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1/*
2 * NET3: Implementation of the ICMP protocol layer.
3 *
4 * Alan Cox, <alan@lxorguk.ukuu.org.uk>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 * Some of the function names and the icmp unreach table for this
12 * module were derived from [icmp.c 1.0.11 06/02/93] by
13 * Ross Biro, Fred N. van Kempen, Mark Evans, Alan Cox, Gerhard Koerting.
14 * Other than that this module is a complete rewrite.
15 *
16 * Fixes:
17 * Clemens Fruhwirth : introduce global icmp rate limiting
18 * with icmp type masking ability instead
19 * of broken per type icmp timeouts.
20 * Mike Shaver : RFC1122 checks.
21 * Alan Cox : Multicast ping reply as self.
22 * Alan Cox : Fix atomicity lockup in ip_build_xmit
23 * call.
24 * Alan Cox : Added 216,128 byte paths to the MTU
25 * code.
26 * Martin Mares : RFC1812 checks.
27 * Martin Mares : Can be configured to follow redirects
28 * if acting as a router _without_ a
29 * routing protocol (RFC 1812).
30 * Martin Mares : Echo requests may be configured to
31 * be ignored (RFC 1812).
32 * Martin Mares : Limitation of ICMP error message
33 * transmit rate (RFC 1812).
34 * Martin Mares : TOS and Precedence set correctly
35 * (RFC 1812).
36 * Martin Mares : Now copying as much data from the
37 * original packet as we can without
38 * exceeding 576 bytes (RFC 1812).
39 * Willy Konynenberg : Transparent proxying support.
40 * Keith Owens : RFC1191 correction for 4.2BSD based
41 * path MTU bug.
42 * Thomas Quinot : ICMP Dest Unreach codes up to 15 are
43 * valid (RFC 1812).
44 * Andi Kleen : Check all packet lengths properly
45 * and moved all kfree_skb() up to
46 * icmp_rcv.
47 * Andi Kleen : Move the rate limit bookkeeping
48 * into the dest entry and use a token
49 * bucket filter (thanks to ANK). Make
50 * the rates sysctl configurable.
51 * Yu Tianli : Fixed two ugly bugs in icmp_send
52 * - IP option length was accounted wrongly
53 * - ICMP header length was not accounted
54 * at all.
55 * Tristan Greaves : Added sysctl option to ignore bogus
56 * broadcast responses from broken routers.
57 *
58 * To Fix:
59 *
60 * - Should use skb_pull() instead of all the manual checking.
61 * This would also greatly simply some upper layer error handlers. --AK
62 *
63 */
64
65#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
66
67#include <linux/module.h>
68#include <linux/types.h>
69#include <linux/jiffies.h>
70#include <linux/kernel.h>
71#include <linux/fcntl.h>
72#include <linux/socket.h>
73#include <linux/in.h>
74#include <linux/inet.h>
75#include <linux/inetdevice.h>
76#include <linux/netdevice.h>
77#include <linux/string.h>
78#include <linux/netfilter_ipv4.h>
79#include <linux/slab.h>
80#include <net/snmp.h>
81#include <net/ip.h>
82#include <net/route.h>
83#include <net/protocol.h>
84#include <net/icmp.h>
85#include <net/tcp.h>
86#include <net/udp.h>
87#include <net/raw.h>
88#include <net/ping.h>
89#include <linux/skbuff.h>
90#include <net/sock.h>
91#include <linux/errno.h>
92#include <linux/timer.h>
93#include <linux/init.h>
94#include <linux/uaccess.h>
95#include <net/checksum.h>
96#include <net/xfrm.h>
97#include <net/inet_common.h>
98#include <net/ip_fib.h>
99#include <net/l3mdev.h>
100
101/*
102 * Build xmit assembly blocks
103 */
104
105struct icmp_bxm {
106 struct sk_buff *skb;
107 int offset;
108 int data_len;
109
110 struct {
111 struct icmphdr icmph;
112 __be32 times[3];
113 } data;
114 int head_len;
115 struct ip_options_data replyopts;
116};
117
118/* An array of errno for error messages from dest unreach. */
119/* RFC 1122: 3.2.2.1 States that NET_UNREACH, HOST_UNREACH and SR_FAILED MUST be considered 'transient errs'. */
120
121const struct icmp_err icmp_err_convert[] = {
122 {
123 .errno = ENETUNREACH, /* ICMP_NET_UNREACH */
124 .fatal = 0,
125 },
126 {
127 .errno = EHOSTUNREACH, /* ICMP_HOST_UNREACH */
128 .fatal = 0,
129 },
130 {
131 .errno = ENOPROTOOPT /* ICMP_PROT_UNREACH */,
132 .fatal = 1,
133 },
134 {
135 .errno = ECONNREFUSED, /* ICMP_PORT_UNREACH */
136 .fatal = 1,
137 },
138 {
139 .errno = EMSGSIZE, /* ICMP_FRAG_NEEDED */
140 .fatal = 0,
141 },
142 {
143 .errno = EOPNOTSUPP, /* ICMP_SR_FAILED */
144 .fatal = 0,
145 },
146 {
147 .errno = ENETUNREACH, /* ICMP_NET_UNKNOWN */
148 .fatal = 1,
149 },
150 {
151 .errno = EHOSTDOWN, /* ICMP_HOST_UNKNOWN */
152 .fatal = 1,
153 },
154 {
155 .errno = ENONET, /* ICMP_HOST_ISOLATED */
156 .fatal = 1,
157 },
158 {
159 .errno = ENETUNREACH, /* ICMP_NET_ANO */
160 .fatal = 1,
161 },
162 {
163 .errno = EHOSTUNREACH, /* ICMP_HOST_ANO */
164 .fatal = 1,
165 },
166 {
167 .errno = ENETUNREACH, /* ICMP_NET_UNR_TOS */
168 .fatal = 0,
169 },
170 {
171 .errno = EHOSTUNREACH, /* ICMP_HOST_UNR_TOS */
172 .fatal = 0,
173 },
174 {
175 .errno = EHOSTUNREACH, /* ICMP_PKT_FILTERED */
176 .fatal = 1,
177 },
178 {
179 .errno = EHOSTUNREACH, /* ICMP_PREC_VIOLATION */
180 .fatal = 1,
181 },
182 {
183 .errno = EHOSTUNREACH, /* ICMP_PREC_CUTOFF */
184 .fatal = 1,
185 },
186};
187EXPORT_SYMBOL(icmp_err_convert);
188
189/*
190 * ICMP control array. This specifies what to do with each ICMP.
191 */
192
193struct icmp_control {
194 bool (*handler)(struct sk_buff *skb);
195 short error; /* This ICMP is classed as an error message */
196};
197
198static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1];
199
200/*
201 * The ICMP socket(s). This is the most convenient way to flow control
202 * our ICMP output as well as maintain a clean interface throughout
203 * all layers. All Socketless IP sends will soon be gone.
204 *
205 * On SMP we have one ICMP socket per-cpu.
206 */
207static struct sock *icmp_sk(struct net *net)
208{
209 return *this_cpu_ptr(net->ipv4.icmp_sk);
210}
211
212/* Called with BH disabled */
213static inline struct sock *icmp_xmit_lock(struct net *net)
214{
215 struct sock *sk;
216
217 sk = icmp_sk(net);
218
219 if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
220 /* This can happen if the output path signals a
221 * dst_link_failure() for an outgoing ICMP packet.
222 */
223 return NULL;
224 }
225 return sk;
226}
227
228static inline void icmp_xmit_unlock(struct sock *sk)
229{
230 spin_unlock(&sk->sk_lock.slock);
231}
232
233int sysctl_icmp_msgs_per_sec __read_mostly = 1000;
234int sysctl_icmp_msgs_burst __read_mostly = 50;
235
236static struct {
237 spinlock_t lock;
238 u32 credit;
239 u32 stamp;
240} icmp_global = {
241 .lock = __SPIN_LOCK_UNLOCKED(icmp_global.lock),
242};
243
244/**
245 * icmp_global_allow - Are we allowed to send one more ICMP message ?
246 *
247 * Uses a token bucket to limit our ICMP messages to sysctl_icmp_msgs_per_sec.
248 * Returns false if we reached the limit and can not send another packet.
249 * Note: called with BH disabled
250 */
251bool icmp_global_allow(void)
252{
253 u32 credit, delta, incr = 0, now = (u32)jiffies;
254 bool rc = false;
255
256 /* Check if token bucket is empty and cannot be refilled
257 * without taking the spinlock.
258 */
259 if (!icmp_global.credit) {
260 delta = min_t(u32, now - icmp_global.stamp, HZ);
261 if (delta < HZ / 50)
262 return false;
263 }
264
265 spin_lock(&icmp_global.lock);
266 delta = min_t(u32, now - icmp_global.stamp, HZ);
267 if (delta >= HZ / 50) {
268 incr = sysctl_icmp_msgs_per_sec * delta / HZ ;
269 if (incr)
270 icmp_global.stamp = now;
271 }
272 credit = min_t(u32, icmp_global.credit + incr, sysctl_icmp_msgs_burst);
273 if (credit) {
274 credit--;
275 rc = true;
276 }
277 icmp_global.credit = credit;
278 spin_unlock(&icmp_global.lock);
279 return rc;
280}
281EXPORT_SYMBOL(icmp_global_allow);
282
283static bool icmpv4_mask_allow(struct net *net, int type, int code)
284{
285 if (type > NR_ICMP_TYPES)
286 return true;
287
288 /* Don't limit PMTU discovery. */
289 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
290 return true;
291
292 /* Limit if icmp type is enabled in ratemask. */
293 if (!((1 << type) & net->ipv4.sysctl_icmp_ratemask))
294 return true;
295
296 return false;
297}
298
299static bool icmpv4_global_allow(struct net *net, int type, int code)
300{
301 if (icmpv4_mask_allow(net, type, code))
302 return true;
303
304 if (icmp_global_allow())
305 return true;
306
307 return false;
308}
309
310/*
311 * Send an ICMP frame.
312 */
313
314static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
315 struct flowi4 *fl4, int type, int code)
316{
317 struct dst_entry *dst = &rt->dst;
318 struct inet_peer *peer;
319 bool rc = true;
320 int vif;
321
322 if (icmpv4_mask_allow(net, type, code))
323 goto out;
324
325 /* No rate limit on loopback */
326 if (dst->dev && (dst->dev->flags&IFF_LOOPBACK))
327 goto out;
328
329 vif = l3mdev_master_ifindex(dst->dev);
330 peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr, vif, 1);
331 rc = inet_peer_xrlim_allow(peer, net->ipv4.sysctl_icmp_ratelimit);
332 if (peer)
333 inet_putpeer(peer);
334out:
335 return rc;
336}
337
338/*
339 * Maintain the counters used in the SNMP statistics for outgoing ICMP
340 */
341void icmp_out_count(struct net *net, unsigned char type)
342{
343 ICMPMSGOUT_INC_STATS(net, type);
344 ICMP_INC_STATS(net, ICMP_MIB_OUTMSGS);
345}
346
347/*
348 * Checksum each fragment, and on the first include the headers and final
349 * checksum.
350 */
351static int icmp_glue_bits(void *from, char *to, int offset, int len, int odd,
352 struct sk_buff *skb)
353{
354 struct icmp_bxm *icmp_param = (struct icmp_bxm *)from;
355 __wsum csum;
356
357 csum = skb_copy_and_csum_bits(icmp_param->skb,
358 icmp_param->offset + offset,
359 to, len, 0);
360
361 skb->csum = csum_block_add(skb->csum, csum, odd);
362 if (icmp_pointers[icmp_param->data.icmph.type].error)
363 nf_ct_attach(skb, icmp_param->skb);
364 return 0;
365}
366
367static void icmp_push_reply(struct icmp_bxm *icmp_param,
368 struct flowi4 *fl4,
369 struct ipcm_cookie *ipc, struct rtable **rt)
370{
371 struct sock *sk;
372 struct sk_buff *skb;
373
374 sk = icmp_sk(dev_net((*rt)->dst.dev));
375 if (ip_append_data(sk, fl4, icmp_glue_bits, icmp_param,
376 icmp_param->data_len+icmp_param->head_len,
377 icmp_param->head_len,
378 ipc, rt, MSG_DONTWAIT) < 0) {
379 __ICMP_INC_STATS(sock_net(sk), ICMP_MIB_OUTERRORS);
380 ip_flush_pending_frames(sk);
381 } else if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) {
382 struct icmphdr *icmph = icmp_hdr(skb);
383 __wsum csum = 0;
384 struct sk_buff *skb1;
385
386 skb_queue_walk(&sk->sk_write_queue, skb1) {
387 csum = csum_add(csum, skb1->csum);
388 }
389 csum = csum_partial_copy_nocheck((void *)&icmp_param->data,
390 (char *)icmph,
391 icmp_param->head_len, csum);
392 icmph->checksum = csum_fold(csum);
393 skb->ip_summed = CHECKSUM_NONE;
394 ip_push_pending_frames(sk, fl4);
395 }
396}
397
398/*
399 * Driving logic for building and sending ICMP messages.
