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 #define KMSG_COMPONENT "IPVS"
  26 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  27
  28 #include <linux/interrupt.h>
  29 #include <linux/in.h>
  30 #include <linux/net.h>
  31 #include <linux/kernel.h>
  32 #include <linux/module.h>
  33 #include <linux/vmalloc.h>
  34 #include <linux/proc_fs.h>              /* for proc_net_* */
  35 #include <linux/slab.h>
  36 #include <linux/seq_file.h>
  37 #include <linux/jhash.h>
  38 #include <linux/random.h>
  39
  40 #include <net/net_namespace.h>
  41 #include <net/ip_vs.h>
  42
  43
  44 #ifndef CONFIG_IP_VS_TAB_BITS
  45 #define CONFIG_IP_VS_TAB_BITS   12
  46 #endif
  47
  48 /*
  49  * Connection hash size. Default is what was selected at compile time.
  50 */
  51 int ip_vs_conn_tab_bits = CONFIG_IP_VS_TAB_BITS;
  52 module_param_named(conn_tab_bits, ip_vs_conn_tab_bits, int, 0444);
  53 MODULE_PARM_DESC(conn_tab_bits, "Set connections' hash size");
  54
  55 /* size and mask values */
  56 int ip_vs_conn_tab_size;
  57 int ip_vs_conn_tab_mask;
  58
  59 /*
  60  *  Connection hash table: for input and output packets lookups of IPVS
  61  */
  62 static struct list_head *ip_vs_conn_tab;
  63
  64 /*  SLAB cache for IPVS connections */
  65 static struct kmem_cache *ip_vs_conn_cachep __read_mostly;
  66
  67 /*  counter for current IPVS connections */
  68 static atomic_t ip_vs_conn_count = ATOMIC_INIT(0);
  69
  70 /*  counter for no client port connections */
  71 static atomic_t ip_vs_conn_no_cport_cnt = ATOMIC_INIT(0);
  72
  73 /* random value for IPVS connection hash */
  74 static unsigned int ip_vs_conn_rnd;
  75
  76 /*
  77  *  Fine locking granularity for big connection hash table
  78  */
  79 #define CT_LOCKARRAY_BITS  4
  80 #define CT_LOCKARRAY_SIZE  (1<<CT_LOCKARRAY_BITS)
  81 #define CT_LOCKARRAY_MASK  (CT_LOCKARRAY_SIZE-1)
  82
  83 struct ip_vs_aligned_lock
  84 {
  85         rwlock_t        l;
  86 } __attribute__((__aligned__(SMP_CACHE_BYTES)));
  87
  88 /* lock array for conn table */
  89 static struct ip_vs_aligned_lock
  90 __ip_vs_conntbl_lock_array[CT_LOCKARRAY_SIZE] __cacheline_aligned;
  91
  92 static inline void ct_read_lock(unsigned key)
  93 {
  94         read_lock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  95 }
  96
  97 static inline void ct_read_unlock(unsigned key)
  98 {
  99         read_unlock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 100 }
 101
 102 static inline void ct_write_lock(unsigned key)
 103 {
 104         write_lock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 105 }
 106
 107 static inline void ct_write_unlock(unsigned key)
 108 {
 109         write_unlock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 110 }
 111
 112 static inline void ct_read_lock_bh(unsigned key)
 113 {
 114         read_lock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 115 }
 116
 117 static inline void ct_read_unlock_bh(unsigned key)
 118 {
 119         read_unlock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 120 }
 121
 122 static inline void ct_write_lock_bh(unsigned key)
 123 {
 124         write_lock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 125 }
 126
 127 static inline void ct_write_unlock_bh(unsigned key)
 128 {
 129         write_unlock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 130 }
 131
 132
 133 /*
 134  *      Returns hash value for IPVS connection entry
 135  */
 136 static unsigned int ip_vs_conn_hashkey(int af, unsigned proto,
 137                                        const union nf_inet_addr *addr,
 138                                        __be16 port)
 139 {
 140 #ifdef CONFIG_IP_VS_IPV6
 141         if (af == AF_INET6)
 142                 return jhash_3words(jhash(addr, 16, ip_vs_conn_rnd),
 143                                     (__force u32)port, proto, ip_vs_conn_rnd)
 144                         & ip_vs_conn_tab_mask;
 145 #endif
 146         return jhash_3words((__force u32)addr->ip, (__force u32)port, proto,
 147                             ip_vs_conn_rnd)
 148                 & ip_vs_conn_tab_mask;
 149 }
 150
 151
 152 /*
 153  *      Hashes ip_vs_conn in ip_vs_conn_tab by proto,addr,port.
 154  *      returns bool success.
 155  */
 156 static inline int ip_vs_conn_hash(struct ip_vs_conn *cp)
 157 {
 158         unsigned hash;
 159         int ret;
 160
 161         if (cp->flags & IP_VS_CONN_F_ONE_PACKET)
 162                 return 0;
 163
 164         /* Hash by protocol, client address and port */
 165         hash = ip_vs_conn_hashkey(cp->af, cp->protocol, &cp->caddr, cp->cport);
 166
 167         ct_write_lock(hash);
 168         spin_lock(&cp->lock);
 169
 170         if (!(cp->flags & IP_VS_CONN_F_HASHED)) {
 171                 list_add(&cp->c_list, &ip_vs_conn_tab[hash]);
 172                 cp->flags |= IP_VS_CONN_F_HASHED;
 173                 atomic_inc(&cp->refcnt);
 174                 ret = 1;
 175         } else {
 176                 pr_err("%s(): request for already hashed, called from %pF\n",
 177                        __func__, __builtin_return_address(0));
 178                 ret = 0;
 179         }
 180
 181         spin_unlock(&cp->lock);
 182         ct_write_unlock(hash);
 183
 184         return ret;
 185 }
 186
 187
 188 /*
 189  *      UNhashes ip_vs_conn from ip_vs_conn_tab.
