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/module.h>
68 #include <linux/types.h>
69 #include <linux/jiffies.h>
70 #include <linux/kernel.h>
71 #include <linux/fcntl.h>
72 #include <linux/socket.h>
74 #include <linux/inet.h>
75 #include <linux/inetdevice.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>
98 * Build xmit assembly blocks
107 struct icmphdr icmph
;
111 struct ip_options replyopts
;
112 unsigned char optbuf
[40];
118 DEFINE_SNMP_STAT(struct icmp_mib
, icmp_statistics
) __read_mostly
;
119 DEFINE_SNMP_STAT(struct icmpmsg_mib
, icmpmsg_statistics
) __read_mostly
;
121 /* An array of errno for error messages from dest unreach. */
122 /* RFC 1122: 3.2.2.1 States that NET_UNREACH, HOST_UNREACH and SR_FAILED MUST be considered 'transient errs'. */
124 struct icmp_err icmp_err_convert
[] = {
126 .errno
= ENETUNREACH
, /* ICMP_NET_UNREACH */
130 .errno
= EHOSTUNREACH
, /* ICMP_HOST_UNREACH */
134 .errno
= ENOPROTOOPT
/* ICMP_PROT_UNREACH */,
138 .errno
= ECONNREFUSED
, /* ICMP_PORT_UNREACH */
142 .errno
= EMSGSIZE
, /* ICMP_FRAG_NEEDED */
146 .errno
= EOPNOTSUPP
, /* ICMP_SR_FAILED */
150 .errno
= ENETUNREACH
, /* ICMP_NET_UNKNOWN */
154 .errno
= EHOSTDOWN
, /* ICMP_HOST_UNKNOWN */
158 .errno
= ENONET
, /* ICMP_HOST_ISOLATED */
162 .errno
= ENETUNREACH
, /* ICMP_NET_ANO */
166 .errno
= EHOSTUNREACH
, /* ICMP_HOST_ANO */
170 .errno
= ENETUNREACH
, /* ICMP_NET_UNR_TOS */
174 .errno
= EHOSTUNREACH
, /* ICMP_HOST_UNR_TOS */
178 .errno
= EHOSTUNREACH
, /* ICMP_PKT_FILTERED */
182 .errno
= EHOSTUNREACH
, /* ICMP_PREC_VIOLATION */
186 .errno
= EHOSTUNREACH
, /* ICMP_PREC_CUTOFF */
191 /* Control parameters for ECHO replies. */
192 int sysctl_icmp_echo_ignore_all __read_mostly
;
193 int sysctl_icmp_echo_ignore_broadcasts __read_mostly
= 1;
195 /* Control parameter - ignore bogus broadcast responses? */
196 int sysctl_icmp_ignore_bogus_error_responses __read_mostly
= 1;
199 * Configurable global rate limit.
201 * ratelimit defines tokens/packet consumed for dst->rate_token bucket
202 * ratemask defines which icmp types are ratelimited by setting
206 * dest unreachable (3), source quench (4),
207 * time exceeded (11), parameter problem (12)
210 int sysctl_icmp_ratelimit __read_mostly
= 1 * HZ
;
211 int sysctl_icmp_ratemask __read_mostly
= 0x1818;
212 int sysctl_icmp_errors_use_inbound_ifaddr __read_mostly
;
215 * ICMP control array. This specifies what to do with each ICMP.
218 struct icmp_control
{
219 void (*handler
)(struct sk_buff
*skb
);
220 short error
; /* This ICMP is classed as an error message */
223 static const struct icmp_control icmp_pointers
[NR_ICMP_TYPES
+1];
226 * The ICMP socket(s). This is the most convenient way to flow control
227 * our ICMP output as well as maintain a clean interface throughout
228 * all layers. All Socketless IP sends will soon be gone.
230 * On SMP we have one ICMP socket per-cpu.
