2 * NET3: Implementation of the ICMP protocol layer.
4 * Alan Cox, <alan@redhat.com>
6 * Version: $Id: icmp.c,v 1.85 2002/02/01 22:01:03 davem Exp $
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
13 * Some of the function names and the icmp unreach table for this
14 * module were derived from [icmp.c 1.0.11 06/02/93] by
15 * Ross Biro, Fred N. van Kempen, Mark Evans, Alan Cox, Gerhard Koerting.
16 * Other than that this module is a complete rewrite.
19 * Clemens Fruhwirth : introduce global icmp rate limiting
20 * with icmp type masking ability instead
21 * of broken per type icmp timeouts.
22 * Mike Shaver : RFC1122 checks.
23 * Alan Cox : Multicast ping reply as self.
24 * Alan Cox : Fix atomicity lockup in ip_build_xmit
26 * Alan Cox : Added 216,128 byte paths to the MTU
28 * Martin Mares : RFC1812 checks.
29 * Martin Mares : Can be configured to follow redirects
30 * if acting as a router _without_ a
31 * routing protocol (RFC 1812).
32 * Martin Mares : Echo requests may be configured to
33 * be ignored (RFC 1812).
34 * Martin Mares : Limitation of ICMP error message
35 * transmit rate (RFC 1812).
36 * Martin Mares : TOS and Precedence set correctly
38 * Martin Mares : Now copying as much data from the
39 * original packet as we can without
40 * exceeding 576 bytes (RFC 1812).
41 * Willy Konynenberg : Transparent proxying support.
42 * Keith Owens : RFC1191 correction for 4.2BSD based
44 * Thomas Quinot : ICMP Dest Unreach codes up to 15 are
46 * Andi Kleen : Check all packet lengths properly
47 * and moved all kfree_skb() up to
49 * Andi Kleen : Move the rate limit bookkeeping
50 * into the dest entry and use a token
51 * bucket filter (thanks to ANK). Make
52 * the rates sysctl configurable.
53 * Yu Tianli : Fixed two ugly bugs in icmp_send
54 * - IP option length was accounted wrongly
55 * - ICMP header length was not accounted
57 * Tristan Greaves : Added sysctl option to ignore bogus
58 * broadcast responses from broken routers.
62 * - Should use skb_pull() instead of all the manual checking.
63 * This would also greatly simply some upper layer error handlers. --AK
67 #include <linux/config.h>
68 #include <linux/module.h>
69 #include <linux/types.h>
70 #include <linux/jiffies.h>
71 #include <linux/kernel.h>
72 #include <linux/fcntl.h>
73 #include <linux/socket.h>
75 #include <linux/inet.h>
76 #include <linux/netdevice.h>
77 #include <linux/string.h>
78 #include <linux/netfilter_ipv4.h>
81 #include <net/route.h>
82 #include <net/protocol.h>
87 #include <linux/skbuff.h>
89 #include <linux/errno.h>
90 #include <linux/timer.h>
91 #include <linux/init.h>
92 #include <asm/system.h>
93 #include <asm/uaccess.h>
94 #include <net/checksum.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 icmp_mib, icmp_statistics);
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 */
189 /* Control parameters for ECHO replies. */
190 int sysctl_icmp_echo_ignore_all;
191 int sysctl_icmp_echo_ignore_broadcasts;
193 /* Control parameter - ignore bogus broadcast responses? */
194 int sysctl_icmp_ignore_bogus_error_responses;
197 * Configurable global rate limit.
199 * ratelimit defines tokens/packet consumed for dst->rate_token bucket
200 * ratemask defines which icmp types are ratelimited by setting
204 * dest unreachable (3), source quench (4),
205 * time exceeded (11), parameter problem (12)
208 int sysctl_icmp_ratelimit = 1 * HZ;
209 int sysctl_icmp_ratemask = 0x1818;
212 * ICMP control array. This specifies what to do with each ICMP.