400 */
401
402static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
403{
404 struct ipcm_cookie ipc;
405 struct rtable *rt = skb_rtable(skb);
406 struct net *net = dev_net(rt->dst.dev);
407 struct flowi4 fl4;
408 struct sock *sk;
409 struct inet_sock *inet;
410 __be32 daddr, saddr;
411 u32 mark = IP4_REPLY_MARK(net, skb->mark);
412 int type = icmp_param->data.icmph.type;
413 int code = icmp_param->data.icmph.code;
414
415 if (ip_options_echo(net, &icmp_param->replyopts.opt.opt, skb))
416 return;
417
418 /* Needed by both icmp_global_allow and icmp_xmit_lock */
419 local_bh_disable();
420
421 /* global icmp_msgs_per_sec */
422 if (!icmpv4_global_allow(net, type, code))
423 goto out_bh_enable;
424
425 sk = icmp_xmit_lock(net);
426 if (!sk)
427 goto out_bh_enable;
428 inet = inet_sk(sk);
429
430 icmp_param->data.icmph.checksum = 0;
431
432 inet->tos = ip_hdr(skb)->tos;
433 sk->sk_mark = mark;
434 daddr = ipc.addr = ip_hdr(skb)->saddr;
435 saddr = fib_compute_spec_dst(skb);
436 ipc.opt = NULL;
437 ipc.tx_flags = 0;
438 ipc.ttl = 0;
439 ipc.tos = -1;
440
441 if (icmp_param->replyopts.opt.opt.optlen) {
442 ipc.opt = &icmp_param->replyopts.opt;
443 if (ipc.opt->opt.srr)
444 daddr = icmp_param->replyopts.opt.opt.faddr;
445 }
446 memset(&fl4, 0, sizeof(fl4));
447 fl4.daddr = daddr;
448 fl4.saddr = saddr;
449 fl4.flowi4_mark = mark;
450 fl4.flowi4_uid = sock_net_uid(net, NULL);
451 fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);
452 fl4.flowi4_proto = IPPROTO_ICMP;
453 fl4.flowi4_oif = l3mdev_master_ifindex(skb->dev);
454 security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
455 rt = ip_route_output_key(net, &fl4);
456 if (IS_ERR(rt))
457 goto out_unlock;
458 if (icmpv4_xrlim_allow(net, rt, &fl4, type, code))
459 icmp_push_reply(icmp_param, &fl4, &ipc, &rt);
460 ip_rt_put(rt);
461out_unlock:
462 icmp_xmit_unlock(sk);
463out_bh_enable:
464 local_bh_enable();
465}
466
467static struct rtable *icmp_route_lookup(struct net *net,
468 struct flowi4 *fl4,
469 struct sk_buff *skb_in,
470 const struct iphdr *iph,
471 __be32 saddr, u8 tos, u32 mark,
472 int type, int code,
473 struct icmp_bxm *param)
474{
475 struct rtable *rt, *rt2;
476 struct flowi4 fl4_dec;
477 int err;
478
479 memset(fl4, 0, sizeof(*fl4));
480 fl4->daddr = (param->replyopts.opt.opt.srr ?
481 param->replyopts.opt.opt.faddr : iph->saddr);
482 fl4->saddr = saddr;
483 fl4->flowi4_mark = mark;
484 fl4->flowi4_uid = sock_net_uid(net, NULL);
485 fl4->flowi4_tos = RT_TOS(tos);
486 fl4->flowi4_proto = IPPROTO_ICMP;
487 fl4->fl4_icmp_type = type;
488 fl4->fl4_icmp_code = code;
489 fl4->flowi4_oif = l3mdev_master_ifindex(skb_dst(skb_in)->dev);
490
491 security_skb_classify_flow(skb_in, flowi4_to_flowi(fl4));
492 rt = ip_route_output_key_hash(net, fl4, skb_in);
493 if (IS_ERR(rt))
494 return rt;
495
496 /* No need to clone since we're just using its address. */
497 rt2 = rt;
498
499 rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
500 flowi4_to_flowi(fl4), NULL, 0);
501 if (!IS_ERR(rt)) {
502 if (rt != rt2)
503 return rt;
504 } else if (PTR_ERR(rt) == -EPERM) {
505 rt = NULL;
506 } else
507 return rt;
508
509 err = xfrm_decode_session_reverse(skb_in, flowi4_to_flowi(&fl4_dec), AF_INET);
510 if (err)
511 goto relookup_failed;
512
513 if (inet_addr_type_dev_table(net, skb_dst(skb_in)->dev,
514 fl4_dec.saddr) == RTN_LOCAL) {
515 rt2 = __ip_route_output_key(net, &fl4_dec);
516 if (IS_ERR(rt2))
517 err = PTR_ERR(rt2);
518 } else {
519 struct flowi4 fl4_2 = {};
520 unsigned long orefdst;
521
522 fl4_2.daddr = fl4_dec.saddr;
523 rt2 = ip_route_output_key(net, &fl4_2);
524 if (IS_ERR(rt2)) {
525 err = PTR_ERR(rt2);
526 goto relookup_failed;
527 }
528 /* Ugh! */
529 orefdst = skb_in->_skb_refdst; /* save old refdst */
530 skb_dst_set(skb_in, NULL);
531 err = ip_route_input(skb_in, fl4_dec.daddr, fl4_dec.saddr,
532 RT_TOS(tos), rt2->dst.dev);
533
534 dst_release(&rt2->dst);
535 rt2 = skb_rtable(skb_in);
536 skb_in->_skb_refdst = orefdst; /* restore old refdst */
537 }
538
539 if (err)
540 goto relookup_failed;
541
542 rt2 = (struct rtable *) xfrm_lookup(net, &rt2->dst,
543 flowi4_to_flowi(&fl4_dec), NULL,
544 XFRM_LOOKUP_ICMP);
545 if (!IS_ERR(rt2)) {
546 dst_release(&rt->dst);
547 memcpy(fl4, &fl4_dec, sizeof(*fl4));
548 rt = rt2;
549 } else if (PTR_ERR(rt2) == -EPERM) {
550 if (rt)
551 dst_release(&rt->dst);
552 return rt2;
553 } else {
554 err = PTR_ERR(rt2);
555 goto relookup_failed;
556 }
557 return rt;
558
559relookup_failed:
560 if (rt)
561 return rt;
562 return ERR_PTR(err);
563}
564
565/*
566 * Send an ICMP message in response to a situation
567 *
568 * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header.
569 * MAY send more (we do).
570 * MUST NOT change this header information.
571 * MUST NOT reply to a multicast/broadcast IP address.
572 * MUST NOT reply to a multicast/broadcast MAC address.
573 * MUST reply to only the first fragment.
574 */
575
576void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
577{
578 struct iphdr *iph;
579 int room;
580 struct icmp_bxm icmp_param;
581 struct rtable *rt = skb_rtable(skb_in);
582 struct ipcm_cookie ipc;
583 struct flowi4 fl4;
584 __be32 saddr;
585 u8 tos;
586 u32 mark;
587 struct net *net;
588 struct sock *sk;
589
590 if (!rt)
591 goto out;
592 net = dev_net(rt->dst.dev);
593
594 /*
595 * Find the original header. It is expected to be valid, of course.
596 * Check this, icmp_send is called from the most obscure devices
597 * sometimes.
598 */
599 iph = ip_hdr(skb_in);
600
601 if ((u8 *)iph < skb_in->head ||
602 (skb_network_header(skb_in) + sizeof(*iph)) >
603 skb_tail_pointer(skb_in))
604 goto out;
605
606 /*
607 * No replies to physical multicast/broadcast
608 */
609 if (skb_in->pkt_type != PACKET_HOST)
610 goto out;
611
612 /*
613 * Now check at the protocol level
614 */
615 if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
616 goto out;
617
618 /*
619 * Only reply to fragment 0. We byte re-order the constant
620 * mask for efficiency.
621 */
622 if (iph->frag_off & htons(IP_OFFSET))
623 goto out;
624
625 /*
626 * If we send an ICMP error to an ICMP error a mess would result..
627 */
628 if (icmp_pointers[type].error) {
629 /*
630 * We are an error, check if we are replying to an
631 * ICMP error
632 */
633 if (iph->protocol == IPPROTO_ICMP) {
634 u8 _inner_type, *itp;
635
636 itp = skb_header_pointer(skb_in,
637 skb_network_header(skb_in) +
638 (iph->ihl << 2) +
639 offsetof(struct icmphdr,
640 type) -
641 skb_in->data,
642 sizeof(_inner_type),
643 &_inner_type);
644 if (!itp)
645 goto out;
646
647 /*
648 * Assume any unknown ICMP type is an error. This
649 * isn't specified by the RFC, but think about it..
650 */
651 if (*itp > NR_ICMP_TYPES ||
652 icmp_pointers[*itp].error)
653 goto out;
654 }
655 }
656
657 /* Needed by both icmp_global_allow and icmp_xmit_lock */
658 local_bh_disable();
659
660 /* Check global sysctl_icmp_msgs_per_sec ratelimit, unless
661 * incoming dev is loopback. If outgoing dev change to not be
662 * loopback, then peer ratelimit still work (in icmpv4_xrlim_allow)
663 */
664 if (!(skb_in->dev && (skb_in->dev->flags&IFF_LOOPBACK)) &&
665 !icmpv4_global_allow(net, type, code))
666 goto out_bh_enable;
667
668 sk = icmp_xmit_lock(net);
669 if (!sk)
670 goto out_bh_enable;
671
672 /*
673 * Construct source address and options.
674 */
675
676 saddr = iph->daddr;
677 if (!(rt->rt_flags & RTCF_LOCAL)) {
678 struct net_device *dev = NULL;
679
680 rcu_read_lock();
681 if (rt_is_input_route(rt) &&
682 net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr)
683 dev = dev_get_by_index_rcu(net, inet_iif(skb_in));
684
685 if (dev)
686 saddr = inet_select_addr(dev, 0, RT_SCOPE_LINK);
687 else
688 saddr = 0;
689 rcu_read_unlock();
690 }
691
692 tos = icmp_pointers[type].error ? ((iph->tos & IPTOS_TOS_MASK) |
693 IPTOS_PREC_INTERNETCONTROL) :
694 iph->tos;
695 mark = IP4_REPLY_MARK(net, skb_in->mark);
696
697 if (ip_options_echo(net, &icmp_param.replyopts.opt.opt, skb_in))
698 goto out_unlock;
699
700
701 /*
702 * Prepare data for ICMP header.
