net/netfilter/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 #define KMSG_COMPONENT "IPVS"
  28 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  29
  30 #include <linux/module.h>
  31 #include <linux/kernel.h>
  32 #include <linux/ip.h>
  33 #include <linux/tcp.h>
  34 #include <linux/sctp.h>
  35 #include <linux/icmp.h>
  36 #include <linux/slab.h>
  37
  38 #include <net/ip.h>
  39 #include <net/tcp.h>
  40 #include <net/udp.h>
  41 #include <net/icmp.h>                   /* for icmp_send */
  42 #include <net/route.h>
  43
  44 #include <linux/netfilter.h>
  45 #include <linux/netfilter_ipv4.h>
  46
  47 #ifdef CONFIG_IP_VS_IPV6
  48 #include <net/ipv6.h>
  49 #include <linux/netfilter_ipv6.h>
  50 #endif
  51
  52 #include <net/ip_vs.h>
  53
  54
  55 EXPORT_SYMBOL(register_ip_vs_scheduler);
  56 EXPORT_SYMBOL(unregister_ip_vs_scheduler);
  57 EXPORT_SYMBOL(ip_vs_proto_name);
  58 EXPORT_SYMBOL(ip_vs_conn_new);
  59 EXPORT_SYMBOL(ip_vs_conn_in_get);
  60 EXPORT_SYMBOL(ip_vs_conn_out_get);
  61 #ifdef CONFIG_IP_VS_PROTO_TCP
  62 EXPORT_SYMBOL(ip_vs_tcp_conn_listen);
  63 #endif
  64 EXPORT_SYMBOL(ip_vs_conn_put);
  65 #ifdef CONFIG_IP_VS_DEBUG
  66 EXPORT_SYMBOL(ip_vs_get_debug_level);
  67 #endif
  68
  69
  70 /* ID used in ICMP lookups */
  71 #define icmp_id(icmph)          (((icmph)->un).echo.id)
  72 #define icmpv6_id(icmph)        (icmph->icmp6_dataun.u_echo.identifier)
  73
  74 const char *ip_vs_proto_name(unsigned proto)
  75 {
  76         static char buf[20];
  77
  78         switch (proto) {
  79         case IPPROTO_IP:
  80                 return "IP";
  81         case IPPROTO_UDP:
  82                 return "UDP";
  83         case IPPROTO_TCP:
  84                 return "TCP";
  85         case IPPROTO_SCTP:
  86                 return "SCTP";
  87         case IPPROTO_ICMP:
  88                 return "ICMP";
  89 #ifdef CONFIG_IP_VS_IPV6
  90         case IPPROTO_ICMPV6:
  91                 return "ICMPv6";
  92 #endif
  93         default:
  94                 sprintf(buf, "IP_%d", proto);
  95                 return buf;
  96         }
  97 }
  98
  99 void ip_vs_init_hash_table(struct list_head *table, int rows)
 100 {
 101         while (--rows >= 0)
 102                 INIT_LIST_HEAD(&table[rows]);
 103 }
 104
 105 static inline void
 106 ip_vs_in_stats(struct ip_vs_conn *cp, struct sk_buff *skb)
 107 {
 108         struct ip_vs_dest *dest = cp->dest;
 109         if (dest && (dest->flags & IP_VS_DEST_F_AVAILABLE)) {
 110                 spin_lock(&dest->stats.lock);
 111                 dest->stats.ustats.inpkts++;
 112                 dest->stats.ustats.inbytes += skb->len;
 113                 spin_unlock(&dest->stats.lock);
 114
 115                 spin_lock(&dest->svc->stats.lock);
 116                 dest->svc->stats.ustats.inpkts++;
 117                 dest->svc->stats.ustats.inbytes += skb->len;
 118                 spin_unlock(&dest->svc->stats.lock);
 119
 120                 spin_lock(&ip_vs_stats.lock);
 121                 ip_vs_stats.ustats.inpkts++;
 122                 ip_vs_stats.ustats.inbytes += skb->len;
 123                 spin_unlock(&ip_vs_stats.lock);
 124         }
 125 }
 126
 127
 128 static inline void
 129 ip_vs_out_stats(struct ip_vs_conn *cp, struct sk_buff *skb)
 130 {
 131         struct ip_vs_dest *dest = cp->dest;
 132         if (dest && (dest->flags & IP_VS_DEST_F_AVAILABLE)) {
 133                 spin_lock(&dest->stats.lock);
 134                 dest->stats.ustats.outpkts++;
 135                 dest->stats.ustats.outbytes += skb->len;
 136                 spin_unlock(&dest->stats.lock);
 137
 138                 spin_lock(&dest->svc->stats.lock);
 139                 dest->svc->stats.ustats.outpkts++;
 140                 dest->svc->stats.ustats.outbytes += skb->len;
 141                 spin_unlock(&dest->svc->stats.lock);
 142
 143                 spin_lock(&ip_vs_stats.lock);
 144                 ip_vs_stats.ustats.outpkts++;
 145                 ip_vs_stats.ustats.outbytes += skb->len;
 146                 spin_unlock(&ip_vs_stats.lock);
 147         }
 148 }
 149
 150
 151 static inline void
 152 ip_vs_conn_stats(struct ip_vs_conn *cp, struct ip_vs_service *svc)
 153 {
 154         spin_lock(&cp->dest->stats.lock);
 155         cp->dest->stats.ustats.conns++;
 156         spin_unlock(&cp->dest->stats.lock);
 157
 158         spin_lock(&svc->stats.lock);
 159         svc->stats.ustats.conns++;
 160         spin_unlock(&svc->stats.lock);
 161
 162         spin_lock(&ip_vs_stats.lock);
 163         ip_vs_stats.ustats.conns++;
 164         spin_unlock(&ip_vs_stats.lock);
 165 }
 166
 167
 168 static inline int
 169 ip_vs_set_state(struct ip_vs_conn *cp, int direction,
 170                 const struct sk_buff *skb,
 171                 struct ip_vs_protocol *pp)
 172 {
 173         if (unlikely(!pp->state_transition))
 174                 return 0;
 175         return pp->state_transition(cp, direction, skb, pp);
 176 }
 177
 178
 179 /*
 180  *  IPVS persistent scheduling function
 181  *  It creates a connection entry according to its template if exists,
 182  *  or selects a server and creates a connection entry plus a template.
 183  *  Locking: we are svc user (svc->refcnt), so we hold all dests too
 184  *  Protocols supported: TCP, UDP
 185  */
 186 static struct ip_vs_conn *
 187 ip_vs_sched_persist(struct ip_vs_service *svc,
 188                     const struct sk_buff *skb,
 189                     __be16 ports[2])
 190 {
 191         struct ip_vs_conn *cp = NULL;
 192         struct ip_vs_iphdr iph;
 193         struct ip_vs_dest *dest;
 194         struct ip_vs_conn *ct;
 195         __be16  dport;                  /* destination port to forward */
 196         __be16  flags;
 197         union nf_inet_addr snet;        /* source network of the client,
 198                                            after masking */
 199
 200         ip_vs_fill_iphdr(svc->af, skb_network_header(skb), &iph);
 201
 202         /* Mask saddr with the netmask to adjust template granularity */
 203 #ifdef CONFIG_IP_VS_IPV6
 204         if (svc->af == AF_INET6)
 205                 ipv6_addr_prefix(&snet.in6, &iph.saddr.in6, svc->netmask);
 206         else
 207 #endif
 208                 snet.ip = iph.saddr.ip & svc->netmask;
 209
 210         IP_VS_DBG_BUF(6, "p-schedule: src %s:%u dest %s:%u "
 211                       "mnet %s\n",
 212                       IP_VS_DBG_ADDR(svc->af, &iph.saddr), ntohs(ports[0]),
 213                       IP_VS_DBG_ADDR(svc->af, &iph.daddr), ntohs(ports[1]),
 214                       IP_VS_DBG_ADDR(svc->af, &snet));
 215
 216         /*
 217          * As far as we know, FTP is a very complicated network protocol, and
 218          * it uses control connection and data connections. For active FTP,
 219          * FTP server initialize data connection to the client, its source port
 220          * is often 20. For passive FTP, FTP server tells the clients the port
 221          * that it passively listens to,  and the client issues the data
 222          * connection. In the tunneling or direct routing mode, the load
 223          * balancer is on the client-to-server half of connection, the port
 224          * number is unknown to the load balancer. So, a conn template like
 225          * <caddr, 0, vaddr, 0, daddr, 0> is created for persistent FTP
 226          * service, and a template like <caddr, 0, vaddr, vport, daddr, dport>
 227          * is created for other persistent services.