232 static struct sock
*icmp_sk(struct net
*net
)
234 return net
->ipv4
.icmp_sk
[smp_processor_id()];
237 static inline int icmp_xmit_lock(struct sock
*sk
)
241 if (unlikely(!spin_trylock(&sk
->sk_lock
.slock
))) {
242 /* This can happen if the output path signals a
243 * dst_link_failure() for an outgoing ICMP packet.
251 static inline void icmp_xmit_unlock(struct sock
*sk
)
253 spin_unlock_bh(&sk
->sk_lock
.slock
);
257 * Send an ICMP frame.
261 * Check transmit rate limitation for given message.
262 * The rate information is held in the destination cache now.
263 * This function is generic and could be used for other purposes
264 * too. It uses a Token bucket filter as suggested by Alexey Kuznetsov.
266 * Note that the same dst_entry fields are modified by functions in
267 * route.c too, but these work for packet destinations while xrlim_allow
268 * works for icmp destinations. This means the rate limiting information
269 * for one "ip object" is shared - and these ICMPs are twice limited:
270 * by source and by destination.
272 * RFC 1812: 4.3.2.8 SHOULD be able to limit error message rate
273 * SHOULD allow setting of rate limits
275 * Shared between ICMPv4 and ICMPv6.
277 #define XRLIM_BURST_FACTOR 6
278 int xrlim_allow(struct dst_entry
*dst
, int timeout
)
280 unsigned long now
, token
= dst
->rate_tokens
;
284 token
+= now
- dst
->rate_last
;
285 dst
->rate_last
= now
;
286 if (token
> XRLIM_BURST_FACTOR
* timeout
)
287 token
= XRLIM_BURST_FACTOR
* timeout
;
288 if (token
>= timeout
) {
292 dst
->rate_tokens
= token
;
296 static inline int icmpv4_xrlim_allow(struct rtable
*rt
, int type
, int code
)
298 struct dst_entry
*dst
= &rt
->u
.dst
;
301 if (type
> NR_ICMP_TYPES
)
304 /* Don't limit PMTU discovery. */
305 if (type
== ICMP_DEST_UNREACH
&& code
== ICMP_FRAG_NEEDED
)
308 /* No rate limit on loopback */
309 if (dst
->dev
&& (dst
->dev
->flags
&IFF_LOOPBACK
))
312 /* Limit if icmp type is enabled in ratemask. */
313 if ((1 << type
) & sysctl_icmp_ratemask
)
314 rc
= xrlim_allow(dst
, sysctl_icmp_ratelimit
);
320 * Maintain the counters used in the SNMP statistics for outgoing ICMP
322 void icmp_out_count(unsigned char type
)
324 ICMPMSGOUT_INC_STATS(type
);
325 ICMP_INC_STATS(ICMP_MIB_OUTMSGS
);
329 * Checksum each fragment, and on the first include the headers and final
332 static int icmp_glue_bits(void *from
, char *to
, int offset
, int len
, int odd
,
335 struct icmp_bxm
*icmp_param
= (struct icmp_bxm
*)from
;
338 csum
= skb_copy_and_csum_bits(icmp_param
->skb
,
339 icmp_param
->offset
+ offset
,
342 skb
->csum
= csum_block_add(skb
->csum
, csum
, odd
);
343 if (icmp_pointers
[icmp_param
->data
.icmph
.type
].error
)
344 nf_ct_attach(skb
, icmp_param
->skb
);
348 static void icmp_push_reply(struct icmp_bxm
*icmp_param
,
349 struct ipcm_cookie
*ipc
, struct rtable
*rt
)
354 sk
= icmp_sk(rt
->u
.dst
.dev
->nd_net
);
355 if (ip_append_data(sk
, icmp_glue_bits
, icmp_param
,
356 icmp_param
->data_len
+icmp_param
->head_len
,
357 icmp_param
->head_len
,
358 ipc
, rt
, MSG_DONTWAIT
) < 0)
359 ip_flush_pending_frames(sk
);
360 else if ((skb
= skb_peek(&sk
->sk_write_queue
)) != NULL
) {
361 struct icmphdr
*icmph
= icmp_hdr(skb
);
363 struct sk_buff
*skb1
;
365 skb_queue_walk(&sk
->sk_write_queue
, skb1
) {
366 csum
= csum_add(csum
, skb1
->csum
);
368 csum
= csum_partial_copy_nocheck((void *)&icmp_param
->data
,
370 icmp_param
->head_len
, csum
);
371 icmph
->checksum
= csum_fold(csum
);
372 skb
->ip_summed
= CHECKSUM_NONE
;
373 ip_push_pending_frames(sk
);
378 * Driving logic for building and sending ICMP messages.
