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
;
27 #define DEBUGP(format, args...)
30 static int icmp_pkt_to_tuple(const struct sk_buff
*skb
,
32 struct nf_conntrack_tuple
*tuple
)
34 struct icmphdr _hdr
, *hp
;
36 hp
= skb_header_pointer(skb
, dataoff
, sizeof(_hdr
), &_hdr
);
40 tuple
->dst
.u
.icmp
.type
= hp
->type
;
41 tuple
->src
.u
.icmp
.id
= hp
->un
.echo
.id
;
42 tuple
->dst
.u
.icmp
.code
= hp
->code
;
47 /* Add 1; spaces filled with 0. */
48 static const u_int8_t invmap
[] = {
49 [ICMP_ECHO
] = ICMP_ECHOREPLY
+ 1,
50 [ICMP_ECHOREPLY
] = ICMP_ECHO
+ 1,
51 [ICMP_TIMESTAMP
] = ICMP_TIMESTAMPREPLY
+ 1,
52 [ICMP_TIMESTAMPREPLY
] = ICMP_TIMESTAMP
+ 1,
53 [ICMP_INFO_REQUEST
] = ICMP_INFO_REPLY
+ 1,
54 [ICMP_INFO_REPLY
] = ICMP_INFO_REQUEST
+ 1,
55 [ICMP_ADDRESS
] = ICMP_ADDRESSREPLY
+ 1,
56 [ICMP_ADDRESSREPLY
] = ICMP_ADDRESS
+ 1
59 static int icmp_invert_tuple(struct nf_conntrack_tuple
*tuple
,
60 const struct nf_conntrack_tuple
*orig
)
62 if (orig
->dst
.u
.icmp
.type
>= sizeof(invmap
)
63 || !invmap
[orig
->dst
.u
.icmp
.type
])
66 tuple
->src
.u
.icmp
.id
= orig
->src
.u
.icmp
.id
;
67 tuple
->dst
.u
.icmp
.type
= invmap
[orig
->dst
.u
.icmp
.type
] - 1;
68 tuple
->dst
.u
.icmp
.code
= orig
->dst
.u
.icmp
.code
;
72 /* Print out the per-protocol part of the tuple. */
73 static int icmp_print_tuple(struct seq_file
*s
,
74 const struct nf_conntrack_tuple
*tuple
)
76 return seq_printf(s
, "type=%u code=%u id=%u ",
77 tuple
->dst
.u
.icmp
.type
,
78 tuple
->dst
.u
.icmp
.code
,
79 ntohs(tuple
->src
.u
.icmp
.id
));
82 /* Returns verdict for packet, or -1 for invalid. */
83 static int icmp_packet(struct nf_conn
*ct
,
84 const struct sk_buff
*skb
,
86 enum ip_conntrack_info ctinfo
,
90 /* Try to delete connection immediately after all replies:
91 won't actually vanish as we still have skb, and del_timer
92 means this will only run once even if count hits zero twice
93 (theoretically possible with SMP) */
94 if (CTINFO2DIR(ctinfo
) == IP_CT_DIR_REPLY
) {
95 if (atomic_dec_and_test(&ct
->proto
.icmp
.count
)
96 && del_timer(&ct
->timeout
))
97 ct
->timeout
.function((unsigned long)ct
);
99 atomic_inc(&ct
->proto
.icmp
.count
);
100 nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE
, skb
);
101 nf_ct_refresh_acct(ct
, ctinfo
, skb
, nf_ct_icmp_timeout
);
107 /* Called when a new connection for this protocol found. */
108 static int icmp_new(struct nf_conn
*conntrack
,
109 const struct sk_buff
*skb
, unsigned int dataoff
)
111 static const u_int8_t valid_new
[] = {
113 [ICMP_TIMESTAMP
] = 1,
114 [ICMP_INFO_REQUEST
] = 1,
118 if (conntrack
->tuplehash
[0].tuple
.dst
.u
.icmp
.type
>= sizeof(valid_new
)
119 || !valid_new
[conntrack
->tuplehash
[0].tuple
.dst
.u
.icmp
.type
]) {
120 /* Can't create a new ICMP `conn' with this. */
121 DEBUGP("icmp: can't create new conn with type %u\n",
122 conntrack
->tuplehash
[0].tuple
.dst
.u
.icmp
.type
);
123 NF_CT_DUMP_TUPLE(&conntrack
->tuplehash
[0].tuple
);
