2 * NET3: Implementation of the ICMP protocol layer.
4 * Alan Cox, <alan@lxorguk.ukuu.org.uk>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
11 * Some of the function names and the icmp unreach table for this
12 * module were derived from [icmp.c 1.0.11 06/02/93] by
13 * Ross Biro, Fred N. van Kempen, Mark Evans, Alan Cox, Gerhard Koerting.
14 * Other than that this module is a complete rewrite.
17 * Clemens Fruhwirth : introduce global icmp rate limiting
18 * with icmp type masking ability instead
19 * of broken per type icmp timeouts.
20 * Mike Shaver : RFC1122 checks.
21 * Alan Cox : Multicast ping reply as self.
22 * Alan Cox : Fix atomicity lockup in ip_build_xmit
24 * Alan Cox : Added 216,128 byte paths to the MTU
26 * Martin Mares : RFC1812 checks.
27 * Martin Mares : Can be configured to follow redirects
28 * if acting as a router _without_ a
29 * routing protocol (RFC 1812).
30 * Martin Mares : Echo requests may be configured to
31 * be ignored (RFC 1812).
32 * Martin Mares : Limitation of ICMP error message
33 * transmit rate (RFC 1812).
34 * Martin Mares : TOS and Precedence set correctly
36 * Martin Mares : Now copying as much data from the
37 * original packet as we can without
38 * exceeding 576 bytes (RFC 1812).
39 * Willy Konynenberg : Transparent proxying support.
40 * Keith Owens : RFC1191 correction for 4.2BSD based
42 * Thomas Quinot : ICMP Dest Unreach codes up to 15 are
44 * Andi Kleen : Check all packet lengths properly
45 * and moved all kfree_skb() up to
47 * Andi Kleen : Move the rate limit bookkeeping
48 * into the dest entry and use a token
49 * bucket filter (thanks to ANK). Make
50 * the rates sysctl configurable.
51 * Yu Tianli : Fixed two ugly bugs in icmp_send
52 * - IP option length was accounted wrongly
53 * - ICMP header length was not accounted
55 * Tristan Greaves : Added sysctl option to ignore bogus
56 * broadcast responses from broken routers.
60 * - Should use skb_pull() instead of all the manual checking.
61 * This would also greatly simply some upper layer error handlers. --AK
65 #include <linux/module.h>
66 #include <linux/types.h>
67 #include <linux/jiffies.h>
68 #include <linux/kernel.h>
69 #include <linux/fcntl.h>
70 #include <linux/socket.h>
72 #include <linux/inet.h>
73 #include <linux/inetdevice.h>
74 #include <linux/netdevice.h>
75 #include <linux/string.h>
76 #include <linux/netfilter_ipv4.h>
79 #include <net/route.h>
80 #include <net/protocol.h>
85 #include <linux/skbuff.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>
94 #include <net/inet_common.h>
97 * Build xmit assembly blocks
106 struct icmphdr icmph
;
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 */
123 .errno
= EHOSTUNREACH
, /* ICMP_HOST_UNREACH */
127 .errno
= ENOPROTOOPT
/* ICMP_PROT_UNREACH */,
131 .errno
= ECONNREFUSED
, /* ICMP_PORT_UNREACH */
135 .errno
= EMSGSIZE
, /* ICMP_FRAG_NEEDED */
139 .errno
= EOPNOTSUPP
, /* ICMP_SR_FAILED */
143 .errno
= ENETUNREACH
, /* ICMP_NET_UNKNOWN */
147 .errno
= EHOSTDOWN
, /* ICMP_HOST_UNKNOWN */
151 .errno
= ENONET
, /* ICMP_HOST_ISOLATED */
155 .errno
= ENETUNREACH
, /* ICMP_NET_ANO */
159 .errno
= EHOSTUNREACH
, /* ICMP_HOST_ANO */
163 .errno
= ENETUNREACH
, /* ICMP_NET_UNR_TOS */
167 .errno
= EHOSTUNREACH
, /* ICMP_HOST_UNR_TOS */
171 .errno
= EHOSTUNREACH
, /* ICMP_PKT_FILTERED */
175 .errno
= EHOSTUNREACH
, /* ICMP_PREC_VIOLATION */
179 .errno
= EHOSTUNREACH
, /* ICMP_PREC_CUTOFF */
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
)
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.