 228          */
 229         if (ports[1] == svc->port) {
 230                 /* Check if a template already exists */
 231                 if (svc->port != FTPPORT)
 232                         ct = ip_vs_ct_in_get(svc->af, iph.protocol, &snet, 0,
 233                                              &iph.daddr, ports[1]);
 234                 else
 235                         ct = ip_vs_ct_in_get(svc->af, iph.protocol, &snet, 0,
 236                                              &iph.daddr, 0);
 237
 238                 if (!ct || !ip_vs_check_template(ct)) {
 239                         /*
 240                          * No template found or the dest of the connection
 241                          * template is not available.
 242                          */
 243                         dest = svc->scheduler->schedule(svc, skb);
 244                         if (dest == NULL) {
 245                                 IP_VS_DBG(1, "p-schedule: no dest found.\n");
 246                                 return NULL;
 247                         }
 248
 249                         /*
 250                          * Create a template like <protocol,caddr,0,
 251                          * vaddr,vport,daddr,dport> for non-ftp service,
 252                          * and <protocol,caddr,0,vaddr,0,daddr,0>
 253                          * for ftp service.
 254                          */
 255                         if (svc->port != FTPPORT)
 256                                 ct = ip_vs_conn_new(svc->af, iph.protocol,
 257                                                     &snet, 0,
 258                                                     &iph.daddr,
 259                                                     ports[1],
 260                                                     &dest->addr, dest->port,
 261                                                     IP_VS_CONN_F_TEMPLATE,
 262                                                     dest);
 263                         else
 264                                 ct = ip_vs_conn_new(svc->af, iph.protocol,
 265                                                     &snet, 0,
 266                                                     &iph.daddr, 0,
 267                                                     &dest->addr, 0,
 268                                                     IP_VS_CONN_F_TEMPLATE,
 269                                                     dest);
 270                         if (ct == NULL)
 271                                 return NULL;
 272
 273                         ct->timeout = svc->timeout;
 274                 } else {
 275                         /* set destination with the found template */
 276                         dest = ct->dest;
 277                 }
 278                 dport = dest->port;
 279         } else {
 280                 /*
 281                  * Note: persistent fwmark-based services and persistent
 282                  * port zero service are handled here.
 283                  * fwmark template: <IPPROTO_IP,caddr,0,fwmark,0,daddr,0>
 284                  * port zero template: <protocol,caddr,0,vaddr,0,daddr,0>
 285                  */
 286                 if (svc->fwmark) {
 287                         union nf_inet_addr fwmark = {
 288                                 .ip = htonl(svc->fwmark)
 289                         };
 290
 291                         ct = ip_vs_ct_in_get(svc->af, IPPROTO_IP, &snet, 0,
 292                                              &fwmark, 0);
 293                 } else
 294                         ct = ip_vs_ct_in_get(svc->af, iph.protocol, &snet, 0,
 295                                              &iph.daddr, 0);
 296
 297                 if (!ct || !ip_vs_check_template(ct)) {
 298                         /*
 299                          * If it is not persistent port zero, return NULL,
 300                          * otherwise create a connection template.
 301                          */
 302                         if (svc->port)
 303                                 return NULL;
 304
 305                         dest = svc->scheduler->schedule(svc, skb);
 306                         if (dest == NULL) {
 307                                 IP_VS_DBG(1, "p-schedule: no dest found.\n");
 308                                 return NULL;
 309                         }
 310
 311                         /*
 312                          * Create a template according to the service
 313                          */
 314                         if (svc->fwmark) {
 315                                 union nf_inet_addr fwmark = {
 316                                         .ip = htonl(svc->fwmark)
 317                                 };
 318
 319                                 ct = ip_vs_conn_new(svc->af, IPPROTO_IP,
 320                                                     &snet, 0,
 321                                                     &fwmark, 0,
 322                                                     &dest->addr, 0,
 323                                                     IP_VS_CONN_F_TEMPLATE,
 324                                                     dest);
 325                         } else
 326                                 ct = ip_vs_conn_new(svc->af, iph.protocol,
 327                                                     &snet, 0,
 328                                                     &iph.daddr, 0,
 329                                                     &dest->addr, 0,
 330                                                     IP_VS_CONN_F_TEMPLATE,
 331                                                     dest);
 332                         if (ct == NULL)
 333                                 return NULL;
 334
 335                         ct->timeout = svc->timeout;
 336                 } else {
 337                         /* set destination with the found template */
 338                         dest = ct->dest;
 339                 }
 340                 dport = ports[1];
 341         }
 342
 343         flags = (svc->flags & IP_VS_SVC_F_ONEPACKET
 344                  && iph.protocol == IPPROTO_UDP)?
 345                 IP_VS_CONN_F_ONE_PACKET : 0;
 346
 347         /*
 348          *    Create a new connection according to the template
 349          */
 350         cp = ip_vs_conn_new(svc->af, iph.protocol,
 351                             &iph.saddr, ports[0],
 352                             &iph.daddr, ports[1],
 353                             &dest->addr, dport,
 354                             flags,
 355                             dest);
 356         if (cp == NULL) {
 357                 ip_vs_conn_put(ct);
 358                 return NULL;
 359         }
 360
 361         /*
 362          *    Add its control
 363          */
 364         ip_vs_control_add(cp, ct);
 365         ip_vs_conn_put(ct);
 366
 367         ip_vs_conn_stats(cp, svc);
 368         return cp;
 369 }
 370
 371
 372 /*
 373  *  IPVS main scheduling function
 374  *  It selects a server according to the virtual service, and
 375  *  creates a connection entry.
 376  *  Protocols supported: TCP, UDP
 377  */
 378 struct ip_vs_conn *
 379 ip_vs_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
 380 {
 381         struct ip_vs_conn *cp = NULL;
 382         struct ip_vs_iphdr iph;
 383         struct ip_vs_dest *dest;
 384         __be16 _ports[2], *pptr, flags;
 385
 386         ip_vs_fill_iphdr(svc->af, skb_network_header(skb), &iph);
 387         pptr = skb_header_pointer(skb, iph.len, sizeof(_ports), _ports);
 388         if (pptr == NULL)
 389                 return NULL;
 390
 391         /*
 392          *    Persistent service
 393          */
 394         if (svc->flags & IP_VS_SVC_F_PERSISTENT)
 395                 return ip_vs_sched_persist(svc, skb, pptr);
 396
 397         /*
 398          *    Non-persistent service
 399          */
 400         if (!svc->fwmark && pptr[1] != svc->port) {
 401                 if (!svc->port)
 402                         pr_err("Schedule: port zero only supported "
 403                                "in persistent services, "
 404                                "check your ipvs configuration\n");
 405                 return NULL;
 406         }
 407
 408         dest = svc->scheduler->schedule(svc, skb);
 409         if (dest == NULL) {
 410                 IP_VS_DBG(1, "Schedule: no dest found.\n");
 411                 return NULL;
 412         }
 413
 414         flags = (svc->flags & IP_VS_SVC_F_ONEPACKET
 415                  && iph.protocol == IPPROTO_UDP)?
 416                 IP_VS_CONN_F_ONE_PACKET : 0;
 417
 418         /*
 419          *    Create a connection entry.
