1 // SPDX-License-Identifier: GPL-2.0-or-later
4 * Linux INET6 implementation
7 * Pedro Roque <roque@di.fc.ul.pt>
8 * Ian P. Morris <I.P.Morris@soton.ac.uk>
10 * Based in linux/net/ipv4/ip_input.c
14 * Mitsuru KANDA @USAGI and
15 * YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs().
18 #include <linux/errno.h>
19 #include <linux/types.h>
20 #include <linux/socket.h>
21 #include <linux/sockios.h>
22 #include <linux/net.h>
23 #include <linux/netdevice.h>
24 #include <linux/in6.h>
25 #include <linux/icmpv6.h>
26 #include <linux/mroute6.h>
27 #include <linux/slab.h>
28 #include <linux/indirect_call_wrapper.h>
30 #include <linux/netfilter.h>
31 #include <linux/netfilter_ipv6.h>
37 #include <net/protocol.h>
38 #include <net/transp_v6.h>
39 #include <net/rawv6.h>
40 #include <net/ndisc.h>
41 #include <net/ip6_route.h>
42 #include <net/addrconf.h>
44 #include <net/inet_ecn.h>
45 #include <net/dst_metadata.h>
47 INDIRECT_CALLABLE_DECLARE(void udp_v6_early_demux(struct sk_buff *));
48 INDIRECT_CALLABLE_DECLARE(void tcp_v6_early_demux(struct sk_buff *));
49 static void ip6_rcv_finish_core(struct net *net, struct sock *sk,
52 void (*edemux)(struct sk_buff *skb);
54 if (net->ipv4.sysctl_ip_early_demux && !skb_dst(skb) && skb->sk == NULL) {
55 const struct inet6_protocol *ipprot;
57 ipprot = rcu_dereference(inet6_protos[ipv6_hdr(skb)->nexthdr]);
58 if (ipprot && (edemux = READ_ONCE(ipprot->early_demux)))
59 INDIRECT_CALL_2(edemux, tcp_v6_early_demux,
60 udp_v6_early_demux, skb);
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) &&
184 !netif_is_l3_master(dev))
187 /* RFC4291 Errata ID: 3480
188 * Interface-Local scope spans only a single interface on a
189 * node and is useful only for loopback transmission of
190 * multicast. Packets with interface-local scope received
191 * from another node must be discarded.
193 if (!(skb->pkt_type == PACKET_LOOPBACK ||
194 dev->flags & IFF_LOOPBACK) &&
195 ipv6_addr_is_multicast(&hdr->daddr) &&
196 IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 1)
199 /* If enabled, drop unicast packets that were encapsulated in link-layer
200 * multicast or broadcast to protected against the so-called "hole-196"
201 * attack in 802.11 wireless.
203 if (!ipv6_addr_is_multicast(&hdr->daddr) &&
204 (skb->pkt_type == PACKET_BROADCAST ||
205 skb->pkt_type == PACKET_MULTICAST) &&
206 idev->cnf.drop_unicast_in_l2_multicast)
210 * Nodes must not originate a packet to a multicast address whose scope
211 * field contains the reserved value 0; if such a packet is received, it
212 * must be silently dropped.
214 if (ipv6_addr_is_multicast(&hdr->daddr) &&
215 IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 0)
220 * Multicast addresses must not be used as source addresses in IPv6
221 * packets or appear in any Routing header.
223 if (ipv6_addr_is_multicast(&hdr->saddr))
226 skb->transport_header = skb->network_header + sizeof(*hdr);
227 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
229 pkt_len = ntohs(hdr->payload_len);
231 /* pkt_len may be zero if Jumbo payload option is present */
232 if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
233 if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
235 idev, IPSTATS_MIB_INTRUNCATEDPKTS);
238 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
239 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
245 if (hdr->nexthdr == NEXTHDR_HOP) {
246 if (ipv6_parse_hopopts(skb) < 0) {
247 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
255 /* Must drop socket now because of tproxy. */
260 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
267 int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
269 struct net *net = dev_net(skb->dev);
271 skb = ip6_rcv_core(skb, dev, net);
274 return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
275 net, NULL, skb, dev, NULL,
279 static void ip6_sublist_rcv(struct list_head *head, struct net_device *dev,
282 NF_HOOK_LIST(NFPROTO_IPV6, NF_INET_PRE_ROUTING, net, NULL,
283 head, dev, NULL, ip6_rcv_finish);
284 ip6_list_rcv_finish(net, NULL, head);
287 /* Receive a list of IPv6 packets */
288 void ipv6_list_rcv(struct list_head *head, struct packet_type *pt,
289 struct net_device *orig_dev)
291 struct net_device *curr_dev = NULL;
292 struct net *curr_net = NULL;
293 struct sk_buff *skb, *next;
294 struct list_head sublist;
296 INIT_LIST_HEAD(&sublist);
297 list_for_each_entry_safe(skb, next, head, list) {
