net/ipv4/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  * 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/in.h>
  28 #include <linux/net.h>
  29 #include <linux/kernel.h>
  30 #include <linux/module.h>
  31 #include <linux/vmalloc.h>
  32 #include <linux/proc_fs.h>              /* for proc_net_* */
  33 #include <linux/seq_file.h>
  34 #include <linux/jhash.h>
  35 #include <linux/random.h>
  36
  37 #include <net/ip_vs.h>
  38
  39
  40 /*
  41  *  Connection hash table: for input and output packets lookups of IPVS
  42  */
  43 static struct list_head *ip_vs_conn_tab;
  44
  45 /*  SLAB cache for IPVS connections */
  46 static kmem_cache_t *ip_vs_conn_cachep __read_mostly;
  47
  48 /*  counter for current IPVS connections */
  49 static atomic_t ip_vs_conn_count = ATOMIC_INIT(0);
  50
  51 /*  counter for no client port connections */
  52 static atomic_t ip_vs_conn_no_cport_cnt = ATOMIC_INIT(0);
  53
  54 /* random value for IPVS connection hash */
  55 static unsigned int ip_vs_conn_rnd;
  56
  57 /*
  58  *  Fine locking granularity for big connection hash table
  59  */
  60 #define CT_LOCKARRAY_BITS  4
  61 #define CT_LOCKARRAY_SIZE  (1<<CT_LOCKARRAY_BITS)
  62 #define CT_LOCKARRAY_MASK  (CT_LOCKARRAY_SIZE-1)
  63
  64 struct ip_vs_aligned_lock
  65 {
  66         rwlock_t        l;
  67 } __attribute__((__aligned__(SMP_CACHE_BYTES)));
  68
  69 /* lock array for conn table */
  70 static struct ip_vs_aligned_lock
  71 __ip_vs_conntbl_lock_array[CT_LOCKARRAY_SIZE] __cacheline_aligned;
  72
  73 static inline void ct_read_lock(unsigned key)
  74 {
  75         read_lock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  76 }
  77
  78 static inline void ct_read_unlock(unsigned key)
  79 {
  80         read_unlock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  81 }
  82
  83 static inline void ct_write_lock(unsigned key)
  84 {
  85         write_lock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  86 }
  87
  88 static inline void ct_write_unlock(unsigned key)
  89 {
  90         write_unlock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  91 }
  92
  93 static inline void ct_read_lock_bh(unsigned key)
  94 {
  95         read_lock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  96 }
  97
  98 static inline void ct_read_unlock_bh(unsigned key)
  99 {
 100         read_unlock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 101 }
 102
 103 static inline void ct_write_lock_bh(unsigned key)
 104 {
 105         write_lock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 106 }
 107
 108 static inline void ct_write_unlock_bh(unsigned key)
 109 {
 110         write_unlock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 111 }
 112
 113
 114 /*
 115  *      Returns hash value for IPVS connection entry
 116  */
 117 static unsigned int ip_vs_conn_hashkey(unsigned proto, __u32 addr, __u16 port)
 118 {
 119         return jhash_3words(addr, port, proto, ip_vs_conn_rnd)
 120                 & IP_VS_CONN_TAB_MASK;
 121 }
 122
 123
 124 /*
 125  *      Hashes ip_vs_conn in ip_vs_conn_tab by proto,addr,port.
 126  *      returns bool success.
 127  */
 128 static inline int ip_vs_conn_hash(struct ip_vs_conn *cp)
 129 {
 130         unsigned hash;
 131         int ret;
 132
 133         /* Hash by protocol, client address and port */
 134         hash = ip_vs_conn_hashkey(cp->protocol, cp->caddr, cp->cport);
 135
 136         ct_write_lock(hash);
 137
 138         if (!(cp->flags & IP_VS_CONN_F_HASHED)) {
 139                 list_add(&cp->c_list, &ip_vs_conn_tab[hash]);
 140                 cp->flags |= IP_VS_CONN_F_HASHED;
 141                 atomic_inc(&cp->refcnt);
 142                 ret = 1;
 143         } else {
 144                 IP_VS_ERR("ip_vs_conn_hash(): request for already hashed, "
 145                           "called from %p\n", __builtin_return_address(0));
 146                 ret = 0;
 147         }
 148
 149         ct_write_unlock(hash);
 150
 151         return ret;
 152 }
 153
 154
 155 /*
 156  *      UNhashes ip_vs_conn from ip_vs_conn_tab.
