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Linux/net/netfilter/ipvs/ip_vs_xmit.c

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  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  * - we can use dst without ref while sending in RCU section, we use
 21  * ref when returning NF_ACCEPT for NAT-ed packet via loopback
 22  * LOCAL_OUT rules:
 23  * - skb->dev is NULL, skb->protocol is not set (both are set in POST_ROUTING)
 24  * - skb->pkt_type is not set yet
 25  * - the only place where we can see skb->sk != NULL
 26  */
 27 
 28 #define KMSG_COMPONENT "IPVS"
 29 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 30 
 31 #include <linux/kernel.h>
 32 #include <linux/slab.h>
 33 #include <linux/tcp.h>                  /* for tcphdr */
 34 #include <net/ip.h>
 35 #include <net/tcp.h>                    /* for csum_tcpudp_magic */
 36 #include <net/udp.h>
 37 #include <net/icmp.h>                   /* for icmp_send */
 38 #include <net/route.h>                  /* for ip_route_output */
 39 #include <net/ipv6.h>
 40 #include <net/ip6_route.h>
 41 #include <net/ip_tunnels.h>
 42 #include <net/addrconf.h>
 43 #include <linux/icmpv6.h>
 44 #include <linux/netfilter.h>
 45 #include <linux/netfilter_ipv4.h>
 46 
 47 #include <net/ip_vs.h>
 48 
 49 enum {
 50         IP_VS_RT_MODE_LOCAL     = 1, /* Allow local dest */
 51         IP_VS_RT_MODE_NON_LOCAL = 2, /* Allow non-local dest */
 52         IP_VS_RT_MODE_RDR       = 4, /* Allow redirect from remote daddr to
 53                                       * local
 54                                       */
 55         IP_VS_RT_MODE_CONNECT   = 8, /* Always bind route to saddr */
 56         IP_VS_RT_MODE_KNOWN_NH  = 16,/* Route via remote addr */
 57         IP_VS_RT_MODE_TUNNEL    = 32,/* Tunnel mode */
 58 };
 59 
 60 static inline struct ip_vs_dest_dst *ip_vs_dest_dst_alloc(void)
 61 {
 62         return kmalloc(sizeof(struct ip_vs_dest_dst), GFP_ATOMIC);
 63 }
 64 
 65 static inline void ip_vs_dest_dst_free(struct ip_vs_dest_dst *dest_dst)
 66 {
 67         kfree(dest_dst);
 68 }
 69 
 70 /*
 71  *      Destination cache to speed up outgoing route lookup
 72  */
 73 static inline void
 74 __ip_vs_dst_set(struct ip_vs_dest *dest, struct ip_vs_dest_dst *dest_dst,
 75                 struct dst_entry *dst, u32 dst_cookie)
 76 {
 77         struct ip_vs_dest_dst *old;
 78 
 79         old = rcu_dereference_protected(dest->dest_dst,
 80                                         lockdep_is_held(&dest->dst_lock));
 81 
 82         if (dest_dst) {
 83                 dest_dst->dst_cache = dst;
 84                 dest_dst->dst_cookie = dst_cookie;
 85         }
 86         rcu_assign_pointer(dest->dest_dst, dest_dst);
 87 
 88         if (old)
 89                 call_rcu(&old->rcu_head, ip_vs_dest_dst_rcu_free);
 90 }
 91 
 92 static inline struct ip_vs_dest_dst *
 93 __ip_vs_dst_check(struct ip_vs_dest *dest)
 94 {
 95         struct ip_vs_dest_dst *dest_dst = rcu_dereference(dest->dest_dst);
 96         struct dst_entry *dst;
 97 
 98         if (!dest_dst)
 99                 return NULL;
100         dst = dest_dst->dst_cache;
101         if (dst->obsolete &&
102             dst->ops->check(dst, dest_dst->dst_cookie) == NULL)
103                 return NULL;
104         return dest_dst;
105 }
106 
107 static inline bool
108 __mtu_check_toobig_v6(const struct sk_buff *skb, u32 mtu)
109 {
110         if (IP6CB(skb)->frag_max_size) {
111                 /* frag_max_size tell us that, this packet have been
112                  * defragmented by netfilter IPv6 conntrack module.
113                  */
114                 if (IP6CB(skb)->frag_max_size > mtu)
115                         return true; /* largest fragment violate MTU */
116         }
117         else if (skb->len > mtu && !skb_is_gso(skb)) {
118                 return true; /* Packet size violate MTU size */
119         }
120         return false;
121 }
122 
123 /* Get route to daddr, update *saddr, optionally bind route to saddr */
124 static struct rtable *do_output_route4(struct net *net, __be32 daddr,
125                                        int rt_mode, __be32 *saddr)
126 {
127         struct flowi4 fl4;
128         struct rtable *rt;
129         int loop = 0;
130 
131         memset(&fl4, 0, sizeof(fl4));
132         fl4.daddr = daddr;
133         fl4.flowi4_flags = (rt_mode & IP_VS_RT_MODE_KNOWN_NH) ?
