Line data Source code
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 :
96 : /*
97 : * Build xmit assembly blocks
98 : */
99 :
100 : struct icmp_bxm {
101 : struct sk_buff *skb;
102 : int offset;
103 : int data_len;
104 :
105 : struct {
106 : struct icmphdr icmph;
107 : __be32 times[3];
108 : } data;
109 : int head_len;
110 : struct ip_options_data replyopts;
111 : };
112 :
113 : /* An array of errno for error messages from dest unreach. */
114 : /* RFC 1122: 3.2.2.1 States that NET_UNREACH, HOST_UNREACH and SR_FAILED MUST be considered 'transient errs'. */
115 :
116 : const struct icmp_err icmp_err_convert[] = {
117 : {
118 : .errno = ENETUNREACH, /* ICMP_NET_UNREACH */
119 : .fatal = 0,
120 : },
121 : {
122 : .errno = EHOSTUNREACH, /* ICMP_HOST_UNREACH */
123 : .fatal = 0,
124 : },
125 : {
126 : .errno = ENOPROTOOPT /* ICMP_PROT_UNREACH */,
127 : .fatal = 1,
128 : },
129 : {
130 : .errno = ECONNREFUSED, /* ICMP_PORT_UNREACH */
131 : .fatal = 1,
132 : },
133 : {
134 : .errno = EMSGSIZE, /* ICMP_FRAG_NEEDED */
135 : .fatal = 0,
136 : },
137 : {
138 : .errno = EOPNOTSUPP, /* ICMP_SR_FAILED */
139 : .fatal = 0,
140 : },
141 : {
142 : .errno = ENETUNREACH, /* ICMP_NET_UNKNOWN */
143 : .fatal = 1,
144 : },
145 : {
146 : .errno = EHOSTDOWN, /* ICMP_HOST_UNKNOWN */
147 : .fatal = 1,
148 : },
149 : {
150 : .errno = ENONET, /* ICMP_HOST_ISOLATED */
151 : .fatal = 1,
152 : },
153 : {
154 : .errno = ENETUNREACH, /* ICMP_NET_ANO */
155 : .fatal = 1,
156 : },
157 : {
158 : .errno = EHOSTUNREACH, /* ICMP_HOST_ANO */
159 : .fatal = 1,
160 : },
161 : {
162 : .errno = ENETUNREACH, /* ICMP_NET_UNR_TOS */
163 : .fatal = 0,
164 : },
165 : {
166 : .errno = EHOSTUNREACH, /* ICMP_HOST_UNR_TOS */
167 : .fatal = 0,
168 : },
169 : {
170 : .errno = EHOSTUNREACH, /* ICMP_PKT_FILTERED */
171 : .fatal = 1,
172 : },
173 : {
174 : .errno = EHOSTUNREACH, /* ICMP_PREC_VIOLATION */
175 : .fatal = 1,
176 : },
177 : {
178 : .errno = EHOSTUNREACH, /* ICMP_PREC_CUTOFF */
179 : .fatal = 1,
180 : },
181 : };
182 : EXPORT_SYMBOL(icmp_err_convert);
183 :
184 : /*
185 : * ICMP control array. This specifies what to do with each ICMP.
186 : */
187 :
188 : struct icmp_control {
189 : bool (*handler)(struct sk_buff *skb);
190 : short error; /* This ICMP is classed as an error message */
191 : };
192 :
193 : static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1];
194 :
195 : /*
196 : * The ICMP socket(s). This is the most convenient way to flow control
197 : * our ICMP output as well as maintain a clean interface throughout
198 : * all layers. All Socketless IP sends will soon be gone.
199 : *
200 : * On SMP we have one ICMP socket per-cpu.
201 : */
202 0 : static struct sock *icmp_sk(struct net *net)
203 : {
204 0 : return this_cpu_read(*net->ipv4.icmp_sk);
205 : }
206 :
207 : /* Called with BH disabled */
208 0 : static inline struct sock *icmp_xmit_lock(struct net *net)
209 : {
210 0 : struct sock *sk;
211 :
212 0 : sk = icmp_sk(net);
213 :
214 0 : if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
215 : /* This can happen if the output path signals a
216 : * dst_link_failure() for an outgoing ICMP packet.
217 : */
218 0 : return NULL;
219 : }
220 : return sk;
221 : }
222 :
223 0 : static inline void icmp_xmit_unlock(struct sock *sk)
224 : {
225 0 : spin_unlock(&sk->sk_lock.slock);
226 0 : }
227 :
228 : int sysctl_icmp_msgs_per_sec __read_mostly = 1000;
229 : int sysctl_icmp_msgs_burst __read_mostly = 50;
230 :
231 : static struct {
232 : spinlock_t lock;
233 : u32 credit;
234 : u32 stamp;
235 : } icmp_global = {
236 : .lock = __SPIN_LOCK_UNLOCKED(icmp_global.lock),
237 : };
238 :
239 : /**
240 : * icmp_global_allow - Are we allowed to send one more ICMP message ?
241 : *
242 : * Uses a token bucket to limit our ICMP messages to ~sysctl_icmp_msgs_per_sec.
243 : * Returns false if we reached the limit and can not send another packet.
244 : * Note: called with BH disabled
245 : */
246 0 : bool icmp_global_allow(void)
247 : {
248 0 : u32 credit, delta, incr = 0, now = (u32)jiffies;
249 0 : bool rc = false;
250 :
251 : /* Check if token bucket is empty and cannot be refilled
252 : * without taking the spinlock. The READ_ONCE() are paired
253 : * with the following WRITE_ONCE() in this same function.
254 : */
255 0 : if (!READ_ONCE(icmp_global.credit)) {
256 0 : delta = min_t(u32, now - READ_ONCE(icmp_global.stamp), HZ);
257 0 : if (delta < HZ / 50)
258 : return false;
259 : }
260 :
261 0 : spin_lock(&icmp_global.lock);
262 0 : delta = min_t(u32, now - icmp_global.stamp, HZ);
263 0 : if (delta >= HZ / 50) {
264 0 : incr = sysctl_icmp_msgs_per_sec * delta / HZ ;
265 0 : if (incr)
266 0 : WRITE_ONCE(icmp_global.stamp, now);
267 : }
268 0 : credit = min_t(u32, icmp_global.credit + incr, sysctl_icmp_msgs_burst);
269 0 : if (credit) {
270 : /* We want to use a credit of one in average, but need to randomize
271 : * it for security reasons.