 190  *      returns bool success.
 191  */
 192 static inline int ip_vs_conn_unhash(struct ip_vs_conn *cp)
 193 {
 194         unsigned hash;
 195         int ret;
 196
 197         /* unhash it and decrease its reference counter */
 198         hash = ip_vs_conn_hashkey(cp->af, cp->protocol, &cp->caddr, cp->cport);
 199
 200         ct_write_lock(hash);
 201         spin_lock(&cp->lock);
 202
 203         if (cp->flags & IP_VS_CONN_F_HASHED) {
 204                 list_del(&cp->c_list);
 205                 cp->flags &= ~IP_VS_CONN_F_HASHED;
 206                 atomic_dec(&cp->refcnt);
 207                 ret = 1;
 208         } else
 209                 ret = 0;
 210
 211         spin_unlock(&cp->lock);
 212         ct_write_unlock(hash);
 213
 214         return ret;
 215 }
 216
 217
 218 /*
 219  *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
 220  *  Called for pkts coming from OUTside-to-INside.
 221  *      s_addr, s_port: pkt source address (foreign host)
 222  *      d_addr, d_port: pkt dest address (load balancer)
 223  */
 224 static inline struct ip_vs_conn *__ip_vs_conn_in_get
 225 (int af, int protocol, const union nf_inet_addr *s_addr, __be16 s_port,
 226  const union nf_inet_addr *d_addr, __be16 d_port)
 227 {
 228         unsigned hash;
 229         struct ip_vs_conn *cp;
 230
 231         hash = ip_vs_conn_hashkey(af, protocol, s_addr, s_port);
 232
 233         ct_read_lock(hash);
 234
 235         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 236                 if (cp->af == af &&
 237                     ip_vs_addr_equal(af, s_addr, &cp->caddr) &&
 238                     ip_vs_addr_equal(af, d_addr, &cp->vaddr) &&
 239                     s_port == cp->cport && d_port == cp->vport &&
 240                     ((!s_port) ^ (!(cp->flags & IP_VS_CONN_F_NO_CPORT))) &&
 241                     protocol == cp->protocol) {
 242                         /* HIT */
 243                         atomic_inc(&cp->refcnt);
 244                         ct_read_unlock(hash);
 245                         return cp;
 246                 }
 247         }
 248
 249         ct_read_unlock(hash);
 250
 251         return NULL;
 252 }
 253
 254 struct ip_vs_conn *ip_vs_conn_in_get
 255 (int af, int protocol, const union nf_inet_addr *s_addr, __be16 s_port,
 256  const union nf_inet_addr *d_addr, __be16 d_port)
 257 {
 258         struct ip_vs_conn *cp;
 259
 260         cp = __ip_vs_conn_in_get(af, protocol, s_addr, s_port, d_addr, d_port);
 261         if (!cp && atomic_read(&ip_vs_conn_no_cport_cnt))
 262                 cp = __ip_vs_conn_in_get(af, protocol, s_addr, 0, d_addr,
 263                                          d_port);
 264
 265         IP_VS_DBG_BUF(9, "lookup/in %s %s:%d->%s:%d %s\n",
 266                       ip_vs_proto_name(protocol),
 267                       IP_VS_DBG_ADDR(af, s_addr), ntohs(s_port),
 268                       IP_VS_DBG_ADDR(af, d_addr), ntohs(d_port),
 269                       cp ? "hit" : "not hit");
 270
 271         return cp;
 272 }
 273
 274 /* Get reference to connection template */
 275 struct ip_vs_conn *ip_vs_ct_in_get
 276 (int af, int protocol, const union nf_inet_addr *s_addr, __be16 s_port,
 277  const union nf_inet_addr *d_addr, __be16 d_port)
 278 {
 279         unsigned hash;
 280         struct ip_vs_conn *cp;
 281
 282         hash = ip_vs_conn_hashkey(af, protocol, s_addr, s_port);
 283
 284         ct_read_lock(hash);
 285
 286         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 287                 if (cp->af == af &&
 288                     ip_vs_addr_equal(af, s_addr, &cp->caddr) &&
 289                     /* protocol should only be IPPROTO_IP if
 290                      * d_addr is a fwmark */
 291                     ip_vs_addr_equal(protocol == IPPROTO_IP ? AF_UNSPEC : af,
 292                                      d_addr, &cp->vaddr) &&
 293                     s_port == cp->cport && d_port == cp->vport &&
 294                     cp->flags & IP_VS_CONN_F_TEMPLATE &&
 295                     protocol == cp->protocol) {
 296                         /* HIT */
 297                         atomic_inc(&cp->refcnt);
 298                         goto out;
 299                 }
 300         }
 301         cp = NULL;
 302
 303   out:
 304         ct_read_unlock(hash);
 305
 306         IP_VS_DBG_BUF(9, "template lookup/in %s %s:%d->%s:%d %s\n",
 307                       ip_vs_proto_name(protocol),
 308                       IP_VS_DBG_ADDR(af, s_addr), ntohs(s_port),
 309                       IP_VS_DBG_ADDR(af, d_addr), ntohs(d_port),
 310                       cp ? "hit" : "not hit");
 311
 312         return cp;
 313 }
 314
 315 /*
 316  *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
 317  *  Called for pkts coming from inside-to-OUTside.
