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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Internet Control Message Protocol (ICMPv6)
4 * Linux INET6 implementation
5 *
6 * Authors:
7 * Pedro Roque <roque@di.fc.ul.pt>
8 *
9 * Based on net/ipv4/icmp.c
10 *
11 * RFC 1885
12 */
13
14/*
15 * Changes:
16 *
17 * Andi Kleen : exception handling
18 * Andi Kleen add rate limits. never reply to a icmp.
19 * add more length checks and other fixes.
20 * yoshfuji : ensure to sent parameter problem for
21 * fragments.
22 * YOSHIFUJI Hideaki @USAGI: added sysctl for icmp rate limit.
23 * Randy Dunlap and
24 * YOSHIFUJI Hideaki @USAGI: Per-interface statistics support
25 * Kazunori MIYAZAWA @USAGI: change output process to use ip6_append_data
26 */
27
28#define pr_fmt(fmt) "IPv6: " fmt
29
30#include <linux/module.h>
31#include <linux/errno.h>
32#include <linux/types.h>
33#include <linux/socket.h>
34#include <linux/in.h>
35#include <linux/kernel.h>
36#include <linux/sockios.h>
37#include <linux/net.h>
38#include <linux/skbuff.h>
39#include <linux/init.h>
40#include <linux/netfilter.h>
41#include <linux/slab.h>
42
43#ifdef CONFIG_SYSCTL
44#include <linux/sysctl.h>
45#endif
46
47#include <linux/inet.h>
48#include <linux/netdevice.h>
49#include <linux/icmpv6.h>
50
51#include <net/ip.h>
52#include <net/sock.h>
53
54#include <net/ipv6.h>
55#include <net/ip6_checksum.h>
56#include <net/ping.h>
57#include <net/protocol.h>
58#include <net/raw.h>
59#include <net/rawv6.h>
60#include <net/seg6.h>
61#include <net/transp_v6.h>
62#include <net/ip6_route.h>
63#include <net/addrconf.h>
64#include <net/icmp.h>
65#include <net/xfrm.h>
66#include <net/inet_common.h>
67#include <net/dsfield.h>
68#include <net/l3mdev.h>
69
70#include <linux/uaccess.h>
71
72static DEFINE_PER_CPU(struct sock *, ipv6_icmp_sk);
73
74static int icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
75 u8 type, u8 code, int offset, __be32 info)
76{
77 /* icmpv6_notify checks 8 bytes can be pulled, icmp6hdr is 8 bytes */
78 struct icmp6hdr *icmp6 = (struct icmp6hdr *) (skb->data + offset);
79 struct net *net = dev_net(skb->dev);
80
81 if (type == ICMPV6_PKT_TOOBIG)
82 ip6_update_pmtu(skb, net, info, skb->dev->ifindex, 0, sock_net_uid(net, NULL));
83 else if (type == NDISC_REDIRECT)
84 ip6_redirect(skb, net, skb->dev->ifindex, 0,
85 sock_net_uid(net, NULL));
86
87 if (!(type & ICMPV6_INFOMSG_MASK))
88 if (icmp6->icmp6_type == ICMPV6_ECHO_REQUEST)
89 ping_err(skb, offset, ntohl(info));
90
91 return 0;
92}
93
94static int icmpv6_rcv(struct sk_buff *skb);
95
96static const struct inet6_protocol icmpv6_protocol = {
97 .handler = icmpv6_rcv,
98 .err_handler = icmpv6_err,
99 .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
100};
101
102/* Called with BH disabled */
103static struct sock *icmpv6_xmit_lock(struct net *net)
104{
105 struct sock *sk;
106
107 sk = this_cpu_read(ipv6_icmp_sk);
108 if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
109 /* This can happen if the output path (f.e. SIT or
110 * ip6ip6 tunnel) signals dst_link_failure() for an
111 * outgoing ICMP6 packet.
112 */
113 return NULL;
114 }
115 sock_net_set(sk, net);
116 return sk;
117}
118
119static void icmpv6_xmit_unlock(struct sock *sk)
120{
121 sock_net_set(sk, &init_net);
122 spin_unlock(&sk->sk_lock.slock);
123}
124
125/*
126 * Figure out, may we reply to this packet with icmp error.
127 *
128 * We do not reply, if:
129 * - it was icmp error message.
130 * - it is truncated, so that it is known, that protocol is ICMPV6
131 * (i.e. in the middle of some exthdr)
132 *
133 * --ANK (980726)
134 */
135
136static bool is_ineligible(const struct sk_buff *skb)
137{
138 int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
139 int len = skb->len - ptr;
140 __u8 nexthdr = ipv6_hdr(skb)->nexthdr;
141 __be16 frag_off;
142
143 if (len < 0)
144 return true;
145
146 ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off);
147 if (ptr < 0)
148 return false;
149 if (nexthdr == IPPROTO_ICMPV6) {
150 u8 _type, *tp;
151 tp = skb_header_pointer(skb,
152 ptr+offsetof(struct icmp6hdr, icmp6_type),
153 sizeof(_type), &_type);
154
155 /* Based on RFC 8200, Section 4.5 Fragment Header, return
156 * false if this is a fragment packet with no icmp header info.
157 */
158 if (!tp && frag_off != 0)
159 return false;
160 else if (!tp || !(*tp & ICMPV6_INFOMSG_MASK))
161 return true;
162 }
163 return false;
164}
165
166static bool icmpv6_mask_allow(struct net *net, int type)
167{
168 if (type > ICMPV6_MSG_MAX)
169 return true;
170
171 /* Limit if icmp type is set in ratemask. */
172 if (!test_bit(type, net->ipv6.sysctl.icmpv6_ratemask))
173 return true;
174
175 return false;
176}
177
178static bool icmpv6_global_allow(struct net *net, int type)
179{
180 if (icmpv6_mask_allow(net, type))
181 return true;
182
183 if (icmp_global_allow())
184 return true;
185
186 __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITGLOBAL);
187 return false;
188}
189
190/*
191 * Check the ICMP output rate limit
192 */
193static bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
194 struct flowi6 *fl6)
195{
196 struct net *net = sock_net(sk);
197 struct dst_entry *dst;
198 bool res = false;
199
200 if (icmpv6_mask_allow(net, type))
201 return true;
202
203 /*
204 * Look up the output route.
205 * XXX: perhaps the expire for routing entries cloned by
206 * this lookup should be more aggressive (not longer than timeout).
207 */
208 dst = ip6_route_output(net, sk, fl6);
209 if (dst->error) {
210 IP6_INC_STATS(net, ip6_dst_idev(dst),
211 IPSTATS_MIB_OUTNOROUTES);
212 } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
213 res = true;
214 } else {
215 struct rt6_info *rt = (struct rt6_info *)dst;
216 int tmo = net->ipv6.sysctl.icmpv6_time;
217 struct inet_peer *peer;
218
219 /* Give more bandwidth to wider prefixes. */
220 if (rt->rt6i_dst.plen < 128)
221 tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
222
223 peer = inet_getpeer_v6(net->ipv6.peers, &fl6->daddr, 1);
224 res = inet_peer_xrlim_allow(peer, tmo);
225 if (peer)
226 inet_putpeer(peer);
227 }
228 if (!res)
229 __ICMP6_INC_STATS(net, ip6_dst_idev(dst),
230 ICMP6_MIB_RATELIMITHOST);
231 dst_release(dst);
232 return res;
233}
234
235static bool icmpv6_rt_has_prefsrc(struct sock *sk, u8 type,
236 struct flowi6 *fl6)
237{
238 struct net *net = sock_net(sk);
239 struct dst_entry *dst;
240 bool res = false;
241
242 dst = ip6_route_output(net, sk, fl6);
243 if (!dst->error) {
244 struct rt6_info *rt = (struct rt6_info *)dst;
245 struct in6_addr prefsrc;
246
247 rt6_get_prefsrc(rt, &prefsrc);
248 res = !ipv6_addr_any(&prefsrc);
249 }
250 dst_release(dst);
251 return res;
252}
253
254/*
255 * an inline helper for the "simple" if statement below
256 * checks if parameter problem report is caused by an
257 * unrecognized IPv6 option that has the Option Type
258 * highest-order two bits set to 10
259 */
260
261static bool opt_unrec(struct sk_buff *skb, __u32 offset)
262{
263 u8 _optval, *op;
264
265 offset += skb_network_offset(skb);
266 op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
267 if (!op)
268 return true;
269 return (*op & 0xC0) == 0x80;
270}
271
272void icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6,
273 struct icmp6hdr *thdr, int len)
274{
275 struct sk_buff *skb;
276 struct icmp6hdr *icmp6h;
277
278 skb = skb_peek(&sk->sk_write_queue);
279 if (!skb)
280 return;
281
282 icmp6h = icmp6_hdr(skb);
283 memcpy(icmp6h, thdr, sizeof(struct icmp6hdr));
284 icmp6h->icmp6_cksum = 0;
285
286 if (skb_queue_len(&sk->sk_write_queue) == 1) {
287 skb->csum = csum_partial(icmp6h,
288 sizeof(struct icmp6hdr), skb->csum);
289 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
290 &fl6->daddr,
291 len, fl6->flowi6_proto,
292 skb->csum);
293 } else {
294 __wsum tmp_csum = 0;
295
296 skb_queue_walk(&sk->sk_write_queue, skb) {
297 tmp_csum = csum_add(tmp_csum, skb->csum);
298 }
299
300 tmp_csum = csum_partial(icmp6h,
301 sizeof(struct icmp6hdr), tmp_csum);
302 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
303 &fl6->daddr,
304 len, fl6->flowi6_proto,
305 tmp_csum);
306 }
307 ip6_push_pending_frames(sk);
308}
309
310struct icmpv6_msg {
311 struct sk_buff *skb;
312 int offset;
313 uint8_t type;
314};
315
316static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
317{
318 struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
319 struct sk_buff *org_skb = msg->skb;
320 __wsum csum;
321
322 csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
323 to, len);
324 skb->csum = csum_block_add(skb->csum, csum, odd);
325 if (!(msg->type & ICMPV6_INFOMSG_MASK))
326 nf_ct_attach(skb, org_skb);
327 return 0;
328}
329
330#if IS_ENABLED(CONFIG_IPV6_MIP6)
331static void mip6_addr_swap(struct sk_buff *skb, const struct inet6_skb_parm *opt)
332{
333 struct ipv6hdr *iph = ipv6_hdr(skb);
334 struct ipv6_destopt_hao *hao;
335 int off;
336
337 if (opt->dsthao) {
338 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
339 if (likely(off >= 0)) {
340 hao = (struct ipv6_destopt_hao *)
341 (skb_network_header(skb) + off);
342 swap(iph->saddr, hao->addr);
343 }
344 }
345}
346#else
347static inline void mip6_addr_swap(struct sk_buff *skb, const struct inet6_skb_parm *opt) {}
348#endif
349
350static struct dst_entry *icmpv6_route_lookup(struct net *net,
351 struct sk_buff *skb,
352 struct sock *sk,
353 struct flowi6 *fl6)
354{
355 struct dst_entry *dst, *dst2;
356 struct flowi6 fl2;
357 int err;
358
359 err = ip6_dst_lookup(net, sk, &dst, fl6);
360 if (err)
361 return ERR_PTR(err);
362
363 /*
364 * We won't send icmp if the destination is known
365 * anycast unless we need to treat anycast as unicast.
