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 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;
  57 int ip_vs_conn_tab_mask;
  58
  59 /*
  60  *  Connection hash table: for input and output packets lookups of IPVS
  61  */
  62 static struct list_head *ip_vs_conn_tab;
  63
  64 /*  SLAB cache for IPVS connections */
  65 static struct kmem_cache *ip_vs_conn_cachep __read_mostly;
  66
  67 /*  counter for current IPVS connections */
  68 static atomic_t ip_vs_conn_count = ATOMIC_INIT(0);
  69
  70 /*  counter for no client port connections */
  71 static atomic_t ip_vs_conn_no_cport_cnt = ATOMIC_INIT(0);
  72
  73 /* random value for IPVS connection hash */
  74 static unsigned int ip_vs_conn_rnd;
  75
  76 /*
  77  *  Fine locking granularity for big connection hash table
  78  */
  79 #define CT_LOCKARRAY_BITS  4
  80 #define CT_LOCKARRAY_SIZE  (1<<CT_LOCKARRAY_BITS)
  81 #define CT_LOCKARRAY_MASK  (CT_LOCKARRAY_SIZE-1)
  82
  83 struct ip_vs_aligned_lock
  84 {
  85         rwlock_t        l;
  86 } __attribute__((__aligned__(SMP_CACHE_BYTES)));
  87
  88 /* lock array for conn table */
  89 static struct ip_vs_aligned_lock
  90 __ip_vs_conntbl_lock_array[CT_LOCKARRAY_SIZE] __cacheline_aligned;
  91
  92 static inline void ct_read_lock(unsigned key)
  93 {
  94         read_lock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  95 }
  96
  97 static inline void ct_read_unlock(unsigned key)
  98 {
  99         read_unlock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 100 }
 101
 102 static inline void ct_write_lock(unsigned key)
 103 {
 104         write_lock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 105 }
 106
 107 static inline void ct_write_unlock(unsigned key)
 108 {
 109         write_unlock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 110 }
 111
 112 static inline void ct_read_lock_bh(unsigned key)
 113 {
 114         read_lock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 115 }
 116
 117 static inline void ct_read_unlock_bh(unsigned key)
 118 {
 119         read_unlock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 120 }
 121
 122 static inline void ct_write_lock_bh(unsigned key)
 123 {
 124         write_lock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 125 }
 126
 127 static inline void ct_write_unlock_bh(unsigned key)
 128 {
 129         write_unlock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 130 }
 131
 132
 133 /*
 134  *      Returns hash value for IPVS connection entry
 135  */
 136 static unsigned int ip_vs_conn_hashkey(int af, unsigned proto,
 137                                        const union nf_inet_addr *addr,
 138                                        __be16 port)
 139 {
 140 #ifdef CONFIG_IP_VS_IPV6
 141         if (af == AF_INET6)
 142                 return jhash_3words(jhash(addr, 16, ip_vs_conn_rnd),
 143                                     (__force u32)port, proto, ip_vs_conn_rnd)
 144                         & ip_vs_conn_tab_mask;
 145 #endif
 146         return jhash_3words((__force u32)addr->ip, (__force u32)port, proto,
 147                             ip_vs_conn_rnd)
 148                 & ip_vs_conn_tab_mask;
 149 }
 150
 151
 152 /*
 153  *      Hashes ip_vs_conn in ip_vs_conn_tab by proto,addr,port.
 154  *      returns bool success.
 155  */
 156 static inline int ip_vs_conn_hash(struct ip_vs_conn *cp)
 157 {
 158         unsigned hash;
 159         int ret;
 160
 161         if (cp->flags & IP_VS_CONN_F_ONE_PACKET)
 162                 return 0;
 163
 164         /* Hash by protocol, client address and port */
 165         hash = ip_vs_conn_hashkey(cp->af, cp->protocol, &cp->caddr, cp->cport);
 166
 167         ct_write_lock(hash);
 168         spin_lock(&cp->lock);
 169
 170         if (!(cp->flags & IP_VS_CONN_F_HASHED)) {
 171                 list_add(&cp->c_list, &ip_vs_conn_tab[hash]);
 172                 cp->flags |= IP_VS_CONN_F_HASHED;
 173                 atomic_inc(&cp->refcnt);
 174                 ret = 1;
 175         } else {
 176                 pr_err("%s(): request for already hashed, called from %pF\n",
 177                        __func__, __builtin_return_address(0));
 178                 ret = 0;
 179         }
 180
 181         spin_unlock(&cp->lock);
 182         ct_write_unlock(hash);
 183
 184         return ret;
 185 }
 186
 187
 188 /*
 189  *      UNhashes ip_vs_conn from ip_vs_conn_tab.
 190  *      returns bool success.
 191  */
 192 static inline int ip_vs_conn_unhash(struct ip_vs_conn *cp)
 193 {
 194         unsigned hash;
 195         int ret;
 196
 197         /* unhash it and decrease its reference counter */
 198         hash = ip_vs_conn_hashkey(cp->af, cp->protocol, &cp->caddr, cp->cport);
 199
 200         ct_write_lock(hash);
 201         spin_lock(&cp->lock);
 202
 203         if (cp->flags & IP_VS_CONN_F_HASHED) {
 204                 list_del(&cp->c_list);
 205                 cp->flags &= ~IP_VS_CONN_F_HASHED;
 206                 atomic_dec(&cp->refcnt);
 207                 ret = 1;
 208         } else
 209                 ret = 0;
 210
 211         spin_unlock(&cp->lock);
 212         ct_write_unlock(hash);
 213
 214         return ret;
 215 }
 216
 217
 218 /*
 219  *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
 220  *  Called for pkts coming from OUTside-to-INside.
