1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * ip_vs_xmit.c: various packet transmitters for IPVS
4 *
5 * Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
6 * Julian Anastasov <ja@ssi.bg>
7 *
8 * Changes:
9 *
10 * Description of forwarding methods:
11 * - all transmitters are called from LOCAL_IN (remote clients) and
12 * LOCAL_OUT (local clients) but for ICMP can be called from FORWARD
13 * - not all connections have destination server, for example,
14 * connections in backup server when fwmark is used
15 * - bypass connections use daddr from packet
16 * - we can use dst without ref while sending in RCU section, we use
17 * ref when returning NF_ACCEPT for NAT-ed packet via loopback
18 * LOCAL_OUT rules:
19 * - skb->dev is NULL, skb->protocol is not set (both are set in POST_ROUTING)
20 * - skb->pkt_type is not set yet
21 * - the only place where we can see skb->sk != NULL
22 */
23
24 #define KMSG_COMPONENT "IPVS"
25 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
26
27 #include <linux/kernel.h>
28 #include <linux/slab.h>
29 #include <linux/tcp.h> /* for tcphdr */
30 #include <net/ip.h>
31 #include <net/gue.h>
32 #include <net/gre.h>
33 #include <net/tcp.h> /* for csum_tcpudp_magic */
34 #include <net/udp.h>
35 #include <net/icmp.h> /* for icmp_send */
36 #include <net/route.h> /* for ip_route_output */
37 #include <net/ipv6.h>
38 #include <net/ip6_route.h>
39 #include <net/ip_tunnels.h>
40 #include <net/ip6_checksum.h>
41 #include <net/addrconf.h>
42 #include <linux/icmpv6.h>
43 #include <linux/netfilter.h>
44 #include <linux/netfilter_ipv4.h>
45
46 #include <net/ip_vs.h>
47
48 enum {
49 IP_VS_RT_MODE_LOCAL = 1, /* Allow local dest */
50 IP_VS_RT_MODE_NON_LOCAL = 2, /* Allow non-local dest */
51 IP_VS_RT_MODE_RDR = 4, /* Allow redirect from remote daddr to
52 * local
53 */
54 IP_VS_RT_MODE_CONNECT = 8, /* Always bind route to saddr */
55 IP_VS_RT_MODE_KNOWN_NH = 16,/* Route via remote addr */
56 IP_VS_RT_MODE_TUNNEL = 32,/* Tunnel mode */
57 };
58
ip_vs_dest_dst_alloc(void)59 static inline struct ip_vs_dest_dst *ip_vs_dest_dst_alloc(void)
60 {
61 return kmalloc(sizeof(struct ip_vs_dest_dst), GFP_ATOMIC);
62 }
63
ip_vs_dest_dst_free(struct ip_vs_dest_dst * dest_dst)64 static inline void ip_vs_dest_dst_free(struct ip_vs_dest_dst *dest_dst)
65 {
66 kfree(dest_dst);
67 }
68
69 /*
70 * Destination cache to speed up outgoing route lookup
71 */
72 static inline void
__ip_vs_dst_set(struct ip_vs_dest * dest,struct ip_vs_dest_dst * dest_dst,struct dst_entry * dst,u32 dst_cookie)73 __ip_vs_dst_set(struct ip_vs_dest *dest, struct ip_vs_dest_dst *dest_dst,
74 struct dst_entry *dst, u32 dst_cookie)
75 {
76 struct ip_vs_dest_dst *old;
77
78 old = rcu_dereference_protected(dest->dest_dst,
79 lockdep_is_held(&dest->dst_lock));
80
81 if (dest_dst) {
82 dest_dst->dst_cache = dst;
83 dest_dst->dst_cookie = dst_cookie;
84 }
85 rcu_assign_pointer(dest->dest_dst, dest_dst);
86
87 if (old)
88 call_rcu(&old->rcu_head, ip_vs_dest_dst_rcu_free);
89 }
90
91 static inline struct ip_vs_dest_dst *
__ip_vs_dst_check(struct ip_vs_dest * dest)92 __ip_vs_dst_check(struct ip_vs_dest *dest)
93 {
94 struct ip_vs_dest_dst *dest_dst = rcu_dereference(dest->dest_dst);
95 struct dst_entry *dst;
96
97 if (!dest_dst)
98 return NULL;
99 dst = dest_dst->dst_cache;
100 if (dst->obsolete &&
101 dst->ops->check(dst, dest_dst->dst_cookie) == NULL)
102 return NULL;
103 return dest_dst;
104 }
105
106 static inline bool
__mtu_check_toobig_v6(const struct sk_buff * skb,u32 mtu)107 __mtu_check_toobig_v6(const struct sk_buff *skb, u32 mtu)
108 {
109 if (IP6CB(skb)->frag_max_size) {
110 /* frag_max_size tell us that, this packet have been
111 * defragmented by netfilter IPv6 conntrack module.
112 */
113 if (IP6CB(skb)->frag_max_size > mtu)
114 return true; /* largest fragment violate MTU */
115 }
116 else if (skb->len > mtu && !skb_is_gso(skb)) {
117 return true; /* Packet size violate MTU size */
118 }
119 return false;
120 }
121
122 /* Get route to daddr, update *saddr, optionally bind route to saddr */
do_output_route4(struct net * net,__be32 daddr,int rt_mode,__be32 * saddr)123 static struct rtable *do_output_route4(struct net *net, __be32 daddr,
124 int rt_mode, __be32 *saddr)
125 {
126 struct flowi4 fl4;
127 struct rtable *rt;
128 bool loop = false;
129
130 memset(&fl4, 0, sizeof(fl4));
131 fl4.daddr = daddr;
132 fl4.flowi4_flags = (rt_mode & IP_VS_RT_MODE_KNOWN_NH) ?