 157  *      returns bool success.
 158  */
 159 static inline int ip_vs_conn_unhash(struct ip_vs_conn *cp)
 160 {
 161         unsigned hash;
 162         int ret;
 163
 164         /* unhash it and decrease its reference counter */
 165         hash = ip_vs_conn_hashkey(cp->protocol, cp->caddr, cp->cport);
 166
 167         ct_write_lock(hash);
 168
 169         if (cp->flags & IP_VS_CONN_F_HASHED) {
 170                 list_del(&cp->c_list);
 171                 cp->flags &= ~IP_VS_CONN_F_HASHED;
 172                 atomic_dec(&cp->refcnt);
 173                 ret = 1;
 174         } else
 175                 ret = 0;
 176
 177         ct_write_unlock(hash);
 178
 179         return ret;
 180 }
 181
 182
 183 /*
 184  *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
 185  *  Called for pkts coming from OUTside-to-INside.
 186  *      s_addr, s_port: pkt source address (foreign host)
 187  *      d_addr, d_port: pkt dest address (load balancer)
 188  */
 189 static inline struct ip_vs_conn *__ip_vs_conn_in_get
 190 (int protocol, __u32 s_addr, __u16 s_port, __u32 d_addr, __u16 d_port)
 191 {
 192         unsigned hash;
 193         struct ip_vs_conn *cp;
 194
 195         hash = ip_vs_conn_hashkey(protocol, s_addr, s_port);
 196
 197         ct_read_lock(hash);
 198
 199         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 200                 if (s_addr==cp->caddr && s_port==cp->cport &&
 201                     d_port==cp->vport && d_addr==cp->vaddr &&
 202                     ((!s_port) ^ (!(cp->flags & IP_VS_CONN_F_NO_CPORT))) &&
 203                     protocol==cp->protocol) {
 204                         /* HIT */
 205                         atomic_inc(&cp->refcnt);
 206                         ct_read_unlock(hash);
 207                         return cp;
 208                 }
 209         }
 210
 211         ct_read_unlock(hash);
 212
 213         return NULL;
 214 }
 215
 216 struct ip_vs_conn *ip_vs_conn_in_get
 217 (int protocol, __u32 s_addr, __u16 s_port, __u32 d_addr, __u16 d_port)
 218 {
 219         struct ip_vs_conn *cp;
 220
 221         cp = __ip_vs_conn_in_get(protocol, s_addr, s_port, d_addr, d_port);
 222         if (!cp && atomic_read(&ip_vs_conn_no_cport_cnt))
 223                 cp = __ip_vs_conn_in_get(protocol, s_addr, 0, d_addr, d_port);
 224
 225         IP_VS_DBG(9, "lookup/in %s %u.%u.%u.%u:%d->%u.%u.%u.%u:%d %s\n",
 226                   ip_vs_proto_name(protocol),
 227                   NIPQUAD(s_addr), ntohs(s_port),
 228                   NIPQUAD(d_addr), ntohs(d_port),
 229                   cp?"hit":"not hit");
 230
 231         return cp;
 232 }
 233
 234 /* Get reference to connection template */
 235 struct ip_vs_conn *ip_vs_ct_in_get
 236 (int protocol, __u32 s_addr, __u16 s_port, __u32 d_addr, __u16 d_port)
 237 {
 238         unsigned hash;
 239         struct ip_vs_conn *cp;
 240
 241         hash = ip_vs_conn_hashkey(protocol, s_addr, s_port);
 242
 243         ct_read_lock(hash);
 244
 245         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 246                 if (s_addr==cp->caddr && s_port==cp->cport &&
 247                     d_port==cp->vport && d_addr==cp->vaddr &&
 248                     cp->flags & IP_VS_CONN_F_TEMPLATE &&
 249                     protocol==cp->protocol) {
 250                         /* HIT */
 251                         atomic_inc(&cp->refcnt);
 252                         goto out;
 253                 }
 254         }
 255         cp = NULL;
 256
 257   out:
 258         ct_read_unlock(hash);
 259
 260         IP_VS_DBG(9, "template lookup/in %s %u.%u.%u.%u:%d->%u.%u.%u.%u:%d %s\n",
 261                   ip_vs_proto_name(protocol),
 262                   NIPQUAD(s_addr), ntohs(s_port),
 263                   NIPQUAD(d_addr), ntohs(d_port),
 264                   cp?"hit":"not hit");
 265
 266         return cp;
 267 }
 268
 269 /*
 270  *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
 271  *  Called for pkts coming from inside-to-OUTside.