 318  *      s_addr, s_port: pkt source address (inside host)
 319  *      d_addr, d_port: pkt dest address (foreign host)
 320  */
 321 struct ip_vs_conn *ip_vs_conn_out_get
 322 (int af, int protocol, const union nf_inet_addr *s_addr, __be16 s_port,
 323  const union nf_inet_addr *d_addr, __be16 d_port)
 324 {
 325         unsigned hash;
 326         struct ip_vs_conn *cp, *ret=NULL;
 327
 328         /*
 329          *      Check for "full" addressed entries
 330          */
 331         hash = ip_vs_conn_hashkey(af, protocol, d_addr, d_port);
 332
 333         ct_read_lock(hash);
 334
 335         list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
 336                 if (cp->af == af &&
 337                     ip_vs_addr_equal(af, d_addr, &cp->caddr) &&
 338                     ip_vs_addr_equal(af, s_addr, &cp->daddr) &&
 339                     d_port == cp->cport && s_port == cp->dport &&
 340                     protocol == cp->protocol) {
 341                         /* HIT */
 342                         atomic_inc(&cp->refcnt);
 343                         ret = cp;
 344                         break;
 345                 }
 346         }
 347
 348         ct_read_unlock(hash);
 349
 350         IP_VS_DBG_BUF(9, "lookup/out %s %s:%d->%s:%d %s\n",
 351                       ip_vs_proto_name(protocol),
 352                       IP_VS_DBG_ADDR(af, s_addr), ntohs(s_port),
 353                       IP_VS_DBG_ADDR(af, d_addr), ntohs(d_port),
 354                       ret ? "hit" : "not hit");
 355
 356         return ret;
 357 }
 358
 359
 360 /*
 361  *      Put back the conn and restart its timer with its timeout
 362  */
 363 void ip_vs_conn_put(struct ip_vs_conn *cp)
 364 {
 365         unsigned long t = (cp->flags & IP_VS_CONN_F_ONE_PACKET) ?
 366                 0 : cp->timeout;
 367         mod_timer(&cp->timer, jiffies+t);
 368
 369         __ip_vs_conn_put(cp);
 370 }
 371
 372
 373 /*
 374  *      Fill a no_client_port connection with a client port number
 375  */
 376 void ip_vs_conn_fill_cport(struct ip_vs_conn *cp, __be16 cport)
 377 {
 378         if (ip_vs_conn_unhash(cp)) {
 379                 spin_lock(&cp->lock);
 380                 if (cp->flags & IP_VS_CONN_F_NO_CPORT) {
 381                         atomic_dec(&ip_vs_conn_no_cport_cnt);
 382                         cp->flags &= ~IP_VS_CONN_F_NO_CPORT;
 383                         cp->cport = cport;
 384                 }
 385                 spin_unlock(&cp->lock);
 386
 387                 /* hash on new dport */
 388                 ip_vs_conn_hash(cp);
 389         }
 390 }
 391
 392
 393 /*
 394  *      Bind a connection entry with the corresponding packet_xmit.
 395  *      Called by ip_vs_conn_new.
 396  */
 397 static inline void ip_vs_bind_xmit(struct ip_vs_conn *cp)
 398 {
 399         switch (IP_VS_FWD_METHOD(cp)) {
 400         case IP_VS_CONN_F_MASQ:
 401                 cp->packet_xmit = ip_vs_nat_xmit;
 402                 break;
 403
 404         case IP_VS_CONN_F_TUNNEL:
 405                 cp->packet_xmit = ip_vs_tunnel_xmit;
 406                 break;
 407
 408         case IP_VS_CONN_F_DROUTE:
 409                 cp->packet_xmit = ip_vs_dr_xmit;
 410                 break;
 411
 412         case IP_VS_CONN_F_LOCALNODE:
 413                 cp->packet_xmit = ip_vs_null_xmit;
 414                 break;
 415
 416         case IP_VS_CONN_F_BYPASS:
 417                 cp->packet_xmit = ip_vs_bypass_xmit;
 418                 break;
 419         }
 420 }
 421
 422 #ifdef CONFIG_IP_VS_IPV6
 423 static inline void ip_vs_bind_xmit_v6(struct ip_vs_conn *cp)
 424 {
 425         switch (IP_VS_FWD_METHOD(cp)) {
 426         case IP_VS_CONN_F_MASQ:
 427                 cp->packet_xmit = ip_vs_nat_xmit_v6;
 428                 break;
 429
 430         case IP_VS_CONN_F_TUNNEL:
 431                 cp->packet_xmit = ip_vs_tunnel_xmit_v6;
 432                 break;
 433
 434         case IP_VS_CONN_F_DROUTE:
 435                 cp->packet_xmit = ip_vs_dr_xmit_v6;
 436                 break;
 437
 438         case IP_VS_CONN_F_LOCALNODE:
 439                 cp->packet_xmit = ip_vs_null_xmit;
 440                 break;
 441
 442         case IP_VS_CONN_F_BYPASS:
 443                 cp->packet_xmit = ip_vs_bypass_xmit_v6;
 444                 break;
 445         }
 446 }
 447 #endif
 448
 449
 450 static inline int ip_vs_dest_totalconns(struct ip_vs_dest *dest)
 451 {
 452         return atomic_read(&dest->activeconns)
 453                 + atomic_read(&dest->inactconns);
 454 }
 455
 456 /*
 457  *      Bind a connection entry with a virtual service destination
 458  *      Called just after a new connection entry is created.
