net/netfilter/ipvs/ip_vs_conn.c

   1 /*
   2  * IPVS         An implementation of the IP virtual server support for the
   3  *              LINUX operating system.  IPVS is now implemented as a module
   4  *              over the Netfilter framework. IPVS can be used to build a
   5  *              high-performance and highly available server based on a
   6  *              cluster of servers.
   7  *
   8  * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
   9  *              Peter Kese <peter.kese@ijs.si>
  10  *              Julian Anastasov <ja@ssi.bg>
  11  *
  12  *              This program is free software; you can redistribute it and/or
  13  *              modify it under the terms of the GNU General Public License
  14  *              as published by the Free Software Foundation; either version
  15  *              2 of the License, or (at your option) any later version.
  16  *
  17  * The IPVS code for kernel 2.2 was done by Wensong Zhang and Peter Kese,
  18  * with changes/fixes from Julian Anastasov, Lars Marowsky-Bree, Horms
  19  * and others. Many code here is taken from IP MASQ code of kernel 2.2.
  20  *
  21  * Changes:
  22  *
  23  */
  24
  25 #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(int af, unsigned proto,
 118                                        const union nf_inet_addr *addr,
 119                                        __be16 port)
 120 {
 121 #ifdef CONFIG_IP_VS_IPV6
 122         if (af == AF_INET6)
 123                 return jhash_3words(jhash(addr, 16, ip_vs_conn_rnd),
 124                                     (__force u32)port, proto, ip_vs_conn_rnd)
 125                         & IP_VS_CONN_TAB_MASK;
 126 #endif
 127         return jhash_3words((__force u32)addr->ip, (__force u32)port, proto,
 128                             ip_vs_conn_rnd)
 129                 & IP_VS_CONN_TAB_MASK;
 130 }
 131
 132
 133 /*
 134  *      Hashes ip_vs_conn in ip_vs_conn_tab by proto,addr,port.
 135  *      returns bool success.
 136  */
 137 static inline int ip_vs_conn_hash(struct ip_vs_conn *cp)
 138 {
 139         unsigned hash;
 140         int ret;
 141
 142         /* Hash by protocol, client address and port */
 143         hash = ip_vs_conn_hashkey(cp->af, cp->protocol, &cp->caddr, cp->cport);
 144
 145         ct_write_lock(hash);
 146
 147         if (!(cp->flags & IP_VS_CONN_F_HASHED)) {
 148                 list_add(&cp->c_list, &ip_vs_conn_tab[hash]);
 149                 cp->flags |= IP_VS_CONN_F_HASHED;
 150                 atomic_inc(&cp->refcnt);
 151                 ret = 1;
 152         } else {
 153                 IP_VS_ERR("ip_vs_conn_hash(): request for already hashed, "
 154                           "called from %p\n", __builtin_return_address(0));
 155                 ret = 0;
 156         }
 157
 158         ct_write_unlock(hash);
 159
 160         return ret;
 161 }
 162
 163
 164 /*
 165  *      UNhashes ip_vs_conn from ip_vs_conn_tab.
 166  *      returns bool success.
 167  */
 168 static inline int ip_vs_conn_unhash(struct ip_vs_conn *cp)
 169 {
 170         unsigned hash;
 171         int ret;
 172
 173         /* unhash it and decrease its reference counter */
 174         hash = ip_vs_conn_hashkey(cp->af, cp->protocol, &cp->caddr, cp->cport);
 175
 176         ct_write_lock(hash);
 177
 178         if (cp->flags & IP_VS_CONN_F_HASHED) {
 179                 list_del(&cp->c_list);
 180                 cp->flags &= ~IP_VS_CONN_F_HASHED;
 181                 atomic_dec(&cp->refcnt);
 182                 ret = 1;
 183         } else
 184                 ret = 0;
 185
 186         ct_write_unlock(hash);
 187
 188         return ret;
 189 }
 190
 191
 192 /*
 193  *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
 194  *  Called for pkts coming from OUTside-to-INside.
