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
ip6_rcv_finish(struct sk_buff * skb)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
ipv6_rcv(struct sk_buff * skb,struct net_device * dev,struct packet_type * pt,struct net_device * orig_dev)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
ip6_input_finish(struct sk_buff * skb)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
ip6_input(struct sk_buff * skb)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
ip6_mc_input(struct sk_buff * skb)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 !(ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) &&
259 likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
260 /*
261 * Okay, we try to forward - split and duplicate
262 * packets.
263 */
264 struct sk_buff *skb2;
265 struct inet6_skb_parm *opt = IP6CB(skb);
266
267 /* Check for MLD */
268 if (unlikely(opt->ra)) {
269 /* Check if this is a mld message */
270 u8 *ptr = skb_network_header(skb) + opt->ra;
271 struct icmp6hdr *icmp6;
272 u8 nexthdr = hdr->nexthdr;
273 int offset;
274
275 /* Check if the value of Router Alert
276 * is for MLD (0x0000).
277 */
278 if ((ptr[2] | ptr[3]) == 0) {
279 deliver = 0;
280
281 if (!ipv6_ext_hdr(nexthdr)) {
282 /* BUG */
283 goto out;
284 }
285 offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
286 &nexthdr);
287 if (offset < 0)
288 goto out;
289
290 if (nexthdr != IPPROTO_ICMPV6)
291 goto out;
292
293 if (!pskb_may_pull(skb, (skb_network_header(skb) +
294 offset + 1 - skb->data)))
295 goto out;
296
297 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
298
299 switch (icmp6->icmp6_type) {
300 case ICMPV6_MGM_QUERY:
301 case ICMPV6_MGM_REPORT:
302 case ICMPV6_MGM_REDUCTION:
303 case ICMPV6_MLD2_REPORT:
304 deliver = 1;
305 break;
306 }
307 goto out;
308 }
309 /* unknown RA - process it normally */
310 }
311
312 if (deliver)
313 skb2 = skb_clone(skb, GFP_ATOMIC);
314 else {
315 skb2 = skb;
316 skb = NULL;
317 }
318
319 if (skb2) {
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 }
334