 221  *      s_addr, s_port: pkt source address (foreign host)
 222  *      d_addr, d_port: pkt dest address (load balancer)
 223  */
 224 static inline struct ip_vs_conn *__ip_vs_conn_in_get
 225 (int af, int protocol, const union nf_inet_addr *s_addr, __be16 s_port,
 226  const union nf_inet_addr *d_addr, __be16 d_port)
 227 {
 228         unsigned hash;
 229         struct ip_vs_conn *cp;
 230
 231         hash = ip_vs_conn_hashkey(af, protocol, s_addr, s_port);
 232
 233         ct_read_lock(hash);
 234
 235         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 236                 if (cp->af == af &&
 237                     ip_vs_addr_equal(af, s_addr, &cp->caddr) &&
 238                     ip_vs_addr_equal(af, d_addr, &cp->vaddr) &&
 239                     s_port == cp->cport && d_port == cp->vport &&
 240                     ((!s_port) ^ (!(cp->flags & IP_VS_CONN_F_NO_CPORT))) &&
 241                     protocol == cp->protocol) {
 242                         /* HIT */
 243                         atomic_inc(&cp->refcnt);
 244                         ct_read_unlock(hash);
 245                         return cp;
 246                 }
 247         }
 248
 249         ct_read_unlock(hash);
 250
 251         return NULL;
 252 }
 253
 254 struct ip_vs_conn *ip_vs_conn_in_get
 255 (int af, int protocol, const union nf_inet_addr *s_addr, __be16 s_port,
 256  const union nf_inet_addr *d_addr, __be16 d_port)
 257 {
 258         struct ip_vs_conn *cp;
 259
 260         cp = __ip_vs_conn_in_get(af, protocol, s_addr, s_port, d_addr, d_port);
 261         if (!cp && atomic_read(&ip_vs_conn_no_cport_cnt))
 262                 cp = __ip_vs_conn_in_get(af, protocol, s_addr, 0, d_addr,
 263                                          d_port);
 264
 265         IP_VS_DBG_BUF(9, "lookup/in %s %s:%d->%s:%d %s\n",
 266                       ip_vs_proto_name(protocol),
 267                       IP_VS_DBG_ADDR(af, s_addr), ntohs(s_port),
 268                       IP_VS_DBG_ADDR(af, d_addr), ntohs(d_port),
 269                       cp ? "hit" : "not hit");
 270
 271         return cp;
 272 }
 273
 274 struct ip_vs_conn *
 275 ip_vs_conn_in_get_proto(int af, const struct sk_buff *skb,
 276                         struct ip_vs_protocol *pp,
 277                         const struct ip_vs_iphdr *iph,
 278                         unsigned int proto_off, int inverse)
 279 {
 280         __be16 _ports[2], *pptr;
 281
 282         pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports);
 283         if (pptr == NULL)
 284                 return NULL;
 285
 286         if (likely(!inverse))
 287                 return ip_vs_conn_in_get(af, iph->protocol,
 288                                          &iph->saddr, pptr[0],
 289                                          &iph->daddr, pptr[1]);
 290         else
 291                 return ip_vs_conn_in_get(af, iph->protocol,
 292                                          &iph->daddr, pptr[1],
 293                                          &iph->saddr, pptr[0]);
 294 }
 295 EXPORT_SYMBOL_GPL(ip_vs_conn_in_get_proto);
 296
 297 /* Get reference to connection template */
 298 struct ip_vs_conn *ip_vs_ct_in_get
 299 (int af, int protocol, const union nf_inet_addr *s_addr, __be16 s_port,
 300  const union nf_inet_addr *d_addr, __be16 d_port)
 301 {
 302         unsigned hash;
 303         struct ip_vs_conn *cp;
 304
 305         hash = ip_vs_conn_hashkey(af, protocol, s_addr, s_port);
 306
 307         ct_read_lock(hash);
 308
 309         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 310                 if (cp->af == af &&
 311                     ip_vs_addr_equal(af, s_addr, &cp->caddr) &&
 312                     /* protocol should only be IPPROTO_IP if
 313                      * d_addr is a fwmark */
 314                     ip_vs_addr_equal(protocol == IPPROTO_IP ? AF_UNSPEC : af,
 315                                      d_addr, &cp->vaddr) &&
 316                     s_port == cp->cport && d_port == cp->vport &&
 317                     cp->flags & IP_VS_CONN_F_TEMPLATE &&
 318                     protocol == cp->protocol) {
 319                         /* HIT */
 320                         atomic_inc(&cp->refcnt);
 321                         goto out;
 322                 }
 323         }
 324         cp = NULL;
 325
 326   out:
 327         ct_read_unlock(hash);
 328
 329         IP_VS_DBG_BUF(9, "template lookup/in %s %s:%d->%s:%d %s\n",
 330                       ip_vs_proto_name(protocol),
 331                       IP_VS_DBG_ADDR(af, s_addr), ntohs(s_port),
 332                       IP_VS_DBG_ADDR(af, d_addr), ntohs(d_port),
 333                       cp ? "hit" : "not hit");
 334
 335         return cp;
 336 }
 337
 338 /*
 339  *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
 340  *  Called for pkts coming from inside-to-OUTside.