 420          */
 421         cp = ip_vs_conn_new(svc->af, iph.protocol,
 422                             &iph.saddr, pptr[0],
 423                             &iph.daddr, pptr[1],
 424                             &dest->addr, dest->port ? dest->port : pptr[1],
 425                             flags,
 426                             dest);
 427         if (cp == NULL)
 428                 return NULL;
 429
 430         IP_VS_DBG_BUF(6, "Schedule fwd:%c c:%s:%u v:%s:%u "
 431                       "d:%s:%u conn->flags:%X conn->refcnt:%d\n",
 432                       ip_vs_fwd_tag(cp),
 433                       IP_VS_DBG_ADDR(svc->af, &cp->caddr), ntohs(cp->cport),
 434                       IP_VS_DBG_ADDR(svc->af, &cp->vaddr), ntohs(cp->vport),
 435                       IP_VS_DBG_ADDR(svc->af, &cp->daddr), ntohs(cp->dport),
 436                       cp->flags, atomic_read(&cp->refcnt));
 437
 438         ip_vs_conn_stats(cp, svc);
 439         return cp;
 440 }
 441
 442
 443 /*
 444  *  Pass or drop the packet.
 445  *  Called by ip_vs_in, when the virtual service is available but
 446  *  no destination is available for a new connection.
 447  */
 448 int ip_vs_leave(struct ip_vs_service *svc, struct sk_buff *skb,
 449                 struct ip_vs_protocol *pp)
 450 {
 451         __be16 _ports[2], *pptr;
 452         struct ip_vs_iphdr iph;
 453         int unicast;
 454         ip_vs_fill_iphdr(svc->af, skb_network_header(skb), &iph);
 455
 456         pptr = skb_header_pointer(skb, iph.len, sizeof(_ports), _ports);
 457         if (pptr == NULL) {
 458                 ip_vs_service_put(svc);
 459                 return NF_DROP;
 460         }
 461
 462 #ifdef CONFIG_IP_VS_IPV6
 463         if (svc->af == AF_INET6)
 464                 unicast = ipv6_addr_type(&iph.daddr.in6) & IPV6_ADDR_UNICAST;
 465         else
 466 #endif
 467                 unicast = (inet_addr_type(&init_net, iph.daddr.ip) == RTN_UNICAST);
 468
 469         /* if it is fwmark-based service, the cache_bypass sysctl is up
 470            and the destination is a non-local unicast, then create
 471            a cache_bypass connection entry */
 472         if (sysctl_ip_vs_cache_bypass && svc->fwmark && unicast) {
 473                 int ret, cs;
 474                 struct ip_vs_conn *cp;
 475                 __u16 flags = (svc->flags & IP_VS_SVC_F_ONEPACKET &&
 476                                 iph.protocol == IPPROTO_UDP)?
 477                                 IP_VS_CONN_F_ONE_PACKET : 0;
 478                 union nf_inet_addr daddr =  { .all = { 0, 0, 0, 0 } };
 479
 480                 ip_vs_service_put(svc);
 481
 482                 /* create a new connection entry */
 483                 IP_VS_DBG(6, "%s(): create a cache_bypass entry\n", __func__);
 484                 cp = ip_vs_conn_new(svc->af, iph.protocol,
 485                                     &iph.saddr, pptr[0],
 486                                     &iph.daddr, pptr[1],
 487                                     &daddr, 0,
 488                                     IP_VS_CONN_F_BYPASS | flags,
 489                                     NULL);
 490                 if (cp == NULL)
 491                         return NF_DROP;
 492
 493                 /* statistics */
 494                 ip_vs_in_stats(cp, skb);
 495
 496                 /* set state */
 497                 cs = ip_vs_set_state(cp, IP_VS_DIR_INPUT, skb, pp);
 498
 499                 /* transmit the first SYN packet */
 500                 ret = cp->packet_xmit(skb, cp, pp);
 501                 /* do not touch skb anymore */
 502
 503                 atomic_inc(&cp->in_pkts);
 504                 ip_vs_conn_put(cp);
 505                 return ret;
 506         }
 507
 508         /*
 509          * When the virtual ftp service is presented, packets destined
 510          * for other services on the VIP may get here (except services
 511          * listed in the ipvs table), pass the packets, because it is
 512          * not ipvs job to decide to drop the packets.
 513          */
 514         if ((svc->port == FTPPORT) && (pptr[1] != FTPPORT)) {
 515                 ip_vs_service_put(svc);
 516                 return NF_ACCEPT;
 517         }
 518
 519         ip_vs_service_put(svc);
 520
 521         /*
 522          * Notify the client that the destination is unreachable, and
 523          * release the socket buffer.
 524          * Since it is in IP layer, the TCP socket is not actually
 525          * created, the TCP RST packet cannot be sent, instead that
 526          * ICMP_PORT_UNREACH is sent here no matter it is TCP/UDP. --WZ
 527          */
 528 #ifdef CONFIG_IP_VS_IPV6
 529         if (svc->af == AF_INET6)
 530                 icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
 531         else
 532 #endif
 533                 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
 534
 535         return NF_DROP;
 536 }
 537
 538 __sum16 ip_vs_checksum_complete(struct sk_buff *skb, int offset)
 539 {
 540         return csum_fold(skb_checksum(skb, offset, skb->len - offset, 0));
 541 }
 542
 543 static inline int ip_vs_gather_frags(struct sk_buff *skb, u_int32_t user)
 544 {
 545         int err = ip_defrag(skb, user);
 546
 547         if (!err)
 548                 ip_send_check(ip_hdr(skb));
 549
 550         return err;
 551 }
 552
 553 #ifdef CONFIG_IP_VS_IPV6
 554 static inline int ip_vs_gather_frags_v6(struct sk_buff *skb, u_int32_t user)
 555 {
 556         /* TODO IPv6: Find out what to do here for IPv6 */
 557         return 0;
 558 }
 559 #endif
 560
 561 /*
 562  * Packet has been made sufficiently writable in caller
 563  * - inout: 1=in->out, 0=out->in
 564  */
 565 void ip_vs_nat_icmp(struct sk_buff *skb, struct ip_vs_protocol *pp,
 566                     struct ip_vs_conn *cp, int inout)
 567 {
 568         struct iphdr *iph        = ip_hdr(skb);
 569         unsigned int icmp_offset = iph->ihl*4;
 570         struct icmphdr *icmph    = (struct icmphdr *)(skb_network_header(skb) +
 571                                                       icmp_offset);
 572         struct iphdr *ciph       = (struct iphdr *)(icmph + 1);
 573
 574         if (inout) {
 575                 iph->saddr = cp->vaddr.ip;
 576                 ip_send_check(iph);
 577                 ciph->daddr = cp->vaddr.ip;
 578                 ip_send_check(ciph);
 579         } else {
 580                 iph->daddr = cp->daddr.ip;
 581                 ip_send_check(iph);
 582                 ciph->saddr = cp->daddr.ip;
 583                 ip_send_check(ciph);
 584         }
 585
 586         /* the TCP/UDP/SCTP port */
 587         if (IPPROTO_TCP == ciph->protocol || IPPROTO_UDP == ciph->protocol ||
 588             IPPROTO_SCTP == ciph->protocol) {
 589                 __be16 *ports = (void *)ciph + ciph->ihl*4;
 590
 591                 if (inout)
 592                         ports[1] = cp->vport;
 593                 else
 594                         ports[0] = cp->dport;
 595         }
 596
 597         /* And finally the ICMP checksum */
 598         icmph->checksum = 0;
 599         icmph->checksum = ip_vs_checksum_complete(skb, icmp_offset);
 600         skb->ip_summed = CHECKSUM_UNNECESSARY;
 601
 602         if (inout)
 603                 IP_VS_DBG_PKT(11, pp, skb, (void *)ciph - (void *)iph,
 604                         "Forwarding altered outgoing ICMP");
 605         else
 606                 IP_VS_DBG_PKT(11, pp, skb, (void *)ciph - (void *)iph,
 607                         "Forwarding altered incoming ICMP");
 608 }
 609
 610 #ifdef CONFIG_IP_VS_IPV6
 611 void ip_vs_nat_icmp_v6(struct sk_buff *skb, struct ip_vs_protocol *pp,
 612                     struct ip_vs_conn *cp, int inout)
 613 {
 614         struct ipv6hdr *iph      = ipv6_hdr(skb);
 615         unsigned int icmp_offset = sizeof(struct ipv6hdr);
 616         struct icmp6hdr *icmph   = (struct icmp6hdr *)(skb_network_header(skb) +
 617                                                       icmp_offset);
 618         struct ipv6hdr *ciph     = (struct ipv6hdr *)(icmph + 1);
 619
 620         if (inout) {
 621                 iph->saddr = cp->vaddr.in6;
 622                 ciph->daddr = cp->vaddr.in6;
 623         } else {
 624                 iph->daddr = cp->daddr.in6;
 625                 ciph->saddr = cp->daddr.in6;
 626         }
 627
 628         /* the TCP/UDP/SCTP port */
 629         if (IPPROTO_TCP == ciph->nexthdr || IPPROTO_UDP == ciph->nexthdr ||
 630             IPPROTO_SCTP == ciph->nexthdr) {
 631                 __be16 *ports = (void *)ciph + sizeof(struct ipv6hdr);
 632
 633                 if (inout)
 634                         ports[1] = cp->vport;
 635                 else
 636                         ports[0] = cp->dport;
 637         }
 638
 639         /* And finally the ICMP checksum */
 640         icmph->icmp6_cksum = 0;
 641         /* TODO IPv6: is this correct for ICMPv6? */
 642         ip_vs_checksum_complete(skb, icmp_offset);
 643         skb->ip_summed = CHECKSUM_UNNECESSARY;
 644
 645         if (inout)
 646                 IP_VS_DBG_PKT(11, pp, skb, (void *)ciph - (void *)iph,
 647                         "Forwarding altered outgoing ICMPv6");
 648         else
 649                 IP_VS_DBG_PKT(11, pp, skb, (void *)ciph - (void *)iph,
 650                         "Forwarding altered incoming ICMPv6");
 651 }
 652 #endif
 653
 654 /* Handle relevant response ICMP messages - forward to the right
 655  * destination host. Used for NAT and local client.
