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
ip_vs_dest_dst_alloc(void)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
ip_vs_dest_dst_free(struct ip_vs_dest_dst * dest_dst)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
__ip_vs_dst_set(struct ip_vs_dest * dest,struct ip_vs_dest_dst * dest_dst,struct dst_entry * dst,u32 dst_cookie)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 *
__ip_vs_dst_check(struct ip_vs_dest * dest)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
__mtu_check_toobig_v6(const struct sk_buff * skb,u32 mtu)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 */
do_output_route4(struct net * net,__be32 daddr,int rt_mode,__be32 * 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
__ip_vs_is_local_route6(struct rt6_info * rt)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
crosses_local_route_boundary(int skb_af,struct sk_buff * skb,int rt_mode,bool new_rt_is_local)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
maybe_update_pmtu(int skb_af,struct sk_buff * skb,int mtu)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
ensure_mtu_is_adequate(int skb_af,int rt_mode,struct ip_vs_iphdr * ipvsh,struct sk_buff * skb,int mtu)215 static inline bool ensure_mtu_is_adequate(int skb_af, 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 = dev_net(skb_dst(skb)->dev);
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)
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 struct netns_ipvs *ipvs = net_ipvs(skb_net(skb));
237
238 /* If we're going to tunnel the packet and pmtu discovery
239 * is disabled, we'll just fragment it anyway
240 */
241 if ((rt_mode & IP_VS_RT_MODE_TUNNEL) && !sysctl_pmtu_disc(ipvs))
242 return true;
243
244 if (unlikely(ip_hdr(skb)->frag_off & htons(IP_DF) &&
245 skb->len > mtu && !skb_is_gso(skb))) {
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 /* Get route to destination or remote server */
258 static int
__ip_vs_get_out_rt(int skb_af,struct sk_buff * skb,struct ip_vs_dest * dest,__be32 daddr,int rt_mode,__be32 * ret_saddr,struct ip_vs_iphdr * ipvsh)259 __ip_vs_get_out_rt(int skb_af, struct sk_buff *skb, struct ip_vs_dest *dest,
260 __be32 daddr, int rt_mode, __be32 *ret_saddr,
261 struct ip_vs_iphdr *ipvsh)
262 {
263 struct net *net = dev_net(skb_dst(skb)->dev);
264 struct ip_vs_dest_dst *dest_dst;
265 struct rtable *rt; /* Route to the other host */
266 int mtu;
267 int local, noref = 1;
268
269 if (dest) {
270 dest_dst = __ip_vs_dst_check(dest);
271 if (likely(dest_dst))
272 rt = (struct rtable *) dest_dst->dst_cache;
273 else {
274 dest_dst = ip_vs_dest_dst_alloc();
275 spin_lock_bh(&dest->dst_lock);
276 if (!dest_dst) {
277 __ip_vs_dst_set(dest, NULL, NULL, 0);
278 spin_unlock_bh(&dest->dst_lock);
279 goto err_unreach;
280 }
281 rt = do_output_route4(net, dest->addr.ip, rt_mode,
282 &dest_dst->dst_saddr.ip);
283 if (!rt) {
284 __ip_vs_dst_set(dest, NULL, NULL, 0);
285 spin_unlock_bh(&dest->dst_lock);
286 ip_vs_dest_dst_free(dest_dst);
287 goto err_unreach;
288 }
289 __ip_vs_dst_set(dest, dest_dst, &rt->dst, 0);
290 spin_unlock_bh(&dest->dst_lock);
291 IP_VS_DBG(10, "new dst %pI4, src %pI4, refcnt=%d\n",
292 &dest->addr.ip, &dest_dst->dst_saddr.ip,
293 atomic_read(&rt->dst.__refcnt));
294 }
295 if (ret_saddr)
296 *ret_saddr = dest_dst->dst_saddr.ip;
297 } else {
298 __be32 saddr = htonl(INADDR_ANY);
299
300 noref = 0;
301
302 /* For such unconfigured boxes avoid many route lookups
303 * for performance reasons because we do not remember saddr
304 */
305 rt_mode &= ~IP_VS_RT_MODE_CONNECT;
306 rt = do_output_route4(net, daddr, rt_mode, &saddr);
307 if (!rt)
308 goto err_unreach;
309 if (ret_saddr)
310 *ret_saddr = saddr;
311 }
312
313 local = (rt->rt_flags & RTCF_LOCAL) ? 1 : 0;
314 if (unlikely(crosses_local_route_boundary(skb_af, skb, rt_mode,
315 local))) {
316 IP_VS_DBG_RL("We are crossing local and non-local addresses"
317 " daddr=%pI4\n", &daddr);
318 goto err_put;
319 }
320
321 if (unlikely(local)) {
322 /* skb to local stack, preserve old route */
323 if (!noref)
324 ip_rt_put(rt);
325 return local;
326 }
327
328 if (likely(!(rt_mode & IP_VS_RT_MODE_TUNNEL))) {
329 mtu = dst_mtu(&rt->dst);
330 } else {
331 mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
332 if (mtu < 68) {
333 IP_VS_DBG_RL("%s(): mtu less than 68\n", __func__);
334 goto err_put;
335 }
336 maybe_update_pmtu(skb_af, skb, mtu);
337 }
338
339 if (!ensure_mtu_is_adequate(skb_af, rt_mode, ipvsh, skb, mtu))
340 goto err_put;
341
342 skb_dst_drop(skb);
343 if (noref) {
344 if (!local)
345 skb_dst_set_noref(skb, &rt->dst);
346 else
347 skb_dst_set(skb, dst_clone(&rt->dst));
348 } else
349 skb_dst_set(skb, &rt->dst);
350
351 return local;
352
353 err_put:
354 if (!noref)
355 ip_rt_put(rt);
356 return -1;
357
358 err_unreach:
359 dst_link_failure(skb);
360 return -1;
361 }
362
363 #ifdef CONFIG_IP_VS_IPV6