134                            FLOWI_FLAG_KNOWN_NH : 0;
135 
136 retry:
137         rt = ip_route_output_key(net, &fl4);
138         if (IS_ERR(rt)) {
139                 /* Invalid saddr ? */
140                 if (PTR_ERR(rt) == -EINVAL && *saddr &&
141                     rt_mode & IP_VS_RT_MODE_CONNECT && !loop) {
142                         *saddr = 0;
143                         flowi4_update_output(&fl4, 0, 0, daddr, 0);
144                         goto retry;
145                 }
146                 IP_VS_DBG_RL("ip_route_output error, dest: %pI4\n", &daddr);
147                 return NULL;
148         } else if (!*saddr && rt_mode & IP_VS_RT_MODE_CONNECT && fl4.saddr) {
149                 ip_rt_put(rt);
150                 *saddr = fl4.saddr;
151                 flowi4_update_output(&fl4, 0, 0, daddr, fl4.saddr);
152                 loop++;
153                 goto retry;
154         }
155         *saddr = fl4.saddr;
156         return rt;
157 }
158 
159 #ifdef CONFIG_IP_VS_IPV6
160 static inline int __ip_vs_is_local_route6(struct rt6_info *rt)
161 {
162         return rt->dst.dev && rt->dst.dev->flags & IFF_LOOPBACK;
163 }
164 #endif
165 
166 static inline bool crosses_local_route_boundary(int skb_af, struct sk_buff *skb,
167                                                 int rt_mode,
168                                                 bool new_rt_is_local)
169 {
170         bool rt_mode_allow_local = !!(rt_mode & IP_VS_RT_MODE_LOCAL);
171         bool rt_mode_allow_non_local = !!(rt_mode & IP_VS_RT_MODE_LOCAL);
172         bool rt_mode_allow_redirect = !!(rt_mode & IP_VS_RT_MODE_RDR);
173         bool source_is_loopback;
174         bool old_rt_is_local;
175 
176 #ifdef CONFIG_IP_VS_IPV6
177         if (skb_af == AF_INET6) {
178                 int addr_type = ipv6_addr_type(&ipv6_hdr(skb)->saddr);
179 
180                 source_is_loopback =
181                         (!skb->dev || skb->dev->flags & IFF_LOOPBACK) &&
182                         (addr_type & IPV6_ADDR_LOOPBACK);
183                 old_rt_is_local = __ip_vs_is_local_route6(
184                         (struct rt6_info *)skb_dst(skb));
185         } else
186 #endif
187         {
188                 source_is_loopback = ipv4_is_loopback(ip_hdr(skb)->saddr);
189                 old_rt_is_local = skb_rtable(skb)->rt_flags & RTCF_LOCAL;
190         }
191 
192         if (unlikely(new_rt_is_local)) {
193                 if (!rt_mode_allow_local)
194                         return true;
195                 if (!rt_mode_allow_redirect && !old_rt_is_local)
196                         return true;
197         } else {
198                 if (!rt_mode_allow_non_local)
199                         return true;
200                 if (source_is_loopback)
201                         return true;
202         }
203         return false;
204 }
205 
206 static inline void maybe_update_pmtu(int skb_af, struct sk_buff *skb, int mtu)
207 {
208         struct sock *sk = skb->sk;
209         struct rtable *ort = skb_rtable(skb);
210 
211         if (!skb->dev && sk && sk_fullsock(sk))
212                 ort->dst.ops->update_pmtu(&ort->dst, sk, NULL, mtu);
213 }
214 
215 static inline bool ensure_mtu_is_adequate(struct netns_ipvs *ipvs, int skb_af,
216                                           int rt_mode,
217                                           struct ip_vs_iphdr *ipvsh,
218                                           struct sk_buff *skb, int mtu)
219 {
220 #ifdef CONFIG_IP_VS_IPV6
221         if (skb_af == AF_INET6) {
222                 struct net *net = ipvs->net;
223 
224                 if (unlikely(__mtu_check_toobig_v6(skb, mtu))) {
225                         if (!skb->dev)
226                                 skb->dev = net->loopback_dev;
227                         /* only send ICMP too big on first fragment */
228                         if (!ipvsh->fragoffs && !ip_vs_iph_icmp(ipvsh))
229                                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
230                         IP_VS_DBG(1, "frag needed for %pI6c\n",
231                                   &ipv6_hdr(skb)->saddr);
232                         return false;
233                 }
234         } else
235 #endif
236         {
237                 /* If we're going to tunnel the packet and pmtu discovery
238                  * is disabled, we'll just fragment it anyway
239                  */
240                 if ((rt_mode & IP_VS_RT_MODE_TUNNEL) && !sysctl_pmtu_disc(ipvs))
241                         return true;
242 
243                 if (unlikely(ip_hdr(skb)->frag_off & htons(IP_DF) &&
244                              skb->len > mtu && !skb_is_gso(skb) &&
245                              !ip_vs_iph_icmp(ipvsh))) {
246                         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
247                                   htonl(mtu));
248                         IP_VS_DBG(1, "frag needed for %pI4\n",
249                                   &ip_hdr(skb)->saddr);
250                         return false;
251                 }
252         }
253 
254         return true;
255 }
256 
257 static inline bool decrement_ttl(struct netns_ipvs *ipvs,
258                                  int skb_af,
259                                  struct sk_buff *skb)
260 {
261         struct net *net = ipvs->net;
262 
263 #ifdef CONFIG_IP_VS_IPV6
264         if (skb_af == AF_INET6) {
265                 struct dst_entry *dst = skb_dst(skb);
266 
267                 /* check and decrement ttl */
268                 if (ipv6_hdr(skb)->hop_limit <= 1) {
269                         /* Force OUTPUT device used as source address */
270                         skb->dev = dst->dev;
271                         icmpv6_send(skb, ICMPV6_TIME_EXCEED,
272                                     ICMPV6_EXC_HOPLIMIT, 0);
273                         __IP6_INC_STATS(net, ip6_dst_idev(dst),
274                                         IPSTATS_MIB_INHDRERRORS);
275 
276                         return false;
277                 }
278 
279                 /* don't propagate ttl change to cloned packets */
280                 if (!skb_make_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_make_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 (mtu < 68) {
385                         IP_VS_DBG_RL("%s(): mtu less than 68\n", __func__);
386                         goto err_put;
387                 }
388                 maybe_update_pmtu(skb_af, skb, mtu);
389         }
390 
391         if (!ensure_mtu_is_adequate(ipvs, skb_af, rt_mode, ipvsh, skb, mtu))
392                 goto err_put;
393 
394         skb_dst_drop(skb);
395         if (noref) {
396                 if (!local)
397                         skb_dst_set_noref(skb, &rt->dst);
398                 else
399                         skb_dst_set(skb, dst_clone(&rt->dst));
400         } else
401                 skb_dst_set(skb, &rt->dst);
402 
403         return local;
404 
405 err_put:
406         if (!noref)
407                 ip_rt_put(rt);
408         return -1;
409 
410 err_unreach:
411         dst_link_failure(skb);
412         return -1;
413 }
414 
415 #ifdef CONFIG_IP_VS_IPV6
