Loading...
1/*
2 * Internet Control Message Protocol (ICMPv6)
3 * Linux INET6 implementation
4 *
5 * Authors:
6 * Pedro Roque <roque@di.fc.ul.pt>
7 *
8 * Based on net/ipv4/icmp.c
9 *
10 * RFC 1885
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
16 */
17
18/*
19 * Changes:
20 *
21 * Andi Kleen : exception handling
22 * Andi Kleen add rate limits. never reply to a icmp.
23 * add more length checks and other fixes.
24 * yoshfuji : ensure to sent parameter problem for
25 * fragments.
26 * YOSHIFUJI Hideaki @USAGI: added sysctl for icmp rate limit.
27 * Randy Dunlap and
28 * YOSHIFUJI Hideaki @USAGI: Per-interface statistics support
29 * Kazunori MIYAZAWA @USAGI: change output process to use ip6_append_data
30 */
31
32#define pr_fmt(fmt) "IPv6: " fmt
33
34#include <linux/module.h>
35#include <linux/errno.h>
36#include <linux/types.h>
37#include <linux/socket.h>
38#include <linux/in.h>
39#include <linux/kernel.h>
40#include <linux/sockios.h>
41#include <linux/net.h>
42#include <linux/skbuff.h>
43#include <linux/init.h>
44#include <linux/netfilter.h>
45#include <linux/slab.h>
46
47#ifdef CONFIG_SYSCTL
48#include <linux/sysctl.h>
49#endif
50
51#include <linux/inet.h>
52#include <linux/netdevice.h>
53#include <linux/icmpv6.h>
54
55#include <net/ip.h>
56#include <net/sock.h>
57
58#include <net/ipv6.h>
59#include <net/ip6_checksum.h>
60#include <net/ping.h>
61#include <net/protocol.h>
62#include <net/raw.h>
63#include <net/rawv6.h>
64#include <net/transp_v6.h>
65#include <net/ip6_route.h>
66#include <net/addrconf.h>
67#include <net/icmp.h>
68#include <net/xfrm.h>
69#include <net/inet_common.h>
70#include <net/dsfield.h>
71
72#include <asm/uaccess.h>
73
74/*
75 * The ICMP socket(s). This is the most convenient way to flow control
76 * our ICMP output as well as maintain a clean interface throughout
77 * all layers. All Socketless IP sends will soon be gone.
78 *
79 * On SMP we have one ICMP socket per-cpu.
80 */
81static inline struct sock *icmpv6_sk(struct net *net)
82{
83 return net->ipv6.icmp_sk[smp_processor_id()];
84}
85
86static void icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
87 u8 type, u8 code, int offset, __be32 info)
88{
89 /* icmpv6_notify checks 8 bytes can be pulled, icmp6hdr is 8 bytes */
90 struct icmp6hdr *icmp6 = (struct icmp6hdr *) (skb->data + offset);
91 struct net *net = dev_net(skb->dev);
92
93 if (type == ICMPV6_PKT_TOOBIG)
94 ip6_update_pmtu(skb, net, info, 0, 0);
95 else if (type == NDISC_REDIRECT)
96 ip6_redirect(skb, net, skb->dev->ifindex, 0);
97
98 if (!(type & ICMPV6_INFOMSG_MASK))
99 if (icmp6->icmp6_type == ICMPV6_ECHO_REQUEST)
100 ping_err(skb, offset, info);
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
111static __inline__ struct sock *icmpv6_xmit_lock(struct net *net)
112{
113 struct sock *sk;
114
115 local_bh_disable();
116
117 sk = icmpv6_sk(net);
118 if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
119 /* This can happen if the output path (f.e. SIT or
120 * ip6ip6 tunnel) signals dst_link_failure() for an
121 * outgoing ICMP6 packet.
122 */
123 local_bh_enable();
124 return NULL;
125 }
126 return sk;
127}
128
129static __inline__ void icmpv6_xmit_unlock(struct sock *sk)
130{
131 spin_unlock_bh(&sk->sk_lock.slock);
132}
133
134/*
135 * Figure out, may we reply to this packet with icmp error.
136 *
137 * We do not reply, if:
138 * - it was icmp error message.
139 * - it is truncated, so that it is known, that protocol is ICMPV6
140 * (i.e. in the middle of some exthdr)
141 *
142 * --ANK (980726)
143 */
144
145static bool is_ineligible(const struct sk_buff *skb)
146{
147 int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
148 int len = skb->len - ptr;
149 __u8 nexthdr = ipv6_hdr(skb)->nexthdr;
150 __be16 frag_off;
151
152 if (len < 0)
153 return true;
154
155 ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off);
156 if (ptr < 0)
157 return false;
158 if (nexthdr == IPPROTO_ICMPV6) {
159 u8 _type, *tp;
160 tp = skb_header_pointer(skb,
161 ptr+offsetof(struct icmp6hdr, icmp6_type),
162 sizeof(_type), &_type);
163 if (tp == NULL ||
164 !(*tp & ICMPV6_INFOMSG_MASK))
165 return true;
166 }
167 return false;
168}
169
170/*
171 * Check the ICMP output rate limit
172 */
173static inline bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
174 struct flowi6 *fl6)
175{
176 struct dst_entry *dst;
177 struct net *net = sock_net(sk);
178 bool res = false;
179
180 /* Informational messages are not limited. */
181 if (type & ICMPV6_INFOMSG_MASK)
182 return true;
183
184 /* Do not limit pmtu discovery, it would break it. */
185 if (type == ICMPV6_PKT_TOOBIG)
186 return true;
187
188 /*
189 * Look up the output route.
190 * XXX: perhaps the expire for routing entries cloned by
191 * this lookup should be more aggressive (not longer than timeout).
