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   1 /*
   2  * IPVS         An implementation of the IP virtual server support for the
   3  *              LINUX operating system.  IPVS is now implemented as a module
   4  *              over the Netfilter framework. IPVS can be used to build a
   5  *              high-performance and highly available server based on a
   6  *              cluster of servers.
   7  *
   8  * Version:     $Id: ip_vs_conn.c,v 1.31 2003/04/18 09:03:16 wensong Exp $
   9  *
  10  * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
  11  *              Peter Kese <peter.kese@ijs.si>
  12  *              Julian Anastasov <ja@ssi.bg>
  13  *
  14  *              This program is free software; you can redistribute it and/or
  15  *              modify it under the terms of the GNU General Public License
  16  *              as published by the Free Software Foundation; either version
  17  *              2 of the License, or (at your option) any later version.
  18  *
  19  * The IPVS code for kernel 2.2 was done by Wensong Zhang and Peter Kese,
  20  * with changes/fixes from Julian Anastasov, Lars Marowsky-Bree, Horms
  21  * and others. Many code here is taken from IP MASQ code of kernel 2.2.
  22  *
  23  * Changes:
  24  *
  25  */
  26
  27 #include <linux/interrupt.h>
  28 #include <linux/in.h>
  29 #include <linux/net.h>
  30 #include <linux/kernel.h>
  31 #include <linux/module.h>
  32 #include <linux/vmalloc.h>
  33 #include <linux/proc_fs.h>              /* for proc_net_* */
  34 #include <linux/seq_file.h>
  35 #include <linux/jhash.h>
  36 #include <linux/random.h>
  37
  38 #include <net/net_namespace.h>
  39 #include <net/ip_vs.h>
  40
  41
  42 /*
  43  *  Connection hash table: for input and output packets lookups of IPVS
  44  */
  45 static struct list_head *ip_vs_conn_tab;
  46
  47 /*  SLAB cache for IPVS connections */
  48 static struct kmem_cache *ip_vs_conn_cachep __read_mostly;
  49
  50 /*  counter for current IPVS connections */
  51 static atomic_t ip_vs_conn_count = ATOMIC_INIT(0);
  52
  53 /*  counter for no client port connections */
  54 static atomic_t ip_vs_conn_no_cport_cnt = ATOMIC_INIT(0);
  55
  56 /* random value for IPVS connection hash */
  57 static unsigned int ip_vs_conn_rnd;
  58
  59 /*
  60  *  Fine locking granularity for big connection hash table
  61  */
  62 #define CT_LOCKARRAY_BITS  4
  63 #define CT_LOCKARRAY_SIZE  (1<<CT_LOCKARRAY_BITS)
  64 #define CT_LOCKARRAY_MASK  (CT_LOCKARRAY_SIZE-1)
  65
  66 struct ip_vs_aligned_lock
  67 {
  68         rwlock_t        l;
  69 } __attribute__((__aligned__(SMP_CACHE_BYTES)));
  70
  71 /* lock array for conn table */
  72 static struct ip_vs_aligned_lock
  73 __ip_vs_conntbl_lock_array[CT_LOCKARRAY_SIZE] __cacheline_aligned;
  74
  75 static inline void ct_read_lock(unsigned key)
  76 {
  77         read_lock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  78 }
  79
  80 static inline void ct_read_unlock(unsigned key)
  81 {
  82         read_unlock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  83 }
  84
  85 static inline void ct_write_lock(unsigned key)
  86 {
  87         write_lock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  88 }
  89
  90 static inline void ct_write_unlock(unsigned key)
  91 {
  92         write_unlock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  93 }
  94
  95 static inline void ct_read_lock_bh(unsigned key)
  96 {
  97         read_lock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  98 }
  99
 100 static inline void ct_read_unlock_bh(unsigned key)
 101 {
 102         read_unlock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 103 }
 104
 105 static inline void ct_write_lock_bh(unsigned key)
 106 {
 107         write_lock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 108 }
 109
 110 static inline void ct_write_unlock_bh(unsigned key)
 111 {
 112         write_unlock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 113 }
 114
 115
 116 /*
 117  *      Returns hash value for IPVS connection entry
 118  */
 119 static unsigned int ip_vs_conn_hashkey(unsigned proto, __be32 addr, __be16 port)
 120 {
 121         return jhash_3words((__force u32)addr, (__force u32)port, proto, ip_vs_conn_rnd)
 122                 & IP_VS_CONN_TAB_MASK;
 123 }
 124
 125
 126 /*
 127  *      Hashes ip_vs_conn in ip_vs_conn_tab by proto,addr,port.
