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 void udp_v6_early_demux(struct sk_buff *);
51 void tcp_v6_early_demux(struct sk_buff *);
52 int ip6_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
54 /* if ingress device is enslaved to an L3 master device pass the
55 * skb to its handler for processing
57 skb = l3mdev_ip6_rcv(skb);
59 return NET_RX_SUCCESS;
61 if (READ_ONCE(net->ipv4.sysctl_ip_early_demux) &&
62 !skb_dst(skb) && !skb->sk) {
63 switch (ipv6_hdr(skb)->nexthdr) {
65 if (READ_ONCE(net->ipv4.sysctl_tcp_early_demux))
66 tcp_v6_early_demux(skb);
69 if (READ_ONCE(net->ipv4.sysctl_udp_early_demux))
70 udp_v6_early_demux(skb);
75 if (!skb_valid_dst(skb))
78 return dst_input(skb);
81 int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
83 const struct ipv6hdr *hdr;
85 struct inet6_dev *idev;
86 struct net *net = dev_net(skb->dev);
88 if (skb->pkt_type == PACKET_OTHERHOST) {
95 idev = __in6_dev_get(skb->dev);
97 __IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_IN, skb->len);
99 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
100 !idev || unlikely(idev->cnf.disable_ipv6)) {
101 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
105 memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
108 * Store incoming device index. When the packet will
109 * be queued, we cannot refer to skb->dev anymore.
111 * BTW, when we send a packet for our own local address on a
112 * non-loopback interface (e.g. ethX), it is being delivered
113 * via the loopback interface (lo) here; skb->dev = loopback_dev.
114 * It, however, should be considered as if it is being
115 * arrived via the sending interface (ethX), because of the
116 * nature of scoping architecture. --yoshfuji
118 IP6CB(skb)->iif = skb_valid_dst(skb) ? ip6_dst_idev(skb_dst(skb))->dev->ifindex : dev->ifindex;
120 if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
125 if (hdr->version != 6)
128 __IP6_ADD_STATS(net, idev,
129 IPSTATS_MIB_NOECTPKTS +
130 (ipv6_get_dsfield(hdr) & INET_ECN_MASK),
131 max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs));
134 * The loopback address must not be used as the source address in IPv6
135 * packets that are sent outside of a single node. [..]
136 * A packet received on an interface with a destination address
137 * of loopback must be dropped.
139 if ((ipv6_addr_loopback(&hdr->saddr) ||
140 ipv6_addr_loopback(&hdr->daddr)) &&
141 !(dev->flags & IFF_LOOPBACK))
144 /* RFC4291 Errata ID: 3480
145 * Interface-Local scope spans only a single interface on a
146 * node and is useful only for loopback transmission of
147 * multicast. Packets with interface-local scope received
148 * from another node must be discarded.
150 if (!(skb->pkt_type == PACKET_LOOPBACK ||
151 dev->flags & IFF_LOOPBACK) &&
152 ipv6_addr_is_multicast(&hdr->daddr) &&
153 IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 1)
156 /* If enabled, drop unicast packets that were encapsulated in link-layer
157 * multicast or broadcast to protected against the so-called "hole-196"
158 * attack in 802.11 wireless.
160 if (!ipv6_addr_is_multicast(&hdr->daddr) &&
161 (skb->pkt_type == PACKET_BROADCAST ||
162 skb->pkt_type == PACKET_MULTICAST) &&
163 idev->cnf.drop_unicast_in_l2_multicast)
167 * Nodes must not originate a packet to a multicast address whose scope
168 * field contains the reserved value 0; if such a packet is received, it
169 * must be silently dropped.
171 if (ipv6_addr_is_multicast(&hdr->daddr) &&
172 IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 0)
177 * Multicast addresses must not be used as source addresses in IPv6
178 * packets or appear in any Routing header.