192 */
193 dst = ip6_route_output(net, sk, fl6);
194 if (dst->error) {
195 IP6_INC_STATS(net, ip6_dst_idev(dst),
196 IPSTATS_MIB_OUTNOROUTES);
197 } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
198 res = true;
199 } else {
200 struct rt6_info *rt = (struct rt6_info *)dst;
201 int tmo = net->ipv6.sysctl.icmpv6_time;
202 struct inet_peer *peer;
203
204 /* Give more bandwidth to wider prefixes. */
205 if (rt->rt6i_dst.plen < 128)
206 tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
207
208 peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
209 res = inet_peer_xrlim_allow(peer, tmo);
210 if (peer)
211 inet_putpeer(peer);
212 }
213 dst_release(dst);
214 return res;
215}
216
217/*
218 * an inline helper for the "simple" if statement below
219 * checks if parameter problem report is caused by an
220 * unrecognized IPv6 option that has the Option Type
221 * highest-order two bits set to 10
222 */
223
224static bool opt_unrec(struct sk_buff *skb, __u32 offset)
225{
226 u8 _optval, *op;
227
228 offset += skb_network_offset(skb);
229 op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
230 if (op == NULL)
231 return true;
232 return (*op & 0xC0) == 0x80;
233}
234
235int icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6,
236 struct icmp6hdr *thdr, int len)
237{
238 struct sk_buff *skb;
239 struct icmp6hdr *icmp6h;
240 int err = 0;
241
242 if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
243 goto out;
244
245 icmp6h = icmp6_hdr(skb);
246 memcpy(icmp6h, thdr, sizeof(struct icmp6hdr));
247 icmp6h->icmp6_cksum = 0;
248
249 if (skb_queue_len(&sk->sk_write_queue) == 1) {
250 skb->csum = csum_partial(icmp6h,
251 sizeof(struct icmp6hdr), skb->csum);
252 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
253 &fl6->daddr,
254 len, fl6->flowi6_proto,
255 skb->csum);
256 } else {
257 __wsum tmp_csum = 0;
258
259 skb_queue_walk(&sk->sk_write_queue, skb) {
260 tmp_csum = csum_add(tmp_csum, skb->csum);
261 }
262
263 tmp_csum = csum_partial(icmp6h,
264 sizeof(struct icmp6hdr), tmp_csum);
265 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
266 &fl6->daddr,
267 len, fl6->flowi6_proto,
268 tmp_csum);
269 }
270 ip6_push_pending_frames(sk);
271out:
272 return err;
273}
274
275struct icmpv6_msg {
276 struct sk_buff *skb;
277 int offset;
278 uint8_t type;
279};
280
281static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
282{
283 struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
284 struct sk_buff *org_skb = msg->skb;
285 __wsum csum = 0;
286
287 csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
288 to, len, csum);
289 skb->csum = csum_block_add(skb->csum, csum, odd);
290 if (!(msg->type & ICMPV6_INFOMSG_MASK))
291 nf_ct_attach(skb, org_skb);
292 return 0;
293}
294
295#if IS_ENABLED(CONFIG_IPV6_MIP6)
296static void mip6_addr_swap(struct sk_buff *skb)
297{
298 struct ipv6hdr *iph = ipv6_hdr(skb);
299 struct inet6_skb_parm *opt = IP6CB(skb);
300 struct ipv6_destopt_hao *hao;
301 struct in6_addr tmp;
302 int off;
303
304 if (opt->dsthao) {
305 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
306 if (likely(off >= 0)) {
307 hao = (struct ipv6_destopt_hao *)
308 (skb_network_header(skb) + off);
309 tmp = iph->saddr;
310 iph->saddr = hao->addr;
311 hao->addr = tmp;
312 }
313 }
314}
315#else
316static inline void mip6_addr_swap(struct sk_buff *skb) {}
317#endif
318
319static struct dst_entry *icmpv6_route_lookup(struct net *net,
320 struct sk_buff *skb,
321 struct sock *sk,
322 struct flowi6 *fl6)
323{
324 struct dst_entry *dst, *dst2;
325 struct flowi6 fl2;
326 int err;
327
328 err = ip6_dst_lookup(sk, &dst, fl6);
329 if (err)
330 return ERR_PTR(err);
331
332 /*
333 * We won't send icmp if the destination is known
334 * anycast.
335 */
336 if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) {
337 LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: acast source\n");
338 dst_release(dst);
339 return ERR_PTR(-EINVAL);
340 }
341
342 /* No need to clone since we're just using its address. */
343 dst2 = dst;
344
345 dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0);
346 if (!IS_ERR(dst)) {
347 if (dst != dst2)
348 return dst;
349 } else {
350 if (PTR_ERR(dst) == -EPERM)
351 dst = NULL;
352 else
353 return dst;
354 }
355
356 err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6);
357 if (err)
358 goto relookup_failed;
359
360 err = ip6_dst_lookup(sk, &dst2, &fl2);
361 if (err)
362 goto relookup_failed;
363
364 dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP);
365 if (!IS_ERR(dst2)) {
366 dst_release(dst);
367 dst = dst2;
368 } else {
369 err = PTR_ERR(dst2);
370 if (err == -EPERM) {
371 dst_release(dst);
372 return dst2;
373 } else
374 goto relookup_failed;
375 }
376
377relookup_failed:
378 if (dst)
379 return dst;
380 return ERR_PTR(err);
381}
382
383/*
384 * Send an ICMP message in response to a packet in error
385 */
386static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
387{
388 struct net *net = dev_net(skb->dev);
389 struct inet6_dev *idev = NULL;
390 struct ipv6hdr *hdr = ipv6_hdr(skb);
391 struct sock *sk;
392 struct ipv6_pinfo *np;
393 const struct in6_addr *saddr = NULL;
394 struct dst_entry *dst;
395 struct icmp6hdr tmp_hdr;
396 struct flowi6 fl6;
397 struct icmpv6_msg msg;
398 int iif = 0;
399 int addr_type = 0;
400 int len;
401 int hlimit;
402 int err = 0;
403
404 if ((u8 *)hdr < skb->head ||
405 (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb))
406 return;
407
408 /*
409 * Make sure we respect the rules
410 * i.e. RFC 1885 2.4(e)
411 * Rule (e.1) is enforced by not using icmp6_send
412 * in any code that processes icmp errors.
413 */
414 addr_type = ipv6_addr_type(&hdr->daddr);
415
416 if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0) ||
417 ipv6_chk_acast_addr_src(net, skb->dev, &hdr->daddr))
418 saddr = &hdr->daddr;
419
420 /*
421 * Dest addr check
422 */
423
424 if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) {
425 if (type != ICMPV6_PKT_TOOBIG &&
426 !(type == ICMPV6_PARAMPROB &&
427 code == ICMPV6_UNK_OPTION &&
428 (opt_unrec(skb, info))))
429 return;
430
431 saddr = NULL;
432 }
433
434 addr_type = ipv6_addr_type(&hdr->saddr);
435
436 /*
437 * Source addr check
438 */
439
440 if (__ipv6_addr_needs_scope_id(addr_type))
441 iif = skb->dev->ifindex;
442
443 /*
444 * Must not send error if the source does not uniquely
445 * identify a single node (RFC2463 Section 2.4).
446 * We check unspecified / multicast addresses here,
447 * and anycast addresses will be checked later.
448 */
449 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
450 LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: addr_any/mcast source\n");
451 return;
452 }
453
454 /*
455 * Never answer to a ICMP packet.
456 */
457 if (is_ineligible(skb)) {
458 LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: no reply to icmp error\n");
459 return;
460 }
461
462 mip6_addr_swap(skb);
463
464 memset(&fl6, 0, sizeof(fl6));
465 fl6.flowi6_proto = IPPROTO_ICMPV6;
466 fl6.daddr = hdr->saddr;
467 if (saddr)
468 fl6.saddr = *saddr;
469 fl6.flowi6_oif = iif;
470 fl6.fl6_icmp_type = type;
471 fl6.fl6_icmp_code = code;
472 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
473
474 sk = icmpv6_xmit_lock(net);
475 if (sk == NULL)
476 return;
477 np = inet6_sk(sk);
478
479 if (!icmpv6_xrlim_allow(sk, type, &fl6))
480 goto out;
481
482 tmp_hdr.icmp6_type = type;
483 tmp_hdr.icmp6_code = code;
484 tmp_hdr.icmp6_cksum = 0;
485 tmp_hdr.icmp6_pointer = htonl(info);
486
487 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
488 fl6.flowi6_oif = np->mcast_oif;
489 else if (!fl6.flowi6_oif)
490 fl6.flowi6_oif = np->ucast_oif;
491
492 dst = icmpv6_route_lookup(net, skb, sk, &fl6);
493 if (IS_ERR(dst))
494 goto out;
495
496 if (ipv6_addr_is_multicast(&fl6.daddr))
497 hlimit = np->mcast_hops;
498 else
499 hlimit = np->hop_limit;
500 if (hlimit < 0)
501 hlimit = ip6_dst_hoplimit(dst);
502
503 msg.skb = skb;
504 msg.offset = skb_network_offset(skb);
505 msg.type = type;
506
507 len = skb->len - msg.offset;
508 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) -sizeof(struct icmp6hdr));
509 if (len < 0) {
510 LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n");
511 goto out_dst_release;
512 }
513
514 rcu_read_lock();
515 idev = __in6_dev_get(skb->dev);
516
517 err = ip6_append_data(sk, icmpv6_getfrag, &msg,
518 len + sizeof(struct icmp6hdr),
519 sizeof(struct icmp6hdr), hlimit,
520 np->tclass, NULL, &fl6, (struct rt6_info *)dst,
521 MSG_DONTWAIT, np->dontfrag);
522 if (err) {
523 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS);
524 ip6_flush_pending_frames(sk);
525 } else {
526 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
527 len + sizeof(struct icmp6hdr));
528 }
529 rcu_read_unlock();
530out_dst_release:
531 dst_release(dst);
532out:
533 icmpv6_xmit_unlock(sk);
534}
535
536/* Slightly more convenient version of icmp6_send.
