net/netfilter/ipvs/ip_vs

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This source file includes following definitions.
ip_vs_dest_dst_alloc
ip_vs_dest_dst_free
__ip_vs_dst_set
__ip_vs_dst_check
__mtu_check_toobig_v6
do_output_route4
__ip_vs_is_local_route6
crosses_local_route_boundary
maybe_update_pmtu
ensure_mtu_is_adequate
decrement_ttl
__ip_vs_get_out_rt
__ip_vs_route_output_v6
__ip_vs_get_out_rt_v6
ip_vs_tunnel_xmit_prepare
ip_vs_drop_early_demux_sk
ip_vs_nat_send_or_cont
ip_vs_send_or_cont
ip_vs_null_xmit
ip_vs_bypass_xmit
ip_vs_bypass_xmit_v6
ip_vs_nat_xmit
ip_vs_nat_xmit_v6
ip_vs_prepare_tunneled_skb
__tun_gso_type_mask
ipvs_gue_encap
ipvs_gre_encap
ip_vs_tunnel_xmit
ip_vs_tunnel_xmit_v6
ip_vs_dr_xmit
ip_vs_dr_xmit_v6
ip_vs_icmp_xmit
ip_vs_icmp_xmit_v6
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * ip_vs_xmit.c: various packet transmitters for IPVS
   4  *
   5  * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
   6  *              Julian Anastasov <ja@ssi.bg>
   7  *
   8  * Changes:
   9  *
  10  * Description of forwarding methods:
  11  * - all transmitters are called from LOCAL_IN (remote clients) and
  12  * LOCAL_OUT (local clients) but for ICMP can be called from FORWARD
  13  * - not all connections have destination server, for example,
  14  * connections in backup server when fwmark is used
  15  * - bypass connections use daddr from packet
  16  * - we can use dst without ref while sending in RCU section, we use
  17  * ref when returning NF_ACCEPT for NAT-ed packet via loopback
  18  * LOCAL_OUT rules:
  19  * - skb->dev is NULL, skb->protocol is not set (both are set in POST_ROUTING)
  20  * - skb->pkt_type is not set yet
  21  * - the only place where we can see skb->sk != NULL
  22  */
  23 
  24 #define KMSG_COMPONENT "IPVS"
  25 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  26 
  27 #include <linux/kernel.h>
  28 #include <linux/slab.h>
  29 #include <linux/tcp.h>                  /* for tcphdr */
  30 #include <net/ip.h>
  31 #include <net/gue.h>
  32 #include <net/gre.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/ip_tunnels.h>
  40 #include <net/ip6_checksum.h>
  41 #include <net/addrconf.h>
  42 #include <linux/icmpv6.h>
  43 #include <linux/netfilter.h>
  44 #include <linux/netfilter_ipv4.h>
  45 
  46 #include <net/ip_vs.h>
  47 
  48 enum {
  49         IP_VS_RT_MODE_LOCAL     = 1, /* Allow local dest */
  50         IP_VS_RT_MODE_NON_LOCAL = 2, /* Allow non-local dest */
  51         IP_VS_RT_MODE_RDR       = 4, /* Allow redirect from remote daddr to
  52                                       * local
  53                                       */
  54         IP_VS_RT_MODE_CONNECT   = 8, /* Always bind route to saddr */
  55         IP_VS_RT_MODE_KNOWN_NH  = 16,/* Route via remote addr */
  56         IP_VS_RT_MODE_TUNNEL    = 32,/* Tunnel mode */
  57 };
  58 
  59 static inline struct ip_vs_dest_dst *ip_vs_dest_dst_alloc(void)
  60 {
  61         return kmalloc(sizeof(struct ip_vs_dest_dst), GFP_ATOMIC);
  62 }
  63 
  64 static inline void ip_vs_dest_dst_free(struct ip_vs_dest_dst *dest_dst)
  65 {
  66         kfree(dest_dst);
  67 }
  68 
  69 /*
  70  *      Destination cache to speed up outgoing route lookup
  71  */
  72 static inline void
  73 __ip_vs_dst_set(struct ip_vs_dest *dest, struct ip_vs_dest_dst *dest_dst,
  74                 struct dst_entry *dst, u32 dst_cookie)
  75 {
  76         struct ip_vs_dest_dst *old;
  77 
  78         old = rcu_dereference_protected(dest->dest_dst,
  79                                         lockdep_is_held(&dest->dst_lock));
  80 
  81         if (dest_dst) {
  82                 dest_dst->dst_cache = dst;
  83                 dest_dst->dst_cookie = dst_cookie;
  84         }
  85         rcu_assign_pointer(dest->dest_dst, dest_dst);
  86 
  87         if (old)
  88                 call_rcu(&old->rcu_head, ip_vs_dest_dst_rcu_free);
  89 }
  90 
  91 static inline struct ip_vs_dest_dst *
  92 __ip_vs_dst_check(struct ip_vs_dest *dest)
  93 {
  94         struct ip_vs_dest_dst *dest_dst = rcu_dereference(dest->dest_dst);
  95         struct dst_entry *dst;
  96 
  97         if (!dest_dst)
  98                 return NULL;
  99         dst = dest_dst->dst_cache;
 100         if (dst->obsolete &&
 101             dst->ops->check(dst, dest_dst->dst_cookie) == NULL)
 102                 return NULL;
 103         return dest_dst;
 104 }
 105 
 106 static inline bool
 107 __mtu_check_toobig_v6(const struct sk_buff *skb, u32 mtu)
 108 {
 109         if (IP6CB(skb)->frag_max_size) {
 110                 /* frag_max_size tell us that, this packet have been
 111                  * defragmented by netfilter IPv6 conntrack module.
 112                  */
 113                 if (IP6CB(skb)->frag_max_size > mtu)
 114                         return true; /* largest fragment violate MTU */
 115         }
 116         else if (skb->len > mtu && !skb_is_gso(skb)) {
 117                 return true; /* Packet size violate MTU size */
 118         }
 119         return false;
 120 }
 121 
 122 /* Get route to daddr, update *saddr, optionally bind route to saddr */
 123 static struct rtable *do_output_route4(struct net *net, __be32 daddr,
 124                                        int rt_mode, __be32 *saddr)
 125 {
 126         struct flowi4 fl4;
 127         struct rtable *rt;
 128         bool loop = false;
 129 
 130         memset(&fl4, 0, sizeof(fl4));
 131         fl4.daddr = daddr;
 132         fl4.flowi4_flags = (rt_mode & IP_VS_RT_MODE_KNOWN_NH) ?
