2 * NET3: Implementation of the ICMP protocol layer.
4 * Alan Cox, <alan@redhat.com>
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.
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.
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
24 * Alan Cox : Added 216,128 byte paths to the MTU
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
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
42 * Thomas Quinot : ICMP Dest Unreach codes up to 15 are
44 * Andi Kleen : Check all packet lengths properly
45 * and moved all kfree_skb() up to
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
55 * Tristan Greaves : Added sysctl option to ignore bogus
56 * broadcast responses from broken routers.
60 * - Should use skb_pull() instead of all the manual checking.
61 * This would also greatly simply some upper layer error handlers. --AK
65 #include <linux/module.h>
66 #include <linux/types.h>
67 #include <linux/jiffies.h>
68 #include <linux/kernel.h>
69 #include <linux/fcntl.h>
70 #include <linux/socket.h>
72 #include <linux/inet.h>
73 #include <linux/inetdevice.h>
74 #include <linux/netdevice.h>
75 #include <linux/string.h>
76 #include <linux/netfilter_ipv4.h>
79 #include <net/route.h>
80 #include <net/protocol.h>
85 #include <linux/skbuff.h>
87 #include <linux/errno.h>
88 #include <linux/timer.h>
89 #include <linux/init.h>
90 #include <asm/system.h>
91 #include <asm/uaccess.h>
92 #include <net/checksum.h>
94 #include <net/inet_common.h>
97 * Build xmit assembly blocks
106 struct icmphdr icmph;
110 struct ip_options replyopts;
111 unsigned char optbuf[40];
117 DEFINE_SNMP_STAT(struct icmpmsg_mib, icmpmsg_statistics) __read_mostly;
119 /* An array of errno for error messages from dest unreach. */
120 /* RFC 1122: 3.2.2.1 States that NET_UNREACH, HOST_UNREACH and SR_FAILED MUST be considered 'transient errs'. */
122 struct icmp_err icmp_err_convert[] = {
124 .errno = ENETUNREACH, /* ICMP_NET_UNREACH */
128 .errno = EHOSTUNREACH, /* ICMP_HOST_UNREACH */
132 .errno = ENOPROTOOPT /* ICMP_PROT_UNREACH */,
136 .errno = ECONNREFUSED, /* ICMP_PORT_UNREACH */
140 .errno = EMSGSIZE, /* ICMP_FRAG_NEEDED */
144 .errno = EOPNOTSUPP, /* ICMP_SR_FAILED */
148 .errno = ENETUNREACH, /* ICMP_NET_UNKNOWN */
152 .errno = EHOSTDOWN, /* ICMP_HOST_UNKNOWN */
156 .errno = ENONET, /* ICMP_HOST_ISOLATED */
160 .errno = ENETUNREACH, /* ICMP_NET_ANO */
164 .errno = EHOSTUNREACH, /* ICMP_HOST_ANO */
168 .errno = ENETUNREACH, /* ICMP_NET_UNR_TOS */
172 .errno = EHOSTUNREACH, /* ICMP_HOST_UNR_TOS */
176 .errno = EHOSTUNREACH, /* ICMP_PKT_FILTERED */
180 .errno = EHOSTUNREACH, /* ICMP_PREC_VIOLATION */
184 .errno = EHOSTUNREACH, /* ICMP_PREC_CUTOFF */
190 * ICMP control array. This specifies what to do with each ICMP.
193 struct icmp_control {
194 void (*handler)(struct sk_buff *skb);
195 short error; /* This ICMP is classed as an error message */
198 static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1];
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.
205 * On SMP we have one ICMP socket per-cpu.
207 static struct sock *icmp_sk(struct net *net)
209 return net->ipv4.icmp_sk[smp_processor_id()];
212 static inline int icmp_xmit_lock(struct sock *sk)
216 if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
217 /* This can happen if the output path signals a
218 * dst_link_failure() for an outgoing ICMP packet.
226 static inline void icmp_xmit_unlock(struct sock *sk)
228 spin_unlock_bh(&sk->sk_lock.slock);
232 * Send an ICMP frame.
236 * Check transmit rate limitation for given message.
