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                                 .fl4_dst = dest->addr.ip,
 100                                 .fl4_tos = rtos,
 101                         };
 102
 103                         if (ip_route_output_key(net, &rt, &fl)) {
 104                                 spin_unlock(&dest->dst_lock);
 105                                 IP_VS_DBG_RL("ip_route_output error, dest: %pI4\n",
 106                                              &dest->addr.ip);
 107                                 return NULL;
 108                         }
 109                         __ip_vs_dst_set(dest, rtos, dst_clone(&rt->dst), 0);
 110                         IP_VS_DBG(10, "new dst %pI4, refcnt=%d, rtos=%X\n",
 111                                   &dest->addr.ip,
 112                                   atomic_read(&rt->dst.__refcnt), rtos);
 113                 }
 114                 spin_unlock(&dest->dst_lock);
 115         } else {
 116                 struct flowi fl = {
 117                         .fl4_dst = daddr,
 118                         .fl4_tos = rtos,
 119                 };
 120
 121                 if (ip_route_output_key(net, &rt, &fl)) {
 122                         IP_VS_DBG_RL("ip_route_output error, dest: %pI4\n",
 123                                      &daddr);
 124                         return NULL;
 125                 }
 126         }
 127
 128         local = rt->rt_flags & RTCF_LOCAL;
 129         if (!((local ? 1 : 2) & rt_mode)) {
 130                 IP_VS_DBG_RL("Stopping traffic to %s address, dest: %pI4\n",
 131                              (rt->rt_flags & RTCF_LOCAL) ?
 132                              "local":"non-local", &rt->rt_dst);
 133                 ip_rt_put(rt);
 134                 return NULL;
 135         }
 136         if (local && !(rt_mode & 4) && !((ort = skb_rtable(skb)) &&
 137                                          ort->rt_flags & RTCF_LOCAL)) {
 138                 IP_VS_DBG_RL("Redirect from non-local address %pI4 to local "
 139                              "requires NAT method, dest: %pI4\n",
 140                              &ip_hdr(skb)->daddr, &rt->rt_dst);
 141                 ip_rt_put(rt);
 142                 return NULL;
 143         }
 144         if (unlikely(!local && ipv4_is_loopback(ip_hdr(skb)->saddr))) {
 145                 IP_VS_DBG_RL("Stopping traffic from loopback address %pI4 "
 146                              "to non-local address, dest: %pI4\n",
 147                              &ip_hdr(skb)->saddr, &rt->rt_dst);
 148                 ip_rt_put(rt);
 149                 return NULL;
 150         }
 151
 152         return rt;
 153 }
 154
 155 /* Reroute packet to local IPv4 stack after DNAT */
 156 static int
 157 __ip_vs_reroute_locally(struct sk_buff *skb)
 158 {
 159         struct rtable *rt = skb_rtable(skb);
 160         struct net_device *dev = rt->dst.dev;
 161         struct net *net = dev_net(dev);
 162         struct iphdr *iph = ip_hdr(skb);
 163
 164         if (rt_is_input_route(rt)) {
 165                 unsigned long orefdst = skb->_skb_refdst;
 166
 167                 if (ip_route_input(skb, iph->daddr, iph->saddr,
 168                                    iph->tos, skb->dev))
 169                         return 0;
 170                 refdst_drop(orefdst);
 171         } else {
 172                 struct flowi fl = {
 173                         .fl4_dst = iph->daddr,
 174                         .fl4_src = iph->saddr,
 175                         .fl4_tos = RT_TOS(iph->tos),
 176                         .mark = skb->mark,
 177                 };
 178                 struct rtable *rt;
 179
 180                 if (ip_route_output_key(net, &rt, &fl))
 181                         return 0;
 182                 if (!(rt->rt_flags & RTCF_LOCAL)) {
 183                         ip_rt_put(rt);
 184                         return 0;
 185                 }
 186                 /* Drop old route. */
 187                 skb_dst_drop(skb);
 188                 skb_dst_set(skb, &rt->dst);
 189         }
 190         return 1;
 191 }
 192
 193 #ifdef CONFIG_IP_VS_IPV6
 194
 195 static inline int __ip_vs_is_local_route6(struct rt6_info *rt)
 196 {
 197         return rt->rt6i_dev && rt->rt6i_dev->flags & IFF_LOOPBACK;
 198 }
 199
 200 static struct dst_entry *
 201 __ip_vs_route_output_v6(struct net *net, struct in6_addr *daddr,
 202                         struct in6_addr *ret_saddr, int do_xfrm)
 203 {
 204         struct dst_entry *dst;
 205         struct flowi fl = {
 206                 .fl6_dst = *daddr,
 207         };
 208
 209         dst = ip6_route_output(net, NULL, &fl);
 210         if (dst->error)
 211                 goto out_err;
 212         if (!ret_saddr)
 213                 return dst;
 214         if (ipv6_addr_any(&fl.fl6_src) &&
 215             ipv6_dev_get_saddr(net, ip6_dst_idev(dst)->dev,
 216                                &fl.fl6_dst, 0, &fl.fl6_src) < 0)
 217                 goto out_err;
 218         if (do_xfrm && xfrm_lookup(net, &dst, &fl, NULL, 0) < 0)
 219                 goto out_err;
 220         ipv6_addr_copy(ret_saddr, &fl.fl6_src);
 221         return dst;
 222
 223 out_err:
 224         dst_release(dst);
 225         IP_VS_DBG_RL("ip6_route_output error, dest: %pI6\n", daddr);
 226         return NULL;
 227 }
 228
 229 /*
 230  * Get route to destination or remote server
 231  * rt_mode: flags, &1=Allow local dest, &2=Allow non-local dest,
 232  *          &4=Allow redirect from remote daddr to local
 233  */
 234 static struct rt6_info *
 235 __ip_vs_get_out_rt_v6(struct sk_buff *skb, struct ip_vs_dest *dest,
 236                       struct in6_addr *daddr, struct in6_addr *ret_saddr,
 237                       int do_xfrm, int rt_mode)
 238 {
 239         struct net *net = dev_net(skb_dst(skb)->dev);
 240         struct rt6_info *rt;                    /* Route to the other host */
 241         struct rt6_info *ort;                   /* Original route */
 242         struct dst_entry *dst;
 243         int local;