703 */
704
705 icmp_param.data.icmph.type = type;
706 icmp_param.data.icmph.code = code;
707 icmp_param.data.icmph.un.gateway = info;
708 icmp_param.data.icmph.checksum = 0;
709 icmp_param.skb = skb_in;
710 icmp_param.offset = skb_network_offset(skb_in);
711 inet_sk(sk)->tos = tos;
712 sk->sk_mark = mark;
713 ipc.addr = iph->saddr;
714 ipc.opt = &icmp_param.replyopts.opt;
715 ipc.tx_flags = 0;
716 ipc.ttl = 0;
717 ipc.tos = -1;
718
719 rt = icmp_route_lookup(net, &fl4, skb_in, iph, saddr, tos, mark,
720 type, code, &icmp_param);
721 if (IS_ERR(rt))
722 goto out_unlock;
723
724 /* peer icmp_ratelimit */
725 if (!icmpv4_xrlim_allow(net, rt, &fl4, type, code))
726 goto ende;
727
728 /* RFC says return as much as we can without exceeding 576 bytes. */
729
730 room = dst_mtu(&rt->dst);
731 if (room > 576)
732 room = 576;
733 room -= sizeof(struct iphdr) + icmp_param.replyopts.opt.opt.optlen;
734 room -= sizeof(struct icmphdr);
735
736 icmp_param.data_len = skb_in->len - icmp_param.offset;
737 if (icmp_param.data_len > room)
738 icmp_param.data_len = room;
739 icmp_param.head_len = sizeof(struct icmphdr);
740
741 icmp_push_reply(&icmp_param, &fl4, &ipc, &rt);
742ende:
743 ip_rt_put(rt);
744out_unlock:
745 icmp_xmit_unlock(sk);
746out_bh_enable:
747 local_bh_enable();
748out:;
749}
750EXPORT_SYMBOL(icmp_send);
751
752
753static void icmp_socket_deliver(struct sk_buff *skb, u32 info)
754{
755 const struct iphdr *iph = (const struct iphdr *) skb->data;
756 const struct net_protocol *ipprot;
757 int protocol = iph->protocol;
758
759 /* Checkin full IP header plus 8 bytes of protocol to
760 * avoid additional coding at protocol handlers.
761 */
762 if (!pskb_may_pull(skb, iph->ihl * 4 + 8)) {
763 __ICMP_INC_STATS(dev_net(skb->dev), ICMP_MIB_INERRORS);
764 return;
765 }
766
767 raw_icmp_error(skb, protocol, info);
768
769 ipprot = rcu_dereference(inet_protos[protocol]);
770 if (ipprot && ipprot->err_handler)
771 ipprot->err_handler(skb, info);
772}
773
774static bool icmp_tag_validation(int proto)
775{
776 bool ok;
777
778 rcu_read_lock();
779 ok = rcu_dereference(inet_protos[proto])->icmp_strict_tag_validation;
780 rcu_read_unlock();
781 return ok;
782}
783
784/*
785 * Handle ICMP_DEST_UNREACH, ICMP_TIME_EXCEEDED, ICMP_QUENCH, and
786 * ICMP_PARAMETERPROB.
787 */
788
789static bool icmp_unreach(struct sk_buff *skb)
790{
791 const struct iphdr *iph;
792 struct icmphdr *icmph;
793 struct net *net;
794 u32 info = 0;
795
796 net = dev_net(skb_dst(skb)->dev);
797
798 /*
799 * Incomplete header ?
800 * Only checks for the IP header, there should be an
801 * additional check for longer headers in upper levels.
802 */
803
804 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
805 goto out_err;
806
807 icmph = icmp_hdr(skb);
808 iph = (const struct iphdr *)skb->data;
809
810 if (iph->ihl < 5) /* Mangled header, drop. */
811 goto out_err;
812
813 switch (icmph->type) {
814 case ICMP_DEST_UNREACH:
815 switch (icmph->code & 15) {
816 case ICMP_NET_UNREACH:
817 case ICMP_HOST_UNREACH:
818 case ICMP_PROT_UNREACH:
819 case ICMP_PORT_UNREACH:
820 break;
821 case ICMP_FRAG_NEEDED:
822 /* for documentation of the ip_no_pmtu_disc
823 * values please see
824 * Documentation/networking/ip-sysctl.txt
825 */
826 switch (net->ipv4.sysctl_ip_no_pmtu_disc) {
827 default:
828 net_dbg_ratelimited("%pI4: fragmentation needed and DF set\n",
829 &iph->daddr);
830 break;
831 case 2:
832 goto out;
833 case 3:
834 if (!icmp_tag_validation(iph->protocol))
835 goto out;
836 /* fall through */
837 case 0:
838 info = ntohs(icmph->un.frag.mtu);
839 }
840 break;
841 case ICMP_SR_FAILED:
842 net_dbg_ratelimited("%pI4: Source Route Failed\n",
843 &iph->daddr);
844 break;
845 default:
846 break;
847 }
848 if (icmph->code > NR_ICMP_UNREACH)
849 goto out;
850 break;
851 case ICMP_PARAMETERPROB:
852 info = ntohl(icmph->un.gateway) >> 24;
853 break;
854 case ICMP_TIME_EXCEEDED:
855 __ICMP_INC_STATS(net, ICMP_MIB_INTIMEEXCDS);
856 if (icmph->code == ICMP_EXC_FRAGTIME)
857 goto out;
858 break;
859 }
860
861 /*
862 * Throw it at our lower layers
863 *
864 * RFC 1122: 3.2.2 MUST extract the protocol ID from the passed
865 * header.
866 * RFC 1122: 3.2.2.1 MUST pass ICMP unreach messages to the
867 * transport layer.
868 * RFC 1122: 3.2.2.2 MUST pass ICMP time expired messages to
869 * transport layer.
870 */
871
872 /*
873 * Check the other end isn't violating RFC 1122. Some routers send
874 * bogus responses to broadcast frames. If you see this message
875 * first check your netmask matches at both ends, if it does then
876 * get the other vendor to fix their kit.
877 */
878
879 if (!net->ipv4.sysctl_icmp_ignore_bogus_error_responses &&
880 inet_addr_type_dev_table(net, skb->dev, iph->daddr) == RTN_BROADCAST) {
881 net_warn_ratelimited("%pI4 sent an invalid ICMP type %u, code %u error to a broadcast: %pI4 on %s\n",
882 &ip_hdr(skb)->saddr,
883 icmph->type, icmph->code,
884 &iph->daddr, skb->dev->name);
885 goto out;
886 }
887
888 icmp_socket_deliver(skb, info);
889
890out:
891 return true;
892out_err:
893 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
894 return false;
895}
896
897
898/*
899 * Handle ICMP_REDIRECT.
900 */
901
902static bool icmp_redirect(struct sk_buff *skb)
903{
904 if (skb->len < sizeof(struct iphdr)) {
905 __ICMP_INC_STATS(dev_net(skb->dev), ICMP_MIB_INERRORS);
906 return false;
907 }
908
909 if (!pskb_may_pull(skb, sizeof(struct iphdr))) {
910 /* there aught to be a stat */
911 return false;
912 }
913
914 icmp_socket_deliver(skb, icmp_hdr(skb)->un.gateway);
915 return true;
916}
917
918/*
919 * Handle ICMP_ECHO ("ping") requests.
920 *
921 * RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo
922 * requests.
923 * RFC 1122: 3.2.2.6 Data received in the ICMP_ECHO request MUST be
924 * included in the reply.
925 * RFC 1812: 4.3.3.6 SHOULD have a config option for silently ignoring
926 * echo requests, MUST have default=NOT.
927 * See also WRT handling of options once they are done and working.
928 */
929
930static bool icmp_echo(struct sk_buff *skb)
931{
932 struct net *net;
933
934 net = dev_net(skb_dst(skb)->dev);
935 if (!net->ipv4.sysctl_icmp_echo_ignore_all) {
936 struct icmp_bxm icmp_param;
937
938 icmp_param.data.icmph = *icmp_hdr(skb);
939 icmp_param.data.icmph.type = ICMP_ECHOREPLY;
940 icmp_param.skb = skb;
941 icmp_param.offset = 0;
942 icmp_param.data_len = skb->len;
943 icmp_param.head_len = sizeof(struct icmphdr);
944 icmp_reply(&icmp_param, skb);
945 }
946 /* should there be an ICMP stat for ignored echos? */
947 return true;
948}
949
950/*
951 * Handle ICMP Timestamp requests.
952 * RFC 1122: 3.2.2.8 MAY implement ICMP timestamp requests.
953 * SHOULD be in the kernel for minimum random latency.
954 * MUST be accurate to a few minutes.
955 * MUST be updated at least at 15Hz.
956 */
957static bool icmp_timestamp(struct sk_buff *skb)
958{
959 struct icmp_bxm icmp_param;
960 /*
961 * Too short.
962 */
963 if (skb->len < 4)
964 goto out_err;
965
966 /*
967 * Fill in the current time as ms since midnight UT:
968 */
969 icmp_param.data.times[1] = inet_current_timestamp();
970 icmp_param.data.times[2] = icmp_param.data.times[1];
971
972 BUG_ON(skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4));
973
974 icmp_param.data.icmph = *icmp_hdr(skb);
975 icmp_param.data.icmph.type = ICMP_TIMESTAMPREPLY;
976 icmp_param.data.icmph.code = 0;
977 icmp_param.skb = skb;
978 icmp_param.offset = 0;
979 icmp_param.data_len = 0;
980 icmp_param.head_len = sizeof(struct icmphdr) + 12;
981 icmp_reply(&icmp_param, skb);
982 return true;
983
984out_err:
985 __ICMP_INC_STATS(dev_net(skb_dst(skb)->dev), ICMP_MIB_INERRORS);
986 return false;
987}
988
989static bool icmp_discard(struct sk_buff *skb)
990{
991 /* pretend it was a success */
992 return true;
993}
994
995/*
996 * Deal with incoming ICMP packets.
997 */
998int icmp_rcv(struct sk_buff *skb)
999{
1000 struct icmphdr *icmph;
1001 struct rtable *rt = skb_rtable(skb);
1002 struct net *net = dev_net(rt->dst.dev);
1003 bool success;
1004
1005 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1006 struct sec_path *sp = skb_sec_path(skb);
1007 int nh;
1008
1009 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
1010 XFRM_STATE_ICMP))
1011 goto drop;
1012
1013 if (!pskb_may_pull(skb, sizeof(*icmph) + sizeof(struct iphdr)))
1014 goto drop;
1015
1016 nh = skb_network_offset(skb);
1017 skb_set_network_header(skb, sizeof(*icmph));
1018
1019 if (!xfrm4_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
1020 goto drop;
1021
1022 skb_set_network_header(skb, nh);
1023 }
1024
1025 __ICMP_INC_STATS(net, ICMP_MIB_INMSGS);
1026
1027 if (skb_checksum_simple_validate(skb))
1028 goto csum_error;
1029
1030 if (!pskb_pull(skb, sizeof(*icmph)))
1031 goto error;
1032
1033 icmph = icmp_hdr(skb);
1034
1035 ICMPMSGIN_INC_STATS(net, icmph->type);
1036 /*
1037 * 18 is the highest 'known' ICMP type. Anything else is a mystery
1038 *
1039 * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
1040 * discarded.
1041 */
1042 if (icmph->type > NR_ICMP_TYPES)
1043 goto error;
1044
1045
1046 /*
1047 * Parse the ICMP message
1048 */
1049
1050 if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
1051 /*
1052 * RFC 1122: 3.2.2.6 An ICMP_ECHO to broadcast MAY be
1053 * silently ignored (we let user decide with a sysctl).
1054 * RFC 1122: 3.2.2.8 An ICMP_TIMESTAMP MAY be silently
1055 * discarded if to broadcast/multicast.
1056 */
1057 if ((icmph->type == ICMP_ECHO ||
1058 icmph->type == ICMP_TIMESTAMP) &&
1059 net->ipv4.sysctl_icmp_echo_ignore_broadcasts) {
1060 goto error;
1061 }
1062 if (icmph->type != ICMP_ECHO &&
1063 icmph->type != ICMP_TIMESTAMP &&
1064 icmph->type != ICMP_ADDRESS &&
1065 icmph->type != ICMP_ADDRESSREPLY) {
1066 goto error;
1067 }
1068 }
1069
1070 success = icmp_pointers[icmph->type].handler(skb);
1071
1072 if (success) {
1073 consume_skb(skb);
1074 return NET_RX_SUCCESS;
1075 }
1076
1077drop:
1078 kfree_skb(skb);
1079 return NET_RX_DROP;
1080csum_error:
1081 __ICMP_INC_STATS(net, ICMP_MIB_CSUMERRORS);
1082error:
1083 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
1084 goto drop;
1085}
1086
1087void icmp_err(struct sk_buff *skb, u32 info)
1088{
1089 struct iphdr *iph = (struct iphdr *)skb->data;
1090 int offset = iph->ihl<<2;
1091 struct icmphdr *icmph = (struct icmphdr *)(skb->data + offset);
1092 int type = icmp_hdr(skb)->type;
1093 int code = icmp_hdr(skb)->code;
1094 struct net *net = dev_net(skb->dev);
1095
1096 /*
1097 * Use ping_err to handle all icmp errors except those
1098 * triggered by ICMP_ECHOREPLY which sent from kernel.
