git.oblomov.eu Git - linux-2.6/blob - net/ipv4/ipvs/ip_vs_core.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.
  20  *
  21  * Changes:
  22  *      Paul `Rusty' Russell            properly handle non-linear skbs
  23  *      Harald Welte                    don't use nfcache
  24  *
  25  */
  26
  27 #include <linux/module.h>
  28 #include <linux/kernel.h>
  29 #include <linux/ip.h>
  30 #include <linux/tcp.h>
  31 #include <linux/icmp.h>
  32
  33 #include <net/ip.h>
  34 #include <net/tcp.h>
  35 #include <net/udp.h>
  36 #include <net/icmp.h>                   /* for icmp_send */
  37 #include <net/route.h>
  38
  39 #include <linux/netfilter.h>
  40 #include <linux/netfilter_ipv4.h>
  41
  42 #include <net/ip_vs.h>
  43
  44
  45 EXPORT_SYMBOL(register_ip_vs_scheduler);
  46 EXPORT_SYMBOL(unregister_ip_vs_scheduler);
  47 EXPORT_SYMBOL(ip_vs_skb_replace);
  48 EXPORT_SYMBOL(ip_vs_proto_name);
  49 EXPORT_SYMBOL(ip_vs_conn_new);
  50 EXPORT_SYMBOL(ip_vs_conn_in_get);
  51 EXPORT_SYMBOL(ip_vs_conn_out_get);
  52 #ifdef CONFIG_IP_VS_PROTO_TCP
  53 EXPORT_SYMBOL(ip_vs_tcp_conn_listen);
  54 #endif
  55 EXPORT_SYMBOL(ip_vs_conn_put);
  56 #ifdef CONFIG_IP_VS_DEBUG
  57 EXPORT_SYMBOL(ip_vs_get_debug_level);
  58 #endif
  59
  60
  61 /* ID used in ICMP lookups */
  62 #define icmp_id(icmph)          (((icmph)->un).echo.id)
  63
  64 const char *ip_vs_proto_name(unsigned proto)
  65 {
  66         static char buf[20];
  67
  68         switch (proto) {
  69         case IPPROTO_IP:
  70                 return "IP";
  71         case IPPROTO_UDP:
  72                 return "UDP";
  73         case IPPROTO_TCP:
  74                 return "TCP";
  75         case IPPROTO_ICMP:
  76                 return "ICMP";
  77         default:
  78                 sprintf(buf, "IP_%d", proto);
  79                 return buf;
  80         }
  81 }
  82
  83 void ip_vs_init_hash_table(struct list_head *table, int rows)
  84 {
  85         while (--rows >= 0)
  86                 INIT_LIST_HEAD(&table[rows]);
  87 }
  88
  89 static inline void
  90 ip_vs_in_stats(struct ip_vs_conn *cp, struct sk_buff *skb)
  91 {
  92         struct ip_vs_dest *dest = cp->dest;
  93         if (dest && (dest->flags & IP_VS_DEST_F_AVAILABLE)) {
  94                 spin_lock(&dest->stats.lock);
  95                 dest->stats.inpkts++;
  96                 dest->stats.inbytes += skb->len;
  97                 spin_unlock(&dest->stats.lock);
  98
  99                 spin_lock(&dest->svc->stats.lock);
 100                 dest->svc->stats.inpkts++;
 101                 dest->svc->stats.inbytes += skb->len;
 102                 spin_unlock(&dest->svc->stats.lock);
 103
 104                 spin_lock(&ip_vs_stats.lock);
 105                 ip_vs_stats.inpkts++;
 106                 ip_vs_stats.inbytes += skb->len;
 107                 spin_unlock(&ip_vs_stats.lock);
 108         }
 109 }
 110
 111
 112 static inline void
 113 ip_vs_out_stats(struct ip_vs_conn *cp, struct sk_buff *skb)
 114 {
 115         struct ip_vs_dest *dest = cp->dest;
 116         if (dest && (dest->flags & IP_VS_DEST_F_AVAILABLE)) {
 117                 spin_lock(&dest->stats.lock);
 118                 dest->stats.outpkts++;
 119                 dest->stats.outbytes += skb->len;
 120                 spin_unlock(&dest->stats.lock);
 121
 122                 spin_lock(&dest->svc->stats.lock);
 123                 dest->svc->stats.outpkts++;
 124                 dest->svc->stats.outbytes += skb->len;
 125                 spin_unlock(&dest->svc->stats.lock);
 126
 127                 spin_lock(&ip_vs_stats.lock);
 128                 ip_vs_stats.outpkts++;
 129                 ip_vs_stats.outbytes += skb->len;
 130                 spin_unlock(&ip_vs_stats.lock);
 131         }
 132 }
 133
 134
 135 static inline void
 136 ip_vs_conn_stats(struct ip_vs_conn *cp, struct ip_vs_service *svc)
 137 {
 138         spin_lock(&cp->dest->stats.lock);
 139         cp->dest->stats.conns++;
 140         spin_unlock(&cp->dest->stats.lock);
 141
 142         spin_lock(&svc->stats.lock);
 143         svc->stats.conns++;
 144         spin_unlock(&svc->stats.lock);
 145
 146         spin_lock(&ip_vs_stats.lock);
 147         ip_vs_stats.conns++;
 148         spin_unlock(&ip_vs_stats.lock);
 149 }
 150
 151
 152 static inline int
 153 ip_vs_set_state(struct ip_vs_conn *cp, int direction,
 154                 const struct sk_buff *skb,
 155                 struct ip_vs_protocol *pp)
 156 {
 157         if (unlikely(!pp->state_transition))
 158                 return 0;
 159         return pp->state_transition(cp, direction, skb, pp);
 160 }
 161
 162
 163 /*
 164  *  IPVS persistent scheduling function
 165  *  It creates a connection entry according to its template if exists,
 166  *  or selects a server and creates a connection entry plus a template.