364 static struct dst_entry *
__ip_vs_route_output_v6(struct net * net,struct in6_addr * daddr,struct in6_addr * ret_saddr,int do_xfrm)365 __ip_vs_route_output_v6(struct net *net, struct in6_addr *daddr,
366 struct in6_addr *ret_saddr, int do_xfrm)
367 {
368 struct dst_entry *dst;
369 struct flowi6 fl6 = {
370 .daddr = *daddr,
371 };
372
373 dst = ip6_route_output(net, NULL, &fl6);
374 if (dst->error)
375 goto out_err;
376 if (!ret_saddr)
377 return dst;
378 if (ipv6_addr_any(&fl6.saddr) &&
379 ipv6_dev_get_saddr(net, ip6_dst_idev(dst)->dev,
380 &fl6.daddr, 0, &fl6.saddr) < 0)
381 goto out_err;
382 if (do_xfrm) {
383 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
384 if (IS_ERR(dst)) {
385 dst = NULL;
386 goto out_err;
387 }
388 }
389 *ret_saddr = fl6.saddr;
390 return dst;
391
392 out_err:
393 dst_release(dst);
394 IP_VS_DBG_RL("ip6_route_output error, dest: %pI6\n", daddr);
395 return NULL;
396 }
397
398 /*
399 * Get route to destination or remote server
400 */
401 static int
__ip_vs_get_out_rt_v6(int skb_af,struct sk_buff * skb,struct ip_vs_dest * dest,struct in6_addr * daddr,struct in6_addr * ret_saddr,struct ip_vs_iphdr * ipvsh,int do_xfrm,int rt_mode)402 __ip_vs_get_out_rt_v6(int skb_af, struct sk_buff *skb, struct ip_vs_dest *dest,
403 struct in6_addr *daddr, struct in6_addr *ret_saddr,
404 struct ip_vs_iphdr *ipvsh, int do_xfrm, int rt_mode)
405 {
406 struct net *net = dev_net(skb_dst(skb)->dev);
407 struct ip_vs_dest_dst *dest_dst;
408 struct rt6_info *rt; /* Route to the other host */
409 struct dst_entry *dst;
410 int mtu;
411 int local, noref = 1;
412
413 if (dest) {
414 dest_dst = __ip_vs_dst_check(dest);
415 if (likely(dest_dst))
416 rt = (struct rt6_info *) dest_dst->dst_cache;
417 else {
418 u32 cookie;
419
420 dest_dst = ip_vs_dest_dst_alloc();
421 spin_lock_bh(&dest->dst_lock);
422 if (!dest_dst) {
423 __ip_vs_dst_set(dest, NULL, NULL, 0);
424 spin_unlock_bh(&dest->dst_lock);
425 goto err_unreach;
426 }
427 dst = __ip_vs_route_output_v6(net, &dest->addr.in6,
428 &dest_dst->dst_saddr.in6,
429 do_xfrm);
430 if (!dst) {
431 __ip_vs_dst_set(dest, NULL, NULL, 0);
432 spin_unlock_bh(&dest->dst_lock);
433 ip_vs_dest_dst_free(dest_dst);
434 goto err_unreach;
435 }
436 rt = (struct rt6_info *) dst;
437 cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
438 __ip_vs_dst_set(dest, dest_dst, &rt->dst, cookie);
439 spin_unlock_bh(&dest->dst_lock);
440 IP_VS_DBG(10, "new dst %pI6, src %pI6, refcnt=%d\n",
441 &dest->addr.in6, &dest_dst->dst_saddr.in6,
442 atomic_read(&rt->dst.__refcnt));
443 }
444 if (ret_saddr)
445 *ret_saddr = dest_dst->dst_saddr.in6;
446 } else {
447 noref = 0;
448 dst = __ip_vs_route_output_v6(net, daddr, ret_saddr, do_xfrm);
449 if (!dst)
450 goto err_unreach;
451 rt = (struct rt6_info *) dst;
452 }
453
454 local = __ip_vs_is_local_route6(rt);
455
456 if (unlikely(crosses_local_route_boundary(skb_af, skb, rt_mode,
457 local))) {
458 IP_VS_DBG_RL("We are crossing local and non-local addresses"
459 " daddr=%pI6\n", daddr);
460 goto err_put;
461 }
462
463 if (unlikely(local)) {
464 /* skb to local stack, preserve old route */
465 if (!noref)
466 dst_release(&rt->dst);
467 return local;
468 }
469
470 /* MTU checking */
471 if (likely(!(rt_mode & IP_VS_RT_MODE_TUNNEL)))
472 mtu = dst_mtu(&rt->dst);
473 else {
474 mtu = dst_mtu(&rt->dst) - sizeof(struct ipv6hdr);
475 if (mtu < IPV6_MIN_MTU) {
476 IP_VS_DBG_RL("%s(): mtu less than %d\n", __func__,
477 IPV6_MIN_MTU);
478 goto err_put;
479 }
480 maybe_update_pmtu(skb_af, skb, mtu);
481 }
482
483 if (!ensure_mtu_is_adequate(skb_af, rt_mode, ipvsh, skb, mtu))
484 goto err_put;
485
486 skb_dst_drop(skb);
487 if (noref) {
488 if (!local)
489 skb_dst_set_noref(skb, &rt->dst);
490 else
491 skb_dst_set(skb, dst_clone(&rt->dst));
492 } else
493 skb_dst_set(skb, &rt->dst);
494
495 return local;
496
497 err_put:
498 if (!noref)
499 dst_release(&rt->dst);
500 return -1;
501
502 err_unreach:
503 dst_link_failure(skb);
504 return -1;
505 }
506 #endif
507
508
509 /* return NF_ACCEPT to allow forwarding or other NF_xxx on error */
ip_vs_tunnel_xmit_prepare(struct sk_buff * skb,struct ip_vs_conn * cp)510 static inline int ip_vs_tunnel_xmit_prepare(struct sk_buff *skb,
511 struct ip_vs_conn *cp)
512 {
513 int ret = NF_ACCEPT;
514
515 skb->ipvs_property = 1;
516 if (unlikely(cp->flags & IP_VS_CONN_F_NFCT))
517 ret = ip_vs_confirm_conntrack(skb);
518 if (ret == NF_ACCEPT) {
519 nf_reset(skb);
520 skb_forward_csum(skb);
521 if (!skb->sk)
522 skb_sender_cpu_clear(skb);
523 }
524 return ret;
525 }
526
527 /* In the event of a remote destination, it's possible that we would have
528 * matches against an old socket (particularly a TIME-WAIT socket). This
529 * causes havoc down the line (ip_local_out et. al. expect regular sockets
530 * and invalid memory accesses will happen) so simply drop the association
531 * in this case.