1099 */
1100 if (icmph->type != ICMP_ECHOREPLY) {
1101 ping_err(skb, offset, info);
1102 return;
1103 }
1104
1105 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
1106 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_ICMP, 0);
1107 else if (type == ICMP_REDIRECT)
1108 ipv4_redirect(skb, net, 0, 0, IPPROTO_ICMP, 0);
1109}
1110
1111/*
1112 * This table is the definition of how we handle ICMP.
1113 */
1114static const struct icmp_control icmp_pointers[NR_ICMP_TYPES + 1] = {
1115 [ICMP_ECHOREPLY] = {
1116 .handler = ping_rcv,
1117 },
1118 [1] = {
1119 .handler = icmp_discard,
1120 .error = 1,
1121 },
1122 [2] = {
1123 .handler = icmp_discard,
1124 .error = 1,
1125 },
1126 [ICMP_DEST_UNREACH] = {
1127 .handler = icmp_unreach,
1128 .error = 1,
1129 },
1130 [ICMP_SOURCE_QUENCH] = {
1131 .handler = icmp_unreach,
1132 .error = 1,
1133 },
1134 [ICMP_REDIRECT] = {
1135 .handler = icmp_redirect,
1136 .error = 1,
1137 },
1138 [6] = {
1139 .handler = icmp_discard,
1140 .error = 1,
1141 },
1142 [7] = {
1143 .handler = icmp_discard,
1144 .error = 1,
1145 },
1146 [ICMP_ECHO] = {
1147 .handler = icmp_echo,
1148 },
1149 [9] = {
1150 .handler = icmp_discard,
1151 .error = 1,
1152 },
1153 [10] = {
1154 .handler = icmp_discard,
1155 .error = 1,
1156 },
1157 [ICMP_TIME_EXCEEDED] = {
1158 .handler = icmp_unreach,
1159 .error = 1,
1160 },
1161 [ICMP_PARAMETERPROB] = {
1162 .handler = icmp_unreach,
1163 .error = 1,
1164 },
1165 [ICMP_TIMESTAMP] = {
1166 .handler = icmp_timestamp,
1167 },
1168 [ICMP_TIMESTAMPREPLY] = {
1169 .handler = icmp_discard,
1170 },
1171 [ICMP_INFO_REQUEST] = {
1172 .handler = icmp_discard,
1173 },
1174 [ICMP_INFO_REPLY] = {
1175 .handler = icmp_discard,
1176 },
1177 [ICMP_ADDRESS] = {
1178 .handler = icmp_discard,
1179 },
1180 [ICMP_ADDRESSREPLY] = {
1181 .handler = icmp_discard,
1182 },
1183};
1184
1185static void __net_exit icmp_sk_exit(struct net *net)
1186{
1187 int i;
1188
1189 for_each_possible_cpu(i)
1190 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.icmp_sk, i));
1191 free_percpu(net->ipv4.icmp_sk);
1192 net->ipv4.icmp_sk = NULL;
1193}
1194
1195static int __net_init icmp_sk_init(struct net *net)
1196{
1197 int i, err;
1198
1199 net->ipv4.icmp_sk = alloc_percpu(struct sock *);
1200 if (!net->ipv4.icmp_sk)
1201 return -ENOMEM;
1202
1203 for_each_possible_cpu(i) {
1204 struct sock *sk;
1205
1206 err = inet_ctl_sock_create(&sk, PF_INET,
1207 SOCK_RAW, IPPROTO_ICMP, net);
1208 if (err < 0)
1209 goto fail;
1210
1211 *per_cpu_ptr(net->ipv4.icmp_sk, i) = sk;
1212
1213 /* Enough space for 2 64K ICMP packets, including
1214 * sk_buff/skb_shared_info struct overhead.
1215 */
1216 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
1217
1218 /*
1219 * Speedup sock_wfree()
1220 */
1221 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1222 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DONT;
1223 }
1224
1225 /* Control parameters for ECHO replies. */
1226 net->ipv4.sysctl_icmp_echo_ignore_all = 0;
1227 net->ipv4.sysctl_icmp_echo_ignore_broadcasts = 1;
1228
1229 /* Control parameter - ignore bogus broadcast responses? */
1230 net->ipv4.sysctl_icmp_ignore_bogus_error_responses = 1;
1231
1232 /*
1233 * Configurable global rate limit.
1234 *
1235 * ratelimit defines tokens/packet consumed for dst->rate_token
1236 * bucket ratemask defines which icmp types are ratelimited by
1237 * setting it's bit position.
1238 *
1239 * default:
1240 * dest unreachable (3), source quench (4),
1241 * time exceeded (11), parameter problem (12)
1242 */
1243
1244 net->ipv4.sysctl_icmp_ratelimit = 1 * HZ;
1245 net->ipv4.sysctl_icmp_ratemask = 0x1818;
1246 net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr = 0;
1247
1248 return 0;
1249
1250fail:
1251 for_each_possible_cpu(i)
1252 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.icmp_sk, i));
1253 free_percpu(net->ipv4.icmp_sk);
1254 return err;
1255}
1256
1257static struct pernet_operations __net_initdata icmp_sk_ops = {
1258 .init = icmp_sk_init,
1259 .exit = icmp_sk_exit,
1260};
1261
1262int __init icmp_init(void)
1263{
1264 return register_pernet_subsys(&icmp_sk_ops);
1265}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * NET3: Implementation of the ICMP protocol layer.
4 *
5 * Alan Cox, <alan@lxorguk.ukuu.org.uk>
6 *
7 * Some of the function names and the icmp unreach table for this
8 * module were derived from [icmp.c 1.0.11 06/02/93] by
9 * Ross Biro, Fred N. van Kempen, Mark Evans, Alan Cox, Gerhard Koerting.
10 * Other than that this module is a complete rewrite.
11 *
12 * Fixes:
13 * Clemens Fruhwirth : introduce global icmp rate limiting
14 * with icmp type masking ability instead
15 * of broken per type icmp timeouts.
16 * Mike Shaver : RFC1122 checks.
17 * Alan Cox : Multicast ping reply as self.
18 * Alan Cox : Fix atomicity lockup in ip_build_xmit
19 * call.
20 * Alan Cox : Added 216,128 byte paths to the MTU
21 * code.
22 * Martin Mares : RFC1812 checks.
23 * Martin Mares : Can be configured to follow redirects
24 * if acting as a router _without_ a
25 * routing protocol (RFC 1812).
26 * Martin Mares : Echo requests may be configured to
27 * be ignored (RFC 1812).
28 * Martin Mares : Limitation of ICMP error message
29 * transmit rate (RFC 1812).
30 * Martin Mares : TOS and Precedence set correctly
31 * (RFC 1812).
32 * Martin Mares : Now copying as much data from the
33 * original packet as we can without
34 * exceeding 576 bytes (RFC 1812).
35 * Willy Konynenberg : Transparent proxying support.
36 * Keith Owens : RFC1191 correction for 4.2BSD based
37 * path MTU bug.
38 * Thomas Quinot : ICMP Dest Unreach codes up to 15 are
39 * valid (RFC 1812).
40 * Andi Kleen : Check all packet lengths properly
41 * and moved all kfree_skb() up to
42 * icmp_rcv.
43 * Andi Kleen : Move the rate limit bookkeeping
44 * into the dest entry and use a token
45 * bucket filter (thanks to ANK). Make
46 * the rates sysctl configurable.
47 * Yu Tianli : Fixed two ugly bugs in icmp_send
48 * - IP option length was accounted wrongly
49 * - ICMP header length was not accounted
50 * at all.
51 * Tristan Greaves : Added sysctl option to ignore bogus
52 * broadcast responses from broken routers.
53 *
54 * To Fix:
55 *
56 * - Should use skb_pull() instead of all the manual checking.
57 * This would also greatly simply some upper layer error handlers. --AK
58 */
59
60#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
61
62#include <linux/module.h>
63#include <linux/types.h>
64#include <linux/jiffies.h>
65#include <linux/kernel.h>
66#include <linux/fcntl.h>
67#include <linux/socket.h>
68#include <linux/in.h>
69#include <linux/inet.h>
70#include <linux/inetdevice.h>
71#include <linux/netdevice.h>
72#include <linux/string.h>
73#include <linux/netfilter_ipv4.h>
74#include <linux/slab.h>
75#include <net/snmp.h>
76#include <net/ip.h>
77#include <net/route.h>
78#include <net/protocol.h>
79#include <net/icmp.h>
80#include <net/tcp.h>
81#include <net/udp.h>
82#include <net/raw.h>
83#include <net/ping.h>
84#include <linux/skbuff.h>
85#include <net/sock.h>
86#include <linux/errno.h>
87#include <linux/timer.h>
88#include <linux/init.h>
89#include <linux/uaccess.h>
90#include <net/checksum.h>
91#include <net/xfrm.h>
92#include <net/inet_common.h>
93#include <net/ip_fib.h>
94#include <net/l3mdev.h>
95#include <net/addrconf.h>
96#include <net/inet_dscp.h>
97#define CREATE_TRACE_POINTS
98#include <trace/events/icmp.h>
99
100/*
101 * Build xmit assembly blocks
102 */
103
104struct icmp_bxm {
105 struct sk_buff *skb;
106 int offset;
107 int data_len;
108
109 struct {
110 struct icmphdr icmph;
111 __be32 times[3];
112 } data;
113 int head_len;
114 struct ip_options_data replyopts;
115};
116
117/* An array of errno for error messages from dest unreach. */
118/* RFC 1122: 3.2.2.1 States that NET_UNREACH, HOST_UNREACH and SR_FAILED MUST be considered 'transient errs'. */
119
120const struct icmp_err icmp_err_convert[] = {
121 {
122 .errno = ENETUNREACH, /* ICMP_NET_UNREACH */
123 .fatal = 0,
124 },
125 {
126 .errno = EHOSTUNREACH, /* ICMP_HOST_UNREACH */
127 .fatal = 0,
128 },
129 {
130 .errno = ENOPROTOOPT /* ICMP_PROT_UNREACH */,
131 .fatal = 1,
132 },
133 {
134 .errno = ECONNREFUSED, /* ICMP_PORT_UNREACH */
135 .fatal = 1,
136 },
137 {
138 .errno = EMSGSIZE, /* ICMP_FRAG_NEEDED */
139 .fatal = 0,
140 },
141 {
142 .errno = EOPNOTSUPP, /* ICMP_SR_FAILED */
143 .fatal = 0,
144 },
145 {
146 .errno = ENETUNREACH, /* ICMP_NET_UNKNOWN */
147 .fatal = 1,
148 },
149 {
150 .errno = EHOSTDOWN, /* ICMP_HOST_UNKNOWN */
151 .fatal = 1,
152 },
153 {
154 .errno = ENONET, /* ICMP_HOST_ISOLATED */
155 .fatal = 1,
156 },
157 {
158 .errno = ENETUNREACH, /* ICMP_NET_ANO */
159 .fatal = 1,
160 },
161 {
162 .errno = EHOSTUNREACH, /* ICMP_HOST_ANO */
163 .fatal = 1,
164 },
165 {
166 .errno = ENETUNREACH, /* ICMP_NET_UNR_TOS */
167 .fatal = 0,
168 },
169 {
170 .errno = EHOSTUNREACH, /* ICMP_HOST_UNR_TOS */
171 .fatal = 0,
172 },
173 {
174 .errno = EHOSTUNREACH, /* ICMP_PKT_FILTERED */
175 .fatal = 1,
176 },
177 {
178 .errno = EHOSTUNREACH, /* ICMP_PREC_VIOLATION */
179 .fatal = 1,
180 },
181 {
182 .errno = EHOSTUNREACH, /* ICMP_PREC_CUTOFF */
183 .fatal = 1,
184 },
185};
186EXPORT_SYMBOL(icmp_err_convert);
187
188/*
189 * ICMP control array. This specifies what to do with each ICMP.
