2 * NET3: Implementation of the ICMP protocol layer.
4 * Alan Cox, <alan@lxorguk.ukuu.org.uk>
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>
77 #include <linux/slab.h>
80 #include <net/route.h>
81 #include <net/protocol.h>
86 #include <linux/skbuff.h>
88 #include <linux/errno.h>
89 #include <linux/timer.h>
90 #include <linux/init.h>
91 #include <asm/system.h>
92 #include <asm/uaccess.h>
93 #include <net/checksum.h>
95 #include <net/inet_common.h>
98 * Build xmit assembly blocks
107 struct icmphdr icmph;
111 struct ip_options replyopts;
112 unsigned char optbuf[40];
115 /* An array of errno for error messages from dest unreach. */
116 /* RFC 1122: 3.2.2.1 States that NET_UNREACH, HOST_UNREACH and SR_FAILED MUST be considered 'transient errs'. */
118 const struct icmp_err icmp_err_convert[] = {
120 .errno = ENETUNREACH, /* ICMP_NET_UNREACH */
124 .errno = EHOSTUNREACH, /* ICMP_HOST_UNREACH */
128 .errno = ENOPROTOOPT /* ICMP_PROT_UNREACH */,
132 .errno = ECONNREFUSED, /* ICMP_PORT_UNREACH */
136 .errno = EMSGSIZE, /* ICMP_FRAG_NEEDED */
140 .errno = EOPNOTSUPP, /* ICMP_SR_FAILED */
144 .errno = ENETUNREACH, /* ICMP_NET_UNKNOWN */
148 .errno = EHOSTDOWN, /* ICMP_HOST_UNKNOWN */
152 .errno = ENONET, /* ICMP_HOST_ISOLATED */
156 .errno = ENETUNREACH, /* ICMP_NET_ANO */
160 .errno = EHOSTUNREACH, /* ICMP_HOST_ANO */
164 .errno = ENETUNREACH, /* ICMP_NET_UNR_TOS */
168 .errno = EHOSTUNREACH, /* ICMP_HOST_UNR_TOS */
172 .errno = EHOSTUNREACH, /* ICMP_PKT_FILTERED */
176 .errno = EHOSTUNREACH, /* ICMP_PREC_VIOLATION */
180 .errno = EHOSTUNREACH, /* ICMP_PREC_CUTOFF */
184 EXPORT_SYMBOL(icmp_err_convert);
187 * ICMP control array. This specifies what to do with each ICMP.
190 struct icmp_control {
191 void (*handler)(struct sk_buff *skb);
192 short error; /* This ICMP is classed as an error message */
195 static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1];
198 * The ICMP socket(s). This is the most convenient way to flow control
199 * our ICMP output as well as maintain a clean interface throughout
200 * all layers. All Socketless IP sends will soon be gone.
202 * On SMP we have one ICMP socket per-cpu.
204 static struct sock *icmp_sk(struct net *net)
206 return net->ipv4.icmp_sk[smp_processor_id()];
209 static inline struct sock *icmp_xmit_lock(struct net *net)
217 if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
218 /* This can happen if the output path signals a
219 * dst_link_failure() for an outgoing ICMP packet.
227 static inline void icmp_xmit_unlock(struct sock *sk)
229 spin_unlock_bh(&sk->sk_lock.slock);
233 * Send an ICMP frame.
