Merge branch 'master' of git://1984.lsi.us.es/nf-next
[linux-3.10.git] / net / ipv6 / ip6_input.c
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
48
49
50 int ip6_rcv_finish(struct sk_buff *skb)
51 {
52         if (sysctl_ip_early_demux && !skb_dst(skb)) {
53                 const struct inet6_protocol *ipprot;
54
55                 ipprot = rcu_dereference(inet6_protos[ipv6_hdr(skb)->nexthdr]);
56                 if (ipprot && ipprot->early_demux)
57                         ipprot->early_demux(skb);
58         }
59         if (!skb_dst(skb))
60                 ip6_route_input(skb);
61
62         return dst_input(skb);
63 }
64
65 int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
66 {
67         const struct ipv6hdr *hdr;
68         u32             pkt_len;
69         struct inet6_dev *idev;
70         struct net *net = dev_net(skb->dev);
71
72         if (skb->pkt_type == PACKET_OTHERHOST) {
73                 kfree_skb(skb);
74                 return NET_RX_DROP;
75         }
76
77         rcu_read_lock();
78
79         idev = __in6_dev_get(skb->dev);
80
81         IP6_UPD_PO_STATS_BH(net, idev, IPSTATS_MIB_IN, skb->len);
82
83         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
84             !idev || unlikely(idev->cnf.disable_ipv6)) {
85                 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS);
86                 goto drop;
87         }
88
89         memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
90
91         /*
92          * Store incoming device index. When the packet will
93          * be queued, we cannot refer to skb->dev anymore.
94          *
95          * BTW, when we send a packet for our own local address on a
96          * non-loopback interface (e.g. ethX), it is being delivered
97          * via the loopback interface (lo) here; skb->dev = loopback_dev.
98          * It, however, should be considered as if it is being
99          * arrived via the sending interface (ethX), because of the
100          * nature of scoping architecture. --yoshfuji
101          */
102         IP6CB(skb)->iif = skb_dst(skb) ? ip6_dst_idev(skb_dst(skb))->dev->ifindex : dev->ifindex;
103
104         if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
105                 goto err;
106
107         hdr = ipv6_hdr(skb);
108
109         if (hdr->version != 6)
110                 goto err;
111
112         /*
113          * RFC4291 2.5.3
114          * A packet received on an interface with a destination address
115          * of loopback must be dropped.
116          */
117         if (!(dev->flags & IFF_LOOPBACK) &&
118             ipv6_addr_loopback(&hdr->daddr))
119                 goto err;
120
121         /* RFC4291 2.7
122          * Nodes must not originate a packet to a multicast address whose scope
123          * field contains the reserved value 0; if such a packet is received, it
124          * must be silently dropped.
125          */
126         if (ipv6_addr_is_multicast(&hdr->daddr) &&
127             IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 0)
128                 goto err;
129
130         /*
131          * RFC4291 2.7
132          * Multicast addresses must not be used as source addresses in IPv6
133          * packets or appear in any Routing header.
134          */
135         if (ipv6_addr_is_multicast(&hdr->saddr))
136                 goto err;
137
138         skb->transport_header = skb->network_header + sizeof(*hdr);
139         IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
140
141         pkt_len = ntohs(hdr->payload_len);
142
143         /* pkt_len may be zero if Jumbo payload option is present */
144         if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
145                 if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
146                         IP6_INC_STATS_BH(net,
147                                          idev, IPSTATS_MIB_INTRUNCATEDPKTS);
148                         goto drop;
149                 }
150                 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
151                         IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS);
152                         goto drop;
153                 }
154                 hdr = ipv6_hdr(skb);
155         }
156
157         if (hdr->nexthdr == NEXTHDR_HOP) {
158                 if (ipv6_parse_hopopts(skb) < 0) {
159                         IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS);
160                         rcu_read_unlock();
161                         return NET_RX_DROP;
162                 }
163         }
164
165         rcu_read_unlock();
166
167         /* Must drop socket now because of tproxy. */
168         skb_orphan(skb);
169
170         return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, skb, dev, NULL,
171                        ip6_rcv_finish);
172 err:
173         IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS);
174 drop:
175         rcu_read_unlock();
176         kfree_skb(skb);
177         return NET_RX_DROP;
178 }
179
180 /*
181  *      Deliver the packet to the host
182  */
183
184
185 static int ip6_input_finish(struct sk_buff *skb)
186 {
187         struct net *net = dev_net(skb_dst(skb)->dev);
188         const struct inet6_protocol *ipprot;
189         struct inet6_dev *idev;
190         unsigned int nhoff;
191         int nexthdr;
192         bool raw;
193
194         /*
195          *      Parse extension headers
196          */
197
198         rcu_read_lock();
199 resubmit:
200         idev = ip6_dst_idev(skb_dst(skb));
201         if (!pskb_pull(skb, skb_transport_offset(skb)))
202                 goto discard;
203         nhoff = IP6CB(skb)->nhoff;
204         nexthdr = skb_network_header(skb)[nhoff];