190 */
191
192struct icmp_control {
193 enum skb_drop_reason (*handler)(struct sk_buff *skb);
194 short error; /* This ICMP is classed as an error message */
195};
196
197static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1];
198
199static DEFINE_PER_CPU(struct sock *, ipv4_icmp_sk);
200
201/* Called with BH disabled */
202static inline struct sock *icmp_xmit_lock(struct net *net)
203{
204 struct sock *sk;
205
206 sk = this_cpu_read(ipv4_icmp_sk);
207
208 if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
209 /* This can happen if the output path signals a
210 * dst_link_failure() for an outgoing ICMP packet.
211 */
212 return NULL;
213 }
214 sock_net_set(sk, net);
215 return sk;
216}
217
218static inline void icmp_xmit_unlock(struct sock *sk)
219{
220 sock_net_set(sk, &init_net);
221 spin_unlock(&sk->sk_lock.slock);
222}
223
224/**
225 * icmp_global_allow - Are we allowed to send one more ICMP message ?
226 * @net: network namespace
227 *
228 * Uses a token bucket to limit our ICMP messages to ~sysctl_icmp_msgs_per_sec.
229 * Returns false if we reached the limit and can not send another packet.
230 * Works in tandem with icmp_global_consume().
231 */
232bool icmp_global_allow(struct net *net)
233{
234 u32 delta, now, oldstamp;
235 int incr, new, old;
236
237 /* Note: many cpus could find this condition true.
238 * Then later icmp_global_consume() could consume more credits,
239 * this is an acceptable race.
240 */
241 if (atomic_read(&net->ipv4.icmp_global_credit) > 0)
242 return true;
243
244 now = jiffies;
245 oldstamp = READ_ONCE(net->ipv4.icmp_global_stamp);
246 delta = min_t(u32, now - oldstamp, HZ);
247 if (delta < HZ / 50)
248 return false;
249
250 incr = READ_ONCE(net->ipv4.sysctl_icmp_msgs_per_sec) * delta / HZ;
251 if (!incr)
252 return false;
253
254 if (cmpxchg(&net->ipv4.icmp_global_stamp, oldstamp, now) == oldstamp) {
255 old = atomic_read(&net->ipv4.icmp_global_credit);
256 do {
257 new = min(old + incr, READ_ONCE(net->ipv4.sysctl_icmp_msgs_burst));
258 } while (!atomic_try_cmpxchg(&net->ipv4.icmp_global_credit, &old, new));
259 }
260 return true;
261}
262EXPORT_SYMBOL(icmp_global_allow);
263
264void icmp_global_consume(struct net *net)
265{
266 int credits = get_random_u32_below(3);
267
268 /* Note: this might make icmp_global.credit negative. */
269 if (credits)
270 atomic_sub(credits, &net->ipv4.icmp_global_credit);
271}
272EXPORT_SYMBOL(icmp_global_consume);
273
274static bool icmpv4_mask_allow(struct net *net, int type, int code)
275{
276 if (type > NR_ICMP_TYPES)
277 return true;
278
279 /* Don't limit PMTU discovery. */
280 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
281 return true;
282
283 /* Limit if icmp type is enabled in ratemask. */
284 if (!((1 << type) & READ_ONCE(net->ipv4.sysctl_icmp_ratemask)))
285 return true;
286
287 return false;
288}
289
290static bool icmpv4_global_allow(struct net *net, int type, int code,
291 bool *apply_ratelimit)
292{
293 if (icmpv4_mask_allow(net, type, code))
294 return true;
295
296 if (icmp_global_allow(net)) {
297 *apply_ratelimit = true;
298 return true;
299 }
300 __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITGLOBAL);
301 return false;
302}
303
304/*
305 * Send an ICMP frame.
306 */
307
308static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
309 struct flowi4 *fl4, int type, int code,
310 bool apply_ratelimit)
311{
312 struct dst_entry *dst = &rt->dst;
313 struct inet_peer *peer;
314 bool rc = true;
315
316 if (!apply_ratelimit)
317 return true;
318
319 /* No rate limit on loopback */
320 if (dst->dev && (dst->dev->flags&IFF_LOOPBACK))
321 goto out;
322
323 rcu_read_lock();
324 peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr,
325 l3mdev_master_ifindex_rcu(dst->dev));
326 rc = inet_peer_xrlim_allow(peer,
327 READ_ONCE(net->ipv4.sysctl_icmp_ratelimit));
328 rcu_read_unlock();
329out:
330 if (!rc)
331 __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITHOST);
332 else
333 icmp_global_consume(net);
334 return rc;
335}
336
337/*
338 * Maintain the counters used in the SNMP statistics for outgoing ICMP
339 */
340void icmp_out_count(struct net *net, unsigned char type)
341{
342 ICMPMSGOUT_INC_STATS(net, type);
343 ICMP_INC_STATS(net, ICMP_MIB_OUTMSGS);
344}
345
346/*
347 * Checksum each fragment, and on the first include the headers and final
348 * checksum.
349 */
350static int icmp_glue_bits(void *from, char *to, int offset, int len, int odd,
351 struct sk_buff *skb)
352{
353 struct icmp_bxm *icmp_param = from;
354 __wsum csum;
355
356 csum = skb_copy_and_csum_bits(icmp_param->skb,
357 icmp_param->offset + offset,
358 to, len);
359
360 skb->csum = csum_block_add(skb->csum, csum, odd);
361 if (icmp_pointers[icmp_param->data.icmph.type].error)
362 nf_ct_attach(skb, icmp_param->skb);
363 return 0;
364}
365
366static void icmp_push_reply(struct sock *sk,
367 struct icmp_bxm *icmp_param,
368 struct flowi4 *fl4,
369 struct ipcm_cookie *ipc, struct rtable **rt)
370{
371 struct sk_buff *skb;
372
373 if (ip_append_data(sk, fl4, icmp_glue_bits, icmp_param,
374 icmp_param->data_len+icmp_param->head_len,
375 icmp_param->head_len,
376 ipc, rt, MSG_DONTWAIT) < 0) {
377 __ICMP_INC_STATS(sock_net(sk), ICMP_MIB_OUTERRORS);
378 ip_flush_pending_frames(sk);
379 } else if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) {
380 struct icmphdr *icmph = icmp_hdr(skb);
381 __wsum csum;
382 struct sk_buff *skb1;
383
384 csum = csum_partial_copy_nocheck((void *)&icmp_param->data,
385 (char *)icmph,
386 icmp_param->head_len);
387 skb_queue_walk(&sk->sk_write_queue, skb1) {
388 csum = csum_add(csum, skb1->csum);
389 }
390 icmph->checksum = csum_fold(csum);
391 skb->ip_summed = CHECKSUM_NONE;
392 ip_push_pending_frames(sk, fl4);
393 }
394}
395
396/*
397 * Driving logic for building and sending ICMP messages.
398 */
399
400static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
401{
402 struct rtable *rt = skb_rtable(skb);
403 struct net *net = dev_net_rcu(rt->dst.dev);
404 bool apply_ratelimit = false;
405 struct ipcm_cookie ipc;
406 struct flowi4 fl4;
407 struct sock *sk;
408 struct inet_sock *inet;
409 __be32 daddr, saddr;
410 u32 mark = IP4_REPLY_MARK(net, skb->mark);
411 int type = icmp_param->data.icmph.type;
412 int code = icmp_param->data.icmph.code;
413
414 if (ip_options_echo(net, &icmp_param->replyopts.opt.opt, skb))
415 return;
416
417 /* Needed by both icmpv4_global_allow and icmp_xmit_lock */
418 local_bh_disable();
419
420 /* is global icmp_msgs_per_sec exhausted ? */
421 if (!icmpv4_global_allow(net, type, code, &apply_ratelimit))
422 goto out_bh_enable;
423
424 sk = icmp_xmit_lock(net);
425 if (!sk)
426 goto out_bh_enable;
427 inet = inet_sk(sk);
428
429 icmp_param->data.icmph.checksum = 0;
430
431 ipcm_init(&ipc);
432 inet->tos = ip_hdr(skb)->tos;
433 ipc.sockc.mark = mark;
434 daddr = ipc.addr = ip_hdr(skb)->saddr;
435 saddr = fib_compute_spec_dst(skb);
436
437 if (icmp_param->replyopts.opt.opt.optlen) {
438 ipc.opt = &icmp_param->replyopts.opt;
439 if (ipc.opt->opt.srr)
440 daddr = icmp_param->replyopts.opt.opt.faddr;
441 }
442 memset(&fl4, 0, sizeof(fl4));
443 fl4.daddr = daddr;
444 fl4.saddr = saddr;
445 fl4.flowi4_mark = mark;
446 fl4.flowi4_uid = sock_net_uid(net, NULL);
447 fl4.flowi4_tos = inet_dscp_to_dsfield(ip4h_dscp(ip_hdr(skb)));
448 fl4.flowi4_proto = IPPROTO_ICMP;
449 fl4.flowi4_oif = l3mdev_master_ifindex(skb->dev);
450 security_skb_classify_flow(skb, flowi4_to_flowi_common(&fl4));
451 rt = ip_route_output_key(net, &fl4);
452 if (IS_ERR(rt))
453 goto out_unlock;
454 if (icmpv4_xrlim_allow(net, rt, &fl4, type, code, apply_ratelimit))
455 icmp_push_reply(sk, icmp_param, &fl4, &ipc, &rt);
456 ip_rt_put(rt);
457out_unlock:
458 icmp_xmit_unlock(sk);
459out_bh_enable:
460 local_bh_enable();
461}
462
463/*
464 * The device used for looking up which routing table to use for sending an ICMP
465 * error is preferably the source whenever it is set, which should ensure the
466 * icmp error can be sent to the source host, else lookup using the routing
467 * table of the destination device, else use the main routing table (index 0).
468 */
469static struct net_device *icmp_get_route_lookup_dev(struct sk_buff *skb)
470{
471 struct net_device *route_lookup_dev = NULL;
472
473 if (skb->dev)
474 route_lookup_dev = skb->dev;
475 else if (skb_dst(skb))
476 route_lookup_dev = skb_dst(skb)->dev;
477 return route_lookup_dev;
478}
479
480static struct rtable *icmp_route_lookup(struct net *net, struct flowi4 *fl4,
481 struct sk_buff *skb_in,
482 const struct iphdr *iph, __be32 saddr,
483 dscp_t dscp, u32 mark, int type,
484 int code, struct icmp_bxm *param)
485{
486 struct net_device *route_lookup_dev;
487 struct dst_entry *dst, *dst2;
488 struct rtable *rt, *rt2;
489 struct flowi4 fl4_dec;
490 int err;
491
492 memset(fl4, 0, sizeof(*fl4));
493 fl4->daddr = (param->replyopts.opt.opt.srr ?
