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>
11 #include <linux/netfilter.h>
12 #include <linux/module.h>
13 #include <linux/skbuff.h>
14 #include <linux/icmp.h>
15 #include <linux/sysctl.h>
16 #include <net/route.h>
19 #include <linux/netfilter_ipv4.h>
20 #include <net/netfilter/nf_conntrack.h>
21 #include <net/netfilter/nf_conntrack_helper.h>
22 #include <net/netfilter/nf_conntrack_l4proto.h>
23 #include <net/netfilter/nf_conntrack_l3proto.h>
24 #include <net/netfilter/nf_conntrack_core.h>
25 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
27 static int ipv4_pkt_to_tuple(const struct sk_buff
*skb
, unsigned int nhoff
,
28 struct nf_conntrack_tuple
*tuple
)
32 ap
= skb_header_pointer(skb
, nhoff
+ offsetof(struct iphdr
, saddr
),
33 sizeof(u_int32_t
) * 2, _addrs
);
37 tuple
->src
.u3
.ip
= ap
[0];
38 tuple
->dst
.u3
.ip
= ap
[1];
43 static int ipv4_invert_tuple(struct nf_conntrack_tuple
*tuple
,
44 const struct nf_conntrack_tuple
*orig
)
46 tuple
->src
.u3
.ip
= orig
->dst
.u3
.ip
;
47 tuple
->dst
.u3
.ip
= orig
->src
.u3
.ip
;
52 static int ipv4_print_tuple(struct seq_file
*s
,
53 const struct nf_conntrack_tuple
*tuple
)
55 return seq_printf(s
, "src=%u.%u.%u.%u dst=%u.%u.%u.%u ",
56 NIPQUAD(tuple
->src
.u3
.ip
),
57 NIPQUAD(tuple
->dst
.u3
.ip
));
60 /* Returns new sk_buff, or NULL */
61 static int nf_ct_ipv4_gather_frags(struct sk_buff
*skb
, u_int32_t user
)
68 err
= ip_defrag(skb
, user
);
72 ip_send_check(ip_hdr(skb
));
77 static int ipv4_get_l4proto(const struct sk_buff
*skb
, unsigned int nhoff
,
78 unsigned int *dataoff
, u_int8_t
*protonum
)
80 const struct iphdr
*iph
;
83 iph
= skb_header_pointer(skb
, nhoff
, sizeof(_iph
), &_iph
);
87 /* Conntrack defragments packets, we might still see fragments
88 * inside ICMP packets though. */
89 if (iph
->frag_off
& htons(IP_OFFSET
))
92 *dataoff
= nhoff
+ (iph
->ihl
<< 2);
93 *protonum
= iph
->protocol
;
98 static unsigned int ipv4_confirm(unsigned int hooknum
,
100 const struct net_device
*in
,
101 const struct net_device
*out
,
102 int (*okfn
)(struct sk_buff
*))
104 /* We've seen it coming out the other side: confirm it */
105 return nf_conntrack_confirm(skb
);
108 static unsigned int ipv4_conntrack_help(unsigned int hooknum
,
110 const struct net_device
*in
,
111 const struct net_device
*out
,
112 int (*okfn
)(struct sk_buff
*))
115 enum ip_conntrack_info ctinfo
;
116 const struct nf_conn_help
*help
;
117 const struct nf_conntrack_helper
*helper
;
119 /* This is where we call the helper: as the packet goes out. */
120 ct
= nf_ct_get(skb
, &ctinfo
);
121 if (!ct
|| ctinfo
== IP_CT_RELATED
+ IP_CT_IS_REPLY
)
124 help
= nfct_help(ct
);
127 /* rcu_read_lock()ed by nf_hook_slow */
128 helper
= rcu_dereference(help
->helper
);
131 return helper
->help(skb
, skb_network_offset(skb
) + ip_hdrlen(skb
),
135 static unsigned int ipv4_conntrack_defrag(unsigned int hooknum
,
137 const struct net_device
*in
,
138 const struct net_device
*out
,
139 int (*okfn
)(struct sk_buff
*))
141 /* Previously seen (loopback)? Ignore. Do this before
146 /* Gather fragments. */
147 if (ip_hdr(skb
)->frag_off
& htons(IP_MF
| IP_OFFSET
)) {
148 if (nf_ct_ipv4_gather_frags(skb
,
149 hooknum
== NF_INET_PRE_ROUTING
?