 133                            FLOWI_FLAG_KNOWN_NH : 0;
 134 
 135 retry:
 136         rt = ip_route_output_key(net, &fl4);
 137         if (IS_ERR(rt)) {
 138                 /* Invalid saddr ? */
 139                 if (PTR_ERR(rt) == -EINVAL && *saddr &&
 140                     rt_mode & IP_VS_RT_MODE_CONNECT && !loop) {
 141                         *saddr = 0;
 142                         flowi4_update_output(&fl4, 0, 0, daddr, 0);
 143                         goto retry;
 144                 }
 145                 IP_VS_DBG_RL("ip_route_output error, dest: %pI4\n", &daddr);
 146                 return NULL;
 147         } else if (!*saddr && rt_mode & IP_VS_RT_MODE_CONNECT && fl4.saddr) {
 148                 ip_rt_put(rt);
 149                 *saddr = fl4.saddr;
 150                 flowi4_update_output(&fl4, 0, 0, daddr, fl4.saddr);
 151                 loop = true;
 152                 goto retry;
 153         }
 154         *saddr = fl4.saddr;
 155         return rt;
 156 }
 157 
 158 #ifdef CONFIG_IP_VS_IPV6
 159 static inline int __ip_vs_is_local_route6(struct rt6_info *rt)
 160 {
 161         return rt->dst.dev && rt->dst.dev->flags & IFF_LOOPBACK;
 162 }
 163 #endif
 164 
 165 static inline bool crosses_local_route_boundary(int skb_af, struct sk_buff *skb,
 166                                                 int rt_mode,
 167                                                 bool new_rt_is_local)
 168 {
 169         bool rt_mode_allow_local = !!(rt_mode & IP_VS_RT_MODE_LOCAL);
 170         bool rt_mode_allow_non_local = !!(rt_mode & IP_VS_RT_MODE_NON_LOCAL);
 171         bool rt_mode_allow_redirect = !!(rt_mode & IP_VS_RT_MODE_RDR);
 172         bool source_is_loopback;
 173         bool old_rt_is_local;
 174 
 175 #ifdef CONFIG_IP_VS_IPV6
 176         if (skb_af == AF_INET6) {
 177                 int addr_type = ipv6_addr_type(&ipv6_hdr(skb)->saddr);
 178 
 179                 source_is_loopback =
 180                         (!skb->dev || skb->dev->flags & IFF_LOOPBACK) &&
 181                         (addr_type & IPV6_ADDR_LOOPBACK);
 182                 old_rt_is_local = __ip_vs_is_local_route6(
 183                         (struct rt6_info *)skb_dst(skb));
 184         } else
 185 #endif
 186         {
 187                 source_is_loopback = ipv4_is_loopback(ip_hdr(skb)->saddr);
 188                 old_rt_is_local = skb_rtable(skb)->rt_flags & RTCF_LOCAL;
 189         }
 190 
 191         if (unlikely(new_rt_is_local)) {
 192                 if (!rt_mode_allow_local)
 193                         return true;
 194                 if (!rt_mode_allow_redirect && !old_rt_is_local)
 195                         return true;
 196         } else {
 197                 if (!rt_mode_allow_non_local)
 198                         return true;
 199                 if (source_is_loopback)
 200                         return true;
 201         }
 202         return false;
 203 }
 204 
 205 static inline void maybe_update_pmtu(int skb_af, struct sk_buff *skb, int mtu)
 206 {
 207         struct sock *sk = skb->sk;
 208         struct rtable *ort = skb_rtable(skb);
 209 
 210         if (!skb->dev && sk && sk_fullsock(sk))
 211                 ort->dst.ops->update_pmtu(&ort->dst, sk, NULL, mtu, true);
 212 }
 213 
 214 static inline bool ensure_mtu_is_adequate(struct netns_ipvs *ipvs, int skb_af,
 215                                           int rt_mode,
 216                                           struct ip_vs_iphdr *ipvsh,
 217                                           struct sk_buff *skb, int mtu)
 218 {
 219 #ifdef CONFIG_IP_VS_IPV6
 220         if (skb_af == AF_INET6) {
 221                 struct net *net = ipvs->net;
 222 
 223                 if (unlikely(__mtu_check_toobig_v6(skb, mtu))) {
 224                         if (!skb->dev)
 225                                 skb->dev = net->loopback_dev;
 226                         /* only send ICMP too big on first fragment */
 227                         if (!ipvsh->fragoffs && !ip_vs_iph_icmp(ipvsh))
 228                                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 229                         IP_VS_DBG(1, "frag needed for %pI6c\n",
 230                                   &ipv6_hdr(skb)->saddr);
 231                         return false;
 232                 }
 233         } else
 234 #endif
 235         {
 236                 /* If we're going to tunnel the packet and pmtu discovery
 237                  * is disabled, we'll just fragment it anyway
 238                  */
 239                 if ((rt_mode & IP_VS_RT_MODE_TUNNEL) && !sysctl_pmtu_disc(ipvs))
 240                         return true;
 241 
 242                 if (unlikely(ip_hdr(skb)->frag_off & htons(IP_DF) &&
 243                              skb->len > mtu && !skb_is_gso(skb) &&
 244                              !ip_vs_iph_icmp(ipvsh))) {
 245                         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
 246                                   htonl(mtu));
 247                         IP_VS_DBG(1, "frag needed for %pI4\n",
 248                                   &ip_hdr(skb)->saddr);
 249                         return false;
 250                 }
 251         }
 252 
 253         return true;
 254 }
 255 
 256 static inline bool decrement_ttl(struct netns_ipvs *ipvs,
 257                                  int skb_af,
 258                                  struct sk_buff *skb)
 259 {
 260         struct net *net = ipvs->net;
 261 
 262 #ifdef CONFIG_IP_VS_IPV6
 263         if (skb_af == AF_INET6) {
 264                 struct dst_entry *dst = skb_dst(skb);
 265 
 266                 /* check and decrement ttl */
 267                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 268                         struct inet6_dev *idev = __in6_dev_get_safely(skb->dev);
 269 
 270                         /* Force OUTPUT device used as source address */
 271                         skb->dev = dst->dev;
 272                         icmpv6_send(skb, ICMPV6_TIME_EXCEED,
 273                                     ICMPV6_EXC_HOPLIMIT, 0);
 274                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 275 
 276                         return false;
 277                 }
 278 
 279                 /* don't propagate ttl change to cloned packets */
 280                 if (skb_ensure_writable(skb, sizeof(struct ipv6hdr)))
 281                         return false;
 282 
 283                 ipv6_hdr(skb)->hop_limit--;
 284         } else
 285 #endif
 286         {
 287                 if (ip_hdr(skb)->ttl <= 1) {
 288                         /* Tell the sender its packet died... */
 289                         __IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS);
 290                         icmp_send(skb, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL, 0);
 291                         return false;
 292                 }
 293 
 294                 /* don't propagate ttl change to cloned packets */
 295                 if (skb_ensure_writable(skb, sizeof(struct iphdr)))
 296                         return false;
 297 
 298                 /* Decrease ttl */
 299                 ip_decrease_ttl(ip_hdr(skb));
 300         }
 301 
 302         return true;
 303 }
 304 
 305 /* Get route to destination or remote server */
 306 static int
 307 __ip_vs_get_out_rt(struct netns_ipvs *ipvs, int skb_af, struct sk_buff *skb,
 308                    struct ip_vs_dest *dest,
 309                    __be32 daddr, int rt_mode, __be32 *ret_saddr,
 310                    struct ip_vs_iphdr *ipvsh)
 311 {
 312         struct net *net = ipvs->net;
 313         struct ip_vs_dest_dst *dest_dst;
 314         struct rtable *rt;                      /* Route to the other host */
 315         int mtu;
 316         int local, noref = 1;
 317 
 318         if (dest) {
 319                 dest_dst = __ip_vs_dst_check(dest);
 320                 if (likely(dest_dst))
 321                         rt = (struct rtable *) dest_dst->dst_cache;
 322                 else {
 323                         dest_dst = ip_vs_dest_dst_alloc();
 324                         spin_lock_bh(&dest->dst_lock);
 325                         if (!dest_dst) {
 326                                 __ip_vs_dst_set(dest, NULL, NULL, 0);
 327                                 spin_unlock_bh(&dest->dst_lock);
 328                                 goto err_unreach;
 329                         }
 330                         rt = do_output_route4(net, dest->addr.ip, rt_mode,
 331                                               &dest_dst->dst_saddr.ip);
 332                         if (!rt) {
 333                                 __ip_vs_dst_set(dest, NULL, NULL, 0);
 334                                 spin_unlock_bh(&dest->dst_lock);
 335                                 ip_vs_dest_dst_free(dest_dst);
 336                                 goto err_unreach;
 337                         }
 338                         __ip_vs_dst_set(dest, dest_dst, &rt->dst, 0);
 339                         spin_unlock_bh(&dest->dst_lock);
 340                         IP_VS_DBG(10, "new dst %pI4, src %pI4, refcnt=%d\n",
 341                                   &dest->addr.ip, &dest_dst->dst_saddr.ip,
 342                                   atomic_read(&rt->dst.__refcnt));
 343                 }
 344                 if (ret_saddr)
 345                         *ret_saddr = dest_dst->dst_saddr.ip;
 346         } else {
 347                 __be32 saddr = htonl(INADDR_ANY);
 348 
 349                 noref = 0;
 350 
 351                 /* For such unconfigured boxes avoid many route lookups
 352                  * for performance reasons because we do not remember saddr
 353                  */
 354                 rt_mode &= ~IP_VS_RT_MODE_CONNECT;
 355                 rt = do_output_route4(net, daddr, rt_mode, &saddr);
 356                 if (!rt)
 357                         goto err_unreach;
 358                 if (ret_saddr)
 359                         *ret_saddr = saddr;