366 */
367 if (!READ_ONCE(net->ipv6.sysctl.icmpv6_error_anycast_as_unicast) &&
368 ipv6_anycast_destination(dst, &fl6->daddr)) {
369 net_dbg_ratelimited("icmp6_send: acast source\n");
370 dst_release(dst);
371 return ERR_PTR(-EINVAL);
372 }
373
374 /* No need to clone since we're just using its address. */
375 dst2 = dst;
376
377 dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0);
378 if (!IS_ERR(dst)) {
379 if (dst != dst2)
380 return dst;
381 } else {
382 if (PTR_ERR(dst) == -EPERM)
383 dst = NULL;
384 else
385 return dst;
386 }
387
388 err = xfrm_decode_session_reverse(net, skb, flowi6_to_flowi(&fl2), AF_INET6);
389 if (err)
390 goto relookup_failed;
391
392 err = ip6_dst_lookup(net, sk, &dst2, &fl2);
393 if (err)
394 goto relookup_failed;
395
396 dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP);
397 if (!IS_ERR(dst2)) {
398 dst_release(dst);
399 dst = dst2;
400 } else {
401 err = PTR_ERR(dst2);
402 if (err == -EPERM) {
403 dst_release(dst);
404 return dst2;
405 } else
406 goto relookup_failed;
407 }
408
409relookup_failed:
410 if (dst)
411 return dst;
412 return ERR_PTR(err);
413}
414
415static struct net_device *icmp6_dev(const struct sk_buff *skb)
416{
417 struct net_device *dev = skb->dev;
418
419 /* for local traffic to local address, skb dev is the loopback
420 * device. Check if there is a dst attached to the skb and if so
421 * get the real device index. Same is needed for replies to a link
422 * local address on a device enslaved to an L3 master device
423 */
424 if (unlikely(dev->ifindex == LOOPBACK_IFINDEX || netif_is_l3_master(skb->dev))) {
425 const struct rt6_info *rt6 = skb_rt6_info(skb);
426
427 /* The destination could be an external IP in Ext Hdr (SRv6, RPL, etc.),
428 * and ip6_null_entry could be set to skb if no route is found.
429 */
430 if (rt6 && rt6->rt6i_idev)
431 dev = rt6->rt6i_idev->dev;
432 }
433
434 return dev;
435}
436
437static int icmp6_iif(const struct sk_buff *skb)
438{
439 return icmp6_dev(skb)->ifindex;
440}
441
442/*
443 * Send an ICMP message in response to a packet in error
444 */
445void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
446 const struct in6_addr *force_saddr,
447 const struct inet6_skb_parm *parm)
448{
449 struct inet6_dev *idev = NULL;
450 struct ipv6hdr *hdr = ipv6_hdr(skb);
451 struct sock *sk;
452 struct net *net;
453 struct ipv6_pinfo *np;
454 const struct in6_addr *saddr = NULL;
455 struct dst_entry *dst;
456 struct icmp6hdr tmp_hdr;
457 struct flowi6 fl6;
458 struct icmpv6_msg msg;
459 struct ipcm6_cookie ipc6;
460 int iif = 0;
461 int addr_type = 0;
462 int len;
463 u32 mark;
464
465 if ((u8 *)hdr < skb->head ||
466 (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb))
467 return;
468
469 if (!skb->dev)
470 return;
471 net = dev_net(skb->dev);
472 mark = IP6_REPLY_MARK(net, skb->mark);
473 /*
474 * Make sure we respect the rules
475 * i.e. RFC 1885 2.4(e)
476 * Rule (e.1) is enforced by not using icmp6_send
477 * in any code that processes icmp errors.
478 */
479 addr_type = ipv6_addr_type(&hdr->daddr);
480
481 if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0) ||
482 ipv6_chk_acast_addr_src(net, skb->dev, &hdr->daddr))
483 saddr = &hdr->daddr;
484
485 /*
486 * Dest addr check
487 */
488
489 if (addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST) {
490 if (type != ICMPV6_PKT_TOOBIG &&
491 !(type == ICMPV6_PARAMPROB &&
492 code == ICMPV6_UNK_OPTION &&
493 (opt_unrec(skb, info))))
494 return;
495
496 saddr = NULL;
497 }
498
499 addr_type = ipv6_addr_type(&hdr->saddr);
500
501 /*
502 * Source addr check
503 */
504
505 if (__ipv6_addr_needs_scope_id(addr_type)) {
506 iif = icmp6_iif(skb);
507 } else {
508 /*
509 * The source device is used for looking up which routing table
510 * to use for sending an ICMP error.
511 */
512 iif = l3mdev_master_ifindex(skb->dev);
513 }
514
515 /*
516 * Must not send error if the source does not uniquely
517 * identify a single node (RFC2463 Section 2.4).
518 * We check unspecified / multicast addresses here,
519 * and anycast addresses will be checked later.
520 */
521 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
522 net_dbg_ratelimited("icmp6_send: addr_any/mcast source [%pI6c > %pI6c]\n",
523 &hdr->saddr, &hdr->daddr);
524 return;
525 }
526
527 /*
528 * Never answer to a ICMP packet.
529 */
530 if (is_ineligible(skb)) {
531 net_dbg_ratelimited("icmp6_send: no reply to icmp error [%pI6c > %pI6c]\n",
532 &hdr->saddr, &hdr->daddr);
533 return;
534 }
535
536 /* Needed by both icmp_global_allow and icmpv6_xmit_lock */
537 local_bh_disable();
538
539 /* Check global sysctl_icmp_msgs_per_sec ratelimit */
540 if (!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, type))
541 goto out_bh_enable;
542
543 mip6_addr_swap(skb, parm);
544
545 sk = icmpv6_xmit_lock(net);
546 if (!sk)
547 goto out_bh_enable;
548
549 memset(&fl6, 0, sizeof(fl6));
550 fl6.flowi6_proto = IPPROTO_ICMPV6;
551 fl6.daddr = hdr->saddr;
552 if (force_saddr)
553 saddr = force_saddr;
554 if (saddr) {
555 fl6.saddr = *saddr;
556 } else if (!icmpv6_rt_has_prefsrc(sk, type, &fl6)) {
557 /* select a more meaningful saddr from input if */
558 struct net_device *in_netdev;
559
560 in_netdev = dev_get_by_index(net, parm->iif);
561 if (in_netdev) {
562 ipv6_dev_get_saddr(net, in_netdev, &fl6.daddr,
563 inet6_sk(sk)->srcprefs,
564 &fl6.saddr);
565 dev_put(in_netdev);
566 }
567 }
568 fl6.flowi6_mark = mark;
569 fl6.flowi6_oif = iif;
570 fl6.fl6_icmp_type = type;
571 fl6.fl6_icmp_code = code;
572 fl6.flowi6_uid = sock_net_uid(net, NULL);
573 fl6.mp_hash = rt6_multipath_hash(net, &fl6, skb, NULL);
574 security_skb_classify_flow(skb, flowi6_to_flowi_common(&fl6));
575
576 np = inet6_sk(sk);
577
578 if (!icmpv6_xrlim_allow(sk, type, &fl6))
579 goto out;
580
581 tmp_hdr.icmp6_type = type;
582 tmp_hdr.icmp6_code = code;
583 tmp_hdr.icmp6_cksum = 0;
584 tmp_hdr.icmp6_pointer = htonl(info);
585
586 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
587 fl6.flowi6_oif = READ_ONCE(np->mcast_oif);
588 else if (!fl6.flowi6_oif)
589 fl6.flowi6_oif = READ_ONCE(np->ucast_oif);
590
591 ipcm6_init_sk(&ipc6, sk);
592 ipc6.sockc.mark = mark;
593 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
594
595 dst = icmpv6_route_lookup(net, skb, sk, &fl6);
596 if (IS_ERR(dst))
597 goto out;
598
599 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
600
601 msg.skb = skb;
602 msg.offset = skb_network_offset(skb);
603 msg.type = type;
604
605 len = skb->len - msg.offset;
606 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(struct icmp6hdr));
607 if (len < 0) {
608 net_dbg_ratelimited("icmp: len problem [%pI6c > %pI6c]\n",
609 &hdr->saddr, &hdr->daddr);
610 goto out_dst_release;
611 }
612
613 rcu_read_lock();
614 idev = __in6_dev_get(skb->dev);
615
616 if (ip6_append_data(sk, icmpv6_getfrag, &msg,
617 len + sizeof(struct icmp6hdr),
618 sizeof(struct icmp6hdr),
619 &ipc6, &fl6, (struct rt6_info *)dst,
620 MSG_DONTWAIT)) {
621 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS);
622 ip6_flush_pending_frames(sk);
623 } else {
624 icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
625 len + sizeof(struct icmp6hdr));
626 }
627 rcu_read_unlock();
628out_dst_release:
629 dst_release(dst);
630out:
631 icmpv6_xmit_unlock(sk);
632out_bh_enable:
633 local_bh_enable();
634}
635EXPORT_SYMBOL(icmp6_send);
636
637/* Slightly more convenient version of icmp6_send with drop reasons.
