SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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  * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
   9  *              Peter Kese <peter.kese@ijs.si>
  10  *              Julian Anastasov <ja@ssi.bg>
  11  *
  12  *              This program is free software; you can redistribute it and/or
  13  *              modify it under the terms of the GNU General Public License
  14  *              as published by the Free Software Foundation; either version
  15  *              2 of the License, or (at your option) any later version.
  16  *
  17  * The IPVS code for kernel 2.2 was done by Wensong Zhang and Peter Kese,
  18  * with changes/fixes from Julian Anastasov, Lars Marowsky-Bree, Horms
  19  * and others. Many code here is taken from IP MASQ code of kernel 2.2.
  20  *
  21  * Changes:
  22  *
  23  */
  24
  25 #include <linux/interrupt.h>
  26 #include <linux/in.h>
  27 #include <linux/net.h>
  28 #include <linux/kernel.h>
  29 #include <linux/module.h>
  30 #include <linux/vmalloc.h>
  31 #include <linux/proc_fs.h>              /* for proc_net_* */
  32 #include <linux/seq_file.h>
  33 #include <linux/jhash.h>
  34 #include <linux/random.h>
  35
  36 #include <net/net_namespace.h>
  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 struct kmem_cache *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, __be32 addr, __be16 port)
 118 {
 119         return jhash_3words((__force u32)addr, (__force u32)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, __be32 s_addr, __be16 s_port, __be32 d_addr, __be16 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, __be32 s_addr, __be16 s_port, __be32 d_addr, __be16 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, __be32 s_addr, __be16 s_port, __be32 d_addr, __be16 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, __be32 s_addr, __be16 s_port, __be32 d_addr, __be16 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, __be16 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         if ((cp->flags & IP_VS_CONN_F_SYNC) &&
 395             (!(cp->flags & IP_VS_CONN_F_TEMPLATE)))
 396                 /* if the connection is not template and is created
 397                  * by sync, preserve the activity flag.
 398                  */
 399                 cp->flags |= atomic_read(&dest->conn_flags) &
 400                              (~IP_VS_CONN_F_INACTIVE);
 401         else
 402                 cp->flags |= atomic_read(&dest->conn_flags);
 403         cp->dest = dest;
 404
 405         IP_VS_DBG(7, "Bind-dest %s c:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
 406                   "d:%u.%u.%u.%u:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 407                   "dest->refcnt:%d\n",
 408                   ip_vs_proto_name(cp->protocol),
 409                   NIPQUAD(cp->caddr), ntohs(cp->cport),
 410                   NIPQUAD(cp->vaddr), ntohs(cp->vport),
 411                   NIPQUAD(cp->daddr), ntohs(cp->dport),
 412                   ip_vs_fwd_tag(cp), cp->state,
 413                   cp->flags, atomic_read(&cp->refcnt),
 414                   atomic_read(&dest->refcnt));
 415
 416         /* Update the connection counters */
 417         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
 418                 /* It is a normal connection, so increase the inactive
 419                    connection counter because it is in TCP SYNRECV
 420                    state (inactive) or other protocol inacive state */
 421                 if ((cp->flags & IP_VS_CONN_F_SYNC) &&
 422                     (!(cp->flags & IP_VS_CONN_F_INACTIVE)))
 423                         atomic_inc(&dest->activeconns);
 424                 else
 425                         atomic_inc(&dest->inactconns);
 426         } else {
 427                 /* It is a persistent connection/template, so increase
 428                    the peristent connection counter */
 429                 atomic_inc(&dest->persistconns);
 430         }
 431
 432         if (dest->u_threshold != 0 &&
 433             ip_vs_dest_totalconns(dest) >= dest->u_threshold)
 434                 dest->flags |= IP_VS_DEST_F_OVERLOAD;
 435 }
 436
 437
 438 /*
 439  * Check if there is a destination for the connection, if so
 440  * bind the connection to the destination.
 441  */
 442 struct ip_vs_dest *ip_vs_try_bind_dest(struct ip_vs_conn *cp)
 443 {
 444         struct ip_vs_dest *dest;
 445
 446         if ((cp) && (!cp->dest)) {
 447                 dest = ip_vs_find_dest(cp->daddr, cp->dport,
 448                                        cp->vaddr, cp->vport, cp->protocol);
 449                 ip_vs_bind_dest(cp, dest);
 450                 return dest;
 451         } else
 452                 return NULL;
 453 }
 454
 455
 456 /*
 457  *      Unbind a connection entry with its VS destination
 458  *      Called by the ip_vs_conn_expire function.
