Loading...
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * IPv6 input
4 * Linux INET6 implementation
5 *
6 * Authors:
7 * Pedro Roque <roque@di.fc.ul.pt>
8 * Ian P. Morris <I.P.Morris@soton.ac.uk>
9 *
10 * Based in linux/net/ipv4/ip_input.c
11 */
12/* Changes
13 *
14 * Mitsuru KANDA @USAGI and
15 * YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs().
16 */
17
18#include <linux/errno.h>
19#include <linux/types.h>
20#include <linux/socket.h>
21#include <linux/sockios.h>
22#include <linux/net.h>
23#include <linux/netdevice.h>
24#include <linux/in6.h>
25#include <linux/icmpv6.h>
26#include <linux/mroute6.h>
27#include <linux/slab.h>
28#include <linux/indirect_call_wrapper.h>
29
30#include <linux/netfilter.h>
31#include <linux/netfilter_ipv6.h>
32
33#include <net/sock.h>
34#include <net/snmp.h>
35#include <net/udp.h>
36
37#include <net/ipv6.h>
38#include <net/protocol.h>
39#include <net/transp_v6.h>
40#include <net/rawv6.h>
41#include <net/ndisc.h>
42#include <net/ip6_route.h>
43#include <net/addrconf.h>
44#include <net/xfrm.h>
45#include <net/inet_ecn.h>
46#include <net/dst_metadata.h>
47
48static void ip6_rcv_finish_core(struct net *net, struct sock *sk,
49 struct sk_buff *skb)
50{
51 if (READ_ONCE(net->ipv4.sysctl_ip_early_demux) &&
52 !skb_dst(skb) && !skb->sk) {
53 switch (ipv6_hdr(skb)->nexthdr) {
54 case IPPROTO_TCP:
55 if (READ_ONCE(net->ipv4.sysctl_tcp_early_demux))
56 tcp_v6_early_demux(skb);
57 break;
58 case IPPROTO_UDP:
59 if (READ_ONCE(net->ipv4.sysctl_udp_early_demux))
60 udp_v6_early_demux(skb);
61 break;
62 }
63 }
64
65 if (!skb_valid_dst(skb))
66 ip6_route_input(skb);
67}
68
69int ip6_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
70{
71 /* if ingress device is enslaved to an L3 master device pass the
72 * skb to its handler for processing
73 */
74 skb = l3mdev_ip6_rcv(skb);
75 if (!skb)
76 return NET_RX_SUCCESS;
77 ip6_rcv_finish_core(net, sk, skb);
78
79 return dst_input(skb);
80}
81
82static void ip6_sublist_rcv_finish(struct list_head *head)
83{
84 struct sk_buff *skb, *next;
85
86 list_for_each_entry_safe(skb, next, head, list) {
87 skb_list_del_init(skb);
88 dst_input(skb);
89 }
90}
91
92static bool ip6_can_use_hint(const struct sk_buff *skb,
93 const struct sk_buff *hint)
94{
95 return hint && !skb_dst(skb) &&
96 ipv6_addr_equal(&ipv6_hdr(hint)->daddr, &ipv6_hdr(skb)->daddr);
97}
98
99static struct sk_buff *ip6_extract_route_hint(const struct net *net,
100 struct sk_buff *skb)
101{
102 if (fib6_routes_require_src(net) || fib6_has_custom_rules(net) ||
103 IP6CB(skb)->flags & IP6SKB_MULTIPATH)
104 return NULL;
105
106 return skb;
107}
108
109static void ip6_list_rcv_finish(struct net *net, struct sock *sk,
110 struct list_head *head)
111{
112 struct sk_buff *skb, *next, *hint = NULL;
113 struct dst_entry *curr_dst = NULL;
114 LIST_HEAD(sublist);
115
116 list_for_each_entry_safe(skb, next, head, list) {
117 struct dst_entry *dst;
118
119 skb_list_del_init(skb);
120 /* if ingress device is enslaved to an L3 master device pass the
121 * skb to its handler for processing
122 */
123 skb = l3mdev_ip6_rcv(skb);
124 if (!skb)
125 continue;
126
127 if (ip6_can_use_hint(skb, hint))
128 skb_dst_copy(skb, hint);
129 else
130 ip6_rcv_finish_core(net, sk, skb);
131 dst = skb_dst(skb);
132 if (curr_dst != dst) {
133 hint = ip6_extract_route_hint(net, skb);
134
135 /* dispatch old sublist */
136 if (!list_empty(&sublist))
137 ip6_sublist_rcv_finish(&sublist);
138 /* start new sublist */
139 INIT_LIST_HEAD(&sublist);
140 curr_dst = dst;
141 }
142 list_add_tail(&skb->list, &sublist);
143 }
144 /* dispatch final sublist */
145 ip6_sublist_rcv_finish(&sublist);
146}
147
148static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
149 struct net *net)
150{
151 enum skb_drop_reason reason;
152 const struct ipv6hdr *hdr;
153 u32 pkt_len;
154 struct inet6_dev *idev;
155
156 if (skb->pkt_type == PACKET_OTHERHOST) {
157 dev_core_stats_rx_otherhost_dropped_inc(skb->dev);
158 kfree_skb_reason(skb, SKB_DROP_REASON_OTHERHOST);
159 return NULL;
160 }
161
162 rcu_read_lock();
163
164 idev = __in6_dev_get(skb->dev);
165
166 __IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_IN, skb->len);
167
168 SKB_DR_SET(reason, NOT_SPECIFIED);
169 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
170 !idev || unlikely(READ_ONCE(idev->cnf.disable_ipv6))) {
171 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
172 if (idev && unlikely(READ_ONCE(idev->cnf.disable_ipv6)))
173 SKB_DR_SET(reason, IPV6DISABLED);
174 goto drop;
175 }
176
177 memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
178
179 /*
180 * Store incoming device index. When the packet will
181 * be queued, we cannot refer to skb->dev anymore.
