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

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