494 param->replyopts.opt.opt.faddr : iph->saddr);
495 fl4->saddr = saddr;
496 fl4->flowi4_mark = mark;
497 fl4->flowi4_uid = sock_net_uid(net, NULL);
498 fl4->flowi4_tos = inet_dscp_to_dsfield(dscp);
499 fl4->flowi4_proto = IPPROTO_ICMP;
500 fl4->fl4_icmp_type = type;
501 fl4->fl4_icmp_code = code;
502 route_lookup_dev = icmp_get_route_lookup_dev(skb_in);
503 fl4->flowi4_oif = l3mdev_master_ifindex(route_lookup_dev);
504
505 security_skb_classify_flow(skb_in, flowi4_to_flowi_common(fl4));
506 rt = ip_route_output_key_hash(net, fl4, skb_in);
507 if (IS_ERR(rt))
508 return rt;
509
510 /* No need to clone since we're just using its address. */
511 rt2 = rt;
512
513 dst = xfrm_lookup(net, &rt->dst,
514 flowi4_to_flowi(fl4), NULL, 0);
515 rt = dst_rtable(dst);
516 if (!IS_ERR(dst)) {
517 if (rt != rt2)
518 return rt;
519 if (inet_addr_type_dev_table(net, route_lookup_dev,
520 fl4->daddr) == RTN_LOCAL)
521 return rt;
522 } else if (PTR_ERR(dst) == -EPERM) {
523 rt = NULL;
524 } else {
525 return rt;
526 }
527 err = xfrm_decode_session_reverse(net, skb_in, flowi4_to_flowi(&fl4_dec), AF_INET);
528 if (err)
529 goto relookup_failed;
530
531 if (inet_addr_type_dev_table(net, route_lookup_dev,
532 fl4_dec.saddr) == RTN_LOCAL) {
533 rt2 = __ip_route_output_key(net, &fl4_dec);
534 if (IS_ERR(rt2))
535 err = PTR_ERR(rt2);
536 } else {
537 struct flowi4 fl4_2 = {};
538 unsigned long orefdst;
539
540 fl4_2.daddr = fl4_dec.saddr;
541 rt2 = ip_route_output_key(net, &fl4_2);
542 if (IS_ERR(rt2)) {
543 err = PTR_ERR(rt2);
544 goto relookup_failed;
545 }
546 /* Ugh! */
547 orefdst = skb_in->_skb_refdst; /* save old refdst */
548 skb_dst_set(skb_in, NULL);
549 err = ip_route_input(skb_in, fl4_dec.daddr, fl4_dec.saddr,
550 dscp, rt2->dst.dev) ? -EINVAL : 0;
551
552 dst_release(&rt2->dst);
553 rt2 = skb_rtable(skb_in);
554 skb_in->_skb_refdst = orefdst; /* restore old refdst */
555 }
556
557 if (err)
558 goto relookup_failed;
559
560 dst2 = xfrm_lookup(net, &rt2->dst, flowi4_to_flowi(&fl4_dec), NULL,
561 XFRM_LOOKUP_ICMP);
562 rt2 = dst_rtable(dst2);
563 if (!IS_ERR(dst2)) {
564 dst_release(&rt->dst);
565 memcpy(fl4, &fl4_dec, sizeof(*fl4));
566 rt = rt2;
567 } else if (PTR_ERR(dst2) == -EPERM) {
568 if (rt)
569 dst_release(&rt->dst);
570 return rt2;
571 } else {
572 err = PTR_ERR(dst2);
573 goto relookup_failed;
574 }
575 return rt;
576
577relookup_failed:
578 if (rt)
579 return rt;
580 return ERR_PTR(err);
581}
582
583/*
584 * Send an ICMP message in response to a situation
585 *
586 * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header.
587 * MAY send more (we do).
588 * MUST NOT change this header information.
589 * MUST NOT reply to a multicast/broadcast IP address.
590 * MUST NOT reply to a multicast/broadcast MAC address.
591 * MUST reply to only the first fragment.
592 */
593
594void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info,
595 const struct ip_options *opt)
596{
597 struct iphdr *iph;
598 int room;
599 struct icmp_bxm icmp_param;
600 struct rtable *rt = skb_rtable(skb_in);
601 bool apply_ratelimit = false;
602 struct ipcm_cookie ipc;
603 struct flowi4 fl4;
604 __be32 saddr;
605 u8 tos;
606 u32 mark;
607 struct net *net;
608 struct sock *sk;
609
610 if (!rt)
611 return;
612
613 rcu_read_lock();
614
615 if (rt->dst.dev)
616 net = dev_net_rcu(rt->dst.dev);
617 else if (skb_in->dev)
618 net = dev_net_rcu(skb_in->dev);
619 else
620 goto out;
621
622 /*
623 * Find the original header. It is expected to be valid, of course.
624 * Check this, icmp_send is called from the most obscure devices
625 * sometimes.
626 */
627 iph = ip_hdr(skb_in);
628
629 if ((u8 *)iph < skb_in->head ||
630 (skb_network_header(skb_in) + sizeof(*iph)) >
631 skb_tail_pointer(skb_in))
632 goto out;
633
634 /*
635 * No replies to physical multicast/broadcast
636 */
637 if (skb_in->pkt_type != PACKET_HOST)
638 goto out;
639
640 /*
641 * Now check at the protocol level
642 */
643 if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
644 goto out;
645
646 /*
647 * Only reply to fragment 0. We byte re-order the constant
648 * mask for efficiency.
649 */
650 if (iph->frag_off & htons(IP_OFFSET))
651 goto out;
652
653 /*
654 * If we send an ICMP error to an ICMP error a mess would result..
655 */
656 if (icmp_pointers[type].error) {
657 /*
658 * We are an error, check if we are replying to an
659 * ICMP error
660 */
661 if (iph->protocol == IPPROTO_ICMP) {
662 u8 _inner_type, *itp;
663
664 itp = skb_header_pointer(skb_in,
665 skb_network_header(skb_in) +
666 (iph->ihl << 2) +
667 offsetof(struct icmphdr,
668 type) -
669 skb_in->data,
670 sizeof(_inner_type),
671 &_inner_type);
672 if (!itp)
673 goto out;
674
675 /*
676 * Assume any unknown ICMP type is an error. This
677 * isn't specified by the RFC, but think about it..
678 */
679 if (*itp > NR_ICMP_TYPES ||
680 icmp_pointers[*itp].error)
681 goto out;
682 }
683 }
684
685 /* Needed by both icmpv4_global_allow and icmp_xmit_lock */
686 local_bh_disable();
687
688 /* Check global sysctl_icmp_msgs_per_sec ratelimit, unless
689 * incoming dev is loopback. If outgoing dev change to not be
690 * loopback, then peer ratelimit still work (in icmpv4_xrlim_allow)
691 */
692 if (!(skb_in->dev && (skb_in->dev->flags&IFF_LOOPBACK)) &&
693 !icmpv4_global_allow(net, type, code, &apply_ratelimit))
694 goto out_bh_enable;
695
696 sk = icmp_xmit_lock(net);
697 if (!sk)
698 goto out_bh_enable;
699
700 /*
701 * Construct source address and options.
702 */
703
704 saddr = iph->daddr;
705 if (!(rt->rt_flags & RTCF_LOCAL)) {
706 struct net_device *dev = NULL;
707
708 rcu_read_lock();
709 if (rt_is_input_route(rt) &&
710 READ_ONCE(net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr))
711 dev = dev_get_by_index_rcu(net, inet_iif(skb_in));
712
713 if (dev)
714 saddr = inet_select_addr(dev, iph->saddr,
715 RT_SCOPE_LINK);
716 else
717 saddr = 0;
718 rcu_read_unlock();
719 }
720
721 tos = icmp_pointers[type].error ? (RT_TOS(iph->tos) |
722 IPTOS_PREC_INTERNETCONTROL) :
723 iph->tos;
724 mark = IP4_REPLY_MARK(net, skb_in->mark);
725
726 if (__ip_options_echo(net, &icmp_param.replyopts.opt.opt, skb_in, opt))
727 goto out_unlock;
728
729
730 /*
731 * Prepare data for ICMP header.
732 */
733
734 icmp_param.data.icmph.type = type;
735 icmp_param.data.icmph.code = code;
736 icmp_param.data.icmph.un.gateway = info;
737 icmp_param.data.icmph.checksum = 0;
738 icmp_param.skb = skb_in;
739 icmp_param.offset = skb_network_offset(skb_in);
740 inet_sk(sk)->tos = tos;
741 ipcm_init(&ipc);
742 ipc.addr = iph->saddr;
743 ipc.opt = &icmp_param.replyopts.opt;
744 ipc.sockc.mark = mark;
745
746 rt = icmp_route_lookup(net, &fl4, skb_in, iph, saddr,
747 inet_dsfield_to_dscp(tos), mark, type, code,
748 &icmp_param);
749 if (IS_ERR(rt))
750 goto out_unlock;
751
752 /* peer icmp_ratelimit */
753 if (!icmpv4_xrlim_allow(net, rt, &fl4, type, code, apply_ratelimit))
754 goto ende;
755
756 /* RFC says return as much as we can without exceeding 576 bytes. */
757
758 room = dst_mtu(&rt->dst);
759 if (room > 576)
760 room = 576;
761 room -= sizeof(struct iphdr) + icmp_param.replyopts.opt.opt.optlen;
762 room -= sizeof(struct icmphdr);
763 /* Guard against tiny mtu. We need to include at least one
764 * IP network header for this message to make any sense.
765 */
766 if (room <= (int)sizeof(struct iphdr))
767 goto ende;
768
769 icmp_param.data_len = skb_in->len - icmp_param.offset;
770 if (icmp_param.data_len > room)
771 icmp_param.data_len = room;
772 icmp_param.head_len = sizeof(struct icmphdr);
773
774 /* if we don't have a source address at this point, fall back to the
775 * dummy address instead of sending out a packet with a source address
776 * of 0.0.0.0
777 */
778 if (!fl4.saddr)
779 fl4.saddr = htonl(INADDR_DUMMY);
780
781 trace_icmp_send(skb_in, type, code);
782
783 icmp_push_reply(sk, &icmp_param, &fl4, &ipc, &rt);
784ende:
785 ip_rt_put(rt);
786out_unlock:
787 icmp_xmit_unlock(sk);
788out_bh_enable:
789 local_bh_enable();
790out:
791 rcu_read_unlock();
792}
793EXPORT_SYMBOL(__icmp_send);
794
795#if IS_ENABLED(CONFIG_NF_NAT)
796#include <net/netfilter/nf_conntrack.h>
797void icmp_ndo_send(struct sk_buff *skb_in, int type, int code, __be32 info)
798{
799 struct sk_buff *cloned_skb = NULL;
800 struct ip_options opts = { 0 };
801 enum ip_conntrack_info ctinfo;
802 struct nf_conn *ct;
803 __be32 orig_ip;
804
805 ct = nf_ct_get(skb_in, &ctinfo);
806 if (!ct || !(ct->status & IPS_SRC_NAT)) {
807 __icmp_send(skb_in, type, code, info, &opts);
808 return;
809 }
810
811 if (skb_shared(skb_in))
812 skb_in = cloned_skb = skb_clone(skb_in, GFP_ATOMIC);
813
814 if (unlikely(!skb_in || skb_network_header(skb_in) < skb_in->head ||
815 (skb_network_header(skb_in) + sizeof(struct iphdr)) >
816 skb_tail_pointer(skb_in) || skb_ensure_writable(skb_in,
817 skb_network_offset(skb_in) + sizeof(struct iphdr))))
818 goto out;
819
820 orig_ip = ip_hdr(skb_in)->saddr;
821 ip_hdr(skb_in)->saddr = ct->tuplehash[0].tuple.src.u3.ip;
822 __icmp_send(skb_in, type, code, info, &opts);
823 ip_hdr(skb_in)->saddr = orig_ip;
824out:
825 consume_skb(cloned_skb);
826}
827EXPORT_SYMBOL(icmp_ndo_send);
828#endif
829
830static void icmp_socket_deliver(struct sk_buff *skb, u32 info)
831{
832 const struct iphdr *iph = (const struct iphdr *)skb->data;
833 const struct net_protocol *ipprot;
834 int protocol = iph->protocol;
835
836 /* Checkin full IP header plus 8 bytes of protocol to
837 * avoid additional coding at protocol handlers.
838 */
839 if (!pskb_may_pull(skb, iph->ihl * 4 + 8)) {
840 __ICMP_INC_STATS(dev_net_rcu(skb->dev), ICMP_MIB_INERRORS);
841 return;
842 }
843
844 raw_icmp_error(skb, protocol, info);
845
846 ipprot = rcu_dereference(inet_protos[protocol]);
847 if (ipprot && ipprot->err_handler)
848 ipprot->err_handler(skb, info);
849}
850
851static bool icmp_tag_validation(int proto)
852{
853 bool ok;
854
855 rcu_read_lock();
856 ok = rcu_dereference(inet_protos[proto])->icmp_strict_tag_validation;
857 rcu_read_unlock();
858 return ok;
859}
860
861/*
862 * Handle ICMP_DEST_UNREACH, ICMP_TIME_EXCEEDED, ICMP_QUENCH, and
863 * ICMP_PARAMETERPROB.
864 */
865
866static enum skb_drop_reason icmp_unreach(struct sk_buff *skb)
867{
868 enum skb_drop_reason reason = SKB_NOT_DROPPED_YET;
869 const struct iphdr *iph;
870 struct icmphdr *icmph;
871 struct net *net;
872 u32 info = 0;
873
874 net = dev_net_rcu(skb_dst(skb)->dev);
875
876 /*
877 * Incomplete header ?
878 * Only checks for the IP header, there should be an
879 * additional check for longer headers in upper levels.