 195  *      s_addr, s_port: pkt source address (foreign host)
 196  *      d_addr, d_port: pkt dest address (load balancer)
 197  */
 198 static inline struct ip_vs_conn *__ip_vs_conn_in_get
 199 (int af, int protocol, const union nf_inet_addr *s_addr, __be16 s_port,
 200  const union nf_inet_addr *d_addr, __be16 d_port)
 201 {
 202         unsigned hash;
 203         struct ip_vs_conn *cp;
 204
 205         hash = ip_vs_conn_hashkey(af, protocol, s_addr, s_port);
 206
 207         ct_read_lock(hash);
 208
 209         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 210                 if (cp->af == af &&
 211                     ip_vs_addr_equal(af, s_addr, &cp->caddr) &&
 212                     ip_vs_addr_equal(af, d_addr, &cp->vaddr) &&
 213                     s_port == cp->cport && d_port == cp->vport &&
 214                     ((!s_port) ^ (!(cp->flags & IP_VS_CONN_F_NO_CPORT))) &&
 215                     protocol == cp->protocol) {
 216                         /* HIT */
 217                         atomic_inc(&cp->refcnt);
 218                         ct_read_unlock(hash);
 219                         return cp;
 220                 }
 221         }
 222
 223         ct_read_unlock(hash);
 224
 225         return NULL;
 226 }
 227
 228 struct ip_vs_conn *ip_vs_conn_in_get
 229 (int af, int protocol, const union nf_inet_addr *s_addr, __be16 s_port,
 230  const union nf_inet_addr *d_addr, __be16 d_port)
 231 {
 232         struct ip_vs_conn *cp;
 233
 234         cp = __ip_vs_conn_in_get(af, protocol, s_addr, s_port, d_addr, d_port);
 235         if (!cp && atomic_read(&ip_vs_conn_no_cport_cnt))
 236                 cp = __ip_vs_conn_in_get(af, protocol, s_addr, 0, d_addr,
 237                                          d_port);
 238
 239         IP_VS_DBG_BUF(9, "lookup/in %s %s:%d->%s:%d %s\n",
 240                       ip_vs_proto_name(protocol),
 241                       IP_VS_DBG_ADDR(af, s_addr), ntohs(s_port),
 242                       IP_VS_DBG_ADDR(af, d_addr), ntohs(d_port),
 243                       cp ? "hit" : "not hit");
 244
 245         return cp;
 246 }
 247
 248 /* Get reference to connection template */
 249 struct ip_vs_conn *ip_vs_ct_in_get
 250 (int af, int protocol, const union nf_inet_addr *s_addr, __be16 s_port,
 251  const union nf_inet_addr *d_addr, __be16 d_port)
 252 {
 253         unsigned hash;
 254         struct ip_vs_conn *cp;
 255
 256         hash = ip_vs_conn_hashkey(af, protocol, s_addr, s_port);
 257
 258         ct_read_lock(hash);
 259
 260         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 261                 if (cp->af == af &&
 262                     ip_vs_addr_equal(af, s_addr, &cp->caddr) &&
 263                     /* protocol should only be IPPROTO_IP if
 264                      * d_addr is a fwmark */
 265                     ip_vs_addr_equal(protocol == IPPROTO_IP ? AF_UNSPEC : af,
 266                                      d_addr, &cp->vaddr) &&
 267                     s_port == cp->cport && d_port == cp->vport &&
 268                     cp->flags & IP_VS_CONN_F_TEMPLATE &&
 269                     protocol == cp->protocol) {
 270                         /* HIT */
 271                         atomic_inc(&cp->refcnt);
 272                         goto out;
 273                 }
 274         }
 275         cp = NULL;
 276
 277   out:
 278         ct_read_unlock(hash);
 279
 280         IP_VS_DBG_BUF(9, "template lookup/in %s %s:%d->%s:%d %s\n",
 281                       ip_vs_proto_name(protocol),
 282                       IP_VS_DBG_ADDR(af, s_addr), ntohs(s_port),
 283                       IP_VS_DBG_ADDR(af, d_addr), ntohs(d_port),
 284                       cp ? "hit" : "not hit");
 285
 286         return cp;
 287 }
 288
 289 /*
 290  *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
 291  *  Called for pkts coming from inside-to-OUTside.
 292  *      s_addr, s_port: pkt source address (inside host)
 293  *      d_addr, d_port: pkt dest address (foreign host)
 294  */
 295 struct ip_vs_conn *ip_vs_conn_out_get
 296 (int af, int protocol, const union nf_inet_addr *s_addr, __be16 s_port,
 297  const union nf_inet_addr *d_addr, __be16 d_port)
 298 {
 299         unsigned hash;
 300         struct ip_vs_conn *cp, *ret=NULL;
 301
 302         /*
 303          *      Check for "full" addressed entries
 304          */
 305         hash = ip_vs_conn_hashkey(af, protocol, d_addr, d_port);
 306
 307         ct_read_lock(hash);
 308
 309         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 310                 if (cp->af == af &&
 311                     ip_vs_addr_equal(af, d_addr, &cp->caddr) &&
 312                     ip_vs_addr_equal(af, s_addr, &cp->daddr) &&
 313                     d_port == cp->cport && s_port == cp->dport &&
 314                     protocol == cp->protocol) {
 315                         /* HIT */
 316                         atomic_inc(&cp->refcnt);
 317                         ret = cp;
 318                         break;
 319                 }
 320         }
 321
 322         ct_read_unlock(hash);
 323
 324         IP_VS_DBG_BUF(9, "lookup/out %s %s:%d->%s:%d %s\n",
 325                       ip_vs_proto_name(protocol),
 326                       IP_VS_DBG_ADDR(af, s_addr), ntohs(s_port),
 327                       IP_VS_DBG_ADDR(af, d_addr), ntohs(d_port),
 328                       ret ? "hit" : "not hit");
 329
 330         return ret;
 331 }
 332
 333
 334 /*
 335  *      Put back the conn and restart its timer with its timeout
 336  */
 337 void ip_vs_conn_put(struct ip_vs_conn *cp)
 338 {
 339         /* reset it expire in its timeout */
 340         mod_timer(&cp->timer, jiffies+cp->timeout);
 341
 342         __ip_vs_conn_put(cp);
 343 }
 344
 345
 346 /*
 347  *      Fill a no_client_port connection with a client port number
 348  */
 349 void ip_vs_conn_fill_cport(struct ip_vs_conn *cp, __be16 cport)
 350 {
 351         if (ip_vs_conn_unhash(cp)) {
 352                 spin_lock(&cp->lock);
 353                 if (cp->flags & IP_VS_CONN_F_NO_CPORT) {
 354                         atomic_dec(&ip_vs_conn_no_cport_cnt);
 355                         cp->flags &= ~IP_VS_CONN_F_NO_CPORT;
 356                         cp->cport = cport;
 357                 }
 358                 spin_unlock(&cp->lock);
 359
 360                 /* hash on new dport */
 361                 ip_vs_conn_hash(cp);
 362         }
 363 }
 364
 365
 366 /*
 367  *      Bind a connection entry with the corresponding packet_xmit.
