net/netfilter/ipvs/ip_vs_xmit.c

   1 /*
   2  * ip_vs_xmit.c: various packet transmitters for IPVS
   3  *
   4  * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
   5  *              Julian Anastasov <ja@ssi.bg>
   6  *
   7  *              This program is free software; you can redistribute it and/or
   8  *              modify it under the terms of the GNU General Public License
   9  *              as published by the Free Software Foundation; either version
  10  *              2 of the License, or (at your option) any later version.
  11  *
  12  * Changes:
  13  *
  14  * Description of forwarding methods:
  15  * - all transmitters are called from LOCAL_IN (remote clients) and
  16  * LOCAL_OUT (local clients) but for ICMP can be called from FORWARD
  17  * - not all connections have destination server, for example,
  18  * connections in backup server when fwmark is used
  19  * - bypass connections use daddr from packet
  20  * LOCAL_OUT rules:
  21  * - skb->dev is NULL, skb->protocol is not set (both are set in POST_ROUTING)
  22  * - skb->pkt_type is not set yet
  23  * - the only place where we can see skb->sk != NULL
  24  */
  25
  26 #define KMSG_COMPONENT "IPVS"
  27 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  28
  29 #include <linux/kernel.h>
  30 #include <linux/slab.h>
  31 #include <linux/tcp.h>                  /* for tcphdr */
  32 #include <net/ip.h>
  33 #include <net/tcp.h>                    /* for csum_tcpudp_magic */
  34 #include <net/udp.h>
  35 #include <net/icmp.h>                   /* for icmp_send */
  36 #include <net/route.h>                  /* for ip_route_output */
  37 #include <net/ipv6.h>
  38 #include <net/ip6_route.h>
  39 #include <net/addrconf.h>
  40 #include <linux/icmpv6.h>
  41 #include <linux/netfilter.h>
  42 #include <linux/netfilter_ipv4.h>
  43
  44 #include <net/ip_vs.h>
  45
  46
  47 /*
  48  *      Destination cache to speed up outgoing route lookup
  49  */
  50 static inline void
  51 __ip_vs_dst_set(struct ip_vs_dest *dest, u32 rtos, struct dst_entry *dst,
  52                 u32 dst_cookie)
  53 {
  54         struct dst_entry *old_dst;
  55
  56         old_dst = dest->dst_cache;
  57         dest->dst_cache = dst;
  58         dest->dst_rtos = rtos;
  59         dest->dst_cookie = dst_cookie;
  60         dst_release(old_dst);
  61 }
  62
  63 static inline struct dst_entry *
  64 __ip_vs_dst_check(struct ip_vs_dest *dest, u32 rtos)
  65 {
  66         struct dst_entry *dst = dest->dst_cache;
  67
  68         if (!dst)
  69                 return NULL;
  70         if ((dst->obsolete || rtos != dest->dst_rtos) &&
  71             dst->ops->check(dst, dest->dst_cookie) == NULL) {
  72                 dest->dst_cache = NULL;
  73                 dst_release(dst);
  74                 return NULL;
  75         }
  76         dst_hold(dst);
  77         return dst;
  78 }
  79
  80 /*
  81  * Get route to destination or remote server
  82  * rt_mode: flags, &1=Allow local dest, &2=Allow non-local dest,
  83  *          &4=Allow redirect from remote daddr to local
  84  */
  85 static struct rtable *
  86 __ip_vs_get_out_rt(struct sk_buff *skb, struct ip_vs_dest *dest,
  87                    __be32 daddr, u32 rtos, int rt_mode)
  88 {
  89         struct net *net = dev_net(skb_dst(skb)->dev);
  90         struct rtable *rt;                      /* Route to the other host */
  91         struct rtable *ort;                     /* Original route */
  92         int local;
  93
  94         if (dest) {
  95                 spin_lock(&dest->dst_lock);
  96                 if (!(rt = (struct rtable *)
  97                       __ip_vs_dst_check(dest, rtos))) {
  98                         struct flowi fl = {
  99                                 .oif = 0,
 100                                 .nl_u = {
 101                                         .ip4_u = {
 102                                                 .daddr = dest->addr.ip,
 103                                                 .saddr = 0,
 104                                                 .tos = rtos, } },
 105                         };
 106
 107                         if (ip_route_output_key(net, &rt, &fl)) {
 108                                 spin_unlock(&dest->dst_lock);
 109                                 IP_VS_DBG_RL("ip_route_output error, dest: %pI4\n",
 110                                              &dest->addr.ip);
 111                                 return NULL;
 112                         }
 113                         __ip_vs_dst_set(dest, rtos, dst_clone(&rt->dst), 0);
 114                         IP_VS_DBG(10, "new dst %pI4, refcnt=%d, rtos=%X\n",
 115                                   &dest->addr.ip,
 116                                   atomic_read(&rt->dst.__refcnt), rtos);
 117                 }
 118                 spin_unlock(&dest->dst_lock);
 119         } else {
 120                 struct flowi fl = {
 121                         .oif = 0,
 122                         .nl_u = {
 123                                 .ip4_u = {
 124                                         .daddr = daddr,
 125                                         .saddr = 0,
 126                                         .tos = rtos, } },
 127                 };
 128
 129                 if (ip_route_output_key(net, &rt, &fl)) {
 130                         IP_VS_DBG_RL("ip_route_output error, dest: %pI4\n",
 131                                      &daddr);
 132                         return NULL;
 133                 }
 134         }
 135
 136         local = rt->rt_flags & RTCF_LOCAL;
 137         if (!((local ? 1 : 2) & rt_mode)) {
 138                 IP_VS_DBG_RL("Stopping traffic to %s address, dest: %pI4\n",
 139                              (rt->rt_flags & RTCF_LOCAL) ?