880 */
881
882 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
883 goto out_err;
884
885 icmph = icmp_hdr(skb);
886 iph = (const struct iphdr *)skb->data;
887
888 if (iph->ihl < 5) { /* Mangled header, drop. */
889 reason = SKB_DROP_REASON_IP_INHDR;
890 goto out_err;
891 }
892
893 switch (icmph->type) {
894 case ICMP_DEST_UNREACH:
895 switch (icmph->code & 15) {
896 case ICMP_NET_UNREACH:
897 case ICMP_HOST_UNREACH:
898 case ICMP_PROT_UNREACH:
899 case ICMP_PORT_UNREACH:
900 break;
901 case ICMP_FRAG_NEEDED:
902 /* for documentation of the ip_no_pmtu_disc
903 * values please see
904 * Documentation/networking/ip-sysctl.rst
905 */
906 switch (READ_ONCE(net->ipv4.sysctl_ip_no_pmtu_disc)) {
907 default:
908 net_dbg_ratelimited("%pI4: fragmentation needed and DF set\n",
909 &iph->daddr);
910 break;
911 case 2:
912 goto out;
913 case 3:
914 if (!icmp_tag_validation(iph->protocol))
915 goto out;
916 fallthrough;
917 case 0:
918 info = ntohs(icmph->un.frag.mtu);
919 }
920 break;
921 case ICMP_SR_FAILED:
922 net_dbg_ratelimited("%pI4: Source Route Failed\n",
923 &iph->daddr);
924 break;
925 default:
926 break;
927 }
928 if (icmph->code > NR_ICMP_UNREACH)
929 goto out;
930 break;
931 case ICMP_PARAMETERPROB:
932 info = ntohl(icmph->un.gateway) >> 24;
933 break;
934 case ICMP_TIME_EXCEEDED:
935 __ICMP_INC_STATS(net, ICMP_MIB_INTIMEEXCDS);
936 if (icmph->code == ICMP_EXC_FRAGTIME)
937 goto out;
938 break;
939 }
940
941 /*
942 * Throw it at our lower layers
943 *
944 * RFC 1122: 3.2.2 MUST extract the protocol ID from the passed
945 * header.
946 * RFC 1122: 3.2.2.1 MUST pass ICMP unreach messages to the
947 * transport layer.
948 * RFC 1122: 3.2.2.2 MUST pass ICMP time expired messages to
949 * transport layer.
950 */
951
952 /*
953 * Check the other end isn't violating RFC 1122. Some routers send
954 * bogus responses to broadcast frames. If you see this message
955 * first check your netmask matches at both ends, if it does then
956 * get the other vendor to fix their kit.
957 */
958
959 if (!READ_ONCE(net->ipv4.sysctl_icmp_ignore_bogus_error_responses) &&
960 inet_addr_type_dev_table(net, skb->dev, iph->daddr) == RTN_BROADCAST) {
961 net_warn_ratelimited("%pI4 sent an invalid ICMP type %u, code %u error to a broadcast: %pI4 on %s\n",
962 &ip_hdr(skb)->saddr,
963 icmph->type, icmph->code,
964 &iph->daddr, skb->dev->name);
965 goto out;
966 }
967
968 icmp_socket_deliver(skb, info);
969
970out:
971 return reason;
972out_err:
973 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
974 return reason ?: SKB_DROP_REASON_NOT_SPECIFIED;
975}
976
977
978/*
979 * Handle ICMP_REDIRECT.
980 */
981
982static enum skb_drop_reason icmp_redirect(struct sk_buff *skb)
983{
984 if (skb->len < sizeof(struct iphdr)) {
985 __ICMP_INC_STATS(dev_net_rcu(skb->dev), ICMP_MIB_INERRORS);
986 return SKB_DROP_REASON_PKT_TOO_SMALL;
987 }
988
989 if (!pskb_may_pull(skb, sizeof(struct iphdr))) {
990 /* there aught to be a stat */
991 return SKB_DROP_REASON_NOMEM;
992 }
993
994 icmp_socket_deliver(skb, ntohl(icmp_hdr(skb)->un.gateway));
995 return SKB_NOT_DROPPED_YET;
996}
997
998/*
999 * Handle ICMP_ECHO ("ping") and ICMP_EXT_ECHO ("PROBE") requests.
1000 *
1001 * RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo
1002 * requests.
1003 * RFC 1122: 3.2.2.6 Data received in the ICMP_ECHO request MUST be
1004 * included in the reply.
1005 * RFC 1812: 4.3.3.6 SHOULD have a config option for silently ignoring
1006 * echo requests, MUST have default=NOT.
1007 * RFC 8335: 8 MUST have a config option to enable/disable ICMP
1008 * Extended Echo Functionality, MUST be disabled by default
1009 * See also WRT handling of options once they are done and working.
1010 */
1011
1012static enum skb_drop_reason icmp_echo(struct sk_buff *skb)
1013{
1014 struct icmp_bxm icmp_param;
1015 struct net *net;
1016
1017 net = dev_net_rcu(skb_dst(skb)->dev);
1018 /* should there be an ICMP stat for ignored echos? */
1019 if (READ_ONCE(net->ipv4.sysctl_icmp_echo_ignore_all))
1020 return SKB_NOT_DROPPED_YET;
1021
1022 icmp_param.data.icmph = *icmp_hdr(skb);
1023 icmp_param.skb = skb;
1024 icmp_param.offset = 0;
1025 icmp_param.data_len = skb->len;
1026 icmp_param.head_len = sizeof(struct icmphdr);
1027
1028 if (icmp_param.data.icmph.type == ICMP_ECHO)
1029 icmp_param.data.icmph.type = ICMP_ECHOREPLY;
1030 else if (!icmp_build_probe(skb, &icmp_param.data.icmph))
1031 return SKB_NOT_DROPPED_YET;
1032
1033 icmp_reply(&icmp_param, skb);
1034 return SKB_NOT_DROPPED_YET;
1035}
1036
1037/* Helper for icmp_echo and icmpv6_echo_reply.
1038 * Searches for net_device that matches PROBE interface identifier
1039 * and builds PROBE reply message in icmphdr.
1040 *
1041 * Returns false if PROBE responses are disabled via sysctl
1042 */
1043
1044bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr)
1045{
1046 struct net *net = dev_net_rcu(skb->dev);
1047 struct icmp_ext_hdr *ext_hdr, _ext_hdr;
1048 struct icmp_ext_echo_iio *iio, _iio;
1049 struct inet6_dev *in6_dev;
1050 struct in_device *in_dev;
1051 struct net_device *dev;
1052 char buff[IFNAMSIZ];
1053 u16 ident_len;
1054 u8 status;
1055
1056 if (!READ_ONCE(net->ipv4.sysctl_icmp_echo_enable_probe))
1057 return false;
1058
1059 /* We currently only support probing interfaces on the proxy node
1060 * Check to ensure L-bit is set
1061 */
1062 if (!(ntohs(icmphdr->un.echo.sequence) & 1))
1063 return false;
1064 /* Clear status bits in reply message */
1065 icmphdr->un.echo.sequence &= htons(0xFF00);
1066 if (icmphdr->type == ICMP_EXT_ECHO)
1067 icmphdr->type = ICMP_EXT_ECHOREPLY;
1068 else
1069 icmphdr->type = ICMPV6_EXT_ECHO_REPLY;
1070 ext_hdr = skb_header_pointer(skb, 0, sizeof(_ext_hdr), &_ext_hdr);
1071 /* Size of iio is class_type dependent.
1072 * Only check header here and assign length based on ctype in the switch statement
1073 */
1074 iio = skb_header_pointer(skb, sizeof(_ext_hdr), sizeof(iio->extobj_hdr), &_iio);
1075 if (!ext_hdr || !iio)
1076 goto send_mal_query;
1077 if (ntohs(iio->extobj_hdr.length) <= sizeof(iio->extobj_hdr) ||
1078 ntohs(iio->extobj_hdr.length) > sizeof(_iio))
1079 goto send_mal_query;
1080 ident_len = ntohs(iio->extobj_hdr.length) - sizeof(iio->extobj_hdr);
1081 iio = skb_header_pointer(skb, sizeof(_ext_hdr),
1082 sizeof(iio->extobj_hdr) + ident_len, &_iio);
1083 if (!iio)
1084 goto send_mal_query;
1085
1086 status = 0;
1087 dev = NULL;
1088 switch (iio->extobj_hdr.class_type) {
1089 case ICMP_EXT_ECHO_CTYPE_NAME:
1090 if (ident_len >= IFNAMSIZ)
1091 goto send_mal_query;
1092 memset(buff, 0, sizeof(buff));
1093 memcpy(buff, &iio->ident.name, ident_len);
1094 dev = dev_get_by_name(net, buff);
1095 break;
1096 case ICMP_EXT_ECHO_CTYPE_INDEX:
1097 if (ident_len != sizeof(iio->ident.ifindex))
1098 goto send_mal_query;
1099 dev = dev_get_by_index(net, ntohl(iio->ident.ifindex));
1100 break;
1101 case ICMP_EXT_ECHO_CTYPE_ADDR:
1102 if (ident_len < sizeof(iio->ident.addr.ctype3_hdr) ||
1103 ident_len != sizeof(iio->ident.addr.ctype3_hdr) +
1104 iio->ident.addr.ctype3_hdr.addrlen)
1105 goto send_mal_query;
1106 switch (ntohs(iio->ident.addr.ctype3_hdr.afi)) {
1107 case ICMP_AFI_IP:
1108 if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in_addr))
1109 goto send_mal_query;
1110 dev = ip_dev_find(net, iio->ident.addr.ip_addr.ipv4_addr);
1111 break;
1112#if IS_ENABLED(CONFIG_IPV6)
1113 case ICMP_AFI_IP6:
1114 if (iio->ident.addr.ctype3_hdr.addrlen != sizeof(struct in6_addr))
1115 goto send_mal_query;
1116 dev = ipv6_stub->ipv6_dev_find(net, &iio->ident.addr.ip_addr.ipv6_addr, dev);
1117 dev_hold(dev);
1118 break;
1119#endif
1120 default:
1121 goto send_mal_query;
1122 }
1123 break;
1124 default:
1125 goto send_mal_query;
1126 }
1127 if (!dev) {
1128 icmphdr->code = ICMP_EXT_CODE_NO_IF;
1129 return true;
1130 }
1131 /* Fill bits in reply message */
1132 if (dev->flags & IFF_UP)
1133 status |= ICMP_EXT_ECHOREPLY_ACTIVE;
1134
1135 in_dev = __in_dev_get_rcu(dev);
1136 if (in_dev && rcu_access_pointer(in_dev->ifa_list))
1137 status |= ICMP_EXT_ECHOREPLY_IPV4;
1138
1139 in6_dev = __in6_dev_get(dev);
1140 if (in6_dev && !list_empty(&in6_dev->addr_list))
1141 status |= ICMP_EXT_ECHOREPLY_IPV6;
1142
1143 dev_put(dev);
1144 icmphdr->un.echo.sequence |= htons(status);
1145 return true;
1146send_mal_query:
1147 icmphdr->code = ICMP_EXT_CODE_MAL_QUERY;
1148 return true;
1149}
1150EXPORT_SYMBOL_GPL(icmp_build_probe);
1151
1152/*
1153 * Handle ICMP Timestamp requests.
1154 * RFC 1122: 3.2.2.8 MAY implement ICMP timestamp requests.
1155 * SHOULD be in the kernel for minimum random latency.
1156 * MUST be accurate to a few minutes.
1157 * MUST be updated at least at 15Hz.
1158 */
1159static enum skb_drop_reason icmp_timestamp(struct sk_buff *skb)
1160{
1161 struct icmp_bxm icmp_param;
1162 /*
1163 * Too short.