272 : */
273 0 : credit = max_t(int, credit - prandom_u32_max(3), 0);
274 0 : rc = true;
275 : }
276 0 : WRITE_ONCE(icmp_global.credit, credit);
277 0 : spin_unlock(&icmp_global.lock);
278 0 : return rc;
279 : }
280 : EXPORT_SYMBOL(icmp_global_allow);
281 :
282 0 : static bool icmpv4_mask_allow(struct net *net, int type, int code)
283 : {
284 0 : if (type > NR_ICMP_TYPES)
285 : return true;
286 :
287 : /* Don't limit PMTU discovery. */
288 0 : if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
289 : return true;
290 :
291 : /* Limit if icmp type is enabled in ratemask. */
292 0 : if (!((1 << type) & net->ipv4.sysctl_icmp_ratemask))
293 : return true;
294 :
295 : return false;
296 : }
297 :
298 0 : static bool icmpv4_global_allow(struct net *net, int type, int code)
299 : {
300 0 : if (icmpv4_mask_allow(net, type, code))
301 : return true;
302 :
303 0 : if (icmp_global_allow())
304 0 : return true;
305 :
306 : return false;
307 : }
308 :
309 : /*
310 : * Send an ICMP frame.
311 : */
312 :
313 0 : static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
314 : struct flowi4 *fl4, int type, int code)
315 : {
316 0 : struct dst_entry *dst = &rt->dst;
317 0 : struct inet_peer *peer;
318 0 : bool rc = true;
319 0 : int vif;
320 :
321 0 : if (icmpv4_mask_allow(net, type, code))
322 0 : goto out;
323 :
324 : /* No rate limit on loopback */
325 0 : if (dst->dev && (dst->dev->flags&IFF_LOOPBACK))
326 0 : goto out;
327 :
328 0 : vif = l3mdev_master_ifindex(dst->dev);
329 0 : peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr, vif, 1);
330 0 : rc = inet_peer_xrlim_allow(peer, net->ipv4.sysctl_icmp_ratelimit);
331 0 : if (peer)
332 0 : inet_putpeer(peer);
333 0 : out:
334 0 : return rc;
335 : }
336 :
337 : /*
338 : * Maintain the counters used in the SNMP statistics for outgoing ICMP
339 : */
340 0 : void icmp_out_count(struct net *net, unsigned char type)
341 : {
342 0 : ICMPMSGOUT_INC_STATS(net, type);
343 0 : ICMP_INC_STATS(net, ICMP_MIB_OUTMSGS);
344 0 : }
345 :
346 : /*
347 : * Checksum each fragment, and on the first include the headers and final
348 : * checksum.
349 : */
350 0 : static int icmp_glue_bits(void *from, char *to, int offset, int len, int odd,
351 : struct sk_buff *skb)
352 : {
353 0 : struct icmp_bxm *icmp_param = (struct icmp_bxm *)from;
354 0 : __wsum csum;
355 :
356 0 : csum = skb_copy_and_csum_bits(icmp_param->skb,
357 0 : icmp_param->offset + offset,
358 : to, len);
359 :
360 0 : skb->csum = csum_block_add(skb->csum, csum, odd);
361 0 : if (icmp_pointers[icmp_param->data.icmph.type].error)
362 0 : nf_ct_attach(skb, icmp_param->skb);
363 0 : return 0;
364 : }
365 :
366 0 : static void icmp_push_reply(struct icmp_bxm *icmp_param,
367 : struct flowi4 *fl4,
368 : struct ipcm_cookie *ipc, struct rtable **rt)
369 : {
370 0 : struct sock *sk;
371 0 : struct sk_buff *skb;
372 :
373 0 : sk = icmp_sk(dev_net((*rt)->dst.dev));
374 0 : if (ip_append_data(sk, fl4, icmp_glue_bits, icmp_param,
375 0 : icmp_param->data_len+icmp_param->head_len,
376 : icmp_param->head_len,
377 : ipc, rt, MSG_DONTWAIT) < 0) {
378 0 : __ICMP_INC_STATS(sock_net(sk), ICMP_MIB_OUTERRORS);
379 0 : ip_flush_pending_frames(sk);
380 0 : } else if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) {
381 0 : struct icmphdr *icmph = icmp_hdr(skb);
382 0 : __wsum csum;
383 0 : struct sk_buff *skb1;
384 :
385 0 : csum = csum_partial_copy_nocheck((void *)&icmp_param->data,
386 : (char *)icmph,
387 : icmp_param->head_len);
388 0 : skb_queue_walk(&sk->sk_write_queue, skb1) {
389 0 : csum = csum_add(csum, skb1->csum);
390 : }
391 0 : icmph->checksum = csum_fold(csum);
392 0 : skb->ip_summed = CHECKSUM_NONE;
393 0 : ip_push_pending_frames(sk, fl4);
394 : }
395 0 : }
396 :
397 : /*
398 : * Driving logic for building and sending ICMP messages.
