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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
79 #include <linux/slab.h>
82 #include <net/route.h>
83 #include <net/protocol.h>
89 #include <linux/skbuff.h>
91 #include <linux/errno.h>
92 #include <linux/timer.h>
93 #include <linux/init.h>
94 #include <asm/uaccess.h>
95 #include <net/checksum.h>
97 #include <net/inet_common.h>
98 #include <net/ip_fib.h>
101 * Build xmit assembly blocks
110 struct icmphdr icmph
;
114 struct ip_options_data replyopts
;
117 /* An array of errno for error messages from dest unreach. */
118 /* RFC 1122: 3.2.2.1 States that NET_UNREACH, HOST_UNREACH and SR_FAILED MUST be considered 'transient errs'. */
120 const struct icmp_err icmp_err_convert
[] = {
122 .errno
= ENETUNREACH
, /* ICMP_NET_UNREACH */
126 .errno
= EHOSTUNREACH
, /* ICMP_HOST_UNREACH */
130 .errno
= ENOPROTOOPT
/* ICMP_PROT_UNREACH */,
134 .errno
= ECONNREFUSED
, /* ICMP_PORT_UNREACH */
138 .errno
= EMSGSIZE
, /* ICMP_FRAG_NEEDED */
142 .errno
= EOPNOTSUPP
, /* ICMP_SR_FAILED */
146 .errno
= ENETUNREACH
, /* ICMP_NET_UNKNOWN */
150 .errno
= EHOSTDOWN
, /* ICMP_HOST_UNKNOWN */
154 .errno
= ENONET
, /* ICMP_HOST_ISOLATED */
158 .errno
= ENETUNREACH
, /* ICMP_NET_ANO */
162 .errno
= EHOSTUNREACH
, /* ICMP_HOST_ANO */
166 .errno
= ENETUNREACH
, /* ICMP_NET_UNR_TOS */
170 .errno
= EHOSTUNREACH
, /* ICMP_HOST_UNR_TOS */
174 .errno
= EHOSTUNREACH
, /* ICMP_PKT_FILTERED */
178 .errno
= EHOSTUNREACH
, /* ICMP_PREC_VIOLATION */
182 .errno
= EHOSTUNREACH
, /* ICMP_PREC_CUTOFF */
186 EXPORT_SYMBOL(icmp_err_convert
);
189 * ICMP control array. This specifies what to do with each ICMP.
192 struct icmp_control
{
193 void (*handler
)(struct sk_buff
*skb
);
194 short error
; /* This ICMP is classed as an error message */
197 static const struct icmp_control icmp_pointers
[NR_ICMP_TYPES
+1];
200 * The ICMP socket(s). This is the most convenient way to flow control
201 * our ICMP output as well as maintain a clean interface throughout
202 * all layers. All Socketless IP sends will soon be gone.
204 * On SMP we have one ICMP socket per-cpu.
206 static struct sock
*icmp_sk(struct net
*net
)
208 return net
->ipv4
.icmp_sk
[smp_processor_id()];
211 static inline struct sock
*icmp_xmit_lock(struct net
*net
)
219 if (unlikely(!spin_trylock(&sk
->sk_lock
.slock
))) {
220 /* This can happen if the output path signals a
221 * dst_link_failure() for an outgoing ICMP packet.
229 static inline void icmp_xmit_unlock(struct sock
*sk
)
231 spin_unlock_bh(&sk
->sk_lock
.slock
);
235 * Send an ICMP frame.