 167  *  Locking: we are svc user (svc->refcnt), so we hold all dests too
 168  *  Protocols supported: TCP, UDP
 169  */
 170 static struct ip_vs_conn *
 171 ip_vs_sched_persist(struct ip_vs_service *svc,
 172                     const struct sk_buff *skb,
 173                     __be16 ports[2])
 174 {
 175         struct ip_vs_conn *cp = NULL;
 176         struct iphdr *iph = ip_hdr(skb);
 177         struct ip_vs_dest *dest;
 178         struct ip_vs_conn *ct;
 179         __be16  dport;   /* destination port to forward */
 180         __be32  snet;    /* source network of the client, after masking */
 181
 182         /* Mask saddr with the netmask to adjust template granularity */
 183         snet = iph->saddr & svc->netmask;
 184
 185         IP_VS_DBG(6, "p-schedule: src %u.%u.%u.%u:%u dest %u.%u.%u.%u:%u "
 186                   "mnet %u.%u.%u.%u\n",
 187                   NIPQUAD(iph->saddr), ntohs(ports[0]),
 188                   NIPQUAD(iph->daddr), ntohs(ports[1]),
 189                   NIPQUAD(snet));
 190
 191         /*
 192          * As far as we know, FTP is a very complicated network protocol, and
 193          * it uses control connection and data connections. For active FTP,
 194          * FTP server initialize data connection to the client, its source port
 195          * is often 20. For passive FTP, FTP server tells the clients the port
 196          * that it passively listens to,  and the client issues the data
 197          * connection. In the tunneling or direct routing mode, the load
 198          * balancer is on the client-to-server half of connection, the port
 199          * number is unknown to the load balancer. So, a conn template like
 200          * <caddr, 0, vaddr, 0, daddr, 0> is created for persistent FTP
 201          * service, and a template like <caddr, 0, vaddr, vport, daddr, dport>
 202          * is created for other persistent services.
 203          */
 204         if (ports[1] == svc->port) {
 205                 /* Check if a template already exists */
 206                 if (svc->port != FTPPORT)
 207                         ct = ip_vs_ct_in_get(iph->protocol, snet, 0,
 208                                                iph->daddr, ports[1]);
 209                 else
 210                         ct = ip_vs_ct_in_get(iph->protocol, snet, 0,
 211                                                iph->daddr, 0);
 212
 213                 if (!ct || !ip_vs_check_template(ct)) {
 214                         /*
 215                          * No template found or the dest of the connection
 216                          * template is not available.
 217                          */
 218                         dest = svc->scheduler->schedule(svc, skb);
 219                         if (dest == NULL) {
 220                                 IP_VS_DBG(1, "p-schedule: no dest found.\n");
 221                                 return NULL;
 222                         }
 223
 224                         /*
 225                          * Create a template like <protocol,caddr,0,
 226                          * vaddr,vport,daddr,dport> for non-ftp service,
 227                          * and <protocol,caddr,0,vaddr,0,daddr,0>
 228                          * for ftp service.
 229                          */
 230                         if (svc->port != FTPPORT)
 231                                 ct = ip_vs_conn_new(iph->protocol,
 232                                                     snet, 0,
 233                                                     iph->daddr,
 234                                                     ports[1],
 235                                                     dest->addr, dest->port,
 236                                                     IP_VS_CONN_F_TEMPLATE,
 237                                                     dest);
 238                         else
 239                                 ct = ip_vs_conn_new(iph->protocol,
 240                                                     snet, 0,
 241                                                     iph->daddr, 0,
 242                                                     dest->addr, 0,
 243                                                     IP_VS_CONN_F_TEMPLATE,
 244                                                     dest);
 245                         if (ct == NULL)
 246                                 return NULL;
 247
 248                         ct->timeout = svc->timeout;
 249                 } else {
 250                         /* set destination with the found template */
 251                         dest = ct->dest;
 252                 }
 253                 dport = dest->port;
 254         } else {
 255                 /*
 256                  * Note: persistent fwmark-based services and persistent
 257                  * port zero service are handled here.
 258                  * fwmark template: <IPPROTO_IP,caddr,0,fwmark,0,daddr,0>
 259                  * port zero template: <protocol,caddr,0,vaddr,0,daddr,0>
 260                  */
 261                 if (svc->fwmark)
 262                         ct = ip_vs_ct_in_get(IPPROTO_IP, snet, 0,
 263                                                htonl(svc->fwmark), 0);
 264                 else
 265                         ct = ip_vs_ct_in_get(iph->protocol, snet, 0,
 266                                                iph->daddr, 0);
 267
 268                 if (!ct || !ip_vs_check_template(ct)) {
 269                         /*
 270                          * If it is not persistent port zero, return NULL,
 271                          * otherwise create a connection template.