 128  *      returns bool success.
 129  */
 130 static inline int ip_vs_conn_hash(struct ip_vs_conn *cp)
 131 {
 132         unsigned hash;
 133         int ret;
 134
 135         /* Hash by protocol, client address and port */
 136         hash = ip_vs_conn_hashkey(cp->protocol, cp->caddr, cp->cport);
 137
 138         ct_write_lock(hash);
 139
 140         if (!(cp->flags & IP_VS_CONN_F_HASHED)) {
 141                 list_add(&cp->c_list, &ip_vs_conn_tab[hash]);
 142                 cp->flags |= IP_VS_CONN_F_HASHED;
 143                 atomic_inc(&cp->refcnt);
 144                 ret = 1;
 145         } else {
 146                 IP_VS_ERR("ip_vs_conn_hash(): request for already hashed, "
 147                           "called from %p\n", __builtin_return_address(0));
 148                 ret = 0;
 149         }
 150
 151         ct_write_unlock(hash);
 152
 153         return ret;
 154 }
 155
 156
 157 /*
 158  *      UNhashes ip_vs_conn from ip_vs_conn_tab.
 159  *      returns bool success.
 160  */
 161 static inline int ip_vs_conn_unhash(struct ip_vs_conn *cp)
 162 {
 163         unsigned hash;
 164         int ret;
 165
 166         /* unhash it and decrease its reference counter */
 167         hash = ip_vs_conn_hashkey(cp->protocol, cp->caddr, cp->cport);
 168
 169         ct_write_lock(hash);
 170
 171         if (cp->flags & IP_VS_CONN_F_HASHED) {
 172                 list_del(&cp->c_list);
 173                 cp->flags &= ~IP_VS_CONN_F_HASHED;
 174                 atomic_dec(&cp->refcnt);
 175                 ret = 1;
 176         } else
 177                 ret = 0;
 178
 179         ct_write_unlock(hash);
 180
 181         return ret;
 182 }
 183
 184
 185 /*
 186  *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
 187  *  Called for pkts coming from OUTside-to-INside.
 188  *      s_addr, s_port: pkt source address (foreign host)
 189  *      d_addr, d_port: pkt dest address (load balancer)
 190  */
 191 static inline struct ip_vs_conn *__ip_vs_conn_in_get
 192 (int protocol, __be32 s_addr, __be16 s_port, __be32 d_addr, __be16 d_port)
 193 {
 194         unsigned hash;
 195         struct ip_vs_conn *cp;
 196
 197         hash = ip_vs_conn_hashkey(protocol, s_addr, s_port);
 198
 199         ct_read_lock(hash);
 200
 201         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 202                 if (s_addr==cp->caddr && s_port==cp->cport &&
 203                     d_port==cp->vport && d_addr==cp->vaddr &&
 204                     ((!s_port) ^ (!(cp->flags & IP_VS_CONN_F_NO_CPORT))) &&
 205                     protocol==cp->protocol) {
 206                         /* HIT */
 207                         atomic_inc(&cp->refcnt);
 208                         ct_read_unlock(hash);
 209                         return cp;
 210                 }
 211         }
 212
 213         ct_read_unlock(hash);
 214
 215         return NULL;
 216 }
 217
 218 struct ip_vs_conn *ip_vs_conn_in_get
 219 (int protocol, __be32 s_addr, __be16 s_port, __be32 d_addr, __be16 d_port)
 220 {
 221         struct ip_vs_conn *cp;
 222
 223         cp = __ip_vs_conn_in_get(protocol, s_addr, s_port, d_addr, d_port);
 224         if (!cp && atomic_read(&ip_vs_conn_no_cport_cnt))
 225                 cp = __ip_vs_conn_in_get(protocol, s_addr, 0, d_addr, d_port);
 226
 227         IP_VS_DBG(9, "lookup/in %s %u.%u.%u.%u:%d->%u.%u.%u.%u:%d %s\n",
 228                   ip_vs_proto_name(protocol),
 229                   NIPQUAD(s_addr), ntohs(s_port),
 230                   NIPQUAD(d_addr), ntohs(d_port),
 231                   cp?"hit":"not hit");
 232
 233         return cp;
 234 }
 235
 236 /* Get reference to connection template */
 237 struct ip_vs_conn *ip_vs_ct_in_get
 238 (int protocol, __be32 s_addr, __be16 s_port, __be32 d_addr, __be16 d_port)
 239 {
 240         unsigned hash;
 241         struct ip_vs_conn *cp;
 242
 243         hash = ip_vs_conn_hashkey(protocol, s_addr, s_port);
 244
 245         ct_read_lock(hash);
 246
 247         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 248                 if (s_addr==cp->caddr && s_port==cp->cport &&
 249                     d_port==cp->vport && d_addr==cp->vaddr &&
 250                     cp->flags & IP_VS_CONN_F_TEMPLATE &&
 251                     protocol==cp->protocol) {
 252                         /* HIT */
 253                         atomic_inc(&cp->refcnt);
 254                         goto out;
 255                 }
 256         }
 257         cp = NULL;
 258
 259   out:
 260         ct_read_unlock(hash);
 261
 262         IP_VS_DBG(9, "template lookup/in %s %u.%u.%u.%u:%d->%u.%u.%u.%u:%d %s\n",
 263                   ip_vs_proto_name(protocol),
 264                   NIPQUAD(s_addr), ntohs(s_port),
 265                   NIPQUAD(d_addr), ntohs(d_port),
 266                   cp?"hit":"not hit");
 267
 268         return cp;
 269 }
 270
 271 /*
 272  *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
 273  *  Called for pkts coming from inside-to-OUTside.