182 *
183 * BTW, when we send a packet for our own local address on a
184 * non-loopback interface (e.g. ethX), it is being delivered
185 * via the loopback interface (lo) here; skb->dev = loopback_dev.
186 * It, however, should be considered as if it is being
187 * arrived via the sending interface (ethX), because of the
188 * nature of scoping architecture. --yoshfuji
189 */
190 IP6CB(skb)->iif = skb_valid_dst(skb) ? ip6_dst_idev(skb_dst(skb))->dev->ifindex : dev->ifindex;
191
192 if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
193 goto err;
194
195 hdr = ipv6_hdr(skb);
196
197 if (hdr->version != 6) {
198 SKB_DR_SET(reason, UNHANDLED_PROTO);
199 goto err;
200 }
201
202 __IP6_ADD_STATS(net, idev,
203 IPSTATS_MIB_NOECTPKTS +
204 (ipv6_get_dsfield(hdr) & INET_ECN_MASK),
205 max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs));
206 /*
207 * RFC4291 2.5.3
208 * The loopback address must not be used as the source address in IPv6
209 * packets that are sent outside of a single node. [..]
210 * A packet received on an interface with a destination address
211 * of loopback must be dropped.
212 */
213 if ((ipv6_addr_loopback(&hdr->saddr) ||
214 ipv6_addr_loopback(&hdr->daddr)) &&
215 !(dev->flags & IFF_LOOPBACK) &&
216 !netif_is_l3_master(dev))
217 goto err;
218
219 /* RFC4291 Errata ID: 3480
220 * Interface-Local scope spans only a single interface on a
221 * node and is useful only for loopback transmission of
222 * multicast. Packets with interface-local scope received
223 * from another node must be discarded.
224 */
225 if (!(skb->pkt_type == PACKET_LOOPBACK ||
226 dev->flags & IFF_LOOPBACK) &&
227 ipv6_addr_is_multicast(&hdr->daddr) &&
228 IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 1)
229 goto err;
230
231 /* If enabled, drop unicast packets that were encapsulated in link-layer
232 * multicast or broadcast to protected against the so-called "hole-196"
233 * attack in 802.11 wireless.
234 */
235 if (!ipv6_addr_is_multicast(&hdr->daddr) &&
236 (skb->pkt_type == PACKET_BROADCAST ||
237 skb->pkt_type == PACKET_MULTICAST) &&
238 READ_ONCE(idev->cnf.drop_unicast_in_l2_multicast)) {
239 SKB_DR_SET(reason, UNICAST_IN_L2_MULTICAST);
240 goto err;
241 }
242
243 /* RFC4291 2.7
244 * Nodes must not originate a packet to a multicast address whose scope
245 * field contains the reserved value 0; if such a packet is received, it
246 * must be silently dropped.
247 */
248 if (ipv6_addr_is_multicast(&hdr->daddr) &&
249 IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 0)
250 goto err;
251
252 /*
253 * RFC4291 2.7
254 * Multicast addresses must not be used as source addresses in IPv6
255 * packets or appear in any Routing header.