 459  */
 460 static inline void
 461 ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest *dest)
 462 {
 463         /* if dest is NULL, then return directly */
 464         if (!dest)
 465                 return;
 466
 467         /* Increase the refcnt counter of the dest */
 468         atomic_inc(&dest->refcnt);
 469
 470         /* Bind with the destination and its corresponding transmitter */
 471         if ((cp->flags & IP_VS_CONN_F_SYNC) &&
 472             (!(cp->flags & IP_VS_CONN_F_TEMPLATE)))
 473                 /* if the connection is not template and is created
 474                  * by sync, preserve the activity flag.
 475                  */
 476                 cp->flags |= atomic_read(&dest->conn_flags) &
 477                              (~IP_VS_CONN_F_INACTIVE);
 478         else
 479                 cp->flags |= atomic_read(&dest->conn_flags);
 480         cp->dest = dest;
 481
 482         IP_VS_DBG_BUF(7, "Bind-dest %s c:%s:%d v:%s:%d "
 483                       "d:%s:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 484                       "dest->refcnt:%d\n",
 485                       ip_vs_proto_name(cp->protocol),
 486                       IP_VS_DBG_ADDR(cp->af, &cp->caddr), ntohs(cp->cport),
 487                       IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
 488                       IP_VS_DBG_ADDR(cp->af, &cp->daddr), ntohs(cp->dport),
 489                       ip_vs_fwd_tag(cp), cp->state,
 490                       cp->flags, atomic_read(&cp->refcnt),
 491                       atomic_read(&dest->refcnt));
 492
 493         /* Update the connection counters */
 494         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
 495                 /* It is a normal connection, so increase the inactive
 496                    connection counter because it is in TCP SYNRECV
 497                    state (inactive) or other protocol inacive state */
 498                 if ((cp->flags & IP_VS_CONN_F_SYNC) &&
 499                     (!(cp->flags & IP_VS_CONN_F_INACTIVE)))
 500                         atomic_inc(&dest->activeconns);
 501                 else
 502                         atomic_inc(&dest->inactconns);
 503         } else {
 504                 /* It is a persistent connection/template, so increase
 505                    the peristent connection counter */
 506                 atomic_inc(&dest->persistconns);
 507         }
 508
 509         if (dest->u_threshold != 0 &&
 510             ip_vs_dest_totalconns(dest) >= dest->u_threshold)
 511                 dest->flags |= IP_VS_DEST_F_OVERLOAD;
 512 }
 513
 514
 515 /*
 516  * Check if there is a destination for the connection, if so
 517  * bind the connection to the destination.
 518  */
 519 struct ip_vs_dest *ip_vs_try_bind_dest(struct ip_vs_conn *cp)
 520 {
 521         struct ip_vs_dest *dest;
 522
 523         if ((cp) && (!cp->dest)) {
 524                 dest = ip_vs_find_dest(cp->af, &cp->daddr, cp->dport,
 525                                        &cp->vaddr, cp->vport,
 526                                        cp->protocol);
 527                 ip_vs_bind_dest(cp, dest);
 528                 return dest;
 529         } else
 530                 return NULL;
 531 }
 532
 533
 534 /*
 535  *      Unbind a connection entry with its VS destination
 536  *      Called by the ip_vs_conn_expire function.
 537  */
 538 static inline void ip_vs_unbind_dest(struct ip_vs_conn *cp)
 539 {
 540         struct ip_vs_dest *dest = cp->dest;
 541
 542         if (!dest)
 543                 return;
 544
 545         IP_VS_DBG_BUF(7, "Unbind-dest %s c:%s:%d v:%s:%d "
 546                       "d:%s:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 547                       "dest->refcnt:%d\n",
 548                       ip_vs_proto_name(cp->protocol),
 549                       IP_VS_DBG_ADDR(cp->af, &cp->caddr), ntohs(cp->cport),
 550                       IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
 551                       IP_VS_DBG_ADDR(cp->af, &cp->daddr), ntohs(cp->dport),
 552                       ip_vs_fwd_tag(cp), cp->state,
 553                       cp->flags, atomic_read(&cp->refcnt),
 554                       atomic_read(&dest->refcnt));
 555
 556         /* Update the connection counters */
 557         if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
 558                 /* It is a normal connection, so decrease the inactconns
 559                    or activeconns counter */
 560                 if (cp->flags & IP_VS_CONN_F_INACTIVE) {
 561                         atomic_dec(&dest->inactconns);
 562                 } else {
 563                         atomic_dec(&dest->activeconns);
 564                 }
 565         } else {
 566                 /* It is a persistent connection/template, so decrease
 567                    the peristent connection counter */
 568                 atomic_dec(&dest->persistconns);
 569         }
 570
 571         if (dest->l_threshold != 0) {
 572                 if (ip_vs_dest_totalconns(dest) < dest->l_threshold)
 573                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 574         } else if (dest->u_threshold != 0) {
 575                 if (ip_vs_dest_totalconns(dest) * 4 < dest->u_threshold * 3)
 576                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 577         } else {
 578                 if (dest->flags & IP_VS_DEST_F_OVERLOAD)
 579                         dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 580         }
 581
 582         /*
 583          * Simply decrease the refcnt of the dest, because the
 584          * dest will be either in service's destination list
 585          * or in the trash.