 244
 245         if (dest) {
 246                 spin_lock(&dest->dst_lock);
 247                 rt = (struct rt6_info *)__ip_vs_dst_check(dest, 0);
 248                 if (!rt) {
 249                         u32 cookie;
 250
 251                         dst = __ip_vs_route_output_v6(net, &dest->addr.in6,
 252                                                       &dest->dst_saddr,
 253                                                       do_xfrm);
 254                         if (!dst) {
 255                                 spin_unlock(&dest->dst_lock);
 256                                 return NULL;
 257                         }
 258                         rt = (struct rt6_info *) dst;
 259                         cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
 260                         __ip_vs_dst_set(dest, 0, dst_clone(&rt->dst), cookie);
 261                         IP_VS_DBG(10, "new dst %pI6, src %pI6, refcnt=%d\n",
 262                                   &dest->addr.in6, &dest->dst_saddr,
 263                                   atomic_read(&rt->dst.__refcnt));
 264                 }
 265                 if (ret_saddr)
 266                         ipv6_addr_copy(ret_saddr, &dest->dst_saddr);
 267                 spin_unlock(&dest->dst_lock);
 268         } else {
 269                 dst = __ip_vs_route_output_v6(net, daddr, ret_saddr, do_xfrm);
 270                 if (!dst)
 271                         return NULL;
 272                 rt = (struct rt6_info *) dst;
 273         }
 274
 275         local = __ip_vs_is_local_route6(rt);
 276         if (!((local ? 1 : 2) & rt_mode)) {
 277                 IP_VS_DBG_RL("Stopping traffic to %s address, dest: %pI6\n",
 278                              local ? "local":"non-local", daddr);
 279                 dst_release(&rt->dst);
 280                 return NULL;
 281         }
 282         if (local && !(rt_mode & 4) &&
 283             !((ort = (struct rt6_info *) skb_dst(skb)) &&
 284               __ip_vs_is_local_route6(ort))) {
 285                 IP_VS_DBG_RL("Redirect from non-local address %pI6 to local "
 286                              "requires NAT method, dest: %pI6\n",
 287                              &ipv6_hdr(skb)->daddr, daddr);
 288                 dst_release(&rt->dst);
 289                 return NULL;
 290         }
 291         if (unlikely(!local && (!skb->dev || skb->dev->flags & IFF_LOOPBACK) &&
 292                      ipv6_addr_type(&ipv6_hdr(skb)->saddr) &
 293                                     IPV6_ADDR_LOOPBACK)) {
 294                 IP_VS_DBG_RL("Stopping traffic from loopback address %pI6 "
 295                              "to non-local address, dest: %pI6\n",
 296                              &ipv6_hdr(skb)->saddr, daddr);
 297                 dst_release(&rt->dst);
 298                 return NULL;
 299         }
 300
 301         return rt;
 302 }
 303 #endif
 304
 305
 306 /*
 307  *      Release dest->dst_cache before a dest is removed
 308  */
 309 void
 310 ip_vs_dst_reset(struct ip_vs_dest *dest)
 311 {
 312         struct dst_entry *old_dst;
 313
 314         old_dst = dest->dst_cache;
 315         dest->dst_cache = NULL;
 316         dst_release(old_dst);
 317 }
 318
 319 #define IP_VS_XMIT_TUNNEL(skb, cp)                              \
 320 ({                                                              \
 321         int __ret = NF_ACCEPT;                                  \
 322                                                                 \
 323         (skb)->ipvs_property = 1;                               \
 324         if (unlikely((cp)->flags & IP_VS_CONN_F_NFCT))          \
 325                 __ret = ip_vs_confirm_conntrack(skb, cp);       \
 326         if (__ret == NF_ACCEPT) {                               \
 327                 nf_reset(skb);                                  \
 328                 skb_forward_csum(skb);                          \
 329         }                                                       \
 330         __ret;                                                  \
 331 })
 332
 333 #define IP_VS_XMIT_NAT(pf, skb, cp, local)              \
 334 do {                                                    \
 335         (skb)->ipvs_property = 1;                       \
 336         if (likely(!((cp)->flags & IP_VS_CONN_F_NFCT))) \
 337                 ip_vs_notrack(skb);                     \
 338         else                                            \
 339                 ip_vs_update_conntrack(skb, cp, 1);     \
 340         if (local)                                      \
 341                 return NF_ACCEPT;                       \
 342         skb_forward_csum(skb);                          \
 343         NF_HOOK(pf, NF_INET_LOCAL_OUT, (skb), NULL,     \
 344                 skb_dst(skb)->dev, dst_output);         \
 345 } while (0)
 346
 347 #define IP_VS_XMIT(pf, skb, cp, local)                  \
 348 do {                                                    \
 349         (skb)->ipvs_property = 1;                       \
 350         if (likely(!((cp)->flags & IP_VS_CONN_F_NFCT))) \
 351                 ip_vs_notrack(skb);                     \
 352         if (local)                                      \
 353                 return NF_ACCEPT;                       \
 354         skb_forward_csum(skb);                          \
 355         NF_HOOK(pf, NF_INET_LOCAL_OUT, (skb), NULL,     \
 356                 skb_dst(skb)->dev, dst_output);         \
 357 } while (0)
 358
 359
 360 /*
 361  *      NULL transmitter (do nothing except return NF_ACCEPT)
 362  */
 363 int
 364 ip_vs_null_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 365                 struct ip_vs_protocol *pp)
 366 {
 367         /* we do not touch skb and do not need pskb ptr */
 368         IP_VS_XMIT(NFPROTO_IPV4, skb, cp, 1);
 369 }
 370
 371
 372 /*
 373  *      Bypass transmitter
 374  *      Let packets bypass the destination when the destination is not
 375  *      available, it may be only used in transparent cache cluster.