215 struct icmp_control {
216 int output_off; /* Field offset for increment on output */
217 int input_off; /* Field offset for increment on input */
218 void (*handler)(struct sk_buff *skb);
219 short error; /* This ICMP is classed as an error message */
222 static struct icmp_control icmp_pointers[NR_ICMP_TYPES+1];
225 * The ICMP socket(s). This is the most convenient way to flow control
226 * our ICMP output as well as maintain a clean interface throughout
227 * all layers. All Socketless IP sends will soon be gone.
229 * On SMP we have one ICMP socket per-cpu.
231 static DEFINE_PER_CPU(struct socket *, __icmp_socket) = NULL;
232 #define icmp_socket __get_cpu_var(__icmp_socket)
234 static __inline__ int icmp_xmit_lock(void)
238 if (unlikely(!spin_trylock(&icmp_socket->sk->sk_lock.slock))) {
239 /* This can happen if the output path signals a
240 * dst_link_failure() for an outgoing ICMP packet.
248 static void icmp_xmit_unlock(void)
250 spin_unlock_bh(&icmp_socket->sk->sk_lock.slock);
254 * Send an ICMP frame.
258 * Check transmit rate limitation for given message.
259 * The rate information is held in the destination cache now.
260 * This function is generic and could be used for other purposes
261 * too. It uses a Token bucket filter as suggested by Alexey Kuznetsov.
263 * Note that the same dst_entry fields are modified by functions in
264 * route.c too, but these work for packet destinations while xrlim_allow
265 * works for icmp destinations. This means the rate limiting information
266 * for one "ip object" is shared - and these ICMPs are twice limited:
267 * by source and by destination.
269 * RFC 1812: 4.3.2.8 SHOULD be able to limit error message rate
270 * SHOULD allow setting of rate limits
272 * Shared between ICMPv4 and ICMPv6.
274 #define XRLIM_BURST_FACTOR 6
275 int xrlim_allow(struct dst_entry *dst, int timeout)
281 dst->rate_tokens += now - dst->rate_last;
282 dst->rate_last = now;
283 if (dst->rate_tokens > XRLIM_BURST_FACTOR * timeout)
284 dst->rate_tokens = XRLIM_BURST_FACTOR * timeout;
285 if (dst->rate_tokens >= timeout) {
286 dst->rate_tokens -= timeout;
292 static inline int icmpv4_xrlim_allow(struct rtable *rt, int type, int code)
294 struct dst_entry *dst = &rt->u.dst;
297 if (type > NR_ICMP_TYPES)
300 /* Don't limit PMTU discovery. */
301 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
304 /* No rate limit on loopback */
305 if (dst->dev && (dst->dev->flags&IFF_LOOPBACK))
308 /* Limit if icmp type is enabled in ratemask. */
309 if ((1 << type) & sysctl_icmp_ratemask)
310 rc = xrlim_allow(dst, sysctl_icmp_ratelimit);
316 * Maintain the counters used in the SNMP statistics for outgoing ICMP
318 static void icmp_out_count(int type)
320 if (type <= NR_ICMP_TYPES) {
321 ICMP_INC_STATS_FIELD(icmp_pointers[type].output_off);
322 ICMP_INC_STATS(IcmpOutMsgs);
327 * Checksum each fragment, and on the first include the headers and final
330 int icmp_glue_bits(void *from, char *to, int offset, int len, int odd,
333 struct icmp_bxm *icmp_param = (struct icmp_bxm *)from;
336 csum = skb_copy_and_csum_bits(icmp_param->skb,
337 icmp_param->offset + offset,
340 skb->csum = csum_block_add(skb->csum, csum, odd);
344 static void icmp_push_reply(struct icmp_bxm *icmp_param,
345 struct ipcm_cookie *ipc, struct rtable *rt)
349 ip_append_data(icmp_socket->sk, icmp_glue_bits, icmp_param,
350 icmp_param->data_len+icmp_param->head_len,
351 icmp_param->head_len,
352 ipc, rt, MSG_DONTWAIT);
354 if ((skb = skb_peek(&icmp_socket->sk->sk_write_queue)) != NULL) {
355 struct icmphdr *icmph = skb->h.icmph;
356 unsigned int csum = 0;
357 struct sk_buff *skb1;
359 skb_queue_walk(&icmp_socket->sk->sk_write_queue, skb1) {
360 csum = csum_add(csum, skb1->csum);
362 csum = csum_partial_copy_nocheck((void *)&icmp_param->data,
364 icmp_param->head_len, csum);
365 icmph->checksum = csum_fold(csum);
366 skb->ip_summed = CHECKSUM_NONE;
367 ip_push_pending_frames(icmp_socket->sk);
372 * Driving logic for building and sending ICMP messages.
