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>
15 #include <linux/skbuff.h>
17 #include <net/checksum.h>
18 #include <linux/netfilter_ipv4.h>
19 #include <linux/netfilter_ipv4/ip_conntrack.h>
20 #include <linux/netfilter_ipv4/ip_conntrack_core.h>
21 #include <linux/netfilter_ipv4/ip_conntrack_protocol.h>
23 unsigned int ip_ct_icmp_timeout __read_mostly
= 30*HZ
;
28 #define DEBUGP(format, args...)
31 static int icmp_pkt_to_tuple(const struct sk_buff
*skb
,
33 struct ip_conntrack_tuple
*tuple
)
35 struct icmphdr _hdr
, *hp
;
37 hp
= skb_header_pointer(skb
, dataoff
, sizeof(_hdr
), &_hdr
);
41 tuple
->dst
.u
.icmp
.type
= hp
->type
;
42 tuple
->src
.u
.icmp
.id
= hp
->un
.echo
.id
;
43 tuple
->dst
.u
.icmp
.code
= hp
->code
;
48 /* Add 1; spaces filled with 0. */
49 static const u_int8_t invmap
[] = {
50 [ICMP_ECHO
] = ICMP_ECHOREPLY
+ 1,
51 [ICMP_ECHOREPLY
] = ICMP_ECHO
+ 1,
52 [ICMP_TIMESTAMP
] = ICMP_TIMESTAMPREPLY
+ 1,
53 [ICMP_TIMESTAMPREPLY
] = ICMP_TIMESTAMP
+ 1,
54 [ICMP_INFO_REQUEST
] = ICMP_INFO_REPLY
+ 1,
55 [ICMP_INFO_REPLY
] = ICMP_INFO_REQUEST
+ 1,
56 [ICMP_ADDRESS
] = ICMP_ADDRESSREPLY
+ 1,
57 [ICMP_ADDRESSREPLY
] = ICMP_ADDRESS
+ 1
60 static int icmp_invert_tuple(struct ip_conntrack_tuple
*tuple
,
61 const struct ip_conntrack_tuple
*orig
)
63 if (orig
->dst
.u
.icmp
.type
>= sizeof(invmap
)
64 || !invmap
[orig
->dst
.u
.icmp
.type
])
67 tuple
->src
.u
.icmp
.id
= orig
->src
.u
.icmp
.id
;
68 tuple
->dst
.u
.icmp
.type
= invmap
[orig
->dst
.u
.icmp
.type
] - 1;
69 tuple
->dst
.u
.icmp
.code
= orig
->dst
.u
.icmp
.code
;
73 /* Print out the per-protocol part of the tuple. */
74 static int icmp_print_tuple(struct seq_file
*s
,
75 const struct ip_conntrack_tuple
*tuple
)
77 return seq_printf(s
, "type=%u code=%u id=%u ",
78 tuple
->dst
.u
.icmp
.type
,
79 tuple
->dst
.u
.icmp
.code
,
80 ntohs(tuple
->src
.u
.icmp
.id
));
83 /* Print out the private part of the conntrack. */
84 static int icmp_print_conntrack(struct seq_file
*s
,
85 const struct ip_conntrack
*conntrack
)
90 /* Returns verdict for packet, or -1 for invalid. */
91 static int icmp_packet(struct ip_conntrack
*ct
,
92 const struct sk_buff
*skb
,
93 enum ip_conntrack_info ctinfo
)
95 /* Try to delete connection immediately after all replies:
96 won't actually vanish as we still have skb, and del_timer
97 means this will only run once even if count hits zero twice
98 (theoretically possible with SMP) */
99 if (CTINFO2DIR(ctinfo
) == IP_CT_DIR_REPLY
) {
100 if (atomic_dec_and_test(&ct
->proto
.icmp
.count
)
101 && del_timer(&ct
->timeout
))
102 ct
->timeout
.function((unsigned long)ct
);
104 atomic_inc(&ct
->proto
.icmp
.count
);
105 ip_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE
, skb
);
106 ip_ct_refresh_acct(ct
, ctinfo
, skb