 376  */
 377 int
 378 ip_vs_bypass_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 379                   struct ip_vs_protocol *pp)
 380 {
 381         struct rtable *rt;                      /* Route to the other host */
 382         struct iphdr  *iph = ip_hdr(skb);
 383         int    mtu;
 384
 385         EnterFunction(10);
 386
 387         if (!(rt = __ip_vs_get_out_rt(skb, NULL, iph->daddr,
 388                                       RT_TOS(iph->tos), 2)))
 389                 goto tx_error_icmp;
 390
 391         /* MTU checking */
 392         mtu = dst_mtu(&rt->dst);
 393         if ((skb->len > mtu) && (iph->frag_off & htons(IP_DF))) {
 394                 ip_rt_put(rt);
 395                 icmp_send(skb, ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED, htonl(mtu));
 396                 IP_VS_DBG_RL("%s(): frag needed\n", __func__);
 397                 goto tx_error;
 398         }
 399
 400         /*
 401          * Call ip_send_check because we are not sure it is called
 402          * after ip_defrag. Is copy-on-write needed?
 403          */
 404         if (unlikely((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)) {
 405                 ip_rt_put(rt);
 406                 return NF_STOLEN;
 407         }
 408         ip_send_check(ip_hdr(skb));
 409
 410         /* drop old route */
 411         skb_dst_drop(skb);
 412         skb_dst_set(skb, &rt->dst);
 413
 414         /* Another hack: avoid icmp_send in ip_fragment */
 415         skb->local_df = 1;
 416
 417         IP_VS_XMIT(NFPROTO_IPV4, skb, cp, 0);
 418
 419         LeaveFunction(10);
 420         return NF_STOLEN;
 421
 422  tx_error_icmp:
 423         dst_link_failure(skb);
 424  tx_error:
 425         kfree_skb(skb);
 426         LeaveFunction(10);
 427         return NF_STOLEN;
 428 }
 429
 430 #ifdef CONFIG_IP_VS_IPV6
 431 int
 432 ip_vs_bypass_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
 433                      struct ip_vs_protocol *pp)
 434 {
 435         struct rt6_info *rt;                    /* Route to the other host */
 436         struct ipv6hdr  *iph = ipv6_hdr(skb);
 437         int    mtu;
 438
 439         EnterFunction(10);
 440
 441         if (!(rt = __ip_vs_get_out_rt_v6(skb, NULL, &iph->daddr, NULL, 0, 2)))
 442                 goto tx_error_icmp;
 443
 444         /* MTU checking */
 445         mtu = dst_mtu(&rt->dst);
 446         if (skb->len > mtu) {
 447                 if (!skb->dev) {
 448                         struct net *net = dev_net(skb_dst(skb)->dev);
 449
 450                         skb->dev = net->loopback_dev;
 451                 }
 452                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 453                 dst_release(&rt->dst);
 454                 IP_VS_DBG_RL("%s(): frag needed\n", __func__);
 455                 goto tx_error;
 456         }
 457
 458         /*
 459          * Call ip_send_check because we are not sure it is called
 460          * after ip_defrag. Is copy-on-write needed?
 461          */
 462         skb = skb_share_check(skb, GFP_ATOMIC);
 463         if (unlikely(skb == NULL)) {
 464                 dst_release(&rt->dst);
 465                 return NF_STOLEN;
 466         }
 467
 468         /* drop old route */
 469         skb_dst_drop(skb);
 470         skb_dst_set(skb, &rt->dst);
 471
 472         /* Another hack: avoid icmp_send in ip_fragment */
 473         skb->local_df = 1;
 474
 475         IP_VS_XMIT(NFPROTO_IPV6, skb, cp, 0);
 476
 477         LeaveFunction(10);
 478         return NF_STOLEN;
 479
 480  tx_error_icmp:
 481         dst_link_failure(skb);
 482  tx_error:
 483         kfree_skb(skb);
 484         LeaveFunction(10);
 485         return NF_STOLEN;
 486 }
 487 #endif
 488
 489 /*
 490  *      NAT transmitter (only for outside-to-inside nat forwarding)
 491  *      Not used for related ICMP
 492  */
 493 int
 494 ip_vs_nat_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 495                struct ip_vs_protocol *pp)
 496 {
 497         struct rtable *rt;              /* Route to the other host */
 498         int mtu;
 499         struct iphdr *iph = ip_hdr(skb);
 500         int local;
 501
 502         EnterFunction(10);
 503
 504         /* check if it is a connection of no-client-port */
 505         if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT)) {
 506                 __be16 _pt, *p;
 507                 p = skb_header_pointer(skb, iph->ihl*4, sizeof(_pt), &_pt);
 508                 if (p == NULL)
 509                         goto tx_error;
 510                 ip_vs_conn_fill_cport(cp, *p);
 511                 IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
 512         }
 513
 514         if (!(rt = __ip_vs_get_out_rt(skb, cp->dest, cp->daddr.ip,
 515                                       RT_TOS(iph->tos), 1|2|4)))
 516                 goto tx_error_icmp;
 517         local = rt->rt_flags & RTCF_LOCAL;
 518         /*
 519          * Avoid duplicate tuple in reply direction for NAT traffic
 520          * to local address when connection is sync-ed
 521          */
 522 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 523         if (cp->flags & IP_VS_CONN_F_SYNC && local) {
 524                 enum ip_conntrack_info ctinfo;
 525                 struct nf_conn *ct = ct = nf_ct_get(skb, &ctinfo);
 526
 527                 if (ct && !nf_ct_is_untracked(ct)) {
 528                         IP_VS_DBG_RL_PKT(10, AF_INET, pp, skb, 0,
 529                                          "ip_vs_nat_xmit(): "
 530                                          "stopping DNAT to local address");
 531                         goto tx_error_put;
 532                 }
 533         }
 534 #endif
 535
 536         /* From world but DNAT to loopback address? */
 537         if (local && ipv4_is_loopback(rt->rt_dst) &&
 538             rt_is_input_route(skb_rtable(skb))) {
 539                 IP_VS_DBG_RL_PKT(1, AF_INET, pp, skb, 0, "ip_vs_nat_xmit(): "
 540                                  "stopping DNAT to loopback address");
 541                 goto tx_error_put;
 542         }
 543
 544         /* MTU checking */
 545         mtu = dst_mtu(&rt->dst);
 546         if ((skb->len > mtu) && (iph->frag_off & htons(IP_DF))) {
 547                 icmp_send(skb, ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED, htonl(mtu));
 548                 IP_VS_DBG_RL_PKT(0, AF_INET, pp, skb, 0,
 549                                  "ip_vs_nat_xmit(): frag needed for");
 550                 goto tx_error_put;
 551         }
 552
 553         /* copy-on-write the packet before mangling it */
 554         if (!skb_make_writable(skb, sizeof(struct iphdr)))
 555                 goto tx_error_put;
 556
 557         if (skb_cow(skb, rt->dst.dev->hard_header_len))
 558                 goto tx_error_put;
 559
 560         /* mangle the packet */
 561         if (pp->dnat_handler && !pp->dnat_handler(skb, pp, cp))
 562                 goto tx_error_put;
 563         ip_hdr(skb)->daddr = cp->daddr.ip;
 564         ip_send_check(ip_hdr(skb));
 565
 566         if (!local) {
 567                 /* drop old route */
 568                 skb_dst_drop(skb);
 569                 skb_dst_set(skb, &rt->dst);
 570         } else {
 571                 ip_rt_put(rt);
 572                 /*
 573                  * Some IPv4 replies get local address from routes,
 574                  * not from iph, so while we DNAT after routing
 575                  * we need this second input/output route.