 274  *      s_addr, s_port: pkt source address (inside host)
 275  *      d_addr, d_port: pkt dest address (foreign host)
 276  */
 277 struct ip_vs_conn *ip_vs_conn_out_get
 278 (int protocol, __be32 s_addr, __be16 s_port, __be32 d_addr, __be16 d_port)
 279 {
 280         unsigned hash;
 281         struct ip_vs_conn *cp, *ret=NULL;
 282
 283         /*
 284          *      Check for "full" addressed entries
 285          */
 286         hash = ip_vs_conn_hashkey(protocol, d_addr, d_port);
 287
 288         ct_read_lock(hash);
 289
 290         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 291                 if (d_addr == cp->caddr && d_port == cp->cport &&
 292                     s_port == cp->dport && s_addr == cp->daddr &&
 293                     protocol == cp->protocol) {
 294                         /* HIT */
 295                         atomic_inc(&cp->refcnt);
 296                         ret = cp;
 297                         break;
 298                 }
 299         }
 300
 301         ct_read_unlock(hash);
 302
 303         IP_VS_DBG(9, "lookup/out %s %u.%u.%u.%u:%d->%u.%u.%u.%u:%d %s\n",
 304                   ip_vs_proto_name(protocol),
 305                   NIPQUAD(s_addr), ntohs(s_port),
 306                   NIPQUAD(d_addr), ntohs(d_port),
 307                   ret?"hit":"not hit");
 308
 309         return ret;
 310 }
 311
 312
 313 /*
 314  *      Put back the conn and restart its timer with its timeout
 315  */
 316 void ip_vs_conn_put(struct ip_vs_conn *cp)
 317 {
 318         /* reset it expire in its timeout */
 319         mod_timer(&cp->timer, jiffies+cp->timeout);
 320
 321         __ip_vs_conn_put(cp);
 322 }
 323
 324
 325 /*
 326  *      Fill a no_client_port connection with a client port number
 327  */
 328 void ip_vs_conn_fill_cport(struct ip_vs_conn *cp, __be16 cport)
 329 {
 330         if (ip_vs_conn_unhash(cp)) {
 331                 spin_lock(&cp->lock);
 332                 if (cp->flags & IP_VS_CONN_F_NO_CPORT) {
 333                         atomic_dec(&ip_vs_conn_no_cport_cnt);
 334                         cp->flags &= ~IP_VS_CONN_F_NO_CPORT;
 335                         cp->cport = cport;
 336                 }
 337                 spin_unlock(&cp->lock);
 338
 339                 /* hash on new dport */
 340                 ip_vs_conn_hash(cp);
 341         }
 342 }
 343
 344
 345 /*
 346  *      Bind a connection entry with the corresponding packet_xmit.
 347  *      Called by ip_vs_conn_new.