532 */
ip_vs_drop_early_demux_sk(struct sk_buff * skb)533 static inline void ip_vs_drop_early_demux_sk(struct sk_buff *skb)
534 {
535 /* If dev is set, the packet came from the LOCAL_IN callback and
536 * not from a local TCP socket.
537 */
538 if (skb->dev)
539 skb_orphan(skb);
540 }
541
542 /* return NF_STOLEN (sent) or NF_ACCEPT if local=1 (not sent) */
ip_vs_nat_send_or_cont(int pf,struct sk_buff * skb,struct ip_vs_conn * cp,int local)543 static inline int ip_vs_nat_send_or_cont(int pf, struct sk_buff *skb,
544 struct ip_vs_conn *cp, int local)
545 {
546 int ret = NF_STOLEN;
547
548 skb->ipvs_property = 1;
549 if (likely(!(cp->flags & IP_VS_CONN_F_NFCT)))
550 ip_vs_notrack(skb);
551 else
552 ip_vs_update_conntrack(skb, cp, 1);
553
554 /* Remove the early_demux association unless it's bound for the
555 * exact same port and address on this host after translation.
556 */
557 if (!local || cp->vport != cp->dport ||
558 !ip_vs_addr_equal(cp->af, &cp->vaddr, &cp->daddr))
559 ip_vs_drop_early_demux_sk(skb);
560
561 if (!local) {
562 skb_forward_csum(skb);
563 if (!skb->sk)
564 skb_sender_cpu_clear(skb);
565 NF_HOOK(pf, NF_INET_LOCAL_OUT, NULL, skb,
566 NULL, skb_dst(skb)->dev, dst_output_sk);
567 } else
568 ret = NF_ACCEPT;
569
570 return ret;
571 }
572
573 /* return NF_STOLEN (sent) or NF_ACCEPT if local=1 (not sent) */
ip_vs_send_or_cont(int pf,struct sk_buff * skb,struct ip_vs_conn * cp,int local)574 static inline int ip_vs_send_or_cont(int pf, struct sk_buff *skb,
575 struct ip_vs_conn *cp, int local)
576 {
577 int ret = NF_STOLEN;
578
579 skb->ipvs_property = 1;
580 if (likely(!(cp->flags & IP_VS_CONN_F_NFCT)))
581 ip_vs_notrack(skb);
582 if (!local) {
583 ip_vs_drop_early_demux_sk(skb);
584 skb_forward_csum(skb);
585 if (!skb->sk)
586 skb_sender_cpu_clear(skb);
587 NF_HOOK(pf, NF_INET_LOCAL_OUT, NULL, skb,
588 NULL, skb_dst(skb)->dev, dst_output_sk);
589 } else
590 ret = NF_ACCEPT;
591 return ret;
592 }
593
594
595 /*
596 * NULL transmitter (do nothing except return NF_ACCEPT)
597 */
598 int
ip_vs_null_xmit(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)599 ip_vs_null_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
600 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
601 {
602 /* we do not touch skb and do not need pskb ptr */
603 return ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 1);
604 }
605
606
607 /*
608 * Bypass transmitter
609 * Let packets bypass the destination when the destination is not
610 * available, it may be only used in transparent cache cluster.
