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
71 #include <asm/uaccess.h>
72
73 /*
74 * The ICMP socket(s). This is the most convenient way to flow control
75 * our ICMP output as well as maintain a clean interface throughout
76 * all layers. All Socketless IP sends will soon be gone.
77 *
78 * On SMP we have one ICMP socket per-cpu.
79 */
icmpv6_sk(struct net * net)80 static inline struct sock *icmpv6_sk(struct net *net)
81 {
82 return net->ipv6.icmp_sk[smp_processor_id()];
83 }
84
icmpv6_err(struct sk_buff * skb,struct inet6_skb_parm * opt,u8 type,u8 code,int offset,__be32 info)85 static void icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
86 u8 type, u8 code, int offset, __be32 info)
87 {
88 /* icmpv6_notify checks 8 bytes can be pulled, icmp6hdr is 8 bytes */
89 struct icmp6hdr *icmp6 = (struct icmp6hdr *) (skb->data + offset);
90 struct net *net = dev_net(skb->dev);
91
92 if (type == ICMPV6_PKT_TOOBIG)
93 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
94 else if (type == NDISC_REDIRECT)
95 ip6_redirect(skb, net, 0, 0, sock_net_uid(net, NULL));
96
97 if (!(type & ICMPV6_INFOMSG_MASK))
98 if (icmp6->icmp6_type == ICMPV6_ECHO_REQUEST)
99 ping_err(skb, offset, ntohl(info));
100 }
101
102 static int icmpv6_rcv(struct sk_buff *skb);
103
104 static const struct inet6_protocol icmpv6_protocol = {
105 .handler = icmpv6_rcv,
106 .err_handler = icmpv6_err,
107 .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
108 };
109
icmpv6_xmit_lock(struct net * net)110 static __inline__ struct sock *icmpv6_xmit_lock(struct net *net)
111 {
112 struct sock *sk;
113
114 local_bh_disable();
115
116 sk = icmpv6_sk(net);
117 if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
118 /* This can happen if the output path (f.e. SIT or
119 * ip6ip6 tunnel) signals dst_link_failure() for an
120 * outgoing ICMP6 packet.
121 */
122 local_bh_enable();
123 return NULL;
124 }
125 return sk;
126 }
127
icmpv6_xmit_unlock(struct sock * sk)128 static __inline__ void icmpv6_xmit_unlock(struct sock *sk)
129 {
130 spin_unlock_bh(&sk->sk_lock.slock);
131 }
132
133 /*
134 * Figure out, may we reply to this packet with icmp error.
135 *
136 * We do not reply, if:
137 * - it was icmp error message.
138 * - it is truncated, so that it is known, that protocol is ICMPV6
139 * (i.e. in the middle of some exthdr)
140 *
141 * --ANK (980726)
142 */
143
is_ineligible(const struct sk_buff * skb)144 static bool is_ineligible(const struct sk_buff *skb)
145 {
146 int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
147 int len = skb->len - ptr;
148 __u8 nexthdr = ipv6_hdr(skb)->nexthdr;
149 __be16 frag_off;
150
151 if (len < 0)
152 return true;
153
154 ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off);
155 if (ptr < 0)
156 return false;
157 if (nexthdr == IPPROTO_ICMPV6) {
158 u8 _type, *tp;
159 tp = skb_header_pointer(skb,
160 ptr+offsetof(struct icmp6hdr, icmp6_type),
161 sizeof(_type), &_type);
162 if (tp == NULL ||
163 !(*tp & ICMPV6_INFOMSG_MASK))
164 return true;
165 }
166 return false;
167 }
168
169 /*
170 * Check the ICMP output rate limit
171 */
icmpv6_xrlim_allow(struct sock * sk,u8 type,struct flowi6 * fl6)172 static inline bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
173 struct flowi6 *fl6)
174 {
175 struct dst_entry *dst;
176 struct net *net = sock_net(sk);
177 bool res = false;
178
179 /* Informational messages are not limited. */
180 if (type & ICMPV6_INFOMSG_MASK)
181 return true;
182
183 /* Do not limit pmtu discovery, it would break it. */
184 if (type == ICMPV6_PKT_TOOBIG)
185 return true;
186
187 /*
188 * Look up the output route.
189 * XXX: perhaps the expire for routing entries cloned by
190 * this lookup should be more aggressive (not longer than timeout).