 368  *      Called by ip_vs_conn_new.
 369  */
 370 static inline void ip_vs_bind_xmit(struct ip_vs_conn *cp)
 371 {
 372         switch (IP_VS_FWD_METHOD(cp)) {
 373         case IP_VS_CONN_F_MASQ:
 374                 cp->packet_xmit = ip_vs_nat_xmit;
 375                 break;
 376
 377         case IP_VS_CONN_F_TUNNEL:
 378                 cp->packet_xmit = ip_vs_tunnel_xmit;
 379                 break;
 380
 381         case IP_VS_CONN_F_DROUTE:
 382                 cp->packet_xmit = ip_vs_dr_xmit;
 383                 break;
 384
 385         case IP_VS_CONN_F_LOCALNODE:
 386                 cp->packet_xmit = ip_vs_null_xmit;
 387                 break;
 388
 389         case IP_VS_CONN_F_BYPASS:
 390                 cp->packet_xmit = ip_vs_bypass_xmit;
 391                 break;
 392         }
 393 }
 394
 395 #ifdef CONFIG_IP_VS_IPV6
 396 static inline void ip_vs_bind_xmit_v6(struct ip_vs_conn *cp)
 397 {
 398         switch (IP_VS_FWD_METHOD(cp)) {
 399         case IP_VS_CONN_F_MASQ:
 400                 cp->packet_xmit = ip_vs_nat_xmit_v6;
 401                 break;
 402
 403         case IP_VS_CONN_F_TUNNEL:
 404                 cp->packet_xmit = ip_vs_tunnel_xmit_v6;
 405                 break;
 406
 407         case IP_VS_CONN_F_DROUTE:
 408                 cp->packet_xmit = ip_vs_dr_xmit_v6;
 409                 break;
 410
 411         case IP_VS_CONN_F_LOCALNODE:
 412                 cp->packet_xmit = ip_vs_null_xmit;
 413                 break;
 414
 415         case IP_VS_CONN_F_BYPASS:
 416                 cp->packet_xmit = ip_vs_bypass_xmit_v6;
 417                 break;
 418         }
 419 }
 420 #endif
 421
 422
 423 static inline int ip_vs_dest_totalconns(struct ip_vs_dest *dest)
 424 {
 425         return atomic_read(&dest->activeconns)
 426                 + atomic_read(&dest->inactconns);
 427 }
 428
 429 /*
 430  *      Bind a connection entry with a virtual service destination
 431  *      Called just after a new connection entry is created.
 432  */
 433 static inline void
 434 ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest *dest)
 435 {
 436         /* if dest is NULL, then return directly */
 437         if (!dest)
 438                 return;
 439
 440         /* Increase the refcnt counter of the dest */
 441         atomic_inc(&dest->refcnt);
 442
 443         /* Bind with the destination and its corresponding transmitter */
 444         if ((cp->flags & IP_VS_CONN_F_SYNC) &&
 445             (!(cp->flags & IP_VS_CONN_F_TEMPLATE)))
 446                 /* if the connection is not template and is created
 447                  * by sync, preserve the activity flag.