 341  *      s_addr, s_port: pkt source address (inside host)
 342  *      d_addr, d_port: pkt dest address (foreign host)
 343  */
 344 struct ip_vs_conn *ip_vs_conn_out_get
 345 (int af, int protocol, const union nf_inet_addr *s_addr, __be16 s_port,
 346  const union nf_inet_addr *d_addr, __be16 d_port)
 347 {
 348         unsigned hash;
 349         struct ip_vs_conn *cp, *ret=NULL;
 350
 351         /*
 352          *      Check for "full" addressed entries
 353          */
 354         hash = ip_vs_conn_hashkey(af, protocol, d_addr, d_port);
 355
 356         ct_read_lock(hash);
 357
 358         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 359                 if (cp->af == af &&
 360                     ip_vs_addr_equal(af, d_addr, &cp->caddr) &&
 361                     ip_vs_addr_equal(af, s_addr, &cp->daddr) &&
 362                     d_port == cp->cport && s_port == cp->dport &&
 363                     protocol == cp->protocol) {
 364                         /* HIT */
 365                         atomic_inc(&cp->refcnt);
 366                         ret = cp;
 367                         break;
 368                 }
 369         }
 370
 371         ct_read_unlock(hash);
 372
 373         IP_VS_DBG_BUF(9, "lookup/out %s %s:%d->%s:%d %s\n",
 374                       ip_vs_proto_name(protocol),
 375                       IP_VS_DBG_ADDR(af, s_addr), ntohs(s_port),
 376                       IP_VS_DBG_ADDR(af, d_addr), ntohs(d_port),
 377                       ret ? "hit" : "not hit");
 378
 379         return ret;
 380 }
 381
 382 struct ip_vs_conn *
 383 ip_vs_conn_out_get_proto(int af, const struct sk_buff *skb,
 384                          struct ip_vs_protocol *pp,
 385                          const struct ip_vs_iphdr *iph,
 386                          unsigned int proto_off, int inverse)
 387 {
 388         __be16 _ports[2], *pptr;
 389
 390         pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports);
 391         if (pptr == NULL)
 392                 return NULL;
 393
 394         if (likely(!inverse))
 395                 return ip_vs_conn_out_get(af, iph->protocol,
 396                                           &iph->saddr, pptr[0],
 397                                           &iph->daddr, pptr[1]);
 398         else
 399                 return ip_vs_conn_out_get(af, iph->protocol,
 400                                           &iph->daddr, pptr[1],
 401                                           &iph->saddr, pptr[0]);
 402 }
 403 EXPORT_SYMBOL_GPL(ip_vs_conn_out_get_proto);
 404
 405 /*
 406  *      Put back the conn and restart its timer with its timeout
 407  */
 408 void ip_vs_conn_put(struct ip_vs_conn *cp)
 409 {
 410         unsigned long t = (cp->flags & IP_VS_CONN_F_ONE_PACKET) ?
 411                 0 : cp->timeout;
 412         mod_timer(&cp->timer, jiffies+t);
 413
 414         __ip_vs_conn_put(cp);
 415 }
 416
 417
 418 /*
 419  *      Fill a no_client_port connection with a client port number
 420  */
 421 void ip_vs_conn_fill_cport(struct ip_vs_conn *cp, __be16 cport)
 422 {
 423         if (ip_vs_conn_unhash(cp)) {
 424                 spin_lock(&cp->lock);
 425                 if (cp->flags & IP_VS_CONN_F_NO_CPORT) {
 426                         atomic_dec(&ip_vs_conn_no_cport_cnt);
 427                         cp->flags &= ~IP_VS_CONN_F_NO_CPORT;
 428                         cp->cport = cport;
 429                 }
 430                 spin_unlock(&cp->lock);
 431
 432                 /* hash on new dport */
 433                 ip_vs_conn_hash(cp);
 434         }
 435 }
 436
 437
 438 /*
 439  *      Bind a connection entry with the corresponding packet_xmit.
 440  *      Called by ip_vs_conn_new.
 441  */
 442 static inline void ip_vs_bind_xmit(struct ip_vs_conn *cp)
 443 {
 444         switch (IP_VS_FWD_METHOD(cp)) {
 445         case IP_VS_CONN_F_MASQ:
 446                 cp->packet_xmit = ip_vs_nat_xmit;
 447                 break;
 448
 449         case IP_VS_CONN_F_TUNNEL:
 450                 cp->packet_xmit = ip_vs_tunnel_xmit;
 451                 break;
 452
 453         case IP_VS_CONN_F_DROUTE:
 454                 cp->packet_xmit = ip_vs_dr_xmit;
 455                 break;
 456
 457         case IP_VS_CONN_F_LOCALNODE:
 458                 cp->packet_xmit = ip_vs_null_xmit;
 459                 break;
 460
 461         case IP_VS_CONN_F_BYPASS:
 462                 cp->packet_xmit = ip_vs_bypass_xmit;
 463                 break;
 464         }
 465 }
 466
 467 #ifdef CONFIG_IP_VS_IPV6
 468 static inline void ip_vs_bind_xmit_v6(struct ip_vs_conn *cp)
 469 {
 470         switch (IP_VS_FWD_METHOD(cp)) {
 471         case IP_VS_CONN_F_MASQ:
 472                 cp->packet_xmit = ip_vs_nat_xmit_v6;
 473                 break;
 474
 475         case IP_VS_CONN_F_TUNNEL:
 476                 cp->packet_xmit = ip_vs_tunnel_xmit_v6;
 477                 break;
 478
 479         case IP_VS_CONN_F_DROUTE:
 480                 cp->packet_xmit = ip_vs_dr_xmit_v6;
 481                 break;
 482
 483         case IP_VS_CONN_F_LOCALNODE:
 484                 cp->packet_xmit = ip_vs_null_xmit;
 485                 break;
 486
 487         case IP_VS_CONN_F_BYPASS:
 488                 cp->packet_xmit = ip_vs_bypass_xmit_v6;
 489                 break;
 490         }
 491 }
 492 #endif
 493
 494
 495 static inline int ip_vs_dest_totalconns(struct ip_vs_dest *dest)
 496 {
 497         return atomic_read(&dest->activeconns)
 498                 + atomic_read(&dest->inactconns);
 499 }
 500
 501 /*
 502  *      Bind a connection entry with a virtual service destination
 503  *      Called just after a new connection entry is created.