399 : */
400 :
401 0 : static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
402 : {
403 0 : struct ipcm_cookie ipc;
404 0 : struct rtable *rt = skb_rtable(skb);
405 0 : struct net *net = dev_net(rt->dst.dev);
406 0 : struct flowi4 fl4;
407 0 : struct sock *sk;
408 0 : struct inet_sock *inet;
409 0 : __be32 daddr, saddr;
410 0 : u32 mark = IP4_REPLY_MARK(net, skb->mark);
411 0 : int type = icmp_param->data.icmph.type;
412 0 : int code = icmp_param->data.icmph.code;
413 :
414 0 : if (ip_options_echo(net, &icmp_param->replyopts.opt.opt, skb))
415 0 : return;
416 :
417 : /* Needed by both icmp_global_allow and icmp_xmit_lock */
418 0 : local_bh_disable();
419 :
420 : /* global icmp_msgs_per_sec */
421 0 : if (!icmpv4_global_allow(net, type, code))
422 0 : goto out_bh_enable;
423 :
424 0 : sk = icmp_xmit_lock(net);
425 0 : if (!sk)
426 0 : goto out_bh_enable;
427 0 : inet = inet_sk(sk);
428 :
429 0 : icmp_param->data.icmph.checksum = 0;
430 :
431 0 : ipcm_init(&ipc);
432 0 : inet->tos = ip_hdr(skb)->tos;
433 0 : ipc.sockc.mark = mark;
434 0 : daddr = ipc.addr = ip_hdr(skb)->saddr;
435 0 : saddr = fib_compute_spec_dst(skb);
436 :
437 0 : if (icmp_param->replyopts.opt.opt.optlen) {
438 0 : ipc.opt = &icmp_param->replyopts.opt;
439 0 : if (ipc.opt->opt.srr)
440 0 : daddr = icmp_param->replyopts.opt.opt.faddr;
441 : }
442 0 : memset(&fl4, 0, sizeof(fl4));
443 0 : fl4.daddr = daddr;
444 0 : fl4.saddr = saddr;
445 0 : fl4.flowi4_mark = mark;
446 0 : fl4.flowi4_uid = sock_net_uid(net, NULL);
447 0 : fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);
448 0 : fl4.flowi4_proto = IPPROTO_ICMP;
449 0 : fl4.flowi4_oif = l3mdev_master_ifindex(skb->dev);
450 0 : security_skb_classify_flow(skb, flowi4_to_flowi_common(&fl4));
451 0 : rt = ip_route_output_key(net, &fl4);
452 0 : if (IS_ERR(rt))
453 0 : goto out_unlock;
454 0 : if (icmpv4_xrlim_allow(net, rt, &fl4, type, code))
455 0 : icmp_push_reply(icmp_param, &fl4, &ipc, &rt);
456 0 : ip_rt_put(rt);
457 0 : out_unlock:
458 0 : icmp_xmit_unlock(sk);
459 0 : out_bh_enable:
460 0 : 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 : */
469 0 : static struct net_device *icmp_get_route_lookup_dev(struct sk_buff *skb)
470 : {
471 0 : struct net_device *route_lookup_dev = NULL;
472 :
473 0 : if (skb->dev)
474 : route_lookup_dev = skb->dev;
475 0 : else if (skb_dst(skb))
476 0 : route_lookup_dev = skb_dst(skb)->dev;
477 0 : return route_lookup_dev;
478 : }
479 :
480 0 : static struct rtable *icmp_route_lookup(struct net *net,
481 : struct flowi4 *fl4,
482 : struct sk_buff *skb_in,
483 : const struct iphdr *iph,
484 : __be32 saddr, u8 tos, u32 mark,
485 : int type, int code,
486 : struct icmp_bxm *param)
487 : {
488 0 : struct net_device *route_lookup_dev;
489 0 : struct rtable *rt, *rt2;
490 0 : struct flowi4 fl4_dec;
491 0 : int err;
492 :
493 0 : memset(fl4, 0, sizeof(*fl4));
494 0 : fl4->daddr = (param->replyopts.opt.opt.srr ?
495 0 : param->replyopts.opt.opt.faddr : iph->saddr);
496 0 : fl4->saddr = saddr;
497 0 : fl4->flowi4_mark = mark;
498 0 : fl4->flowi4_uid = sock_net_uid(net, NULL);
499 0 : fl4->flowi4_tos = RT_TOS(tos);
500 0 : fl4->flowi4_proto = IPPROTO_ICMP;
501 0 : fl4->fl4_icmp_type = type;
502 0 : fl4->fl4_icmp_code = code;
503 0 : route_lookup_dev = icmp_get_route_lookup_dev(skb_in);
504 0 : fl4->flowi4_oif = l3mdev_master_ifindex(route_lookup_dev);
505 :
506 0 : security_skb_classify_flow(skb_in, flowi4_to_flowi_common(fl4));
507 0 : rt = ip_route_output_key_hash(net, fl4, skb_in);
508 0 : if (IS_ERR(rt))
509 : return rt;
510 :
511 : /* No need to clone since we're just using its address. */
512 0 : rt2 = rt;
513 :
514 0 : rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
515 0 : flowi4_to_flowi(fl4), NULL, 0);
516 0 : if (!IS_ERR(rt)) {
517 : if (rt != rt2)
518 : return rt;
519 0 : } else if (PTR_ERR(rt) == -EPERM) {
520 : rt = NULL;
521 : } else
522 : return rt;
523 :
524 0 : err = xfrm_decode_session_reverse(skb_in, flowi4_to_flowi(&fl4_dec), AF_INET);
525 0 : if (err)
526 0 : goto relookup_failed;
527 :
528 : if (inet_addr_type_dev_table(net, route_lookup_dev,
529 : fl4_dec.saddr) == RTN_LOCAL) {
530 : rt2 = __ip_route_output_key(net, &fl4_dec);
531 : if (IS_ERR(rt2))
532 : err = PTR_ERR(rt2);
533 : } else {
534 : struct flowi4 fl4_2 = {};
535 : unsigned long orefdst;
536 :
537 : fl4_2.daddr = fl4_dec.saddr;
538 : rt2 = ip_route_output_key(net, &fl4_2);
539 : if (IS_ERR(rt2)) {
540 : err = PTR_ERR(rt2);
541 : goto relookup_failed;
542 : }
543 : /* Ugh! */
544 : orefdst = skb_in->_skb_refdst; /* save old refdst */
545 : skb_dst_set(skb_in, NULL);
546 : err = ip_route_input(skb_in, fl4_dec.daddr, fl4_dec.saddr,
547 : RT_TOS(tos), rt2->dst.dev);
548 :
549 : dst_release(&rt2->dst);
550 : rt2 = skb_rtable(skb_in);
551 : skb_in->_skb_refdst = orefdst; /* restore old refdst */
552 : }
553 :
554 : if (err)
555 : goto relookup_failed;
556 :
557 : rt2 = (struct rtable *) xfrm_lookup(net, &rt2->dst,
558 : flowi4_to_flowi(&fl4_dec), NULL,
559 : XFRM_LOOKUP_ICMP);
560 : if (!IS_ERR(rt2)) {
561 : dst_release(&rt->dst);
562 : memcpy(fl4, &fl4_dec, sizeof(*fl4));
563 : rt = rt2;
564 : } else if (PTR_ERR(rt2) == -EPERM) {
565 : if (rt)
566 : dst_release(&rt->dst);
567 : return rt2;
568 : } else {
569 : err = PTR_ERR(rt2);
570 : goto relookup_failed;
571 : }
572 : return rt;
573 :
574 0 : relookup_failed:
575 0 : if (rt)
576 0 : return rt;
577 0 : return ERR_PTR(err);
578 : }
579 :
580 : /*
581 : * Send an ICMP message in response to a situation
582 : *
583 : * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header.