 272                          */
 273                         if (svc->port)
 274                                 return NULL;
 275
 276                         dest = svc->scheduler->schedule(svc, skb);
 277                         if (dest == NULL) {
 278                                 IP_VS_DBG(1, "p-schedule: no dest found.\n");
 279                                 return NULL;
 280                         }
 281
 282                         /*
 283                          * Create a template according to the service
 284                          */
 285                         if (svc->fwmark)
 286                                 ct = ip_vs_conn_new(IPPROTO_IP,
 287                                                     snet, 0,
 288                                                     htonl(svc->fwmark), 0,
 289                                                     dest->addr, 0,
 290                                                     IP_VS_CONN_F_TEMPLATE,
 291                                                     dest);
 292                         else
 293                                 ct = ip_vs_conn_new(iph->protocol,
 294                                                     snet, 0,
 295                                                     iph->daddr, 0,
 296                                                     dest->addr, 0,
 297                                                     IP_VS_CONN_F_TEMPLATE,
 298                                                     dest);
 299                         if (ct == NULL)
 300                                 return NULL;
 301
 302                         ct->timeout = svc->timeout;
 303                 } else {
 304                         /* set destination with the found template */
 305                         dest = ct->dest;
 306                 }
 307                 dport = ports[1];
 308         }
 309
 310         /*
 311          *    Create a new connection according to the template
 312          */
 313         cp = ip_vs_conn_new(iph->protocol,
 314                             iph->saddr, ports[0],
 315                             iph->daddr, ports[1],
 316                             dest->addr, dport,
 317                             0,
 318                             dest);
 319         if (cp == NULL) {
 320                 ip_vs_conn_put(ct);
 321                 return NULL;
 322         }
 323
 324         /*
 325          *    Add its control
 326          */
 327         ip_vs_control_add(cp, ct);
 328         ip_vs_conn_put(ct);
 329
 330         ip_vs_conn_stats(cp, svc);
 331         return cp;
 332 }
 333
 334
 335 /*
 336  *  IPVS main scheduling function
 337  *  It selects a server according to the virtual service, and
 338  *  creates a connection entry.
 339  *  Protocols supported: TCP, UDP
 340  */
 341 struct ip_vs_conn *
 342 ip_vs_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
 343 {
 344         struct ip_vs_conn *cp = NULL;
 345         struct iphdr *iph = ip_hdr(skb);
 346         struct ip_vs_dest *dest;
 347         __be16 _ports[2], *pptr;
 348
 349         pptr = skb_header_pointer(skb, iph->ihl*4,
 350                                   sizeof(_ports), _ports);
 351         if (pptr == NULL)
 352                 return NULL;
 353
 354         /*
 355          *    Persistent service
 356          */
 357         if (svc->flags & IP_VS_SVC_F_PERSISTENT)
 358                 return ip_vs_sched_persist(svc, skb, pptr);
 359
 360         /*
 361          *    Non-persistent service
 362          */
 363         if (!svc->fwmark && pptr[1] != svc->port) {
 364                 if (!svc->port)
 365                         IP_VS_ERR("Schedule: port zero only supported "
 366                                   "in persistent services, "
 367                                   "check your ipvs configuration\n");
 368                 return NULL;
 369         }
 370
 371         dest = svc->scheduler->schedule(svc, skb);
 372         if (dest == NULL) {
 373                 IP_VS_DBG(1, "Schedule: no dest found.\n");
 374                 return NULL;
 375         }
 376
 377         /*
 378          *    Create a connection entry.
 379          */
 380         cp = ip_vs_conn_new(iph->protocol,
 381                             iph->saddr, pptr[0],
 382                             iph->daddr, pptr[1],
 383                             dest->addr, dest->port?dest->port:pptr[1],
 384                             0,
 385                             dest);
 386         if (cp == NULL)
 387                 return NULL;
 388
 389         IP_VS_DBG(6, "Schedule fwd:%c c:%u.%u.%u.%u:%u v:%u.%u.%u.%u:%u "
 390                   "d:%u.%u.%u.%u:%u conn->flags:%X conn->refcnt:%d\n",
 391                   ip_vs_fwd_tag(cp),
 392                   NIPQUAD(cp->caddr), ntohs(cp->cport),
 393                   NIPQUAD(cp->vaddr), ntohs(cp->vport),
 394                   NIPQUAD(cp->daddr), ntohs(cp->dport),
 395                   cp->flags, atomic_read(&cp->refcnt));
 396
 397         ip_vs_conn_stats(cp, svc);
 398         return cp;
 399 }
 400
 401
 402 /*
 403  *  Pass or drop the packet.
 404  *  Called by ip_vs_in, when the virtual service is available but
 405  *  no destination is available for a new connection.
 406  */
 407 int ip_vs_leave(struct ip_vs_service *svc, struct sk_buff *skb,
 408                 struct ip_vs_protocol *pp)
 409 {
 410         __be16 _ports[2], *pptr;
 411         struct iphdr *iph = ip_hdr(skb);
 412
 413         pptr = skb_header_pointer(skb, iph->ihl*4,
 414                                   sizeof(_ports), _ports);
 415         if (pptr == NULL) {
 416                 ip_vs_service_put(svc);
 417                 return NF_DROP;
 418         }
 419
 420         /* if it is fwmark-based service, the cache_bypass sysctl is up
 421            and the destination is RTN_UNICAST (and not local), then create
 422            a cache_bypass connection entry */
 423         if (sysctl_ip_vs_cache_bypass && svc->fwmark
 424             && (inet_addr_type(&init_net, iph->daddr) == RTN_UNICAST)) {
 425                 int ret, cs;
 426                 struct ip_vs_conn *cp;
 427
 428                 ip_vs_service_put(svc);
 429
 430                 /* create a new connection entry */
 431                 IP_VS_DBG(6, "ip_vs_leave: create a cache_bypass entry\n");
 432                 cp = ip_vs_conn_new(iph->protocol,
 433                                     iph->saddr, pptr[0],
 434                                     iph->daddr, pptr[1],
 435                                     0, 0,
 436                                     IP_VS_CONN_F_BYPASS,
 437                                     NULL);
 438                 if (cp == NULL)
 439                         return NF_DROP;
 440
 441                 /* statistics */
 442                 ip_vs_in_stats(cp, skb);
 443
 444                 /* set state */
 445                 cs = ip_vs_set_state(cp, IP_VS_DIR_INPUT, skb, pp);
 446
 447                 /* transmit the first SYN packet */
 448                 ret = cp->packet_xmit(skb, cp, pp);
 449                 /* do not touch skb anymore */
 450
 451                 atomic_inc(&cp->in_pkts);
 452                 ip_vs_conn_put(cp);
 453                 return ret;
 454         }
 455
 456         /*
 457          * When the virtual ftp service is presented, packets destined
 458          * for other services on the VIP may get here (except services
 459          * listed in the ipvs table), pass the packets, because it is
 460          * not ipvs job to decide to drop the packets.
