1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * NET3: Implementation of the ICMP protocol layer.
5 * Alan Cox, <alan@lxorguk.ukuu.org.uk>
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.
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
20 * Alan Cox : Added 216,128 byte paths to the MTU
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
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
38 * Thomas Quinot : ICMP Dest Unreach codes up to 15 are
40 * Andi Kleen : Check all packet lengths properly
41 * and moved all kfree_skb() up to
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
51 * Tristan Greaves : Added sysctl option to ignore bogus
52 * broadcast responses from broken routers.
56 * - Should use skb_pull() instead of all the manual checking.
57 * This would also greatly simply some upper layer error handlers. --AK
60 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
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>
77 #include <net/route.h>
78 #include <net/protocol.h>
84 #include <linux/skbuff.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>
92 #include <net/inet_common.h>
93 #include <net/ip_fib.h>
94 #include <net/l3mdev.h>
97 * Build xmit assembly blocks
106 struct icmphdr icmph;
110 struct ip_options_data replyopts;
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'. */
116 const struct icmp_err icmp_err_convert[] = {
118 .errno = ENETUNREACH, /* ICMP_NET_UNREACH */
122 .errno = EHOSTUNREACH, /* ICMP_HOST_UNREACH */
126 .errno = ENOPROTOOPT /* ICMP_PROT_UNREACH */,
130 .errno = ECONNREFUSED, /* ICMP_PORT_UNREACH */
134 .errno = EMSGSIZE, /* ICMP_FRAG_NEEDED */
138 .errno = EOPNOTSUPP, /* ICMP_SR_FAILED */
142 .errno = ENETUNREACH, /* ICMP_NET_UNKNOWN */
146 .errno = EHOSTDOWN, /* ICMP_HOST_UNKNOWN */
150 .errno = ENONET, /* ICMP_HOST_ISOLATED */
154 .errno = ENETUNREACH, /* ICMP_NET_ANO */
158 .errno = EHOSTUNREACH, /* ICMP_HOST_ANO */
162 .errno = ENETUNREACH, /* ICMP_NET_UNR_TOS */
166 .errno = EHOSTUNREACH, /* ICMP_HOST_UNR_TOS */
170 .errno = EHOSTUNREACH, /* ICMP_PKT_FILTERED */
174 .errno = EHOSTUNREACH, /* ICMP_PREC_VIOLATION */
178 .errno = EHOSTUNREACH, /* ICMP_PREC_CUTOFF */
182 EXPORT_SYMBOL(icmp_err_convert);
185 * ICMP control array. This specifies what to do with each ICMP.
188 struct icmp_control {
189 bool (*handler)(struct sk_buff *skb);
190 short error; /* This ICMP is classed as an error message */
193 static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1];
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.
200 * On SMP we have one ICMP socket per-cpu.
202 static struct sock *icmp_sk(struct net *net)
204 return this_cpu_read(*net->ipv4.icmp_sk);
207 /* Called with BH disabled */
208 static inline struct sock *icmp_xmit_lock(struct net *net)
214 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.
223 static inline void icmp_xmit_unlock(struct sock *sk)
225 spin_unlock(&sk->sk_lock.slock);
228 int sysctl_icmp_msgs_per_sec __read_mostly = 1000;
229 int sysctl_icmp_msgs_burst __read_mostly = 50;
236 .lock = __SPIN_LOCK_UNLOCKED(icmp_global.lock),
240 * icmp_global_allow - Are we allowed to send one more ICMP message ?
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
246 bool icmp_global_allow(void)
248 u32 credit, delta, incr = 0, now = (u32)jiffies;
251 /* Check if token bucket is empty and cannot be refilled
252 * without taking the spinlock.