537 */
538void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos)
539{
540 icmp6_send(skb, ICMPV6_PARAMPROB, code, pos);
541 kfree_skb(skb);
542}
543
544static void icmpv6_echo_reply(struct sk_buff *skb)
545{
546 struct net *net = dev_net(skb->dev);
547 struct sock *sk;
548 struct inet6_dev *idev;
549 struct ipv6_pinfo *np;
550 const struct in6_addr *saddr = NULL;
551 struct icmp6hdr *icmph = icmp6_hdr(skb);
552 struct icmp6hdr tmp_hdr;
553 struct flowi6 fl6;
554 struct icmpv6_msg msg;
555 struct dst_entry *dst;
556 int err = 0;
557 int hlimit;
558 u8 tclass;
559
560 saddr = &ipv6_hdr(skb)->daddr;
561
562 if (!ipv6_unicast_destination(skb) &&
563 !(net->ipv6.sysctl.anycast_src_echo_reply &&
564 ipv6_anycast_destination(skb)))
565 saddr = NULL;
566
567 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
568 tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;
569
570 memset(&fl6, 0, sizeof(fl6));
571 fl6.flowi6_proto = IPPROTO_ICMPV6;
572 fl6.daddr = ipv6_hdr(skb)->saddr;
573 if (saddr)
574 fl6.saddr = *saddr;
575 fl6.flowi6_oif = skb->dev->ifindex;
576 fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY;
577 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
578
579 sk = icmpv6_xmit_lock(net);
580 if (sk == NULL)
581 return;
582 np = inet6_sk(sk);
583
584 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
585 fl6.flowi6_oif = np->mcast_oif;
586 else if (!fl6.flowi6_oif)
587 fl6.flowi6_oif = np->ucast_oif;
588
589 err = ip6_dst_lookup(sk, &dst, &fl6);
590 if (err)
591 goto out;
592 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
593 if (IS_ERR(dst))
594 goto out;
595
596 if (ipv6_addr_is_multicast(&fl6.daddr))
597 hlimit = np->mcast_hops;
598 else
599 hlimit = np->hop_limit;
600 if (hlimit < 0)
601 hlimit = ip6_dst_hoplimit(dst);
602
603 idev = __in6_dev_get(skb->dev);
604
605 msg.skb = skb;
606 msg.offset = 0;
607 msg.type = ICMPV6_ECHO_REPLY;
608
609 tclass = ipv6_get_dsfield(ipv6_hdr(skb));
610 err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr),
611 sizeof(struct icmp6hdr), hlimit, tclass, NULL, &fl6,
612 (struct rt6_info *)dst, MSG_DONTWAIT,
613 np->dontfrag);
614
615 if (err) {
616 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS);
617 ip6_flush_pending_frames(sk);
618 } else {
619 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
620 skb->len + sizeof(struct icmp6hdr));
621 }
622 dst_release(dst);
623out:
624 icmpv6_xmit_unlock(sk);
625}
626
627void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info)
628{
629 const struct inet6_protocol *ipprot;
630 int inner_offset;
631 __be16 frag_off;
632 u8 nexthdr;
633
634 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
635 return;
636
637 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
638 if (ipv6_ext_hdr(nexthdr)) {
639 /* now skip over extension headers */
640 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
641 &nexthdr, &frag_off);
642 if (inner_offset<0)
643 return;
644 } else {
645 inner_offset = sizeof(struct ipv6hdr);
646 }
647
648 /* Checkin header including 8 bytes of inner protocol header. */
649 if (!pskb_may_pull(skb, inner_offset+8))
650 return;
651
652 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
653 Without this we will not able f.e. to make source routed
654 pmtu discovery.
655 Corresponding argument (opt) to notifiers is already added.
656 --ANK (980726)
657 */
658
659 rcu_read_lock();
660 ipprot = rcu_dereference(inet6_protos[nexthdr]);
661 if (ipprot && ipprot->err_handler)
662 ipprot->err_handler(skb, NULL, type, code, inner_offset, info);
663 rcu_read_unlock();
664
665 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
666}
667
668/*
669 * Handle icmp messages
670 */
671
672static int icmpv6_rcv(struct sk_buff *skb)
673{
674 struct net_device *dev = skb->dev;
675 struct inet6_dev *idev = __in6_dev_get(dev);
676 const struct in6_addr *saddr, *daddr;
677 struct icmp6hdr *hdr;
678 u8 type;
679
680 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
681 struct sec_path *sp = skb_sec_path(skb);
682 int nh;
683
684 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
685 XFRM_STATE_ICMP))
686 goto drop_no_count;
687
688 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr)))
689 goto drop_no_count;
690
691 nh = skb_network_offset(skb);
692 skb_set_network_header(skb, sizeof(*hdr));
693
694 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
695 goto drop_no_count;
696
697 skb_set_network_header(skb, nh);
698 }
699
700 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INMSGS);
701
702 saddr = &ipv6_hdr(skb)->saddr;
703 daddr = &ipv6_hdr(skb)->daddr;
704
705 /* Perform checksum. */
706 switch (skb->ip_summed) {
707 case CHECKSUM_COMPLETE:
708 if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6,
709 skb->csum))
710 break;
711 /* fall through */
712 case CHECKSUM_NONE:
713 skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len,
714 IPPROTO_ICMPV6, 0));
715 if (__skb_checksum_complete(skb)) {
716 LIMIT_NETDEBUG(KERN_DEBUG
717 "ICMPv6 checksum failed [%pI6c > %pI6c]\n",
718 saddr, daddr);
719 goto csum_error;
720 }
721 }
722
723 if (!pskb_pull(skb, sizeof(*hdr)))
724 goto discard_it;
725
726 hdr = icmp6_hdr(skb);
727
728 type = hdr->icmp6_type;
729
730 ICMP6MSGIN_INC_STATS_BH(dev_net(dev), idev, type);
731
732 switch (type) {
733 case ICMPV6_ECHO_REQUEST:
734 icmpv6_echo_reply(skb);
735 break;
736
737 case ICMPV6_ECHO_REPLY:
738 ping_rcv(skb);
739 break;
740
741 case ICMPV6_PKT_TOOBIG:
742 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
743 standard destination cache. Seems, only "advanced"
744 destination cache will allow to solve this problem
745 --ANK (980726)
746 */
747 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
748 goto discard_it;
749 hdr = icmp6_hdr(skb);
750
751 /*
752 * Drop through to notify
753 */
754
755 case ICMPV6_DEST_UNREACH:
756 case ICMPV6_TIME_EXCEED:
757 case ICMPV6_PARAMPROB:
758 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
759 break;
760
761 case NDISC_ROUTER_SOLICITATION:
762 case NDISC_ROUTER_ADVERTISEMENT:
763 case NDISC_NEIGHBOUR_SOLICITATION:
764 case NDISC_NEIGHBOUR_ADVERTISEMENT:
765 case NDISC_REDIRECT:
766 ndisc_rcv(skb);
767 break;
768
769 case ICMPV6_MGM_QUERY:
770 igmp6_event_query(skb);
771 break;
772
773 case ICMPV6_MGM_REPORT:
774 igmp6_event_report(skb);
775 break;
776
777 case ICMPV6_MGM_REDUCTION:
778 case ICMPV6_NI_QUERY:
779 case ICMPV6_NI_REPLY:
780 case ICMPV6_MLD2_REPORT:
781 case ICMPV6_DHAAD_REQUEST:
782 case ICMPV6_DHAAD_REPLY:
783 case ICMPV6_MOBILE_PREFIX_SOL:
784 case ICMPV6_MOBILE_PREFIX_ADV:
785 break;
786
787 default:
788 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n");
789
790 /* informational */
791 if (type & ICMPV6_INFOMSG_MASK)
792 break;
793
794 /*
795 * error of unknown type.