256 */
257 if (ipv6_addr_is_multicast(&hdr->saddr))
258 goto err;
259
260 skb->transport_header = skb->network_header + sizeof(*hdr);
261 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
262
263 pkt_len = ntohs(hdr->payload_len);
264
265 /* pkt_len may be zero if Jumbo payload option is present */
266 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
267 if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
268 __IP6_INC_STATS(net,
269 idev, IPSTATS_MIB_INTRUNCATEDPKTS);
270 SKB_DR_SET(reason, PKT_TOO_SMALL);
271 goto drop;
272 }
273 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
274 goto err;
275 hdr = ipv6_hdr(skb);
276 }
277
278 if (hdr->nexthdr == NEXTHDR_HOP) {
279 if (ipv6_parse_hopopts(skb) < 0) {
280 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
281 rcu_read_unlock();
282 return NULL;
283 }
284 }
285
286 rcu_read_unlock();
287
288 /* Must drop socket now because of tproxy. */
289 if (!skb_sk_is_prefetched(skb))
290 skb_orphan(skb);
291
292 return skb;
293err:
294 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
295 SKB_DR_OR(reason, IP_INHDR);
296drop:
297 rcu_read_unlock();
298 kfree_skb_reason(skb, reason);
299 return NULL;
300}
301
302int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
303{
304 struct net *net = dev_net(skb->dev);
305
306 skb = ip6_rcv_core(skb, dev, net);
307 if (skb == NULL)
308 return NET_RX_DROP;
309 return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
310 net, NULL, skb, dev, NULL,
311 ip6_rcv_finish);
312}
313
314static void ip6_sublist_rcv(struct list_head *head, struct net_device *dev,
315 struct net *net)
316{
317 NF_HOOK_LIST(NFPROTO_IPV6, NF_INET_PRE_ROUTING, net, NULL,
318 head, dev, NULL, ip6_rcv_finish);
319 ip6_list_rcv_finish(net, NULL, head);
320}
321
322/* Receive a list of IPv6 packets */
323void ipv6_list_rcv(struct list_head *head, struct packet_type *pt,
324 struct net_device *orig_dev)
325{
326 struct net_device *curr_dev = NULL;
327 struct net *curr_net = NULL;
328 struct sk_buff *skb, *next;
329 LIST_HEAD(sublist);
330
331 list_for_each_entry_safe(skb, next, head, list) {
332 struct net_device *dev = skb->dev;
333 struct net *net = dev_net(dev);
334
335 skb_list_del_init(skb);
336 skb = ip6_rcv_core(skb, dev, net);
337 if (skb == NULL)
338 continue;
339
340 if (curr_dev != dev || curr_net != net) {
341 /* dispatch old sublist */
342 if (!list_empty(&sublist))
343 ip6_sublist_rcv(&sublist, curr_dev, curr_net);
344 /* start new sublist */
345 INIT_LIST_HEAD(&sublist);
346 curr_dev = dev;
347 curr_net = net;
348 }
349 list_add_tail(&skb->list, &sublist);
350 }
351 /* dispatch final sublist */
352 if (!list_empty(&sublist))
353 ip6_sublist_rcv(&sublist, curr_dev, curr_net);
354}
355
356INDIRECT_CALLABLE_DECLARE(int tcp_v6_rcv(struct sk_buff *));
357
358/*
359 * Deliver the packet to the host
360 */
361void ip6_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int nexthdr,
362 bool have_final)
363{
364 const struct inet6_protocol *ipprot;
365 struct inet6_dev *idev;
366 unsigned int nhoff;
367 SKB_DR(reason);
368 bool raw;
369
370 /*
371 * Parse extension headers
372 */
373
374resubmit:
375 idev = ip6_dst_idev(skb_dst(skb));
376 nhoff = IP6CB(skb)->nhoff;
377 if (!have_final) {
378 if (!pskb_pull(skb, skb_transport_offset(skb)))
379 goto discard;
380 nexthdr = skb_network_header(skb)[nhoff];
381 }
382
383resubmit_final:
384 raw = raw6_local_deliver(skb, nexthdr);
385 ipprot = rcu_dereference(inet6_protos[nexthdr]);
386 if (ipprot) {
387 int ret;
388
389 if (have_final) {
390 if (!(ipprot->flags & INET6_PROTO_FINAL)) {
391 /* Once we've seen a final protocol don't
392 * allow encapsulation on any non-final
393 * ones. This allows foo in UDP encapsulation
394 * to work.