 504  */
 505 static inline void
 506 ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest *dest)
 507 {
 508         /* if dest is NULL, then return directly */
 509         if (!dest)
 510                 return;
 511
 512         /* Increase the refcnt counter of the dest */
 513         atomic_inc(&dest->refcnt);
 514
 515         /* Bind with the destination and its corresponding transmitter */
 516         if ((cp->flags & IP_VS_CONN_F_SYNC) &&
 517             (!(cp->flags & IP_VS_CONN_F_TEMPLATE)))
 518                 /* if the connection is not template and is created
 519                  * by sync, preserve the activity flag.
 520                  */
 521                 cp->flags |= atomic_read(&dest->conn_flags) &
 522                              (~IP_VS_CONN_F_INACTIVE);
 523         else
 524                 cp->flags |= atomic_read(&dest->conn_flags);
 525         cp->dest = dest;
 526
 527         IP_VS_DBG_BUF(7, "Bind-dest %s c:%s:%d v:%s:%d "
 528                       "d:%s:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 529                       "dest->refcnt:%d\n",
 530                       ip_vs_proto_name(cp->protocol),
 531                       IP_VS_DBG_ADDR(cp->af, &cp->caddr), ntohs(cp->cport),
 532                       IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
 533                       IP_VS_DBG_ADDR(cp->af, &cp->daddr), ntohs(cp->dport),
 534                       ip_vs_fwd_tag(cp), cp->state,
 535                       cp->flags, atomic_read(&cp->refcnt),
 536                       atomic_read(&dest->refcnt));
 537
 538         /* Update the connection counters */
 539         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
 540                 /* It is a normal connection, so increase the inactive
 541                    connection counter because it is in TCP SYNRECV
 542                    state (inactive) or other protocol inacive state */
 543                 if ((cp->flags & IP_VS_CONN_F_SYNC) &&
 544                     (!(cp->flags & IP_VS_CONN_F_INACTIVE)))
 545                         atomic_inc(&dest->activeconns);
 546                 else
 547                         atomic_inc(&dest->inactconns);
 548         } else {
 549                 /* It is a persistent connection/template, so increase
 550                    the peristent connection counter */
 551                 atomic_inc(&dest->persistconns);
 552         }
 553
 554         if (dest->u_threshold != 0 &&
 555             ip_vs_dest_totalconns(dest) >= dest->u_threshold)
 556                 dest->flags |= IP_VS_DEST_F_OVERLOAD;
 557 }
 558
 559
 560 /*
 561  * Check if there is a destination for the connection, if so
 562  * bind the connection to the destination.
 563  */
 564 struct ip_vs_dest *ip_vs_try_bind_dest(struct ip_vs_conn *cp)
 565 {
 566         struct ip_vs_dest *dest;
 567
 568         if ((cp) && (!cp->dest)) {
 569                 dest = ip_vs_find_dest(cp->af, &cp->daddr, cp->dport,
 570                                        &cp->vaddr, cp->vport,
 571                                        cp->protocol);
 572                 ip_vs_bind_dest(cp, dest);
 573                 return dest;
 574         } else
 575                 return NULL;
 576 }
 577
 578
 579 /*
 580  *      Unbind a connection entry with its VS destination
 581  *      Called by the ip_vs_conn_expire function.
 582  */
 583 static inline void ip_vs_unbind_dest(struct ip_vs_conn *cp)
 584 {
 585         struct ip_vs_dest *dest = cp->dest;
 586
 587         if (!dest)
 588                 return;
 589
 590         IP_VS_DBG_BUF(7, "Unbind-dest %s c:%s:%d v:%s:%d "
 591                       "d:%s:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 592                       "dest->refcnt:%d\n",
 593                       ip_vs_proto_name(cp->protocol),
 594                       IP_VS_DBG_ADDR(cp->af, &cp->caddr), ntohs(cp->cport),
 595                       IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
 596                       IP_VS_DBG_ADDR(cp->af, &cp->daddr), ntohs(cp->dport),
 597                       ip_vs_fwd_tag(cp), cp->state,
 598                       cp->flags, atomic_read(&cp->refcnt),
 599                       atomic_read(&dest->refcnt));
 600
 601         /* Update the connection counters */
 602         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
 603                 /* It is a normal connection, so decrease the inactconns
 604                    or activeconns counter */
 605                 if (cp->flags & IP_VS_CONN_F_INACTIVE) {
 606                         atomic_dec(&dest->inactconns);
 607                 } else {
 608                         atomic_dec(&dest->activeconns);
 609                 }
 610         } else {
 611                 /* It is a persistent connection/template, so decrease
 612                    the peristent connection counter */
 613                 atomic_dec(&dest->persistconns);
 614         }
 615
 616         if (dest->l_threshold != 0) {
 617                 if (ip_vs_dest_totalconns(dest) < dest->l_threshold)
 618                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 619         } else if (dest->u_threshold != 0) {
 620                 if (ip_vs_dest_totalconns(dest) * 4 < dest->u_threshold * 3)
 621                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 622         } else {
 623                 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
 624                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 625         }
 626
 627         /*
 628          * Simply decrease the refcnt of the dest, because the
 629          * dest will be either in service's destination list
 630          * or in the trash.