 576                  */
 577                 if (!__ip_vs_reroute_locally(skb))
 578                         goto tx_error;
 579         }
 580
 581         IP_VS_DBG_PKT(10, AF_INET, pp, skb, 0, "After DNAT");
 582
 583         /* FIXME: when application helper enlarges the packet and the length
 584            is larger than the MTU of outgoing device, there will be still
 585            MTU problem. */
 586
 587         /* Another hack: avoid icmp_send in ip_fragment */
 588         skb->local_df = 1;
 589
 590         IP_VS_XMIT_NAT(NFPROTO_IPV4, skb, cp, local);
 591
 592         LeaveFunction(10);
 593         return NF_STOLEN;
 594
 595   tx_error_icmp:
 596         dst_link_failure(skb);
 597   tx_error:
 598         kfree_skb(skb);
 599         LeaveFunction(10);
 600         return NF_STOLEN;
 601   tx_error_put:
 602         ip_rt_put(rt);
 603         goto tx_error;
 604 }
 605
 606 #ifdef CONFIG_IP_VS_IPV6
 607 int
 608 ip_vs_nat_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
 609                   struct ip_vs_protocol *pp)
 610 {
 611         struct rt6_info *rt;            /* Route to the other host */
 612         int mtu;
 613         int local;
 614
 615         EnterFunction(10);
 616
 617         /* check if it is a connection of no-client-port */
 618         if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT)) {
 619                 __be16 _pt, *p;
 620                 p = skb_header_pointer(skb, sizeof(struct ipv6hdr),
 621                                        sizeof(_pt), &_pt);
 622                 if (p == NULL)
 623                         goto tx_error;
 624                 ip_vs_conn_fill_cport(cp, *p);
 625                 IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
 626         }
 627
 628         if (!(rt = __ip_vs_get_out_rt_v6(skb, cp->dest, &cp->daddr.in6, NULL,
 629                                          0, 1|2|4)))
 630                 goto tx_error_icmp;
 631         local = __ip_vs_is_local_route6(rt);
 632         /*
 633          * Avoid duplicate tuple in reply direction for NAT traffic
 634          * to local address when connection is sync-ed
 635          */
 636 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 637         if (cp->flags & IP_VS_CONN_F_SYNC && local) {
 638                 enum ip_conntrack_info ctinfo;
 639                 struct nf_conn *ct = ct = nf_ct_get(skb, &ctinfo);
 640
 641                 if (ct && !nf_ct_is_untracked(ct)) {
 642                         IP_VS_DBG_RL_PKT(10, AF_INET6, pp, skb, 0,
 643                                          "ip_vs_nat_xmit_v6(): "
 644                                          "stopping DNAT to local address");
 645                         goto tx_error_put;
 646                 }
 647         }
 648 #endif
 649
 650         /* From world but DNAT to loopback address? */
 651         if (local && skb->dev && !(skb->dev->flags & IFF_LOOPBACK) &&
 652             ipv6_addr_type(&rt->rt6i_dst.addr) & IPV6_ADDR_LOOPBACK) {
 653                 IP_VS_DBG_RL_PKT(1, AF_INET6, pp, skb, 0,
 654                                  "ip_vs_nat_xmit_v6(): "
 655                                  "stopping DNAT to loopback address");
 656                 goto tx_error_put;
 657         }
 658
 659         /* MTU checking */
 660         mtu = dst_mtu(&rt->dst);
 661         if (skb->len > mtu) {
 662                 if (!skb->dev) {
 663                         struct net *net = dev_net(skb_dst(skb)->dev);
 664
 665                         skb->dev = net->loopback_dev;
 666                 }
 667                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 668                 IP_VS_DBG_RL_PKT(0, AF_INET6, pp, skb, 0,
 669                                  "ip_vs_nat_xmit_v6(): frag needed for");
 670                 goto tx_error_put;
 671         }
 672
 673         /* copy-on-write the packet before mangling it */
 674         if (!skb_make_writable(skb, sizeof(struct ipv6hdr)))
 675                 goto tx_error_put;
 676
 677         if (skb_cow(skb, rt->dst.dev->hard_header_len))
 678                 goto tx_error_put;
 679
 680         /* mangle the packet */
 681         if (pp->dnat_handler && !pp->dnat_handler(skb, pp, cp))
 682                 goto tx_error;
 683         ipv6_addr_copy(&ipv6_hdr(skb)->daddr, &cp->daddr.in6);
 684
 685         if (!local || !skb->dev) {
 686                 /* drop the old route when skb is not shared */
 687                 skb_dst_drop(skb);
 688                 skb_dst_set(skb, &rt->dst);
 689         } else {
 690                 /* destined to loopback, do we need to change route? */
 691                 dst_release(&rt->dst);
 692         }
 693
 694         IP_VS_DBG_PKT(10, AF_INET6, pp, skb, 0, "After DNAT");
 695
 696         /* FIXME: when application helper enlarges the packet and the length
 697            is larger than the MTU of outgoing device, there will be still
 698            MTU problem. */
 699
 700         /* Another hack: avoid icmp_send in ip_fragment */
 701         skb->local_df = 1;
 702
 703         IP_VS_XMIT_NAT(NFPROTO_IPV6, skb, cp, local);
 704
 705         LeaveFunction(10);
 706         return NF_STOLEN;
 707
 708 tx_error_icmp:
 709         dst_link_failure(skb);
 710 tx_error:
 711         LeaveFunction(10);
 712         kfree_skb(skb);
 713         return NF_STOLEN;
 714 tx_error_put:
 715         dst_release(&rt->dst);
 716         goto tx_error;
 717 }
 718 #endif
 719
 720
 721 /*
 722  *   IP Tunneling transmitter
 723  *
 724  *   This function encapsulates the packet in a new IP packet, its
 725  *   destination will be set to cp->daddr. Most code of this function
 726  *   is taken from ipip.c.