 459  */
 460 static inline void ip_vs_unbind_dest(struct ip_vs_conn *cp)
 461 {
 462         struct ip_vs_dest *dest = cp->dest;
 463
 464         if (!dest)
 465                 return;
 466
 467         IP_VS_DBG(7, "Unbind-dest %s c:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
 468                   "d:%u.%u.%u.%u:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 469                   "dest->refcnt:%d\n",
 470                   ip_vs_proto_name(cp->protocol),
 471                   NIPQUAD(cp->caddr), ntohs(cp->cport),
 472                   NIPQUAD(cp->vaddr), ntohs(cp->vport),
 473                   NIPQUAD(cp->daddr), ntohs(cp->dport),
 474                   ip_vs_fwd_tag(cp), cp->state,
 475                   cp->flags, atomic_read(&cp->refcnt),
 476                   atomic_read(&dest->refcnt));
 477
 478         /* Update the connection counters */
 479         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
 480                 /* It is a normal connection, so decrease the inactconns
 481                    or activeconns counter */
 482                 if (cp->flags & IP_VS_CONN_F_INACTIVE) {
 483                         atomic_dec(&dest->inactconns);
 484                 } else {
 485                         atomic_dec(&dest->activeconns);
 486                 }
 487         } else {
 488                 /* It is a persistent connection/template, so decrease
 489                    the peristent connection counter */
 490                 atomic_dec(&dest->persistconns);
 491         }
 492
 493         if (dest->l_threshold != 0) {
 494                 if (ip_vs_dest_totalconns(dest) < dest->l_threshold)
 495                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 496         } else if (dest->u_threshold != 0) {
 497                 if (ip_vs_dest_totalconns(dest) * 4 < dest->u_threshold * 3)
 498                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 499         } else {
 500                 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
 501                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 502         }
 503
 504         /*
 505          * Simply decrease the refcnt of the dest, because the
 506          * dest will be either in service's destination list
 507          * or in the trash.
 508          */
 509         atomic_dec(&dest->refcnt);
 510 }
 511
 512
 513 /*
 514  *      Checking if the destination of a connection template is available.
 515  *      If available, return 1, otherwise invalidate this connection
 516  *      template and return 0.
 517  */
 518 int ip_vs_check_template(struct ip_vs_conn *ct)
 519 {
 520         struct ip_vs_dest *dest = ct->dest;
 521
 522         /*
 523          * Checking the dest server status.
 524          */
 525         if ((dest == NULL) ||
 526             !(dest->flags & IP_VS_DEST_F_AVAILABLE) ||
 527             (sysctl_ip_vs_expire_quiescent_template &&
 528              (atomic_read(&dest->weight) == 0))) {
 529                 IP_VS_DBG(9, "check_template: dest not available for "
 530                           "protocol %s s:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
 531                           "-> d:%u.%u.%u.%u:%d\n",
 532                           ip_vs_proto_name(ct->protocol),
 533                           NIPQUAD(ct->caddr), ntohs(ct->cport),
 534                           NIPQUAD(ct->vaddr), ntohs(ct->vport),
 535                           NIPQUAD(ct->daddr), ntohs(ct->dport));
 536
 537                 /*
 538                  * Invalidate the connection template
 539                  */
 540                 if (ct->vport != htons(0xffff)) {
 541                         if (ip_vs_conn_unhash(ct)) {
 542                                 ct->dport = htons(0xffff);
 543                                 ct->vport = htons(0xffff);
 544                                 ct->cport = 0;
 545                                 ip_vs_conn_hash(ct);
 546                         }
 547                 }
 548
 549                 /*
 550                  * Simply decrease the refcnt of the template,
 551                  * don't restart its timer.
 552                  */
 553                 atomic_dec(&ct->refcnt);
 554                 return 0;
 555         }
 556         return 1;
 557 }
 558
 559 static void ip_vs_conn_expire(unsigned long data)
 560 {
 561         struct ip_vs_conn *cp = (struct ip_vs_conn *)data;
 562
 563         cp->timeout = 60*HZ;
 564
 565         /*
 566          *      hey, I'm using it
 567          */
 568         atomic_inc(&cp->refcnt);
 569
 570         /*
 571          *      do I control anybody?