375 static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
377 struct sock *sk = icmp_socket->sk;
378 struct inet_opt *inet = inet_sk(sk);
379 struct ipcm_cookie ipc;
380 struct rtable *rt = (struct rtable *)skb->dst;
383 if (ip_options_echo(&icmp_param->replyopts, skb))
386 if (icmp_xmit_lock())
389 icmp_param->data.icmph.checksum = 0;
390 icmp_out_count(icmp_param->data.icmph.type);
392 inet->tos = skb->nh.iph->tos;
393 daddr = ipc.addr = rt->rt_src;
395 if (icmp_param->replyopts.optlen) {
396 ipc.opt = &icmp_param->replyopts;
398 daddr = icmp_param->replyopts.faddr;
401 struct flowi fl = { .nl_u = { .ip4_u =
403 .saddr = rt->rt_spec_dst,
404 .tos = RT_TOS(skb->nh.iph->tos) } },
405 .proto = IPPROTO_ICMP };
406 if (ip_route_output_key(&rt, &fl))
409 if (icmpv4_xrlim_allow(rt, icmp_param->data.icmph.type,
410 icmp_param->data.icmph.code))
411 icmp_push_reply(icmp_param, &ipc, rt);
420 * Send an ICMP message in response to a situation
422 * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header.
423 * MAY send more (we do).
424 * MUST NOT change this header information.
425 * MUST NOT reply to a multicast/broadcast IP address.
426 * MUST NOT reply to a multicast/broadcast MAC address.
427 * MUST reply to only the first fragment.
430 void icmp_send(struct sk_buff *skb_in, int type, int code, u32 info)
434 struct icmp_bxm icmp_param;
435 struct rtable *rt = (struct rtable *)skb_in->dst;
436 struct ipcm_cookie ipc;
444 * Find the original header. It is expected to be valid, of course.
445 * Check this, icmp_send is called from the most obscure devices
448 iph = skb_in->nh.iph;
450 if ((u8 *)iph < skb_in->head || (u8 *)(iph + 1) > skb_in->tail)
454 * No replies to physical multicast/broadcast
456 if (skb_in->pkt_type != PACKET_HOST)
460 * Now check at the protocol level
462 if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
466 * Only reply to fragment 0. We byte re-order the constant
467 * mask for efficiency.
469 if (iph->frag_off & htons(IP_OFFSET))
473 * If we send an ICMP error to an ICMP error a mess would result..
475 if (icmp_pointers[type].error) {
477 * We are an error, check if we are replying to an
480 if (iph->protocol == IPPROTO_ICMP) {
483 if (skb_copy_bits(skb_in,
484 skb_in->nh.raw + (iph->ihl << 2) +
485 offsetof(struct icmphdr, type) -
486 skb_in->data, &inner_type, 1))
490 * Assume any unknown ICMP type is an error. This
491 * isn't specified by the RFC, but think about it..
493 if (inner_type > NR_ICMP_TYPES ||
494 icmp_pointers[inner_type].error)
499 if (icmp_xmit_lock())
503 * Construct source address and options.