 656  */
 657 static int handle_response_icmp(int af, struct sk_buff *skb,
 658                                 union nf_inet_addr *snet,
 659                                 __u8 protocol, struct ip_vs_conn *cp,
 660                                 struct ip_vs_protocol *pp,
 661                                 unsigned int offset, unsigned int ihl)
 662 {
 663         unsigned int verdict = NF_DROP;
 664
 665         if (IP_VS_FWD_METHOD(cp) != 0) {
 666                 pr_err("shouldn't reach here, because the box is on the "
 667                        "half connection in the tun/dr module.\n");
 668         }
 669
 670         /* Ensure the checksum is correct */
 671         if (!skb_csum_unnecessary(skb) && ip_vs_checksum_complete(skb, ihl)) {
 672                 /* Failed checksum! */
 673                 IP_VS_DBG_BUF(1, "Forward ICMP: failed checksum from %s!\n",
 674                               IP_VS_DBG_ADDR(af, snet));
 675                 goto out;
 676         }
 677
 678         if (IPPROTO_TCP == protocol || IPPROTO_UDP == protocol ||
 679             IPPROTO_SCTP == protocol)
 680                 offset += 2 * sizeof(__u16);
 681         if (!skb_make_writable(skb, offset))
 682                 goto out;
 683
 684 #ifdef CONFIG_IP_VS_IPV6
 685         if (af == AF_INET6)
 686                 ip_vs_nat_icmp_v6(skb, pp, cp, 1);
 687         else
 688 #endif
 689                 ip_vs_nat_icmp(skb, pp, cp, 1);
 690
 691         /* do the statistics and put it back */
 692         ip_vs_out_stats(cp, skb);
 693
 694         skb->ipvs_property = 1;
 695         verdict = NF_ACCEPT;
 696
 697 out:
 698         __ip_vs_conn_put(cp);
 699
 700         return verdict;
 701 }
 702
 703 /*
 704  *      Handle ICMP messages in the inside-to-outside direction (outgoing).
 705  *      Find any that might be relevant, check against existing connections.
 706  *      Currently handles error types - unreachable, quench, ttl exceeded.
 707  */
 708 static int ip_vs_out_icmp(struct sk_buff *skb, int *related)
 709 {
 710         struct iphdr *iph;
 711         struct icmphdr  _icmph, *ic;
 712         struct iphdr    _ciph, *cih;    /* The ip header contained within the ICMP */
 713         struct ip_vs_iphdr ciph;
 714         struct ip_vs_conn *cp;
 715         struct ip_vs_protocol *pp;
 716         unsigned int offset, ihl;
 717         union nf_inet_addr snet;
 718
 719         *related = 1;
 720
 721         /* reassemble IP fragments */
 722         if (ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET)) {
 723                 if (ip_vs_gather_frags(skb, IP_DEFRAG_VS_OUT))
 724                         return NF_STOLEN;
 725         }
 726
 727         iph = ip_hdr(skb);
 728         offset = ihl = iph->ihl * 4;
 729         ic = skb_header_pointer(skb, offset, sizeof(_icmph), &_icmph);
 730         if (ic == NULL)
 731                 return NF_DROP;
 732
 733         IP_VS_DBG(12, "Outgoing ICMP (%d,%d) %pI4->%pI4\n",
 734                   ic->type, ntohs(icmp_id(ic)),
 735                   &iph->saddr, &iph->daddr);
 736
 737         /*
 738          * Work through seeing if this is for us.
 739          * These checks are supposed to be in an order that means easy
 740          * things are checked first to speed up processing.... however
 741          * this means that some packets will manage to get a long way
 742          * down this stack and then be rejected, but that's life.
 743          */
 744         if ((ic->type != ICMP_DEST_UNREACH) &&
 745             (ic->type != ICMP_SOURCE_QUENCH) &&
 746             (ic->type != ICMP_TIME_EXCEEDED)) {
 747                 *related = 0;
 748                 return NF_ACCEPT;
 749         }
 750
 751         /* Now find the contained IP header */
 752         offset += sizeof(_icmph);
 753         cih = skb_header_pointer(skb, offset, sizeof(_ciph), &_ciph);
 754         if (cih == NULL)
 755                 return NF_ACCEPT; /* The packet looks wrong, ignore */
 756
 757         pp = ip_vs_proto_get(cih->protocol);
 758         if (!pp)
 759                 return NF_ACCEPT;
 760
 761         /* Is the embedded protocol header present? */
 762         if (unlikely(cih->frag_off & htons(IP_OFFSET) &&
 763                      pp->dont_defrag))
 764                 return NF_ACCEPT;
 765
 766         IP_VS_DBG_PKT(11, pp, skb, offset, "Checking outgoing ICMP for");
 767
 768         offset += cih->ihl * 4;
 769
 770         ip_vs_fill_iphdr(AF_INET, cih, &ciph);
 771         /* The embedded headers contain source and dest in reverse order */
 772         cp = pp->conn_out_get(AF_INET, skb, pp, &ciph, offset, 1);
 773         if (!cp)
 774                 return NF_ACCEPT;
 775
 776         snet.ip = iph->saddr;
 777         return handle_response_icmp(AF_INET, skb, &snet, cih->protocol, cp,
 778                                     pp, offset, ihl);
 779 }
 780
 781 #ifdef CONFIG_IP_VS_IPV6
 782 static int ip_vs_out_icmp_v6(struct sk_buff *skb, int *related)
 783 {
 784         struct ipv6hdr *iph;
 785         struct icmp6hdr _icmph, *ic;
 786         struct ipv6hdr  _ciph, *cih;    /* The ip header contained
 787                                            within the ICMP */
 788         struct ip_vs_iphdr ciph;
 789         struct ip_vs_conn *cp;
 790         struct ip_vs_protocol *pp;
 791         unsigned int offset;
 792         union nf_inet_addr snet;
 793
 794         *related = 1;
 795
 796         /* reassemble IP fragments */
 797         if (ipv6_hdr(skb)->nexthdr == IPPROTO_FRAGMENT) {
 798                 if (ip_vs_gather_frags_v6(skb, IP_DEFRAG_VS_OUT))
 799                         return NF_STOLEN;
 800         }
 801
 802         iph = ipv6_hdr(skb);
 803         offset = sizeof(struct ipv6hdr);
 804         ic = skb_header_pointer(skb, offset, sizeof(_icmph), &_icmph);
 805         if (ic == NULL)
 806                 return NF_DROP;
 807
 808         IP_VS_DBG(12, "Outgoing ICMPv6 (%d,%d) %pI6->%pI6\n",
 809                   ic->icmp6_type, ntohs(icmpv6_id(ic)),
 810                   &iph->saddr, &iph->daddr);
 811
 812         /*
 813          * Work through seeing if this is for us.