180 if (ipv6_addr_is_multicast(&hdr->saddr))
183 skb->transport_header = skb->network_header + sizeof(*hdr);
184 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
186 pkt_len = ntohs(hdr->payload_len);
188 /* pkt_len may be zero if Jumbo payload option is present */
189 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
190 if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
192 idev, IPSTATS_MIB_INTRUNCATEDPKTS);
195 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
196 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
202 if (hdr->nexthdr == NEXTHDR_HOP) {
203 if (ipv6_parse_hopopts(skb) < 0) {
204 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
212 /* Must drop socket now because of tproxy. */
215 return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
216 net, NULL, skb, dev, NULL,
219 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
227 * Deliver the packet to the host
231 static int ip6_input_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
233 const struct inet6_protocol *ipprot;
234 struct inet6_dev *idev;
238 bool have_final = false;
241 * Parse extension headers
246 idev = ip6_dst_idev(skb_dst(skb));
247 if (!pskb_pull(skb, skb_transport_offset(skb)))
249 nhoff = IP6CB(skb)->nhoff;
250 nexthdr = skb_network_header(skb)[nhoff];
253 raw = raw6_local_deliver(skb, nexthdr);
254 ipprot = rcu_dereference(inet6_protos[nexthdr]);
259 if (!(ipprot->flags & INET6_PROTO_FINAL)) {
260 /* Once we've seen a final protocol don't
261 * allow encapsulation on any non-final
262 * ones. This allows foo in UDP encapsulation
267 } else if (ipprot->flags & INET6_PROTO_FINAL) {
268 const struct ipv6hdr *hdr;
270 /* Only do this once for first final protocol */
273 /* Free reference early: we don't need it any more,
274 and it may hold ip_conntrack module loaded
278 skb_postpull_rcsum(skb, skb_network_header(skb),
279 skb_network_header_len(skb));
281 if (ipv6_addr_is_multicast(&hdr->daddr) &&
282 !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
284 !ipv6_is_mld(skb, nexthdr, skb_network_header_len(skb)))
287 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
288 !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
291 ret = ipprot->handler(skb);
293 if (ipprot->flags & INET6_PROTO_FINAL) {
294 /* Not an extension header, most likely UDP
295 * encapsulation. Use return value as nexthdr
296 * protocol not nhoff (which presumably is
297 * not set by handler).
304 } else if (ret == 0) {
305 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
309 if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
310 __IP6_INC_STATS(net, idev,
311 IPSTATS_MIB_INUNKNOWNPROTOS);
312 icmpv6_send(skb, ICMPV6_PARAMPROB,
313 ICMPV6_UNK_NEXTHDR, nhoff);
317 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
325 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
332 int ip6_input(struct sk_buff *skb)
334 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN,
335 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
338 EXPORT_SYMBOL_GPL(ip6_input);
340 int ip6_mc_input(struct sk_buff *skb)
342 const struct ipv6hdr *hdr;
345 __IP6_UPD_PO_STATS(dev_net(skb_dst(skb)->dev),
346 ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INMCAST,
350 deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
352 #ifdef CONFIG_IPV6_MROUTE
354 * IPv6 multicast router mode is now supported ;)
356 if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding &&
357 !(ipv6_addr_type(&hdr->daddr) &
358 (IPV6_ADDR_LOOPBACK|IPV6_ADDR_LINKLOCAL)) &&
359 likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
361 * Okay, we try to forward - split and duplicate
364 struct sk_buff *skb2;
365 struct inet6_skb_parm *opt = IP6CB(skb);
368 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
369 /* Check if this is a mld message */
370 u8 nexthdr = hdr->nexthdr;
374 /* Check if the value of Router Alert
375 * is for MLD (0x0000).
377 if (opt->ra == htons(IPV6_OPT_ROUTERALERT_MLD)) {
380 if (!ipv6_ext_hdr(nexthdr)) {
384 offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
385 &nexthdr, &frag_off);
389 if (ipv6_is_mld(skb, nexthdr, offset))
394 /* unknown RA - process it normally */
398 skb2 = skb_clone(skb, GFP_ATOMIC);