 360         }
 361 
 362         local = (rt->rt_flags & RTCF_LOCAL) ? 1 : 0;
 363         if (unlikely(crosses_local_route_boundary(skb_af, skb, rt_mode,
 364                                                   local))) {
 365                 IP_VS_DBG_RL("We are crossing local and non-local addresses"
 366                              " daddr=%pI4\n", &daddr);
 367                 goto err_put;
 368         }
 369 
 370         if (unlikely(local)) {
 371                 /* skb to local stack, preserve old route */
 372                 if (!noref)
 373                         ip_rt_put(rt);
 374                 return local;
 375         }
 376 
 377         if (!decrement_ttl(ipvs, skb_af, skb))
 378                 goto err_put;
 379 
 380         if (likely(!(rt_mode & IP_VS_RT_MODE_TUNNEL))) {
 381                 mtu = dst_mtu(&rt->dst);
 382         } else {
 383                 mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
 384                 if (!dest)
 385                         goto err_put;
 386                 if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
 387                         mtu -= sizeof(struct udphdr) + sizeof(struct guehdr);
 388                         if ((dest->tun_flags &
 389                              IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
 390                             skb->ip_summed == CHECKSUM_PARTIAL)
 391                                 mtu -= GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
 392                 } else if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GRE) {
 393                         __be16 tflags = 0;
 394 
 395                         if (dest->tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM)
 396                                 tflags |= TUNNEL_CSUM;
 397                         mtu -= gre_calc_hlen(tflags);
 398                 }
 399                 if (mtu < 68) {
 400                         IP_VS_DBG_RL("%s(): mtu less than 68\n", __func__);
 401                         goto err_put;
 402                 }
 403                 maybe_update_pmtu(skb_af, skb, mtu);
 404         }
 405 
 406         if (!ensure_mtu_is_adequate(ipvs, skb_af, rt_mode, ipvsh, skb, mtu))
 407                 goto err_put;
 408 
 409         skb_dst_drop(skb);
 410         if (noref) {
 411                 if (!local)
 412                         skb_dst_set_noref(skb, &rt->dst);
 413                 else
 414                         skb_dst_set(skb, dst_clone(&rt->dst));
 415         } else
 416                 skb_dst_set(skb, &rt->dst);
 417 
 418         return local;
 419 
 420 err_put:
 421         if (!noref)
 422                 ip_rt_put(rt);
 423         return -1;
 424 
 425 err_unreach:
 426         dst_link_failure(skb);
 427         return -1;
 428 }
 429 
 430 #ifdef CONFIG_IP_VS_IPV6
 431 static struct dst_entry *
 432 __ip_vs_route_output_v6(struct net *net, struct in6_addr *daddr,
 433                         struct in6_addr *ret_saddr, int do_xfrm, int rt_mode)
 434 {
 435         struct dst_entry *dst;
 436         struct flowi6 fl6 = {
 437                 .daddr = *daddr,
 438         };
 439 
 440         if (rt_mode & IP_VS_RT_MODE_KNOWN_NH)
 441                 fl6.flowi6_flags = FLOWI_FLAG_KNOWN_NH;
 442 
 443         dst = ip6_route_output(net, NULL, &fl6);
 444         if (dst->error)
 445                 goto out_err;
 446         if (!ret_saddr)
 447                 return dst;
 448         if (ipv6_addr_any(&fl6.saddr) &&
 449             ipv6_dev_get_saddr(net, ip6_dst_idev(dst)->dev,
 450                                &fl6.daddr, 0, &fl6.saddr) < 0)
 451                 goto out_err;
 452         if (do_xfrm) {
 453                 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
 454                 if (IS_ERR(dst)) {
 455                         dst = NULL;
 456                         goto out_err;
 457                 }
 458         }
 459         *ret_saddr = fl6.saddr;
 460         return dst;
 461 
 462 out_err:
 463         dst_release(dst);
 464         IP_VS_DBG_RL("ip6_route_output error, dest: %pI6\n", daddr);
 465         return NULL;
 466 }
 467 
 468 /*
 469  * Get route to destination or remote server
 470  */
 471 static int
 472 __ip_vs_get_out_rt_v6(struct netns_ipvs *ipvs, int skb_af, struct sk_buff *skb,
 473                       struct ip_vs_dest *dest,
 474                       struct in6_addr *daddr, struct in6_addr *ret_saddr,
 475                       struct ip_vs_iphdr *ipvsh, int do_xfrm, int rt_mode)
 476 {
 477         struct net *net = ipvs->net;
 478         struct ip_vs_dest_dst *dest_dst;
 479         struct rt6_info *rt;                    /* Route to the other host */
 480         struct dst_entry *dst;
 481         int mtu;
 482         int local, noref = 1;
 483 
 484         if (dest) {
 485                 dest_dst = __ip_vs_dst_check(dest);
 486                 if (likely(dest_dst))
 487                         rt = (struct rt6_info *) dest_dst->dst_cache;
 488                 else {
 489                         u32 cookie;
 490 
 491                         dest_dst = ip_vs_dest_dst_alloc();
 492                         spin_lock_bh(&dest->dst_lock);
 493                         if (!dest_dst) {
 494                                 __ip_vs_dst_set(dest, NULL, NULL, 0);
 495                                 spin_unlock_bh(&dest->dst_lock);
 496                                 goto err_unreach;
 497                         }
 498                         dst = __ip_vs_route_output_v6(net, &dest->addr.in6,
 499                                                       &dest_dst->dst_saddr.in6,
 500                                                       do_xfrm, rt_mode);
 501                         if (!dst) {
 502                                 __ip_vs_dst_set(dest, NULL, NULL, 0);
 503                                 spin_unlock_bh(&dest->dst_lock);
 504                                 ip_vs_dest_dst_free(dest_dst);
 505                                 goto err_unreach;
 506                         }
 507                         rt = (struct rt6_info *) dst;
 508                         cookie = rt6_get_cookie(rt);
 509                         __ip_vs_dst_set(dest, dest_dst, &rt->dst, cookie);
 510                         spin_unlock_bh(&dest->dst_lock);
 511                         IP_VS_DBG(10, "new dst %pI6, src %pI6, refcnt=%d\n",
 512                                   &dest->addr.in6, &dest_dst->dst_saddr.in6,
 513                                   atomic_read(&rt->dst.__refcnt));
 514                 }
 515                 if (ret_saddr)
 516                         *ret_saddr = dest_dst->dst_saddr.in6;
 517         } else {
 518                 noref = 0;
 519                 dst = __ip_vs_route_output_v6(net, daddr, ret_saddr, do_xfrm,
 520                                               rt_mode);
 521                 if (!dst)
 522                         goto err_unreach;
 523                 rt = (struct rt6_info *) dst;
 524         }
 525 
 526         local = __ip_vs_is_local_route6(rt);
 527 
 528         if (unlikely(crosses_local_route_boundary(skb_af, skb, rt_mode,
 529                                                   local))) {
 530                 IP_VS_DBG_RL("We are crossing local and non-local addresses"
 531                              " daddr=%pI6\n", daddr);
 532                 goto err_put;
 533         }
 534 
 535         if (unlikely(local)) {
 536                 /* skb to local stack, preserve old route */
 537                 if (!noref)
 538                         dst_release(&rt->dst);
 539                 return local;
 540         }
 541 
 542         if (!decrement_ttl(ipvs, skb_af, skb))
 543                 goto err_put;
 544 
 545         /* MTU checking */
 546         if (likely(!(rt_mode & IP_VS_RT_MODE_TUNNEL)))
 547                 mtu = dst_mtu(&rt->dst);
 548         else {
 549                 mtu = dst_mtu(&rt->dst) - sizeof(struct ipv6hdr);
 550                 if (!dest)
 551                         goto err_put;
 552                 if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
 553                         mtu -= sizeof(struct udphdr) + sizeof(struct guehdr);
 554                         if ((dest->tun_flags &
 555                              IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
 556                             skb->ip_summed == CHECKSUM_PARTIAL)
 557                                 mtu -= GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
 558                 } else if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GRE) {
 559                         __be16 tflags = 0;
 560 
 561                         if (dest->tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM)
 562                                 tflags |= TUNNEL_CSUM;
 563                         mtu -= gre_calc_hlen(tflags);
 564                 }
 565                 if (mtu < IPV6_MIN_MTU) {
 566                         IP_VS_DBG_RL("%s(): mtu less than %d\n", __func__,
 567                                      IPV6_MIN_MTU);
 568                         goto err_put;
 569                 }
 570                 maybe_update_pmtu(skb_af, skb, mtu);
 571         }
 572 
 573         if (!ensure_mtu_is_adequate(ipvs, skb_af, rt_mode, ipvsh, skb, mtu))
 574                 goto err_put;
 575 
 576         skb_dst_drop(skb);
 577         if (noref) {
 578                 if (!local)
 579                         skb_dst_set_noref(skb, &rt->dst);
 580                 else
 581                         skb_dst_set(skb, dst_clone(&rt->dst));
 582         } else
 583                 skb_dst_set(skb, &rt->dst);
 584 
 585         return local;
 586 
 587 err_put:
 588         if (!noref)
 589                 dst_release(&rt->dst);
 590         return -1;
 591 
 592 err_unreach:
 593         /* The ip6_link_failure function requires the dev field to be set
 594          * in order to get the net (further for the sake of fwmark
 595          * reflection).