 814          * These checks are supposed to be in an order that means easy
 815          * things are checked first to speed up processing.... however
 816          * this means that some packets will manage to get a long way
 817          * down this stack and then be rejected, but that's life.
 818          */
 819         if ((ic->icmp6_type != ICMPV6_DEST_UNREACH) &&
 820             (ic->icmp6_type != ICMPV6_PKT_TOOBIG) &&
 821             (ic->icmp6_type != ICMPV6_TIME_EXCEED)) {
 822                 *related = 0;
 823                 return NF_ACCEPT;
 824         }
 825
 826         /* Now find the contained IP header */
 827         offset += sizeof(_icmph);
 828         cih = skb_header_pointer(skb, offset, sizeof(_ciph), &_ciph);
 829         if (cih == NULL)
 830                 return NF_ACCEPT; /* The packet looks wrong, ignore */
 831
 832         pp = ip_vs_proto_get(cih->nexthdr);
 833         if (!pp)
 834                 return NF_ACCEPT;
 835
 836         /* Is the embedded protocol header present? */
 837         /* TODO: we don't support fragmentation at the moment anyways */
 838         if (unlikely(cih->nexthdr == IPPROTO_FRAGMENT && pp->dont_defrag))
 839                 return NF_ACCEPT;
 840
 841         IP_VS_DBG_PKT(11, pp, skb, offset, "Checking outgoing ICMPv6 for");
 842
 843         offset += sizeof(struct ipv6hdr);
 844
 845         ip_vs_fill_iphdr(AF_INET6, cih, &ciph);
 846         /* The embedded headers contain source and dest in reverse order */
 847         cp = pp->conn_out_get(AF_INET6, skb, pp, &ciph, offset, 1);
 848         if (!cp)
 849                 return NF_ACCEPT;
 850
 851         ipv6_addr_copy(&snet.in6, &iph->saddr);
 852         return handle_response_icmp(AF_INET6, skb, &snet, cih->nexthdr, cp,
 853                                     pp, offset, sizeof(struct ipv6hdr));
 854 }
 855 #endif
 856
 857 /*
 858  * Check if sctp chunc is ABORT chunk
 859  */
 860 static inline int is_sctp_abort(const struct sk_buff *skb, int nh_len)
 861 {
 862         sctp_chunkhdr_t *sch, schunk;
 863         sch = skb_header_pointer(skb, nh_len + sizeof(sctp_sctphdr_t),
 864                         sizeof(schunk), &schunk);
 865         if (sch == NULL)
 866                 return 0;
 867         if (sch->type == SCTP_CID_ABORT)
 868                 return 1;
 869         return 0;
 870 }
 871
 872 static inline int is_tcp_reset(const struct sk_buff *skb, int nh_len)
 873 {
 874         struct tcphdr _tcph, *th;
 875
 876         th = skb_header_pointer(skb, nh_len, sizeof(_tcph), &_tcph);
 877         if (th == NULL)
 878                 return 0;
 879         return th->rst;
 880 }
 881
 882 /* Handle response packets: rewrite addresses and send away...
 883  * Used for NAT and local client.
 884  */
 885 static unsigned int
 886 handle_response(int af, struct sk_buff *skb, struct ip_vs_protocol *pp,
 887                 struct ip_vs_conn *cp, int ihl)
 888 {
 889         IP_VS_DBG_PKT(11, pp, skb, 0, "Outgoing packet");
 890
 891         if (!skb_make_writable(skb, ihl))
 892                 goto drop;
 893
 894         /* mangle the packet */
 895         if (pp->snat_handler && !pp->snat_handler(skb, pp, cp))
 896                 goto drop;
 897
 898 #ifdef CONFIG_IP_VS_IPV6
 899         if (af == AF_INET6)
 900                 ipv6_hdr(skb)->saddr = cp->vaddr.in6;
 901         else
 902 #endif
 903         {
 904                 ip_hdr(skb)->saddr = cp->vaddr.ip;
 905                 ip_send_check(ip_hdr(skb));
 906         }
 907
 908         /* For policy routing, packets originating from this
 909          * machine itself may be routed differently to packets
 910          * passing through.  We want this packet to be routed as
 911          * if it came from this machine itself.  So re-compute
 912          * the routing information.
 913          */
 914 #ifdef CONFIG_IP_VS_IPV6
 915         if (af == AF_INET6) {
 916                 if (ip6_route_me_harder(skb) != 0)
 917                         goto drop;
 918         } else
 919 #endif
 920                 if (ip_route_me_harder(skb, RTN_LOCAL) != 0)
 921                         goto drop;
 922
 923         IP_VS_DBG_PKT(10, pp, skb, 0, "After SNAT");
 924
 925         ip_vs_out_stats(cp, skb);
 926         ip_vs_set_state(cp, IP_VS_DIR_OUTPUT, skb, pp);
 927         ip_vs_conn_put(cp);
 928
 929         skb->ipvs_property = 1;
 930
 931         LeaveFunction(11);
 932         return NF_ACCEPT;
 933
 934 drop:
 935         ip_vs_conn_put(cp);
 936         kfree_skb(skb);
 937         return NF_STOLEN;
 938 }
 939
 940 /*
 941  *      It is hooked at the NF_INET_FORWARD chain, used only for VS/NAT.
 942  *      Check if outgoing packet belongs to the established ip_vs_conn.
 943  */
 944 static unsigned int
 945 ip_vs_out(unsigned int hooknum, struct sk_buff *skb,
 946           const struct net_device *in, const struct net_device *out,
 947           int (*okfn)(struct sk_buff *))
 948 {
 949         struct ip_vs_iphdr iph;
 950         struct ip_vs_protocol *pp;
 951         struct ip_vs_conn *cp;
 952         int af;
 953
 954         EnterFunction(11);
 955
 956         af = (skb->protocol == htons(ETH_P_IP)) ? AF_INET : AF_INET6;
 957
 958         if (skb->ipvs_property)
 959                 return NF_ACCEPT;
 960
 961         ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
 962 #ifdef CONFIG_IP_VS_IPV6
 963         if (af == AF_INET6) {
 964                 if (unlikely(iph.protocol == IPPROTO_ICMPV6)) {
 965                         int related, verdict = ip_vs_out_icmp_v6(skb, &related);
 966
 967                         if (related)
 968                                 return verdict;
 969                         ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
 970                 }
 971         } else
 972 #endif
 973                 if (unlikely(iph.protocol == IPPROTO_ICMP)) {
 974                         int related, verdict = ip_vs_out_icmp(skb, &related);
 975
 976                         if (related)
 977                                 return verdict;
 978                         ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
 979                 }
 980
 981         pp = ip_vs_proto_get(iph.protocol);
 982         if (unlikely(!pp))
 983                 return NF_ACCEPT;
 984
 985         /* reassemble IP fragments */
 986 #ifdef CONFIG_IP_VS_IPV6
 987         if (af == AF_INET6) {
 988                 if (unlikely(iph.protocol == IPPROTO_ICMPV6)) {
 989                         int related, verdict = ip_vs_out_icmp_v6(skb, &related);
 990
 991                         if (related)
 992                                 return verdict;
 993
 994                         ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
 995                 }
 996         } else
 997 #endif
 998                 if (unlikely(ip_hdr(skb)->frag_off & htons(IP_MF|IP_OFFSET) &&
 999                              !pp->dont_defrag)) {
1000                         if (ip_vs_gather_frags(skb, IP_DEFRAG_VS_OUT))
1001                                 return NF_STOLEN;
1002
1003                         ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
1004                 }
1005
1006         /*
1007          * Check if the packet belongs to an existing entry
1008          */
1009         cp = pp->conn_out_get(af, skb, pp, &iph, iph.len, 0);
1010
1011         if (unlikely(!cp)) {
1012                 if (sysctl_ip_vs_nat_icmp_send &&
1013                     (pp->protocol == IPPROTO_TCP ||
1014                      pp->protocol == IPPROTO_UDP ||
1015                      pp->protocol == IPPROTO_SCTP)) {
1016                         __be16 _ports[2], *pptr;
1017
1018                         pptr = skb_header_pointer(skb, iph.len,
1019                                                   sizeof(_ports), _ports);
1020                         if (pptr == NULL)
1021                                 return NF_ACCEPT;       /* Not for me */
1022                         if (ip_vs_lookup_real_service(af, iph.protocol,
1023                                                       &iph.saddr,
1024                                                       pptr[0])) {
1025                                 /*
1026                                  * Notify the real server: there is no
1027                                  * existing entry if it is not RST
1028                                  * packet or not TCP packet.