 272  *      s_addr, s_port: pkt source address (inside host)
 273  *      d_addr, d_port: pkt dest address (foreign host)
 274  */
 275 struct ip_vs_conn *ip_vs_conn_out_get
 276 (int protocol, __u32 s_addr, __u16 s_port, __u32 d_addr, __u16 d_port)
 277 {
 278         unsigned hash;
 279         struct ip_vs_conn *cp, *ret=NULL;
 280
 281         /*
 282          *      Check for "full" addressed entries
 283          */
 284         hash = ip_vs_conn_hashkey(protocol, d_addr, d_port);
 285
 286         ct_read_lock(hash);
 287
 288         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 289                 if (d_addr == cp->caddr && d_port == cp->cport &&
 290                     s_port == cp->dport && s_addr == cp->daddr &&
 291                     protocol == cp->protocol) {
 292                         /* HIT */
 293                         atomic_inc(&cp->refcnt);
 294                         ret = cp;
 295                         break;
 296                 }
 297         }
 298
 299         ct_read_unlock(hash);
 300
 301         IP_VS_DBG(9, "lookup/out %s %u.%u.%u.%u:%d->%u.%u.%u.%u:%d %s\n",
 302                   ip_vs_proto_name(protocol),
 303                   NIPQUAD(s_addr), ntohs(s_port),
 304                   NIPQUAD(d_addr), ntohs(d_port),
 305                   ret?"hit":"not hit");
 306
 307         return ret;
 308 }
 309
 310
 311 /*
 312  *      Put back the conn and restart its timer with its timeout
 313  */
 314 void ip_vs_conn_put(struct ip_vs_conn *cp)
 315 {
 316         /* reset it expire in its timeout */
 317         mod_timer(&cp->timer, jiffies+cp->timeout);
 318
 319         __ip_vs_conn_put(cp);
 320 }
 321
 322
 323 /*
 324  *      Fill a no_client_port connection with a client port number
 325  */
 326 void ip_vs_conn_fill_cport(struct ip_vs_conn *cp, __u16 cport)
 327 {
 328         if (ip_vs_conn_unhash(cp)) {
 329                 spin_lock(&cp->lock);
 330                 if (cp->flags & IP_VS_CONN_F_NO_CPORT) {
 331                         atomic_dec(&ip_vs_conn_no_cport_cnt);
 332                         cp->flags &= ~IP_VS_CONN_F_NO_CPORT;
 333                         cp->cport = cport;
 334                 }
 335                 spin_unlock(&cp->lock);
 336
 337                 /* hash on new dport */
 338                 ip_vs_conn_hash(cp);
 339         }
 340 }
 341
 342
 343 /*
 344  *      Bind a connection entry with the corresponding packet_xmit.
 345  *      Called by ip_vs_conn_new.
 346  */
 347 static inline void ip_vs_bind_xmit(struct ip_vs_conn *cp)
 348 {
 349         switch (IP_VS_FWD_METHOD(cp)) {
 350         case IP_VS_CONN_F_MASQ:
 351                 cp->packet_xmit = ip_vs_nat_xmit;
 352                 break;
 353
 354         case IP_VS_CONN_F_TUNNEL:
 355                 cp->packet_xmit = ip_vs_tunnel_xmit;
 356                 break;
 357
 358         case IP_VS_CONN_F_DROUTE:
 359                 cp->packet_xmit = ip_vs_dr_xmit;
 360                 break;
 361
 362         case IP_VS_CONN_F_LOCALNODE:
 363                 cp->packet_xmit = ip_vs_null_xmit;
 364                 break;
 365
 366         case IP_VS_CONN_F_BYPASS:
 367                 cp->packet_xmit = ip_vs_bypass_xmit;
 368                 break;
 369         }
 370 }
 371
 372
 373 static inline int ip_vs_dest_totalconns(struct ip_vs_dest *dest)
 374 {
 375         return atomic_read(&dest->activeconns)
 376                 + atomic_read(&dest->inactconns);
 377 }
 378
 379 /*
 380  *      Bind a connection entry with a virtual service destination
 381  *      Called just after a new connection entry is created.