416 static struct dst_entry *
417 __ip_vs_route_output_v6(struct net *net, struct in6_addr *daddr,
418                         struct in6_addr *ret_saddr, int do_xfrm, int rt_mode)
419 {
420         struct dst_entry *dst;
421         struct flowi6 fl6 = {
422                 .daddr = *daddr,
423         };
424 
425         if (rt_mode & IP_VS_RT_MODE_KNOWN_NH)
426                 fl6.flowi6_flags = FLOWI_FLAG_KNOWN_NH;
427 
428         dst = ip6_route_output(net, NULL, &fl6);
429         if (dst->error)
430                 goto out_err;
431         if (!ret_saddr)
432                 return dst;
433         if (ipv6_addr_any(&fl6.saddr) &&
434             ipv6_dev_get_saddr(net, ip6_dst_idev(dst)->dev,
435                                &fl6.daddr, 0, &fl6.saddr) < 0)
436                 goto out_err;
437         if (do_xfrm) {
438                 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
439                 if (IS_ERR(dst)) {
440                         dst = NULL;
441                         goto out_err;
442                 }
443         }
444         *ret_saddr = fl6.saddr;
445         return dst;
446 
447 out_err:
448         dst_release(dst);
449         IP_VS_DBG_RL("ip6_route_output error, dest: %pI6\n", daddr);
450         return NULL;
451 }
452 
453 /*
454  * Get route to destination or remote server
455  */
456 static int
457 __ip_vs_get_out_rt_v6(struct netns_ipvs *ipvs, int skb_af, struct sk_buff *skb,
458                       struct ip_vs_dest *dest,
459                       struct in6_addr *daddr, struct in6_addr *ret_saddr,
460                       struct ip_vs_iphdr *ipvsh, int do_xfrm, int rt_mode)
461 {
462         struct net *net = ipvs->net;
463         struct ip_vs_dest_dst *dest_dst;
464         struct rt6_info *rt;                    /* Route to the other host */
465         struct dst_entry *dst;
466         int mtu;
467         int local, noref = 1;
468 
469         if (dest) {
470                 dest_dst = __ip_vs_dst_check(dest);
471                 if (likely(dest_dst))
472                         rt = (struct rt6_info *) dest_dst->dst_cache;
473                 else {
474                         u32 cookie;
475 
476                         dest_dst = ip_vs_dest_dst_alloc();
477                         spin_lock_bh(&dest->dst_lock);
478                         if (!dest_dst) {
479                                 __ip_vs_dst_set(dest, NULL, NULL, 0);
480                                 spin_unlock_bh(&dest->dst_lock);
481                                 goto err_unreach;
482                         }
483                         dst = __ip_vs_route_output_v6(net, &dest->addr.in6,
484                                                       &dest_dst->dst_saddr.in6,
485                                                       do_xfrm, rt_mode);
486                         if (!dst) {
487                                 __ip_vs_dst_set(dest, NULL, NULL, 0);
488                                 spin_unlock_bh(&dest->dst_lock);
489                                 ip_vs_dest_dst_free(dest_dst);
490                                 goto err_unreach;
491                         }
492                         rt = (struct rt6_info *) dst;
493                         cookie = rt6_get_cookie(rt);
494                         __ip_vs_dst_set(dest, dest_dst, &rt->dst, cookie);
495                         spin_unlock_bh(&dest->dst_lock);
496                         IP_VS_DBG(10, "new dst %pI6, src %pI6, refcnt=%d\n",
497                                   &dest->addr.in6, &dest_dst->dst_saddr.in6,
498                                   atomic_read(&rt->dst.__refcnt));
499                 }
500                 if (ret_saddr)
501                         *ret_saddr = dest_dst->dst_saddr.in6;
502         } else {
503                 noref = 0;
504                 dst = __ip_vs_route_output_v6(net, daddr, ret_saddr, do_xfrm,
505                                               rt_mode);
506                 if (!dst)
507                         goto err_unreach;
508                 rt = (struct rt6_info *) dst;
509         }
510 
511         local = __ip_vs_is_local_route6(rt);
512 
513         if (unlikely(crosses_local_route_boundary(skb_af, skb, rt_mode,
514                                                   local))) {
515                 IP_VS_DBG_RL("We are crossing local and non-local addresses"
516                              " daddr=%pI6\n", daddr);
517                 goto err_put;
518         }
519 
520         if (unlikely(local)) {
521                 /* skb to local stack, preserve old route */
522                 if (!noref)
523                         dst_release(&rt->dst);
524                 return local;
525         }
526 
527         if (!decrement_ttl(ipvs, skb_af, skb))
528                 goto err_put;
529 
530         /* MTU checking */
531         if (likely(!(rt_mode & IP_VS_RT_MODE_TUNNEL)))
532                 mtu = dst_mtu(&rt->dst);
533         else {
534                 mtu = dst_mtu(&rt->dst) - sizeof(struct ipv6hdr);
535                 if (mtu < IPV6_MIN_MTU) {
536                         IP_VS_DBG_RL("%s(): mtu less than %d\n", __func__,
537                                      IPV6_MIN_MTU);
538                         goto err_put;
539                 }
540                 maybe_update_pmtu(skb_af, skb, mtu);
541         }
542 
543         if (!ensure_mtu_is_adequate(ipvs, skb_af, rt_mode, ipvsh, skb, mtu))
544                 goto err_put;
545 
546         skb_dst_drop(skb);
547         if (noref) {
548                 if (!local)
549                         skb_dst_set_noref(skb, &rt->dst);
550                 else
551                         skb_dst_set(skb, dst_clone(&rt->dst));
552         } else
553                 skb_dst_set(skb, &rt->dst);
554 
555         return local;
556 
557 err_put:
558         if (!noref)
559                 dst_release(&rt->dst);
560         return -1;
561 
562 err_unreach:
563         /* The ip6_link_failure function requires the dev field to be set
564          * in order to get the net (further for the sake of fwmark
565          * reflection).
566          */
567         if (!skb->dev)
568                 skb->dev = skb_dst(skb)->dev;
569 
570         dst_link_failure(skb);
571         return -1;
572 }
573 #endif
574 
575 
576 /* return NF_ACCEPT to allow forwarding or other NF_xxx on error */
577 static inline int ip_vs_tunnel_xmit_prepare(struct sk_buff *skb,
578                                             struct ip_vs_conn *cp)
579 {
580         int ret = NF_ACCEPT;
581 
582         skb->ipvs_property = 1;
583         if (unlikely(cp->flags & IP_VS_CONN_F_NFCT))
584                 ret = ip_vs_confirm_conntrack(skb);
585         if (ret == NF_ACCEPT) {
586                 nf_reset(skb);
587                 skb_forward_csum(skb);
588         }
589         return ret;
590 }
591 
592 /* In the event of a remote destination, it's possible that we would have
593  * matches against an old socket (particularly a TIME-WAIT socket). This
594  * causes havoc down the line (ip_local_out et. al. expect regular sockets
595  * and invalid memory accesses will happen) so simply drop the association
596  * in this case.