 586          */
 587         atomic_dec(&dest->refcnt);
 588 }
 589
 590
 591 /*
 592  *      Checking if the destination of a connection template is available.
 593  *      If available, return 1, otherwise invalidate this connection
 594  *      template and return 0.
 595  */
 596 int ip_vs_check_template(struct ip_vs_conn *ct)
 597 {
 598         struct ip_vs_dest *dest = ct->dest;
 599
 600         /*
 601          * Checking the dest server status.
 602          */
 603         if ((dest == NULL) ||
 604             !(dest->flags & IP_VS_DEST_F_AVAILABLE) ||
 605             (sysctl_ip_vs_expire_quiescent_template &&
 606              (atomic_read(&dest->weight) == 0))) {
 607                 IP_VS_DBG_BUF(9, "check_template: dest not available for "
 608                               "protocol %s s:%s:%d v:%s:%d "
 609                               "-> d:%s:%d\n",
 610                               ip_vs_proto_name(ct->protocol),
 611                               IP_VS_DBG_ADDR(ct->af, &ct->caddr),
 612                               ntohs(ct->cport),
 613                               IP_VS_DBG_ADDR(ct->af, &ct->vaddr),
 614                               ntohs(ct->vport),
 615                               IP_VS_DBG_ADDR(ct->af, &ct->daddr),
 616                               ntohs(ct->dport));
 617
 618                 /*
 619                  * Invalidate the connection template
 620                  */
 621                 if (ct->vport != htons(0xffff)) {
 622                         if (ip_vs_conn_unhash(ct)) {
 623                                 ct->dport = htons(0xffff);
 624                                 ct->vport = htons(0xffff);
 625                                 ct->cport = 0;
 626                                 ip_vs_conn_hash(ct);
 627                         }
 628                 }
 629
 630                 /*
 631                  * Simply decrease the refcnt of the template,
 632                  * don't restart its timer.
 633                  */
 634                 atomic_dec(&ct->refcnt);
 635                 return 0;
 636         }
 637         return 1;
 638 }
 639
 640 static void ip_vs_conn_expire(unsigned long data)
 641 {
 642         struct ip_vs_conn *cp = (struct ip_vs_conn *)data;
 643
 644         cp->timeout = 60*HZ;
 645
 646         /*
 647          *      hey, I'm using it
 648          */
 649         atomic_inc(&cp->refcnt);
 650
 651         /*
 652          *      do I control anybody?
 653          */
 654         if (atomic_read(&cp->n_control))
 655                 goto expire_later;
 656
 657         /*
 658          *      unhash it if it is hashed in the conn table
 659          */
 660         if (!ip_vs_conn_unhash(cp) && !(cp->flags & IP_VS_CONN_F_ONE_PACKET))
 661                 goto expire_later;
 662
 663         /*
 664          *      refcnt==1 implies I'm the only one referrer
 665          */
 666         if (likely(atomic_read(&cp->refcnt) == 1)) {
 667                 /* delete the timer if it is activated by other users */
 668                 if (timer_pending(&cp->timer))
 669                         del_timer(&cp->timer);
 670
 671                 /* does anybody control me? */
 672                 if (cp->control)
 673                         ip_vs_control_del(cp);
 674
 675                 if (unlikely(cp->app != NULL))
 676                         ip_vs_unbind_app(cp);
 677                 ip_vs_unbind_dest(cp);
 678                 if (cp->flags & IP_VS_CONN_F_NO_CPORT)
 679                         atomic_dec(&ip_vs_conn_no_cport_cnt);
 680                 atomic_dec(&ip_vs_conn_count);
 681
 682                 kmem_cache_free(ip_vs_conn_cachep, cp);
 683                 return;
 684         }
 685
 686         /* hash it back to the table */
 687         ip_vs_conn_hash(cp);
 688
 689   expire_later:
 690         IP_VS_DBG(7, "delayed: conn->refcnt-1=%d conn->n_control=%d\n",
 691                   atomic_read(&cp->refcnt)-1,
 692                   atomic_read(&cp->n_control));
 693
 694         ip_vs_conn_put(cp);
 695 }
 696
 697
 698 void ip_vs_conn_expire_now(struct ip_vs_conn *cp)
 699 {
 700         if (del_timer(&cp->timer))
 701                 mod_timer(&cp->timer, jiffies);
 702 }
 703
 704
 705 /*
 706  *      Create a new connection entry and hash it into the ip_vs_conn_tab
 707  */
 708 struct ip_vs_conn *
 709 ip_vs_conn_new(int af, int proto, const union nf_inet_addr *caddr, __be16 cport,
 710                const union nf_inet_addr *vaddr, __be16 vport,
 711                const union nf_inet_addr *daddr, __be16 dport, unsigned flags,
 712                struct ip_vs_dest *dest)
 713 {
 714         struct ip_vs_conn *cp;
 715         struct ip_vs_protocol *pp = ip_vs_proto_get(proto);
 716
 717         cp = kmem_cache_zalloc(ip_vs_conn_cachep, GFP_ATOMIC);
 718         if (cp == NULL) {
 719                 IP_VS_ERR_RL("%s(): no memory\n", __func__);
 720                 return NULL;
 721         }
 722
 723         INIT_LIST_HEAD(&cp->c_list);
 724         setup_timer(&cp->timer, ip_vs_conn_expire, (unsigned long)cp);
 725         cp->af             = af;
 726         cp->protocol       = proto;
 727         ip_vs_addr_copy(af, &cp->caddr, caddr);
 728         cp->cport          = cport;
 729         ip_vs_addr_copy(af, &cp->vaddr, vaddr);
 730         cp->vport          = vport;
 731         /* proto should only be IPPROTO_IP if d_addr is a fwmark */
 732         ip_vs_addr_copy(proto == IPPROTO_IP ? AF_UNSPEC : af,
 733                         &cp->daddr, daddr);
 734         cp->dport          = dport;
 735         cp->flags          = flags;
 736         spin_lock_init(&cp->lock);
 737
 738         /*
 739          * Set the entry is referenced by the current thread before hashing
 740          * it in the table, so that other thread run ip_vs_random_dropentry
 741          * but cannot drop this entry.