395 */
396 goto discard;
397 }
398 } else if (ipprot->flags & INET6_PROTO_FINAL) {
399 const struct ipv6hdr *hdr;
400 int sdif = inet6_sdif(skb);
401 struct net_device *dev;
402
403 /* Only do this once for first final protocol */
404 have_final = true;
405
406
407 skb_postpull_rcsum(skb, skb_network_header(skb),
408 skb_network_header_len(skb));
409 hdr = ipv6_hdr(skb);
410
411 /* skb->dev passed may be master dev for vrfs. */
412 if (sdif) {
413 dev = dev_get_by_index_rcu(net, sdif);
414 if (!dev)
415 goto discard;
416 } else {
417 dev = skb->dev;
418 }
419
420 if (ipv6_addr_is_multicast(&hdr->daddr) &&
421 !ipv6_chk_mcast_addr(dev, &hdr->daddr,
422 &hdr->saddr) &&
423 !ipv6_is_mld(skb, nexthdr, skb_network_header_len(skb))) {
424 SKB_DR_SET(reason, IP_INADDRERRORS);
425 goto discard;
426 }
427 }
428 if (!(ipprot->flags & INET6_PROTO_NOPOLICY)) {
429 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
430 SKB_DR_SET(reason, XFRM_POLICY);
431 goto discard;
432 }
433 nf_reset_ct(skb);
434 }
435
436 ret = INDIRECT_CALL_2(ipprot->handler, tcp_v6_rcv, udpv6_rcv,
437 skb);
438 if (ret > 0) {
439 if (ipprot->flags & INET6_PROTO_FINAL) {
440 /* Not an extension header, most likely UDP
441 * encapsulation. Use return value as nexthdr
442 * protocol not nhoff (which presumably is
443 * not set by handler).
444 */
445 nexthdr = ret;
446 goto resubmit_final;
447 } else {
448 goto resubmit;
449 }
450 } else if (ret == 0) {
451 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
452 }
453 } else {
454 if (!raw) {
455 if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
456 __IP6_INC_STATS(net, idev,
457 IPSTATS_MIB_INUNKNOWNPROTOS);
458 icmpv6_send(skb, ICMPV6_PARAMPROB,
459 ICMPV6_UNK_NEXTHDR, nhoff);
460 SKB_DR_SET(reason, IP_NOPROTO);
461 } else {
462 SKB_DR_SET(reason, XFRM_POLICY);
463 }
464 kfree_skb_reason(skb, reason);
465 } else {
466 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
467 consume_skb(skb);
468 }
469 }
470 return;
471
472discard:
473 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
474 kfree_skb_reason(skb, reason);
475}
476
477static int ip6_input_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
478{
479 skb_clear_delivery_time(skb);
480 rcu_read_lock();
481 ip6_protocol_deliver_rcu(net, skb, 0, false);
482 rcu_read_unlock();
483
484 return 0;
485}
486
487
488int ip6_input(struct sk_buff *skb)
489{
490 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN,
491 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
492 ip6_input_finish);
493}
494EXPORT_SYMBOL_GPL(ip6_input);
495
496int ip6_mc_input(struct sk_buff *skb)
497{
498 int sdif = inet6_sdif(skb);
499 const struct ipv6hdr *hdr;
500 struct net_device *dev;
501 bool deliver;
502
503 __IP6_UPD_PO_STATS(dev_net(skb_dst(skb)->dev),
504 __in6_dev_get_safely(skb->dev), IPSTATS_MIB_INMCAST,
505 skb->len);
506
507 /* skb->dev passed may be master dev for vrfs. */
508 if (sdif) {
509 rcu_read_lock();
510 dev = dev_get_by_index_rcu(dev_net(skb->dev), sdif);
511 if (!dev) {
512 rcu_read_unlock();
513 kfree_skb(skb);
514 return -ENODEV;
515 }
516 } else {
517 dev = skb->dev;
518 }
519
520 hdr = ipv6_hdr(skb);
521 deliver = ipv6_chk_mcast_addr(dev, &hdr->daddr, NULL);
522 if (sdif)
523 rcu_read_unlock();
524
525#ifdef CONFIG_IPV6_MROUTE
526 /*
527 * IPv6 multicast router mode is now supported ;)
528 */
529 if (atomic_read(&dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding) &&
530 !(ipv6_addr_type(&hdr->daddr) &
531 (IPV6_ADDR_LOOPBACK|IPV6_ADDR_LINKLOCAL)) &&
532 likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
533 /*
534 * Okay, we try to forward - split and duplicate
535 * packets.
536 */
537 struct sk_buff *skb2;
538 struct inet6_skb_parm *opt = IP6CB(skb);
539
540 /* Check for MLD */
541 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
542 /* Check if this is a mld message */
543 u8 nexthdr = hdr->nexthdr;
544 __be16 frag_off;
545 int offset;
546
547 /* Check if the value of Router Alert
548 * is for MLD (0x0000).