133 FLOWI_FLAG_KNOWN_NH : 0;
134
135 retry:
136 rt = ip_route_output_key(net, &fl4);
137 if (IS_ERR(rt)) {
138 /* Invalid saddr ? */
139 if (PTR_ERR(rt) == -EINVAL && *saddr &&
140 rt_mode & IP_VS_RT_MODE_CONNECT && !loop) {
141 *saddr = 0;
142 flowi4_update_output(&fl4, 0, 0, daddr, 0);
143 goto retry;
144 }
145 IP_VS_DBG_RL("ip_route_output error, dest: %pI4\n", &daddr);
146 return NULL;
147 } else if (!*saddr && rt_mode & IP_VS_RT_MODE_CONNECT && fl4.saddr) {
148 ip_rt_put(rt);
149 *saddr = fl4.saddr;
150 flowi4_update_output(&fl4, 0, 0, daddr, fl4.saddr);
151 loop = true;
152 goto retry;
153 }
154 *saddr = fl4.saddr;
155 return rt;
156 }
157
158 #ifdef CONFIG_IP_VS_IPV6
__ip_vs_is_local_route6(struct rt6_info * rt)159 static inline int __ip_vs_is_local_route6(struct rt6_info *rt)
160 {
161 return rt->dst.dev && rt->dst.dev->flags & IFF_LOOPBACK;
162 }
163 #endif
164
crosses_local_route_boundary(int skb_af,struct sk_buff * skb,int rt_mode,bool new_rt_is_local)165 static inline bool crosses_local_route_boundary(int skb_af, struct sk_buff *skb,
166 int rt_mode,
167 bool new_rt_is_local)
168 {
169 bool rt_mode_allow_local = !!(rt_mode & IP_VS_RT_MODE_LOCAL);
170 bool rt_mode_allow_non_local = !!(rt_mode & IP_VS_RT_MODE_NON_LOCAL);
171 bool rt_mode_allow_redirect = !!(rt_mode & IP_VS_RT_MODE_RDR);
172 bool source_is_loopback;
173 bool old_rt_is_local;
174
175 #ifdef CONFIG_IP_VS_IPV6
176 if (skb_af == AF_INET6) {
177 int addr_type = ipv6_addr_type(&ipv6_hdr(skb)->saddr);
178
179 source_is_loopback =
180 (!skb->dev || skb->dev->flags & IFF_LOOPBACK) &&
181 (addr_type & IPV6_ADDR_LOOPBACK);
182 old_rt_is_local = __ip_vs_is_local_route6(
183 (struct rt6_info *)skb_dst(skb));
184 } else
185 #endif
186 {
187 source_is_loopback = ipv4_is_loopback(ip_hdr(skb)->saddr);
188 old_rt_is_local = skb_rtable(skb)->rt_flags & RTCF_LOCAL;
189 }
190
191 if (unlikely(new_rt_is_local)) {
192 if (!rt_mode_allow_local)
193 return true;
194 if (!rt_mode_allow_redirect && !old_rt_is_local)
195 return true;
196 } else {
197 if (!rt_mode_allow_non_local)
198 return true;
199 if (source_is_loopback)
200 return true;
201 }
202 return false;
203 }
204
maybe_update_pmtu(int skb_af,struct sk_buff * skb,int mtu)205 static inline void maybe_update_pmtu(int skb_af, struct sk_buff *skb, int mtu)
206 {
207 struct sock *sk = skb->sk;
208 struct rtable *ort = skb_rtable(skb);
209
210 if (!skb->dev && sk && sk_fullsock(sk))
211 ort->dst.ops->update_pmtu(&ort->dst, sk, NULL, mtu, true);
212 }
213
ensure_mtu_is_adequate(struct netns_ipvs * ipvs,int skb_af,int rt_mode,struct ip_vs_iphdr * ipvsh,struct sk_buff * skb,int mtu)214 static inline bool ensure_mtu_is_adequate(struct netns_ipvs *ipvs, int skb_af,
215 int rt_mode,
216 struct ip_vs_iphdr *ipvsh,
217 struct sk_buff *skb, int mtu)
218 {
219 #ifdef CONFIG_IP_VS_IPV6
220 if (skb_af == AF_INET6) {
221 struct net *net = ipvs->net;
222
223 if (unlikely(__mtu_check_toobig_v6(skb, mtu))) {
224 if (!skb->dev)
225 skb->dev = net->loopback_dev;
226 /* only send ICMP too big on first fragment */
227 if (!ipvsh->fragoffs && !ip_vs_iph_icmp(ipvsh))
228 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
229 IP_VS_DBG(1, "frag needed for %pI6c\n",
230 &ipv6_hdr(skb)->saddr);
231 return false;
232 }
233 } else
234 #endif
235 {
236 /* If we're going to tunnel the packet and pmtu discovery
237 * is disabled, we'll just fragment it anyway
238 */
239 if ((rt_mode & IP_VS_RT_MODE_TUNNEL) && !sysctl_pmtu_disc(ipvs))
240 return true;
241
242 if (unlikely(ip_hdr(skb)->frag_off & htons(IP_DF) &&
243 skb->len > mtu && !skb_is_gso(skb) &&
244 !ip_vs_iph_icmp(ipvsh))) {
245 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
246 htonl(mtu));
247 IP_VS_DBG(1, "frag needed for %pI4\n",
248 &ip_hdr(skb)->saddr);
249 return false;
250 }
251 }
252
253 return true;
254 }
255
decrement_ttl(struct netns_ipvs * ipvs,int skb_af,struct sk_buff * skb)256 static inline bool decrement_ttl(struct netns_ipvs *ipvs,
257 int skb_af,
258 struct sk_buff *skb)
259 {
260 struct net *net = ipvs->net;
261
262 #ifdef CONFIG_IP_VS_IPV6
263 if (skb_af == AF_INET6) {
264 struct dst_entry *dst = skb_dst(skb);
265
266 /* check and decrement ttl */
267 if (ipv6_hdr(skb)->hop_limit <= 1) {
268 struct inet6_dev *idev = __in6_dev_get_safely(skb->dev);
269
270 /* Force OUTPUT device used as source address */
271 skb->dev = dst->dev;
272 icmpv6_send(skb, ICMPV6_TIME_EXCEED,
273 ICMPV6_EXC_HOPLIMIT, 0);
274 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
275
276 return false;
277 }
278
279 /* don't propagate ttl change to cloned packets */
280 if (skb_ensure_writable(skb, sizeof(struct ipv6hdr)))
281 return false;
282
283 ipv6_hdr(skb)->hop_limit--;
284 } else
285 #endif
286 {
287 if (ip_hdr(skb)->ttl <= 1) {
288 /* Tell the sender its packet died... */
289 __IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS);
290 icmp_send(skb, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL, 0);
291 return false;
292 }
293
294 /* don't propagate ttl change to cloned packets */
295 if (skb_ensure_writable(skb, sizeof(struct iphdr)))
296 return false;
297
298 /* Decrease ttl */
299 ip_decrease_ttl(ip_hdr(skb));
300 }
301
302 return true;
303 }
304
305 /* Get route to destination or remote server */
306 static int
__ip_vs_get_out_rt(struct netns_ipvs * ipvs,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)307 __ip_vs_get_out_rt(struct netns_ipvs *ipvs, int skb_af, struct sk_buff *skb,
308 struct ip_vs_dest *dest,
309 __be32 daddr, int rt_mode, __be32 *ret_saddr,
310 struct ip_vs_iphdr *ipvsh)
311 {
312 struct net *net = ipvs->net;
313 struct ip_vs_dest_dst *dest_dst;
314 struct rtable *rt; /* Route to the other host */
315 int mtu;
316 int local, noref = 1;
317
318 if (dest) {
319 dest_dst = __ip_vs_dst_check(dest);
320 if (likely(dest_dst))
321 rt = (struct rtable *) dest_dst->dst_cache;
322 else {
323 dest_dst = ip_vs_dest_dst_alloc();
324 spin_lock_bh(&dest->dst_lock);
325 if (!dest_dst) {
326 __ip_vs_dst_set(dest, NULL, NULL, 0);
327 spin_unlock_bh(&dest->dst_lock);
328 goto err_unreach;
329 }
330 rt = do_output_route4(net, dest->addr.ip, rt_mode,
331 &dest_dst->dst_saddr.ip);
332 if (!rt) {
333 __ip_vs_dst_set(dest, NULL, NULL, 0);
334 spin_unlock_bh(&dest->dst_lock);
335 ip_vs_dest_dst_free(dest_dst);
336 goto err_unreach;
337 }
338 __ip_vs_dst_set(dest, dest_dst, &rt->dst, 0);
339 spin_unlock_bh(&dest->dst_lock);
340 IP_VS_DBG(10, "new dst %pI4, src %pI4, refcnt=%d\n",
341 &dest->addr.ip, &dest_dst->dst_saddr.ip,
342 atomic_read(&rt->dst.__refcnt));
343 }
344 if (ret_saddr)
345 *ret_saddr = dest_dst->dst_saddr.ip;
346 } else {
347 __be32 saddr = htonl(INADDR_ANY);
348
349 noref = 0;
350
351 /* For such unconfigured boxes avoid many route lookups