236 static inline bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
239 struct dst_entry *dst = &rt->dst;
242 if (type > NR_ICMP_TYPES)
245 /* Don't limit PMTU discovery. */
246 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
249 /* No rate limit on loopback */
250 if (dst->dev && (dst->dev->flags&IFF_LOOPBACK))
253 /* Limit if icmp type is enabled in ratemask. */
254 if ((1 << type) & net->ipv4.sysctl_icmp_ratemask) {
257 rc = inet_peer_xrlim_allow(rt->peer,
258 net->ipv4.sysctl_icmp_ratelimit);
265 * Maintain the counters used in the SNMP statistics for outgoing ICMP
267 void icmp_out_count(struct net *net, unsigned char type)
269 ICMPMSGOUT_INC_STATS(net, type);
270 ICMP_INC_STATS(net, ICMP_MIB_OUTMSGS);
274 * Checksum each fragment, and on the first include the headers and final
277 static int icmp_glue_bits(void *from, char *to, int offset, int len, int odd,
280 struct icmp_bxm *icmp_param = (struct icmp_bxm *)from;
283 csum = skb_copy_and_csum_bits(icmp_param->skb,
284 icmp_param->offset + offset,
287 skb->csum = csum_block_add(skb->csum, csum, odd);
288 if (icmp_pointers[icmp_param->data.icmph.type].error)
289 nf_ct_attach(skb, icmp_param->skb);
293 static void icmp_push_reply(struct icmp_bxm *icmp_param,
294 struct ipcm_cookie *ipc, struct rtable **rt)
299 sk = icmp_sk(dev_net((*rt)->dst.dev));
300 if (ip_append_data(sk, icmp_glue_bits, icmp_param,
301 icmp_param->data_len+icmp_param->head_len,
302 icmp_param->head_len,
303 ipc, rt, MSG_DONTWAIT) < 0) {
304 ICMP_INC_STATS_BH(sock_net(sk), ICMP_MIB_OUTERRORS);
305 ip_flush_pending_frames(sk);
306 } else if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) {
307 struct icmphdr *icmph = icmp_hdr(skb);
309 struct sk_buff *skb1;
311 skb_queue_walk(&sk->sk_write_queue, skb1) {
312 csum = csum_add(csum, skb1->csum);
314 csum = csum_partial_copy_nocheck((void *)&icmp_param->data,
316 icmp_param->head_len, csum);
317 icmph->checksum = csum_fold(csum);
318 skb->ip_summed = CHECKSUM_NONE;
319 ip_push_pending_frames(sk);
324 * Driving logic for building and sending ICMP messages.
327 static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
329 struct ipcm_cookie ipc;
330 struct rtable *rt = skb_rtable(skb);
331 struct net *net = dev_net(rt->dst.dev);
333 struct inet_sock *inet;
336 if (ip_options_echo(&icmp_param->replyopts, skb))
339 sk = icmp_xmit_lock(net);
344 icmp_param->data.icmph.checksum = 0;
346 inet->tos = ip_hdr(skb)->tos;
347 daddr = ipc.addr = rt->rt_src;
350 if (icmp_param->replyopts.optlen) {
351 ipc.opt = &icmp_param->replyopts;
353 daddr = icmp_param->replyopts.faddr;
358 .fl4_src = rt->rt_spec_dst,
359 .fl4_tos = RT_TOS(ip_hdr(skb)->tos),
360 .flowi_proto = IPPROTO_ICMP,
362 security_skb_classify_flow(skb, &fl);
363 rt = ip_route_output_key(net, &fl);
367 if (icmpv4_xrlim_allow(net, rt, icmp_param->data.icmph.type,
368 icmp_param->data.icmph.code))
369 icmp_push_reply(icmp_param, &ipc, &rt);
372 icmp_xmit_unlock(sk);
375 static struct rtable *icmp_route_lookup(struct net *net, struct sk_buff *skb_in,
377 __be32 saddr, u8 tos,
379 struct icmp_bxm *param)
382 .fl4_dst = (param->replyopts.srr ?