, ip_ct_icmp_timeout
);
112 /* Called when a new connection for this protocol found. */
113 static int icmp_new(struct ip_conntrack
*conntrack
,
114 const struct sk_buff
*skb
)
116 static const u_int8_t valid_new
[] = {
118 [ICMP_TIMESTAMP
] = 1,
119 [ICMP_INFO_REQUEST
] = 1,
123 if (conntrack
->tuplehash
[0].tuple
.dst
.u
.icmp
.type
>= sizeof(valid_new
)
124 || !valid_new
[conntrack
->tuplehash
[0].tuple
.dst
.u
.icmp
.type
]) {
125 /* Can't create a new ICMP `conn' with this. */
126 DEBUGP("icmp: can't create new conn with type %u\n",
127 conntrack
->tuplehash
[0].tuple
.dst
.u
.icmp
.type
);
128 DUMP_TUPLE(&conntrack
->tuplehash
[0].tuple
);
131 atomic_set(&conntrack
->proto
.icmp
.count
, 0);
136 icmp_error_message(struct sk_buff
*skb
,
137 enum ip_conntrack_info
*ctinfo
,
138 unsigned int hooknum
)
140 struct ip_conntrack_tuple innertuple
, origtuple
;
145 struct ip_conntrack_protocol
*innerproto
;
146 struct ip_conntrack_tuple_hash
*h
;
149 IP_NF_ASSERT(skb
->nfct
== NULL
);
151 /* Not enough header? */
152 inside
= skb_header_pointer(skb
, ip_hdrlen(skb
), sizeof(_in
), &_in
);
156 /* Ignore ICMP's containing fragments (shouldn't happen) */
157 if (inside
->ip
.frag_off
& htons(IP_OFFSET
)) {
158 DEBUGP("icmp_error_track: fragment of proto %u\n",
159 inside
->ip
.protocol
);
163 innerproto
= ip_conntrack_proto_find_get(inside
->ip
.protocol
);
164 dataoff
= ip_hdrlen(skb
) + sizeof(inside
->icmp
) + inside
->ip
.ihl
* 4;
165 /* Are they talking about one of our connections? */
166 if (!ip_ct_get_tuple(&inside
->ip
, skb
, dataoff
, &origtuple
, innerproto
)) {
167 DEBUGP("icmp_error: ! get_tuple p=%u", inside
->ip
.protocol
);
168 ip_conntrack_proto_put(innerproto
);
172 /* Ordinarily, we'd expect the inverted tupleproto, but it's
173 been preserved inside the ICMP. */
174 if (!ip_ct_invert_tuple(&innertuple
, &origtuple
, innerproto
)) {
175 DEBUGP("icmp_error_track: Can't invert tuple\n");
176 ip_conntrack_proto_put(innerproto
);
179 ip_conntrack_proto_put(innerproto
);
181 *ctinfo
= IP_CT_RELATED
;
183 h
= ip_conntrack_find_get(&innertuple
, NULL
);
185 /* Locally generated ICMPs will match inverted if they
186 haven't been SNAT'ed yet */
187 /* FIXME: NAT code has to handle half-done double NAT --RR */
188 if (hooknum
== NF_IP_LOCAL_OUT
)
189 h
= ip_conntrack_find_get(&origtuple
, NULL
);
192 DEBUGP("icmp_error_track: no match\n");
195 /* Reverse direction from that found */
196 if (DIRECTION(h
) != IP_CT_DIR_REPLY
)
197 *ctinfo
+= IP_CT_IS_REPLY
;
199 if (DIRECTION(h
) == IP_CT_DIR_REPLY
)
200 *ctinfo
+= IP_CT_IS_REPLY
;
203 /* Update skb to refer to this connection */
204 skb
->nfct
= &tuplehash_to_ctrack(h
)->ct_general
;
205 skb
->nfctinfo
= *ctinfo
;
209 /* Small and modified version of icmp_rcv */
