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