191 */
192 dst = ip6_route_output(net, sk, fl6);
193 if (dst->error) {
194 IP6_INC_STATS(net, ip6_dst_idev(dst),
195 IPSTATS_MIB_OUTNOROUTES);
196 } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
197 res = true;
198 } else {
199 struct rt6_info *rt = (struct rt6_info *)dst;
200 int tmo = net->ipv6.sysctl.icmpv6_time;
201 struct inet_peer *peer;
202
203 /* Give more bandwidth to wider prefixes. */
204 if (rt->rt6i_dst.plen < 128)
205 tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
206
207 peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
208 res = inet_peer_xrlim_allow(peer, tmo);
209 if (peer)
210 inet_putpeer(peer);
211 }
212 dst_release(dst);
213 return res;
214 }
215
216 /*
217 * an inline helper for the "simple" if statement below
218 * checks if parameter problem report is caused by an
219 * unrecognized IPv6 option that has the Option Type
220 * highest-order two bits set to 10
221 */
222
opt_unrec(struct sk_buff * skb,__u32 offset)223 static bool opt_unrec(struct sk_buff *skb, __u32 offset)
224 {
225 u8 _optval, *op;
226
227 offset += skb_network_offset(skb);
228 op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
229 if (op == NULL)
230 return true;
231 return (*op & 0xC0) == 0x80;
232 }
233
icmpv6_push_pending_frames(struct sock * sk,struct flowi6 * fl6,struct icmp6hdr * thdr,int len)234 int icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6,
235 struct icmp6hdr *thdr, int len)
236 {
237 struct sk_buff *skb;
238 struct icmp6hdr *icmp6h;
239 int err = 0;
240
241 if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
242 goto out;
243
244 icmp6h = icmp6_hdr(skb);
245 memcpy(icmp6h, thdr, sizeof(struct icmp6hdr));
246 icmp6h->icmp6_cksum = 0;
247
248 if (skb_queue_len(&sk->sk_write_queue) == 1) {
249 skb->csum = csum_partial(icmp6h,
250 sizeof(struct icmp6hdr), skb->csum);
251 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
252 &fl6->daddr,
253 len, fl6->flowi6_proto,
254 skb->csum);
255 } else {
256 __wsum tmp_csum = 0;
257
258 skb_queue_walk(&sk->sk_write_queue, skb) {
259 tmp_csum = csum_add(tmp_csum, skb->csum);
260 }
261
262 tmp_csum = csum_partial(icmp6h,
263 sizeof(struct icmp6hdr), tmp_csum);
264 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
265 &fl6->daddr,
266 len, fl6->flowi6_proto,
267 tmp_csum);
268 }
269 ip6_push_pending_frames(sk);
270 out:
271 return err;
272 }
273
274 struct icmpv6_msg {
275 struct sk_buff *skb;
276 int offset;
277 uint8_t type;
278 };
279
icmpv6_getfrag(void * from,char * to,int offset,int len,int odd,struct sk_buff * skb)280 static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
281 {
282 struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
283 struct sk_buff *org_skb = msg->skb;
284 __wsum csum = 0;
285
286 csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
287 to, len, csum);
288 skb->csum = csum_block_add(skb->csum, csum, odd);
289 if (!(msg->type & ICMPV6_INFOMSG_MASK))
290 nf_ct_attach(skb, org_skb);
291 return 0;
292 }
293
294 #if IS_ENABLED(CONFIG_IPV6_MIP6)
mip6_addr_swap(struct sk_buff * skb)295 static void mip6_addr_swap(struct sk_buff *skb)
296 {
297 struct ipv6hdr *iph = ipv6_hdr(skb);
298 struct inet6_skb_parm *opt = IP6CB(skb);
299 struct ipv6_destopt_hao *hao;
300 struct in6_addr tmp;
301 int off;
302
303 if (opt->dsthao) {
304 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
305 if (likely(off >= 0)) {
306 hao = (struct ipv6_destopt_hao *)
307 (skb_network_header(skb) + off);
308 tmp = iph->saddr;
309 iph->saddr = hao->addr;
310 hao->addr = tmp;
311 }
312 }
313 }
314 #else
mip6_addr_swap(struct sk_buff * skb)315 static inline void mip6_addr_swap(struct sk_buff *skb) {}
316 #endif
317
icmpv6_route_lookup(struct net * net,struct sk_buff * skb,struct sock * sk,struct flowi6 * fl6)318 struct dst_entry *icmpv6_route_lookup(struct net *net, struct sk_buff *skb,
319 struct sock *sk, struct flowi6 *fl6)
320 {
321 struct dst_entry *dst, *dst2;
322 struct flowi6 fl2;
323 int err;
324
325 err = ip6_dst_lookup(sk, &dst, fl6);
326 if (err)
327 return ERR_PTR(err);
328
329 /*
330 * We won't send icmp if the destination is known
331 * anycast.