549 */
550 if (opt->ra == htons(IPV6_OPT_ROUTERALERT_MLD)) {
551 deliver = false;
552
553 if (!ipv6_ext_hdr(nexthdr)) {
554 /* BUG */
555 goto out;
556 }
557 offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
558 &nexthdr, &frag_off);
559 if (offset < 0)
560 goto out;
561
562 if (ipv6_is_mld(skb, nexthdr, offset))
563 deliver = true;
564
565 goto out;
566 }
567 /* unknown RA - process it normally */
568 }
569
570 if (deliver)
571 skb2 = skb_clone(skb, GFP_ATOMIC);
572 else {
573 skb2 = skb;
574 skb = NULL;
575 }
576
577 if (skb2) {
578 ip6_mr_input(skb2);
579 }
580 }
581out:
582#endif
583 if (likely(deliver))
584 ip6_input(skb);
585 else {
586 /* discard */
587 kfree_skb(skb);
588 }
589
590 return 0;
591}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * IPv6 input
4 * Linux INET6 implementation
5 *
6 * Authors:
7 * Pedro Roque <roque@di.fc.ul.pt>
8 * Ian P. Morris <I.P.Morris@soton.ac.uk>
9 *
10 * Based in linux/net/ipv4/ip_input.c
11 */
12/* Changes
13 *
14 * Mitsuru KANDA @USAGI and
15 * YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs().
16 */
17
18#include <linux/errno.h>
19#include <linux/types.h>
20#include <linux/socket.h>
21#include <linux/sockios.h>
22#include <linux/net.h>
23#include <linux/netdevice.h>
24#include <linux/in6.h>
25#include <linux/icmpv6.h>
26#include <linux/mroute6.h>
27#include <linux/slab.h>
28#include <linux/indirect_call_wrapper.h>
29
30#include <linux/netfilter.h>
31#include <linux/netfilter_ipv6.h>
32
33#include <net/sock.h>
34#include <net/snmp.h>
35
36#include <net/ipv6.h>
37#include <net/protocol.h>
38#include <net/transp_v6.h>
39#include <net/rawv6.h>
40#include <net/ndisc.h>
41#include <net/ip6_route.h>
42#include <net/addrconf.h>
43#include <net/xfrm.h>
44#include <net/inet_ecn.h>
45#include <net/dst_metadata.h>
46
47INDIRECT_CALLABLE_DECLARE(void udp_v6_early_demux(struct sk_buff *));
48INDIRECT_CALLABLE_DECLARE(void tcp_v6_early_demux(struct sk_buff *));
49static void ip6_rcv_finish_core(struct net *net, struct sock *sk,
50 struct sk_buff *skb)
51{
52 void (*edemux)(struct sk_buff *skb);
53
54 if (net->ipv4.sysctl_ip_early_demux && !skb_dst(skb) && skb->sk == NULL) {
55 const struct inet6_protocol *ipprot;
56
57 ipprot = rcu_dereference(inet6_protos[ipv6_hdr(skb)->nexthdr]);
58 if (ipprot && (edemux = READ_ONCE(ipprot->early_demux)))
59 INDIRECT_CALL_2(edemux, tcp_v6_early_demux,
60 udp_v6_early_demux, skb);
61 }
62 if (!skb_valid_dst(skb))
63 ip6_route_input(skb);
64}
65
66int ip6_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
67{
68 /* if ingress device is enslaved to an L3 master device pass the
69 * skb to its handler for processing
70 */
71 skb = l3mdev_ip6_rcv(skb);
72 if (!skb)
73 return NET_RX_SUCCESS;
74 ip6_rcv_finish_core(net, sk, skb);
75
76 return dst_input(skb);
77}
78
79static void ip6_sublist_rcv_finish(struct list_head *head)
80{
81 struct sk_buff *skb, *next;
82
83 list_for_each_entry_safe(skb, next, head, list) {
84 skb_list_del_init(skb);
85 dst_input(skb);
86 }
87}
88
89static void ip6_list_rcv_finish(struct net *net, struct sock *sk,
90 struct list_head *head)
91{
92 struct dst_entry *curr_dst = NULL;
93 struct sk_buff *skb, *next;
94 struct list_head sublist;
95
96 INIT_LIST_HEAD(&sublist);
97 list_for_each_entry_safe(skb, next, head, list) {
98 struct dst_entry *dst;
99
100 skb_list_del_init(skb);
101 /* if ingress device is enslaved to an L3 master device pass the
102 * skb to its handler for processing
103 */
104 skb = l3mdev_ip6_rcv(skb);
105 if (!skb)
106 continue;
107 ip6_rcv_finish_core(net, sk, skb);
108 dst = skb_dst(skb);
109 if (curr_dst != dst) {
110 /* dispatch old sublist */
111 if (!list_empty(&sublist))
112 ip6_sublist_rcv_finish(&sublist);
113 /* start new sublist */
114 INIT_LIST_HEAD(&sublist);
115 curr_dst = dst;
116 }
117 list_add_tail(&skb->list, &sublist);
118 }
119 /* dispatch final sublist */
120 ip6_sublist_rcv_finish(&sublist);
121}
122
123static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
124 struct net *net)
125{
126 const struct ipv6hdr *hdr;
127 u32 pkt_len;
128 struct inet6_dev *idev;
129
130 if (skb->pkt_type == PACKET_OTHERHOST) {
131 kfree_skb(skb);
132 return NULL;
133 }
134
135 rcu_read_lock();
136
137 idev = __in6_dev_get(skb->dev);
138
139 __IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_IN, skb->len);
140
141 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
142 !idev || unlikely(idev->cnf.disable_ipv6)) {
143 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
144 goto drop;
145 }
146
147 memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
148
149 /*
150 * Store incoming device index. When the packet will
151 * be queued, we cannot refer to skb->dev anymore.