 742          */
 743         atomic_set(&cp->refcnt, 1);
 744
 745         atomic_set(&cp->n_control, 0);
 746         atomic_set(&cp->in_pkts, 0);
 747
 748         atomic_inc(&ip_vs_conn_count);
 749         if (flags & IP_VS_CONN_F_NO_CPORT)
 750                 atomic_inc(&ip_vs_conn_no_cport_cnt);
 751
 752         /* Bind the connection with a destination server */
 753         ip_vs_bind_dest(cp, dest);
 754
 755         /* Set its state and timeout */
 756         cp->state = 0;
 757         cp->timeout = 3*HZ;
 758
 759         /* Bind its packet transmitter */
 760 #ifdef CONFIG_IP_VS_IPV6
 761         if (af == AF_INET6)
 762                 ip_vs_bind_xmit_v6(cp);
 763         else
 764 #endif
 765                 ip_vs_bind_xmit(cp);
 766
 767         if (unlikely(pp && atomic_read(&pp->appcnt)))
 768                 ip_vs_bind_app(cp, pp);
 769
 770         /* Hash it in the ip_vs_conn_tab finally */
 771         ip_vs_conn_hash(cp);
 772
 773         return cp;
 774 }
 775
 776
 777 /*
 778  *      /proc/net/ip_vs_conn entries
 779  */
 780 #ifdef CONFIG_PROC_FS
 781
 782 static void *ip_vs_conn_array(struct seq_file *seq, loff_t pos)
 783 {
 784         int idx;
 785         struct ip_vs_conn *cp;
 786
 787         for (idx = 0; idx < ip_vs_conn_tab_size; idx++) {
 788                 ct_read_lock_bh(idx);
 789                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 790                         if (pos-- == 0) {
 791                                 seq->private = &ip_vs_conn_tab[idx];
 792                                 return cp;
 793                         }
 794                 }
 795                 ct_read_unlock_bh(idx);
 796         }
 797
 798         return NULL;
 799 }
 800
 801 static void *ip_vs_conn_seq_start(struct seq_file *seq, loff_t *pos)
 802 {
 803         seq->private = NULL;
 804         return *pos ? ip_vs_conn_array(seq, *pos - 1) :SEQ_START_TOKEN;
 805 }
 806
 807 static void *ip_vs_conn_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 808 {
 809         struct ip_vs_conn *cp = v;
 810         struct list_head *e, *l = seq->private;
 811         int idx;
 812
 813         ++*pos;
 814         if (v == SEQ_START_TOKEN)
 815                 return ip_vs_conn_array(seq, 0);
 816
 817         /* more on same hash chain? */
 818         if ((e = cp->c_list.next) != l)
 819                 return list_entry(e, struct ip_vs_conn, c_list);
 820
 821         idx = l - ip_vs_conn_tab;
 822         ct_read_unlock_bh(idx);
 823
 824         while (++idx < ip_vs_conn_tab_size) {
 825                 ct_read_lock_bh(idx);
 826                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
 827                         seq->private = &ip_vs_conn_tab[idx];
 828                         return cp;
 829                 }
 830                 ct_read_unlock_bh(idx);
 831         }
 832         seq->private = NULL;
 833         return NULL;
 834 }
 835
 836 static void ip_vs_conn_seq_stop(struct seq_file *seq, void *v)
 837 {
 838         struct list_head *l = seq->private;
 839
 840         if (l)
 841                 ct_read_unlock_bh(l - ip_vs_conn_tab);
 842 }
 843
 844 static int ip_vs_conn_seq_show(struct seq_file *seq, void *v)
 845 {
 846
 847         if (v == SEQ_START_TOKEN)
 848                 seq_puts(seq,
 849    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Expires\n");
 850         else {
 851                 const struct ip_vs_conn *cp = v;
 852
 853 #ifdef CONFIG_IP_VS_IPV6
 854                 if (cp->af == AF_INET6)
 855                         seq_printf(seq, "%-3s %pI6 %04X %pI6 %04X %pI6 %04X %-11s %7lu\n",
 856                                 ip_vs_proto_name(cp->protocol),
 857                                 &cp->caddr.in6, ntohs(cp->cport),
 858                                 &cp->vaddr.in6, ntohs(cp->vport),
 859                                 &cp->daddr.in6, ntohs(cp->dport),
 860                                 ip_vs_state_name(cp->protocol, cp->state),
 861                                 (cp->timer.expires-jiffies)/HZ);
 862                 else
 863 #endif
 864                         seq_printf(seq,
 865                                 "%-3s %08X %04X %08X %04X"
 866                                 " %08X %04X %-11s %7lu\n",
 867                                 ip_vs_proto_name(cp->protocol),
 868                                 ntohl(cp->caddr.ip), ntohs(cp->cport),
 869                                 ntohl(cp->vaddr.ip), ntohs(cp->vport),
 870                                 ntohl(cp->daddr.ip), ntohs(cp->dport),
 871                                 ip_vs_state_name(cp->protocol, cp->state),
 872                                 (cp->timer.expires-jiffies)/HZ);
 873         }
 874         return 0;
 875 }
 876
 877 static const struct seq_operations ip_vs_conn_seq_ops = {
 878         .start = ip_vs_conn_seq_start,