 461          */
 462         if ((svc->port == FTPPORT) && (pptr[1] != FTPPORT)) {
 463                 ip_vs_service_put(svc);
 464                 return NF_ACCEPT;
 465         }
 466
 467         ip_vs_service_put(svc);
 468
 469         /*
 470          * Notify the client that the destination is unreachable, and
 471          * release the socket buffer.
 472          * Since it is in IP layer, the TCP socket is not actually
 473          * created, the TCP RST packet cannot be sent, instead that
 474          * ICMP_PORT_UNREACH is sent here no matter it is TCP/UDP. --WZ
 475          */
 476         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
 477         return NF_DROP;
 478 }
 479
 480
 481 /*
 482  *      It is hooked before NF_IP_PRI_NAT_SRC at the NF_INET_POST_ROUTING
 483  *      chain, and is used for VS/NAT.
 484  *      It detects packets for VS/NAT connections and sends the packets
 485  *      immediately. This can avoid that iptable_nat mangles the packets
 486  *      for VS/NAT.
 487  */
 488 static unsigned int ip_vs_post_routing(unsigned int hooknum,
 489                                        struct sk_buff *skb,
 490                                        const struct net_device *in,
 491                                        const struct net_device *out,
 492                                        int (*okfn)(struct sk_buff *))
 493 {
 494         if (!skb->ipvs_property)
 495                 return NF_ACCEPT;
 496         /* The packet was sent from IPVS, exit this chain */
 497         return NF_STOP;
 498 }
 499
 500 __sum16 ip_vs_checksum_complete(struct sk_buff *skb, int offset)
 501 {
 502         return csum_fold(skb_checksum(skb, offset, skb->len - offset, 0));
 503 }
 504
 505 static inline int ip_vs_gather_frags(struct sk_buff *skb, u_int32_t user)
 506 {
 507         int err = ip_defrag(skb, user);
 508
 509         if (!err)
 510                 ip_send_check(ip_hdr(skb));
 511
 512         return err;
 513 }
 514
 515 /*
 516  * Packet has been made sufficiently writable in caller
 517  * - inout: 1=in->out, 0=out->in
 518  */
 519 void ip_vs_nat_icmp(struct sk_buff *skb, struct ip_vs_protocol *pp,
 520                     struct ip_vs_conn *cp, int inout)
 521 {
 522         struct iphdr *iph        = ip_hdr(skb);
 523         unsigned int icmp_offset = iph->ihl*4;
 524         struct icmphdr *icmph    = (struct icmphdr *)(skb_network_header(skb) +
 525                                                       icmp_offset);
 526         struct iphdr *ciph       = (struct iphdr *)(icmph + 1);
 527
 528         if (inout) {
 529                 iph->saddr = cp->vaddr;
 530                 ip_send_check(iph);
 531                 ciph->daddr = cp->vaddr;
 532                 ip_send_check(ciph);
 533         } else {
 534                 iph->daddr = cp->daddr;
 535                 ip_send_check(iph);
 536                 ciph->saddr = cp->daddr;
 537                 ip_send_check(ciph);
 538         }
 539
 540         /* the TCP/UDP port */
 541         if (IPPROTO_TCP == ciph->protocol || IPPROTO_UDP == ciph->protocol) {
 542                 __be16 *ports = (void *)ciph + ciph->ihl*4;
 543
 544                 if (inout)
 545                         ports[1] = cp->vport;
 546                 else
 547                         ports[0] = cp->dport;
 548         }
 549
 550         /* And finally the ICMP checksum */
 551         icmph->checksum = 0;
 552         icmph->checksum = ip_vs_checksum_complete(skb, icmp_offset);
 553         skb->ip_summed = CHECKSUM_UNNECESSARY;
 554
 555         if (inout)
 556                 IP_VS_DBG_PKT(11, pp, skb, (void *)ciph - (void *)iph,
 557                         "Forwarding altered outgoing ICMP");
 558         else
 559                 IP_VS_DBG_PKT(11, pp, skb, (void *)ciph - (void *)iph,
 560                         "Forwarding altered incoming ICMP");
 561 }
 562
 563 /*
 564  *      Handle ICMP messages in the inside-to-outside direction (outgoing).
 565  *      Find any that might be relevant, check against existing connections,
 566  *      forward to the right destination host if relevant.
 567  *      Currently handles error types - unreachable, quench, ttl exceeded.