597 */
598 static inline void ip_vs_drop_early_demux_sk(struct sk_buff *skb)
599 {
600         /* If dev is set, the packet came from the LOCAL_IN callback and
601          * not from a local TCP socket.
602          */
603         if (skb->dev)
604                 skb_orphan(skb);
605 }
606 
607 /* return NF_STOLEN (sent) or NF_ACCEPT if local=1 (not sent) */
608 static inline int ip_vs_nat_send_or_cont(int pf, struct sk_buff *skb,
609                                          struct ip_vs_conn *cp, int local)
610 {
611         int ret = NF_STOLEN;
612 
613         skb->ipvs_property = 1;
614         if (likely(!(cp->flags & IP_VS_CONN_F_NFCT)))
615                 ip_vs_notrack(skb);
616         else
617                 ip_vs_update_conntrack(skb, cp, 1);
618 
619         /* Remove the early_demux association unless it's bound for the
620          * exact same port and address on this host after translation.
621          */
622         if (!local || cp->vport != cp->dport ||
623             !ip_vs_addr_equal(cp->af, &cp->vaddr, &cp->daddr))
624                 ip_vs_drop_early_demux_sk(skb);
625 
626         if (!local) {
627                 skb_forward_csum(skb);
628                 NF_HOOK(pf, NF_INET_LOCAL_OUT, cp->ipvs->net, NULL, skb,
629                         NULL, skb_dst(skb)->dev, dst_output);
630         } else
631                 ret = NF_ACCEPT;
632 
633         return ret;
634 }
635 
636 /* return NF_STOLEN (sent) or NF_ACCEPT if local=1 (not sent) */
637 static inline int ip_vs_send_or_cont(int pf, struct sk_buff *skb,
638                                      struct ip_vs_conn *cp, int local)
639 {
640         int ret = NF_STOLEN;
641 
642         skb->ipvs_property = 1;
643         if (likely(!(cp->flags & IP_VS_CONN_F_NFCT)))
644                 ip_vs_notrack(skb);
645         if (!local) {
646                 ip_vs_drop_early_demux_sk(skb);
647                 skb_forward_csum(skb);
648                 NF_HOOK(pf, NF_INET_LOCAL_OUT, cp->ipvs->net, NULL, skb,
649                         NULL, skb_dst(skb)->dev, dst_output);
650         } else
651                 ret = NF_ACCEPT;
652         return ret;
653 }
654 
655 
656 /*
657  *      NULL transmitter (do nothing except return NF_ACCEPT)
658  */
659 int
660 ip_vs_null_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
661                 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
662 {
663         /* we do not touch skb and do not need pskb ptr */
664         return ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 1);
665 }
666 
667 
668 /*
669  *      Bypass transmitter
670  *      Let packets bypass the destination when the destination is not
671  *      available, it may be only used in transparent cache cluster.
672  */
673 int
674 ip_vs_bypass_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
675                   struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
676 {
677         struct iphdr  *iph = ip_hdr(skb);
678 
679         EnterFunction(10);
680 
681         if (__ip_vs_get_out_rt(cp->ipvs, cp->af, skb, NULL, iph->daddr,
682                                IP_VS_RT_MODE_NON_LOCAL, NULL, ipvsh) < 0)
683                 goto tx_error;
684 
685         ip_send_check(iph);
686 
687         /* Another hack: avoid icmp_send in ip_fragment */
688         skb->ignore_df = 1;
689 
690         ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 0);
691 
692         LeaveFunction(10);
693         return NF_STOLEN;
694 
695  tx_error:
696         kfree_skb(skb);
697         LeaveFunction(10);
698         return NF_STOLEN;
699 }
700 
701 #ifdef CONFIG_IP_VS_IPV6
702 int
703 ip_vs_bypass_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
704                      struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
705 {
706         struct ipv6hdr *iph = ipv6_hdr(skb);
707 
708         EnterFunction(10);
709 
710         if (__ip_vs_get_out_rt_v6(cp->ipvs, cp->af, skb, NULL,
711                                   &iph->daddr, NULL,
712                                   ipvsh, 0, IP_VS_RT_MODE_NON_LOCAL) < 0)
713                 goto tx_error;
714 
715         /* Another hack: avoid icmp_send in ip_fragment */
716         skb->ignore_df = 1;
717 
718         ip_vs_send_or_cont(NFPROTO_IPV6, skb, cp, 0);
719 
720         LeaveFunction(10);
721         return NF_STOLEN;
722 
723  tx_error:
724         kfree_skb(skb);
725         LeaveFunction(10);
726         return NF_STOLEN;
727 }
728 #endif
729 
730 /*
731  *      NAT transmitter (only for outside-to-inside nat forwarding)
732  *      Not used for related ICMP
733  */
734 int
735 ip_vs_nat_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
736                struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
737 {
738         struct rtable *rt;              /* Route to the other host */
739         int local, rc, was_input;
740 
741         EnterFunction(10);
742 
743         /* check if it is a connection of no-client-port */
744         if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT)) {
745                 __be16 _pt, *p;
746 
747                 p = skb_header_pointer(skb, ipvsh->len, sizeof(_pt), &_pt);
748                 if (p == NULL)
749                         goto tx_error;
750                 ip_vs_conn_fill_cport(cp, *p);
751                 IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
752         }
753 
754         was_input = rt_is_input_route(skb_rtable(skb));
755         local = __ip_vs_get_out_rt(cp->ipvs, cp->af, skb, cp->dest, cp->daddr.ip,
756                                    IP_VS_RT_MODE_LOCAL |
757                                    IP_VS_RT_MODE_NON_LOCAL |
758                                    IP_VS_RT_MODE_RDR, NULL, ipvsh);
759         if (local < 0)
760                 goto tx_error;
761         rt = skb_rtable(skb);
762         /*
763          * Avoid duplicate tuple in reply direction for NAT traffic
764          * to local address when connection is sync-ed
765          */
766 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
767         if (cp->flags & IP_VS_CONN_F_SYNC && local) {
768                 enum ip_conntrack_info ctinfo;
769                 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
770 
771                 if (ct) {
772                         IP_VS_DBG_RL_PKT(10, AF_INET, pp, skb, ipvsh->off,
773                                          "ip_vs_nat_xmit(): "
774                                          "stopping DNAT to local address");
775                         goto tx_error;
776                 }
777         }
778 #endif
779 
780         /* From world but DNAT to loopback address? */
781         if (local && ipv4_is_loopback(cp->daddr.ip) && was_input) {
782                 IP_VS_DBG_RL_PKT(1, AF_INET, pp, skb, ipvsh->off,
783                                  "ip_vs_nat_xmit(): stopping DNAT to loopback "
784                                  "address");
785                 goto tx_error;
