net/netfilter/ipvs/ip_vs_conn.c

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