254 if (!icmp_global.credit) {
255 delta = min_t(u32, now - icmp_global.stamp, HZ);
260 spin_lock(&icmp_global.lock);
261 delta = min_t(u32, now - icmp_global.stamp, HZ);
262 if (delta >= HZ / 50) {
263 incr = sysctl_icmp_msgs_per_sec * delta / HZ ;
265 icmp_global.stamp = now;
267 credit = min_t(u32, icmp_global.credit + incr, sysctl_icmp_msgs_burst);
272 icmp_global.credit = credit;
273 spin_unlock(&icmp_global.lock);
276 EXPORT_SYMBOL(icmp_global_allow);
278 static bool icmpv4_mask_allow(struct net *net, int type, int code)
280 if (type > NR_ICMP_TYPES)
283 /* Don't limit PMTU discovery. */
284 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
287 /* Limit if icmp type is enabled in ratemask. */
288 if (!((1 << type) & net->ipv4.sysctl_icmp_ratemask))
294 static bool icmpv4_global_allow(struct net *net, int type, int code)
296 if (icmpv4_mask_allow(net, type, code))
299 if (icmp_global_allow())
306 * Send an ICMP frame.
309 static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
310 struct flowi4 *fl4, int type, int code)
312 struct dst_entry *dst = &rt->dst;
313 struct inet_peer *peer;
317 if (icmpv4_mask_allow(net, type, code))
320 /* No rate limit on loopback */
321 if (dst->dev && (dst->dev->flags&IFF_LOOPBACK))
324 vif = l3mdev_master_ifindex(dst->dev);
325 peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr, vif, 1);
326 rc = inet_peer_xrlim_allow(peer, net->ipv4.sysctl_icmp_ratelimit);
334 * Maintain the counters used in the SNMP statistics for outgoing ICMP
336 void icmp_out_count(struct net *net, unsigned char type)
338 ICMPMSGOUT_INC_STATS(net, type);
339 ICMP_INC_STATS(net, ICMP_MIB_OUTMSGS);
343 * Checksum each fragment, and on the first include the headers and final
346 static int icmp_glue_bits(void *from, char *to, int offset, int len, int odd,
349 struct icmp_bxm *icmp_param = (struct icmp_bxm *)from;
352 csum = skb_copy_and_csum_bits(icmp_param->skb,
353 icmp_param->offset + offset,
356 skb->csum = csum_block_add(skb->csum, csum, odd);
357 if (icmp_pointers[icmp_param->data.icmph.type].error)
358 nf_ct_attach(skb, icmp_param->skb);
362 static void icmp_push_reply(struct icmp_bxm *icmp_param,
364 struct ipcm_cookie *ipc, struct rtable **rt)
369 sk = icmp_sk(dev_net((*rt)->dst.dev));
370 if (ip_append_data(sk, fl4, icmp_glue_bits, icmp_param,
371 icmp_param->data_len+icmp_param->head_len,
372 icmp_param->head_len,
373 ipc, rt, MSG_DONTWAIT) < 0) {
374 __ICMP_INC_STATS(sock_net(sk), ICMP_MIB_OUTERRORS);
375 ip_flush_pending_frames(sk);
376 } else if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) {
377 struct icmphdr *icmph = icmp_hdr(skb);
379 struct sk_buff *skb1;
381 skb_queue_walk(&sk->sk_write_queue, skb1) {
382 csum = csum_add(csum, skb1->csum);
384 csum = csum_partial_copy_nocheck((void *)&icmp_param->data,
386 icmp_param->head_len, csum);
387 icmph->checksum = csum_fold(csum);
388 skb->ip_summed = CHECKSUM_NONE;
389 ip_push_pending_frames(sk, fl4);
394 * Driving logic for building and sending ICMP messages.
