SELinux: Convert avc_audit to use lsm_audit.h
[linux-2.6/verdex.git] / net / ipv4 / icmp.c
blob97c410e8438895664a9abdbbf5670b26af01dffa
1 /*
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.
16 * Fixes:
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
23 * call.
24 * Alan Cox : Added 216,128 byte paths to the MTU
25 * code.
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
35 * (RFC 1812).
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
41 * path MTU bug.
42 * Thomas Quinot : ICMP Dest Unreach codes up to 15 are
43 * valid (RFC 1812).
44 * Andi Kleen : Check all packet lengths properly
45 * and moved all kfree_skb() up to
46 * icmp_rcv.
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
54 * at all.
55 * Tristan Greaves : Added sysctl option to ignore bogus
56 * broadcast responses from broken routers.
58 * To Fix:
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>
71 #include <linux/in.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 <net/snmp.h>
78 #include <net/ip.h>
79 #include <net/route.h>
80 #include <net/protocol.h>
81 #include <net/icmp.h>
82 #include <net/tcp.h>
83 #include <net/udp.h>
84 #include <net/raw.h>
85 #include <linux/skbuff.h>
86 #include <net/sock.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>
93 #include <net/xfrm.h>
94 #include <net/inet_common.h>
97 * Build xmit assembly blocks
100 struct icmp_bxm {
101 struct sk_buff *skb;
102 int offset;
103 int data_len;
105 struct {
106 struct icmphdr icmph;
107 __be32 times[3];
108 } data;
109 int head_len;
110 struct ip_options replyopts;
111 unsigned char optbuf[40];
114 /* An array of errno for error messages from dest unreach. */
115 /* RFC 1122: 3.2.2.1 States that NET_UNREACH, HOST_UNREACH and SR_FAILED MUST be considered 'transient errs'. */
117 struct icmp_err icmp_err_convert[] = {
119 .errno = ENETUNREACH, /* ICMP_NET_UNREACH */
120 .fatal = 0,
123 .errno = EHOSTUNREACH, /* ICMP_HOST_UNREACH */
124 .fatal = 0,
127 .errno = ENOPROTOOPT /* ICMP_PROT_UNREACH */,
128 .fatal = 1,
131 .errno = ECONNREFUSED, /* ICMP_PORT_UNREACH */
132 .fatal = 1,
135 .errno = EMSGSIZE, /* ICMP_FRAG_NEEDED */
136 .fatal = 0,
139 .errno = EOPNOTSUPP, /* ICMP_SR_FAILED */
140 .fatal = 0,
143 .errno = ENETUNREACH, /* ICMP_NET_UNKNOWN */
144 .fatal = 1,
147 .errno = EHOSTDOWN, /* ICMP_HOST_UNKNOWN */
148 .fatal = 1,
151 .errno = ENONET, /* ICMP_HOST_ISOLATED */
152 .fatal = 1,
155 .errno = ENETUNREACH, /* ICMP_NET_ANO */
156 .fatal = 1,
159 .errno = EHOSTUNREACH, /* ICMP_HOST_ANO */
160 .fatal = 1,
163 .errno = ENETUNREACH, /* ICMP_NET_UNR_TOS */
164 .fatal = 0,
167 .errno = EHOSTUNREACH, /* ICMP_HOST_UNR_TOS */
168 .fatal = 0,
171 .errno = EHOSTUNREACH, /* ICMP_PKT_FILTERED */
172 .fatal = 1,
175 .errno = EHOSTUNREACH, /* ICMP_PREC_VIOLATION */
176 .fatal = 1,
179 .errno = EHOSTUNREACH, /* ICMP_PREC_CUTOFF */
180 .fatal = 1,
185 * ICMP control array. This specifies what to do with each ICMP.
188 struct icmp_control {
189 void (*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 net->ipv4.icmp_sk[smp_processor_id()];
207 static inline struct sock *icmp_xmit_lock(struct net *net)
209 struct sock *sk;
211 local_bh_disable();
213 sk = icmp_sk(net);
215 if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
216 /* This can happen if the output path signals a
217 * dst_link_failure() for an outgoing ICMP packet.
219 local_bh_enable();
220 return NULL;
222 return sk;
225 static inline void icmp_xmit_unlock(struct sock *sk)
227 spin_unlock_bh(&sk->sk_lock.slock);
231 * Send an ICMP frame.
235 * Check transmit rate limitation for given message.