332 */
333 if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) {
334 LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: acast source\n");
335 dst_release(dst);
336 return ERR_PTR(-EINVAL);
337 }
338
339 /* No need to clone since we're just using its address. */
340 dst2 = dst;
341
342 dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0);
343 if (!IS_ERR(dst)) {
344 if (dst != dst2)
345 return dst;
346 } else {
347 if (PTR_ERR(dst) == -EPERM)
348 dst = NULL;
349 else
350 return dst;
351 }
352
353 err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6);
354 if (err)
355 goto relookup_failed;
356
357 err = ip6_dst_lookup(sk, &dst2, &fl2);
358 if (err)
359 goto relookup_failed;
360
361 dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP);
362 if (!IS_ERR(dst2)) {
363 dst_release(dst);
364 dst = dst2;
365 } else {
366 err = PTR_ERR(dst2);
367 if (err == -EPERM) {
368 dst_release(dst);
369 return dst2;
370 } else
371 goto relookup_failed;
372 }
373
374 relookup_failed:
375 if (dst)
376 return dst;
377 return ERR_PTR(err);
378 }
379
380 /*
381 * Send an ICMP message in response to a packet in error
382 */
icmp6_send(struct sk_buff * skb,u8 type,u8 code,__u32 info)383 static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
384 {
385 struct net *net = dev_net(skb->dev);
386 struct inet6_dev *idev = NULL;
387 struct ipv6hdr *hdr = ipv6_hdr(skb);
388 struct sock *sk;
389 struct ipv6_pinfo *np;
390 const struct in6_addr *saddr = NULL;
391 struct dst_entry *dst;
392 struct icmp6hdr tmp_hdr;
393 struct flowi6 fl6;
394 struct icmpv6_msg msg;
395 int iif = 0;
396 int addr_type = 0;
397 int len;
398 int hlimit;
399 int err = 0;
400 u32 mark = IP6_REPLY_MARK(net, skb->mark);
401
402 if ((u8 *)hdr < skb->head ||
403 (skb->network_header + sizeof(*hdr)) > skb->tail)
404 return;
405
406 /*
407 * Make sure we respect the rules
408 * i.e. RFC 1885 2.4(e)
409 * Rule (e.1) is enforced by not using icmp6_send
410 * in any code that processes icmp errors.
411 */
412 addr_type = ipv6_addr_type(&hdr->daddr);
413
414 if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0))
415 saddr = &hdr->daddr;
416
417 /*
418 * Dest addr check
419 */
420
421 if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) {
422 if (type != ICMPV6_PKT_TOOBIG &&
423 !(type == ICMPV6_PARAMPROB &&
424 code == ICMPV6_UNK_OPTION &&
425 (opt_unrec(skb, info))))
426 return;
427
428 saddr = NULL;
429 }
430
431 addr_type = ipv6_addr_type(&hdr->saddr);
432
433 /*
434 * Source addr check
435 */
436
437 if (__ipv6_addr_needs_scope_id(addr_type))
438 iif = skb->dev->ifindex;
439
440 /*
441 * Must not send error if the source does not uniquely
442 * identify a single node (RFC2463 Section 2.4).
443 * We check unspecified / multicast addresses here,
444 * and anycast addresses will be checked later.
445 */
446 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
447 LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: addr_any/mcast source\n");
448 return;
449 }
450
451 /*
452 * Never answer to a ICMP packet.
453 */
454 if (is_ineligible(skb)) {
455 LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: no reply to icmp error\n");
456 return;
457 }
458
459 mip6_addr_swap(skb);
460
461 memset(&fl6, 0, sizeof(fl6));
462 fl6.flowi6_proto = IPPROTO_ICMPV6;
463 fl6.daddr = hdr->saddr;
464 if (saddr)
465 fl6.saddr = *saddr;
466 fl6.flowi6_mark = mark;
467 fl6.flowi6_oif = iif;
468 fl6.fl6_icmp_type = type;
469 fl6.fl6_icmp_code = code;
470 fl6.flowi6_uid = sock_net_uid(net, NULL);
471 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
472
473 sk = icmpv6_xmit_lock(net);
474 if (sk == NULL)
475 return;
476 sk->sk_mark = mark;
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_BH(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();
530 out_dst_release:
531 dst_release(dst);
532 out:
533 icmpv6_xmit_unlock(sk);
534 }
535
536 /* Slightly more convenient version of icmp6_send.