 382  */
 383 static inline void
 384 ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest *dest)
 385 {
 386         /* if dest is NULL, then return directly */
 387         if (!dest)
 388                 return;
 389
 390         /* Increase the refcnt counter of the dest */
 391         atomic_inc(&dest->refcnt);
 392
 393         /* Bind with the destination and its corresponding transmitter */
 394         cp->flags |= atomic_read(&dest->conn_flags);
 395         cp->dest = dest;
 396
 397         IP_VS_DBG(7, "Bind-dest %s c:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
 398                   "d:%u.%u.%u.%u:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 399                   "dest->refcnt:%d\n",
 400                   ip_vs_proto_name(cp->protocol),
 401                   NIPQUAD(cp->caddr), ntohs(cp->cport),
 402                   NIPQUAD(cp->vaddr), ntohs(cp->vport),
 403                   NIPQUAD(cp->daddr), ntohs(cp->dport),
 404                   ip_vs_fwd_tag(cp), cp->state,
 405                   cp->flags, atomic_read(&cp->refcnt),
 406                   atomic_read(&dest->refcnt));
 407
 408         /* Update the connection counters */
 409         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
 410                 /* It is a normal connection, so increase the inactive
 411                    connection counter because it is in TCP SYNRECV
 412                    state (inactive) or other protocol inacive state */
 413                 atomic_inc(&dest->inactconns);
 414         } else {
 415                 /* It is a persistent connection/template, so increase
 416                    the peristent connection counter */
 417                 atomic_inc(&dest->persistconns);
 418         }
 419
 420         if (dest->u_threshold != 0 &&
 421             ip_vs_dest_totalconns(dest) >= dest->u_threshold)
 422                 dest->flags |= IP_VS_DEST_F_OVERLOAD;
 423 }
 424
 425
 426 /*
 427  *      Unbind a connection entry with its VS destination
 428  *      Called by the ip_vs_conn_expire function.
 429  */
 430 static inline void ip_vs_unbind_dest(struct ip_vs_conn *cp)
 431 {
 432         struct ip_vs_dest *dest = cp->dest;
 433
 434         if (!dest)
 435                 return;
 436
 437         IP_VS_DBG(7, "Unbind-dest %s c:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
 438                   "d:%u.%u.%u.%u:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 439                   "dest->refcnt:%d\n",
 440                   ip_vs_proto_name(cp->protocol),
 441                   NIPQUAD(cp->caddr), ntohs(cp->cport),
 442                   NIPQUAD(cp->vaddr), ntohs(cp->vport),
 443                   NIPQUAD(cp->daddr), ntohs(cp->dport),
 444                   ip_vs_fwd_tag(cp), cp->state,
 445                   cp->flags, atomic_read(&cp->refcnt),
 446                   atomic_read(&dest->refcnt));
 447
 448         /* Update the connection counters */
 449         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
 450                 /* It is a normal connection, so decrease the inactconns
 451                    or activeconns counter */
 452                 if (cp->flags & IP_VS_CONN_F_INACTIVE) {
 453                         atomic_dec(&dest->inactconns);
 454                 } else {
 455                         atomic_dec(&dest->activeconns);
 456                 }
 457         } else {
 458                 /* It is a persistent connection/template, so decrease
 459                    the peristent connection counter */
 460                 atomic_dec(&dest->persistconns);
 461         }
 462
 463         if (dest->l_threshold != 0) {
 464                 if (ip_vs_dest_totalconns(dest) < dest->l_threshold)
 465                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 466         } else if (dest->u_threshold != 0) {
 467                 if (ip_vs_dest_totalconns(dest) * 4 < dest->u_threshold * 3)
 468                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 469         } else {
 470                 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
 471                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 472         }
 473
 474         /*
 475          * Simply decrease the refcnt of the dest, because the
 476          * dest will be either in service's destination list
 477          * or in the trash.
 478          */
 479         atomic_dec(&dest->refcnt);
 480 }
 481
 482
 483 /*
 484  *      Checking if the destination of a connection template is available.