584 : * MAY send more (we do).
585 : * MUST NOT change this header information.
586 : * MUST NOT reply to a multicast/broadcast IP address.
587 : * MUST NOT reply to a multicast/broadcast MAC address.
588 : * MUST reply to only the first fragment.
589 : */
590 :
591 0 : void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info,
592 : const struct ip_options *opt)
593 : {
594 0 : struct iphdr *iph;
595 0 : int room;
596 0 : struct icmp_bxm icmp_param;
597 0 : struct rtable *rt = skb_rtable(skb_in);
598 0 : struct ipcm_cookie ipc;
599 0 : struct flowi4 fl4;
600 0 : __be32 saddr;
601 0 : u8 tos;
602 0 : u32 mark;
603 0 : struct net *net;
604 0 : struct sock *sk;
605 :
606 0 : if (!rt)
607 0 : goto out;
608 :
609 0 : if (rt->dst.dev)
610 0 : net = dev_net(rt->dst.dev);
611 0 : else if (skb_in->dev)
612 0 : net = dev_net(skb_in->dev);
613 : else
614 0 : goto out;
615 :
616 : /*
617 : * Find the original header. It is expected to be valid, of course.
618 : * Check this, icmp_send is called from the most obscure devices
619 : * sometimes.
620 : */
621 0 : iph = ip_hdr(skb_in);
622 :
623 0 : if ((u8 *)iph < skb_in->head ||
624 0 : (skb_network_header(skb_in) + sizeof(*iph)) >
625 0 : skb_tail_pointer(skb_in))
626 0 : goto out;
627 :
628 : /*
629 : * No replies to physical multicast/broadcast
630 : */
631 0 : if (skb_in->pkt_type != PACKET_HOST)
632 0 : goto out;
633 :
634 : /*
635 : * Now check at the protocol level
636 : */
637 0 : if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
638 0 : goto out;
639 :
640 : /*
641 : * Only reply to fragment 0. We byte re-order the constant
642 : * mask for efficiency.
643 : */
644 0 : if (iph->frag_off & htons(IP_OFFSET))
645 0 : goto out;
646 :
647 : /*
648 : * If we send an ICMP error to an ICMP error a mess would result..
649 : */
650 0 : if (icmp_pointers[type].error) {
651 : /*
652 : * We are an error, check if we are replying to an
653 : * ICMP error
654 : */
655 0 : if (iph->protocol == IPPROTO_ICMP) {
656 0 : u8 _inner_type, *itp;
657 :
658 0 : itp = skb_header_pointer(skb_in,
659 0 : skb_network_header(skb_in) +
660 0 : (iph->ihl << 2) +
661 : offsetof(struct icmphdr,
662 0 : type) -
663 0 : skb_in->data,
664 : sizeof(_inner_type),
665 : &_inner_type);
666 0 : if (!itp)
667 0 : goto out;
668 :
669 : /*
670 : * Assume any unknown ICMP type is an error. This
671 : * isn't specified by the RFC, but think about it..
672 : */
673 0 : if (*itp > NR_ICMP_TYPES ||
674 0 : icmp_pointers[*itp].error)
675 0 : goto out;
676 : }
677 : }
678 :
679 : /* Needed by both icmp_global_allow and icmp_xmit_lock */
680 0 : local_bh_disable();
681 :
682 : /* Check global sysctl_icmp_msgs_per_sec ratelimit, unless
683 : * incoming dev is loopback. If outgoing dev change to not be
684 : * loopback, then peer ratelimit still work (in icmpv4_xrlim_allow)
685 : */
686 0 : if (!(skb_in->dev && (skb_in->dev->flags&IFF_LOOPBACK)) &&
687 0 : !icmpv4_global_allow(net, type, code))
688 0 : goto out_bh_enable;
689 :
690 0 : sk = icmp_xmit_lock(net);
691 0 : if (!sk)
692 0 : goto out_bh_enable;
693 :
694 : /*
695 : * Construct source address and options.
696 : */
697 :
698 0 : saddr = iph->daddr;
699 0 : if (!(rt->rt_flags & RTCF_LOCAL)) {
700 0 : struct net_device *dev = NULL;
701 :
702 0 : rcu_read_lock();
703 0 : if (rt_is_input_route(rt) &&
704 0 : net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr)
705 0 : dev = dev_get_by_index_rcu(net, inet_iif(skb_in));
706 :
707 0 : if (dev)
708 0 : saddr = inet_select_addr(dev, iph->saddr,
709 : RT_SCOPE_LINK);
710 : else
711 : saddr = 0;
712 0 : rcu_read_unlock();
713 : }
714 :
715 0 : tos = icmp_pointers[type].error ? (RT_TOS(iph->tos) |
716 : IPTOS_PREC_INTERNETCONTROL) :
717 : iph->tos;
718 0 : mark = IP4_REPLY_MARK(net, skb_in->mark);
719 :
720 0 : if (__ip_options_echo(net, &icmp_param.replyopts.opt.opt, skb_in, opt))
721 0 : goto out_unlock;
722 :
723 :
724 : /*
725 : * Prepare data for ICMP header.