238 static inline bool icmpv4_xrlim_allow(struct net
*net
, struct rtable
*rt
,
239 struct flowi4
*fl4
, int type
, int code
)
241 struct dst_entry
*dst
= &rt
->dst
;
244 if (type
> NR_ICMP_TYPES
)
247 /* Don't limit PMTU discovery. */
248 if (type
== ICMP_DEST_UNREACH
&& code
== ICMP_FRAG_NEEDED
)
251 /* No rate limit on loopback */
252 if (dst
->dev
&& (dst
->dev
->flags
&IFF_LOOPBACK
))
255 /* Limit if icmp type is enabled in ratemask. */
256 if ((1 << type
) & net
->ipv4
.sysctl_icmp_ratemask
) {
257 struct inet_peer
*peer
= rt_get_peer_create(rt
, fl4
->daddr
);
258 rc
= inet_peer_xrlim_allow(peer
,
259 net
->ipv4
.sysctl_icmp_ratelimit
);
266 * Maintain the counters used in the SNMP statistics for outgoing ICMP
268 void icmp_out_count(struct net
*net
, unsigned char type
)
270 ICMPMSGOUT_INC_STATS(net
, type
);
271 ICMP_INC_STATS(net
, ICMP_MIB_OUTMSGS
);
275 * Checksum each fragment, and on the first include the headers and final
278 static int icmp_glue_bits(void *from
, char *to
, int offset
, int len
, int odd
,
281 struct icmp_bxm
*icmp_param
= (struct icmp_bxm
*)from
;
284 csum
= skb_copy_and_csum_bits(icmp_param
->skb
,
285 icmp_param
->offset
+ offset
,
288 skb
->csum
= csum_block_add(skb
->csum
, csum
, odd
);
289 if (icmp_pointers
[icmp_param
->data
.icmph
.type
].error
)
290 nf_ct_attach(skb
, icmp_param
->skb
);
294 static void icmp_push_reply(struct icmp_bxm
*icmp_param
,
296 struct ipcm_cookie
*ipc
, struct rtable
**rt
)
301 sk
= icmp_sk(dev_net((*rt
)->dst
.dev
));
302 if (ip_append_data(sk
, fl4
, icmp_glue_bits
, icmp_param
,
303 icmp_param
->data_len
+icmp_param
->head_len
,
304 icmp_param
->head_len
,
305 ipc
, rt
, MSG_DONTWAIT
) < 0) {
306 ICMP_INC_STATS_BH(sock_net(sk
), ICMP_MIB_OUTERRORS
);
307 ip_flush_pending_frames(sk
);
308 } else if ((skb
= skb_peek(&sk
->sk_write_queue
)) != NULL
) {
309 struct icmphdr
*icmph
= icmp_hdr(skb
);
311 struct sk_buff
*skb1
;
313 skb_queue_walk(&sk
->sk_write_queue
, skb1
) {
314 csum
= csum_add(csum
, skb1
->csum
);
316 csum
= csum_partial_copy_nocheck((void *)&icmp_param
->data
,
318 icmp_param
->head_len
, csum
);
319 icmph
->checksum
= csum_fold(csum
);
320 skb
->ip_summed
= CHECKSUM_NONE
;
321 ip_push_pending_frames(sk
, fl4
);
326 * Driving logic for building and sending ICMP messages.
329 static void icmp_reply(struct icmp_bxm
*icmp_param
, struct sk_buff
*skb
)
331 struct ipcm_cookie ipc
;
332 struct rtable
*rt
= skb_rtable(skb
);
333 struct net
*net
= dev_net(rt
->dst
.dev
);
336 struct inet_sock
*inet
;
339 if (ip_options_echo(&icmp_param
->replyopts
.opt
.opt
, skb
))
342 sk
= icmp_xmit_lock(net
);
347 icmp_param
->data
.icmph
.checksum
= 0;
349 inet
->tos
= ip_hdr(skb
)->tos
;
350 daddr
= ipc
.addr
= ip_hdr(skb
)->saddr
;
351 saddr
= fib_compute_spec_dst(skb
);
354 if (icmp_param
->replyopts
.opt
.opt
.optlen
) {
355 ipc
.opt
= &icmp_param
->replyopts
.opt
;
356 if (ipc
.opt
->opt
.srr
)
357 daddr
= icmp_param
->replyopts
.opt
.opt
.faddr
;
359 memset(&fl4
, 0, sizeof(fl4
));
362 fl4
.flowi4_tos
= RT_TOS(ip_hdr(skb
)->tos
);
363 fl4
.flowi4_proto
= IPPROTO_ICMP
;
364 security_skb_classify_flow(skb
, flowi4_to_flowi(&fl4
));
365 rt
= ip_route_output_key(net
, &fl4
);
368 if (icmpv4_xrlim_allow(net
, rt
, &fl4
, icmp_param
->data
.icmph
.type
,
369 icmp_param
->data
.icmph
.code
))
370 icmp_push_reply(icmp_param
, &fl4
, &ipc
, &rt
);
373 icmp_xmit_unlock(sk
);
376 static struct rtable
*icmp_route_lookup(struct net
*net
,
378 struct sk_buff
*skb_in
,
379 const struct iphdr
*iph
,
380 __be32 saddr
, u8 tos
,
382 struct icmp_bxm
*param
)
384 struct rtable
*rt
, *rt2
;
385 struct flowi4 fl4_dec
;
388 memset(fl4
, 0, sizeof(*fl4
));
389 fl4
->daddr
= (param
->replyopts
.opt
.opt
.srr
?
