1182                                 &cp->caddr.in6, ntohs(cp->cport),
1183                                 &cp->vaddr.in6, ntohs(cp->vport),
1184                                 dbuf, ntohs(cp->dport),
1185                                 ip_vs_state_name(cp->protocol, cp->state),
1186                                 ip_vs_origin_name(cp->flags),
1187                                 (cp->timer.expires-jiffies)/HZ);
1188                 else
1189 #endif
1190                         seq_printf(seq,
1191                                 "%-3s %08X %04X %08X %04X "
1192                                 "%s %04X %-11s %-6s %7lu\n",
1193                                 ip_vs_proto_name(cp->protocol),
1194                                 ntohl(cp->caddr.ip), ntohs(cp->cport),
1195                                 ntohl(cp->vaddr.ip), ntohs(cp->vport),
1196                                 dbuf, ntohs(cp->dport),
1197                                 ip_vs_state_name(cp->protocol, cp->state),
1198                                 ip_vs_origin_name(cp->flags),
1199                                 (cp->timer.expires-jiffies)/HZ);
1200         }
1201         return 0;
1202 }
1203 
1204 static const struct seq_operations ip_vs_conn_sync_seq_ops = {
1205         .start = ip_vs_conn_seq_start,
1206         .next  = ip_vs_conn_seq_next,
1207         .stop  = ip_vs_conn_seq_stop,
1208         .show  = ip_vs_conn_sync_seq_show,
1209 };
1210 
1211 static int ip_vs_conn_sync_open(struct inode *inode, struct file *file)
1212 {
1213         return seq_open_net(inode, file, &ip_vs_conn_sync_seq_ops,
1214                             sizeof(struct ip_vs_iter_state));
1215 }
1216 
1217 static const struct file_operations ip_vs_conn_sync_fops = {
1218         .open    = ip_vs_conn_sync_open,
1219         .read    = seq_read,
1220         .llseek  = seq_lseek,
1221         .release = seq_release_net,
1222 };
1223 
1224 #endif
1225 
1226 
1227 /*
1228  *      Randomly drop connection entries before running out of memory
1229  */
1230 static inline int todrop_entry(struct ip_vs_conn *cp)
1231 {
1232         /*
1233          * The drop rate array needs tuning for real environments.
1234          * Called from timer bh only => no locking
1235          */
1236         static const char todrop_rate[9] = {0, 1, 2, 3, 4, 5, 6, 7, 8};
1237         static char todrop_counter[9] = {0};
1238         int i;
1239 
1240         /* if the conn entry hasn't lasted for 60 seconds, don't drop it.
1241            This will leave enough time for normal connection to get
1242            through. */
1243         if (time_before(cp->timeout + jiffies, cp->timer.expires + 60*HZ))
1244                 return 0;
1245 
1246         /* Don't drop the entry if its number of incoming packets is not
1247            located in [0, 8] */
1248         i = atomic_read(&cp->in_pkts);
1249         if (i > 8 || i < 0) return 0;
1250 
1251         if (!todrop_rate[i]) return 0;
1252         if (--todrop_counter[i] > 0) return 0;
1253 
1254         todrop_counter[i] = todrop_rate[i];
1255         return 1;
1256 }
1257 
1258 static inline bool ip_vs_conn_ops_mode(struct ip_vs_conn *cp)
1259 {
1260         struct ip_vs_service *svc;
1261 
1262         if (!cp->dest)
1263                 return false;
1264         svc = rcu_dereference(cp->dest->svc);
1265         return svc && (svc->flags & IP_VS_SVC_F_ONEPACKET);
1266 }
1267 
1268 /* Called from keventd and must protect itself from softirqs */
1269 void ip_vs_random_dropentry(struct netns_ipvs *ipvs)
1270 {
1271         int idx;
1272         struct ip_vs_conn *cp, *cp_c;
1273 
1274         rcu_read_lock();
1275         /*
1276          * Randomly scan 1/32 of the whole table every second
1277          */
1278         for (idx = 0; idx < (ip_vs_conn_tab_size>>5); idx++) {
1279                 unsigned int hash = prandom_u32() & ip_vs_conn_tab_mask;
1280 
1281                 hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[hash], c_list) {
1282                         if (cp->ipvs != ipvs)
1283                                 continue;
1284                         if (cp->flags & IP_VS_CONN_F_TEMPLATE) {
1285                                 if (atomic_read(&cp->n_control) ||
1286                                     !ip_vs_conn_ops_mode(cp))
1287                                         continue;
1288                                 else
1289                                         /* connection template of OPS */
1290                                         goto try_drop;
1291                         }
1292                         if (cp->protocol == IPPROTO_TCP) {
1293                                 switch(cp->state) {
1294                                 case IP_VS_TCP_S_SYN_RECV:
1295                                 case IP_VS_TCP_S_SYNACK:
1296                                         break;
1297 
1298                                 case IP_VS_TCP_S_ESTABLISHED:
1299                                         if (todrop_entry(cp))
1300                                                 break;
1301                                         continue;
1302 
1303                                 default:
1304                                         continue;
1305                                 }