786         }
787 
788         /* copy-on-write the packet before mangling it */
789         if (!skb_make_writable(skb, sizeof(struct iphdr)))
790                 goto tx_error;
791 
792         if (skb_cow(skb, rt->dst.dev->hard_header_len))
793                 goto tx_error;
794 
795         /* mangle the packet */
796         if (pp->dnat_handler && !pp->dnat_handler(skb, pp, cp, ipvsh))
797                 goto tx_error;
798         ip_hdr(skb)->daddr = cp->daddr.ip;
799         ip_send_check(ip_hdr(skb));
800 
801         IP_VS_DBG_PKT(10, AF_INET, pp, skb, ipvsh->off, "After DNAT");
802 
803         /* FIXME: when application helper enlarges the packet and the length
804            is larger than the MTU of outgoing device, there will be still
805            MTU problem. */
806 
807         /* Another hack: avoid icmp_send in ip_fragment */
808         skb->ignore_df = 1;
809 
810         rc = ip_vs_nat_send_or_cont(NFPROTO_IPV4, skb, cp, local);
811 
812         LeaveFunction(10);
813         return rc;
814 
815   tx_error:
816         kfree_skb(skb);
817         LeaveFunction(10);
818         return NF_STOLEN;
819 }
820 
821 #ifdef CONFIG_IP_VS_IPV6
822 int
823 ip_vs_nat_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
824                   struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
825 {
826         struct rt6_info *rt;            /* Route to the other host */
827         int local, rc;
828 
829         EnterFunction(10);
830 
831         /* check if it is a connection of no-client-port */
832         if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT && !ipvsh->fragoffs)) {
833                 __be16 _pt, *p;
834                 p = skb_header_pointer(skb, ipvsh->len, sizeof(_pt), &_pt);
835                 if (p == NULL)
836                         goto tx_error;
837                 ip_vs_conn_fill_cport(cp, *p);
838                 IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
839         }
840 
841         local = __ip_vs_get_out_rt_v6(cp->ipvs, cp->af, skb, cp->dest,
842                                       &cp->daddr.in6,
843                                       NULL, ipvsh, 0,
844                                       IP_VS_RT_MODE_LOCAL |
845                                       IP_VS_RT_MODE_NON_LOCAL |
846                                       IP_VS_RT_MODE_RDR);
847         if (local < 0)
848                 goto tx_error;
849         rt = (struct rt6_info *) skb_dst(skb);
850         /*
851          * Avoid duplicate tuple in reply direction for NAT traffic
852          * to local address when connection is sync-ed
853          */
854 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
855         if (cp->flags & IP_VS_CONN_F_SYNC && local) {
856                 enum ip_conntrack_info ctinfo;
857                 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
858 
859                 if (ct) {
860                         IP_VS_DBG_RL_PKT(10, AF_INET6, pp, skb, ipvsh->off,
861                                          "ip_vs_nat_xmit_v6(): "
862                                          "stopping DNAT to local address");
863                         goto tx_error;
864                 }
865         }
866 #endif
867 
868         /* From world but DNAT to loopback address? */
869         if (local && skb->dev && !(skb->dev->flags & IFF_LOOPBACK) &&
870             ipv6_addr_type(&cp->daddr.in6) & IPV6_ADDR_LOOPBACK) {
871                 IP_VS_DBG_RL_PKT(1, AF_INET6, pp, skb, ipvsh->off,
872                                  "ip_vs_nat_xmit_v6(): "
873                                  "stopping DNAT to loopback address");
874                 goto tx_error;
875         }
876 
877         /* copy-on-write the packet before mangling it */
878         if (!skb_make_writable(skb, sizeof(struct ipv6hdr)))
879                 goto tx_error;
880 
881         if (skb_cow(skb, rt->dst.dev->hard_header_len))
882                 goto tx_error;
883 
884         /* mangle the packet */
885         if (pp->dnat_handler && !pp->dnat_handler(skb, pp, cp, ipvsh))
886                 goto tx_error;
887         ipv6_hdr(skb)->daddr = cp->daddr.in6;
888 
889         IP_VS_DBG_PKT(10, AF_INET6, pp, skb, ipvsh->off, "After DNAT");
890 
891         /* FIXME: when application helper enlarges the packet and the length
892            is larger than the MTU of outgoing device, there will be still
893            MTU problem. */
894 
895         /* Another hack: avoid icmp_send in ip_fragment */
896         skb->ignore_df = 1;
897 
898         rc = ip_vs_nat_send_or_cont(NFPROTO_IPV6, skb, cp, local);
899 
900         LeaveFunction(10);
901         return rc;
902 
903 tx_error:
904         LeaveFunction(10);
905         kfree_skb(skb);
906         return NF_STOLEN;
907 }
908 #endif
909 
910 /* When forwarding a packet, we must ensure that we've got enough headroom
911  * for the encapsulation packet in the skb.  This also gives us an
912  * opportunity to figure out what the payload_len, dsfield, ttl, and df
913  * values should be, so that we won't need to look at the old ip header
914  * again
915  */
916 static struct sk_buff *
917 ip_vs_prepare_tunneled_skb(struct sk_buff *skb, int skb_af,
918                            unsigned int max_headroom, __u8 *next_protocol,
919                            __u32 *payload_len, __u8 *dsfield, __u8 *ttl,
920                            __be16 *df)
921 {
922         struct sk_buff *new_skb = NULL;
923         struct iphdr *old_iph = NULL;
924         __u8 old_dsfield;
925 #ifdef CONFIG_IP_VS_IPV6
926         struct ipv6hdr *old_ipv6h = NULL;
927 #endif
928 
929         ip_vs_drop_early_demux_sk(skb);
930 
931         if (skb_headroom(skb) < max_headroom || skb_cloned(skb)) {
932                 new_skb = skb_realloc_headroom(skb, max_headroom);
933                 if (!new_skb)
934                         goto error;
935                 if (skb->sk)
936                         skb_set_owner_w(new_skb, skb->sk);
937                 consume_skb(skb);
938                 skb = new_skb;
939         }
940 
941 #ifdef CONFIG_IP_VS_IPV6
942         if (skb_af == AF_INET6) {
943                 old_ipv6h = ipv6_hdr(skb);
944                 *next_protocol = IPPROTO_IPV6;
945                 if (payload_len)
946                         *payload_len =
947                                 ntohs(old_ipv6h->payload_len) +
948                                 sizeof(*old_ipv6h);
949                 old_dsfield = ipv6_get_dsfield(old_ipv6h);
950                 *ttl = old_ipv6h->hop_limit;
951                 if (df)
952                         *df = 0;
953         } else
954 #endif
955         {
956                 old_iph = ip_hdr(skb);
957                 /* Copy DF, reset fragment offset and MF */
958                 if (df)
959                         *df = (old_iph->frag_off & htons(IP_DF));
960                 *next_protocol = IPPROTO_IPIP;
961 