381 static void icmp_reply(struct icmp_bxm
*icmp_param
, struct sk_buff
*skb
)
383 struct ipcm_cookie ipc
;
384 struct rtable
*rt
= skb
->rtable
;
385 struct net
*net
= rt
->u
.dst
.dev
->nd_net
;
386 struct sock
*sk
= icmp_sk(net
);
387 struct inet_sock
*inet
= inet_sk(sk
);
390 if (ip_options_echo(&icmp_param
->replyopts
, skb
))
393 if (icmp_xmit_lock(sk
))
396 icmp_param
->data
.icmph
.checksum
= 0;
398 inet
->tos
= ip_hdr(skb
)->tos
;
399 daddr
= ipc
.addr
= rt
->rt_src
;
401 if (icmp_param
->replyopts
.optlen
) {
402 ipc
.opt
= &icmp_param
->replyopts
;
404 daddr
= icmp_param
->replyopts
.faddr
;
407 struct flowi fl
= { .nl_u
= { .ip4_u
=
409 .saddr
= rt
->rt_spec_dst
,
410 .tos
= RT_TOS(ip_hdr(skb
)->tos
) } },
411 .proto
= IPPROTO_ICMP
};
412 security_skb_classify_flow(skb
, &fl
);
413 if (ip_route_output_key(net
, &rt
, &fl
))
416 if (icmpv4_xrlim_allow(rt
, icmp_param
->data
.icmph
.type
,
417 icmp_param
->data
.icmph
.code
))
418 icmp_push_reply(icmp_param
, &ipc
, rt
);
421 icmp_xmit_unlock(sk
);
426 * Send an ICMP message in response to a situation
428 * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header.
429 * MAY send more (we do).
430 * MUST NOT change this header information.
431 * MUST NOT reply to a multicast/broadcast IP address.
432 * MUST NOT reply to a multicast/broadcast MAC address.
433 * MUST reply to only the first fragment.
436 void icmp_send(struct sk_buff
*skb_in
, int type
, int code
, __be32 info
)
440 struct icmp_bxm icmp_param
;
441 struct rtable
*rt
= skb_in
->rtable
;
442 struct ipcm_cookie ipc
;
450 net
= rt
->u
.dst
.dev
->nd_net
;
454 * Find the original header. It is expected to be valid, of course.
455 * Check this, icmp_send is called from the most obscure devices
458 iph
= ip_hdr(skb_in
);
460 if ((u8
*)iph
< skb_in
->head
||
461 (skb_in
->network_header
+ sizeof(*iph
)) > skb_in
->tail
)
465 * No replies to physical multicast/broadcast
467 if (skb_in
->pkt_type
!= PACKET_HOST
)
471 * Now check at the protocol level
473 if (rt
->rt_flags
& (RTCF_BROADCAST
| RTCF_MULTICAST
))
477 * Only reply to fragment 0. We byte re-order the constant
478 * mask for efficiency.
480 if (iph
->frag_off
& htons(IP_OFFSET
))
484 * If we send an ICMP error to an ICMP error a mess would result..
486 if (icmp_pointers
[type
].error
) {
488 * We are an error, check if we are replying to an
491 if (iph
->protocol
== IPPROTO_ICMP
) {
492 u8 _inner_type
, *itp
;
494 itp
= skb_header_pointer(skb_in
,
495 skb_network_header(skb_in
) +
497 offsetof(struct icmphdr
,
506 * Assume any unknown ICMP type is an error. This
507 * isn't specified by the RFC, but think about it..