 727  *
 728  *   It is used in VS/TUN cluster. The load balancer selects a real
 729  *   server from a cluster based on a scheduling algorithm,
 730  *   encapsulates the request packet and forwards it to the selected
 731  *   server. For example, all real servers are configured with
 732  *   "ifconfig tunl0 <Virtual IP Address> up". When the server receives
 733  *   the encapsulated packet, it will decapsulate the packet, processe
 734  *   the request and return the response packets directly to the client
 735  *   without passing the load balancer. This can greatly increase the
 736  *   scalability of virtual server.
 737  *
 738  *   Used for ANY protocol
 739  */
 740 int
 741 ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 742                   struct ip_vs_protocol *pp)
 743 {
 744         struct rtable *rt;                      /* Route to the other host */
 745         struct net_device *tdev;                /* Device to other host */
 746         struct iphdr  *old_iph = ip_hdr(skb);
 747         u8     tos = old_iph->tos;
 748         __be16 df = old_iph->frag_off;
 749         struct iphdr  *iph;                     /* Our new IP header */
 750         unsigned int max_headroom;              /* The extra header space needed */
 751         int    mtu;
 752         int ret;
 753
 754         EnterFunction(10);
 755
 756         if (!(rt = __ip_vs_get_out_rt(skb, cp->dest, cp->daddr.ip,
 757                                       RT_TOS(tos), 1|2)))
 758                 goto tx_error_icmp;
 759         if (rt->rt_flags & RTCF_LOCAL) {
 760                 ip_rt_put(rt);
 761                 IP_VS_XMIT(NFPROTO_IPV4, skb, cp, 1);
 762         }
 763
 764         tdev = rt->dst.dev;
 765
 766         mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
 767         if (mtu < 68) {
 768                 IP_VS_DBG_RL("%s(): mtu less than 68\n", __func__);
 769                 goto tx_error_put;
 770         }
 771         if (skb_dst(skb))
 772                 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
 773
 774         df |= (old_iph->frag_off & htons(IP_DF));
 775
 776         if ((old_iph->frag_off & htons(IP_DF))
 777             && mtu < ntohs(old_iph->tot_len)) {
 778                 icmp_send(skb, ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED, htonl(mtu));
 779                 IP_VS_DBG_RL("%s(): frag needed\n", __func__);
 780                 goto tx_error_put;
 781         }
 782
 783         /*
 784          * Okay, now see if we can stuff it in the buffer as-is.
 785          */
 786         max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct iphdr);
 787
 788         if (skb_headroom(skb) < max_headroom
 789             || skb_cloned(skb) || skb_shared(skb)) {
 790                 struct sk_buff *new_skb =
 791                         skb_realloc_headroom(skb, max_headroom);
 792                 if (!new_skb) {
 793                         ip_rt_put(rt);
 794                         kfree_skb(skb);
 795                         IP_VS_ERR_RL("%s(): no memory\n", __func__);
 796                         return NF_STOLEN;
 797                 }
 798                 kfree_skb(skb);
 799                 skb = new_skb;
 800                 old_iph = ip_hdr(skb);
 801         }
 802
 803         skb->transport_header = skb->network_header;
 804
 805         /* fix old IP header checksum */
 806         ip_send_check(old_iph);
 807
 808         skb_push(skb, sizeof(struct iphdr));
 809         skb_reset_network_header(skb);
 810         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 811
 812         /* drop old route */
 813         skb_dst_drop(skb);
 814         skb_dst_set(skb, &rt->dst);
 815
 816         /*
 817          *      Push down and install the IPIP header.