796 * must pass to upper level
797 */
798
799 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
800 }
801
802 kfree_skb(skb);
803 return 0;
804
805csum_error:
806 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS);
807discard_it:
808 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INERRORS);
809drop_no_count:
810 kfree_skb(skb);
811 return 0;
812}
813
814void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6,
815 u8 type,
816 const struct in6_addr *saddr,
817 const struct in6_addr *daddr,
818 int oif)
819{
820 memset(fl6, 0, sizeof(*fl6));
821 fl6->saddr = *saddr;
822 fl6->daddr = *daddr;
823 fl6->flowi6_proto = IPPROTO_ICMPV6;
824 fl6->fl6_icmp_type = type;
825 fl6->fl6_icmp_code = 0;
826 fl6->flowi6_oif = oif;
827 security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
828}
829
830/*
831 * Special lock-class for __icmpv6_sk:
832 */
833static struct lock_class_key icmpv6_socket_sk_dst_lock_key;
834
835static int __net_init icmpv6_sk_init(struct net *net)
836{
837 struct sock *sk;
838 int err, i, j;
839
840 net->ipv6.icmp_sk =
841 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL);
842 if (net->ipv6.icmp_sk == NULL)
843 return -ENOMEM;
844
845 for_each_possible_cpu(i) {
846 err = inet_ctl_sock_create(&sk, PF_INET6,
847 SOCK_RAW, IPPROTO_ICMPV6, net);
848 if (err < 0) {
849 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n",
850 err);
851 goto fail;
852 }
853
854 net->ipv6.icmp_sk[i] = sk;
855
856 /*
857 * Split off their lock-class, because sk->sk_dst_lock
858 * gets used from softirqs, which is safe for
859 * __icmpv6_sk (because those never get directly used
860 * via userspace syscalls), but unsafe for normal sockets.
861 */
862 lockdep_set_class(&sk->sk_dst_lock,
863 &icmpv6_socket_sk_dst_lock_key);
864
865 /* Enough space for 2 64K ICMP packets, including
866 * sk_buff struct overhead.
867 */
868 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
869 }
870 return 0;
871
872 fail:
873 for (j = 0; j < i; j++)
874 inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]);
875 kfree(net->ipv6.icmp_sk);
876 return err;
877}
878
879static void __net_exit icmpv6_sk_exit(struct net *net)
880{
881 int i;
882
883 for_each_possible_cpu(i) {
884 inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]);
885 }
886 kfree(net->ipv6.icmp_sk);
887}
888
889static struct pernet_operations icmpv6_sk_ops = {
890 .init = icmpv6_sk_init,
891 .exit = icmpv6_sk_exit,
892};
893
894int __init icmpv6_init(void)
895{
896 int err;
897
898 err = register_pernet_subsys(&icmpv6_sk_ops);
899 if (err < 0)
900 return err;
901
902 err = -EAGAIN;
903 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0)
904 goto fail;
905
906 err = inet6_register_icmp_sender(icmp6_send);
907 if (err)
908 goto sender_reg_err;
909 return 0;
910
911sender_reg_err:
912 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
913fail:
914 pr_err("Failed to register ICMP6 protocol\n");
915 unregister_pernet_subsys(&icmpv6_sk_ops);
916 return err;
917}
918
919void icmpv6_cleanup(void)
920{
921 inet6_unregister_icmp_sender(icmp6_send);
922 unregister_pernet_subsys(&icmpv6_sk_ops);
923 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
924}
925
926
927static const struct icmp6_err {
928 int err;
929 int fatal;
930} tab_unreach[] = {
931 { /* NOROUTE */
932 .err = ENETUNREACH,
933 .fatal = 0,
934 },
935 { /* ADM_PROHIBITED */
936 .err = EACCES,
937 .fatal = 1,
938 },
939 { /* Was NOT_NEIGHBOUR, now reserved */
940 .err = EHOSTUNREACH,
941 .fatal = 0,
942 },
943 { /* ADDR_UNREACH */
944 .err = EHOSTUNREACH,
945 .fatal = 0,
946 },
947 { /* PORT_UNREACH */
948 .err = ECONNREFUSED,
949 .fatal = 1,
950 },
951 { /* POLICY_FAIL */
952 .err = EACCES,
953 .fatal = 1,
954 },
955 { /* REJECT_ROUTE */
956 .err = EACCES,
957 .fatal = 1,
958 },
959};
960
961int icmpv6_err_convert(u8 type, u8 code, int *err)
962{
963 int fatal = 0;
964
965 *err = EPROTO;
966
967 switch (type) {
968 case ICMPV6_DEST_UNREACH:
969 fatal = 1;
970 if (code < ARRAY_SIZE(tab_unreach)) {
971 *err = tab_unreach[code].err;
972 fatal = tab_unreach[code].fatal;
973 }
974 break;
975
976 case ICMPV6_PKT_TOOBIG:
977 *err = EMSGSIZE;
978 break;
979
980 case ICMPV6_PARAMPROB:
981 *err = EPROTO;
982 fatal = 1;
983 break;
984
985 case ICMPV6_TIME_EXCEED:
986 *err = EHOSTUNREACH;
987 break;
988 }
989
990 return fatal;
991}
992EXPORT_SYMBOL(icmpv6_err_convert);
993
994#ifdef CONFIG_SYSCTL
995static struct ctl_table ipv6_icmp_table_template[] = {
996 {
997 .procname = "ratelimit",
998 .data = &init_net.ipv6.sysctl.icmpv6_time,
999 .maxlen = sizeof(int),
1000 .mode = 0644,
1001 .proc_handler = proc_dointvec_ms_jiffies,
1002 },
1003 { },
1004};
1005
1006struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
1007{
1008 struct ctl_table *table;
1009
1010 table = kmemdup(ipv6_icmp_table_template,
1011 sizeof(ipv6_icmp_table_template),
1012 GFP_KERNEL);
1013
1014 if (table)
1015 table[0].data = &net->ipv6.sysctl.icmpv6_time;
1016
1017 return table;
1018}
1019#endif
1020
1/*
2 * Internet Control Message Protocol (ICMPv6)
3 * Linux INET6 implementation
4 *
5 * Authors:
6 * Pedro Roque <roque@di.fc.ul.pt>
7 *
8 * Based on net/ipv4/icmp.c
9 *
10 * RFC 1885
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
16 */
17
18/*
19 * Changes:
20 *
21 * Andi Kleen : exception handling
22 * Andi Kleen add rate limits. never reply to a icmp.