 140                              "local":"non-local", &rt->rt_dst);
 141                 ip_rt_put(rt);
 142                 return NULL;
 143         }
 144         if (local && !(rt_mode & 4) && !((ort = skb_rtable(skb)) &&
 145                                          ort->rt_flags & RTCF_LOCAL)) {
 146                 IP_VS_DBG_RL("Redirect from non-local address %pI4 to local "
 147                              "requires NAT method, dest: %pI4\n",
 148                              &ip_hdr(skb)->daddr, &rt->rt_dst);
 149                 ip_rt_put(rt);
 150                 return NULL;
 151         }
 152         if (unlikely(!local && ipv4_is_loopback(ip_hdr(skb)->saddr))) {
 153                 IP_VS_DBG_RL("Stopping traffic from loopback address %pI4 "
 154                              "to non-local address, dest: %pI4\n",
 155                              &ip_hdr(skb)->saddr, &rt->rt_dst);
 156                 ip_rt_put(rt);
 157                 return NULL;
 158         }
 159
 160         return rt;
 161 }
 162
 163 /* Reroute packet to local IPv4 stack after DNAT */
 164 static int
 165 __ip_vs_reroute_locally(struct sk_buff *skb)
 166 {
 167         struct rtable *rt = skb_rtable(skb);
 168         struct net_device *dev = rt->dst.dev;
 169         struct net *net = dev_net(dev);
 170         struct iphdr *iph = ip_hdr(skb);
 171
 172         if (rt->fl.iif) {
 173                 unsigned long orefdst = skb->_skb_refdst;
 174
 175                 if (ip_route_input(skb, iph->daddr, iph->saddr,
 176                                    iph->tos, skb->dev))
 177                         return 0;
 178                 refdst_drop(orefdst);
 179         } else {
 180                 struct flowi fl = {
 181                         .oif = 0,
 182                         .nl_u = {
 183                                 .ip4_u = {
 184                                         .daddr = iph->daddr,
 185                                         .saddr = iph->saddr,
 186                                         .tos = RT_TOS(iph->tos),
 187                                 }
 188                         },
 189                         .mark = skb->mark,
 190                 };
 191                 struct rtable *rt;
 192
 193                 if (ip_route_output_key(net, &rt, &fl))
 194                         return 0;
 195                 if (!(rt->rt_flags & RTCF_LOCAL)) {
 196                         ip_rt_put(rt);
 197                         return 0;
 198                 }
 199                 /* Drop old route. */
 200                 skb_dst_drop(skb);
 201                 skb_dst_set(skb, &rt->dst);
 202         }
 203         return 1;
 204 }
 205
 206 #ifdef CONFIG_IP_VS_IPV6
 207
 208 static inline int __ip_vs_is_local_route6(struct rt6_info *rt)
 209 {
 210         return rt->rt6i_dev && rt->rt6i_dev->flags & IFF_LOOPBACK;
 211 }
 212
 213 static struct dst_entry *
 214 __ip_vs_route_output_v6(struct net *net, struct in6_addr *daddr,
 215                         struct in6_addr *ret_saddr, int do_xfrm)
 216 {
 217         struct dst_entry *dst;
 218         struct flowi fl = {
 219                 .oif = 0,
 220                 .nl_u = {
 221                         .ip6_u = {
 222                                 .daddr = *daddr,
 223                         },
 224                 },
 225         };
 226
 227         dst = ip6_route_output(net, NULL, &fl);
 228         if (dst->error)
 229                 goto out_err;
 230         if (!ret_saddr)
 231                 return dst;
 232         if (ipv6_addr_any(&fl.fl6_src) &&
 233             ipv6_dev_get_saddr(net, ip6_dst_idev(dst)->dev,
 234                                &fl.fl6_dst, 0, &fl.fl6_src) < 0)
 235                 goto out_err;
 236         if (do_xfrm && xfrm_lookup(net, &dst, &fl, NULL, 0) < 0)
 237                 goto out_err;
 238         ipv6_addr_copy(ret_saddr, &fl.fl6_src);
 239         return dst;
 240
 241 out_err:
 242         dst_release(dst);
 243         IP_VS_DBG_RL("ip6_route_output error, dest: %pI6\n", daddr);
 244         return NULL;
 245 }
 246
 247 /*
 248  * Get route to destination or remote server
 249  * rt_mode: flags, &1=Allow local dest, &2=Allow non-local dest,
 250  *          &4=Allow redirect from remote daddr to local
 251  */
 252 static struct rt6_info *
 253 __ip_vs_get_out_rt_v6(struct sk_buff *skb, struct ip_vs_dest *dest,
 254                       struct in6_addr *daddr, struct in6_addr *ret_saddr,
 255                       int do_xfrm, int rt_mode)
 256 {
 257         struct net *net = dev_net(skb_dst(skb)->dev);
 258         struct rt6_info *rt;                    /* Route to the other host */
 259         struct rt6_info *ort;                   /* Original route */
 260         struct dst_entry *dst;
 261         int local;
 262
 263         if (dest) {
 264                 spin_lock(&dest->dst_lock);
 265                 rt = (struct rt6_info *)__ip_vs_dst_check(dest, 0);
 266                 if (!rt) {
 267                         u32 cookie;
 268
 269                         dst = __ip_vs_route_output_v6(net, &dest->addr.in6,
 270                                                       &dest->dst_saddr,
 271                                                       do_xfrm);
 272                         if (!dst) {
 273                                 spin_unlock(&dest->dst_lock);
 274                                 return NULL;
 275                         }
 276                         rt = (struct rt6_info *) dst;
 277                         cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
 278                         __ip_vs_dst_set(dest, 0, dst_clone(&rt->dst), cookie);
 279                         IP_VS_DBG(10, "new dst %pI6, src %pI6, refcnt=%d\n",
 280                                   &dest->addr.in6, &dest->dst_saddr,
 281                                   atomic_read(&rt->dst.__refcnt));
 282                 }
 283                 if (ret_saddr)
 284                         ipv6_addr_copy(ret_saddr, &dest->dst_saddr);
 285                 spin_unlock(&dest->dst_lock);
 286         } else {
 287                 dst = __ip_vs_route_output_v6(net, daddr, ret_saddr, do_xfrm);
 288                 if (!dst)
 289                         return NULL;
 290                 rt = (struct rt6_info *) dst;
 291         }
 292
 293         local = __ip_vs_is_local_route6(rt);
 294         if (!((local ? 1 : 2) & rt_mode)) {
 295                 IP_VS_DBG_RL("Stopping traffic to %s address, dest: %pI6\n",
 296                              local ? "local":"non-local", daddr);
 297                 dst_release(&rt->dst);
 298                 return NULL;
 299         }
 300         if (local && !(rt_mode & 4) &&
 301             !((ort = (struct rt6_info *) skb_dst(skb)) &&
 302               __ip_vs_is_local_route6(ort))) {
 303                 IP_VS_DBG_RL("Redirect from non-local address %pI6 to local "