638 */
639void icmpv6_param_prob_reason(struct sk_buff *skb, u8 code, int pos,
640 enum skb_drop_reason reason)
641{
642 icmp6_send(skb, ICMPV6_PARAMPROB, code, pos, NULL, IP6CB(skb));
643 kfree_skb_reason(skb, reason);
644}
645
646/* Generate icmpv6 with type/code ICMPV6_DEST_UNREACH/ICMPV6_ADDR_UNREACH
647 * if sufficient data bytes are available
648 * @nhs is the size of the tunnel header(s) :
649 * Either an IPv4 header for SIT encap
650 * an IPv4 header + GRE header for GRE encap
651 */
652int ip6_err_gen_icmpv6_unreach(struct sk_buff *skb, int nhs, int type,
653 unsigned int data_len)
654{
655 struct in6_addr temp_saddr;
656 struct rt6_info *rt;
657 struct sk_buff *skb2;
658 u32 info = 0;
659
660 if (!pskb_may_pull(skb, nhs + sizeof(struct ipv6hdr) + 8))
661 return 1;
662
663 /* RFC 4884 (partial) support for ICMP extensions */
664 if (data_len < 128 || (data_len & 7) || skb->len < data_len)
665 data_len = 0;
666
667 skb2 = data_len ? skb_copy(skb, GFP_ATOMIC) : skb_clone(skb, GFP_ATOMIC);
668
669 if (!skb2)
670 return 1;
671
672 skb_dst_drop(skb2);
673 skb_pull(skb2, nhs);
674 skb_reset_network_header(skb2);
675
676 rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr, NULL, 0,
677 skb, 0);
678
679 if (rt && rt->dst.dev)
680 skb2->dev = rt->dst.dev;
681
682 ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr, &temp_saddr);
683
684 if (data_len) {
685 /* RFC 4884 (partial) support :
686 * insert 0 padding at the end, before the extensions
687 */
688 __skb_push(skb2, nhs);
689 skb_reset_network_header(skb2);
690 memmove(skb2->data, skb2->data + nhs, data_len - nhs);
691 memset(skb2->data + data_len - nhs, 0, nhs);
692 /* RFC 4884 4.5 : Length is measured in 64-bit words,
693 * and stored in reserved[0]
694 */
695 info = (data_len/8) << 24;
696 }
697 if (type == ICMP_TIME_EXCEEDED)
698 icmp6_send(skb2, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
699 info, &temp_saddr, IP6CB(skb2));
700 else
701 icmp6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH,
702 info, &temp_saddr, IP6CB(skb2));
703 if (rt)
704 ip6_rt_put(rt);
705
706 kfree_skb(skb2);
707
708 return 0;
709}
710EXPORT_SYMBOL(ip6_err_gen_icmpv6_unreach);
711
712static enum skb_drop_reason icmpv6_echo_reply(struct sk_buff *skb)
713{
714 struct net *net = dev_net(skb->dev);
715 struct sock *sk;
716 struct inet6_dev *idev;
717 struct ipv6_pinfo *np;
718 const struct in6_addr *saddr = NULL;
719 struct icmp6hdr *icmph = icmp6_hdr(skb);
720 struct icmp6hdr tmp_hdr;
721 struct flowi6 fl6;
722 struct icmpv6_msg msg;
723 struct dst_entry *dst;
724 struct ipcm6_cookie ipc6;
725 u32 mark = IP6_REPLY_MARK(net, skb->mark);
726 SKB_DR(reason);
727 bool acast;
728 u8 type;
729
730 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) &&
731 net->ipv6.sysctl.icmpv6_echo_ignore_multicast)
732 return reason;
733
734 saddr = &ipv6_hdr(skb)->daddr;
735
736 acast = ipv6_anycast_destination(skb_dst(skb), saddr);
737 if (acast && net->ipv6.sysctl.icmpv6_echo_ignore_anycast)
738 return reason;
739
740 if (!ipv6_unicast_destination(skb) &&
741 !(net->ipv6.sysctl.anycast_src_echo_reply && acast))
742 saddr = NULL;
743
744 if (icmph->icmp6_type == ICMPV6_EXT_ECHO_REQUEST)
745 type = ICMPV6_EXT_ECHO_REPLY;
746 else
747 type = ICMPV6_ECHO_REPLY;
748
749 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
750 tmp_hdr.icmp6_type = type;
751
752 memset(&fl6, 0, sizeof(fl6));
753 if (net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_ICMPV6_ECHO_REPLIES)
754 fl6.flowlabel = ip6_flowlabel(ipv6_hdr(skb));
755
756 fl6.flowi6_proto = IPPROTO_ICMPV6;
757 fl6.daddr = ipv6_hdr(skb)->saddr;
758 if (saddr)
759 fl6.saddr = *saddr;
760 fl6.flowi6_oif = icmp6_iif(skb);
761 fl6.fl6_icmp_type = type;
762 fl6.flowi6_mark = mark;
763 fl6.flowi6_uid = sock_net_uid(net, NULL);
764 security_skb_classify_flow(skb, flowi6_to_flowi_common(&fl6));
765
766 local_bh_disable();
767 sk = icmpv6_xmit_lock(net);
768 if (!sk)
769 goto out_bh_enable;
770 np = inet6_sk(sk);
771
772 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
773 fl6.flowi6_oif = READ_ONCE(np->mcast_oif);
774 else if (!fl6.flowi6_oif)
775 fl6.flowi6_oif = READ_ONCE(np->ucast_oif);
776
777 if (ip6_dst_lookup(net, sk, &dst, &fl6))
778 goto out;
779 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
780 if (IS_ERR(dst))
781 goto out;
782
783 /* Check the ratelimit */
784 if ((!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, ICMPV6_ECHO_REPLY)) ||
785 !icmpv6_xrlim_allow(sk, ICMPV6_ECHO_REPLY, &fl6))
786 goto out_dst_release;
787
788 idev = __in6_dev_get(skb->dev);
789
790 msg.skb = skb;
791 msg.offset = 0;
792 msg.type = type;
793
794 ipcm6_init_sk(&ipc6, sk);
795 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
796 ipc6.tclass = ipv6_get_dsfield(ipv6_hdr(skb));
797 ipc6.sockc.mark = mark;
798
799 if (icmph->icmp6_type == ICMPV6_EXT_ECHO_REQUEST)
800 if (!icmp_build_probe(skb, (struct icmphdr *)&tmp_hdr))
801 goto out_dst_release;
802
803 if (ip6_append_data(sk, icmpv6_getfrag, &msg,
804 skb->len + sizeof(struct icmp6hdr),
805 sizeof(struct icmp6hdr), &ipc6, &fl6,
806 (struct rt6_info *)dst, MSG_DONTWAIT)) {
807 __ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS);
808 ip6_flush_pending_frames(sk);
809 } else {
810 icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
811 skb->len + sizeof(struct icmp6hdr));
812 reason = SKB_CONSUMED;
813 }
814out_dst_release:
815 dst_release(dst);
816out:
817 icmpv6_xmit_unlock(sk);
818out_bh_enable:
819 local_bh_enable();
820 return reason;
821}
822
823enum skb_drop_reason icmpv6_notify(struct sk_buff *skb, u8 type,
824 u8 code, __be32 info)
825{
826 struct inet6_skb_parm *opt = IP6CB(skb);
827 struct net *net = dev_net(skb->dev);
828 const struct inet6_protocol *ipprot;
829 enum skb_drop_reason reason;
830 int inner_offset;
831 __be16 frag_off;
832 u8 nexthdr;
833
834 reason = pskb_may_pull_reason(skb, sizeof(struct ipv6hdr));
835 if (reason != SKB_NOT_DROPPED_YET)
836 goto out;
837
838 seg6_icmp_srh(skb, opt);
839
840 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
841 if (ipv6_ext_hdr(nexthdr)) {
842 /* now skip over extension headers */
843 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
844 &nexthdr, &frag_off);
845 if (inner_offset < 0) {
846 SKB_DR_SET(reason, IPV6_BAD_EXTHDR);
847 goto out;
848 }
849 } else {
850 inner_offset = sizeof(struct ipv6hdr);
851 }
852
853 /* Checkin header including 8 bytes of inner protocol header. */
854 reason = pskb_may_pull_reason(skb, inner_offset + 8);
855 if (reason != SKB_NOT_DROPPED_YET)
856 goto out;
857
858 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
859 Without this we will not able f.e. to make source routed
860 pmtu discovery.