352 * for performance reasons because we do not remember saddr
353 */
354 rt_mode &= ~IP_VS_RT_MODE_CONNECT;
355 rt = do_output_route4(net, daddr, rt_mode, &saddr);
356 if (!rt)
357 goto err_unreach;
358 if (ret_saddr)
359 *ret_saddr = saddr;
360 }
361
362 local = (rt->rt_flags & RTCF_LOCAL) ? 1 : 0;
363 if (unlikely(crosses_local_route_boundary(skb_af, skb, rt_mode,
364 local))) {
365 IP_VS_DBG_RL("We are crossing local and non-local addresses"
366 " daddr=%pI4\n", &daddr);
367 goto err_put;
368 }
369
370 if (unlikely(local)) {
371 /* skb to local stack, preserve old route */
372 if (!noref)
373 ip_rt_put(rt);
374 return local;
375 }
376
377 if (!decrement_ttl(ipvs, skb_af, skb))
378 goto err_put;
379
380 if (likely(!(rt_mode & IP_VS_RT_MODE_TUNNEL))) {
381 mtu = dst_mtu(&rt->dst);
382 } else {
383 mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
384 if (!dest)
385 goto err_put;
386 if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
387 mtu -= sizeof(struct udphdr) + sizeof(struct guehdr);
388 if ((dest->tun_flags &
389 IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
390 skb->ip_summed == CHECKSUM_PARTIAL)
391 mtu -= GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
392 } else if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GRE) {
393 __be16 tflags = 0;
394
395 if (dest->tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM)
396 tflags |= TUNNEL_CSUM;
397 mtu -= gre_calc_hlen(tflags);
398 }
399 if (mtu < 68) {
400 IP_VS_DBG_RL("%s(): mtu less than 68\n", __func__);
401 goto err_put;
402 }
403 maybe_update_pmtu(skb_af, skb, mtu);
404 }
405
406 if (!ensure_mtu_is_adequate(ipvs, skb_af, rt_mode, ipvsh, skb, mtu))
407 goto err_put;
408
409 skb_dst_drop(skb);
410 if (noref)
411 skb_dst_set_noref(skb, &rt->dst);
412 else
413 skb_dst_set(skb, &rt->dst);
414
415 return local;
416
417 err_put:
418 if (!noref)
419 ip_rt_put(rt);
420 return -1;
421
422 err_unreach:
423 dst_link_failure(skb);
424 return -1;
425 }
426
427 #ifdef CONFIG_IP_VS_IPV6
428 static struct dst_entry *
__ip_vs_route_output_v6(struct net * net,struct in6_addr * daddr,struct in6_addr * ret_saddr,int do_xfrm,int rt_mode)429 __ip_vs_route_output_v6(struct net *net, struct in6_addr *daddr,
430 struct in6_addr *ret_saddr, int do_xfrm, int rt_mode)
431 {
432 struct dst_entry *dst;
433 struct flowi6 fl6 = {
434 .daddr = *daddr,
435 };
436
437 if (rt_mode & IP_VS_RT_MODE_KNOWN_NH)
438 fl6.flowi6_flags = FLOWI_FLAG_KNOWN_NH;
439
440 dst = ip6_route_output(net, NULL, &fl6);
441 if (dst->error)
442 goto out_err;
443 if (!ret_saddr)
444 return dst;
445 if (ipv6_addr_any(&fl6.saddr) &&
446 ipv6_dev_get_saddr(net, ip6_dst_idev(dst)->dev,
447 &fl6.daddr, 0, &fl6.saddr) < 0)
448 goto out_err;
449 if (do_xfrm) {
450 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
451 if (IS_ERR(dst)) {
452 dst = NULL;
453 goto out_err;
454 }
455 }
456 *ret_saddr = fl6.saddr;
457 return dst;
458
459 out_err:
460 dst_release(dst);
461 IP_VS_DBG_RL("ip6_route_output error, dest: %pI6\n", daddr);
462 return NULL;
463 }
464
465 /*
466 * Get route to destination or remote server
467 */
468 static int
__ip_vs_get_out_rt_v6(struct netns_ipvs * ipvs,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)469 __ip_vs_get_out_rt_v6(struct netns_ipvs *ipvs, int skb_af, struct sk_buff *skb,
470 struct ip_vs_dest *dest,
471 struct in6_addr *daddr, struct in6_addr *ret_saddr,
472 struct ip_vs_iphdr *ipvsh, int do_xfrm, int rt_mode)
473 {
474 struct net *net = ipvs->net;
475 struct ip_vs_dest_dst *dest_dst;
476 struct rt6_info *rt; /* Route to the other host */
477 struct dst_entry *dst;
478 int mtu;
479 int local, noref = 1;
480
481 if (dest) {
482 dest_dst = __ip_vs_dst_check(dest);
483 if (likely(dest_dst))
484 rt = (struct rt6_info *) dest_dst->dst_cache;
485 else {
486 u32 cookie;
487
488 dest_dst = ip_vs_dest_dst_alloc();
489 spin_lock_bh(&dest->dst_lock);
490 if (!dest_dst) {
491 __ip_vs_dst_set(dest, NULL, NULL, 0);
492 spin_unlock_bh(&dest->dst_lock);
493 goto err_unreach;
494 }
495 dst = __ip_vs_route_output_v6(net, &dest->addr.in6,
496 &dest_dst->dst_saddr.in6,
497 do_xfrm, rt_mode);
498 if (!dst) {
499 __ip_vs_dst_set(dest, NULL, NULL, 0);
500 spin_unlock_bh(&dest->dst_lock);
501 ip_vs_dest_dst_free(dest_dst);
502 goto err_unreach;
503 }
504 rt = (struct rt6_info *) dst;
505 cookie = rt6_get_cookie(rt);
506 __ip_vs_dst_set(dest, dest_dst, &rt->dst, cookie);
507 spin_unlock_bh(&dest->dst_lock);
508 IP_VS_DBG(10, "new dst %pI6, src %pI6, refcnt=%d\n",
509 &dest->addr.in6, &dest_dst->dst_saddr.in6,
510 atomic_read(&rt->dst.__refcnt));
511 }
512 if (ret_saddr)
513 *ret_saddr = dest_dst->dst_saddr.in6;
514 } else {
515 noref = 0;
516 dst = __ip_vs_route_output_v6(net, daddr, ret_saddr, do_xfrm,
517 rt_mode);
518 if (!dst)
519 goto err_unreach;
520 rt = (struct rt6_info *) dst;
521 }
522
523 local = __ip_vs_is_local_route6(rt);
524
525 if (unlikely(crosses_local_route_boundary(skb_af, skb, rt_mode,
526 local))) {
527 IP_VS_DBG_RL("We are crossing local and non-local addresses"
528 " daddr=%pI6\n", daddr);
529 goto err_put;
530 }
531
532 if (unlikely(local)) {
533 /* skb to local stack, preserve old route */
534 if (!noref)
535 dst_release(&rt->dst);
536 return local;
537 }
538
539 if (!decrement_ttl(ipvs, skb_af, skb))
540 goto err_put;
541
542 /* MTU checking */
543 if (likely(!(rt_mode & IP_VS_RT_MODE_TUNNEL)))
544 mtu = dst_mtu(&rt->dst);
545 else {
546 mtu = dst_mtu(&rt->dst) - sizeof(struct ipv6hdr);
547 if (!dest)
548 goto err_put;
549 if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
550 mtu -= sizeof(struct udphdr) + sizeof(struct guehdr);
551 if ((dest->tun_flags &
552 IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
553 skb->ip_summed == CHECKSUM_PARTIAL)
554 mtu -= GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
555 } else if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GRE) {
556 __be16 tflags = 0;
557
558 if (dest->tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM)
559 tflags |= TUNNEL_CSUM;
560 mtu -= gre_calc_hlen(tflags);
561 }
562 if (mtu < IPV6_MIN_MTU) {
563 IP_VS_DBG_RL("%s(): mtu less than %d\n", __func__,
564 IPV6_MIN_MTU);
565 goto err_put;
566 }
567 maybe_update_pmtu(skb_af, skb, mtu);
568 }
569
570 if (!ensure_mtu_is_adequate(ipvs, skb_af, rt_mode, ipvsh, skb, mtu))
571 goto err_put;
572
573 skb_dst_drop(skb);
574 if (noref)
575 skb_dst_set_noref(skb, &rt->dst);
576 else
577 skb_dst_set(skb, &rt->dst);
578
579 return local;
580
581 err_put:
582 if (!noref)
583 dst_release(&rt->dst);
584 return -1;
585
586 err_unreach:
587 /* The ip6_link_failure function requires the dev field to be set
588 * in order to get the net (further for the sake of fwmark
589 * reflection).