 631          */
 632         atomic_dec(&dest->refcnt);
 633 }
 634
 635
 636 /*
 637  *      Checking if the destination of a connection template is available.
 638  *      If available, return 1, otherwise invalidate this connection
 639  *      template and return 0.
 640  */
 641 int ip_vs_check_template(struct ip_vs_conn *ct)
 642 {
 643         struct ip_vs_dest *dest = ct->dest;
 644
 645         /*
 646          * Checking the dest server status.
 647          */
 648         if ((dest == NULL) ||
 649             !(dest->flags & IP_VS_DEST_F_AVAILABLE) ||
 650             (sysctl_ip_vs_expire_quiescent_template &&
 651              (atomic_read(&dest->weight) == 0))) {
 652                 IP_VS_DBG_BUF(9, "check_template: dest not available for "
 653                               "protocol %s s:%s:%d v:%s:%d "
 654                               "-> d:%s:%d\n",
 655                               ip_vs_proto_name(ct->protocol),
 656                               IP_VS_DBG_ADDR(ct->af, &ct->caddr),
 657                               ntohs(ct->cport),
 658                               IP_VS_DBG_ADDR(ct->af, &ct->vaddr),
 659                               ntohs(ct->vport),
 660                               IP_VS_DBG_ADDR(ct->af, &ct->daddr),
 661                               ntohs(ct->dport));
 662
 663                 /*
 664                  * Invalidate the connection template
 665                  */
 666                 if (ct->vport != htons(0xffff)) {
 667                         if (ip_vs_conn_unhash(ct)) {
 668                                 ct->dport = htons(0xffff);
 669                                 ct->vport = htons(0xffff);
 670                                 ct->cport = 0;
 671                                 ip_vs_conn_hash(ct);
 672                         }
 673                 }
 674
 675                 /*
 676                  * Simply decrease the refcnt of the template,
 677                  * don't restart its timer.
 678                  */
 679                 atomic_dec(&ct->refcnt);
 680                 return 0;
 681         }
 682         return 1;
 683 }
 684
 685 static void ip_vs_conn_expire(unsigned long data)
 686 {
 687         struct ip_vs_conn *cp = (struct ip_vs_conn *)data;
 688
 689         cp->timeout = 60*HZ;
 690
 691         /*
 692          *      hey, I'm using it
 693          */
 694         atomic_inc(&cp->refcnt);
 695
 696         /*
 697          *      do I control anybody?
 698          */
 699         if (atomic_read(&cp->n_control))
 700                 goto expire_later;
 701
 702         /*
 703          *      unhash it if it is hashed in the conn table
 704          */
 705         if (!ip_vs_conn_unhash(cp) && !(cp->flags & IP_VS_CONN_F_ONE_PACKET))
 706                 goto expire_later;
 707
 708         /*
 709          *      refcnt==1 implies I'm the only one referrer
 710          */
 711         if (likely(atomic_read(&cp->refcnt) == 1)) {
 712                 /* delete the timer if it is activated by other users */
 713                 if (timer_pending(&cp->timer))
 714                         del_timer(&cp->timer);
 715
 716                 /* does anybody control me? */
 717                 if (cp->control)
 718                         ip_vs_control_del(cp);
 719
 720                 if (unlikely(cp->app != NULL))
 721                         ip_vs_unbind_app(cp);
 722                 ip_vs_unbind_dest(cp);
 723                 if (cp->flags & IP_VS_CONN_F_NO_CPORT)
 724                         atomic_dec(&ip_vs_conn_no_cport_cnt);
 725                 atomic_dec(&ip_vs_conn_count);
 726
 727                 kmem_cache_free(ip_vs_conn_cachep, cp);
 728                 return;
 729         }
 730
 731         /* hash it back to the table */
 732         ip_vs_conn_hash(cp);
 733
 734   expire_later:
 735         IP_VS_DBG(7, "delayed: conn->refcnt-1=%d conn->n_control=%d\n",
 736                   atomic_read(&cp->refcnt)-1,
 737                   atomic_read(&cp->n_control));
 738
 739         ip_vs_conn_put(cp);
 740 }
 741
 742
 743 void ip_vs_conn_expire_now(struct ip_vs_conn *cp)
 744 {
 745         if (del_timer(&cp->timer))
 746                 mod_timer(&cp->timer, jiffies);
 747 }
 748
 749
 750 /*
 751  *      Create a new connection entry and hash it into the ip_vs_conn_tab
 752  */
 753 struct ip_vs_conn *
 754 ip_vs_conn_new(int af, int proto, const union nf_inet_addr *caddr, __be16 cport,
 755                const union nf_inet_addr *vaddr, __be16 vport,
 756                const union nf_inet_addr *daddr, __be16 dport, unsigned flags,
 757                struct ip_vs_dest *dest)
 758 {
 759         struct ip_vs_conn *cp;
 760         struct ip_vs_protocol *pp = ip_vs_proto_get(proto);
 761
 762         cp = kmem_cache_zalloc(ip_vs_conn_cachep, GFP_ATOMIC);
 763         if (cp == NULL) {
 764                 IP_VS_ERR_RL("%s(): no memory\n", __func__);
 765                 return NULL;
 766         }
 767
 768         INIT_LIST_HEAD(&cp->c_list);
 769         setup_timer(&cp->timer, ip_vs_conn_expire, (unsigned long)cp);
 770         cp->af             = af;
 771         cp->protocol       = proto;
 772         ip_vs_addr_copy(af, &cp->caddr, caddr);
 773         cp->cport          = cport;
 774         ip_vs_addr_copy(af, &cp->vaddr, vaddr);
 775         cp->vport          = vport;
 776         /* proto should only be IPPROTO_IP if d_addr is a fwmark */
 777         ip_vs_addr_copy(proto == IPPROTO_IP ? AF_UNSPEC : af,
 778                         &cp->daddr, daddr);
 779         cp->dport          = dport;
 780         cp->flags          = flags;
 781         spin_lock_init(&cp->lock);
 782
 783         /*
 784          * Set the entry is referenced by the current thread before hashing
 785          * it in the table, so that other thread run ip_vs_random_dropentry
 786          * but cannot drop this entry.