861 Corresponding argument (opt) to notifiers is already added.
862 --ANK (980726)
863 */
864
865 ipprot = rcu_dereference(inet6_protos[nexthdr]);
866 if (ipprot && ipprot->err_handler)
867 ipprot->err_handler(skb, opt, type, code, inner_offset, info);
868
869 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
870 return SKB_CONSUMED;
871
872out:
873 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS);
874 return reason;
875}
876
877/*
878 * Handle icmp messages
879 */
880
881static int icmpv6_rcv(struct sk_buff *skb)
882{
883 enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
884 struct net *net = dev_net(skb->dev);
885 struct net_device *dev = icmp6_dev(skb);
886 struct inet6_dev *idev = __in6_dev_get(dev);
887 const struct in6_addr *saddr, *daddr;
888 struct icmp6hdr *hdr;
889 u8 type;
890
891 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
892 struct sec_path *sp = skb_sec_path(skb);
893 int nh;
894
895 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
896 XFRM_STATE_ICMP)) {
897 reason = SKB_DROP_REASON_XFRM_POLICY;
898 goto drop_no_count;
899 }
900
901 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr)))
902 goto drop_no_count;
903
904 nh = skb_network_offset(skb);
905 skb_set_network_header(skb, sizeof(*hdr));
906
907 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN,
908 skb)) {
909 reason = SKB_DROP_REASON_XFRM_POLICY;
910 goto drop_no_count;
911 }
912
913 skb_set_network_header(skb, nh);
914 }
915
916 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INMSGS);
917
918 saddr = &ipv6_hdr(skb)->saddr;
919 daddr = &ipv6_hdr(skb)->daddr;
920
921 if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) {
922 net_dbg_ratelimited("ICMPv6 checksum failed [%pI6c > %pI6c]\n",
923 saddr, daddr);
924 goto csum_error;
925 }
926
927 if (!pskb_pull(skb, sizeof(*hdr)))
928 goto discard_it;
929
930 hdr = icmp6_hdr(skb);
931
932 type = hdr->icmp6_type;
933
934 ICMP6MSGIN_INC_STATS(dev_net(dev), idev, type);
935
936 switch (type) {
937 case ICMPV6_ECHO_REQUEST:
938 if (!net->ipv6.sysctl.icmpv6_echo_ignore_all)
939 reason = icmpv6_echo_reply(skb);
940 break;
941 case ICMPV6_EXT_ECHO_REQUEST:
942 if (!net->ipv6.sysctl.icmpv6_echo_ignore_all &&
943 READ_ONCE(net->ipv4.sysctl_icmp_echo_enable_probe))
944 reason = icmpv6_echo_reply(skb);
945 break;
946
947 case ICMPV6_ECHO_REPLY:
948 reason = ping_rcv(skb);
949 break;
950
951 case ICMPV6_EXT_ECHO_REPLY:
952 reason = ping_rcv(skb);
953 break;
954
955 case ICMPV6_PKT_TOOBIG:
956 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
957 standard destination cache. Seems, only "advanced"
958 destination cache will allow to solve this problem
959 --ANK (980726)
960 */
961 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
962 goto discard_it;
963 hdr = icmp6_hdr(skb);
964
965 /* to notify */
966 fallthrough;
967 case ICMPV6_DEST_UNREACH:
968 case ICMPV6_TIME_EXCEED:
969 case ICMPV6_PARAMPROB:
970 reason = icmpv6_notify(skb, type, hdr->icmp6_code,
971 hdr->icmp6_mtu);
972 break;
973
974 case NDISC_ROUTER_SOLICITATION:
975 case NDISC_ROUTER_ADVERTISEMENT:
976 case NDISC_NEIGHBOUR_SOLICITATION:
977 case NDISC_NEIGHBOUR_ADVERTISEMENT:
978 case NDISC_REDIRECT:
979 reason = ndisc_rcv(skb);
980 break;
981
982 case ICMPV6_MGM_QUERY:
983 igmp6_event_query(skb);
984 return 0;
985
986 case ICMPV6_MGM_REPORT:
987 igmp6_event_report(skb);
988 return 0;
989
990 case ICMPV6_MGM_REDUCTION:
991 case ICMPV6_NI_QUERY:
992 case ICMPV6_NI_REPLY:
993 case ICMPV6_MLD2_REPORT:
994 case ICMPV6_DHAAD_REQUEST:
995 case ICMPV6_DHAAD_REPLY:
996 case ICMPV6_MOBILE_PREFIX_SOL:
997 case ICMPV6_MOBILE_PREFIX_ADV:
998 break;
999
1000 default:
1001 /* informational */
1002 if (type & ICMPV6_INFOMSG_MASK)
1003 break;
1004
1005 net_dbg_ratelimited("icmpv6: msg of unknown type [%pI6c > %pI6c]\n",
1006 saddr, daddr);
1007
1008 /*
1009 * error of unknown type.
1010 * must pass to upper level
1011 */
1012
1013 reason = icmpv6_notify(skb, type, hdr->icmp6_code,
1014 hdr->icmp6_mtu);
1015 }
1016
1017 /* until the v6 path can be better sorted assume failure and
1018 * preserve the status quo behaviour for the rest of the paths to here
1019 */
1020 if (reason)
1021 kfree_skb_reason(skb, reason);
1022 else
1023 consume_skb(skb);
1024
1025 return 0;
1026
1027csum_error:
1028 reason = SKB_DROP_REASON_ICMP_CSUM;
1029 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS);
1030discard_it:
1031 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INERRORS);
1032drop_no_count:
1033 kfree_skb_reason(skb, reason);
1034 return 0;
1035}
1036
1037void icmpv6_flow_init(const struct sock *sk, struct flowi6 *fl6, u8 type,
1038 const struct in6_addr *saddr,
1039 const struct in6_addr *daddr, int oif)
1040{
1041 memset(fl6, 0, sizeof(*fl6));
1042 fl6->saddr = *saddr;
1043 fl6->daddr = *daddr;
1044 fl6->flowi6_proto = IPPROTO_ICMPV6;
1045 fl6->fl6_icmp_type = type;
1046 fl6->fl6_icmp_code = 0;
1047 fl6->flowi6_oif = oif;
1048 security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6));
1049}
1050
1051int __init icmpv6_init(void)
1052{
1053 struct sock *sk;
1054 int err, i;
1055
1056 for_each_possible_cpu(i) {
1057 err = inet_ctl_sock_create(&sk, PF_INET6,
1058 SOCK_RAW, IPPROTO_ICMPV6, &init_net);
1059 if (err < 0) {
1060 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n",
1061 err);
1062 return err;
1063 }
1064
1065 per_cpu(ipv6_icmp_sk, i) = sk;
1066
1067 /* Enough space for 2 64K ICMP packets, including
1068 * sk_buff struct overhead.
1069 */
1070 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
1071 }
1072
1073 err = -EAGAIN;
1074 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0)
1075 goto fail;
1076
1077 err = inet6_register_icmp_sender(icmp6_send);
1078 if (err)
1079 goto sender_reg_err;
1080 return 0;
1081
1082sender_reg_err:
1083 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
1084fail:
1085 pr_err("Failed to register ICMP6 protocol\n");
1086 return err;
1087}
1088
1089void icmpv6_cleanup(void)
1090{
1091 inet6_unregister_icmp_sender(icmp6_send);
1092 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
1093}
1094
1095
1096static const struct icmp6_err {
1097 int err;
1098 int fatal;
1099} tab_unreach[] = {
1100 { /* NOROUTE */
1101 .err = ENETUNREACH,
1102 .fatal = 0,
1103 },
1104 { /* ADM_PROHIBITED */
1105 .err = EACCES,
1106 .fatal = 1,
1107 },
1108 { /* Was NOT_NEIGHBOUR, now reserved */
1109 .err = EHOSTUNREACH,
1110 .fatal = 0,
1111 },
1112 { /* ADDR_UNREACH */
1113 .err = EHOSTUNREACH,
1114 .fatal = 0,
1115 },
1116 { /* PORT_UNREACH */
1117 .err = ECONNREFUSED,
1118 .fatal = 1,
1119 },
1120 { /* POLICY_FAIL */
1121 .err = EACCES,
1122 .fatal = 1,
1123 },
1124 { /* REJECT_ROUTE */
1125 .err = EACCES,
1126 .fatal = 1,
1127 },
1128};
1129
1130int icmpv6_err_convert(u8 type, u8 code, int *err)
1131{
1132 int fatal = 0;
1133
1134 *err = EPROTO;
1135
1136 switch (type) {
1137 case ICMPV6_DEST_UNREACH:
1138 fatal = 1;
1139 if (code < ARRAY_SIZE(tab_unreach)) {
1140 *err = tab_unreach[code].err;
1141 fatal = tab_unreach[code].fatal;
1142 }
1143 break;
1144
1145 case ICMPV6_PKT_TOOBIG:
1146 *err = EMSGSIZE;
1147 break;
1148
1149 case ICMPV6_PARAMPROB:
1150 *err = EPROTO;
1151 fatal = 1;
1152 break;
1153
1154 case ICMPV6_TIME_EXCEED:
1155 *err = EHOSTUNREACH;
1156 break;
1157 }
1158
1159 return fatal;
1160}
1161EXPORT_SYMBOL(icmpv6_err_convert);
1162
1163#ifdef CONFIG_SYSCTL
1164static struct ctl_table ipv6_icmp_table_template[] = {
1165 {
1166 .procname = "ratelimit",
1167 .data = &init_net.ipv6.sysctl.icmpv6_time,
1168 .maxlen = sizeof(int),
1169 .mode = 0644,
1170 .proc_handler = proc_dointvec_ms_jiffies,
1171 },
1172 {
1173 .procname = "echo_ignore_all",
1174 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_all,
1175 .maxlen = sizeof(u8),
1176 .mode = 0644,
1177 .proc_handler = proc_dou8vec_minmax,
1178 },
1179 {
1180 .procname = "echo_ignore_multicast",
1181 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_multicast,
1182 .maxlen = sizeof(u8),
1183 .mode = 0644,
1184 .proc_handler = proc_dou8vec_minmax,
1185 },
1186 {
1187 .procname = "echo_ignore_anycast",
1188 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_anycast,
1189 .maxlen = sizeof(u8),
1190 .mode = 0644,
1191 .proc_handler = proc_dou8vec_minmax,
1192 },
1193 {
1194 .procname = "ratemask",
1195 .data = &init_net.ipv6.sysctl.icmpv6_ratemask_ptr,
1196 .maxlen = ICMPV6_MSG_MAX + 1,
1197 .mode = 0644,
1198 .proc_handler = proc_do_large_bitmap,
1199 },
1200 {
1201 .procname = "error_anycast_as_unicast",
1202 .data = &init_net.ipv6.sysctl.icmpv6_error_anycast_as_unicast,
1203 .maxlen = sizeof(u8),
1204 .mode = 0644,
1205 .proc_handler = proc_dou8vec_minmax,
1206 .extra1 = SYSCTL_ZERO,
1207 .extra2 = SYSCTL_ONE,
1208 },
1209 { },
1210};
1211
1212struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
1213{
1214 struct ctl_table *table;
1215
1216 table = kmemdup(ipv6_icmp_table_template,
1217 sizeof(ipv6_icmp_table_template),
1218 GFP_KERNEL);
1219
1220 if (table) {
1221 table[0].data = &net->ipv6.sysctl.icmpv6_time;
1222 table[1].data = &net->ipv6.sysctl.icmpv6_echo_ignore_all;
1223 table[2].data = &net->ipv6.sysctl.icmpv6_echo_ignore_multicast;
1224 table[3].data = &net->ipv6.sysctl.icmpv6_echo_ignore_anycast;
1225 table[4].data = &net->ipv6.sysctl.icmpv6_ratemask_ptr;
1226 table[5].data = &net->ipv6.sysctl.icmpv6_error_anycast_as_unicast;
1227 }
1228 return table;
1229}
1230
1231size_t ipv6_icmp_sysctl_table_size(void)
1232{
1233 return ARRAY_SIZE(ipv6_icmp_table_template);
1234}
1235#endif
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Internet Control Message Protocol (ICMPv6)
4 * Linux INET6 implementation
5 *
6 * Authors:
7 * Pedro Roque <roque@di.fc.ul.pt>
8 *
9 * Based on net/ipv4/icmp.c
10 *
11 * RFC 1885
12 */
13
14/*
15 * Changes:
16 *
17 * Andi Kleen : exception handling
18 * Andi Kleen add rate limits. never reply to a icmp.