509 if (*itp
> NR_ICMP_TYPES
||
510 icmp_pointers
[*itp
].error
)
515 if (icmp_xmit_lock(sk
))
519 * Construct source address and options.
523 if (!(rt
->rt_flags
& RTCF_LOCAL
)) {
524 struct net_device
*dev
= NULL
;
526 if (rt
->fl
.iif
&& sysctl_icmp_errors_use_inbound_ifaddr
)
527 dev
= dev_get_by_index(net
, rt
->fl
.iif
);
530 saddr
= inet_select_addr(dev
, 0, RT_SCOPE_LINK
);
536 tos
= icmp_pointers
[type
].error
? ((iph
->tos
& IPTOS_TOS_MASK
) |
537 IPTOS_PREC_INTERNETCONTROL
) :
540 if (ip_options_echo(&icmp_param
.replyopts
, skb_in
))
545 * Prepare data for ICMP header.
548 icmp_param
.data
.icmph
.type
= type
;
549 icmp_param
.data
.icmph
.code
= code
;
550 icmp_param
.data
.icmph
.un
.gateway
= info
;
551 icmp_param
.data
.icmph
.checksum
= 0;
552 icmp_param
.skb
= skb_in
;
553 icmp_param
.offset
= skb_network_offset(skb_in
);
554 inet_sk(sk
)->tos
= tos
;
555 ipc
.addr
= iph
->saddr
;
556 ipc
.opt
= &icmp_param
.replyopts
;
562 .daddr
= icmp_param
.replyopts
.srr
?
563 icmp_param
.replyopts
.faddr
:
569 .proto
= IPPROTO_ICMP
,
580 security_skb_classify_flow(skb_in
, &fl
);
581 if (__ip_route_output_key(net
, &rt
, &fl
))
584 /* No need to clone since we're just using its address. */
587 err
= xfrm_lookup((struct dst_entry
**)&rt
, &fl
, NULL
, 0);
600 if (xfrm_decode_session_reverse(skb_in
, &fl
, AF_INET
))
603 if (inet_addr_type(net
, fl
.fl4_src
) == RTN_LOCAL
)
604 err
= __ip_route_output_key(net
, &rt2
, &fl
);
606 struct flowi fl2
= {};
607 struct dst_entry
*odst
;
609 fl2
.fl4_dst
= fl
.fl4_src
;
610 if (ip_route_output_key(net
, &rt2
, &fl2
))
615 err
= ip_route_input(skb_in
, fl
.fl4_dst
, fl
.fl4_src
,
616 RT_TOS(tos
), rt2
->u
.dst
.dev
);
618 dst_release(&rt2
->u
.dst
);
619 rt2
= skb_in
->rtable
;
626 err
= xfrm_lookup((struct dst_entry
**)&rt2
, &fl
, NULL
,
628 if (err
== -ENOENT
) {
634 dst_release(&rt
->u
.dst
);
642 if (!icmpv4_xrlim_allow(rt
, type
, code
))
645 /* RFC says return as much as we can without exceeding 576 bytes. */
647 room
= dst_mtu(&rt
->u
.dst
);
650 room
-= sizeof(struct iphdr
) + icmp_param
.replyopts
.optlen
;
651 room
-= sizeof(struct icmphdr
);
653 icmp_param
.data_len
= skb_in
->len
- icmp_param
.offset
;
654 if (icmp_param
.data_len
> room
)
655 icmp_param
.data_len
= room
;
656 icmp_param
.head_len
= sizeof(struct icmphdr
);
658 icmp_push_reply(&icmp_param
, &ipc
, rt
);
662 icmp_xmit_unlock(sk
);
668 * Handle ICMP_DEST_UNREACH, ICMP_TIME_EXCEED, and ICMP_QUENCH.