962                 /* fix old IP header checksum */
963                 ip_send_check(old_iph);
964                 old_dsfield = ipv4_get_dsfield(old_iph);
965                 *ttl = old_iph->ttl;
966                 if (payload_len)
967                         *payload_len = ntohs(old_iph->tot_len);
968         }
969 
970         /* Implement full-functionality option for ECN encapsulation */
971         *dsfield = INET_ECN_encapsulate(old_dsfield, old_dsfield);
972 
973         return skb;
974 error:
975         kfree_skb(skb);
976         return ERR_PTR(-ENOMEM);
977 }
978 
979 static inline int __tun_gso_type_mask(int encaps_af, int orig_af)
980 {
981         switch (encaps_af) {
982         case AF_INET:
983                 return SKB_GSO_IPXIP4;
984         case AF_INET6:
985                 return SKB_GSO_IPXIP6;
986         default:
987                 return 0;
988         }
989 }
990 
991 /*
992  *   IP Tunneling transmitter
993  *
994  *   This function encapsulates the packet in a new IP packet, its
995  *   destination will be set to cp->daddr. Most code of this function
996  *   is taken from ipip.c.
997  *
998  *   It is used in VS/TUN cluster. The load balancer selects a real
999  *   server from a cluster based on a scheduling algorithm,
1000  *   encapsulates the request packet and forwards it to the selected
1001  *   server. For example, all real servers are configured with
1002  *   "ifconfig tunl0 <Virtual IP Address> up". When the server receives
1003  *   the encapsulated packet, it will decapsulate the packet, processe
1004  *   the request and return the response packets directly to the client
1005  *   without passing the load balancer. This can greatly increase the
1006  *   scalability of virtual server.
1007  *
1008  *   Used for ANY protocol
1009  */
1010 int
1011 ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
1012                   struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
1013 {
1014         struct netns_ipvs *ipvs = cp->ipvs;
1015         struct net *net = ipvs->net;
1016         struct rtable *rt;                      /* Route to the other host */
1017         __be32 saddr;                           /* Source for tunnel */
1018         struct net_device *tdev;                /* Device to other host */
1019         __u8 next_protocol = 0;
1020         __u8 dsfield = 0;
1021         __u8 ttl = 0;
1022         __be16 df = 0;
1023         __be16 *dfp = NULL;
1024         struct iphdr  *iph;                     /* Our new IP header */
1025         unsigned int max_headroom;              /* The extra header space needed */
1026         int ret, local;
1027 
1028         EnterFunction(10);
1029 
1030         local = __ip_vs_get_out_rt(ipvs, cp->af, skb, cp->dest, cp->daddr.ip,
1031                                    IP_VS_RT_MODE_LOCAL |
1032                                    IP_VS_RT_MODE_NON_LOCAL |
1033                                    IP_VS_RT_MODE_CONNECT |
1034                                    IP_VS_RT_MODE_TUNNEL, &saddr, ipvsh);
1035         if (local < 0)
1036                 goto tx_error;
1037         if (local)
1038                 return ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 1);
1039 
1040         rt = skb_rtable(skb);
1041         tdev = rt->dst.dev;
1042 
1043         /*
1044          * Okay, now see if we can stuff it in the buffer as-is.
1045          */
1046         max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct iphdr);
1047 
1048         /* We only care about the df field if sysctl_pmtu_disc(ipvs) is set */
1049         dfp = sysctl_pmtu_disc(ipvs) ? &df : NULL;
1050         skb = ip_vs_prepare_tunneled_skb(skb, cp->af, max_headroom,
1051                                          &next_protocol, NULL, &dsfield,
1052                                          &ttl, dfp);
1053         if (IS_ERR(skb))
1054                 goto tx_error;
1055 
1056         if (iptunnel_handle_offloads(skb, __tun_gso_type_mask(AF_INET, cp->af)))
1057                 goto tx_error;
1058 
1059         skb->transport_header = skb->network_header;
1060 
1061         skb_push(skb, sizeof(struct iphdr));
1062         skb_reset_network_header(skb);
1063         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1064 
1065         /*
1066          *      Push down and install the IPIP header.
1067          */
1068         iph                     =       ip_hdr(skb);
1069         iph->version            =       4;
1070         iph->ihl                =       sizeof(struct iphdr)>>2;
1071         iph->frag_off           =       df;
1072         iph->protocol           =       next_protocol;
1073         iph->tos                =       dsfield;
1074         iph->daddr              =       cp->daddr.ip;
1075         iph->saddr              =       saddr;
1076         iph->ttl                =       ttl;
1077         ip_select_ident(net, skb, NULL);
1078 
1079         /* Another hack: avoid icmp_send in ip_fragment */
1080         skb->ignore_df = 1;
1081 
1082         ret = ip_vs_tunnel_xmit_prepare(skb, cp);
1083         if (ret == NF_ACCEPT)
1084                 ip_local_out(net, skb->sk, skb);
1085         else if (ret == NF_DROP)
1086                 kfree_skb(skb);
1087 
1088         LeaveFunction(10);
1089 
1090         return NF_STOLEN;
1091 
1092   tx_error:
1093         if (!IS_ERR(skb))
1094                 kfree_skb(skb);
1095         LeaveFunction(10);
1096         return NF_STOLEN;
1097 }
1098 
1099 #ifdef CONFIG_IP_VS_IPV6
1100 int
1101 ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
1102                      struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
1103 {
1104         struct rt6_info *rt;            /* Route to the other host */
1105         struct in6_addr saddr;          /* Source for tunnel */
1106         struct net_device *tdev;        /* Device to other host */
1107         __u8 next_protocol = 0;
1108         __u32 payload_len = 0;
1109         __u8 dsfield = 0;
1110         __u8 ttl = 0;
1111         struct ipv6hdr  *iph;           /* Our new IP header */
1112         unsigned int max_headroom;      /* The extra header space needed */
1113         int ret, local;
1114 
1115         EnterFunction(10);
1116 
1117         local = __ip_vs_get_out_rt_v6(cp->ipvs, cp->af, skb, cp->dest,
1118                                       &cp->daddr.in6,
1119                                       &saddr, ipvsh, 1,
1120                                       IP_VS_RT_MODE_LOCAL |
1121                                       IP_VS_RT_MODE_NON_LOCAL |
1122                                       IP_VS_RT_MODE_TUNNEL);
1123         if (local < 0)
1124                 goto tx_error;
1125         if (local)
1126                 return ip_vs_send_or_cont(NFPROTO_IPV6, skb, cp, 1);
1127 
1128         rt = (struct rt6_info *) skb_dst(skb);
1129         tdev = rt->dst.dev;
1130 
1131         /*
1132          * Okay, now see if we can stuff it in the buffer as-is.