 568  *      (Only used in VS/NAT)
 569  */
 570 static int ip_vs_out_icmp(struct sk_buff *skb, int *related)
 571 {
 572         struct iphdr *iph;
 573         struct icmphdr  _icmph, *ic;
 574         struct iphdr    _ciph, *cih;    /* The ip header contained within the ICMP */
 575         struct ip_vs_conn *cp;
 576         struct ip_vs_protocol *pp;
 577         unsigned int offset, ihl, verdict;
 578
 579         *related = 1;
 580
 581         /* reassemble IP fragments */
 582         if (ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET)) {
 583                 if (ip_vs_gather_frags(skb, IP_DEFRAG_VS_OUT))
 584                         return NF_STOLEN;
 585         }
 586
 587         iph = ip_hdr(skb);
 588         offset = ihl = iph->ihl * 4;
 589         ic = skb_header_pointer(skb, offset, sizeof(_icmph), &_icmph);
 590         if (ic == NULL)
 591                 return NF_DROP;
 592
 593         IP_VS_DBG(12, "Outgoing ICMP (%d,%d) %u.%u.%u.%u->%u.%u.%u.%u\n",
 594                   ic->type, ntohs(icmp_id(ic)),
 595                   NIPQUAD(iph->saddr), NIPQUAD(iph->daddr));
 596
 597         /*
 598          * Work through seeing if this is for us.
 599          * These checks are supposed to be in an order that means easy
 600          * things are checked first to speed up processing.... however
 601          * this means that some packets will manage to get a long way
 602          * down this stack and then be rejected, but that's life.
 603          */
 604         if ((ic->type != ICMP_DEST_UNREACH) &&
 605             (ic->type != ICMP_SOURCE_QUENCH) &&
 606             (ic->type != ICMP_TIME_EXCEEDED)) {
 607                 *related = 0;
 608                 return NF_ACCEPT;
 609         }
 610
 611         /* Now find the contained IP header */
 612         offset += sizeof(_icmph);
 613         cih = skb_header_pointer(skb, offset, sizeof(_ciph), &_ciph);
 614         if (cih == NULL)
 615                 return NF_ACCEPT; /* The packet looks wrong, ignore */
 616
 617         pp = ip_vs_proto_get(cih->protocol);
 618         if (!pp)
 619                 return NF_ACCEPT;
 620
 621         /* Is the embedded protocol header present? */
 622         if (unlikely(cih->frag_off & htons(IP_OFFSET) &&
 623                      pp->dont_defrag))
 624                 return NF_ACCEPT;
 625
 626         IP_VS_DBG_PKT(11, pp, skb, offset, "Checking outgoing ICMP for");
 627
 628         offset += cih->ihl * 4;
 629
 630         /* The embedded headers contain source and dest in reverse order */
 631         cp = pp->conn_out_get(skb, pp, cih, offset, 1);
 632         if (!cp)
 633                 return NF_ACCEPT;
 634
 635         verdict = NF_DROP;
 636
 637         if (IP_VS_FWD_METHOD(cp) != 0) {
 638                 IP_VS_ERR("shouldn't reach here, because the box is on the "
 639                           "half connection in the tun/dr module.\n");
 640         }
 641
 642         /* Ensure the checksum is correct */
 643         if (!skb_csum_unnecessary(skb) && ip_vs_checksum_complete(skb, ihl)) {
 644                 /* Failed checksum! */
 645                 IP_VS_DBG(1, "Forward ICMP: failed checksum from %d.%d.%d.%d!\n",
 646                           NIPQUAD(iph->saddr));
 647                 goto out;
 648         }
 649
 650         if (IPPROTO_TCP == cih->protocol || IPPROTO_UDP == cih->protocol)
 651                 offset += 2 * sizeof(__u16);
 652         if (!skb_make_writable(skb, offset))
 653                 goto out;
 654
 655         ip_vs_nat_icmp(skb, pp, cp, 1);
 656
 657         /* do the statistics and put it back */
 658         ip_vs_out_stats(cp, skb);
 659
 660         skb->ipvs_property = 1;
 661         verdict = NF_ACCEPT;
 662
 663   out:
 664         __ip_vs_conn_put(cp);
 665
 666         return verdict;
 667 }
 668
 669 static inline int is_tcp_reset(const struct sk_buff *skb)
 670 {
 671         struct tcphdr _tcph, *th;
 672
 673         th = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph);
 674         if (th == NULL)
 675                 return 0;
 676         return th->rst;
 677 }
 678
 679 /*
 680  *      It is hooked at the NF_INET_FORWARD chain, used only for VS/NAT.
 681  *      Check if outgoing packet belongs to the established ip_vs_conn,
 682  *      rewrite addresses of the packet and send it on its way...
 683  */
 684 static unsigned int
 685 ip_vs_out(unsigned int hooknum, struct sk_buff *skb,
 686           const struct net_device *in, const struct net_device *out,
 687           int (*okfn)(struct sk_buff *))
 688 {
 689         struct iphdr    *iph;
 690         struct ip_vs_protocol *pp;
 691         struct ip_vs_conn *cp;
 692         int ihl;
 693
 694         EnterFunction(11);
 695
 696         if (skb->ipvs_property)
 697                 return NF_ACCEPT;
 698
 699         iph = ip_hdr(skb);
 700         if (unlikely(iph->protocol == IPPROTO_ICMP)) {
 701                 int related, verdict = ip_vs_out_icmp(skb, &related);
 702
 703                 if (related)
 704                         return verdict;
 705                 iph = ip_hdr(skb);
 706         }
 707
 708         pp = ip_vs_proto_get(iph->protocol);
 709         if (unlikely(!pp))
 710                 return NF_ACCEPT;
 711
 712         /* reassemble IP fragments */
 713         if (unlikely(iph->frag_off & htons(IP_MF|IP_OFFSET) &&
 714                      !pp->dont_defrag)) {
 715                 if (ip_vs_gather_frags(skb, IP_DEFRAG_VS_OUT))
 716                         return NF_STOLEN;
 717                 iph = ip_hdr(skb);
 718         }
 719
 720         ihl = iph->ihl << 2;
 721
 722         /*
 723          * Check if the packet belongs to an existing entry
 724          */
 725         cp = pp->conn_out_get(skb, pp, iph, ihl, 0);
 726
 727         if (unlikely(!cp)) {
 728                 if (sysctl_ip_vs_nat_icmp_send &&
 729                     (pp->protocol == IPPROTO_TCP ||
 730                      pp->protocol == IPPROTO_UDP)) {
 731                         __be16 _ports[2], *pptr;
 732
 733                         pptr = skb_header_pointer(skb, ihl,
 734                                                   sizeof(_ports), _ports);
 735                         if (pptr == NULL)
 736                                 return NF_ACCEPT;       /* Not for me */
 737                         if (ip_vs_lookup_real_service(iph->protocol,
 738                                                       iph->saddr, pptr[0])) {
 739                                 /*
 740                                  * Notify the real server: there is no
 741                                  * existing entry if it is not RST
 742                                  * packet or not TCP packet.