506 #ifdef CONFIG_IP_ROUTE_NAT
508 * Restore original addresses if packet has been translated.
510 if (rt->rt_flags & RTCF_NAT && IPCB(skb_in)->flags & IPSKB_TRANSLATED) {
511 iph->daddr = rt->fl.fl4_dst;
512 iph->saddr = rt->fl.fl4_src;
517 if (!(rt->rt_flags & RTCF_LOCAL))
520 tos = icmp_pointers[type].error ? ((iph->tos & IPTOS_TOS_MASK) |
521 IPTOS_PREC_INTERNETCONTROL) :
525 struct flowi fl = { .nl_u = { .ip4_u = { .daddr = iph->saddr,
527 .tos = RT_TOS(tos) } },
528 .proto = IPPROTO_ICMP };
529 if (ip_route_output_key(&rt, &fl))
532 if (ip_options_echo(&icmp_param.replyopts, skb_in))
537 * Prepare data for ICMP header.
540 icmp_param.data.icmph.type = type;
541 icmp_param.data.icmph.code = code;
542 icmp_param.data.icmph.un.gateway = info;
543 icmp_param.data.icmph.checksum = 0;
544 icmp_param.skb = skb_in;
545 icmp_param.offset = skb_in->nh.raw - skb_in->data;
546 icmp_out_count(icmp_param.data.icmph.type);
547 inet_sk(icmp_socket->sk)->tos = tos;
548 ipc.addr = iph->saddr;
549 ipc.opt = &icmp_param.replyopts;
550 if (icmp_param.replyopts.srr) {
551 struct flowi fl = { .nl_u = { .ip4_u =
552 { .daddr = icmp_param.replyopts.faddr,
554 .tos = RT_TOS(tos) } },
555 .proto = IPPROTO_ICMP };
557 if (ip_route_output_key(&rt, &fl))
561 if (!icmpv4_xrlim_allow(rt, type, code))
564 /* RFC says return as much as we can without exceeding 576 bytes. */
566 room = dst_pmtu(&rt->u.dst);
569 room -= sizeof(struct iphdr) + icmp_param.replyopts.optlen;
570 room -= sizeof(struct icmphdr);
572 icmp_param.data_len = skb_in->len - icmp_param.offset;
573 if (icmp_param.data_len > room)
574 icmp_param.data_len = room;
575 icmp_param.head_len = sizeof(struct icmphdr);
577 icmp_push_reply(&icmp_param, &ipc, rt);
587 * Handle ICMP_DEST_UNREACH, ICMP_TIME_EXCEED, and ICMP_QUENCH.
590 static void icmp_unreach(struct sk_buff *skb)
593 struct icmphdr *icmph;
595 struct inet_protocol *ipprot;
600 * Incomplete header ?
601 * Only checks for the IP header, there should be an
602 * additional check for longer headers in upper levels.
605 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
608 icmph = skb->h.icmph;
609 iph = (struct iphdr *)skb->data;
611 if (iph->ihl < 5) /* Mangled header, drop. */
614 if (icmph->type == ICMP_DEST_UNREACH) {
615 switch (icmph->code & 15) {
616 case ICMP_NET_UNREACH:
617 case ICMP_HOST_UNREACH:
618 case ICMP_PROT_UNREACH:
619 case ICMP_PORT_UNREACH:
621 case ICMP_FRAG_NEEDED:
622 if (ipv4_config.no_pmtu_disc) {
624 printk(KERN_INFO "ICMP: %u.%u.%u.%u: "
625 "fragmentation needed "
627 NIPQUAD(iph->daddr)));
629 info = ip_rt_frag_needed(iph,
630 ntohs(icmph->un.frag.mtu));
637 printk(KERN_INFO "ICMP: %u.%u.%u.%u: Source "
639 NIPQUAD(iph->daddr)));
644 if (icmph->code > NR_ICMP_UNREACH)
646 } else if (icmph->type == ICMP_PARAMETERPROB)
647 info = ntohl(icmph->un.gateway) >> 24;
650 * Throw it at our lower layers
652 * RFC 1122: 3.2.2 MUST extract the protocol ID from the passed
654 * RFC 1122: 3.2.2.1 MUST pass ICMP unreach messages to the
656 * RFC 1122: 3.2.2.2 MUST pass ICMP time expired messages to
661 * Check the other end isnt violating RFC 1122. Some routers send
662 * bogus responses to broadcast frames. If you see this message
663 * first check your netmask matches at both ends, if it does then
664 * get the other vendor to fix their kit.