 572          */
 573         if (atomic_read(&cp->n_control))
 574                 goto expire_later;
 575
 576         /*
 577          *      unhash it if it is hashed in the conn table
 578          */
 579         if (!ip_vs_conn_unhash(cp))
 580                 goto expire_later;
 581
 582         /*
 583          *      refcnt==1 implies I'm the only one referrer
 584          */
 585         if (likely(atomic_read(&cp->refcnt) == 1)) {
 586                 /* delete the timer if it is activated by other users */
 587                 if (timer_pending(&cp->timer))
 588                         del_timer(&cp->timer);
 589
 590                 /* does anybody control me? */
 591                 if (cp->control)
 592                         ip_vs_control_del(cp);
 593
 594                 if (unlikely(cp->app != NULL))
 595                         ip_vs_unbind_app(cp);
 596                 ip_vs_unbind_dest(cp);
 597                 if (cp->flags & IP_VS_CONN_F_NO_CPORT)
 598                         atomic_dec(&ip_vs_conn_no_cport_cnt);
 599                 atomic_dec(&ip_vs_conn_count);
 600
 601                 kmem_cache_free(ip_vs_conn_cachep, cp);
 602                 return;
 603         }
 604
 605         /* hash it back to the table */
 606         ip_vs_conn_hash(cp);
 607
 608   expire_later:
 609         IP_VS_DBG(7, "delayed: conn->refcnt-1=%d conn->n_control=%d\n",
 610                   atomic_read(&cp->refcnt)-1,
 611                   atomic_read(&cp->n_control));
 612
 613         ip_vs_conn_put(cp);
 614 }
 615
 616
 617 void ip_vs_conn_expire_now(struct ip_vs_conn *cp)
 618 {
 619         if (del_timer(&cp->timer))
 620                 mod_timer(&cp->timer, jiffies);
 621 }
 622
 623
 624 /*
 625  *      Create a new connection entry and hash it into the ip_vs_conn_tab
 626  */
 627 struct ip_vs_conn *
 628 ip_vs_conn_new(int proto, __be32 caddr, __be16 cport, __be32 vaddr, __be16 vport,
 629                __be32 daddr, __be16 dport, unsigned flags,
 630                struct ip_vs_dest *dest)
 631 {
 632         struct ip_vs_conn *cp;
 633         struct ip_vs_protocol *pp = ip_vs_proto_get(proto);
 634
 635         cp = kmem_cache_zalloc(ip_vs_conn_cachep, GFP_ATOMIC);
 636         if (cp == NULL) {
 637                 IP_VS_ERR_RL("ip_vs_conn_new: no memory available.\n");
 638                 return NULL;
 639         }
 640
 641         INIT_LIST_HEAD(&cp->c_list);
 642         setup_timer(&cp->timer, ip_vs_conn_expire, (unsigned long)cp);
 643         cp->protocol       = proto;
 644         cp->caddr          = caddr;
 645         cp->cport          = cport;
 646         cp->vaddr          = vaddr;
 647         cp->vport          = vport;
 648         cp->daddr          = daddr;
 649         cp->dport          = dport;
 650         cp->flags          = flags;
 651         spin_lock_init(&cp->lock);
 652
 653         /*
 654          * Set the entry is referenced by the current thread before hashing
 655          * it in the table, so that other thread run ip_vs_random_dropentry
 656          * but cannot drop this entry.