390 param
->replyopts
.opt
.opt
.faddr
: iph
->saddr
);
392 fl4
->flowi4_tos
= RT_TOS(tos
);
393 fl4
->flowi4_proto
= IPPROTO_ICMP
;
394 fl4
->fl4_icmp_type
= type
;
395 fl4
->fl4_icmp_code
= code
;
396 security_skb_classify_flow(skb_in
, flowi4_to_flowi(fl4
));
397 rt
= __ip_route_output_key(net
, fl4
);
401 /* No need to clone since we're just using its address. */
404 rt
= (struct rtable
*) xfrm_lookup(net
, &rt
->dst
,
405 flowi4_to_flowi(fl4
), NULL
, 0);
409 } else if (PTR_ERR(rt
) == -EPERM
) {
414 err
= xfrm_decode_session_reverse(skb_in
, flowi4_to_flowi(&fl4_dec
), AF_INET
);
416 goto relookup_failed
;
418 if (inet_addr_type(net
, fl4_dec
.saddr
) == RTN_LOCAL
) {
419 rt2
= __ip_route_output_key(net
, &fl4_dec
);
423 struct flowi4 fl4_2
= {};
424 unsigned long orefdst
;
426 fl4_2
.daddr
= fl4_dec
.saddr
;
427 rt2
= ip_route_output_key(net
, &fl4_2
);
430 goto relookup_failed
;
433 orefdst
= skb_in
->_skb_refdst
; /* save old refdst */
434 err
= ip_route_input(skb_in
, fl4_dec
.daddr
, fl4_dec
.saddr
,
435 RT_TOS(tos
), rt2
->dst
.dev
);
437 dst_release(&rt2
->dst
);
438 rt2
= skb_rtable(skb_in
);
439 skb_in
->_skb_refdst
= orefdst
; /* restore old refdst */
443 goto relookup_failed
;
445 rt2
= (struct rtable
*) xfrm_lookup(net
, &rt2
->dst
,
446 flowi4_to_flowi(&fl4_dec
), NULL
,
449 dst_release(&rt
->dst
);
450 memcpy(fl4
, &fl4_dec
, sizeof(*fl4
));
452 } else if (PTR_ERR(rt2
) == -EPERM
) {
454 dst_release(&rt
->dst
);
458 goto relookup_failed
;
469 * Send an ICMP message in response to a situation
471 * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header.
472 * MAY send more (we do).
473 * MUST NOT change this header information.
474 * MUST NOT reply to a multicast/broadcast IP address.
475 * MUST NOT reply to a multicast/broadcast MAC address.
476 * MUST reply to only the first fragment.
479 void icmp_send(struct sk_buff
*skb_in
, int type
, int code
, __be32 info
)
483 struct icmp_bxm icmp_param
;
484 struct rtable
*rt
= skb_rtable(skb_in
);
485 struct ipcm_cookie ipc
;
494 net
= dev_net(rt
->dst
.dev
);
497 * Find the original header. It is expected to be valid, of course.
498 * Check this, icmp_send is called from the most obscure devices
501 iph
= ip_hdr(skb_in
);
503 if ((u8
*)iph
< skb_in
->head
||
504 (skb_in
->network_header
+ sizeof(*iph
)) > skb_in
->tail
)
508 * No replies to physical multicast/broadcast
510 if (skb_in
->pkt_type
!= PACKET_HOST
)
514 * Now check at the protocol level
516 if (rt
->rt_flags
& (RTCF_BROADCAST
| RTCF_MULTICAST
))
520 * Only reply to fragment 0. We byte re-order the constant
521 * mask for efficiency.