211 icmp_error(struct sk_buff
*skb
, enum ip_conntrack_info
*ctinfo
,
212 unsigned int hooknum
)
214 struct icmphdr _ih
, *icmph
;
216 /* Not enough header? */
217 icmph
= skb_header_pointer(skb
, ip_hdrlen(skb
), sizeof(_ih
), &_ih
);
219 if (LOG_INVALID(IPPROTO_ICMP
))
220 nf_log_packet(PF_INET
, 0, skb
, NULL
, NULL
, NULL
,
221 "ip_ct_icmp: short packet ");
225 /* See ip_conntrack_proto_tcp.c */
226 if (ip_conntrack_checksum
&& hooknum
== NF_IP_PRE_ROUTING
&&
227 nf_ip_checksum(skb
, hooknum
, ip_hdrlen(skb
), 0)) {
228 if (LOG_INVALID(IPPROTO_ICMP
))
229 nf_log_packet(PF_INET
, 0, skb
, NULL
, NULL
, NULL
,
230 "ip_ct_icmp: bad ICMP checksum ");
235 * 18 is the highest 'known' ICMP type. Anything else is a mystery
237 * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
240 if (icmph
->type
> NR_ICMP_TYPES
) {
241 if (LOG_INVALID(IPPROTO_ICMP
))
242 nf_log_packet(PF_INET
, 0, skb
, NULL
, NULL
, NULL
,
243 "ip_ct_icmp: invalid ICMP type ");
247 /* Need to track icmp error message? */
248 if (icmph
->type
!= ICMP_DEST_UNREACH
249 && icmph
->type
!= ICMP_SOURCE_QUENCH
250 && icmph
->type
!= ICMP_TIME_EXCEEDED
251 && icmph
->type
!= ICMP_PARAMETERPROB
252 && icmph
->type
!= ICMP_REDIRECT
)
255 return icmp_error_message(skb
, ctinfo
, hooknum
);
258 #if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
259 defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
260 static int icmp_tuple_to_nfattr(struct sk_buff
*skb
,
261 const struct ip_conntrack_tuple
*t
)
263 NFA_PUT(skb
, CTA_PROTO_ICMP_ID
, sizeof(__be16
),
265 NFA_PUT(skb
, CTA_PROTO_ICMP_TYPE
, sizeof(u_int8_t
),
266 &t
->dst
.u
.icmp
.type
);
267 NFA_PUT(skb
, CTA_PROTO_ICMP_CODE
, sizeof(u_int8_t
),
268 &t
->dst
.u
.icmp
.code
);
276 static int icmp_nfattr_to_tuple(struct nfattr
*tb
[],
277 struct ip_conntrack_tuple
*tuple
)
279 if (!tb
[CTA_PROTO_ICMP_TYPE
-1]
280 || !tb
[CTA_PROTO_ICMP_CODE
-1]
281 || !tb
[CTA_PROTO_ICMP_ID
-1])
284 tuple
->dst
.u
.icmp
.type
=
285 *(u_int8_t
*)NFA_DATA(tb
[CTA_PROTO_ICMP_TYPE
-1]);
286 tuple
->dst
.u
.icmp
.code
=
287 *(u_int8_t
*)NFA_DATA(tb
[CTA_PROTO_ICMP_CODE
-1]);
288 tuple
->src
.u
.icmp
.id
=
289 *(__be16
*)NFA_DATA(tb
[CTA_PROTO_ICMP_ID
-1]);
291 if (tuple
->dst
.u
.icmp
.type
>= sizeof(invmap
)
292 || !invmap
[tuple
->dst
.u
.icmp
.type
])
299 struct ip_conntrack_protocol ip_conntrack_protocol_icmp
=
301 .proto
= IPPROTO_ICMP
,
303 .pkt_to_tuple
= icmp_pkt_to_tuple
,
304 .invert_tuple
= icmp_invert_tuple
,
305 .print_tuple
= icmp_print_tuple
,
306 .print_conntrack
= icmp_print_conntrack
,
307 .packet
= icmp_packet
,
310 #if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
311 defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
312 .tuple_to_nfattr
= icmp_tuple_to_nfattr
,
313 .nfattr_to_tuple
= icmp_nfattr_to_tuple
,