671 static void icmp_unreach(struct sk_buff
*skb
)
674 struct icmphdr
*icmph
;
676 struct net_protocol
*ipprot
;
680 net
= skb
->dst
->dev
->nd_net
;
683 * Incomplete header ?
684 * Only checks for the IP header, there should be an
685 * additional check for longer headers in upper levels.
688 if (!pskb_may_pull(skb
, sizeof(struct iphdr
)))
691 icmph
= icmp_hdr(skb
);
692 iph
= (struct iphdr
*)skb
->data
;
694 if (iph
->ihl
< 5) /* Mangled header, drop. */
697 if (icmph
->type
== ICMP_DEST_UNREACH
) {
698 switch (icmph
->code
& 15) {
699 case ICMP_NET_UNREACH
:
700 case ICMP_HOST_UNREACH
:
701 case ICMP_PROT_UNREACH
:
702 case ICMP_PORT_UNREACH
:
704 case ICMP_FRAG_NEEDED
:
705 if (ipv4_config
.no_pmtu_disc
) {
706 LIMIT_NETDEBUG(KERN_INFO
"ICMP: %u.%u.%u.%u: "
707 "fragmentation needed "
709 NIPQUAD(iph
->daddr
));
711 info
= ip_rt_frag_needed(net
, iph
,
712 ntohs(icmph
->un
.frag
.mtu
));
718 LIMIT_NETDEBUG(KERN_INFO
"ICMP: %u.%u.%u.%u: Source "
720 NIPQUAD(iph
->daddr
));
725 if (icmph
->code
> NR_ICMP_UNREACH
)
727 } else if (icmph
->type
== ICMP_PARAMETERPROB
)
728 info
= ntohl(icmph
->un
.gateway
) >> 24;
731 * Throw it at our lower layers
733 * RFC 1122: 3.2.2 MUST extract the protocol ID from the passed
735 * RFC 1122: 3.2.2.1 MUST pass ICMP unreach messages to the
737 * RFC 1122: 3.2.2.2 MUST pass ICMP time expired messages to
742 * Check the other end isnt violating RFC 1122. Some routers send
743 * bogus responses to broadcast frames. If you see this message
744 * first check your netmask matches at both ends, if it does then
745 * get the other vendor to fix their kit.
748 if (!sysctl_icmp_ignore_bogus_error_responses
&&
749 inet_addr_type(net
, iph
->daddr
) == RTN_BROADCAST
) {
751 printk(KERN_WARNING
"%u.%u.%u.%u sent an invalid ICMP "
753 "error to a broadcast: %u.%u.%u.%u on %s\n",
754 NIPQUAD(ip_hdr(skb
)->saddr
),
755 icmph
->type
, icmph
->code
,
761 /* Checkin full IP header plus 8 bytes of protocol to
762 * avoid additional coding at protocol handlers.
764 if (!pskb_may_pull(skb
, iph
->ihl
* 4 + 8))
767 iph
= (struct iphdr
*)skb
->data
;
768 protocol
= iph
->protocol
;
771 * Deliver ICMP message to raw sockets. Pretty useless feature?
773 raw_icmp_error(skb
, protocol
, info
);
775 hash
= protocol
& (MAX_INET_PROTOS
- 1);
777 ipprot
= rcu_dereference(inet_protos
[hash
]);
778 if (ipprot
&& ipprot
->err_handler
)
779 ipprot
->err_handler(skb
, info
);
785 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
791 * Handle ICMP_REDIRECT.
794 static void icmp_redirect(struct sk_buff
*skb
)
798 if (skb
->len
< sizeof(struct iphdr
))
802 * Get the copied header of the packet that caused the redirect
804 if (!pskb_may_pull(skb
, sizeof(struct iphdr
)))
807 iph
= (struct iphdr
*)skb
->data
;
809 switch (icmp_hdr(skb
)->code
& 7) {
811 case ICMP_REDIR_NETTOS
:
813 * As per RFC recommendations now handle it as a host redirect.