1029                                  */
1030                                 if ((iph.protocol != IPPROTO_TCP &&
1031                                      iph.protocol != IPPROTO_SCTP)
1032                                      || ((iph.protocol == IPPROTO_TCP
1033                                           && !is_tcp_reset(skb, iph.len))
1034                                          || (iph.protocol == IPPROTO_SCTP
1035                                                 && !is_sctp_abort(skb,
1036                                                         iph.len)))) {
1037 #ifdef CONFIG_IP_VS_IPV6
1038                                         if (af == AF_INET6)
1039                                                 icmpv6_send(skb,
1040                                                             ICMPV6_DEST_UNREACH,
1041                                                             ICMPV6_PORT_UNREACH,
1042                                                             0);
1043                                         else
1044 #endif
1045                                                 icmp_send(skb,
1046                                                           ICMP_DEST_UNREACH,
1047                                                           ICMP_PORT_UNREACH, 0);
1048                                         return NF_DROP;
1049                                 }
1050                         }
1051                 }
1052                 IP_VS_DBG_PKT(12, pp, skb, 0,
1053                               "packet continues traversal as normal");
1054                 return NF_ACCEPT;
1055         }
1056
1057         return handle_response(af, skb, pp, cp, iph.len);
1058 }
1059
1060
1061 /*
1062  *      Handle ICMP messages in the outside-to-inside direction (incoming).
1063  *      Find any that might be relevant, check against existing connections,
1064  *      forward to the right destination host if relevant.
1065  *      Currently handles error types - unreachable, quench, ttl exceeded.
1066  */
1067 static int
1068 ip_vs_in_icmp(struct sk_buff *skb, int *related, unsigned int hooknum)
1069 {
1070         struct iphdr *iph;
1071         struct icmphdr  _icmph, *ic;
1072         struct iphdr    _ciph, *cih;    /* The ip header contained within the ICMP */
1073         struct ip_vs_iphdr ciph;
1074         struct ip_vs_conn *cp;
1075         struct ip_vs_protocol *pp;
1076         unsigned int offset, ihl, verdict;
1077         union nf_inet_addr snet;
1078
1079         *related = 1;
1080
1081         /* reassemble IP fragments */
1082         if (ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET)) {
1083                 if (ip_vs_gather_frags(skb, hooknum == NF_INET_LOCAL_IN ?
1084                                             IP_DEFRAG_VS_IN : IP_DEFRAG_VS_FWD))
1085                         return NF_STOLEN;
1086         }
1087
1088         iph = ip_hdr(skb);
1089         offset = ihl = iph->ihl * 4;
1090         ic = skb_header_pointer(skb, offset, sizeof(_icmph), &_icmph);
1091         if (ic == NULL)
1092                 return NF_DROP;
1093
1094         IP_VS_DBG(12, "Incoming ICMP (%d,%d) %pI4->%pI4\n",
1095                   ic->type, ntohs(icmp_id(ic)),
1096                   &iph->saddr, &iph->daddr);
1097
1098         /*
1099          * Work through seeing if this is for us.
1100          * These checks are supposed to be in an order that means easy
1101          * things are checked first to speed up processing.... however
1102          * this means that some packets will manage to get a long way
1103          * down this stack and then be rejected, but that's life.
1104          */
1105         if ((ic->type != ICMP_DEST_UNREACH) &&
1106             (ic->type != ICMP_SOURCE_QUENCH) &&
1107             (ic->type != ICMP_TIME_EXCEEDED)) {
1108                 *related = 0;
1109                 return NF_ACCEPT;
1110         }
1111
1112         /* Now find the contained IP header */
1113         offset += sizeof(_icmph);
1114         cih = skb_header_pointer(skb, offset, sizeof(_ciph), &_ciph);
1115         if (cih == NULL)
1116                 return NF_ACCEPT; /* The packet looks wrong, ignore */
1117
1118         pp = ip_vs_proto_get(cih->protocol);
1119         if (!pp)
1120                 return NF_ACCEPT;
1121
1122         /* Is the embedded protocol header present? */
1123         if (unlikely(cih->frag_off & htons(IP_OFFSET) &&
1124                      pp->dont_defrag))
1125                 return NF_ACCEPT;
1126
1127         IP_VS_DBG_PKT(11, pp, skb, offset, "Checking incoming ICMP for");
1128
1129         offset += cih->ihl * 4;
1130
1131         ip_vs_fill_iphdr(AF_INET, cih, &ciph);
1132         /* The embedded headers contain source and dest in reverse order */
1133         cp = pp->conn_in_get(AF_INET, skb, pp, &ciph, offset, 1);
1134         if (!cp) {
1135                 /* The packet could also belong to a local client */
1136                 cp = pp->conn_out_get(AF_INET, skb, pp, &ciph, offset, 1);
1137                 if (cp) {
1138                         snet.ip = iph->saddr;
1139                         return handle_response_icmp(AF_INET, skb, &snet,
1140                                                     cih->protocol, cp, pp,
1141                                                     offset, ihl);
1142                 }
1143                 return NF_ACCEPT;
1144         }
1145
1146         verdict = NF_DROP;
1147
1148         /* Ensure the checksum is correct */
1149         if (!skb_csum_unnecessary(skb) && ip_vs_checksum_complete(skb, ihl)) {
1150                 /* Failed checksum! */
1151                 IP_VS_DBG(1, "Incoming ICMP: failed checksum from %pI4!\n",
1152                           &iph->saddr);
1153                 goto out;
1154         }
1155
1156         /* do the statistics and put it back */
1157         ip_vs_in_stats(cp, skb);
1158         if (IPPROTO_TCP == cih->protocol || IPPROTO_UDP == cih->protocol)
1159                 offset += 2 * sizeof(__u16);
1160         verdict = ip_vs_icmp_xmit(skb, cp, pp, offset);
1161         /* do not touch skb anymore */
1162
1163   out:
1164         __ip_vs_conn_put(cp);
1165
1166         return verdict;
1167 }
1168
1169 #ifdef CONFIG_IP_VS_IPV6
1170 static int
1171 ip_vs_in_icmp_v6(struct sk_buff *skb, int *related, unsigned int hooknum)
1172 {
1173         struct ipv6hdr *iph;
1174         struct icmp6hdr _icmph, *ic;
1175         struct ipv6hdr  _ciph, *cih;    /* The ip header contained
1176                                            within the ICMP */
1177         struct ip_vs_iphdr ciph;
1178         struct ip_vs_conn *cp;
1179         struct ip_vs_protocol *pp;
1180         unsigned int offset, verdict;
1181         union nf_inet_addr snet;
1182
1183         *related = 1;
1184
1185         /* reassemble IP fragments */
1186         if (ipv6_hdr(skb)->nexthdr == IPPROTO_FRAGMENT) {
1187                 if (ip_vs_gather_frags_v6(skb, hooknum == NF_INET_LOCAL_IN ?