152 *
153 * BTW, when we send a packet for our own local address on a
154 * non-loopback interface (e.g. ethX), it is being delivered
155 * via the loopback interface (lo) here; skb->dev = loopback_dev.
156 * It, however, should be considered as if it is being
157 * arrived via the sending interface (ethX), because of the
158 * nature of scoping architecture. --yoshfuji
159 */
160 IP6CB(skb)->iif = skb_valid_dst(skb) ? ip6_dst_idev(skb_dst(skb))->dev->ifindex : dev->ifindex;
161
162 if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
163 goto err;
164
165 hdr = ipv6_hdr(skb);
166
167 if (hdr->version != 6)
168 goto err;
169
170 __IP6_ADD_STATS(net, idev,
171 IPSTATS_MIB_NOECTPKTS +
172 (ipv6_get_dsfield(hdr) & INET_ECN_MASK),
173 max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs));
174 /*
175 * RFC4291 2.5.3
176 * The loopback address must not be used as the source address in IPv6
177 * packets that are sent outside of a single node. [..]
178 * A packet received on an interface with a destination address
179 * of loopback must be dropped.
180 */
181 if ((ipv6_addr_loopback(&hdr->saddr) ||
182 ipv6_addr_loopback(&hdr->daddr)) &&
183 !(dev->flags & IFF_LOOPBACK) &&
184 !netif_is_l3_master(dev))
185 goto err;
186
187 /* RFC4291 Errata ID: 3480
188 * Interface-Local scope spans only a single interface on a
189 * node and is useful only for loopback transmission of
190 * multicast. Packets with interface-local scope received
191 * from another node must be discarded.
192 */
193 if (!(skb->pkt_type == PACKET_LOOPBACK ||
194 dev->flags & IFF_LOOPBACK) &&
195 ipv6_addr_is_multicast(&hdr->daddr) &&
196 IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 1)
197 goto err;
198
199 /* If enabled, drop unicast packets that were encapsulated in link-layer
200 * multicast or broadcast to protected against the so-called "hole-196"
201 * attack in 802.11 wireless.
202 */
203 if (!ipv6_addr_is_multicast(&hdr->daddr) &&
204 (skb->pkt_type == PACKET_BROADCAST ||
205 skb->pkt_type == PACKET_MULTICAST) &&
206 idev->cnf.drop_unicast_in_l2_multicast)
207 goto err;
208
209 /* RFC4291 2.7
210 * Nodes must not originate a packet to a multicast address whose scope
211 * field contains the reserved value 0; if such a packet is received, it
212 * must be silently dropped.
213 */
214 if (ipv6_addr_is_multicast(&hdr->daddr) &&
215 IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 0)
216 goto err;
217
218 /*
219 * RFC4291 2.7
220 * Multicast addresses must not be used as source addresses in IPv6
221 * packets or appear in any Routing header.
222 */
223 if (ipv6_addr_is_multicast(&hdr->saddr))
224 goto err;
225
226 /* While RFC4291 is not explicit about v4mapped addresses
227 * in IPv6 headers, it seems clear linux dual-stack
228 * model can not deal properly with these.
229 * Security models could be fooled by ::ffff:127.0.0.1 for example.