667 if (!sysctl_icmp_ignore_bogus_error_responses &&
668 inet_addr_type(iph->daddr) == RTN_BROADCAST) {
670 printk(KERN_WARNING "%u.%u.%u.%u sent an invalid ICMP "
672 "error to a broadcast: %u.%u.%u.%u on %s\n",
673 NIPQUAD(skb->nh.iph->saddr),
674 icmph->type, icmph->code,
680 /* Checkin full IP header plus 8 bytes of protocol to
681 * avoid additional coding at protocol handlers.
683 if (!pskb_may_pull(skb, iph->ihl * 4 + 8))
686 iph = (struct iphdr *)skb->data;
687 protocol = iph->protocol;
690 * Deliver ICMP message to raw sockets. Pretty useless feature?
693 /* Note: See raw.c and net/raw.h, RAWV4_HTABLE_SIZE==MAX_INET_PROTOS */
694 hash = protocol & (MAX_INET_PROTOS - 1);
695 read_lock(&raw_v4_lock);
696 if ((raw_sk = sk_head(&raw_v4_htable[hash])) != NULL) {
697 while ((raw_sk = __raw_v4_lookup(raw_sk, protocol, iph->daddr,
699 skb->dev->ifindex)) != NULL) {
700 raw_err(raw_sk, skb, info);
701 raw_sk = sk_next(raw_sk);
702 iph = (struct iphdr *)skb->data;
705 read_unlock(&raw_v4_lock);
708 ipprot = inet_protos[hash];
709 smp_read_barrier_depends();
710 if (ipprot && ipprot->err_handler)
711 ipprot->err_handler(skb, info);
717 ICMP_INC_STATS_BH(IcmpInErrors);
723 * Handle ICMP_REDIRECT.
726 static void icmp_redirect(struct sk_buff *skb)
731 if (skb->len < sizeof(struct iphdr))
735 * Get the copied header of the packet that caused the redirect
737 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
740 iph = (struct iphdr *)skb->data;
743 switch (skb->h.icmph->code & 7) {
745 case ICMP_REDIR_NETTOS:
747 * As per RFC recommendations now handle it as a host redirect.
749 case ICMP_REDIR_HOST:
750 case ICMP_REDIR_HOSTTOS:
751 ip_rt_redirect(skb->nh.iph->saddr, ip, skb->h.icmph->un.gateway,
752 iph->saddr, iph->tos, skb->dev);
758 ICMP_INC_STATS_BH(IcmpInErrors);
763 * Handle ICMP_ECHO ("ping") requests.
765 * RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo
767 * RFC 1122: 3.2.2.6 Data received in the ICMP_ECHO request MUST be
768 * included in the reply.
769 * RFC 1812: 4.3.3.6 SHOULD have a config option for silently ignoring
770 * echo requests, MUST have default=NOT.
771 * See also WRT handling of options once they are done and working.
774 static void icmp_echo(struct sk_buff *skb)
776 if (!sysctl_icmp_echo_ignore_all) {
777 struct icmp_bxm icmp_param;
779 icmp_param.data.icmph = *skb->h.icmph;
780 icmp_param.data.icmph.type = ICMP_ECHOREPLY;
781 icmp_param.skb = skb;
782 icmp_param.offset = 0;
783 icmp_param.data_len = skb->len;
784 icmp_param.head_len = sizeof(struct icmphdr);
785 icmp_reply(&icmp_param, skb);
790 * Handle ICMP Timestamp requests.