 448                  */
 449                 cp->flags |= atomic_read(&dest->conn_flags) &
 450                              (~IP_VS_CONN_F_INACTIVE);
 451         else
 452                 cp->flags |= atomic_read(&dest->conn_flags);
 453         cp->dest = dest;
 454
 455         IP_VS_DBG_BUF(7, "Bind-dest %s c:%s:%d v:%s:%d "
 456                       "d:%s:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 457                       "dest->refcnt:%d\n",
 458                       ip_vs_proto_name(cp->protocol),
 459                       IP_VS_DBG_ADDR(cp->af, &cp->caddr), ntohs(cp->cport),
 460                       IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
 461                       IP_VS_DBG_ADDR(cp->af, &cp->daddr), ntohs(cp->dport),
 462                       ip_vs_fwd_tag(cp), cp->state,
 463                       cp->flags, atomic_read(&cp->refcnt),
 464                       atomic_read(&dest->refcnt));
 465
 466         /* Update the connection counters */
 467         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
 468                 /* It is a normal connection, so increase the inactive
 469                    connection counter because it is in TCP SYNRECV
 470                    state (inactive) or other protocol inacive state */
 471                 if ((cp->flags & IP_VS_CONN_F_SYNC) &&
 472                     (!(cp->flags & IP_VS_CONN_F_INACTIVE)))
 473                         atomic_inc(&dest->activeconns);
 474                 else
 475                         atomic_inc(&dest->inactconns);
 476         } else {
 477                 /* It is a persistent connection/template, so increase
 478                    the peristent connection counter */
 479                 atomic_inc(&dest->persistconns);
 480         }
 481
 482         if (dest->u_threshold != 0 &&
 483             ip_vs_dest_totalconns(dest) >= dest->u_threshold)
 484                 dest->flags |= IP_VS_DEST_F_OVERLOAD;
 485 }
 486
 487
 488 /*
 489  * Check if there is a destination for the connection, if so
 490  * bind the connection to the destination.
 491  */
 492 struct ip_vs_dest *ip_vs_try_bind_dest(struct ip_vs_conn *cp)
 493 {
 494         struct ip_vs_dest *dest;
 495
 496         if ((cp) && (!cp->dest)) {
 497                 dest = ip_vs_find_dest(cp->af, &cp->daddr, cp->dport,
 498                                        &cp->vaddr, cp->vport,
 499                                        cp->protocol);
 500                 ip_vs_bind_dest(cp, dest);
 501                 return dest;
 502         } else
 503                 return NULL;
 504 }
 505
 506
 507 /*
 508  *      Unbind a connection entry with its VS destination
 509  *      Called by the ip_vs_conn_expire function.
 510  */
 511 static inline void ip_vs_unbind_dest(struct ip_vs_conn *cp)
 512 {
 513         struct ip_vs_dest *dest = cp->dest;
 514
 515         if (!dest)
 516                 return;
 517
 518         IP_VS_DBG_BUF(7, "Unbind-dest %s c:%s:%d v:%s:%d "
 519                       "d:%s:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 520                       "dest->refcnt:%d\n",
 521                       ip_vs_proto_name(cp->protocol),
 522                       IP_VS_DBG_ADDR(cp->af, &cp->caddr), ntohs(cp->cport),
 523                       IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
 524                       IP_VS_DBG_ADDR(cp->af, &cp->daddr), ntohs(cp->dport),
 525                       ip_vs_fwd_tag(cp), cp->state,
 526                       cp->flags, atomic_read(&cp->refcnt),
 527                       atomic_read(&dest->refcnt));
 528
 529         /* Update the connection counters */
 530         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
 531                 /* It is a normal connection, so decrease the inactconns
 532                    or activeconns counter */
 533                 if (cp->flags & IP_VS_CONN_F_INACTIVE) {
 534                         atomic_dec(&dest->inactconns);
 535                 } else {
 536                         atomic_dec(&dest->activeconns);
 537                 }
 538         } else {
 539                 /* It is a persistent connection/template, so decrease
 540                    the peristent connection counter */
 541                 atomic_dec(&dest->persistconns);
 542         }
 543
 544         if (dest->l_threshold != 0) {
 545                 if (ip_vs_dest_totalconns(dest) < dest->l_threshold)
 546                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 547         } else if (dest->u_threshold != 0) {
 548                 if (ip_vs_dest_totalconns(dest) * 4 < dest->u_threshold * 3)
 549                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 550         } else {
 551                 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
 552                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 553         }
 554
 555         /*
 556          * Simply decrease the refcnt of the dest, because the
 557          * dest will be either in service's destination list
 558          * or in the trash.
 559          */
 560         atomic_dec(&dest->refcnt);
 561 }
 562
 563
 564 /*
 565  *      Checking if the destination of a connection template is available.
 566  *      If available, return 1, otherwise invalidate this connection
 567  *      template and return 0.
 568  */
 569 int ip_vs_check_template(struct ip_vs_conn *ct)
 570 {
 571         struct ip_vs_dest *dest = ct->dest;
 572
 573         /*
 574          * Checking the dest server status.
 575          */
 576         if ((dest == NULL) ||
 577             !(dest->flags & IP_VS_DEST_F_AVAILABLE) ||
 578             (sysctl_ip_vs_expire_quiescent_template &&
 579              (atomic_read(&dest->weight) == 0))) {
 580                 IP_VS_DBG_BUF(9, "check_template: dest not available for "
 581                               "protocol %s s:%s:%d v:%s:%d "
 582                               "-> d:%s:%d\n",
 583                               ip_vs_proto_name(ct->protocol),
 584                               IP_VS_DBG_ADDR(ct->af, &ct->caddr),
 585                               ntohs(ct->cport),
 586                               IP_VS_DBG_ADDR(ct->af, &ct->vaddr),
 587                               ntohs(ct->vport),
 588                               IP_VS_DBG_ADDR(ct->af, &ct->daddr),
 589                               ntohs(ct->dport));
 590
 591                 /*
 592                  * Invalidate the connection template
 593                  */
 594                 if (ct->vport != htons(0xffff)) {
 595                         if (ip_vs_conn_unhash(ct)) {
 596                                 ct->dport = htons(0xffff);
 597                                 ct->vport = htons(0xffff);
 598                                 ct->cport = 0;
 599                                 ip_vs_conn_hash(ct);
 600                         }
 601                 }
 602
 603                 /*
 604                  * Simply decrease the refcnt of the template,
 605                  * don't restart its timer.