 879         .next  = ip_vs_conn_seq_next,
 880         .stop  = ip_vs_conn_seq_stop,
 881         .show  = ip_vs_conn_seq_show,
 882 };
 883
 884 static int ip_vs_conn_open(struct inode *inode, struct file *file)
 885 {
 886         return seq_open(file, &ip_vs_conn_seq_ops);
 887 }
 888
 889 static const struct file_operations ip_vs_conn_fops = {
 890         .owner   = THIS_MODULE,
 891         .open    = ip_vs_conn_open,
 892         .read    = seq_read,
 893         .llseek  = seq_lseek,
 894         .release = seq_release,
 895 };
 896
 897 static const char *ip_vs_origin_name(unsigned flags)
 898 {
 899         if (flags & IP_VS_CONN_F_SYNC)
 900                 return "SYNC";
 901         else
 902                 return "LOCAL";
 903 }
 904
 905 static int ip_vs_conn_sync_seq_show(struct seq_file *seq, void *v)
 906 {
 907
 908         if (v == SEQ_START_TOKEN)
 909                 seq_puts(seq,
 910    "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Origin Expires\n");
 911         else {
 912                 const struct ip_vs_conn *cp = v;
 913
 914 #ifdef CONFIG_IP_VS_IPV6
 915                 if (cp->af == AF_INET6)
 916                         seq_printf(seq, "%-3s %pI6 %04X %pI6 %04X %pI6 %04X %-11s %-6s %7lu\n",
 917                                 ip_vs_proto_name(cp->protocol),
 918                                 &cp->caddr.in6, ntohs(cp->cport),
 919                                 &cp->vaddr.in6, ntohs(cp->vport),
 920                                 &cp->daddr.in6, ntohs(cp->dport),
 921                                 ip_vs_state_name(cp->protocol, cp->state),
 922                                 ip_vs_origin_name(cp->flags),
 923                                 (cp->timer.expires-jiffies)/HZ);
 924                 else
 925 #endif
 926                         seq_printf(seq,
 927                                 "%-3s %08X %04X %08X %04X "
 928                                 "%08X %04X %-11s %-6s %7lu\n",
 929                                 ip_vs_proto_name(cp->protocol),
 930                                 ntohl(cp->caddr.ip), ntohs(cp->cport),
 931                                 ntohl(cp->vaddr.ip), ntohs(cp->vport),
 932                                 ntohl(cp->daddr.ip), ntohs(cp->dport),
 933                                 ip_vs_state_name(cp->protocol, cp->state),
 934                                 ip_vs_origin_name(cp->flags),
 935                                 (cp->timer.expires-jiffies)/HZ);
 936         }
 937         return 0;
 938 }
 939
 940 static const struct seq_operations ip_vs_conn_sync_seq_ops = {
 941         .start = ip_vs_conn_seq_start,
 942         .next  = ip_vs_conn_seq_next,
 943         .stop  = ip_vs_conn_seq_stop,
 944         .show  = ip_vs_conn_sync_seq_show,
 945 };
 946
 947 static int ip_vs_conn_sync_open(struct inode *inode, struct file *file)
 948 {
 949         return seq_open(file, &ip_vs_conn_sync_seq_ops);
 950 }
 951
 952 static const struct file_operations ip_vs_conn_sync_fops = {
 953         .owner   = THIS_MODULE,
 954         .open    = ip_vs_conn_sync_open,
 955         .read    = seq_read,
 956         .llseek  = seq_lseek,
 957         .release = seq_release,
 958 };
 959
 960 #endif
 961
 962
 963 /*
 964  *      Randomly drop connection entries before running out of memory
 965  */
 966 static inline int todrop_entry(struct ip_vs_conn *cp)
 967 {
 968         /*
 969          * The drop rate array needs tuning for real environments.
 970          * Called from timer bh only => no locking
 971          */
 972         static const char todrop_rate[9] = {0, 1, 2, 3, 4, 5, 6, 7, 8};
 973         static char todrop_counter[9] = {0};
 974         int i;
 975
 976         /* if the conn entry hasn't lasted for 60 seconds, don't drop it.
 977            This will leave enough time for normal connection to get
 978            through. */
 979         if (time_before(cp->timeout + jiffies, cp->timer.expires + 60*HZ))
 980                 return 0;
 981
 982         /* Don't drop the entry if its number of incoming packets is not
 983            located in [0, 8] */
 984         i = atomic_read(&cp->in_pkts);
 985         if (i > 8 || i < 0) return 0;
 986
 987         if (!todrop_rate[i]) return 0;
 988         if (--todrop_counter[i] > 0) return 0;
 989
 990         todrop_counter[i] = todrop_rate[i];
 991         return 1;
 992 }
 993
 994 /* Called from keventd and must protect itself from softirqs */
 995 void ip_vs_random_dropentry(void)
 996 {
 997         int idx;
 998         struct ip_vs_conn *cp;
 999
1000         /*
1001          * Randomly scan 1/32 of the whole table every second
1002          */
1003         for (idx = 0; idx < (ip_vs_conn_tab_size>>5); idx++) {
1004                 unsigned hash = net_random() & ip_vs_conn_tab_mask;
1005
1006                 /*
1007                  *  Lock is actually needed in this loop.
