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/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         if ((cp->flags & IP_VS_CONN_F_SYNC) &&
 397             (!(cp->flags & IP_VS_CONN_F_TEMPLATE)))
 398                 /* if the connection is not template and is created
 399                  * by sync, preserve the activity flag.
 400                  */
 401                 cp->flags |= atomic_read(&dest->conn_flags) &
 402                              (~IP_VS_CONN_F_INACTIVE);
 403         else
 404                 cp->flags |= atomic_read(&dest->conn_flags);
 405         cp->dest = dest;
 406
 407         IP_VS_DBG(7, "Bind-dest %s c:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
 408                   "d:%u.%u.%u.%u:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 409                   "dest->refcnt:%d\n",
 410                   ip_vs_proto_name(cp->protocol),
 411                   NIPQUAD(cp->caddr), ntohs(cp->cport),
 412                   NIPQUAD(cp->vaddr), ntohs(cp->vport),
 413                   NIPQUAD(cp->daddr), ntohs(cp->dport),
 414                   ip_vs_fwd_tag(cp), cp->state,
 415                   cp->flags, atomic_read(&cp->refcnt),
 416                   atomic_read(&dest->refcnt));
 417
 418         /* Update the connection counters */
 419         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
 420                 /* It is a normal connection, so increase the inactive
 421                    connection counter because it is in TCP SYNRECV
 422                    state (inactive) or other protocol inacive state */
 423                 if ((cp->flags & IP_VS_CONN_F_SYNC) &&
 424                     (!(cp->flags & IP_VS_CONN_F_INACTIVE)))
 425                         atomic_inc(&dest->activeconns);
 426                 else
 427                         atomic_inc(&dest->inactconns);
 428         } else {
 429                 /* It is a persistent connection/template, so increase
 430                    the peristent connection counter */
 431                 atomic_inc(&dest->persistconns);
 432         }
 433
 434         if (dest->u_threshold != 0 &&
 435             ip_vs_dest_totalconns(dest) >= dest->u_threshold)
 436                 dest->flags |= IP_VS_DEST_F_OVERLOAD;
 437 }
 438
 439
 440 /*
 441  * Check if there is a destination for the connection, if so
 442  * bind the connection to the destination.
 443  */
 444 struct ip_vs_dest *ip_vs_try_bind_dest(struct ip_vs_conn *cp)
 445 {
 446         struct ip_vs_dest *dest;
 447
 448         if ((cp) && (!cp->dest)) {
 449                 dest = ip_vs_find_dest(cp->daddr, cp->dport,
 450                                        cp->vaddr, cp->vport, cp->protocol);
 451                 ip_vs_bind_dest(cp, dest);
 452                 return dest;
 453         } else
 454                 return NULL;
 455 }
 456
 457
 458 /*
 459  *      Unbind a connection entry with its VS destination
 460  *      Called by the ip_vs_conn_expire function.
 461  */
 462 static inline void ip_vs_unbind_dest(struct ip_vs_conn *cp)
 463 {
 464         struct ip_vs_dest *dest = cp->dest;
 465
 466         if (!dest)
 467                 return;
 468
 469         IP_VS_DBG(7, "Unbind-dest %s c:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
 470                   "d:%u.%u.%u.%u:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 471                   "dest->refcnt:%d\n",
 472                   ip_vs_proto_name(cp->protocol),
 473                   NIPQUAD(cp->caddr), ntohs(cp->cport),
 474                   NIPQUAD(cp->vaddr), ntohs(cp->vport),
 475                   NIPQUAD(cp->daddr), ntohs(cp->dport),
 476                   ip_vs_fwd_tag(cp), cp->state,
 477                   cp->flags, atomic_read(&cp->refcnt),
 478                   atomic_read(&dest->refcnt));
 479
 480         /* Update the connection counters */
 481         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
 482                 /* It is a normal connection, so decrease the inactconns
 483                    or activeconns counter */
 484                 if (cp->flags & IP_VS_CONN_F_INACTIVE) {
 485                         atomic_dec(&dest->inactconns);
 486                 } else {
 487                         atomic_dec(&dest->activeconns);
 488                 }
 489         } else {
 490                 /* It is a persistent connection/template, so decrease
 491                    the peristent connection counter */
 492                 atomic_dec(&dest->persistconns);
 493         }
 494
 495         if (dest->l_threshold != 0) {
 496                 if (ip_vs_dest_totalconns(dest) < dest->l_threshold)
 497                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 498         } else if (dest->u_threshold != 0) {
 499                 if (ip_vs_dest_totalconns(dest) * 4 < dest->u_threshold * 3)
 500                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 501         } else {
 502                 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
 503                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 504         }
 505
 506         /*
 507          * Simply decrease the refcnt of the dest, because the
 508          * dest will be either in service's destination list
 509          * or in the trash.
