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>
21 #include <net/netfilter/nf_log.h>
23 static unsigned long nf_ct_icmp_timeout __read_mostly
= 30*HZ
;
25 static bool icmp_pkt_to_tuple(const struct sk_buff
*skb
, unsigned int dataoff
,
26 struct nf_conntrack_tuple
*tuple
)
28 const struct icmphdr
*hp
;
31 hp
= skb_header_pointer(skb
, dataoff
, sizeof(_hdr
), &_hdr
);
35 tuple
->dst
.u
.icmp
.type
= hp
->type
;
36 tuple
->src
.u
.icmp
.id
= hp
->un
.echo
.id
;
37 tuple
->dst
.u
.icmp
.code
= hp
->code
;
42 /* Add 1; spaces filled with 0. */
43 static const u_int8_t invmap
[] = {
44 [ICMP_ECHO
] = ICMP_ECHOREPLY
+ 1,
45 [ICMP_ECHOREPLY
] = ICMP_ECHO
+ 1,
46 [ICMP_TIMESTAMP
] = ICMP_TIMESTAMPREPLY
+ 1,
47 [ICMP_TIMESTAMPREPLY
] = ICMP_TIMESTAMP
+ 1,
48 [ICMP_INFO_REQUEST
] = ICMP_INFO_REPLY
+ 1,
49 [ICMP_INFO_REPLY
] = ICMP_INFO_REQUEST
+ 1,
50 [ICMP_ADDRESS
] = ICMP_ADDRESSREPLY
+ 1,
51 [ICMP_ADDRESSREPLY
] = ICMP_ADDRESS
+ 1
54 static bool icmp_invert_tuple(struct nf_conntrack_tuple
*tuple
,
55 const struct nf_conntrack_tuple
*orig
)
57 if (orig
->dst
.u
.icmp
.type
>= sizeof(invmap
)
58 || !invmap
[orig
->dst
.u
.icmp
.type
])
61 tuple
->src
.u
.icmp
.id
= orig
->src
.u
.icmp
.id
;
62 tuple
->dst
.u
.icmp
.type
= invmap
[orig
->dst
.u
.icmp
.type
] - 1;
63 tuple
->dst
.u
.icmp
.code
= orig
->dst
.u
.icmp
.code
;
67 /* Print out the per-protocol part of the tuple. */
68 static int icmp_print_tuple(struct seq_file
*s
,
69 const struct nf_conntrack_tuple
*tuple
)
71 return seq_printf(s
, "type=%u code=%u id=%u ",
72 tuple
->dst
.u
.icmp
.type
,
73 tuple
->dst
.u
.icmp
.code
,
74 ntohs(tuple
->src
.u
.icmp
.id
));
77 /* Returns verdict for packet, or -1 for invalid. */
78 static int icmp_packet(struct nf_conn
*ct
,
79 const struct sk_buff
*skb
,
81 enum ip_conntrack_info ctinfo
,
85 /* Try to delete connection immediately after all replies:
86 won't actually vanish as we still have skb, and del_timer
87 means this will only run once even if count hits zero twice
88 (theoretically possible with SMP) */
89 if (CTINFO2DIR(ctinfo
) == IP_CT_DIR_REPLY
) {
90 if (atomic_dec_and_test(&ct
->proto
.icmp
.count
)
91 && del_timer(&ct
->timeout
))
92 ct
->timeout
.function((unsigned long)ct
);
94 atomic_inc(&ct
->proto
.icmp
.count
);
95 nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE
, skb
);
96 nf_ct_refresh_acct(ct
, ctinfo
, skb
, nf_ct_icmp_timeout
);
102 /* Called when a new connection for this protocol found. */
103 static bool icmp_new(struct nf_conn
*ct
, const struct sk_buff
*skb
,
104 unsigned int dataoff
)
106 static const u_int8_t valid_new
[] = {
108 [ICMP_TIMESTAMP
] = 1,
109 [ICMP_INFO_REQUEST
] = 1,
113 if (ct
->tuplehash
[0].tuple
.dst
.u
.icmp
.type
>= sizeof(valid_new
)