236 * The rate information is held in the destination cache now.
237 * This function is generic and could be used for other purposes
238 * too. It uses a Token bucket filter as suggested by Alexey Kuznetsov.
240 * Note that the same dst_entry fields are modified by functions in
241 * route.c too, but these work for packet destinations while xrlim_allow
242 * works for icmp destinations. This means the rate limiting information
243 * for one "ip object" is shared - and these ICMPs are twice limited:
244 * by source and by destination.
246 * RFC 1812: 4.3.2.8 SHOULD be able to limit error message rate
247 * SHOULD allow setting of rate limits
249 * Shared between ICMPv4 and ICMPv6.
251 #define XRLIM_BURST_FACTOR 6
252 int xrlim_allow(struct dst_entry *dst, int timeout)
254 unsigned long now, token = dst->rate_tokens;
255 int rc = 0;
257 now = jiffies;
258 token += now - dst->rate_last;
259 dst->rate_last = now;
260 if (token > XRLIM_BURST_FACTOR * timeout)
261 token = XRLIM_BURST_FACTOR * timeout;
262 if (token >= timeout) {
263 token -= timeout;
264 rc = 1;
266 dst->rate_tokens = token;
267 return rc;
270 static inline int icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
271 int type, int code)
273 struct dst_entry *dst = &rt->u.dst;
274 int rc = 1;
276 if (type > NR_ICMP_TYPES)
277 goto out;
279 /* Don't limit PMTU discovery. */
280 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
281 goto out;
283 /* No rate limit on loopback */
284 if (dst->dev && (dst->dev->flags&IFF_LOOPBACK))
285 goto out;
287 /* Limit if icmp type is enabled in ratemask. */
288 if ((1 << type) & net->ipv4.sysctl_icmp_ratemask)
289 rc = xrlim_allow(dst, net->ipv4.sysctl_icmp_ratelimit);
290 out:
291 return rc;
295 * Maintain the counters used in the SNMP statistics for outgoing ICMP
297 void icmp_out_count(struct net *net, unsigned char type)
299 ICMPMSGOUT_INC_STATS(net, type);
300 ICMP_INC_STATS(net, ICMP_MIB_OUTMSGS);
304 * Checksum each fragment, and on the first include the headers and final
305 * checksum.
307 static int icmp_glue_bits(void *from, char *to, int offset, int len, int odd,
308 struct sk_buff *skb)
310 struct icmp_bxm *icmp_param = (struct icmp_bxm *)from;
311 __wsum csum;
313 csum = skb_copy_and_csum_bits(icmp_param->skb,
314 icmp_param->offset + offset,
315 to, len, 0);
317 skb->csum = csum_block_add(skb->csum, csum, odd);
318 if (icmp_pointers[icmp_param->data.icmph.type].error)
319 nf_ct_attach(skb, icmp_param->skb);
320 return 0;
323 static void icmp_push_reply(struct icmp_bxm *icmp_param,
324 struct ipcm_cookie *ipc, struct rtable **rt)
326 struct sock *sk;
327 struct sk_buff *skb;
329 sk = icmp_sk(dev_net((*rt)->u.dst.dev));
330 if (ip_append_data(sk, icmp_glue_bits, icmp_param,
331 icmp_param->data_len+icmp_param->head_len,
332 icmp_param->head_len,
333 ipc, rt, MSG_DONTWAIT) < 0)
334 ip_flush_pending_frames(sk);
335 else if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) {
336 struct icmphdr *icmph = icmp_hdr(skb);
337 __wsum csum = 0;
338 struct sk_buff *skb1;
340 skb_queue_walk(&sk->sk_write_queue, skb1) {
341 csum = csum_add(csum, skb1->csum);
343 csum = csum_partial_copy_nocheck((void *)&icmp_param->data,
344 (char *)icmph,
345 icmp_param->head_len, csum);
346 icmph->checksum = csum_fold(csum);
347 skb->ip_summed = CHECKSUM_NONE;
348 ip_push_pending_frames(sk);
353 * Driving logic for building and sending ICMP messages.