815 case ICMP_REDIR_HOST
:
816 case ICMP_REDIR_HOSTTOS
:
817 ip_rt_redirect(ip_hdr(skb
)->saddr
, iph
->daddr
,
818 icmp_hdr(skb
)->un
.gateway
,
819 iph
->saddr
, skb
->dev
);
825 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
830 * Handle ICMP_ECHO ("ping") requests.
832 * RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo
834 * RFC 1122: 3.2.2.6 Data received in the ICMP_ECHO request MUST be
835 * included in the reply.
836 * RFC 1812: 4.3.3.6 SHOULD have a config option for silently ignoring
837 * echo requests, MUST have default=NOT.
838 * See also WRT handling of options once they are done and working.
841 static void icmp_echo(struct sk_buff
*skb
)
843 if (!sysctl_icmp_echo_ignore_all
) {
844 struct icmp_bxm icmp_param
;
846 icmp_param
.data
.icmph
= *icmp_hdr(skb
);
847 icmp_param
.data
.icmph
.type
= ICMP_ECHOREPLY
;
848 icmp_param
.skb
= skb
;
849 icmp_param
.offset
= 0;
850 icmp_param
.data_len
= skb
->len
;
851 icmp_param
.head_len
= sizeof(struct icmphdr
);
852 icmp_reply(&icmp_param
, skb
);
857 * Handle ICMP Timestamp requests.
858 * RFC 1122: 3.2.2.8 MAY implement ICMP timestamp requests.
859 * SHOULD be in the kernel for minimum random latency.
860 * MUST be accurate to a few minutes.
861 * MUST be updated at least at 15Hz.
863 static void icmp_timestamp(struct sk_buff
*skb
)
866 struct icmp_bxm icmp_param
;
874 * Fill in the current time as ms since midnight UT:
876 do_gettimeofday(&tv
);
877 icmp_param
.data
.times
[1] = htonl((tv
.tv_sec
% 86400) * 1000 +
879 icmp_param
.data
.times
[2] = icmp_param
.data
.times
[1];
880 if (skb_copy_bits(skb
, 0, &icmp_param
.data
.times
[0], 4))
882 icmp_param
.data
.icmph
= *icmp_hdr(skb
);
883 icmp_param
.data
.icmph
.type
= ICMP_TIMESTAMPREPLY
;
884 icmp_param
.data
.icmph
.code
= 0;
885 icmp_param
.skb
= skb
;
886 icmp_param
.offset
= 0;
887 icmp_param
.data_len
= 0;
888 icmp_param
.head_len
= sizeof(struct icmphdr
) + 12;
889 icmp_reply(&icmp_param
, skb
);
893 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
899 * Handle ICMP_ADDRESS_MASK requests. (RFC950)
901 * RFC1122 (3.2.2.9). A host MUST only send replies to
902 * ADDRESS_MASK requests if it's been configured as an address mask
903 * agent. Receiving a request doesn't constitute implicit permission to
904 * act as one. Of course, implementing this correctly requires (SHOULD)
905 * a way to turn the functionality on and off. Another one for sysctl(),
908 * RFC1812 (4.3.3.9). A router MUST implement it.
909 * A router SHOULD have switch turning it on/off.
910 * This switch MUST be ON by default.
912 * Gratuitous replies, zero-source replies are not implemented,
913 * that complies with RFC. DO NOT implement them!!! All the idea
914 * of broadcast addrmask replies as specified in RFC950 is broken.
915 * The problem is that it is not uncommon to have several prefixes
916 * on one physical interface. Moreover, addrmask agent can even be
917 * not aware of existing another prefixes.
918 * If source is zero, addrmask agent cannot choose correct prefix.
919 * Gratuitous mask announcements suffer from the same problem.