523 if (iph
->frag_off
& htons(IP_OFFSET
))
527 * If we send an ICMP error to an ICMP error a mess would result..
529 if (icmp_pointers
[type
].error
) {
531 * We are an error, check if we are replying to an
534 if (iph
->protocol
== IPPROTO_ICMP
) {
535 u8 _inner_type
, *itp
;
537 itp
= skb_header_pointer(skb_in
,
538 skb_network_header(skb_in
) +
540 offsetof(struct icmphdr
,
549 * Assume any unknown ICMP type is an error. This
550 * isn't specified by the RFC, but think about it..
552 if (*itp
> NR_ICMP_TYPES
||
553 icmp_pointers
[*itp
].error
)
558 sk
= icmp_xmit_lock(net
);
563 * Construct source address and options.
567 if (!(rt
->rt_flags
& RTCF_LOCAL
)) {
568 struct net_device
*dev
= NULL
;
571 if (rt_is_input_route(rt
) &&
572 net
->ipv4
.sysctl_icmp_errors_use_inbound_ifaddr
)
573 dev
= dev_get_by_index_rcu(net
, rt
->rt_iif
);
576 saddr
= inet_select_addr(dev
, 0, RT_SCOPE_LINK
);
582 tos
= icmp_pointers
[type
].error
? ((iph
->tos
& IPTOS_TOS_MASK
) |
583 IPTOS_PREC_INTERNETCONTROL
) :
586 if (ip_options_echo(&icmp_param
.replyopts
.opt
.opt
, skb_in
))
591 * Prepare data for ICMP header.
594 icmp_param
.data
.icmph
.type
= type
;
595 icmp_param
.data
.icmph
.code
= code
;
596 icmp_param
.data
.icmph
.un
.gateway
= info
;
597 icmp_param
.data
.icmph
.checksum
= 0;
598 icmp_param
.skb
= skb_in
;
599 icmp_param
.offset
= skb_network_offset(skb_in
);
600 inet_sk(sk
)->tos
= tos
;
601 ipc
.addr
= iph
->saddr
;
602 ipc
.opt
= &icmp_param
.replyopts
.opt
;
605 rt
= icmp_route_lookup(net
, &fl4
, skb_in
, iph
, saddr
, tos
,
606 type
, code
, &icmp_param
);
610 if (!icmpv4_xrlim_allow(net
, rt
, &fl4
, type
, code
))
613 /* RFC says return as much as we can without exceeding 576 bytes. */
615 room
= dst_mtu(&rt
->dst
);
618 room
-= sizeof(struct iphdr
) + icmp_param
.replyopts
.opt
.opt
.optlen
;
619 room
-= sizeof(struct icmphdr
);
621 icmp_param
.data_len
= skb_in
->len
- icmp_param
.offset
;
622 if (icmp_param
.data_len
> room
)
623 icmp_param
.data_len
= room
;
624 icmp_param
.head_len
= sizeof(struct icmphdr
);
626 icmp_push_reply(&icmp_param
, &fl4
, &ipc
, &rt
);
630 icmp_xmit_unlock(sk
);
633 EXPORT_SYMBOL(icmp_send
);
637 * Handle ICMP_DEST_UNREACH, ICMP_TIME_EXCEED, and ICMP_QUENCH.
640 static void icmp_unreach(struct sk_buff
*skb
)
642 const struct net_protocol
*ipprot
;
643 const struct iphdr
*iph
;
644 struct icmphdr
*icmph
;
649 net
= dev_net(skb_dst(skb
)->dev
);
652 * Incomplete header ?
653 * Only checks for the IP header, there should be an
654 * additional check for longer headers in upper levels.