1008                  */
1009                 ct_write_lock_bh(hash);
1010
1011                 list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
1012                         if (cp->flags & IP_VS_CONN_F_TEMPLATE)
1013                                 /* connection template */
1014                                 continue;
1015
1016                         if (cp->protocol == IPPROTO_TCP) {
1017                                 switch(cp->state) {
1018                                 case IP_VS_TCP_S_SYN_RECV:
1019                                 case IP_VS_TCP_S_SYNACK:
1020                                         break;
1021
1022                                 case IP_VS_TCP_S_ESTABLISHED:
1023                                         if (todrop_entry(cp))
1024                                                 break;
1025                                         continue;
1026
1027                                 default:
1028                                         continue;
1029                                 }
1030                         } else {
1031                                 if (!todrop_entry(cp))
1032                                         continue;
1033                         }
1034
1035                         IP_VS_DBG(4, "del connection\n");
1036                         ip_vs_conn_expire_now(cp);
1037                         if (cp->control) {
1038                                 IP_VS_DBG(4, "del conn template\n");
1039                                 ip_vs_conn_expire_now(cp->control);
1040                         }
1041                 }
1042                 ct_write_unlock_bh(hash);
1043         }
1044 }
1045
1046
1047 /*
1048  *      Flush all the connection entries in the ip_vs_conn_tab
1049  */
1050 static void ip_vs_conn_flush(void)
1051 {
1052         int idx;
1053         struct ip_vs_conn *cp;
1054
1055   flush_again:
1056         for (idx = 0; idx < ip_vs_conn_tab_size; idx++) {
1057                 /*
1058                  *  Lock is actually needed in this loop.
1059                  */
1060                 ct_write_lock_bh(idx);
1061
1062                 list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
1063
1064                         IP_VS_DBG(4, "del connection\n");
1065                         ip_vs_conn_expire_now(cp);
1066                         if (cp->control) {
1067                                 IP_VS_DBG(4, "del conn template\n");
1068                                 ip_vs_conn_expire_now(cp->control);
1069                         }
1070                 }
1071                 ct_write_unlock_bh(idx);
1072         }
1073
1074         /* the counter may be not NULL, because maybe some conn entries
1075            are run by slow timer handler or unhashed but still referred */
1076         if (atomic_read(&ip_vs_conn_count) != 0) {
1077                 schedule();
1078                 goto flush_again;
1079         }
1080 }
1081
1082
1083 int __init ip_vs_conn_init(void)
1084 {
1085         int idx;
1086
1087         /* Compute size and mask */
1088         ip_vs_conn_tab_size = 1 << ip_vs_conn_tab_bits;
1089         ip_vs_conn_tab_mask = ip_vs_conn_tab_size - 1;
1090
1091         /*
1092          * Allocate the connection hash table and initialize its list heads
1093          */
1094         ip_vs_conn_tab = vmalloc(ip_vs_conn_tab_size *
1095                                  sizeof(struct list_head));
1096         if (!ip_vs_conn_tab)
1097                 return -ENOMEM;
1098
1099         /* Allocate ip_vs_conn slab cache */
1100         ip_vs_conn_cachep = kmem_cache_create("ip_vs_conn",
1101                                               sizeof(struct ip_vs_conn), 0,
1102                                               SLAB_HWCACHE_ALIGN, NULL);
1103         if (!ip_vs_conn_cachep) {
1104                 vfree(ip_vs_conn_tab);
1105                 return -ENOMEM;
1106         }
1107
1108         pr_info("Connection hash table configured "
1109                 "(size=%d, memory=%ldKbytes)\n",
1110                 ip_vs_conn_tab_size,
1111                 (long)(ip_vs_conn_tab_size*sizeof(struct list_head))/1024);
1112         IP_VS_DBG(0, "Each connection entry needs %Zd bytes at least\n",
1113                   sizeof(struct ip_vs_conn));
1114
1115         for (idx = 0; idx < ip_vs_conn_tab_size; idx++) {
1116                 INIT_LIST_HEAD(&ip_vs_conn_tab[idx]);
1117         }
1118
1119         for (idx = 0; idx < CT_LOCKARRAY_SIZE; idx++)  {
1120                 rwlock_init(&__ip_vs_conntbl_lock_array[idx].l);
1121         }
1122
1123         proc_net_fops_create(&init_net, "ip_vs_conn", 0, &ip_vs_conn_fops);
1124         proc_net_fops_create(&init_net, "ip_vs_conn_sync", 0, &ip_vs_conn_sync_fops);
1125
1126         /* calculate the random value for connection hash */
1127         get_random_bytes(&ip_vs_conn_rnd, sizeof(ip_vs_conn_rnd));
1128
1129         return 0;
1130 }
1131
1132
1133 void ip_vs_conn_cleanup(void)
1134 {
1135         /* flush all the connection entries first */
1136         ip_vs_conn_flush();
1137
1138         /* Release the empty cache */
1139         kmem_cache_destroy(ip_vs_conn_cachep);
1140         proc_net_remove(&init_net, "ip_vs_conn");
1141         proc_net_remove(&init_net, "ip_vs_conn_sync");
1142         vfree(ip_vs_conn_tab);
1143 }