590 */
591 if (!skb->dev)
592 skb->dev = skb_dst(skb)->dev;
593
594 dst_link_failure(skb);
595 return -1;
596 }
597 #endif
598
599
600 /* 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)601 static inline int ip_vs_tunnel_xmit_prepare(struct sk_buff *skb,
602 struct ip_vs_conn *cp)
603 {
604 int ret = NF_ACCEPT;
605
606 skb->ipvs_property = 1;
607 if (unlikely(cp->flags & IP_VS_CONN_F_NFCT))
608 ret = ip_vs_confirm_conntrack(skb);
609 if (ret == NF_ACCEPT) {
610 nf_reset_ct(skb);
611 skb_forward_csum(skb);
612 if (skb->dev)
613 skb_clear_tstamp(skb);
614 }
615 return ret;
616 }
617
618 /* In the event of a remote destination, it's possible that we would have
619 * matches against an old socket (particularly a TIME-WAIT socket). This
620 * causes havoc down the line (ip_local_out et. al. expect regular sockets
621 * and invalid memory accesses will happen) so simply drop the association
622 * in this case.
623 */
ip_vs_drop_early_demux_sk(struct sk_buff * skb)624 static inline void ip_vs_drop_early_demux_sk(struct sk_buff *skb)
625 {
626 /* If dev is set, the packet came from the LOCAL_IN callback and
627 * not from a local TCP socket.
628 */
629 if (skb->dev)
630 skb_orphan(skb);
631 }
632
633 /* 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)634 static inline int ip_vs_nat_send_or_cont(int pf, struct sk_buff *skb,
635 struct ip_vs_conn *cp, int local)
636 {
637 int ret = NF_STOLEN;
638
639 skb->ipvs_property = 1;
640 if (likely(!(cp->flags & IP_VS_CONN_F_NFCT)))
641 ip_vs_notrack(skb);
642 else
643 ip_vs_update_conntrack(skb, cp, 1);
644
645 /* Remove the early_demux association unless it's bound for the
646 * exact same port and address on this host after translation.
647 */
648 if (!local || cp->vport != cp->dport ||
649 !ip_vs_addr_equal(cp->af, &cp->vaddr, &cp->daddr))
650 ip_vs_drop_early_demux_sk(skb);
651
652 if (!local) {
653 skb_forward_csum(skb);
654 if (skb->dev)
655 skb_clear_tstamp(skb);
656 NF_HOOK(pf, NF_INET_LOCAL_OUT, cp->ipvs->net, NULL, skb,
657 NULL, skb_dst(skb)->dev, dst_output);
658 } else
659 ret = NF_ACCEPT;
660
661 return ret;
662 }
663
664 /* 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)665 static inline int ip_vs_send_or_cont(int pf, struct sk_buff *skb,
666 struct ip_vs_conn *cp, int local)
667 {
668 int ret = NF_STOLEN;
669
670 skb->ipvs_property = 1;
671 if (likely(!(cp->flags & IP_VS_CONN_F_NFCT)))
672 ip_vs_notrack(skb);
673 if (!local) {
674 ip_vs_drop_early_demux_sk(skb);
675 skb_forward_csum(skb);
676 if (skb->dev)
677 skb_clear_tstamp(skb);
678 NF_HOOK(pf, NF_INET_LOCAL_OUT, cp->ipvs->net, NULL, skb,
679 NULL, skb_dst(skb)->dev, dst_output);
680 } else
681 ret = NF_ACCEPT;
682 return ret;
683 }
684
685
686 /*
687 * NULL transmitter (do nothing except return NF_ACCEPT)
688 */
689 int
ip_vs_null_xmit(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)690 ip_vs_null_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
691 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
692 {
693 /* we do not touch skb and do not need pskb ptr */
694 return ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 1);
695 }
696
697
698 /*
699 * Bypass transmitter
700 * Let packets bypass the destination when the destination is not
701 * available, it may be only used in transparent cache cluster.
702 */
703 int
ip_vs_bypass_xmit(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)704 ip_vs_bypass_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
705 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
706 {
707 struct iphdr *iph = ip_hdr(skb);
708
709 EnterFunction(10);
710
711 if (__ip_vs_get_out_rt(cp->ipvs, cp->af, skb, NULL, iph->daddr,
712 IP_VS_RT_MODE_NON_LOCAL, NULL, ipvsh) < 0)
713 goto tx_error;
714
715 ip_send_check(iph);
716
717 /* Another hack: avoid icmp_send in ip_fragment */
718 skb->ignore_df = 1;
719
720 ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 0);
721
722 LeaveFunction(10);
723 return NF_STOLEN;
724
725 tx_error:
726 kfree_skb(skb);
727 LeaveFunction(10);
728 return NF_STOLEN;
729 }
730
731 #ifdef CONFIG_IP_VS_IPV6
732 int
ip_vs_bypass_xmit_v6(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)733 ip_vs_bypass_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
734 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
735 {
736 struct ipv6hdr *iph = ipv6_hdr(skb);
737
738 EnterFunction(10);
739
740 if (__ip_vs_get_out_rt_v6(cp->ipvs, cp->af, skb, NULL,
741 &iph->daddr, NULL,
742 ipvsh, 0, IP_VS_RT_MODE_NON_LOCAL) < 0)
743 goto tx_error;
744
745 /* Another hack: avoid icmp_send in ip_fragment */
746 skb->ignore_df = 1;
747
748 ip_vs_send_or_cont(NFPROTO_IPV6, skb, cp, 0);
749
750 LeaveFunction(10);
751 return NF_STOLEN;
752
753 tx_error:
754 kfree_skb(skb);
755 LeaveFunction(10);
756 return NF_STOLEN;
757 }
758 #endif
759
760 /*
761 * NAT transmitter (only for outside-to-inside nat forwarding)
762 * Not used for related ICMP
763 */
764 int
ip_vs_nat_xmit(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)765 ip_vs_nat_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
766 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
767 {
768 struct rtable *rt; /* Route to the other host */
769 int local, rc, was_input;
770
771 EnterFunction(10);
772
773 /* check if it is a connection of no-client-port */
774 if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT)) {
775 __be16 _pt, *p;
776
777 p = skb_header_pointer(skb, ipvsh->len, sizeof(_pt), &_pt);
778 if (p == NULL)
779 goto tx_error;
780 ip_vs_conn_fill_cport(cp, *p);
781 IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
782 }
783
784 was_input = rt_is_input_route(skb_rtable(skb));
785 local = __ip_vs_get_out_rt(cp->ipvs, cp->af, skb, cp->dest, cp->daddr.ip,
786 IP_VS_RT_MODE_LOCAL |
787 IP_VS_RT_MODE_NON_LOCAL |
788 IP_VS_RT_MODE_RDR, NULL, ipvsh);
789 if (local < 0)
790 goto tx_error;
791 rt = skb_rtable(skb);
792 /*
793 * Avoid duplicate tuple in reply direction for NAT traffic
794 * to local address when connection is sync-ed
795 */
796 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
797 if (cp->flags & IP_VS_CONN_F_SYNC && local) {
798 enum ip_conntrack_info ctinfo;
799 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
800
801 if (ct) {
802 IP_VS_DBG_RL_PKT(10, AF_INET, pp, skb, ipvsh->off,
803 "ip_vs_nat_xmit(): "
804 "stopping DNAT to local address");
805 goto tx_error;
806 }
807 }
808 #endif
809
810 /* From world but DNAT to loopback address? */
811 if (local && ipv4_is_loopback(cp->daddr.ip) && was_input) {
812 IP_VS_DBG_RL_PKT(1, AF_INET, pp, skb, ipvsh->off,
813 "ip_vs_nat_xmit(): stopping DNAT to loopback "
814 "address");
815 goto tx_error;
816 }
817
818 /* copy-on-write the packet before mangling it */
819 if (skb_ensure_writable(skb, sizeof(struct iphdr)))
820 goto tx_error;
821
822 if (skb_cow(skb, rt->dst.dev->hard_header_len))
823 goto tx_error;
824
825 /* mangle the packet */
826 if (pp->dnat_handler && !pp->dnat_handler(skb, pp, cp, ipvsh))
827 goto tx_error;
828 ip_hdr(skb)->daddr = cp->daddr.ip;
829 ip_send_check(ip_hdr(skb));
830
831 IP_VS_DBG_PKT(10, AF_INET, pp, skb, ipvsh->off, "After DNAT");
832
833 /* FIXME: when application helper enlarges the packet and the length
834 is larger than the MTU of outgoing device, there will be still
835 MTU problem. */
836
837 /* Another hack: avoid icmp_send in ip_fragment */
838 skb->ignore_df = 1;
839
840 rc = ip_vs_nat_send_or_cont(NFPROTO_IPV4, skb, cp, local);