230 *
231 * https://tools.ietf.org/html/draft-itojun-v6ops-v4mapped-harmful-02
232 */
233 if (ipv6_addr_v4mapped(&hdr->saddr))
234 goto err;
235
236 skb->transport_header = skb->network_header + sizeof(*hdr);
237 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
238
239 pkt_len = ntohs(hdr->payload_len);
240
241 /* pkt_len may be zero if Jumbo payload option is present */
242 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
243 if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
244 __IP6_INC_STATS(net,
245 idev, IPSTATS_MIB_INTRUNCATEDPKTS);
246 goto drop;
247 }
248 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
249 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
250 goto drop;
251 }
252 hdr = ipv6_hdr(skb);
253 }
254
255 if (hdr->nexthdr == NEXTHDR_HOP) {
256 if (ipv6_parse_hopopts(skb) < 0) {
257 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
258 rcu_read_unlock();
259 return NULL;
260 }
261 }
262
263 rcu_read_unlock();
264
265 /* Must drop socket now because of tproxy. */
266 skb_orphan(skb);
267
268 return skb;
269err:
270 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
271drop:
272 rcu_read_unlock();
273 kfree_skb(skb);
274 return NULL;
275}
276
277int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
278{
279 struct net *net = dev_net(skb->dev);
280
281 skb = ip6_rcv_core(skb, dev, net);
282 if (skb == NULL)
283 return NET_RX_DROP;
284 return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
285 net, NULL, skb, dev, NULL,
286 ip6_rcv_finish);
287}
288
289static void ip6_sublist_rcv(struct list_head *head, struct net_device *dev,
290 struct net *net)
291{
292 NF_HOOK_LIST(NFPROTO_IPV6, NF_INET_PRE_ROUTING, net, NULL,
293 head, dev, NULL, ip6_rcv_finish);
294 ip6_list_rcv_finish(net, NULL, head);
295}
296
297/* Receive a list of IPv6 packets */
298void ipv6_list_rcv(struct list_head *head, struct packet_type *pt,
299 struct net_device *orig_dev)
300{
301 struct net_device *curr_dev = NULL;
302 struct net *curr_net = NULL;
303 struct sk_buff *skb, *next;
304 struct list_head sublist;
305
306 INIT_LIST_HEAD(&sublist);
307 list_for_each_entry_safe(skb, next, head, list) {
308 struct net_device *dev = skb->dev;
309 struct net *net = dev_net(dev);
310
311 skb_list_del_init(skb);
312 skb = ip6_rcv_core(skb, dev, net);
313 if (skb == NULL)
314 continue;
315
316 if (curr_dev != dev || curr_net != net) {
317 /* dispatch old sublist */
318 if (!list_empty(&sublist))
319 ip6_sublist_rcv(&sublist, curr_dev, curr_net);
320 /* start new sublist */
321 INIT_LIST_HEAD(&sublist);
322 curr_dev = dev;
323 curr_net = net;
324 }
325 list_add_tail(&skb->list, &sublist);
326 }
327 /* dispatch final sublist */
328 ip6_sublist_rcv(&sublist, curr_dev, curr_net);
329}
330
331INDIRECT_CALLABLE_DECLARE(int udpv6_rcv(struct sk_buff *));
332INDIRECT_CALLABLE_DECLARE(int tcp_v6_rcv(struct sk_buff *));
333
334/*
335 * Deliver the packet to the host
336 */
337void ip6_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int nexthdr,
338 bool have_final)
339{
340 const struct inet6_protocol *ipprot;
341 struct inet6_dev *idev;
342 unsigned int nhoff;
343 bool raw;
344
345 /*
346 * Parse extension headers
347 */
348
349resubmit:
350 idev = ip6_dst_idev(skb_dst(skb));
351 nhoff = IP6CB(skb)->nhoff;
352 if (!have_final) {
353 if (!pskb_pull(skb, skb_transport_offset(skb)))
354 goto discard;
355 nexthdr = skb_network_header(skb)[nhoff];
356 }
357
358resubmit_final:
359 raw = raw6_local_deliver(skb, nexthdr);
360 ipprot = rcu_dereference(inet6_protos[nexthdr]);
361 if (ipprot) {
362 int ret;
363
364 if (have_final) {
365 if (!(ipprot->flags & INET6_PROTO_FINAL)) {
366 /* Once we've seen a final protocol don't
367 * allow encapsulation on any non-final
368 * ones. This allows foo in UDP encapsulation
369 * to work.
370 */
371 goto discard;
372 }
373 } else if (ipprot->flags & INET6_PROTO_FINAL) {
374 const struct ipv6hdr *hdr;
375 int sdif = inet6_sdif(skb);
376 struct net_device *dev;
377
378 /* Only do this once for first final protocol */
379 have_final = true;
380
381 /* Free reference early: we don't need it any more,
382 and it may hold ip_conntrack module loaded
383 indefinitely. */
384 nf_reset_ct(skb);
385
386 skb_postpull_rcsum(skb, skb_network_header(skb),
387 skb_network_header_len(skb));
388 hdr = ipv6_hdr(skb);
389
390 /* skb->dev passed may be master dev for vrfs. */
391 if (sdif) {
392 dev = dev_get_by_index_rcu(net, sdif);
393 if (!dev)
394 goto discard;
395 } else {
396 dev = skb->dev;
397 }
398
399 if (ipv6_addr_is_multicast(&hdr->daddr) &&
400 !ipv6_chk_mcast_addr(dev, &hdr->daddr,
401 &hdr->saddr) &&
402 !ipv6_is_mld(skb, nexthdr, skb_network_header_len(skb)))
403 goto discard;
404 }
405 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
406 !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
407 goto discard;
408
409 ret = INDIRECT_CALL_2(ipprot->handler, tcp_v6_rcv, udpv6_rcv,
410 skb);
411 if (ret > 0) {
412 if (ipprot->flags & INET6_PROTO_FINAL) {
413 /* Not an extension header, most likely UDP
414 * encapsulation. Use return value as nexthdr
415 * protocol not nhoff (which presumably is
416 * not set by handler).