383 param->replyopts.faddr : iph->saddr),
385 .fl4_tos = RT_TOS(tos),
386 .flowi_proto = IPPROTO_ICMP,
387 .fl4_icmp_type = type,
388 .fl4_icmp_code = code,
390 struct rtable *rt, *rt2;
393 security_skb_classify_flow(skb_in, &fl);
394 rt = __ip_route_output_key(net, &fl);
398 /* No need to clone since we're just using its address. */
402 fl.fl4_src = rt->rt_src;
404 rt = (struct rtable *) xfrm_lookup(net, &rt->dst, &fl, NULL, 0);
408 } else if (PTR_ERR(rt) == -EPERM) {
413 err = xfrm_decode_session_reverse(skb_in, &fl, AF_INET);
415 goto relookup_failed;
417 if (inet_addr_type(net, fl.fl4_src) == RTN_LOCAL) {
418 rt2 = __ip_route_output_key(net, &fl);
422 struct flowi fl2 = {};
423 unsigned long orefdst;
425 fl2.fl4_dst = fl.fl4_src;
426 rt2 = ip_route_output_key(net, &fl2);
429 goto relookup_failed;
432 orefdst = skb_in->_skb_refdst; /* save old refdst */
433 err = ip_route_input(skb_in, fl.fl4_dst, fl.fl4_src,
434 RT_TOS(tos), rt2->dst.dev);
436 dst_release(&rt2->dst);
437 rt2 = skb_rtable(skb_in);
438 skb_in->_skb_refdst = orefdst; /* restore old refdst */
442 goto relookup_failed;
444 rt2 = (struct rtable *) xfrm_lookup(net, &rt2->dst, &fl, NULL, XFRM_LOOKUP_ICMP);
446 dst_release(&rt->dst);
448 } else if (PTR_ERR(rt2) == -EPERM) {
450 dst_release(&rt->dst);
454 goto relookup_failed;
465 * Send an ICMP message in response to a situation
467 * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header.
468 * MAY send more (we do).
469 * MUST NOT change this header information.
470 * MUST NOT reply to a multicast/broadcast IP address.
471 * MUST NOT reply to a multicast/broadcast MAC address.
472 * MUST reply to only the first fragment.
475 void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
479 struct icmp_bxm icmp_param;
480 struct rtable *rt = skb_rtable(skb_in);
481 struct ipcm_cookie ipc;
489 net = dev_net(rt->dst.dev);
492 * Find the original header. It is expected to be valid, of course.
493 * Check this, icmp_send is called from the most obscure devices
496 iph = ip_hdr(skb_in);
498 if ((u8 *)iph < skb_in->head ||
499 (skb_in->network_header + sizeof(*iph)) > skb_in->tail)
503 * No replies to physical multicast/broadcast
505 if (skb_in->pkt_type != PACKET_HOST)
509 * Now check at the protocol level
511 if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
515 * Only reply to fragment 0. We byte re-order the constant
516 * mask for efficiency.
518 if (iph->frag_off & htons(IP_OFFSET))
522 * If we send an ICMP error to an ICMP error a mess would result..
524 if (icmp_pointers[type].error) {
526 * We are an error, check if we are replying to an
529 if (iph->protocol == IPPROTO_ICMP) {
530 u8 _inner_type, *itp;
532 itp = skb_header_pointer(skb_in,
533 skb_network_header(skb_in) +
535 offsetof(struct icmphdr,
544 * Assume any unknown ICMP type is an error. This
545 * isn't specified by the RFC, but think about it..
547 if (*itp > NR_ICMP_TYPES ||
548 icmp_pointers[*itp].error)
553 sk = icmp_xmit_lock(net);
558 * Construct source address and options.
562 if (!(rt->rt_flags & RTCF_LOCAL)) {
563 struct net_device *dev = NULL;
566 if (rt_is_input_route(rt) &&
567 net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr)
568 dev = dev_get_by_index_rcu(net, rt->rt_iif);
571 saddr = inet_select_addr(dev, 0, RT_SCOPE_LINK);
577 tos = icmp_pointers[type].error ? ((iph->tos & IPTOS_TOS_MASK) |
578 IPTOS_PREC_INTERNETCONTROL) :
581 if (ip_options_echo(&icmp_param.replyopts, skb_in))
586 * Prepare data for ICMP header.