841
842 LeaveFunction(10);
843 return rc;
844
845 tx_error:
846 kfree_skb(skb);
847 LeaveFunction(10);
848 return NF_STOLEN;
849 }
850
851 #ifdef CONFIG_IP_VS_IPV6
852 int
ip_vs_nat_xmit_v6(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)853 ip_vs_nat_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
854 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
855 {
856 struct rt6_info *rt; /* Route to the other host */
857 int local, rc;
858
859 EnterFunction(10);
860
861 /* check if it is a connection of no-client-port */
862 if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT && !ipvsh->fragoffs)) {
863 __be16 _pt, *p;
864 p = skb_header_pointer(skb, ipvsh->len, sizeof(_pt), &_pt);
865 if (p == NULL)
866 goto tx_error;
867 ip_vs_conn_fill_cport(cp, *p);
868 IP_VS_DBG(10, "filled cport=%d\n", ntohs(*p));
869 }
870
871 local = __ip_vs_get_out_rt_v6(cp->ipvs, cp->af, skb, cp->dest,
872 &cp->daddr.in6,
873 NULL, ipvsh, 0,
874 IP_VS_RT_MODE_LOCAL |
875 IP_VS_RT_MODE_NON_LOCAL |
876 IP_VS_RT_MODE_RDR);
877 if (local < 0)
878 goto tx_error;
879 rt = (struct rt6_info *) skb_dst(skb);
880 /*
881 * Avoid duplicate tuple in reply direction for NAT traffic
882 * to local address when connection is sync-ed
883 */
884 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
885 if (cp->flags & IP_VS_CONN_F_SYNC && local) {
886 enum ip_conntrack_info ctinfo;
887 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
888
889 if (ct) {
890 IP_VS_DBG_RL_PKT(10, AF_INET6, pp, skb, ipvsh->off,
891 "ip_vs_nat_xmit_v6(): "
892 "stopping DNAT to local address");
893 goto tx_error;
894 }
895 }
896 #endif
897
898 /* From world but DNAT to loopback address? */
899 if (local && skb->dev && !(skb->dev->flags & IFF_LOOPBACK) &&
900 ipv6_addr_type(&cp->daddr.in6) & IPV6_ADDR_LOOPBACK) {
901 IP_VS_DBG_RL_PKT(1, AF_INET6, pp, skb, ipvsh->off,
902 "ip_vs_nat_xmit_v6(): "
903 "stopping DNAT to loopback address");
904 goto tx_error;
905 }
906
907 /* copy-on-write the packet before mangling it */
908 if (skb_ensure_writable(skb, sizeof(struct ipv6hdr)))
909 goto tx_error;
910
911 if (skb_cow(skb, rt->dst.dev->hard_header_len))
912 goto tx_error;
913
914 /* mangle the packet */
915 if (pp->dnat_handler && !pp->dnat_handler(skb, pp, cp, ipvsh))
916 goto tx_error;
917 ipv6_hdr(skb)->daddr = cp->daddr.in6;
918
919 IP_VS_DBG_PKT(10, AF_INET6, pp, skb, ipvsh->off, "After DNAT");
920
921 /* FIXME: when application helper enlarges the packet and the length
922 is larger than the MTU of outgoing device, there will be still
923 MTU problem. */
924
925 /* Another hack: avoid icmp_send in ip_fragment */
926 skb->ignore_df = 1;
927
928 rc = ip_vs_nat_send_or_cont(NFPROTO_IPV6, skb, cp, local);
929
930 LeaveFunction(10);
931 return rc;
932
933 tx_error:
934 LeaveFunction(10);
935 kfree_skb(skb);
936 return NF_STOLEN;
937 }
938 #endif
939
940 /* When forwarding a packet, we must ensure that we've got enough headroom
941 * for the encapsulation packet in the skb. This also gives us an
942 * opportunity to figure out what the payload_len, dsfield, ttl, and df
943 * values should be, so that we won't need to look at the old ip header
944 * again
945 */
946 static struct sk_buff *
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)947 ip_vs_prepare_tunneled_skb(struct sk_buff *skb, int skb_af,
948 unsigned int max_headroom, __u8 *next_protocol,
949 __u32 *payload_len, __u8 *dsfield, __u8 *ttl,
950 __be16 *df)
951 {
952 struct sk_buff *new_skb = NULL;
953 struct iphdr *old_iph = NULL;
954 __u8 old_dsfield;
955 #ifdef CONFIG_IP_VS_IPV6
956 struct ipv6hdr *old_ipv6h = NULL;
957 #endif
958
959 ip_vs_drop_early_demux_sk(skb);
960
961 if (skb_headroom(skb) < max_headroom || skb_cloned(skb)) {
962 new_skb = skb_realloc_headroom(skb, max_headroom);
963 if (!new_skb)
964 goto error;
965 if (skb->sk)
966 skb_set_owner_w(new_skb, skb->sk);
967 consume_skb(skb);
968 skb = new_skb;
969 }
970
971 #ifdef CONFIG_IP_VS_IPV6
972 if (skb_af == AF_INET6) {
973 old_ipv6h = ipv6_hdr(skb);
974 *next_protocol = IPPROTO_IPV6;
975 if (payload_len)
976 *payload_len =
977 ntohs(old_ipv6h->payload_len) +
978 sizeof(*old_ipv6h);
979 old_dsfield = ipv6_get_dsfield(old_ipv6h);
980 *ttl = old_ipv6h->hop_limit;
981 if (df)
982 *df = 0;
983 } else
984 #endif
985 {
986 old_iph = ip_hdr(skb);
987 /* Copy DF, reset fragment offset and MF */
988 if (df)
989 *df = (old_iph->frag_off & htons(IP_DF));
990 *next_protocol = IPPROTO_IPIP;
991
992 /* fix old IP header checksum */
993 ip_send_check(old_iph);
994 old_dsfield = ipv4_get_dsfield(old_iph);
995 *ttl = old_iph->ttl;
996 if (payload_len)
997 *payload_len = ntohs(old_iph->tot_len);
998 }
999
1000 /* Implement full-functionality option for ECN encapsulation */
1001 *dsfield = INET_ECN_encapsulate(old_dsfield, old_dsfield);
1002
1003 return skb;
1004 error:
1005 kfree_skb(skb);
1006 return ERR_PTR(-ENOMEM);
1007 }
1008
__tun_gso_type_mask(int encaps_af,int orig_af)1009 static inline int __tun_gso_type_mask(int encaps_af, int orig_af)
1010 {
1011 switch (encaps_af) {
1012 case AF_INET:
1013 return SKB_GSO_IPXIP4;
1014 case AF_INET6:
1015 return SKB_GSO_IPXIP6;
1016 default:
1017 return 0;
1018 }
1019 }
1020
1021 static int
ipvs_gue_encap(struct net * net,struct sk_buff * skb,struct ip_vs_conn * cp,__u8 * next_protocol)1022 ipvs_gue_encap(struct net *net, struct sk_buff *skb,
1023 struct ip_vs_conn *cp, __u8 *next_protocol)
1024 {
1025 __be16 dport;
1026 __be16 sport = udp_flow_src_port(net, skb, 0, 0, false);
1027 struct udphdr *udph; /* Our new UDP header */
1028 struct guehdr *gueh; /* Our new GUE header */
1029 size_t hdrlen, optlen = 0;
1030 void *data;
1031 bool need_priv = false;
1032
1033 if ((cp->dest->tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
1034 skb->ip_summed == CHECKSUM_PARTIAL) {
1035 optlen += GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
1036 need_priv = true;
1037 }
1038
1039 hdrlen = sizeof(struct guehdr) + optlen;
1040
1041 skb_push(skb, hdrlen);
1042
1043 gueh = (struct guehdr *)skb->data;
1044
1045 gueh->control = 0;
1046 gueh->version = 0;
1047 gueh->hlen = optlen >> 2;
1048 gueh->flags = 0;
1049 gueh->proto_ctype = *next_protocol;
1050
1051 data = &gueh[1];
1052
1053 if (need_priv) {
1054 __be32 *flags = data;
1055 u16 csum_start = skb_checksum_start_offset(skb);
1056 __be16 *pd;
1057
1058 gueh->flags |= GUE_FLAG_PRIV;
1059 *flags = 0;
1060 data += GUE_LEN_PRIV;
1061
1062 if (csum_start < hdrlen)
1063 return -EINVAL;
1064
1065 csum_start -= hdrlen;
1066 pd = data;
1067 pd[0] = htons(csum_start);
1068 pd[1] = htons(csum_start + skb->csum_offset);
1069
1070 if (!skb_is_gso(skb)) {
1071 skb->ip_summed = CHECKSUM_NONE;
1072 skb->encapsulation = 0;
1073 }
1074
1075 *flags |= GUE_PFLAG_REMCSUM;
1076 data += GUE_PLEN_REMCSUM;
1077 }
1078
1079 skb_push(skb, sizeof(struct udphdr));
1080 skb_reset_transport_header(skb);
1081
1082 udph = udp_hdr(skb);
1083
1084 dport = cp->dest->tun_port;
1085 udph->dest = dport;
1086 udph->source = sport;
1087 udph->len = htons(skb->len);
1088 udph->check = 0;
1089
1090 *next_protocol = IPPROTO_UDP;
1091
1092 return 0;
1093 }
1094
1095 static void
ipvs_gre_encap(struct net * net,struct sk_buff * skb,struct ip_vs_conn * cp,__u8 * next_protocol)1096 ipvs_gre_encap(struct net *net, struct sk_buff *skb,
1097 struct ip_vs_conn *cp, __u8 *next_protocol)
1098 {
1099 __be16 proto = *next_protocol == IPPROTO_IPIP ?