 304                              "requires NAT method, dest: %pI6\n",
 305                              &ipv6_hdr(skb)->daddr, daddr);
 306                 dst_release(&rt->dst);
 307                 return NULL;
 308         }
 309         if (unlikely(!local && (!skb->dev || skb->dev->flags & IFF_LOOPBACK) &&
 310                      ipv6_addr_type(&ipv6_hdr(skb)->saddr) &
 311                                     IPV6_ADDR_LOOPBACK)) {
 312                 IP_VS_DBG_RL("Stopping traffic from loopback address %pI6 "
 313                              "to non-local address, dest: %pI6\n",
 314                              &ipv6_hdr(skb)->saddr, daddr);
 315                 dst_release(&rt->dst);
 316                 return NULL;
 317         }
 318
 319         return rt;
 320 }
 321 #endif
 322
 323
 324 /*
 325  *      Release dest->dst_cache before a dest is removed
 326  */
 327 void
 328 ip_vs_dst_reset(struct ip_vs_dest *dest)
 329 {
 330         struct dst_entry *old_dst;
 331
 332         old_dst = dest->dst_cache;
 333         dest->dst_cache = NULL;
 334         dst_release(old_dst);
 335 }
 336
 337 #define IP_VS_XMIT_TUNNEL(skb, cp)                              \
 338 ({                                                              \
 339         int __ret = NF_ACCEPT;                                  \
 340                                                                 \
 341         (skb)->ipvs_property = 1;                               \
 342         if (unlikely((cp)->flags & IP_VS_CONN_F_NFCT))          \
 343                 __ret = ip_vs_confirm_conntrack(skb, cp);       \
 344         if (__ret == NF_ACCEPT) {                               \
 345                 nf_reset(skb);                                  \
 346                 skb_forward_csum(skb);                          \
 347         }                                                       \
 348         __ret;                                                  \
 349 })
 350
 351 #define IP_VS_XMIT_NAT(pf, skb, cp, local)              \
 352 do {                                                    \
 353         (skb)->ipvs_property = 1;                       \
 354         if (likely(!((cp)->flags & IP_VS_CONN_F_NFCT))) \
 355                 ip_vs_notrack(skb);                     \
 356         else                                            \
 357                 ip_vs_update_conntrack(skb, cp, 1);     \
 358         if (local)                                      \
 359                 return NF_ACCEPT;                       \
 360         skb_forward_csum(skb);                          \
 361         NF_HOOK(pf, NF_INET_LOCAL_OUT, (skb), NULL,     \
 362                 skb_dst(skb)->dev, dst_output);         \
 363 } while (0)
 364
 365 #define IP_VS_XMIT(pf, skb, cp, local)                  \
 366 do {                                                    \
 367         (skb)->ipvs_property = 1;                       \
 368         if (likely(!((cp)->flags & IP_VS_CONN_F_NFCT))) \
 369                 ip_vs_notrack(skb);                     \
 370         if (local)                                      \
 371                 return NF_ACCEPT;                       \
 372         skb_forward_csum(skb);                          \
 373         NF_HOOK(pf, NF_INET_LOCAL_OUT, (skb), NULL,     \
 374                 skb_dst(skb)->dev, dst_output);         \
 375 } while (0)
 376
 377
 378 /*
 379  *      NULL transmitter (do nothing except return NF_ACCEPT)
 380  */
 381 int
 382 ip_vs_null_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 383                 struct ip_vs_protocol *pp)
 384 {
 385         /* we do not touch skb and do not need pskb ptr */
 386         IP_VS_XMIT(NFPROTO_IPV4, skb, cp, 1);
 387 }
 388
 389
 390 /*
 391  *      Bypass transmitter
 392  *      Let packets bypass the destination when the destination is not
 393  *      available, it may be only used in transparent cache cluster.
 394  */
 395 int
 396 ip_vs_bypass_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 397                   struct ip_vs_protocol *pp)
 398 {
 399         struct rtable *rt;                      /* Route to the other host */
 400         struct iphdr  *iph = ip_hdr(skb);
 401         int    mtu;
 402
 403         EnterFunction(10);
 404
 405         if (!(rt = __ip_vs_get_out_rt(skb, NULL, iph->daddr,
 406                                       RT_TOS(iph->tos), 2)))
 407                 goto tx_error_icmp;
 408
 409         /* MTU checking */
 410         mtu = dst_mtu(&rt->dst);
 411         if ((skb->len > mtu) && (iph->frag_off & htons(IP_DF))) {
 412                 ip_rt_put(rt);
 413                 icmp_send(skb, ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED, htonl(mtu));
 414                 IP_VS_DBG_RL("%s(): frag needed\n", __func__);
 415                 goto tx_error;
 416         }
 417
 418         /*
 419          * Call ip_send_check because we are not sure it is called
 420          * after ip_defrag. Is copy-on-write needed?
 421          */
 422         if (unlikely((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)) {
 423                 ip_rt_put(rt);
 424                 return NF_STOLEN;
 425         }
 426         ip_send_check(ip_hdr(skb));
 427
 428         /* drop old route */
 429         skb_dst_drop(skb);
 430         skb_dst_set(skb, &rt->dst);
 431
 432         /* Another hack: avoid icmp_send in ip_fragment */
 433         skb->local_df = 1;
 434
 435         IP_VS_XMIT(NFPROTO_IPV4, skb, cp, 0);
 436
 437         LeaveFunction(10);
 438         return NF_STOLEN;
 439
 440  tx_error_icmp:
 441         dst_link_failure(skb);
 442  tx_error:
 443         kfree_skb(skb);
 444         LeaveFunction(10);
 445         return NF_STOLEN;
 446 }
 447
 448 #ifdef CONFIG_IP_VS_IPV6
 449 int
 450 ip_vs_bypass_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
 451                      struct ip_vs_protocol *pp)
 452 {
 453         struct rt6_info *rt;                    /* Route to the other host */
 454         struct ipv6hdr  *iph = ipv6_hdr(skb);
 455         int    mtu;
 456
 457         EnterFunction(10);
 458
 459         if (!(rt = __ip_vs_get_out_rt_v6(skb, NULL, &iph->daddr, NULL, 0, 2)))
 460                 goto tx_error_icmp;
 461
 462         /* MTU checking */
 463         mtu = dst_mtu(&rt->dst);
 464         if (skb->len > mtu) {
 465                 if (!skb->dev) {
 466                         struct net *net = dev_net(skb_dst(skb)->dev);
 467
 468                         skb->dev = net->loopback_dev;
 469                 }
 470                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 471                 dst_release(&rt->dst);
 472                 IP_VS_DBG_RL("%s(): frag needed\n", __func__);
 473                 goto tx_error;
 474         }
 475
 476         /*
 477          * Call ip_send_check because we are not sure it is called
 478          * after ip_defrag. Is copy-on-write needed?