589 icmp_param.data.icmph.type = type;
590 icmp_param.data.icmph.code = code;
591 icmp_param.data.icmph.un.gateway = info;
592 icmp_param.data.icmph.checksum = 0;
593 icmp_param.skb = skb_in;
594 icmp_param.offset = skb_network_offset(skb_in);
595 inet_sk(sk)->tos = tos;
596 ipc.addr = iph->saddr;
597 ipc.opt = &icmp_param.replyopts;
600 rt = icmp_route_lookup(net, skb_in, iph, saddr, tos,
601 type, code, &icmp_param);
605 if (!icmpv4_xrlim_allow(net, rt, type, code))
608 /* RFC says return as much as we can without exceeding 576 bytes. */
610 room = dst_mtu(&rt->dst);
613 room -= sizeof(struct iphdr) + icmp_param.replyopts.optlen;
614 room -= sizeof(struct icmphdr);
616 icmp_param.data_len = skb_in->len - icmp_param.offset;
617 if (icmp_param.data_len > room)
618 icmp_param.data_len = room;
619 icmp_param.head_len = sizeof(struct icmphdr);
621 icmp_push_reply(&icmp_param, &ipc, &rt);
625 icmp_xmit_unlock(sk);
628 EXPORT_SYMBOL(icmp_send);
632 * Handle ICMP_DEST_UNREACH, ICMP_TIME_EXCEED, and ICMP_QUENCH.
635 static void icmp_unreach(struct sk_buff *skb)
638 struct icmphdr *icmph;
640 const struct net_protocol *ipprot;
644 net = dev_net(skb_dst(skb)->dev);
647 * Incomplete header ?
648 * Only checks for the IP header, there should be an
649 * additional check for longer headers in upper levels.
652 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
655 icmph = icmp_hdr(skb);
656 iph = (struct iphdr *)skb->data;
658 if (iph->ihl < 5) /* Mangled header, drop. */
661 if (icmph->type == ICMP_DEST_UNREACH) {
662 switch (icmph->code & 15) {
663 case ICMP_NET_UNREACH:
664 case ICMP_HOST_UNREACH:
665 case ICMP_PROT_UNREACH:
666 case ICMP_PORT_UNREACH:
668 case ICMP_FRAG_NEEDED:
669 if (ipv4_config.no_pmtu_disc) {
670 LIMIT_NETDEBUG(KERN_INFO "ICMP: %pI4: fragmentation needed and DF set.\n",
673 info = ip_rt_frag_needed(net, iph,
674 ntohs(icmph->un.frag.mtu),
681 LIMIT_NETDEBUG(KERN_INFO "ICMP: %pI4: Source Route Failed.\n",
687 if (icmph->code > NR_ICMP_UNREACH)
689 } else if (icmph->type == ICMP_PARAMETERPROB)
690 info = ntohl(icmph->un.gateway) >> 24;
693 * Throw it at our lower layers
695 * RFC 1122: 3.2.2 MUST extract the protocol ID from the passed
697 * RFC 1122: 3.2.2.1 MUST pass ICMP unreach messages to the
699 * RFC 1122: 3.2.2.2 MUST pass ICMP time expired messages to
704 * Check the other end isnt violating RFC 1122. Some routers send
705 * bogus responses to broadcast frames. If you see this message
706 * first check your netmask matches at both ends, if it does then
707 * get the other vendor to fix their kit.
710 if (!net->ipv4.sysctl_icmp_ignore_bogus_error_responses &&
711 inet_addr_type(net, iph->daddr) == RTN_BROADCAST) {
713 printk(KERN_WARNING "%pI4 sent an invalid ICMP "
715 "error to a broadcast: %pI4 on %s\n",
717 icmph->type, icmph->code,
723 /* Checkin full IP header plus 8 bytes of protocol to
724 * avoid additional coding at protocol handlers.
726 if (!pskb_may_pull(skb, iph->ihl * 4 + 8))
729 iph = (struct iphdr *)skb->data;
730 protocol = iph->protocol;
733 * Deliver ICMP message to raw sockets. Pretty useless feature?