791 * RFC 1122: 3.2.2.8 MAY implement ICMP timestamp requests.
792 * SHOULD be in the kernel for minimum random latency.
793 * MUST be accurate to a few minutes.
794 * MUST be updated at least at 15Hz.
796 static void icmp_timestamp(struct sk_buff *skb)
799 struct icmp_bxm icmp_param;
807 * Fill in the current time as ms since midnight UT:
809 do_gettimeofday(&tv);
810 icmp_param.data.times[1] = htonl((tv.tv_sec % 86400) * 1000 +
812 icmp_param.data.times[2] = icmp_param.data.times[1];
813 if (skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4))
815 icmp_param.data.icmph = *skb->h.icmph;
816 icmp_param.data.icmph.type = ICMP_TIMESTAMPREPLY;
817 icmp_param.data.icmph.code = 0;
818 icmp_param.skb = skb;
819 icmp_param.offset = 0;
820 icmp_param.data_len = 0;
821 icmp_param.head_len = sizeof(struct icmphdr) + 12;
822 icmp_reply(&icmp_param, skb);
826 ICMP_INC_STATS_BH(IcmpInErrors);
832 * Handle ICMP_ADDRESS_MASK requests. (RFC950)
834 * RFC1122 (3.2.2.9). A host MUST only send replies to
835 * ADDRESS_MASK requests if it's been configured as an address mask
836 * agent. Receiving a request doesn't constitute implicit permission to
837 * act as one. Of course, implementing this correctly requires (SHOULD)
838 * a way to turn the functionality on and off. Another one for sysctl(),
841 * RFC1812 (4.3.3.9). A router MUST implement it.
842 * A router SHOULD have switch turning it on/off.
843 * This switch MUST be ON by default.
845 * Gratuitous replies, zero-source replies are not implemented,
846 * that complies with RFC. DO NOT implement them!!! All the idea
847 * of broadcast addrmask replies as specified in RFC950 is broken.
848 * The problem is that it is not uncommon to have several prefixes
849 * on one physical interface. Moreover, addrmask agent can even be
850 * not aware of existing another prefixes.
851 * If source is zero, addrmask agent cannot choose correct prefix.
852 * Gratuitous mask announcements suffer from the same problem.
853 * RFC1812 explains it, but still allows to use ADDRMASK,
854 * that is pretty silly. --ANK
856 * All these rules are so bizarre, that I removed kernel addrmask
857 * support at all. It is wrong, it is obsolete, nobody uses it in
860 * Furthermore you can do it with a usermode address agent program
864 static void icmp_address(struct sk_buff *skb)
868 printk(KERN_DEBUG "a guy asks for address mask. Who is it?\n");
873 * RFC1812 (4.3.3.9). A router SHOULD listen all replies, and complain
874 * loudly if an inconsistency is found.
877 static void icmp_address_reply(struct sk_buff *skb)
879 struct rtable *rt = (struct rtable *)skb->dst;
880 struct net_device *dev = skb->dev;
881 struct in_device *in_dev;
882 struct in_ifaddr *ifa;
885 if (skb->len < 4 || !(rt->rt_flags&RTCF_DIRECTSRC))
888 in_dev = in_dev_get(dev);
891 read_lock(&in_dev->lock);
892 if (in_dev->ifa_list &&
893 IN_DEV_LOG_MARTIANS(in_dev) &&
894 IN_DEV_FORWARD(in_dev)) {
895 if (skb_copy_bits(skb, 0, &mask, 4))
897 for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) {
898 if (mask == ifa->ifa_mask &&
899 inet_ifa_match(rt->rt_src, ifa))
902 if (!ifa && net_ratelimit()) {
903 printk(KERN_INFO "Wrong address mask %u.%u.%u.%u from "
905 NIPQUAD(mask), dev->name, NIPQUAD(rt->rt_src));
908 read_unlock(&in_dev->lock);
913 static void icmp_discard(struct sk_buff *skb)
918 * Deal with incoming ICMP packets.