726 : */
727 :
728 0 : icmp_param.data.icmph.type = type;
729 0 : icmp_param.data.icmph.code = code;
730 0 : icmp_param.data.icmph.un.gateway = info;
731 0 : icmp_param.data.icmph.checksum = 0;
732 0 : icmp_param.skb = skb_in;
733 0 : icmp_param.offset = skb_network_offset(skb_in);
734 0 : inet_sk(sk)->tos = tos;
735 0 : ipcm_init(&ipc);
736 0 : ipc.addr = iph->saddr;
737 0 : ipc.opt = &icmp_param.replyopts.opt;
738 0 : ipc.sockc.mark = mark;
739 :
740 0 : rt = icmp_route_lookup(net, &fl4, skb_in, iph, saddr, tos, mark,
741 : type, code, &icmp_param);
742 0 : if (IS_ERR(rt))
743 0 : goto out_unlock;
744 :
745 : /* peer icmp_ratelimit */
746 0 : if (!icmpv4_xrlim_allow(net, rt, &fl4, type, code))
747 0 : goto ende;
748 :
749 : /* RFC says return as much as we can without exceeding 576 bytes. */
750 :
751 0 : room = dst_mtu(&rt->dst);
752 0 : if (room > 576)
753 : room = 576;
754 0 : room -= sizeof(struct iphdr) + icmp_param.replyopts.opt.opt.optlen;
755 0 : room -= sizeof(struct icmphdr);
756 :
757 0 : icmp_param.data_len = skb_in->len - icmp_param.offset;
758 0 : if (icmp_param.data_len > room)
759 0 : icmp_param.data_len = room;
760 0 : icmp_param.head_len = sizeof(struct icmphdr);
761 :
762 0 : icmp_push_reply(&icmp_param, &fl4, &ipc, &rt);
763 0 : ende:
764 0 : ip_rt_put(rt);
765 0 : out_unlock:
766 0 : icmp_xmit_unlock(sk);
767 0 : out_bh_enable:
768 0 : local_bh_enable();
769 0 : out:;
770 0 : }
771 : EXPORT_SYMBOL(__icmp_send);
772 :
773 : #if IS_ENABLED(CONFIG_NF_NAT)
774 : #include <net/netfilter/nf_conntrack.h>
775 : void icmp_ndo_send(struct sk_buff *skb_in, int type, int code, __be32 info)
776 : {
777 : struct sk_buff *cloned_skb = NULL;
778 : struct ip_options opts = { 0 };
779 : enum ip_conntrack_info ctinfo;
780 : struct nf_conn *ct;
781 : __be32 orig_ip;
782 :
783 : ct = nf_ct_get(skb_in, &ctinfo);
784 : if (!ct || !(ct->status & IPS_SRC_NAT)) {
785 : __icmp_send(skb_in, type, code, info, &opts);
786 : return;
787 : }
788 :
789 : if (skb_shared(skb_in))
790 : skb_in = cloned_skb = skb_clone(skb_in, GFP_ATOMIC);
791 :
792 : if (unlikely(!skb_in || skb_network_header(skb_in) < skb_in->head ||
793 : (skb_network_header(skb_in) + sizeof(struct iphdr)) >
794 : skb_tail_pointer(skb_in) || skb_ensure_writable(skb_in,
795 : skb_network_offset(skb_in) + sizeof(struct iphdr))))
796 : goto out;
797 :
798 : orig_ip = ip_hdr(skb_in)->saddr;
799 : ip_hdr(skb_in)->saddr = ct->tuplehash[0].tuple.src.u3.ip;
800 : __icmp_send(skb_in, type, code, info, &opts);
801 : ip_hdr(skb_in)->saddr = orig_ip;
802 : out:
803 : consume_skb(cloned_skb);
804 : }
805 : EXPORT_SYMBOL(icmp_ndo_send);
806 : #endif
807 :
808 14 : static void icmp_socket_deliver(struct sk_buff *skb, u32 info)
809 : {
810 14 : const struct iphdr *iph = (const struct iphdr *)skb->data;
811 14 : const struct net_protocol *ipprot;
812 14 : int protocol = iph->protocol;
813 :
814 : /* Checkin full IP header plus 8 bytes of protocol to
815 : * avoid additional coding at protocol handlers.
816 : */
817 14 : if (!pskb_may_pull(skb, iph->ihl * 4 + 8)) {
818 0 : __ICMP_INC_STATS(dev_net(skb->dev), ICMP_MIB_INERRORS);
819 0 : return;
820 : }
821 :
822 14 : raw_icmp_error(skb, protocol, info);
823 :
824 14 : ipprot = rcu_dereference(inet_protos[protocol]);
825 14 : if (ipprot && ipprot->err_handler)
826 14 : ipprot->err_handler(skb, info);
827 : }
828 :
829 0 : static bool icmp_tag_validation(int proto)
830 : {
831 0 : bool ok;
832 :
833 0 : rcu_read_lock();
834 0 : ok = rcu_dereference(inet_protos[proto])->icmp_strict_tag_validation;
835 0 : rcu_read_unlock();
836 0 : return ok;
837 : }
838 :
839 : /*
840 : * Handle ICMP_DEST_UNREACH, ICMP_TIME_EXCEEDED, ICMP_QUENCH, and
841 : * ICMP_PARAMETERPROB.
842 : */
843 :
844 14 : static bool icmp_unreach(struct sk_buff *skb)
845 : {
846 14 : const struct iphdr *iph;
847 14 : struct icmphdr *icmph;
848 14 : struct net *net;
849 14 : u32 info = 0;
850 :
851 14 : net = dev_net(skb_dst(skb)->dev);
852 :
853 : /*
854 : * Incomplete header ?
855 : * Only checks for the IP header, there should be an
856 : * additional check for longer headers in upper levels.
857 : */
858 :
859 14 : if (!pskb_may_pull(skb, sizeof(struct iphdr)))
860 0 : goto out_err;
861 :
862 14 : icmph = icmp_hdr(skb);
863 14 : iph = (const struct iphdr *)skb->data;
864 :
865 14 : if (iph->ihl < 5) /* Mangled header, drop. */
866 0 : goto out_err;
867 :
868 14 : switch (icmph->type) {
869 14 : case ICMP_DEST_UNREACH:
870 14 : switch (icmph->code & 15) {
871 : case ICMP_NET_UNREACH:
872 : case ICMP_HOST_UNREACH:
873 : case ICMP_PROT_UNREACH:
874 : case ICMP_PORT_UNREACH:
875 : break;
876 0 : case ICMP_FRAG_NEEDED:
877 : /* for documentation of the ip_no_pmtu_disc
878 : * values please see
879 : * Documentation/networking/ip-sysctl.rst
880 : */
881 0 : switch (net->ipv4.sysctl_ip_no_pmtu_disc) {
882 : default:
883 : net_dbg_ratelimited("%pI4: fragmentation needed and DF set\n",
884 : &iph->daddr);
885 : break;
886 0 : case 2:
887 0 : goto out;
888 0 : case 3:
889 0 : if (!icmp_tag_validation(iph->protocol))
890 0 : goto out;
891 0 : fallthrough;
892 : case 0:
893 0 : info = ntohs(icmph->un.frag.mtu);
894 : }
895 : break;
896 : case ICMP_SR_FAILED:
897 : net_dbg_ratelimited("%pI4: Source Route Failed\n",
898 : &iph->daddr);
899 : break;
900 : default:
901 : break;
902 : }
903 14 : if (icmph->code > NR_ICMP_UNREACH)
904 0 : goto out;
905 : break;
906 0 : case ICMP_PARAMETERPROB:
907 0 : info = ntohl(icmph->un.gateway) >> 24;
908 0 : break;
909 : case ICMP_TIME_EXCEEDED:
910 0 : __ICMP_INC_STATS(net, ICMP_MIB_INTIMEEXCDS);
911 0 : if (icmph->code == ICMP_EXC_FRAGTIME)
912 0 : goto out;
913 : break;
914 : }
915 :
916 : /*
917 : * Throw it at our lower layers
918 : *
919 : * RFC 1122: 3.2.2 MUST extract the protocol ID from the passed
920 : * header.