 657          */
 658         atomic_set(&cp->refcnt, 1);
 659
 660         atomic_set(&cp->n_control, 0);
 661         atomic_set(&cp->in_pkts, 0);
 662
 663         atomic_inc(&ip_vs_conn_count);
 664         if (flags & IP_VS_CONN_F_NO_CPORT)
 665                 atomic_inc(&ip_vs_conn_no_cport_cnt);
 666
 667         /* Bind the connection with a destination server */
 668         ip_vs_bind_dest(cp, dest);
 669
 670         /* Set its state and timeout */
 671         cp->state = 0;
 672         cp->timeout = 3*HZ;
 673
 674         /* Bind its packet transmitter */
 675         ip_vs_bind_xmit(cp);
 676
 677         if (unlikely(pp && atomic_read(&pp->appcnt)))
 678                 ip_vs_bind_app(cp, pp);
 679
 680         /* Hash it in the ip_vs_conn_tab finally */
 681         ip_vs_conn_hash(cp);
 682
 683         return cp;
 684 }
 685
 686
 687 /*
 688  *      /proc/net/ip_vs_conn entries
 689  */
 690 #ifdef CONFIG_PROC_FS
 691
 692 static void *ip_vs_conn_array(struct seq_file *seq, loff_t pos)
 693 {
 694         int idx;
 695         struct ip_vs_conn *cp;
 696
 697         for(idx = 0; idx < IP_VS_CONN_TAB_SIZE; idx++) {
 698                 ct_read_lock_bh(idx);
 699                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 700                         if (pos-- == 0) {
 701                                 seq->private = &ip_vs_conn_tab[idx];
 702                                 return cp;
 703                         }
 704                 }
 705                 ct_read_unlock_bh(idx);
 706         }
 707
 708         return NULL;
 709 }
 710
 711 static void *ip_vs_conn_seq_start(struct seq_file *seq, loff_t *pos)
 712 {
 713         seq->private = NULL;
 714         return *pos ? ip_vs_conn_array(seq, *pos - 1) :SEQ_START_TOKEN;
 715 }
 716
 717 static void *ip_vs_conn_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 718 {
 719         struct ip_vs_conn *cp = v;
 720         struct list_head *e, *l = seq->private;
 721         int idx;
 722
 723         ++*pos;
 724         if (v == SEQ_START_TOKEN)
 725                 return ip_vs_conn_array(seq, 0);
 726
 727         /* more on same hash chain? */
 728         if ((e = cp->c_list.next) != l)
 729                 return list_entry(e, struct ip_vs_conn, c_list);
 730
 731         idx = l - ip_vs_conn_tab;
 732         ct_read_unlock_bh(idx);
 733
 734         while (++idx < IP_VS_CONN_TAB_SIZE) {
 735                 ct_read_lock_bh(idx);
 736                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 737                         seq->private = &ip_vs_conn_tab[idx];
 738                         return cp;
 739                 }
 740                 ct_read_unlock_bh(idx);
 741         }
 742         seq->private = NULL;
 743         return NULL;
 744 }
 745
 746 static void ip_vs_conn_seq_stop(struct seq_file *seq, void *v)
 747 {
 748         struct list_head *l = seq->private;
 749
 750         if (l)
 751                 ct_read_unlock_bh(l - ip_vs_conn_tab);
 752 }
 753
 754 static int ip_vs_conn_seq_show(struct seq_file *seq, void *v)
 755 {
 756
 757         if (v == SEQ_START_TOKEN)
 758                 seq_puts(seq,
 759    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Expires\n");
 760         else {
 761                 const struct ip_vs_conn *cp = v;
 762
 763                 seq_printf(seq,
 764                         "%-3s %08X %04X %08X %04X %08X %04X %-11s %7lu\n",
 765                                 ip_vs_proto_name(cp->protocol),
 766                                 ntohl(cp->caddr), ntohs(cp->cport),
 767                                 ntohl(cp->vaddr), ntohs(cp->vport),
 768                                 ntohl(cp->daddr), ntohs(cp->dport),
 769                                 ip_vs_state_name(cp->protocol, cp->state),
 770                                 (cp->timer.expires-jiffies)/HZ);
 771         }
 772         return 0;
 773 }
 774
 775 static const struct seq_operations ip_vs_conn_seq_ops = {
 776         .start = ip_vs_conn_seq_start,
 777         .next  = ip_vs_conn_seq_next,