 348  */
 349 static inline void ip_vs_bind_xmit(struct ip_vs_conn *cp)
 350 {
 351         switch (IP_VS_FWD_METHOD(cp)) {
 352         case IP_VS_CONN_F_MASQ:
 353                 cp->packet_xmit = ip_vs_nat_xmit;
 354                 break;
 355
 356         case IP_VS_CONN_F_TUNNEL:
 357                 cp->packet_xmit = ip_vs_tunnel_xmit;
 358                 break;
 359
 360         case IP_VS_CONN_F_DROUTE:
 361                 cp->packet_xmit = ip_vs_dr_xmit;
 362                 break;
 363
 364         case IP_VS_CONN_F_LOCALNODE:
 365                 cp->packet_xmit = ip_vs_null_xmit;
 366                 break;
 367
 368         case IP_VS_CONN_F_BYPASS:
 369                 cp->packet_xmit = ip_vs_bypass_xmit;
 370                 break;
 371         }
 372 }
 373
 374
 375 static inline int ip_vs_dest_totalconns(struct ip_vs_dest *dest)
 376 {
 377         return atomic_read(&dest->activeconns)
 378                 + atomic_read(&dest->inactconns);
 379 }
 380
 381 /*
 382  *      Bind a connection entry with a virtual service destination
 383  *      Called just after a new connection entry is created.
 384  */
 385 static inline void
 386 ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest *dest)
 387 {
 388         /* if dest is NULL, then return directly */
 389         if (!dest)
 390                 return;
 391
 392         /* Increase the refcnt counter of the dest */
 393         atomic_inc(&dest->refcnt);
 394
 395         /* Bind with the destination and its corresponding transmitter */
 396         cp->flags |= atomic_read(&dest->conn_flags);
 397         cp->dest = dest;
 398
 399         IP_VS_DBG(7, "Bind-dest %s c:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
 400                   "d:%u.%u.%u.%u:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 401                   "dest->refcnt:%d\n",
 402                   ip_vs_proto_name(cp->protocol),
 403                   NIPQUAD(cp->caddr), ntohs(cp->cport),
 404                   NIPQUAD(cp->vaddr), ntohs(cp->vport),
 405                   NIPQUAD(cp->daddr), ntohs(cp->dport),
 406                   ip_vs_fwd_tag(cp), cp->state,
 407                   cp->flags, atomic_read(&cp->refcnt),
 408                   atomic_read(&dest->refcnt));
 409
 410         /* Update the connection counters */
 411         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
 412                 /* It is a normal connection, so increase the inactive
 413                    connection counter because it is in TCP SYNRECV
 414                    state (inactive) or other protocol inacive state */
 415                 atomic_inc(&dest->inactconns);
 416         } else {
 417                 /* It is a persistent connection/template, so increase
 418                    the peristent connection counter */
 419                 atomic_inc(&dest->persistconns);
 420         }
 421
 422         if (dest->u_threshold != 0 &&
 423             ip_vs_dest_totalconns(dest) >= dest->u_threshold)
 424                 dest->flags |= IP_VS_DEST_F_OVERLOAD;
 425 }
 426
 427
 428 /*
 429  * Check if there is a destination for the connection, if so
 430  * bind the connection to the destination.
 431  */
 432 struct ip_vs_dest *ip_vs_try_bind_dest(struct ip_vs_conn *cp)
 433 {
 434         struct ip_vs_dest *dest;
 435
 436         if ((cp) && (!cp->dest)) {
 437                 dest = ip_vs_find_dest(cp->daddr, cp->dport,
 438                                        cp->vaddr, cp->vport, cp->protocol);
 439                 ip_vs_bind_dest(cp, dest);
 440                 return dest;
 441         } else
 442                 return NULL;
 443 }
 444
 445
 446 /*
 447  *      Unbind a connection entry with its VS destination
 448  *      Called by the ip_vs_conn_expire function.
 449  */
 450 static inline void ip_vs_unbind_dest(struct ip_vs_conn *cp)
 451 {
 452         struct ip_vs_dest *dest = cp->dest;
 453
 454         if (!dest)
 455                 return;
 456
 457         IP_VS_DBG(7, "Unbind-dest %s c:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
 458                   "d:%u.%u.%u.%u:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 459                   "dest->refcnt:%d\n",
 460                   ip_vs_proto_name(cp->protocol),
 461                   NIPQUAD(cp->caddr), ntohs(cp->cport),
 462                   NIPQUAD(cp->vaddr), ntohs(cp->vport),
 463                   NIPQUAD(cp->daddr), ntohs(cp->dport),
 464                   ip_vs_fwd_tag(cp), cp->state,
 465                   cp->flags, atomic_read(&cp->refcnt),
 466                   atomic_read(&dest->refcnt));
 467
 468         /* Update the connection counters */
 469         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
 470                 /* It is a normal connection, so decrease the inactconns
 471                    or activeconns counter */
 472                 if (cp->flags & IP_VS_CONN_F_INACTIVE) {
 473                         atomic_dec(&dest->inactconns);
 474                 } else {
 475                         atomic_dec(&dest->activeconns);
 476                 }
 477         } else {
 478                 /* It is a persistent connection/template, so decrease
 479                    the peristent connection counter */
 480                 atomic_dec(&dest->persistconns);
 481         }
 482
 483         if (dest->l_threshold != 0) {
 484                 if (ip_vs_dest_totalconns(dest) < dest->l_threshold)
 485                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 486         } else if (dest->u_threshold != 0) {
 487                 if (ip_vs_dest_totalconns(dest) * 4 < dest->u_threshold * 3)
 488                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 489         } else {
 490                 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
 491                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 492         }
 493
 494         /*
 495          * Simply decrease the refcnt of the dest, because the
 496          * dest will be either in service's destination list
 497          * or in the trash.