 485  *      If available, return 1, otherwise invalidate this connection
 486  *      template and return 0.
 487  */
 488 int ip_vs_check_template(struct ip_vs_conn *ct)
 489 {
 490         struct ip_vs_dest *dest = ct->dest;
 491
 492         /*
 493          * Checking the dest server status.
 494          */
 495         if ((dest == NULL) ||
 496             !(dest->flags & IP_VS_DEST_F_AVAILABLE) ||
 497             (sysctl_ip_vs_expire_quiescent_template &&
 498              (atomic_read(&dest->weight) == 0))) {
 499                 IP_VS_DBG(9, "check_template: dest not available for "
 500                           "protocol %s s:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
 501                           "-> d:%u.%u.%u.%u:%d\n",
 502                           ip_vs_proto_name(ct->protocol),
 503                           NIPQUAD(ct->caddr), ntohs(ct->cport),
 504                           NIPQUAD(ct->vaddr), ntohs(ct->vport),
 505                           NIPQUAD(ct->daddr), ntohs(ct->dport));
 506
 507                 /*
 508                  * Invalidate the connection template
 509                  */
 510                 if (ct->vport != 65535) {
 511                         if (ip_vs_conn_unhash(ct)) {
 512                                 ct->dport = 65535;
 513                                 ct->vport = 65535;
 514                                 ct->cport = 0;
 515                                 ip_vs_conn_hash(ct);
 516                         }
 517                 }
 518
 519                 /*
 520                  * Simply decrease the refcnt of the template,
 521                  * don't restart its timer.
 522                  */
 523                 atomic_dec(&ct->refcnt);
 524                 return 0;
 525         }
 526         return 1;
 527 }
 528
 529 static void ip_vs_conn_expire(unsigned long data)
 530 {
 531         struct ip_vs_conn *cp = (struct ip_vs_conn *)data;
 532
 533         cp->timeout = 60*HZ;
 534
 535         /*
 536          *      hey, I'm using it
 537          */
 538         atomic_inc(&cp->refcnt);
 539
 540         /*
 541          *      do I control anybody?
 542          */
 543         if (atomic_read(&cp->n_control))
 544                 goto expire_later;
 545
 546         /*
 547          *      unhash it if it is hashed in the conn table
 548          */
 549         if (!ip_vs_conn_unhash(cp))
 550                 goto expire_later;
 551
 552         /*
 553          *      refcnt==1 implies I'm the only one referrer
 554          */
 555         if (likely(atomic_read(&cp->refcnt) == 1)) {
 556                 /* delete the timer if it is activated by other users */
 557                 if (timer_pending(&cp->timer))
 558                         del_timer(&cp->timer);
 559
 560                 /* does anybody control me? */
 561                 if (cp->control)
 562                         ip_vs_control_del(cp);
 563
 564                 if (unlikely(cp->app != NULL))
 565                         ip_vs_unbind_app(cp);
 566                 ip_vs_unbind_dest(cp);
 567                 if (cp->flags & IP_VS_CONN_F_NO_CPORT)
 568                         atomic_dec(&ip_vs_conn_no_cport_cnt);
 569                 atomic_dec(&ip_vs_conn_count);
 570
 571                 kmem_cache_free(ip_vs_conn_cachep, cp);
 572                 return;
 573         }
 574
 575         /* hash it back to the table */
 576         ip_vs_conn_hash(cp);
 577
 578   expire_later:
 579         IP_VS_DBG(7, "delayed: conn->refcnt-1=%d conn->n_control=%d\n",
 580                   atomic_read(&cp->refcnt)-1,
 581                   atomic_read(&cp->n_control));
 582
 583         ip_vs_conn_put(cp);
 584 }
 585
 586
 587 void ip_vs_conn_expire_now(struct ip_vs_conn *cp)
 588 {
 589         if (del_timer(&cp->timer))
 590                 mod_timer(&cp->timer, jiffies);
 591 }
 592
 593
 594 /*
 595  *      Create a new connection entry and hash it into the ip_vs_conn_tab
 596  */
 597 struct ip_vs_conn *
 598 ip_vs_conn_new(int proto, __u32 caddr, __u16 cport, __u32 vaddr, __u16 vport,
 599                __u32 daddr, __u16 dport, unsigned flags,
 600                struct ip_vs_dest *dest)
 601 {
 602         struct ip_vs_conn *cp;
 603         struct ip_vs_protocol *pp = ip_vs_proto_get(proto);
 604
 605         cp = kmem_cache_alloc(ip_vs_conn_cachep, GFP_ATOMIC);
 606         if (cp == NULL) {
 607                 IP_VS_ERR_RL("ip_vs_conn_new: no memory available.\n");
 608                 return NULL;
 609         }
 610
 611         memset(cp, 0, sizeof(*cp));
 612         INIT_LIST_HEAD(&cp->c_list);
 613         init_timer(&cp->timer);
 614         cp->timer.data     = (unsigned long)cp;
 615         cp->timer.function = ip_vs_conn_expire;
 616         cp->protocol       = proto;
 617         cp->caddr          = caddr;
 618         cp->cport          = cport;
 619         cp->vaddr          = vaddr;
 620         cp->vport          = vport;
 621         cp->daddr          = daddr;
 622         cp->dport          = dport;
 623         cp->flags          = flags;
 624         spin_lock_init(&cp->lock);
 625
 626         /*
 627          * Set the entry is referenced by the current thread before hashing
 628          * it in the table, so that other thread run ip_vs_random_dropentry
 629          * but cannot drop this entry.