 479          */
 480         skb = skb_share_check(skb, GFP_ATOMIC);
 481         if (unlikely(skb == NULL)) {
 482                 dst_release(&rt->dst);
 483                 return NF_STOLEN;
 484         }
 485
 486         /* drop old route */
 487         skb_dst_drop(skb);
 488         skb_dst_set(skb, &rt->dst);
 489
 490         /* Another hack: avoid icmp_send in ip_fragment */
 491         skb->local_df = 1;
 492
 493         IP_VS_XMIT(NFPROTO_IPV6, skb, cp, 0);
 494
 495         LeaveFunction(10);
 496         return NF_STOLEN;
 497
 498  tx_error_icmp:
 499         dst_link_failure(skb);
 500  tx_error:
 501         kfree_skb(skb);
 502         LeaveFunction(10);
 503         return NF_STOLEN;
 504 }
 505 #endif
 506
 507 /*
 508  *      NAT transmitter (only for outside-to-inside nat forwarding)
 509  *      Not used for related ICMP
 510  */
 511 int
 512 ip_vs_nat_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 513                struct ip_vs_protocol *pp)
 514 {
 515         struct rtable *rt;              /* Route to the other host */
 516         int mtu;
 517         struct iphdr *iph = ip_hdr(skb);
 518         int local;
 519
 520         EnterFunction(10);
 521
 522         /* check if it is a connection of no-client-port */
 523         if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT)) {
 524                 __be16 _pt, *p;
 525                 p = skb_header_pointer(skb, iph->ihl*4, sizeof(_pt), &_pt);
 526                 if (p == NULL)
 527                         goto tx_error;
 528                 ip_vs_conn_fill_cport(cp, *p);
 529                 IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
 530         }
 531
 532         if (!(rt = __ip_vs_get_out_rt(skb, cp->dest, cp->daddr.ip,
 533                                       RT_TOS(iph->tos), 1|2|4)))
 534                 goto tx_error_icmp;
 535         local = rt->rt_flags & RTCF_LOCAL;
 536         /*
 537          * Avoid duplicate tuple in reply direction for NAT traffic
 538          * to local address when connection is sync-ed
 539          */
 540 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 541         if (cp->flags & IP_VS_CONN_F_SYNC && local) {
 542                 enum ip_conntrack_info ctinfo;
 543                 struct nf_conn *ct = ct = nf_ct_get(skb, &ctinfo);
 544
 545                 if (ct && !nf_ct_is_untracked(ct)) {
 546                         IP_VS_DBG_RL_PKT(10, AF_INET, pp, skb, 0,
 547                                          "ip_vs_nat_xmit(): "
 548                                          "stopping DNAT to local address");
 549                         goto tx_error_put;
 550                 }
 551         }
 552 #endif
 553
 554         /* From world but DNAT to loopback address? */
 555         if (local && ipv4_is_loopback(rt->rt_dst) && skb_rtable(skb)->fl.iif) {
 556                 IP_VS_DBG_RL_PKT(1, AF_INET, pp, skb, 0, "ip_vs_nat_xmit(): "
 557                                  "stopping DNAT to loopback address");
 558                 goto tx_error_put;
 559         }
 560
 561         /* MTU checking */
 562         mtu = dst_mtu(&rt->dst);
 563         if ((skb->len > mtu) && (iph->frag_off & htons(IP_DF))) {
 564                 icmp_send(skb, ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED, htonl(mtu));
 565                 IP_VS_DBG_RL_PKT(0, AF_INET, pp, skb, 0,
 566                                  "ip_vs_nat_xmit(): frag needed for");
 567                 goto tx_error_put;
 568         }
 569
 570         /* copy-on-write the packet before mangling it */
 571         if (!skb_make_writable(skb, sizeof(struct iphdr)))
 572                 goto tx_error_put;
 573
 574         if (skb_cow(skb, rt->dst.dev->hard_header_len))
 575                 goto tx_error_put;
 576
 577         /* mangle the packet */
 578         if (pp->dnat_handler && !pp->dnat_handler(skb, pp, cp))
 579                 goto tx_error_put;
 580         ip_hdr(skb)->daddr = cp->daddr.ip;
 581         ip_send_check(ip_hdr(skb));
 582
 583         if (!local) {
 584                 /* drop old route */
 585                 skb_dst_drop(skb);
 586                 skb_dst_set(skb, &rt->dst);
 587         } else {
 588                 ip_rt_put(rt);
 589                 /*
 590                  * Some IPv4 replies get local address from routes,
 591                  * not from iph, so while we DNAT after routing
 592                  * we need this second input/output route.
 593                  */
 594                 if (!__ip_vs_reroute_locally(skb))
 595                         goto tx_error;
 596         }
 597
 598         IP_VS_DBG_PKT(10, AF_INET, pp, skb, 0, "After DNAT");
 599
 600         /* FIXME: when application helper enlarges the packet and the length
 601            is larger than the MTU of outgoing device, there will be still
 602            MTU problem. */
 603
 604         /* Another hack: avoid icmp_send in ip_fragment */
 605         skb->local_df = 1;
 606
 607         IP_VS_XMIT_NAT(NFPROTO_IPV4, skb, cp, local);
 608
 609         LeaveFunction(10);
 610         return NF_STOLEN;
 611
 612   tx_error_icmp:
 613         dst_link_failure(skb);
 614   tx_error:
 615         kfree_skb(skb);
 616         LeaveFunction(10);
 617         return NF_STOLEN;
 618   tx_error_put:
 619         ip_rt_put(rt);
 620         goto tx_error;
 621 }
 622
 623 #ifdef CONFIG_IP_VS_IPV6
 624 int
 625 ip_vs_nat_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
 626                   struct ip_vs_protocol *pp)
 627 {
 628         struct rt6_info *rt;            /* Route to the other host */
 629         int mtu;
 630         int local;
 631
 632         EnterFunction(10);
 633
 634         /* check if it is a connection of no-client-port */
 635         if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT)) {
 636                 __be16 _pt, *p;
 637                 p = skb_header_pointer(skb, sizeof(struct ipv6hdr),
 638                                        sizeof(_pt), &_pt);
 639                 if (p == NULL)
 640                         goto tx_error;
 641                 ip_vs_conn_fill_cport(cp, *p);
 642                 IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
 643         }
 644
 645         if (!(rt = __ip_vs_get_out_rt_v6(skb, cp->dest, &cp->daddr.in6, NULL,
 646                                          0, 1|2|4)))