237 * The rate information is held in the destination cache now.
238 * This function is generic and could be used for other purposes
239 * too. It uses a Token bucket filter as suggested by Alexey Kuznetsov.
241 * Note that the same dst_entry fields are modified by functions in
242 * route.c too, but these work for packet destinations while xrlim_allow
243 * works for icmp destinations. This means the rate limiting information
244 * for one "ip object" is shared - and these ICMPs are twice limited:
245 * by source and by destination.
247 * RFC 1812: 4.3.2.8 SHOULD be able to limit error message rate
248 * SHOULD allow setting of rate limits
250 * Shared between ICMPv4 and ICMPv6.
252 #define XRLIM_BURST_FACTOR 6
253 int xrlim_allow(struct dst_entry *dst, int timeout)
255 unsigned long now, token = dst->rate_tokens;
259 token += now - dst->rate_last;
260 dst->rate_last = now;
261 if (token > XRLIM_BURST_FACTOR * timeout)
262 token = XRLIM_BURST_FACTOR * timeout;
263 if (token >= timeout) {
267 dst->rate_tokens = token;
271 static inline int icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
274 struct dst_entry *dst = &rt->u.dst;
277 if (type > NR_ICMP_TYPES)
280 /* Don't limit PMTU discovery. */
281 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
284 /* No rate limit on loopback */
285 if (dst->dev && (dst->dev->flags&IFF_LOOPBACK))
288 /* Limit if icmp type is enabled in ratemask. */
289 if ((1 << type) & net->ipv4.sysctl_icmp_ratemask)
290 rc = xrlim_allow(dst, net->ipv4.sysctl_icmp_ratelimit);
296 * Maintain the counters used in the SNMP statistics for outgoing ICMP
298 void icmp_out_count(struct net *net, unsigned char type)
300 ICMPMSGOUT_INC_STATS(net, type);
301 ICMP_INC_STATS(net, ICMP_MIB_OUTMSGS);
305 * Checksum each fragment, and on the first include the headers and final
308 static int icmp_glue_bits(void *from, char *to, int offset, int len, int odd,
311 struct icmp_bxm *icmp_param = (struct icmp_bxm *)from;
314 csum = skb_copy_and_csum_bits(icmp_param->skb,
315 icmp_param->offset + offset,
318 skb->csum = csum_block_add(skb->csum, csum, odd);
319 if (icmp_pointers[icmp_param->data.icmph.type].error)
320 nf_ct_attach(skb, icmp_param->skb);
324 static void icmp_push_reply(struct icmp_bxm *icmp_param,
325 struct ipcm_cookie *ipc, struct rtable *rt)
330 sk = icmp_sk(dev_net(rt->u.dst.dev));
331 if (ip_append_data(sk, icmp_glue_bits, icmp_param,
332 icmp_param->data_len+icmp_param->head_len,
333 icmp_param->head_len,
334 ipc, rt, MSG_DONTWAIT) < 0)
335 ip_flush_pending_frames(sk);
336 else if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) {
337 struct icmphdr *icmph = icmp_hdr(skb);
339 struct sk_buff *skb1;
341 skb_queue_walk(&sk->sk_write_queue, skb1) {
342 csum = csum_add(csum, skb1->csum);
344 csum = csum_partial_copy_nocheck((void *)&icmp_param->data,
346 icmp_param->head_len, csum);
347 icmph->checksum = csum_fold(csum);
348 skb->ip_summed = CHECKSUM_NONE;
349 ip_push_pending_frames(sk);
354 * Driving logic for building and sending ICMP messages.