 596          */
 597         if (!skb->dev)
 598                 skb->dev = skb_dst(skb)->dev;
 599 
 600         dst_link_failure(skb);
 601         return -1;
 602 }
 603 #endif
 604 
 605 
 606 /* return NF_ACCEPT to allow forwarding or other NF_xxx on error */
 607 static inline int ip_vs_tunnel_xmit_prepare(struct sk_buff *skb,
 608                                             struct ip_vs_conn *cp)
 609 {
 610         int ret = NF_ACCEPT;
 611 
 612         skb->ipvs_property = 1;
 613         if (unlikely(cp->flags & IP_VS_CONN_F_NFCT))
 614                 ret = ip_vs_confirm_conntrack(skb);
 615         if (ret == NF_ACCEPT) {
 616                 nf_reset_ct(skb);
 617                 skb_forward_csum(skb);
 618         }
 619         return ret;
 620 }
 621 
 622 /* In the event of a remote destination, it's possible that we would have
 623  * matches against an old socket (particularly a TIME-WAIT socket). This
 624  * causes havoc down the line (ip_local_out et. al. expect regular sockets
 625  * and invalid memory accesses will happen) so simply drop the association
 626  * in this case.
 627 */
 628 static inline void ip_vs_drop_early_demux_sk(struct sk_buff *skb)
 629 {
 630         /* If dev is set, the packet came from the LOCAL_IN callback and
 631          * not from a local TCP socket.
 632          */
 633         if (skb->dev)
 634                 skb_orphan(skb);
 635 }
 636 
 637 /* return NF_STOLEN (sent) or NF_ACCEPT if local=1 (not sent) */
 638 static inline int ip_vs_nat_send_or_cont(int pf, struct sk_buff *skb,
 639                                          struct ip_vs_conn *cp, int local)
 640 {
 641         int ret = NF_STOLEN;
 642 
 643         skb->ipvs_property = 1;
 644         if (likely(!(cp->flags & IP_VS_CONN_F_NFCT)))
 645                 ip_vs_notrack(skb);
 646         else
 647                 ip_vs_update_conntrack(skb, cp, 1);
 648 
 649         /* Remove the early_demux association unless it's bound for the
 650          * exact same port and address on this host after translation.
 651          */
 652         if (!local || cp->vport != cp->dport ||
 653             !ip_vs_addr_equal(cp->af, &cp->vaddr, &cp->daddr))
 654                 ip_vs_drop_early_demux_sk(skb);
 655 
 656         if (!local) {
 657                 skb_forward_csum(skb);
 658                 NF_HOOK(pf, NF_INET_LOCAL_OUT, cp->ipvs->net, NULL, skb,
 659                         NULL, skb_dst(skb)->dev, dst_output);
 660         } else
 661                 ret = NF_ACCEPT;
 662 
 663         return ret;
 664 }
 665 
 666 /* return NF_STOLEN (sent) or NF_ACCEPT if local=1 (not sent) */
 667 static inline int ip_vs_send_or_cont(int pf, struct sk_buff *skb,
 668                                      struct ip_vs_conn *cp, int local)
 669 {
 670         int ret = NF_STOLEN;
 671 
 672         skb->ipvs_property = 1;
 673         if (likely(!(cp->flags & IP_VS_CONN_F_NFCT)))
 674                 ip_vs_notrack(skb);
 675         if (!local) {
 676                 ip_vs_drop_early_demux_sk(skb);
 677                 skb_forward_csum(skb);
 678                 NF_HOOK(pf, NF_INET_LOCAL_OUT, cp->ipvs->net, NULL, skb,
 679                         NULL, skb_dst(skb)->dev, dst_output);
 680         } else
 681                 ret = NF_ACCEPT;
 682         return ret;
 683 }
 684 
 685 
 686 /*
 687  *      NULL transmitter (do nothing except return NF_ACCEPT)
 688  */
 689 int
 690 ip_vs_null_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 691                 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
 692 {
 693         /* we do not touch skb and do not need pskb ptr */
 694         return ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 1);
 695 }
 696 
 697 
 698 /*
 699  *      Bypass transmitter
 700  *      Let packets bypass the destination when the destination is not
 701  *      available, it may be only used in transparent cache cluster.
 702  */
 703 int
 704 ip_vs_bypass_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 705                   struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
 706 {
 707         struct iphdr  *iph = ip_hdr(skb);
 708 
 709         EnterFunction(10);
 710 
 711         if (__ip_vs_get_out_rt(cp->ipvs, cp->af, skb, NULL, iph->daddr,
 712                                IP_VS_RT_MODE_NON_LOCAL, NULL, ipvsh) < 0)
 713                 goto tx_error;
 714 
 715         ip_send_check(iph);
 716 
 717         /* Another hack: avoid icmp_send in ip_fragment */
 718         skb->ignore_df = 1;
 719 
 720         ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 0);
 721 
 722         LeaveFunction(10);
 723         return NF_STOLEN;
 724 
 725  tx_error:
 726         kfree_skb(skb);
 727         LeaveFunction(10);
 728         return NF_STOLEN;
 729 }
 730 
 731 #ifdef CONFIG_IP_VS_IPV6
 732 int
 733 ip_vs_bypass_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
 734                      struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
 735 {
 736         struct ipv6hdr *iph = ipv6_hdr(skb);
 737 
 738         EnterFunction(10);
 739 
 740         if (__ip_vs_get_out_rt_v6(cp->ipvs, cp->af, skb, NULL,
 741                                   &iph->daddr, NULL,
 742                                   ipvsh, 0, IP_VS_RT_MODE_NON_LOCAL) < 0)
 743                 goto tx_error;
 744 
 745         /* Another hack: avoid icmp_send in ip_fragment */
 746         skb->ignore_df = 1;
 747 
 748         ip_vs_send_or_cont(NFPROTO_IPV6, skb, cp, 0);
 749 
 750         LeaveFunction(10);
 751         return NF_STOLEN;
 752 
 753  tx_error:
 754         kfree_skb(skb);
 755         LeaveFunction(10);
 756         return NF_STOLEN;
 757 }
 758 #endif
 759 
 760 /*
 761  *      NAT transmitter (only for outside-to-inside nat forwarding)
 762  *      Not used for related ICMP
 763  */
 764 int
 765 ip_vs_nat_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 766                struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
 767 {
 768         struct rtable *rt;              /* Route to the other host */
 769         int local, rc, was_input;
 770 
 771         EnterFunction(10);
 772 
 773         /* check if it is a connection of no-client-port */
 774         if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT)) {
 775                 __be16 _pt, *p;
 776 
 777                 p = skb_header_pointer(skb, ipvsh->len, sizeof(_pt), &_pt);
 778                 if (p == NULL)
 779                         goto tx_error;
 780                 ip_vs_conn_fill_cport(cp, *p);
 781                 IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
 782         }
 783 
 784         was_input = rt_is_input_route(skb_rtable(skb));
 785         local = __ip_vs_get_out_rt(cp->ipvs, cp->af, skb, cp->dest, cp->daddr.ip,
 786                                    IP_VS_RT_MODE_LOCAL |
 787                                    IP_VS_RT_MODE_NON_LOCAL |
 788                                    IP_VS_RT_MODE_RDR, NULL, ipvsh);
 789         if (local < 0)
 790                 goto tx_error;
 791         rt = skb_rtable(skb);
 792         /*
 793          * Avoid duplicate tuple in reply direction for NAT traffic
 794          * to local address when connection is sync-ed
 795          */
 796 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 797         if (cp->flags & IP_VS_CONN_F_SYNC && local) {
 798                 enum ip_conntrack_info ctinfo;
 799                 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
 800 
 801                 if (ct) {
 802                         IP_VS_DBG_RL_PKT(10, AF_INET, pp, skb, ipvsh->off,
 803                                          "ip_vs_nat_xmit(): "
 804                                          "stopping DNAT to local address");
 805                         goto tx_error;
 806                 }
 807         }
 808 #endif
 809 
 810         /* From world but DNAT to loopback address? */
 811         if (local && ipv4_is_loopback(cp->daddr.ip) && was_input) {
 812                 IP_VS_DBG_RL_PKT(1, AF_INET, pp, skb, ipvsh->off,
 813                                  "ip_vs_nat_xmit(): stopping DNAT to loopback "
 814                                  "address");
 815                 goto tx_error;
 816         }
 817 
 818         /* copy-on-write the packet before mangling it */
 819         if (skb_ensure_writable(skb, sizeof(struct iphdr)))
 820                 goto tx_error;
 821 
 822         if (skb_cow(skb, rt->dst.dev->hard_header_len))
 823                 goto tx_error;
 824 
 825         /* mangle the packet */