 630          */
 631         atomic_set(&cp->refcnt, 1);
 632
 633         atomic_set(&cp->n_control, 0);
 634         atomic_set(&cp->in_pkts, 0);
 635
 636         atomic_inc(&ip_vs_conn_count);
 637         if (flags & IP_VS_CONN_F_NO_CPORT)
 638                 atomic_inc(&ip_vs_conn_no_cport_cnt);
 639
 640         /* Bind the connection with a destination server */
 641         ip_vs_bind_dest(cp, dest);
 642
 643         /* Set its state and timeout */
 644         cp->state = 0;
 645         cp->timeout = 3*HZ;
 646
 647         /* Bind its packet transmitter */
 648         ip_vs_bind_xmit(cp);
 649
 650         if (unlikely(pp && atomic_read(&pp->appcnt)))
 651                 ip_vs_bind_app(cp, pp);
 652
 653         /* Hash it in the ip_vs_conn_tab finally */
 654         ip_vs_conn_hash(cp);
 655
 656         return cp;
 657 }
 658
 659
 660 /*
 661  *      /proc/net/ip_vs_conn entries
 662  */
 663 #ifdef CONFIG_PROC_FS
 664
 665 static void *ip_vs_conn_array(struct seq_file *seq, loff_t pos)
 666 {
 667         int idx;
 668         struct ip_vs_conn *cp;
 669
 670         for(idx = 0; idx < IP_VS_CONN_TAB_SIZE; idx++) {
 671                 ct_read_lock_bh(idx);
 672                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 673                         if (pos-- == 0) {
 674                                 seq->private = &ip_vs_conn_tab[idx];
 675                                 return cp;
 676                         }
 677                 }
 678                 ct_read_unlock_bh(idx);
 679         }
 680
 681         return NULL;
 682 }
 683
 684 static void *ip_vs_conn_seq_start(struct seq_file *seq, loff_t *pos)
 685 {
 686         seq->private = NULL;
 687         return *pos ? ip_vs_conn_array(seq, *pos - 1) :SEQ_START_TOKEN;
 688 }
 689
 690 static void *ip_vs_conn_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 691 {
 692         struct ip_vs_conn *cp = v;
 693         struct list_head *e, *l = seq->private;
 694         int idx;
 695
 696         ++*pos;
 697         if (v == SEQ_START_TOKEN)
 698                 return ip_vs_conn_array(seq, 0);
 699
 700         /* more on same hash chain? */
 701         if ((e = cp->c_list.next) != l)
 702                 return list_entry(e, struct ip_vs_conn, c_list);
 703
 704         idx = l - ip_vs_conn_tab;
 705         ct_read_unlock_bh(idx);
 706
 707         while (++idx < IP_VS_CONN_TAB_SIZE) {
 708                 ct_read_lock_bh(idx);
 709                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 710                         seq->private = &ip_vs_conn_tab[idx];
 711                         return cp;
 712                 }
 713                 ct_read_unlock_bh(idx);
 714         }
 715         seq->private = NULL;
 716         return NULL;
 717 }
 718
 719 static void ip_vs_conn_seq_stop(struct seq_file *seq, void *v)
 720 {
 721         struct list_head *l = seq->private;
 722
 723         if (l)
 724                 ct_read_unlock_bh(l - ip_vs_conn_tab);
 725 }
 726
 727 static int ip_vs_conn_seq_show(struct seq_file *seq, void *v)
 728 {
 729
 730         if (v == SEQ_START_TOKEN)