1164 */
1165 if (skb->len < 4)
1166 goto out_err;
1167
1168 /*
1169 * Fill in the current time as ms since midnight UT:
1170 */
1171 icmp_param.data.times[1] = inet_current_timestamp();
1172 icmp_param.data.times[2] = icmp_param.data.times[1];
1173
1174 BUG_ON(skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4));
1175
1176 icmp_param.data.icmph = *icmp_hdr(skb);
1177 icmp_param.data.icmph.type = ICMP_TIMESTAMPREPLY;
1178 icmp_param.data.icmph.code = 0;
1179 icmp_param.skb = skb;
1180 icmp_param.offset = 0;
1181 icmp_param.data_len = 0;
1182 icmp_param.head_len = sizeof(struct icmphdr) + 12;
1183 icmp_reply(&icmp_param, skb);
1184 return SKB_NOT_DROPPED_YET;
1185
1186out_err:
1187 __ICMP_INC_STATS(dev_net_rcu(skb_dst(skb)->dev), ICMP_MIB_INERRORS);
1188 return SKB_DROP_REASON_PKT_TOO_SMALL;
1189}
1190
1191static enum skb_drop_reason icmp_discard(struct sk_buff *skb)
1192{
1193 /* pretend it was a success */
1194 return SKB_NOT_DROPPED_YET;
1195}
1196
1197/*
1198 * Deal with incoming ICMP packets.
1199 */
1200int icmp_rcv(struct sk_buff *skb)
1201{
1202 enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
1203 struct rtable *rt = skb_rtable(skb);
1204 struct net *net = dev_net_rcu(rt->dst.dev);
1205 struct icmphdr *icmph;
1206
1207 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1208 struct sec_path *sp = skb_sec_path(skb);
1209 int nh;
1210
1211 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
1212 XFRM_STATE_ICMP)) {
1213 reason = SKB_DROP_REASON_XFRM_POLICY;
1214 goto drop;
1215 }
1216
1217 if (!pskb_may_pull(skb, sizeof(*icmph) + sizeof(struct iphdr)))
1218 goto drop;
1219
1220 nh = skb_network_offset(skb);
1221 skb_set_network_header(skb, sizeof(*icmph));
1222
1223 if (!xfrm4_policy_check_reverse(NULL, XFRM_POLICY_IN,
1224 skb)) {
1225 reason = SKB_DROP_REASON_XFRM_POLICY;
1226 goto drop;
1227 }
1228
1229 skb_set_network_header(skb, nh);
1230 }
1231
1232 __ICMP_INC_STATS(net, ICMP_MIB_INMSGS);
1233
1234 if (skb_checksum_simple_validate(skb))
1235 goto csum_error;
1236
1237 if (!pskb_pull(skb, sizeof(*icmph)))
1238 goto error;
1239
1240 icmph = icmp_hdr(skb);
1241
1242 ICMPMSGIN_INC_STATS(net, icmph->type);
1243
1244 /* Check for ICMP Extended Echo (PROBE) messages */
1245 if (icmph->type == ICMP_EXT_ECHO) {
1246 /* We can't use icmp_pointers[].handler() because it is an array of
1247 * size NR_ICMP_TYPES + 1 (19 elements) and PROBE has code 42.
1248 */
1249 reason = icmp_echo(skb);
1250 goto reason_check;
1251 }
1252
1253 if (icmph->type == ICMP_EXT_ECHOREPLY) {
1254 reason = ping_rcv(skb);
1255 goto reason_check;
1256 }
1257
1258 /*
1259 * 18 is the highest 'known' ICMP type. Anything else is a mystery
1260 *
1261 * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
1262 * discarded.
1263 */
1264 if (icmph->type > NR_ICMP_TYPES) {
1265 reason = SKB_DROP_REASON_UNHANDLED_PROTO;
1266 goto error;
1267 }
1268
1269 /*
1270 * Parse the ICMP message
1271 */
1272
1273 if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
1274 /*
1275 * RFC 1122: 3.2.2.6 An ICMP_ECHO to broadcast MAY be
1276 * silently ignored (we let user decide with a sysctl).
1277 * RFC 1122: 3.2.2.8 An ICMP_TIMESTAMP MAY be silently
1278 * discarded if to broadcast/multicast.
1279 */
1280 if ((icmph->type == ICMP_ECHO ||
1281 icmph->type == ICMP_TIMESTAMP) &&
1282 READ_ONCE(net->ipv4.sysctl_icmp_echo_ignore_broadcasts)) {
1283 reason = SKB_DROP_REASON_INVALID_PROTO;
1284 goto error;
1285 }
1286 if (icmph->type != ICMP_ECHO &&
1287 icmph->type != ICMP_TIMESTAMP &&
1288 icmph->type != ICMP_ADDRESS &&
1289 icmph->type != ICMP_ADDRESSREPLY) {
1290 reason = SKB_DROP_REASON_INVALID_PROTO;
1291 goto error;
1292 }
1293 }
1294
1295 reason = icmp_pointers[icmph->type].handler(skb);
1296reason_check:
1297 if (!reason) {
1298 consume_skb(skb);
1299 return NET_RX_SUCCESS;
1300 }
1301
1302drop:
1303 kfree_skb_reason(skb, reason);
1304 return NET_RX_DROP;
1305csum_error:
1306 reason = SKB_DROP_REASON_ICMP_CSUM;
1307 __ICMP_INC_STATS(net, ICMP_MIB_CSUMERRORS);
1308error:
1309 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
1310 goto drop;
1311}
1312
1313static bool ip_icmp_error_rfc4884_validate(const struct sk_buff *skb, int off)
1314{
1315 struct icmp_extobj_hdr *objh, _objh;
1316 struct icmp_ext_hdr *exth, _exth;
1317 u16 olen;
1318
1319 exth = skb_header_pointer(skb, off, sizeof(_exth), &_exth);
1320 if (!exth)
1321 return false;
1322 if (exth->version != 2)
1323 return true;
1324
1325 if (exth->checksum &&
1326 csum_fold(skb_checksum(skb, off, skb->len - off, 0)))
1327 return false;
1328
1329 off += sizeof(_exth);
1330 while (off < skb->len) {
1331 objh = skb_header_pointer(skb, off, sizeof(_objh), &_objh);
1332 if (!objh)
1333 return false;
1334
1335 olen = ntohs(objh->length);
1336 if (olen < sizeof(_objh))
1337 return false;
1338
1339 off += olen;
1340 if (off > skb->len)
1341 return false;
1342 }
1343
1344 return true;
1345}
1346
1347void ip_icmp_error_rfc4884(const struct sk_buff *skb,
1348 struct sock_ee_data_rfc4884 *out,
1349 int thlen, int off)
1350{
1351 int hlen;
1352
1353 /* original datagram headers: end of icmph to payload (skb->data) */
1354 hlen = -skb_transport_offset(skb) - thlen;
1355
1356 /* per rfc 4884: minimal datagram length of 128 bytes */
1357 if (off < 128 || off < hlen)
1358 return;
1359
1360 /* kernel has stripped headers: return payload offset in bytes */
1361 off -= hlen;
1362 if (off + sizeof(struct icmp_ext_hdr) > skb->len)
1363 return;
1364
1365 out->len = off;
1366
1367 if (!ip_icmp_error_rfc4884_validate(skb, off))
1368 out->flags |= SO_EE_RFC4884_FLAG_INVALID;
1369}
1370EXPORT_SYMBOL_GPL(ip_icmp_error_rfc4884);
1371
1372int icmp_err(struct sk_buff *skb, u32 info)
1373{
1374 struct iphdr *iph = (struct iphdr *)skb->data;
1375 int offset = iph->ihl<<2;
1376 struct icmphdr *icmph = (struct icmphdr *)(skb->data + offset);
1377 struct net *net = dev_net_rcu(skb->dev);
1378 int type = icmp_hdr(skb)->type;
1379 int code = icmp_hdr(skb)->code;
1380
1381 /*
1382 * Use ping_err to handle all icmp errors except those
1383 * triggered by ICMP_ECHOREPLY which sent from kernel.
1384 */
1385 if (icmph->type != ICMP_ECHOREPLY) {
1386 ping_err(skb, offset, info);
1387 return 0;
1388 }
1389
1390 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
1391 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ICMP);
1392 else if (type == ICMP_REDIRECT)
1393 ipv4_redirect(skb, net, 0, IPPROTO_ICMP);
1394
1395 return 0;
1396}
1397
1398/*
1399 * This table is the definition of how we handle ICMP.
1400 */
1401static const struct icmp_control icmp_pointers[NR_ICMP_TYPES + 1] = {
1402 [ICMP_ECHOREPLY] = {
1403 .handler = ping_rcv,
1404 },
1405 [1] = {
1406 .handler = icmp_discard,
1407 .error = 1,
1408 },
1409 [2] = {
1410 .handler = icmp_discard,
1411 .error = 1,
1412 },
1413 [ICMP_DEST_UNREACH] = {
1414 .handler = icmp_unreach,
1415 .error = 1,
1416 },
1417 [ICMP_SOURCE_QUENCH] = {
1418 .handler = icmp_unreach,
1419 .error = 1,
1420 },
1421 [ICMP_REDIRECT] = {
1422 .handler = icmp_redirect,
1423 .error = 1,
1424 },
1425 [6] = {
1426 .handler = icmp_discard,
1427 .error = 1,
1428 },
1429 [7] = {
1430 .handler = icmp_discard,
1431 .error = 1,
1432 },
1433 [ICMP_ECHO] = {
1434 .handler = icmp_echo,
1435 },
1436 [9] = {
1437 .handler = icmp_discard,
1438 .error = 1,
1439 },
1440 [10] = {
1441 .handler = icmp_discard,
1442 .error = 1,
1443 },
1444 [ICMP_TIME_EXCEEDED] = {
1445 .handler = icmp_unreach,
1446 .error = 1,
1447 },
1448 [ICMP_PARAMETERPROB] = {
1449 .handler = icmp_unreach,
1450 .error = 1,
1451 },
1452 [ICMP_TIMESTAMP] = {
1453 .handler = icmp_timestamp,
1454 },
1455 [ICMP_TIMESTAMPREPLY] = {
1456 .handler = icmp_discard,
1457 },
1458 [ICMP_INFO_REQUEST] = {
1459 .handler = icmp_discard,
1460 },
1461 [ICMP_INFO_REPLY] = {
1462 .handler = icmp_discard,
1463 },
1464 [ICMP_ADDRESS] = {
1465 .handler = icmp_discard,
1466 },
1467 [ICMP_ADDRESSREPLY] = {
1468 .handler = icmp_discard,
1469 },
1470};
1471
1472static int __net_init icmp_sk_init(struct net *net)
1473{
1474 /* Control parameters for ECHO replies. */
1475 net->ipv4.sysctl_icmp_echo_ignore_all = 0;
1476 net->ipv4.sysctl_icmp_echo_enable_probe = 0;
1477 net->ipv4.sysctl_icmp_echo_ignore_broadcasts = 1;
1478
1479 /* Control parameter - ignore bogus broadcast responses? */
1480 net->ipv4.sysctl_icmp_ignore_bogus_error_responses = 1;
1481
1482 /*
1483 * Configurable global rate limit.
1484 *
1485 * ratelimit defines tokens/packet consumed for dst->rate_token
1486 * bucket ratemask defines which icmp types are ratelimited by
1487 * setting it's bit position.
1488 *
1489 * default:
1490 * dest unreachable (3), source quench (4),
1491 * time exceeded (11), parameter problem (12)
1492 */
1493
1494 net->ipv4.sysctl_icmp_ratelimit = 1 * HZ;
1495 net->ipv4.sysctl_icmp_ratemask = 0x1818;
1496 net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr = 0;
1497 net->ipv4.sysctl_icmp_msgs_per_sec = 1000;
1498 net->ipv4.sysctl_icmp_msgs_burst = 50;
1499
1500 return 0;
1501}
1502
1503static struct pernet_operations __net_initdata icmp_sk_ops = {
1504 .init = icmp_sk_init,
1505};
1506
1507int __init icmp_init(void)
1508{
1509 int err, i;
1510
1511 for_each_possible_cpu(i) {
1512 struct sock *sk;
1513
1514 err = inet_ctl_sock_create(&sk, PF_INET,
1515 SOCK_RAW, IPPROTO_ICMP, &init_net);
1516 if (err < 0)
1517 return err;
1518
1519 per_cpu(ipv4_icmp_sk, i) = sk;
1520
1521 /* Enough space for 2 64K ICMP packets, including
1522 * sk_buff/skb_shared_info struct overhead.
1523 */
1524 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
1525
1526 /*
1527 * Speedup sock_wfree()
1528 */
1529 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1530 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DONT;
1531 }
1532 return register_pernet_subsys(&icmp_sk_ops);
1533}