 743                                  */
 744                                 if (iph->protocol != IPPROTO_TCP
 745                                     || !is_tcp_reset(skb)) {
 746                                         icmp_send(skb,ICMP_DEST_UNREACH,
 747                                                   ICMP_PORT_UNREACH, 0);
 748                                         return NF_DROP;
 749                                 }
 750                         }
 751                 }
 752                 IP_VS_DBG_PKT(12, pp, skb, 0,
 753                               "packet continues traversal as normal");
 754                 return NF_ACCEPT;
 755         }
 756
 757         IP_VS_DBG_PKT(11, pp, skb, 0, "Outgoing packet");
 758
 759         if (!skb_make_writable(skb, ihl))
 760                 goto drop;
 761
 762         /* mangle the packet */
 763         if (pp->snat_handler && !pp->snat_handler(skb, pp, cp))
 764                 goto drop;
 765         ip_hdr(skb)->saddr = cp->vaddr;
 766         ip_send_check(ip_hdr(skb));
 767
 768         /* For policy routing, packets originating from this
 769          * machine itself may be routed differently to packets
 770          * passing through.  We want this packet to be routed as
 771          * if it came from this machine itself.  So re-compute
 772          * the routing information.
 773          */
 774         if (ip_route_me_harder(skb, RTN_LOCAL) != 0)
 775                 goto drop;
 776
 777         IP_VS_DBG_PKT(10, pp, skb, 0, "After SNAT");
 778
 779         ip_vs_out_stats(cp, skb);
 780         ip_vs_set_state(cp, IP_VS_DIR_OUTPUT, skb, pp);
 781         ip_vs_conn_put(cp);
 782
 783         skb->ipvs_property = 1;
 784
 785         LeaveFunction(11);
 786         return NF_ACCEPT;
 787
 788   drop:
 789         ip_vs_conn_put(cp);
 790         kfree_skb(skb);
 791         return NF_STOLEN;
 792 }
 793
 794
 795 /*
 796  *      Handle ICMP messages in the outside-to-inside direction (incoming).
 797  *      Find any that might be relevant, check against existing connections,
 798  *      forward to the right destination host if relevant.
 799  *      Currently handles error types - unreachable, quench, ttl exceeded.
 800  */
 801 static int
 802 ip_vs_in_icmp(struct sk_buff *skb, int *related, unsigned int hooknum)
 803 {
 804         struct iphdr *iph;
 805         struct icmphdr  _icmph, *ic;
 806         struct iphdr    _ciph, *cih;    /* The ip header contained within the ICMP */
 807         struct ip_vs_conn *cp;
 808         struct ip_vs_protocol *pp;
 809         unsigned int offset, ihl, verdict;
 810
 811         *related = 1;
 812
 813         /* reassemble IP fragments */
 814         if (ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET)) {
 815                 if (ip_vs_gather_frags(skb, hooknum == NF_INET_LOCAL_IN ?
 816                                             IP_DEFRAG_VS_IN : IP_DEFRAG_VS_FWD))
 817                         return NF_STOLEN;
 818         }
 819
 820         iph = ip_hdr(skb);
 821         offset = ihl = iph->ihl * 4;
 822         ic = skb_header_pointer(skb, offset, sizeof(_icmph), &_icmph);
 823         if (ic == NULL)
 824                 return NF_DROP;
 825
 826         IP_VS_DBG(12, "Incoming ICMP (%d,%d) %u.%u.%u.%u->%u.%u.%u.%u\n",
 827                   ic->type, ntohs(icmp_id(ic)),
 828                   NIPQUAD(iph->saddr), NIPQUAD(iph->daddr));
 829
 830         /*
 831          * Work through seeing if this is for us.
 832          * These checks are supposed to be in an order that means easy
 833          * things are checked first to speed up processing.... however
 834          * this means that some packets will manage to get a long way
 835          * down this stack and then be rejected, but that's life.