19 * add more length checks and other fixes.
20 * yoshfuji : ensure to sent parameter problem for
21 * fragments.
22 * YOSHIFUJI Hideaki @USAGI: added sysctl for icmp rate limit.
23 * Randy Dunlap and
24 * YOSHIFUJI Hideaki @USAGI: Per-interface statistics support
25 * Kazunori MIYAZAWA @USAGI: change output process to use ip6_append_data
26 */
27
28#define pr_fmt(fmt) "IPv6: " fmt
29
30#include <linux/module.h>
31#include <linux/errno.h>
32#include <linux/types.h>
33#include <linux/socket.h>
34#include <linux/in.h>
35#include <linux/kernel.h>
36#include <linux/sockios.h>
37#include <linux/net.h>
38#include <linux/skbuff.h>
39#include <linux/init.h>
40#include <linux/netfilter.h>
41#include <linux/slab.h>
42
43#ifdef CONFIG_SYSCTL
44#include <linux/sysctl.h>
45#endif
46
47#include <linux/inet.h>
48#include <linux/netdevice.h>
49#include <linux/icmpv6.h>
50
51#include <net/ip.h>
52#include <net/sock.h>
53
54#include <net/ipv6.h>
55#include <net/ip6_checksum.h>
56#include <net/ping.h>
57#include <net/protocol.h>
58#include <net/raw.h>
59#include <net/rawv6.h>
60#include <net/transp_v6.h>
61#include <net/ip6_route.h>
62#include <net/addrconf.h>
63#include <net/icmp.h>
64#include <net/xfrm.h>
65#include <net/inet_common.h>
66#include <net/dsfield.h>
67#include <net/l3mdev.h>
68
69#include <linux/uaccess.h>
70
71/*
72 * The ICMP socket(s). This is the most convenient way to flow control
73 * our ICMP output as well as maintain a clean interface throughout
74 * all layers. All Socketless IP sends will soon be gone.
75 *
76 * On SMP we have one ICMP socket per-cpu.
77 */
78static struct sock *icmpv6_sk(struct net *net)
79{
80 return this_cpu_read(*net->ipv6.icmp_sk);
81}
82
83static int icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
84 u8 type, u8 code, int offset, __be32 info)
85{
86 /* icmpv6_notify checks 8 bytes can be pulled, icmp6hdr is 8 bytes */
87 struct icmp6hdr *icmp6 = (struct icmp6hdr *) (skb->data + offset);
88 struct net *net = dev_net(skb->dev);
89
90 if (type == ICMPV6_PKT_TOOBIG)
91 ip6_update_pmtu(skb, net, info, skb->dev->ifindex, 0, sock_net_uid(net, NULL));
92 else if (type == NDISC_REDIRECT)
93 ip6_redirect(skb, net, skb->dev->ifindex, 0,
94 sock_net_uid(net, NULL));
95
96 if (!(type & ICMPV6_INFOMSG_MASK))
97 if (icmp6->icmp6_type == ICMPV6_ECHO_REQUEST)
98 ping_err(skb, offset, ntohl(info));
99
100 return 0;
101}
102
103static int icmpv6_rcv(struct sk_buff *skb);
104
105static const struct inet6_protocol icmpv6_protocol = {
106 .handler = icmpv6_rcv,
107 .err_handler = icmpv6_err,
108 .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
109};
110
111/* Called with BH disabled */
112static __inline__ struct sock *icmpv6_xmit_lock(struct net *net)
113{
114 struct sock *sk;
115
116 sk = icmpv6_sk(net);
117 if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
118 /* This can happen if the output path (f.e. SIT or
119 * ip6ip6 tunnel) signals dst_link_failure() for an
120 * outgoing ICMP6 packet.
121 */
122 return NULL;
123 }
124 return sk;
125}
126
127static __inline__ void icmpv6_xmit_unlock(struct sock *sk)
128{
129 spin_unlock(&sk->sk_lock.slock);
130}
131
132/*
133 * Figure out, may we reply to this packet with icmp error.
134 *
135 * We do not reply, if:
136 * - it was icmp error message.
137 * - it is truncated, so that it is known, that protocol is ICMPV6
138 * (i.e. in the middle of some exthdr)
139 *
140 * --ANK (980726)
141 */
142
143static bool is_ineligible(const struct sk_buff *skb)
144{
145 int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
146 int len = skb->len - ptr;
147 __u8 nexthdr = ipv6_hdr(skb)->nexthdr;
148 __be16 frag_off;
149
150 if (len < 0)
151 return true;
152
153 ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off);
154 if (ptr < 0)
155 return false;
156 if (nexthdr == IPPROTO_ICMPV6) {
157 u8 _type, *tp;
158 tp = skb_header_pointer(skb,
159 ptr+offsetof(struct icmp6hdr, icmp6_type),
160 sizeof(_type), &_type);
161 if (!tp || !(*tp & ICMPV6_INFOMSG_MASK))
162 return true;
163 }
164 return false;
165}
166
167static bool icmpv6_mask_allow(struct net *net, int type)
168{
169 if (type > ICMPV6_MSG_MAX)
170 return true;
171
172 /* Limit if icmp type is set in ratemask. */
173 if (!test_bit(type, net->ipv6.sysctl.icmpv6_ratemask))
174 return true;
175
176 return false;
177}
178
179static bool icmpv6_global_allow(struct net *net, int type)
180{
181 if (icmpv6_mask_allow(net, type))
182 return true;
183
184 if (icmp_global_allow())
185 return true;
186
187 return false;
188}
189
190/*
191 * Check the ICMP output rate limit
192 */
193static bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
194 struct flowi6 *fl6)
195{
196 struct net *net = sock_net(sk);
197 struct dst_entry *dst;
198 bool res = false;
199
200 if (icmpv6_mask_allow(net, type))
201 return true;
202
203 /*
204 * Look up the output route.
205 * XXX: perhaps the expire for routing entries cloned by
206 * this lookup should be more aggressive (not longer than timeout).
