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