357 static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
359 struct ipcm_cookie ipc;
360 struct rtable *rt = skb->rtable;
361 struct net *net = dev_net(rt->u.dst.dev);
362 struct sock *sk = icmp_sk(net);
363 struct inet_sock *inet = inet_sk(sk);
366 if (ip_options_echo(&icmp_param->replyopts, skb))
369 if (icmp_xmit_lock(sk))
372 icmp_param->data.icmph.checksum = 0;
374 inet->tos = ip_hdr(skb)->tos;
375 daddr = ipc.addr = rt->rt_src;
377 if (icmp_param->replyopts.optlen) {
378 ipc.opt = &icmp_param->replyopts;
380 daddr = icmp_param->replyopts.faddr;
383 struct flowi fl = { .nl_u = { .ip4_u =
385 .saddr = rt->rt_spec_dst,
386 .tos = RT_TOS(ip_hdr(skb)->tos) } },
387 .proto = IPPROTO_ICMP };
388 security_skb_classify_flow(skb, &fl);
389 if (ip_route_output_key(net, &rt, &fl))
392 if (icmpv4_xrlim_allow(net, rt, icmp_param->data.icmph.type,
393 icmp_param->data.icmph.code))
394 icmp_push_reply(icmp_param, &ipc, rt);
397 icmp_xmit_unlock(sk);
402 * Send an ICMP message in response to a situation
404 * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header.
405 * MAY send more (we do).
406 * MUST NOT change this header information.
407 * MUST NOT reply to a multicast/broadcast IP address.
408 * MUST NOT reply to a multicast/broadcast MAC address.
409 * MUST reply to only the first fragment.
412 void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
416 struct icmp_bxm icmp_param;
417 struct rtable *rt = skb_in->rtable;
418 struct ipcm_cookie ipc;
426 net = dev_net(rt->u.dst.dev);
430 * Find the original header. It is expected to be valid, of course.
431 * Check this, icmp_send is called from the most obscure devices
434 iph = ip_hdr(skb_in);
436 if ((u8 *)iph < skb_in->head ||
437 (skb_in->network_header + sizeof(*iph)) > skb_in->tail)
441 * No replies to physical multicast/broadcast
443 if (skb_in->pkt_type != PACKET_HOST)
447 * Now check at the protocol level
449 if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
453 * Only reply to fragment 0. We byte re-order the constant
454 * mask for efficiency.
456 if (iph->frag_off & htons(IP_OFFSET))
460 * If we send an ICMP error to an ICMP error a mess would result..
462 if (icmp_pointers[type].error) {
464 * We are an error, check if we are replying to an
467 if (iph->protocol == IPPROTO_ICMP) {
468 u8 _inner_type, *itp;
470 itp = skb_header_pointer(skb_in,
471 skb_network_header(skb_in) +
473 offsetof(struct icmphdr,
482 * Assume any unknown ICMP type is an error. This
483 * isn't specified by the RFC, but think about it..
485 if (*itp > NR_ICMP_TYPES ||
486 icmp_pointers[*itp].error)
491 if (icmp_xmit_lock(sk))
495 * Construct source address and options.
499 if (!(rt->rt_flags & RTCF_LOCAL)) {
500 struct net_device *dev = NULL;
503 net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr)
504 dev = dev_get_by_index(net, rt->fl.iif);
507 saddr = inet_select_addr(dev, 0, RT_SCOPE_LINK);
513 tos = icmp_pointers[type].error ? ((iph->tos & IPTOS_TOS_MASK) |
514 IPTOS_PREC_INTERNETCONTROL) :
517 if (ip_options_echo(&icmp_param.replyopts, skb_in))
522 * Prepare data for ICMP header.
525 icmp_param.data.icmph.type = type;
526 icmp_param.data.icmph.code = code;
527 icmp_param.data.icmph.un.gateway = info;
528 icmp_param.data.icmph.checksum = 0;
529 icmp_param.skb = skb_in;
530 icmp_param.offset = skb_network_offset(skb_in);
531 inet_sk(sk)->tos = tos;
532 ipc.addr = iph->saddr;
533 ipc.opt = &icmp_param.replyopts;
539 .daddr = icmp_param.replyopts.srr ?