207 */
208 dst = ip6_route_output(net, sk, fl6);
209 if (dst->error) {
210 IP6_INC_STATS(net, ip6_dst_idev(dst),
211 IPSTATS_MIB_OUTNOROUTES);
212 } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
213 res = true;
214 } else {
215 struct rt6_info *rt = (struct rt6_info *)dst;
216 int tmo = net->ipv6.sysctl.icmpv6_time;
217 struct inet_peer *peer;
218
219 /* Give more bandwidth to wider prefixes. */
220 if (rt->rt6i_dst.plen < 128)
221 tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
222
223 peer = inet_getpeer_v6(net->ipv6.peers, &fl6->daddr, 1);
224 res = inet_peer_xrlim_allow(peer, tmo);
225 if (peer)
226 inet_putpeer(peer);
227 }
228 dst_release(dst);
229 return res;
230}
231
232/*
233 * an inline helper for the "simple" if statement below
234 * checks if parameter problem report is caused by an
235 * unrecognized IPv6 option that has the Option Type
236 * highest-order two bits set to 10
237 */
238
239static bool opt_unrec(struct sk_buff *skb, __u32 offset)
240{
241 u8 _optval, *op;
242
243 offset += skb_network_offset(skb);
244 op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
245 if (!op)
246 return true;
247 return (*op & 0xC0) == 0x80;
248}
249
250void icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6,
251 struct icmp6hdr *thdr, int len)
252{
253 struct sk_buff *skb;
254 struct icmp6hdr *icmp6h;
255
256 skb = skb_peek(&sk->sk_write_queue);
257 if (!skb)
258 return;
259
260 icmp6h = icmp6_hdr(skb);
261 memcpy(icmp6h, thdr, sizeof(struct icmp6hdr));
262 icmp6h->icmp6_cksum = 0;
263
264 if (skb_queue_len(&sk->sk_write_queue) == 1) {
265 skb->csum = csum_partial(icmp6h,
266 sizeof(struct icmp6hdr), skb->csum);
267 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
268 &fl6->daddr,
269 len, fl6->flowi6_proto,
270 skb->csum);
271 } else {
272 __wsum tmp_csum = 0;
273
274 skb_queue_walk(&sk->sk_write_queue, skb) {
275 tmp_csum = csum_add(tmp_csum, skb->csum);
276 }
277
278 tmp_csum = csum_partial(icmp6h,
279 sizeof(struct icmp6hdr), tmp_csum);
280 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
281 &fl6->daddr,
282 len, fl6->flowi6_proto,
283 tmp_csum);
284 }
285 ip6_push_pending_frames(sk);
286}
287
288struct icmpv6_msg {
289 struct sk_buff *skb;
290 int offset;
291 uint8_t type;
292};
293
294static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
295{
296 struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
297 struct sk_buff *org_skb = msg->skb;
298 __wsum csum = 0;
299
300 csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
301 to, len, csum);
302 skb->csum = csum_block_add(skb->csum, csum, odd);
303 if (!(msg->type & ICMPV6_INFOMSG_MASK))
304 nf_ct_attach(skb, org_skb);
305 return 0;
306}
307
308#if IS_ENABLED(CONFIG_IPV6_MIP6)
309static void mip6_addr_swap(struct sk_buff *skb)
310{
311 struct ipv6hdr *iph = ipv6_hdr(skb);
312 struct inet6_skb_parm *opt = IP6CB(skb);
313 struct ipv6_destopt_hao *hao;
314 struct in6_addr tmp;
315 int off;
316
317 if (opt->dsthao) {
318 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
319 if (likely(off >= 0)) {
320 hao = (struct ipv6_destopt_hao *)
321 (skb_network_header(skb) + off);
322 tmp = iph->saddr;
323 iph->saddr = hao->addr;
324 hao->addr = tmp;
325 }
326 }
327}
328#else
329static inline void mip6_addr_swap(struct sk_buff *skb) {}
330#endif
331
332static struct dst_entry *icmpv6_route_lookup(struct net *net,
333 struct sk_buff *skb,
334 struct sock *sk,
335 struct flowi6 *fl6)
336{
337 struct dst_entry *dst, *dst2;
338 struct flowi6 fl2;
339 int err;
340
341 err = ip6_dst_lookup(net, sk, &dst, fl6);
342 if (err)
343 return ERR_PTR(err);
344
345 /*
346 * We won't send icmp if the destination is known
347 * anycast.
348 */
349 if (ipv6_anycast_destination(dst, &fl6->daddr)) {
350 net_dbg_ratelimited("icmp6_send: acast source\n");
351 dst_release(dst);
352 return ERR_PTR(-EINVAL);
353 }
354
355 /* No need to clone since we're just using its address. */
356 dst2 = dst;
357
358 dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0);
359 if (!IS_ERR(dst)) {
360 if (dst != dst2)
361 return dst;
362 } else {
363 if (PTR_ERR(dst) == -EPERM)
364 dst = NULL;
365 else
366 return dst;
367 }
368
369 err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6);
370 if (err)
371 goto relookup_failed;
372
373 err = ip6_dst_lookup(net, sk, &dst2, &fl2);
374 if (err)
375 goto relookup_failed;
376
377 dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP);
378 if (!IS_ERR(dst2)) {
379 dst_release(dst);
380 dst = dst2;
381 } else {
382 err = PTR_ERR(dst2);
383 if (err == -EPERM) {
384 dst_release(dst);
385 return dst2;
386 } else
387 goto relookup_failed;
388 }
389
390relookup_failed:
391 if (dst)
392 return dst;
393 return ERR_PTR(err);
394}
395
396static struct net_device *icmp6_dev(const struct sk_buff *skb)
397{
398 struct net_device *dev = skb->dev;
399
400 /* for local traffic to local address, skb dev is the loopback
401 * device. Check if there is a dst attached to the skb and if so
402 * get the real device index. Same is needed for replies to a link
403 * local address on a device enslaved to an L3 master device
404 */
405 if (unlikely(dev->ifindex == LOOPBACK_IFINDEX || netif_is_l3_master(skb->dev))) {
406 const struct rt6_info *rt6 = skb_rt6_info(skb);
407
408 if (rt6)
409 dev = rt6->rt6i_idev->dev;
410 }
411
412 return dev;
413}
414
415static int icmp6_iif(const struct sk_buff *skb)
416{
417 return icmp6_dev(skb)->ifindex;
418}
419
420/*
421 * Send an ICMP message in response to a packet in error
422 */
423static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
424 const struct in6_addr *force_saddr)
425{
426 struct inet6_dev *idev = NULL;
427 struct ipv6hdr *hdr = ipv6_hdr(skb);
428 struct sock *sk;
429 struct net *net;
430 struct ipv6_pinfo *np;
431 const struct in6_addr *saddr = NULL;
432 struct dst_entry *dst;
433 struct icmp6hdr tmp_hdr;
434 struct flowi6 fl6;
435 struct icmpv6_msg msg;
436 struct ipcm6_cookie ipc6;
437 int iif = 0;
438 int addr_type = 0;
439 int len;
440 u32 mark;
441
442 if ((u8 *)hdr < skb->head ||
443 (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb))
444 return;
445
446 if (!skb->dev)
447 return;
448 net = dev_net(skb->dev);
449 mark = IP6_REPLY_MARK(net, skb->mark);
450 /*
451 * Make sure we respect the rules
452 * i.e. RFC 1885 2.4(e)
453 * Rule (e.1) is enforced by not using icmp6_send
454 * in any code that processes icmp errors.
455 */
456 addr_type = ipv6_addr_type(&hdr->daddr);
457
458 if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0) ||
459 ipv6_chk_acast_addr_src(net, skb->dev, &hdr->daddr))
460 saddr = &hdr->daddr;
461
462 /*
463 * Dest addr check
464 */
465
466 if (addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST) {
467 if (type != ICMPV6_PKT_TOOBIG &&
468 !(type == ICMPV6_PARAMPROB &&
469 code == ICMPV6_UNK_OPTION &&
470 (opt_unrec(skb, info))))
471 return;
472
473 saddr = NULL;
474 }
475
476 addr_type = ipv6_addr_type(&hdr->saddr);
477
478 /*
479 * Source addr check
480 */
481
482 if (__ipv6_addr_needs_scope_id(addr_type)) {
483 iif = icmp6_iif(skb);
484 } else {
485 dst = skb_dst(skb);
486 iif = l3mdev_master_ifindex(dst ? dst->dev : skb->dev);
487 }
488
489 /*
490 * Must not send error if the source does not uniquely
491 * identify a single node (RFC2463 Section 2.4).
492 * We check unspecified / multicast addresses here,
493 * and anycast addresses will be checked later.
494 */
495 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
496 net_dbg_ratelimited("icmp6_send: addr_any/mcast source [%pI6c > %pI6c]\n",
497 &hdr->saddr, &hdr->daddr);
498 return;
499 }
500
501 /*
502 * Never answer to a ICMP packet.
503 */
504 if (is_ineligible(skb)) {
505 net_dbg_ratelimited("icmp6_send: no reply to icmp error [%pI6c > %pI6c]\n",
506 &hdr->saddr, &hdr->daddr);
507 return;
508 }
509
510 /* Needed by both icmp_global_allow and icmpv6_xmit_lock */
511 local_bh_disable();
512
513 /* Check global sysctl_icmp_msgs_per_sec ratelimit */
514 if (!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, type))
515 goto out_bh_enable;
516
517 mip6_addr_swap(skb);
518
519 memset(&fl6, 0, sizeof(fl6));
520 fl6.flowi6_proto = IPPROTO_ICMPV6;
521 fl6.daddr = hdr->saddr;
522 if (force_saddr)
523 saddr = force_saddr;
524 if (saddr)
525 fl6.saddr = *saddr;
526 fl6.flowi6_mark = mark;
527 fl6.flowi6_oif = iif;
528 fl6.fl6_icmp_type = type;
529 fl6.fl6_icmp_code = code;
530 fl6.flowi6_uid = sock_net_uid(net, NULL);
531 fl6.mp_hash = rt6_multipath_hash(net, &fl6, skb, NULL);
532 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
533
534 sk = icmpv6_xmit_lock(net);
535 if (!sk)
536 goto out_bh_enable;
537
538 sk->sk_mark = mark;
539 np = inet6_sk(sk);
540
541 if (!icmpv6_xrlim_allow(sk, type, &fl6))
542 goto out;
543
544 tmp_hdr.icmp6_type = type;
545 tmp_hdr.icmp6_code = code;
546 tmp_hdr.icmp6_cksum = 0;
547 tmp_hdr.icmp6_pointer = htonl(info);
548
549 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
550 fl6.flowi6_oif = np->mcast_oif;
551 else if (!fl6.flowi6_oif)
552 fl6.flowi6_oif = np->ucast_oif;
553
554 ipcm6_init_sk(&ipc6, np);
555 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
556
557 dst = icmpv6_route_lookup(net, skb, sk, &fl6);
558 if (IS_ERR(dst))
559 goto out;
560
561 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
562
563 msg.skb = skb;
564 msg.offset = skb_network_offset(skb);
565 msg.type = type;
566
567 len = skb->len - msg.offset;
568 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(struct icmp6hdr));
569 if (len < 0) {
570 net_dbg_ratelimited("icmp: len problem [%pI6c > %pI6c]\n",
571 &hdr->saddr, &hdr->daddr);
572 goto out_dst_release;
573 }
574
575 rcu_read_lock();
576 idev = __in6_dev_get(skb->dev);
577
578 if (ip6_append_data(sk, icmpv6_getfrag, &msg,
579 len + sizeof(struct icmp6hdr),
580 sizeof(struct icmp6hdr),
581 &ipc6, &fl6, (struct rt6_info *)dst,
582 MSG_DONTWAIT)) {
583 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS);
584 ip6_flush_pending_frames(sk);
585 } else {
586 icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
587 len + sizeof(struct icmp6hdr));
588 }
589 rcu_read_unlock();
590out_dst_release:
591 dst_release(dst);
592out:
593 icmpv6_xmit_unlock(sk);
594out_bh_enable:
595 local_bh_enable();
596}
597
598/* Slightly more convenient version of icmp6_send.
