Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/chrisw...
[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  *      $Id: ip6_input.c,v 1.19 2000/12/13 18:31:50 davem Exp $
10  *
11  *      Based in linux/net/ipv4/ip_input.c
12  *
13  *      This program is free software; you can redistribute it and/or
14  *      modify it under the terms of the GNU General Public License
15  *      as published by the Free Software Foundation; either version
16  *      2 of the License, or (at your option) any later version.
17  */
18 /* Changes
19  *
20  *      Mitsuru KANDA @USAGI and
21  *      YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs().
22  */
23
24 #include <linux/errno.h>
25 #include <linux/types.h>
26 #include <linux/socket.h>
27 #include <linux/sockios.h>
28 #include <linux/net.h>
29 #include <linux/netdevice.h>
30 #include <linux/in6.h>
31 #include <linux/icmpv6.h>
32 #include <linux/mroute6.h>
33
34 #include <linux/netfilter.h>
35 #include <linux/netfilter_ipv6.h>
36
37 #include <net/sock.h>
38 #include <net/snmp.h>
39
40 #include <net/ipv6.h>
41 #include <net/protocol.h>
42 #include <net/transp_v6.h>
43 #include <net/rawv6.h>
44 #include <net/ndisc.h>
45 #include <net/ip6_route.h>
46 #include <net/addrconf.h>
47 #include <net/xfrm.h>
48
49
50
51 inline int ip6_rcv_finish( struct sk_buff *skb)
52 {
53         if (skb->dst == NULL)
54                 ip6_route_input(skb);
55
56         return dst_input(skb);
57 }
58
59 int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
60 {
61         struct ipv6hdr *hdr;
62         u32             pkt_len;
63         struct inet6_dev *idev;
64
65         if (skb->pkt_type == PACKET_OTHERHOST) {
66                 kfree_skb(skb);
67                 return 0;
68         }
69
70         rcu_read_lock();
71
72         idev = __in6_dev_get(skb->dev);
73
74         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INRECEIVES);
75
76         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
77                 IP6_INC_STATS_BH(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         skb->transport_header = skb->network_header + sizeof(*hdr);
106         IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
107
108         pkt_len = ntohs(hdr->payload_len);
109
110         /* pkt_len may be zero if Jumbo payload option is present */
111         if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
112                 if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
113                         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INTRUNCATEDPKTS);
114                         goto drop;
115                 }
116                 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
117                         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
118                         goto drop;
119                 }
120                 hdr = ipv6_hdr(skb);
121         }
122
123         if (hdr->nexthdr == NEXTHDR_HOP) {
124                 if (ipv6_parse_hopopts(skb) < 0) {
125                         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
126                         rcu_read_unlock();
127                         return 0;
128                 }
129         }
130
131         rcu_read_unlock();
132
133         return NF_HOOK(PF_INET6, NF_INET_PRE_ROUTING, skb, dev, NULL,
134                        ip6_rcv_finish);
135 err:
136         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
137 drop:
138         rcu_read_unlock();
139         kfree_skb(skb);
140 out:
141         return 0;
142 }
143
144 /*
145  *      Deliver the packet to the host
146  */
147
148
149 static int ip6_input_finish(struct sk_buff *skb)
150 {
151         struct inet6_protocol *ipprot;
152         unsigned int nhoff;
153         int nexthdr, raw;
154         u8 hash;
155         struct inet6_dev *idev;
156
157         /*
158          *      Parse extension headers
159          */
160
161         rcu_read_lock();
162 resubmit:
163         idev = ip6_dst_idev(skb->dst);
164         if (!pskb_pull(skb, skb_transport_offset(skb)))
165                 goto discard;
166         nhoff = IP6CB(skb)->nhoff;
167         nexthdr = skb_network_header(skb)[nhoff];
168
169         raw = raw6_local_deliver(skb, nexthdr);
170
171         hash = nexthdr & (MAX_INET_PROTOS - 1);
172         if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) {
173                 int ret;
174
175                 if (ipprot->flags & INET6_PROTO_FINAL) {
176                         struct ipv6hdr *hdr;
177
178                         /* Free reference early: we don't need it any more,
179                            and it may hold ip_conntrack module loaded
180                            indefinitely. */
181                         nf_reset(skb);
182
183                         skb_postpull_rcsum(skb, skb_network_header(skb),
184                                            skb_network_header_len(skb));
185                         hdr = ipv6_hdr(skb);
186                         if (ipv6_addr_is_multicast(&hdr->daddr) &&
187                             !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
188                             &hdr->saddr) &&