 778         .stop  = ip_vs_conn_seq_stop,
 779         .show  = ip_vs_conn_seq_show,
 780 };
 781
 782 static int ip_vs_conn_open(struct inode *inode, struct file *file)
 783 {
 784         return seq_open(file, &ip_vs_conn_seq_ops);
 785 }
 786
 787 static const struct file_operations ip_vs_conn_fops = {
 788         .owner   = THIS_MODULE,
 789         .open    = ip_vs_conn_open,
 790         .read    = seq_read,
 791         .llseek  = seq_lseek,
 792         .release = seq_release,
 793 };
 794
 795 static const char *ip_vs_origin_name(unsigned flags)
 796 {
 797         if (flags & IP_VS_CONN_F_SYNC)
 798                 return "SYNC";
 799         else
 800                 return "LOCAL";
 801 }
 802
 803 static int ip_vs_conn_sync_seq_show(struct seq_file *seq, void *v)
 804 {
 805
 806         if (v == SEQ_START_TOKEN)
 807                 seq_puts(seq,
 808    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Origin Expires\n");
 809         else {
 810                 const struct ip_vs_conn *cp = v;
 811
 812                 seq_printf(seq,
 813                         "%-3s %08X %04X %08X %04X %08X %04X %-11s %-6s %7lu\n",
 814                                 ip_vs_proto_name(cp->protocol),
 815                                 ntohl(cp->caddr), ntohs(cp->cport),
 816                                 ntohl(cp->vaddr), ntohs(cp->vport),
 817                                 ntohl(cp->daddr), ntohs(cp->dport),
 818                                 ip_vs_state_name(cp->protocol, cp->state),
 819                                 ip_vs_origin_name(cp->flags),
 820                                 (cp->timer.expires-jiffies)/HZ);
 821         }
 822         return 0;
 823 }
 824
 825 static const struct seq_operations ip_vs_conn_sync_seq_ops = {
 826         .start = ip_vs_conn_seq_start,
 827         .next  = ip_vs_conn_seq_next,
 828         .stop  = ip_vs_conn_seq_stop,
 829         .show  = ip_vs_conn_sync_seq_show,
 830 };
 831
 832 static int ip_vs_conn_sync_open(struct inode *inode, struct file *file)
 833 {
 834         return seq_open(file, &ip_vs_conn_sync_seq_ops);
 835 }
 836
 837 static const struct file_operations ip_vs_conn_sync_fops = {
 838         .owner   = THIS_MODULE,
 839         .open    = ip_vs_conn_sync_open,
 840         .read    = seq_read,
 841         .llseek  = seq_lseek,
 842         .release = seq_release,
 843 };
 844
 845 #endif
 846
 847
 848 /*
 849  *      Randomly drop connection entries before running out of memory
 850  */
 851 static inline int todrop_entry(struct ip_vs_conn *cp)
 852 {
 853         /*
 854          * The drop rate array needs tuning for real environments.
 855          * Called from timer bh only => no locking
 856          */
 857         static const char todrop_rate[9] = {0, 1, 2, 3, 4, 5, 6, 7, 8};
 858         static char todrop_counter[9] = {0};
 859         int i;
 860
 861         /* if the conn entry hasn't lasted for 60 seconds, don't drop it.
 862            This will leave enough time for normal connection to get
 863            through. */
 864         if (time_before(cp->timeout + jiffies, cp->timer.expires + 60*HZ))
 865                 return 0;
 866
 867         /* Don't drop the entry if its number of incoming packets is not
 868            located in [0, 8] */
 869         i = atomic_read(&cp->in_pkts);
 870         if (i > 8 || i < 0) return 0;
 871
 872         if (!todrop_rate[i]) return 0;
 873         if (--todrop_counter[i] > 0) return 0;
 874
 875         todrop_counter[i] = todrop_rate[i];
 876         return 1;
 877 }
 878
 879 /* Called from keventd and must protect itself from softirqs */
 880 void ip_vs_random_dropentry(void)
 881 {
 882         int idx;
 883         struct ip_vs_conn *cp;
 884
 885         /*
 886          * Randomly scan 1/32 of the whole table every second
 887          */
 888         for (idx = 0; idx < (IP_VS_CONN_TAB_SIZE>>5); idx++) {
 889                 unsigned hash = net_random() & IP_VS_CONN_TAB_MASK;
 890
 891                 /*
 892                  *  Lock is actually needed in this loop.