1100 htons(ETH_P_IP) : htons(ETH_P_IPV6);
1101 __be16 tflags = 0;
1102 size_t hdrlen;
1103
1104 if (cp->dest->tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM)
1105 tflags |= TUNNEL_CSUM;
1106
1107 hdrlen = gre_calc_hlen(tflags);
1108 gre_build_header(skb, hdrlen, tflags, proto, 0, 0);
1109
1110 *next_protocol = IPPROTO_GRE;
1111 }
1112
1113 /*
1114 * IP Tunneling transmitter
1115 *
1116 * This function encapsulates the packet in a new IP packet, its
1117 * destination will be set to cp->daddr. Most code of this function
1118 * is taken from ipip.c.
1119 *
1120 * It is used in VS/TUN cluster. The load balancer selects a real
1121 * server from a cluster based on a scheduling algorithm,
1122 * encapsulates the request packet and forwards it to the selected
1123 * server. For example, all real servers are configured with
1124 * "ifconfig tunl0 <Virtual IP Address> up". When the server receives
1125 * the encapsulated packet, it will decapsulate the packet, processe
1126 * the request and return the response packets directly to the client
1127 * without passing the load balancer. This can greatly increase the
1128 * scalability of virtual server.
1129 *
1130 * Used for ANY protocol
1131 */
1132 int
ip_vs_tunnel_xmit(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)1133 ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
1134 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
1135 {
1136 struct netns_ipvs *ipvs = cp->ipvs;
1137 struct net *net = ipvs->net;
1138 struct rtable *rt; /* Route to the other host */
1139 __be32 saddr; /* Source for tunnel */
1140 struct net_device *tdev; /* Device to other host */
1141 __u8 next_protocol = 0;
1142 __u8 dsfield = 0;
1143 __u8 ttl = 0;
1144 __be16 df = 0;
1145 __be16 *dfp = NULL;
1146 struct iphdr *iph; /* Our new IP header */
1147 unsigned int max_headroom; /* The extra header space needed */
1148 int ret, local;
1149 int tun_type, gso_type;
1150 int tun_flags;
1151
1152 EnterFunction(10);
1153
1154 local = __ip_vs_get_out_rt(ipvs, cp->af, skb, cp->dest, cp->daddr.ip,
1155 IP_VS_RT_MODE_LOCAL |
1156 IP_VS_RT_MODE_NON_LOCAL |
1157 IP_VS_RT_MODE_CONNECT |
1158 IP_VS_RT_MODE_TUNNEL, &saddr, ipvsh);
1159 if (local < 0)
1160 goto tx_error;
1161 if (local)
1162 return ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 1);
1163
1164 rt = skb_rtable(skb);
1165 tdev = rt->dst.dev;
1166
1167 /*
1168 * Okay, now see if we can stuff it in the buffer as-is.
1169 */
1170 max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct iphdr);
1171
1172 tun_type = cp->dest->tun_type;
1173 tun_flags = cp->dest->tun_flags;
1174
1175 if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
1176 size_t gue_hdrlen, gue_optlen = 0;
1177
1178 if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
1179 skb->ip_summed == CHECKSUM_PARTIAL) {
1180 gue_optlen += GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
1181 }
1182 gue_hdrlen = sizeof(struct guehdr) + gue_optlen;
1183
1184 max_headroom += sizeof(struct udphdr) + gue_hdrlen;
1185 } else if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GRE) {
1186 size_t gre_hdrlen;
1187 __be16 tflags = 0;
1188
1189 if (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM)
1190 tflags |= TUNNEL_CSUM;
1191 gre_hdrlen = gre_calc_hlen(tflags);
1192
1193 max_headroom += gre_hdrlen;
1194 }
1195
1196 /* We only care about the df field if sysctl_pmtu_disc(ipvs) is set */
1197 dfp = sysctl_pmtu_disc(ipvs) ? &df : NULL;
1198 skb = ip_vs_prepare_tunneled_skb(skb, cp->af, max_headroom,
1199 &next_protocol, NULL, &dsfield,
1200 &ttl, dfp);
1201 if (IS_ERR(skb))
1202 goto tx_error;
1203
1204 gso_type = __tun_gso_type_mask(AF_INET, cp->af);
1205 if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
1206 if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM) ||
1207 (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM))
1208 gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
1209 else
1210 gso_type |= SKB_GSO_UDP_TUNNEL;
1211 if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
1212 skb->ip_summed == CHECKSUM_PARTIAL) {
1213 gso_type |= SKB_GSO_TUNNEL_REMCSUM;
1214 }
1215 } else if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GRE) {
1216 if (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM)
1217 gso_type |= SKB_GSO_GRE_CSUM;
1218 else
1219 gso_type |= SKB_GSO_GRE;
1220 }
1221
1222 if (iptunnel_handle_offloads(skb, gso_type))
1223 goto tx_error;
1224
1225 skb->transport_header = skb->network_header;
1226
1227 skb_set_inner_ipproto(skb, next_protocol);
1228
1229 if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
1230 bool check = false;
1231
1232 if (ipvs_gue_encap(net, skb, cp, &next_protocol))
1233 goto tx_error;
1234
1235 if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM) ||
1236 (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM))
1237 check = true;
1238
1239 udp_set_csum(!check, skb, saddr, cp->daddr.ip, skb->len);
1240 } else if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GRE)
1241 ipvs_gre_encap(net, skb, cp, &next_protocol);
1242
1243 skb_push(skb, sizeof(struct iphdr));
1244 skb_reset_network_header(skb);
1245 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1246
1247 /*
1248 * Push down and install the IPIP header.