921 : * RFC 1122: 3.2.2.1 MUST pass ICMP unreach messages to the
922 : * transport layer.
923 : * RFC 1122: 3.2.2.2 MUST pass ICMP time expired messages to
924 : * transport layer.
925 : */
926 :
927 : /*
928 : * Check the other end isn't violating RFC 1122. Some routers send
929 : * bogus responses to broadcast frames. If you see this message
930 : * first check your netmask matches at both ends, if it does then
931 : * get the other vendor to fix their kit.
932 : */
933 :
934 14 : if (!net->ipv4.sysctl_icmp_ignore_bogus_error_responses &&
935 0 : inet_addr_type_dev_table(net, skb->dev, iph->daddr) == RTN_BROADCAST) {
936 0 : net_warn_ratelimited("%pI4 sent an invalid ICMP type %u, code %u error to a broadcast: %pI4 on %s\n",
937 : &ip_hdr(skb)->saddr,
938 : icmph->type, icmph->code,
939 : &iph->daddr, skb->dev->name);
940 0 : goto out;
941 : }
942 :
943 14 : icmp_socket_deliver(skb, info);
944 :
945 : out:
946 : return true;
947 0 : out_err:
948 0 : __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
949 0 : return false;
950 : }
951 :
952 :
953 : /*
954 : * Handle ICMP_REDIRECT.
955 : */
956 :
957 0 : static bool icmp_redirect(struct sk_buff *skb)
958 : {
959 0 : if (skb->len < sizeof(struct iphdr)) {
960 0 : __ICMP_INC_STATS(dev_net(skb->dev), ICMP_MIB_INERRORS);
961 0 : return false;
962 : }
963 :
964 0 : if (!pskb_may_pull(skb, sizeof(struct iphdr))) {
965 : /* there aught to be a stat */
966 : return false;
967 : }
968 :
969 0 : icmp_socket_deliver(skb, ntohl(icmp_hdr(skb)->un.gateway));
970 0 : return true;
971 : }
972 :
973 : /*
974 : * Handle ICMP_ECHO ("ping") requests.
975 : *
976 : * RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo
977 : * requests.
978 : * RFC 1122: 3.2.2.6 Data received in the ICMP_ECHO request MUST be
979 : * included in the reply.
980 : * RFC 1812: 4.3.3.6 SHOULD have a config option for silently ignoring
981 : * echo requests, MUST have default=NOT.
982 : * See also WRT handling of options once they are done and working.
983 : */
984 :
985 0 : static bool icmp_echo(struct sk_buff *skb)
986 : {
987 0 : struct net *net;
988 :
989 0 : net = dev_net(skb_dst(skb)->dev);
990 0 : if (!net->ipv4.sysctl_icmp_echo_ignore_all) {
991 0 : struct icmp_bxm icmp_param;
992 :
993 0 : icmp_param.data.icmph = *icmp_hdr(skb);
994 0 : icmp_param.data.icmph.type = ICMP_ECHOREPLY;
995 0 : icmp_param.skb = skb;
996 0 : icmp_param.offset = 0;
997 0 : icmp_param.data_len = skb->len;
998 0 : icmp_param.head_len = sizeof(struct icmphdr);
999 0 : icmp_reply(&icmp_param, skb);
1000 : }
1001 : /* should there be an ICMP stat for ignored echos? */
1002 0 : return true;
1003 : }
1004 :
1005 : /*
1006 : * Handle ICMP Timestamp requests.
1007 : * RFC 1122: 3.2.2.8 MAY implement ICMP timestamp requests.
1008 : * SHOULD be in the kernel for minimum random latency.
1009 : * MUST be accurate to a few minutes.
1010 : * MUST be updated at least at 15Hz.
1011 : */
1012 0 : static bool icmp_timestamp(struct sk_buff *skb)
1013 : {
1014 0 : struct icmp_bxm icmp_param;
1015 : /*
1016 : * Too short.
1017 : */
1018 0 : if (skb->len < 4)
1019 0 : goto out_err;
1020 :
1021 : /*
1022 : * Fill in the current time as ms since midnight UT:
1023 : */
1024 0 : icmp_param.data.times[1] = inet_current_timestamp();
1025 0 : icmp_param.data.times[2] = icmp_param.data.times[1];
1026 :
1027 0 : BUG_ON(skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4));
1028 :
1029 0 : icmp_param.data.icmph = *icmp_hdr(skb);
1030 0 : icmp_param.data.icmph.type = ICMP_TIMESTAMPREPLY;
1031 0 : icmp_param.data.icmph.code = 0;
1032 0 : icmp_param.skb = skb;
1033 0 : icmp_param.offset = 0;
1034 0 : icmp_param.data_len = 0;
1035 0 : icmp_param.head_len = sizeof(struct icmphdr) + 12;
1036 0 : icmp_reply(&icmp_param, skb);
1037 0 : return true;
1038 :
1039 0 : out_err:
1040 0 : __ICMP_INC_STATS(dev_net(skb_dst(skb)->dev), ICMP_MIB_INERRORS);
1041 0 : return false;
1042 : }
1043 :
1044 0 : static bool icmp_discard(struct sk_buff *skb)
1045 : {
1046 : /* pretend it was a success */
1047 0 : return true;
1048 : }
1049 :
1050 : /*
1051 : * Deal with incoming ICMP packets.