657 if (!pskb_may_pull(skb
, sizeof(struct iphdr
)))
660 icmph
= icmp_hdr(skb
);
661 iph
= (const struct iphdr
*)skb
->data
;
663 if (iph
->ihl
< 5) /* Mangled header, drop. */
666 if (icmph
->type
== ICMP_DEST_UNREACH
) {
667 switch (icmph
->code
& 15) {
668 case ICMP_NET_UNREACH
:
669 case ICMP_HOST_UNREACH
:
670 case ICMP_PROT_UNREACH
:
671 case ICMP_PORT_UNREACH
:
673 case ICMP_FRAG_NEEDED
:
674 if (ipv4_config
.no_pmtu_disc
) {
675 LIMIT_NETDEBUG(KERN_INFO
pr_fmt("%pI4: fragmentation needed and DF set\n"),
678 info
= ntohs(icmph
->un
.frag
.mtu
);
684 LIMIT_NETDEBUG(KERN_INFO
pr_fmt("%pI4: Source Route Failed\n"),
690 if (icmph
->code
> NR_ICMP_UNREACH
)
692 } else if (icmph
->type
== ICMP_PARAMETERPROB
)
693 info
= ntohl(icmph
->un
.gateway
) >> 24;
696 * Throw it at our lower layers
698 * RFC 1122: 3.2.2 MUST extract the protocol ID from the passed
700 * RFC 1122: 3.2.2.1 MUST pass ICMP unreach messages to the
702 * RFC 1122: 3.2.2.2 MUST pass ICMP time expired messages to
707 * Check the other end isn't violating RFC 1122. Some routers send
708 * bogus responses to broadcast frames. If you see this message
709 * first check your netmask matches at both ends, if it does then
710 * get the other vendor to fix their kit.
713 if (!net
->ipv4
.sysctl_icmp_ignore_bogus_error_responses
&&
714 inet_addr_type(net
, iph
->daddr
) == RTN_BROADCAST
) {
715 net_warn_ratelimited("%pI4 sent an invalid ICMP type %u, code %u error to a broadcast: %pI4 on %s\n",
717 icmph
->type
, icmph
->code
,
718 &iph
->daddr
, skb
->dev
->name
);
722 /* Checkin full IP header plus 8 bytes of protocol to
723 * avoid additional coding at protocol handlers.
725 if (!pskb_may_pull(skb
, iph
->ihl
* 4 + 8))
728 iph
= (const struct iphdr
*)skb
->data
;
729 protocol
= iph
->protocol
;
732 * Deliver ICMP message to raw sockets. Pretty useless feature?
734 raw_icmp_error(skb
, protocol
, info
);
737 ipprot
= rcu_dereference(inet_protos
[protocol
]);
738 if (ipprot
&& ipprot
->err_handler
)
739 ipprot
->err_handler(skb
, info
);
745 ICMP_INC_STATS_BH(net
, ICMP_MIB_INERRORS
);
751 * Handle ICMP_REDIRECT.
754 static void icmp_redirect(struct sk_buff
*skb
)
756 const struct iphdr
*iph
;
758 if (skb
->len
< sizeof(struct iphdr
))
762 * Get the copied header of the packet that caused the redirect
764 if (!pskb_may_pull(skb
, sizeof(struct iphdr
)))
767 iph
= (const struct iphdr
*)skb
->data
;
769 switch (icmp_hdr(skb
)->code
& 7) {
771 case ICMP_REDIR_NETTOS
:
773 * As per RFC recommendations now handle it as a host redirect.
775 case ICMP_REDIR_HOST
:
776 case ICMP_REDIR_HOSTTOS
:
777 ip_rt_redirect(ip_hdr(skb
)->saddr
, iph
->daddr
,
778 icmp_hdr(skb
)->un
.gateway
,
779 iph
->saddr
, skb
->dev
);
783 /* Ping wants to see redirects.
784 * Let's pretend they are errors of sorts... */
785 if (iph
->protocol
== IPPROTO_ICMP
&&
787 pskb_may_pull(skb
, (iph
->ihl
<<2)+8)) {
788 ping_err(skb
, icmp_hdr(skb
)->un
.gateway
);
794 ICMP_INC_STATS_BH(dev_net(skb
->dev
), ICMP_MIB_INERRORS
);
799 * Handle ICMP_ECHO ("ping") requests.
801 * RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo
803 * RFC 1122: 3.2.2.6 Data received in the ICMP_ECHO request MUST be
804 * included in the reply.