540 icmp_param.replyopts.faddr :
546 .proto = IPPROTO_ICMP,
557 security_skb_classify_flow(skb_in, &fl);
558 if (__ip_route_output_key(net, &rt, &fl))
561 /* No need to clone since we're just using its address. */
564 err = xfrm_lookup((struct dst_entry **)&rt, &fl, NULL, 0);
577 if (xfrm_decode_session_reverse(skb_in, &fl, AF_INET))
578 goto relookup_failed;
580 if (inet_addr_type(net, fl.fl4_src) == RTN_LOCAL)
581 err = __ip_route_output_key(net, &rt2, &fl);
583 struct flowi fl2 = {};
584 struct dst_entry *odst;
586 fl2.fl4_dst = fl.fl4_src;
587 if (ip_route_output_key(net, &rt2, &fl2))
588 goto relookup_failed;
592 err = ip_route_input(skb_in, fl.fl4_dst, fl.fl4_src,
593 RT_TOS(tos), rt2->u.dst.dev);
595 dst_release(&rt2->u.dst);
596 rt2 = skb_in->rtable;
601 goto relookup_failed;
603 err = xfrm_lookup((struct dst_entry **)&rt2, &fl, NULL,
607 dst_release(&rt->u.dst);
621 if (!icmpv4_xrlim_allow(net, rt, type, code))
624 /* RFC says return as much as we can without exceeding 576 bytes. */
626 room = dst_mtu(&rt->u.dst);
629 room -= sizeof(struct iphdr) + icmp_param.replyopts.optlen;
630 room -= sizeof(struct icmphdr);
632 icmp_param.data_len = skb_in->len - icmp_param.offset;
633 if (icmp_param.data_len > room)
634 icmp_param.data_len = room;
635 icmp_param.head_len = sizeof(struct icmphdr);
637 icmp_push_reply(&icmp_param, &ipc, rt);
641 icmp_xmit_unlock(sk);
647 * Handle ICMP_DEST_UNREACH, ICMP_TIME_EXCEED, and ICMP_QUENCH.
650 static void icmp_unreach(struct sk_buff *skb)
653 struct icmphdr *icmph;
655 struct net_protocol *ipprot;
659 net = dev_net(skb->dst->dev);
662 * Incomplete header ?
663 * Only checks for the IP header, there should be an
664 * additional check for longer headers in upper levels.
667 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
670 icmph = icmp_hdr(skb);
671 iph = (struct iphdr *)skb->data;
673 if (iph->ihl < 5) /* Mangled header, drop. */
676 if (icmph->type == ICMP_DEST_UNREACH) {
677 switch (icmph->code & 15) {
678 case ICMP_NET_UNREACH:
679 case ICMP_HOST_UNREACH:
680 case ICMP_PROT_UNREACH:
681 case ICMP_PORT_UNREACH:
683 case ICMP_FRAG_NEEDED:
684 if (ipv4_config.no_pmtu_disc) {
685 LIMIT_NETDEBUG(KERN_INFO "ICMP: " NIPQUAD_FMT ": "
686 "fragmentation needed "
688 NIPQUAD(iph->daddr));
690 info = ip_rt_frag_needed(net, iph,
691 ntohs(icmph->un.frag.mtu),
698 LIMIT_NETDEBUG(KERN_INFO "ICMP: " NIPQUAD_FMT ": Source "
700 NIPQUAD(iph->daddr));
705 if (icmph->code > NR_ICMP_UNREACH)
707 } else if (icmph->type == ICMP_PARAMETERPROB)
708 info = ntohl(icmph->un.gateway) >> 24;
711 * Throw it at our lower layers
713 * RFC 1122: 3.2.2 MUST extract the protocol ID from the passed
715 * RFC 1122: 3.2.2.1 MUST pass ICMP unreach messages to the
717 * RFC 1122: 3.2.2.2 MUST pass ICMP time expired messages to
722 * Check the other end isnt violating RFC 1122. Some routers send
723 * bogus responses to broadcast frames. If you see this message
724 * first check your netmask matches at both ends, if it does then
725 * get the other vendor to fix their kit.
728 if (!net->ipv4.sysctl_icmp_ignore_bogus_error_responses &&
729 inet_addr_type(net, iph->daddr) == RTN_BROADCAST) {
731 printk(KERN_WARNING NIPQUAD_FMT " sent an invalid ICMP "
733 "error to a broadcast: " NIPQUAD_FMT " on %s\n",
734 NIPQUAD(ip_hdr(skb)->saddr),
735 icmph->type, icmph->code,
741 /* Checkin full IP header plus 8 bytes of protocol to
742 * avoid additional coding at protocol handlers.