611 */
612 int
ip_vs_bypass_xmit(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)613 ip_vs_bypass_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
614 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
615 {
616 struct iphdr *iph = ip_hdr(skb);
617
618 EnterFunction(10);
619
620 rcu_read_lock();
621 if (__ip_vs_get_out_rt(cp->af, skb, NULL, iph->daddr,
622 IP_VS_RT_MODE_NON_LOCAL, NULL, ipvsh) < 0)
623 goto tx_error;
624
625 ip_send_check(iph);
626
627 /* Another hack: avoid icmp_send in ip_fragment */
628 skb->ignore_df = 1;
629
630 ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 0);
631 rcu_read_unlock();
632
633 LeaveFunction(10);
634 return NF_STOLEN;
635
636 tx_error:
637 kfree_skb(skb);
638 rcu_read_unlock();
639 LeaveFunction(10);
640 return NF_STOLEN;
641 }
642
643 #ifdef CONFIG_IP_VS_IPV6
644 int
ip_vs_bypass_xmit_v6(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)645 ip_vs_bypass_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
646 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
647 {
648 EnterFunction(10);
649
650 rcu_read_lock();
651 if (__ip_vs_get_out_rt_v6(cp->af, skb, NULL, &ipvsh->daddr.in6, NULL,
652 ipvsh, 0, IP_VS_RT_MODE_NON_LOCAL) < 0)
653 goto tx_error;
654
655 /* Another hack: avoid icmp_send in ip_fragment */
656 skb->ignore_df = 1;
657
658 ip_vs_send_or_cont(NFPROTO_IPV6, skb, cp, 0);
659 rcu_read_unlock();
660
661 LeaveFunction(10);
662 return NF_STOLEN;
663
664 tx_error:
665 kfree_skb(skb);
666 rcu_read_unlock();
667 LeaveFunction(10);
668 return NF_STOLEN;
669 }
670 #endif
671
672 /*
673 * NAT transmitter (only for outside-to-inside nat forwarding)
674 * Not used for related ICMP
675 */
676 int
ip_vs_nat_xmit(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)677 ip_vs_nat_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
678 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
679 {
680 struct rtable *rt; /* Route to the other host */
681 int local, rc, was_input;
682
683 EnterFunction(10);
684
685 rcu_read_lock();
686 /* check if it is a connection of no-client-port */
687 if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT)) {
688 __be16 _pt, *p;
689
690 p = skb_header_pointer(skb, ipvsh->len, sizeof(_pt), &_pt);
691 if (p == NULL)
692 goto tx_error;
693 ip_vs_conn_fill_cport(cp, *p);
694 IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
695 }
696
697 was_input = rt_is_input_route(skb_rtable(skb));
698 local = __ip_vs_get_out_rt(cp->af, skb, cp->dest, cp->daddr.ip,
699 IP_VS_RT_MODE_LOCAL |
700 IP_VS_RT_MODE_NON_LOCAL |
701 IP_VS_RT_MODE_RDR, NULL, ipvsh);
702 if (local < 0)
703 goto tx_error;
704 rt = skb_rtable(skb);
705 /*
706 * Avoid duplicate tuple in reply direction for NAT traffic
707 * to local address when connection is sync-ed
708 */
709 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
710 if (cp->flags & IP_VS_CONN_F_SYNC && local) {
711 enum ip_conntrack_info ctinfo;
712 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
713
714 if (ct && !nf_ct_is_untracked(ct)) {
715 IP_VS_DBG_RL_PKT(10, AF_INET, pp, skb, 0,
716 "ip_vs_nat_xmit(): "
717 "stopping DNAT to local address");
718 goto tx_error;
719 }
720 }
721 #endif
722
723 /* From world but DNAT to loopback address? */
724 if (local && ipv4_is_loopback(cp->daddr.ip) && was_input) {
725 IP_VS_DBG_RL_PKT(1, AF_INET, pp, skb, 0, "ip_vs_nat_xmit(): "
726 "stopping DNAT to loopback address");
727 goto tx_error;
728 }
729
730 /* copy-on-write the packet before mangling it */
731 if (!skb_make_writable(skb, sizeof(struct iphdr)))
732 goto tx_error;
733
734 if (skb_cow(skb, rt->dst.dev->hard_header_len))
735 goto tx_error;
736
737 /* mangle the packet */
738 if (pp->dnat_handler && !pp->dnat_handler(skb, pp, cp, ipvsh))
739 goto tx_error;
740 ip_hdr(skb)->daddr = cp->daddr.ip;
741 ip_send_check(ip_hdr(skb));
742
743 IP_VS_DBG_PKT(10, AF_INET, pp, skb, 0, "After DNAT");
744
745 /* FIXME: when application helper enlarges the packet and the length
746 is larger than the MTU of outgoing device, there will be still
747 MTU problem. */
748
749 /* Another hack: avoid icmp_send in ip_fragment */
750 skb->ignore_df = 1;
751
752 rc = ip_vs_nat_send_or_cont(NFPROTO_IPV4, skb, cp, local);
753 rcu_read_unlock();
754
755 LeaveFunction(10);
756 return rc;
757
758 tx_error:
759 kfree_skb(skb);
760 rcu_read_unlock();
761 LeaveFunction(10);
762 return NF_STOLEN;
763 }
764
765 #ifdef CONFIG_IP_VS_IPV6
766 int
ip_vs_nat_xmit_v6(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)767 ip_vs_nat_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
768 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
769 {
770 struct rt6_info *rt; /* Route to the other host */
771 int local, rc;
772
773 EnterFunction(10);
774
775 rcu_read_lock();
776 /* check if it is a connection of no-client-port */
777 if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT && !ipvsh->fragoffs)) {
778 __be16 _pt, *p;
779 p = skb_header_pointer(skb, ipvsh->len, sizeof(_pt), &_pt);
780 if (p == NULL)
781 goto tx_error;
782 ip_vs_conn_fill_cport(cp, *p);
783 IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
784 }
785
