Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
[linux-2.6] / 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
32 #include <linux/netfilter.h>
33 #include <linux/netfilter_ipv6.h>
34
35 #include <net/sock.h>
36 #include <net/snmp.h>
37
38 #include <net/ipv6.h>
39 #include <net/protocol.h>
40 #include <net/transp_v6.h>
41 #include <net/rawv6.h>
42 #include <net/ndisc.h>
43 #include <net/ip6_route.h>
44 #include <net/addrconf.h>
45 #include <net/xfrm.h>
46
47
48
49 inline int ip6_rcv_finish( struct sk_buff *skb)
50 {
51         if (skb->dst == NULL)
52                 ip6_route_input(skb);
53
54         return dst_input(skb);
55 }
56
57 int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
58 {
59         struct ipv6hdr *hdr;
60         u32             pkt_len;
61         struct inet6_dev *idev;
62         struct net *net = dev_net(skb->dev);
63
64         if (skb->pkt_type == PACKET_OTHERHOST) {
65                 kfree_skb(skb);
66                 return 0;
67         }
68
69         rcu_read_lock();
70
71         idev = __in6_dev_get(skb->dev);
72
73         IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INRECEIVES);
74
75         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
76             !idev || unlikely(idev->cnf.disable_ipv6)) {
77                 IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS);
78                 rcu_read_unlock();
79                 goto out;
80         }
81
82         memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
83
84         /*
85          * Store incoming device index. When the packet will
86          * be queued, we cannot refer to skb->dev anymore.
87          *
88          * BTW, when we send a packet for our own local address on a
89          * non-loopback interface (e.g. ethX), it is being delivered
90          * via the loopback interface (lo) here; skb->dev = loopback_dev.
91          * It, however, should be considered as if it is being
92          * arrived via the sending interface (ethX), because of the
93          * nature of scoping architecture. --yoshfuji
94          */
95         IP6CB(skb)->iif = skb->dst ? ip6_dst_idev(skb->dst)->dev->ifindex : dev->ifindex;
96
97         if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
98                 goto err;
99
100         hdr = ipv6_hdr(skb);
101
102         if (hdr->version != 6)
103                 goto err;
104
105         /*
106          * RFC4291 2.5.3
107          * A packet received on an interface with a destination address
108          * of loopback must be dropped.
109          */
110         if (!(dev->flags & IFF_LOOPBACK) &&
111             ipv6_addr_loopback(&hdr->daddr))
112                 goto err;
113
114         skb->transport_header = skb->network_header + sizeof(*hdr);
115         IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
116
117         pkt_len = ntohs(hdr->payload_len);
118
119         /* pkt_len may be zero if Jumbo payload option is present */
120         if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
121                 if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
122                         IP6_INC_STATS_BH(net,
123                                          idev, IPSTATS_MIB_INTRUNCATEDPKTS);
124                         goto drop;
125                 }
126                 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
127                         IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS);
128                         goto drop;
129                 }
130                 hdr = ipv6_hdr(skb);
131         }
132
133         if (hdr->nexthdr == NEXTHDR_HOP) {
134                 if (ipv6_parse_hopopts(skb) < 0) {
135                         IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS);
136                         rcu_read_unlock();
137                         return 0;
138                 }
139         }
140
141         rcu_read_unlock();
142
143         return NF_HOOK(PF_INET6, NF_INET_PRE_ROUTING, skb, dev, NULL,
144                        ip6_rcv_finish);
145 err:
146         IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS);
147 drop:
148         rcu_read_unlock();
149         kfree_skb(skb);
150 out:
151         return 0;
152 }
153
154 /*
155  *      Deliver the packet to the host
156  */
157
158
159 static int ip6_input_finish(struct sk_buff *skb)
160 {
161         struct inet6_protocol *ipprot;
162         unsigned int nhoff;
163         int nexthdr, raw;
164         u8 hash;
165         struct inet6_dev *idev;
166         struct net *net = dev_net(skb->dst->dev);
167
168         /*
169          *      Parse extension headers
170          */
171
172         rcu_read_lock();
173 resubmit:
174         idev = ip6_dst_idev(skb->dst);
175         if (!pskb_pull(skb, skb_transport_offset(skb)))
176                 goto discard;
177         nhoff = IP6CB(skb)->nhoff;
178         nexthdr = skb_network_header(skb)[nhoff];
179
180         raw = raw6_local_deliver(skb, nexthdr);
181
182         hash = nexthdr & (MAX_INET_PROTOS - 1);
183         if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) {
184                 int ret;
185
186                 if (ipprot->flags & INET6_PROTO_FINAL) {
187                         struct ipv6hdr *hdr;
188
189                         /* Free reference early: we don't need it any more,
190                            and it may hold ip_conntrack module loaded
191                            indefinitely. */
192                         nf_reset(skb);
193
194                         skb_postpull_rcsum(skb, skb_network_header(skb),
195                                            skb_network_header_len(skb));