1133          */
1134         max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct ipv6hdr);
1135 
1136         skb = ip_vs_prepare_tunneled_skb(skb, cp->af, max_headroom,
1137                                          &next_protocol, &payload_len,
1138                                          &dsfield, &ttl, NULL);
1139         if (IS_ERR(skb))
1140                 goto tx_error;
1141 
1142         if (iptunnel_handle_offloads(skb, __tun_gso_type_mask(AF_INET6, cp->af)))
1143                 goto tx_error;
1144 
1145         skb->transport_header = skb->network_header;
1146 
1147         skb_push(skb, sizeof(struct ipv6hdr));
1148         skb_reset_network_header(skb);
1149         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1150 
1151         /*
1152          *      Push down and install the IPIP header.
1153          */
1154         iph                     =       ipv6_hdr(skb);
1155         iph->version            =       6;
1156         iph->nexthdr            =       next_protocol;
1157         iph->payload_len        =       htons(payload_len);
1158         memset(&iph->flow_lbl, 0, sizeof(iph->flow_lbl));
1159         ipv6_change_dsfield(iph, 0, dsfield);
1160         iph->daddr = cp->daddr.in6;
1161         iph->saddr = saddr;
1162         iph->hop_limit          =       ttl;
1163 
1164         /* Another hack: avoid icmp_send in ip_fragment */
1165         skb->ignore_df = 1;
1166 
1167         ret = ip_vs_tunnel_xmit_prepare(skb, cp);
1168         if (ret == NF_ACCEPT)
1169                 ip6_local_out(cp->ipvs->net, skb->sk, skb);
1170         else if (ret == NF_DROP)
1171                 kfree_skb(skb);
1172 
1173         LeaveFunction(10);
1174 
1175         return NF_STOLEN;
1176 
1177 tx_error:
1178         if (!IS_ERR(skb))
1179                 kfree_skb(skb);
1180         LeaveFunction(10);
1181         return NF_STOLEN;
1182 }
1183 #endif
1184 
1185 
1186 /*
1187  *      Direct Routing transmitter
1188  *      Used for ANY protocol
1189  */
1190 int
1191 ip_vs_dr_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
1192               struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
1193 {
1194         int local;
1195 
1196         EnterFunction(10);
1197 
1198         local = __ip_vs_get_out_rt(cp->ipvs, cp->af, skb, cp->dest, cp->daddr.ip,
1199                                    IP_VS_RT_MODE_LOCAL |
1200                                    IP_VS_RT_MODE_NON_LOCAL |
1201                                    IP_VS_RT_MODE_KNOWN_NH, NULL, ipvsh);
1202         if (local < 0)
1203                 goto tx_error;
1204         if (local)
1205                 return ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 1);
1206 
1207         ip_send_check(ip_hdr(skb));
1208 
1209         /* Another hack: avoid icmp_send in ip_fragment */
1210         skb->ignore_df = 1;
1211 
1212         ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 0);
1213 
1214         LeaveFunction(10);
1215         return NF_STOLEN;
1216 
1217   tx_error:
1218         kfree_skb(skb);
1219         LeaveFunction(10);
1220         return NF_STOLEN;
1221 }
1222 
1223 #ifdef CONFIG_IP_VS_IPV6
1224 int
1225 ip_vs_dr_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
1226                  struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
1227 {
1228         int local;
1229 
1230         EnterFunction(10);
1231 
1232         local = __ip_vs_get_out_rt_v6(cp->ipvs, cp->af, skb, cp->dest,
1233                                       &cp->daddr.in6,
1234                                       NULL, ipvsh, 0,
1235                                       IP_VS_RT_MODE_LOCAL |
1236                                       IP_VS_RT_MODE_NON_LOCAL |
1237                                       IP_VS_RT_MODE_KNOWN_NH);
1238         if (local < 0)
1239                 goto tx_error;
1240         if (local)
1241                 return ip_vs_send_or_cont(NFPROTO_IPV6, skb, cp, 1);
1242 
1243         /* Another hack: avoid icmp_send in ip_fragment */
1244         skb->ignore_df = 1;
1245 
1246         ip_vs_send_or_cont(NFPROTO_IPV6, skb, cp, 0);
1247 
1248         LeaveFunction(10);
1249         return NF_STOLEN;
1250 
1251 tx_error:
1252         kfree_skb(skb);
1253         LeaveFunction(10);
1254         return NF_STOLEN;
1255 }
1256 #endif
1257 
1258 
1259 /*
1260  *      ICMP packet transmitter
1261  *      called by the ip_vs_in_icmp
1262  */
1263 int
1264 ip_vs_icmp_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
1265                 struct ip_vs_protocol *pp, int offset, unsigned int hooknum,
1266                 struct ip_vs_iphdr *iph)
1267 {
1268         struct rtable   *rt;    /* Route to the other host */
1269         int rc;
1270         int local;
1271         int rt_mode, was_input;
1272 
1273         EnterFunction(10);
1274 
1275         /* The ICMP packet for VS/TUN, VS/DR and LOCALNODE will be
1276            forwarded directly here, because there is no need to
1277            translate address/port back */
1278         if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ) {
1279                 if (cp->packet_xmit)
1280                         rc = cp->packet_xmit(skb, cp, pp, iph);
1281                 else
1282                         rc = NF_ACCEPT;
1283                 /* do not touch skb anymore */
1284                 atomic_inc(&cp->in_pkts);
1285                 goto out;
1286         }
1287 
1288         /*
1289          * mangle and send the packet here (only for VS/NAT)
1290          */
1291         was_input = rt_is_input_route(skb_rtable(skb));
1292 
1293         /* LOCALNODE from FORWARD hook is not supported */
1294         rt_mode = (hooknum != NF_INET_FORWARD) ?