805 * RFC 1812: 4.3.3.6 SHOULD have a config option for silently ignoring
806 * echo requests, MUST have default=NOT.
807 * See also WRT handling of options once they are done and working.
810 static void icmp_echo(struct sk_buff
*skb
)
814 net
= dev_net(skb_dst(skb
)->dev
);
815 if (!net
->ipv4
.sysctl_icmp_echo_ignore_all
) {
816 struct icmp_bxm icmp_param
;
818 icmp_param
.data
.icmph
= *icmp_hdr(skb
);
819 icmp_param
.data
.icmph
.type
= ICMP_ECHOREPLY
;
820 icmp_param
.skb
= skb
;
821 icmp_param
.offset
= 0;
822 icmp_param
.data_len
= skb
->len
;
823 icmp_param
.head_len
= sizeof(struct icmphdr
);
824 icmp_reply(&icmp_param
, skb
);
829 * Handle ICMP Timestamp requests.
830 * RFC 1122: 3.2.2.8 MAY implement ICMP timestamp requests.
831 * SHOULD be in the kernel for minimum random latency.
832 * MUST be accurate to a few minutes.
833 * MUST be updated at least at 15Hz.
835 static void icmp_timestamp(struct sk_buff
*skb
)
838 struct icmp_bxm icmp_param
;
846 * Fill in the current time as ms since midnight UT:
849 icmp_param
.data
.times
[1] = htonl((tv
.tv_sec
% 86400) * MSEC_PER_SEC
+
850 tv
.tv_nsec
/ NSEC_PER_MSEC
);
851 icmp_param
.data
.times
[2] = icmp_param
.data
.times
[1];
852 if (skb_copy_bits(skb
, 0, &icmp_param
.data
.times
[0], 4))
854 icmp_param
.data
.icmph
= *icmp_hdr(skb
);
855 icmp_param
.data
.icmph
.type
= ICMP_TIMESTAMPREPLY
;
856 icmp_param
.data
.icmph
.code
= 0;
857 icmp_param
.skb
= skb
;
858 icmp_param
.offset
= 0;
859 icmp_param
.data_len
= 0;
860 icmp_param
.head_len
= sizeof(struct icmphdr
) + 12;
861 icmp_reply(&icmp_param
, skb
);
865 ICMP_INC_STATS_BH(dev_net(skb_dst(skb
)->dev
), ICMP_MIB_INERRORS
);
871 * Handle ICMP_ADDRESS_MASK requests. (RFC950)
873 * RFC1122 (3.2.2.9). A host MUST only send replies to
874 * ADDRESS_MASK requests if it's been configured as an address mask
875 * agent. Receiving a request doesn't constitute implicit permission to
876 * act as one. Of course, implementing this correctly requires (SHOULD)
877 * a way to turn the functionality on and off. Another one for sysctl(),
880 * RFC1812 (4.3.3.9). A router MUST implement it.
881 * A router SHOULD have switch turning it on/off.
882 * This switch MUST be ON by default.
884 * Gratuitous replies, zero-source replies are not implemented,
885 * that complies with RFC. DO NOT implement them!!! All the idea
886 * of broadcast addrmask replies as specified in RFC950 is broken.
887 * The problem is that it is not uncommon to have several prefixes
888 * on one physical interface. Moreover, addrmask agent can even be
889 * not aware of existing another prefixes.
890 * If source is zero, addrmask agent cannot choose correct prefix.
891 * Gratuitous mask announcements suffer from the same problem.
892 * RFC1812 explains it, but still allows to use ADDRMASK,
893 * that is pretty silly. --ANK
895 * All these rules are so bizarre, that I removed kernel addrmask
896 * support at all. It is wrong, it is obsolete, nobody uses it in
899 * Furthermore you can do it with a usermode address agent program
903 static void icmp_address(struct sk_buff
*skb
)
906 net_dbg_ratelimited("a guy asks for address mask. Who is it?\n");
911 * RFC1812 (4.3.3.9). A router SHOULD listen all replies, and complain
912 * loudly if an inconsistency is found.