 826         if (pp->dnat_handler && !pp->dnat_handler(skb, pp, cp, ipvsh))
 827                 goto tx_error;
 828         ip_hdr(skb)->daddr = cp->daddr.ip;
 829         ip_send_check(ip_hdr(skb));
 830 
 831         IP_VS_DBG_PKT(10, AF_INET, pp, skb, ipvsh->off, "After DNAT");
 832 
 833         /* FIXME: when application helper enlarges the packet and the length
 834            is larger than the MTU of outgoing device, there will be still
 835            MTU problem. */
 836 
 837         /* Another hack: avoid icmp_send in ip_fragment */
 838         skb->ignore_df = 1;
 839 
 840         rc = ip_vs_nat_send_or_cont(NFPROTO_IPV4, skb, cp, local);
 841 
 842         LeaveFunction(10);
 843         return rc;
 844 
 845   tx_error:
 846         kfree_skb(skb);
 847         LeaveFunction(10);
 848         return NF_STOLEN;
 849 }
 850 
 851 #ifdef CONFIG_IP_VS_IPV6
 852 int
 853 ip_vs_nat_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
 854                   struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
 855 {
 856         struct rt6_info *rt;            /* Route to the other host */
 857         int local, rc;
 858 
 859         EnterFunction(10);
 860 
 861         /* check if it is a connection of no-client-port */
 862         if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT && !ipvsh->fragoffs)) {
 863                 __be16 _pt, *p;
 864                 p = skb_header_pointer(skb, ipvsh->len, sizeof(_pt), &_pt);
 865                 if (p == NULL)
 866                         goto tx_error;
 867                 ip_vs_conn_fill_cport(cp, *p);
 868                 IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
 869         }
 870 
 871         local = __ip_vs_get_out_rt_v6(cp->ipvs, cp->af, skb, cp->dest,
 872                                       &cp->daddr.in6,
 873                                       NULL, ipvsh, 0,
 874                                       IP_VS_RT_MODE_LOCAL |
 875                                       IP_VS_RT_MODE_NON_LOCAL |
 876                                       IP_VS_RT_MODE_RDR);
 877         if (local < 0)
 878                 goto tx_error;
 879         rt = (struct rt6_info *) skb_dst(skb);
 880         /*
 881          * Avoid duplicate tuple in reply direction for NAT traffic
 882          * to local address when connection is sync-ed
 883          */
 884 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 885         if (cp->flags & IP_VS_CONN_F_SYNC && local) {
 886                 enum ip_conntrack_info ctinfo;
 887                 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
 888 
 889                 if (ct) {
 890                         IP_VS_DBG_RL_PKT(10, AF_INET6, pp, skb, ipvsh->off,
 891                                          "ip_vs_nat_xmit_v6(): "
 892                                          "stopping DNAT to local address");
 893                         goto tx_error;
 894                 }
 895         }
 896 #endif
 897 
 898         /* From world but DNAT to loopback address? */
 899         if (local && skb->dev && !(skb->dev->flags & IFF_LOOPBACK) &&
 900             ipv6_addr_type(&cp->daddr.in6) & IPV6_ADDR_LOOPBACK) {
 901                 IP_VS_DBG_RL_PKT(1, AF_INET6, pp, skb, ipvsh->off,
 902                                  "ip_vs_nat_xmit_v6(): "
 903                                  "stopping DNAT to loopback address");
 904                 goto tx_error;
 905         }
 906 
 907         /* copy-on-write the packet before mangling it */
 908         if (skb_ensure_writable(skb, sizeof(struct ipv6hdr)))
 909                 goto tx_error;
 910 
 911         if (skb_cow(skb, rt->dst.dev->hard_header_len))
 912                 goto tx_error;
 913 
 914         /* mangle the packet */
 915         if (pp->dnat_handler && !pp->dnat_handler(skb, pp, cp, ipvsh))
 916                 goto tx_error;
 917         ipv6_hdr(skb)->daddr = cp->daddr.in6;
 918 
 919         IP_VS_DBG_PKT(10, AF_INET6, pp, skb, ipvsh->off, "After DNAT");
 920 
 921         /* FIXME: when application helper enlarges the packet and the length
 922            is larger than the MTU of outgoing device, there will be still
 923            MTU problem. */
 924 
 925         /* Another hack: avoid icmp_send in ip_fragment */
 926         skb->ignore_df = 1;
 927 
 928         rc = ip_vs_nat_send_or_cont(NFPROTO_IPV6, skb, cp, local);
 929 
 930         LeaveFunction(10);
 931         return rc;
 932 
 933 tx_error:
 934         LeaveFunction(10);
 935         kfree_skb(skb);
 936         return NF_STOLEN;
 937 }
 938 #endif
 939 
 940 /* When forwarding a packet, we must ensure that we've got enough headroom
 941  * for the encapsulation packet in the skb.  This also gives us an
 942  * opportunity to figure out what the payload_len, dsfield, ttl, and df
 943  * values should be, so that we won't need to look at the old ip header
 944  * again
 945  */
 946 static struct sk_buff *
 947 ip_vs_prepare_tunneled_skb(struct sk_buff *skb, int skb_af,
 948                            unsigned int max_headroom, __u8 *next_protocol,
 949                            __u32 *payload_len, __u8 *dsfield, __u8 *ttl,
 950                            __be16 *df)
 951 {
 952         struct sk_buff *new_skb = NULL;
 953         struct iphdr *old_iph = NULL;
 954         __u8 old_dsfield;
 955 #ifdef CONFIG_IP_VS_IPV6
 956         struct ipv6hdr *old_ipv6h = NULL;
 957 #endif
 958 
 959         ip_vs_drop_early_demux_sk(skb);
 960 
 961         if (skb_headroom(skb) < max_headroom || skb_cloned(skb)) {
 962                 new_skb = skb_realloc_headroom(skb, max_headroom);
 963                 if (!new_skb)
 964                         goto error;
 965                 if (skb->sk)
 966                         skb_set_owner_w(new_skb, skb->sk);
 967                 consume_skb(skb);
 968                 skb = new_skb;
 969         }
 970 
 971 #ifdef CONFIG_IP_VS_IPV6
 972         if (skb_af == AF_INET6) {
 973                 old_ipv6h = ipv6_hdr(skb);
 974                 *next_protocol = IPPROTO_IPV6;
 975                 if (payload_len)
 976                         *payload_len =
 977                                 ntohs(old_ipv6h->payload_len) +
 978                                 sizeof(*old_ipv6h);
 979                 old_dsfield = ipv6_get_dsfield(old_ipv6h);
 980                 *ttl = old_ipv6h->hop_limit;
 981                 if (df)
 982                         *df = 0;
 983         } else
 984 #endif
 985         {
 986                 old_iph = ip_hdr(skb);
 987                 /* Copy DF, reset fragment offset and MF */
 988                 if (df)
 989                         *df = (old_iph->frag_off & htons(IP_DF));
 990                 *next_protocol = IPPROTO_IPIP;
 991 
 992                 /* fix old IP header checksum */
 993                 ip_send_check(old_iph);
 994                 old_dsfield = ipv4_get_dsfield(old_iph);
 995                 *ttl = old_iph->ttl;
 996                 if (payload_len)
 997                         *payload_len = ntohs(old_iph->tot_len);
 998         }
 999 
1000         /* Implement full-functionality option for ECN encapsulation */
1001         *dsfield = INET_ECN_encapsulate(old_dsfield, old_dsfield);
1002 
1003         return skb;
1004 error:
1005         kfree_skb(skb);
1006         return ERR_PTR(-ENOMEM);
1007 }
1008 
1009 static inline int __tun_gso_type_mask(int encaps_af, int orig_af)
1010 {
1011         switch (encaps_af) {
1012         case AF_INET:
1013                 return SKB_GSO_IPXIP4;
1014         case AF_INET6:
1015                 return SKB_GSO_IPXIP6;
1016         default:
1017                 return 0;
1018         }
1019 }
1020 
1021 static int
1022 ipvs_gue_encap(struct net *net, struct sk_buff *skb,
1023                struct ip_vs_conn *cp, __u8 *next_protocol)
1024 {
1025         __be16 dport;
1026         __be16 sport = udp_flow_src_port(net, skb, 0, 0, false);
1027         struct udphdr  *udph;   /* Our new UDP header */
1028         struct guehdr  *gueh;   /* Our new GUE header */
1029         size_t hdrlen, optlen = 0;
1030         void *data;
1031         bool need_priv = false;
1032 
1033         if ((cp->dest->tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
1034             skb->ip_summed == CHECKSUM_PARTIAL) {
1035                 optlen += GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
1036                 need_priv = true;
1037         }
1038 
1039         hdrlen = sizeof(struct guehdr) + optlen;
1040 
1041         skb_push(skb, hdrlen);