356 static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
358 struct ipcm_cookie ipc;
359 struct rtable *rt = skb_rtable(skb);
360 struct net *net = dev_net(rt->u.dst.dev);
361 struct sock *sk;
362 struct inet_sock *inet;
363 __be32 daddr;
365 if (ip_options_echo(&icmp_param->replyopts, skb))
366 return;
368 sk = icmp_xmit_lock(net);
369 if (sk == NULL)
370 return;
371 inet = inet_sk(sk);
373 icmp_param->data.icmph.checksum = 0;
375 inet->tos = ip_hdr(skb)->tos;
376 daddr = ipc.addr = rt->rt_src;
377 ipc.opt = NULL;
378 ipc.shtx.flags = 0;
379 if (icmp_param->replyopts.optlen) {
380 ipc.opt = &icmp_param->replyopts;
381 if (ipc.opt->srr)
382 daddr = icmp_param->replyopts.faddr;
385 struct flowi fl = { .nl_u = { .ip4_u =
386 { .daddr = daddr,
387 .saddr = rt->rt_spec_dst,
388 .tos = RT_TOS(ip_hdr(skb)->tos) } },
389 .proto = IPPROTO_ICMP };
390 security_skb_classify_flow(skb, &fl);
391 if (ip_route_output_key(net, &rt, &fl))
392 goto out_unlock;
394 if (icmpv4_xrlim_allow(net, rt, icmp_param->data.icmph.type,
395 icmp_param->data.icmph.code))
396 icmp_push_reply(icmp_param, &ipc, &rt);
397 ip_rt_put(rt);
398 out_unlock:
399 icmp_xmit_unlock(sk);
404 * Send an ICMP message in response to a situation
406 * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header.
407 * MAY send more (we do).
408 * MUST NOT change this header information.
409 * MUST NOT reply to a multicast/broadcast IP address.
410 * MUST NOT reply to a multicast/broadcast MAC address.
411 * MUST reply to only the first fragment.
414 void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
416 struct iphdr *iph;
417 int room;
418 struct icmp_bxm icmp_param;
419 struct rtable *rt = skb_rtable(skb_in);
420 struct ipcm_cookie ipc;
421 __be32 saddr;
422 u8 tos;
423 struct net *net;
424 struct sock *sk;
426 if (!rt)
427 goto out;
428 net = dev_net(rt->u.dst.dev);
431 * Find the original header. It is expected to be valid, of course.
432 * Check this, icmp_send is called from the most obscure devices
433 * sometimes.
435 iph = ip_hdr(skb_in);
437 if ((u8 *)iph < skb_in->head ||
438 (skb_in->network_header + sizeof(*iph)) > skb_in->tail)
439 goto out;
442 * No replies to physical multicast/broadcast
444 if (skb_in->pkt_type != PACKET_HOST)
445 goto out;
448 * Now check at the protocol level
450 if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
451 goto out;
454 * Only reply to fragment 0. We byte re-order the constant
455 * mask for efficiency.
457 if (iph->frag_off & htons(IP_OFFSET))
458 goto out;
461 * If we send an ICMP error to an ICMP error a mess would result..
463 if (icmp_pointers[type].error) {
465 * We are an error, check if we are replying to an
466 * ICMP error
468 if (iph->protocol == IPPROTO_ICMP) {
469 u8 _inner_type, *itp;
471 itp = skb_header_pointer(skb_in,
472 skb_network_header(skb_in) +
473 (iph->ihl << 2) +
474 offsetof(struct icmphdr,
475 type) -
476 skb_in->data,
477 sizeof(_inner_type),
478 &_inner_type);
479 if (itp == NULL)
480 goto out;
483 * Assume any unknown ICMP type is an error. This
484 * isn't specified by the RFC, but think about it..
486 if (*itp > NR_ICMP_TYPES ||
487 icmp_pointers[*itp].error)
488 goto out;
492 sk = icmp_xmit_lock(net);
493 if (sk == NULL)
494 return;
497 * Construct source address and options.
500 saddr = iph->daddr;
501 if (!(rt->rt_flags & RTCF_LOCAL)) {
502 struct net_device *dev = NULL;
504 if (rt->fl.iif &&
505 net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr)
506 dev = dev_get_by_index(net, rt->fl.iif);
508 if (dev) {
509 saddr = inet_select_addr(dev, 0, RT_SCOPE_LINK);
510 dev_put(dev);
511 } else
512 saddr = 0;
515 tos = icmp_pointers[type].error ? ((iph->tos & IPTOS_TOS_MASK) |
516 IPTOS_PREC_INTERNETCONTROL) :
517 iph->tos;
519 if (ip_options_echo(&icmp_param.replyopts, skb_in))
520 goto out_unlock;
524 * Prepare data for ICMP header.