1306                         } else if (cp->protocol == IPPROTO_SCTP) {
1307                                 switch (cp->state) {
1308                                 case IP_VS_SCTP_S_INIT1:
1309                                 case IP_VS_SCTP_S_INIT:
1310                                         break;
1311                                 case IP_VS_SCTP_S_ESTABLISHED:
1312                                         if (todrop_entry(cp))
1313                                                 break;
1314                                         continue;
1315                                 default:
1316                                         continue;
1317                                 }
1318                         } else {
1319 try_drop:
1320                                 if (!todrop_entry(cp))
1321                                         continue;
1322                         }
1323 
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 
1339 
1340 /*
1341  *      Flush all the connection entries in the ip_vs_conn_tab
1342  */
1343 static void ip_vs_conn_flush(struct netns_ipvs *ipvs)
1344 {
1345         int idx;
1346         struct ip_vs_conn *cp, *cp_c;
1347 
1348 flush_again:
1349         rcu_read_lock();
1350         for (idx = 0; idx < ip_vs_conn_tab_size; idx++) {
1351 
1352                 hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[idx], c_list) {
1353                         if (cp->ipvs != ipvs)
1354                                 continue;
1355                         IP_VS_DBG(4, "del connection\n");
1356                         ip_vs_conn_expire_now(cp);
1357                         cp_c = cp->control;
1358                         /* cp->control is valid only with reference to cp */
1359                         if (cp_c && __ip_vs_conn_get(cp)) {
1360                                 IP_VS_DBG(4, "del conn template\n");
1361                                 ip_vs_conn_expire_now(cp_c);
1362                                 __ip_vs_conn_put(cp);
1363                         }
1364                 }
1365                 cond_resched_rcu();
1366         }
1367         rcu_read_unlock();
1368 
1369         /* the counter may be not NULL, because maybe some conn entries
1370            are run by slow timer handler or unhashed but still referred */
1371         if (atomic_read(&ipvs->conn_count) != 0) {
1372                 schedule();
1373                 goto flush_again;
1374         }
1375 }
1376 /*
1377  * per netns init and exit
1378  */
1379 int __net_init ip_vs_conn_net_init(struct netns_ipvs *ipvs)
1380 {
1381         atomic_set(&ipvs->conn_count, 0);
1382 
1383         proc_create("ip_vs_conn", 0, ipvs->net->proc_net, &ip_vs_conn_fops);
1384         proc_create("ip_vs_conn_sync", 0, ipvs->net->proc_net,
1385                     &ip_vs_conn_sync_fops);
1386         return 0;
1387 }
1388 
1389 void __net_exit ip_vs_conn_net_cleanup(struct netns_ipvs *ipvs)
1390 {
1391         /* flush all the connection entries first */
1392         ip_vs_conn_flush(ipvs);
1393         remove_proc_entry("ip_vs_conn", ipvs->net->proc_net);
1394         remove_proc_entry("ip_vs_conn_sync", ipvs->net->proc_net);
1395 }
1396 
1397 int __init ip_vs_conn_init(void)
1398 {
1399         int idx;
1400 
1401         /* Compute size and mask */
1402         ip_vs_conn_tab_size = 1 << ip_vs_conn_tab_bits;
1403         ip_vs_conn_tab_mask = ip_vs_conn_tab_size - 1;
1404 
1405         /*
1406          * Allocate the connection hash table and initialize its list heads
1407          */
1408         ip_vs_conn_tab = vmalloc(ip_vs_conn_tab_size * sizeof(*ip_vs_conn_tab));
1409         if (!ip_vs_conn_tab)
1410                 return -ENOMEM;
1411 
1412         /* Allocate ip_vs_conn slab cache */
1413         ip_vs_conn_cachep = kmem_cache_create("ip_vs_conn",
1414                                               sizeof(struct ip_vs_conn), 0,
1415                                               SLAB_HWCACHE_ALIGN, NULL);
1416         if (!ip_vs_conn_cachep) {
1417                 vfree(ip_vs_conn_tab);
1418                 return -ENOMEM;
1419         }
1420 
1421         pr_info("Connection hash table configured "
1422                 "(size=%d, memory=%ldKbytes)\n",
1423                 ip_vs_conn_tab_size,
1424                 (long)(ip_vs_conn_tab_size*sizeof(struct list_head))/1024);
1425         IP_VS_DBG(0, "Each connection entry needs %zd bytes at least\n",
1426                   sizeof(struct ip_vs_conn));
1427 
1428         for (idx = 0; idx < ip_vs_conn_tab_size; idx++)
1429                 INIT_HLIST_HEAD(&ip_vs_conn_tab[idx]);
1430 
1431         for (idx = 0; idx < CT_LOCKARRAY_SIZE; idx++)  {
1432                 spin_lock_init(&__ip_vs_conntbl_lock_array[idx].l);
1433         }
1434 
1435         /* calculate the random value for connection hash */
1436         get_random_bytes(&ip_vs_conn_rnd, sizeof(ip_vs_conn_rnd));
1437 
1438         return 0;
1439 }
1440 
1441 void ip_vs_conn_cleanup(void)
1442 {
1443         /* Wait all ip_vs_conn_rcu_free() callbacks to complete */
1444         rcu_barrier();
1445         /* Release the empty cache */
1446         kmem_cache_destroy(ip_vs_conn_cachep);
1447         vfree(ip_vs_conn_tab);
1448 }
1449 

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