1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
3 * (C) 2006-2010 Patrick McHardy <kaber@trash.net>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
10 #include <linux/types.h>
11 #include <linux/timer.h>
12 #include <linux/netfilter.h>
14 #include <linux/icmp.h>
15 #include <linux/seq_file.h>
17 #include <net/checksum.h>
18 #include <linux/netfilter_ipv4.h>
19 #include <net/netfilter/nf_conntrack_tuple.h>
20 #include <net/netfilter/nf_conntrack_l4proto.h>
21 #include <net/netfilter/nf_conntrack_core.h>
22 #include <net/netfilter/nf_conntrack_zones.h>
23 #include <net/netfilter/nf_log.h>
25 static unsigned int nf_ct_icmp_timeout __read_mostly
= 30*HZ
;
27 static inline struct nf_icmp_net
*icmp_pernet(struct net
*net
)
29 return &net
->ct
.nf_ct_proto
.icmp
;
32 static bool icmp_pkt_to_tuple(const struct sk_buff
*skb
, unsigned int dataoff
,
33 struct net
*net
, struct nf_conntrack_tuple
*tuple
)
35 const struct icmphdr
*hp
;
38 hp
= skb_header_pointer(skb
, dataoff
, sizeof(_hdr
), &_hdr
);
42 tuple
->dst
.u
.icmp
.type
= hp
->type
;
43 tuple
->src
.u
.icmp
.id
= hp
->un
.echo
.id
;
44 tuple
->dst
.u
.icmp
.code
= hp
->code
;
49 /* Add 1; spaces filled with 0. */
50 static const u_int8_t invmap
[] = {
51 [ICMP_ECHO
] = ICMP_ECHOREPLY
+ 1,
52 [ICMP_ECHOREPLY
] = ICMP_ECHO
+ 1,
53 [ICMP_TIMESTAMP
] = ICMP_TIMESTAMPREPLY
+ 1,
54 [ICMP_TIMESTAMPREPLY
] = ICMP_TIMESTAMP
+ 1,
55 [ICMP_INFO_REQUEST
] = ICMP_INFO_REPLY
+ 1,
56 [ICMP_INFO_REPLY
] = ICMP_INFO_REQUEST
+ 1,
57 [ICMP_ADDRESS
] = ICMP_ADDRESSREPLY
+ 1,
58 [ICMP_ADDRESSREPLY
] = ICMP_ADDRESS
+ 1
61 static bool icmp_invert_tuple(struct nf_conntrack_tuple
*tuple
,
62 const struct nf_conntrack_tuple
*orig
)
64 if (orig
->dst
.u
.icmp
.type
>= sizeof(invmap
) ||
65 !invmap
[orig
->dst
.u
.icmp
.type
])
68 tuple
->src
.u
.icmp
.id
= orig
->src
.u
.icmp
.id
;
69 tuple
->dst
.u
.icmp
.type
= invmap
[orig
->dst
.u
.icmp
.type
] - 1;
70 tuple
->dst
.u
.icmp
.code
= orig
->dst
.u
.icmp
.code
;
74 /* Print out the per-protocol part of the tuple. */
75 static void icmp_print_tuple(struct seq_file
*s
,
76 const struct nf_conntrack_tuple
*tuple
)
78 seq_printf(s
, "type=%u code=%u id=%u ",
79 tuple
->dst
.u
.icmp
.type
,
80 tuple
->dst
.u
.icmp
.code
,
81 ntohs(tuple
->src
.u
.icmp
.id
));
84 static unsigned int *icmp_get_timeouts(struct net
*net
)
86 return &icmp_pernet(net
)->timeout
;
89 /* Returns verdict for packet, or -1 for invalid. */
90 static int icmp_packet(struct nf_conn
*ct
,
91 const struct sk_buff
*skb
,
93 enum ip_conntrack_info ctinfo
,
96 unsigned int *timeout
)
98 /* Do not immediately delete the connection after the first
99 successful reply to avoid excessive conntrackd traffic
100 and also to handle correctly ICMP echo reply duplicates. */
101 nf_ct_refresh_acct(ct
, ctinfo
, skb
, *timeout
);
106 /* Called when a new connection for this protocol found. */
107 static bool icmp_new(struct nf_conn
*ct
, const struct sk_buff
*skb
,
108 unsigned int dataoff
, unsigned int *timeouts
)
110 static const u_int8_t valid_new
[] = {
112 [ICMP_TIMESTAMP
] = 1,
113 [ICMP_INFO_REQUEST
] = 1,
117 if (ct
->tuplehash
[0].tuple
.dst
.u
.icmp
.type
>= sizeof(valid_new
) ||
118 !valid_new
[ct
->tuplehash
[0].tuple
.dst
.u
.icmp
.type
]) {
119 /* Can't create a new ICMP `conn' with this. */
120 pr_debug("icmp: can't create new conn with type %u\n",
121 ct
->tuplehash
[0].tuple
.dst
.u
.icmp
.type
);
122 nf_ct_dump_tuple_ip(&ct
->tuplehash
[0].tuple
);