786 local = __ip_vs_get_out_rt_v6(cp->af, skb, cp->dest, &cp->daddr.in6,
787 NULL, ipvsh, 0,
788 IP_VS_RT_MODE_LOCAL |
789 IP_VS_RT_MODE_NON_LOCAL |
790 IP_VS_RT_MODE_RDR);
791 if (local < 0)
792 goto tx_error;
793 rt = (struct rt6_info *) skb_dst(skb);
794 /*
795 * Avoid duplicate tuple in reply direction for NAT traffic
796 * to local address when connection is sync-ed
797 */
798 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
799 if (cp->flags & IP_VS_CONN_F_SYNC && local) {
800 enum ip_conntrack_info ctinfo;
801 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
802
803 if (ct && !nf_ct_is_untracked(ct)) {
804 IP_VS_DBG_RL_PKT(10, AF_INET6, pp, skb, 0,
805 "ip_vs_nat_xmit_v6(): "
806 "stopping DNAT to local address");
807 goto tx_error;
808 }
809 }
810 #endif
811
812 /* From world but DNAT to loopback address? */
813 if (local && skb->dev && !(skb->dev->flags & IFF_LOOPBACK) &&
814 ipv6_addr_type(&rt->rt6i_dst.addr) & IPV6_ADDR_LOOPBACK) {
815 IP_VS_DBG_RL_PKT(1, AF_INET6, pp, skb, 0,
816 "ip_vs_nat_xmit_v6(): "
817 "stopping DNAT to loopback address");
818 goto tx_error;
819 }
820
821 /* copy-on-write the packet before mangling it */
822 if (!skb_make_writable(skb, sizeof(struct ipv6hdr)))
823 goto tx_error;
824
825 if (skb_cow(skb, rt->dst.dev->hard_header_len))
826 goto tx_error;
827
828 /* mangle the packet */
829 if (pp->dnat_handler && !pp->dnat_handler(skb, pp, cp, ipvsh))
830 goto tx_error;
831 ipv6_hdr(skb)->daddr = cp->daddr.in6;
832
833 IP_VS_DBG_PKT(10, AF_INET6, pp, skb, 0, "After DNAT");
834
835 /* FIXME: when application helper enlarges the packet and the length
836 is larger than the MTU of outgoing device, there will be still
837 MTU problem. */
838
839 /* Another hack: avoid icmp_send in ip_fragment */
840 skb->ignore_df = 1;
841
842 rc = ip_vs_nat_send_or_cont(NFPROTO_IPV6, skb, cp, local);
843 rcu_read_unlock();
844
845 LeaveFunction(10);
846 return rc;
847
848 tx_error:
849 LeaveFunction(10);
850 kfree_skb(skb);
851 rcu_read_unlock();
852 return NF_STOLEN;
853 }
854 #endif
855
856 /* When forwarding a packet, we must ensure that we've got enough headroom
857 * for the encapsulation packet in the skb. This also gives us an
858 * opportunity to figure out what the payload_len, dsfield, ttl, and df
859 * values should be, so that we won't need to look at the old ip header
860 * again
861 */
862 static struct sk_buff *
ip_vs_prepare_tunneled_skb(struct sk_buff * skb,int skb_af,unsigned int max_headroom,__u8 * next_protocol,__u32 * payload_len,__u8 * dsfield,__u8 * ttl,__be16 * df)863 ip_vs_prepare_tunneled_skb(struct sk_buff *skb, int skb_af,
864 unsigned int max_headroom, __u8 *next_protocol,
865 __u32 *payload_len, __u8 *dsfield, __u8 *ttl,
866 __be16 *df)
867 {
868 struct sk_buff *new_skb = NULL;
869 struct iphdr *old_iph = NULL;
870 #ifdef CONFIG_IP_VS_IPV6
871 struct ipv6hdr *old_ipv6h = NULL;
872 #endif
873
874 ip_vs_drop_early_demux_sk(skb);
875
876 if (skb_headroom(skb) < max_headroom || skb_cloned(skb)) {
877 new_skb = skb_realloc_headroom(skb, max_headroom);
878 if (!new_skb)
879 goto error;
880 if (skb->sk)
881 skb_set_owner_w(new_skb, skb->sk);
882 consume_skb(skb);
883 skb = new_skb;
884 }
885
886 #ifdef CONFIG_IP_VS_IPV6
887 if (skb_af == AF_INET6) {
888 old_ipv6h = ipv6_hdr(skb);
889 *next_protocol = IPPROTO_IPV6;
890 if (payload_len)
891 *payload_len =
892 ntohs(old_ipv6h->payload_len) +
893 sizeof(*old_ipv6h);
894 *dsfield = ipv6_get_dsfield(old_ipv6h);
895 *ttl = old_ipv6h->hop_limit;
896 if (df)
897 *df = 0;
898 } else
899 #endif
900 {
901 old_iph = ip_hdr(skb);
902 /* Copy DF, reset fragment offset and MF */
903 if (df)
904 *df = (old_iph->frag_off & htons(IP_DF));
905 *next_protocol = IPPROTO_IPIP;
906
907 /* fix old IP header checksum */
908 ip_send_check(old_iph);
909 *dsfield = ipv4_get_dsfield(old_iph);
910 *ttl = old_iph->ttl;
911 if (payload_len)
912 *payload_len = ntohs(old_iph->tot_len);
913 }
914
915 return skb;
916 error:
917 kfree_skb(skb);
918 return ERR_PTR(-ENOMEM);
919 }
920
__tun_gso_type_mask(int encaps_af,int orig_af)921 static inline int __tun_gso_type_mask(int encaps_af, int orig_af)
922 {
923 if (encaps_af == AF_INET) {
924 if (orig_af == AF_INET)
925 return SKB_GSO_IPIP;
926
927 return SKB_GSO_SIT;
928 }
929
930 /* GSO: we need to provide proper SKB_GSO_ value for IPv6:
931 * SKB_GSO_SIT/IPV6
932 */
933 return 0;
934 }
935
936 /*
937 * IP Tunneling transmitter
938 *
939 * This function encapsulates the packet in a new IP packet, its
940 * destination will be set to cp->daddr. Most code of this function
941 * is taken from ipip.c.
942 *
943 * It is used in VS/TUN cluster. The load balancer selects a real
944 * server from a cluster based on a scheduling algorithm,
945 * encapsulates the request packet and forwards it to the selected
946 * server. For example, all real servers are configured with
947 * "ifconfig tunl0 <Virtual IP Address> up". When the server receives
948 * the encapsulated packet, it will decapsulate the packet, processe
949 * the request and return the response packets directly to the client
950 * without passing the load balancer. This can greatly increase the
951 * scalability of virtual server.
