3 * Linux INET6 implementation
6 * Pedro Roque <roque@di.fc.ul.pt>
7 * Ian P. Morris <I.P.Morris@soton.ac.uk>
9 * Based in linux/net/ipv4/ip_input.c
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.
18 * Mitsuru KANDA @USAGI and
19 * YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs().
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>
33 #include <linux/netfilter.h>
34 #include <linux/netfilter_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>
47 #include <net/inet_ecn.h>
48 #include <net/dst_metadata.h>
50 int ip6_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
52 /* if ingress device is enslaved to an L3 master device pass the
53 * skb to its handler for processing
55 skb = l3mdev_ip6_rcv(skb);
57 return NET_RX_SUCCESS;
59 if (net->ipv4.sysctl_ip_early_demux && !skb_dst(skb) && skb->sk == NULL) {
60 const struct inet6_protocol *ipprot;
62 ipprot = rcu_dereference(inet6_protos[ipv6_hdr(skb)->nexthdr]);
63 if (ipprot && ipprot->early_demux)
64 ipprot->early_demux(skb);
66 if (!skb_valid_dst(skb))
69 return dst_input(skb);
72 int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
74 const struct ipv6hdr *hdr;
76 struct inet6_dev *idev;
77 struct net *net = dev_net(skb->dev);
79 if (skb->pkt_type == PACKET_OTHERHOST) {
86 idev = __in6_dev_get(skb->dev);
88 __IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_IN, skb->len);
90 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
91 !idev || unlikely(idev->cnf.disable_ipv6)) {
92 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
96 memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
99 * Store incoming device index. When the packet will
100 * be queued, we cannot refer to skb->dev anymore.
102 * BTW, when we send a packet for our own local address on a
103 * non-loopback interface (e.g. ethX), it is being delivered
104 * via the loopback interface (lo) here; skb->dev = loopback_dev.
105 * It, however, should be considered as if it is being
106 * arrived via the sending interface (ethX), because of the
107 * nature of scoping architecture. --yoshfuji
109 IP6CB(skb)->iif = skb_valid_dst(skb) ? ip6_dst_idev(skb_dst(skb))->dev->ifindex : dev->ifindex;
111 if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
116 if (hdr->version != 6)
119 __IP6_ADD_STATS(net, idev,
120 IPSTATS_MIB_NOECTPKTS +
121 (ipv6_get_dsfield(hdr) & INET_ECN_MASK),
122 max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs));
125 * The loopback address must not be used as the source address in IPv6
126 * packets that are sent outside of a single node. [..]
127 * A packet received on an interface with a destination address
128 * of loopback must be dropped.
130 if ((ipv6_addr_loopback(&hdr->saddr) ||
131 ipv6_addr_loopback(&hdr->daddr)) &&
132 !(dev->flags & IFF_LOOPBACK))
135 /* RFC4291 Errata ID: 3480
136 * Interface-Local scope spans only a single interface on a
137 * node and is useful only for loopback transmission of
138 * multicast. Packets with interface-local scope received
139 * from another node must be discarded.
141 if (!(skb->pkt_type == PACKET_LOOPBACK ||
142 dev->flags & IFF_LOOPBACK) &&
143 ipv6_addr_is_multicast(&hdr->daddr) &&
144 IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 1)
147 /* If enabled, drop unicast packets that were encapsulated in link-layer
148 * multicast or broadcast to protected against the so-called "hole-196"
149 * attack in 802.11 wireless.
151 if (!ipv6_addr_is_multicast(&hdr->daddr) &&
152 (skb->pkt_type == PACKET_BROADCAST ||
153 skb->pkt_type == PACKET_MULTICAST) &&
154 idev->cnf.drop_unicast_in_l2_multicast)
158 * Nodes must not originate a packet to a multicast address whose scope
159 * field contains the reserved value 0; if such a packet is received, it
160 * must be silently dropped.
162 if (ipv6_addr_is_multicast(&hdr->daddr) &&
163 IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 0)
168 * Multicast addresses must not be used as source addresses in IPv6
169 * packets or appear in any Routing header.