1052 : */
1053 14 : int icmp_rcv(struct sk_buff *skb)
1054 : {
1055 14 : struct icmphdr *icmph;
1056 14 : struct rtable *rt = skb_rtable(skb);
1057 14 : struct net *net = dev_net(rt->dst.dev);
1058 14 : bool success;
1059 :
1060 14 : if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1061 : struct sec_path *sp = skb_sec_path(skb);
1062 : int nh;
1063 :
1064 : if (!(sp && sp->xvec[sp->len - 1]->props.flags &
1065 : XFRM_STATE_ICMP))
1066 : goto drop;
1067 :
1068 : if (!pskb_may_pull(skb, sizeof(*icmph) + sizeof(struct iphdr)))
1069 : goto drop;
1070 :
1071 : nh = skb_network_offset(skb);
1072 : skb_set_network_header(skb, sizeof(*icmph));
1073 :
1074 : if (!xfrm4_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
1075 : goto drop;
1076 :
1077 14 : skb_set_network_header(skb, nh);
1078 : }
1079 :
1080 14 : __ICMP_INC_STATS(net, ICMP_MIB_INMSGS);
1081 :
1082 14 : if (skb_checksum_simple_validate(skb))
1083 0 : goto csum_error;
1084 :
1085 28 : if (!pskb_pull(skb, sizeof(*icmph)))
1086 0 : goto error;
1087 :
1088 14 : icmph = icmp_hdr(skb);
1089 :
1090 14 : ICMPMSGIN_INC_STATS(net, icmph->type);
1091 : /*
1092 : * 18 is the highest 'known' ICMP type. Anything else is a mystery
1093 : *
1094 : * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
1095 : * discarded.
1096 : */
1097 14 : if (icmph->type > NR_ICMP_TYPES)
1098 0 : goto error;
1099 :
1100 :
1101 : /*
1102 : * Parse the ICMP message
1103 : */
1104 :
1105 14 : if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
1106 : /*
1107 : * RFC 1122: 3.2.2.6 An ICMP_ECHO to broadcast MAY be
1108 : * silently ignored (we let user decide with a sysctl).
1109 : * RFC 1122: 3.2.2.8 An ICMP_TIMESTAMP MAY be silently
1110 : * discarded if to broadcast/multicast.
1111 : */
1112 0 : if ((icmph->type == ICMP_ECHO ||
1113 0 : icmph->type == ICMP_TIMESTAMP) &&
1114 0 : net->ipv4.sysctl_icmp_echo_ignore_broadcasts) {
1115 0 : goto error;
1116 : }
1117 0 : if (icmph->type != ICMP_ECHO &&
1118 0 : icmph->type != ICMP_TIMESTAMP &&
1119 0 : icmph->type != ICMP_ADDRESS &&
1120 : icmph->type != ICMP_ADDRESSREPLY) {
1121 0 : goto error;
1122 : }
1123 : }
1124 :
1125 14 : success = icmp_pointers[icmph->type].handler(skb);
1126 :
1127 14 : if (success) {
1128 14 : consume_skb(skb);
1129 14 : return NET_RX_SUCCESS;
1130 : }
1131 :
1132 0 : drop:
1133 0 : kfree_skb(skb);
1134 0 : return NET_RX_DROP;
1135 0 : csum_error:
1136 0 : __ICMP_INC_STATS(net, ICMP_MIB_CSUMERRORS);
1137 0 : error:
1138 0 : __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
1139 0 : goto drop;
1140 : }
1141 :
1142 0 : static bool ip_icmp_error_rfc4884_validate(const struct sk_buff *skb, int off)
1143 : {
1144 0 : struct icmp_extobj_hdr *objh, _objh;
1145 0 : struct icmp_ext_hdr *exth, _exth;
1146 0 : u16 olen;
1147 :
1148 0 : exth = skb_header_pointer(skb, off, sizeof(_exth), &_exth);
1149 0 : if (!exth)
1150 : return false;
1151 0 : if (exth->version != 2)
1152 : return true;
1153 :
1154 0 : if (exth->checksum &&
1155 0 : csum_fold(skb_checksum(skb, off, skb->len - off, 0)))
1156 : return false;
1157 :
1158 0 : off += sizeof(_exth);
1159 0 : while (off < skb->len) {
1160 0 : objh = skb_header_pointer(skb, off, sizeof(_objh), &_objh);
1161 0 : if (!objh)
1162 : return false;
1163 :
1164 0 : olen = ntohs(objh->length);
1165 0 : if (olen < sizeof(_objh))
1166 : return false;
1167 :
1168 0 : off += olen;
1169 0 : if (off > skb->len)
1170 : return false;
1171 : }
1172 :
1173 : return true;
1174 : }
1175 :
1176 0 : void ip_icmp_error_rfc4884(const struct sk_buff *skb,
1177 : struct sock_ee_data_rfc4884 *out,
1178 : int thlen, int off)
1179 : {
1180 0 : int hlen;
1181 :
1182 : /* original datagram headers: end of icmph to payload (skb->data) */
1183 0 : hlen = -skb_transport_offset(skb) - thlen;
1184 :
1185 : /* per rfc 4884: minimal datagram length of 128 bytes */
1186 0 : if (off < 128 || off < hlen)
1187 : return;
1188 :
1189 : /* kernel has stripped headers: return payload offset in bytes */
1190 0 : off -= hlen;
1191 0 : if (off + sizeof(struct icmp_ext_hdr) > skb->len)
1192 : return;
1193 :
1194 0 : out->len = off;
1195 :
1196 0 : if (!ip_icmp_error_rfc4884_validate(skb, off))
1197 0 : out->flags |= SO_EE_RFC4884_FLAG_INVALID;
1198 : }
1199 : EXPORT_SYMBOL_GPL(ip_icmp_error_rfc4884);
1200 :
1201 0 : int icmp_err(struct sk_buff *skb, u32 info)
1202 : {
1203 0 : struct iphdr *iph = (struct iphdr *)skb->data;
1204 0 : int offset = iph->ihl<<2;
1205 0 : struct icmphdr *icmph = (struct icmphdr *)(skb->data + offset);
1206 0 : int type = icmp_hdr(skb)->type;
1207 0 : int code = icmp_hdr(skb)->code;
1208 0 : struct net *net = dev_net(skb->dev);
1209 :
1210 : /*
1211 : * Use ping_err to handle all icmp errors except those
1212 : * triggered by ICMP_ECHOREPLY which sent from kernel.