 647                 goto tx_error_icmp;
 648         local = __ip_vs_is_local_route6(rt);
 649         /*
 650          * Avoid duplicate tuple in reply direction for NAT traffic
 651          * to local address when connection is sync-ed
 652          */
 653 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 654         if (cp->flags & IP_VS_CONN_F_SYNC && local) {
 655                 enum ip_conntrack_info ctinfo;
 656                 struct nf_conn *ct = ct = nf_ct_get(skb, &ctinfo);
 657
 658                 if (ct && !nf_ct_is_untracked(ct)) {
 659                         IP_VS_DBG_RL_PKT(10, AF_INET6, pp, skb, 0,
 660                                          "ip_vs_nat_xmit_v6(): "
 661                                          "stopping DNAT to local address");
 662                         goto tx_error_put;
 663                 }
 664         }
 665 #endif
 666
 667         /* From world but DNAT to loopback address? */
 668         if (local && skb->dev && !(skb->dev->flags & IFF_LOOPBACK) &&
 669             ipv6_addr_type(&rt->rt6i_dst.addr) & IPV6_ADDR_LOOPBACK) {
 670                 IP_VS_DBG_RL_PKT(1, AF_INET6, pp, skb, 0,
 671                                  "ip_vs_nat_xmit_v6(): "
 672                                  "stopping DNAT to loopback address");
 673                 goto tx_error_put;
 674         }
 675
 676         /* MTU checking */
 677         mtu = dst_mtu(&rt->dst);
 678         if (skb->len > mtu) {
 679                 if (!skb->dev) {
 680                         struct net *net = dev_net(skb_dst(skb)->dev);
 681
 682                         skb->dev = net->loopback_dev;
 683                 }
 684                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 685                 IP_VS_DBG_RL_PKT(0, AF_INET6, pp, skb, 0,
 686                                  "ip_vs_nat_xmit_v6(): frag needed for");
 687                 goto tx_error_put;
 688         }
 689
 690         /* copy-on-write the packet before mangling it */
 691         if (!skb_make_writable(skb, sizeof(struct ipv6hdr)))
 692                 goto tx_error_put;
 693
 694         if (skb_cow(skb, rt->dst.dev->hard_header_len))
 695                 goto tx_error_put;
 696
 697         /* mangle the packet */
 698         if (pp->dnat_handler && !pp->dnat_handler(skb, pp, cp))
 699                 goto tx_error;
 700         ipv6_addr_copy(&ipv6_hdr(skb)->daddr, &cp->daddr.in6);
 701
 702         if (!local || !skb->dev) {
 703                 /* drop the old route when skb is not shared */
 704                 skb_dst_drop(skb);
 705                 skb_dst_set(skb, &rt->dst);
 706         } else {
 707                 /* destined to loopback, do we need to change route? */
 708                 dst_release(&rt->dst);
 709         }
 710
 711         IP_VS_DBG_PKT(10, AF_INET6, pp, skb, 0, "After DNAT");
 712
 713         /* FIXME: when application helper enlarges the packet and the length
 714            is larger than the MTU of outgoing device, there will be still
 715            MTU problem. */
 716
 717         /* Another hack: avoid icmp_send in ip_fragment */
 718         skb->local_df = 1;
 719
 720         IP_VS_XMIT_NAT(NFPROTO_IPV6, skb, cp, local);
 721
 722         LeaveFunction(10);
 723         return NF_STOLEN;
 724
 725 tx_error_icmp:
 726         dst_link_failure(skb);
 727 tx_error:
 728         LeaveFunction(10);
 729         kfree_skb(skb);
 730         return NF_STOLEN;
 731 tx_error_put:
 732         dst_release(&rt->dst);
 733         goto tx_error;
 734 }
 735 #endif
 736
 737
 738 /*
 739  *   IP Tunneling transmitter
 740  *
 741  *   This function encapsulates the packet in a new IP packet, its
 742  *   destination will be set to cp->daddr. Most code of this function
 743  *   is taken from ipip.c.
 744  *
 745  *   It is used in VS/TUN cluster. The load balancer selects a real
 746  *   server from a cluster based on a scheduling algorithm,
 747  *   encapsulates the request packet and forwards it to the selected
 748  *   server. For example, all real servers are configured with
 749  *   "ifconfig tunl0 <Virtual IP Address> up". When the server receives
 750  *   the encapsulated packet, it will decapsulate the packet, processe
 751  *   the request and return the response packets directly to the client
 752  *   without passing the load balancer. This can greatly increase the
 753  *   scalability of virtual server.
 754  *
 755  *   Used for ANY protocol
 756  */
 757 int
 758 ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 759                   struct ip_vs_protocol *pp)
 760 {
 761         struct rtable *rt;                      /* Route to the other host */
 762         struct net_device *tdev;                /* Device to other host */
 763         struct iphdr  *old_iph = ip_hdr(skb);
 764         u8     tos = old_iph->tos;
 765         __be16 df = old_iph->frag_off;
 766         struct iphdr  *iph;                     /* Our new IP header */
 767         unsigned int max_headroom;              /* The extra header space needed */
 768         int    mtu;
 769         int ret;
 770
 771         EnterFunction(10);
 772
 773         if (!(rt = __ip_vs_get_out_rt(skb, cp->dest, cp->daddr.ip,
 774                                       RT_TOS(tos), 1|2)))
 775                 goto tx_error_icmp;
 776         if (rt->rt_flags & RTCF_LOCAL) {
 777                 ip_rt_put(rt);
 778                 IP_VS_XMIT(NFPROTO_IPV4, skb, cp, 1);
 779         }
 780
 781         tdev = rt->dst.dev;
 782
 783         mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
 784         if (mtu < 68) {
 785                 IP_VS_DBG_RL("%s(): mtu less than 68\n", __func__);
 786                 goto tx_error_put;
 787         }
 788         if (skb_dst(skb))
 789                 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
 790
 791         df |= (old_iph->frag_off & htons(IP_DF));
 792
 793         if ((old_iph->frag_off & htons(IP_DF))
 794             && mtu < ntohs(old_iph->tot_len)) {
 795                 icmp_send(skb, ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED, htonl(mtu));
 796                 IP_VS_DBG_RL("%s(): frag needed\n", __func__);
 797                 goto tx_error_put;
 798         }
 799
 800         /*
 801          * Okay, now see if we can stuff it in the buffer as-is.