 510          */
 511         atomic_dec(&dest->refcnt);
 512 }
 513
 514
 515 /*
 516  *      Checking if the destination of a connection template is available.
 517  *      If available, return 1, otherwise invalidate this connection
 518  *      template and return 0.
 519  */
 520 int ip_vs_check_template(struct ip_vs_conn *ct)
 521 {
 522         struct ip_vs_dest *dest = ct->dest;
 523
 524         /*
 525          * Checking the dest server status.
 526          */
 527         if ((dest == NULL) ||
 528             !(dest->flags & IP_VS_DEST_F_AVAILABLE) ||
 529             (sysctl_ip_vs_expire_quiescent_template &&
 530              (atomic_read(&dest->weight) == 0))) {
 531                 IP_VS_DBG(9, "check_template: dest not available for "
 532                           "protocol %s s:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
 533                           "-> d:%u.%u.%u.%u:%d\n",
 534                           ip_vs_proto_name(ct->protocol),
 535                           NIPQUAD(ct->caddr), ntohs(ct->cport),
 536                           NIPQUAD(ct->vaddr), ntohs(ct->vport),
 537                           NIPQUAD(ct->daddr), ntohs(ct->dport));
 538
 539                 /*
 540                  * Invalidate the connection template
 541                  */
 542                 if (ct->vport != htons(0xffff)) {
 543                         if (ip_vs_conn_unhash(ct)) {
 544                                 ct->dport = htons(0xffff);
 545                                 ct->vport = htons(0xffff);
 546                                 ct->cport = 0;
 547                                 ip_vs_conn_hash(ct);
 548                         }
 549                 }
 550
 551                 /*
 552                  * Simply decrease the refcnt of the template,
 553                  * don't restart its timer.
 554                  */
 555                 atomic_dec(&ct->refcnt);
 556                 return 0;
 557         }
 558         return 1;
 559 }
 560
 561 static void ip_vs_conn_expire(unsigned long data)
 562 {
 563         struct ip_vs_conn *cp = (struct ip_vs_conn *)data;
 564
 565         cp->timeout = 60*HZ;
 566
 567         /*
 568          *      hey, I'm using it
 569          */
 570         atomic_inc(&cp->refcnt);
 571
 572         /*
 573          *      do I control anybody?