 498          */
 499         atomic_dec(&dest->refcnt);
 500 }
 501
 502
 503 /*
 504  *      Checking if the destination of a connection template is available.
 505  *      If available, return 1, otherwise invalidate this connection
 506  *      template and return 0.
 507  */
 508 int ip_vs_check_template(struct ip_vs_conn *ct)
 509 {
 510         struct ip_vs_dest *dest = ct->dest;
 511
 512         /*
 513          * Checking the dest server status.
 514          */
 515         if ((dest == NULL) ||
 516             !(dest->flags & IP_VS_DEST_F_AVAILABLE) ||
 517             (sysctl_ip_vs_expire_quiescent_template &&
 518              (atomic_read(&dest->weight) == 0))) {
 519                 IP_VS_DBG(9, "check_template: dest not available for "
 520                           "protocol %s s:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
 521                           "-> d:%u.%u.%u.%u:%d\n",
 522                           ip_vs_proto_name(ct->protocol),
 523                           NIPQUAD(ct->caddr), ntohs(ct->cport),
 524                           NIPQUAD(ct->vaddr), ntohs(ct->vport),
 525                           NIPQUAD(ct->daddr), ntohs(ct->dport));
 526
 527                 /*
 528                  * Invalidate the connection template
 529                  */
 530                 if (ct->vport != htons(0xffff)) {
 531                         if (ip_vs_conn_unhash(ct)) {
 532                                 ct->dport = htons(0xffff);
 533                                 ct->vport = htons(0xffff);
 534                                 ct->cport = 0;
 535                                 ip_vs_conn_hash(ct);
 536                         }
 537                 }
 538
 539                 /*
 540                  * Simply decrease the refcnt of the template,
 541                  * don't restart its timer.
 542                  */
 543                 atomic_dec(&ct->refcnt);
 544                 return 0;
 545         }
 546         return 1;
 547 }
 548
 549 static void ip_vs_conn_expire(unsigned long data)
 550 {
 551         struct ip_vs_conn *cp = (struct ip_vs_conn *)data;
 552
 553         cp->timeout = 60*HZ;
 554
 555         /*
 556          *      hey, I'm using it
 557          */
 558         atomic_inc(&cp->refcnt);
 559
 560         /*
 561          *      do I control anybody?
 562          */
 563         if (atomic_read(&cp->n_control))
 564                 goto expire_later;
 565
 566         /*
 567          *      unhash it if it is hashed in the conn table
 568          */
 569         if (!ip_vs_conn_unhash(cp))
 570                 goto expire_later;
 571
 572         /*
 573          *      refcnt==1 implies I'm the only one referrer
 574          */
 575         if (likely(atomic_read(&cp->refcnt) == 1)) {
 576                 /* delete the timer if it is activated by other users */
 577                 if (timer_pending(&cp->timer))
 578                         del_timer(&cp->timer);
 579
 580                 /* does anybody control me? */
 581                 if (cp->control)
 582                         ip_vs_control_del(cp);
 583
 584                 if (unlikely(cp->app != NULL))
 585                         ip_vs_unbind_app(cp);
 586                 ip_vs_unbind_dest(cp);
 587                 if (cp->flags & IP_VS_CONN_F_NO_CPORT)
 588                         atomic_dec(&ip_vs_conn_no_cport_cnt);
 589                 atomic_dec(&ip_vs_conn_count);
 590
 591                 kmem_cache_free(ip_vs_conn_cachep, cp);
 592                 return;
 593         }
 594
 595         /* hash it back to the table */
 596         ip_vs_conn_hash(cp);
 597
 598   expire_later:
 599         IP_VS_DBG(7, "delayed: conn->refcnt-1=%d conn->n_control=%d\n",
 600                   atomic_read(&cp->refcnt)-1,
 601                   atomic_read(&cp->n_control));
 602
 603         ip_vs_conn_put(cp);
 604 }
 605