 836          */
 837         if ((ic->type != ICMP_DEST_UNREACH) &&
 838             (ic->type != ICMP_SOURCE_QUENCH) &&
 839             (ic->type != ICMP_TIME_EXCEEDED)) {
 840                 *related = 0;
 841                 return NF_ACCEPT;
 842         }
 843
 844         /* Now find the contained IP header */
 845         offset += sizeof(_icmph);
 846         cih = skb_header_pointer(skb, offset, sizeof(_ciph), &_ciph);
 847         if (cih == NULL)
 848                 return NF_ACCEPT; /* The packet looks wrong, ignore */
 849
 850         pp = ip_vs_proto_get(cih->protocol);
 851         if (!pp)
 852                 return NF_ACCEPT;
 853
 854         /* Is the embedded protocol header present? */
 855         if (unlikely(cih->frag_off & htons(IP_OFFSET) &&
 856                      pp->dont_defrag))
 857                 return NF_ACCEPT;
 858
 859         IP_VS_DBG_PKT(11, pp, skb, offset, "Checking incoming ICMP for");
 860
 861         offset += cih->ihl * 4;
 862
 863         /* The embedded headers contain source and dest in reverse order */
 864         cp = pp->conn_in_get(skb, pp, cih, offset, 1);
 865         if (!cp)
 866                 return NF_ACCEPT;
 867
 868         verdict = NF_DROP;
 869
 870         /* Ensure the checksum is correct */
 871         if (!skb_csum_unnecessary(skb) && ip_vs_checksum_complete(skb, ihl)) {
 872                 /* Failed checksum! */
 873                 IP_VS_DBG(1, "Incoming ICMP: failed checksum from %d.%d.%d.%d!\n",
 874                           NIPQUAD(iph->saddr));
 875                 goto out;
 876         }
 877
 878         /* do the statistics and put it back */
 879         ip_vs_in_stats(cp, skb);
 880         if (IPPROTO_TCP == cih->protocol || IPPROTO_UDP == cih->protocol)
 881                 offset += 2 * sizeof(__u16);
 882         verdict = ip_vs_icmp_xmit(skb, cp, pp, offset);
 883         /* do not touch skb anymore */
 884
 885   out:
 886         __ip_vs_conn_put(cp);
 887
 888         return verdict;
 889 }
 890
 891 /*
 892  *      Check if it's for virtual services, look it up,
 893  *      and send it on its way...
 894  */
 895 static unsigned int
 896 ip_vs_in(unsigned int hooknum, struct sk_buff *skb,
 897          const struct net_device *in, const struct net_device *out,
 898          int (*okfn)(struct sk_buff *))
 899 {
 900         struct iphdr    *iph;
 901         struct ip_vs_protocol *pp;
 902         struct ip_vs_conn *cp;
 903         int ret, restart;
 904         int ihl;
 905
 906         /*
 907          *      Big tappo: only PACKET_HOST (neither loopback nor mcasts)
 908          *      ... don't know why 1st test DOES NOT include 2nd (?)
 909          */
 910         if (unlikely(skb->pkt_type != PACKET_HOST
 911                      || skb->dev->flags & IFF_LOOPBACK || skb->sk)) {
 912                 IP_VS_DBG(12, "packet type=%d proto=%d daddr=%d.%d.%d.%d ignored\n",
 913                           skb->pkt_type,
 914                           ip_hdr(skb)->protocol,
 915                           NIPQUAD(ip_hdr(skb)->daddr));
 916                 return NF_ACCEPT;
 917         }
 918
 919         iph = ip_hdr(skb);
 920         if (unlikely(iph->protocol == IPPROTO_ICMP)) {
 921                 int related, verdict = ip_vs_in_icmp(skb, &related, hooknum);
 922
 923                 if (related)
 924                         return verdict;
 925                 iph = ip_hdr(skb);
 926         }
 927
 928         /* Protocol supported? */
 929         pp = ip_vs_proto_get(iph->protocol);
 930         if (unlikely(!pp))
 931                 return NF_ACCEPT;
 932
 933         ihl = iph->ihl << 2;
 934
 935         /*
 936          * Check if the packet belongs to an existing connection entry
 937          */
 938         cp = pp->conn_in_get(skb, pp, iph, ihl, 0);
 939
 940         if (unlikely(!cp)) {
 941                 int v;
 942
 943                 if (!pp->conn_schedule(skb, pp, &v, &cp))
 944                         return v;
 945         }
 946
 947         if (unlikely(!cp)) {
 948                 /* sorry, all this trouble for a no-hit :) */
 949                 IP_VS_DBG_PKT(12, pp, skb, 0,
 950                               "packet continues traversal as normal");
 951                 return NF_ACCEPT;
 952         }
 953
 954         IP_VS_DBG_PKT(11, pp, skb, 0, "Incoming packet");
 955
 956         /* Check the server status */
 957         if (cp->dest && !(cp->dest->flags & IP_VS_DEST_F_AVAILABLE)) {
 958                 /* the destination server is not available */
 959
 960                 if (sysctl_ip_vs_expire_nodest_conn) {
 961                         /* try to expire the connection immediately */
 962                         ip_vs_conn_expire_now(cp);
 963                 }
 964                 /* don't restart its timer, and silently
 965                    drop the packet. */
 966                 __ip_vs_conn_put(cp);
 967                 return NF_DROP;
 968         }
 969
 970         ip_vs_in_stats(cp, skb);
 971         restart = ip_vs_set_state(cp, IP_VS_DIR_INPUT, skb, pp);
 972         if (cp->packet_xmit)
 973                 ret = cp->packet_xmit(skb, cp, pp);
 974                 /* do not touch skb anymore */
 975         else {
 976                 IP_VS_DBG_RL("warning: packet_xmit is null");
 977                 ret = NF_ACCEPT;
 978         }
 979
 980         /* Increase its packet counter and check if it is needed
 981          * to be synchronized
 982          *
 983          * Sync connection if it is about to close to
 984          * encorage the standby servers to update the connections timeout
 985          */
 986         atomic_inc(&cp->in_pkts);
 987         if ((ip_vs_sync_state & IP_VS_STATE_MASTER) &&
 988             (((cp->protocol != IPPROTO_TCP ||
 989                cp->state == IP_VS_TCP_S_ESTABLISHED) &&
 990               (atomic_read(&cp->in_pkts) % sysctl_ip_vs_sync_threshold[1]
 991                == sysctl_ip_vs_sync_threshold[0])) ||
 992              ((cp->protocol == IPPROTO_TCP) && (cp->old_state != cp->state) &&
 993               ((cp->state == IP_VS_TCP_S_FIN_WAIT) ||
 994                (cp->state == IP_VS_TCP_S_CLOSE)))))
 995                 ip_vs_sync_conn(cp);
 996         cp->old_state = cp->state;
 997
 998         ip_vs_conn_put(cp);
 999         return ret;
1000 }
1001
1002
1003 /*
1004  *      It is hooked at the NF_INET_FORWARD chain, in order to catch ICMP
1005  *      related packets destined for 0.0.0.0/0.