171 if (ipv6_addr_is_multicast(&hdr->saddr))
174 skb->transport_header = skb->network_header + sizeof(*hdr);
175 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
177 pkt_len = ntohs(hdr->payload_len);
179 /* pkt_len may be zero if Jumbo payload option is present */
180 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
181 if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
183 idev, IPSTATS_MIB_INTRUNCATEDPKTS);
186 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
187 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
193 if (hdr->nexthdr == NEXTHDR_HOP) {
194 if (ipv6_parse_hopopts(skb) < 0) {
195 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
203 /* Must drop socket now because of tproxy. */
206 return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
207 net, NULL, skb, dev, NULL,
210 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
218 * Deliver the packet to the host
222 static int ip6_input_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
224 const struct inet6_protocol *ipprot;
225 struct inet6_dev *idev;
229 bool have_final = false;
232 * Parse extension headers
237 idev = ip6_dst_idev(skb_dst(skb));
238 if (!pskb_pull(skb, skb_transport_offset(skb)))
240 nhoff = IP6CB(skb)->nhoff;
241 nexthdr = skb_network_header(skb)[nhoff];
244 raw = raw6_local_deliver(skb, nexthdr);
245 ipprot = rcu_dereference(inet6_protos[nexthdr]);
250 if (!(ipprot->flags & INET6_PROTO_FINAL)) {
251 /* Once we've seen a final protocol don't
252 * allow encapsulation on any non-final
253 * ones. This allows foo in UDP encapsulation
258 } else if (ipprot->flags & INET6_PROTO_FINAL) {
259 const struct ipv6hdr *hdr;
261 /* Only do this once for first final protocol */
264 /* Free reference early: we don't need it any more,
265 and it may hold ip_conntrack module loaded
269 skb_postpull_rcsum(skb, skb_network_header(skb),
270 skb_network_header_len(skb));
272 if (ipv6_addr_is_multicast(&hdr->daddr) &&
273 !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
275 !ipv6_is_mld(skb, nexthdr, skb_network_header_len(skb)))
278 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
279 !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
282 ret = ipprot->handler(skb);
284 if (ipprot->flags & INET6_PROTO_FINAL) {
285 /* Not an extension header, most likely UDP
286 * encapsulation. Use return value as nexthdr
287 * protocol not nhoff (which presumably is
288 * not set by handler).
295 } else if (ret == 0) {
296 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
300 if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
301 __IP6_INC_STATS(net, idev,
302 IPSTATS_MIB_INUNKNOWNPROTOS);
303 icmpv6_send(skb, ICMPV6_PARAMPROB,
304 ICMPV6_UNK_NEXTHDR, nhoff);
308 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
316 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
323 int ip6_input(struct sk_buff *skb)
325 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN,
326 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
329 EXPORT_SYMBOL_GPL(ip6_input);
331 int ip6_mc_input(struct sk_buff *skb)
333 const struct ipv6hdr *hdr;
336 __IP6_UPD_PO_STATS(dev_net(skb_dst(skb)->dev),
337 ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INMCAST,
341 deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
343 #ifdef CONFIG_IPV6_MROUTE
345 * IPv6 multicast router mode is now supported ;)
347 if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding &&
348 !(ipv6_addr_type(&hdr->daddr) &
349 (IPV6_ADDR_LOOPBACK|IPV6_ADDR_LINKLOCAL)) &&
350 likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
352 * Okay, we try to forward - split and duplicate
355 struct sk_buff *skb2;
356 struct inet6_skb_parm *opt = IP6CB(skb);
359 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
360 /* Check if this is a mld message */
361 u8 nexthdr = hdr->nexthdr;
365 /* Check if the value of Router Alert
366 * is for MLD (0x0000).
368 if (opt->ra == htons(IPV6_OPT_ROUTERALERT_MLD)) {
371 if (!ipv6_ext_hdr(nexthdr)) {
375 offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
376 &nexthdr, &frag_off);
380 if (ipv6_is_mld(skb, nexthdr, offset))
385 /* unknown RA - process it normally */
389 skb2 = skb_clone(skb, GFP_ATOMIC);