527 icmp_param.data.icmph.type = type;
528 icmp_param.data.icmph.code = code;
529 icmp_param.data.icmph.un.gateway = info;
530 icmp_param.data.icmph.checksum = 0;
531 icmp_param.skb = skb_in;
532 icmp_param.offset = skb_network_offset(skb_in);
533 inet_sk(sk)->tos = tos;
534 ipc.addr = iph->saddr;
535 ipc.opt = &icmp_param.replyopts;
536 ipc.shtx.flags = 0;
539 struct flowi fl = {
540 .nl_u = {
541 .ip4_u = {
542 .daddr = icmp_param.replyopts.srr ?
543 icmp_param.replyopts.faddr :
544 iph->saddr,
545 .saddr = saddr,
546 .tos = RT_TOS(tos)
549 .proto = IPPROTO_ICMP,
550 .uli_u = {
551 .icmpt = {
552 .type = type,
553 .code = code
557 int err;
558 struct rtable *rt2;
560 security_skb_classify_flow(skb_in, &fl);
561 if (__ip_route_output_key(net, &rt, &fl))
562 goto out_unlock;
564 /* No need to clone since we're just using its address. */
565 rt2 = rt;
567 err = xfrm_lookup(net, (struct dst_entry **)&rt, &fl, NULL, 0);
568 switch (err) {
569 case 0:
570 if (rt != rt2)
571 goto route_done;
572 break;
573 case -EPERM:
574 rt = NULL;
575 break;
576 default:
577 goto out_unlock;
580 if (xfrm_decode_session_reverse(skb_in, &fl, AF_INET))
581 goto relookup_failed;
583 if (inet_addr_type(net, fl.fl4_src) == RTN_LOCAL)
584 err = __ip_route_output_key(net, &rt2, &fl);
585 else {
586 struct flowi fl2 = {};
587 struct dst_entry *odst;
589 fl2.fl4_dst = fl.fl4_src;
590 if (ip_route_output_key(net, &rt2, &fl2))
591 goto relookup_failed;
593 /* Ugh! */
594 odst = skb_dst(skb_in);
595 err = ip_route_input(skb_in, fl.fl4_dst, fl.fl4_src,
596 RT_TOS(tos), rt2->u.dst.dev);
598 dst_release(&rt2->u.dst);
599 rt2 = skb_rtable(skb_in);
600 skb_dst_set(skb_in, odst);
603 if (err)
604 goto relookup_failed;
606 err = xfrm_lookup(net, (struct dst_entry **)&rt2, &fl, NULL,
607 XFRM_LOOKUP_ICMP);
608 switch (err) {
609 case 0:
610 dst_release(&rt->u.dst);
611 rt = rt2;
612 break;
613 case -EPERM:
614 goto ende;
615 default:
616 relookup_failed:
617 if (!rt)
618 goto out_unlock;
619 break;
623 route_done:
624 if (!icmpv4_xrlim_allow(net, rt, type, code))
625 goto ende;
627 /* RFC says return as much as we can without exceeding 576 bytes. */
629 room = dst_mtu(&rt->u.dst);
630 if (room > 576)
631 room = 576;
632 room -= sizeof(struct iphdr) + icmp_param.replyopts.optlen;
633 room -= sizeof(struct icmphdr);
635 icmp_param.data_len = skb_in->len - icmp_param.offset;
636 if (icmp_param.data_len > room)
637 icmp_param.data_len = room;
638 icmp_param.head_len = sizeof(struct icmphdr);
640 icmp_push_reply(&icmp_param, &ipc, &rt);
641 ende:
642 ip_rt_put(rt);
643 out_unlock:
644 icmp_xmit_unlock(sk);
645 out:;
650 * Handle ICMP_DEST_UNREACH, ICMP_TIME_EXCEED, and ICMP_QUENCH.
653 static void icmp_unreach(struct sk_buff *skb)
655 struct iphdr *iph;
656 struct icmphdr *icmph;
657 int hash, protocol;
658 struct net_protocol *ipprot;
659 u32 info = 0;
660 struct net *net;
662 net = dev_net(skb_dst(skb)->dev);
665 * Incomplete header ?
666 * Only checks for the IP header, there should be an
667 * additional check for longer headers in upper levels.