 574          */
 575         if (atomic_read(&cp->n_control))
 576                 goto expire_later;
 577
 578         /*
 579          *      unhash it if it is hashed in the conn table
 580          */
 581         if (!ip_vs_conn_unhash(cp))
 582                 goto expire_later;
 583
 584         /*
 585          *      refcnt==1 implies I'm the only one referrer
 586          */
 587         if (likely(atomic_read(&cp->refcnt) == 1)) {
 588                 /* delete the timer if it is activated by other users */
 589                 if (timer_pending(&cp->timer))
 590                         del_timer(&cp->timer);
 591
 592                 /* does anybody control me? */
 593                 if (cp->control)
 594                         ip_vs_control_del(cp);
 595
 596                 if (unlikely(cp->app != NULL))
 597                         ip_vs_unbind_app(cp);
 598                 ip_vs_unbind_dest(cp);
 599                 if (cp->flags & IP_VS_CONN_F_NO_CPORT)
 600                         atomic_dec(&ip_vs_conn_no_cport_cnt);
 601                 atomic_dec(&ip_vs_conn_count);
 602
 603                 kmem_cache_free(ip_vs_conn_cachep, cp);
 604                 return;
 605         }
 606
 607         /* hash it back to the table */
 608         ip_vs_conn_hash(cp);
 609
 610   expire_later:
 611         IP_VS_DBG(7, "delayed: conn->refcnt-1=%d conn->n_control=%d\n",
 612                   atomic_read(&cp->refcnt)-1,
 613                   atomic_read(&cp->n_control));
 614
 615         ip_vs_conn_put(cp);
 616 }
 617
 618
 619 void ip_vs_conn_expire_now(struct ip_vs_conn *cp)
 620 {
 621         if (del_timer(&cp->timer))
 622                 mod_timer(&cp->timer, jiffies);
 623 }
 624
 625
 626 /*
 627  *      Create a new connection entry and hash it into the ip_vs_conn_tab
 628  */
 629 struct ip_vs_conn *
 630 ip_vs_conn_new(int proto, __be32 caddr, __be16 cport, __be32 vaddr, __be16 vport,
 631                __be32 daddr, __be16 dport, unsigned flags,
 632                struct ip_vs_dest *dest)
 633 {
 634         struct ip_vs_conn *cp;
 635         struct ip_vs_protocol *pp = ip_vs_proto_get(proto);
 636
 637         cp = kmem_cache_zalloc(ip_vs_conn_cachep, GFP_ATOMIC);
 638         if (cp == NULL) {
 639                 IP_VS_ERR_RL("ip_vs_conn_new: no memory available.\n");
 640                 return NULL;
 641         }
 642
 643         INIT_LIST_HEAD(&cp->c_list);
 644         setup_timer(&cp->timer, ip_vs_conn_expire, (unsigned long)cp);
 645         cp->protocol       = proto;
 646         cp->caddr          = caddr;
 647         cp->cport          = cport;
 648         cp->vaddr          = vaddr;
 649         cp->vport          = vport;
 650         cp->daddr          = daddr;
 651         cp->dport          = dport;
 652         cp->flags          = flags;
 653         spin_lock_init(&cp->lock);
 654
 655         /*
 656          * Set the entry is referenced by the current thread before hashing
 657          * it in the table, so that other thread run ip_vs_random_dropentry
 658          * but cannot drop this entry.
 659          */
 660         atomic_set(&cp->refcnt, 1);
 661
 662         atomic_set(&cp->n_control, 0);
 663         atomic_set(&cp->in_pkts, 0);
 664
 665         atomic_inc(&ip_vs_conn_count);
 666         if (flags & IP_VS_CONN_F_NO_CPORT)
 667                 atomic_inc(&ip_vs_conn_no_cport_cnt);
 668
 669         /* Bind the connection with a destination server */
 670         ip_vs_bind_dest(cp, dest);
 671
 672         /* Set its state and timeout */
 673         cp->state = 0;
 674         cp->timeout = 3*HZ;
 675
 676         /* Bind its packet transmitter */
 677         ip_vs_bind_xmit(cp);
 678
 679         if (unlikely(pp && atomic_read(&pp->appcnt)))
 680                 ip_vs_bind_app(cp, pp);
 681
 682         /* Hash it in the ip_vs_conn_tab finally */
 683         ip_vs_conn_hash(cp);
 684
 685         return cp;
 686 }
 687
 688
 689 /*
 690  *      /proc/net/ip_vs_conn entries
 691  */
 692 #ifdef CONFIG_PROC_FS
 693
 694 static void *ip_vs_conn_array(struct seq_file *seq, loff_t pos)
 695 {
 696         int idx;
 697         struct ip_vs_conn *cp;
 698
 699         for(idx = 0; idx < IP_VS_CONN_TAB_SIZE; idx++) {
 700                 ct_read_lock_bh(idx);
 701                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 702                         if (pos-- == 0) {