 802          */
 803         max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct iphdr);
 804
 805         if (skb_headroom(skb) < max_headroom
 806             || skb_cloned(skb) || skb_shared(skb)) {
 807                 struct sk_buff *new_skb =
 808                         skb_realloc_headroom(skb, max_headroom);
 809                 if (!new_skb) {
 810                         ip_rt_put(rt);
 811                         kfree_skb(skb);
 812                         IP_VS_ERR_RL("%s(): no memory\n", __func__);
 813                         return NF_STOLEN;
 814                 }
 815                 kfree_skb(skb);
 816                 skb = new_skb;
 817                 old_iph = ip_hdr(skb);
 818         }
 819
 820         skb->transport_header = skb->network_header;
 821
 822         /* fix old IP header checksum */
 823         ip_send_check(old_iph);
 824
 825         skb_push(skb, sizeof(struct iphdr));
 826         skb_reset_network_header(skb);
 827         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 828
 829         /* drop old route */
 830         skb_dst_drop(skb);
 831         skb_dst_set(skb, &rt->dst);
 832
 833         /*
 834          *      Push down and install the IPIP header.
 835          */
 836         iph                     =       ip_hdr(skb);
 837         iph->version            =       4;
 838         iph->ihl                =       sizeof(struct iphdr)>>2;
 839         iph->frag_off           =       df;
 840         iph->protocol           =       IPPROTO_IPIP;
 841         iph->tos                =       tos;
 842         iph->daddr              =       rt->rt_dst;
 843         iph->saddr              =       rt->rt_src;
 844         iph->ttl                =       old_iph->ttl;
 845         ip_select_ident(iph, &rt->dst, NULL);
 846
 847         /* Another hack: avoid icmp_send in ip_fragment */
 848         skb->local_df = 1;
 849
 850         ret = IP_VS_XMIT_TUNNEL(skb, cp);
 851         if (ret == NF_ACCEPT)
 852                 ip_local_out(skb);
 853         else if (ret == NF_DROP)
 854                 kfree_skb(skb);
 855
 856         LeaveFunction(10);
 857
 858         return NF_STOLEN;
 859
 860   tx_error_icmp:
 861         dst_link_failure(skb);
 862   tx_error:
 863         kfree_skb(skb);
 864         LeaveFunction(10);
 865         return NF_STOLEN;
 866 tx_error_put:
 867         ip_rt_put(rt);
 868         goto tx_error;
 869 }
 870
 871 #ifdef CONFIG_IP_VS_IPV6
 872 int
 873 ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
 874                      struct ip_vs_protocol *pp)
 875 {
 876         struct rt6_info *rt;            /* Route to the other host */
 877         struct in6_addr saddr;          /* Source for tunnel */
 878         struct net_device *tdev;        /* Device to other host */
 879         struct ipv6hdr  *old_iph = ipv6_hdr(skb);
 880         struct ipv6hdr  *iph;           /* Our new IP header */
 881         unsigned int max_headroom;      /* The extra header space needed */
 882         int    mtu;
 883         int ret;
 884
 885         EnterFunction(10);
 886
 887         if (!(rt = __ip_vs_get_out_rt_v6(skb, cp->dest, &cp->daddr.in6,
 888                                          &saddr, 1, 1|2)))
 889                 goto tx_error_icmp;
 890         if (__ip_vs_is_local_route6(rt)) {
 891                 dst_release(&rt->dst);
 892                 IP_VS_XMIT(NFPROTO_IPV6, skb, cp, 1);
 893         }
 894
 895         tdev = rt->dst.dev;
 896
 897         mtu = dst_mtu(&rt->dst) - sizeof(struct ipv6hdr);
 898         if (mtu < IPV6_MIN_MTU) {
 899                 IP_VS_DBG_RL("%s(): mtu less than %d\n", __func__,
 900                              IPV6_MIN_MTU);
 901                 goto tx_error_put;
 902         }
 903         if (skb_dst(skb))
 904                 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
 905
 906         if (mtu < ntohs(old_iph->payload_len) + sizeof(struct ipv6hdr)) {
 907                 if (!skb->dev) {
 908                         struct net *net = dev_net(skb_dst(skb)->dev);
 909
 910                         skb->dev = net->loopback_dev;
 911                 }
 912                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 913                 IP_VS_DBG_RL("%s(): frag needed\n", __func__);
 914                 goto tx_error_put;
 915         }
 916
 917         /*
 918          * Okay, now see if we can stuff it in the buffer as-is.
 919          */
 920         max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct ipv6hdr);
 921
 922         if (skb_headroom(skb) < max_headroom
 923             || skb_cloned(skb) || skb_shared(skb)) {
 924                 struct sk_buff *new_skb =
 925                         skb_realloc_headroom(skb, max_headroom);
 926                 if (!new_skb) {
 927                         dst_release(&rt->dst);
 928                         kfree_skb(skb);
 929                         IP_VS_ERR_RL("%s(): no memory\n", __func__);
 930                         return NF_STOLEN;
 931                 }
 932                 kfree_skb(skb);
 933                 skb = new_skb;
 934                 old_iph = ipv6_hdr(skb);
 935         }
 936
 937         skb->transport_header = skb->network_header;
 938
 939         skb_push(skb, sizeof(struct ipv6hdr));
 940         skb_reset_network_header(skb);
 941         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 942
 943         /* drop old route */
 944         skb_dst_drop(skb);
 945         skb_dst_set(skb, &rt->dst);
 946
 947         /*
 948          *      Push down and install the IPIP header.
