xref: /openbmc/linux/net/ipv6/ip6_input.c (revision 64c70b1c)
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 
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 == 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 	struct ipv6hdr *hdr;
61 	u32 		pkt_len;
62 	struct inet6_dev *idev;
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(idev, IPSTATS_MIB_INRECEIVES);
74 
75 	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
76 		IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS);
77 		rcu_read_unlock();
78 		goto out;
79 	}
80 
81 	memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
82 
83 	/*
84 	 * Store incoming device index. When the packet will
85 	 * be queued, we cannot refer to skb->dev anymore.
86 	 *
87 	 * BTW, when we send a packet for our own local address on a
88 	 * non-loopback interface (e.g. ethX), it is being delivered
89 	 * via the loopback interface (lo) here; skb->dev = &loopback_dev.
90 	 * It, however, should be considered as if it is being
91 	 * arrived via the sending interface (ethX), because of the
92 	 * nature of scoping architecture. --yoshfuji
93 	 */
94 	IP6CB(skb)->iif = skb->dst ? ip6_dst_idev(skb->dst)->dev->ifindex : dev->ifindex;
95 
96 	if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
97 		goto err;
98 
99 	hdr = ipv6_hdr(skb);
100 
101 	if (hdr->version != 6)
102 		goto err;
103 
104 	skb->transport_header = skb->network_header + sizeof(*hdr);
105 	IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
106 
107 	pkt_len = ntohs(hdr->payload_len);
108 
109 	/* pkt_len may be zero if Jumbo payload option is present */
110 	if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
111 		if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
112 			IP6_INC_STATS_BH(idev, IPSTATS_MIB_INTRUNCATEDPKTS);
113 			goto drop;
114 		}
115 		if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
116 			IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
117 			goto drop;
118 		}
119 		hdr = ipv6_hdr(skb);
120 	}
121 
122 	if (hdr->nexthdr == NEXTHDR_HOP) {
123 		if (ipv6_parse_hopopts(&skb) < 0) {
124 			IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
125 			rcu_read_unlock();
126 			return 0;
127 		}
128 	}
129 
130 	rcu_read_unlock();
131 
132 	return NF_HOOK(PF_INET6,NF_IP6_PRE_ROUTING, skb, dev, NULL, ip6_rcv_finish);
133 err:
134 	IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
135 drop:
136 	rcu_read_unlock();
137 	kfree_skb(skb);
138 out:
139 	return 0;
140 }
141 
142 /*
143  *	Deliver the packet to the host
144  */
145 
146 
147 static inline int ip6_input_finish(struct sk_buff *skb)
148 {
149 	struct inet6_protocol *ipprot;
150 	struct sock *raw_sk;
151 	unsigned int nhoff;
152 	int nexthdr;
153 	u8 hash;
154 	struct inet6_dev *idev;
155 
156 	/*
157 	 *	Parse extension headers
158 	 */
159 
160 	rcu_read_lock();
161 resubmit:
162 	idev = ip6_dst_idev(skb->dst);
163 	if (!pskb_pull(skb, skb_transport_offset(skb)))
164 		goto discard;
165 	nhoff = IP6CB(skb)->nhoff;
166 	nexthdr = skb_network_header(skb)[nhoff];
167 
168 	raw_sk = sk_head(&raw_v6_htable[nexthdr & (MAX_INET_PROTOS - 1)]);
169 	if (raw_sk && !ipv6_raw_deliver(skb, nexthdr))
170 		raw_sk = NULL;
171 
172 	hash = nexthdr & (MAX_INET_PROTOS - 1);
173 	if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) {
174 		int ret;
175 
176 		if (ipprot->flags & INET6_PROTO_FINAL) {
177 			struct ipv6hdr *hdr;
178 
179 			/* Free reference early: we don't need it any more,
180 			   and it may hold ip_conntrack module loaded
181 			   indefinitely. */
182 			nf_reset(skb);
183 
184 			skb_postpull_rcsum(skb, skb_network_header(skb),
185 					   skb_network_header_len(skb));
186 			hdr = ipv6_hdr(skb);
187 			if (ipv6_addr_is_multicast(&hdr->daddr) &&
188 			    !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
189 			    &hdr->saddr) &&
190 			    !ipv6_is_mld(skb, nexthdr))
191 				goto discard;
192 		}
193 		if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
194 		    !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
195 			goto discard;
196 
197 		ret = ipprot->handler(&skb);
198 		if (ret > 0)
199 			goto resubmit;
200 		else if (ret == 0)
201 			IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS);
202 	} else {
203 		if (!raw_sk) {
204 			if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
205 				IP6_INC_STATS_BH(idev, IPSTATS_MIB_INUNKNOWNPROTOS);
206 				icmpv6_send(skb, ICMPV6_PARAMPROB,
207 					    ICMPV6_UNK_NEXTHDR, nhoff,
208 					    skb->dev);
209 			}
210 		} else
211 			IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS);
212 		kfree_skb(skb);
213 	}
214 	rcu_read_unlock();
215 	return 0;
216 
217 discard:
218 	IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS);
219 	rcu_read_unlock();
220 	kfree_skb(skb);
221 	return 0;
222 }
223 
224 
225 int ip6_input(struct sk_buff *skb)
226 {
227 	return NF_HOOK(PF_INET6,NF_IP6_LOCAL_IN, skb, skb->dev, NULL, 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 = unlikely(skb->dev->flags & (IFF_PROMISC|IFF_ALLMULTI)) ||
239 	    ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
240 
241 	/*
242 	 *	IPv6 multicast router mode isnt currently supported.
243 	 */
244 #if 0
245 	if (ipv6_config.multicast_route) {
246 		int addr_type;
247 
248 		addr_type = ipv6_addr_type(&hdr->daddr);
249 
250 		if (!(addr_type & (IPV6_ADDR_LOOPBACK | IPV6_ADDR_LINKLOCAL))) {
251 			struct sk_buff *skb2;
252 			struct dst_entry *dst;
253 
254 			dst = skb->dst;
255 
256 			if (deliver) {
257 				skb2 = skb_clone(skb, GFP_ATOMIC);
258 				dst_output(skb2);
259 			} else {
260 				dst_output(skb);
261 				return 0;
262 			}
263 		}
264 	}
265 #endif
266 
267 	if (likely(deliver)) {
268 		ip6_input(skb);
269 		return 0;
270 	}
271 	/* discard */
272 	kfree_skb(skb);
273 
274 	return 0;
275 }
276