298 struct net_device *dev = skb->dev;
299 struct net *net = dev_net(dev);
301 skb_list_del_init(skb);
302 skb = ip6_rcv_core(skb, dev, net);
306 if (curr_dev != dev || curr_net != net) {
307 /* dispatch old sublist */
308 if (!list_empty(&sublist))
309 ip6_sublist_rcv(&sublist, curr_dev, curr_net);
310 /* start new sublist */
311 INIT_LIST_HEAD(&sublist);
315 list_add_tail(&skb->list, &sublist);
317 /* dispatch final sublist */
318 ip6_sublist_rcv(&sublist, curr_dev, curr_net);
321 INDIRECT_CALLABLE_DECLARE(int udpv6_rcv(struct sk_buff *));
322 INDIRECT_CALLABLE_DECLARE(int tcp_v6_rcv(struct sk_buff *));
325 * Deliver the packet to the host
327 void ip6_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int nexthdr,
330 const struct inet6_protocol *ipprot;
331 struct inet6_dev *idev;
336 * Parse extension headers
340 idev = ip6_dst_idev(skb_dst(skb));
341 nhoff = IP6CB(skb)->nhoff;
343 if (!pskb_pull(skb, skb_transport_offset(skb)))
345 nexthdr = skb_network_header(skb)[nhoff];
349 raw = raw6_local_deliver(skb, nexthdr);
350 ipprot = rcu_dereference(inet6_protos[nexthdr]);
355 if (!(ipprot->flags & INET6_PROTO_FINAL)) {
356 /* Once we've seen a final protocol don't
357 * allow encapsulation on any non-final
358 * ones. This allows foo in UDP encapsulation
363 } else if (ipprot->flags & INET6_PROTO_FINAL) {
364 const struct ipv6hdr *hdr;
365 int sdif = inet6_sdif(skb);
366 struct net_device *dev;
368 /* Only do this once for first final protocol */
371 /* Free reference early: we don't need it any more,
372 and it may hold ip_conntrack module loaded
376 skb_postpull_rcsum(skb, skb_network_header(skb),
377 skb_network_header_len(skb));
380 /* skb->dev passed may be master dev for vrfs. */
382 dev = dev_get_by_index_rcu(net, sdif);
389 if (ipv6_addr_is_multicast(&hdr->daddr) &&
390 !ipv6_chk_mcast_addr(dev, &hdr->daddr,
392 !ipv6_is_mld(skb, nexthdr, skb_network_header_len(skb)))
395 if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
396 !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
399 ret = INDIRECT_CALL_2(ipprot->handler, tcp_v6_rcv, udpv6_rcv,
402 if (ipprot->flags & INET6_PROTO_FINAL) {
403 /* Not an extension header, most likely UDP
404 * encapsulation. Use return value as nexthdr
405 * protocol not nhoff (which presumably is
406 * not set by handler).
413 } else if (ret == 0) {
414 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
418 if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
419 __IP6_INC_STATS(net, idev,
420 IPSTATS_MIB_INUNKNOWNPROTOS);
421 icmpv6_send(skb, ICMPV6_PARAMPROB,
422 ICMPV6_UNK_NEXTHDR, nhoff);
426 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
433 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
437 static int ip6_input_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
440 ip6_protocol_deliver_rcu(net, skb, 0, false);
447 int ip6_input(struct sk_buff *skb)
449 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN,
450 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
453 EXPORT_SYMBOL_GPL(ip6_input);
455 int ip6_mc_input(struct sk_buff *skb)
457 int sdif = inet6_sdif(skb);
458 const struct ipv6hdr *hdr;
459 struct net_device *dev;
462 __IP6_UPD_PO_STATS(dev_net(skb_dst(skb)->dev),
463 __in6_dev_get_safely(skb->dev), IPSTATS_MIB_INMCAST,
466 /* skb->dev passed may be master dev for vrfs. */
469 dev = dev_get_by_index_rcu(dev_net(skb->dev), sdif);
480 deliver = ipv6_chk_mcast_addr(dev, &hdr->daddr, NULL);
484 #ifdef CONFIG_IPV6_MROUTE
486 * IPv6 multicast router mode is now supported ;)
488 if (atomic_read(&dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding) &&
489 !(ipv6_addr_type(&hdr->daddr) &
490 (IPV6_ADDR_LOOPBACK|IPV6_ADDR_LINKLOCAL)) &&
491 likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
493 * Okay, we try to forward - split and duplicate
496 struct sk_buff *skb2;
497 struct inet6_skb_parm *opt = IP6CB(skb);
500 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
501 /* Check if this is a mld message */
502 u8 nexthdr = hdr->nexthdr;
506 /* Check if the value of Router Alert
507 * is for MLD (0x0000).
509 if (opt->ra == htons(IPV6_OPT_ROUTERALERT_MLD)) {
512 if (!ipv6_ext_hdr(nexthdr)) {
516 offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
517 &nexthdr, &frag_off);
521 if (ipv6_is_mld(skb, nexthdr, offset))
526 /* unknown RA - process it normally */
530 skb2 = skb_clone(skb, GFP_ATOMIC);