920 int icmp_rcv(struct sk_buff *skb)
922 struct icmphdr *icmph;
923 struct rtable *rt = (struct rtable *)skb->dst;
925 ICMP_INC_STATS_BH(IcmpInMsgs);
927 switch (skb->ip_summed) {
929 if (!(u16)csum_fold(skb->csum))
931 NETDEBUG(if (net_ratelimit())
932 printk(KERN_DEBUG "icmp v4 hw csum failure\n"));
934 if ((u16)csum_fold(skb_checksum(skb, 0, skb->len, 0)))
939 if (!pskb_pull(skb, sizeof(struct icmphdr)))
942 icmph = skb->h.icmph;
945 * 18 is the highest 'known' ICMP type. Anything else is a mystery
947 * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
950 if (icmph->type > NR_ICMP_TYPES)
955 * Parse the ICMP message
958 if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
960 * RFC 1122: 3.2.2.6 An ICMP_ECHO to broadcast MAY be
961 * silently ignored (we let user decide with a sysctl).
962 * RFC 1122: 3.2.2.8 An ICMP_TIMESTAMP MAY be silently
963 * discarded if to broadcast/multicast.
965 if (icmph->type == ICMP_ECHO &&
966 sysctl_icmp_echo_ignore_broadcasts) {
969 if (icmph->type != ICMP_ECHO &&
970 icmph->type != ICMP_TIMESTAMP &&
971 icmph->type != ICMP_ADDRESS &&
972 icmph->type != ICMP_ADDRESSREPLY) {
977 ICMP_INC_STATS_BH_FIELD(icmp_pointers[icmph->type].input_off);
978 icmp_pointers[icmph->type].handler(skb);
984 ICMP_INC_STATS_BH(IcmpInErrors);
989 * This table is the definition of how we handle ICMP.
991 static struct icmp_control icmp_pointers[NR_ICMP_TYPES + 1] = {
993 .output_off = offsetof(struct icmp_mib, IcmpOutEchoReps),
994 .input_off = offsetof(struct icmp_mib, IcmpInEchoReps),
995 .handler = icmp_discard,
998 .output_off = offsetof(struct icmp_mib, dummy),
999 .input_off = offsetof(struct icmp_mib,IcmpInErrors),
1000 .handler = icmp_discard,
1004 .output_off = offsetof(struct icmp_mib, dummy),
1005 .input_off = offsetof(struct icmp_mib,IcmpInErrors),
1006 .handler = icmp_discard,
1009 [ICMP_DEST_UNREACH] = {
1010 .output_off = offsetof(struct icmp_mib, IcmpOutDestUnreachs),
1011 .input_off = offsetof(struct icmp_mib, IcmpInDestUnreachs),
1012 .handler = icmp_unreach,
1015 [ICMP_SOURCE_QUENCH] = {
1016 .output_off = offsetof(struct icmp_mib, IcmpOutSrcQuenchs),
1017 .input_off = offsetof(struct icmp_mib, IcmpInSrcQuenchs),
1018 .handler = icmp_unreach,
1022 .output_off = offsetof(struct icmp_mib, IcmpOutRedirects),
1023 .input_off = offsetof(struct icmp_mib, IcmpInRedirects),
1024 .handler = icmp_redirect,
1028 .output_off = offsetof(struct icmp_mib, dummy),
1029 .input_off = offsetof(struct icmp_mib, IcmpInErrors),
1030 .handler = icmp_discard,
1034 .output_off = offsetof(struct icmp_mib, dummy),
1035 .input_off = offsetof(struct icmp_mib, IcmpInErrors),
1036 .handler = icmp_discard,
1040 .output_off = offsetof(struct icmp_mib, IcmpOutEchos),
1041 .input_off = offsetof(struct icmp_mib, IcmpInEchos),