 606
 607 void ip_vs_conn_expire_now(struct ip_vs_conn *cp)
 608 {
 609         if (del_timer(&cp->timer))
 610                 mod_timer(&cp->timer, jiffies);
 611 }
 612
 613
 614 /*
 615  *      Create a new connection entry and hash it into the ip_vs_conn_tab
 616  */
 617 struct ip_vs_conn *
 618 ip_vs_conn_new(int proto, __be32 caddr, __be16 cport, __be32 vaddr, __be16 vport,
 619                __be32 daddr, __be16 dport, unsigned flags,
 620                struct ip_vs_dest *dest)
 621 {
 622         struct ip_vs_conn *cp;
 623         struct ip_vs_protocol *pp = ip_vs_proto_get(proto);
 624
 625         cp = kmem_cache_zalloc(ip_vs_conn_cachep, GFP_ATOMIC);
 626         if (cp == NULL) {
 627                 IP_VS_ERR_RL("ip_vs_conn_new: no memory available.\n");
 628                 return NULL;
 629         }
 630
 631         INIT_LIST_HEAD(&cp->c_list);
 632         setup_timer(&cp->timer, ip_vs_conn_expire, (unsigned long)cp);
 633         cp->protocol       = proto;
 634         cp->caddr          = caddr;
 635         cp->cport          = cport;
 636         cp->vaddr          = vaddr;
 637         cp->vport          = vport;
 638         cp->daddr          = daddr;
 639         cp->dport          = dport;
 640         cp->flags          = flags;
 641         spin_lock_init(&cp->lock);
 642
 643         /*
 644          * Set the entry is referenced by the current thread before hashing
 645          * it in the table, so that other thread run ip_vs_random_dropentry
 646          * but cannot drop this entry.
 647          */
 648         atomic_set(&cp->refcnt, 1);
 649
 650         atomic_set(&cp->n_control, 0);
 651         atomic_set(&cp->in_pkts, 0);
 652
 653         atomic_inc(&ip_vs_conn_count);
 654         if (flags & IP_VS_CONN_F_NO_CPORT)
 655                 atomic_inc(&ip_vs_conn_no_cport_cnt);
 656
 657         /* Bind the connection with a destination server */
 658         ip_vs_bind_dest(cp, dest);
 659
 660         /* Set its state and timeout */
 661         cp->state = 0;
 662         cp->timeout = 3*HZ;
 663
 664         /* Bind its packet transmitter */
 665         ip_vs_bind_xmit(cp);
 666
 667         if (unlikely(pp && atomic_read(&pp->appcnt)))
 668                 ip_vs_bind_app(cp, pp);
 669
 670         /* Hash it in the ip_vs_conn_tab finally */
 671         ip_vs_conn_hash(cp);
 672
 673         return cp;
 674 }
 675
 676
 677 /*
 678  *      /proc/net/ip_vs_conn entries
 679  */
 680 #ifdef CONFIG_PROC_FS
 681
 682 static void *ip_vs_conn_array(struct seq_file *seq, loff_t pos)
 683 {
 684         int idx;
 685         struct ip_vs_conn *cp;
 686
 687         for(idx = 0; idx < IP_VS_CONN_TAB_SIZE; idx++) {
 688                 ct_read_lock_bh(idx);
 689                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 690                         if (pos-- == 0) {
 691                                 seq->private = &ip_vs_conn_tab[idx];
 692                                 return cp;
 693                         }
 694                 }
 695                 ct_read_unlock_bh(idx);
 696         }
 697
 698         return NULL;
 699 }
 700
 701 static void *ip_vs_conn_seq_start(struct seq_file *seq, loff_t *pos)
 702 {
 703         seq->private = NULL;
 704         return *pos ? ip_vs_conn_array(seq, *pos - 1) :SEQ_START_TOKEN;
 705 }
 706
 707 static void *ip_vs_conn_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 708 {
 709         struct ip_vs_conn *cp = v;
 710         struct list_head *e, *l = seq->private;
 711         int idx;
 712
 713         ++*pos;
 714         if (v == SEQ_START_TOKEN)
 715                 return ip_vs_conn_array(seq, 0);
 716
 717         /* more on same hash chain? */
 718         if ((e = cp->c_list.next) != l)
 719                 return list_entry(e, struct ip_vs_conn, c_list);
 720
 721         idx = l - ip_vs_conn_tab;
 722         ct_read_unlock_bh(idx);