 818          */
 819         iph                     =       ip_hdr(skb);
 820         iph->version            =       4;
 821         iph->ihl                =       sizeof(struct iphdr)>>2;
 822         iph->frag_off           =       df;
 823         iph->protocol           =       IPPROTO_IPIP;
 824         iph->tos                =       tos;
 825         iph->daddr              =       rt->rt_dst;
 826         iph->saddr              =       rt->rt_src;
 827         iph->ttl                =       old_iph->ttl;
 828         ip_select_ident(iph, &rt->dst, NULL);
 829
 830         /* Another hack: avoid icmp_send in ip_fragment */
 831         skb->local_df = 1;
 832
 833         ret = IP_VS_XMIT_TUNNEL(skb, cp);
 834         if (ret == NF_ACCEPT)
 835                 ip_local_out(skb);
 836         else if (ret == NF_DROP)
 837                 kfree_skb(skb);
 838
 839         LeaveFunction(10);
 840
 841         return NF_STOLEN;
 842
 843   tx_error_icmp:
 844         dst_link_failure(skb);
 845   tx_error:
 846         kfree_skb(skb);
 847         LeaveFunction(10);
 848         return NF_STOLEN;
 849 tx_error_put:
 850         ip_rt_put(rt);
 851         goto tx_error;
 852 }
 853
 854 #ifdef CONFIG_IP_VS_IPV6
 855 int
 856 ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
 857                      struct ip_vs_protocol *pp)
 858 {
 859         struct rt6_info *rt;            /* Route to the other host */
 860         struct in6_addr saddr;          /* Source for tunnel */
 861         struct net_device *tdev;        /* Device to other host */
 862         struct ipv6hdr  *old_iph = ipv6_hdr(skb);
 863         struct ipv6hdr  *iph;           /* Our new IP header */
 864         unsigned int max_headroom;      /* The extra header space needed */
 865         int    mtu;
 866         int ret;
 867
 868         EnterFunction(10);
 869
 870         if (!(rt = __ip_vs_get_out_rt_v6(skb, cp->dest, &cp->daddr.in6,
 871                                          &saddr, 1, 1|2)))
 872                 goto tx_error_icmp;
 873         if (__ip_vs_is_local_route6(rt)) {
 874                 dst_release(&rt->dst);
 875                 IP_VS_XMIT(NFPROTO_IPV6, skb, cp, 1);
 876         }
 877
 878         tdev = rt->dst.dev;
 879
 880         mtu = dst_mtu(&rt->dst) - sizeof(struct ipv6hdr);
 881         if (mtu < IPV6_MIN_MTU) {
 882                 IP_VS_DBG_RL("%s(): mtu less than %d\n", __func__,
 883                              IPV6_MIN_MTU);
 884                 goto tx_error_put;
 885         }
 886         if (skb_dst(skb))
 887                 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
 888
 889         if (mtu < ntohs(old_iph->payload_len) + sizeof(struct ipv6hdr)) {
 890                 if (!skb->dev) {
 891                         struct net *net = dev_net(skb_dst(skb)->dev);
 892
 893                         skb->dev = net->loopback_dev;
 894                 }
 895                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 896                 IP_VS_DBG_RL("%s(): frag needed\n", __func__);
 897                 goto tx_error_put;
 898         }
 899
 900         /*
 901          * Okay, now see if we can stuff it in the buffer as-is.
 902          */
 903         max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct ipv6hdr);
 904
 905         if (skb_headroom(skb) < max_headroom
 906             || skb_cloned(skb) || skb_shared(skb)) {
 907                 struct sk_buff *new_skb =
 908                         skb_realloc_headroom(skb, max_headroom);
 909                 if (!new_skb) {
 910                         dst_release(&rt->dst);
 911                         kfree_skb(skb);
 912                         IP_VS_ERR_RL("%s(): no memory\n", __func__);
 913                         return NF_STOLEN;
 914                 }
 915                 kfree_skb(skb);
 916                 skb = new_skb;
 917                 old_iph = ipv6_hdr(skb);
 918         }
 919
 920         skb->transport_header = skb->network_header;
 921
 922         skb_push(skb, sizeof(struct ipv6hdr));
 923         skb_reset_network_header(skb);
 924         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 925
 926         /* drop old route */
 927         skb_dst_drop(skb);
 928         skb_dst_set(skb, &rt->dst);
 929
 930         /*
 931          *      Push down and install the IPIP header.
 932          */
 933         iph                     =       ipv6_hdr(skb);
 934         iph->version            =       6;
 935         iph->nexthdr            =       IPPROTO_IPV6;
 936         iph->payload_len        =       old_iph->payload_len;
 937         be16_add_cpu(&iph->payload_len, sizeof(*old_iph));
 938         iph->priority           =       old_iph->priority;
 939         memset(&iph->flow_lbl, 0, sizeof(iph->flow_lbl));
 940         ipv6_addr_copy(&iph->daddr, &cp->daddr.in6);
 941         ipv6_addr_copy(&iph->saddr, &saddr);
 942         iph->hop_limit          =       old_iph->hop_limit;
 943
 944         /* Another hack: avoid icmp_send in ip_fragment */
 945         skb->local_df = 1;
 946
 947         ret = IP_VS_XMIT_TUNNEL(skb, cp);
 948         if (ret == NF_ACCEPT)
 949                 ip6_local_out(skb);
 950         else if (ret == NF_DROP)
 951                 kfree_skb(skb);
 952
 953         LeaveFunction(10);
 954
 955         return NF_STOLEN;
 956
 957 tx_error_icmp:
 958         dst_link_failure(skb);
 959 tx_error:
 960         kfree_skb(skb);
 961         LeaveFunction(10);
 962         return NF_STOLEN;
 963 tx_error_put:
 964         dst_release(&rt->dst);
 965         goto tx_error;
 966 }
 967 #endif
 968
 969
 970 /*
 971  *      Direct Routing transmitter
 972  *      Used for ANY protocol
 973  */
 974 int
 975 ip_vs_dr_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 976               struct ip_vs_protocol *pp)
 977 {
 978         struct rtable *rt;                      /* Route to the other host */
 979         struct iphdr  *iph = ip_hdr(skb);
 980         int    mtu;
 981
 982         EnterFunction(10);
 983
 984         if (!(rt = __ip_vs_get_out_rt(skb, cp->dest, cp->daddr.ip,
 985                                       RT_TOS(iph->tos), 1|2)))
 986                 goto tx_error_icmp;
 987         if (rt->rt_flags & RTCF_LOCAL) {
 988                 ip_rt_put(rt);
 989                 IP_VS_XMIT(NFPROTO_IPV4, skb, cp, 1);
 990         }
 991
 992         /* MTU checking */
 993         mtu = dst_mtu(&rt->dst);
 994         if ((iph->frag_off & htons(IP_DF)) && skb->len > mtu) {
 995                 icmp_send(skb, ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED, htonl(mtu));
 996                 ip_rt_put(rt);
 997                 IP_VS_DBG_RL("%s(): frag needed\n", __func__);
 998                 goto tx_error;
 999         }
1000
1001         /*
1002          * Call ip_send_check because we are not sure it is called
1003          * after ip_defrag. Is copy-on-write needed?
