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Commit | Line | Data |
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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 | ||
48 | ||
49 | ||
50 | inline int ip6_rcv_finish( struct sk_buff *skb) | |
51 | { | |
52 | if (skb_dst(skb) == NULL) | |
53 | ip6_route_input(skb); | |
54 | ||
55 | return dst_input(skb); | |
56 | } | |
57 | ||
58 | int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev) | |
59 | { | |
60 | const struct ipv6hdr *hdr; | |
61 | u32 pkt_len; | |
62 | struct inet6_dev *idev; | |
63 | struct net *net = dev_net(skb->dev); | |
64 | ||
65 | if (skb->pkt_type == PACKET_OTHERHOST) { | |
66 | kfree_skb(skb); | |
67 | return NET_RX_DROP; | |
68 | } | |
69 | ||
70 | rcu_read_lock(); | |
71 | ||
72 | idev = __in6_dev_get(skb->dev); | |
73 | ||
74 | IP6_UPD_PO_STATS_BH(net, idev, IPSTATS_MIB_IN, skb->len); | |
75 | ||
76 | if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL || | |
77 | !idev || unlikely(idev->cnf.disable_ipv6)) { | |
78 | IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS); | |
79 | goto drop; | |
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(skb) ? ip6_dst_idev(skb_dst(skb))->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 | /* | |
115 | * RFC4291 2.7 | |
116 | * Multicast addresses must not be used as source addresses in IPv6 | |
117 | * packets or appear in any Routing header. | |
118 | */ | |
119 | if (ipv6_addr_is_multicast(&hdr->saddr)) | |
120 | goto err; | |
121 | ||
122 | skb->transport_header = skb->network_header + sizeof(*hdr); | |
123 | IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr); | |
124 | ||
125 | pkt_len = ntohs(hdr->payload_len); | |
126 | ||
127 | /* pkt_len may be zero if Jumbo payload option is present */ | |
128 | if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) { | |
129 | if (pkt_len + sizeof(struct ipv6hdr) > skb->len) { | |
130 | IP6_INC_STATS_BH(net, | |
131 | idev, IPSTATS_MIB_INTRUNCATEDPKTS); | |
132 | goto drop; | |
133 | } | |
134 | if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) { | |
135 | IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS); | |
136 | goto drop; | |
137 | } | |
138 | hdr = ipv6_hdr(skb); | |
139 | } | |
140 | ||
141 | if (hdr->nexthdr == NEXTHDR_HOP) { | |
142 | if (ipv6_parse_hopopts(skb) < 0) { | |
143 | IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS); | |
144 | rcu_read_unlock(); | |
145 | return NET_RX_DROP; | |
146 | } | |
147 | } | |
148 | ||
149 | rcu_read_unlock(); | |
150 | ||
151 | /* Must drop socket now because of tproxy. */ | |
152 | skb_orphan(skb); | |
153 | ||
154 | return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, skb, dev, NULL, | |
155 | ip6_rcv_finish); | |
156 | err: | |
157 | IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS); | |
158 | drop: | |
159 | rcu_read_unlock(); | |
160 | kfree_skb(skb); | |
161 | return NET_RX_DROP; | |
162 | } | |
163 | ||
164 | /* | |
165 | * Deliver the packet to the host | |
166 | */ | |
167 | ||
168 | ||
169 | static int ip6_input_finish(struct sk_buff *skb) | |
170 | { | |
171 | const struct inet6_protocol *ipprot; | |
172 | unsigned int nhoff; | |
173 | int nexthdr, raw; | |
174 | u8 hash; | |
175 | struct inet6_dev *idev; | |
176 | struct net *net = dev_net(skb_dst(skb)->dev); | |
177 | ||
178 | /* | |
179 | * Parse extension headers | |
180 | */ | |
181 | ||
182 | rcu_read_lock(); | |
183 | resubmit: | |
184 | idev = ip6_dst_idev(skb_dst(skb)); | |
185 | if (!pskb_pull(skb, skb_transport_offset(skb))) | |
186 | goto discard; | |
187 | nhoff = IP6CB(skb)->nhoff; | |
188 | nexthdr = skb_network_header(skb)[nhoff]; | |
189 | ||
190 | raw = raw6_local_deliver(skb, nexthdr); | |
191 | ||
192 | hash = nexthdr & (MAX_INET_PROTOS - 1); | |
193 | if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) { | |
194 | int ret; | |
195 | ||
196 | if (ipprot->flags & INET6_PROTO_FINAL) { | |
197 | const struct ipv6hdr *hdr; | |
198 | ||
199 | /* Free reference early: we don't need it any more, | |
200 | and it may hold ip_conntrack module loaded | |
201 | indefinitely. */ | |
202 | nf_reset(skb); | |
203 | ||