 893                  */
 894                 ct_write_lock_bh(hash);
 895
 896                 list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 897                         if (cp->flags & IP_VS_CONN_F_TEMPLATE)
 898                                 /* connection template */
 899                                 continue;
 900
 901                         if (cp->protocol == IPPROTO_TCP) {
 902                                 switch(cp->state) {
 903                                 case IP_VS_TCP_S_SYN_RECV:
 904                                 case IP_VS_TCP_S_SYNACK:
 905                                         break;
 906
 907                                 case IP_VS_TCP_S_ESTABLISHED:
 908                                         if (todrop_entry(cp))
 909                                                 break;
 910                                         continue;
 911
 912                                 default:
 913                                         continue;
 914                                 }
 915                         } else {
 916                                 if (!todrop_entry(cp))
 917                                         continue;
 918                         }
 919
 920                         IP_VS_DBG(4, "del connection\n");
 921                         ip_vs_conn_expire_now(cp);
 922                         if (cp->control) {
 923                                 IP_VS_DBG(4, "del conn template\n");
 924                                 ip_vs_conn_expire_now(cp->control);
 925                         }
 926                 }
 927                 ct_write_unlock_bh(hash);
 928         }
 929 }
 930
 931
 932 /*
 933  *      Flush all the connection entries in the ip_vs_conn_tab
 934  */
 935 static void ip_vs_conn_flush(void)
 936 {
 937         int idx;
 938         struct ip_vs_conn *cp;
 939
 940   flush_again:
 941         for (idx=0; idx<IP_VS_CONN_TAB_SIZE; idx++) {
 942                 /*
 943                  *  Lock is actually needed in this loop.
 944                  */
 945                 ct_write_lock_bh(idx);
 946
 947                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 948
 949                         IP_VS_DBG(4, "del connection\n");
 950                         ip_vs_conn_expire_now(cp);
 951                         if (cp->control) {
 952                                 IP_VS_DBG(4, "del conn template\n");
 953                                 ip_vs_conn_expire_now(cp->control);
 954                         }
 955                 }
 956                 ct_write_unlock_bh(idx);
 957         }
 958
 959         /* the counter may be not NULL, because maybe some conn entries
 960            are run by slow timer handler or unhashed but still referred */
 961         if (atomic_read(&ip_vs_conn_count) != 0) {
 962                 schedule();
 963                 goto flush_again;
 964         }
 965 }
 966
 967
 968 int ip_vs_conn_init(void)
 969 {
 970         int idx;
 971
 972         /*
 973          * Allocate the connection hash table and initialize its list heads
 974          */
 975         ip_vs_conn_tab = vmalloc(IP_VS_CONN_TAB_SIZE*sizeof(struct list_head));
 976         if (!ip_vs_conn_tab)
 977                 return -ENOMEM;
 978
 979         /* Allocate ip_vs_conn slab cache */
 980         ip_vs_conn_cachep = kmem_cache_create("ip_vs_conn",
 981                                               sizeof(struct ip_vs_conn), 0,
 982                                               SLAB_HWCACHE_ALIGN, NULL);
 983         if (!ip_vs_conn_cachep) {
 984                 vfree(ip_vs_conn_tab);
 985                 return -ENOMEM;
 986         }
 987
 988         IP_VS_INFO("Connection hash table configured "
 989                    "(size=%d, memory=%ldKbytes)\n",
 990                    IP_VS_CONN_TAB_SIZE,
 991                    (long)(IP_VS_CONN_TAB_SIZE*sizeof(struct list_head))/1024);
 992         IP_VS_DBG(0, "Each connection entry needs %Zd bytes at least\n",
 993                   sizeof(struct ip_vs_conn));
 994
 995         for (idx = 0; idx < IP_VS_CONN_TAB_SIZE; idx++) {
 996                 INIT_LIST_HEAD(&ip_vs_conn_tab[idx]);
 997         }
 998
 999         for (idx = 0; idx < CT_LOCKARRAY_SIZE; idx++)  {
1000                 rwlock_init(&__ip_vs_conntbl_lock_array[idx].l);
1001         }
1002
1003         proc_net_fops_create(&init_net, "ip_vs_conn", 0, &ip_vs_conn_fops);
1004         proc_net_fops_create(&init_net, "ip_vs_conn_sync", 0, &ip_vs_conn_sync_fops);
1005
1006         /* calculate the random value for connection hash */
1007         get_random_bytes(&ip_vs_conn_rnd, sizeof(ip_vs_conn_rnd));
1008
1009         return 0;
1010 }
1011
1012
1013 void ip_vs_conn_cleanup(void)
1014 {
1015         /* flush all the connection entries first */
1016         ip_vs_conn_flush();
1017
1018         /* Release the empty cache */
1019         kmem_cache_destroy(ip_vs_conn_cachep);
1020         proc_net_remove(&init_net, "ip_vs_conn");
1021         proc_net_remove(&init_net, "ip_vs_conn_sync");
1022         vfree(ip_vs_conn_tab);
1023 }