1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
9 #include <linux/types.h>
10 #include <linux/timer.h>
11 #include <linux/netfilter.h>
13 #include <linux/icmp.h>
14 #include <linux/seq_file.h>
16 #include <net/checksum.h>
17 #include <linux/netfilter_ipv4.h>
18 #include <net/netfilter/nf_conntrack_tuple.h>
19 #include <net/netfilter/nf_conntrack_l4proto.h>
20 #include <net/netfilter/nf_conntrack_core.h>
22 static unsigned long nf_ct_icmp_timeout __read_mostly
= 30*HZ
;
24 static int icmp_pkt_to_tuple(const struct sk_buff
*skb
,
26 struct nf_conntrack_tuple
*tuple
)
28 struct icmphdr _hdr
, *hp
;
30 hp
= skb_header_pointer(skb
, dataoff
, sizeof(_hdr
), &_hdr
);
34 tuple
->dst
.u
.icmp
.type
= hp
->type
;
35 tuple
->src
.u
.icmp
.id
= hp
->un
.echo
.id
;
36 tuple
->dst
.u
.icmp
.code
= hp
->code
;
41 /* Add 1; spaces filled with 0. */
42 static const u_int8_t invmap
[] = {
43 [ICMP_ECHO
] = ICMP_ECHOREPLY
+ 1,
44 [ICMP_ECHOREPLY
] = ICMP_ECHO
+ 1,
45 [ICMP_TIMESTAMP
] = ICMP_TIMESTAMPREPLY
+ 1,
46 [ICMP_TIMESTAMPREPLY
] = ICMP_TIMESTAMP
+ 1,
47 [ICMP_INFO_REQUEST
] = ICMP_INFO_REPLY
+ 1,
48 [ICMP_INFO_REPLY
] = ICMP_INFO_REQUEST
+ 1,
49 [ICMP_ADDRESS
] = ICMP_ADDRESSREPLY
+ 1,
50 [ICMP_ADDRESSREPLY
] = ICMP_ADDRESS
+ 1
53 static int icmp_invert_tuple(struct nf_conntrack_tuple
*tuple
,
54 const struct nf_conntrack_tuple
*orig
)
56 if (orig
->dst
.u
.icmp
.type
>= sizeof(invmap
)
57 || !invmap
[orig
->dst
.u
.icmp
.type
])
60 tuple
->src
.u
.icmp
.id
= orig
->src
.u
.icmp
.id
;
61 tuple
->dst
.u
.icmp
.type
= invmap
[orig
->dst
.u
.icmp
.type
] - 1;
62 tuple
->dst
.u
.icmp
.code
= orig
->dst
.u
.icmp
.code
;
66 /* Print out the per-protocol part of the tuple. */
67 static int icmp_print_tuple(struct seq_file
*s
,
68 const struct nf_conntrack_tuple
*tuple
)
70 return seq_printf(s
, "type=%u code=%u id=%u ",
71 tuple
->dst
.u
.icmp
.type
,
72 tuple
->dst
.u
.icmp
.code
,
73 ntohs(tuple
->src
.u
.icmp
.id
));
76 /* Print out the private part of the conntrack. */
77 static int icmp_print_conntrack(struct seq_file
*s
,
78 const struct nf_conn
*conntrack
)
83 /* Returns verdict for packet, or -1 for invalid. */
84 static int icmp_packet(struct nf_conn
*ct
,
85 const struct sk_buff
*skb
,
87 enum ip_conntrack_info ctinfo
,
91 /* Try to delete connection immediately after all replies:
92 won't actually vanish as we still have skb, and del_timer
93 means this will only run once even if count hits zero twice
94 (theoretically possible with SMP) */
95 if (CTINFO2DIR(ctinfo
) == IP_CT_DIR_REPLY
) {
96 if (atomic_dec_and_test(&ct
->proto
.icmp
.count
)
97 && del_timer(&ct
->timeout
))
98 ct
->timeout
.function((unsigned long)ct
);
100 atomic_inc(&ct
->proto
.icmp
.count
);
101 nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE
, skb
);
102 nf_ct_refresh_acct(ct
, ctinfo
, skb
, nf_ct_icmp_timeout
);
108 /* Called when a new connection for this protocol found. */
109 static int icmp_new(struct nf_conn
*conntrack
,
110 const struct sk_buff
*skb
, unsigned int dataoff
)
112 static const u_int8_t valid_new
[] = {
114 [ICMP_TIMESTAMP
] = 1,
115 [ICMP_INFO_REQUEST
] = 1,
119 if (conntrack
->tuplehash
[0].tuple
.dst
.u
.icmp
.type
>= sizeof(valid_new
)
120 || !valid_new
[conntrack
->tuplehash
[0].tuple
.dst
.u
.icmp
.type
]) {