1295                   IP_VS_RT_MODE_LOCAL | IP_VS_RT_MODE_NON_LOCAL |
1296                   IP_VS_RT_MODE_RDR : IP_VS_RT_MODE_NON_LOCAL;
1297         local = __ip_vs_get_out_rt(cp->ipvs, cp->af, skb, cp->dest, cp->daddr.ip, rt_mode,
1298                                    NULL, iph);
1299         if (local < 0)
1300                 goto tx_error;
1301         rt = skb_rtable(skb);
1302 
1303         /*
1304          * Avoid duplicate tuple in reply direction for NAT traffic
1305          * to local address when connection is sync-ed
1306          */
1307 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
1308         if (cp->flags & IP_VS_CONN_F_SYNC && local) {
1309                 enum ip_conntrack_info ctinfo;
1310                 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
1311 
1312                 if (ct) {
1313                         IP_VS_DBG(10, "%s(): "
1314                                   "stopping DNAT to local address %pI4\n",
1315                                   __func__, &cp->daddr.ip);
1316                         goto tx_error;
1317                 }
1318         }
1319 #endif
1320 
1321         /* From world but DNAT to loopback address? */
1322         if (local && ipv4_is_loopback(cp->daddr.ip) && was_input) {
1323                 IP_VS_DBG(1, "%s(): "
1324                           "stopping DNAT to loopback %pI4\n",
1325                           __func__, &cp->daddr.ip);
1326                 goto tx_error;
1327         }
1328 
1329         /* copy-on-write the packet before mangling it */
1330         if (!skb_make_writable(skb, offset))
1331                 goto tx_error;
1332 
1333         if (skb_cow(skb, rt->dst.dev->hard_header_len))
1334                 goto tx_error;
1335 
1336         ip_vs_nat_icmp(skb, pp, cp, 0);
1337 
1338         /* Another hack: avoid icmp_send in ip_fragment */
1339         skb->ignore_df = 1;
1340 
1341         rc = ip_vs_nat_send_or_cont(NFPROTO_IPV4, skb, cp, local);
1342         goto out;
1343 
1344   tx_error:
1345         kfree_skb(skb);
1346         rc = NF_STOLEN;
1347   out:
1348         LeaveFunction(10);
1349         return rc;
1350 }
1351 
1352 #ifdef CONFIG_IP_VS_IPV6
1353 int
1354 ip_vs_icmp_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
1355                 struct ip_vs_protocol *pp, int offset, unsigned int hooknum,
1356                 struct ip_vs_iphdr *ipvsh)
1357 {
1358         struct rt6_info *rt;    /* Route to the other host */
1359         int rc;
1360         int local;
1361         int rt_mode;
1362 
1363         EnterFunction(10);
1364 
1365         /* The ICMP packet for VS/TUN, VS/DR and LOCALNODE will be
1366            forwarded directly here, because there is no need to
1367            translate address/port back */
1368         if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ) {
1369                 if (cp->packet_xmit)
1370                         rc = cp->packet_xmit(skb, cp, pp, ipvsh);
1371                 else
1372                         rc = NF_ACCEPT;
1373                 /* do not touch skb anymore */
1374                 atomic_inc(&cp->in_pkts);
1375                 goto out;
1376         }
1377 
1378         /*
1379          * mangle and send the packet here (only for VS/NAT)
1380          */
1381 
1382         /* LOCALNODE from FORWARD hook is not supported */
1383         rt_mode = (hooknum != NF_INET_FORWARD) ?
1384                   IP_VS_RT_MODE_LOCAL | IP_VS_RT_MODE_NON_LOCAL |
1385                   IP_VS_RT_MODE_RDR : IP_VS_RT_MODE_NON_LOCAL;
1386         local = __ip_vs_get_out_rt_v6(cp->ipvs, cp->af, skb, cp->dest,
1387                                       &cp->daddr.in6, NULL, ipvsh, 0, rt_mode);
1388         if (local < 0)
1389                 goto tx_error;
1390         rt = (struct rt6_info *) skb_dst(skb);
1391         /*
1392          * Avoid duplicate tuple in reply direction for NAT traffic
1393          * to local address when connection is sync-ed
1394          */
1395 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
1396         if (cp->flags & IP_VS_CONN_F_SYNC && local) {
1397                 enum ip_conntrack_info ctinfo;
1398                 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
1399 
1400                 if (ct) {
1401                         IP_VS_DBG(10, "%s(): "
1402                                   "stopping DNAT to local address %pI6\n",
1403                                   __func__, &cp->daddr.in6);
1404                         goto tx_error;
1405                 }
1406         }
1407 #endif
1408 
1409         /* From world but DNAT to loopback address? */
1410         if (local && skb->dev && !(skb->dev->flags & IFF_LOOPBACK) &&
1411             ipv6_addr_type(&cp->daddr.in6) & IPV6_ADDR_LOOPBACK) {
1412                 IP_VS_DBG(1, "%s(): "
1413                           "stopping DNAT to loopback %pI6\n",
1414                           __func__, &cp->daddr.in6);
1415                 goto tx_error;
1416         }
1417 
1418         /* copy-on-write the packet before mangling it */
1419         if (!skb_make_writable(skb, offset))
1420                 goto tx_error;
1421 
1422         if (skb_cow(skb, rt->dst.dev->hard_header_len))
1423                 goto tx_error;
1424 
1425         ip_vs_nat_icmp_v6(skb, pp, cp, 0);
1426 
1427         /* Another hack: avoid icmp_send in ip_fragment */
1428         skb->ignore_df = 1;
1429 
1430         rc = ip_vs_nat_send_or_cont(NFPROTO_IPV6, skb, cp, local);
1431         goto out;
1432 
1433 tx_error:
1434         kfree_skb(skb);
1435         rc = NF_STOLEN;
1436 out:
1437         LeaveFunction(10);
1438         return rc;
1439 }
1440 #endif
1441 

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