397 static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
399 struct ipcm_cookie ipc;
400 struct rtable *rt = skb_rtable(skb);
401 struct net *net = dev_net(rt->dst.dev);
404 struct inet_sock *inet;
406 u32 mark = IP4_REPLY_MARK(net, skb->mark);
407 int type = icmp_param->data.icmph.type;
408 int code = icmp_param->data.icmph.code;
410 if (ip_options_echo(net, &icmp_param->replyopts.opt.opt, skb))
413 /* Needed by both icmp_global_allow and icmp_xmit_lock */
416 /* global icmp_msgs_per_sec */
417 if (!icmpv4_global_allow(net, type, code))
420 sk = icmp_xmit_lock(net);
425 icmp_param->data.icmph.checksum = 0;
428 inet->tos = ip_hdr(skb)->tos;
430 daddr = ipc.addr = ip_hdr(skb)->saddr;
431 saddr = fib_compute_spec_dst(skb);
433 if (icmp_param->replyopts.opt.opt.optlen) {
434 ipc.opt = &icmp_param->replyopts.opt;
435 if (ipc.opt->opt.srr)
436 daddr = icmp_param->replyopts.opt.opt.faddr;
438 memset(&fl4, 0, sizeof(fl4));
441 fl4.flowi4_mark = mark;
442 fl4.flowi4_uid = sock_net_uid(net, NULL);
443 fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);
444 fl4.flowi4_proto = IPPROTO_ICMP;
445 fl4.flowi4_oif = l3mdev_master_ifindex(skb->dev);
446 security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
447 rt = ip_route_output_key(net, &fl4);
450 if (icmpv4_xrlim_allow(net, rt, &fl4, type, code))
451 icmp_push_reply(icmp_param, &fl4, &ipc, &rt);
454 icmp_xmit_unlock(sk);
459 static struct rtable *icmp_route_lookup(struct net *net,
461 struct sk_buff *skb_in,
462 const struct iphdr *iph,
463 __be32 saddr, u8 tos, u32 mark,
465 struct icmp_bxm *param)
467 struct rtable *rt, *rt2;
468 struct flowi4 fl4_dec;
471 memset(fl4, 0, sizeof(*fl4));
472 fl4->daddr = (param->replyopts.opt.opt.srr ?
473 param->replyopts.opt.opt.faddr : iph->saddr);
475 fl4->flowi4_mark = mark;
476 fl4->flowi4_uid = sock_net_uid(net, NULL);
477 fl4->flowi4_tos = RT_TOS(tos);
478 fl4->flowi4_proto = IPPROTO_ICMP;
479 fl4->fl4_icmp_type = type;
480 fl4->fl4_icmp_code = code;
481 fl4->flowi4_oif = l3mdev_master_ifindex(skb_dst(skb_in)->dev);
483 security_skb_classify_flow(skb_in, flowi4_to_flowi(fl4));
484 rt = ip_route_output_key_hash(net, fl4, skb_in);
488 /* No need to clone since we're just using its address. */
491 rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
492 flowi4_to_flowi(fl4), NULL, 0);
496 } else if (PTR_ERR(rt) == -EPERM) {
501 err = xfrm_decode_session_reverse(skb_in, flowi4_to_flowi(&fl4_dec), AF_INET);
503 goto relookup_failed;
505 if (inet_addr_type_dev_table(net, skb_dst(skb_in)->dev,
506 fl4_dec.saddr) == RTN_LOCAL) {
507 rt2 = __ip_route_output_key(net, &fl4_dec);
511 struct flowi4 fl4_2 = {};
512 unsigned long orefdst;
514 fl4_2.daddr = fl4_dec.saddr;
515 rt2 = ip_route_output_key(net, &fl4_2);
518 goto relookup_failed;
521 orefdst = skb_in->_skb_refdst; /* save old refdst */
522 skb_dst_set(skb_in, NULL);
523 err = ip_route_input(skb_in, fl4_dec.daddr, fl4_dec.saddr,
524 RT_TOS(tos), rt2->dst.dev);
526 dst_release(&rt2->dst);
527 rt2 = skb_rtable(skb_in);
528 skb_in->_skb_refdst = orefdst; /* restore old refdst */
532 goto relookup_failed;
534 rt2 = (struct rtable *) xfrm_lookup(net, &rt2->dst,
535 flowi4_to_flowi(&fl4_dec), NULL,
538 dst_release(&rt->dst);
539 memcpy(fl4, &fl4_dec, sizeof(*fl4));
541 } else if (PTR_ERR(rt2) == -EPERM) {
543 dst_release(&rt->dst);
547 goto relookup_failed;
558 * Send an ICMP message in response to a situation
560 * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header.
561 * MAY send more (we do).
562 * MUST NOT change this header information.
563 * MUST NOT reply to a multicast/broadcast IP address.
564 * MUST NOT reply to a multicast/broadcast MAC address.
565 * MUST reply to only the first fragment.