 787          */
 788         atomic_set(&cp->refcnt, 1);
 789
 790         atomic_set(&cp->n_control, 0);
 791         atomic_set(&cp->in_pkts, 0);
 792
 793         atomic_inc(&ip_vs_conn_count);
 794         if (flags & IP_VS_CONN_F_NO_CPORT)
 795                 atomic_inc(&ip_vs_conn_no_cport_cnt);
 796
 797         /* Bind the connection with a destination server */
 798         ip_vs_bind_dest(cp, dest);
 799
 800         /* Set its state and timeout */
 801         cp->state = 0;
 802         cp->timeout = 3*HZ;
 803
 804         /* Bind its packet transmitter */
 805 #ifdef CONFIG_IP_VS_IPV6
 806         if (af == AF_INET6)
 807                 ip_vs_bind_xmit_v6(cp);
 808         else
 809 #endif
 810                 ip_vs_bind_xmit(cp);
 811
 812         if (unlikely(pp && atomic_read(&pp->appcnt)))
 813                 ip_vs_bind_app(cp, pp);
 814
 815         /* Hash it in the ip_vs_conn_tab finally */
 816         ip_vs_conn_hash(cp);
 817
 818         return cp;
 819 }
 820
 821
 822 /*
 823  *      /proc/net/ip_vs_conn entries
 824  */
 825 #ifdef CONFIG_PROC_FS
 826
 827 static void *ip_vs_conn_array(struct seq_file *seq, loff_t pos)
 828 {
 829         int idx;
 830         struct ip_vs_conn *cp;
 831
 832         for (idx = 0; idx < ip_vs_conn_tab_size; idx++) {
 833                 ct_read_lock_bh(idx);
 834                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 835                         if (pos-- == 0) {
 836                                 seq->private = &ip_vs_conn_tab[idx];
 837                                 return cp;
 838                         }
 839                 }
 840                 ct_read_unlock_bh(idx);
 841         }
 842
 843         return NULL;
 844 }
 845
 846 static void *ip_vs_conn_seq_start(struct seq_file *seq, loff_t *pos)
 847 {
 848         seq->private = NULL;
 849         return *pos ? ip_vs_conn_array(seq, *pos - 1) :SEQ_START_TOKEN;
 850 }
 851
 852 static void *ip_vs_conn_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 853 {
 854         struct ip_vs_conn *cp = v;
 855         struct list_head *e, *l = seq->private;
 856         int idx;
 857
 858         ++*pos;
 859         if (v == SEQ_START_TOKEN)
 860                 return ip_vs_conn_array(seq, 0);
 861
 862         /* more on same hash chain? */
 863         if ((e = cp->c_list.next) != l)
 864                 return list_entry(e, struct ip_vs_conn, c_list);
 865
 866         idx = l - ip_vs_conn_tab;
 867         ct_read_unlock_bh(idx);
 868
 869         while (++idx < ip_vs_conn_tab_size) {
 870                 ct_read_lock_bh(idx);
 871                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 872                         seq->private = &ip_vs_conn_tab[idx];
 873                         return cp;
 874                 }
 875                 ct_read_unlock_bh(idx);
 876         }
 877         seq->private = NULL;
 878         return NULL;
 879 }
 880
 881 static void ip_vs_conn_seq_stop(struct seq_file *seq, void *v)
 882 {
 883         struct list_head *l = seq->private;
 884
 885         if (l)
 886                 ct_read_unlock_bh(l - ip_vs_conn_tab);
 887 }
 888
 889 static int ip_vs_conn_seq_show(struct seq_file *seq, void *v)
 890 {
 891
 892         if (v == SEQ_START_TOKEN)
 893                 seq_puts(seq,
 894    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Expires\n");
 895         else {
 896                 const struct ip_vs_conn *cp = v;
 897
 898 #ifdef CONFIG_IP_VS_IPV6
 899                 if (cp->af == AF_INET6)
 900                         seq_printf(seq, "%-3s %pI6 %04X %pI6 %04X %pI6 %04X %-11s %7lu\n",
 901                                 ip_vs_proto_name(cp->protocol),
 902                                 &cp->caddr.in6, ntohs(cp->cport),
 903                                 &cp->vaddr.in6, ntohs(cp->vport),
 904                                 &cp->daddr.in6, ntohs(cp->dport),
 905                                 ip_vs_state_name(cp->protocol, cp->state),
 906                                 (cp->timer.expires-jiffies)/HZ);
 907                 else
 908 #endif
 909                         seq_printf(seq,
 910                                 "%-3s %08X %04X %08X %04X"
 911                                 " %08X %04X %-11s %7lu\n",
 912                                 ip_vs_proto_name(cp->protocol),
 913                                 ntohl(cp->caddr.ip), ntohs(cp->cport),
 914                                 ntohl(cp->vaddr.ip), ntohs(cp->vport),
 915                                 ntohl(cp->daddr.ip), ntohs(cp->dport),
 916                                 ip_vs_state_name(cp->protocol, cp->state),
 917                                 (cp->timer.expires-jiffies)/HZ);
 918         }
 919         return 0;
 920 }
 921
 922 static const struct seq_operations ip_vs_conn_seq_ops = {
 923         .start = ip_vs_conn_seq_start,