121 /* Can't create a new ICMP `conn' with this. */
122 pr_debug("icmp: can't create new conn with type %u\n",
123 conntrack
->tuplehash
[0].tuple
.dst
.u
.icmp
.type
);
124 NF_CT_DUMP_TUPLE(&conntrack
->tuplehash
[0].tuple
);
127 atomic_set(&conntrack
->proto
.icmp
.count
, 0);
131 extern struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4
;
132 /* Returns conntrack if it dealt with ICMP, and filled in skb fields */
134 icmp_error_message(struct sk_buff
*skb
,
135 enum ip_conntrack_info
*ctinfo
,
136 unsigned int hooknum
)
138 struct nf_conntrack_tuple innertuple
, origtuple
;
143 struct nf_conntrack_l4proto
*innerproto
;
144 struct nf_conntrack_tuple_hash
*h
;
147 NF_CT_ASSERT(skb
->nfct
== NULL
);
149 /* Not enough header? */
150 inside
= skb_header_pointer(skb
, ip_hdrlen(skb
), sizeof(_in
), &_in
);
154 /* Ignore ICMP's containing fragments (shouldn't happen) */
155 if (inside
->ip
.frag_off
& htons(IP_OFFSET
)) {
156 pr_debug("icmp_error_message: fragment of proto %u\n",
157 inside
->ip
.protocol
);
161 /* rcu_read_lock()ed by nf_hook_slow */
162 innerproto
= __nf_ct_l4proto_find(PF_INET
, inside
->ip
.protocol
);
164 dataoff
= ip_hdrlen(skb
) + sizeof(inside
->icmp
);
165 /* Are they talking about one of our connections? */
166 if (!nf_ct_get_tuple(skb
, dataoff
, dataoff
+ inside
->ip
.ihl
*4, PF_INET
,
167 inside
->ip
.protocol
, &origtuple
,
168 &nf_conntrack_l3proto_ipv4
, innerproto
)) {
169 pr_debug("icmp_error_message: ! get_tuple p=%u",
170 inside
->ip
.protocol
);
174 /* Ordinarily, we'd expect the inverted tupleproto, but it's
175 been preserved inside the ICMP. */
176 if (!nf_ct_invert_tuple(&innertuple
, &origtuple
,
177 &nf_conntrack_l3proto_ipv4
, innerproto
)) {
178 pr_debug("icmp_error_message: no match\n");
182 *ctinfo
= IP_CT_RELATED
;
184 h
= nf_conntrack_find_get(&innertuple
);
186 /* Locally generated ICMPs will match inverted if they
187 haven't been SNAT'ed yet */
188 /* FIXME: NAT code has to handle half-done double NAT --RR */
189 if (hooknum
== NF_IP_LOCAL_OUT
)
190 h
= nf_conntrack_find_get(&origtuple
);
193 pr_debug("icmp_error_message: no match\n");
197 /* Reverse direction from that found */
198 if (NF_CT_DIRECTION(h
) == IP_CT_DIR_REPLY
)
199 *ctinfo
+= IP_CT_IS_REPLY
;
201 if (NF_CT_DIRECTION(h
) == IP_CT_DIR_REPLY
)
202 *ctinfo
+= IP_CT_IS_REPLY
;
205 /* Update skb to refer to this connection */
206 skb
->nfct
= &nf_ct_tuplehash_to_ctrack(h
)->ct_general
;
207 skb
->nfctinfo
= *ctinfo
;
211 /* Small and modified version of icmp_rcv */
213 icmp_error(struct sk_buff
*skb
, unsigned int dataoff
,
214 enum ip_conntrack_info
*ctinfo
, int pf
, unsigned int hooknum
)
216 struct icmphdr _ih
, *icmph
;
218 /* Not enough header? */
219 icmph
= skb_header_pointer(skb
, ip_hdrlen(skb
), sizeof(_ih
), &_ih
);
221 if (LOG_INVALID(IPPROTO_ICMP
))
222 nf_log_packet(PF_INET
, 0, skb
, NULL
, NULL
, NULL
,
223 "nf_ct_icmp: short packet ");
227 /* See ip_conntrack_proto_tcp.c */
228 if (nf_conntrack_checksum
&& hooknum
== NF_IP_PRE_ROUTING
&&
229 nf_ip_checksum(skb
, hooknum
, dataoff
, 0)) {
230 if (LOG_INVALID(IPPROTO_ICMP
))
231 nf_log_packet(PF_INET
, 0, skb
, NULL
, NULL
, NULL
,
232 "nf_ct_icmp: bad HW ICMP checksum ");
237 * 18 is the highest 'known' ICMP type. Anything else is a mystery