568 void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info,
569 const struct ip_options *opt)
573 struct icmp_bxm icmp_param;
574 struct rtable *rt = skb_rtable(skb_in);
575 struct ipcm_cookie ipc;
587 net = dev_net(rt->dst.dev);
588 else if (skb_in->dev)
589 net = dev_net(skb_in->dev);
594 * Find the original header. It is expected to be valid, of course.
595 * Check this, icmp_send is called from the most obscure devices
598 iph = ip_hdr(skb_in);
600 if ((u8 *)iph < skb_in->head ||
601 (skb_network_header(skb_in) + sizeof(*iph)) >
602 skb_tail_pointer(skb_in))
606 * No replies to physical multicast/broadcast
608 if (skb_in->pkt_type != PACKET_HOST)
612 * Now check at the protocol level
614 if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
618 * Only reply to fragment 0. We byte re-order the constant
619 * mask for efficiency.
621 if (iph->frag_off & htons(IP_OFFSET))
625 * If we send an ICMP error to an ICMP error a mess would result..
627 if (icmp_pointers[type].error) {
629 * We are an error, check if we are replying to an
632 if (iph->protocol == IPPROTO_ICMP) {
633 u8 _inner_type, *itp;
635 itp = skb_header_pointer(skb_in,
636 skb_network_header(skb_in) +
638 offsetof(struct icmphdr,
647 * Assume any unknown ICMP type is an error. This
648 * isn't specified by the RFC, but think about it..
650 if (*itp > NR_ICMP_TYPES ||
651 icmp_pointers[*itp].error)
656 /* Needed by both icmp_global_allow and icmp_xmit_lock */
659 /* Check global sysctl_icmp_msgs_per_sec ratelimit, unless
660 * incoming dev is loopback. If outgoing dev change to not be
661 * loopback, then peer ratelimit still work (in icmpv4_xrlim_allow)
663 if (!(skb_in->dev && (skb_in->dev->flags&IFF_LOOPBACK)) &&
664 !icmpv4_global_allow(net, type, code))
667 sk = icmp_xmit_lock(net);
672 * Construct source address and options.
676 if (!(rt->rt_flags & RTCF_LOCAL)) {
677 struct net_device *dev = NULL;
680 if (rt_is_input_route(rt) &&
681 net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr)
682 dev = dev_get_by_index_rcu(net, inet_iif(skb_in));
685 saddr = inet_select_addr(dev, iph->saddr,
692 tos = icmp_pointers[type].error ? ((iph->tos & IPTOS_TOS_MASK) |
693 IPTOS_PREC_INTERNETCONTROL) :
695 mark = IP4_REPLY_MARK(net, skb_in->mark);
697 if (__ip_options_echo(net, &icmp_param.replyopts.opt.opt, skb_in, opt))
702 * Prepare data for ICMP header.
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;
714 ipc.addr = iph->saddr;
715 ipc.opt = &icmp_param.replyopts.opt;
717 rt = icmp_route_lookup(net, &fl4, skb_in, iph, saddr, tos, mark,
718 type, code, &icmp_param);
722 /* peer icmp_ratelimit */
723 if (!icmpv4_xrlim_allow(net, rt, &fl4, type, code))
726 /* RFC says return as much as we can without exceeding 576 bytes. */
728 room = dst_mtu(&rt->dst);
731 room -= sizeof(struct iphdr) + icmp_param.replyopts.opt.opt.optlen;
732 room -= sizeof(struct icmphdr);
734 icmp_param.data_len = skb_in->len - icmp_param.offset;
735 if (icmp_param.data_len > room)
736 icmp_param.data_len = room;
737 icmp_param.head_len = sizeof(struct icmphdr);
739 icmp_push_reply(&icmp_param, &fl4, &ipc, &rt);
743 icmp_xmit_unlock(sk);
748 EXPORT_SYMBOL(__icmp_send);
751 static void icmp_socket_deliver(struct sk_buff *skb, u32 info)
753 const struct iphdr *iph = (const struct iphdr *) skb->data;
754 const struct net_protocol *ipprot;
755 int protocol = iph->protocol;
757 /* Checkin full IP header plus 8 bytes of protocol to
758 * avoid additional coding at protocol handlers.