23 * add more length checks and other fixes.
24 * yoshfuji : ensure to sent parameter problem for
25 * fragments.
26 * YOSHIFUJI Hideaki @USAGI: added sysctl for icmp rate limit.
27 * Randy Dunlap and
28 * YOSHIFUJI Hideaki @USAGI: Per-interface statistics support
29 * Kazunori MIYAZAWA @USAGI: change output process to use ip6_append_data
30 */
31
32#define pr_fmt(fmt) "IPv6: " fmt
33
34#include <linux/module.h>
35#include <linux/errno.h>
36#include <linux/types.h>
37#include <linux/socket.h>
38#include <linux/in.h>
39#include <linux/kernel.h>
40#include <linux/sockios.h>
41#include <linux/net.h>
42#include <linux/skbuff.h>
43#include <linux/init.h>
44#include <linux/netfilter.h>
45#include <linux/slab.h>
46
47#ifdef CONFIG_SYSCTL
48#include <linux/sysctl.h>
49#endif
50
51#include <linux/inet.h>
52#include <linux/netdevice.h>
53#include <linux/icmpv6.h>
54
55#include <net/ip.h>
56#include <net/sock.h>
57
58#include <net/ipv6.h>
59#include <net/ip6_checksum.h>
60#include <net/protocol.h>
61#include <net/raw.h>
62#include <net/rawv6.h>
63#include <net/transp_v6.h>
64#include <net/ip6_route.h>
65#include <net/addrconf.h>
66#include <net/icmp.h>
67#include <net/xfrm.h>
68#include <net/inet_common.h>
69
70#include <asm/uaccess.h>
71
72/*
73 * The ICMP socket(s). This is the most convenient way to flow control
74 * our ICMP output as well as maintain a clean interface throughout
75 * all layers. All Socketless IP sends will soon be gone.
76 *
77 * On SMP we have one ICMP socket per-cpu.
78 */
79static inline struct sock *icmpv6_sk(struct net *net)
80{
81 return net->ipv6.icmp_sk[smp_processor_id()];
82}
83
84static int icmpv6_rcv(struct sk_buff *skb);
85
86static const struct inet6_protocol icmpv6_protocol = {
87 .handler = icmpv6_rcv,
88 .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
89};
90
91static __inline__ struct sock *icmpv6_xmit_lock(struct net *net)
92{
93 struct sock *sk;
94
95 local_bh_disable();
96
97 sk = icmpv6_sk(net);
98 if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
99 /* This can happen if the output path (f.e. SIT or
100 * ip6ip6 tunnel) signals dst_link_failure() for an
101 * outgoing ICMP6 packet.
102 */
103 local_bh_enable();
104 return NULL;
105 }
106 return sk;
107}
108
109static __inline__ void icmpv6_xmit_unlock(struct sock *sk)
110{
111 spin_unlock_bh(&sk->sk_lock.slock);
112}
113
114/*
115 * Slightly more convenient version of icmpv6_send.
116 */
117void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos)
118{
119 icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos);
120 kfree_skb(skb);
121}
122
123/*
124 * Figure out, may we reply to this packet with icmp error.
125 *
126 * We do not reply, if:
127 * - it was icmp error message.
128 * - it is truncated, so that it is known, that protocol is ICMPV6
129 * (i.e. in the middle of some exthdr)
130 *
131 * --ANK (980726)
132 */
133
134static bool is_ineligible(const struct sk_buff *skb)
135{
136 int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
137 int len = skb->len - ptr;
138 __u8 nexthdr = ipv6_hdr(skb)->nexthdr;
139 __be16 frag_off;
140
141 if (len < 0)
142 return true;
143
144 ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off);
145 if (ptr < 0)
146 return false;
147 if (nexthdr == IPPROTO_ICMPV6) {
148 u8 _type, *tp;
149 tp = skb_header_pointer(skb,
150 ptr+offsetof(struct icmp6hdr, icmp6_type),
151 sizeof(_type), &_type);
152 if (tp == NULL ||
153 !(*tp & ICMPV6_INFOMSG_MASK))
154 return true;
155 }
156 return false;
157}
158
159/*
160 * Check the ICMP output rate limit
161 */
162static inline bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
163 struct flowi6 *fl6)
164{
165 struct dst_entry *dst;
166 struct net *net = sock_net(sk);
167 bool res = false;
168
169 /* Informational messages are not limited. */
170 if (type & ICMPV6_INFOMSG_MASK)
171 return true;
172
173 /* Do not limit pmtu discovery, it would break it. */
174 if (type == ICMPV6_PKT_TOOBIG)
175 return true;
176
177 /*
178 * Look up the output route.
179 * XXX: perhaps the expire for routing entries cloned by
180 * this lookup should be more aggressive (not longer than timeout).