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
;
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
) {
266 dst
->rate_tokens
= token
;
270 static inline int icmpv4_xrlim_allow(struct net
*net
, struct rtable
*rt
,
273 struct dst_entry
*dst
= &rt
->u
.dst
;
276 if (type
> NR_ICMP_TYPES
)
279 /* Don't limit PMTU discovery. */
280 if (type
== ICMP_DEST_UNREACH
&& code
== ICMP_FRAG_NEEDED
)
283 /* No rate limit on loopback */
284 if (dst
->dev
&& (dst
->dev
->flags
&IFF_LOOPBACK
))
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
);
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
307 static int icmp_glue_bits(void *from
, char *to
, int offset
, int len
, int odd
,
310 struct icmp_bxm
*icmp_param
= (struct icmp_bxm
*)from
;
313 csum
= skb_copy_and_csum_bits(icmp_param
->skb
,
314 icmp_param
->offset
+ offset
,
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
);
323 static void icmp_push_reply(struct icmp_bxm
*icmp_param
,
324 struct ipcm_cookie
*ipc
, struct rtable
**rt
)
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
);
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
,
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
);
362 struct inet_sock
*inet
;
365 if (ip_options_echo(&icmp_param
->replyopts
, skb
))
368 sk
= icmp_xmit_lock(net
);
373 icmp_param
->data
.icmph
.checksum
= 0;
375 inet
->tos
= ip_hdr(skb
)->tos
;
376 daddr
= ipc
.addr
= rt
->rt_src
;
379 if (icmp_param
->replyopts
.optlen
) {
380 ipc
.opt
= &icmp_param
->replyopts
;
382 daddr
= icmp_param
->replyopts
.faddr
;
385 struct flowi fl
= { .nl_u
= { .ip4_u
=
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
))
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
);
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
)
418 struct icmp_bxm icmp_param
;
419 struct rtable
*rt
= skb_rtable(skb_in
);
420 struct ipcm_cookie ipc
;
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
435 iph
= ip_hdr(skb_in
);
437 if ((u8
*)iph
< skb_in
->head
||
438 (skb_in
->network_header
+ sizeof(*iph
)) > skb_in
->tail
)
442 * No replies to physical multicast/broadcast
444 if (skb_in
->pkt_type
!= PACKET_HOST
)
448 * Now check at the protocol level
450 if (rt
->rt_flags
& (RTCF_BROADCAST
| RTCF_MULTICAST
))
454 * Only reply to fragment 0. We byte re-order the constant
455 * mask for efficiency.
457 if (iph
->frag_off
& htons(IP_OFFSET
))
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
468 if (iph
->protocol
== IPPROTO_ICMP
) {
469 u8 _inner_type
, *itp
;
471 itp
= skb_header_pointer(skb_in
,
472 skb_network_header(skb_in
) +
474 offsetof(struct icmphdr
,
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
)
492 sk
= icmp_xmit_lock(net
);
497 * Construct source address and options.
501 if (!(rt
->rt_flags
& RTCF_LOCAL
)) {
502 struct net_device
*dev
= NULL
;
505 net
->ipv4
.sysctl_icmp_errors_use_inbound_ifaddr
)
506 dev
= dev_get_by_index(net
, rt
->fl
.iif
);
509 saddr
= inet_select_addr(dev
, 0, RT_SCOPE_LINK
);
515 tos
= icmp_pointers
[type
].error
? ((iph
->tos
& IPTOS_TOS_MASK
) |
516 IPTOS_PREC_INTERNETCONTROL
) :
519 if (ip_options_echo(&icmp_param
.replyopts
, skb_in
))
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
;
542 .daddr
= icmp_param
.replyopts
.srr
?
543 icmp_param
.replyopts
.faddr
:
549 .proto
= IPPROTO_ICMP
,
560 security_skb_classify_flow(skb_in
, &fl
);
561 if (__ip_route_output_key(net
, &rt
, &fl
))
564 /* No need to clone since we're just using its address. */
567 err
= xfrm_lookup(net
, (struct dst_entry
**)&rt
, &fl
, NULL
, 0);
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
);
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
;
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
);
604 goto relookup_failed
;
606 err
= xfrm_lookup(net
, (struct dst_entry
**)&rt2
, &fl
, NULL
,
610 dst_release(&rt
->u
.dst
);
624 if (!icmpv4_xrlim_allow(net
, rt
, type
, code
))
627 /* RFC says return as much as we can without exceeding 576 bytes. */
629 room
= dst_mtu(&rt
->u
.dst
);
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
);
644 icmp_xmit_unlock(sk
);
650 * Handle ICMP_DEST_UNREACH, ICMP_TIME_EXCEED, and ICMP_QUENCH.
653 static void icmp_unreach(struct sk_buff
*skb
)
656 struct icmphdr
*icmph
;
658 struct net_protocol
*ipprot
;
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
)))
673 icmph
= icmp_hdr(skb
);
674 iph
= (struct iphdr
*)skb
->data
;
676 if (iph
->ihl
< 5) /* Mangled header, drop. */
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
:
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",
691 info
= ip_rt_frag_needed(net
, iph
,
692 ntohs(icmph
->un
.frag
.mtu
),
699 LIMIT_NETDEBUG(KERN_INFO
"ICMP: %pI4: Source Route Failed.\n",
705 if (icmph
->code
> NR_ICMP_UNREACH
)
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
715 * RFC 1122: 3.2.2.1 MUST pass ICMP unreach messages to the
717 * RFC 1122: 3.2.2.2 MUST pass ICMP time expired messages to
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
) {
731 printk(KERN_WARNING
"%pI4 sent an invalid ICMP "
733 "error to a broadcast: %pI4 on %s\n",
735 icmph
->type
, icmph
->code
,
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))
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);
757 ipprot
= rcu_dereference(inet_protos
[hash
]);
758 if (ipprot
&& ipprot
->err_handler
)
759 ipprot
->err_handler(skb
, info
);
765 ICMP_INC_STATS_BH(net
, ICMP_MIB_INERRORS
);
771 * Handle ICMP_REDIRECT.