 606                  */
 607                 atomic_dec(&ct->refcnt);
 608                 return 0;
 609         }
 610         return 1;
 611 }
 612
 613 static void ip_vs_conn_expire(unsigned long data)
 614 {
 615         struct ip_vs_conn *cp = (struct ip_vs_conn *)data;
 616
 617         cp->timeout = 60*HZ;
 618
 619         /*
 620          *      hey, I'm using it
 621          */
 622         atomic_inc(&cp->refcnt);
 623
 624         /*
 625          *      do I control anybody?
 626          */
 627         if (atomic_read(&cp->n_control))
 628                 goto expire_later;
 629
 630         /*
 631          *      unhash it if it is hashed in the conn table
 632          */
 633         if (!ip_vs_conn_unhash(cp))
 634                 goto expire_later;
 635
 636         /*
 637          *      refcnt==1 implies I'm the only one referrer
 638          */
 639         if (likely(atomic_read(&cp->refcnt) == 1)) {
 640                 /* delete the timer if it is activated by other users */
 641                 if (timer_pending(&cp->timer))
 642                         del_timer(&cp->timer);
 643
 644                 /* does anybody control me? */
 645                 if (cp->control)
 646                         ip_vs_control_del(cp);
 647
 648                 if (unlikely(cp->app != NULL))
 649                         ip_vs_unbind_app(cp);
 650                 ip_vs_unbind_dest(cp);
 651                 if (cp->flags & IP_VS_CONN_F_NO_CPORT)
 652                         atomic_dec(&ip_vs_conn_no_cport_cnt);
 653                 atomic_dec(&ip_vs_conn_count);
 654
 655                 kmem_cache_free(ip_vs_conn_cachep, cp);
 656                 return;
 657         }
 658
 659         /* hash it back to the table */
 660         ip_vs_conn_hash(cp);
 661
 662   expire_later:
 663         IP_VS_DBG(7, "delayed: conn->refcnt-1=%d conn->n_control=%d\n",
 664                   atomic_read(&cp->refcnt)-1,
 665                   atomic_read(&cp->n_control));
 666
 667         ip_vs_conn_put(cp);
 668 }
 669
 670
 671 void ip_vs_conn_expire_now(struct ip_vs_conn *cp)
 672 {
 673         if (del_timer(&cp->timer))
 674                 mod_timer(&cp->timer, jiffies);
 675 }
 676
 677
 678 /*
 679  *      Create a new connection entry and hash it into the ip_vs_conn_tab
 680  */
 681 struct ip_vs_conn *
 682 ip_vs_conn_new(int af, int proto, const union nf_inet_addr *caddr, __be16 cport,
 683                const union nf_inet_addr *vaddr, __be16 vport,
 684                const union nf_inet_addr *daddr, __be16 dport, unsigned flags,
 685                struct ip_vs_dest *dest)
 686 {
 687         struct ip_vs_conn *cp;
 688         struct ip_vs_protocol *pp = ip_vs_proto_get(proto);
 689
 690         cp = kmem_cache_zalloc(ip_vs_conn_cachep, GFP_ATOMIC);
 691         if (cp == NULL) {
 692                 IP_VS_ERR_RL("ip_vs_conn_new: no memory available.\n");
 693                 return NULL;
 694         }
 695
 696         INIT_LIST_HEAD(&cp->c_list);
 697         setup_timer(&cp->timer, ip_vs_conn_expire, (unsigned long)cp);
 698         cp->af             = af;
 699         cp->protocol       = proto;
 700         ip_vs_addr_copy(af, &cp->caddr, caddr);
 701         cp->cport          = cport;
 702         ip_vs_addr_copy(af, &cp->vaddr, vaddr);
 703         cp->vport          = vport;
 704         /* proto should only be IPPROTO_IP if d_addr is a fwmark */
 705         ip_vs_addr_copy(proto == IPPROTO_IP ? AF_UNSPEC : af,
 706                         &cp->daddr, daddr);
 707         cp->dport          = dport;
 708         cp->flags          = flags;
 709         spin_lock_init(&cp->lock);
 710
 711         /*
 712          * Set the entry is referenced by the current thread before hashing
 713          * it in the table, so that other thread run ip_vs_random_dropentry
 714          * but cannot drop this entry.