1004          */
1005         if (unlikely((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)) {
1006                 ip_rt_put(rt);
1007                 return NF_STOLEN;
1008         }
1009         ip_send_check(ip_hdr(skb));
1010
1011         /* drop old route */
1012         skb_dst_drop(skb);
1013         skb_dst_set(skb, &rt->dst);
1014
1015         /* Another hack: avoid icmp_send in ip_fragment */
1016         skb->local_df = 1;
1017
1018         IP_VS_XMIT(NFPROTO_IPV4, skb, cp, 0);
1019
1020         LeaveFunction(10);
1021         return NF_STOLEN;
1022
1023   tx_error_icmp:
1024         dst_link_failure(skb);
1025   tx_error:
1026         kfree_skb(skb);
1027         LeaveFunction(10);
1028         return NF_STOLEN;
1029 }
1030
1031 #ifdef CONFIG_IP_VS_IPV6
1032 int
1033 ip_vs_dr_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
1034                  struct ip_vs_protocol *pp)
1035 {
1036         struct rt6_info *rt;                    /* Route to the other host */
1037         int    mtu;
1038
1039         EnterFunction(10);
1040
1041         if (!(rt = __ip_vs_get_out_rt_v6(skb, cp->dest, &cp->daddr.in6, NULL,
1042                                          0, 1|2)))
1043                 goto tx_error_icmp;
1044         if (__ip_vs_is_local_route6(rt)) {
1045                 dst_release(&rt->dst);
1046                 IP_VS_XMIT(NFPROTO_IPV6, skb, cp, 1);
1047         }
1048
1049         /* MTU checking */
1050         mtu = dst_mtu(&rt->dst);
1051         if (skb->len > mtu) {
1052                 if (!skb->dev) {
1053                         struct net *net = dev_net(skb_dst(skb)->dev);
1054
1055                         skb->dev = net->loopback_dev;
1056                 }
1057                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
1058                 dst_release(&rt->dst);
1059                 IP_VS_DBG_RL("%s(): frag needed\n", __func__);
1060                 goto tx_error;
1061         }
1062
1063         /*
1064          * Call ip_send_check because we are not sure it is called
1065          * after ip_defrag. Is copy-on-write needed?
1066          */
1067         skb = skb_share_check(skb, GFP_ATOMIC);
1068         if (unlikely(skb == NULL)) {
1069                 dst_release(&rt->dst);
1070                 return NF_STOLEN;
1071         }
1072
1073         /* drop old route */
1074         skb_dst_drop(skb);
1075         skb_dst_set(skb, &rt->dst);
1076
1077         /* Another hack: avoid icmp_send in ip_fragment */
1078         skb->local_df = 1;
1079
1080         IP_VS_XMIT(NFPROTO_IPV6, skb, cp, 0);
1081
1082         LeaveFunction(10);
1083         return NF_STOLEN;
1084
1085 tx_error_icmp:
1086         dst_link_failure(skb);
1087 tx_error:
1088         kfree_skb(skb);
1089         LeaveFunction(10);
1090         return NF_STOLEN;
1091 }
1092 #endif
1093
1094
1095 /*
1096  *      ICMP packet transmitter
1097  *      called by the ip_vs_in_icmp
1098  */
1099 int
1100 ip_vs_icmp_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
1101                 struct ip_vs_protocol *pp, int offset)
1102 {
1103         struct rtable   *rt;    /* Route to the other host */
1104         int mtu;
1105         int rc;
1106         int local;
1107
1108         EnterFunction(10);
1109
1110         /* The ICMP packet for VS/TUN, VS/DR and LOCALNODE will be
1111            forwarded directly here, because there is no need to
1112            translate address/port back */
1113         if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ) {
1114                 if (cp->packet_xmit)
1115                         rc = cp->packet_xmit(skb, cp, pp);
1116                 else
1117                         rc = NF_ACCEPT;
1118                 /* do not touch skb anymore */
1119                 atomic_inc(&cp->in_pkts);
1120                 goto out;
1121         }
1122
1123         /*
1124          * mangle and send the packet here (only for VS/NAT)
1125          */
1126
1127         if (!(rt = __ip_vs_get_out_rt(skb, cp->dest, cp->daddr.ip,
1128                                       RT_TOS(ip_hdr(skb)->tos), 1|2|4)))
1129                 goto tx_error_icmp;
1130         local = rt->rt_flags & RTCF_LOCAL;
1131
1132         /*
1133          * Avoid duplicate tuple in reply direction for NAT traffic
1134          * to local address when connection is sync-ed
1135          */
1136 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1137         if (cp->flags & IP_VS_CONN_F_SYNC && local) {
1138                 enum ip_conntrack_info ctinfo;
1139                 struct nf_conn *ct = ct = nf_ct_get(skb, &ctinfo);
1140
1141                 if (ct && !nf_ct_is_untracked(ct)) {
1142                         IP_VS_DBG(10, "%s(): "
1143                                   "stopping DNAT to local address %pI4\n",
1144                                   __func__, &cp->daddr.ip);
1145                         goto tx_error_put;
1146                 }
1147         }
1148 #endif
1149
1150         /* From world but DNAT to loopback address? */
1151         if (local && ipv4_is_loopback(rt->rt_dst) &&
1152             rt_is_input_route(skb_rtable(skb))) {
1153                 IP_VS_DBG(1, "%s(): "
1154                           "stopping DNAT to loopback %pI4\n",
1155                           __func__, &cp->daddr.ip);
1156                 goto tx_error_put;
1157         }
1158
1159         /* MTU checking */
1160         mtu = dst_mtu(&rt->dst);
1161         if ((skb->len > mtu) && (ip_hdr(skb)->frag_off & htons(IP_DF))) {
1162                 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
1163                 IP_VS_DBG_RL("%s(): frag needed\n", __func__);
1164                 goto tx_error_put;
1165         }
1166
1167         /* copy-on-write the packet before mangling it */
1168         if (!skb_make_writable(skb, offset))
1169                 goto tx_error_put;
1170
1171         if (skb_cow(skb, rt->dst.dev->hard_header_len))
1172                 goto tx_error_put;
1173
1174         ip_vs_nat_icmp(skb, pp, cp, 0);
1175
1176         if (!local) {
1177                 /* drop the old route when skb is not shared */
1178                 skb_dst_drop(skb);
1179                 skb_dst_set(skb, &rt->dst);
1180         } else {
1181                 ip_rt_put(rt);
1182                 /*
1183                  * Some IPv4 replies get local address from routes,
1184                  * not from iph, so while we DNAT after routing
1185                  * we need this second input/output route.