774 static void icmp_redirect(struct sk_buff
*skb
)
778 if (skb
->len
< sizeof(struct iphdr
))
782 * Get the copied header of the packet that caused the redirect
784 if (!pskb_may_pull(skb
, sizeof(struct iphdr
)))
787 iph
= (struct iphdr
*)skb
->data
;
789 switch (icmp_hdr(skb
)->code
& 7) {
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
);
805 ICMP_INC_STATS_BH(dev_net(skb
->dev
), ICMP_MIB_INERRORS
);
810 * Handle ICMP_ECHO ("ping") requests.
812 * RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo
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
)
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
)
849 struct icmp_bxm icmp_param
;
857 * Fill in the current time as ms since midnight UT:
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))
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
);
876 ICMP_INC_STATS_BH(dev_net(skb_dst(skb
)->dev
), ICMP_MIB_INERRORS
);
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(),
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
910 * Furthermore you can do it with a usermode address agent program
914 static void icmp_address(struct sk_buff
*skb
)
918 printk(KERN_DEBUG
"a guy asks for address mask. Who is it?\n");
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
))
937 in_dev
= in_dev_get(dev
);
941 if (in_dev
->ifa_list
&&
942 IN_DEV_LOG_MARTIANS(in_dev
) &&
943 IN_DEV_FORWARD(in_dev
)) {
946 mp
= skb_header_pointer(skb
, 0, sizeof(_mask
), &_mask
);
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
))
953 if (!ifa
&& net_ratelimit()) {
954 printk(KERN_INFO
"Wrong address mask %pI4 from %s/%pI4\n",
955 mp
, dev
->name
, &rt
->rt_src
);
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
);
980 if (!(sp
&& sp
->xvec
[sp
->len
- 1]->props
.flags
&
984 if (!pskb_may_pull(skb
, sizeof(*icmph
) + sizeof(struct iphdr
)))
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
))
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
))
1005 if (__skb_checksum_complete(skb
))
1009 if (!pskb_pull(skb
, sizeof(*icmph
)))
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
1021 if (icmph
->type
> NR_ICMP_TYPES
)
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
) {
1041 if (icmph
->type
!= ICMP_ECHO
&&
1042 icmph
->type
!= ICMP_TIMESTAMP
&&
1043 icmph
->type
!= ICMP_ADDRESS
&&
1044 icmph
->type
!= ICMP_ADDRESSREPLY
) {
1049 icmp_pointers
[icmph
->type
].handler(skb
);
1055 ICMP_INC_STATS_BH(net
, ICMP_MIB_INERRORS
);
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
,
1067 .handler
= icmp_discard
,
1071 .handler
= icmp_discard
,
1074 [ICMP_DEST_UNREACH
] = {
1075 .handler
= icmp_unreach
,
1078 [ICMP_SOURCE_QUENCH
] = {
1079 .handler
= icmp_unreach
,
1083 .handler
= icmp_redirect
,
1087 .handler
= icmp_discard
,
1091 .handler
= icmp_discard
,
1095 .handler
= icmp_echo
,
1098 .handler
= icmp_discard
,
1102 .handler
= icmp_discard
,
1105 [ICMP_TIME_EXCEEDED
] = {
1106 .handler
= icmp_unreach
,
1109 [ICMP_PARAMETERPROB
] = {
1110 .handler
= icmp_unreach
,
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
,
1126 .handler
= icmp_address
,
1128 [ICMP_ADDRESSREPLY
] = {
1129 .handler
= icmp_address_reply
,
1133 static void __net_exit
icmp_sk_exit(struct net
*net
)
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
)
1148 kzalloc(nr_cpu_ids
* sizeof(struct sock
*), GFP_KERNEL
);
1149 if (net
->ipv4
.icmp_sk
== NULL
)
1152 for_each_possible_cpu(i
) {
1155 err
= inet_ctl_sock_create(&sk
, PF_INET
,
1156 SOCK_RAW
, IPPROTO_ICMP
, net
);
1160 net
->ipv4
.icmp_sk
[i
] = sk
;
1162 /* Enough space for 2 64K ICMP packets, including
1163 * sk_buff struct overhead.
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.
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;
1197 for_each_possible_cpu(i
)
1198 inet_ctl_sock_destroy(net
->ipv4
.icmp_sk
[i
]);
1199 kfree(net
->ipv4
.icmp_sk
);
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
);