1042 
1043         gueh = (struct guehdr *)skb->data;
1044 
1045         gueh->control = 0;
1046         gueh->version = 0;
1047         gueh->hlen = optlen >> 2;
1048         gueh->flags = 0;
1049         gueh->proto_ctype = *next_protocol;
1050 
1051         data = &gueh[1];
1052 
1053         if (need_priv) {
1054                 __be32 *flags = data;
1055                 u16 csum_start = skb_checksum_start_offset(skb);
1056                 __be16 *pd;
1057 
1058                 gueh->flags |= GUE_FLAG_PRIV;
1059                 *flags = 0;
1060                 data += GUE_LEN_PRIV;
1061 
1062                 if (csum_start < hdrlen)
1063                         return -EINVAL;
1064 
1065                 csum_start -= hdrlen;
1066                 pd = data;
1067                 pd[0] = htons(csum_start);
1068                 pd[1] = htons(csum_start + skb->csum_offset);
1069 
1070                 if (!skb_is_gso(skb)) {
1071                         skb->ip_summed = CHECKSUM_NONE;
1072                         skb->encapsulation = 0;
1073                 }
1074 
1075                 *flags |= GUE_PFLAG_REMCSUM;
1076                 data += GUE_PLEN_REMCSUM;
1077         }
1078 
1079         skb_push(skb, sizeof(struct udphdr));
1080         skb_reset_transport_header(skb);
1081 
1082         udph = udp_hdr(skb);
1083 
1084         dport = cp->dest->tun_port;
1085         udph->dest = dport;
1086         udph->source = sport;
1087         udph->len = htons(skb->len);
1088         udph->check = 0;
1089 
1090         *next_protocol = IPPROTO_UDP;
1091 
1092         return 0;
1093 }
1094 
1095 static void
1096 ipvs_gre_encap(struct net *net, struct sk_buff *skb,
1097                struct ip_vs_conn *cp, __u8 *next_protocol)
1098 {
1099         __be16 proto = *next_protocol == IPPROTO_IPIP ?
1100                                 htons(ETH_P_IP) : htons(ETH_P_IPV6);
1101         __be16 tflags = 0;
1102         size_t hdrlen;
1103 
1104         if (cp->dest->tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM)
1105                 tflags |= TUNNEL_CSUM;
1106 
1107         hdrlen = gre_calc_hlen(tflags);
1108         gre_build_header(skb, hdrlen, tflags, proto, 0, 0);
1109 
1110         *next_protocol = IPPROTO_GRE;
1111 }
1112 
1113 /*
1114  *   IP Tunneling transmitter
1115  *
1116  *   This function encapsulates the packet in a new IP packet, its
1117  *   destination will be set to cp->daddr. Most code of this function
1118  *   is taken from ipip.c.
1119  *
1120  *   It is used in VS/TUN cluster. The load balancer selects a real
1121  *   server from a cluster based on a scheduling algorithm,
1122  *   encapsulates the request packet and forwards it to the selected
1123  *   server. For example, all real servers are configured with
1124  *   "ifconfig tunl0 <Virtual IP Address> up". When the server receives
1125  *   the encapsulated packet, it will decapsulate the packet, processe
1126  *   the request and return the response packets directly to the client
1127  *   without passing the load balancer. This can greatly increase the
1128  *   scalability of virtual server.
1129  *
1130  *   Used for ANY protocol
1131  */
1132 int
1133 ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
1134                   struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
1135 {
1136         struct netns_ipvs *ipvs = cp->ipvs;
1137         struct net *net = ipvs->net;
1138         struct rtable *rt;                      /* Route to the other host */
1139         __be32 saddr;                           /* Source for tunnel */
1140         struct net_device *tdev;                /* Device to other host */
1141         __u8 next_protocol = 0;
1142         __u8 dsfield = 0;
1143         __u8 ttl = 0;
1144         __be16 df = 0;
1145         __be16 *dfp = NULL;
1146         struct iphdr  *iph;                     /* Our new IP header */
1147         unsigned int max_headroom;              /* The extra header space needed */
1148         int ret, local;
1149         int tun_type, gso_type;
1150         int tun_flags;
1151 
1152         EnterFunction(10);
1153 
1154         local = __ip_vs_get_out_rt(ipvs, cp->af, skb, cp->dest, cp->daddr.ip,
1155                                    IP_VS_RT_MODE_LOCAL |
1156                                    IP_VS_RT_MODE_NON_LOCAL |
1157                                    IP_VS_RT_MODE_CONNECT |
1158                                    IP_VS_RT_MODE_TUNNEL, &saddr, ipvsh);
1159         if (local < 0)
1160                 goto tx_error;
1161         if (local)
1162                 return ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 1);
1163 
1164         rt = skb_rtable(skb);
1165         tdev = rt->dst.dev;
1166 
1167         /*
1168          * Okay, now see if we can stuff it in the buffer as-is.
1169          */
1170         max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct iphdr);
1171 
1172         tun_type = cp->dest->tun_type;
1173         tun_flags = cp->dest->tun_flags;
1174 
1175         if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
1176                 size_t gue_hdrlen, gue_optlen = 0;
1177 
1178                 if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
1179                     skb->ip_summed == CHECKSUM_PARTIAL) {
1180                         gue_optlen += GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
1181                 }
1182                 gue_hdrlen = sizeof(struct guehdr) + gue_optlen;
1183 
1184                 max_headroom += sizeof(struct udphdr) + gue_hdrlen;
1185         } else if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GRE) {
1186                 size_t gre_hdrlen;
1187                 __be16 tflags = 0;
1188 
1189                 if (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM)
1190                         tflags |= TUNNEL_CSUM;
1191                 gre_hdrlen = gre_calc_hlen(tflags);
1192 
1193                 max_headroom += gre_hdrlen;
1194         }
1195 
1196         /* We only care about the df field if sysctl_pmtu_disc(ipvs) is set */
1197         dfp = sysctl_pmtu_disc(ipvs) ? &df : NULL;
1198         skb = ip_vs_prepare_tunneled_skb(skb, cp->af, max_headroom,
1199                                          &next_protocol, NULL, &dsfield,
1200                                          &ttl, dfp);
1201         if (IS_ERR(skb))
1202                 goto tx_error;
1203 
1204         gso_type = __tun_gso_type_mask(AF_INET, cp->af);
1205         if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
1206                 if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM) ||
1207                     (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM))
1208                         gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
1209                 else
1210                         gso_type |= SKB_GSO_UDP_TUNNEL;
1211                 if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
1212                     skb->ip_summed == CHECKSUM_PARTIAL) {
1213                         gso_type |= SKB_GSO_TUNNEL_REMCSUM;
1214                 }
1215         } else if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GRE) {
1216                 if (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM)
1217                         gso_type |= SKB_GSO_GRE_CSUM;
1218                 else
1219                         gso_type |= SKB_GSO_GRE;
1220         }
1221 
1222         if (iptunnel_handle_offloads(skb, gso_type))
1223                 goto tx_error;
1224 
1225         skb->transport_header = skb->network_header;
1226 
1227         skb_set_inner_ipproto(skb, next_protocol);
1228 
1229         if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
1230                 bool check = false;
1231 
1232                 if (ipvs_gue_encap(net, skb, cp, &next_protocol))
1233                         goto tx_error;
1234 
1235                 if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM) ||
1236                     (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM))
1237                         check = true;
1238 
1239                 udp_set_csum(!check, skb, saddr, cp->daddr.ip, skb->len);
1240         } else if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GRE)
1241                 ipvs_gre_encap(net, skb, cp, &next_protocol);
1242 
1243         skb_push(skb, sizeof(struct iphdr));
1244         skb_reset_network_header(skb);
1245         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1246 
1247         /*
1248          *      Push down and install the IPIP header.