1188                                                IP_DEFRAG_VS_IN :
1189                                                IP_DEFRAG_VS_FWD))
1190                         return NF_STOLEN;
1191         }
1192
1193         iph = ipv6_hdr(skb);
1194         offset = sizeof(struct ipv6hdr);
1195         ic = skb_header_pointer(skb, offset, sizeof(_icmph), &_icmph);
1196         if (ic == NULL)
1197                 return NF_DROP;
1198
1199         IP_VS_DBG(12, "Incoming ICMPv6 (%d,%d) %pI6->%pI6\n",
1200                   ic->icmp6_type, ntohs(icmpv6_id(ic)),
1201                   &iph->saddr, &iph->daddr);
1202
1203         /*
1204          * Work through seeing if this is for us.
1205          * These checks are supposed to be in an order that means easy
1206          * things are checked first to speed up processing.... however
1207          * this means that some packets will manage to get a long way
1208          * down this stack and then be rejected, but that's life.
1209          */
1210         if ((ic->icmp6_type != ICMPV6_DEST_UNREACH) &&
1211             (ic->icmp6_type != ICMPV6_PKT_TOOBIG) &&
1212             (ic->icmp6_type != ICMPV6_TIME_EXCEED)) {
1213                 *related = 0;
1214                 return NF_ACCEPT;
1215         }
1216
1217         /* Now find the contained IP header */
1218         offset += sizeof(_icmph);
1219         cih = skb_header_pointer(skb, offset, sizeof(_ciph), &_ciph);
1220         if (cih == NULL)
1221                 return NF_ACCEPT; /* The packet looks wrong, ignore */
1222
1223         pp = ip_vs_proto_get(cih->nexthdr);
1224         if (!pp)
1225                 return NF_ACCEPT;
1226
1227         /* Is the embedded protocol header present? */
1228         /* TODO: we don't support fragmentation at the moment anyways */
1229         if (unlikely(cih->nexthdr == IPPROTO_FRAGMENT && pp->dont_defrag))
1230                 return NF_ACCEPT;
1231
1232         IP_VS_DBG_PKT(11, pp, skb, offset, "Checking incoming ICMPv6 for");
1233
1234         offset += sizeof(struct ipv6hdr);
1235
1236         ip_vs_fill_iphdr(AF_INET6, cih, &ciph);
1237         /* The embedded headers contain source and dest in reverse order */
1238         cp = pp->conn_in_get(AF_INET6, skb, pp, &ciph, offset, 1);
1239         if (!cp) {
1240                 /* The packet could also belong to a local client */
1241                 cp = pp->conn_out_get(AF_INET6, skb, pp, &ciph, offset, 1);
1242                 if (cp) {
1243                         ipv6_addr_copy(&snet.in6, &iph->saddr);
1244                         return handle_response_icmp(AF_INET6, skb, &snet,
1245                                                     cih->nexthdr,
1246                                                     cp, pp, offset,
1247                                                     sizeof(struct ipv6hdr));
1248                 }
1249                 return NF_ACCEPT;
1250         }
1251
1252         verdict = NF_DROP;
1253
1254         /* do the statistics and put it back */
1255         ip_vs_in_stats(cp, skb);
1256         if (IPPROTO_TCP == cih->nexthdr || IPPROTO_UDP == cih->nexthdr ||
1257             IPPROTO_SCTP == cih->nexthdr)
1258                 offset += 2 * sizeof(__u16);
1259         verdict = ip_vs_icmp_xmit_v6(skb, cp, pp, offset);
1260         /* do not touch skb anymore */
1261
1262         __ip_vs_conn_put(cp);
1263
1264         return verdict;
1265 }
1266 #endif
1267
1268
1269 /*
1270  *      Check if it's for virtual services, look it up,
1271  *      and send it on its way...
1272  */
1273 static unsigned int
1274 ip_vs_in(unsigned int hooknum, struct sk_buff *skb,
1275          const struct net_device *in, const struct net_device *out,
1276          int (*okfn)(struct sk_buff *))
1277 {
1278         struct ip_vs_iphdr iph;
1279         struct ip_vs_protocol *pp;
1280         struct ip_vs_conn *cp;
1281         int ret, restart, af, pkts;
1282
1283         af = (skb->protocol == htons(ETH_P_IP)) ? AF_INET : AF_INET6;
1284
1285         ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
1286
1287         /*
1288          *      Big tappo: only PACKET_HOST, including loopback for local client
1289          *      Don't handle local packets on IPv6 for now
1290          */
1291         if (unlikely(skb->pkt_type != PACKET_HOST)) {
1292                 IP_VS_DBG_BUF(12, "packet type=%d proto=%d daddr=%s ignored\n",
1293                               skb->pkt_type,
1294                               iph.protocol,
1295                               IP_VS_DBG_ADDR(af, &iph.daddr));
1296                 return NF_ACCEPT;
1297         }
1298
1299 #ifdef CONFIG_IP_VS_IPV6
1300         if (af == AF_INET6) {
1301                 if (unlikely(iph.protocol == IPPROTO_ICMPV6)) {
1302                         int related, verdict = ip_vs_in_icmp_v6(skb, &related, hooknum);
1303
1304                         if (related)
1305                                 return verdict;
1306                         ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
1307                 }
1308         } else
1309 #endif
1310                 if (unlikely(iph.protocol == IPPROTO_ICMP)) {
1311                         int related, verdict = ip_vs_in_icmp(skb, &related, hooknum);
1312
1313                         if (related)
1314                                 return verdict;
1315                         ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
1316                 }
1317
1318         /* Protocol supported? */
1319         pp = ip_vs_proto_get(iph.protocol);
1320         if (unlikely(!pp))
1321                 return NF_ACCEPT;
1322
1323         /*
1324          * Check if the packet belongs to an existing connection entry
1325          */
1326         cp = pp->conn_in_get(af, skb, pp, &iph, iph.len, 0);
1327
1328         if (unlikely(!cp)) {
1329                 int v;
1330
1331                 /* For local client packets, it could be a response */
1332                 cp = pp->conn_out_get(af, skb, pp, &iph, iph.len, 0);
1333                 if (cp)
1334                         return handle_response(af, skb, pp, cp, iph.len);
1335
1336                 if (!pp->conn_schedule(af, skb, pp, &v, &cp))
1337                         return v;
1338         }
1339
1340         if (unlikely(!cp)) {
1341                 /* sorry, all this trouble for a no-hit :) */
1342                 IP_VS_DBG_PKT(12, pp, skb, 0,
1343                               "packet continues traversal as normal");
1344                 return NF_ACCEPT;
1345         }
1346
1347         IP_VS_DBG_PKT(11, pp, skb, 0, "Incoming packet");
1348
1349         /* Check the server status */
1350         if (cp->dest && !(cp->dest->flags & IP_VS_DEST_F_AVAILABLE)) {
1351                 /* the destination server is not available */
1352
1353                 if (sysctl_ip_vs_expire_nodest_conn) {
1354                         /* try to expire the connection immediately */
1355                         ip_vs_conn_expire_now(cp);
1356                 }
1357                 /* don't restart its timer, and silently
1358                    drop the packet. */
1359                 __ip_vs_conn_put(cp);
1360                 return NF_DROP;
1361         }
1362
1363         ip_vs_in_stats(cp, skb);
1364         restart = ip_vs_set_state(cp, IP_VS_DIR_INPUT, skb, pp);
1365         if (cp->packet_xmit)
1366                 ret = cp->packet_xmit(skb, cp, pp);
1367                 /* do not touch skb anymore */
1368         else {
1369                 IP_VS_DBG_RL("warning: packet_xmit is null");
1370                 ret = NF_ACCEPT;
1371         }
1372
1373         /* Increase its packet counter and check if it is needed
1374          * to be synchronized
1375          *
1376          * Sync connection if it is about to close to
1377          * encorage the standby servers to update the connections timeout
1378          */
1379         pkts = atomic_add_return(1, &cp->in_pkts);
1380         if (af == AF_INET && (ip_vs_sync_state & IP_VS_STATE_MASTER) &&
1381             cp->protocol == IPPROTO_SCTP) {
1382                 if ((cp->state == IP_VS_SCTP_S_ESTABLISHED &&
1383                         (atomic_read(&cp->in_pkts) %
1384                          sysctl_ip_vs_sync_threshold[1]
1385                          == sysctl_ip_vs_sync_threshold[0])) ||
1386                                 (cp->old_state != cp->state &&
1387                                  ((cp->state == IP_VS_SCTP_S_CLOSED) ||
1388                                   (cp->state == IP_VS_SCTP_S_SHUT_ACK_CLI) ||
1389                                   (cp->state == IP_VS_SCTP_S_SHUT_ACK_SER)))) {
1390                         ip_vs_sync_conn(cp);
1391                         goto out;
1392                 }
1393         }
1394
1395         if (af == AF_INET &&
1396             (ip_vs_sync_state & IP_VS_STATE_MASTER) &&
1397             (((cp->protocol != IPPROTO_TCP ||
1398                cp->state == IP_VS_TCP_S_ESTABLISHED) &&
1399               (pkts % sysctl_ip_vs_sync_threshold[1]
1400                == sysctl_ip_vs_sync_threshold[0])) ||
1401              ((cp->protocol == IPPROTO_TCP) && (cp->old_state != cp->state) &&
1402               ((cp->state == IP_VS_TCP_S_FIN_WAIT) ||
1403                (cp->state == IP_VS_TCP_S_CLOSE) ||
1404                (cp->state == IP_VS_TCP_S_CLOSE_WAIT) ||
1405                (cp->state == IP_VS_TCP_S_TIME_WAIT)))))
1406                 ip_vs_sync_conn(cp);
1407 out:
1408         cp->old_state = cp->state;
1409
1410         ip_vs_conn_put(cp);
1411         return ret;
1412 }
1413
1414
1415 /*
1416  *      It is hooked at the NF_INET_FORWARD chain, in order to catch ICMP
1417  *      related packets destined for 0.0.0.0/0.