181 */
182 dst = ip6_route_output(net, sk, fl6);
183 if (dst->error) {
184 IP6_INC_STATS(net, ip6_dst_idev(dst),
185 IPSTATS_MIB_OUTNOROUTES);
186 } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
187 res = true;
188 } else {
189 struct rt6_info *rt = (struct rt6_info *)dst;
190 int tmo = net->ipv6.sysctl.icmpv6_time;
191
192 /* Give more bandwidth to wider prefixes. */
193 if (rt->rt6i_dst.plen < 128)
194 tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
195
196 if (!rt->rt6i_peer)
197 rt6_bind_peer(rt, 1);
198 res = inet_peer_xrlim_allow(rt->rt6i_peer, tmo);
199 }
200 dst_release(dst);
201 return res;
202}
203
204/*
205 * an inline helper for the "simple" if statement below
206 * checks if parameter problem report is caused by an
207 * unrecognized IPv6 option that has the Option Type
208 * highest-order two bits set to 10
209 */
210
211static bool opt_unrec(struct sk_buff *skb, __u32 offset)
212{
213 u8 _optval, *op;
214
215 offset += skb_network_offset(skb);
216 op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
217 if (op == NULL)
218 return true;
219 return (*op & 0xC0) == 0x80;
220}
221
222static int icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6, struct icmp6hdr *thdr, int len)
223{
224 struct sk_buff *skb;
225 struct icmp6hdr *icmp6h;
226 int err = 0;
227
228 if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
229 goto out;
230
231 icmp6h = icmp6_hdr(skb);
232 memcpy(icmp6h, thdr, sizeof(struct icmp6hdr));
233 icmp6h->icmp6_cksum = 0;
234
235 if (skb_queue_len(&sk->sk_write_queue) == 1) {
236 skb->csum = csum_partial(icmp6h,
237 sizeof(struct icmp6hdr), skb->csum);
238 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
239 &fl6->daddr,
240 len, fl6->flowi6_proto,
241 skb->csum);
242 } else {
243 __wsum tmp_csum = 0;
244
245 skb_queue_walk(&sk->sk_write_queue, skb) {
246 tmp_csum = csum_add(tmp_csum, skb->csum);
247 }
248
249 tmp_csum = csum_partial(icmp6h,
250 sizeof(struct icmp6hdr), tmp_csum);
251 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
252 &fl6->daddr,
253 len, fl6->flowi6_proto,
254 tmp_csum);
255 }
256 ip6_push_pending_frames(sk);
257out:
258 return err;
259}
260
261struct icmpv6_msg {
262 struct sk_buff *skb;
263 int offset;
264 uint8_t type;
265};
266
267static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
268{
269 struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
270 struct sk_buff *org_skb = msg->skb;
271 __wsum csum = 0;
272
273 csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
274 to, len, csum);
275 skb->csum = csum_block_add(skb->csum, csum, odd);
276 if (!(msg->type & ICMPV6_INFOMSG_MASK))
277 nf_ct_attach(skb, org_skb);
278 return 0;
279}
280
281#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
282static void mip6_addr_swap(struct sk_buff *skb)
283{
284 struct ipv6hdr *iph = ipv6_hdr(skb);
285 struct inet6_skb_parm *opt = IP6CB(skb);
286 struct ipv6_destopt_hao *hao;
287 struct in6_addr tmp;
288 int off;
289
290 if (opt->dsthao) {
291 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
292 if (likely(off >= 0)) {
293 hao = (struct ipv6_destopt_hao *)
294 (skb_network_header(skb) + off);
295 tmp = iph->saddr;
296 iph->saddr = hao->addr;
297 hao->addr = tmp;
298 }
299 }
300}
301#else
302static inline void mip6_addr_swap(struct sk_buff *skb) {}
303#endif
304
305static struct dst_entry *icmpv6_route_lookup(struct net *net, struct sk_buff *skb,
306 struct sock *sk, struct flowi6 *fl6)
307{
308 struct dst_entry *dst, *dst2;
309 struct flowi6 fl2;
310 int err;
311
312 err = ip6_dst_lookup(sk, &dst, fl6);
313 if (err)
314 return ERR_PTR(err);
315
316 /*
317 * We won't send icmp if the destination is known
318 * anycast.
319 */
320 if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) {
321 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: acast source\n");
322 dst_release(dst);
323 return ERR_PTR(-EINVAL);
324 }
325
326 /* No need to clone since we're just using its address. */
327 dst2 = dst;
328
329 dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0);
330 if (!IS_ERR(dst)) {
331 if (dst != dst2)
332 return dst;
333 } else {
334 if (PTR_ERR(dst) == -EPERM)
335 dst = NULL;
336 else
337 return dst;
338 }
339
340 err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6);
341 if (err)
342 goto relookup_failed;
343
344 err = ip6_dst_lookup(sk, &dst2, &fl2);
345 if (err)
346 goto relookup_failed;
347
348 dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP);
349 if (!IS_ERR(dst2)) {
350 dst_release(dst);
351 dst = dst2;
352 } else {
353 err = PTR_ERR(dst2);
354 if (err == -EPERM) {
355 dst_release(dst);
356 return dst2;
357 } else
358 goto relookup_failed;
359 }
360
361relookup_failed:
362 if (dst)
363 return dst;
364 return ERR_PTR(err);
365}
366
367/*
368 * Send an ICMP message in response to a packet in error
369 */
370void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
371{
372 struct net *net = dev_net(skb->dev);
373 struct inet6_dev *idev = NULL;
374 struct ipv6hdr *hdr = ipv6_hdr(skb);
375 struct sock *sk;
376 struct ipv6_pinfo *np;
377 const struct in6_addr *saddr = NULL;
378 struct dst_entry *dst;
379 struct icmp6hdr tmp_hdr;
380 struct flowi6 fl6;
381 struct icmpv6_msg msg;
382 int iif = 0;
383 int addr_type = 0;
384 int len;
385 int hlimit;
386 int err = 0;
387
388 if ((u8 *)hdr < skb->head ||
389 (skb->network_header + sizeof(*hdr)) > skb->tail)
390 return;
391
392 /*
393 * Make sure we respect the rules
394 * i.e. RFC 1885 2.4(e)
395 * Rule (e.1) is enforced by not using icmpv6_send
396 * in any code that processes icmp errors.
397 */
398 addr_type = ipv6_addr_type(&hdr->daddr);
399
400 if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0))
401 saddr = &hdr->daddr;
402
403 /*
404 * Dest addr check
405 */
406
407 if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) {
408 if (type != ICMPV6_PKT_TOOBIG &&
409 !(type == ICMPV6_PARAMPROB &&
410 code == ICMPV6_UNK_OPTION &&
411 (opt_unrec(skb, info))))
412 return;
413
414 saddr = NULL;
415 }
416
417 addr_type = ipv6_addr_type(&hdr->saddr);
418
419 /*
420 * Source addr check
421 */
422
423 if (addr_type & IPV6_ADDR_LINKLOCAL)
424 iif = skb->dev->ifindex;
425
426 /*
427 * Must not send error if the source does not uniquely
428 * identify a single node (RFC2463 Section 2.4).
429 * We check unspecified / multicast addresses here,
430 * and anycast addresses will be checked later.
431 */
432 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
433 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: addr_any/mcast source\n");
434 return;
435 }
436
437 /*
438 * Never answer to a ICMP packet.