920 * RFC1812 explains it, but still allows to use ADDRMASK,
921 * that is pretty silly. --ANK
923 * All these rules are so bizarre, that I removed kernel addrmask
924 * support at all. It is wrong, it is obsolete, nobody uses it in
927 * Furthermore you can do it with a usermode address agent program
931 static void icmp_address(struct sk_buff
*skb
)
935 printk(KERN_DEBUG
"a guy asks for address mask. Who is it?\n");
940 * RFC1812 (4.3.3.9). A router SHOULD listen all replies, and complain
941 * loudly if an inconsistency is found.
944 static void icmp_address_reply(struct sk_buff
*skb
)
946 struct rtable
*rt
= skb
->rtable
;
947 struct net_device
*dev
= skb
->dev
;
948 struct in_device
*in_dev
;
949 struct in_ifaddr
*ifa
;
951 if (skb
->len
< 4 || !(rt
->rt_flags
&RTCF_DIRECTSRC
))
954 in_dev
= in_dev_get(dev
);
958 if (in_dev
->ifa_list
&&
959 IN_DEV_LOG_MARTIANS(in_dev
) &&
960 IN_DEV_FORWARD(in_dev
)) {
963 mp
= skb_header_pointer(skb
, 0, sizeof(_mask
), &_mask
);
965 for (ifa
= in_dev
->ifa_list
; ifa
; ifa
= ifa
->ifa_next
) {
966 if (*mp
== ifa
->ifa_mask
&&
967 inet_ifa_match(rt
->rt_src
, ifa
))
970 if (!ifa
&& net_ratelimit()) {
971 printk(KERN_INFO
"Wrong address mask %u.%u.%u.%u from "
973 NIPQUAD(*mp
), dev
->name
, NIPQUAD(rt
->rt_src
));
981 static void icmp_discard(struct sk_buff
*skb
)
986 * Deal with incoming ICMP packets.
988 int icmp_rcv(struct sk_buff
*skb
)
990 struct icmphdr
*icmph
;
991 struct rtable
*rt
= skb
->rtable
;
993 if (!xfrm4_policy_check(NULL
, XFRM_POLICY_IN
, skb
)) {
996 if (!(skb
->sp
&& skb
->sp
->xvec
[skb
->sp
->len
- 1]->props
.flags
&
1000 if (!pskb_may_pull(skb
, sizeof(*icmph
) + sizeof(struct iphdr
)))
1003 nh
= skb_network_offset(skb
);
1004 skb_set_network_header(skb
, sizeof(*icmph
));
1006 if (!xfrm4_policy_check_reverse(NULL
, XFRM_POLICY_IN
, skb
))
1009 skb_set_network_header(skb
, nh
);
1012 ICMP_INC_STATS_BH(ICMP_MIB_INMSGS
);
1014 switch (skb
->ip_summed
) {
1015 case CHECKSUM_COMPLETE
:
1016 if (!csum_fold(skb
->csum
))
1021 if (__skb_checksum_complete(skb
))
1025 if (!pskb_pull(skb
, sizeof(*icmph
)))
1028 icmph
= icmp_hdr(skb
);
1030 ICMPMSGIN_INC_STATS_BH(icmph
->type
);
1032 * 18 is the highest 'known' ICMP type. Anything else is a mystery
1034 * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
1037 if (icmph
->type
> NR_ICMP_TYPES
)
1042 * Parse the ICMP message
1045 if (rt
->rt_flags
& (RTCF_BROADCAST
| RTCF_MULTICAST
)) {
1047 * RFC 1122: 3.2.2.6 An ICMP_ECHO to broadcast MAY be
1048 * silently ignored (we let user decide with a sysctl).
1049 * RFC 1122: 3.2.2.8 An ICMP_TIMESTAMP MAY be silently
1050 * discarded if to broadcast/multicast.
1052 if ((icmph
->type
== ICMP_ECHO
||
1053 icmph
->type
== ICMP_TIMESTAMP
) &&
1054 sysctl_icmp_echo_ignore_broadcasts
) {
1057 if (icmph
->type
!= ICMP_ECHO
&&
1058 icmph
->type
!= ICMP_TIMESTAMP
&&
1059 icmph
->type
!= ICMP_ADDRESS
&&
1060 icmph
->type
!= ICMP_ADDRESSREPLY
) {
1065 icmp_pointers
[icmph
->type
].handler(skb
);
1071 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
1076 * This table is the definition of how we handle ICMP.