735 raw_icmp_error(skb, protocol, info);
737 hash = protocol & (MAX_INET_PROTOS - 1);
739 ipprot = rcu_dereference(inet_protos[hash]);
740 if (ipprot && ipprot->err_handler)
741 ipprot->err_handler(skb, info);
747 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
753 * Handle ICMP_REDIRECT.
756 static void icmp_redirect(struct sk_buff *skb)
760 if (skb->len < sizeof(struct iphdr))
764 * Get the copied header of the packet that caused the redirect
766 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
769 iph = (struct iphdr *)skb->data;
771 switch (icmp_hdr(skb)->code & 7) {
773 case ICMP_REDIR_NETTOS:
775 * As per RFC recommendations now handle it as a host redirect.
777 case ICMP_REDIR_HOST:
778 case ICMP_REDIR_HOSTTOS:
779 ip_rt_redirect(ip_hdr(skb)->saddr, iph->daddr,
780 icmp_hdr(skb)->un.gateway,
781 iph->saddr, skb->dev);
787 ICMP_INC_STATS_BH(dev_net(skb->dev), ICMP_MIB_INERRORS);
792 * Handle ICMP_ECHO ("ping") requests.
794 * RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo
796 * RFC 1122: 3.2.2.6 Data received in the ICMP_ECHO request MUST be
797 * included in the reply.
798 * RFC 1812: 4.3.3.6 SHOULD have a config option for silently ignoring
799 * echo requests, MUST have default=NOT.
800 * See also WRT handling of options once they are done and working.
803 static void icmp_echo(struct sk_buff *skb)
807 net = dev_net(skb_dst(skb)->dev);
808 if (!net->ipv4.sysctl_icmp_echo_ignore_all) {
809 struct icmp_bxm icmp_param;
811 icmp_param.data.icmph = *icmp_hdr(skb);
812 icmp_param.data.icmph.type = ICMP_ECHOREPLY;
813 icmp_param.skb = skb;
814 icmp_param.offset = 0;
815 icmp_param.data_len = skb->len;
816 icmp_param.head_len = sizeof(struct icmphdr);
817 icmp_reply(&icmp_param, skb);
822 * Handle ICMP Timestamp requests.
823 * RFC 1122: 3.2.2.8 MAY implement ICMP timestamp requests.
824 * SHOULD be in the kernel for minimum random latency.
825 * MUST be accurate to a few minutes.
826 * MUST be updated at least at 15Hz.
828 static void icmp_timestamp(struct sk_buff *skb)
831 struct icmp_bxm icmp_param;
839 * Fill in the current time as ms since midnight UT:
842 icmp_param.data.times[1] = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC +
843 tv.tv_nsec / NSEC_PER_MSEC);
844 icmp_param.data.times[2] = icmp_param.data.times[1];
845 if (skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4))
847 icmp_param.data.icmph = *icmp_hdr(skb);
848 icmp_param.data.icmph.type = ICMP_TIMESTAMPREPLY;
849 icmp_param.data.icmph.code = 0;
850 icmp_param.skb = skb;
851 icmp_param.offset = 0;
852 icmp_param.data_len = 0;
853 icmp_param.head_len = sizeof(struct icmphdr) + 12;
854 icmp_reply(&icmp_param, skb);
858 ICMP_INC_STATS_BH(dev_net(skb_dst(skb)->dev), ICMP_MIB_INERRORS);
864 * Handle ICMP_ADDRESS_MASK requests. (RFC950)
866 * RFC1122 (3.2.2.9). A host MUST only send replies to
867 * ADDRESS_MASK requests if it's been configured as an address mask
868 * agent. Receiving a request doesn't constitute implicit permission to
869 * act as one. Of course, implementing this correctly requires (SHOULD)
870 * a way to turn the functionality on and off. Another one for sysctl(),
873 * RFC1812 (4.3.3.9). A router MUST implement it.
874 * A router SHOULD have switch turning it on/off.
875 * This switch MUST be ON by default.
877 * Gratuitous replies, zero-source replies are not implemented,
878 * that complies with RFC. DO NOT implement them!!! All the idea
879 * of broadcast addrmask replies as specified in RFC950 is broken.
