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 static void ip6_rcv_finish_core(struct net *net, struct sock *sk,
53 void (*edemux)(struct sk_buff *skb);
55 if (net->ipv4.sysctl_ip_early_demux && !skb_dst(skb) && skb->sk == NULL) {
56 const struct inet6_protocol *ipprot;
58 ipprot = rcu_dereference(inet6_protos[ipv6_hdr(skb)->nexthdr]);
59 if (ipprot && (edemux = READ_ONCE(ipprot->early_demux)))
62 if (!skb_valid_dst(skb))
66 int ip6_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
68 /* if ingress device is enslaved to an L3 master device pass the
69 * skb to its handler for processing
71 skb = l3mdev_ip6_rcv(skb);
73 return NET_RX_SUCCESS;
74 ip6_rcv_finish_core(net, sk, skb);
76 return dst_input(skb);
79 static void ip6_sublist_rcv_finish(struct list_head *head)
81 struct sk_buff *skb, *next;
83 list_for_each_entry_safe(skb, next, head, list) {
84 skb_list_del_init(skb);
89 static void ip6_list_rcv_finish(struct net *net, struct sock *sk,
90 struct list_head *head)
92 struct dst_entry *curr_dst = NULL;
93 struct sk_buff *skb, *next;
94 struct list_head sublist;
96 INIT_LIST_HEAD(&sublist);
97 list_for_each_entry_safe(skb, next, head, list) {
98 struct dst_entry *dst;
100 skb_list_del_init(skb);
101 /* if ingress device is enslaved to an L3 master device pass the
102 * skb to its handler for processing
104 skb = l3mdev_ip6_rcv(skb);
107 ip6_rcv_finish_core(net, sk, skb);
109 if (curr_dst != dst) {
110 /* dispatch old sublist */
111 if (!list_empty(&sublist))
112 ip6_sublist_rcv_finish(&sublist);
113 /* start new sublist */
114 INIT_LIST_HEAD(&sublist);
117 list_add_tail(&skb->list, &sublist);
119 /* dispatch final sublist */
120 ip6_sublist_rcv_finish(&sublist);
123 static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
126 const struct ipv6hdr *hdr;
128 struct inet6_dev *idev;
130 if (skb->pkt_type == PACKET_OTHERHOST) {
137 idev = __in6_dev_get(skb->dev);
139 __IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_IN, skb->len);
141 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
142 !idev || unlikely(idev->cnf.disable_ipv6)) {
143 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
147 memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
150 * Store incoming device index. When the packet will
151 * be queued, we cannot refer to skb->dev anymore.
153 * BTW, when we send a packet for our own local address on a
154 * non-loopback interface (e.g. ethX), it is being delivered
155 * via the loopback interface (lo) here; skb->dev = loopback_dev.
156 * It, however, should be considered as if it is being
157 * arrived via the sending interface (ethX), because of the
158 * nature of scoping architecture. --yoshfuji
160 IP6CB(skb)->iif = skb_valid_dst(skb) ? ip6_dst_idev(skb_dst(skb))->dev->ifindex : dev->ifindex;
162 if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
167 if (hdr->version != 6)
170 __IP6_ADD_STATS(net, idev,
171 IPSTATS_MIB_NOECTPKTS +
172 (ipv6_get_dsfield(hdr) & INET_ECN_MASK),
173 max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs));
176 * The loopback address must not be used as the source address in IPv6
177 * packets that are sent outside of a single node. [..]
178 * A packet received on an interface with a destination address
179 * of loopback must be dropped.
181 if ((ipv6_addr_loopback(&hdr->saddr) ||
182 ipv6_addr_loopback(&hdr->daddr)) &&
183 !(dev->flags & IFF_LOOPBACK))
186 /* RFC4291 Errata ID: 3480
187 * Interface-Local scope spans only a single interface on a
188 * node and is useful only for loopback transmission of
189 * multicast. Packets with interface-local scope received
190 * from another node must be discarded.
192 if (!(skb->pkt_type == PACKET_LOOPBACK ||
193 dev->flags & IFF_LOOPBACK) &&
194 ipv6_addr_is_multicast(&hdr->daddr) &&
195 IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 1)
198 /* If enabled, drop unicast packets that were encapsulated in link-layer
199 * multicast or broadcast to protected against the so-called "hole-196"
200 * attack in 802.11 wireless.
202 if (!ipv6_addr_is_multicast(&hdr->daddr) &&
203 (skb->pkt_type == PACKET_BROADCAST ||
204 skb->pkt_type == PACKET_MULTICAST) &&
205 idev->cnf.drop_unicast_in_l2_multicast)
209 * Nodes must not originate a packet to a multicast address whose scope
210 * field contains the reserved value 0; if such a packet is received, it
211 * must be silently dropped.
213 if (ipv6_addr_is_multicast(&hdr->daddr) &&
214 IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 0)
219 * Multicast addresses must not be used as source addresses in IPv6
220 * packets or appear in any Routing header.