952 *
953 * Used for ANY protocol
954 */
955 int
ip_vs_tunnel_xmit(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)956 ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
957 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
958 {
959 struct net *net = skb_net(skb);
960 struct netns_ipvs *ipvs = net_ipvs(net);
961 struct rtable *rt; /* Route to the other host */
962 __be32 saddr; /* Source for tunnel */
963 struct net_device *tdev; /* Device to other host */
964 __u8 next_protocol = 0;
965 __u8 dsfield = 0;
966 __u8 ttl = 0;
967 __be16 df = 0;
968 __be16 *dfp = NULL;
969 struct iphdr *iph; /* Our new IP header */
970 unsigned int max_headroom; /* The extra header space needed */
971 int ret, local;
972
973 EnterFunction(10);
974
975 rcu_read_lock();
976 local = __ip_vs_get_out_rt(cp->af, skb, cp->dest, cp->daddr.ip,
977 IP_VS_RT_MODE_LOCAL |
978 IP_VS_RT_MODE_NON_LOCAL |
979 IP_VS_RT_MODE_CONNECT |
980 IP_VS_RT_MODE_TUNNEL, &saddr, ipvsh);
981 if (local < 0)
982 goto tx_error;
983 if (local) {
984 rcu_read_unlock();
985 return ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 1);
986 }
987
988 rt = skb_rtable(skb);
989 tdev = rt->dst.dev;
990
991 /*
992 * Okay, now see if we can stuff it in the buffer as-is.
993 */
994 max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct iphdr);
995
996 /* We only care about the df field if sysctl_pmtu_disc(ipvs) is set */
997 dfp = sysctl_pmtu_disc(ipvs) ? &df : NULL;
998 skb = ip_vs_prepare_tunneled_skb(skb, cp->af, max_headroom,
999 &next_protocol, NULL, &dsfield,
1000 &ttl, dfp);
1001 if (IS_ERR(skb))
1002 goto tx_error;
1003
1004 skb = iptunnel_handle_offloads(
1005 skb, false, __tun_gso_type_mask(AF_INET, cp->af));
1006 if (IS_ERR(skb))
1007 goto tx_error;
1008
1009 skb->transport_header = skb->network_header;
1010
1011 skb_push(skb, sizeof(struct iphdr));
1012 skb_reset_network_header(skb);
1013 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1014
1015 /*
1016 * Push down and install the IPIP header.
1017 */
1018 iph = ip_hdr(skb);
1019 iph->version = 4;
1020 iph->ihl = sizeof(struct iphdr)>>2;
1021 iph->frag_off = df;
1022 iph->protocol = next_protocol;
1023 iph->tos = dsfield;
1024 iph->daddr = cp->daddr.ip;
1025 iph->saddr = saddr;
1026 iph->ttl = ttl;
1027 ip_select_ident(net, skb, NULL);
1028
1029 /* Another hack: avoid icmp_send in ip_fragment */
1030 skb->ignore_df = 1;
1031
1032 ret = ip_vs_tunnel_xmit_prepare(skb, cp);
1033 if (ret == NF_ACCEPT)
1034 ip_local_out(skb);
1035 else if (ret == NF_DROP)
1036 kfree_skb(skb);
1037 rcu_read_unlock();
1038
1039 LeaveFunction(10);
1040
1041 return NF_STOLEN;
1042
1043 tx_error:
1044 if (!IS_ERR(skb))
1045 kfree_skb(skb);
1046 rcu_read_unlock();
1047 LeaveFunction(10);
1048 return NF_STOLEN;
1049 }
1050
1051 #ifdef CONFIG_IP_VS_IPV6
1052 int
ip_vs_tunnel_xmit_v6(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)1053 ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
1054 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
1055 {
1056 struct rt6_info *rt; /* Route to the other host */
1057 struct in6_addr saddr; /* Source for tunnel */
1058 struct net_device *tdev; /* Device to other host */
1059 __u8 next_protocol = 0;
1060 __u32 payload_len = 0;
1061 __u8 dsfield = 0;
1062 __u8 ttl = 0;
1063 struct ipv6hdr *iph; /* Our new IP header */
1064 unsigned int max_headroom; /* The extra header space needed */
1065 int ret, local;
1066
1067 EnterFunction(10);
1068
1069 rcu_read_lock();
1070 local = __ip_vs_get_out_rt_v6(cp->af, skb, cp->dest, &cp->daddr.in6,
1071 &saddr, ipvsh, 1,
1072 IP_VS_RT_MODE_LOCAL |
1073 IP_VS_RT_MODE_NON_LOCAL |
1074 IP_VS_RT_MODE_TUNNEL);
1075 if (local < 0)
1076 goto tx_error;
1077 if (local) {
1078 rcu_read_unlock();
1079 return ip_vs_send_or_cont(NFPROTO_IPV6, skb, cp, 1);
1080 }
1081
1082 rt = (struct rt6_info *) skb_dst(skb);
1083 tdev = rt->dst.dev;
1084
1085 /*
1086 * Okay, now see if we can stuff it in the buffer as-is.
1087 */
1088 max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct ipv6hdr);
1089
1090 skb = ip_vs_prepare_tunneled_skb(skb, cp->af, max_headroom,
1091 &next_protocol, &payload_len,
1092 &dsfield, &ttl, NULL);
1093 if (IS_ERR(skb))
1094 goto tx_error;
1095
1096 skb = iptunnel_handle_offloads(
1097 skb, false, __tun_gso_type_mask(AF_INET6, cp->af));
1098 if (IS_ERR(skb))
1099 goto tx_error;
1100
1101 skb->transport_header = skb->network_header;
1102
1103 skb_push(skb, sizeof(struct ipv6hdr));
1104 skb_reset_network_header(skb);
1105 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1106
1107 /*
1108 * Push down and install the IPIP header.