1418  *      When fwmark-based virtual service is used, such as transparent
1419  *      cache cluster, TCP packets can be marked and routed to ip_vs_in,
1420  *      but ICMP destined for 0.0.0.0/0 cannot not be easily marked and
1421  *      sent to ip_vs_in_icmp. So, catch them at the NF_INET_FORWARD chain
1422  *      and send them to ip_vs_in_icmp.
1423  */
1424 static unsigned int
1425 ip_vs_forward_icmp(unsigned int hooknum, struct sk_buff *skb,
1426                    const struct net_device *in, const struct net_device *out,
1427                    int (*okfn)(struct sk_buff *))
1428 {
1429         int r;
1430
1431         if (ip_hdr(skb)->protocol != IPPROTO_ICMP)
1432                 return NF_ACCEPT;
1433
1434         return ip_vs_in_icmp(skb, &r, hooknum);
1435 }
1436
1437 #ifdef CONFIG_IP_VS_IPV6
1438 static unsigned int
1439 ip_vs_forward_icmp_v6(unsigned int hooknum, struct sk_buff *skb,
1440                       const struct net_device *in, const struct net_device *out,
1441                       int (*okfn)(struct sk_buff *))
1442 {
1443         int r;
1444
1445         if (ipv6_hdr(skb)->nexthdr != IPPROTO_ICMPV6)
1446                 return NF_ACCEPT;
1447
1448         return ip_vs_in_icmp_v6(skb, &r, hooknum);
1449 }
1450 #endif
1451
1452
1453 static struct nf_hook_ops ip_vs_ops[] __read_mostly = {
1454         /* After packet filtering, forward packet through VS/DR, VS/TUN,
1455          * or VS/NAT(change destination), so that filtering rules can be
1456          * applied to IPVS. */
1457         {
1458                 .hook           = ip_vs_in,
1459                 .owner          = THIS_MODULE,
1460                 .pf             = PF_INET,
1461                 .hooknum        = NF_INET_LOCAL_IN,
1462                 .priority       = 100,
1463         },
1464         /* After packet filtering, change source only for VS/NAT */
1465         {
1466                 .hook           = ip_vs_out,
1467                 .owner          = THIS_MODULE,
1468                 .pf             = PF_INET,
1469                 .hooknum        = NF_INET_FORWARD,
1470                 .priority       = 100,
1471         },
1472         /* After packet filtering (but before ip_vs_out_icmp), catch icmp
1473          * destined for 0.0.0.0/0, which is for incoming IPVS connections */
1474         {
1475                 .hook           = ip_vs_forward_icmp,
1476                 .owner          = THIS_MODULE,
1477                 .pf             = PF_INET,
1478                 .hooknum        = NF_INET_FORWARD,
1479                 .priority       = 99,
1480         },
1481 #ifdef CONFIG_IP_VS_IPV6
1482         /* After packet filtering, forward packet through VS/DR, VS/TUN,
1483          * or VS/NAT(change destination), so that filtering rules can be
1484          * applied to IPVS. */
1485         {
1486                 .hook           = ip_vs_in,
1487                 .owner          = THIS_MODULE,
1488                 .pf             = PF_INET6,
1489                 .hooknum        = NF_INET_LOCAL_IN,
1490                 .priority       = 100,
1491         },
1492         /* After packet filtering, change source only for VS/NAT */
1493         {
1494                 .hook           = ip_vs_out,
1495                 .owner          = THIS_MODULE,
1496                 .pf             = PF_INET6,
1497                 .hooknum        = NF_INET_FORWARD,
1498                 .priority       = 100,
1499         },
1500         /* After packet filtering (but before ip_vs_out_icmp), catch icmp
1501          * destined for 0.0.0.0/0, which is for incoming IPVS connections */
1502         {
1503                 .hook           = ip_vs_forward_icmp_v6,
1504                 .owner          = THIS_MODULE,
1505                 .pf             = PF_INET6,
1506                 .hooknum        = NF_INET_FORWARD,
1507                 .priority       = 99,
1508         },
1509 #endif
1510 };
1511
1512
1513 /*
1514  *      Initialize IP Virtual Server
1515  */
1516 static int __init ip_vs_init(void)
1517 {
1518         int ret;
1519
1520         ip_vs_estimator_init();
1521
1522         ret = ip_vs_control_init();
1523         if (ret < 0) {
1524                 pr_err("can't setup control.\n");
1525                 goto cleanup_estimator;
1526         }
1527
1528         ip_vs_protocol_init();
1529
1530         ret = ip_vs_app_init();
1531         if (ret < 0) {
1532                 pr_err("can't setup application helper.\n");
1533                 goto cleanup_protocol;
1534         }
1535
1536         ret = ip_vs_conn_init();
1537         if (ret < 0) {
1538                 pr_err("can't setup connection table.\n");
1539                 goto cleanup_app;
1540         }
1541
1542         ret = nf_register_hooks(ip_vs_ops, ARRAY_SIZE(ip_vs_ops));
1543         if (ret < 0) {
1544                 pr_err("can't register hooks.\n");
1545                 goto cleanup_conn;
1546         }
1547
1548         pr_info("ipvs loaded.\n");
1549         return ret;
1550
1551   cleanup_conn:
1552         ip_vs_conn_cleanup();
1553   cleanup_app:
1554         ip_vs_app_cleanup();
1555   cleanup_protocol:
1556         ip_vs_protocol_cleanup();
1557         ip_vs_control_cleanup();
1558   cleanup_estimator:
1559         ip_vs_estimator_cleanup();
1560         return ret;
1561 }
1562
1563 static void __exit ip_vs_cleanup(void)
1564 {
1565         nf_unregister_hooks(ip_vs_ops, ARRAY_SIZE(ip_vs_ops));
1566         ip_vs_conn_cleanup();
1567         ip_vs_app_cleanup();
1568         ip_vs_protocol_cleanup();
1569         ip_vs_control_cleanup();
1570         ip_vs_estimator_cleanup();
1571         pr_info("ipvs unloaded.\n");
1572 }
1573
1574 module_init(ip_vs_init);
1575 module_exit(ip_vs_cleanup);
1576 MODULE_LICENSE("GPL");