913 * called with rcu_read_lock()
916 static void icmp_address_reply(struct sk_buff
*skb
)
918 struct rtable
*rt
= skb_rtable(skb
);
919 struct net_device
*dev
= skb
->dev
;
920 struct in_device
*in_dev
;
921 struct in_ifaddr
*ifa
;
923 if (skb
->len
< 4 || !(rt
->rt_flags
&RTCF_DIRECTSRC
))
926 in_dev
= __in_dev_get_rcu(dev
);
930 if (in_dev
->ifa_list
&&
931 IN_DEV_LOG_MARTIANS(in_dev
) &&
932 IN_DEV_FORWARD(in_dev
)) {
935 mp
= skb_header_pointer(skb
, 0, sizeof(_mask
), &_mask
);
937 for (ifa
= in_dev
->ifa_list
; ifa
; ifa
= ifa
->ifa_next
) {
938 if (*mp
== ifa
->ifa_mask
&&
939 inet_ifa_match(ip_hdr(skb
)->saddr
, ifa
))
943 net_info_ratelimited("Wrong address mask %pI4 from %s/%pI4\n",
945 dev
->name
, &ip_hdr(skb
)->saddr
);
949 static void icmp_discard(struct sk_buff
*skb
)
954 * Deal with incoming ICMP packets.
956 int icmp_rcv(struct sk_buff
*skb
)
958 struct icmphdr
*icmph
;
959 struct rtable
*rt
= skb_rtable(skb
);
960 struct net
*net
= dev_net(rt
->dst
.dev
);
962 if (!xfrm4_policy_check(NULL
, XFRM_POLICY_IN
, skb
)) {
963 struct sec_path
*sp
= skb_sec_path(skb
);
966 if (!(sp
&& sp
->xvec
[sp
->len
- 1]->props
.flags
&
970 if (!pskb_may_pull(skb
, sizeof(*icmph
) + sizeof(struct iphdr
)))
973 nh
= skb_network_offset(skb
);
974 skb_set_network_header(skb
, sizeof(*icmph
));
976 if (!xfrm4_policy_check_reverse(NULL
, XFRM_POLICY_IN
, skb
))
979 skb_set_network_header(skb
, nh
);
982 ICMP_INC_STATS_BH(net
, ICMP_MIB_INMSGS
);
984 switch (skb
->ip_summed
) {
985 case CHECKSUM_COMPLETE
:
986 if (!csum_fold(skb
->csum
))
991 if (__skb_checksum_complete(skb
))
995 if (!pskb_pull(skb
, sizeof(*icmph
)))
998 icmph
= icmp_hdr(skb
);
1000 ICMPMSGIN_INC_STATS_BH(net
, icmph
->type
);
1002 * 18 is the highest 'known' ICMP type. Anything else is a mystery
1004 * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
1007 if (icmph
->type
> NR_ICMP_TYPES
)
1012 * Parse the ICMP message
1015 if (rt
->rt_flags
& (RTCF_BROADCAST
| RTCF_MULTICAST
)) {
1017 * RFC 1122: 3.2.2.6 An ICMP_ECHO to broadcast MAY be
1018 * silently ignored (we let user decide with a sysctl).
1019 * RFC 1122: 3.2.2.8 An ICMP_TIMESTAMP MAY be silently
1020 * discarded if to broadcast/multicast.
1022 if ((icmph
->type
== ICMP_ECHO
||
1023 icmph
->type
== ICMP_TIMESTAMP
) &&
1024 net
->ipv4
.sysctl_icmp_echo_ignore_broadcasts
) {
1027 if (icmph
->type
!= ICMP_ECHO
&&
1028 icmph
->type
!= ICMP_TIMESTAMP
&&
1029 icmph
->type
!= ICMP_ADDRESS
&&
1030 icmph
->type
!= ICMP_ADDRESSREPLY
) {
1035 icmp_pointers
[icmph
->type
].handler(skb
);
1041 ICMP_INC_STATS_BH(net
, ICMP_MIB_INERRORS
);
1046 * This table is the definition of how we handle ICMP.