128 /* Returns conntrack if it dealt with ICMP, and filled in skb fields */
130 icmp_error_message(struct net
*net
, struct nf_conn
*tmpl
, struct sk_buff
*skb
,
131 unsigned int hooknum
)
133 struct nf_conntrack_tuple innertuple
, origtuple
;
134 const struct nf_conntrack_l4proto
*innerproto
;
135 const struct nf_conntrack_tuple_hash
*h
;
136 const struct nf_conntrack_zone
*zone
;
137 enum ip_conntrack_info ctinfo
;
138 struct nf_conntrack_zone tmp
;
140 NF_CT_ASSERT(!skb_nfct(skb
));
141 zone
= nf_ct_zone_tmpl(tmpl
, skb
, &tmp
);
143 /* Are they talking about one of our connections? */
144 if (!nf_ct_get_tuplepr(skb
,
145 skb_network_offset(skb
) + ip_hdrlen(skb
)
146 + sizeof(struct icmphdr
),
147 PF_INET
, net
, &origtuple
)) {
148 pr_debug("icmp_error_message: failed to get tuple\n");
152 /* rcu_read_lock()ed by nf_hook_thresh */
153 innerproto
= __nf_ct_l4proto_find(PF_INET
, origtuple
.dst
.protonum
);
155 /* Ordinarily, we'd expect the inverted tupleproto, but it's
156 been preserved inside the ICMP. */
157 if (!nf_ct_invert_tuple(&innertuple
, &origtuple
,
158 &nf_conntrack_l3proto_ipv4
, innerproto
)) {
159 pr_debug("icmp_error_message: no match\n");
163 ctinfo
= IP_CT_RELATED
;
165 h
= nf_conntrack_find_get(net
, zone
, &innertuple
);
167 pr_debug("icmp_error_message: no match\n");
171 if (NF_CT_DIRECTION(h
) == IP_CT_DIR_REPLY
)
172 ctinfo
+= IP_CT_IS_REPLY
;
174 /* Update skb to refer to this connection */
175 skb
->nfct
= &nf_ct_tuplehash_to_ctrack(h
)->ct_general
;
176 skb
->nfctinfo
= ctinfo
;
180 /* Small and modified version of icmp_rcv */
182 icmp_error(struct net
*net
, struct nf_conn
*tmpl
,
183 struct sk_buff
*skb
, unsigned int dataoff
,
184 u8 pf
, unsigned int hooknum
)
186 const struct icmphdr
*icmph
;
189 /* Not enough header? */
190 icmph
= skb_header_pointer(skb
, ip_hdrlen(skb
), sizeof(_ih
), &_ih
);
192 if (LOG_INVALID(net
, IPPROTO_ICMP
))
193 nf_log_packet(net
, PF_INET
, 0, skb
, NULL
, NULL
,
194 NULL
, "nf_ct_icmp: short packet ");
198 /* See ip_conntrack_proto_tcp.c */
199 if (net
->ct
.sysctl_checksum
&& hooknum
== NF_INET_PRE_ROUTING
&&
200 nf_ip_checksum(skb
, hooknum
, dataoff
, 0)) {
201 if (LOG_INVALID(net
, IPPROTO_ICMP
))
202 nf_log_packet(net
, PF_INET
, 0, skb
, NULL
, NULL
, NULL
,
203 "nf_ct_icmp: bad HW ICMP checksum ");
208 * 18 is the highest 'known' ICMP type. Anything else is a mystery
210 * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently
213 if (icmph
->type
> NR_ICMP_TYPES
) {
214 if (LOG_INVALID(net
, IPPROTO_ICMP
))
215 nf_log_packet(net
, PF_INET
, 0, skb
, NULL
, NULL
, NULL
,
216 "nf_ct_icmp: invalid ICMP type ");
220 /* Need to track icmp error message? */
221 if (icmph
->type
!= ICMP_DEST_UNREACH
&&
222 icmph
->type
!= ICMP_SOURCE_QUENCH
&&
223 icmph
->type
!= ICMP_TIME_EXCEEDED
&&
224 icmph
->type
!= ICMP_PARAMETERPROB
&&
225 icmph
->type
!= ICMP_REDIRECT
)
228 return icmp_error_message(net
, tmpl
, skb
, hooknum
);
231 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
233 #include <linux/netfilter/nfnetlink.h>
234 #include <linux/netfilter/nfnetlink_conntrack.h>
236 static int icmp_tuple_to_nlattr(struct sk_buff
*skb
,
237 const struct nf_conntrack_tuple
*t
)
239 if (nla_put_be16(skb
, CTA_PROTO_ICMP_ID
, t
->src
.u
.icmp
.id
) ||
240 nla_put_u8(skb
, CTA_PROTO_ICMP_TYPE
, t
->dst
.u
.icmp
.type
) ||
241 nla_put_u8(skb
, CTA_PROTO_ICMP_CODE
, t
->dst
.u
.icmp
.code
))
242 goto nla_put_failure
;
249 static const struct nla_policy icmp_nla_policy