1006  *      When fwmark-based virtual service is used, such as transparent
1007  *      cache cluster, TCP packets can be marked and routed to ip_vs_in,
1008  *      but ICMP destined for 0.0.0.0/0 cannot not be easily marked and
1009  *      sent to ip_vs_in_icmp. So, catch them at the NF_INET_FORWARD chain
1010  *      and send them to ip_vs_in_icmp.
1011  */
1012 static unsigned int
1013 ip_vs_forward_icmp(unsigned int hooknum, struct sk_buff *skb,
1014                    const struct net_device *in, const struct net_device *out,
1015                    int (*okfn)(struct sk_buff *))
1016 {
1017         int r;
1018
1019         if (ip_hdr(skb)->protocol != IPPROTO_ICMP)
1020                 return NF_ACCEPT;
1021
1022         return ip_vs_in_icmp(skb, &r, hooknum);
1023 }
1024
1025
1026 static struct nf_hook_ops ip_vs_ops[] __read_mostly = {
1027         /* After packet filtering, forward packet through VS/DR, VS/TUN,
1028          * or VS/NAT(change destination), so that filtering rules can be
1029          * applied to IPVS. */
1030         {
1031                 .hook           = ip_vs_in,
1032                 .owner          = THIS_MODULE,
1033                 .pf             = PF_INET,
1034                 .hooknum        = NF_INET_LOCAL_IN,
1035                 .priority       = 100,
1036         },
1037         /* After packet filtering, change source only for VS/NAT */
1038         {
1039                 .hook           = ip_vs_out,
1040                 .owner          = THIS_MODULE,
1041                 .pf             = PF_INET,
1042                 .hooknum        = NF_INET_FORWARD,
1043                 .priority       = 100,
1044         },
1045         /* After packet filtering (but before ip_vs_out_icmp), catch icmp
1046          * destined for 0.0.0.0/0, which is for incoming IPVS connections */
1047         {
1048                 .hook           = ip_vs_forward_icmp,
1049                 .owner          = THIS_MODULE,
1050                 .pf             = PF_INET,
1051                 .hooknum        = NF_INET_FORWARD,
1052                 .priority       = 99,
1053         },
1054         /* Before the netfilter connection tracking, exit from POST_ROUTING */
1055         {
1056                 .hook           = ip_vs_post_routing,
1057                 .owner          = THIS_MODULE,
1058                 .pf             = PF_INET,
1059                 .hooknum        = NF_INET_POST_ROUTING,
1060                 .priority       = NF_IP_PRI_NAT_SRC-1,
1061         },
1062 };
1063
1064
1065 /*
1066  *      Initialize IP Virtual Server
1067  */
1068 static int __init ip_vs_init(void)
1069 {
1070         int ret;
1071
1072         ret = ip_vs_control_init();
1073         if (ret < 0) {
1074                 IP_VS_ERR("can't setup control.\n");
1075                 goto cleanup_nothing;
1076         }
1077
1078         ip_vs_protocol_init();
1079
1080         ret = ip_vs_app_init();
1081         if (ret < 0) {
1082                 IP_VS_ERR("can't setup application helper.\n");
1083                 goto cleanup_protocol;
1084         }
1085
1086         ret = ip_vs_conn_init();
1087         if (ret < 0) {
1088                 IP_VS_ERR("can't setup connection table.\n");
1089                 goto cleanup_app;
1090         }
1091
1092         ret = nf_register_hooks(ip_vs_ops, ARRAY_SIZE(ip_vs_ops));
1093         if (ret < 0) {
1094                 IP_VS_ERR("can't register hooks.\n");
1095                 goto cleanup_conn;
1096         }
1097
1098         IP_VS_INFO("ipvs loaded.\n");
1099         return ret;
1100
1101   cleanup_conn:
1102         ip_vs_conn_cleanup();
1103   cleanup_app:
1104         ip_vs_app_cleanup();
1105   cleanup_protocol:
1106         ip_vs_protocol_cleanup();
1107         ip_vs_control_cleanup();
1108   cleanup_nothing:
1109         return ret;
1110 }
1111
1112 static void __exit ip_vs_cleanup(void)
1113 {
1114         nf_unregister_hooks(ip_vs_ops, ARRAY_SIZE(ip_vs_ops));
1115         ip_vs_conn_cleanup();
1116         ip_vs_app_cleanup();
1117         ip_vs_protocol_cleanup();
1118         ip_vs_control_cleanup();
1119         IP_VS_INFO("ipvs unloaded.\n");
1120 }
1121
1122 module_init(ip_vs_init);
1123 module_exit(ip_vs_cleanup);
1124 MODULE_LICENSE("GPL");