1109 */
1110 iph = ipv6_hdr(skb);
1111 iph->version = 6;
1112 iph->nexthdr = next_protocol;
1113 iph->payload_len = htons(payload_len);
1114 memset(&iph->flow_lbl, 0, sizeof(iph->flow_lbl));
1115 ipv6_change_dsfield(iph, 0, dsfield);
1116 iph->daddr = cp->daddr.in6;
1117 iph->saddr = saddr;
1118 iph->hop_limit = ttl;
1119
1120 /* Another hack: avoid icmp_send in ip_fragment */
1121 skb->ignore_df = 1;
1122
1123 ret = ip_vs_tunnel_xmit_prepare(skb, cp);
1124 if (ret == NF_ACCEPT)
1125 ip6_local_out(skb);
1126 else if (ret == NF_DROP)
1127 kfree_skb(skb);
1128 rcu_read_unlock();
1129
1130 LeaveFunction(10);
1131
1132 return NF_STOLEN;
1133
1134 tx_error:
1135 if (!IS_ERR(skb))
1136 kfree_skb(skb);
1137 rcu_read_unlock();
1138 LeaveFunction(10);
1139 return NF_STOLEN;
1140 }
1141 #endif
1142
1143
1144 /*
1145 * Direct Routing transmitter
1146 * Used for ANY protocol
1147 */
1148 int
ip_vs_dr_xmit(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)1149 ip_vs_dr_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
1150 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
1151 {
1152 int local;
1153
1154 EnterFunction(10);
1155
1156 rcu_read_lock();
1157 local = __ip_vs_get_out_rt(cp->af, skb, cp->dest, cp->daddr.ip,
1158 IP_VS_RT_MODE_LOCAL |
1159 IP_VS_RT_MODE_NON_LOCAL |
1160 IP_VS_RT_MODE_KNOWN_NH, NULL, ipvsh);
1161 if (local < 0)
1162 goto tx_error;
1163 if (local) {
1164 rcu_read_unlock();
1165 return ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 1);
1166 }
1167
1168 ip_send_check(ip_hdr(skb));
1169
1170 /* Another hack: avoid icmp_send in ip_fragment */
1171 skb->ignore_df = 1;
1172
1173 ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 0);
1174 rcu_read_unlock();
1175
1176 LeaveFunction(10);
1177 return NF_STOLEN;
1178
1179 tx_error:
1180 kfree_skb(skb);
1181 rcu_read_unlock();
1182 LeaveFunction(10);
1183 return NF_STOLEN;
1184 }
1185
1186 #ifdef CONFIG_IP_VS_IPV6
1187 int
ip_vs_dr_xmit_v6(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)1188 ip_vs_dr_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
1189 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
1190 {
1191 int local;
1192
1193 EnterFunction(10);
1194
1195 rcu_read_lock();
1196 local = __ip_vs_get_out_rt_v6(cp->af, skb, cp->dest, &cp->daddr.in6,
1197 NULL, ipvsh, 0,
1198 IP_VS_RT_MODE_LOCAL |
1199 IP_VS_RT_MODE_NON_LOCAL);
1200 if (local < 0)
1201 goto tx_error;
1202 if (local) {
1203 rcu_read_unlock();
1204 return ip_vs_send_or_cont(NFPROTO_IPV6, skb, cp, 1);
1205 }
1206
1207 /* Another hack: avoid icmp_send in ip_fragment */
1208 skb->ignore_df = 1;
1209
1210 ip_vs_send_or_cont(NFPROTO_IPV6, skb, cp, 0);
1211 rcu_read_unlock();
1212
1213 LeaveFunction(10);
1214 return NF_STOLEN;
1215
1216 tx_error:
1217 kfree_skb(skb);
1218 rcu_read_unlock();
1219 LeaveFunction(10);
1220 return NF_STOLEN;
1221 }
1222 #endif
1223
1224
1225 /*
1226 * ICMP packet transmitter
1227 * called by the ip_vs_in_icmp
1228 */
1229 int
ip_vs_icmp_xmit(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,int offset,unsigned int hooknum,struct ip_vs_iphdr * iph)1230 ip_vs_icmp_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
1231 struct ip_vs_protocol *pp, int offset, unsigned int hooknum,
1232 struct ip_vs_iphdr *iph)
1233 {
1234 struct rtable *rt; /* Route to the other host */
1235 int rc;
1236 int local;
1237 int rt_mode, was_input;
1238
1239 EnterFunction(10);
1240
1241 /* The ICMP packet for VS/TUN, VS/DR and LOCALNODE will be
1242 forwarded directly here, because there is no need to
1243 translate address/port back */
1244 if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ) {
1245 if (cp->packet_xmit)
1246 rc = cp->packet_xmit(skb, cp, pp, iph);
1247 else
1248 rc = NF_ACCEPT;
1249 /* do not touch skb anymore */
1250 atomic_inc(&cp->in_pkts);
1251 goto out;
1252 }
1253
1254 /*
1255 * mangle and send the packet here (only for VS/NAT)
1256 */
1257 was_input = rt_is_input_route(skb_rtable(skb));
1258
1259 /* LOCALNODE from FORWARD hook is not supported */
1260 rt_mode = (hooknum != NF_INET_FORWARD) ?