1042 .handler = icmp_echo,
1045 .output_off = offsetof(struct icmp_mib, dummy),
1046 .input_off = offsetof(struct icmp_mib, IcmpInErrors),
1047 .handler = icmp_discard,
1051 .output_off = offsetof(struct icmp_mib, dummy),
1052 .input_off = offsetof(struct icmp_mib, IcmpInErrors),
1053 .handler = icmp_discard,
1056 [ICMP_TIME_EXCEEDED] = {
1057 .output_off = offsetof(struct icmp_mib, IcmpOutTimeExcds),
1058 .input_off = offsetof(struct icmp_mib,IcmpInTimeExcds),
1059 .handler = icmp_unreach,
1062 [ICMP_PARAMETERPROB] = {
1063 .output_off = offsetof(struct icmp_mib, IcmpOutParmProbs),
1064 .input_off = offsetof(struct icmp_mib, IcmpInParmProbs),
1065 .handler = icmp_unreach,
1068 [ICMP_TIMESTAMP] = {
1069 .output_off = offsetof(struct icmp_mib, IcmpOutTimestamps),
1070 .input_off = offsetof(struct icmp_mib, IcmpInTimestamps),
1071 .handler = icmp_timestamp,
1073 [ICMP_TIMESTAMPREPLY] = {
1074 .output_off = offsetof(struct icmp_mib, IcmpOutTimestampReps),
1075 .input_off = offsetof(struct icmp_mib, IcmpInTimestampReps),
1076 .handler = icmp_discard,
1078 [ICMP_INFO_REQUEST] = {
1079 .output_off = offsetof(struct icmp_mib, dummy),
1080 .input_off = offsetof(struct icmp_mib, dummy),
1081 .handler = icmp_discard,
1083 [ICMP_INFO_REPLY] = {
1084 .output_off = offsetof(struct icmp_mib, dummy),
1085 .input_off = offsetof(struct icmp_mib, dummy),
1086 .handler = icmp_discard,
1089 .output_off = offsetof(struct icmp_mib, IcmpOutAddrMasks),
1090 .input_off = offsetof(struct icmp_mib, IcmpInAddrMasks),
1091 .handler = icmp_address,
1093 [ICMP_ADDRESSREPLY] = {
1094 .output_off = offsetof(struct icmp_mib, IcmpOutAddrMaskReps),
1095 .input_off = offsetof(struct icmp_mib, IcmpInAddrMaskReps),
1096 .handler = icmp_address_reply,
1100 void __init icmp_init(struct net_proto_family *ops)
1102 struct inet_opt *inet;
1105 for (i = 0; i < NR_CPUS; i++) {
1108 if (!cpu_possible(i))
1111 err = sock_create_kern(PF_INET, SOCK_RAW, IPPROTO_ICMP,
1112 &per_cpu(__icmp_socket, i));
1115 panic("Failed to create the ICMP control socket.\n");
1117 per_cpu(__icmp_socket, i)->sk->sk_allocation = GFP_ATOMIC;
1119 /* Enough space for 2 64K ICMP packets, including
1120 * sk_buff struct overhead.
1122 per_cpu(__icmp_socket, i)->sk->sk_sndbuf =
1123 (2 * ((64 * 1024) + sizeof(struct sk_buff)));
1125 inet = inet_sk(per_cpu(__icmp_socket, i)->sk);
1127 inet->pmtudisc = IP_PMTUDISC_DONT;
1129 /* Unhash it so that IP input processing does not even
1130 * see it, we do not wish this socket to see incoming
1133 per_cpu(__icmp_socket, i)->sk->sk_prot->unhash(per_cpu(__icmp_socket, i)->sk);
1137 EXPORT_SYMBOL(icmp_err_convert);
1138 EXPORT_SYMBOL(icmp_send);
1139 EXPORT_SYMBOL(icmp_statistics);
1140 EXPORT_SYMBOL(xrlim_allow);