744 if (!pskb_may_pull(skb, iph->ihl * 4 + 8))
747 iph = (struct iphdr *)skb->data;
748 protocol = iph->protocol;
751 * Deliver ICMP message to raw sockets. Pretty useless feature?
753 raw_icmp_error(skb, protocol, info);
755 hash = protocol & (MAX_INET_PROTOS - 1);
757 ipprot = rcu_dereference(inet_protos[hash]);
758 if (ipprot && ipprot->err_handler)
759 ipprot->err_handler(skb, info);
765 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
771 * Handle ICMP_REDIRECT.
774 static void icmp_redirect(struct sk_buff *skb)
778 if (skb->len < sizeof(struct iphdr))
782 * Get the copied header of the packet that caused the redirect
784 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
787 iph = (struct iphdr *)skb->data;
789 switch (icmp_hdr(skb)->code & 7) {
791 case ICMP_REDIR_NETTOS:
793 * As per RFC recommendations now handle it as a host redirect.
795 case ICMP_REDIR_HOST:
796 case ICMP_REDIR_HOSTTOS:
797 ip_rt_redirect(ip_hdr(skb)->saddr, iph->daddr,
798 icmp_hdr(skb)->un.gateway,
799 iph->saddr, skb->dev);
805 ICMP_INC_STATS_BH(dev_net(skb->dev), ICMP_MIB_INERRORS);
810 * Handle ICMP_ECHO ("ping") requests.
812 * RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo
814 * RFC 1122: 3.2.2.6 Data received in the ICMP_ECHO request MUST be
815 * included in the reply.
816 * RFC 1812: 4.3.3.6 SHOULD have a config option for silently ignoring
817 * echo requests, MUST have default=NOT.
818 * See also WRT handling of options once they are done and working.
821 static void icmp_echo(struct sk_buff *skb)
825 net = dev_net(skb->dst->dev);
826 if (!net->ipv4.sysctl_icmp_echo_ignore_all) {
827 struct icmp_bxm icmp_param;
829 icmp_param.data.icmph = *icmp_hdr(skb);
830 icmp_param.data.icmph.type = ICMP_ECHOREPLY;
831 icmp_param.skb = skb;
832 icmp_param.offset = 0;
833 icmp_param.data_len = skb->len;
834 icmp_param.head_len = sizeof(struct icmphdr);
835 icmp_reply(&icmp_param, skb);
840 * Handle ICMP Timestamp requests.
841 * RFC 1122: 3.2.2.8 MAY implement ICMP timestamp requests.
842 * SHOULD be in the kernel for minimum random latency.
843 * MUST be accurate to a few minutes.
844 * MUST be updated at least at 15Hz.
846 static void icmp_timestamp(struct sk_buff *skb)
849 struct icmp_bxm icmp_param;
857 * Fill in the current time as ms since midnight UT:
860 icmp_param.data.times[1] = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC +
861 tv.tv_nsec / NSEC_PER_MSEC);
862 icmp_param.data.times[2] = icmp_param.data.times[1];
863 if (skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4))
865 icmp_param.data.icmph = *icmp_hdr(skb);
866 icmp_param.data.icmph.type = ICMP_TIMESTAMPREPLY;
867 icmp_param.data.icmph.code = 0;
868 icmp_param.skb = skb;
869 icmp_param.offset = 0;
870 icmp_param.data_len = 0;
871 icmp_param.head_len = sizeof(struct icmphdr) + 12;
872 icmp_reply(&icmp_param, skb);
876 ICMP_INC_STATS_BH(dev_net(skb->dst->dev), ICMP_MIB_INERRORS);
882 * Handle ICMP_ADDRESS_MASK requests. (RFC950)
884 * RFC1122 (3.2.2.9). A host MUST only send replies to
885 * ADDRESS_MASK requests if it's been configured as an address mask
886 * agent. Receiving a request doesn't constitute implicit permission to
887 * act as one. Of course, implementing this correctly requires (SHOULD)
888 * a way to turn the functionality on and off. Another one for sysctl(),
891 * RFC1812 (4.3.3.9). A router MUST implement it.
892 * A router SHOULD have switch turning it on/off.