439 */
440 if (is_ineligible(skb)) {
441 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: no reply to icmp error\n");
442 return;
443 }
444
445 mip6_addr_swap(skb);
446
447 memset(&fl6, 0, sizeof(fl6));
448 fl6.flowi6_proto = IPPROTO_ICMPV6;
449 fl6.daddr = hdr->saddr;
450 if (saddr)
451 fl6.saddr = *saddr;
452 fl6.flowi6_oif = iif;
453 fl6.fl6_icmp_type = type;
454 fl6.fl6_icmp_code = code;
455 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
456
457 sk = icmpv6_xmit_lock(net);
458 if (sk == NULL)
459 return;
460 np = inet6_sk(sk);
461
462 if (!icmpv6_xrlim_allow(sk, type, &fl6))
463 goto out;
464
465 tmp_hdr.icmp6_type = type;
466 tmp_hdr.icmp6_code = code;
467 tmp_hdr.icmp6_cksum = 0;
468 tmp_hdr.icmp6_pointer = htonl(info);
469
470 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
471 fl6.flowi6_oif = np->mcast_oif;
472 else if (!fl6.flowi6_oif)
473 fl6.flowi6_oif = np->ucast_oif;
474
475 dst = icmpv6_route_lookup(net, skb, sk, &fl6);
476 if (IS_ERR(dst))
477 goto out;
478
479 if (ipv6_addr_is_multicast(&fl6.daddr))
480 hlimit = np->mcast_hops;
481 else
482 hlimit = np->hop_limit;
483 if (hlimit < 0)
484 hlimit = ip6_dst_hoplimit(dst);
485
486 msg.skb = skb;
487 msg.offset = skb_network_offset(skb);
488 msg.type = type;
489
490 len = skb->len - msg.offset;
491 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) -sizeof(struct icmp6hdr));
492 if (len < 0) {
493 LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n");
494 goto out_dst_release;
495 }
496
497 rcu_read_lock();
498 idev = __in6_dev_get(skb->dev);
499
500 err = ip6_append_data(sk, icmpv6_getfrag, &msg,
501 len + sizeof(struct icmp6hdr),
502 sizeof(struct icmp6hdr), hlimit,
503 np->tclass, NULL, &fl6, (struct rt6_info *)dst,
504 MSG_DONTWAIT, np->dontfrag);
505 if (err) {
506 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS);
507 ip6_flush_pending_frames(sk);
508 } else {
509 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
510 len + sizeof(struct icmp6hdr));
511 }
512 rcu_read_unlock();
513out_dst_release:
514 dst_release(dst);
515out:
516 icmpv6_xmit_unlock(sk);
517}
518EXPORT_SYMBOL(icmpv6_send);
519
520static void icmpv6_echo_reply(struct sk_buff *skb)
521{
522 struct net *net = dev_net(skb->dev);
523 struct sock *sk;
524 struct inet6_dev *idev;
525 struct ipv6_pinfo *np;
526 const struct in6_addr *saddr = NULL;
527 struct icmp6hdr *icmph = icmp6_hdr(skb);
528 struct icmp6hdr tmp_hdr;
529 struct flowi6 fl6;
530 struct icmpv6_msg msg;
531 struct dst_entry *dst;
532 int err = 0;
533 int hlimit;
534
535 saddr = &ipv6_hdr(skb)->daddr;
536
537 if (!ipv6_unicast_destination(skb))
538 saddr = NULL;
539
540 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
541 tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;
542
543 memset(&fl6, 0, sizeof(fl6));
544 fl6.flowi6_proto = IPPROTO_ICMPV6;
545 fl6.daddr = ipv6_hdr(skb)->saddr;
546 if (saddr)
547 fl6.saddr = *saddr;
548 fl6.flowi6_oif = skb->dev->ifindex;
549 fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY;
550 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
551
552 sk = icmpv6_xmit_lock(net);
553 if (sk == NULL)
554 return;
555 np = inet6_sk(sk);
556
557 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
558 fl6.flowi6_oif = np->mcast_oif;
559 else if (!fl6.flowi6_oif)
560 fl6.flowi6_oif = np->ucast_oif;
561
562 err = ip6_dst_lookup(sk, &dst, &fl6);
563 if (err)
564 goto out;
565 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
566 if (IS_ERR(dst))
567 goto out;
568
569 if (ipv6_addr_is_multicast(&fl6.daddr))
570 hlimit = np->mcast_hops;
571 else
572 hlimit = np->hop_limit;
573 if (hlimit < 0)
574 hlimit = ip6_dst_hoplimit(dst);
575
576 idev = __in6_dev_get(skb->dev);
577
578 msg.skb = skb;
579 msg.offset = 0;
580 msg.type = ICMPV6_ECHO_REPLY;
581
582 err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr),
583 sizeof(struct icmp6hdr), hlimit, np->tclass, NULL, &fl6,
584 (struct rt6_info *)dst, MSG_DONTWAIT,
585 np->dontfrag);
586
587 if (err) {
588 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS);
589 ip6_flush_pending_frames(sk);
590 } else {
591 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
592 skb->len + sizeof(struct icmp6hdr));
593 }
594 dst_release(dst);
595out:
596 icmpv6_xmit_unlock(sk);
597}
598
599static void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info)
600{
601 const struct inet6_protocol *ipprot;
602 int inner_offset;
603 int hash;
604 u8 nexthdr;
605 __be16 frag_off;
606
607 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
608 return;
609
610 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
611 if (ipv6_ext_hdr(nexthdr)) {
612 /* now skip over extension headers */
613 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
614 &nexthdr, &frag_off);
615 if (inner_offset<0)
616 return;
617 } else {
618 inner_offset = sizeof(struct ipv6hdr);
619 }
620
621 /* Checkin header including 8 bytes of inner protocol header. */
622 if (!pskb_may_pull(skb, inner_offset+8))
623 return;
624
625 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
626 Without this we will not able f.e. to make source routed
627 pmtu discovery.
628 Corresponding argument (opt) to notifiers is already added.
629 --ANK (980726)
630 */
631
632 hash = nexthdr & (MAX_INET_PROTOS - 1);
633
634 rcu_read_lock();
635 ipprot = rcu_dereference(inet6_protos[hash]);
636 if (ipprot && ipprot->err_handler)
637 ipprot->err_handler(skb, NULL, type, code, inner_offset, info);
638 rcu_read_unlock();
639
640 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
641}
642
643/*
644 * Handle icmp messages
645 */
646
647static int icmpv6_rcv(struct sk_buff *skb)
648{
649 struct net_device *dev = skb->dev;
650 struct inet6_dev *idev = __in6_dev_get(dev);
651 const struct in6_addr *saddr, *daddr;
652 const struct ipv6hdr *orig_hdr;
653 struct icmp6hdr *hdr;
654 u8 type;
655
656 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
657 struct sec_path *sp = skb_sec_path(skb);
658 int nh;
659
660 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
661 XFRM_STATE_ICMP))
662 goto drop_no_count;
663
664 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(*orig_hdr)))
665 goto drop_no_count;
666
667 nh = skb_network_offset(skb);
668 skb_set_network_header(skb, sizeof(*hdr));
669
670 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
671 goto drop_no_count;
672
673 skb_set_network_header(skb, nh);
674 }
675
676 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INMSGS);
677
678 saddr = &ipv6_hdr(skb)->saddr;
679 daddr = &ipv6_hdr(skb)->daddr;
680
681 /* Perform checksum. */
682 switch (skb->ip_summed) {
683 case CHECKSUM_COMPLETE:
684 if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6,
685 skb->csum))
686 break;
687 /* fall through */
688 case CHECKSUM_NONE:
689 skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len,
690 IPPROTO_ICMPV6, 0));
691 if (__skb_checksum_complete(skb)) {
692 LIMIT_NETDEBUG(KERN_DEBUG "ICMPv6 checksum failed [%pI6 > %pI6]\n",
693 saddr, daddr);
694 goto discard_it;
695 }
696 }
697
698 if (!pskb_pull(skb, sizeof(*hdr)))
699 goto discard_it;
700
701 hdr = icmp6_hdr(skb);
702
703 type = hdr->icmp6_type;
704
705 ICMP6MSGIN_INC_STATS_BH(dev_net(dev), idev, type);
706
707 switch (type) {
708 case ICMPV6_ECHO_REQUEST:
709 icmpv6_echo_reply(skb);
710 break;
711
712 case ICMPV6_ECHO_REPLY:
713 /* we couldn't care less */
714 break;
715
716 case ICMPV6_PKT_TOOBIG:
717 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
718 standard destination cache. Seems, only "advanced"
719 destination cache will allow to solve this problem
720 --ANK (980726)
721 */
722 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
723 goto discard_it;
724 hdr = icmp6_hdr(skb);
725 orig_hdr = (struct ipv6hdr *) (hdr + 1);
726 rt6_pmtu_discovery(&orig_hdr->daddr, &orig_hdr->saddr, dev,
727 ntohl(hdr->icmp6_mtu));
728
729 /*
730 * Drop through to notify
731 */
732
733 case ICMPV6_DEST_UNREACH:
734 case ICMPV6_TIME_EXCEED:
735 case ICMPV6_PARAMPROB:
736 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
737 break;
738
739 case NDISC_ROUTER_SOLICITATION:
740 case NDISC_ROUTER_ADVERTISEMENT:
741 case NDISC_NEIGHBOUR_SOLICITATION:
742 case NDISC_NEIGHBOUR_ADVERTISEMENT:
743 case NDISC_REDIRECT:
744 ndisc_rcv(skb);
745 break;
746
747 case ICMPV6_MGM_QUERY:
748 igmp6_event_query(skb);
749 break;
750
751 case ICMPV6_MGM_REPORT:
752 igmp6_event_report(skb);
753 break;
754
755 case ICMPV6_MGM_REDUCTION:
756 case ICMPV6_NI_QUERY:
757 case ICMPV6_NI_REPLY:
758 case ICMPV6_MLD2_REPORT:
759 case ICMPV6_DHAAD_REQUEST:
760 case ICMPV6_DHAAD_REPLY:
761 case ICMPV6_MOBILE_PREFIX_SOL:
762 case ICMPV6_MOBILE_PREFIX_ADV:
763 break;
764
765 default:
766 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n");
767
768 /* informational */
769 if (type & ICMPV6_INFOMSG_MASK)
770 break;
771
772 /*
773 * error of unknown type.