1213 : */
1214 0 : if (icmph->type != ICMP_ECHOREPLY) {
1215 0 : ping_err(skb, offset, info);
1216 0 : return 0;
1217 : }
1218 :
1219 0 : if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
1220 0 : ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ICMP);
1221 0 : else if (type == ICMP_REDIRECT)
1222 0 : ipv4_redirect(skb, net, 0, IPPROTO_ICMP);
1223 :
1224 : return 0;
1225 : }
1226 :
1227 : /*
1228 : * This table is the definition of how we handle ICMP.
1229 : */
1230 : static const struct icmp_control icmp_pointers[NR_ICMP_TYPES + 1] = {
1231 : [ICMP_ECHOREPLY] = {
1232 : .handler = ping_rcv,
1233 : },
1234 : [1] = {
1235 : .handler = icmp_discard,
1236 : .error = 1,
1237 : },
1238 : [2] = {
1239 : .handler = icmp_discard,
1240 : .error = 1,
1241 : },
1242 : [ICMP_DEST_UNREACH] = {
1243 : .handler = icmp_unreach,
1244 : .error = 1,
1245 : },
1246 : [ICMP_SOURCE_QUENCH] = {
1247 : .handler = icmp_unreach,
1248 : .error = 1,
1249 : },
1250 : [ICMP_REDIRECT] = {
1251 : .handler = icmp_redirect,
1252 : .error = 1,
1253 : },
1254 : [6] = {
1255 : .handler = icmp_discard,
1256 : .error = 1,
1257 : },
1258 : [7] = {
1259 : .handler = icmp_discard,
1260 : .error = 1,
1261 : },
1262 : [ICMP_ECHO] = {
1263 : .handler = icmp_echo,
1264 : },
1265 : [9] = {
1266 : .handler = icmp_discard,
1267 : .error = 1,
1268 : },
1269 : [10] = {
1270 : .handler = icmp_discard,
1271 : .error = 1,
1272 : },
1273 : [ICMP_TIME_EXCEEDED] = {
1274 : .handler = icmp_unreach,
1275 : .error = 1,
1276 : },
1277 : [ICMP_PARAMETERPROB] = {
1278 : .handler = icmp_unreach,
1279 : .error = 1,
1280 : },
1281 : [ICMP_TIMESTAMP] = {
1282 : .handler = icmp_timestamp,
1283 : },
1284 : [ICMP_TIMESTAMPREPLY] = {
1285 : .handler = icmp_discard,
1286 : },
1287 : [ICMP_INFO_REQUEST] = {
1288 : .handler = icmp_discard,
1289 : },
1290 : [ICMP_INFO_REPLY] = {
1291 : .handler = icmp_discard,
1292 : },
1293 : [ICMP_ADDRESS] = {
1294 : .handler = icmp_discard,
1295 : },
1296 : [ICMP_ADDRESSREPLY] = {
1297 : .handler = icmp_discard,
1298 : },
1299 : };
1300 :
1301 0 : static void __net_exit icmp_sk_exit(struct net *net)
1302 : {
1303 0 : int i;
1304 :
1305 0 : for_each_possible_cpu(i)
1306 0 : inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.icmp_sk, i));
1307 0 : free_percpu(net->ipv4.icmp_sk);
1308 0 : net->ipv4.icmp_sk = NULL;
1309 0 : }
1310 :
1311 1 : static int __net_init icmp_sk_init(struct net *net)
1312 : {
1313 1 : int i, err;
1314 :
1315 1 : net->ipv4.icmp_sk = alloc_percpu(struct sock *);
1316 1 : if (!net->ipv4.icmp_sk)
1317 : return -ENOMEM;
1318 :
1319 5 : for_each_possible_cpu(i) {
1320 4 : struct sock *sk;
1321 :
1322 4 : err = inet_ctl_sock_create(&sk, PF_INET,
1323 : SOCK_RAW, IPPROTO_ICMP, net);
1324 4 : if (err < 0)
1325 0 : goto fail;
1326 :
1327 4 : *per_cpu_ptr(net->ipv4.icmp_sk, i) = sk;
1328 :
1329 : /* Enough space for 2 64K ICMP packets, including
1330 : * sk_buff/skb_shared_info struct overhead.
1331 : */
1332 4 : sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
1333 :
1334 : /*
1335 : * Speedup sock_wfree()
1336 : */
1337 4 : sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1338 4 : inet_sk(sk)->pmtudisc = IP_PMTUDISC_DONT;
1339 : }
1340 :
1341 : /* Control parameters for ECHO replies. */
1342 1 : net->ipv4.sysctl_icmp_echo_ignore_all = 0;
1343 1 : net->ipv4.sysctl_icmp_echo_ignore_broadcasts = 1;
1344 :
1345 : /* Control parameter - ignore bogus broadcast responses? */
1346 1 : net->ipv4.sysctl_icmp_ignore_bogus_error_responses = 1;
1347 :
1348 : /*
1349 : * Configurable global rate limit.
1350 : *
1351 : * ratelimit defines tokens/packet consumed for dst->rate_token
1352 : * bucket ratemask defines which icmp types are ratelimited by
1353 : * setting it's bit position.
1354 : *
1355 : * default:
1356 : * dest unreachable (3), source quench (4),
1357 : * time exceeded (11), parameter problem (12)
1358 : */
1359 :
1360 1 : net->ipv4.sysctl_icmp_ratelimit = 1 * HZ;
1361 1 : net->ipv4.sysctl_icmp_ratemask = 0x1818;
1362 1 : net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr = 0;
1363 :
1364 1 : return 0;
1365 :
1366 0 : fail:
1367 0 : icmp_sk_exit(net);
1368 0 : return err;
1369 : }
1370 :
1371 : static struct pernet_operations __net_initdata icmp_sk_ops = {
1372 : .init = icmp_sk_init,
1373 : .exit = icmp_sk_exit,
1374 : };
1375 :
1376 1 : int __init icmp_init(void)
1377 : {
1378 1 : return register_pernet_subsys(&icmp_sk_ops);
1379 : }
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