239 * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
242 if (icmph
->type
> NR_ICMP_TYPES
) {
243 if (LOG_INVALID(IPPROTO_ICMP
))
244 nf_log_packet(PF_INET
, 0, skb
, NULL
, NULL
, NULL
,
245 "nf_ct_icmp: invalid ICMP type ");
249 /* Need to track icmp error message? */
250 if (icmph
->type
!= ICMP_DEST_UNREACH
251 && icmph
->type
!= ICMP_SOURCE_QUENCH
252 && icmph
->type
!= ICMP_TIME_EXCEEDED
253 && icmph
->type
!= ICMP_PARAMETERPROB
254 && icmph
->type
!= ICMP_REDIRECT
)
257 return icmp_error_message(skb
, ctinfo
, hooknum
);
260 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
262 #include <linux/netfilter/nfnetlink.h>
263 #include <linux/netfilter/nfnetlink_conntrack.h>
265 static int icmp_tuple_to_nfattr(struct sk_buff
*skb
,
266 const struct nf_conntrack_tuple
*t
)
268 NFA_PUT(skb
, CTA_PROTO_ICMP_ID
, sizeof(u_int16_t
),
270 NFA_PUT(skb
, CTA_PROTO_ICMP_TYPE
, sizeof(u_int8_t
),
271 &t
->dst
.u
.icmp
.type
);
272 NFA_PUT(skb
, CTA_PROTO_ICMP_CODE
, sizeof(u_int8_t
),
273 &t
->dst
.u
.icmp
.code
);
281 static const size_t cta_min_proto
[CTA_PROTO_MAX
] = {
282 [CTA_PROTO_ICMP_TYPE
-1] = sizeof(u_int8_t
),
283 [CTA_PROTO_ICMP_CODE
-1] = sizeof(u_int8_t
),
284 [CTA_PROTO_ICMP_ID
-1] = sizeof(u_int16_t
)
287 static int icmp_nfattr_to_tuple(struct nfattr
*tb
[],
288 struct nf_conntrack_tuple
*tuple
)
290 if (!tb
[CTA_PROTO_ICMP_TYPE
-1]
291 || !tb
[CTA_PROTO_ICMP_CODE
-1]
292 || !tb
[CTA_PROTO_ICMP_ID
-1])
295 if (nfattr_bad_size(tb
, CTA_PROTO_MAX
, cta_min_proto
))
298 tuple
->dst
.u
.icmp
.type
=
299 *(u_int8_t
*)NFA_DATA(tb
[CTA_PROTO_ICMP_TYPE
-1]);
300 tuple
->dst
.u
.icmp
.code
=
301 *(u_int8_t
*)NFA_DATA(tb
[CTA_PROTO_ICMP_CODE
-1]);
302 tuple
->src
.u
.icmp
.id
=
303 *(__be16
*)NFA_DATA(tb
[CTA_PROTO_ICMP_ID
-1]);
305 if (tuple
->dst
.u
.icmp
.type
>= sizeof(invmap
)
306 || !invmap
[tuple
->dst
.u
.icmp
.type
])
314 static struct ctl_table_header
*icmp_sysctl_header
;
315 static struct ctl_table icmp_sysctl_table
[] = {
317 .ctl_name
= NET_NF_CONNTRACK_ICMP_TIMEOUT
,
318 .procname
= "nf_conntrack_icmp_timeout",
319 .data
= &nf_ct_icmp_timeout
,
320 .maxlen
= sizeof(unsigned int),
322 .proc_handler
= &proc_dointvec_jiffies
,
328 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
329 static struct ctl_table icmp_compat_sysctl_table
[] = {
331 .ctl_name
= NET_IPV4_NF_CONNTRACK_ICMP_TIMEOUT
,
332 .procname
= "ip_conntrack_icmp_timeout",
333 .data
= &nf_ct_icmp_timeout
,
334 .maxlen
= sizeof(unsigned int),
336 .proc_handler
= &proc_dointvec_jiffies
,
342 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
343 #endif /* CONFIG_SYSCTL */
345 struct nf_conntrack_l4proto nf_conntrack_l4proto_icmp
=
348 .l4proto
= IPPROTO_ICMP
,
350 .pkt_to_tuple
= icmp_pkt_to_tuple
,
351 .invert_tuple
= icmp_invert_tuple
,
352 .print_tuple
= icmp_print_tuple
,
353 .print_conntrack
= icmp_print_conntrack
,
354 .packet
= icmp_packet
,
359 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
360 .tuple_to_nfattr
= icmp_tuple_to_nfattr
,
361 .nfattr_to_tuple
= icmp_nfattr_to_tuple
,
364 .ctl_table_header
= &icmp_sysctl_header
,
365 .ctl_table
= icmp_sysctl_table
,
366 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
367 .ctl_compat_table
= icmp_compat_sysctl_table
,
371 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_icmp
);