670 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
671 goto out_err;
673 icmph = icmp_hdr(skb);
674 iph = (struct iphdr *)skb->data;
676 if (iph->ihl < 5) /* Mangled header, drop. */
677 goto out_err;
679 if (icmph->type == ICMP_DEST_UNREACH) {
680 switch (icmph->code & 15) {
681 case ICMP_NET_UNREACH:
682 case ICMP_HOST_UNREACH:
683 case ICMP_PROT_UNREACH:
684 case ICMP_PORT_UNREACH:
685 break;
686 case ICMP_FRAG_NEEDED:
687 if (ipv4_config.no_pmtu_disc) {
688 LIMIT_NETDEBUG(KERN_INFO "ICMP: %pI4: fragmentation needed and DF set.\n",
689 &iph->daddr);
690 } else {
691 info = ip_rt_frag_needed(net, iph,
692 ntohs(icmph->un.frag.mtu),
693 skb->dev);
694 if (!info)
695 goto out;
697 break;
698 case ICMP_SR_FAILED:
699 LIMIT_NETDEBUG(KERN_INFO "ICMP: %pI4: Source Route Failed.\n",
700 &iph->daddr);
701 break;
702 default:
703 break;
705 if (icmph->code > NR_ICMP_UNREACH)
706 goto out;
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
714 * header.
715 * RFC 1122: 3.2.2.1 MUST pass ICMP unreach messages to the
716 * transport layer.
717 * RFC 1122: 3.2.2.2 MUST pass ICMP time expired messages to
718 * transport layer.
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) {
730 if (net_ratelimit())
731 printk(KERN_WARNING "%pI4 sent an invalid ICMP "
732 "type %u, code %u "
733 "error to a broadcast: %pI4 on %s\n",
734 &ip_hdr(skb)->saddr,
735 icmph->type, icmph->code,
736 &iph->daddr,
737 skb->dev->name);
738 goto out;
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))
745 goto out;
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);
756 rcu_read_lock();
757 ipprot = rcu_dereference(inet_protos[hash]);
758 if (ipprot && ipprot->err_handler)
759 ipprot->err_handler(skb, info);
760 rcu_read_unlock();
762 out:
763 return;
764 out_err:
765 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
766 goto out;
771 * Handle ICMP_REDIRECT.
774 static void icmp_redirect(struct sk_buff *skb)
776 struct iphdr *iph;
778 if (skb->len < sizeof(struct iphdr))
779 goto out_err;
782 * Get the copied header of the packet that caused the redirect
784 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
785 goto out;
787 iph = (struct iphdr *)skb->data;
789 switch (icmp_hdr(skb)->code & 7) {
790 case ICMP_REDIR_NET:
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);
800 break;
802 out:
803 return;
804 out_err:
805 ICMP_INC_STATS_BH(dev_net(skb->dev), ICMP_MIB_INERRORS);
806 goto out;
810 * Handle ICMP_ECHO ("ping") requests.
812 * RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo
813 * requests.
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)
823 struct net *net;
825 net = dev_net(skb_dst(skb)->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)
848 struct timespec tv;
849 struct icmp_bxm icmp_param;
851 * Too short.
853 if (skb->len < 4)
854 goto out_err;
857 * Fill in the current time as ms since midnight UT:
859 getnstimeofday(&tv);
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))
864 BUG();
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);
873 out:
874 return;
875 out_err:
876 ICMP_INC_STATS_BH(dev_net(skb_dst(skb)->dev), ICMP_MIB_INERRORS);
877 goto out;
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(),
889 * I guess. -- MS
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
908 * any case. --ANK
910 * Furthermore you can do it with a usermode address agent program
911 * anyway...
914 static void icmp_address(struct sk_buff *skb)
916 #if 0
917 if (net_ratelimit())
918 printk(KERN_DEBUG "a guy asks for address mask. Who is it?\n");
919 #endif
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(skb);
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))
935 goto out;
937 in_dev = in_dev_get(dev);
938 if (!in_dev)
939 goto out;
940 rcu_read_lock();
941 if (in_dev->ifa_list &&
942 IN_DEV_LOG_MARTIANS(in_dev) &&
943 IN_DEV_FORWARD(in_dev)) {
944 __be32 _mask, *mp;
946 mp = skb_header_pointer(skb, 0, sizeof(_mask), &_mask);
947 BUG_ON(mp == NULL);
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))
951 break;
953 if (!ifa && net_ratelimit()) {
954 printk(KERN_INFO "Wrong address mask %pI4 from %s/%pI4\n",
955 mp, dev->name, &rt->rt_src);
958 rcu_read_unlock();
959 in_dev_put(in_dev);
960 out:;
963 static void icmp_discard(struct sk_buff *skb)
968 * Deal with incoming ICMP packets.