 715          */
 716         atomic_set(&cp->refcnt, 1);
 717
 718         atomic_set(&cp->n_control, 0);
 719         atomic_set(&cp->in_pkts, 0);
 720
 721         atomic_inc(&ip_vs_conn_count);
 722         if (flags & IP_VS_CONN_F_NO_CPORT)
 723                 atomic_inc(&ip_vs_conn_no_cport_cnt);
 724
 725         /* Bind the connection with a destination server */
 726         ip_vs_bind_dest(cp, dest);
 727
 728         /* Set its state and timeout */
 729         cp->state = 0;
 730         cp->timeout = 3*HZ;
 731
 732         /* Bind its packet transmitter */
 733 #ifdef CONFIG_IP_VS_IPV6
 734         if (af == AF_INET6)
 735                 ip_vs_bind_xmit_v6(cp);
 736         else
 737 #endif
 738                 ip_vs_bind_xmit(cp);
 739
 740         if (unlikely(pp && atomic_read(&pp->appcnt)))
 741                 ip_vs_bind_app(cp, pp);
 742
 743         /* Hash it in the ip_vs_conn_tab finally */
 744         ip_vs_conn_hash(cp);
 745
 746         return cp;
 747 }
 748
 749
 750 /*
 751  *      /proc/net/ip_vs_conn entries
 752  */
 753 #ifdef CONFIG_PROC_FS
 754
 755 static void *ip_vs_conn_array(struct seq_file *seq, loff_t pos)
 756 {
 757         int idx;
 758         struct ip_vs_conn *cp;
 759
 760         for(idx = 0; idx < IP_VS_CONN_TAB_SIZE; idx++) {
 761                 ct_read_lock_bh(idx);
 762                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 763                         if (pos-- == 0) {
 764                                 seq->private = &ip_vs_conn_tab[idx];
 765                                 return cp;
 766                         }
 767                 }
 768                 ct_read_unlock_bh(idx);
 769         }
 770
 771         return NULL;
 772 }
 773
 774 static void *ip_vs_conn_seq_start(struct seq_file *seq, loff_t *pos)
 775 {
 776         seq->private = NULL;
 777         return *pos ? ip_vs_conn_array(seq, *pos - 1) :SEQ_START_TOKEN;
 778 }
 779
 780 static void *ip_vs_conn_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 781 {
 782         struct ip_vs_conn *cp = v;
 783         struct list_head *e, *l = seq->private;
 784         int idx;
 785
 786         ++*pos;
 787         if (v == SEQ_START_TOKEN)
 788                 return ip_vs_conn_array(seq, 0);
 789
 790         /* more on same hash chain? */
 791         if ((e = cp->c_list.next) != l)
 792                 return list_entry(e, struct ip_vs_conn, c_list);
 793
 794         idx = l - ip_vs_conn_tab;
 795         ct_read_unlock_bh(idx);
 796
 797         while (++idx < IP_VS_CONN_TAB_SIZE) {
 798                 ct_read_lock_bh(idx);
 799                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 800                         seq->private = &ip_vs_conn_tab[idx];
 801                         return cp;
 802                 }
 803                 ct_read_unlock_bh(idx);
 804         }
 805         seq->private = NULL;
 806         return NULL;
 807 }
 808
 809 static void ip_vs_conn_seq_stop(struct seq_file *seq, void *v)
 810 {
 811         struct list_head *l = seq->private;
 812
 813         if (l)
 814                 ct_read_unlock_bh(l - ip_vs_conn_tab);
 815 }
 816
 817 static int ip_vs_conn_seq_show(struct seq_file *seq, void *v)
 818 {
 819
 820         if (v == SEQ_START_TOKEN)
 821                 seq_puts(seq,
 822    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Expires\n");
 823         else {
 824                 const struct ip_vs_conn *cp = v;
 825
 826 #ifdef CONFIG_IP_VS_IPV6
 827                 if (cp->af == AF_INET6)
 828                         seq_printf(seq, "%-3s %pI6 %04X %pI6 %04X %pI6 %04X %-11s %7lu\n",
 829                                 ip_vs_proto_name(cp->protocol),
 830                                 &cp->caddr.in6, ntohs(cp->cport),
 831                                 &cp->vaddr.in6, ntohs(cp->vport),
 832                                 &cp->daddr.in6, ntohs(cp->dport),
 833                                 ip_vs_state_name(cp->protocol, cp->state),
 834                                 (cp->timer.expires-jiffies)/HZ);
 835                 else
 836 #endif
 837                         seq_printf(seq,
 838                                 "%-3s %08X %04X %08X %04X"
 839                                 " %08X %04X %-11s %7lu\n",
 840                                 ip_vs_proto_name(cp->protocol),
 841                                 ntohl(cp->caddr.ip), ntohs(cp->cport),
 842                                 ntohl(cp->vaddr.ip), ntohs(cp->vport),
 843                                 ntohl(cp->daddr.ip), ntohs(cp->dport),
 844                                 ip_vs_state_name(cp->protocol, cp->state),
 845                                 (cp->timer.expires-jiffies)/HZ);
 846         }
 847         return 0;
 848 }
 849
 850 static const struct seq_operations ip_vs_conn_seq_ops = {
 851         .start = ip_vs_conn_seq_start,