150 IP_DEFRAG_CONNTRACK_IN
:
151 IP_DEFRAG_CONNTRACK_OUT
))
157 static unsigned int ipv4_conntrack_in(unsigned int hooknum
,
159 const struct net_device
*in
,
160 const struct net_device
*out
,
161 int (*okfn
)(struct sk_buff
*))
163 return nf_conntrack_in(PF_INET
, hooknum
, skb
);
166 static unsigned int ipv4_conntrack_local(unsigned int hooknum
,
168 const struct net_device
*in
,
169 const struct net_device
*out
,
170 int (*okfn
)(struct sk_buff
*))
172 /* root is playing with raw sockets. */
173 if (skb
->len
< sizeof(struct iphdr
) ||
174 ip_hdrlen(skb
) < sizeof(struct iphdr
)) {
176 printk("ipt_hook: happy cracking.\n");
179 return nf_conntrack_in(PF_INET
, hooknum
, skb
);
182 /* Connection tracking may drop packets, but never alters them, so
183 make it the first hook. */
184 static struct nf_hook_ops ipv4_conntrack_ops
[] __read_mostly
= {
186 .hook
= ipv4_conntrack_defrag
,
187 .owner
= THIS_MODULE
,
189 .hooknum
= NF_INET_PRE_ROUTING
,
190 .priority
= NF_IP_PRI_CONNTRACK_DEFRAG
,
193 .hook
= ipv4_conntrack_in
,
194 .owner
= THIS_MODULE
,
196 .hooknum
= NF_INET_PRE_ROUTING
,
197 .priority
= NF_IP_PRI_CONNTRACK
,
200 .hook
= ipv4_conntrack_defrag
,
201 .owner
= THIS_MODULE
,
203 .hooknum
= NF_INET_LOCAL_OUT
,
204 .priority
= NF_IP_PRI_CONNTRACK_DEFRAG
,
207 .hook
= ipv4_conntrack_local
,
208 .owner
= THIS_MODULE
,
210 .hooknum
= NF_INET_LOCAL_OUT
,
211 .priority
= NF_IP_PRI_CONNTRACK
,
214 .hook
= ipv4_conntrack_help
,
215 .owner
= THIS_MODULE
,
217 .hooknum
= NF_INET_POST_ROUTING
,
218 .priority
= NF_IP_PRI_CONNTRACK_HELPER
,
221 .hook
= ipv4_conntrack_help
,
222 .owner
= THIS_MODULE
,
224 .hooknum
= NF_INET_LOCAL_IN
,
225 .priority
= NF_IP_PRI_CONNTRACK_HELPER
,
228 .hook
= ipv4_confirm
,
229 .owner
= THIS_MODULE
,
231 .hooknum
= NF_INET_POST_ROUTING
,
232 .priority
= NF_IP_PRI_CONNTRACK_CONFIRM
,
235 .hook
= ipv4_confirm
,
236 .owner
= THIS_MODULE
,
238 .hooknum
= NF_INET_LOCAL_IN
,
239 .priority
= NF_IP_PRI_CONNTRACK_CONFIRM
,
243 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
244 static int log_invalid_proto_min
= 0;
245 static int log_invalid_proto_max
= 255;
247 static ctl_table ip_ct_sysctl_table
[] = {
249 .ctl_name
= NET_IPV4_NF_CONNTRACK_MAX
,
250 .procname
= "ip_conntrack_max",
251 .data
= &nf_conntrack_max
,
252 .maxlen
= sizeof(int),
254 .proc_handler
= &proc_dointvec
,
257 .ctl_name
= NET_IPV4_NF_CONNTRACK_COUNT
,
258 .procname
= "ip_conntrack_count",
259 .data
= &nf_conntrack_count
,
260 .maxlen
= sizeof(int),
262 .proc_handler
= &proc_dointvec
,
265 .ctl_name
= NET_IPV4_NF_CONNTRACK_BUCKETS
,
266 .procname
= "ip_conntrack_buckets",
267 .data
= &nf_conntrack_htable_size
,
268 .maxlen
= sizeof(unsigned int),
270 .proc_handler
= &proc_dointvec
,
273 .ctl_name
= NET_IPV4_NF_CONNTRACK_CHECKSUM
,
274 .procname
= "ip_conntrack_checksum",
275 .data
= &nf_conntrack_checksum
,
276 .maxlen
= sizeof(int),
278 .proc_handler
= &proc_dointvec
,
281 .ctl_name
= NET_IPV4_NF_CONNTRACK_LOG_INVALID