893 * This switch MUST be ON by default.
895 * Gratuitous replies, zero-source replies are not implemented,
896 * that complies with RFC. DO NOT implement them!!! All the idea
897 * of broadcast addrmask replies as specified in RFC950 is broken.
898 * The problem is that it is not uncommon to have several prefixes
899 * on one physical interface. Moreover, addrmask agent can even be
900 * not aware of existing another prefixes.
901 * If source is zero, addrmask agent cannot choose correct prefix.
902 * Gratuitous mask announcements suffer from the same problem.
903 * RFC1812 explains it, but still allows to use ADDRMASK,
904 * that is pretty silly. --ANK
906 * All these rules are so bizarre, that I removed kernel addrmask
907 * support at all. It is wrong, it is obsolete, nobody uses it in
910 * Furthermore you can do it with a usermode address agent program
914 static void icmp_address(struct sk_buff *skb)
918 printk(KERN_DEBUG "a guy asks for address mask. Who is it?\n");
923 * RFC1812 (4.3.3.9). A router SHOULD listen all replies, and complain
924 * loudly if an inconsistency is found.
927 static void icmp_address_reply(struct sk_buff *skb)
929 struct rtable *rt = skb->rtable;
930 struct net_device *dev = skb->dev;
931 struct in_device *in_dev;
932 struct in_ifaddr *ifa;
934 if (skb->len < 4 || !(rt->rt_flags&RTCF_DIRECTSRC))
937 in_dev = in_dev_get(dev);
941 if (in_dev->ifa_list &&
942 IN_DEV_LOG_MARTIANS(in_dev) &&
943 IN_DEV_FORWARD(in_dev)) {
946 mp = skb_header_pointer(skb, 0, sizeof(_mask), &_mask);
948 for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) {
949 if (*mp == ifa->ifa_mask &&
950 inet_ifa_match(rt->rt_src, ifa))
953 if (!ifa && net_ratelimit()) {
954 printk(KERN_INFO "Wrong address mask " NIPQUAD_FMT " from "
955 "%s/" NIPQUAD_FMT "\n",
956 NIPQUAD(*mp), dev->name, NIPQUAD(rt->rt_src));
964 static void icmp_discard(struct sk_buff *skb)
969 * Deal with incoming ICMP packets.
971 int icmp_rcv(struct sk_buff *skb)
973 struct icmphdr *icmph;
974 struct rtable *rt = skb->rtable;
975 struct net *net = dev_net(rt->u.dst.dev);
977 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
980 if (!(skb->sp && skb->sp->xvec[skb->sp->len - 1]->props.flags &
984 if (!pskb_may_pull(skb, sizeof(*icmph) + sizeof(struct iphdr)))
987 nh = skb_network_offset(skb);
988 skb_set_network_header(skb, sizeof(*icmph));
990 if (!xfrm4_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
993 skb_set_network_header(skb, nh);
996 ICMP_INC_STATS_BH(net, ICMP_MIB_INMSGS);
998 switch (skb->ip_summed) {
999 case CHECKSUM_COMPLETE:
1000 if (!csum_fold(skb->csum))
1005 if (__skb_checksum_complete(skb))
1009 if (!pskb_pull(skb, sizeof(*icmph)))
1012 icmph = icmp_hdr(skb);
1014 ICMPMSGIN_INC_STATS_BH(net, icmph->type);
1016 * 18 is the highest 'known' ICMP type. Anything else is a mystery
1018 * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
1021 if (icmph->type > NR_ICMP_TYPES)
1026 * Parse the ICMP message
1029 if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
1031 * RFC 1122: 3.2.2.6 An ICMP_ECHO to broadcast MAY be
1032 * silently ignored (we let user decide with a sysctl).
1033 * RFC 1122: 3.2.2.8 An ICMP_TIMESTAMP MAY be silently
1034 * discarded if to broadcast/multicast.