760 if (!pskb_may_pull(skb, iph->ihl * 4 + 8)) {
761 __ICMP_INC_STATS(dev_net(skb->dev), ICMP_MIB_INERRORS);
765 raw_icmp_error(skb, protocol, info);
767 ipprot = rcu_dereference(inet_protos[protocol]);
768 if (ipprot && ipprot->err_handler)
769 ipprot->err_handler(skb, info);
772 static bool icmp_tag_validation(int proto)
777 ok = rcu_dereference(inet_protos[proto])->icmp_strict_tag_validation;
783 * Handle ICMP_DEST_UNREACH, ICMP_TIME_EXCEEDED, ICMP_QUENCH, and
784 * ICMP_PARAMETERPROB.
787 static bool icmp_unreach(struct sk_buff *skb)
789 const struct iphdr *iph;
790 struct icmphdr *icmph;
794 net = dev_net(skb_dst(skb)->dev);
797 * Incomplete header ?
798 * Only checks for the IP header, there should be an
799 * additional check for longer headers in upper levels.
802 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
805 icmph = icmp_hdr(skb);
806 iph = (const struct iphdr *)skb->data;
808 if (iph->ihl < 5) /* Mangled header, drop. */
811 switch (icmph->type) {
812 case ICMP_DEST_UNREACH:
813 switch (icmph->code & 15) {
814 case ICMP_NET_UNREACH:
815 case ICMP_HOST_UNREACH:
816 case ICMP_PROT_UNREACH:
817 case ICMP_PORT_UNREACH:
819 case ICMP_FRAG_NEEDED:
820 /* for documentation of the ip_no_pmtu_disc
822 * Documentation/networking/ip-sysctl.txt
824 switch (net->ipv4.sysctl_ip_no_pmtu_disc) {
826 net_dbg_ratelimited("%pI4: fragmentation needed and DF set\n",
832 if (!icmp_tag_validation(iph->protocol))
836 info = ntohs(icmph->un.frag.mtu);
840 net_dbg_ratelimited("%pI4: Source Route Failed\n",
846 if (icmph->code > NR_ICMP_UNREACH)
849 case ICMP_PARAMETERPROB:
850 info = ntohl(icmph->un.gateway) >> 24;
852 case ICMP_TIME_EXCEEDED:
853 __ICMP_INC_STATS(net, ICMP_MIB_INTIMEEXCDS);
854 if (icmph->code == ICMP_EXC_FRAGTIME)
860 * Throw it at our lower layers
862 * RFC 1122: 3.2.2 MUST extract the protocol ID from the passed
864 * RFC 1122: 3.2.2.1 MUST pass ICMP unreach messages to the
866 * RFC 1122: 3.2.2.2 MUST pass ICMP time expired messages to
871 * Check the other end isn't violating RFC 1122. Some routers send
872 * bogus responses to broadcast frames. If you see this message
873 * first check your netmask matches at both ends, if it does then
874 * get the other vendor to fix their kit.
877 if (!net->ipv4.sysctl_icmp_ignore_bogus_error_responses &&
878 inet_addr_type_dev_table(net, skb->dev, iph->daddr) == RTN_BROADCAST) {
879 net_warn_ratelimited("%pI4 sent an invalid ICMP type %u, code %u error to a broadcast: %pI4 on %s\n",
881 icmph->type, icmph->code,
882 &iph->daddr, skb->dev->name);
886 icmp_socket_deliver(skb, info);
891 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
897 * Handle ICMP_REDIRECT.
900 static bool icmp_redirect(struct sk_buff *skb)
902 if (skb->len < sizeof(struct iphdr)) {
903 __ICMP_INC_STATS(dev_net(skb->dev), ICMP_MIB_INERRORS);
907 if (!pskb_may_pull(skb, sizeof(struct iphdr))) {
908 /* there aught to be a stat */
912 icmp_socket_deliver(skb, ntohl(icmp_hdr(skb)->un.gateway));
917 * Handle ICMP_ECHO ("ping") requests.