 703                                 seq->private = &ip_vs_conn_tab[idx];
 704                                 return cp;
 705                         }
 706                 }
 707                 ct_read_unlock_bh(idx);
 708         }
 709
 710         return NULL;
 711 }
 712
 713 static void *ip_vs_conn_seq_start(struct seq_file *seq, loff_t *pos)
 714 {
 715         seq->private = NULL;
 716         return *pos ? ip_vs_conn_array(seq, *pos - 1) :SEQ_START_TOKEN;
 717 }
 718
 719 static void *ip_vs_conn_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 720 {
 721         struct ip_vs_conn *cp = v;
 722         struct list_head *e, *l = seq->private;
 723         int idx;
 724
 725         ++*pos;
 726         if (v == SEQ_START_TOKEN)
 727                 return ip_vs_conn_array(seq, 0);
 728
 729         /* more on same hash chain? */
 730         if ((e = cp->c_list.next) != l)
 731                 return list_entry(e, struct ip_vs_conn, c_list);
 732
 733         idx = l - ip_vs_conn_tab;
 734         ct_read_unlock_bh(idx);
 735
 736         while (++idx < IP_VS_CONN_TAB_SIZE) {
 737                 ct_read_lock_bh(idx);
 738                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 739                         seq->private = &ip_vs_conn_tab[idx];
 740                         return cp;
 741                 }
 742                 ct_read_unlock_bh(idx);
 743         }
 744         seq->private = NULL;
 745         return NULL;
 746 }
 747
 748 static void ip_vs_conn_seq_stop(struct seq_file *seq, void *v)
 749 {
 750         struct list_head *l = seq->private;
 751
 752         if (l)
 753                 ct_read_unlock_bh(l - ip_vs_conn_tab);
 754 }
 755
 756 static int ip_vs_conn_seq_show(struct seq_file *seq, void *v)
 757 {
 758
 759         if (v == SEQ_START_TOKEN)
 760                 seq_puts(seq,
 761    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Expires\n");
 762         else {
 763                 const struct ip_vs_conn *cp = v;
 764
 765                 seq_printf(seq,
 766                         "%-3s %08X %04X %08X %04X %08X %04X %-11s %7lu\n",
 767                                 ip_vs_proto_name(cp->protocol),
 768                                 ntohl(cp->caddr), ntohs(cp->cport),
 769                                 ntohl(cp->vaddr), ntohs(cp->vport),
 770                                 ntohl(cp->daddr), ntohs(cp->dport),
 771                                 ip_vs_state_name(cp->protocol, cp->state),
 772                                 (cp->timer.expires-jiffies)/HZ);
 773         }
 774         return 0;
 775 }
 776
 777 static const struct seq_operations ip_vs_conn_seq_ops = {
 778         .start = ip_vs_conn_seq_start,
 779         .next  = ip_vs_conn_seq_next,
 780         .stop  = ip_vs_conn_seq_stop,
 781         .show  = ip_vs_conn_seq_show,
 782 };
 783
 784 static int ip_vs_conn_open(struct inode *inode, struct file *file)
 785 {
 786         return seq_open(file, &ip_vs_conn_seq_ops);
 787 }
 788
 789 static const struct file_operations ip_vs_conn_fops = {
 790         .owner   = THIS_MODULE,
 791         .open    = ip_vs_conn_open,
 792         .read    = seq_read,
 793         .llseek  = seq_lseek,
 794         .release = seq_release,
 795 };
 796
 797 static const char *ip_vs_origin_name(unsigned flags)
 798 {
 799         if (flags & IP_VS_CONN_F_SYNC)
 800                 return "SYNC";
 801         else
 802                 return "LOCAL";
 803 }
 804
 805 static int ip_vs_conn_sync_seq_show(struct seq_file *seq, void *v)
 806 {
 807
 808         if (v == SEQ_START_TOKEN)
 809                 seq_puts(seq,
 810    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Origin Expires\n");
 811         else {
 812                 const struct ip_vs_conn *cp = v;
 813
 814                 seq_printf(seq,
 815                         "%-3s %08X %04X %08X %04X %08X %04X %-11s %-6s %7lu\n",
 816                                 ip_vs_proto_name(cp->protocol),
 817                                 ntohl(cp->caddr), ntohs(cp->cport),
 818                                 ntohl(cp->vaddr), ntohs(cp->vport),
 819                                 ntohl(cp->daddr), ntohs(cp->dport),
 820                                 ip_vs_state_name(cp->protocol, cp->state),
 821                                 ip_vs_origin_name(cp->flags),
 822                                 (cp->timer.expires-jiffies)/HZ);
 823         }