 731                 seq_puts(seq,
 732    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Expires\n");
 733         else {
 734                 const struct ip_vs_conn *cp = v;
 735
 736                 seq_printf(seq,
 737                         "%-3s %08X %04X %08X %04X %08X %04X %-11s %7lu\n",
 738                                 ip_vs_proto_name(cp->protocol),
 739                                 ntohl(cp->caddr), ntohs(cp->cport),
 740                                 ntohl(cp->vaddr), ntohs(cp->vport),
 741                                 ntohl(cp->daddr), ntohs(cp->dport),
 742                                 ip_vs_state_name(cp->protocol, cp->state),
 743                                 (cp->timer.expires-jiffies)/HZ);
 744         }
 745         return 0;
 746 }
 747
 748 static struct seq_operations ip_vs_conn_seq_ops = {
 749         .start = ip_vs_conn_seq_start,
 750         .next  = ip_vs_conn_seq_next,
 751         .stop  = ip_vs_conn_seq_stop,
 752         .show  = ip_vs_conn_seq_show,
 753 };
 754
 755 static int ip_vs_conn_open(struct inode *inode, struct file *file)
 756 {
 757         return seq_open(file, &ip_vs_conn_seq_ops);
 758 }
 759
 760 static struct file_operations ip_vs_conn_fops = {
 761         .owner   = THIS_MODULE,
 762         .open    = ip_vs_conn_open,
 763         .read    = seq_read,
 764         .llseek  = seq_lseek,
 765         .release = seq_release,
 766 };
 767 #endif
 768
 769
 770 /*
 771  *      Randomly drop connection entries before running out of memory
 772  */
 773 static inline int todrop_entry(struct ip_vs_conn *cp)
 774 {
 775         /*
 776          * The drop rate array needs tuning for real environments.
 777          * Called from timer bh only => no locking
 778          */
 779         static const char todrop_rate[9] = {0, 1, 2, 3, 4, 5, 6, 7, 8};
 780         static char todrop_counter[9] = {0};
 781         int i;
 782
 783         /* if the conn entry hasn't lasted for 60 seconds, don't drop it.
 784            This will leave enough time for normal connection to get
 785            through. */
 786         if (time_before(cp->timeout + jiffies, cp->timer.expires + 60*HZ))
 787                 return 0;
 788
 789         /* Don't drop the entry if its number of incoming packets is not
 790            located in [0, 8] */
 791         i = atomic_read(&cp->in_pkts);
 792         if (i > 8 || i < 0) return 0;
 793
 794         if (!todrop_rate[i]) return 0;
 795         if (--todrop_counter[i] > 0) return 0;
 796
 797         todrop_counter[i] = todrop_rate[i];
 798         return 1;
 799 }
 800
 801 /* Called from keventd and must protect itself from softirqs */
 802 void ip_vs_random_dropentry(void)
 803 {
 804         int idx;
 805         struct ip_vs_conn *cp;
 806
 807         /*
 808          * Randomly scan 1/32 of the whole table every second
 809          */
 810         for (idx = 0; idx < (IP_VS_CONN_TAB_SIZE>>5); idx++) {
 811                 unsigned hash = net_random() & IP_VS_CONN_TAB_MASK;
 812
 813                 /*
 814                  *  Lock is actually needed in this loop.