 723
 724         while (++idx < IP_VS_CONN_TAB_SIZE) {
 725                 ct_read_lock_bh(idx);
 726                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 727                         seq->private = &ip_vs_conn_tab[idx];
 728                         return cp;
 729                 }
 730                 ct_read_unlock_bh(idx);
 731         }
 732         seq->private = NULL;
 733         return NULL;
 734 }
 735
 736 static void ip_vs_conn_seq_stop(struct seq_file *seq, void *v)
 737 {
 738         struct list_head *l = seq->private;
 739
 740         if (l)
 741                 ct_read_unlock_bh(l - ip_vs_conn_tab);
 742 }
 743
 744 static int ip_vs_conn_seq_show(struct seq_file *seq, void *v)
 745 {
 746
 747         if (v == SEQ_START_TOKEN)
 748                 seq_puts(seq,
 749    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Expires\n");
 750         else {
 751                 const struct ip_vs_conn *cp = v;
 752
 753                 seq_printf(seq,
 754                         "%-3s %08X %04X %08X %04X %08X %04X %-11s %7lu\n",
 755                                 ip_vs_proto_name(cp->protocol),
 756                                 ntohl(cp->caddr), ntohs(cp->cport),
 757                                 ntohl(cp->vaddr), ntohs(cp->vport),
 758                                 ntohl(cp->daddr), ntohs(cp->dport),
 759                                 ip_vs_state_name(cp->protocol, cp->state),
 760                                 (cp->timer.expires-jiffies)/HZ);
 761         }
 762         return 0;
 763 }
 764
 765 static const struct seq_operations ip_vs_conn_seq_ops = {
 766         .start = ip_vs_conn_seq_start,
 767         .next  = ip_vs_conn_seq_next,
 768         .stop  = ip_vs_conn_seq_stop,
 769         .show  = ip_vs_conn_seq_show,
 770 };
 771
 772 static int ip_vs_conn_open(struct inode *inode, struct file *file)
 773 {
 774         return seq_open(file, &ip_vs_conn_seq_ops);
 775 }
 776
 777 static const struct file_operations ip_vs_conn_fops = {
 778         .owner   = THIS_MODULE,
 779         .open    = ip_vs_conn_open,
 780         .read    = seq_read,
 781         .llseek  = seq_lseek,
 782         .release = seq_release,
 783 };
 784 #endif
 785
 786
 787 /*
 788  *      Randomly drop connection entries before running out of memory
 789  */
 790 static inline int todrop_entry(struct ip_vs_conn *cp)
 791 {
 792         /*
 793          * The drop rate array needs tuning for real environments.
 794          * Called from timer bh only => no locking
 795          */
 796         static const char todrop_rate[9] = {0, 1, 2, 3, 4, 5, 6, 7, 8};
 797         static char todrop_counter[9] = {0};
 798         int i;
 799
 800         /* if the conn entry hasn't lasted for 60 seconds, don't drop it.
 801            This will leave enough time for normal connection to get
 802            through. */
 803         if (time_before(cp->timeout + jiffies, cp->timer.expires + 60*HZ))
 804                 return 0;
 805
 806         /* Don't drop the entry if its number of incoming packets is not
 807            located in [0, 8] */
 808         i = atomic_read(&cp->in_pkts);
 809         if (i > 8 || i < 0) return 0;
 810
 811         if (!todrop_rate[i]) return 0;
 812         if (--todrop_counter[i] > 0) return 0;
 813
 814         todrop_counter[i] = todrop_rate[i];
 815         return 1;
 816 }
 817
 818 /* Called from keventd and must protect itself from softirqs */
 819 void ip_vs_random_dropentry(void)
 820 {
 821         int idx;
 822         struct ip_vs_conn *cp;
 823
 824         /*
 825          * Randomly scan 1/32 of the whole table every second
 826          */
 827         for (idx = 0; idx < (IP_VS_CONN_TAB_SIZE>>5); idx++) {
 828                 unsigned hash = net_random() & IP_VS_CONN_TAB_MASK;
 829
 830                 /*
 831                  *  Lock is actually needed in this loop.