 824         return 0;
 825 }
 826
 827 static const struct seq_operations ip_vs_conn_sync_seq_ops = {
 828         .start = ip_vs_conn_seq_start,
 829         .next  = ip_vs_conn_seq_next,
 830         .stop  = ip_vs_conn_seq_stop,
 831         .show  = ip_vs_conn_sync_seq_show,
 832 };
 833
 834 static int ip_vs_conn_sync_open(struct inode *inode, struct file *file)
 835 {
 836         return seq_open(file, &ip_vs_conn_sync_seq_ops);
 837 }
 838
 839 static const struct file_operations ip_vs_conn_sync_fops = {
 840         .owner   = THIS_MODULE,
 841         .open    = ip_vs_conn_sync_open,
 842         .read    = seq_read,
 843         .llseek  = seq_lseek,
 844         .release = seq_release,
 845 };
 846
 847 #endif
 848
 849
 850 /*
 851  *      Randomly drop connection entries before running out of memory
 852  */
 853 static inline int todrop_entry(struct ip_vs_conn *cp)
 854 {
 855         /*
 856          * The drop rate array needs tuning for real environments.
 857          * Called from timer bh only => no locking
 858          */
 859         static const char todrop_rate[9] = {0, 1, 2, 3, 4, 5, 6, 7, 8};
 860         static char todrop_counter[9] = {0};
 861         int i;
 862
 863         /* if the conn entry hasn't lasted for 60 seconds, don't drop it.
 864            This will leave enough time for normal connection to get
 865            through. */
 866         if (time_before(cp->timeout + jiffies, cp->timer.expires + 60*HZ))
 867                 return 0;
 868
 869         /* Don't drop the entry if its number of incoming packets is not
 870            located in [0, 8] */
 871         i = atomic_read(&cp->in_pkts);
 872         if (i > 8 || i < 0) return 0;
 873
 874         if (!todrop_rate[i]) return 0;
 875         if (--todrop_counter[i] > 0) return 0;
 876
 877         todrop_counter[i] = todrop_rate[i];
 878         return 1;
 879 }
 880
 881 /* Called from keventd and must protect itself from softirqs */
 882 void ip_vs_random_dropentry(void)
 883 {
 884         int idx;
 885         struct ip_vs_conn *cp;
 886
 887         /*
 888          * Randomly scan 1/32 of the whole table every second
 889          */
 890         for (idx = 0; idx < (IP_VS_CONN_TAB_SIZE>>5); idx++) {
 891                 unsigned hash = net_random() & IP_VS_CONN_TAB_MASK;
 892
 893                 /*
 894                  *  Lock is actually needed in this loop.
 895                  */
 896                 ct_write_lock_bh(hash);
 897
 898                 list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 899                         if (cp->flags & IP_VS_CONN_F_TEMPLATE)
 900                                 /* connection template */
 901                                 continue;
 902
 903                         if (cp->protocol == IPPROTO_TCP) {
 904                                 switch(cp->state) {
 905                                 case IP_VS_TCP_S_SYN_RECV:
 906                                 case IP_VS_TCP_S_SYNACK:
 907                                         break;
 908
 909                                 case IP_VS_TCP_S_ESTABLISHED:
 910                                         if (todrop_entry(cp))
 911                                                 break;
 912                                         continue;
 913
 914                                 default:
 915                                         continue;
 916                                 }
 917                         } else {
 918                                 if (!todrop_entry(cp))
 919                                         continue;
 920                         }
 921
 922                         IP_VS_DBG(4, "del connection\n");
 923                         ip_vs_conn_expire_now(cp);
 924                         if (cp->control) {
 925                                 IP_VS_DBG(4, "del conn template\n");
 926                                 ip_vs_conn_expire_now(cp->control);
 927                         }
 928                 }
 929                 ct_write_unlock_bh(hash);
 930         }
 931 }
 932
 933
 934 /*
 935  *      Flush all the connection entries in the ip_vs_conn_tab
 936  */
 937 static void ip_vs_conn_flush(void)
 938 {
 939         int idx;
 940         struct ip_vs_conn *cp;
 941
 942   flush_again:
 943         for (idx=0; idx<IP_VS_CONN_TAB_SIZE; idx++) {
 944                 /*
 945                  *  Lock is actually needed in this loop.