 815                  */
 816                 ct_write_lock_bh(hash);
 817
 818                 list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 819                         if (cp->flags & IP_VS_CONN_F_TEMPLATE)
 820                                 /* connection template */
 821                                 continue;
 822
 823                         if (cp->protocol == IPPROTO_TCP) {
 824                                 switch(cp->state) {
 825                                 case IP_VS_TCP_S_SYN_RECV:
 826                                 case IP_VS_TCP_S_SYNACK:
 827                                         break;
 828
 829                                 case IP_VS_TCP_S_ESTABLISHED:
 830                                         if (todrop_entry(cp))
 831                                                 break;
 832                                         continue;
 833
 834                                 default:
 835                                         continue;
 836                                 }
 837                         } else {
 838                                 if (!todrop_entry(cp))
 839                                         continue;
 840                         }
 841
 842                         IP_VS_DBG(4, "del connection\n");
 843                         ip_vs_conn_expire_now(cp);
 844                         if (cp->control) {
 845                                 IP_VS_DBG(4, "del conn template\n");
 846                                 ip_vs_conn_expire_now(cp->control);
 847                         }
 848                 }
 849                 ct_write_unlock_bh(hash);
 850         }
 851 }
 852
 853
 854 /*
 855  *      Flush all the connection entries in the ip_vs_conn_tab
 856  */
 857 static void ip_vs_conn_flush(void)
 858 {
 859         int idx;
 860         struct ip_vs_conn *cp;
 861
 862   flush_again:
 863         for (idx=0; idx<IP_VS_CONN_TAB_SIZE; idx++) {
 864                 /*
 865                  *  Lock is actually needed in this loop.
 866                  */
 867                 ct_write_lock_bh(idx);
 868
 869                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 870
 871                         IP_VS_DBG(4, "del connection\n");
 872                         ip_vs_conn_expire_now(cp);
 873                         if (cp->control) {
 874                                 IP_VS_DBG(4, "del conn template\n");
 875                                 ip_vs_conn_expire_now(cp->control);
 876                         }
 877                 }
 878                 ct_write_unlock_bh(idx);
 879         }
 880
 881         /* the counter may be not NULL, because maybe some conn entries
 882            are run by slow timer handler or unhashed but still referred */
 883         if (atomic_read(&ip_vs_conn_count) != 0) {
 884                 schedule();
 885                 goto flush_again;
 886         }
 887 }
 888
 889
 890 int ip_vs_conn_init(void)
 891 {
 892         int idx;
 893
 894         /*
 895          * Allocate the connection hash table and initialize its list heads
 896          */
 897         ip_vs_conn_tab = vmalloc(IP_VS_CONN_TAB_SIZE*sizeof(struct list_head));
 898         if (!ip_vs_conn_tab)
 899                 return -ENOMEM;
 900
 901         /* Allocate ip_vs_conn slab cache */
 902         ip_vs_conn_cachep = kmem_cache_create("ip_vs_conn",
 903                                               sizeof(struct ip_vs_conn), 0,
 904                                               SLAB_HWCACHE_ALIGN, NULL, NULL);
 905         if (!ip_vs_conn_cachep) {
 906                 vfree(ip_vs_conn_tab);
 907                 return -ENOMEM;
 908         }
 909
 910         IP_VS_INFO("Connection hash table configured "
 911                    "(size=%d, memory=%ldKbytes)\n",
 912                    IP_VS_CONN_TAB_SIZE,
 913                    (long)(IP_VS_CONN_TAB_SIZE*sizeof(struct list_head))/1024);
 914         IP_VS_DBG(0, "Each connection entry needs %Zd bytes at least\n",
 915                   sizeof(struct ip_vs_conn));
 916
 917         for (idx = 0; idx < IP_VS_CONN_TAB_SIZE; idx++) {
 918                 INIT_LIST_HEAD(&ip_vs_conn_tab[idx]);
 919         }
 920
 921         for (idx = 0; idx < CT_LOCKARRAY_SIZE; idx++)  {
 922                 rwlock_init(&__ip_vs_conntbl_lock_array[idx].l);
 923         }
 924
 925         proc_net_fops_create("ip_vs_conn", 0, &ip_vs_conn_fops);
 926
 927         /* calculate the random value for connection hash */
 928         get_random_bytes(&ip_vs_conn_rnd, sizeof(ip_vs_conn_rnd));
 929
 930         return 0;
 931 }
 932
 933
 934 void ip_vs_conn_cleanup(void)
 935 {
 936         /* flush all the connection entries first */
 937         ip_vs_conn_flush();
 938
 939         /* Release the empty cache */
 940         kmem_cache_destroy(ip_vs_conn_cachep);
 941         proc_net_remove("ip_vs_conn");
 942         vfree(ip_vs_conn_tab);
 943 }