1249          */
1250         iph                     =       ip_hdr(skb);
1251         iph->version            =       4;
1252         iph->ihl                =       sizeof(struct iphdr)>>2;
1253         iph->frag_off           =       df;
1254         iph->protocol           =       next_protocol;
1255         iph->tos                =       dsfield;
1256         iph->daddr              =       cp->daddr.ip;
1257         iph->saddr              =       saddr;
1258         iph->ttl                =       ttl;
1259         ip_select_ident(net, skb, NULL);
1260 
1261         /* Another hack: avoid icmp_send in ip_fragment */
1262         skb->ignore_df = 1;
1263 
1264         ret = ip_vs_tunnel_xmit_prepare(skb, cp);
1265         if (ret == NF_ACCEPT)
1266                 ip_local_out(net, skb->sk, skb);
1267         else if (ret == NF_DROP)
1268                 kfree_skb(skb);
1269 
1270         LeaveFunction(10);
1271 
1272         return NF_STOLEN;
1273 
1274   tx_error:
1275         if (!IS_ERR(skb))
1276                 kfree_skb(skb);
1277         LeaveFunction(10);
1278         return NF_STOLEN;
1279 }
1280 
1281 #ifdef CONFIG_IP_VS_IPV6
1282 int
1283 ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
1284                      struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
1285 {
1286         struct netns_ipvs *ipvs = cp->ipvs;
1287         struct net *net = ipvs->net;
1288         struct rt6_info *rt;            /* Route to the other host */
1289         struct in6_addr saddr;          /* Source for tunnel */
1290         struct net_device *tdev;        /* Device to other host */
1291         __u8 next_protocol = 0;
1292         __u32 payload_len = 0;
1293         __u8 dsfield = 0;
1294         __u8 ttl = 0;
1295         struct ipv6hdr  *iph;           /* Our new IP header */
1296         unsigned int max_headroom;      /* The extra header space needed */
1297         int ret, local;
1298         int tun_type, gso_type;
1299         int tun_flags;
1300 
1301         EnterFunction(10);
1302 
1303         local = __ip_vs_get_out_rt_v6(ipvs, cp->af, skb, cp->dest,
1304                                       &cp->daddr.in6,
1305                                       &saddr, ipvsh, 1,
1306                                       IP_VS_RT_MODE_LOCAL |
1307                                       IP_VS_RT_MODE_NON_LOCAL |
1308                                       IP_VS_RT_MODE_TUNNEL);
1309         if (local < 0)
1310                 goto tx_error;
1311         if (local)
1312                 return ip_vs_send_or_cont(NFPROTO_IPV6, skb, cp, 1);
1313 
1314         rt = (struct rt6_info *) skb_dst(skb);
1315         tdev = rt->dst.dev;
1316 
1317         /*
1318          * Okay, now see if we can stuff it in the buffer as-is.
1319          */
1320         max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct ipv6hdr);
1321 
1322         tun_type = cp->dest->tun_type;
1323         tun_flags = cp->dest->tun_flags;
1324 
1325         if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
1326                 size_t gue_hdrlen, gue_optlen = 0;
1327 
1328                 if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
1329                     skb->ip_summed == CHECKSUM_PARTIAL) {
1330                         gue_optlen += GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
1331                 }
1332                 gue_hdrlen = sizeof(struct guehdr) + gue_optlen;
1333 
1334                 max_headroom += sizeof(struct udphdr) + gue_hdrlen;
1335         } else if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GRE) {
1336                 size_t gre_hdrlen;
1337                 __be16 tflags = 0;
1338 
1339                 if (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM)
1340                         tflags |= TUNNEL_CSUM;
1341                 gre_hdrlen = gre_calc_hlen(tflags);
1342 
1343                 max_headroom += gre_hdrlen;
1344         }
1345 
1346         skb = ip_vs_prepare_tunneled_skb(skb, cp->af, max_headroom,
1347                                          &next_protocol, &payload_len,
1348                                          &dsfield, &ttl, NULL);
1349         if (IS_ERR(skb))
1350                 goto tx_error;
1351 
1352         gso_type = __tun_gso_type_mask(AF_INET6, cp->af);
1353         if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
1354                 if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM) ||
1355                     (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM))
1356                         gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
1357                 else
1358                         gso_type |= SKB_GSO_UDP_TUNNEL;
1359                 if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
1360                     skb->ip_summed == CHECKSUM_PARTIAL) {
1361                         gso_type |= SKB_GSO_TUNNEL_REMCSUM;
1362                 }
1363         } else if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GRE) {
1364                 if (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM)
1365                         gso_type |= SKB_GSO_GRE_CSUM;
1366                 else
1367                         gso_type |= SKB_GSO_GRE;
1368         }
1369 
1370         if (iptunnel_handle_offloads(skb, gso_type))
1371                 goto tx_error;
1372 
1373         skb->transport_header = skb->network_header;
1374 
1375         skb_set_inner_ipproto(skb, next_protocol);
1376 
1377         if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
1378                 bool check = false;
1379 
1380                 if (ipvs_gue_encap(net, skb, cp, &next_protocol))
1381                         goto tx_error;
1382 
1383                 if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM) ||
1384                     (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM))
1385                         check = true;
1386 
1387                 udp6_set_csum(!check, skb, &saddr, &cp->daddr.in6, skb->len);
1388         } else if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GRE)
1389                 ipvs_gre_encap(net, skb, cp, &next_protocol);
1390 
1391         skb_push(skb, sizeof(struct ipv6hdr));
1392         skb_reset_network_header(skb);
1393         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1394 
1395         /*
1396          *      Push down and install the IPIP header.
1397          */
1398         iph                     =       ipv6_hdr(skb);
1399         iph->version            =       6;
1400         iph->nexthdr            =       next_protocol;
1401         iph->payload_len        =       htons(payload_len);
1402         memset(&iph->flow_lbl, 0, sizeof(iph->flow_lbl));
1403         ipv6_change_dsfield(iph, 0, dsfield);
1404         iph->daddr = cp->daddr.in6;
1405         iph->saddr = saddr;
1406         iph->hop_limit          =       ttl;
1407 
1408         /* Another hack: avoid icmp_send in ip_fragment */
1409         skb->ignore_df = 1;
1410 
1411         ret = ip_vs_tunnel_xmit_prepare(skb, cp);
1412         if (ret == NF_ACCEPT)
1413                 ip6_local_out(net, skb->sk, skb);
1414         else if (ret == NF_DROP)
1415                 kfree_skb(skb);
1416 
1417         LeaveFunction(10);
1418 
1419         return NF_STOLEN;
1420 
1421 tx_error:
1422         if (!IS_ERR(skb))
1423                 kfree_skb(skb);
1424         LeaveFunction(10);
1425         return NF_STOLEN;
1426 }
1427 #endif
1428 
1429 
1430 /*
1431  *      Direct Routing transmitter
1432  *      Used for ANY protocol
1433  */
1434 int
1435 ip_vs_dr_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
1436               struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
1437 {
1438         int local;
1439 
1440         EnterFunction(10);
1441 
1442         local = __ip_vs_get_out_rt(cp->ipvs, cp->af, skb, cp->dest, cp->daddr.ip,
1443                                    IP_VS_RT_MODE_LOCAL |
1444                                    IP_VS_RT_MODE_NON_LOCAL |
1445                                    IP_VS_RT_MODE_KNOWN_NH, NULL, ipvsh);
1446         if (local < 0)
1447                 goto tx_error;
1448         if (local)
1449                 return ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 1);
1450 
1451         ip_send_check(ip_hdr(skb));
1452 
1453         /* Another hack: avoid icmp_send in ip_fragment */
1454         skb->ignore_df = 1;
1455 
1456         ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 0);
1457 
1458         LeaveFunction(10);
1459         return NF_STOLEN;
1460 
1461   tx_error:
1462         kfree_skb(skb);
1463         LeaveFunction(10);
1464         return NF_STOLEN;
1465 }
1466 
1467 #ifdef CONFIG_IP_VS_IPV6
1468 int
1469 ip_vs_dr_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
1470                  struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
1471 {
1472         int local;
1473 
1474         EnterFunction(10);
1475 
1476         local = __ip_vs_get_out_rt_v6(cp->ipvs, cp->af, skb, cp->dest,
1477                                       &cp->daddr.in6,
1478                                       NULL, ipvsh, 0,
1479                                       IP_VS_RT_MODE_LOCAL |
1480                                       IP_VS_RT_MODE_NON_LOCAL |
1481                                       IP_VS_RT_MODE_KNOWN_NH);
1482         if (local < 0)
1483                 goto tx_error;
1484         if (local)
1485                 return ip_vs_send_or_cont(NFPROTO_IPV6, skb, cp, 1);
1486 
1487         /* Another hack: avoid icmp_send in ip_fragment */
1488         skb->ignore_df = 1;
1489 
1490         ip_vs_send_or_cont(NFPROTO_IPV6, skb, cp, 0);
1491 
1492         LeaveFunction(10);
1493         return NF_STOLEN;
1494 
1495 tx_error:
1496         kfree_skb(skb);
1497         LeaveFunction(10);
1498         return NF_STOLEN;
1499 }
1500 #endif
1501 
1502 
1503 /*
1504  *      ICMP packet transmitter
1505  *      called by the ip_vs_in_icmp
1506  */
1507 int
1508 ip_vs_icmp_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
1509                 struct ip_vs_protocol *pp, int offset, unsigned int hooknum,
1510                 struct ip_vs_iphdr *iph)
1511 {
1512         struct rtable   *rt;    /* Route to the other host */
1513         int rc;
1514         int local;
1515         int rt_mode, was_input;
1516 
1517         EnterFunction(10);
1518 
1519         /* The ICMP packet for VS/TUN, VS/DR and LOCALNODE will be
1520            forwarded directly here, because there is no need to
1521            translate address/port back */
1522         if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ) {
1523                 if (cp->packet_xmit)
1524                         rc = cp->packet_xmit(skb, cp, pp, iph);
1525                 else
1526                         rc = NF_ACCEPT;
1527                 /* do not touch skb anymore */
1528                 atomic_inc(&cp->in_pkts);
1529                 goto out;
1530         }
1531 
1532         /*
1533          * mangle and send the packet here (only for VS/NAT)
1534          */
1535         was_input = rt_is_input_route(skb_rtable(skb));
1536 
1537         /* LOCALNODE from FORWARD hook is not supported */
1538         rt_mode = (hooknum != NF_INET_FORWARD) ?