599 */
600void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos)
601{
602 icmp6_send(skb, ICMPV6_PARAMPROB, code, pos, NULL);
603 kfree_skb(skb);
604}
605
606/* Generate icmpv6 with type/code ICMPV6_DEST_UNREACH/ICMPV6_ADDR_UNREACH
607 * if sufficient data bytes are available
608 * @nhs is the size of the tunnel header(s) :
609 * Either an IPv4 header for SIT encap
610 * an IPv4 header + GRE header for GRE encap
611 */
612int ip6_err_gen_icmpv6_unreach(struct sk_buff *skb, int nhs, int type,
613 unsigned int data_len)
614{
615 struct in6_addr temp_saddr;
616 struct rt6_info *rt;
617 struct sk_buff *skb2;
618 u32 info = 0;
619
620 if (!pskb_may_pull(skb, nhs + sizeof(struct ipv6hdr) + 8))
621 return 1;
622
623 /* RFC 4884 (partial) support for ICMP extensions */
624 if (data_len < 128 || (data_len & 7) || skb->len < data_len)
625 data_len = 0;
626
627 skb2 = data_len ? skb_copy(skb, GFP_ATOMIC) : skb_clone(skb, GFP_ATOMIC);
628
629 if (!skb2)
630 return 1;
631
632 skb_dst_drop(skb2);
633 skb_pull(skb2, nhs);
634 skb_reset_network_header(skb2);
635
636 rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr, NULL, 0,
637 skb, 0);
638
639 if (rt && rt->dst.dev)
640 skb2->dev = rt->dst.dev;
641
642 ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr, &temp_saddr);
643
644 if (data_len) {
645 /* RFC 4884 (partial) support :
646 * insert 0 padding at the end, before the extensions
647 */
648 __skb_push(skb2, nhs);
649 skb_reset_network_header(skb2);
650 memmove(skb2->data, skb2->data + nhs, data_len - nhs);
651 memset(skb2->data + data_len - nhs, 0, nhs);
652 /* RFC 4884 4.5 : Length is measured in 64-bit words,
653 * and stored in reserved[0]
654 */
655 info = (data_len/8) << 24;
656 }
657 if (type == ICMP_TIME_EXCEEDED)
658 icmp6_send(skb2, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
659 info, &temp_saddr);
660 else
661 icmp6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH,
662 info, &temp_saddr);
663 if (rt)
664 ip6_rt_put(rt);
665
666 kfree_skb(skb2);
667
668 return 0;
669}
670EXPORT_SYMBOL(ip6_err_gen_icmpv6_unreach);
671
672static void icmpv6_echo_reply(struct sk_buff *skb)
673{
674 struct net *net = dev_net(skb->dev);
675 struct sock *sk;
676 struct inet6_dev *idev;
677 struct ipv6_pinfo *np;
678 const struct in6_addr *saddr = NULL;
679 struct icmp6hdr *icmph = icmp6_hdr(skb);
680 struct icmp6hdr tmp_hdr;
681 struct flowi6 fl6;
682 struct icmpv6_msg msg;
683 struct dst_entry *dst;
684 struct ipcm6_cookie ipc6;
685 u32 mark = IP6_REPLY_MARK(net, skb->mark);
686 bool acast;
687
688 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) &&
689 net->ipv6.sysctl.icmpv6_echo_ignore_multicast)
690 return;
691
692 saddr = &ipv6_hdr(skb)->daddr;
693
694 acast = ipv6_anycast_destination(skb_dst(skb), saddr);
695 if (acast && net->ipv6.sysctl.icmpv6_echo_ignore_anycast)
696 return;
697
698 if (!ipv6_unicast_destination(skb) &&
699 !(net->ipv6.sysctl.anycast_src_echo_reply && acast))
700 saddr = NULL;
701
702 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
703 tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;
704
705 memset(&fl6, 0, sizeof(fl6));
706 if (net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_ICMPV6_ECHO_REPLIES)
707 fl6.flowlabel = ip6_flowlabel(ipv6_hdr(skb));
708
709 fl6.flowi6_proto = IPPROTO_ICMPV6;
710 fl6.daddr = ipv6_hdr(skb)->saddr;
711 if (saddr)
712 fl6.saddr = *saddr;
713 fl6.flowi6_oif = icmp6_iif(skb);
714 fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY;
715 fl6.flowi6_mark = mark;
716 fl6.flowi6_uid = sock_net_uid(net, NULL);
717 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
718
719 local_bh_disable();
720 sk = icmpv6_xmit_lock(net);
721 if (!sk)
722 goto out_bh_enable;
723 sk->sk_mark = mark;
724 np = inet6_sk(sk);
725
726 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
727 fl6.flowi6_oif = np->mcast_oif;
728 else if (!fl6.flowi6_oif)
729 fl6.flowi6_oif = np->ucast_oif;
730
731 if (ip6_dst_lookup(net, sk, &dst, &fl6))
732 goto out;
733 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
734 if (IS_ERR(dst))
735 goto out;
736
737 /* Check the ratelimit */
738 if ((!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, ICMPV6_ECHO_REPLY)) ||
739 !icmpv6_xrlim_allow(sk, ICMPV6_ECHO_REPLY, &fl6))
740 goto out_dst_release;
741
742 idev = __in6_dev_get(skb->dev);
743
744 msg.skb = skb;
745 msg.offset = 0;
746 msg.type = ICMPV6_ECHO_REPLY;
747
748 ipcm6_init_sk(&ipc6, np);
749 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
750 ipc6.tclass = ipv6_get_dsfield(ipv6_hdr(skb));
751
752 if (ip6_append_data(sk, icmpv6_getfrag, &msg,
753 skb->len + sizeof(struct icmp6hdr),
754 sizeof(struct icmp6hdr), &ipc6, &fl6,
755 (struct rt6_info *)dst, MSG_DONTWAIT)) {
756 __ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS);
757 ip6_flush_pending_frames(sk);
758 } else {
759 icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
760 skb->len + sizeof(struct icmp6hdr));
761 }
762out_dst_release:
763 dst_release(dst);
764out:
765 icmpv6_xmit_unlock(sk);
766out_bh_enable:
767 local_bh_enable();
768}
769
770void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info)
771{
772 const struct inet6_protocol *ipprot;
773 int inner_offset;
774 __be16 frag_off;
775 u8 nexthdr;
776 struct net *net = dev_net(skb->dev);
777
778 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
779 goto out;
780
781 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
782 if (ipv6_ext_hdr(nexthdr)) {
783 /* now skip over extension headers */
784 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
785 &nexthdr, &frag_off);
786 if (inner_offset < 0)
787 goto out;
788 } else {
789 inner_offset = sizeof(struct ipv6hdr);
790 }
791
792 /* Checkin header including 8 bytes of inner protocol header. */
793 if (!pskb_may_pull(skb, inner_offset+8))
794 goto out;
795
796 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
797 Without this we will not able f.e. to make source routed
798 pmtu discovery.