1249 */
1250 iph = ip_hdr(skb);
1251 iph->version = 4;
1252 iph->ihl = sizeof(struct iphdr)>>2;
1253 iph->frag_off = df;
1254 iph->protocol = next_protocol;
1255 iph->tos = dsfield;
1256 iph->daddr = cp->daddr.ip;
1257 iph->saddr = saddr;
1258 iph->ttl = ttl;
1259 ip_select_ident(net, skb, NULL);
1260
1261 /* Another hack: avoid icmp_send in ip_fragment */
1262 skb->ignore_df = 1;
1263
1264 ret = ip_vs_tunnel_xmit_prepare(skb, cp);
1265 if (ret == NF_ACCEPT)
1266 ip_local_out(net, skb->sk, skb);
1267 else if (ret == NF_DROP)
1268 kfree_skb(skb);
1269
1270 LeaveFunction(10);
1271
1272 return NF_STOLEN;
1273
1274 tx_error:
1275 if (!IS_ERR(skb))
1276 kfree_skb(skb);
1277 LeaveFunction(10);
1278 return NF_STOLEN;
1279 }
1280
1281 #ifdef CONFIG_IP_VS_IPV6
1282 int
ip_vs_tunnel_xmit_v6(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)1283 ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
1284 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
1285 {
1286 struct netns_ipvs *ipvs = cp->ipvs;
1287 struct net *net = ipvs->net;
1288 struct rt6_info *rt; /* Route to the other host */
1289 struct in6_addr saddr; /* Source for tunnel */
1290 struct net_device *tdev; /* Device to other host */
1291 __u8 next_protocol = 0;
1292 __u32 payload_len = 0;
1293 __u8 dsfield = 0;
1294 __u8 ttl = 0;
1295 struct ipv6hdr *iph; /* Our new IP header */
1296 unsigned int max_headroom; /* The extra header space needed */
1297 int ret, local;
1298 int tun_type, gso_type;
1299 int tun_flags;
1300
1301 EnterFunction(10);
1302
1303 local = __ip_vs_get_out_rt_v6(ipvs, cp->af, skb, cp->dest,
1304 &cp->daddr.in6,
1305 &saddr, ipvsh, 1,
1306 IP_VS_RT_MODE_LOCAL |
1307 IP_VS_RT_MODE_NON_LOCAL |
1308 IP_VS_RT_MODE_TUNNEL);
1309 if (local < 0)
1310 goto tx_error;
1311 if (local)
1312 return ip_vs_send_or_cont(NFPROTO_IPV6, skb, cp, 1);
1313
1314 rt = (struct rt6_info *) skb_dst(skb);
1315 tdev = rt->dst.dev;
1316
1317 /*
1318 * Okay, now see if we can stuff it in the buffer as-is.
1319 */
1320 max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct ipv6hdr);
1321
1322 tun_type = cp->dest->tun_type;
1323 tun_flags = cp->dest->tun_flags;
1324
1325 if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
1326 size_t gue_hdrlen, gue_optlen = 0;
1327
1328 if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
1329 skb->ip_summed == CHECKSUM_PARTIAL) {
1330 gue_optlen += GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
1331 }
1332 gue_hdrlen = sizeof(struct guehdr) + gue_optlen;
1333
1334 max_headroom += sizeof(struct udphdr) + gue_hdrlen;
1335 } else if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GRE) {
1336 size_t gre_hdrlen;
1337 __be16 tflags = 0;
1338
1339 if (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM)
1340 tflags |= TUNNEL_CSUM;
1341 gre_hdrlen = gre_calc_hlen(tflags);
1342
1343 max_headroom += gre_hdrlen;
1344 }
1345
1346 skb = ip_vs_prepare_tunneled_skb(skb, cp->af, max_headroom,
1347 &next_protocol, &payload_len,
1348 &dsfield, &ttl, NULL);
1349 if (IS_ERR(skb))
1350 goto tx_error;
1351
1352 gso_type = __tun_gso_type_mask(AF_INET6, cp->af);
1353 if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
1354 if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM) ||
1355 (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM))
1356 gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
1357 else
1358 gso_type |= SKB_GSO_UDP_TUNNEL;
1359 if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
1360 skb->ip_summed == CHECKSUM_PARTIAL) {
1361 gso_type |= SKB_GSO_TUNNEL_REMCSUM;
1362 }
1363 } else if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GRE) {
1364 if (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM)
1365 gso_type |= SKB_GSO_GRE_CSUM;
1366 else
1367 gso_type |= SKB_GSO_GRE;
1368 }
1369
1370 if (iptunnel_handle_offloads(skb, gso_type))
1371 goto tx_error;
1372
1373 skb->transport_header = skb->network_header;
1374
1375 skb_set_inner_ipproto(skb, next_protocol);
1376
1377 if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
1378 bool check = false;
1379
1380 if (ipvs_gue_encap(net, skb, cp, &next_protocol))
1381 goto tx_error;
1382
1383 if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM) ||
1384 (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM))
1385 check = true;
1386
1387 udp6_set_csum(!check, skb, &saddr, &cp->daddr.in6, skb->len);
1388 } else if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GRE)
1389 ipvs_gre_encap(net, skb, cp, &next_protocol);
1390
1391 skb_push(skb, sizeof(struct ipv6hdr));
1392 skb_reset_network_header(skb);
1393 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1394
1395 /*
1396 * Push down and install the IPIP header.
1397 */
1398 iph = ipv6_hdr(skb);
1399 iph->version = 6;
1400 iph->nexthdr = next_protocol;
1401 iph->payload_len = htons(payload_len);
1402 memset(&iph->flow_lbl, 0, sizeof(iph->flow_lbl));
1403 ipv6_change_dsfield(iph, 0, dsfield);
1404 iph->daddr = cp->daddr.in6;
1405 iph->saddr = saddr;
1406 iph->hop_limit = ttl;
1407
1408 /* Another hack: avoid icmp_send in ip_fragment */
1409 skb->ignore_df = 1;
1410
1411 ret = ip_vs_tunnel_xmit_prepare(skb, cp);
1412 if (ret == NF_ACCEPT)
1413 ip6_local_out(net, skb->sk, skb);
1414 else if (ret == NF_DROP)
1415 kfree_skb(skb);
1416
1417 LeaveFunction(10);
1418
1419 return NF_STOLEN;
1420
1421 tx_error:
1422 if (!IS_ERR(skb))
1423 kfree_skb(skb);
1424 LeaveFunction(10);
1425 return NF_STOLEN;
1426 }
1427 #endif
1428
1429
1430 /*
1431 * Direct Routing transmitter
1432 * Used for ANY protocol
1433 */
1434 int
ip_vs_dr_xmit(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)1435 ip_vs_dr_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
1436 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
1437 {
1438 int local;
1439
1440 EnterFunction(10);
1441
1442 local = __ip_vs_get_out_rt(cp->ipvs, cp->af, skb, cp->dest, cp->daddr.ip,
1443 IP_VS_RT_MODE_LOCAL |
1444 IP_VS_RT_MODE_NON_LOCAL |
1445 IP_VS_RT_MODE_KNOWN_NH, NULL, ipvsh);
1446 if (local < 0)
1447 goto tx_error;
1448 if (local)
1449 return ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 1);
1450
1451 ip_send_check(ip_hdr(skb));
1452
1453 /* Another hack: avoid icmp_send in ip_fragment */
1454 skb->ignore_df = 1;
1455
1456 ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 0);
1457
1458 LeaveFunction(10);
1459 return NF_STOLEN;
1460
1461 tx_error:
1462 kfree_skb(skb);
1463 LeaveFunction(10);
1464 return NF_STOLEN;
1465 }
1466
1467 #ifdef CONFIG_IP_VS_IPV6
1468 int
ip_vs_dr_xmit_v6(struct sk_buff * skb,struct ip_vs_conn * cp,struct ip_vs_protocol * pp,struct ip_vs_iphdr * ipvsh)1469 ip_vs_dr_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
1470 struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
1471 {
1472 int local;
1473
1474 EnterFunction(10);
1475
1476 local = __ip_vs_get_out_rt_v6(cp->ipvs, cp->af, skb, cp->dest,
1477 &cp->daddr.in6,
1478 NULL, ipvsh, 0,
1479 IP_VS_RT_MODE_LOCAL |
1480 IP_VS_RT_MODE_NON_LOCAL |
1481 IP_VS_RT_MODE_KNOWN_NH);
1482 if (local < 0)
1483 goto tx_error;
1484 if (local)
1485 return ip_vs_send_or_cont(NFPROTO_IPV6, skb, cp, 1);
1486
1487 /* Another hack: avoid icmp_send in ip_fragment */
1488 skb->ignore_df = 1;
1489
1490 ip_vs_send_or_cont(NFPROTO_IPV6, skb, cp, 0);
1491
1492 LeaveFunction(10);
1493 return NF_STOLEN;
1494
1495 tx_error:
1496 kfree_skb(skb);
1497 LeaveFunction(10);
1498 return NF_STOLEN;
1499 }
1500 #endif
1501
1502
1503 /*
1504 * ICMP packet transmitter
1505 * called by the ip_vs_in_icmp
1506 */
1507 int
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)1508 ip_vs_icmp_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
1509 struct ip_vs_protocol *pp, int offset, unsigned int hooknum,
1510 struct ip_vs_iphdr *iph)
1511 {
1512 struct rtable *rt; /* Route to the other host */
1513 int rc;
1514 int local;
1515 int rt_mode, was_input;
1516
1517 EnterFunction(10);
1518
1519 /* The ICMP packet for VS/TUN, VS/DR and LOCALNODE will be
1520 forwarded directly here, because there is no need to
1521 translate address/port back */
1522 if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ) {
1523 if (cp->packet_xmit)
1524 rc = cp->packet_xmit(skb, cp, pp, iph);
1525 else
1526 rc = NF_ACCEPT;
1527 /* do not touch skb anymore */
1528 atomic_inc(&cp->in_pkts);
1529 goto out;
1530 }
1531
1532 /*
1533 * mangle and send the packet here (only for VS/NAT)
1534 */
1535 was_input = rt_is_input_route(skb_rtable(skb));
1536
1537 /* LOCALNODE from FORWARD hook is not supported */
1538 rt_mode = (hooknum != NF_INET_FORWARD) ?