537 */
icmpv6_param_prob(struct sk_buff * skb,u8 code,int pos)538 void 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
icmpv6_echo_reply(struct sk_buff * skb)544 static 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 u32 mark = IP6_REPLY_MARK(net, skb->mark);
559
560 saddr = &ipv6_hdr(skb)->daddr;
561
562 if (!ipv6_unicast_destination(skb))
563 saddr = NULL;
564
565 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
566 tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;
567
568 memset(&fl6, 0, sizeof(fl6));
569 fl6.flowi6_proto = IPPROTO_ICMPV6;
570 fl6.daddr = ipv6_hdr(skb)->saddr;
571 if (saddr)
572 fl6.saddr = *saddr;
573 fl6.flowi6_oif = skb->dev->ifindex;
574 fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY;
575 fl6.flowi6_mark = mark;
576 fl6.flowi6_uid = sock_net_uid(net, NULL);
577 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
578
579 sk = icmpv6_xmit_lock(net);
580 if (sk == NULL)
581 return;
582 sk->sk_mark = mark;
583 np = inet6_sk(sk);
584
585 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
586 fl6.flowi6_oif = np->mcast_oif;
587 else if (!fl6.flowi6_oif)
588 fl6.flowi6_oif = np->ucast_oif;
589
590 err = ip6_dst_lookup(sk, &dst, &fl6);
591 if (err)
592 goto out;
593 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
594 if (IS_ERR(dst))
595 goto out;
596
597 if (ipv6_addr_is_multicast(&fl6.daddr))
598 hlimit = np->mcast_hops;
599 else
600 hlimit = np->hop_limit;
601 if (hlimit < 0)
602 hlimit = ip6_dst_hoplimit(dst);
603
604 idev = __in6_dev_get(skb->dev);
605
606 msg.skb = skb;
607 msg.offset = 0;
608 msg.type = ICMPV6_ECHO_REPLY;
609
610 err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr),
611 sizeof(struct icmp6hdr), hlimit, np->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);
623 out:
624 icmpv6_xmit_unlock(sk);
625 }
626
icmpv6_notify(struct sk_buff * skb,u8 type,u8 code,__be32 info)627 void 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
icmpv6_rcv(struct sk_buff * skb)672 static 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
805 csum_error:
806 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS);
807 discard_it:
808 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INERRORS);
809 drop_no_count:
810 kfree_skb(skb);
811 return 0;
812 }
813
icmpv6_flow_init(struct sock * sk,struct flowi6 * fl6,u8 type,const struct in6_addr * saddr,const struct in6_addr * daddr,int oif)814 void 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 */
833 static struct lock_class_key icmpv6_socket_sk_dst_lock_key;
834
icmpv6_sk_init(struct net * net)835 static 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
icmpv6_sk_exit(struct net * net)879 static 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
889 static struct pernet_operations icmpv6_sk_ops = {
890 .init = icmpv6_sk_init,
891 .exit = icmpv6_sk_exit,
892 };
893
icmpv6_init(void)894 int __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
911 sender_reg_err:
912 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
913 fail:
914 pr_err("Failed to register ICMP6 protocol\n");
915 unregister_pernet_subsys(&icmpv6_sk_ops);
916 return err;
917 }
918
icmpv6_cleanup(void)919 void 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
927 static 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 };
952
icmpv6_err_convert(u8 type,u8 code,int * err)953 int icmpv6_err_convert(u8 type, u8 code, int *err)
954 {
955 int fatal = 0;
956
957 *err = EPROTO;
958
959 switch (type) {
960 case ICMPV6_DEST_UNREACH:
961 fatal = 1;
962 if (code <= ICMPV6_PORT_UNREACH) {
963 *err = tab_unreach[code].err;
964 fatal = tab_unreach[code].fatal;
965 }
966 break;
967
968 case ICMPV6_PKT_TOOBIG:
969 *err = EMSGSIZE;
970 break;
971
972 case ICMPV6_PARAMPROB:
973 *err = EPROTO;
974 fatal = 1;
975 break;
976
977 case ICMPV6_TIME_EXCEED:
978 *err = EHOSTUNREACH;
979 break;
980 }
981
982 return fatal;
983 }
984 EXPORT_SYMBOL(icmpv6_err_convert);
985
986 #ifdef CONFIG_SYSCTL
987 ctl_table ipv6_icmp_table_template[] = {
988 {
989 .procname = "ratelimit",
990 .data = &init_net.ipv6.sysctl.icmpv6_time,
991 .maxlen = sizeof(int),
992 .mode = 0644,
993 .proc_handler = proc_dointvec_ms_jiffies,
994 },
995 { },
996 };
997
ipv6_icmp_sysctl_init(struct net * net)998 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
999 {
1000 struct ctl_table *table;
1001
1002 table = kmemdup(ipv6_icmp_table_template,
1003 sizeof(ipv6_icmp_table_template),
1004 GFP_KERNEL);
1005
1006 if (table)
1007 table[0].data = &net->ipv6.sysctl.icmpv6_time;
1008
1009 return table;
1010 }
1011 #endif
1012
1013