1048 static const struct icmp_control icmp_pointers
[NR_ICMP_TYPES
+ 1] = {
1049 [ICMP_ECHOREPLY
] = {
1050 .handler
= ping_rcv
,
1053 .handler
= icmp_discard
,
1057 .handler
= icmp_discard
,
1060 [ICMP_DEST_UNREACH
] = {
1061 .handler
= icmp_unreach
,
1064 [ICMP_SOURCE_QUENCH
] = {
1065 .handler
= icmp_unreach
,
1069 .handler
= icmp_redirect
,
1073 .handler
= icmp_discard
,
1077 .handler
= icmp_discard
,
1081 .handler
= icmp_echo
,
1084 .handler
= icmp_discard
,
1088 .handler
= icmp_discard
,
1091 [ICMP_TIME_EXCEEDED
] = {
1092 .handler
= icmp_unreach
,
1095 [ICMP_PARAMETERPROB
] = {
1096 .handler
= icmp_unreach
,
1099 [ICMP_TIMESTAMP
] = {
1100 .handler
= icmp_timestamp
,
1102 [ICMP_TIMESTAMPREPLY
] = {
1103 .handler
= icmp_discard
,
1105 [ICMP_INFO_REQUEST
] = {
1106 .handler
= icmp_discard
,
1108 [ICMP_INFO_REPLY
] = {
1109 .handler
= icmp_discard
,
1112 .handler
= icmp_address
,
1114 [ICMP_ADDRESSREPLY
] = {
1115 .handler
= icmp_address_reply
,
1119 static void __net_exit
icmp_sk_exit(struct net
*net
)
1123 for_each_possible_cpu(i
)
1124 inet_ctl_sock_destroy(net
->ipv4
.icmp_sk
[i
]);
1125 kfree(net
->ipv4
.icmp_sk
);
1126 net
->ipv4
.icmp_sk
= NULL
;
1129 static int __net_init
icmp_sk_init(struct net
*net
)
1134 kzalloc(nr_cpu_ids
* sizeof(struct sock
*), GFP_KERNEL
);
1135 if (net
->ipv4
.icmp_sk
== NULL
)
1138 for_each_possible_cpu(i
) {
1141 err
= inet_ctl_sock_create(&sk
, PF_INET
,
1142 SOCK_RAW
, IPPROTO_ICMP
, net
);
1146 net
->ipv4
.icmp_sk
[i
] = sk
;
1148 /* Enough space for 2 64K ICMP packets, including
1149 * sk_buff/skb_shared_info struct overhead.
1151 sk
->sk_sndbuf
= 2 * SKB_TRUESIZE(64 * 1024);
1154 * Speedup sock_wfree()
1156 sock_set_flag(sk
, SOCK_USE_WRITE_QUEUE
);
1157 inet_sk(sk
)->pmtudisc
= IP_PMTUDISC_DONT
;
1160 /* Control parameters for ECHO replies. */
1161 net
->ipv4
.sysctl_icmp_echo_ignore_all
= 0;
1162 net
->ipv4
.sysctl_icmp_echo_ignore_broadcasts
= 1;
1164 /* Control parameter - ignore bogus broadcast responses? */
1165 net
->ipv4
.sysctl_icmp_ignore_bogus_error_responses
= 1;
1168 * Configurable global rate limit.
1170 * ratelimit defines tokens/packet consumed for dst->rate_token
1171 * bucket ratemask defines which icmp types are ratelimited by
1172 * setting it's bit position.
1175 * dest unreachable (3), source quench (4),
1176 * time exceeded (11), parameter problem (12)
1179 net
->ipv4
.sysctl_icmp_ratelimit
= 1 * HZ
;
1180 net
->ipv4
.sysctl_icmp_ratemask
= 0x1818;
1181 net
->ipv4
.sysctl_icmp_errors_use_inbound_ifaddr
= 0;
1186 for_each_possible_cpu(i
)
1187 inet_ctl_sock_destroy(net
->ipv4
.icmp_sk
[i
]);
1188 kfree(net
->ipv4
.icmp_sk
);
1192 static struct pernet_operations __net_initdata icmp_sk_ops
= {
1193 .init
= icmp_sk_init
,
1194 .exit
= icmp_sk_exit
,
1197 int __init
icmp_init(void)
1199 return register_pernet_subsys(&icmp_sk_ops
);