,
282 .procname
= "ip_conntrack_log_invalid",
283 .data
= &nf_ct_log_invalid
,
284 .maxlen
= sizeof(unsigned int),
286 .proc_handler
= &proc_dointvec_minmax
,
287 .strategy
= &sysctl_intvec
,
288 .extra1
= &log_invalid_proto_min
,
289 .extra2
= &log_invalid_proto_max
,
295 #endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */
297 /* Fast function for those who don't want to parse /proc (and I don't
299 /* Reversing the socket's dst/src point of view gives us the reply
302 getorigdst(struct sock
*sk
, int optval
, void __user
*user
, int *len
)
304 const struct inet_sock
*inet
= inet_sk(sk
);
305 const struct nf_conntrack_tuple_hash
*h
;
306 struct nf_conntrack_tuple tuple
;
308 memset(&tuple
, 0, sizeof(tuple
));
309 tuple
.src
.u3
.ip
= inet
->rcv_saddr
;
310 tuple
.src
.u
.tcp
.port
= inet
->sport
;
311 tuple
.dst
.u3
.ip
= inet
->daddr
;
312 tuple
.dst
.u
.tcp
.port
= inet
->dport
;
313 tuple
.src
.l3num
= PF_INET
;
314 tuple
.dst
.protonum
= IPPROTO_TCP
;
316 /* We only do TCP at the moment: is there a better way? */
317 if (strcmp(sk
->sk_prot
->name
, "TCP")) {
318 pr_debug("SO_ORIGINAL_DST: Not a TCP socket\n");
322 if ((unsigned int) *len
< sizeof(struct sockaddr_in
)) {
323 pr_debug("SO_ORIGINAL_DST: len %d not %Zu\n",
324 *len
, sizeof(struct sockaddr_in
));
328 h
= nf_conntrack_find_get(&tuple
);
330 struct sockaddr_in sin
;
331 struct nf_conn
*ct
= nf_ct_tuplehash_to_ctrack(h
);
333 sin
.sin_family
= AF_INET
;
334 sin
.sin_port
= ct
->tuplehash
[IP_CT_DIR_ORIGINAL
]
335 .tuple
.dst
.u
.tcp
.port
;
336 sin
.sin_addr
.s_addr
= ct
->tuplehash
[IP_CT_DIR_ORIGINAL
]
338 memset(sin
.sin_zero
, 0, sizeof(sin
.sin_zero
));
340 pr_debug("SO_ORIGINAL_DST: %u.%u.%u.%u %u\n",
341 NIPQUAD(sin
.sin_addr
.s_addr
), ntohs(sin
.sin_port
));
343 if (copy_to_user(user
, &sin
, sizeof(sin
)) != 0)
348 pr_debug("SO_ORIGINAL_DST: Can't find %u.%u.%u.%u/%u-%u.%u.%u.%u/%u.\n",
349 NIPQUAD(tuple
.src
.u3
.ip
), ntohs(tuple
.src
.u
.tcp
.port
),
350 NIPQUAD(tuple
.dst
.u3
.ip
), ntohs(tuple
.dst
.u
.tcp
.port
));
354 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
356 #include <linux/netfilter/nfnetlink.h>
357 #include <linux/netfilter/nfnetlink_conntrack.h>
359 static int ipv4_tuple_to_nlattr(struct sk_buff
*skb
,
360 const struct nf_conntrack_tuple
*tuple
)
362 NLA_PUT_BE32(skb
, CTA_IP_V4_SRC
, tuple
->src
.u3
.ip
);
363 NLA_PUT_BE32(skb
, CTA_IP_V4_DST
, tuple
->dst
.u3
.ip
);
370 static const struct nla_policy ipv4_nla_policy
[CTA_IP_MAX
+1] = {
371 [CTA_IP_V4_SRC
] = { .type
= NLA_U32
},
372 [CTA_IP_V4_DST
] = { .type
= NLA_U32
},
375 static int ipv4_nlattr_to_tuple(struct nlattr
*tb
[],
376 struct nf_conntrack_tuple
*t
)
378 if (!tb
[CTA_IP_V4_SRC
] || !tb
[CTA_IP_V4_DST
])
381 t
->src
.u3
.ip
= nla_get_be32(tb
[CTA_IP_V4_SRC
]);
382 t
->dst
.u3
.ip
= nla_get_be32(tb
[CTA_IP_V4_DST
]);
388 static struct nf_sockopt_ops so_getorigdst
= {
390 .get_optmin
= SO_ORIGINAL_DST
,
391 .get_optmax