114 || !valid_new
[ct
->tuplehash
[0].tuple
.dst
.u
.icmp
.type
]) {
115 /* Can't create a new ICMP `conn' with this. */
116 pr_debug("icmp: can't create new conn with type %u\n",
117 ct
->tuplehash
[0].tuple
.dst
.u
.icmp
.type
);
118 NF_CT_DUMP_TUPLE(&ct
->tuplehash
[0].tuple
);
121 atomic_set(&ct
->proto
.icmp
.count
, 0);
125 /* Returns conntrack if it dealt with ICMP, and filled in skb fields */
127 icmp_error_message(struct sk_buff
*skb
,
128 enum ip_conntrack_info
*ctinfo
,
129 unsigned int hooknum
)
131 struct nf_conntrack_tuple innertuple
, origtuple
;
132 const struct nf_conntrack_l4proto
*innerproto
;
133 const struct nf_conntrack_tuple_hash
*h
;
135 NF_CT_ASSERT(skb
->nfct
== NULL
);
137 /* Are they talking about one of our connections? */
138 if (!nf_ct_get_tuplepr(skb
,
139 skb_network_offset(skb
) + ip_hdrlen(skb
)
140 + sizeof(struct icmphdr
),
141 PF_INET
, &origtuple
)) {
142 pr_debug("icmp_error_message: failed to get tuple\n");
146 /* rcu_read_lock()ed by nf_hook_slow */
147 innerproto
= __nf_ct_l4proto_find(PF_INET
, origtuple
.dst
.protonum
);
149 /* Ordinarily, we'd expect the inverted tupleproto, but it's
150 been preserved inside the ICMP. */
151 if (!nf_ct_invert_tuple(&innertuple
, &origtuple
,
152 &nf_conntrack_l3proto_ipv4
, innerproto
)) {
153 pr_debug("icmp_error_message: no match\n");
157 *ctinfo
= IP_CT_RELATED
;
159 h
= nf_conntrack_find_get(&innertuple
);
161 pr_debug("icmp_error_message: no match\n");
165 if (NF_CT_DIRECTION(h
) == IP_CT_DIR_REPLY
)
166 *ctinfo
+= IP_CT_IS_REPLY
;
168 /* Update skb to refer to this connection */
169 skb
->nfct
= &nf_ct_tuplehash_to_ctrack(h
)->ct_general
;
170 skb
->nfctinfo
= *ctinfo
;
174 /* Small and modified version of icmp_rcv */
176 icmp_error(struct sk_buff
*skb
, unsigned int dataoff
,
177 enum ip_conntrack_info
*ctinfo
, int pf
, unsigned int hooknum
)
179 const struct icmphdr
*icmph
;
182 /* Not enough header? */
183 icmph
= skb_header_pointer(skb
, ip_hdrlen(skb
), sizeof(_ih
), &_ih
);
185 if (LOG_INVALID(IPPROTO_ICMP
))
186 nf_log_packet(PF_INET
, 0, skb
, NULL
, NULL
, NULL
,
187 "nf_ct_icmp: short packet ");
191 /* See ip_conntrack_proto_tcp.c */
192 if (nf_conntrack_checksum
&& hooknum
== NF_INET_PRE_ROUTING
&&
193 nf_ip_checksum(skb
, hooknum
, dataoff
, 0)) {
194 if (LOG_INVALID(IPPROTO_ICMP
))
195 nf_log_packet(PF_INET
, 0, skb
, NULL
, NULL
, NULL
,
196 "nf_ct_icmp: bad HW ICMP checksum ");
201 * 18 is the highest 'known' ICMP type. Anything else is a mystery
203 * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
206 if (icmph
->type
> NR_ICMP_TYPES
) {
207 if (LOG_INVALID(IPPROTO_ICMP
))
208 nf_log_packet(PF_INET
, 0, skb
, NULL
, NULL
, NULL
,
209 "nf_ct_icmp: invalid ICMP type ");
