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
;
139 struct nf_conntrack_l4proto
*innerproto
;
140 struct nf_conntrack_tuple_hash
*h
;
142 NF_CT_ASSERT(skb
->nfct
== NULL
);
144 /* Are they talking about one of our connections? */
145 if (!nf_ct_get_tuplepr(skb
,
146 skb_network_offset(skb
) + ip_hdrlen(skb
)
147 + sizeof(struct icmphdr
),
148 PF_INET
, &origtuple
)) {
149 pr_debug("icmp_error_message: failed to get tuple\n");
153 /* rcu_read_lock()ed by nf_hook_slow */
154 innerproto
= __nf_ct_l4proto_find(PF_INET
, origtuple
.dst
.protonum
);
156 /* Ordinarily, we'd expect the inverted tupleproto, but it's
157 been preserved inside the ICMP. */
158 if (!nf_ct_invert_tuple(&innertuple
, &origtuple
,
159 &nf_conntrack_l3proto_ipv4
, innerproto
)) {
160 pr_debug("icmp_error_message: no match\n");
164 *ctinfo
= IP_CT_RELATED
;
166 h
= nf_conntrack_find_get(&innertuple
);
168 pr_debug("icmp_error_message: no match\n");
172 if (NF_CT_DIRECTION(h
) == IP_CT_DIR_REPLY
)
173 *ctinfo
+= IP_CT_IS_REPLY
;
175 /* Update skb to refer to this connection */
176 skb
->nfct
= &nf_ct_tuplehash_to_ctrack(h
)->ct_general
;
177 skb
->nfctinfo
= *ctinfo
;
181 /* Small and modified version of icmp_rcv */
183 icmp_error(struct sk_buff
*skb
, unsigned int dataoff
,
184 enum ip_conntrack_info
*ctinfo
, int pf
, unsigned int hooknum
)
186 struct icmphdr _ih
, *icmph
;
188 /* Not enough header? */
189 icmph
= skb_header_pointer(skb
, ip_hdrlen(skb
), sizeof(_ih
), &_ih
);
191 if (LOG_INVALID(IPPROTO_ICMP
))
192 nf_log_packet(PF_INET
, 0, skb
, NULL
, NULL
, NULL
,
193 "nf_ct_icmp: short packet ");
197 /* See ip_conntrack_proto_tcp.c */
198 if (nf_conntrack_checksum
&& hooknum
== NF_IP_PRE_ROUTING
&&
199 nf_ip_checksum(skb
, hooknum
, dataoff
, 0)) {
200 if (LOG_INVALID(IPPROTO_ICMP
))
201 nf_log_packet(PF_INET
, 0, skb
, NULL
, NULL
, NULL
,
202 "nf_ct_icmp: bad HW ICMP checksum ");
207 * 18 is the highest 'known' ICMP type. Anything else is a mystery
209 * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
212 if (icmph
->type
> NR_ICMP_TYPES
) {
213 if (LOG_INVALID(IPPROTO_ICMP
))
214 nf_log_packet(PF_INET
, 0, skb
, NULL
, NULL
, NULL
,
215 "nf_ct_icmp: invalid ICMP type ");
219 /* Need to track icmp error message? */
220 if (icmph
->type
!= ICMP_DEST_UNREACH
221 && icmph
->type
!= ICMP_SOURCE_QUENCH
222 && icmph
->type
!= ICMP_TIME_EXCEEDED
223 && icmph
->type
!= ICMP_PARAMETERPROB
224 && icmph
->type
!= ICMP_REDIRECT
)
227 return icmp_error_message(skb
, ctinfo
, hooknum
);
230 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
232 #include <linux/netfilter/nfnetlink.h>
233 #include <linux/netfilter/nfnetlink_conntrack.h>
235 static int icmp_tuple_to_nlattr(struct sk_buff
*skb
,
236 const struct nf_conntrack_tuple
*t
)
238 NLA_PUT(skb
, CTA_PROTO_ICMP_ID
, sizeof(u_int16_t
),
240 NLA_PUT(skb
, CTA_PROTO_ICMP_TYPE
, sizeof(u_int8_t
),
241 &t
->dst
.u
.icmp
.type
);
242 NLA_PUT(skb
, CTA_PROTO_ICMP_CODE
, sizeof(u_int8_t
),
243 &t
->dst
.u
.icmp
.code
);
251 static const struct nla_policy icmp_nla_policy
[CTA_PROTO_MAX
+1] = {
252 [CTA_PROTO_ICMP_TYPE
] = { .type
= NLA_U8
},
253 [CTA_PROTO_ICMP_CODE
] = { .type
= NLA_U8
},
254 [CTA_PROTO_ICMP_ID
] = { .type
= NLA_U16
},
257 static int icmp_nlattr_to_tuple(struct nlattr
*tb
[],
258 struct nf_conntrack_tuple
*tuple
)
260 if (!tb
[CTA_PROTO_ICMP_TYPE
]
261 || !tb
[CTA_PROTO_ICMP_CODE
]
262 || !tb
[CTA_PROTO_ICMP_ID
])
265 tuple
->dst
.u
.icmp
.type
=
266 *(u_int8_t
*)nla_data(tb
[CTA_PROTO_ICMP_TYPE
]);
267 tuple
->dst
.u
.icmp
.code
=
268 *(u_int8_t
*)nla_data(tb
[CTA_PROTO_ICMP_CODE
]);
269 tuple
->src
.u
.icmp
.id
=
270 *(__be16
*)nla_data(tb
[CTA_PROTO_ICMP_ID
]);
272 if (tuple
->dst
.u
.icmp
.type
>= sizeof(invmap
)
273 || !invmap
[tuple
->dst
.u
.icmp
.type
])
281 static struct ctl_table_header
*icmp_sysctl_header
;
282 static struct ctl_table icmp_sysctl_table
[] = {
284 .procname
= "nf_conntrack_icmp_timeout",
285 .data
= &nf_ct_icmp_timeout
,
286 .maxlen
= sizeof(unsigned int),
288 .proc_handler
= &proc_dointvec_jiffies
,
294 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
295 static struct ctl_table icmp_compat_sysctl_table
[] = {
297 .procname
= "ip_conntrack_icmp_timeout",
298 .data
= &nf_ct_icmp_timeout
,
299 .maxlen
= sizeof(unsigned int),
301 .proc_handler
= &proc_dointvec_jiffies
,
307 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
308 #endif /* CONFIG_SYSCTL */
310 struct nf_conntrack_l4proto nf_conntrack_l4proto_icmp __read_mostly
=
313 .l4proto
= IPPROTO_ICMP
,
315 .pkt_to_tuple
= icmp_pkt_to_tuple
,
316 .invert_tuple
= icmp_invert_tuple
,
317 .print_tuple
= icmp_print_tuple
,
318 .print_conntrack
= icmp_print_conntrack
,
319 .packet
= icmp_packet
,
324 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
325 .tuple_to_nlattr
= icmp_tuple_to_nlattr
,
326 .nlattr_to_tuple
= icmp_nlattr_to_tuple
,
327 .nla_policy
= icmp_nla_policy
,
330 .ctl_table_header
= &icmp_sysctl_header
,
331 .ctl_table
= icmp_sysctl_table
,
332 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
333 .ctl_compat_table
= icmp_compat_sysctl_table
,