1036 if ((icmph->type == ICMP_ECHO ||
1037 icmph->type == ICMP_TIMESTAMP) &&
1038 net->ipv4.sysctl_icmp_echo_ignore_broadcasts) {
1041 if (icmph->type != ICMP_ECHO &&
1042 icmph->type != ICMP_TIMESTAMP &&
1043 icmph->type != ICMP_ADDRESS &&
1044 icmph->type != ICMP_ADDRESSREPLY) {
1049 icmp_pointers[icmph->type].handler(skb);
1055 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
1060 * This table is the definition of how we handle ICMP.
1062 static const struct icmp_control icmp_pointers[NR_ICMP_TYPES + 1] = {
1063 [ICMP_ECHOREPLY] = {
1064 .handler = icmp_discard,
1067 .handler = icmp_discard,
1071 .handler = icmp_discard,
1074 [ICMP_DEST_UNREACH] = {
1075 .handler = icmp_unreach,
1078 [ICMP_SOURCE_QUENCH] = {
1079 .handler = icmp_unreach,
1083 .handler = icmp_redirect,
1087 .handler = icmp_discard,
1091 .handler = icmp_discard,
1095 .handler = icmp_echo,
1098 .handler = icmp_discard,
1102 .handler = icmp_discard,
1105 [ICMP_TIME_EXCEEDED] = {
1106 .handler = icmp_unreach,
1109 [ICMP_PARAMETERPROB] = {
1110 .handler = icmp_unreach,
1113 [ICMP_TIMESTAMP] = {
1114 .handler = icmp_timestamp,
1116 [ICMP_TIMESTAMPREPLY] = {
1117 .handler = icmp_discard,
1119 [ICMP_INFO_REQUEST] = {
1120 .handler = icmp_discard,
1122 [ICMP_INFO_REPLY] = {
1123 .handler = icmp_discard,
1126 .handler = icmp_address,
1128 [ICMP_ADDRESSREPLY] = {
1129 .handler = icmp_address_reply,
1133 static void __net_exit icmp_sk_exit(struct net *net)
1137 for_each_possible_cpu(i)
1138 inet_ctl_sock_destroy(net->ipv4.icmp_sk[i]);
1139 kfree(net->ipv4.icmp_sk);
1140 net->ipv4.icmp_sk = NULL;
1143 static int __net_init icmp_sk_init(struct net *net)
1148 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL);
1149 if (net->ipv4.icmp_sk == NULL)
1152 for_each_possible_cpu(i) {
1155 err = inet_ctl_sock_create(&sk, PF_INET,
1156 SOCK_RAW, IPPROTO_ICMP, net);
1160 net->ipv4.icmp_sk[i] = sk;
1162 /* Enough space for 2 64K ICMP packets, including
1163 * sk_buff struct overhead.
1166 (2 * ((64 * 1024) + sizeof(struct sk_buff)));
1168 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DONT;
1171 /* Control parameters for ECHO replies. */
1172 net->ipv4.sysctl_icmp_echo_ignore_all = 0;
1173 net->ipv4.sysctl_icmp_echo_ignore_broadcasts = 1;
1175 /* Control parameter - ignore bogus broadcast responses? */
1176 net->ipv4.sysctl_icmp_ignore_bogus_error_responses = 1;
1179 * Configurable global rate limit.
1181 * ratelimit defines tokens/packet consumed for dst->rate_token
1182 * bucket ratemask defines which icmp types are ratelimited by
1183 * setting it's bit position.
1186 * dest unreachable (3), source quench (4),
1187 * time exceeded (11), parameter problem (12)
1190 net->ipv4.sysctl_icmp_ratelimit = 1 * HZ;
1191 net->ipv4.sysctl_icmp_ratemask = 0x1818;
1192 net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr = 0;
1197 for_each_possible_cpu(i)
1198 inet_ctl_sock_destroy(net->ipv4.icmp_sk[i]);
1199 kfree(net->ipv4.icmp_sk);
1203 static struct pernet_operations __net_initdata icmp_sk_ops = {
1204 .init = icmp_sk_init,
1205 .exit = icmp_sk_exit,
1208 int __init icmp_init(void)
1210 return register_pernet_device(&icmp_sk_ops);
1213 EXPORT_SYMBOL(icmp_err_convert);
1214 EXPORT_SYMBOL(icmp_send);
1215 EXPORT_SYMBOL(xrlim_allow);