970 int icmp_rcv(struct sk_buff *skb)
972 struct icmphdr *icmph;
973 struct rtable *rt = skb_rtable(skb);
974 struct net *net = dev_net(rt->u.dst.dev);
976 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
977 struct sec_path *sp = skb_sec_path(skb);
978 int nh;
980 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
981 XFRM_STATE_ICMP))
982 goto drop;
984 if (!pskb_may_pull(skb, sizeof(*icmph) + sizeof(struct iphdr)))
985 goto drop;
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))
991 goto drop;
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))
1001 break;
1002 /* fall through */
1003 case CHECKSUM_NONE:
1004 skb->csum = 0;
1005 if (__skb_checksum_complete(skb))
1006 goto error;
1009 if (!pskb_pull(skb, sizeof(*icmph)))
1010 goto error;
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
1019 * discarded.
1021 if (icmph->type > NR_ICMP_TYPES)
1022 goto error;
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) {
1039 goto error;
1041 if (icmph->type != ICMP_ECHO &&
1042 icmph->type != ICMP_TIMESTAMP &&
1043 icmph->type != ICMP_ADDRESS &&
1044 icmph->type != ICMP_ADDRESSREPLY) {
1045 goto error;
1049 icmp_pointers[icmph->type].handler(skb);
1051 drop:
1052 kfree_skb(skb);
1053 return 0;
1054 error:
1055 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
1056 goto drop;
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,
1066 [1] = {
1067 .handler = icmp_discard,
1068 .error = 1,
1070 [2] = {
1071 .handler = icmp_discard,
1072 .error = 1,
1074 [ICMP_DEST_UNREACH] = {
1075 .handler = icmp_unreach,
1076 .error = 1,
1078 [ICMP_SOURCE_QUENCH] = {
1079 .handler = icmp_unreach,
1080 .error = 1,
1082 [ICMP_REDIRECT] = {
1083 .handler = icmp_redirect,
1084 .error = 1,
1086 [6] = {
1087 .handler = icmp_discard,
1088 .error = 1,
1090 [7] = {
1091 .handler = icmp_discard,
1092 .error = 1,
1094 [ICMP_ECHO] = {
1095 .handler = icmp_echo,
1097 [9] = {
1098 .handler = icmp_discard,
1099 .error = 1,
1101 [10] = {
1102 .handler = icmp_discard,
1103 .error = 1,
1105 [ICMP_TIME_EXCEEDED] = {
1106 .handler = icmp_unreach,
1107 .error = 1,
1109 [ICMP_PARAMETERPROB] = {
1110 .handler = icmp_unreach,
1111 .error = 1,
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,
1125 [ICMP_ADDRESS] = {
1126 .handler = icmp_address,
1128 [ICMP_ADDRESSREPLY] = {
1129 .handler = icmp_address_reply,
1133 static void __net_exit icmp_sk_exit(struct net *net)
1135 int i;
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)
1145 int i, err;
1147 net->ipv4.icmp_sk =
1148 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL);
1149 if (net->ipv4.icmp_sk == NULL)
1150 return -ENOMEM;
1152 for_each_possible_cpu(i) {
1153 struct sock *sk;
1155 err = inet_ctl_sock_create(&sk, PF_INET,
1156 SOCK_RAW, IPPROTO_ICMP, net);
1157 if (err < 0)
1158 goto fail;
1160 net->ipv4.icmp_sk[i] = sk;
1162 /* Enough space for 2 64K ICMP packets, including
1163 * sk_buff struct overhead.
1165 sk->sk_sndbuf =
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.
1185 * default:
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;
1194 return 0;
1196 fail:
1197 for_each_possible_cpu(i)
1198 inet_ctl_sock_destroy(net->ipv4.icmp_sk[i]);
1199 kfree(net->ipv4.icmp_sk);
1200 return err;
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_subsys(&icmp_sk_ops);
1213 EXPORT_SYMBOL(icmp_err_convert);
1214 EXPORT_SYMBOL(icmp_send);
1215 EXPORT_SYMBOL(xrlim_allow);