417 */
418 nexthdr = ret;
419 goto resubmit_final;
420 } else {
421 goto resubmit;
422 }
423 } else if (ret == 0) {
424 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
425 }
426 } else {
427 if (!raw) {
428 if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
429 __IP6_INC_STATS(net, idev,
430 IPSTATS_MIB_INUNKNOWNPROTOS);
431 icmpv6_send(skb, ICMPV6_PARAMPROB,
432 ICMPV6_UNK_NEXTHDR, nhoff);
433 }
434 kfree_skb(skb);
435 } else {
436 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
437 consume_skb(skb);
438 }
439 }
440 return;
441
442discard:
443 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
444 kfree_skb(skb);
445}
446
447static int ip6_input_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
448{
449 rcu_read_lock();
450 ip6_protocol_deliver_rcu(net, skb, 0, false);
451 rcu_read_unlock();
452
453 return 0;
454}
455
456
457int ip6_input(struct sk_buff *skb)
458{
459 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN,
460 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
461 ip6_input_finish);
462}
463EXPORT_SYMBOL_GPL(ip6_input);
464
465int ip6_mc_input(struct sk_buff *skb)
466{
467 int sdif = inet6_sdif(skb);
468 const struct ipv6hdr *hdr;
469 struct net_device *dev;
470 bool deliver;
471
472 __IP6_UPD_PO_STATS(dev_net(skb_dst(skb)->dev),
473 __in6_dev_get_safely(skb->dev), IPSTATS_MIB_INMCAST,
474 skb->len);
475
476 /* skb->dev passed may be master dev for vrfs. */
477 if (sdif) {
478 rcu_read_lock();
479 dev = dev_get_by_index_rcu(dev_net(skb->dev), sdif);
480 if (!dev) {
481 rcu_read_unlock();
482 kfree_skb(skb);
483 return -ENODEV;
484 }
485 } else {
486 dev = skb->dev;
487 }
488
489 hdr = ipv6_hdr(skb);
490 deliver = ipv6_chk_mcast_addr(dev, &hdr->daddr, NULL);
491 if (sdif)
492 rcu_read_unlock();
493
494#ifdef CONFIG_IPV6_MROUTE
495 /*
496 * IPv6 multicast router mode is now supported ;)
497 */
498 if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding &&
499 !(ipv6_addr_type(&hdr->daddr) &
500 (IPV6_ADDR_LOOPBACK|IPV6_ADDR_LINKLOCAL)) &&
501 likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
502 /*
503 * Okay, we try to forward - split and duplicate
504 * packets.
505 */
506 struct sk_buff *skb2;
507 struct inet6_skb_parm *opt = IP6CB(skb);
508
509 /* Check for MLD */
510 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
511 /* Check if this is a mld message */
512 u8 nexthdr = hdr->nexthdr;
513 __be16 frag_off;
514 int offset;
515
516 /* Check if the value of Router Alert
517 * is for MLD (0x0000).
518 */
519 if (opt->ra == htons(IPV6_OPT_ROUTERALERT_MLD)) {
520 deliver = false;
521
522 if (!ipv6_ext_hdr(nexthdr)) {
523 /* BUG */
524 goto out;
525 }
526 offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
527 &nexthdr, &frag_off);
528 if (offset < 0)
529 goto out;
530
531 if (ipv6_is_mld(skb, nexthdr, offset))
532 deliver = true;
533
534 goto out;
535 }
536 /* unknown RA - process it normally */
537 }
538
539 if (deliver)
540 skb2 = skb_clone(skb, GFP_ATOMIC);
541 else {
542 skb2 = skb;
543 skb = NULL;
544 }
545
546 if (skb2) {
547 ip6_mr_input(skb2);
548 }
549 }
550out:
551#endif
552 if (likely(deliver))
553 ip6_input(skb);
554 else {
555 /* discard */
556 kfree_skb(skb);
557 }
558
559 return 0;
560}