[CTA_PROTO_MAX
+1] = {
250 [CTA_PROTO_ICMP_TYPE
] = { .type
= NLA_U8
},
251 [CTA_PROTO_ICMP_CODE
] = { .type
= NLA_U8
},
252 [CTA_PROTO_ICMP_ID
] = { .type
= NLA_U16
},
255 static int icmp_nlattr_to_tuple(struct nlattr
*tb
[],
256 struct nf_conntrack_tuple
*tuple
)
258 if (!tb
[CTA_PROTO_ICMP_TYPE
] ||
259 !tb
[CTA_PROTO_ICMP_CODE
] ||
260 !tb
[CTA_PROTO_ICMP_ID
])
263 tuple
->dst
.u
.icmp
.type
= nla_get_u8(tb
[CTA_PROTO_ICMP_TYPE
]);
264 tuple
->dst
.u
.icmp
.code
= nla_get_u8(tb
[CTA_PROTO_ICMP_CODE
]);
265 tuple
->src
.u
.icmp
.id
= nla_get_be16(tb
[CTA_PROTO_ICMP_ID
]);
267 if (tuple
->dst
.u
.icmp
.type
>= sizeof(invmap
) ||
268 !invmap
[tuple
->dst
.u
.icmp
.type
])
274 static int icmp_nlattr_tuple_size(void)
276 return nla_policy_len(icmp_nla_policy
, CTA_PROTO_MAX
+ 1);
280 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
282 #include <linux/netfilter/nfnetlink.h>
283 #include <linux/netfilter/nfnetlink_cttimeout.h>
285 static int icmp_timeout_nlattr_to_obj(struct nlattr
*tb
[],
286 struct net
*net
, void *data
)
288 unsigned int *timeout
= data
;
289 struct nf_icmp_net
*in
= icmp_pernet(net
);
291 if (tb
[CTA_TIMEOUT_ICMP_TIMEOUT
]) {
293 ntohl(nla_get_be32(tb
[CTA_TIMEOUT_ICMP_TIMEOUT
])) * HZ
;
295 /* Set default ICMP timeout. */
296 *timeout
= in
->timeout
;
302 icmp_timeout_obj_to_nlattr(struct sk_buff
*skb
, const void *data
)
304 const unsigned int *timeout
= data
;
306 if (nla_put_be32(skb
, CTA_TIMEOUT_ICMP_TIMEOUT
, htonl(*timeout
/ HZ
)))
307 goto nla_put_failure
;
314 static const struct nla_policy
315 icmp_timeout_nla_policy
[CTA_TIMEOUT_ICMP_MAX
+1] = {
316 [CTA_TIMEOUT_ICMP_TIMEOUT
] = { .type
= NLA_U32
},
318 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
321 static struct ctl_table icmp_sysctl_table
[] = {
323 .procname
= "nf_conntrack_icmp_timeout",
324 .maxlen
= sizeof(unsigned int),
326 .proc_handler
= proc_dointvec_jiffies
,
330 #endif /* CONFIG_SYSCTL */
332 static int icmp_kmemdup_sysctl_table(struct nf_proto_net
*pn
,
333 struct nf_icmp_net
*in
)
336 pn
->ctl_table
= kmemdup(icmp_sysctl_table
,
337 sizeof(icmp_sysctl_table
),
342 pn
->ctl_table
[0].data
= &in
->timeout
;
347 static int icmp_init_net(struct net
*net
, u_int16_t proto
)
349 struct nf_icmp_net
*in
= icmp_pernet(net
);
350 struct nf_proto_net
*pn
= &in
->pn
;
352 in
->timeout
= nf_ct_icmp_timeout
;
354 return icmp_kmemdup_sysctl_table(pn
, in
);
357 static struct nf_proto_net
*icmp_get_net_proto(struct net
*net
)
359 return &net
->ct
.nf_ct_proto
.icmp
.pn
;
362 struct nf_conntrack_l4proto nf_conntrack_l4proto_icmp __read_mostly
=
365 .l4proto
= IPPROTO_ICMP
,
367 .pkt_to_tuple
= icmp_pkt_to_tuple
,
368 .invert_tuple
= icmp_invert_tuple
,
369 .print_tuple
= icmp_print_tuple
,
370 .packet
= icmp_packet
,
371 .get_timeouts
= icmp_get_timeouts
,
376 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
377 .tuple_to_nlattr
= icmp_tuple_to_nlattr
,
378 .nlattr_tuple_size
= icmp_nlattr_tuple_size
,
379 .nlattr_to_tuple
= icmp_nlattr_to_tuple
,
380 .nla_policy
= icmp_nla_policy
,
382 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
384 .nlattr_to_obj
= icmp_timeout_nlattr_to_obj
,
385 .obj_to_nlattr
= icmp_timeout_obj_to_nlattr
,
386 .nlattr_max
= CTA_TIMEOUT_ICMP_MAX
,
387 .obj_size
= sizeof(unsigned int),
388 .nla_policy
= icmp_timeout_nla_policy
,
390 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
391 .init_net
= icmp_init_net
,
392 .get_net_proto
= icmp_get_net_proto
,