774 * must pass to upper level
775 */
776
777 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
778 }
779
780 kfree_skb(skb);
781 return 0;
782
783discard_it:
784 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INERRORS);
785drop_no_count:
786 kfree_skb(skb);
787 return 0;
788}
789
790void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6,
791 u8 type,
792 const struct in6_addr *saddr,
793 const struct in6_addr *daddr,
794 int oif)
795{
796 memset(fl6, 0, sizeof(*fl6));
797 fl6->saddr = *saddr;
798 fl6->daddr = *daddr;
799 fl6->flowi6_proto = IPPROTO_ICMPV6;
800 fl6->fl6_icmp_type = type;
801 fl6->fl6_icmp_code = 0;
802 fl6->flowi6_oif = oif;
803 security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
804}
805
806/*
807 * Special lock-class for __icmpv6_sk:
808 */
809static struct lock_class_key icmpv6_socket_sk_dst_lock_key;
810
811static int __net_init icmpv6_sk_init(struct net *net)
812{
813 struct sock *sk;
814 int err, i, j;
815
816 net->ipv6.icmp_sk =
817 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL);
818 if (net->ipv6.icmp_sk == NULL)
819 return -ENOMEM;
820
821 for_each_possible_cpu(i) {
822 err = inet_ctl_sock_create(&sk, PF_INET6,
823 SOCK_RAW, IPPROTO_ICMPV6, net);
824 if (err < 0) {
825 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n",
826 err);
827 goto fail;
828 }
829
830 net->ipv6.icmp_sk[i] = sk;
831
832 /*
833 * Split off their lock-class, because sk->sk_dst_lock
834 * gets used from softirqs, which is safe for
835 * __icmpv6_sk (because those never get directly used
836 * via userspace syscalls), but unsafe for normal sockets.
837 */
838 lockdep_set_class(&sk->sk_dst_lock,
839 &icmpv6_socket_sk_dst_lock_key);
840
841 /* Enough space for 2 64K ICMP packets, including
842 * sk_buff struct overhead.
843 */
844 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
845 }
846 return 0;
847
848 fail:
849 for (j = 0; j < i; j++)
850 inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]);
851 kfree(net->ipv6.icmp_sk);
852 return err;
853}
854
855static void __net_exit icmpv6_sk_exit(struct net *net)
856{
857 int i;
858
859 for_each_possible_cpu(i) {
860 inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]);
861 }
862 kfree(net->ipv6.icmp_sk);
863}
864
865static struct pernet_operations icmpv6_sk_ops = {
866 .init = icmpv6_sk_init,
867 .exit = icmpv6_sk_exit,
868};
869
870int __init icmpv6_init(void)
871{
872 int err;
873
874 err = register_pernet_subsys(&icmpv6_sk_ops);
875 if (err < 0)
876 return err;
877
878 err = -EAGAIN;
879 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0)
880 goto fail;
881 return 0;
882
883fail:
884 pr_err("Failed to register ICMP6 protocol\n");
885 unregister_pernet_subsys(&icmpv6_sk_ops);
886 return err;
887}
888
889void icmpv6_cleanup(void)
890{
891 unregister_pernet_subsys(&icmpv6_sk_ops);
892 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
893}
894
895
896static const struct icmp6_err {
897 int err;
898 int fatal;
899} tab_unreach[] = {
900 { /* NOROUTE */
901 .err = ENETUNREACH,
902 .fatal = 0,
903 },
904 { /* ADM_PROHIBITED */
905 .err = EACCES,
906 .fatal = 1,
907 },
908 { /* Was NOT_NEIGHBOUR, now reserved */
909 .err = EHOSTUNREACH,
910 .fatal = 0,
911 },
912 { /* ADDR_UNREACH */
913 .err = EHOSTUNREACH,
914 .fatal = 0,
915 },
916 { /* PORT_UNREACH */
917 .err = ECONNREFUSED,
918 .fatal = 1,
919 },
920};
921
922int icmpv6_err_convert(u8 type, u8 code, int *err)
923{
924 int fatal = 0;
925
926 *err = EPROTO;
927
928 switch (type) {
929 case ICMPV6_DEST_UNREACH:
930 fatal = 1;
931 if (code <= ICMPV6_PORT_UNREACH) {
932 *err = tab_unreach[code].err;
933 fatal = tab_unreach[code].fatal;
934 }
935 break;
936
937 case ICMPV6_PKT_TOOBIG:
938 *err = EMSGSIZE;
939 break;
940
941 case ICMPV6_PARAMPROB:
942 *err = EPROTO;
943 fatal = 1;
944 break;
945
946 case ICMPV6_TIME_EXCEED:
947 *err = EHOSTUNREACH;
948 break;
949 }
950
951 return fatal;
952}
953EXPORT_SYMBOL(icmpv6_err_convert);
954
955#ifdef CONFIG_SYSCTL
956ctl_table ipv6_icmp_table_template[] = {
957 {
958 .procname = "ratelimit",
959 .data = &init_net.ipv6.sysctl.icmpv6_time,
960 .maxlen = sizeof(int),
961 .mode = 0644,
962 .proc_handler = proc_dointvec_ms_jiffies,
963 },
964 { },
965};
966
967struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
968{
969 struct ctl_table *table;
970
971 table = kmemdup(ipv6_icmp_table_template,
972 sizeof(ipv6_icmp_table_template),
973 GFP_KERNEL);
974
975 if (table)
976 table[0].data = &net->ipv6.sysctl.icmpv6_time;
977
978 return table;
979}
980#endif
981