 924         .next  = ip_vs_conn_seq_next,
 925         .stop  = ip_vs_conn_seq_stop,
 926         .show  = ip_vs_conn_seq_show,
 927 };
 928
 929 static int ip_vs_conn_open(struct inode *inode, struct file *file)
 930 {
 931         return seq_open(file, &ip_vs_conn_seq_ops);
 932 }
 933
 934 static const struct file_operations ip_vs_conn_fops = {
 935         .owner   = THIS_MODULE,
 936         .open    = ip_vs_conn_open,
 937         .read    = seq_read,
 938         .llseek  = seq_lseek,
 939         .release = seq_release,
 940 };
 941
 942 static const char *ip_vs_origin_name(unsigned flags)
 943 {
 944         if (flags & IP_VS_CONN_F_SYNC)
 945                 return "SYNC";
 946         else
 947                 return "LOCAL";
 948 }
 949
 950 static int ip_vs_conn_sync_seq_show(struct seq_file *seq, void *v)
 951 {
 952
 953         if (v == SEQ_START_TOKEN)
 954                 seq_puts(seq,
 955    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Origin Expires\n");
 956         else {
 957                 const struct ip_vs_conn *cp = v;
 958
 959 #ifdef CONFIG_IP_VS_IPV6
 960                 if (cp->af == AF_INET6)
 961                         seq_printf(seq, "%-3s %pI6 %04X %pI6 %04X %pI6 %04X %-11s %-6s %7lu\n",
 962                                 ip_vs_proto_name(cp->protocol),
 963                                 &cp->caddr.in6, ntohs(cp->cport),
 964                                 &cp->vaddr.in6, ntohs(cp->vport),
 965                                 &cp->daddr.in6, ntohs(cp->dport),
 966                                 ip_vs_state_name(cp->protocol, cp->state),
 967                                 ip_vs_origin_name(cp->flags),
 968                                 (cp->timer.expires-jiffies)/HZ);
 969                 else
 970 #endif
 971                         seq_printf(seq,
 972                                 "%-3s %08X %04X %08X %04X "
 973                                 "%08X %04X %-11s %-6s %7lu\n",
 974                                 ip_vs_proto_name(cp->protocol),
 975                                 ntohl(cp->caddr.ip), ntohs(cp->cport),
 976                                 ntohl(cp->vaddr.ip), ntohs(cp->vport),
 977                                 ntohl(cp->daddr.ip), ntohs(cp->dport),
 978                                 ip_vs_state_name(cp->protocol, cp->state),
 979                                 ip_vs_origin_name(cp->flags),
 980                                 (cp->timer.expires-jiffies)/HZ);
 981         }
 982         return 0;
 983 }
 984
 985 static const struct seq_operations ip_vs_conn_sync_seq_ops = {
 986         .start = ip_vs_conn_seq_start,
 987         .next  = ip_vs_conn_seq_next,
 988         .stop  = ip_vs_conn_seq_stop,
 989         .show  = ip_vs_conn_sync_seq_show,
 990 };
 991
 992 static int ip_vs_conn_sync_open(struct inode *inode, struct file *file)
 993 {
 994         return seq_open(file, &ip_vs_conn_sync_seq_ops);
 995 }
 996
 997 static const struct file_operations ip_vs_conn_sync_fops = {
 998         .owner   = THIS_MODULE,
 999         .open    = ip_vs_conn_sync_open,
1000         .read    = seq_read,
1001         .llseek  = seq_lseek,
1002         .release = seq_release,
1003 };
1004
1005 #endif
1006
1007
1008 /*
1009  *      Randomly drop connection entries before running out of memory
1010  */
1011 static inline int todrop_entry(struct ip_vs_conn *cp)
1012 {
1013         /*
1014          * The drop rate array needs tuning for real environments.
1015          * Called from timer bh only => no locking
1016          */
1017         static const char todrop_rate[9] = {0, 1, 2, 3, 4, 5, 6, 7, 8};
1018         static char todrop_counter[9] = {0};
1019         int i;
1020
1021         /* if the conn entry hasn't lasted for 60 seconds, don't drop it.
1022            This will leave enough time for normal connection to get
1023            through. */
1024         if (time_before(cp->timeout + jiffies, cp->timer.expires + 60*HZ))
1025                 return 0;
1026
1027         /* Don't drop the entry if its number of incoming packets is not
1028            located in [0, 8] */
1029         i = atomic_read(&cp->in_pkts);
1030         if (i > 8 || i < 0) return 0;
1031
1032         if (!todrop_rate[i]) return 0;
1033         if (--todrop_counter[i] > 0) return 0;
1034
1035         todrop_counter[i] = todrop_rate[i];
1036         return 1;
1037 }
1038
1039 /* Called from keventd and must protect itself from softirqs */
1040 void ip_vs_random_dropentry(void)
1041 {
1042         int idx;
1043         struct ip_vs_conn *cp;
1044
1045         /*
1046          * Randomly scan 1/32 of the whole table every second
1047          */
1048         for (idx = 0; idx < (ip_vs_conn_tab_size>>5); idx++) {
1049                 unsigned hash = net_random() & ip_vs_conn_tab_mask;
1050
1051                 /*
1052                  *  Lock is actually needed in this loop.