799 Corresponding argument (opt) to notifiers is already added.
800 --ANK (980726)
801 */
802
803 ipprot = rcu_dereference(inet6_protos[nexthdr]);
804 if (ipprot && ipprot->err_handler)
805 ipprot->err_handler(skb, NULL, type, code, inner_offset, info);
806
807 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
808 return;
809
810out:
811 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS);
812}
813
814/*
815 * Handle icmp messages
816 */
817
818static int icmpv6_rcv(struct sk_buff *skb)
819{
820 struct net *net = dev_net(skb->dev);
821 struct net_device *dev = icmp6_dev(skb);
822 struct inet6_dev *idev = __in6_dev_get(dev);
823 const struct in6_addr *saddr, *daddr;
824 struct icmp6hdr *hdr;
825 u8 type;
826 bool success = false;
827
828 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
829 struct sec_path *sp = skb_sec_path(skb);
830 int nh;
831
832 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
833 XFRM_STATE_ICMP))
834 goto drop_no_count;
835
836 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr)))
837 goto drop_no_count;
838
839 nh = skb_network_offset(skb);
840 skb_set_network_header(skb, sizeof(*hdr));
841
842 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
843 goto drop_no_count;
844
845 skb_set_network_header(skb, nh);
846 }
847
848 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INMSGS);
849
850 saddr = &ipv6_hdr(skb)->saddr;
851 daddr = &ipv6_hdr(skb)->daddr;
852
853 if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) {
854 net_dbg_ratelimited("ICMPv6 checksum failed [%pI6c > %pI6c]\n",
855 saddr, daddr);
856 goto csum_error;
857 }
858
859 if (!pskb_pull(skb, sizeof(*hdr)))
860 goto discard_it;
861
862 hdr = icmp6_hdr(skb);
863
864 type = hdr->icmp6_type;
865
866 ICMP6MSGIN_INC_STATS(dev_net(dev), idev, type);
867
868 switch (type) {
869 case ICMPV6_ECHO_REQUEST:
870 if (!net->ipv6.sysctl.icmpv6_echo_ignore_all)
871 icmpv6_echo_reply(skb);
872 break;
873
874 case ICMPV6_ECHO_REPLY:
875 success = ping_rcv(skb);
876 break;
877
878 case ICMPV6_PKT_TOOBIG:
879 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
880 standard destination cache. Seems, only "advanced"
881 destination cache will allow to solve this problem
882 --ANK (980726)
883 */
884 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
885 goto discard_it;
886 hdr = icmp6_hdr(skb);
887
888 /* to notify */
889 /* fall through */
890 case ICMPV6_DEST_UNREACH:
891 case ICMPV6_TIME_EXCEED:
892 case ICMPV6_PARAMPROB:
893 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
894 break;
895
896 case NDISC_ROUTER_SOLICITATION:
897 case NDISC_ROUTER_ADVERTISEMENT:
898 case NDISC_NEIGHBOUR_SOLICITATION:
899 case NDISC_NEIGHBOUR_ADVERTISEMENT:
900 case NDISC_REDIRECT:
901 ndisc_rcv(skb);
902 break;
903
904 case ICMPV6_MGM_QUERY:
905 igmp6_event_query(skb);
906 break;
907
908 case ICMPV6_MGM_REPORT:
909 igmp6_event_report(skb);
910 break;
911
912 case ICMPV6_MGM_REDUCTION:
913 case ICMPV6_NI_QUERY:
914 case ICMPV6_NI_REPLY:
915 case ICMPV6_MLD2_REPORT:
916 case ICMPV6_DHAAD_REQUEST:
917 case ICMPV6_DHAAD_REPLY:
918 case ICMPV6_MOBILE_PREFIX_SOL:
919 case ICMPV6_MOBILE_PREFIX_ADV:
920 break;
921
922 default:
923 /* informational */
924 if (type & ICMPV6_INFOMSG_MASK)
925 break;
926
927 net_dbg_ratelimited("icmpv6: msg of unknown type [%pI6c > %pI6c]\n",
928 saddr, daddr);
929
930 /*
931 * error of unknown type.
932 * must pass to upper level
933 */
934
935 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
936 }
937
938 /* until the v6 path can be better sorted assume failure and
939 * preserve the status quo behaviour for the rest of the paths to here
940 */
941 if (success)
942 consume_skb(skb);
943 else
944 kfree_skb(skb);
945
946 return 0;
947
948csum_error:
949 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS);
950discard_it:
951 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INERRORS);
952drop_no_count:
953 kfree_skb(skb);
954 return 0;
955}
956
957void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6,
958 u8 type,
959 const struct in6_addr *saddr,
960 const struct in6_addr *daddr,
961 int oif)
962{
963 memset(fl6, 0, sizeof(*fl6));
964 fl6->saddr = *saddr;
965 fl6->daddr = *daddr;
966 fl6->flowi6_proto = IPPROTO_ICMPV6;
967 fl6->fl6_icmp_type = type;
968 fl6->fl6_icmp_code = 0;
969 fl6->flowi6_oif = oif;
970 security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
971}
972
973static void __net_exit icmpv6_sk_exit(struct net *net)
974{
975 int i;
976
977 for_each_possible_cpu(i)
978 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv6.icmp_sk, i));
979 free_percpu(net->ipv6.icmp_sk);
980}
981
982static int __net_init icmpv6_sk_init(struct net *net)
983{
984 struct sock *sk;
985 int err, i;
986
987 net->ipv6.icmp_sk = alloc_percpu(struct sock *);
988 if (!net->ipv6.icmp_sk)
989 return -ENOMEM;
990
991 for_each_possible_cpu(i) {
992 err = inet_ctl_sock_create(&sk, PF_INET6,
993 SOCK_RAW, IPPROTO_ICMPV6, net);
994 if (err < 0) {
995 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n",
996 err);
997 goto fail;
998 }
999
1000 *per_cpu_ptr(net->ipv6.icmp_sk, i) = sk;
1001
1002 /* Enough space for 2 64K ICMP packets, including
1003 * sk_buff struct overhead.
1004 */
1005 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
1006 }
1007 return 0;
1008
1009 fail:
1010 icmpv6_sk_exit(net);
1011 return err;
1012}
1013
1014static struct pernet_operations icmpv6_sk_ops = {
1015 .init = icmpv6_sk_init,
1016 .exit = icmpv6_sk_exit,
1017};
1018
1019int __init icmpv6_init(void)
1020{
1021 int err;
1022
1023 err = register_pernet_subsys(&icmpv6_sk_ops);
1024 if (err < 0)
1025 return err;
1026
1027 err = -EAGAIN;
1028 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0)
1029 goto fail;
1030
1031 err = inet6_register_icmp_sender(icmp6_send);
1032 if (err)
1033 goto sender_reg_err;
1034 return 0;
1035
1036sender_reg_err:
1037 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
1038fail:
1039 pr_err("Failed to register ICMP6 protocol\n");
1040 unregister_pernet_subsys(&icmpv6_sk_ops);
1041 return err;
1042}
1043
1044void icmpv6_cleanup(void)
1045{
1046 inet6_unregister_icmp_sender(icmp6_send);
1047 unregister_pernet_subsys(&icmpv6_sk_ops);
1048 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
1049}
1050
1051
1052static const struct icmp6_err {
1053 int err;
1054 int fatal;
1055} tab_unreach[] = {
1056 { /* NOROUTE */
1057 .err = ENETUNREACH,
1058 .fatal = 0,
1059 },
1060 { /* ADM_PROHIBITED */
1061 .err = EACCES,
1062 .fatal = 1,
1063 },
1064 { /* Was NOT_NEIGHBOUR, now reserved */
1065 .err = EHOSTUNREACH,
1066 .fatal = 0,
1067 },
1068 { /* ADDR_UNREACH */
1069 .err = EHOSTUNREACH,
1070 .fatal = 0,
1071 },
1072 { /* PORT_UNREACH */
1073 .err = ECONNREFUSED,
1074 .fatal = 1,
1075 },
1076 { /* POLICY_FAIL */
1077 .err = EACCES,
1078 .fatal = 1,
1079 },
1080 { /* REJECT_ROUTE */
1081 .err = EACCES,
1082 .fatal = 1,
1083 },
1084};
1085
1086int icmpv6_err_convert(u8 type, u8 code, int *err)
1087{
1088 int fatal = 0;
1089
1090 *err = EPROTO;
1091
1092 switch (type) {
1093 case ICMPV6_DEST_UNREACH:
1094 fatal = 1;
1095 if (code < ARRAY_SIZE(tab_unreach)) {
1096 *err = tab_unreach[code].err;
1097 fatal = tab_unreach[code].fatal;
1098 }
1099 break;
1100
1101 case ICMPV6_PKT_TOOBIG:
1102 *err = EMSGSIZE;
1103 break;
1104
1105 case ICMPV6_PARAMPROB:
1106 *err = EPROTO;
1107 fatal = 1;
1108 break;
1109
1110 case ICMPV6_TIME_EXCEED:
1111 *err = EHOSTUNREACH;
1112 break;
1113 }
1114
1115 return fatal;
1116}
1117EXPORT_SYMBOL(icmpv6_err_convert);
1118
1119#ifdef CONFIG_SYSCTL
1120static struct ctl_table ipv6_icmp_table_template[] = {
1121 {
1122 .procname = "ratelimit",
1123 .data = &init_net.ipv6.sysctl.icmpv6_time,
1124 .maxlen = sizeof(int),
1125 .mode = 0644,
1126 .proc_handler = proc_dointvec_ms_jiffies,
1127 },
1128 {
1129 .procname = "echo_ignore_all",
1130 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_all,
1131 .maxlen = sizeof(int),
1132 .mode = 0644,
1133 .proc_handler = proc_dointvec,
1134 },
1135 {
1136 .procname = "echo_ignore_multicast",
1137 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_multicast,
1138 .maxlen = sizeof(int),
1139 .mode = 0644,
1140 .proc_handler = proc_dointvec,
1141 },
1142 {
1143 .procname = "echo_ignore_anycast",
1144 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_anycast,
1145 .maxlen = sizeof(int),
1146 .mode = 0644,
1147 .proc_handler = proc_dointvec,
1148 },
1149 {
1150 .procname = "ratemask",
1151 .data = &init_net.ipv6.sysctl.icmpv6_ratemask_ptr,
1152 .maxlen = ICMPV6_MSG_MAX + 1,
1153 .mode = 0644,
1154 .proc_handler = proc_do_large_bitmap,
1155 },
1156 { },
1157};
1158
1159struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
1160{
1161 struct ctl_table *table;
1162
1163 table = kmemdup(ipv6_icmp_table_template,
1164 sizeof(ipv6_icmp_table_template),
1165 GFP_KERNEL);
1166
1167 if (table) {
1168 table[0].data = &net->ipv6.sysctl.icmpv6_time;
1169 table[1].data = &net->ipv6.sysctl.icmpv6_echo_ignore_all;
1170 table[2].data = &net->ipv6.sysctl.icmpv6_echo_ignore_multicast;
1171 table[3].data = &net->ipv6.sysctl.icmpv6_echo_ignore_anycast;
1172 table[4].data = &net->ipv6.sysctl.icmpv6_ratemask_ptr;
1173 }
1174 return table;
1175}
1176#endif