1261 IP_VS_RT_MODE_LOCAL | IP_VS_RT_MODE_NON_LOCAL |
1262 IP_VS_RT_MODE_RDR : IP_VS_RT_MODE_NON_LOCAL;
1263 rcu_read_lock();
1264 local = __ip_vs_get_out_rt(cp->af, skb, cp->dest, cp->daddr.ip, rt_mode,
1265 NULL, iph);
1266 if (local < 0)
1267 goto tx_error;
1268 rt = skb_rtable(skb);
1269
1270 /*
1271 * Avoid duplicate tuple in reply direction for NAT traffic
1272 * to local address when connection is sync-ed
1273 */
1274 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
1275 if (cp->flags & IP_VS_CONN_F_SYNC && local) {
1276 enum ip_conntrack_info ctinfo;
1277 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
1278
1279 if (ct && !nf_ct_is_untracked(ct)) {
1280 IP_VS_DBG(10, "%s(): "
1281 "stopping DNAT to local address %pI4\n",
1282 __func__, &cp->daddr.ip);
1283 goto tx_error;
1284 }
1285 }
1286 #endif
1287
1288 /* From world but DNAT to loopback address? */
1289 if (local && ipv4_is_loopback(cp->daddr.ip) && was_input) {
1290 IP_VS_DBG(1, "%s(): "
1291 "stopping DNAT to loopback %pI4\n",
1292 __func__, &cp->daddr.ip);
1293 goto tx_error;
1294 }
1295
1296 /* copy-on-write the packet before mangling it */
1297 if (!skb_make_writable(skb, offset))
1298 goto tx_error;
1299
1300 if (skb_cow(skb, rt->dst.dev->hard_header_len))
1301 goto tx_error;
1302
1303 ip_vs_nat_icmp(skb, pp, cp, 0);
1304
1305 /* Another hack: avoid icmp_send in ip_fragment */
1306 skb->ignore_df = 1;
1307
1308 rc = ip_vs_nat_send_or_cont(NFPROTO_IPV4, skb, cp, local);
1309 rcu_read_unlock();
1310 goto out;
1311
1312 tx_error:
1313 kfree_skb(skb);
1314 rcu_read_unlock();
1315 rc = NF_STOLEN;
1316 out:
1317 LeaveFunction(10);
1318 return rc;
1319 }
1320
1321 #ifdef CONFIG_IP_VS_IPV6
1322 int
ip_vs_icmp_xmit_v6(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,int offset,unsigned int hooknum,struct ip_vs_iphdr * ipvsh)1323 ip_vs_icmp_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
1324 struct ip_vs_protocol *pp, int offset, unsigned int hooknum,
1325 struct ip_vs_iphdr *ipvsh)
1326 {
1327 struct rt6_info *rt; /* Route to the other host */
1328 int rc;
1329 int local;
1330 int rt_mode;
1331
1332 EnterFunction(10);
1333
1334 /* The ICMP packet for VS/TUN, VS/DR and LOCALNODE will be
1335 forwarded directly here, because there is no need to
1336 translate address/port back */
1337 if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ) {
1338 if (cp->packet_xmit)
1339 rc = cp->packet_xmit(skb, cp, pp, ipvsh);
1340 else
1341 rc = NF_ACCEPT;
1342 /* do not touch skb anymore */
1343 atomic_inc(&cp->in_pkts);
1344 goto out;
1345 }
1346
1347 /*
1348 * mangle and send the packet here (only for VS/NAT)
1349 */
1350
1351 /* LOCALNODE from FORWARD hook is not supported */
1352 rt_mode = (hooknum != NF_INET_FORWARD) ?
1353 IP_VS_RT_MODE_LOCAL | IP_VS_RT_MODE_NON_LOCAL |
1354 IP_VS_RT_MODE_RDR : IP_VS_RT_MODE_NON_LOCAL;
1355 rcu_read_lock();
1356 local = __ip_vs_get_out_rt_v6(cp->af, skb, cp->dest, &cp->daddr.in6,
1357 NULL, ipvsh, 0, rt_mode);
1358 if (local < 0)
1359 goto tx_error;
1360 rt = (struct rt6_info *) skb_dst(skb);
1361 /*
1362 * Avoid duplicate tuple in reply direction for NAT traffic
1363 * to local address when connection is sync-ed
1364 */
1365 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
1366 if (cp->flags & IP_VS_CONN_F_SYNC && local) {
1367 enum ip_conntrack_info ctinfo;
1368 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
1369
1370 if (ct && !nf_ct_is_untracked(ct)) {
1371 IP_VS_DBG(10, "%s(): "
1372 "stopping DNAT to local address %pI6\n",
1373 __func__, &cp->daddr.in6);
1374 goto tx_error;
1375 }
1376 }
1377 #endif
1378
1379 /* From world but DNAT to loopback address? */
1380 if (local && skb->dev && !(skb->dev->flags & IFF_LOOPBACK) &&
1381 ipv6_addr_type(&rt->rt6i_dst.addr) & IPV6_ADDR_LOOPBACK) {
1382 IP_VS_DBG(1, "%s(): "
1383 "stopping DNAT to loopback %pI6\n",
1384 __func__, &cp->daddr.in6);
1385 goto tx_error;
1386 }
1387
1388 /* copy-on-write the packet before mangling it */
1389 if (!skb_make_writable(skb, offset))
1390 goto tx_error;
1391
1392 if (skb_cow(skb, rt->dst.dev->hard_header_len))
1393 goto tx_error;
1394
1395 ip_vs_nat_icmp_v6(skb, pp, cp, 0);
1396
1397 /* Another hack: avoid icmp_send in ip_fragment */
1398 skb->ignore_df = 1;
1399
1400 rc = ip_vs_nat_send_or_cont(NFPROTO_IPV6, skb, cp, local);
1401 rcu_read_unlock();
1402 goto out;
1403
1404 tx_error:
1405 kfree_skb(skb);
1406 rcu_read_unlock();
1407 rc = NF_STOLEN;
1408 out:
1409 LeaveFunction(10);
1410 return rc;
1411 }
1412 #endif
1413