919 * RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo
921 * RFC 1122: 3.2.2.6 Data received in the ICMP_ECHO request MUST be
922 * included in the reply.
923 * RFC 1812: 4.3.3.6 SHOULD have a config option for silently ignoring
924 * echo requests, MUST have default=NOT.
925 * See also WRT handling of options once they are done and working.
928 static bool icmp_echo(struct sk_buff *skb)
932 net = dev_net(skb_dst(skb)->dev);
933 if (!net->ipv4.sysctl_icmp_echo_ignore_all) {
934 struct icmp_bxm icmp_param;
936 icmp_param.data.icmph = *icmp_hdr(skb);
937 icmp_param.data.icmph.type = ICMP_ECHOREPLY;
938 icmp_param.skb = skb;
939 icmp_param.offset = 0;
940 icmp_param.data_len = skb->len;
941 icmp_param.head_len = sizeof(struct icmphdr);
942 icmp_reply(&icmp_param, skb);
944 /* should there be an ICMP stat for ignored echos? */
949 * Handle ICMP Timestamp requests.
950 * RFC 1122: 3.2.2.8 MAY implement ICMP timestamp requests.
951 * SHOULD be in the kernel for minimum random latency.
952 * MUST be accurate to a few minutes.
953 * MUST be updated at least at 15Hz.
955 static bool icmp_timestamp(struct sk_buff *skb)
957 struct icmp_bxm icmp_param;
965 * Fill in the current time as ms since midnight UT:
967 icmp_param.data.times[1] = inet_current_timestamp();
968 icmp_param.data.times[2] = icmp_param.data.times[1];
970 BUG_ON(skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4));
972 icmp_param.data.icmph = *icmp_hdr(skb);
973 icmp_param.data.icmph.type = ICMP_TIMESTAMPREPLY;
974 icmp_param.data.icmph.code = 0;
975 icmp_param.skb = skb;
976 icmp_param.offset = 0;
977 icmp_param.data_len = 0;
978 icmp_param.head_len = sizeof(struct icmphdr) + 12;
979 icmp_reply(&icmp_param, skb);
983 __ICMP_INC_STATS(dev_net(skb_dst(skb)->dev), ICMP_MIB_INERRORS);
987 static bool icmp_discard(struct sk_buff *skb)
989 /* pretend it was a success */
994 * Deal with incoming ICMP packets.
996 int icmp_rcv(struct sk_buff *skb)
998 struct icmphdr *icmph;
999 struct rtable *rt = skb_rtable(skb);
1000 struct net *net = dev_net(rt->dst.dev);
1003 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1004 struct sec_path *sp = skb_sec_path(skb);
1007 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
1011 if (!pskb_may_pull(skb, sizeof(*icmph) + sizeof(struct iphdr)))
1014 nh = skb_network_offset(skb);
1015 skb_set_network_header(skb, sizeof(*icmph));
1017 if (!xfrm4_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
1020 skb_set_network_header(skb, nh);
1023 __ICMP_INC_STATS(net, ICMP_MIB_INMSGS);
1025 if (skb_checksum_simple_validate(skb))
1028 if (!pskb_pull(skb, sizeof(*icmph)))
1031 icmph = icmp_hdr(skb);
1033 ICMPMSGIN_INC_STATS(net, icmph->type);
1035 * 18 is the highest 'known' ICMP type. Anything else is a mystery
1037 * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
1040 if (icmph->type > NR_ICMP_TYPES)
1045 * Parse the ICMP message
1048 if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
1050 * RFC 1122: 3.2.2.6 An ICMP_ECHO to broadcast MAY be
1051 * silently ignored (we let user decide with a sysctl).
1052 * RFC 1122: 3.2.2.8 An ICMP_TIMESTAMP MAY be silently
1053 * discarded if to broadcast/multicast.