880 * The problem is that it is not uncommon to have several prefixes
881 * on one physical interface. Moreover, addrmask agent can even be
882 * not aware of existing another prefixes.
883 * If source is zero, addrmask agent cannot choose correct prefix.
884 * Gratuitous mask announcements suffer from the same problem.
885 * RFC1812 explains it, but still allows to use ADDRMASK,
886 * that is pretty silly. --ANK
888 * All these rules are so bizarre, that I removed kernel addrmask
889 * support at all. It is wrong, it is obsolete, nobody uses it in
892 * Furthermore you can do it with a usermode address agent program
896 static void icmp_address(struct sk_buff *skb)
900 printk(KERN_DEBUG "a guy asks for address mask. Who is it?\n");
905 * RFC1812 (4.3.3.9). A router SHOULD listen all replies, and complain
906 * loudly if an inconsistency is found.
907 * called with rcu_read_lock()
910 static void icmp_address_reply(struct sk_buff *skb)
912 struct rtable *rt = skb_rtable(skb);
913 struct net_device *dev = skb->dev;
914 struct in_device *in_dev;
915 struct in_ifaddr *ifa;
917 if (skb->len < 4 || !(rt->rt_flags&RTCF_DIRECTSRC))
920 in_dev = __in_dev_get_rcu(dev);
924 if (in_dev->ifa_list &&
925 IN_DEV_LOG_MARTIANS(in_dev) &&
926 IN_DEV_FORWARD(in_dev)) {
929 mp = skb_header_pointer(skb, 0, sizeof(_mask), &_mask);
931 for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) {
932 if (*mp == ifa->ifa_mask &&
933 inet_ifa_match(rt->rt_src, ifa))
936 if (!ifa && net_ratelimit()) {
937 printk(KERN_INFO "Wrong address mask %pI4 from %s/%pI4\n",
938 mp, dev->name, &rt->rt_src);
943 static void icmp_discard(struct sk_buff *skb)
948 * Deal with incoming ICMP packets.
950 int icmp_rcv(struct sk_buff *skb)
952 struct icmphdr *icmph;
953 struct rtable *rt = skb_rtable(skb);
954 struct net *net = dev_net(rt->dst.dev);
956 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
957 struct sec_path *sp = skb_sec_path(skb);
960 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
964 if (!pskb_may_pull(skb, sizeof(*icmph) + sizeof(struct iphdr)))
967 nh = skb_network_offset(skb);
968 skb_set_network_header(skb, sizeof(*icmph));
970 if (!xfrm4_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
973 skb_set_network_header(skb, nh);
976 ICMP_INC_STATS_BH(net, ICMP_MIB_INMSGS);
978 switch (skb->ip_summed) {
979 case CHECKSUM_COMPLETE:
980 if (!csum_fold(skb->csum))
985 if (__skb_checksum_complete(skb))
989 if (!pskb_pull(skb, sizeof(*icmph)))
992 icmph = icmp_hdr(skb);
994 ICMPMSGIN_INC_STATS_BH(net, icmph->type);
996 * 18 is the highest 'known' ICMP type. Anything else is a mystery
998 * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
1001 if (icmph->type > NR_ICMP_TYPES)
1006 * Parse the ICMP message
1009 if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
1011 * RFC 1122: 3.2.2.6 An ICMP_ECHO to broadcast MAY be
1012 * silently ignored (we let user decide with a sysctl).
1013 * RFC 1122: 3.2.2.8 An ICMP_TIMESTAMP MAY be silently
1014 * discarded if to broadcast/multicast.
1016 if ((icmph->type == ICMP_ECHO ||
1017 icmph->type == ICMP_TIMESTAMP) &&
1018 net->ipv4.sysctl_icmp_echo_ignore_broadcasts) {
1021 if (icmph->type != ICMP_ECHO &&
1022 icmph->type != ICMP_TIMESTAMP &&
1023 icmph->type != ICMP_ADDRESS &&
1024 icmph->type != ICMP_ADDRESSREPLY) {
1029 icmp_pointers[icmph->type].handler(skb);
1035 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
1040 * This table is the definition of how we handle ICMP.