213 /* Need to track icmp error message? */
214 if (icmph
->type
!= ICMP_DEST_UNREACH
215 && icmph
->type
!= ICMP_SOURCE_QUENCH
216 && icmph
->type
!= ICMP_TIME_EXCEEDED
217 && icmph
->type
!= ICMP_PARAMETERPROB
218 && icmph
->type
!= ICMP_REDIRECT
)
221 return icmp_error_message(skb
, ctinfo
, hooknum
);
224 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
226 #include <linux/netfilter/nfnetlink.h>
227 #include <linux/netfilter/nfnetlink_conntrack.h>
229 static int icmp_tuple_to_nlattr(struct sk_buff
*skb
,
230 const struct nf_conntrack_tuple
*t
)
232 NLA_PUT_BE16(skb
, CTA_PROTO_ICMP_ID
, t
->src
.u
.icmp
.id
);
233 NLA_PUT_U8(skb
, CTA_PROTO_ICMP_TYPE
, t
->dst
.u
.icmp
.type
);
234 NLA_PUT_U8(skb
, CTA_PROTO_ICMP_CODE
, t
->dst
.u
.icmp
.code
);
242 static const struct nla_policy icmp_nla_policy
[CTA_PROTO_MAX
+1] = {
243 [CTA_PROTO_ICMP_TYPE
] = { .type
= NLA_U8
},
244 [CTA_PROTO_ICMP_CODE
] = { .type
= NLA_U8
},
245 [CTA_PROTO_ICMP_ID
] = { .type
= NLA_U16
},
248 static int icmp_nlattr_to_tuple(struct nlattr
*tb
[],
249 struct nf_conntrack_tuple
*tuple
)
251 if (!tb
[CTA_PROTO_ICMP_TYPE
]
252 || !tb
[CTA_PROTO_ICMP_CODE
]
253 || !tb
[CTA_PROTO_ICMP_ID
])
256 tuple
->dst
.u
.icmp
.type
= nla_get_u8(tb
[CTA_PROTO_ICMP_TYPE
]);
257 tuple
->dst
.u
.icmp
.code
= nla_get_u8(tb
[CTA_PROTO_ICMP_CODE
]);
258 tuple
->src
.u
.icmp
.id
= nla_get_be16(tb
[CTA_PROTO_ICMP_ID
]);
260 if (tuple
->dst
.u
.icmp
.type
>= sizeof(invmap
)
261 || !invmap
[tuple
->dst
.u
.icmp
.type
])
269 static struct ctl_table_header
*icmp_sysctl_header
;
270 static struct ctl_table icmp_sysctl_table
[] = {
272 .procname
= "nf_conntrack_icmp_timeout",
273 .data
= &nf_ct_icmp_timeout
,
274 .maxlen
= sizeof(unsigned int),
276 .proc_handler
= &proc_dointvec_jiffies
,
282 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
283 static struct ctl_table icmp_compat_sysctl_table
[] = {
285 .procname
= "ip_conntrack_icmp_timeout",
286 .data
= &nf_ct_icmp_timeout
,
287 .maxlen
= sizeof(unsigned int),
289 .proc_handler
= &proc_dointvec_jiffies
,
295 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
296 #endif /* CONFIG_SYSCTL */
298 struct nf_conntrack_l4proto nf_conntrack_l4proto_icmp __read_mostly
=
301 .l4proto
= IPPROTO_ICMP
,
303 .pkt_to_tuple
= icmp_pkt_to_tuple
,
304 .invert_tuple
= icmp_invert_tuple
,
305 .print_tuple
= icmp_print_tuple
,
306 .packet
= icmp_packet
,
311 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
312 .tuple_to_nlattr
= icmp_tuple_to_nlattr
,
313 .nlattr_to_tuple
= icmp_nlattr_to_tuple
,
314 .nla_policy
= icmp_nla_policy
,
317 .ctl_table_header
= &icmp_sysctl_header
,
318 .ctl_table
= icmp_sysctl_table
,
319 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
320 .ctl_compat_table
= icmp_compat_sysctl_table
,