 852         .next  = ip_vs_conn_seq_next,
 853         .stop  = ip_vs_conn_seq_stop,
 854         .show  = ip_vs_conn_seq_show,
 855 };
 856
 857 static int ip_vs_conn_open(struct inode *inode, struct file *file)
 858 {
 859         return seq_open(file, &ip_vs_conn_seq_ops);
 860 }
 861
 862 static const struct file_operations ip_vs_conn_fops = {
 863         .owner   = THIS_MODULE,
 864         .open    = ip_vs_conn_open,
 865         .read    = seq_read,
 866         .llseek  = seq_lseek,
 867         .release = seq_release,
 868 };
 869
 870 static const char *ip_vs_origin_name(unsigned flags)
 871 {
 872         if (flags & IP_VS_CONN_F_SYNC)
 873                 return "SYNC";
 874         else
 875                 return "LOCAL";
 876 }
 877
 878 static int ip_vs_conn_sync_seq_show(struct seq_file *seq, void *v)
 879 {
 880
 881         if (v == SEQ_START_TOKEN)
 882                 seq_puts(seq,
 883    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Origin Expires\n");
 884         else {
 885                 const struct ip_vs_conn *cp = v;
 886
 887 #ifdef CONFIG_IP_VS_IPV6
 888                 if (cp->af == AF_INET6)
 889                         seq_printf(seq, "%-3s %pI6 %04X %pI6 %04X %pI6 %04X %-11s %-6s %7lu\n",
 890                                 ip_vs_proto_name(cp->protocol),
 891                                 &cp->caddr.in6, ntohs(cp->cport),
 892                                 &cp->vaddr.in6, ntohs(cp->vport),
 893                                 &cp->daddr.in6, ntohs(cp->dport),
 894                                 ip_vs_state_name(cp->protocol, cp->state),
 895                                 ip_vs_origin_name(cp->flags),
 896                                 (cp->timer.expires-jiffies)/HZ);
 897                 else
 898 #endif
 899                         seq_printf(seq,
 900                                 "%-3s %08X %04X %08X %04X "
 901                                 "%08X %04X %-11s %-6s %7lu\n",
 902                                 ip_vs_proto_name(cp->protocol),
 903                                 ntohl(cp->caddr.ip), ntohs(cp->cport),
 904                                 ntohl(cp->vaddr.ip), ntohs(cp->vport),
 905                                 ntohl(cp->daddr.ip), ntohs(cp->dport),
 906                                 ip_vs_state_name(cp->protocol, cp->state),
 907                                 ip_vs_origin_name(cp->flags),
 908                                 (cp->timer.expires-jiffies)/HZ);
 909         }
 910         return 0;
 911 }
 912
 913 static const struct seq_operations ip_vs_conn_sync_seq_ops = {
 914         .start = ip_vs_conn_seq_start,
 915         .next  = ip_vs_conn_seq_next,
 916         .stop  = ip_vs_conn_seq_stop,
 917         .show  = ip_vs_conn_sync_seq_show,
 918 };
 919
 920 static int ip_vs_conn_sync_open(struct inode *inode, struct file *file)
 921 {
 922         return seq_open(file, &ip_vs_conn_sync_seq_ops);
 923 }
 924
 925 static const struct file_operations ip_vs_conn_sync_fops = {
 926         .owner   = THIS_MODULE,
 927         .open    = ip_vs_conn_sync_open,
 928         .read    = seq_read,
 929         .llseek  = seq_lseek,
 930         .release = seq_release,
 931 };
 932
 933 #endif
 934
 935
 936 /*
 937  *      Randomly drop connection entries before running out of memory
 938  */
 939 static inline int todrop_entry(struct ip_vs_conn *cp)
 940 {
 941         /*
 942          * The drop rate array needs tuning for real environments.
 943          * Called from timer bh only => no locking
 944          */
 945         static const char todrop_rate[9] = {0, 1, 2, 3, 4, 5, 6, 7, 8};
 946         static char todrop_counter[9] = {0};
 947         int i;
 948
 949         /* if the conn entry hasn't lasted for 60 seconds, don't drop it.
 950            This will leave enough time for normal connection to get
 951            through. */
 952         if (time_before(cp->timeout + jiffies, cp->timer.expires + 60*HZ))
 953                 return 0;
 954
 955         /* Don't drop the entry if its number of incoming packets is not
 956            located in [0, 8] */
 957         i = atomic_read(&cp->in_pkts);
 958         if (i > 8 || i < 0) return 0;
 959
 960         if (!todrop_rate[i]) return 0;
 961         if (--todrop_counter[i] > 0) return 0;
 962
 963         todrop_counter[i] = todrop_rate[i];
 964         return 1;
 965 }
 966
 967 /* Called from keventd and must protect itself from softirqs */
 968 void ip_vs_random_dropentry(void)
 969 {
 970         int idx;
 971         struct ip_vs_conn *cp;
 972
 973         /*
 974          * Randomly scan 1/32 of the whole table every second
 975          */
 976         for (idx = 0; idx < (IP_VS_CONN_TAB_SIZE>>5); idx++) {
 977                 unsigned hash = net_random() & IP_VS_CONN_TAB_MASK;
 978
 979                 /*
 980                  *  Lock is actually needed in this loop.