205
206         raw = raw6_local_deliver(skb, nexthdr);
207         if ((ipprot = rcu_dereference(inet6_protos[nexthdr])) != NULL) {
208                 int ret;
209
210                 if (ipprot->flags & INET6_PROTO_FINAL) {
211                         const struct ipv6hdr *hdr;
212
213                         /* Free reference early: we don't need it any more,
214                            and it may hold ip_conntrack module loaded
215                            indefinitely. */
216                         nf_reset(skb);
217
218                         skb_postpull_rcsum(skb, skb_network_header(skb),
219                                            skb_network_header_len(skb));
220                         hdr = ipv6_hdr(skb);
221                         if (ipv6_addr_is_multicast(&hdr->daddr) &&
222                             !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
223                             &hdr->saddr) &&
224                             !ipv6_is_mld(skb, nexthdr, skb_network_header_len(skb)))
225                                 goto discard;
226                 }
227                 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
228                     !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
229                         goto discard;
230
231                 ret = ipprot->handler(skb);
232                 if (ret > 0)
233                         goto resubmit;
234                 else if (ret == 0)
235                         IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS);
236         } else {
237                 if (!raw) {
238                         if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
239                                 IP6_INC_STATS_BH(net, idev,
240                                                  IPSTATS_MIB_INUNKNOWNPROTOS);
241                                 icmpv6_send(skb, ICMPV6_PARAMPROB,
242                                             ICMPV6_UNK_NEXTHDR, nhoff);
243                         }
244                         kfree_skb(skb);
245                 } else {
246                         IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS);
247                         consume_skb(skb);
248                 }
249         }
250         rcu_read_unlock();
251         return 0;
252
253 discard:
254         IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS);
255         rcu_read_unlock();
256         kfree_skb(skb);
257         return 0;
258 }
259
260
261 int ip6_input(struct sk_buff *skb)
262 {
263         return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN, skb, skb->dev, NULL,
264                        ip6_input_finish);
265 }
266
267 int ip6_mc_input(struct sk_buff *skb)
268 {
269         const struct ipv6hdr *hdr;
270         bool deliver;
271
272         IP6_UPD_PO_STATS_BH(dev_net(skb_dst(skb)->dev),
273                          ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INMCAST,
274                          skb->len);
275
276         hdr = ipv6_hdr(skb);
277         deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
278
279 #ifdef CONFIG_IPV6_MROUTE
280         /*
281          *      IPv6 multicast router mode is now supported ;)
282          */
283         if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding &&
284             !(ipv6_addr_type(&hdr->daddr) &
285               (IPV6_ADDR_LOOPBACK|IPV6_ADDR_LINKLOCAL)) &&
286             likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
287                 /*
288                  * Okay, we try to forward - split and duplicate
289                  * packets.
290                  */
291                 struct sk_buff *skb2;
292                 struct inet6_skb_parm *opt = IP6CB(skb);
293
294                 /* Check for MLD */
295                 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
296                         /* Check if this is a mld message */
297                         u8 nexthdr = hdr->nexthdr;
298                         __be16 frag_off;
299                         int offset;
300
301                         /* Check if the value of Router Alert
302                          * is for MLD (0x0000).
303                          */
304                         if (opt->ra == htons(IPV6_OPT_ROUTERALERT_MLD)) {
305                                 deliver = false;
306
307                                 if (!ipv6_ext_hdr(nexthdr)) {
308                                         /* BUG */
309                                         goto out;
310                                 }
311                                 offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
312                                                           &nexthdr, &frag_off);
313                                 if (offset < 0)
314                                         goto out;
315
316                                 if (!ipv6_is_mld(skb, nexthdr, offset))
317                                         goto out;
318
319                                 deliver = true;
320                         }
321                         /* unknown RA - process it normally */
322                 }
323
324                 if (deliver)
325                         skb2 = skb_clone(skb, GFP_ATOMIC);
326                 else {
327                         skb2 = skb;
328                         skb = NULL;
329                 }
330
331                 if (skb2) {
332                         ip6_mr_input(skb2);
333                 }
334         }
335 out:
336 #endif
337         if (likely(deliver))
338                 ip6_input(skb);
339         else {
340                 /* discard */
341                 kfree_skb(skb);
342         }
343
344         return 0;
345 }