 949          */
 950         iph                     =       ipv6_hdr(skb);
 951         iph->version            =       6;
 952         iph->nexthdr            =       IPPROTO_IPV6;
 953         iph->payload_len        =       old_iph->payload_len;
 954         be16_add_cpu(&iph->payload_len, sizeof(*old_iph));
 955         iph->priority           =       old_iph->priority;
 956         memset(&iph->flow_lbl, 0, sizeof(iph->flow_lbl));
 957         ipv6_addr_copy(&iph->daddr, &cp->daddr.in6);
 958         ipv6_addr_copy(&iph->saddr, &saddr);
 959         iph->hop_limit          =       old_iph->hop_limit;
 960
 961         /* Another hack: avoid icmp_send in ip_fragment */
 962         skb->local_df = 1;
 963
 964         ret = IP_VS_XMIT_TUNNEL(skb, cp);
 965         if (ret == NF_ACCEPT)
 966                 ip6_local_out(skb);
 967         else if (ret == NF_DROP)
 968                 kfree_skb(skb);
 969
 970         LeaveFunction(10);
 971
 972         return NF_STOLEN;
 973
 974 tx_error_icmp:
 975         dst_link_failure(skb);
 976 tx_error:
 977         kfree_skb(skb);
 978         LeaveFunction(10);
 979         return NF_STOLEN;
 980 tx_error_put:
 981         dst_release(&rt->dst);
 982         goto tx_error;
 983 }
 984 #endif
 985
 986
 987 /*
 988  *      Direct Routing transmitter
 989  *      Used for ANY protocol
 990  */
 991 int
 992 ip_vs_dr_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 993               struct ip_vs_protocol *pp)
 994 {
 995         struct rtable *rt;                      /* Route to the other host */
 996         struct iphdr  *iph = ip_hdr(skb);
 997         int    mtu;
 998
 999         EnterFunction(10);
1000
1001         if (!(rt = __ip_vs_get_out_rt(skb, cp->dest, cp->daddr.ip,
1002                                       RT_TOS(iph->tos), 1|2)))
1003                 goto tx_error_icmp;
1004         if (rt->rt_flags & RTCF_LOCAL) {
1005                 ip_rt_put(rt);
1006                 IP_VS_XMIT(NFPROTO_IPV4, skb, cp, 1);
1007         }
1008
1009         /* MTU checking */
1010         mtu = dst_mtu(&rt->dst);
1011         if ((iph->frag_off & htons(IP_DF)) && skb->len > mtu) {
1012                 icmp_send(skb, ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED, htonl(mtu));
1013                 ip_rt_put(rt);
1014                 IP_VS_DBG_RL("%s(): frag needed\n", __func__);
1015                 goto tx_error;
1016         }
1017
1018         /*
1019          * Call ip_send_check because we are not sure it is called
1020          * after ip_defrag. Is copy-on-write needed?
1021          */
1022         if (unlikely((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)) {
1023                 ip_rt_put(rt);
1024                 return NF_STOLEN;
1025         }
1026         ip_send_check(ip_hdr(skb));
1027
1028         /* drop old route */
1029         skb_dst_drop(skb);
1030         skb_dst_set(skb, &rt->dst);
1031
1032         /* Another hack: avoid icmp_send in ip_fragment */
1033         skb->local_df = 1;
1034
1035         IP_VS_XMIT(NFPROTO_IPV4, skb, cp, 0);
1036
1037         LeaveFunction(10);
1038         return NF_STOLEN;
1039
1040   tx_error_icmp:
1041         dst_link_failure(skb);
1042   tx_error:
1043         kfree_skb(skb);
1044         LeaveFunction(10);
1045         return NF_STOLEN;
1046 }
1047
1048 #ifdef CONFIG_IP_VS_IPV6
1049 int
1050 ip_vs_dr_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
1051                  struct ip_vs_protocol *pp)
1052 {
1053         struct rt6_info *rt;                    /* Route to the other host */
1054         int    mtu;
1055
1056         EnterFunction(10);
1057
1058         if (!(rt = __ip_vs_get_out_rt_v6(skb, cp->dest, &cp->daddr.in6, NULL,
1059                                          0, 1|2)))
1060                 goto tx_error_icmp;
1061         if (__ip_vs_is_local_route6(rt)) {
1062                 dst_release(&rt->dst);
1063                 IP_VS_XMIT(NFPROTO_IPV6, skb, cp, 1);
1064         }
1065
1066         /* MTU checking */
1067         mtu = dst_mtu(&rt->dst);
1068         if (skb->len > mtu) {
1069                 if (!skb->dev) {
1070                         struct net *net = dev_net(skb_dst(skb)->dev);
1071
1072                         skb->dev = net->loopback_dev;
1073                 }
1074                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
1075                 dst_release(&rt->dst);
1076                 IP_VS_DBG_RL("%s(): frag needed\n", __func__);
1077                 goto tx_error;
1078         }
1079
1080         /*
1081          * Call ip_send_check because we are not sure it is called
1082          * after ip_defrag. Is copy-on-write needed?
1083          */
1084         skb = skb_share_check(skb, GFP_ATOMIC);
1085         if (unlikely(skb == NULL)) {
1086                 dst_release(&rt->dst);
1087                 return NF_STOLEN;
1088         }
1089
1090         /* drop old route */
1091         skb_dst_drop(skb);
1092         skb_dst_set(skb, &rt->dst);
1093
1094         /* Another hack: avoid icmp_send in ip_fragment */
1095         skb->local_df = 1;
1096
1097         IP_VS_XMIT(NFPROTO_IPV6, skb, cp, 0);
1098
1099         LeaveFunction(10);
1100         return NF_STOLEN;
1101
1102 tx_error_icmp:
1103         dst_link_failure(skb);
1104 tx_error:
1105         kfree_skb(skb);
1106         LeaveFunction(10);
1107         return NF_STOLEN;
1108 }
1109 #endif
1110
1111
1112 /*
1113  *      ICMP packet transmitter
1114  *      called by the ip_vs_in_icmp
1115  */
1116 int
1117 ip_vs_icmp_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
1118                 struct ip_vs_protocol *pp, int offset)
1119 {
1120         struct rtable   *rt;    /* Route to the other host */
1121         int mtu;
1122         int rc;
1123         int local;
1124
1125         EnterFunction(10);
1126
1127         /* The ICMP packet for VS/TUN, VS/DR and LOCALNODE will be
1128            forwarded directly here, because there is no need to
1129            translate address/port back */
1130         if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ) {
1131                 if (cp->packet_xmit)
1132                         rc = cp->packet_xmit(skb, cp, pp);
1133                 else
1134                         rc = NF_ACCEPT;
1135                 /* do not touch skb anymore */
1136                 atomic_inc(&cp->in_pkts);
1137                 goto out;
1138         }
1139
1140         /*
1141          * mangle and send the packet here (only for VS/NAT)
1142          */
1143
1144         if (!(rt = __ip_vs_get_out_rt(skb, cp->dest, cp->daddr.ip,
1145                                       RT_TOS(ip_hdr(skb)->tos), 1|2|4)))
1146                 goto tx_error_icmp;
1147         local = rt->rt_flags & RTCF_LOCAL;
1148
1149         /*
1150          * Avoid duplicate tuple in reply direction for NAT traffic
1151          * to local address when connection is sync-ed
1152          */
1153 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1154         if (cp->flags & IP_VS_CONN_F_SYNC && local) {
1155                 enum ip_conntrack_info ctinfo;
1156                 struct nf_conn *ct = ct = nf_ct_get(skb, &ctinfo);
1157
1158                 if (ct && !nf_ct_is_untracked(ct)) {
1159                         IP_VS_DBG(10, "%s(): "
1160                                   "stopping DNAT to local address %pI4\n",
1161                                   __func__, &cp->daddr.ip);
1162                         goto tx_error_put;
1163                 }
1164         }
1165 #endif
1166
1167         /* From world but DNAT to loopback address? */
1168         if (local && ipv4_is_loopback(rt->rt_dst) && skb_rtable(skb)->fl.iif) {
1169                 IP_VS_DBG(1, "%s(): "
1170                           "stopping DNAT to loopback %pI4\n",
1171                           __func__, &cp->daddr.ip);
1172                 goto tx_error_put;
1173         }
1174
1175         /* MTU checking */
1176         mtu = dst_mtu(&rt->dst);
1177         if ((skb->len > mtu) && (ip_hdr(skb)->frag_off & htons(IP_DF))) {
1178                 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
1179                 IP_VS_DBG_RL("%s(): frag needed\n", __func__);
1180                 goto tx_error_put;
1181         }
1182
1183         /* copy-on-write the packet before mangling it */
1184         if (!skb_make_writable(skb, offset))
1185                 goto tx_error_put;
1186
1187         if (skb_cow(skb, rt->dst.dev->hard_header_len))
1188                 goto tx_error_put;
1189
1190         ip_vs_nat_icmp(skb, pp, cp, 0);
1191
1192         if (!local) {
1193                 /* drop the old route when skb is not shared */
1194                 skb_dst_drop(skb);
1195                 skb_dst_set(skb, &rt->dst);
1196         } else {
1197                 ip_rt_put(rt);
1198                 /*
1199                  * Some IPv4 replies get local address from routes,
1200                  * not from iph, so while we DNAT after routing
1201                  * we need this second input/output route.