 981                  */
 982                 ct_write_lock_bh(hash);
 983
 984                 list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 985                         if (cp->flags & IP_VS_CONN_F_TEMPLATE)
 986                                 /* connection template */
 987                                 continue;
 988
 989                         if (cp->protocol == IPPROTO_TCP) {
 990                                 switch(cp->state) {
 991                                 case IP_VS_TCP_S_SYN_RECV:
 992                                 case IP_VS_TCP_S_SYNACK:
 993                                         break;
 994
 995                                 case IP_VS_TCP_S_ESTABLISHED:
 996                                         if (todrop_entry(cp))
 997                                                 break;
 998                                         continue;
 999
1000                                 default:
1001                                         continue;
1002                                 }
1003                         } else {
1004                                 if (!todrop_entry(cp))
1005                                         continue;
1006                         }
1007
1008                         IP_VS_DBG(4, "del connection\n");
1009                         ip_vs_conn_expire_now(cp);
1010                         if (cp->control) {
1011                                 IP_VS_DBG(4, "del conn template\n");
1012                                 ip_vs_conn_expire_now(cp->control);
1013                         }
1014                 }
1015                 ct_write_unlock_bh(hash);
1016         }
1017 }
1018
1019
1020 /*
1021  *      Flush all the connection entries in the ip_vs_conn_tab
1022  */
1023 static void ip_vs_conn_flush(void)
1024 {
1025         int idx;
1026         struct ip_vs_conn *cp;
1027
1028   flush_again:
1029         for (idx=0; idx<IP_VS_CONN_TAB_SIZE; idx++) {
1030                 /*
1031                  *  Lock is actually needed in this loop.
1032                  */
1033                 ct_write_lock_bh(idx);
1034
1035                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
1036
1037                         IP_VS_DBG(4, "del connection\n");
1038                         ip_vs_conn_expire_now(cp);
1039                         if (cp->control) {
1040                                 IP_VS_DBG(4, "del conn template\n");
1041                                 ip_vs_conn_expire_now(cp->control);
1042                         }
1043                 }
1044                 ct_write_unlock_bh(idx);
1045         }
1046
1047         /* the counter may be not NULL, because maybe some conn entries
1048            are run by slow timer handler or unhashed but still referred */
1049         if (atomic_read(&ip_vs_conn_count) != 0) {
1050                 schedule();
1051                 goto flush_again;
1052         }
1053 }
1054
1055
1056 int __init ip_vs_conn_init(void)
1057 {
1058         int idx;
1059
1060         /*
1061          * Allocate the connection hash table and initialize its list heads
1062          */
1063         ip_vs_conn_tab = vmalloc(IP_VS_CONN_TAB_SIZE*sizeof(struct list_head));
1064         if (!ip_vs_conn_tab)
1065                 return -ENOMEM;
1066
1067         /* Allocate ip_vs_conn slab cache */
1068         ip_vs_conn_cachep = kmem_cache_create("ip_vs_conn",
1069                                               sizeof(struct ip_vs_conn), 0,
1070                                               SLAB_HWCACHE_ALIGN, NULL);
1071         if (!ip_vs_conn_cachep) {
1072                 vfree(ip_vs_conn_tab);
1073                 return -ENOMEM;
1074         }
1075
1076         IP_VS_INFO("Connection hash table configured "
1077                    "(size=%d, memory=%ldKbytes)\n",
1078                    IP_VS_CONN_TAB_SIZE,
1079                    (long)(IP_VS_CONN_TAB_SIZE*sizeof(struct list_head))/1024);
1080         IP_VS_DBG(0, "Each connection entry needs %Zd bytes at least\n",
1081                   sizeof(struct ip_vs_conn));
1082
1083         for (idx = 0; idx < IP_VS_CONN_TAB_SIZE; idx++) {
1084                 INIT_LIST_HEAD(&ip_vs_conn_tab[idx]);
1085         }
1086
1087         for (idx = 0; idx < CT_LOCKARRAY_SIZE; idx++)  {
1088                 rwlock_init(&__ip_vs_conntbl_lock_array[idx].l);
1089         }
1090
1091         proc_net_fops_create(&init_net, "ip_vs_conn", 0, &ip_vs_conn_fops);
1092         proc_net_fops_create(&init_net, "ip_vs_conn_sync", 0, &ip_vs_conn_sync_fops);
1093
1094         /* calculate the random value for connection hash */
1095         get_random_bytes(&ip_vs_conn_rnd, sizeof(ip_vs_conn_rnd));
1096
1097         return 0;
1098 }
1099
1100
1101 void ip_vs_conn_cleanup(void)
1102 {
1103         /* flush all the connection entries first */
1104         ip_vs_conn_flush();
1105
1106         /* Release the empty cache */
1107         kmem_cache_destroy(ip_vs_conn_cachep);
1108         proc_net_remove(&init_net, "ip_vs_conn");
1109         proc_net_remove(&init_net, "ip_vs_conn_sync");
1110         vfree(ip_vs_conn_tab);
1111 }