 946                  */
 947                 ct_write_lock_bh(idx);
 948
 949                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 950
 951                         IP_VS_DBG(4, "del connection\n");
 952                         ip_vs_conn_expire_now(cp);
 953                         if (cp->control) {
 954                                 IP_VS_DBG(4, "del conn template\n");
 955                                 ip_vs_conn_expire_now(cp->control);
 956                         }
 957                 }
 958                 ct_write_unlock_bh(idx);
 959         }
 960
 961         /* the counter may be not NULL, because maybe some conn entries
 962            are run by slow timer handler or unhashed but still referred */
 963         if (atomic_read(&ip_vs_conn_count) != 0) {
 964                 schedule();
 965                 goto flush_again;
 966         }
 967 }
 968
 969
 970 int ip_vs_conn_init(void)
 971 {
 972         int idx;
 973
 974         /*
 975          * Allocate the connection hash table and initialize its list heads
 976          */
 977         ip_vs_conn_tab = vmalloc(IP_VS_CONN_TAB_SIZE*sizeof(struct list_head));
 978         if (!ip_vs_conn_tab)
 979                 return -ENOMEM;
 980
 981         /* Allocate ip_vs_conn slab cache */
 982         ip_vs_conn_cachep = kmem_cache_create("ip_vs_conn",
 983                                               sizeof(struct ip_vs_conn), 0,
 984                                               SLAB_HWCACHE_ALIGN, NULL);
 985         if (!ip_vs_conn_cachep) {
 986                 vfree(ip_vs_conn_tab);
 987                 return -ENOMEM;
 988         }
 989
 990         IP_VS_INFO("Connection hash table configured "
 991                    "(size=%d, memory=%ldKbytes)\n",
 992                    IP_VS_CONN_TAB_SIZE,
 993                    (long)(IP_VS_CONN_TAB_SIZE*sizeof(struct list_head))/1024);
 994         IP_VS_DBG(0, "Each connection entry needs %Zd bytes at least\n",
 995                   sizeof(struct ip_vs_conn));
 996
 997         for (idx = 0; idx < IP_VS_CONN_TAB_SIZE; idx++) {
 998                 INIT_LIST_HEAD(&ip_vs_conn_tab[idx]);
 999         }
1000
1001         for (idx = 0; idx < CT_LOCKARRAY_SIZE; idx++)  {
1002                 rwlock_init(&__ip_vs_conntbl_lock_array[idx].l);
1003         }
1004
1005         proc_net_fops_create(&init_net, "ip_vs_conn", 0, &ip_vs_conn_fops);
1006         proc_net_fops_create(&init_net, "ip_vs_conn_sync", 0, &ip_vs_conn_sync_fops);
1007
1008         /* calculate the random value for connection hash */
1009         get_random_bytes(&ip_vs_conn_rnd, sizeof(ip_vs_conn_rnd));
1010
1011         return 0;
1012 }
1013
1014
1015 void ip_vs_conn_cleanup(void)
1016 {
1017         /* flush all the connection entries first */
1018         ip_vs_conn_flush();
1019
1020         /* Release the empty cache */
1021         kmem_cache_destroy(ip_vs_conn_cachep);
1022         proc_net_remove(&init_net, "ip_vs_conn");
1023         proc_net_remove(&init_net, "ip_vs_conn_sync");
1024         vfree(ip_vs_conn_tab);
1025 }