1055 if ((icmph->type == ICMP_ECHO ||
1056 icmph->type == ICMP_TIMESTAMP) &&
1057 net->ipv4.sysctl_icmp_echo_ignore_broadcasts) {
1060 if (icmph->type != ICMP_ECHO &&
1061 icmph->type != ICMP_TIMESTAMP &&
1062 icmph->type != ICMP_ADDRESS &&
1063 icmph->type != ICMP_ADDRESSREPLY) {
1068 success = icmp_pointers[icmph->type].handler(skb);
1072 return NET_RX_SUCCESS;
1079 __ICMP_INC_STATS(net, ICMP_MIB_CSUMERRORS);
1081 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
1085 int icmp_err(struct sk_buff *skb, u32 info)
1087 struct iphdr *iph = (struct iphdr *)skb->data;
1088 int offset = iph->ihl<<2;
1089 struct icmphdr *icmph = (struct icmphdr *)(skb->data + offset);
1090 int type = icmp_hdr(skb)->type;
1091 int code = icmp_hdr(skb)->code;
1092 struct net *net = dev_net(skb->dev);
1095 * Use ping_err to handle all icmp errors except those
1096 * triggered by ICMP_ECHOREPLY which sent from kernel.
1098 if (icmph->type != ICMP_ECHOREPLY) {
1099 ping_err(skb, offset, info);
1103 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
1104 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ICMP);
1105 else if (type == ICMP_REDIRECT)
1106 ipv4_redirect(skb, net, 0, IPPROTO_ICMP);
1112 * This table is the definition of how we handle ICMP.
1114 static const struct icmp_control icmp_pointers[NR_ICMP_TYPES + 1] = {
1115 [ICMP_ECHOREPLY] = {
1116 .handler = ping_rcv,
1119 .handler = icmp_discard,
1123 .handler = icmp_discard,
1126 [ICMP_DEST_UNREACH] = {
1127 .handler = icmp_unreach,
1130 [ICMP_SOURCE_QUENCH] = {
1131 .handler = icmp_unreach,
1135 .handler = icmp_redirect,
1139 .handler = icmp_discard,
1143 .handler = icmp_discard,
1147 .handler = icmp_echo,
1150 .handler = icmp_discard,
1154 .handler = icmp_discard,
1157 [ICMP_TIME_EXCEEDED] = {
1158 .handler = icmp_unreach,
1161 [ICMP_PARAMETERPROB] = {
1162 .handler = icmp_unreach,
1165 [ICMP_TIMESTAMP] = {
1166 .handler = icmp_timestamp,
1168 [ICMP_TIMESTAMPREPLY] = {
1169 .handler = icmp_discard,
1171 [ICMP_INFO_REQUEST] = {
1172 .handler = icmp_discard,
1174 [ICMP_INFO_REPLY] = {
1175 .handler = icmp_discard,
1178 .handler = icmp_discard,
1180 [ICMP_ADDRESSREPLY] = {
1181 .handler = icmp_discard,
1185 static void __net_exit icmp_sk_exit(struct net *net)
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;
1195 static int __net_init icmp_sk_init(struct net *net)
1199 net->ipv4.icmp_sk = alloc_percpu(struct sock *);
1200 if (!net->ipv4.icmp_sk)
1203 for_each_possible_cpu(i) {
1206 err = inet_ctl_sock_create(&sk, PF_INET,
1207 SOCK_RAW, IPPROTO_ICMP, net);
1211 *per_cpu_ptr(net->ipv4.icmp_sk, i) = sk;
1213 /* Enough space for 2 64K ICMP packets, including
1214 * sk_buff/skb_shared_info struct overhead.
1216 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
1219 * Speedup sock_wfree()
1221 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1222 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DONT;
1225 /* Control parameters for ECHO replies. */
1226 net->ipv4.sysctl_icmp_echo_ignore_all = 0;
1227 net->ipv4.sysctl_icmp_echo_ignore_broadcasts = 1;
1229 /* Control parameter - ignore bogus broadcast responses? */
1230 net->ipv4.sysctl_icmp_ignore_bogus_error_responses = 1;
1233 * Configurable global rate limit.
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.
1240 * dest unreachable (3), source quench (4),
1241 * time exceeded (11), parameter problem (12)
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;
1255 static struct pernet_operations __net_initdata icmp_sk_ops = {
1256 .init = icmp_sk_init,
1257 .exit = icmp_sk_exit,
1260 int __init icmp_init(void)
1262 return register_pernet_subsys(&icmp_sk_ops);