1539                   IP_VS_RT_MODE_LOCAL | IP_VS_RT_MODE_NON_LOCAL |
1540                   IP_VS_RT_MODE_RDR : IP_VS_RT_MODE_NON_LOCAL;
1541         local = __ip_vs_get_out_rt(cp->ipvs, cp->af, skb, cp->dest, cp->daddr.ip, rt_mode,
1542                                    NULL, iph);
1543         if (local < 0)
1544                 goto tx_error;
1545         rt = skb_rtable(skb);
1546 
1547         /*
1548          * Avoid duplicate tuple in reply direction for NAT traffic
1549          * to local address when connection is sync-ed
1550          */
1551 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
1552         if (cp->flags & IP_VS_CONN_F_SYNC && local) {
1553                 enum ip_conntrack_info ctinfo;
1554                 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
1555 
1556                 if (ct) {
1557                         IP_VS_DBG(10, "%s(): "
1558                                   "stopping DNAT to local address %pI4\n",
1559                                   __func__, &cp->daddr.ip);
1560                         goto tx_error;
1561                 }
1562         }
1563 #endif
1564 
1565         /* From world but DNAT to loopback address? */
1566         if (local && ipv4_is_loopback(cp->daddr.ip) && was_input) {
1567                 IP_VS_DBG(1, "%s(): "
1568                           "stopping DNAT to loopback %pI4\n",
1569                           __func__, &cp->daddr.ip);
1570                 goto tx_error;
1571         }
1572 
1573         /* copy-on-write the packet before mangling it */
1574         if (skb_ensure_writable(skb, offset))
1575                 goto tx_error;
1576 
1577         if (skb_cow(skb, rt->dst.dev->hard_header_len))
1578                 goto tx_error;
1579 
1580         ip_vs_nat_icmp(skb, pp, cp, 0);
1581 
1582         /* Another hack: avoid icmp_send in ip_fragment */
1583         skb->ignore_df = 1;
1584 
1585         rc = ip_vs_nat_send_or_cont(NFPROTO_IPV4, skb, cp, local);
1586         goto out;
1587 
1588   tx_error:
1589         kfree_skb(skb);
1590         rc = NF_STOLEN;
1591   out:
1592         LeaveFunction(10);
1593         return rc;
1594 }
1595 
1596 #ifdef CONFIG_IP_VS_IPV6
1597 int
1598 ip_vs_icmp_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
1599                 struct ip_vs_protocol *pp, int offset, unsigned int hooknum,
1600                 struct ip_vs_iphdr *ipvsh)
1601 {
1602         struct rt6_info *rt;    /* Route to the other host */
1603         int rc;
1604         int local;
1605         int rt_mode;
1606 
1607         EnterFunction(10);
1608 
1609         /* The ICMP packet for VS/TUN, VS/DR and LOCALNODE will be
1610            forwarded directly here, because there is no need to
1611            translate address/port back */
1612         if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ) {
1613                 if (cp->packet_xmit)
1614                         rc = cp->packet_xmit(skb, cp, pp, ipvsh);
1615                 else
1616                         rc = NF_ACCEPT;
1617                 /* do not touch skb anymore */
1618                 atomic_inc(&cp->in_pkts);
1619                 goto out;
1620         }
1621 
1622         /*
1623          * mangle and send the packet here (only for VS/NAT)
1624          */
1625 
1626         /* LOCALNODE from FORWARD hook is not supported */
1627         rt_mode = (hooknum != NF_INET_FORWARD) ?
1628                   IP_VS_RT_MODE_LOCAL | IP_VS_RT_MODE_NON_LOCAL |
1629                   IP_VS_RT_MODE_RDR : IP_VS_RT_MODE_NON_LOCAL;
1630         local = __ip_vs_get_out_rt_v6(cp->ipvs, cp->af, skb, cp->dest,
1631                                       &cp->daddr.in6, NULL, ipvsh, 0, rt_mode);
1632         if (local < 0)
1633                 goto tx_error;
1634         rt = (struct rt6_info *) skb_dst(skb);
1635         /*
1636          * Avoid duplicate tuple in reply direction for NAT traffic
1637          * to local address when connection is sync-ed
1638          */
1639 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
1640         if (cp->flags & IP_VS_CONN_F_SYNC && local) {
1641                 enum ip_conntrack_info ctinfo;
1642                 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
1643 
1644                 if (ct) {
1645                         IP_VS_DBG(10, "%s(): "
1646                                   "stopping DNAT to local address %pI6\n",
1647                                   __func__, &cp->daddr.in6);
1648                         goto tx_error;
1649                 }
1650         }
1651 #endif
1652 
1653         /* From world but DNAT to loopback address? */
1654         if (local && skb->dev && !(skb->dev->flags & IFF_LOOPBACK) &&
1655             ipv6_addr_type(&cp->daddr.in6) & IPV6_ADDR_LOOPBACK) {
1656                 IP_VS_DBG(1, "%s(): "
1657                           "stopping DNAT to loopback %pI6\n",
1658                           __func__, &cp->daddr.in6);
1659                 goto tx_error;
1660         }
1661 
1662         /* copy-on-write the packet before mangling it */
1663         if (skb_ensure_writable(skb, offset))
1664                 goto tx_error;
1665 
1666         if (skb_cow(skb, rt->dst.dev->hard_header_len))
1667                 goto tx_error;
1668 
1669         ip_vs_nat_icmp_v6(skb, pp, cp, 0);
1670 
1671         /* Another hack: avoid icmp_send in ip_fragment */
1672         skb->ignore_df = 1;
1673 
1674         rc = ip_vs_nat_send_or_cont(NFPROTO_IPV6, skb, cp, local);
1675         goto out;
1676 
1677 tx_error:
1678         kfree_skb(skb);
1679         rc = NF_STOLEN;
1680 out:
1681         LeaveFunction(10);
1682         return rc;
1683 }
1684 #endif
/* [<][>][^][v][top][bottom][index][help] */
root/net/netfilter/ipvs/ip_vs_xmit.c

DEFINITIONS