 832                  */
 833                 ct_write_lock_bh(hash);
 834
 835                 list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 836                         if (cp->flags & IP_VS_CONN_F_TEMPLATE)
 837                                 /* connection template */
 838                                 continue;
 839
 840                         if (cp->protocol == IPPROTO_TCP) {
 841                                 switch(cp->state) {
 842                                 case IP_VS_TCP_S_SYN_RECV:
 843                                 case IP_VS_TCP_S_SYNACK:
 844                                         break;
 845
 846                                 case IP_VS_TCP_S_ESTABLISHED:
 847                                         if (todrop_entry(cp))
 848                                                 break;
 849                                         continue;
 850
 851                                 default:
 852                                         continue;
 853                                 }
 854                         } else {
 855                                 if (!todrop_entry(cp))
 856                                         continue;
 857                         }
 858
 859                         IP_VS_DBG(4, "del connection\n");
 860                         ip_vs_conn_expire_now(cp);
 861                         if (cp->control) {
 862                                 IP_VS_DBG(4, "del conn template\n");
 863                                 ip_vs_conn_expire_now(cp->control);
 864                         }
 865                 }
 866                 ct_write_unlock_bh(hash);
 867         }
 868 }
 869
 870
 871 /*
 872  *      Flush all the connection entries in the ip_vs_conn_tab
 873  */
 874 static void ip_vs_conn_flush(void)
 875 {
 876         int idx;
 877         struct ip_vs_conn *cp;
 878
 879   flush_again:
 880         for (idx=0; idx<IP_VS_CONN_TAB_SIZE; idx++) {
 881                 /*
 882                  *  Lock is actually needed in this loop.
 883                  */
 884                 ct_write_lock_bh(idx);
 885
 886                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 887
 888                         IP_VS_DBG(4, "del connection\n");
 889                         ip_vs_conn_expire_now(cp);
 890                         if (cp->control) {
 891                                 IP_VS_DBG(4, "del conn template\n");
 892                                 ip_vs_conn_expire_now(cp->control);
 893                         }
 894                 }
 895                 ct_write_unlock_bh(idx);
 896         }
 897
 898         /* the counter may be not NULL, because maybe some conn entries
 899            are run by slow timer handler or unhashed but still referred */
 900         if (atomic_read(&ip_vs_conn_count) != 0) {
 901                 schedule();
 902                 goto flush_again;
 903         }
 904 }
 905
 906
 907 int ip_vs_conn_init(void)
 908 {
 909         int idx;
 910
 911         /*
 912          * Allocate the connection hash table and initialize its list heads
 913          */
 914         ip_vs_conn_tab = vmalloc(IP_VS_CONN_TAB_SIZE*sizeof(struct list_head));
 915         if (!ip_vs_conn_tab)
 916                 return -ENOMEM;
 917
 918         /* Allocate ip_vs_conn slab cache */
 919         ip_vs_conn_cachep = kmem_cache_create("ip_vs_conn",
 920                                               sizeof(struct ip_vs_conn), 0,
 921                                               SLAB_HWCACHE_ALIGN, NULL);
 922         if (!ip_vs_conn_cachep) {
 923                 vfree(ip_vs_conn_tab);
 924                 return -ENOMEM;
 925         }
 926
 927         IP_VS_INFO("Connection hash table configured "
 928                    "(size=%d, memory=%ldKbytes)\n",
 929                    IP_VS_CONN_TAB_SIZE,
 930                    (long)(IP_VS_CONN_TAB_SIZE*sizeof(struct list_head))/1024);
 931         IP_VS_DBG(0, "Each connection entry needs %Zd bytes at least\n",
 932                   sizeof(struct ip_vs_conn));
 933
 934         for (idx = 0; idx < IP_VS_CONN_TAB_SIZE; idx++) {
 935                 INIT_LIST_HEAD(&ip_vs_conn_tab[idx]);
 936         }
 937
 938         for (idx = 0; idx < CT_LOCKARRAY_SIZE; idx++)  {
 939                 rwlock_init(&__ip_vs_conntbl_lock_array[idx].l);
 940         }
 941
 942         proc_net_fops_create(&init_net, "ip_vs_conn", 0, &ip_vs_conn_fops);
 943
 944         /* calculate the random value for connection hash */
 945         get_random_bytes(&ip_vs_conn_rnd, sizeof(ip_vs_conn_rnd));
 946
 947         return 0;
 948 }
 949
 950
 951 void ip_vs_conn_cleanup(void)
 952 {
 953         /* flush all the connection entries first */
 954         ip_vs_conn_flush();
 955
 956         /* Release the empty cache */
 957         kmem_cache_destroy(ip_vs_conn_cachep);
 958         proc_net_remove(&init_net, "ip_vs_conn");
 959         vfree(ip_vs_conn_tab);
 960 }