1539 IP_VS_RT_MODE_LOCAL | IP_VS_RT_MODE_NON_LOCAL |
1540 IP_VS_RT_MODE_RDR : IP_VS_RT_MODE_NON_LOCAL;
1541 local = __ip_vs_get_out_rt(cp->ipvs, cp->af, skb, cp->dest, cp->daddr.ip, rt_mode,
1542 NULL, iph);
1543 if (local < 0)
1544 goto tx_error;
1545 rt = skb_rtable(skb);
1546
1547 /*
1548 * Avoid duplicate tuple in reply direction for NAT traffic
1549 * to local address when connection is sync-ed
1550 */
1551 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
1552 if (cp->flags & IP_VS_CONN_F_SYNC && local) {
1553 enum ip_conntrack_info ctinfo;
1554 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
1555
1556 if (ct) {
1557 IP_VS_DBG(10, "%s(): "
1558 "stopping DNAT to local address %pI4\n",
1559 __func__, &cp->daddr.ip);
1560 goto tx_error;
1561 }
1562 }
1563 #endif
1564
1565 /* From world but DNAT to loopback address? */
1566 if (local && ipv4_is_loopback(cp->daddr.ip) && was_input) {
1567 IP_VS_DBG(1, "%s(): "
1568 "stopping DNAT to loopback %pI4\n",
1569 __func__, &cp->daddr.ip);
1570 goto tx_error;
1571 }
1572
1573 /* copy-on-write the packet before mangling it */
1574 if (skb_ensure_writable(skb, offset))
1575 goto tx_error;
1576
1577 if (skb_cow(skb, rt->dst.dev->hard_header_len))
1578 goto tx_error;
1579
1580 ip_vs_nat_icmp(skb, pp, cp, 0);
1581
1582 /* Another hack: avoid icmp_send in ip_fragment */
1583 skb->ignore_df = 1;
1584
1585 rc = ip_vs_nat_send_or_cont(NFPROTO_IPV4, skb, cp, local);
1586 goto out;
1587
1588 tx_error:
1589 kfree_skb(skb);
1590 rc = NF_STOLEN;
1591 out:
1592 LeaveFunction(10);
1593 return rc;
1594 }
1595
1596 #ifdef CONFIG_IP_VS_IPV6
1597 int
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)1598 ip_vs_icmp_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
1599 struct ip_vs_protocol *pp, int offset, unsigned int hooknum,
1600 struct ip_vs_iphdr *ipvsh)
1601 {
1602 struct rt6_info *rt; /* Route to the other host */
1603 int rc;
1604 int local;
1605 int rt_mode;
1606
1607 EnterFunction(10);
1608
1609 /* The ICMP packet for VS/TUN, VS/DR and LOCALNODE will be
1610 forwarded directly here, because there is no need to
1611 translate address/port back */
1612 if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ) {
1613 if (cp->packet_xmit)
1614 rc = cp->packet_xmit(skb, cp, pp, ipvsh);
1615 else
1616 rc = NF_ACCEPT;
1617 /* do not touch skb anymore */
1618 atomic_inc(&cp->in_pkts);
1619 goto out;
1620 }
1621
1622 /*
1623 * mangle and send the packet here (only for VS/NAT)
1624 */
1625
1626 /* LOCALNODE from FORWARD hook is not supported */
1627 rt_mode = (hooknum != NF_INET_FORWARD) ?
1628 IP_VS_RT_MODE_LOCAL | IP_VS_RT_MODE_NON_LOCAL |
1629 IP_VS_RT_MODE_RDR : IP_VS_RT_MODE_NON_LOCAL;
1630 local = __ip_vs_get_out_rt_v6(cp->ipvs, cp->af, skb, cp->dest,
1631 &cp->daddr.in6, NULL, ipvsh, 0, rt_mode);
1632 if (local < 0)
1633 goto tx_error;
1634 rt = (struct rt6_info *) skb_dst(skb);
1635 /*
1636 * Avoid duplicate tuple in reply direction for NAT traffic
1637 * to local address when connection is sync-ed
1638 */
1639 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
1640 if (cp->flags & IP_VS_CONN_F_SYNC && local) {
1641 enum ip_conntrack_info ctinfo;
1642 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
1643
1644 if (ct) {
1645 IP_VS_DBG(10, "%s(): "
1646 "stopping DNAT to local address %pI6\n",
1647 __func__, &cp->daddr.in6);
1648 goto tx_error;
1649 }
1650 }
1651 #endif
1652
1653 /* From world but DNAT to loopback address? */
1654 if (local && skb->dev && !(skb->dev->flags & IFF_LOOPBACK) &&
1655 ipv6_addr_type(&cp->daddr.in6) & IPV6_ADDR_LOOPBACK) {
1656 IP_VS_DBG(1, "%s(): "
1657 "stopping DNAT to loopback %pI6\n",
1658 __func__, &cp->daddr.in6);
1659 goto tx_error;
1660 }
1661
1662 /* copy-on-write the packet before mangling it */
1663 if (skb_ensure_writable(skb, offset))
1664 goto tx_error;
1665
1666 if (skb_cow(skb, rt->dst.dev->hard_header_len))
1667 goto tx_error;
1668
1669 ip_vs_nat_icmp_v6(skb, pp, cp, 0);
1670
1671 /* Another hack: avoid icmp_send in ip_fragment */
1672 skb->ignore_df = 1;
1673
1674 rc = ip_vs_nat_send_or_cont(NFPROTO_IPV6, skb, cp, local);
1675 goto out;
1676
1677 tx_error:
1678 kfree_skb(skb);
1679 rc = NF_STOLEN;
1680 out:
1681 LeaveFunction(10);
1682 return rc;
1683 }
1684 #endif
1685