126 atomic_set(&conntrack
->proto
.icmp
.count
, 0);
130 extern struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4
;
131 /* Returns conntrack if it dealt with ICMP, and filled in skb fields */
133 icmp_error_message(struct sk_buff
*skb
,
134 enum ip_conntrack_info
*ctinfo
,
135 unsigned int hooknum
)
137 struct nf_conntrack_tuple innertuple
, origtuple
;
142 struct nf_conntrack_l4proto
*innerproto
;
143 struct nf_conntrack_tuple_hash
*h
;
146 NF_CT_ASSERT(skb
->nfct
== NULL
);
148 /* Not enough header? */
149 inside
= skb_header_pointer(skb
, ip_hdrlen(skb
), sizeof(_in
), &_in
);
153 /* Ignore ICMP's containing fragments (shouldn't happen) */
154 if (inside
->ip
.frag_off
& htons(IP_OFFSET
)) {
155 DEBUGP("icmp_error_message: fragment of proto %u\n",
156 inside
->ip
.protocol
);
160 /* rcu_read_lock()ed by nf_hook_slow */
161 innerproto
= __nf_ct_l4proto_find(PF_INET
, inside
->ip
.protocol
);
163 dataoff
= ip_hdrlen(skb
) + sizeof(inside
->icmp
);
164 /* Are they talking about one of our connections? */
165 if (!nf_ct_get_tuple(skb
, dataoff
, dataoff
+ inside
->ip
.ihl
*4, PF_INET
,
166 inside
->ip
.protocol
, &origtuple
,
167 &nf_conntrack_l3proto_ipv4
, innerproto
)) {
168 DEBUGP("icmp_error_message: ! get_tuple p=%u",
169 inside
->ip
.protocol
);
173 /* Ordinarily, we'd expect the inverted tupleproto, but it's
174 been preserved inside the ICMP. */
175 if (!nf_ct_invert_tuple(&innertuple
, &origtuple
,
176 &nf_conntrack_l3proto_ipv4
, innerproto
)) {
177 DEBUGP("icmp_error_message: no match\n");
181 *ctinfo
= IP_CT_RELATED
;
183 h
= nf_conntrack_find_get(&innertuple
, NULL
);
185 DEBUGP("icmp_error_message: no match\n");
189 if (NF_CT_DIRECTION(h
) == IP_CT_DIR_REPLY
)
190 *ctinfo
+= IP_CT_IS_REPLY
;
192 /* Update skb to refer to this connection */
193 skb
->nfct
= &nf_ct_tuplehash_to_ctrack(h
)->ct_general
;
194 skb
->nfctinfo
= *ctinfo
;
198 /* Small and modified version of icmp_rcv */
200 icmp_error(struct sk_buff
*skb
, unsigned int dataoff
,
201 enum ip_conntrack_info
*ctinfo
, int pf
, unsigned int hooknum
)
203 struct icmphdr _ih
, *icmph
;
205 /* Not enough header? */
206 icmph
= skb_header_pointer(skb
, ip_hdrlen(skb
), sizeof(_ih
), &_ih
);
208 if (LOG_INVALID(IPPROTO_ICMP
))
209 nf_log_packet(PF_INET
, 0, skb
, NULL
, NULL
, NULL
,
210 "nf_ct_icmp: short packet ");
214 /* See ip_conntrack_proto_tcp.c */
215 if (nf_conntrack_checksum
&& hooknum
== NF_IP_PRE_ROUTING
&&
216 nf_ip_checksum(skb
, hooknum
, dataoff
, 0)) {
217 if (LOG_INVALID(IPPROTO_ICMP
))
218 nf_log_packet(PF_INET
, 0, skb
, NULL
, NULL
, NULL
,
219 "nf_ct_icmp: bad HW ICMP checksum ");
224 * 18 is the highest 'known' ICMP type. Anything else is a mystery
226 * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
229 if (icmph
->type
> NR_ICMP_TYPES
) {
230 if (LOG_INVALID(IPPROTO_ICMP
))
231 nf_log_packet(PF_INET
, 0, skb
, NULL
, NULL
, NULL
,
232 "nf_ct_icmp: invalid ICMP type ");
236 /* Need to track icmp error message? */