= SO_ORIGINAL_DST
+1,
393 .owner
= THIS_MODULE
,
396 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 __read_mostly
= {
399 .pkt_to_tuple
= ipv4_pkt_to_tuple
,
400 .invert_tuple
= ipv4_invert_tuple
,
401 .print_tuple
= ipv4_print_tuple
,
402 .get_l4proto
= ipv4_get_l4proto
,
403 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
404 .tuple_to_nlattr
= ipv4_tuple_to_nlattr
,
405 .nlattr_to_tuple
= ipv4_nlattr_to_tuple
,
406 .nla_policy
= ipv4_nla_policy
,
408 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
409 .ctl_table_path
= nf_net_ipv4_netfilter_sysctl_path
,
410 .ctl_table
= ip_ct_sysctl_table
,
415 module_param_call(hashsize
, nf_conntrack_set_hashsize
, param_get_uint
,
416 &nf_conntrack_htable_size
, 0600);
418 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET
));
419 MODULE_ALIAS("ip_conntrack");
420 MODULE_LICENSE("GPL");
422 static int __init
nf_conntrack_l3proto_ipv4_init(void)
428 ret
= nf_register_sockopt(&so_getorigdst
);
430 printk(KERN_ERR
"Unable to register netfilter socket option\n");
434 ret
= nf_conntrack_l4proto_register(&nf_conntrack_l4proto_tcp4
);
436 printk("nf_conntrack_ipv4: can't register tcp.\n");
437 goto cleanup_sockopt
;
440 ret
= nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udp4
);
442 printk("nf_conntrack_ipv4: can't register udp.\n");
446 ret
= nf_conntrack_l4proto_register(&nf_conntrack_l4proto_icmp
);
448 printk("nf_conntrack_ipv4: can't register icmp.\n");
452 ret
= nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4
);
454 printk("nf_conntrack_ipv4: can't register ipv4\n");
458 ret
= nf_register_hooks(ipv4_conntrack_ops
,
459 ARRAY_SIZE(ipv4_conntrack_ops
));
461 printk("nf_conntrack_ipv4: can't register hooks.\n");
464 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
465 ret
= nf_conntrack_ipv4_compat_init();
470 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
472 nf_unregister_hooks(ipv4_conntrack_ops
, ARRAY_SIZE(ipv4_conntrack_ops
));
475 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4
);
477 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp
);
479 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4
);
481 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4
);
483 nf_unregister_sockopt(&so_getorigdst
);
487 static void __exit
nf_conntrack_l3proto_ipv4_fini(void)
490 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
491 nf_conntrack_ipv4_compat_fini();
493 nf_unregister_hooks(ipv4_conntrack_ops
, ARRAY_SIZE(ipv4_conntrack_ops
));
494 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4
);
495 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp
);
496 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4
);
497 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4
);
498 nf_unregister_sockopt(&so_getorigdst
);
501 module_init(nf_conntrack_l3proto_ipv4_init
);
502 module_exit(nf_conntrack_l3proto_ipv4_fini
);
504 void need_ipv4_conntrack(void)
508 EXPORT_SYMBOL_GPL(need_ipv4_conntrack
);