1078 static const struct icmp_control icmp_pointers
[NR_ICMP_TYPES
+ 1] = {
1079 [ICMP_ECHOREPLY
] = {
1080 .handler
= icmp_discard
,
1083 .handler
= icmp_discard
,
1087 .handler
= icmp_discard
,
1090 [ICMP_DEST_UNREACH
] = {
1091 .handler
= icmp_unreach
,
1094 [ICMP_SOURCE_QUENCH
] = {
1095 .handler
= icmp_unreach
,
1099 .handler
= icmp_redirect
,
1103 .handler
= icmp_discard
,
1107 .handler
= icmp_discard
,
1111 .handler
= icmp_echo
,
1114 .handler
= icmp_discard
,
1118 .handler
= icmp_discard
,
1121 [ICMP_TIME_EXCEEDED
] = {
1122 .handler
= icmp_unreach
,
1125 [ICMP_PARAMETERPROB
] = {
1126 .handler
= icmp_unreach
,
1129 [ICMP_TIMESTAMP
] = {
1130 .handler
= icmp_timestamp
,
1132 [ICMP_TIMESTAMPREPLY
] = {
1133 .handler
= icmp_discard
,
1135 [ICMP_INFO_REQUEST
] = {
1136 .handler
= icmp_discard
,
1138 [ICMP_INFO_REPLY
] = {
1139 .handler
= icmp_discard
,
1142 .handler
= icmp_address
,
1144 [ICMP_ADDRESSREPLY
] = {
1145 .handler
= icmp_address_reply
,
1149 static void __net_exit
icmp_sk_exit(struct net
*net
)
1153 for_each_possible_cpu(i
)
1154 sk_release_kernel(net
->ipv4
.icmp_sk
[i
]);
1155 kfree(net
->ipv4
.icmp_sk
);
1156 net
->ipv4
.icmp_sk
= NULL
;
1159 int __net_init
icmp_sk_init(struct net
*net
)
1164 kzalloc(nr_cpu_ids
* sizeof(struct sock
*), GFP_KERNEL
);
1165 if (net
->ipv4
.icmp_sk
== NULL
)
1168 for_each_possible_cpu(i
) {
1170 struct socket
*sock
;
1171 struct inet_sock
*inet
;
1173 err
= sock_create_kern(PF_INET
, SOCK_RAW
, IPPROTO_ICMP
, &sock
);
1177 net
->ipv4
.icmp_sk
[i
] = sk
= sock
->sk
;
1178 sk_change_net(sk
, net
);
1180 sk
->sk_allocation
= GFP_ATOMIC
;
1182 /* Enough space for 2 64K ICMP packets, including
1183 * sk_buff struct overhead.
1186 (2 * ((64 * 1024) + sizeof(struct sk_buff
)));
1190 inet
->pmtudisc
= IP_PMTUDISC_DONT
;
1192 /* Unhash it so that IP input processing does not even
1193 * see it, we do not wish this socket to see incoming
1196 sk
->sk_prot
->unhash(sk
);
1201 for_each_possible_cpu(i
)
1202 sk_release_kernel(net
->ipv4
.icmp_sk
[i
]);
1203 kfree(net
->ipv4
.icmp_sk
);
1207 static struct pernet_operations __net_initdata icmp_sk_ops
= {
1208 .init
= icmp_sk_init
,
1209 .exit
= icmp_sk_exit
,
1212 int __init
icmp_init(void)
1214 return register_pernet_device(&icmp_sk_ops
);
1217 EXPORT_SYMBOL(icmp_err_convert
);
1218 EXPORT_SYMBOL(icmp_send
);
1219 EXPORT_SYMBOL(icmp_statistics
);
1220 EXPORT_SYMBOL(xrlim_allow
);