196                         hdr = ipv6_hdr(skb);
197                         if (ipv6_addr_is_multicast(&hdr->daddr) &&
198                             !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
199                             &hdr->saddr) &&
200                             !ipv6_is_mld(skb, nexthdr))
201                                 goto discard;
202                 }
203                 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
204                     !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
205                         goto discard;
206
207                 ret = ipprot->handler(skb);
208                 if (ret > 0)
209                         goto resubmit;
210                 else if (ret == 0)
211                         IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS);
212         } else {
213                 if (!raw) {
214                         if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
215                                 IP6_INC_STATS_BH(net, idev,
216                                                  IPSTATS_MIB_INUNKNOWNPROTOS);
217                                 icmpv6_send(skb, ICMPV6_PARAMPROB,
218                                             ICMPV6_UNK_NEXTHDR, nhoff,
219                                             skb->dev);
220                         }
221                 } else
222                         IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS);
223                 kfree_skb(skb);
224         }
225         rcu_read_unlock();
226         return 0;
227
228 discard:
229         IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS);
230         rcu_read_unlock();
231         kfree_skb(skb);
232         return 0;
233 }
234
235
236 int ip6_input(struct sk_buff *skb)
237 {
238         return NF_HOOK(PF_INET6, NF_INET_LOCAL_IN, skb, skb->dev, NULL,
239                        ip6_input_finish);
240 }
241
242 int ip6_mc_input(struct sk_buff *skb)
243 {
244         struct ipv6hdr *hdr;
245         int deliver;
246
247         IP6_INC_STATS_BH(dev_net(skb->dst->dev),
248                          ip6_dst_idev(skb->dst), IPSTATS_MIB_INMCASTPKTS);
249
250         hdr = ipv6_hdr(skb);
251         deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
252
253 #ifdef CONFIG_IPV6_MROUTE
254         /*
255          *      IPv6 multicast router mode is now supported ;)
256          */
257         if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding &&
258             likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
259                 /*
260                  * Okay, we try to forward - split and duplicate
261                  * packets.
262                  */
263                 struct sk_buff *skb2;
264                 struct inet6_skb_parm *opt = IP6CB(skb);
265
266                 /* Check for MLD */
267                 if (unlikely(opt->ra)) {
268                         /* Check if this is a mld message */
269                         u8 *ptr = skb_network_header(skb) + opt->ra;
270                         struct icmp6hdr *icmp6;
271                         u8 nexthdr = hdr->nexthdr;
272                         int offset;
273
274                         /* Check if the value of Router Alert
275                          * is for MLD (0x0000).
276                          */
277                         if ((ptr[2] | ptr[3]) == 0) {
278                                 deliver = 0;
279
280                                 if (!ipv6_ext_hdr(nexthdr)) {
281                                         /* BUG */
282                                         goto out;
283                                 }
284                                 offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
285                                                           &nexthdr);
286                                 if (offset < 0)
287                                         goto out;
288
289                                 if (nexthdr != IPPROTO_ICMPV6)
290                                         goto out;
291
292                                 if (!pskb_may_pull(skb, (skb_network_header(skb) +
293                                                    offset + 1 - skb->data)))
294                                         goto out;
295
296                                 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
297
298                                 switch (icmp6->icmp6_type) {
299                                 case ICMPV6_MGM_QUERY:
300                                 case ICMPV6_MGM_REPORT:
301                                 case ICMPV6_MGM_REDUCTION:
302                                 case ICMPV6_MLD2_REPORT:
303                                         deliver = 1;
304                                         break;
305                                 }
306                                 goto out;
307                         }
308                         /* unknown RA - process it normally */
309                 }
310
311                 if (deliver)
312                         skb2 = skb_clone(skb, GFP_ATOMIC);
313                 else {
314                         skb2 = skb;
315                         skb = NULL;
316                 }
317
318                 if (skb2) {
319                         skb2->dev = skb2->dst->dev;
320                         ip6_mr_input(skb2);
321                 }
322         }
323 out:
324 #endif
325         if (likely(deliver))
326                 ip6_input(skb);
327         else {
328                 /* discard */
329                 kfree_skb(skb);
330         }
331
332         return 0;
333 }