1202                  */
1203                 if (!__ip_vs_reroute_locally(skb))
1204                         goto tx_error;
1205         }
1206
1207         /* Another hack: avoid icmp_send in ip_fragment */
1208         skb->local_df = 1;
1209
1210         IP_VS_XMIT_NAT(NFPROTO_IPV4, skb, cp, local);
1211
1212         rc = NF_STOLEN;
1213         goto out;
1214
1215   tx_error_icmp:
1216         dst_link_failure(skb);
1217   tx_error:
1218         dev_kfree_skb(skb);
1219         rc = NF_STOLEN;
1220   out:
1221         LeaveFunction(10);
1222         return rc;
1223   tx_error_put:
1224         ip_rt_put(rt);
1225         goto tx_error;
1226 }
1227
1228 #ifdef CONFIG_IP_VS_IPV6
1229 int
1230 ip_vs_icmp_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
1231                 struct ip_vs_protocol *pp, int offset)
1232 {
1233         struct rt6_info *rt;    /* Route to the other host */
1234         int mtu;
1235         int rc;
1236         int local;
1237
1238         EnterFunction(10);
1239
1240         /* The ICMP packet for VS/TUN, VS/DR and LOCALNODE will be
1241            forwarded directly here, because there is no need to
1242            translate address/port back */
1243         if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ) {
1244                 if (cp->packet_xmit)
1245                         rc = cp->packet_xmit(skb, cp, pp);
1246                 else
1247                         rc = NF_ACCEPT;
1248                 /* do not touch skb anymore */
1249                 atomic_inc(&cp->in_pkts);
1250                 goto out;
1251         }
1252
1253         /*
1254          * mangle and send the packet here (only for VS/NAT)
1255          */
1256
1257         if (!(rt = __ip_vs_get_out_rt_v6(skb, cp->dest, &cp->daddr.in6, NULL,
1258                                          0, 1|2|4)))
1259                 goto tx_error_icmp;
1260
1261         local = __ip_vs_is_local_route6(rt);
1262         /*
1263          * Avoid duplicate tuple in reply direction for NAT traffic
1264          * to local address when connection is sync-ed
1265          */
1266 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1267         if (cp->flags & IP_VS_CONN_F_SYNC && local) {
1268                 enum ip_conntrack_info ctinfo;
1269                 struct nf_conn *ct = ct = nf_ct_get(skb, &ctinfo);
1270
1271                 if (ct && !nf_ct_is_untracked(ct)) {
1272                         IP_VS_DBG(10, "%s(): "
1273                                   "stopping DNAT to local address %pI6\n",
1274                                   __func__, &cp->daddr.in6);
1275                         goto tx_error_put;
1276                 }
1277         }
1278 #endif
1279
1280         /* From world but DNAT to loopback address? */
1281         if (local && skb->dev && !(skb->dev->flags & IFF_LOOPBACK) &&
1282             ipv6_addr_type(&rt->rt6i_dst.addr) & IPV6_ADDR_LOOPBACK) {
1283                 IP_VS_DBG(1, "%s(): "
1284                           "stopping DNAT to loopback %pI6\n",
1285                           __func__, &cp->daddr.in6);
1286                 goto tx_error_put;
1287         }
1288
1289         /* MTU checking */
1290         mtu = dst_mtu(&rt->dst);
1291         if (skb->len > mtu) {
1292                 if (!skb->dev) {
1293                         struct net *net = dev_net(skb_dst(skb)->dev);
1294
1295                         skb->dev = net->loopback_dev;
1296                 }
1297                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
1298                 IP_VS_DBG_RL("%s(): frag needed\n", __func__);
1299                 goto tx_error_put;
1300         }
1301
1302         /* copy-on-write the packet before mangling it */
1303         if (!skb_make_writable(skb, offset))
1304                 goto tx_error_put;
1305
1306         if (skb_cow(skb, rt->dst.dev->hard_header_len))
1307                 goto tx_error_put;
1308
1309         ip_vs_nat_icmp_v6(skb, pp, cp, 0);
1310
1311         if (!local || !skb->dev) {
1312                 /* drop the old route when skb is not shared */
1313                 skb_dst_drop(skb);
1314                 skb_dst_set(skb, &rt->dst);
1315         } else {
1316                 /* destined to loopback, do we need to change route? */
1317                 dst_release(&rt->dst);
1318         }
1319
1320         /* Another hack: avoid icmp_send in ip_fragment */
1321         skb->local_df = 1;
1322
1323         IP_VS_XMIT_NAT(NFPROTO_IPV6, skb, cp, local);
1324
1325         rc = NF_STOLEN;
1326         goto out;
1327
1328 tx_error_icmp:
1329         dst_link_failure(skb);
1330 tx_error:
1331         dev_kfree_skb(skb);
1332         rc = NF_STOLEN;
1333 out:
1334         LeaveFunction(10);
1335         return rc;
1336 tx_error_put:
1337         dst_release(&rt->dst);
1338         goto tx_error;
1339 }
1340 #endif