204 | skb_postpull_rcsum(skb, skb_network_header(skb), | |
205 | skb_network_header_len(skb)); | |
206 | hdr = ipv6_hdr(skb); | |
207 | if (ipv6_addr_is_multicast(&hdr->daddr) && | |
208 | !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, | |
209 | &hdr->saddr) && | |
210 | !ipv6_is_mld(skb, nexthdr)) | |
211 | goto discard; | |
212 | } | |
213 | if (!(ipprot->flags & INET6_PROTO_NOPOLICY) && | |
214 | !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) | |
215 | goto discard; | |
216 | ||
217 | ret = ipprot->handler(skb); | |
218 | if (ret > 0) | |
219 | goto resubmit; | |
220 | else if (ret == 0) | |
221 | IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS); | |
222 | } else { | |
223 | if (!raw) { | |
224 | if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { | |
225 | IP6_INC_STATS_BH(net, idev, | |
226 | IPSTATS_MIB_INUNKNOWNPROTOS); | |
227 | icmpv6_send(skb, ICMPV6_PARAMPROB, | |
228 | ICMPV6_UNK_NEXTHDR, nhoff); | |
229 | } | |
230 | } else | |
231 | IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS); | |
232 | kfree_skb(skb); | |
233 | } | |
234 | rcu_read_unlock(); | |
235 | return 0; | |
236 | ||
237 | discard: | |
238 | IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS); | |
239 | rcu_read_unlock(); | |
240 | kfree_skb(skb); | |
241 | return 0; | |
242 | } | |
243 | ||
244 | ||
245 | int ip6_input(struct sk_buff *skb) | |
246 | { | |
247 | return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN, skb, skb->dev, NULL, | |
248 | ip6_input_finish); | |
249 | } | |
250 | ||
251 | int ip6_mc_input(struct sk_buff *skb) | |
252 | { | |
253 | const struct ipv6hdr *hdr; | |
254 | int deliver; | |
255 | ||
256 | IP6_UPD_PO_STATS_BH(dev_net(skb_dst(skb)->dev), | |
257 | ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INMCAST, | |
258 | skb->len); | |
259 | ||
260 | hdr = ipv6_hdr(skb); | |
261 | deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL); | |
262 | ||
263 | #ifdef CONFIG_IPV6_MROUTE | |
264 | /* | |
265 | * IPv6 multicast router mode is now supported ;) | |
266 | */ | |
267 | if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding && | |
268 | !(ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) && | |
269 | likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) { | |
270 | /* | |
271 | * Okay, we try to forward - split and duplicate | |
272 | * packets. | |
273 | */ | |
274 | struct sk_buff *skb2; | |
275 | struct inet6_skb_parm *opt = IP6CB(skb); | |
276 | ||
277 | /* Check for MLD */ | |
278 | if (unlikely(opt->ra)) { | |
279 | /* Check if this is a mld message */ | |
280 | u8 *ptr = skb_network_header(skb) + opt->ra; | |
281 | struct icmp6hdr *icmp6; | |
282 | u8 nexthdr = hdr->nexthdr; | |
283 | __be16 frag_off; | |
284 | int offset; | |
285 | ||
286 | /* Check if the value of Router Alert | |
287 | * is for MLD (0x0000). | |
288 | */ | |
289 | if ((ptr[2] | ptr[3]) == 0) { | |
290 | deliver = 0; | |
291 | ||
292 | if (!ipv6_ext_hdr(nexthdr)) { | |
293 | /* BUG */ | |
294 | goto out; | |
295 | } | |
296 | offset = ipv6_skip_exthdr(skb, sizeof(*hdr), | |
297 | &nexthdr, &frag_off); | |
298 | if (offset < 0) | |
299 | goto out; | |
300 | ||
301 | if (nexthdr != IPPROTO_ICMPV6) | |
302 | goto out; | |
303 | ||
304 | if (!pskb_may_pull(skb, (skb_network_header(skb) + | |
305 | offset + 1 - skb->data))) | |
306 | goto out; | |
307 | ||
308 | icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset); | |
309 | ||
310 | switch (icmp6->icmp6_type) { | |
311 | case ICMPV6_MGM_QUERY: | |
312 | case ICMPV6_MGM_REPORT: | |
313 | case ICMPV6_MGM_REDUCTION: | |
314 | case ICMPV6_MLD2_REPORT: | |
315 | deliver = 1; | |
316 | break; | |
317 | } | |
318 | goto out; | |
319 | } | |
320 | /* unknown RA - process it normally */ | |
321 | } | |
322 | ||
323 | if (deliver) | |
324 | skb2 = skb_clone(skb, GFP_ATOMIC); | |
325 | else { | |
326 | skb2 = skb; | |
327 | skb = NULL; | |
328 | } | |
329 | ||
330 | if (skb2) { | |
331 | ip6_mr_input(skb2); | |
332 | } | |
333 | } | |
334 | out: | |
335 | #endif | |
336 | if (likely(deliver)) | |
337 | ip6_input(skb); | |
338 | else { | |
339 | /* discard */ | |
340 | kfree_skb(skb); | |
341 | } | |
342 | ||
343 | return 0; | |
344 | } |