1042 static const struct icmp_control icmp_pointers[NR_ICMP_TYPES + 1] = {
1043 [ICMP_ECHOREPLY] = {
1044 .handler = icmp_discard,
1047 .handler = icmp_discard,
1051 .handler = icmp_discard,
1054 [ICMP_DEST_UNREACH] = {
1055 .handler = icmp_unreach,
1058 [ICMP_SOURCE_QUENCH] = {
1059 .handler = icmp_unreach,
1063 .handler = icmp_redirect,
1067 .handler = icmp_discard,
1071 .handler = icmp_discard,
1075 .handler = icmp_echo,
1078 .handler = icmp_discard,
1082 .handler = icmp_discard,
1085 [ICMP_TIME_EXCEEDED] = {
1086 .handler = icmp_unreach,
1089 [ICMP_PARAMETERPROB] = {
1090 .handler = icmp_unreach,
1093 [ICMP_TIMESTAMP] = {
1094 .handler = icmp_timestamp,
1096 [ICMP_TIMESTAMPREPLY] = {
1097 .handler = icmp_discard,
1099 [ICMP_INFO_REQUEST] = {
1100 .handler = icmp_discard,
1102 [ICMP_INFO_REPLY] = {
1103 .handler = icmp_discard,
1106 .handler = icmp_address,
1108 [ICMP_ADDRESSREPLY] = {
1109 .handler = icmp_address_reply,
1113 static void __net_exit icmp_sk_exit(struct net *net)
1117 for_each_possible_cpu(i)
1118 inet_ctl_sock_destroy(net->ipv4.icmp_sk[i]);
1119 kfree(net->ipv4.icmp_sk);
1120 net->ipv4.icmp_sk = NULL;
1123 static int __net_init icmp_sk_init(struct net *net)
1128 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL);
1129 if (net->ipv4.icmp_sk == NULL)
1132 for_each_possible_cpu(i) {
1135 err = inet_ctl_sock_create(&sk, PF_INET,
1136 SOCK_RAW, IPPROTO_ICMP, net);
1140 net->ipv4.icmp_sk[i] = sk;
1142 /* Enough space for 2 64K ICMP packets, including
1143 * sk_buff struct overhead.
1146 (2 * ((64 * 1024) + sizeof(struct sk_buff)));
1149 * Speedup sock_wfree()
1151 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
1152 inet_sk(sk)->pmtudisc = IP_PMTUDISC_DONT;
1155 /* Control parameters for ECHO replies. */
1156 net->ipv4.sysctl_icmp_echo_ignore_all = 0;
1157 net->ipv4.sysctl_icmp_echo_ignore_broadcasts = 1;
1159 /* Control parameter - ignore bogus broadcast responses? */
1160 net->ipv4.sysctl_icmp_ignore_bogus_error_responses = 1;
1163 * Configurable global rate limit.
1165 * ratelimit defines tokens/packet consumed for dst->rate_token
1166 * bucket ratemask defines which icmp types are ratelimited by
1167 * setting it's bit position.
1170 * dest unreachable (3), source quench (4),
1171 * time exceeded (11), parameter problem (12)
1174 net->ipv4.sysctl_icmp_ratelimit = 1 * HZ;
1175 net->ipv4.sysctl_icmp_ratemask = 0x1818;
1176 net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr = 0;
1181 for_each_possible_cpu(i)
1182 inet_ctl_sock_destroy(net->ipv4.icmp_sk[i]);
1183 kfree(net->ipv4.icmp_sk);
1187 static struct pernet_operations __net_initdata icmp_sk_ops = {
1188 .init = icmp_sk_init,
1189 .exit = icmp_sk_exit,
1192 int __init icmp_init(void)
1194 return register_pernet_subsys(&icmp_sk_ops);