222 if (ipv6_addr_is_multicast(&hdr->saddr))
225 skb->transport_header = skb->network_header + sizeof(*hdr);
226 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
228 pkt_len = ntohs(hdr->payload_len);
230 /* pkt_len may be zero if Jumbo payload option is present */
231 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
232 if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
234 idev, IPSTATS_MIB_INTRUNCATEDPKTS);
237 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
238 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
244 if (hdr->nexthdr == NEXTHDR_HOP) {
245 if (ipv6_parse_hopopts(skb) < 0) {
246 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
254 /* Must drop socket now because of tproxy. */
259 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
266 int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
268 struct net *net = dev_net(skb->dev);
270 skb = ip6_rcv_core(skb, dev, net);
273 return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
274 net, NULL, skb, dev, NULL,
278 static void ip6_sublist_rcv(struct list_head *head, struct net_device *dev,
281 NF_HOOK_LIST(NFPROTO_IPV6, NF_INET_PRE_ROUTING, net, NULL,
282 head, dev, NULL, ip6_rcv_finish);
283 ip6_list_rcv_finish(net, NULL, head);
286 /* Receive a list of IPv6 packets */
287 void ipv6_list_rcv(struct list_head *head, struct packet_type *pt,
288 struct net_device *orig_dev)
290 struct net_device *curr_dev = NULL;
291 struct net *curr_net = NULL;
292 struct sk_buff *skb, *next;
293 struct list_head sublist;
295 INIT_LIST_HEAD(&sublist);
296 list_for_each_entry_safe(skb, next, head, list) {
297 struct net_device *dev = skb->dev;
298 struct net *net = dev_net(dev);
300 skb_list_del_init(skb);
301 skb = ip6_rcv_core(skb, dev, net);
305 if (curr_dev != dev || curr_net != net) {
306 /* dispatch old sublist */
307 if (!list_empty(&sublist))
308 ip6_sublist_rcv(&sublist, curr_dev, curr_net);
309 /* start new sublist */
310 INIT_LIST_HEAD(&sublist);
314 list_add_tail(&skb->list, &sublist);
316 /* dispatch final sublist */
317 ip6_sublist_rcv(&sublist, curr_dev, curr_net);
321 * Deliver the packet to the host
325 static int ip6_input_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
327 const struct inet6_protocol *ipprot;
328 struct inet6_dev *idev;
332 bool have_final = false;
335 * Parse extension headers
340 idev = ip6_dst_idev(skb_dst(skb));
341 if (!pskb_pull(skb, skb_transport_offset(skb)))
343 nhoff = IP6CB(skb)->nhoff;
344 nexthdr = skb_network_header(skb)[nhoff];
347 raw = raw6_local_deliver(skb, nexthdr);
348 ipprot = rcu_dereference(inet6_protos[nexthdr]);
353 if (!(ipprot->flags & INET6_PROTO_FINAL)) {
354 /* Once we've seen a final protocol don't
355 * allow encapsulation on any non-final
356 * ones. This allows foo in UDP encapsulation
361 } else if (ipprot->flags & INET6_PROTO_FINAL) {
362 const struct ipv6hdr *hdr;
364 /* Only do this once for first final protocol */
367 /* Free reference early: we don't need it any more,
368 and it may hold ip_conntrack module loaded
372 skb_postpull_rcsum(skb, skb_network_header(skb),
373 skb_network_header_len(skb));
375 if (ipv6_addr_is_multicast(&hdr->daddr) &&
376 !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
378 !ipv6_is_mld(skb, nexthdr, skb_network_header_len(skb)))
381 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
382 !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
385 ret = ipprot->handler(skb);
387 if (ipprot->flags & INET6_PROTO_FINAL) {
388 /* Not an extension header, most likely UDP
389 * encapsulation. Use return value as nexthdr
390 * protocol not nhoff (which presumably is
391 * not set by handler).
398 } else if (ret == 0) {
399 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
403 if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
404 __IP6_INC_STATS(net, idev,
405 IPSTATS_MIB_INUNKNOWNPROTOS);
406 icmpv6_send(skb, ICMPV6_PARAMPROB,
407 ICMPV6_UNK_NEXTHDR, nhoff);
411 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
419 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
426 int ip6_input(struct sk_buff *skb)
428 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN,
429 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
432 EXPORT_SYMBOL_GPL(ip6_input);
434 int ip6_mc_input(struct sk_buff *skb)
436 const struct ipv6hdr *hdr;
439 __IP6_UPD_PO_STATS(dev_net(skb_dst(skb)->dev),
440 __in6_dev_get_safely(skb->dev), IPSTATS_MIB_INMCAST,
444 deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
446 #ifdef CONFIG_IPV6_MROUTE
448 * IPv6 multicast router mode is now supported ;)
450 if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding &&
451 !(ipv6_addr_type(&hdr->daddr) &
452 (IPV6_ADDR_LOOPBACK|IPV6_ADDR_LINKLOCAL)) &&
453 likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
455 * Okay, we try to forward - split and duplicate
458 struct sk_buff *skb2;
459 struct inet6_skb_parm *opt = IP6CB(skb);
462 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
463 /* Check if this is a mld message */
464 u8 nexthdr = hdr->nexthdr;
468 /* Check if the value of Router Alert
469 * is for MLD (0x0000).
471 if (opt->ra == htons(IPV6_OPT_ROUTERALERT_MLD)) {
474 if (!ipv6_ext_hdr(nexthdr)) {
478 offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
479 &nexthdr, &frag_off);
483 if (ipv6_is_mld(skb, nexthdr, offset))
488 /* unknown RA - process it normally */
492 skb2 = skb_clone(skb, GFP_ATOMIC);