237 if (icmph
->type
!= ICMP_DEST_UNREACH
238 && icmph
->type
!= ICMP_SOURCE_QUENCH
239 && icmph
->type
!= ICMP_TIME_EXCEEDED
240 && icmph
->type
!= ICMP_PARAMETERPROB
241 && icmph
->type
!= ICMP_REDIRECT
)
244 return icmp_error_message(skb
, ctinfo
, hooknum
);
247 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
249 #include <linux/netfilter/nfnetlink.h>
250 #include <linux/netfilter/nfnetlink_conntrack.h>
252 static int icmp_tuple_to_nfattr(struct sk_buff
*skb
,
253 const struct nf_conntrack_tuple
*t
)
255 NFA_PUT(skb
, CTA_PROTO_ICMP_ID
, sizeof(u_int16_t
),
257 NFA_PUT(skb
, CTA_PROTO_ICMP_TYPE
, sizeof(u_int8_t
),
258 &t
->dst
.u
.icmp
.type
);
259 NFA_PUT(skb
, CTA_PROTO_ICMP_CODE
, sizeof(u_int8_t
),
260 &t
->dst
.u
.icmp
.code
);
268 static const size_t cta_min_proto
[CTA_PROTO_MAX
] = {
269 [CTA_PROTO_ICMP_TYPE
-1] = sizeof(u_int8_t
),
270 [CTA_PROTO_ICMP_CODE
-1] = sizeof(u_int8_t
),
271 [CTA_PROTO_ICMP_ID
-1] = sizeof(u_int16_t
)
274 static int icmp_nfattr_to_tuple(struct nfattr
*tb
[],
275 struct nf_conntrack_tuple
*tuple
)
277 if (!tb
[CTA_PROTO_ICMP_TYPE
-1]
278 || !tb
[CTA_PROTO_ICMP_CODE
-1]
279 || !tb
[CTA_PROTO_ICMP_ID
-1])
282 if (nfattr_bad_size(tb
, CTA_PROTO_MAX
, cta_min_proto
))
285 tuple
->dst
.u
.icmp
.type
=
286 *(u_int8_t
*)NFA_DATA(tb
[CTA_PROTO_ICMP_TYPE
-1]);
287 tuple
->dst
.u
.icmp
.code
=
288 *(u_int8_t
*)NFA_DATA(tb
[CTA_PROTO_ICMP_CODE
-1]);
289 tuple
->src
.u
.icmp
.id
=
290 *(__be16
*)NFA_DATA(tb
[CTA_PROTO_ICMP_ID
-1]);
292 if (tuple
->dst
.u
.icmp
.type
>= sizeof(invmap
)
293 || !invmap
[tuple
->dst
.u
.icmp
.type
])
301 static struct ctl_table_header
*icmp_sysctl_header
;
302 static struct ctl_table icmp_sysctl_table
[] = {
304 .ctl_name
= NET_NF_CONNTRACK_ICMP_TIMEOUT
,
305 .procname
= "nf_conntrack_icmp_timeout",
306 .data
= &nf_ct_icmp_timeout
,
307 .maxlen
= sizeof(unsigned int),
309 .proc_handler
= &proc_dointvec_jiffies
,
315 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
316 static struct ctl_table icmp_compat_sysctl_table
[] = {
318 .ctl_name
= NET_IPV4_NF_CONNTRACK_ICMP_TIMEOUT
,
319 .procname
= "ip_conntrack_icmp_timeout",
320 .data
= &nf_ct_icmp_timeout
,
321 .maxlen
= sizeof(unsigned int),
323 .proc_handler
= &proc_dointvec_jiffies
,
329 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
330 #endif /* CONFIG_SYSCTL */
332 struct nf_conntrack_l4proto nf_conntrack_l4proto_icmp
=
335 .l4proto
= IPPROTO_ICMP
,
337 .pkt_to_tuple
= icmp_pkt_to_tuple
,
338 .invert_tuple
= icmp_invert_tuple
,
339 .print_tuple
= icmp_print_tuple
,
340 .packet
= icmp_packet
,
345 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
346 .tuple_to_nfattr
= icmp_tuple_to_nfattr
,
347 .nfattr_to_tuple
= icmp_nfattr_to_tuple
,
350 .ctl_table_header
= &icmp_sysctl_header
,
351 .ctl_table
= icmp_sysctl_table
,
352 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
353 .ctl_compat_table
= icmp_compat_sysctl_table
,
357 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_icmp
);