1053                  */
1054                 ct_write_lock_bh(hash);
1055
1056                 list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
1057                         if (cp->flags & IP_VS_CONN_F_TEMPLATE)
1058                                 /* connection template */
1059                                 continue;
1060
1061                         if (cp->protocol == IPPROTO_TCP) {
1062                                 switch(cp->state) {
1063                                 case IP_VS_TCP_S_SYN_RECV:
1064                                 case IP_VS_TCP_S_SYNACK:
1065                                         break;
1066
1067                                 case IP_VS_TCP_S_ESTABLISHED:
1068                                         if (todrop_entry(cp))
1069                                                 break;
1070                                         continue;
1071
1072                                 default:
1073                                         continue;
1074                                 }
1075                         } else {
1076                                 if (!todrop_entry(cp))
1077                                         continue;
1078                         }
1079
1080                         IP_VS_DBG(4, "del connection\n");
1081                         ip_vs_conn_expire_now(cp);
1082                         if (cp->control) {
1083                                 IP_VS_DBG(4, "del conn template\n");
1084                                 ip_vs_conn_expire_now(cp->control);
1085                         }
1086                 }
1087                 ct_write_unlock_bh(hash);
1088         }
1089 }
1090
1091
1092 /*
1093  *      Flush all the connection entries in the ip_vs_conn_tab
1094  */
1095 static void ip_vs_conn_flush(void)
1096 {
1097         int idx;
1098         struct ip_vs_conn *cp;
1099
1100   flush_again:
1101         for (idx = 0; idx < ip_vs_conn_tab_size; idx++) {
1102                 /*
1103                  *  Lock is actually needed in this loop.
1104                  */
1105                 ct_write_lock_bh(idx);
1106
1107                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
1108
1109                         IP_VS_DBG(4, "del connection\n");
1110                         ip_vs_conn_expire_now(cp);
1111                         if (cp->control) {
1112                                 IP_VS_DBG(4, "del conn template\n");
1113                                 ip_vs_conn_expire_now(cp->control);
1114                         }
1115                 }
1116                 ct_write_unlock_bh(idx);
1117         }
1118
1119         /* the counter may be not NULL, because maybe some conn entries
1120            are run by slow timer handler or unhashed but still referred */
1121         if (atomic_read(&ip_vs_conn_count) != 0) {
1122                 schedule();
1123                 goto flush_again;
1124         }
1125 }
1126
1127
1128 int __init ip_vs_conn_init(void)
1129 {
1130         int idx;
1131
1132         /* Compute size and mask */
1133         ip_vs_conn_tab_size = 1 << ip_vs_conn_tab_bits;
1134         ip_vs_conn_tab_mask = ip_vs_conn_tab_size - 1;
1135
1136         /*
1137          * Allocate the connection hash table and initialize its list heads
1138          */
1139         ip_vs_conn_tab = vmalloc(ip_vs_conn_tab_size *
1140                                  sizeof(struct list_head));
1141         if (!ip_vs_conn_tab)
1142                 return -ENOMEM;
1143
1144         /* Allocate ip_vs_conn slab cache */
1145         ip_vs_conn_cachep = kmem_cache_create("ip_vs_conn",
1146                                               sizeof(struct ip_vs_conn), 0,
1147                                               SLAB_HWCACHE_ALIGN, NULL);
1148         if (!ip_vs_conn_cachep) {
1149                 vfree(ip_vs_conn_tab);
1150                 return -ENOMEM;
1151         }
1152
1153         pr_info("Connection hash table configured "
1154                 "(size=%d, memory=%ldKbytes)\n",
1155                 ip_vs_conn_tab_size,
1156                 (long)(ip_vs_conn_tab_size*sizeof(struct list_head))/1024);
1157         IP_VS_DBG(0, "Each connection entry needs %Zd bytes at least\n",
1158                   sizeof(struct ip_vs_conn));
1159
1160         for (idx = 0; idx < ip_vs_conn_tab_size; idx++) {
1161                 INIT_LIST_HEAD(&ip_vs_conn_tab[idx]);
1162         }
1163
1164         for (idx = 0; idx < CT_LOCKARRAY_SIZE; idx++)  {
1165                 rwlock_init(&__ip_vs_conntbl_lock_array[idx].l);
1166         }
1167
1168         proc_net_fops_create(&init_net, "ip_vs_conn", 0, &ip_vs_conn_fops);
1169         proc_net_fops_create(&init_net, "ip_vs_conn_sync", 0, &ip_vs_conn_sync_fops);
1170
1171         /* calculate the random value for connection hash */
1172         get_random_bytes(&ip_vs_conn_rnd, sizeof(ip_vs_conn_rnd));
1173
1174         return 0;
1175 }
1176
1177
1178 void ip_vs_conn_cleanup(void)
1179 {
1180         /* flush all the connection entries first */
1181         ip_vs_conn_flush();
1182
1183         /* Release the empty cache */
1184         kmem_cache_destroy(ip_vs_conn_cachep);
1185         proc_net_remove(&init_net, "ip_vs_conn");
1186         proc_net_remove(&init_net, "ip_vs_conn_sync");
1187         vfree(ip_vs_conn_tab);
1188 }