1186                  */
1187                 if (!__ip_vs_reroute_locally(skb))
1188                         goto tx_error;
1189         }
1190
1191         /* Another hack: avoid icmp_send in ip_fragment */
1192         skb->local_df = 1;
1193
1194         IP_VS_XMIT_NAT(NFPROTO_IPV4, skb, cp, local);
1195
1196         rc = NF_STOLEN;
1197         goto out;
1198
1199   tx_error_icmp:
1200         dst_link_failure(skb);
1201   tx_error:
1202         dev_kfree_skb(skb);
1203         rc = NF_STOLEN;
1204   out:
1205         LeaveFunction(10);
1206         return rc;
1207   tx_error_put:
1208         ip_rt_put(rt);
1209         goto tx_error;
1210 }
1211
1212 #ifdef CONFIG_IP_VS_IPV6
1213 int
1214 ip_vs_icmp_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
1215                 struct ip_vs_protocol *pp, int offset)
1216 {
1217         struct rt6_info *rt;    /* Route to the other host */
1218         int mtu;
1219         int rc;
1220         int local;
1221
1222         EnterFunction(10);
1223
1224         /* The ICMP packet for VS/TUN, VS/DR and LOCALNODE will be
1225            forwarded directly here, because there is no need to
1226            translate address/port back */
1227         if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ) {
1228                 if (cp->packet_xmit)
1229                         rc = cp->packet_xmit(skb, cp, pp);
1230                 else
1231                         rc = NF_ACCEPT;
1232                 /* do not touch skb anymore */
1233                 atomic_inc(&cp->in_pkts);
1234                 goto out;
1235         }
1236
1237         /*
1238          * mangle and send the packet here (only for VS/NAT)
1239          */
1240
1241         if (!(rt = __ip_vs_get_out_rt_v6(skb, cp->dest, &cp->daddr.in6, NULL,
1242                                          0, 1|2|4)))
1243                 goto tx_error_icmp;
1244
1245         local = __ip_vs_is_local_route6(rt);
1246         /*
1247          * Avoid duplicate tuple in reply direction for NAT traffic
1248          * to local address when connection is sync-ed
1249          */
1250 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1251         if (cp->flags & IP_VS_CONN_F_SYNC && local) {
1252                 enum ip_conntrack_info ctinfo;
1253                 struct nf_conn *ct = ct = nf_ct_get(skb, &ctinfo);
1254
1255                 if (ct && !nf_ct_is_untracked(ct)) {
1256                         IP_VS_DBG(10, "%s(): "
1257                                   "stopping DNAT to local address %pI6\n",
1258                                   __func__, &cp->daddr.in6);
1259                         goto tx_error_put;
1260                 }
1261         }
1262 #endif
1263
1264         /* From world but DNAT to loopback address? */
1265         if (local && skb->dev && !(skb->dev->flags & IFF_LOOPBACK) &&
1266             ipv6_addr_type(&rt->rt6i_dst.addr) & IPV6_ADDR_LOOPBACK) {
1267                 IP_VS_DBG(1, "%s(): "
1268                           "stopping DNAT to loopback %pI6\n",
1269                           __func__, &cp->daddr.in6);
1270                 goto tx_error_put;
1271         }
1272
1273         /* MTU checking */
1274         mtu = dst_mtu(&rt->dst);
1275         if (skb->len > mtu) {
1276                 if (!skb->dev) {
1277                         struct net *net = dev_net(skb_dst(skb)->dev);
1278
1279                         skb->dev = net->loopback_dev;
1280                 }
1281                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
1282                 IP_VS_DBG_RL("%s(): frag needed\n", __func__);
1283                 goto tx_error_put;
1284         }
1285
1286         /* copy-on-write the packet before mangling it */
1287         if (!skb_make_writable(skb, offset))
1288                 goto tx_error_put;
1289
1290         if (skb_cow(skb, rt->dst.dev->hard_header_len))
1291                 goto tx_error_put;
1292
1293         ip_vs_nat_icmp_v6(skb, pp, cp, 0);
1294
1295         if (!local || !skb->dev) {
1296                 /* drop the old route when skb is not shared */
1297                 skb_dst_drop(skb);
1298                 skb_dst_set(skb, &rt->dst);
1299         } else {
1300                 /* destined to loopback, do we need to change route? */
1301                 dst_release(&rt->dst);
1302         }
1303
1304         /* Another hack: avoid icmp_send in ip_fragment */
1305         skb->local_df = 1;
1306
1307         IP_VS_XMIT_NAT(NFPROTO_IPV6, skb, cp, local);
1308
1309         rc = NF_STOLEN;
1310         goto out;
1311
1312 tx_error_icmp:
1313         dst_link_failure(skb);
1314 tx_error:
1315         dev_kfree_skb(skb);
1316         rc = NF_STOLEN;
1317 out:
1318         LeaveFunction(10);
1319         return rc;
1320 tx_error_put:
1321         dst_release(&rt->dst);
1322         goto tx_error;
1323 }
1324 #endif