189                             !ipv6_is_mld(skb, nexthdr))
190                                 goto discard;
191                 }
192                 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
193                     !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
194                         goto discard;
195
196                 ret = ipprot->handler(skb);
197                 if (ret > 0)
198                         goto resubmit;
199                 else if (ret == 0)
200                         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS);
201         } else {
202                 if (!raw) {
203                         if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
204                                 IP6_INC_STATS_BH(idev, IPSTATS_MIB_INUNKNOWNPROTOS);
205                                 icmpv6_send(skb, ICMPV6_PARAMPROB,
206                                             ICMPV6_UNK_NEXTHDR, nhoff,
207                                             skb->dev);
208                         }
209                 } else
210                         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS);
211                 kfree_skb(skb);
212         }
213         rcu_read_unlock();
214         return 0;
215
216 discard:
217         IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS);
218         rcu_read_unlock();
219         kfree_skb(skb);
220         return 0;
221 }
222
223
224 int ip6_input(struct sk_buff *skb)
225 {
226         return NF_HOOK(PF_INET6, NF_INET_LOCAL_IN, skb, skb->dev, NULL,
227                        ip6_input_finish);
228 }
229
230 int ip6_mc_input(struct sk_buff *skb)
231 {
232         struct ipv6hdr *hdr;
233         int deliver;
234
235         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INMCASTPKTS);
236
237         hdr = ipv6_hdr(skb);
238         deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
239
240 #ifdef CONFIG_IPV6_MROUTE
241         /*
242          *      IPv6 multicast router mode is now supported ;)
243          */
244         if (ipv6_devconf.mc_forwarding &&
245             likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
246                 /*
247                  * Okay, we try to forward - split and duplicate
248                  * packets.
249                  */
250                 struct sk_buff *skb2;
251                 struct inet6_skb_parm *opt = IP6CB(skb);
252
253                 /* Check for MLD */
254                 if (unlikely(opt->ra)) {
255                         /* Check if this is a mld message */
256                         u8 *ptr = skb_network_header(skb) + opt->ra;
257                         struct icmp6hdr *icmp6;
258                         u8 nexthdr = hdr->nexthdr;
259                         int offset;
260
261                         /* Check if the value of Router Alert
262                          * is for MLD (0x0000).
263                          */
264                         if ((ptr[2] | ptr[3]) == 0) {
265                                 deliver = 0;
266
267                                 if (!ipv6_ext_hdr(nexthdr)) {
268                                         /* BUG */
269                                         goto out;
270                                 }
271                                 offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
272                                                           &nexthdr);
273                                 if (offset < 0)
274                                         goto out;
275
276                                 if (nexthdr != IPPROTO_ICMPV6)
277                                         goto out;
278
279                                 if (!pskb_may_pull(skb, (skb_network_header(skb) +
280                                                    offset + 1 - skb->data)))
281                                         goto out;
282
283                                 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
284
285                                 switch (icmp6->icmp6_type) {
286                                 case ICMPV6_MGM_QUERY:
287                                 case ICMPV6_MGM_REPORT:
288                                 case ICMPV6_MGM_REDUCTION:
289                                 case ICMPV6_MLD2_REPORT:
290                                         deliver = 1;
291                                         break;
292                                 }
293                                 goto out;
294                         }
295                         /* unknown RA - process it normally */
296                 }
297
298                 if (deliver)
299                         skb2 = skb_clone(skb, GFP_ATOMIC);
300                 else {
301                         skb2 = skb;
302                         skb = NULL;
303                 }
304
305                 if (skb2) {
306                         skb2->dev = skb2->dst->dev;
307                         ip6_mr_input(skb2);
308                 }
309         }
310 out:
311 #endif
312         if (likely(deliver))
313                 ip6_input(skb);
314         else {
315                 /* discard */
316                 kfree_skb(skb);
317         }
318
319         return 0;
320 }